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Home My WebLink About2023-04-03 City Council Request ►I+yyINYj+'ALI's Date: Monday, April 3, 2023 To: Honorable Mayor and City Council o-0 QQ From: ACTION ITEM Request: Request approval of $300,000 for purchasing a mobile air scrubber and continued support from Consor Engineering for an odor control study through the end of the current fiscal year. Time Estimate: Staff estimates 45 minutes to explain history and request. Background: Since 2017 the City has been contracting with Consor Engineering (formerly Murrysmith Engineering) on an odor study to understand the causes of sewer odor, the magnitude of odor, areas of odor generation, and the feasibility of different mitigation methods. Over the years, the odor study has determined that a significant portion of odor spikes experienced by the City can be traced back to point sources from permitted dischargers. In 2022 the City of Twin Falls partnered with a permitted discharger to conduct a pilot project dosing the waste stream with ferric chloride to reduce the concentration of soluble hydrogen sulfide in the sewer system. The attached Technical Memorandum presents the background, results, and conclusions from work completed in 2022 (Attachment 1). The next steps identified by the Technical Memorandum include the need to continue partnering with point sources to manage discharges, investigation of local limits, a trial of options available for vapor phase treatment, engineering and design, and rehabilitation of manholes. Based on the recommendations from the Technical Memorandum, the request to City Council is to purchase a mobile air scrubber with associated expenses of$150,000 (Attachment 2) and contract with Consor Engineering for $150,000 during the preliminary design phase (Attachment 3). Approval Process: Majority approval by City Council will authorize City Staff to use wastewater reserve funds to purchase a mobile air scrubbing unit and contract with Consor Engineering during the preliminary design phase. Budget Impact: Sufficient funds are available in the wastewater reserves to expend the unbudgeted amount of $300,000. Regulatory Impact: The purchase of a mobile air scrubber and continued support from Consor Engineering will allow the City to continue to partner with industrial users to understand better the sources and options available to address the odor problems. They will also help meet Strategic Plan Objectives EC1.4.3 "The City will continue to monitor collection systems for odors and mitigate through infrastructure improvements..." and EC1.4.4 "The City will explore creating standards for monitoring air quality particulate saturation and associated enforcement policies." History: N/A Analysis: N/A Conclusion: City Staff recommends that the Council authorize the purchase of a mobile air scrubber and associated expenses for $150,000 and execute a contract with Consor Engineering during the preliminary design phase of the odor control study through the end of the current fiscal year for $150,000. The total authorized amount of $300,000 will be taken from the wastewater reserve funds. Attachments: 1. 2) Mobile air scrubber 2. 3) Consor Engineering Scope of Work 3. 1) Technical Memorandum CityofTwinFallsOdorProject 2022Draft Integrity SKID-MOUNTED CARBON ADSORBER MUNICIPAL SYSTEMS (MCS Series) The IMS Model MCS carbon adsorber is a once-through activated carbon odor removal system designed to treat hydrogen sulfide (H-,S) &organic odors(VOCs) found in municipal wastewater collection systems and treatment processes. The MCS is a factory- assembled. skid-mounted odor control system complete with exhaust fan. damper. interconnecting ductwork. vessel. activated car- bon media and local control panel. All components are mounted. piped. and wired on an epoxy coated carbon steel skid. System is designed for continuous and automatic operation as well as manual operation as required. /'j .� SUPERIOR PERFORMANCE MEDIA tintegrity The IMS carbon systems are designed to work with a - _ wide selection of media: _ A" ■ Virgin activated carbon media for low odor levels �,p ■ High capacity carbon for higher H_S concentrations MCS F L O ELECTRICAL CONTROL PANEI MAJOR SYSTEM COMPONENTS ■ Epoxy Coated Steel Equipment Skid AN= 0 ■ FRP Exhaust Fan 1 ■ FRP Transition Duct GROVNDiNG WOO P1. ■ FRP Inlet Damper H-105 . al ■ FRP Carbon Adsorber Vessel WY106_t, and Exhaust Stack °Y107 ' ■ Activated Carbon Media 'AP DUCT a :x, ■ Electrical Control Panel MAW MCS Process & Instrumentation Diagram ©2016 INTEGRITY MUNICIPAL SYSTEMS ALL RIGHTS RESERVED HOW IT WORKS SYSTEM FEATURES & BENEFITS The exhaust fan operates continuously. pulling foul air from the process area and passing it through the carbon media.A volume control damper at ■ Superior non-corrosive material the system inlet allows regulation of airflow through the carbon adsorber. • Easy to operate ■ Suitable for outdoor installation Inside the vessel, the foul air flows through a densely packed bed of ac tivated carbon. The odorous compounds are removed from the airstream ' Fan sound enclosure (Optional) through a combination of physical adsorption and chemisorption. Odorous • Compact, skid-mounted design compounds are physically adsorbed in the carbon pores, and some may ■ Pre-assembled and factory tested undergo chemical reaction to form elemental sulfur and sulfuric acid. This process continues until the activated carbon pores are filled up and the odorous compounds break through and are released out the stack. MCS ACTIVATED CARBON ODOR CONTROL SYSTEM STANDARD MODEL DESIGN DATA Airfiow Vessel mCarbon Model Ibs lbs HP r r 11D 19'x 54" 6'-0"x 3'-11"x 9•0" 4 1000 1&0 1 NI 5 018 (190) (460 x 1370) (1830 x 1190 x 1830) (100) (450) (70) (.75) MCS.-024 200 24"x 56" 6'-0"x 3'-11"x 6'-2' 6 12co 280 1 (340) (610 x 1420) ,1830 x 1190 x 1880) (150) (5501 (130) 1.75) MC54"0 300 30"x S6, 7'4'x 4'-5"x 6'-2" 6 1500 440 2 (510) (760 x 2420) 12130 x 1350 x 1880) (1501 (680) (2001 (1.51 mcs-W6 425 36"x 56" 7r4r.x 4'-5"x 6'-5" 8 1700 640 2 (720) (910 x 2470) 12130 x 1350 x 1960) (200) (770) (290) (1,5) MCS•042 600 42"x 58" 9'-r x 5'-3"x 6'-5" 8 2300 870 2 110201 (1070 x 1470) (2770 x 1600 x 19601 (2001 (10401 (390) (1.51 750 48"x 60" 9'-1"x 5'-3"x W-11" 10 2600 2130 2 Mt5.048 (1270) 11220 x 1520) 12770x 1600x 21101 (250) (1180) (510) (13) MCS-054 1000 54"x 60" 10'4"x 6'-1"x 6"-11" 10 3200 1430 3 (1700) 11370 x 15201 (3070x 1850 x 2110) (250) (14SO) (650) (215) MCS 060 1250 60"x 62" 10'-1`"x 6'-1"x 7' 1" 12 3600 1770 3 (2120) 12525 x 1520) (3070 x 1850 x 2160) 1 (300) 1 (1630) (8.08) (2,25) 'Approximate weight is an estimate 13135 DANIELSON STREET,SUITE 204 POWAY,CA 92064 1 n tegri ty PHONE:(858)486-1620 FAX:(616)772-2693 www fntegr tyms.net MUNICIPAL SYSTEMS In tegrity PRODUCT LINE OVERVIEW MUNICIPAL SYSTEMS Integrity Municipal Systems (IMS) is a specialty engineering company devoted to the design and supply of innovative. pre- assembled, process solutions for the water and wastewater industry.With over 25 years of systems engineering innovation and project execution. the IMS team has the knowledge and dedication to tackle your odor control and chemical feed needs. IMS has achieved a reputation for producing unique. practical, and cost-effective solutions for our customers. We are committed to providing quality, service, and overall value that exceed your expectations. Lime Slaker Systems (A-758 & A-758 Plus) e The A-758 and A-758 Plus IMS Lime Slaker Systems provide continuous high volume _Auntegr4 i lime slurries (up to 8,000 Ibslhour)for industrial and municipal process pH adjustment, -- -= flocculation, and chemical reaction. The superior paste-type slaking technology consistently produces a higher strength and more reactive lime slurry resulting in more efficient and more economical use of the quicklime. Systems are factory assembled and tested for quick and o t easy installation, and include options for lime feed and grit removal. o Lime Slaker Feeders r Series 31-165 Gravimetric Feeder Series 32-215 Volumetric Feeder Series 32-300 Volumetric Feeder Chemical Feed Systems IMS chemical feed systems are pre-assembled. fully-functional chemical delivery systems for water treatment applications. These compact. user-friendly chemical skids include local storage tanks. full secondary containment, dosing pumps. instrumentation and controls. Systems are piped and wired at the factory for easy and quick hook-up. Fluoride Feed System © IMS Fluoride Feed Systems use sodium fluoride for community water fluoridation.They are designed with separate saturator and solution tanks. unlike conventional methods, to assure complete saturation, high reliability, low maintenance and ease of use. �In teyrrty Aqueous Ammonia Feed System ' IMS packaged Aqueous Ammonia Feed Systems are used in the formation of e �a� chloramines for disinfection.The system includes a heavy-duty pressure rated aqueous ammonia storage tank.integral ammonia fume scrubber, peristaltic dosing pump, instrumentation and controls in a fully contained, pre-assembled tnroy.iry skid. Optional enclosure.shown right, is ideal for outdoor or remote locations.The FRP shelter houses the equipment in an air conditioned environment and comes complete with lighting, ventilation fan,and breaker panel. ©2018 INTEGRITY MUNICIPAL SYSTEMS ALL RIGHTS RESERVED Odor Control Systems Standardized, pre-engineered, factory assembled odor control systems for treating odors at sewage pump stations and wastewater treatment plants. Systems are simple to install. reducing installed cost and delivery time. Jr Biological Odor Control Systems _ The I-BOx",1 Biological Odor Control System(Patent Pending) uses a two-stage process with a biological stage to remove 99%of the hydrogen sulfide(H,S),followed by an activated carbon polishing stage to remove residual H,S and organic odors. Standard models are available to treat up to 5,000 cfrm(8,500 m�'h)of odorous air. Carbon Odor Control Systems The carbon adsorber odor control systems consist of an exhaust fan,damper, interconnecting ductwork,vessel with activated carbon(3 ft, bed)and a control panel. The carbon odor control systems are designed to work with a wide selection of media:virgin activated carbon for low odor level,and high capacity carbon for higher H 2 S concentrations. MCS Carbon Odor Control System _ ❑,�r� Standard models are available to treat up to 1,400 cfm(2400 m='h)of odorous 0 air in a single carbon stage. 1 7� BCS Carbon Odor Control System Standard models treat up to 6,800 cfm(11600 rn'?h) in a single carbon stage i and up to 20,000 cfm(34000 m ?h)in a dual carbon bed system. Emergency Chlorine Scrubbers IMS wet emergency chlorine scrubber systems contain and treat accidental releases of chlorine gas. limiting the atmospheric release of chlorine to less than 1 ppm. The compact scrubber systems are factory pre-assembled. piped, wired and tested. with a low profile suitable for either indoor or outdoor installation. The system design surpasses the requirements of the Uniform Fire Code. EVS-150 --W This multi-stage wet scrubber system treats chlorine vapors from a bank of 1501b(70kg)chlorine cylinders.at leak rates of 28 Ibs'min or more. EVLS-2000 This multi-stage wet scrubber system treats up to 3 tons of chlorine vapor.at leak rates of 100 Ibs''min or more. cl EVS-2000C The EVS-2000C emergency chlorine scrubber is a multi-stage wet scrubber system designed to treat up to 1 ton of chlorine vapor.at leak rates of 100 Ibs'min or more. 13135 DANIELSON STREET,SUITE 204 POWAY,CA92064 1n tegrlty 04/09/2018 Rev 10 PHONE (858)486-1620 FAX (858)486-1659 www integrityms net MUNICIPAL SYSTEMS Integrity MUNICIPAL SYSTEMS Table 1: Design Specifications, Performance Requirements and Major System Components I. DESIGN SPECIFICATIONS AND PERFORMANCE REQUIREMENTS: MCS-042S Design AirFlow Rate,cfm 650 Average Inlet H,,S Concentration, ppm 10 Peak Inlet H2S Concentration, ppm 75 Maximum Outlet HAS Concentration, ppm 0.1 Removal Efficiency,% 99 II. MAJOR SYSTEM COMPONENTS: Exhaust Fan AirFlow, cfm 650 SP at Fan Inlet, in W.C. 1.0 Pressure Drop across Carbon Media,in W.C. 5.0 Total SP,in W.C. 6.0 Brake Horspower, BHP 1.83 Motor Horsepower, HP 2.0 Interconnecting Ductwork and Damper Included Carbon Adsorber Vessel Diameter,ft 3.5 Number of Beds 1 Superficial Velocity,fpm 68 Straight Shell Height,ft 4.8 Carbon Bed Height,ft 3.0 Carbon Media, Ibs 865 Carbon Media Vapor Phase, Bituminous Coal,0.3 g of H,,S/cc of Carbon Capacity Included Exhaust Stack Included Electrical Control Panel Included Integrity MUNICIPAL SYSTEMS Table 2: Estimated Carbon Life CARBON REPLACEMENT M CS-042S At Average Inlet H25 Concentration Carbon Capacity,g H,S/cc carbon 0.3 Carbon Density,g carbon/cc carbon 0.5 Carbon Capacity,g H,,S/g carbon 0.6 Total Carbon in System, Ibs 865 Usable Carbon at Breakthrough (80%of capacity), Ibs 692 Lbs of H S Adsorbed for Usuable Carbon in System 433 Lbs H2S/day 0.8 Carbon Life, days 524 No.of Carbon Changes/year 0.7 At Peak Inlet HZS Concentration Carbon Capacity,g H2S/cc carbon 0.3 Carbon Density,g carbon/cc carbon 0.5 Carbon Capacity,g H,S/g carbon 0.6 Total Carbon in System, Ibs 865 Usable Carbon at Breakthrough (80%of capacity), Ibs 692 Lbs of H S Adsorbed for Usuable Carbon in System 433 Lbs H2S/day 6.2 Carbon Life, days 70 No.of Carbon Changes/year 5.2 CAUTION: The life of carbon depends on several factors including all odor compounds in the incoming air stream which can be adsorbed on the carbon,and the humidity of the airstream.The carbon life is presented as an estimate only and IMS does not guarantee any life cycle for the carbon. / ! , § /. _ [ §:| \ , ) / [ s� � Ill 4Al ,] ! . 2§ #§ | � 1.0 W. § ! ® / ; \ §k . . . . � rm / \ &§ { \ #I ) . » � °� t / I / ! ; ! « © }; 0 � ! # f ! § ; ■ / x 2 } ° 0000 § 0000 /\ 7 z 5 §§■@!, ! 2 ) _ § § \k \ ! & ! . @ § 2 � > ) d �� § p U m Q �I pp o d� om 00m o z gH 2 E C 7 7f 8 N w > q m m > @ m N gg � b w I\ �I m 0 I \ y Z N ON m I I w(9 N U C M y I p w W w m x 1 u m0 H�J OC \\ i I`I ZOrc �w f y O f 0 p= I \I Z U Y Q y Q W y —111 I V f N f Z LU \ I gg Z b n J I LL= a x U o o LL wo N a w U 10 O p O w 0 o m0 I LL LL> I 9L I LL I I o I LL ...........,------- _,__ _._.---------------._,_._,__C N � m 0 m F W _ W Z N N 1 u K C a=m ¢O 0 Apo F� m I Nmo Oz � ojyao p�Cwm� O f m O p.J Oz�m1101 u�NZyW - �w�gN; .0 Jy .om o w zaa?oam $ o p z F \ |§ §|. §!�. !!| � 2§; : % § |��N a m !¥4 Amm 1pq�mw Wn \ qG$'° z«mom O ] { § < -§ § - 6� 4 � h ° \ � K ! §� } 0 `$ m EL \ : '§ $B ( $ QB \� ; § °� }( §� ! ! �ff« ' @§ oz ] /o\ k§w} /�) }\\!F(" o5e ex�,■5 �!) (222��Ir - !!` ! § e o<=uo�� z 6` B»� Zak§-11111I/ o zoo | Lu < ]» - §§MHF6 £> )/ r /27M§E)M��oo !{ _ 2E�o�o§n-§oo _w<ww¥,wai�a ` � § � / ! , § /. _ [ §:| \ , ) / [ s� � Ill 4Al ,] ! . 2§ #§ | � 1.0 W. § ! ® / ; \ §k . . . . � rm / \ &§ { \ #I ) . » � °� t / I / ! ; ! « © }; 0 � ! # f ! § ; ■ / x 2 } ° 0000 § 0000 /\ 7 z 5 §§■@!, ! 2 ) _ § § \k \ ! & ! . @ § 2 � > ) d �� § DRAFT EXHIBIT A SCOPE OF WORK GRANDVIEW ODOR CONTROL PROJECT 2023 CITY OF TWIN FALLS Introduction/General/Background This Scope of Services has been separated into four tasks for clarity and is described in detail below. Project Understanding and Assumptions The City of Twin Falls' (City) large diameter Grandview Sewer Trunkline has high hydrogen sulfide concentrations leading to corrosion and odor problems. The Grandview Trunkline runs in Canyon Rim Road (from manhole 81-28), up Grandview Drive, past County West building, and down into Rock Creek (to manhole 131-28). There have been complaints from the general populace about odors as well as known corrosion issues along the entire length of the nearly 6-mile pipeline corridor.The goal of this project is to mitigate both existing odor and associated corrosion control impacts on this sewer collection mainline. In previous scope of work, Consor North America Inc. (Consultant) completed collection of general system sampling (liquid and vapor phase)to help delineate and quantify problems areas. With the problem areas delineated, site specific sampling and supplemental testing is needed to analyze, compare, and select the preferred mitigation option(s)for future design. The City has requested Consultant to provide refined collection system sampling (liquid, vapor phase and pressure), evaluation of vapor phase and liquid phase treatment options, concept level development of solution alternatives with associated capital and life cycle costs estimates, selection of the preferred mitigation option(s),as well as interim solution bid document creation support. Based on the results of the phase of work, more than a single mitigation measure is anticipated to be necessary to address the existing odor and corrosion issues. Scope of Services Consultant will perform the following services. Task 1 - Project Management Objective Provide overall leadership and team strategic guidance aligned with City of Twin Falls(City) staff objectives. Coordinate, monitor, and control the project resources to meet the technical, communication, and contractual obligations required for developing and implementing the project scope. Consor• March 2023• Grandview Odor Control Project 2023• City of Twin Falls Scope of Work• 1 DRAFT Activities 1.1 Invoices/Status Reports Consultant will prepare monthly invoices, including expenditures by task, hours worked by project personnel, and other direct expenses with the associated backup documentation. Monthly status reports will accompany each invoice and include comparisons of monthly expenditures and cumulative charges to budget by Task, including cost-to-complete, earned value, cash flow, and certified firm participation. 1.2 Coordination with the Owner Consultant will maintain communication with the City through meetings via voice, email, and fax communication. 1.3 Management and Coordination of Staff Consultant will manage and coordinate the technical and scope issues of the overall project. Progress meetings will be conducted as appropriate. In addition, a Health and Safety Plan (HASP) will be created that is custom to this project. It is the Consultant's policy to promote and foster a safe work environment for the team both inside the office and in the field. The HASP will align with all local Occupation Health and Safety Administration (OSHA) requirements, client safety plans and program, and contractor safety plans. Based on the Consultant's assessment of the probably risks and demands of this project, the HASP will consist of the Consor Office Safety Handbook plus the Driver Safety Handbook, and a site-specific plan to address potential, probable hazards. The purpose is to proactively aid employees in identifying, understanding, and mitigatingthe risks they are likely to encounter when working on this project,especially when visiting a site. The Project Manager (PM) will establish appropriate precautions and communicate those to the project team through the designated specific safety person (in most cases this will be the PM). In addition to the HASP,the safety plans of the client are attached as appendices to this document and will supersede the HASP when staff are at project locations. 1.4 Kickoff Meeting Consultant will coordinate with subconsultants on specific tasks, scope, and budget. Conduct progress meetings as appropriate. Task Deliverables y Consultant shall deliver to the City a monthly invoice and status report covering: o Work on the project performed during the previous month. o Meetings attended. o Problems encountered and actions taken for their resolution. o Potential impacts to submittal dates, budget shortfalls or optional services. o Budget Analysis. o Issues requiring project team action. Consor• March 2023 •Grandview Odor Control Project 2023• City of Twin Falls Scope of Work• 2 Assumptions Y Consultant assumes a Notice to Proceed date by April 2013. r Project duration will be 6 months, therefore it is assumed that there will be up to 6 progress payments/status reports. Task 2 — Data Collection and Sampling Objective The objective of this subtask is to establish baseline H2S concentrations in the sewer collection system at. The number of locations where sampling is performed is based on the desire to confirm representative sewer conditions exist before and during subsequent sampling and testing in Task 3. Activities Subtask 2.1 —Sampling Instrument and Testing Acquisition Consultant will procure up to six (6) rental pressure loggers, test and/or calibrate the pressure monitoring equipment used in Subtask 2.4. Subtask 2.2— Vapor Phase Sampling and Support For this task eight (8) App Tek International Oda Log loggers would be deployed by the City in select manholes/sampling locations throughout the project. Specific parameters and objectives of the vapor phase include establishing baseline and treated vapor phase H2S concentrations in the sewer collection system at up to eight locations. The number of locations where sampling is performed is based on previous locations. Vapor phase H2S is one of the most prevalent contributors to odor emissions and corrosion in wastewater collection system facilities.The loggers would use 0 to 1000 ppm long life sensors. Subtask 2.3—Liquid Phase Sampling and Support Consultant will support the City with recommendations for liquid phase sampling and laboratory analysis. At the selected monitoring locations, grab samples will be taken by City staff for all the liquid phase analyses. Liquid wastewater samples would be analyzed by an offsite laboratory. Subtask 2.4—Pressure Monitoring Consultant will support the City by operating pressure loggers during one (1)five day period to determine the area of effect of the vapor phase treatment system procured by the City in Take 4. City staff will assist with site access and installation of the pressure monitoring system.Two Consultant staff will provide onsite support over the course of five workdays. Task Deliverables None. Assumptions 1. City will install, maintain, download data and remove all odaloggers. Consor• March 2023•Grandview Odor Control Project 2023• City of Twin Falls Scope of Work• 3G:\PDX_BD\Clients\Twin Falls,ID\Grandview Odor Control 7-17\Contracting\TO 3 2023 Interim Solutions\SOW_G RAN DVIEW ODOR CONTROL PROJECT 2023.docx DRAFT 2. City will pay for all laboratory sampling and testing fees. 3. If required,the City will get permission for site access and coordinate with private land owners. 4. Detailed traffic control planning or hiring of outside traffic control resources such as "Roadwork Ahead" will not be required. In-road traffic control is assumed to be limited to the use of large safety cones and strategic parking of a work vehicle with flashers on. City will provide any needed traffic control. 5. Any required permitting fees will be paid directly by the CITY. Task 3 - Data Compilation, Analysis, Results, and Alternative Evaluation Objective To provide additional analysis to help guide the City's selection of alternative(s)to mitigate/manage odors and corrosion, Consultant will perform a progressive evaluation process as described in the following subtasks. Activities Subtask 3.1 —Liquid Phase Analysis In this subtask, Consultant will compile and process the data collected as part of Subtask 2.2 into a useable format for analysis and reporting purposes. Subtask 3.2— Vapor Phase Analysis In this subtask, Consultant will compile and process the data collected as part of Subtask 2.3 into a useable format for analysis and reporting purposes. Subtask 3.3—Pressure Monitoring Analysis In this subtask, Consultant will compile and process the data collected as part of Subtask 2.4 into a useable format for analysis and reporting purposes. Subtask 3.4—Data Compilation and Processing In this subtask, Consultant will compile and process the data collected in subtasks 3.1, 3.2 and 3.3 into a useable format for analysis and reporting purposes. Subtask 3.5—Alternatives Consideration In this subtask, Consultant will develop a list of liquid and vapor phase treatment alternatives for office (desktop)evaluation.These are anticipated to include the number,size,and type of treatment alternatives that the City may consider for permanent installation. Consor• March 2023 •Grandview Odor Control Project 2023• City of Twin Falls Scope of Work•4 Subtask 3.6—Technical Memorandum Consultant will develop a technical memorandum that documents the results of the sampling and monitoring program from Task 2, conclusions based on these results, alternatives considered in Subtask 3.5, recommendations, and project next steps. Subtask 3.7—Summary Presentation to City Consultant will develop a visual overview presentation of the subtask 3.6 technical memorandum and present to the City's desired presentation attendees. Task Deliverables 1. Electronic file (PDF)of subtask 3.6 summary technical memorandum. 2. Electronic file (PDF)of subtask 3.7 presentation. Task 4 - Interim Vapor Phase System Support Objective To provide the City with trailer vapor phase system bid documents for procuring a vapor phase treatment system and startup assistance. Activities Subtask 4.1 —Design Kickoff Meeting Conduct a Design Kickoff Meeting with City staff to review scope, schedule, budget and needed modifications to these items due to City selection of preferred mitigation option(s). Subtask 4.2—30% Design The purpose of this task is to use the results of the previous studies and tasks to develop a 30%design that further defines the work. The 30%design will start the transition of the project concepts from into formal design and trailer mounted dry carbon scrubber system procurement information to facilitate more detailed City and Consultant coordination and review. 30% Design Development will include the following Draft items: • Trailer mounted dry carbon scrubber system vapor phase treatment system mechanical and electrical requirements. • Division 0 (front-end specifications) • Opinion of probable cost for work • Updated design schedule The 30%design plans and specifications will be submitted to the City for review and comment. Consultant will attend a meeting with the City to review the 30%design package. Consor• March 2023•Grandview Odor Control Project 2023• City of Twin Falls Scope of Work• 5G:\PDX_BD\Clients\Twin Falls,ID\Grandview Odor Control 7-17\Contracting\TO 3 2023 Interim Solutions\SOW_G RAN DVIEW ODOR CONTROL PROJECT 2023.docx DRAFT Subtask 4.3—90%Design Package Consultant will develop a 90%equipment procurement design package based on the comments from the 30% Design. The 90% design package will include updates to the 30%design items from subtask 4.2 plus. The 90% Design Package is assumed to be nearly complete and only missing minor City review comments and minor changes. The 90%design plans and specifications will be submitted to the City for final review and comments. Consultant will attend a meeting with the City to present and discuss the 90% design package. Subtask 4.4—100%Construction Documents Consultant will finalize the 100% Construction Document package based on the comments received from Subtask 4.3 and provide an updated opinion of probable cost. Consultant will submit a final stamped permit set that will be sent to the City for final review and approval. Only very minor changes, if any, are anticipated with this submittal. Task 4.5—Services During Construction Under this task, engineering support services will be provided to the City during construction and startup of the of the Project. These services will be provided from the Bid Advertisement until the final acceptance of the project. Consultant will assist the City during construction, startup, data analysis, and will provide the following services: • Pre-Bid Meeting-Attend online pre-bid meeting. • Bid Clarifications and Questions-Answer questions during the bid period. • Addenda -Assist the CITY in creating any required addenda during the bid period. • Pre-Con Meeting-Attend online pre-con meeting. • Submittal Reviews - Review technical submittals and send submittal review forms (marked for acceptance, resubmit, or rejected) for conformance with project documents; up to two (2) submittals are included. Consultant will maintain an up-to-date submittal log. • System Startup — Consultant will verify that tests, equipment, and systems start-ups and operating and maintenance training are conducted in the presence of appropriate City personnel, and that Contractor maintains adequate records thereof. Startup is assumed to be over one (1) 8-hour man-day. • Operational Support -Consultant will conduct periodic operation support remotely with design team staff as requested by the City or as warranted by the progression of work. For developing this scope of work, 25-hours of support has been included for this support. • Data Analysis - Consultant will analyze vapor phase odalogger data over three instances from task 2.3 while vapor phase system is online. Task Deliverables 1. One electronic PDF copy of the 30%design package. Consor• March 2023 •Grandview Odor Control Project 2023• City of Twin Falls Scope of Work•6 2. One electronic PDF copy of the 90%design package. 3. One electronic PDF copy of the 100%construction documents. One iteration for minor comments assumed. Assumptions 1. Consultant will utilize the Idaho Standards for Public Works Construction (ISPWC) and City supplements to prepare the Construction Documents. ISPWC technical specifications will be referenced and not reproduced in the specification package. Supplemental technical specifications will be developed as required. 2. CITY legal staff will review the Division 0—Front-end documents. 3. Plans will be half size (11-inch x 17-inch). 4. Any required permitting fees will be paid directly by the CITY. 5. Land acquisition and easement acquisition support is not included. 6. This scope of work is based on the following assumptions regarding the Contract Documents: a. The Work will be performed by a single general contractor who will furnish all equipment, materials, and labor necessary to construct the project. b. Lump sum bid with award to the lowest responsive, responsible bidder. 7. City will produce and distribute bid documents from electronic PDFs prepared by Consultant. 8. Consultant will produce any required addenda during the bid period and City will distribute to bidders. 9. Consultant will review bids and recommend the apparent low bidder. Consultant is not required at the bid opening. 10. City will execute the contract with the selected Construction Contractor and provide all administrative requirements to execute the contract(e.g. legal review, sign contract forms). Budget Payment will be made at the Billing rates for personnel working directly on the project,which will be made at the current Consultant's Hourly Rates, plus Direct Expenses incurred. Subconsultants, when required by the Consultant,will be charged at actual costs plus a 10 percent fee to cover administration and overhead. Direct expenses will be paid at the rates shown in the table below. Budget requirements for construction support are dependent on a number of factors outside of Consor's control (construction duration, unforeseen conditions, etc..). Therefore, the work provided in this Task Order will be billed on a time and materials basis. The overall budget is an estimate only. The estimated breakdown for this work is outlined in Table 1. Consor will manage the work identified in this Task Order to the aggregate budget amount,which shall not be exceeded without prior written authorization from the City. When any budget has been increased or follow-on work contracted, Consor's excess costs expended Consor• March 2023•Grandview Odor Control Project 2023• City of Twin Falls Scope of Work• 7G:\PDX_BD\Clients\Twin Falls,ID\Grandview Odor Control 7-17\Contracting\TO 3 2023 Interim Solutions\SOW_G RAN DVIEW ODOR CONTROL PROJECT 2023.docx DRAFT prior to such an increase will be allowable to the same extent as if such costs had been incurred after the approved increase. Table 1 Total Project Fee Item Total Fee Task 1: Project Management $14,610 Task 2: Data Collection Sampling $44,621 Task 3: Data Compilation,Analysis, Results, and Alternative Evaluation $51,964 Task 4: Interim Vapor Phase System Support $37,211 Project Total $148,406 Direct Expenses Expenses incurred in-house that are directly attributable to the project will be invoiced at actual cost.These expenses include the following. Computer Aided Design and Drafting $18.00/hour GIS and Hydraulic Modeling $10.00/hour Mileage Current IRS Rate Postage and Delivery Services At Cost Printing and Reproduction At Cost Travel, Lodging and Subsistence At Cost Project Schedule This phase of work is assumed to be completed within 6 months of Notice to Proceed at the end of the City's fiscal year. Consultant will make every effort to complete the work in a timely manner; however, it is agreed that Consultant cannot be responsible for delays occasioned by factors beyond its control, nor by factors that could not reasonably have been foreseen at the time this Task Order was executed. Consor• March 2023 •Grandview Odor Control Project 2023• City of Twin Falls Scope of Work•8 f n m JI VT LT N N N N N u?N VN VN VN-N N u^ UT VN VN VN N N N C U U t5 n 3 N 4 ^N aRN VFN u^ NNNN�RN VAN V'NNN�A N - d vim�c'vi a Y - F E a a � c 0 c E a ° N = C tf H w W O o W �aa V Q U Y 0 W g O O � o O z o > W d � � � � N N t° n� N � OJ 9 m m � 2 :- �j •--�CJ .r. M^ Vt N _ C � u C7 � c u 8 m c W � c v c c a a` - a a a a - 0 0 0 0 N N - ti N M O _ 7 � E 9 d = C - N C Q C rC - C - Q O - � a ° u .o E e1 e1 N T Q N r. . . . M eq N M .V.�D . Q .-. N . . V. V.V. V. V. V.V. V. - � ev ev ri ri �rri rri rri rri ni rri m H s s��i v v i� � �n� a O�2 n n r co so DRAFT Grandview Sewer Odor Project Summary 2022 Technical Memorandum Date: March 30, 2023 Project: N 1721221 D.00 To: Nathan Erickson City of Twin Falls From: Mark Cummings, PE Consor Re: Twin Falls Grandview Sewer Odor Project Summary Report 2022 Introduction The Grandview Trunkline(Trunkline)is a major part of the City of Twin Falls'(City)sewage collection system. The Grandview Trunkline stretches over 5 miles from the canyon edge along Canyon Rim Road, Grandview Drive, Filer Avenue, cross-country past the County West building, down into Rock Creek and south along Washington Street South. Historically, portions of the sewer collection system have had citizen complaints due to odor related issue.Additionally,the concrete manholes,cast-iron frames and lids alongthe trunkline are also in in varying states of accelerated decay due to odor related microbially induced corrosion from to transformation of hydrogen sulfide to sulfuric acid. Previous `X'ork Because of odor and corrosion concerns, Consor (formerly known as Murraysmith) was tasked by the City to perform a series of studies focused on the Grandview Trunkline to better understand the potential causes of the sewer odor, magnitude of odor, areas of odor generation, and feasibility of different mitigation methods. Previous studies began investigating the whole Trunkline and identified point source permitted dischargers as the likely predominant sources of odor. Memoranda covering this previous work are provided in Appendix 1. 11leillo Content and Orgaiuzzation This Technical Memorandum is organized in the following sections and has been prepared to provide a general overview of the Trunkline, Odors, and Corrosion as well as a summary of work completed in 2022: 1. Grandview Sewer Trunkline—Provides an overview of the Grandview Trunkline portion of the sewer collection system. 2. Collection System Odors and Corrosion—Describes sewer collection system odor sources, generation, release, and associated corrosion. 3. 2022 Data Collection and Field Work—Describes the field work completed in 2022. 4. Results, Conclusions, and Next Steps—Summarizes the 2022 study results as well as recommendations and next steps for the project including additional field work,testing and design of engineered solutions N1721221D.00• March 2023 •City of Twin Falls Odor Project Summary 2022 • 1 1 - Grandview Sewer Trunkline The Grandview Trunkline generally flows from south to north and collects a large portion of the City's sewage collection system. For the purposes of this study, the Trunkline begins near the intersection of Washington Street and Highland Avenue, goes underneath Rock Creek in an inverted siphon, is pumped out of the Rock Creek Canyon, and then continues north to Canyon Rim Drive. The pipes in the Trunkline are 18- to 48-inch in diameter and there are approximately 100 manholes along the Trunkline sewer system.The Grandview Trunkline is shown in Figure 1 (provided at the end of this memorandum) and as a schematic in Figure 2 below. v a n, LL 3 z �a Y z Z <7.'fin i S ':.'3 E (+ aC � _ V m = Rock Creek —' v / U15la6 1:un i Figure 2 Grandview Sewer Trunkline-Schematic Rock Creek Litt Station The City's Rock Creek Lift Station is located one third of the way down the Trunkline.The lift station pumps sewage from an area down in the Rock Creek Drainage up to an area just west of County West buildings where flows can then proceed by gravity all the way to the Wastewater Treatment Plant (WWTP). The lift station has two separate wet wells.The lift station has seven 50-horsepower vertical coupled pumps each rated with a design capacity of 2,073 gallon per minute (gpm). Each pump has a pump on and off setpoint and the pumps are each outfitted with a variable frequency drive (VFD).The lift station has been noted in the past as a source of odor, particularly in the summer, and significant amounts of accumulated floatable grease must routinely be removed from the wet well by operations and maintenance staff to help reduce odors. Pernutted Dischargers There are several permitted wastewater dischargers in the southern portion of the Trunkline: Glanbia Nutritionals, Lamb Weston Inc., Aramark Uniform Services (formerly AmeriPride Linen and Apparel N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 2 Services), and West Rock(formerly Kapstone Container Corp).The discharge locations for each are shown in both Figures 1 and 2. Based on previous studies, the highest concentration of hydrogen sulfide is in the upstream area (i.e, southern end) of the Grandview Trunk which includes the majority of the permitted dischargers. Additional permitted dischargers exist in the City which discharge to other areas of the collection system (i.e. not into the Trunkline) and include the City of Kimberly, Chobani,and Clif Bar. 2 - Collection System Odors and Corrosion All sewer collection systems naturally create and contain odorous compounds. Various organic and inorganic compounds are known to cause odors in domestic wastewater collection systems. Mercaptans, ammonia compounds, and various volatile organic compounds are contributors to most odors found in collection systems. However, hydrogen sulfide is typically the predominant compound of concern due to its low odor threshold for human sense of smell. Odors are not the only problem caused by hydrogen sulfide in sewer. Hydrogen sulfide also leads to corrosion of cast iron manhole lids and frames and even manhole concrete. Bacteria convert hydrogen sulfide to sulfuric acid on the moist surfaces of the sewer system that results in corrosion. Hydrogen Sulfide Production acid Release The presence of hydrogen sulfide in municipal wastewater is principally the result of point source discharge (i.e.—permitted dischargers) and bacteriological reduction of sulfate in the presence of organic matter. The United States Environmental Protection Agency (EPA) defines point source pollution as any contaminant that enters an environment from an easily identified and confined place. For a sewer collection system,an example is a single discharger. Point sources can be a source of hydrogen sulfide due to their production,cleaning, and other processes at their facilities. Bacteria can also be a source of hydrogen sulfide through their metabolism.Sulfate-reducing bacteria grow in a "slime layer"that coats the sewer's wetted perimeter(Figure 3).These bacteria consume the available organic matter with the aid of oxygen in the most readily available form (in order of preference): 1. Elemental Oxygen 2. Nitrate Oxygen 3. Sulfate Oxygen Figure 3 Sulfide Generation ui Sewers Transfer of 142S to Pipe wall Oxidation to Sulfuric Acid NZS♦202 -- 14250; Air N2S Entering The Air Pipe Wall Sewage Di fusIon of SO4 and Nutrinds Production of Sulfide Diffusion of Sulfide into the Stream Reference: Gravity Sanitary Sewer Design and Construction,ASCE N1721221D.00 a March 2023 e City of Twin Falls Odor Project Summary 2022 a 3 Since nitrate is usually not available in wastewater, bacteria will consume sulfate oxygen after depleting elemental oxygen,leaving bi-sulfide ions to combine with hydrogen to form aqueous hydrogen sulfide. How quickly sulfide is produced by the slime layer and how it is then released to the gas phase (creating odor and corrosion problems)is impacted by a number of environmental factors as briefly described below. Note that while bacterial generation of hydrogen sulfide will occur in the Grandview Trunkline, the levels measured in the Trunkline are meaningfully above what would be typically expected from bacterial generation alone. Organic Matter & Sulfate Concentration Both organic matter and sulfate are prevalent in typical municipal wastewater. By using sulfate as an oxygen source,sulfate reducing bacteria are able to consume the readily available organic matter(food)to survive and grow.As such,the hydrogen sulfide production potential of a municipal wastewater typically increases proportional to the wastewater strength. Dissolved Oxygen As mentioned earlier, sewer bacteria prefer elemental oxygen when it's available. At dissolved oxygen (DO) concentrations above 0.5 to 1.0 milligrams per liter (mg/L) there is typically sufficient oxygen that sulfate reduction by bacteria is typically eliminated.At this DO concentration,the aerobic portion of the slime layer is able to grow and thus increases the distance which organic matter and sulfate must diffuse through the slime to reach the sulfate reducers in the interior anaerobic zone (see Figure 3 for reference). If organic matter and sulfate do happen to reach the anaerobic zone and produce sulfide, both the exterior aerobic slime layer and the DO rich wastewater stream will oxidize it,further decreasing the likelihood of aqueous hydrogen sulfide production. Wastewater gains oxygen in a collection system through re-aeration at the air to water interface. Turbulence resulting from high velocity flows,junctions,drops, hydraulic jumps and other places where the air and wastewater aggressively mix increases the reaeration rate. However,turbulent areas in a collection system do more than just increase the DO level. At these areas, the gaseous release of pre-existing hydrogen sulfide in the wastewater flow is accelerated as well. Detention Time The oxygen consumed by wastewater increases along with its detention time in sewers, force mains and non-aerated holding basins. This leads not only to decreased oxygen levels, but to increased availability of organic matter,further accelerating the oxygen depletion. Both conditions favor the activity of sulfate reducing organisms and the production of sulfides. Temperature As temperature increases, so does the activity of microbial life and the amount of hydrogen sulfide produced by sulfate reducing bacteria. In general, for every 10 degrees Celsius (18 degrees Fahrenheit) increase in temperature, the biological activity of bacteria, and of particular interest in odorous sewers, sulfate reducing bacteria, doubles. Typically, this results in markedly higher sulfide production in the summer than the winter. Additionally, higher temperatures decrease the solubility of the gases in solution and as a result the gaseous hydrogen sulfide more readily releases. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 4 Depth of Flow & Velocity As the depth of flow in a sewer increases, so does the surface area available to grow a sulfide producing slime layer. Flow rate, pipe diameter and slope are all factors that control the depth of flow and available surface area. Additionally, if the velocity in a sewer line is too low due to over sizing or inadequate slope, solids deposition in the system will occur. Deposited solids in a sewer system typically decay anaerobically, increasing the available slime layer surface area and sulfide production. The depth of flow for a given size pipe determines the cross-sectional area of the flow, its water surface area and therefore has an impact on the release of hydrogen sulfide. In general, the higher the ratio of water surface area to cross sectional area,the more readily hydrogen sulfide is released to the atmosphere. Velocity and/or turbulence in a wastewater flow,as mentioned earlier, also increases the gas transfer from the wastewater to the air above it. As such, turbulent areas in a collection system will simultaneously release dissolved hydrogen sulfide and capture oxygen from the air. pH Sulfate reducing bacteria can survive in a hydrogen potential (pH) range of 5.5 to 9.0. Since municipal wastewater typically is within this range, the pH of the wastewater does not have a significant impact on the production of aqueous hydrogen sulfide. However, depending on the pH of the wastewater, the form of sulfide it contains can vary dramatically. Since only the unionized form of sulfide (H2S) can be released from the wastewater solution into the air/gas phase, pH plays a significant role in collection system odor and corrosion. At a pH of 7,the ionized sulfides (HS-and S-) and unionized aqueous hydrogen sulfide(H2S) are essentially equal (Figure 4). At higher and lower pH, however these proportions quickly change with lower pH shifting to more aqueous hydrogen sulfide and thereby increasing the rate of hydrogen sulfide transfer to the gas phase. Figure 4 pH effect of Wastewater on Sulfide Species Present Reference: Gravity Sanitary Sewer Design and Construction,ASCE 120 W G 100 N W 80 J 0 80 --il— i H2S %HS"&S" p 40 v 20 ; W a 0 0 1 0 14 7.1 pH OF WASTEWATER N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 9 5 Odor Complauits Summary The City of Twin Falls has an informed community and many of the members have voiced their opinions and observations about the City's collection system odor.The City has an odor reporting tool on its website in the link below.This has provided valuable information on the extent, timing and type of odors present. Figure 5 shows the City's "Odor Wheel"which helps citizens identify odors based on general descriptors at the center of the wheel and more specific characters listed towards the wheel rim. The following Table 1 is a summary of the most common complaints of neighbors and members of the community in 2022. In 2022, a local news organization also reported on the odor complaints along the Trunkline made by residents specifically near Canyon Rim Road. https://www.tfid.org/FormCenter/City-Administration-2/Report-an-Odor-in-the-City-of-Twin-Falls-48 Figtire D- City' Odor«'heel Floral,perfume,fruits, Yeasty,sour milk, almonds,herbal, vinegar,sour chloroform 11 loom Rotten vegetable, `�- marshy,swampy, Decayed,rotten meat 000, skunk,rotten eggs �11'4 Fragrant/ Pungent/ 7o� -. I Soapy,chlorinous, Medicinal phenolic,alcohol, , , a � � disinfectant,bleach racal AMMOF Rubbery,plastic,glue, Pine/ Musty/ gasoline,moth balls, Lemon Moldy shoe polish,car exhaust, cleaning fluid,creosote, shy,urge,am grease,oil,paint, l tar,varnish,vinyl Pine,eucalyptus, Earthy,musty,moldy, minty,lemon, ashes,chalk,grassy, camphor,tea leaves mushroom,musky, smokey,stale,woody N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 6 Table 1 Examples of Odoi Complauits Example Odor Complaints "Sewer odor this morning on way to work,along Park View by park."5/18/22 "Good morning. I wanted to report the odors on Canyon Rim Road this Morning.They were bad as they were in May."6/28/22 "Had a little bit of stink today."7/8/22 "It was very pungent. Had to bring the Sunday Lunch from the porch into the house."7/3/22 "There were significant odors on Saturday and Sunday Morning,around 6:30 AM both mornings.They are returning more frequently."7/9/22 and 7/10/22 "An update this morning, I got up to go to work, there was a lot of odor around the house, had to shut all the windows, left for work and when I came home this evening the odor was still here, don't know what it was like during the day but a 6 o'clock it was very pungent."7/11/22 "1) Driving to work on Addison smelled like dead animal north of the Sugar factory. 2) 12:55 pm, smell on Grandview is horrendous 3)VERY STRONG -Odor caused nausea 4) On Columbia, Canyon Rim Road and Grand View.Absolutely terrible. 8:00 PM 5) 1 left for work this morning the outside smelt and the inside of my house mountain normal.Coming home at noon to odor inside the house was horrific,the outside was not as bad as the inside. Coming home from work this evening the outside is very pungent smells of raw sewage more than that usual chemical eye burning smell. 6)This is ongoing,and our people are continuing to get sick. It is not just one day or one time."8/30/22 "The sewer odor on Canyon Rim Road is bad." 10/5/22 3 - 2022 Data Collection and Field Work 2022 Stud- Goal Based on the past studies identifying the need to reduce hydrogen sulfide from point source permitted dischargers, City officials in combination with a permitted discharger,set the study goal to reduce levels of soluble hydrogen sulfide in the discharger point of compliance to a target goal of 0.5 parts per million (ppm). This section of the memo provides a detailed analysis of the 2022 work completed including hydrogen sulfide data collection, both liquid and vapor phases, and ferric chloride treatment feasibility. Permitted Discharger Soluble Hvdrogeii Sulfide Data Suininary To better define and quantify the odor generation potential from each permitted discharger, samples were collected and analyzed in 2022.Table 2 provides a summary of the soluble hydrogen sulfide measurements for the permitted dischargers along the Trunkline as well as other areas of the City sewer collection system. The soluble sulfide tests were done using grab samples which requires multiple grab sample tests to see patterns.That is why the Minimum, Maximum, Median, Mean and Standard Deviation are presented.The table shows that multiple permitted dischargers (F, G, H, and 1) discharge higher levels of soluble hydrogen sulfide more consistently. The 2022 average flow from each discharger is shown in the table. Dischargers with high flow and high concentration have a larger impact on the hydrogen sulfide in the collection system and associated odors. H, F, I and E have the largest impact on the hydrogen sulfide load to the City's overall sewer collection system. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 9 7 Table 2 Liquid Sulfur Testing Results . December per day tests ®®®® A 0.14 9 0.05 0.20 0.05 0.09 0.706 B 0.0042 6 0.02 0.20 0.05 0.08 C 0.0049 20 0.10 2.00 0.58 0.67 0.49 D 0.074 21 0.05 1.05 0.25 0.40 0.32 E 0.22 20 0.05 1.35 0.20 0.36 0.37 F 1.4 19 0.05 1.90 0.25 0.52 0.55 G' 0.021 7 0.10 2.25 0.12 0.73 0.89 23 0.10 11.40 0.60 1.98 2.62 H 1.8 22 0.01 12.80 0.20 2.38 3.89 1 0.63 22 0.05 19.00 0.53 2.33 4.60 Note*:One outlier datapoint removed from analysis. Ferric Chloride Pilot Information Chemical treatment of the Trunkline with ferric chloride will reduce the concentration of odorous hydrogen sulfide and provide a level of protection from corrosive conditions in the sewer. Pilot chemical treatment using ferric chloride was previously recommended in the Trunkline and work in 2022 included a long-term pilot to assess the effectiveness of the process. For long-term treatment, the amount and location of ferric chloride injected into the Trunkline should be optimized and hydrogen sulfide monitored to ensure that the correct dose is used. Ferric Chloride (FeC13) is an iron salt which, in the presence of hydrogen sulfide (HzS) in solution, produces a chemical iron-sulfur precipitate that permanently removes the sulfur from solution. This effectively eliminates future odorous and corrosive sulfur compounds from being produced. Ferric chloride is commonly used in wastewater to remove phosphorus from wastewater. The dosage of ferric chloride is dependent on water chemistry and sulfide(S=-)concentration and will produce a sludge(>_3 pounds sludge per pound sulfide)that will travel through the collection system.The theoretical dose of ferric chloride is 1.2 pounds(lb) iron (Fe31) per lb hydrogen sulfide(HzS)with practical dose rates anywhere from 1.5 to 4 lb iron (Fe31) per lb hydrogen sulfide (HzS) depending on the application and water chemistry. Optimum pH for ferric chloride treatment is around 8, which is similar to the pH in the City's sewer system. The application of ferric chloride also lowers pH,which can increase the soluble hydrogen sulfide that volatilizes in the collection system. Based on previous memorandums (TM-Ferric 2021 Pilot included in Appendix 1), ferric chloride was able reduce sulfide concentrations. Based on testing, 50 mg/L at the permitted discharger wastewater connection, was considered the minimum effective ferric chloride dose solution. The pilot test began on June 1, 2022, and ran until January 3, 2023. Ferric Chloride (38 percent strength) was supplied in chemical totes and was pumped directly into the waste stream. Photos of the pumping system are presented in Figures 6, 7 and 8.The dose rate varied from 11 gallons per day (gpd)to 104 gpd and is shown graphically in Figure 9.The previously recommended 50 mg/L dose for the average discharge is approximately 75 gpd. Many times, during the pilot test unexpected shutdowns and restarting of the ferric compound feed occurred. For example, the metering pump lost its siphon which caused the pilot system to stop applying ferric chloride to the sewer system. Incidents like this help to understand some of the sudden spikes and drops in hydrogen sulfide levels documented later in this memorandum. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 9 8 As a result of the ferric dosing, the wastewater treatment plant did experience negative impacts to the Ultraviolet Disinfection system due to bulb fouling and future use of ferric chloride should be carefully considered and impacts holistically determined within the whole sewer collection system and the wastewater treatment plant. Figure 6 Ferric Chloride Pilot System Photo 1 Figure 7 Ferric Chloride Pilot System Photo 2 Figure 8 Ferric Chloride Pilot System Photo 3 FERRIC CHLORIDE 38.42°/, Vol •..�. '"�" �7/MerMMilarr UNCs2• ®ww ...•eu ZJ N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 9 9 Vapor Please Hydrogen Sulfide To help quantify the effects of the addition of ferric chloride into the sewer system on the sewer headspace hydrogen sulfide concentration additional Vapor phase testing was set up. App Tek International Acrulog hydrogen sulfide loggers (Odaloggers) were placed in the air-filled headspace of manholes along the Trunkline to measure concentrations of hydrogen sulfide, see Figure 9 to 17 presented at the end of this memorandum. Odaloggers were placed in the manholes and were recording prior to the pilot,throughout the pilot and at least for one week after the pilot concluded. The graphs (figures) of Odalogger data, are presented at the end of this memo. The Odaloggers were placed in the following collection system manholes(upstream to downstream).The location of each manhole is shown on Figure 1: 1. C5-34 2. C5-160 3. C5-32—Public Works Yard Manhole 4. C5-3 5. C4-7—Rock Creek Trail Above UASB Discharge 6. C4-4—Rock Creek Trail Below UASB Discharge 7. B4-4 8. B1-47—Canyon Rim Interpretation of data The graphs shown in Figure 9 to 17 show the hydrogen su Ifide concentration in the headspace of the gravity sewer system from April 2022 to December 2022 with a total of eight sites. Four of these had meters that can reliably read to 1,000 ppm. The other four sites had meters that read to 200 ppm. Meter maximum capability was matched to site conditions seen during previous data collection periods. There are several occurrences of highly variable concentration. Several times during the study, the odaloggers had to be removed for maintenance which typically requires 2 or 3 days without data. To understand the impact of the ferric chloride pilot,data was collected before, during, and after the pilot. Some of the key information in the graphs are as follow: Blue represents the levels of hydrogen sulfide recorded by the odalogger in ppm. y Green represents the ferric chloride dose in gpd. Vertical black and yellow lines show start up and shutdown of Lamb Weston during seasonal operation shutdowns. Site C5-34 is located in the very far upstream reach of the Trunkline and upstream of all industrial dischargers and the ferric chloride pilot. It acted as a control during the study. As seen in Figure 10, lower levels of hydrogen sulfide were recorded for the majority of the study.Concentrations of 0 to 10 ppm were consistently recorded. Site C5-160 is located in the very far upstream reach of the Trunkline and upstream of all industrial dischargers.The level of hydrogen sulfide varies diurnally (i.e. as flow rises and falls through the day).This is likely created in the sewer by bacteria, also known as "in situ", as naturally occurring non-point source hydrogen sulfide. Concentrations are also higher during periods of higher air temperature which is consistent with bacterial induced hydrogen sulfide formation through their metabolism. There is an high concentration anomaly around the end of October with 268 ppm. The reason for this short duration anomaly is not known.This site acted as a control upstream of the pilot and industrial dischargers. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 10 Site C5-32 is just downstream of the first industrial discharger and ferric chloride pilot. This location has exhibited high variation in hydrogen sulfide and the highest average concentration. The varying industrial activities likely contribute to such high levels and variable hydrogen sulfide. By looking at Figure it we can see a steady trend of high levels however when ferric chloride doses were implemented the level of hydrogen sulfide decreased. Site C5-3, Site C4-7, Site C4-4, Site 134-4, and Site B1-47 show a reduction in the concertation of hydrogen sulfide in the air of the sewer collection system when comparison upstream to downstream locations.This is due to decreasing liquid hydrogen sulfide concentration due to wastewater entering the trunkline from side sewers. There is also variation due to air flow dynamics and some areas of the system have fresh air being pulled into the collection system due to the movement of the water in the pipes. Site B1-47 is at the far downstream end of the Trunkline. This site has the lowest hydrogen sulfide concentration due to dilution of the wastewater in the collection system. However, the concentration of hydrogen sulfide is still high for a collection system and this is the area the has the most complaints logged in the City.Trends in hydrogen sulfide concentration from upstream are visible in this site as well. 4 — Results, Conclusions, and Next Steps The results of the 2022 ferric chloride pilot are described below. Further below is a discussion on the conclusions for chemical treatment and the next steps for this project. Ferric Chloride Pilot Results Comparing the concentration of hydrogen sulfide at the locations before, during, and after the chemical feed shows that ferric chloride addition can be effective in reducing hydrogen sulfide concentrations in the Trunkline. However,the complex relationship of monitoring highly variable hydrogen sulfide concentration in both liquid and vapor phases, associated feed rate/dosing adjustments and location(s) of the chemical treatment would make the system complex and would need to be optimized for concentration and flow. However,the odor problem for the Trunkline is not as simple as injecting large amounts of ferric chloride. The key is a balance between monitoring, prevention, and treatment.The Trunkline sewer system has a big impact on the neighbors and industrial sites. It is in the best interest of all parties to share information and develop a comprehensive plan and solution, so the effectiveness of treatment can be achieved to its maximum potential. Conclusion — Chemical Treatment Chemical treatment at industrial dischargers or within the collection system is a possibility. Use of chemicals, including ferric chloride, by industrial dischargers to control their hydrogen sulfide discharge to the collection system may be a viable solution. However, it is expensive due to ongoing costs of chemical and operation and maintenance needs. Other possibilities that have been successfully used by collection system operations in the City collection system include routine slug load dosing of caustic soda (sodium hydroxide). Caustic soda is very basic and kills the slime layer growing on the inside of the sewer system piping. Caustic soda slug loading will not help with point source hydrogen sulfide from permitted dischargers.Overall,the City should holistically consider chemicals used by industrial dischargers and within collection system due to the impacts to the collection system and the WWTP. Overall,the use of chemicals can have unintended and deleterious effects on the system (e.g. ferric chloride fouling of the WWTP UV disinfection system bulbs), are complicated by multiple dischargers, and the highly variable sulfide concentration. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 11 Prioritization of Next Steps The City has prioritized its next steps, as discussed below, to improve conditions along the Grandview Trunkline and decrease the amount of hydrogen sulfide in the sewer collection system. The prioritization is seeking to strike the right balance between urgency, importance, difficulty, size, cost, and complexity. 1. Point Source Management 2. Local Limit 3. Vapor Phase Treatment 4. Engineering, Design and Construction Next Steps 5. Rehabilitation of Manholes Next Step — Pouit Source Management The City plans to continue to work with point sources to identify sources of hydrogen sulfide and methods to resolve these. Some industries have already switched chemicals used or are making changes to their systems to address and control sulfide contributions to the City's collection system. Next Step — Local Limit Local limits address the specific needs and concerns of a municipality and its wastewater treatment plant and collection system, sludge, and its receiving waters. The local limit process determination includes evaluation of facility capabilities and establishment of local limits to protect from receiving waste that passes through or interferes with operations (including sludge management). Local limits are intended to protect the treatment and collection system, receiving waters, workers' health and safety, and sludge disposal practices. Local limits are site-specific and can be numeric or narrative effluent discharge limits, including best management practices. Local limits are in effect source control.The City and industrial dischargers should prepare for this type of effort and work hand in hand as an opportunity to improve the conditions in and around the City. This includes sharing planning efforts, operational information, manpower, sampling and reports. If local limits are set, many discharge limitations and monitoring requirements will be defined: testing, sampling, reporting, discharge limits, upset conditions, and enforcement actions. Additionally, concentration and/or mass limits could be set with penalties for dischargers not meeting permit conditions. Completing a local limit for hydrogen sulfide will require additional investigation and data collection on industrial dischargers.This includes real time liquid soluble hydrogen sulfide concentration data acquisition, odaloggers placed at each industrial discharger point of compliance,continued collection system odalogger use. Next Step — Vapor Please Treatment Vapor phase treatment controls and treats the air in the sewer system before it is released from the collection system. It is an effective means of addressing hydrogen sulfide related odor and corrosion problems. The ease at which gaseous hydrogen sulfide is converted to sulfuric acid in a municipal sewer collection system and the susceptible nature of the collection system to corrosion means that containment- only with airtight manholes lids as a solution should not be considered.Containment additionally will make corrosion of the sewer even worse due to increased hydrogen sulfide concentration and corrosion potential. However, controlled discharge of the hydrogen sulfide in the gaseous phase combined with air hand Iing/treatment techniques can be effective. Wet scrubbers and dry scrubbers (adsorptive processes) are the two most common air treatment techniques.Vapor phase treatment is anticipated to be beneficial N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 12 to address localized odor problems and multiple installations would be recommended. The Trunkline is physically separated into three headspace areas due to the siphon under Rock Creek and the Rock Creek Lift Station, and each will need one or more vapor phase treatment system(s) to holistically treat the Trunkline headspace. From previous analysis, five scrubbers would likely be needed to treat the whole Trunkline. Additionally, due to the highly variable hydrogen sulfide loading, biological wet scrubbers are not expected to work well in the Trunkline because the microorganisms that transform the hydrogen sulfide to other compounds go between periods of starvation and feasting and cannot reliably maintain the biomass to treat the hydrogen sulfide load. Carbon dry scrubbers can be used though.Carbon dry scrubber odor control systems are designed to treat hydrogen sulfide and other odorous compounds found in municipal wastewater collection systems and treatment processes. The carbon adsorber odor control system consists of an exhaust fan, ductwork, vessel with activated carbon and a control panel. After entering the vessel,the foul air from the collection system flows through a densely packed bed of activated carbon. The odorous compounds are removed from the airstream through an adsorption process where they adhere to the activated carbon media pores. A subsequent chemisorption process transforms hydrogen sulfide into sulfur. The adsorption process continues until the activated carbon pores are depleted.The cleaned air continues through the vessel and is discharged through the vessel outlet stack. The system would operate continuously. The control panel ensures proper control and operation of the system. The system will be designed to use a high hydrogen sulfide capacity pelletized carbon media for the removal of hydrogen sulfide from the odorous airstream. The City can approach vapor phase treatment as a short-term interim solution and a long-term solution. The short-term solution would consist of renting or purchasing a skid-or trailer-mounted system that can be placed where needed in the system. A rented skid mounted system would cost roughly $75,000 for a year rental and other installation related items(e.g.power drop,fencing,and ductwork).The length of time the carbon media lasts is dependent on the concentration of hydrogen sulfide treated. Purchasing a trailer mounted system would cost roughly $150,000. A permanent solution could cost as little as $450,000 construction cost for a single small system to be used in the upstream area of the trunkline and up to $1,250,000 each for a large system in the downstream area of the trunkline.These costs assume that a site is generally located next to the trunkline and ready for a municipal installation and does not include land acquisition, extensive piping/ducting, or running utilities to the site. Carbon media would also need to be purchased on a regular and ongoing basis to replace spent media.The City should confirm the number of systems to be installed during predesign effort but a minimum of three are needed due to the three independent sewer air spaces. Next Step — Engineering, Design and Construction Next Steps Engineering, Design and Construction Next Steps includes multiple tasks in two phases to further define the design, site selection and survey, assist with procurement of a trailer mounted scrubber, write a preliminary engineering report, and draft contract documents for a construction project. To accomplish this work, this scope of work (SOW) includes two phases: Preliminary Design and Final Design. Preliminary Design phase includes collection of system sampling (liquid and vapor phase), procurement of a trailer mounted carbon scrubber system, development of solution alternatives and associated capital and life cycle costs.This phase will be completed by September 2023. The Final Design phase includes design of the selected scrubber alternative and manhole rehabilitation.This phase will begin in October 2023. The Phase 1 engineering fee is estimated at approximately $150,000. The Phase 2 engineering fee is estimated at$350,000. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 13 Next Step — ReliablEtation of'Manholes City staff have noted the advanced state of corrosion, deterioration and extremely poor condition of the concrete manholes and cast-iron components throughout the Trunkline.There are 103 manholes along the Grandview Trunkline with approximately 890 total vertical feet (rim to invert). Most of the manholes are concrete in various states of corrosion and degradation. There are some manholes that are lined with a precast liner, are polymer concrete, and have other corrosion resistant materials (e.g. polymer lids rather than cast iron).The cast iron frame and covers are rusting, corroding and in various states of decay. Some of the manholes have had composite frame and covers installed due to corrosion of the original cast iron. The City should begin a manhole rehabilitation program including manhole condition assessment with field confirmation of conditions and prioritization of repair, rehabilitation, and replacement of manholes. In 2021, Consor completed a desktop study to generate conceptual costs estimates to both conventionally replace and rehabilitate the Trunkline to make it more resistant to the existing corrosion conditions. The City should also consider any replacements be completed with corrosion resistant manhole materials such as including polymer manholes, composite frames, and lids. Rehabilitation of concrete manholes could include a mix of spray on liner application, polymer manhole inserts,cured-in-place manhole and composite frame and lids. The construction cost to repair and replace all the manholes in the Trunkline is between $2,000,000 and$3,000,000.These costs should be confirmed and updated after fieldwork and updated for the current construction climate. The City should also confirm that all pipe in the trunkline is plastic (e.g. PVC) pipe. If any concrete pipe exists, it is likely also in deteriorate condition and should be replaced as well. N1721221D.00 • March 2023 • City of Twin Falls Odor Project Summary 2022 • 14 r K c 41 W7 �4" j fit_ ,7 AID 1 Y • {€e fill A «i. vM 'f f� --� `rr�.� i�•per, '4•_ ��r i' G _ Ad . *V,y ., Legend U Rock Creek Lift Station ger Location Grandview Trunkline Figure 1 Logger and Industrial Discharge Main Locations Locations •._. 1 1 Figure 9 - Ferric Chloride Dose may\ i titi\ v 0 0 a 0 t U v LL �ti I ,�O may\ tiry b\ tiry \r O\ 0 CD 00 � CD CD CD 0 (pdS)asoa apuoly:):)laaaj Figure 10 - C5-34 tw C O � N \v O � U v 7 C v O S ti~ M O� \b tilb V,O 9\ h a\ O O O O O O CD O O O CD O Ol cc r- z U1 dt M rl (wdd) uoijejlua:)uo'apijlnS uaSoapAH Figure 11 - C5-160 c 0 Y l� L C V C U O�ti OJ � c ~ 01 An O i S I O l� c-I i u1 V ti~ ,VO 0\ h 0 0 0 0 0 0 0 0 0 0 O 0) 00 l0 Ln d' M N -4 (wdd) uopealua:)uo:)api;lnS uaSoapAH Figure 12 - C5-32 (pdS)asoQ apuoly:):)ujaj 0 0 CD 000 LCD DD v 0 'Ah\� ti o a C i O L m C U O U = U i tiry O \ry ti0 I � tiry N m Ln U yam\ h a 0 0 0 0 0 0 0 0 0 0 0 O 01 00 �D Ln d' Cn N �--i (wdd)uoilealua:)uo:)ap!jlns uaBOJPAH Figure 13 - C5-3 (pdS)asoa apiaoly:):)uaaj 0 CD 0000 CD v 0 1'y _ h\ c 0 �o c c a fU � a t� e. a -C m c o o \ c o d v ~O m u 3 3 o E E S Ll J J I I I I OIV � m Ln U tiry W\ h of\ b\ 0 0 0 0 0 0 0 0 0 0 O 0) 00 l0 Ln M N .-I e-I (wdd)uoi;ejiva:)uo:)apgjns uaSoapAH Figure 14 - C4-7 (pdS)asoa apijoly:):)ijaaj 0CD 0 00 � v oN o c 0 N f0 L c C C c 0 a 0 v Y 72 0 .2 \ 0 a 0 0 1�O ° o ' ho\ m u 0 a c i m m I I I I d' U do c\ tiry of\ d\ 0 0 0 0 0 0 0 0 0 0 o m ao Ln v en C14 .� (wdd) uoilealua:)uo:)api;lnS UOSOJPAH Figure 15 - C4-4 (pdB)asoa apijoly:):)ijjaj Go v CDti CD ti ,y\ ti c 0 c c c 3 m v a iIN O O O c O v N ti 000 U a I I I I U q\ P\ h \�\ - p 0 0 0 0 0 0 0 0 0 0 o m co n Ln m rq .� .r (wdd) uoijealua:)uo:)api;lnS uagoapAH Figure 16 - B4-4 (pdS)asoa apiaol4D:)ijjaj 0 0 CD CD 000 � v o rV�' \~ c 0 m co c c c a o a, a 0 IA v 'Y +0.� ^O� 0 c 0 m u o\� O u y E E S LL J m I I I I �O 1 m �O \y ,40 h\ \k h ,y0 \h\ 0� 0 0 0 0 0 0 0 0 0 0 0 O Ol 00 lD Ln en N e-1 r-I (wdd)uoijejlua:)uo:)api;lnS uaSojpAH Figure 17 - B1-47 (pdR)aso(i apiaoly:):)ujaj ti CCD CD v CD rq o \ ti 0 c c ti0 a 0 y a 7 � v a o c n 0 an u 3 3 o a E E S Ll J J o I I I I NN c-1 m tip, M� ya� O O O O O O O O O O O 01 00 Ln d m N .--i (wdd) uoiiejlua:)uo:)api;lnS uaSojpAH '>murraysmith Technical Memorandum Grandview Odor Control Study City of Twin Falls, Idaho fy 1 Date: March 15, 2018 1 Project: City of Twin Falls: Grandview Odor Control Study GF To: City of Twin Falls, Idaho From: Murraysmith Background Information Introduction The Grandview Trunkline is a major part of the City of Twin Falls' (City's) sewage collection system and has historically had citizen complaints due to odor. The concrete manholes, cast-iron frames and lids along the trunk are also in in varying states of decay due to corrosion. The Grandview Trunkline stretches over 5 miles from the canyon edge along Canyon Rim Road, Grandview Drive, Filer Avenue, cross-country past the County West building, down into Rock Creek and south along Washington Street. This study included collection system sampling, both liquid and vapor phase, to help delineate and quantify problems areas along the trunkline. This study is the first phase of a project to control odor and corrosion in the Grandview Trunkline. Subsequent phases will include additional sampling (if needed), development of solution alternatives and associated capital and life cycle costs, design of the selected alternative, and bidding and construction phase support. Collection System Odors and Corrosion All collections systems naturally create and contain odorous compounds. Various organic and inorganic compounds are known to cause odors in domestic wastewater collection systems. Mercaptans, ammonia compounds and various volatile organic compounds are contributors to most odors found in collection systems. However, hydrogen sulfide is typically the predominant compound of concern due to its low odor threshold and the associated corrosion from the conversion of hydrogen sulfide gas to sulfuric acid in the moist head space of gravity sewer lines. 17-2122 Page 1 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho Hydrogen Sulfide Production and Release The presence of hydrogen sulfide in municipal wastewater is principally the result of bacteriological reduction of sulfate in the presence of organic matter. Sulfate-reducing bacteria grow in a "slime layer"that coats the sewer's wetted perimeter(Figure 1).These bacteria consume the available organic matter with the aid of oxygen in the most readily available form (in order of preference): 1. Elemental Oxygen 2. Nitrate Oxygen 3. Sulfate Oxygen Figure 1 Sulfide Generation in Sewers Reference: Gravity Sanitary Sewer Design and Construction, ASCE Transfer of H2S to Pipe Wall Oxidation to Sulfuric Acid H2S + 202 — H2SO4 ti N Ci 67 ' C C i U Air H2S Entering The Airy Pipe Wall 5U� e Sewage r Diffusion of SOq and Nutrients o Production of Sulfide Diffusion of Sulfide into the Stream 8 Vwiabie"Aerobic"Zone �I N Since nitrate is usually not available in wastewater, bacteria will consume sulfate oxygen after depleting elemental oxygen, leaving bi-sulfide ions to combine with hydrogen to form aqueous hydrogen sulfide. How quickly sulfide is produced by the slime layer and how it is then released to the gas phase (creating odor and corrosion problems) is impacted by a number of environmental factors as briefly described below. 17-2122 Page 2 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.201&doa Organic Matter& Sulfate Concentration Both organic matter and sulfate are prevalent in typical municipal wastewater. By using sulfate as an oxygen source, sulfate reducing bacteria are able to consume the readily available organic matter (food) to survive and grow. As such, the hydrogen sulfide production potential of a municipal wastewater typically increases proportional to the wastewater strength. Dissolved Oxygen As mentioned earlier, sewer bacteria prefer elemental oxygen when it's available. At dissolved oxygen (DO) concentrations above 0.5 to 1.0 mg/L there is typically sufficient oxygen that sulfate reduction by bacteria is typically eliminated. At this DO concentration, the aerobic portion of the slime layer is able to grow and thus increases the distance which organic matter and sulfate must diffuse through the slime to reach the sulfate reducers in the interior anaerobic zone (see Figure 1 for reference). If organic matter and sulfate do happen to reach the anaerobic zone and produce sulfide, both the exterior aerobic slime layer and the DO rich wastewater stream will oxidize it, further decreasing the likelihood of aqueous hydrogen sulfide production. Wastewater gains oxygen in a collection system through re-aeration at the air to water interface. Turbulence resulting from high velocity flows,junctions, drops, hydraulic jumps and other places where the air and wastewater aggressively mix increases the reaeration rate. However, turbulent areas in a collection system do more than just increase the DO level. At these areas, the gaseous release of pre-existing hydrogen sulfide in the wastewater flow is accelerated as well. Detention Time The oxygen consumed by wastewater increases along with its detention time in sewers, force mains and non-aerated holding basins. This leads not only to decreased oxygen levels, but to increased availability of the organic matter, further accelerating the oxygen depletion. Both conditions favor the activity of sulfate reducing organisms and the production of sulfides. Temperature As temperature increases,so does the activity of microbial life and the amount of hydrogen sulfide produced by sulfate reducing bacteria. In general, for every 10 degrees Celsius increase in temperature, the biological activity of bacteria, and of particular interest odorous sewers, sulfate reducing bacteria, doubles. Typically, this results in markedly higher sulfide production in the summer than the winter. Additionally, higher temperatures decrease the solubility of the gases in solution and as a result the gaseous H2S more readily releases. Depth of Flow& Velocity As the depth of flow in a sewer increases, so does the surface area available to grow a sulfide producing slime layer. Flow rate, pipe diameter and slope are all factors that control the depth of 17-2122 Page 3 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview odor\Memo\TM-Fall 2017_3.14.201&doa flow and available surface area. Additionally, if the velocity in a sewer line is too low due to over sizing or inadequate slope, solids deposition in the system will occur. Deposited solids in a sewer system typically decay anaerobically, increasing the available slime layer surface area and sulfide production. The depth of flow for a given size pipe determines the cross-sectional area of the flow, its water surface area and therefore has an impact on the release of hydrogen sulfide. In general,the higher the ratio of water surface area to cross sectional area, the more readily hydrogen sulfide is released to the atmosphere. Velocity and/or turbulence in a wastewater flow, as mentioned earlier, also increases the gas transfer from the wastewater to the air above it. As such, turbulent areas in a collection system will simultaneously release dissolved hydrogen sulfide and capture oxygen from the air. pH Sulfate reducing bacteria can survive in a pH range of 5.5 to 9.0. Since, municipal wastewater typically is within this range, the pH of the wastewater does not have a significant impact on the production of aqueous hydrogen sulfide. However, depending on the pH of the wastewater, the form of sulfide it contains can vary dramatically. Since only the unionized form of sulfide (H2S) can be released from the wastewater solution, pH plays a significant role in collection system odor and corrosion. At a pH of 7, the ionized sulfides (HS- and S-) and unionized aqueous hydrogen sulfide (H2S) are essentially equal (Figure 2). At higher and lower pH, however these proportions quickly change with lower pH shifting to more aqueous hydrogen sulfide and thereby increasing the rate of hydrogen sulfide transfer to the gas phase. 17-2122 Page 4 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.201&doa Figure 2 pH effect of Wastewater on Sulfide Species Present Reference: Gravity Sanitary Sewer Design and Construction, ASCE 120 W G 100 N W 80 J 60 --it- %H2S %HS'8 S' p 40 v 20 ; W IL 0 0 1 0 14 7.1 pH OF WASTEWATER Grandview Trunkline The Grandview Trunkline generally flows from south to north and collects from a large portion of the City's sewage collection system. For the purposes of this study,the Grandview trunkline begins at manhole C5-160, near the intersection of Washington Street and Highland Avenue, and continues to manhole 61-28. The pipes in the trunkline are 18- to 48-inch in diameter and there are approximately one hundred manholes along the trunk. The Grandview Trunkline is shown in Figure 3 and as a schematic in Figure 4, both figures are at the end of the memorandum. The City does not routinely inspect or clean the trunkline because flows and velocity hare high enough that solids deposition has not historically been a problem. Rock Creek Lift Station The City's Rock Creek Lift Station is located one third of the way down the trunkline.The lift station pumps sewage from an area down in the Rock Creek Drainage up to an area just west of County West buildings where flows can then proceed by gravity all the way to the WWTP. The lift station has two separate wet wells.The lift station has seven 50-horsepower vertical coupled pumps each rated with a design capacity of 2,073 gallon per minute (gpm). Each pump has a pump on and off setpoint and the pumps are each outfitted with a variable frequency drive (VFD). The lift station has been noted in the past as a source of odor, particularly in the summer, and significant amounts of accumulated floatable grease must be removed from the wet well by operations and maintenance staff. In the first quarter of 2017, the average flow pumped by the lift station was 3,435 gpm (approximately 5 mgd). 17-2122 Page 5 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.2018.doa Industrial Wastewater Dischargers along the Grandview Trunkline There are four permitted wastewater dischargers in the southern portion of the Grandview Trunkline: Glanbia Foods Inc., Lamb Weston Inc., AmeriPride Linen and Apparel Services and Kapstone Container Corporation. Each of the industrial discharge permits is included in Appendix 1 and is summarized in Table 1 through 4 with actual 2017 quantities for comparison.The location of the industrial dischargers are also shown on Figure 3 and Figure 4. Glanbia Glanbia Foods is a dairy processing facility and discharges its wastewater to the collection system between Diamond and Washington Street (just north of Glanbia facility). The flow from Glanbia Food ultimately joins the Grandview Trunk at manhole CS-30. Glanbia does not have a pretreatment system but does have an equalization basin that it uses at times to keep within their discharge permit. The 2017 Glanbia wastewater had a high BODS concentration, TSS concentration, relatively high pH and at times high levels of fats/oils/grease (FOG). Glanbia's wastewater discharge represents approximately 13 percent of the BOD and 7 percent of the wastewater flow that the wastewater treatment plant (WWTP) treated on average through calendar year 2017. Table 1 Glanbia Foods, Inc. — Industrial Wastewater Discharge Permit and 2017 Data Summary Pollutant Permit Daily 2017 2017 Maximum 2017Average Min Max Flow(MGD1) 0.700 0.546 0.326 0.757 BOD5 (lb/day) 5,462 3,124 1,007 9,720 BOD5 (mg/L) NA 687 248 2115 TSS(lb/day) 1,858 989 110 2,397 TSS(mg/L) NA 215 29 585 FOG (mg/L) 200 67 23 209 pH 6.0to9.5 9.0 5.5 11.4 Note: 1. Million Gallons per Day Lamb Weston Inc. Lamb Weston Inc. is a food processor that has two discharge points to the Grandview Trunkline. The first discharge is at manhole C5-2 and does not have any pretreatment. The second discharge is at manhole C4-322 and has been pretreated of an upflow anaerobic sludge blanket pretreatment process with post-aeration. Lamb Weston's wastewater discharge represents 17-2122 Page 6 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.201&doa approximately 20 percent of the BOD and 35 percent of the wastewater flow that WWTP treated on average through calendar year 2017. Table 2 Lamb Weston Inc. — Industrial Wastewater Discharge Permit and 2017 Data Summary Permit Daily Pollutant Permit Daily Maximum Maximum 2017 Average 2017 2017 Days Clean-up Min Max Days Flow (MGD) 2.8 2.8 1.8 0.0 2.7 BOD5 (lb/day) 35,000 16,500 4,818 9 23,192 BOD5 (mg/L) NA HA 302 13 1,163 TSS (lb/day) 12,000 12,000 3,229 6 8,244 TSS(mg/L) NA NA 204 14 513 FOG (mg/L) 200 200 62 1 526 pH 6.0to9.5 6.0to9.5 7.1 6.7 8.3 AmeriPride Linen and Apparel Services AmeriPride Linen and Apparel Services discharges to the collection system near 5th Street West and 2nd Ave West, which is a considerable distance away from the Grandview Trunks. The flow from this discharger ultimately enters the Grandview Trunk at manhole 134-1. AmeriPride does utilize a dissolved air floatation thickener process to pretreat its wastewater prior to discharge. 17-2122 Page 7 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho 1:\130I_Projects\17\2122-Tvnn Falls Grandview odor\Memo\TM-Fall 2017_3.14.201&doa Table 3 AmeriPride Linen and Apparel Services — Industrial Wastewater Discharge Permit and 2017 Data Summary Pollutant D. Ma)dmurn 2017 Average 2017 2017 Min Max Flow(MGD) 0.150 0.079 0.0 0.148 BOD5 (lb/day) 500 187 51 741 B0 D5 (mg/L) NA 194 68 676 TSS (lb/day) 500 65 18 448 TSS(mg/L) NA 67 20 426 FOG (mg/L) 500 76 3 283 pH 6.0to9.5 7.8 6.8 9.8 KapStone Container Corporation KapStone Container Corporation discharges to the at Blake Street South upstream of the Grandview Trunkline and flow from this discharger ultimately joins the Grandview Trunkline at manhole C5-177. KapStone utilizes a beckart filter press to pretreat wastewater prior to discharge to predominately remove dye. Table 4 KapStone Container Corporation — Industrial Wastewater Discharge Permit and 2017 Data Summary Pollutant Permit D. ,.. 2017 2017 Min Max Flow(MGD) 0.130 0.004 0.0 0.013 BOD5 (lb/day) 984 16 0 72 BOD5 (mg/L) Na 487 16 2,445 TSS(lb/day) 960 7 0 50 TSS(mg/L) NA 176 5 1760 FOG (mg/L) 200 2.5 2.5 2.5 pH 6.0 to 9.0 7.6 7.2 8.2 WWTP Flow Data The City has provided 2018 calendar year influent data from the WWTP for this study and it is summarized in Table 5. 17-2122 Page 8 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho I';BCI—Projects\17\2122-Twin Falls Grandview 0dor\Memo\Tk4-Fa112017-3.14.2018.doa Table 5 2017 WWTP Influent Data Summary Cormtmjent Average Day Max Month Max Week Max Da Flow(MGD) 7.93 8.78 9.94 11.95 BOD5 (lb/day) 24,511 29,056 32,086 53,466 BOD5 (mg/L) 371 432 471 780 TSS (lb/day) 16,008 19,433 22,743 48,583 TSS(mg/L) 24 279 338 735 Temperature (°F) 61.2 76.3 77.3 80.2 pH 8.2 7.9to8.4 7.8to8.6 7.5to8.7 Vapor Phase Odor Monitoring Equipment and Methods Murraysmith used eight rented and one City-owned App Tek International OdaLog L2 loggers (odalogger) odor meters for this study. Murraysmith staff, with assistance from City staff, installed the flow meters and removed them at the end of the monitoring period. Murraysmith inspected the meters intermittently to check battery status, download the data, and confirm that the equipment was operating properly. The odalogger meters were installed on November 20, 2017 and removed on December 12, 2017. The locations where the odaloggers were placed is shown in Figure 3, at the end of this memorandum, and schematically on Figure 4. Vapor Phase Results Table 6 summarizes the data from the individual odaloggers which were suspended from manhole lids. The odaloggers monitor hydrogen sulfide (112S) gas concentration and temperature of the headspace in the collection system. Appendix 2 graphically shows the odalogger data. During the study, Lamb Weston shut down its operations from November 22 to November 27 for a seasonal shutdown.The shutdown started with a two-shift cleanup procedure.The change in the odalogger data caused by the shutdown is evident in the graphs. 17-2122 Page 9 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho I:'\BCI_Projects\17\2122-Twnn Falls Grandview 0dor\Memo\Tk4-Fall 2017_3.14.2018.doa Table 6 Vapor Phase OdaLogger Summary Site Manhole ID H2S . . LOW Average High LOW Average High SO C5-160 0.0 0.0 5 41.7 49.4 64.4 S1 C4-7 0.0 30.5 333 42.4 61.6 77.0 S2 C4-4 0.0 3.8 64 51.1 75.3 84.6 S3 B4-10 0.0 2.4 48 55.30 76.9 85.2 S4 64-5 0.0 3.6 150 60.2 66.0 76.1 S5 B3-13 0.0 20.2 154 58.1 68.6 78.2 S6 63-1 0.0 16.0 98 59 67.6 74.4 S7 B1-12 0.0 11.6 103 54.5 67.8 74.6 S8 B1-28 0.0 5.1 64 54.1 66.9 73.4 Note 1. Parts per million For comparison to the vapor phase monitoring results, range of H2S gas exposure are described below: • 0.00047 ppm: Human odor threshold is <10 ppm: Irritation of eyes, nose, throat and respiratory system • 10-50 ppm: Headache, dizziness, nausea, coughing, vomiting and difficulty breathing • 20 ppm: OSHA acceptable ceiling concentration • 50 ppm: OSHA acceptable maximum peak with a maximum duration of 10 minutes if no other exposure occurs during an 8-hour shift • 50-100 ppm: Eye injury can occur is At 100-300 ppm:The olfactory nerve is paralyzed after a few inhalations and the sense of smell disappears • 300-500 ppm: H2S reacts with water in lungs to form acid which can cause pulmonary edema • 500-1000 ppm: Strong effect on central nervous system and causes respiratory system to shut down • 800 ppm: lethal concentration for 50% of humans for 5 minutes of exposure (LC50). • 1000 ppm: Immediate collapse, even after inhalation of a single breath, and death within minutes. 17-2122 Page 10 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho 1:\B0I_Pr0jects\17\2122-Twnn Falls Grandview Odor\Memo\-rM-Fall 2017_3.14.201&doa Liquid Phase Odor Monitoring Equipment and Methods Murraysmith collected liquid wastewater samples on December 7, 2017 taken throughout the day along the Grandview Trunk. The vapor phase monitoring locations were sampled as well as the Glanbia discharge, Lamb Weston Discharge #1 (Upstream discharge at manhole C5-2), Lamb Weston Discharge #2 (Downstream discharge at manhole C4-322), and New Manhole upstream of manhole C5-2 which is just upstream of Lamb Weston Discharge #1. The samples were tested for Total Sulfide (mg/L) and Dissolved Sulfide (mg/L) using LaMotte field test kits (Standard Methods 4500-S2-D Methylene Blue). A Horiba U-52 portable meter with U- 52NISTtested for the following: ■ Temperature—°F ■ pH—unitless ■ Oxidative Reduction Potential—ORPmV ■ Electrical Conductivity—mS/cm ■ Turbidity— NTU ■ Dissolved Oxygen — mg/L ■ Total Dissolved Solids—g/L ■ Salinity— ppt ■ Specific Gravity—unitless Liquid Phase Results Table 7 summarizes the results of the sampling. In general, the sulfide concentration is higher in the upstream portion of the Grandview Trunkline in the area of S1. It also was detected downstream of the Rock Creek Lift Station. This could be due to generation of sulfide in the lift station wet well which then is passed further downstream when the lift station operates. After reviewing the vapor phase odalog data and the liquid phase testing result, the liquid phase testing was completed during a time of lower collection system vapor H2S levels and the concentration of liquid phase sulfide would likely have been much greater if sampling occurred during peak vapor phase 1-12S concentrations. The highest concentration of sulfides in the Grandview Trunk are likely much higher than tested during this study. The sampling also showed the wastewater in the Grandview Trunk is very warm beginning at S2 and continuing downstream. The presence of negative ORP and dissolved oxygen was unexpected. Typically, the presence of dissolved oxygen corresponds to ORP of greater than 50 mL ORP. Due to the complexity and difficulty of measuring DO in field conditions, the ORP is likely the plausible data. At the negative ORP values observed, typical microbiological reactions such as sulfide formation, acid formation (fermentation) and methane production can occur. The sulfide concentration and pH of the sample at the new manhole upstream of Lamb Weston Discharge #1 is quite high which causes sulfide to remain in solution. But, as the wastewater mixes with more wastewater further down the trunk, the pH will decrease and sulfides can more readily come out of solution. 17-2122 Page 11 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.201&doa As seen in the Table 7, the Glanbia discharge is very high in turbidity, TDS, salinity, and specific gravity. It also had a particular and very strong odor and detectable sulfide. Glanbia also discharges a strong waste stream as summarized in Table 2. Lamb Weston Discharge #1 was noted to have a strong odor and detectable sulfide. Lamb Weston Discharge #2 is very warm and had a positive oxidative reduction potential. The sample taken did not have any detectable sulfides. The visual observation of this sample noted that it had black flecks and white floating material in the sample. 17-2122 Page 12 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho l:\B0I_Pr0jects\17\2122-Tvnn Falls Grandview Odor\Memo\TM-Fall 2017_3.14.201&doa o Z Z M � N m Z Z Z Z O Z O Z Z Z C LL o o � a O o 3 Y v Z Z ry N m Z Z Z Z O O Z Z ry Z l'7 O � O O O O O O O O O O O O n to M to N ul N M N M fV I t0 10 l0 n N N O o N N N N - N M n oo ,n n v to tp .-+ M m m n n to to W � n m lD O t0 n n N t0 - m am m N O to 0 0 N N M N N Noo N 0p t0 N m rl w o r-I w m m M e-1 ti V V C ^ w m m o w 'D V w M 00 ^ M ID ll1 m Ocl 10 N '4 -4 N 7 V 10 V to M tD In M O N to oo M .-1 V1 n m o m .--I M CT N N O n n n C O ti - oo w w N �-i N N N M N Ln tD m V M V M V C 7 V V V1 oo M n T V 7 n V lD N M oo '-1 w N .--i m o oo O M O .--1 n rl M N M .--I m O 61 b n n ID l!1 oo Ln m M o0 w w M N N R o m oo n oo N O N o0 0o t0 to to V o0 tD n oo m oo n n o0 m n m m oo n oo n n n n n w n W M M 1p m t0 m m m t0 0o t0 ti N n V O o0 00 . . . V oo to oot t m m V1 00 m n m m .-t oo N I in ui tc ui too too n n n n n to to to n to to oo ao Q m a Q a a Q a ¢ a a a d a a d a M u1 V o N e-1 O N N V rl V 7t O N V o O 71 O N vt N oo N ll1 06 O M m M 0 V -- i ;4 .--I N V V Q¢ m L W € y L 0 N C _ O 4J O O ro O E Q N N to N N to M N to VI N N � L am = L N V F N a = o � �� Z ,., n N A m m LL CL N v N N O �� n N O C O G o 4 _ Z N u Monitoring Site Condition Observation During the monitoring, condition information for each site was also recorded and is summarized below. Pictures of each site are also included in Appendix 3. Site SO is just off of Washington Street and is upstream of all of the permitted wastewater dischargers. This manhole is in good condition, with no smell and appeared to have negative pressure pulling air into the collection system during onsite investigations. Site S1 is down in the rock creek drainage and is a new manhole that was installed in late-summer of 2017. No smell was perceived coming out the manhole and there was negative pressure pulling outside air into the manhole. Site S2 is a manhole in the rock creek drainage that was wet, slimy, and had corrosion. Site S3 is a manhole that was very wet with a thick slime layer growing and covering much of the manhole. The concrete in the manhole is in bad condition and the lid and frame are badly corroded. This site was very odorous and could be smelled 20-feet away while approaching the manhole. Site S4 is the discharge manhole of the force main from Rock Creek Lift Station. The manhole was wet, had little to no smell and possibly had negative air pressure. The wire mesh reinforcing is visible through the concrete due to corrosion. Site S5 is manhole with two large diameter pipes entering the manhole. The concrete in the manhole is in bad condition. During investigations, the manhole was under negative pressure and little smell was observed. The manhole at Site S6 is in very bad condition and smelled with positive pressure pushing air out of the collection system. Site S7 is a manhole with concrete in bad condition. However, there was no smell coming out of the manhole because it was under negative pressure and pulling air into the collection system. Site S8 is a square concrete collection box with a stainless-steel double-leaf lid. This site has corrosion and aggregate is visible with rebar discoloration showing through.The headspace in the box is under positive pressure and smells. Conclusions This study is the beginning of the City's efforts to control odor and corrosion along the Grandview Trunkline. This study has determined the following conclusions: ■ The Grandview Trunkline sewer has odorous wastewater which can be smelled in places along the entire alignment without opening manhole lids. 17-2122 Page 14 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho I\130I_Projects\17\2122-Twin Falls Grandview Odor\Memo\TM-Fall 2017_3.14.2018.doo, ■ Conditions are ripe for generation of odors, H2S, and corrosion of the collection system: o High concentrations of sulfides in solution. o Warm wastewater leading to condensation and biofilm growth. o Poor air movement in areas of collection system: tightly fitting composite manhole lids, both positive and negative air pressure observed. ■ Severe corrosion exists on manholes, lids and frames along the entire trunkline and is consistent from the upper areas to the lower areas of the trunkline. ■ Manholes need to be repaired, rehabilitated and replaced. ■ Any non-plastic pipelines are likely is similar condition to manholes and need to be repaired, rehabilitated and replaced. Other utilities have started treating wastewater at liquid sulfide concentration of 1 mg/L with the goal to get concentration below 0.3 mg/L.This study observed sulfide concentration above 4 mg/L during a time of "low" observed sulfides. Concrete begins degrading with any H2S in headspace and typical treatment goals are below 5 ppm. This study had as high as 333 ppm observed. Recommendations Based on this study, Murraysmith recommends the following future tasks: ■ Progressively Evaluate Hydrogen Sulfide Management Alternatives o Evaluate Liquid Phase Chemical Treatment Options ■ Evaluate Alternatives for liquid treatment including chemical review. ■ Complete sampling and chemical jar testing of the industrial discharges to determine optimal dosage of treatment chemicals o Evaluate Alternatives to Ventilate Trunkline Headspace into an Odor Control System ■ Liquid Phase Treatment Pilot o Complete a pilot program and feasibility study of liquid phase treatment at select locations. ■ Vapor phase treatment at key location of the Grandview Trunkline o Complete a pilot program and feasibility study of vapor phase treatment of the Grandview Trunkline. 17-2122 Page 15 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho I\130I_Projects\17\2122-Twin Falls Grandview Odor\Memo\TM-Fall 2017_3.14.2018.doo< ■ Rock Creek Lift Station FOG Control o Study and evaluation of the fats, oil and grease control at the Rock Creek Lift Station which have led to operation/maintenance problems and odor generation at the lift station in the past. ■ Inspect and assess the corrosion damage to both pipe and manholes along the Grandview Trunkline o Pipeline condition assessment — Confirm pipe material, size, and age at a minimum. o Manhole condition assessment—Confirm material, size and age at a minimum. o Program should include repair, rehabilitation and replacement alternatives analysis. o Program should include sewer infrastructure prioritization of repair, rehabilitation and replacement. 17-2122 Page 16 of 16 Grandview Odor Control Study March 2018 City of Twin Falls, Idaho I\130I_Projects\17\2122-Twin Falls Grandview Odor\Memo\TM-Fall 2017_3.152018.doo< y , I — T _._ {1 ti er ,-_,�,�p l �y�!��YY` r'T�rYlS7cL� '.Y�~ 7 Ry"�"^'�� •. I•E,��1`� �,��M. ` i� I � 1 ^ ^- t . 171 �q lYd k 4 ac Mgi� ...t-.�� % r �a C � �•?� r..ts.4_c� ��Y � •� e �� w� �� it^r,�� w� yr.- ar�.-� yf'�F_y��Yaey `�'�tf,.rt`-ac '� i�� gafi•;•� •,.I� �� ', 1� {!i". ai( ��di� y.��,��. �•:• 5Cr ��~ � �at' 7Y REM �!'� �tiZ ��}�`;'�la,'��py'•Qr 14��♦ f iifT�y��i"78�+1 .F.k Y ,. fk��,y.` fk'PSY Irl1SH^ •.i _w1]I 6' lh llljll �� • ��` � • �,24 } r 99 OS 091-SJ H W v ra E spoof eiquelE) 0£-S HA v7 auolSde>l LLT-SD HW y C Y C anuany Wd L laaaJ N L r 4A i T#uolsaM gwel Z-SD HW ii C7 TS L-bJ HW Z#uo;saN\gwel ZZ£-bJ HW aSpu8 AaoPiA ZS b-bJ H W £S OT178 HW v o a, — v U 0 , � J 0£AMH bS S-b8 H W apuduawd T-b8 HW anuand aali j SS £T-£8 HW anuandspej 9S T-£8 HA peon auil alod LS ZT-19 HA 8S SZ-TO HA d1MM '*>murraysmilh Technical Memorandum ES Grandview Odor Control Study — Phase 2 2019 Work — Executive Summary City of Twin Falls, Idaho S\p NA( f� / Date: March 17, 2021 ENSF�G e � r Project: City of Twin Falls: Grandview Odor Control Study Phase 2 15708 To: City of Twin Falls, Idaho �r9�qjF OF From: Murraysmith 94A. CUMM� Introduction The Grandview Trunkline (Trunkline) is a major part of the City of Twin Falls' (City's) sewage collection system and has historically had citizen complaints due to odor.The concrete manholes, cast-iron frames and lids along the trunk are also in in varying states of decay due to corrosion. The Grandview Trunkline stretches over 5 miles from the canyon edge along Canyon Rim Road, Grandview Drive, Filer Avenue, cross-country past the County West building, down into Rock Creek and south along Washington Street. This study included multiple phases of field work to investigate the odors and corrosion in the Grandview Trunkline. This included collection system condition data collection, collection system sampling (liquid and vapor phase), evaluation of vapor phase and liquid phase treatment options, development of solution alternatives with associated capital and life cycle costs estimates, and selection of the preferred mitigation option(s).This work is documented in several memoranda as outlined below. Subsequent elements of this project will include design of solution alternatives and associated capital and life cycle costs, design of the selected alternative, and bidding and construction phase support. Technical Memorandum 1 — Introduction The Grandview Trunkline generally flows from south to north and collects from a large portion of the City's sewage collection system. For the purposes of this study,the Grandview Trunkline begins near the intersection of Washington Street and Highland Avenue and continues north to Canyon Rim Drive. The pipes in the Trunkline are 18-to 48-inch in diameter and there are approximately one hundred manholes along the trunk. 17-2122 TM ES Page 1 of 4 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho The City's Rock Creek Lift Station is located one third of the way down the Trunkline.The lift station pumps sewage from an area down in the Rock Creek Drainage up to an area just west of County West buildings where flows can then proceed by gravity all the way to the wastewater treatment plant (WWTP). There are four permitted wastewater dischargers in the southern portion of the Grandview Trunkline: Glanbia Nutritionals, Lamb Weston Inc., Aramark Uniform Services (formerly AmeriPride Linen and Apparel Services), and West Rock (formerly Kapstone Container Corporation). Technical Memorandum 2 — Liquid Phase Investigation and Treatment This memorandum documents the evaluation of liquid phase treatment options, liquid treatment collection system sampling, and liquid phase pilottreatment. Development of solution alternatives with associated capital and life cycle costs estimates are documents in a separate memorandum. Technical Memorandum 3 — Vapor Phase Investigation and Treatment This memo documents the vapor treatment collection system sampling,evaluation of vapor phase treatment options, and vapor phase headspace airflow evaluation. Development of solution alternatives with associated capital and life cycle costs estimates are documents in a separate memorandum. Technical Memorandum 4 — Rock Creek Lift Station The Rock Creek Lift Station is a part of the Grandview Trunkline in the City of Twin Falls' (City's) sewage collection system. The lift station wet well has experienced significant fats, oil and grease (FOG) accumulation and requires manual removal of the FOG. This memo documents the City's potential options to mitigate the FOG. Technical Memorandum 5— Condition Assessment The purpose of this memo is to document a high-level assessment of the condition of the Grandview Sewer Trunkline pipeline and manholes and associated rehabilitation and/or replacement costs. Technical Memorandum 6— Conclusions, Recommendations Improvements This memorandum presents the study's conclusions, recommendations and proposed improvements for the Grandview Sewer Odor Control Study. Conclusions Conclusions from this work include: 17-2122 TM ES Page 2 of 4 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\BCI_Proje^_ts'',17\2122-Twin Falls Grandview odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Memos 2019 Work\0 Ese`ut)ve Summarv\TM-Fall P2.0 ES_03.11.2021.doa ■ The Grandview Trunkline sewer has odorous wastewater which can be smelled in places along the entire alignment without opening manhole lids. ■ Conditions are ripe for generation of odors, H2S,and corrosion of the collection system: o High concentrations of sulfides in solution. o Warm wastewater leading to condensation and biofilm growth. o Poor air movement in areas of collection system: tightly fitting composite manhole lids, both positive and negative air pressure observed. ■ Severe corrosion exists on manholes, lids and frames along the entire Trunkline and is consistent from the upper areas to the lower areas of the Trunkline. ■ Manholes need to be repaired, rehabilitated and replaced. ■ Any non-plastic pipelines are likely is similar condition to manholes and need to be repaired, rehabilitated and replaced. ■ Liquid— Ferric chloride was partially effective during jar testing. ■ Vapor— Multiple vapor phase treatment installations would be required. ■ Rock Creek Lift Station—The Rock Creek Lift station is a potential source of odor as the accumulated fats, oil, and grease begin to breakdown in the wet well. The removal of the accumulation also requires operations and maintenance staff time which is and additional cost to the City. Recommendations Based on this study, Murraysmith recommends the following which are addressed in subsequent memoranda: ■ Liquid Phase Treatment—Complete ferric chloride pilot treatment ■ Vapor Phase Treatment — Due to capital cost, vapor phase treatment is not recommended. ■ Inspect and assess the corrosion damage to pipe and manholes along the Grandview Trunkline: o Pipeline closed circuit television condition assessment—Confirm pipe material and condition at a minimum. o Manhole condition assessment— Field confirm material, condition and size. 17-2122 TM ES Page 3 of 4 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:'\130I_Proje^_ts'',17\2122-Twin Falls Grandview odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\0 Ese`ut)ve Summarv\TM-Fall P2.0 ES_03.11.2021.doa ■ Begin pipeline and manhole rehabilitation program: o Prioritize repair, rehabilitation and replacement of pipeline and manholes. ■ Rock Creek Lift Station FOG Control— Implement FOG pilot treatment and control. 17-2122 TM ES Page 4 of 4 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:'\130I_Proje^_ts'',17\2122-Twin Falls Grandview odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\0 Ese`ut)ve Summarv\TM-Fall P2.0 ES_03.11.2021.doa ,>murraysmith Technical Memorandum 1 Grandview Odor Control Study — Phase 2 2019 Work — Introduction City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Background Information Introduction The Grandview Trunkline (Trunkline) is a major part of the City of Twin Falls' (City's) sewage collection system and has historically had citizen complaints due to odor.The concrete manholes, cast-iron frames and lids along the trunk are also in in varying states of decay due to corrosion. The Grandview Trunkline stretches over 5 miles from the canyon edge along Canyon Rim Road, Grandview Drive, Filer Avenue, cross-country past the County West building, down into Rock Creek and south along Washington Street. This study is the second phase of a project to control odor and corrosion in the Grandview Trunkline. This phase included collection system condition data collection, refined collection system sampling (liquid and vapor phase), evaluation of vapor phase and liquid phase treatment options, development of solution alternatives with associated capital and life cycle costs estimates, and selection of the preferred mitigation option(s) in multiple memoranda. The previous phase of this project included collection of general system sampling (liquid and vapor phase)to help delineate and quantify problems areas. Subsequent elements of this project include design of solution alternatives and associated capital and life cycle costs, design of the selected alternative, and bidding and construction phase support. Phase 1 Overview Phase 1 of this project included sampling of liquid and vapor in the existing Grandview Trunkline to determine the extent of the problem areas. Phase 1 concluded that the Grandview Trunkline sewer has odorous wastewater along the entire alignment, conditions are ripe for generation of 17-2122 TM 1 Page 1 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho corrosion of the collection system, and the existing concrete components have severe corrosion. The technical memorandum documenting the work under Phase 1 is included in Appendix 1. Grandview Trunkline The Grandview Trunkline generally flows from south to north and collects from a large portion of the City's sewage collection system. For the purposes of this study,the Grandview Trunkline begins at manhole C5-160, near the intersection of Washington Street and Highland Avenue, and continues to manhole 131-28. The pipes in the Trunkline are 18-to 48-inch in diameter and there are approximately one hundred manholes along the trunk. The Grandview Trunkline is shown in Figure 1 and as a schematic in Figure 2, both figures are at the end of the memorandum.The City does not routinely inspect or clean the Trunkline because flow and velocity is high enough that solid deposition has not historically been a problem. Rock Creek Lift Station The City's Rock Creek Lift Station is located one third of the way down the Trunkline.The lift station pumps sewage from an area down in the Rock Creek Drainage up to an area just west of County West buildings where flows can then proceed by gravity all the way to the wastewater treatment plant(WWTP).The lift station has two separate wet wells.The lift station has seven 50-horsepower (hp) vertical-coupled pumps each rated with a design capacity of 2,073 gallons per minute (gpm). From January 1 to August 24 of 2018, the average flow pumped by the lift station was 3,535 gpm (approximately 5.1 million gallons per day). Each pump has a pump on and off setpoint and the pumps are each outfitted with a variable frequency drive (VFD). The lift station has been noted in the past as a source of odor, particularly in the summer. Additionally the lift station has experienced significant fats, oil and grease (FOG) accumulation and requires manual removal of the FOG. Industrial Wastewater Dischargers along the Grandview Trunkline There are four permitted wastewater dischargers in the southern portion of the Grandview Trunkline: Glanbia Nutritionals, Lamb Weston Inc., Aramark (formerly AmeriPride Linen and Apparel Services) and West Rock(formerly Kapstone Container Corporation). Each of the industrial discharge permits is included in Appendix 2 and is summarized in Tables 1 through 4 with actual 2018 quantities for comparison.The location of the industrial dischargers is also shown on Figure 1 and Figure 2. Glanbia Nutritionals Glanbia Nutritionals (Glanbia) is a dairy processing facility and discharges its wastewater to the collection system between Diamond and Washington Street(just north of the Glanbia facility).The flow from Glanbia ultimately joins the Grandview Trunk at manhole C5-30. Glanbia does not have a pretreatment system but does have an equalization basin that it uses at times to keep flow within their discharge permit(permit requirements shown in Table 1).The 2018 Glanbia wastewater had a high Biochemical Oxygen Demand (BOD5) concentration, total suspended solids (TSS) 17-2122 TM 2 Page 2 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\130I_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt EEval Results\Memos 2019 Work\1 Background Intro Memo\TbhFall P2 Intro ResulG_03.112021.dooc concentration, relatively high hydrogen potential (pH) and at times, high levels of FOG. Glanbia's wastewater discharge represents approximately 14.2 percent of the BOD5 and 8.3 percent of the wastewater flow that the WWTP treated on average in 2018. Table 1 Glanbia Foods, Inc. — Industrial Wastewater Discharge Permit and 2018 Data Summary4 Constituent Permit Daily Average Minimum Ma)dmum Flow (MGD1) 0.700 0.630 0.440 0.745 BOD5 (lb/day2) 5,462 3,156 1,129 16,718 BOD5(mg/L3) NA 599 230 3,070 TSS (lb/day) 1,858 1,386 474 4,705 TSS(mg/L) NA 264 92 880 FOG (mg/L) 200 61 25 104 pH 6.0 to 9.5 8.5 4.6 11.5 Note: 1. Million Gallons per Day 2. Pounds per day 3. Milligrams per liter 4. Data: 1/1/2018 to 8/25/2018 Lamb Weston Inc. Lamb Weston Inc. is a food processor that has two discharge points to the Grandview Trunkline. The first discharge is at manhole C5-2 and does not have any pretreatment.The second discharge is at manhole C4-322 and has been pretreated with an Upflow Anaerobic Sludge Blanket (UASB) pretreatment process with post-aeration. On average, Lamb Weston's wastewater discharge represents approximately 11.9 percent of the BODS and 19.3 percent of the wastewater flow that the WWTP treated in 2018. Lamb Weston's permit requirements are shown in Table 2. 17-2122 TM 2 Page 3 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\130I_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt EEval Results\Memos 2019 Work\1 Background Intro Memo\TbhFall P2 Intro ResulG_03.112021.dooc Table 2 Lamb Weston Inc. — Industrial Wastewater Discharge Permit and 2018 Data Summary 1 Permit Daily Permit Daily Clean-up Days Days Flow(MGD) 2.8 2.8 1.465 0.0 1.897 BOD5 35,000 16,500 2,639 0 20,135 (lb/day) D12 706 D120 D11,830 BODS (mg/L) NA NA D23 (UASB)155 D2 (UASB) 27 D2 (UASB) 307 TSS (lb/day) 12,000 12,000 2,661 0 9,552 D1550 D113 D12,760 TSS (mg/L) NA NA D2 (UASB) D2 (UASB) 22 D2 (UASB) 2,417 8,270 FOG (mg/L) 200 200 D18.0 D10.0 D18.2 D2 (UASB) 10.0 D2 (UASB) 7.9 D2 (UASB) 8.3 pH 6.0 to 9.5 6.0 to 9.5 D17.8 D1 7.1 D18.2 D2 (UASB)8.1 D2 (UASB) 7.9 D2 (UASB)8.3 Note: 1. Data:1/1/2018 to 8/25/2018 2. Discharge 1. 3. Discharge 2. Aramark Uniform Services Aramark Uniform Services (Aramark), formerly AmeriPride Linen and Apparel Services discharges to the collection system near 5th Street West and 2nd Ave West, which is a considerable distance away from the Grandview Trunkline. The flow from this discharger ultimately enters the Trunkline at manhole 134-1. Aramark does utilize a Dissolved Air Floatation Thickener (DAFT) process to pretreat its wastewater prior to discharge. Aramark's discharge permit requirements are shown in Table 3. 17-2122 TM 2 Page 4 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\BCI_Projects'',17\2122-Twin Falls Grandview 0dor\Phase2\Task3 45 Sampling Aft EEval Results\h1emos 2019 Wor0j Background Intro Memo\110-Fall P21ntro ResulG_03.112021.docx Table 3 Aramark Uniform Services — Industrial Wastewater Discharge Permit and 2018 Data Summary 1 Constituent Permit Daily Average Minimum Maximum Maximum Flow(MGD) 0150 *0.085 * 0.0 0.149 BOD5 (lb/day) 500 165 65 369 BOD5 (mg/L) NA 164�� 70 436 TSS (lb/day) 500 77 25 625 TSS(mg/L) NA 25 586 FOG (mg/L) 500 42 8 158 pH 6.0 to 9.5 6.8 9.5 Note: 1. Data:1/1/2018 to 8/23/2018 KapStone Container Corporation West Rock, formerly KapStone Container Corporation discharges to the sewer system at Blake Street South, upstream of the Grandview Trunkline and flow from this discharger ultimately joins the Grandview Trunkline at manhole C5-177. west Rock utilizes a Beckart filter press to pretreat wastewater prior to discharge to predominately remove dye. West Rock's discharge permit requirements are shown in Table 4. Table 4 West Rock — Industrial Wastewater Discharge Permit and Data Summary Constituent Permit Daily Average Minimum Maximum Maximum Flow(MGD) 0.130 ��0.003 0.000 0.011 BOD5 (lb/day) 984 18 0.3 71 BOD5(mg/L) Na 644 134 2,165 TSS (lb/day) 960 6 0.1 24 TSS(mg/L) N 192 60 500 FOG (mg/L) 200 15 4 27 pH 6.0to 7.7 7.1 8.0 Note: 1. Data: 1/1/2018 to 8/25/2018 Wastewater Treatment Plant Flow Data The City has provided 2018 calendar year influent data from the WWTP for this study,summarized in Table 5. 17-2122 TM 2 Page 5 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\Bol_Projects'',17\2122-Twin Falls Grandview 0dor\Phase2\Task3 45 Sampling Aft Eval Results\h1emos 2019 Wor0j Background Intro Memo\TbhFall P21ntro ResulG_03112021.00a Table S 2018 WWTP Influent Data Summary 1/1/2018 to 8/26/2018 Constituent Average k Ma)dmum Day D- Flow(MGD) 7.6 8.0 8.5 11.4 BOD5 (lb/day) 22,216 27,995 31,875 46,081 BOD5(mg/L) 352 476 574 791 TSS (lb/day) 14,729 16,768 17,873 23,233 TSS(mg/L) 233 259 304 348 Temperature 64.7 76.3 Max 77.8 Max 71.2 Max (degrees Fahrenheit) 54.3 Min 51.6 Min 46.0 Min pH 8.3 8.4 Max 8.5 Max 8.8 Max 8.2 Min 7.8 Min 7.4 Min 17-2122 TM 2 Page 6 of 6 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I`,BOi_Prcjec:s'+17%,2122-Twin Falls Grandvnew 0dor\Phase2\Task3 453ampling Alt E4 Results';Rlemes 2019 WoWj Background I=o Nleme�,T%I-Fall P2 mire ResulG_03-112021.doa f� 4T* IL® v J .;� I 1'f.- .I 1l �' �n4�V�P.tr.'. --'1 - i 1 •' i � \ �aa�y11--��ff ( ' � , / • � �iV' 11+ `� �� 1. I ] �,r x it Ak Legend m Rock Creek Lift Station— Rock Creek Force Main Grandview Sewer Gravity •�� •�� Grandview Odor Control Study Figure 1 09T-S:) H W U N spoof elquelE) OE-S HW N i auojSdeN LLT-SJ HW Y C anuany Jed L r` L v N dA i T#uo}saM gavel Z-S0 HW iz l7 TS L-bJ HW Z#uolsaM gavel ZZE-bJ HW a2lppq AaoIJln ZS b-b:)H W OT-b8 H W `4 C: o L U � Y Cn U N � o w OE AMH S-b8 H W apudlaauay T-b8 H W anuany Jalld SS ET-E8 HW anuany sllej T-E8 HA peon aull alod ZT-TO HA 8s 8Z-TO HW d1MM '>murraysmith Technical Memorandum 2 Grandview Odor Control Study — Phase 2 2019 Work — Liquid Treatment City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Introduction This memorandum documents the evaluation of liquid phase treatment options, liquid treatment collection system sampling, and liquid phase pilot treatment. Development of solution alternatives with associated capital and life cycle costs estimates are documents in a separate memorandum. Liquid Phase Sampling Murraysmith collected liquid wastewater samples on August 7, 2018 and August 14, 2018. The samples were tested with a Horiba U-52 portable meter for a number of components, samples were taken for BOD5 lab analysis and samples were also tested for sulfide concentration. The results are summarized in Table 1. In general, the sulfide concentration is higher in the upstream portion of the Grandview Trunkline in the area of S1. 17-2122 TM 2 Page 1 of 19 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho ' O O O O O 00 oN0 O = o 0 O 0 O 0 O 0 CD0 O 'o O O O O O O O O O O vi LL N v t0 �6 _C O O o0 1l O t- oo r Ln 00 Ln m �,o N � 0 r-I Ln N o (A V O 4'.; Ln C 00 M V Ln 00 O O t- Izi- 00 00 0') O • O �o O -D .1 N f, to N N N 00 u o EN —i N r�l —I —I --i m —4 m K:T 8 O —i O N M > o 00 O O o m o 0 C 0 ry) _0 o �o l� 0 N Ln m �D Ln 00 0) m ^ t� O Ln M I, lD M O Ln — l0 O Ln • _ 0 to u 0m un 1.0 N —1 Ln Ln O V) 00 0] m 00 N m d' rN 1-1 r� m —1 00 O v N m M m v cn m v m m N 0 s w I� un un rn m N lD m 00 N lD Ol M M d O M lD Ln (- d 1. a a--I M m 4 m M m M m 1.D co = p c cN i G � it m m o0 l0 M O � N ^ ^ c 0. Ln O o 00 -I - `� N Ln . 1 N E • • 5 U 5 V t0 i� -i T u1 O � fi 00 00 00 00 m 0000 00 Ln 6 6 rV C E E fr Q d O O �o N �O i 00 d d of V) N —� M cf —I O I-� 00 r� I� l0 O ry r� 00 n 00 0) 00 n r 00 00 n 00 u 4- EC t (O y 00 00 00 00 00 00 t�ii c -a 3 v 00 00 00 00 00 00 a O ry O m O ry O m O ry CD , rp , Ov \ O O O \ ` ` ` O 00 Z0 floO OO m rMrmrOr O O N m o00� 00 & 0 000 � -- C, m —r W ac a v E o E T !� N n 0 a —� N N N .. z Ez o 000 rn r x* 00 m rc r m +°' N N t —,J rmn Eo — m Eo u z u m r, m m m um In— 00 Lr) vN J � Liquid Phase Treatment In the liquid phase, reduction of the anaerobic activity and/or the generation of malodorous compounds such as hydrogen sulfide (1-12S) in a collection system can be achieved through a number of biological and chemical methods. The following discussion and Table 2 provide a general summary of these options. Biological These solutions focus on changing the biological activity of the sewer bacteria to prevent or suppress the formation of sulfides by: ■ Providing elemental oxygen (higher dissolved oxygen levels) to limit anaerobic conditions ■ Providing nitrate as an oxygen source to limit anaerobic conditions Chemical These solutions are based on adding chemicals to the collection system flow to achieve one of three H2S mitigation measures: ■ Reduce or prevent the formation of sulfides (chemical oxidation) ■ Delay the release of sulfides from solution (hydrogen potential (pH) adjustment) ■ Reduce or eliminate the release of sulfides (chemical precipitation) 17-2122 TM 2 Page 3 of 19 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Mema\TM-Fail P22 Liquid 03.11.2021_doa / 0 / \ } % E \ » § \ 2 e E 3 c / i . / / / , 0 @ � e e J \ e e / : 2 2 R E E 2 = m u / ro u 4 E / / \ \ \ = f _ 7 / ® / _ \ _ \ ® / / 6 \ 3 3 \ 20 2 2 m E u E ± c m s u c e 2 \ 2 2 % E / G k \ k G \ \ \ k t \ 6 7 c ' e E � . e e l t J 2 c a . / c 2 7 2 \ 3 e « ° n ° $ \ / = 7 6 : 3 3 } \ m ) / % % u m e 2 / = M / m e / t } o t / c t 9 ƒ % 7 3 \ c s 6 \ © - � / 7 6E \ u / u AEE g 3 2 c 2 / » % / » e c 3 2 3 - 2 R C� - / u \ % ƒ \ % 7 § 20 x * z Z J » » ! TO ® E E v \ ƒ ' I - 2 % > > LA $ 0 ) § ° E 7 # \ » CL E * x I < y » : » % t ' o G E y t 2 2 / d 2 � § / \ } / cc f ( E C3 / \ L \ c § ) $ & Z a / m £ c & E \ E I \ \ ƒ / 0 \ / 3 / 0 [ \ u 0 2 = _ a 2 u § \ k \ E 9 E 9 3 - } CL \ k a = 2 z } ? - � & \ 2 2 ` 0 2 $ g e 9 / = m = Ln \ 2 / \ f u _ = S \ o a ° E :E / ° 2 m % } e U CL m k ° @ee � 2 . \ k \ / 0 / ) } � \ � \ ƒ § # ^ \ _9 § a / / J * / e m \ ° � � \ E X Cl) 5 CD E L { f / « \ / 7 _0® 2 ® = o = : E to / / £ ± > u k ' § > - / D / e b J u o e 7 ® E c ( 9 / / / o \to C § \ / ro % ° = 9 6 7r3 \ « \ y k / \ ƒ o tz 0R * to m MDm3 \ a \ � / a p E _ � = 3 g u j : y s a 2 2 / ma ƒ / & / / \ C \ ' _ 5 f a ± f f 2 » \ E ) 2 } \ /a \ t © * \ % ) _ 2 \ } cl: } § § w k } p } / / k / } / ? _ - � u 4� o / % mr4i m x 2 0 \ 5 / � . % \ \ Liquid Phase Jar Testing Jar testing of chemicals was completed on August 7, 2018 and August 14, 2018.The jar tests were set up to mimic the conditions in the collection system: in 500 milliliters (mL) beakers, a stir bar agitated the wastewater similar to the mixing that occurs as flow travels in the open-channel sewer pipe. A variety of chemicals and chemical doses were added to the wastewater samples and measurements were taken of the headspace hydrogen sulfide concentration with a Jerome Hydrogen Sulfide Analyzer. Higher concentrations of sulfide in the headspace correlate to a chemical dose that is less effective than a lower concentration in the headspace. For comparison, a control beaker with no chemicals added was used to compare to untested natural conditions. Hydrogen peroxide Hydrogen peroxide is an oxidizing agent that can reduce or prevent formation of sulfides and can also be effective for treating odors beyond those from sulfide.The dosage is dependent on sulfide level and is only effective for a short time. It can also take up to 30 minutes to fully react and must be dosed high up in the collection system to have maximum benefit further down in the collection system.The reaction time can be decreased by using iron and peroxide simultaneously. Table 3 summarizes the jar testing results. Jar testing with hydrogen peroxide was found to be ineffective in removing odors and hydrogen sulfide, even after 30 minutes of reaction time. High doses of hydrogen peroxide with 10 milligrams per liter(mg/L) of ferric chloride did show promise, but this would be costly and not as effective as other options. The jar testing from B3-13 and C4- 4 shows very little sulfide in the control beaker which is likely due to dilution in the collection system. Due to the limited treatment attributed to hydrogen peroxide, this chemical is not considered feasible for treating odors in the Grandview Trunkline. 17-2122 TM 2 Page 6 of 19 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021_doa Table 3 Hydrogen Peroxide Jar Testing Summary Hydrogen Sample Location Peroidde Date d. p . c- Hydrogen SuMde Dose (ppm) Glanbia Discharge 63-13 C44 w/10 mg/L Ferric Chloride @ 15 min, @30 min @ 15 min, @30 min l8/7/2018 0(control) -50 0.119, 0.148 0.147, 0.026 8/7/2018 5 >50 0.145, 0.122 0.139,0.12,' 8/7/2018 10 43 0.138, 0.11 0.143, 0.27 8/7/2018 20 23 0.144, 0.137 0.147, 0.49 l 8/7/2018 40 12 0.141, 0.125 0.144, 0.70 Glanbia Discharge C4-7 C4-4 @ 15 min, @30 min @ 15 min, @30 min @ 15 min, @3 min 8/14/2018 0(control) 8.4, 7.36 7.7, 4.3 0.18, 0.17 8/14/2018 5 5.5, 7.4 6.7, 3.6 0.191 0.16 8/14/2018 10 6.1, 6.6 2.0, 1.1 0.16, 0.15 8/14/2018 20 4.5, 6.1 5.3, 3.6 0.21, 0.15 8/14/2018 40 4.5, 3.7 3.0, 3.5 0.35, 0.21 Sodium Hypochlorite Sodium hypochlorite, commonly referred to as bleach, is an oxidizer and disinfectant. As an oxidizer, it reduces or prevents formation of sulfides and the reaction occurs almost instantly. In the absence of ammonia, the dose ratio is 9.4 pounds (Ibs) NaOCI to 1 lb H2S with practical dose rates anywhere from 10 to 15 depending on the application. In the presence of ammonia (which is the case in municipal wastewater),the dose ratio is 2.3 Ibs NaOCI to 1 lb H2S with practical dose rates anywhere from 3.5 to 5 depending on the application. Overdosing of sodium hypochlorite can lead to corrosion in the collection system. Disinfection byproducts can also be created and there is concern that future Wastewater Treatment Plant (WWTP) National Pollutant Discharge Elimination System (NPDES) permits will include limits for these chemicals. During jar testing, as summarized in Table 4, sodium hypochlorite was found to be effective in the 5 to 10 mg/L dosage. The testing on August 7 showed a decrease in headspace hydrogen sulfide at low dose and then an increase at higher dosing. After consulting the Jerome Hydrogen Sulfide Analyzer company, this is likely a false positive reading due to off gassing of chlorine which interferes with the analyzer.The methods of the test were modified for the August 14 testing and the tests on that day show a good level of treatment with only 5 mg/L sodium hypochlorite dose. 17-2122 TM 2 Page 7 of 19 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOJ_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Memo\TM-Fall P22 Liquid 03.112021-door Table 4 Sodium Hypochlorite Ja Sodium 4 • !r 1 P Date Hypochlorft,. Dose 1 1 Glanbia C4-7 C4-4 B3-13 Discharge 8/7/2018 0(control) =50 7.9 12.6 0.82 8/7/2018 5 13 1.7 1.4 1.7 8/7/2018 10 1.2 3.2 2.4 4 8/7/2018 20 2.4 8.3 3.7 6.6 8/7/2018 40 3.4 10.1 3.6 4.1 Glanbia C4-7 C4-4 133-13 Discharge 8/14/2018 0(control) 6.2 3.8 4.9 2.5 8/14/2018 i 5 0.18 0.069 0.30 0.088 8/14/2018 10 0.15 0.074 0.29 0.09 8/14/2018 20 0.14 0.136 0.32 0.106 8/14/2018 40 0.16 0.18 0.45 0.0132 The cost to treat the Grandview Trunkline with sodium hypochlorite at the Glanbia discharge manhole and the Rock Creek Lift station is summarized in Table 5. Table 5 Sodium Hypochlorite Chemical Cost Summary Existing Flow Existing Flow Committed(Future) Committed Dose(mg/L) Injected at Injected at Rock Flow Injected at (Future)Flow Glanbia Creek LS Glanbia Discharge Discharge 10 $100 $590 $120 $790 Sodium hypochlorite is not considered feasible for treating odors in the Grandview Trunkline due to the cost for chemical, the potential for an overdose harming the WWTP, the potential for creating disinfection byproducts, and requirements for safe handling of the chemical. Ferric Chloride Ferric chloride is an iron salt and in the presence of hydrogen sulfide in solution, produces a chemical iron-sulfur precipitate that permanently removes the sulfur from solution. This effectively eliminates future odorous and corrosive sulfur compounds from being produced. Ferric chloride will also remove phosphorus from wastewater.The dosage of ferric chloride is dependent on sulfide concentration and will produce a sludge (> 3 lb sludge per lb sulfide) that will travel 17-2122 TM 2 Page 8 of 19 Grandview Odor Control Study-Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Llauid 03.11.2021_doa through the collection system.The theoretical dose of ferric chloride is 1.2 lb Fe3+ per lb H2S with practical dose rates anywhere from 1.5 to 4 depending on the application and water chemistry. Ferric chloride costs can vary regionally and seasonally and are very dependent on local sources of supply. It is generally not effective for (non-sulfide) organic odors. Treatment is pH dependent and it is hard to achieve low sulfide limits.The application of ferric chloride also lowers pH, which can cause any non-precipitated H2S to more easily volatilize in the collection system. Ferric chloride should be handled, stored and use carefully and it can be an environmental hazard. Table 6 summarizes the jar testing. During jar testing, the effective dose of ferric chloride was found to be between 50 and 100 mg/L. Table 6 Ferric Chloride Jar Testing Summary r. .« .. (ff WA) Hydrogen Sulfide r - . . Glanbia Discharge C4-7 C4-4 133-13 8/7/2018 0(control) >50 >50 13 1.7 8/7/2018 35 42 14 = 2.1 8/7/2018 50 0.13 13 18 2.8 8/7/2018 0.42 2 12.1MML, 3 i 8/7/2018 200 0.19 4.7 1.4 1.2 Glanbia Discharge C4-7 C4-4 133-13 8/14/2018 0(control) 7.5 7.3 3.2 3.4 8/14/2018 1 8.5 4.1 4.2 3.7 8/14/2018 50 5.4 5.9 3.1 3.0 8/14/2018 100 24# 1.5 2.7 3.1 8/14/2018 200 4.1 0.51 2.0 0.47 The cost to treat the Grandview Trunkline with ferric chloride at the Glanbia discharge manhole and the Rock Creek Lift station is summarized in Table 7. Table 7 Ferric Chloride Chemical Cost Summary Dose Exiisting Flow Injected at Usting Flow Commlitted(Future) Committed(Future) injected(mg/L) Glanbia Discharge Injected at Flow . d at Rock Rock Creek LS Glanblia DiWorge 50 $190 $1100 $220 $2280 100 $380 $1410 $440 $2930 Ferric chloride is considered feasible for treating odors in the Grandview Trunkline. However it does have high cost for chemical, potential for variation of effectiveness due to water chemistry, and the requirements for safe handling of the chemical. 17-2122 TM 2 Page 9 of 19 Grandview Odor Control Study-Phase 2 Results March 2021 City of Twin Falls, Idaho I:\1301_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Alt Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Uouid 03.11.2021.doa Nitrates - Bioxide When nitrate is present, sulfate is not normally reduced to sulfide by bacteria. In addition, when nitrate is present in excess, existing sulfide will likely be oxidized back to sulfate. Bioxide, a commercial calcium nitrate solution,controls sulfide odor and corrosion by introduction of nitrate- oxygen to the wastewater in the sewer. Bacteria in the sewer utilize the nitrate-oxygen and hydrogen sulfide in solution to produce reduced sulfur components as part of their metabolism which prevents release of hydrogen sulfide, odor and corrosion. Nitrates can be added far upstream in the collection system with benefits to the entire collection system. However, it is a biological reaction, so it is not necessarily instantaneous and to receive full benefit, it should be added continually to change the microbiology in the collection system. Additionally, bioxide only prevents further generation of sulfide and will do nothing to remove already formed sulfide. Bioxide is not able to be jar tested due to the biological nature of the treatment and the length of time needed for bacterial growth. However, the chemical supplier provided an analysis of the Grandview Sewer and recommends 460 gallons per day. The cost for bioxide is currently $3.47 and is purchased in 4,000-gallon deliveries. The chemical cost for bioxide is therefore $1,596.20 per day to treat the whole trunkline based on the vendors analysis. Bioxide is not expected to be beneficial to the trunkline because the hydrogen sulfide is predominantly discharged to the collection system rather than generated in the sewer. Maz-za/ The City has previously considered the use of the Maz-Zal pond/lagoon water and wastewater treatment system. This chemical additive contains enzymes, bacterial hormones, acid, wetting agents and surfactants. Maz-Zal is recommended to be applied at 15 mL per 3,800 liters of lagoon or pond influent. For the Grandview Trunkline, which has an average total flow of 7.8 million gallons per day (29,500,000 liters per day), the product literature recommended dose of Maz-Zal 3 parts per million (ppm) which corresponds to 30.8 gallons per day(116 liters per day) which has a 2019 cost of$28.50 per gallon for a total cost of$877.80 per day in chemical cost alone. In a previous study completed by the City, Maz-Zal was not shown to have a clear effect on the hydrogen sulfide on the trunkline and further study was not recommended. Maz-Zal brochure, MSDS and the previous City Technical Memorandum are included in Appendix 1. pH control Depending on the pH of the wastewater, the form of sulfide can vary dramatically. Since only the unionized form of sulfide(H2S)can be released from the wastewater solution, pH plays a significant role in collection system odor and corrosion. At a pH of 7, the ionized sulfides (HS- and S'--) and unionized aqueous hydrogen sulfide (H2S) are essentially equal. At higher and lower pH, however these proportions quickly change with lower pH shifting to more aqueous hydrogen sulfide and thereby increasing the rate of hydrogen sulfide transfer to the gas phase. 17-2122 TM 2 Page 10 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021_doa pH control consists of adding a chemical to the water in the collection to increase the pH to make it more basic. This can be done with many different chemicals, but sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2) and magnesium hydroxide (Mg(OH)2) are the most common.Sodium hydroxide and calcium hydroxide both have safety and handling issues while magnesium hydroxide is very safe, readily available and commonly used for odor control. Magnesium hydroxide that is used for odor control is often sold under the name Thioguard. Liquid Phase Treatment Pilot Evaluation The list of liquid treatment alternatives has been analyzed both in the office and with jar testing. Based on the results of this work and in consultation with a chemical supply vendor, a pilot chemical treatment with magnesium hydroxide was completed. Potential locations for chemical treatment are near the Glanbia discharge manhole for primary treatment and Rock Creek Lift Station for polishing treatment. For the pilot, the magnesium hydroxide was injected into the collection system just downstream of the Glanbia discharge manhole.Odaloggers were installed to monitor the 1-12S concentrations downstream of the Glanbia discharge. Figure 1 shows the locations utilized during the pilot. Magnesium Hydroxide Pilot Based on recommendations from the chemical vendor, the magnesium hydroxide was dosed into the collection system at 60 gallons per day. The system consisted of a chemical tote, pump with variable frequency drive and tubing to direct the chemical to the collection system.The system is shown in Figures 2 and 3. 17-2122 TM 2 Page 11 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021_doa t B1-2a rT a B i 1 y AmeriPride (" e F� Rock Creek Lift Station s e'C4-4 ' e Kapstone C4-`T I Lamb Weston •�' o � a Glanbia FLeegendn Manholeger Locationview Sewer Manholes -reek Lift Station view Sewer Gravity x — Rock Creek Force Main "•0 1.000 2,000 Feet S,o I igitalGlobeaGeoEv T<Earti� - }�a� --.NES Airbus IIS��- I _N.and Phe GISUser Commun ty Twuu MIN Grandview Odor Control Study Figure 1 _ TWIN murraysmith ,0,. Phase 2 Liquid Treatment Pilot s i� 4� Figure 2 Pilot System Photo 1 f r_x p4 isi' ts I 17-2122 TM 2 Page 13 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021-doac Figure 3 Pilot System Photo 2 { • _ .. T"" T'f TT I"T T T t T 1 T r T T T r T T T 11 l T I T I f rF T At `� ( -� - j • �ALWAYSI _ 1 zoa iio•a§es 733-21C h Odalogger data Four Odaloggers were placed in the collection system for recording collection system headspace H2S concentration before,during and after the chemical pilot.The data provided by the odaloggers is presented in Figure 4 through 7. 17-2122 TM 2 Page 14 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021_doa Figure 4 S1 C4-7 Vapor Phase: HZS and Temperature S1 Vipoi Phase: H25 and Ternperalurt -5111a5 14orrprr:h:rr -5urt1.•c.li•Trirprntum r•tJ :[y: y� I 90 rya f- ► � � I eo M 60 c V a i0 � n = E u 40 30 C - 20 10 a 0 17-2122 TM 2 Page 15 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I_\BOI_Projects\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Uouid 03.11.2021.docx Figure 5 S2 C4-4 Vapor Phase: HZS and Temperature r2%14pur Phase; 1125 and Temperature -52H;c -5?Tr4rpfr:1t.m -tt rtifrh YTrmprrJturp I ThC - - - - - I 83 I 70 I20 - -- 63 LL C U 7 x 5) , 'l U = d C U r Sc - 4] oc ;1 40 c R NN 17-2122 TM 2 Page 16 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021-docc Figure 6 S5 B3-13 Vapor Phase: HZS and Temperature SS Vapuir Phrase: 112S and Temperature �SiH?S —5+T�mP^tmnr —Sirf,te W T,mmrahre 11C LW -- 93 1oo — - — - —— ID tic — 70 120 60 LL C_ L G v Im f as — 43 33 an 7'1 IdL as is 17-2122 TM 2 Page 17 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I_\BOI_Projects\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Uouid 03.11.2021.dooc Figure 7 S8 B1-28 Vapor Phase: HZS and Temperature 58%lopar Phase: 1125 and Temperature -Gi I17i -SATnmr.emnire. -41mlr,r it Trmppryri" -fl:nbi "�" 11 1 I • 9l I 1 kl I R:1 10 12C G) c � c � I)C 5) ^r u` 2 E u r aC 43 aC 33 AC 2J 2C _) C C 17-2122 TM 2 Page 18 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts'•17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme\TM-Fall P22 Liquid 03.11.2021-door Magnesium Hydroxide Pilot Results Comparingthe concentration of 1-12S atthefour locations and before,during and afterthe chemical feed show the that the magnesium hydroxide pilot was marginally effective in the upper regions of the trunkline but ineffective in the lower trunkline. The dosage of the chemical could be increased, however the cost to dose at this higher rate will quickly become cost prohibitive. Conclusions The results of the sampling, jar testing and pilot evaluation show that a magnesium hydroxide liquid treatment system in the Grandview Trunkline is not a good option for treating the collection system odors and 1-12S. Pilot chemical treatment using ferric chloride is recommended directly at the Glanbia connection to the collection system. 17-2122 TM 2 Page 19 of 19Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I:\BOI_Proje:ts\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Aft Eval Results\Memos 2019 Work\2 Liquid Treatment Jar and Pilot Results Meme TM-Fall P22 Liquid 03.11.2021_doa '>murraysmith Technical Memorandum 3 Grandview Odor Control Study — Phase 2 Vapor Phase Investigation and Treatment City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Introduction This memo documents the vapor treatment collection system sampling,evaluation of vapor phase treatment options, and vapor phase headspace airflow evaluation. Development of solution alternatives with associated capital and life cycle costs estimates are documents in a separate memorandum. Vapor Phase Odor Monitoring Equipment and Methods Murraysmith, Inc. (Murraysmith) used four rented App Tek International Acrulog H2S loggers (Odalogger) odor meters for this study. Murraysmith staff,with assistance from City staff, installed the flow meters and removed them at the end of the monitoring period. Murraysmith inspected the meters intermittently to check battery status, download the data, and confirm that the equipment was operating properly. The Odalogger meters were installed on August 2, 2018 and removed on August 14, 2018. The locations where the Odaloggers were placed is shown in Figure 1 and schematically on Figure 2. 17-2122 TM 3 Page 1 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\3 Vapor Treatment Pilot Memo\TM-Fall P23 Vapor 03.11.2021.dooc u L"� B1-28 mm Wt 4111116. _ it I;•�' � ,► ter.. � ♦. W 1_ Y ,n Ameri Pride { lit fit Rock Creek Lift Station i IN . C4-4 > L 1•, _ Kapstone C4-7`� Lamb VIestor, '" Non,� � �r Glanbia iN Ml n cw. Legend cs Rock Creek Lift Station Grandview Sewer Gravity ' — Rock Creek Force Main -'- 0 1,000 2,000 Feet CNCS A,busa e�oukiu CITY OF T N FALLS Grandview Odor Control Study Figure 1 murraysmi7h Phase 2 Grandview Trunkline � 09T-S:) H W U N spoof elquelE) OE-S HW N i auojSdeN LLT-SJ HW Y C anuany Jed L r` L v N dA i T#uo}saM gavel Z-S0 HW iz l7 TS L-bJ HW Z#uolsaM gavel ZZE-bJ HW a2lppq AaoIJln ZS b-b:)H W OT-b8 H W `4 C: o L U � Y Cn U N � o w OE AMH S-b8 H W apudlaauay T-b8 H W anuany Jalld SS ET-E8 HW anuany sllej T-E8 HA peon aull alod ZT-TO HA 8s 8Z-TO HW d1MM Vapor Phase Results Table 1 summarizes the data from the individual Odaloggers which were suspended from manhole lids. The Odaloggers monitor hydrogen sulfide (H2S) gas concentration and temperature of the headspace in the collection system. Appendix 3 graphically shows the Odalogger recorded data. Table 1 Vapor Phase OdaLogger Summary (8/2/2018 to 8/14/2018) (PPM') Temperature Site Manhole ID (degrees Fahrenheit) Low Average High Low Average Highl S1 C4.7 2.0 34.2 213.0 74.5 82.0 87:4 S2 C4-4 0 8.5 50.0 78.1 84.0 86.9 s5 8 431 1 me. 79.2 886.1 91.4 S8 B1-28 0 3.5 62.0 77.9 83.5 101.7 Note 1. Parts per million Vapor Phase Treatment The control and/or treatment of the air before its release from the collection system is an effective means of addressing H2S related odor and corrosion problems. Unfortunately, the ease at which gaseous H2S is converted to sulfuric acid in a municipal sewer collection system and the susceptible nature of the collection system to corrosion means that a containment-only solution should not be considered. However, containment or control of the H2S in the gaseous phase combined with air handling/treatment techniques can be. Wet scrubbers and dry scrubbers (adsorptive processes) are the two most common air treatment techniques. Wet Scrubbers Wet scrubbing involves contact of odorous gas with a scrubber solution that transfers the H2S in the gaseous phase to the scrubber liquid by one of several mechanisms: ■ Condensation ■ Particulate removal ■ Scrubber solution absorption ■ Chemical agent emulsification Water soluble gases such as H2S, ammonia and various organic compounds may be removed by using water as the scrubbing liquid. However, the use of reactive scrubbing liquids that include chlorine, potassium permanganate, hydrogen peroxide or proprietary solutions are much more common as they help ensure dependable and higher-level removal. For these options to be feasible for a collection system, a number of factors must be considered. These include: 17-2122 TM 3 Page 4 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\3 Vapor Treatment Pilot Memo\TM-Fall P23 Vapor 03.11.2021.dooc ■ H2S generation locations ■ Gaseous H2S concentrations ■ Collection system airflow dynamics (existing and future) ■ Treatment location ■ Available land/space Dry Scrubbers Dry scrubbing involves removal of odorous gas(H2S) by molecular adhesion to the scrubber media. For H2S odor control,there are a number of media system types that can be used for this purpose. Some of the most common include: ■ Activated carbon ■ Activated alumina impregnated with potassium permanganate ■ Hydrated iron oxide on a carrier of wood chips ("iron sponge") ■ Engineered soil/compost (biofilter) The same factors that influence the feasibility of wet scrubbers also apply to dry scrubbers. Vapor Phase Treatment Evaluation This evaluation includes alternatives to ventilate trunkline headspace into vapor phase odor control systems. The collection system drawings, sewer hydraulic model and existing collection system knowledge were reviewed to identify likely hydrogen sulfide release points due to grade changes, turbulence, and headspace availability. Additionally, headspace pressure monitoring fan tests were completed to understand the zone of influence for four different extraction locations. Hydraulic Model Analysis Figures 3 through 6, at the end of this memorandum, provide graphical representation of the sewer velocity and depth over diameter (d/D) at Existing and Committed/Anticipated modelling scenarios. The velocity analysis shows the velocity of the flow in the trunkline is relatively high which will make vapor phase treatment more difficult and less effective over large areas due to the pressure differentials that the high velocity flow areas create. The d/D analysis shows the relative depth of the sewer flow to the pipe diameter, essentially showing areas that are more or less full and conversely the headspace availability. During existing and future conditions, the trunkline has available headspace for air movement during minimum, average and maximum dry weather flow conditions. Figure 7 through 10, at the end of this memorandum, provide hydraulic profiles of the Grandview Trunkline. Three separate headspace areas of trunkline effectively exist due to a full pipe flow at the Rock Creek siphon crossing and the Rock Creek Lift Station. For this study, the Upper Grandview Trunkline Area is defined as upstream of the Rock Creek Siphon (MH C5-21),the Middle Grandview Trunkline Area is from Rock Creek Siphon to Rock Creek Lift Station (MH C5-3 to Rock 17-2122 TM 3 Page 5 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\3 Vapor Treatment Pilot Memo\TM-Fall P23 Vapor 03.11.2021.dooc Creek Lift Station) and the Lower Grandview Trunkline Area is from Rock Creek Lift Station Force Main Discharge to Canyon Rim (MH 134-102 to MH B1-8). Collection System Headspace Pressure Monitoring Collection system headspace pressure monitoring consists of temporarily installing a fan to ventilate the sewer while simultaneously monitoring the differential pressure of the sewer headspace and the surface pressure at manholes at increasing distances from the fan. The fan draws fresh air into the sewer and exhausts odorous air creating suction in the headspace which can be measured with differential pressure loggers. The differential pressure loggers show the airflow zone of influence that the fan creates. For a permanent installation, the exhausted air would be treated prior to discharge. For this study a fan and six differential pressure loggers where used to confirm the effect of ventilation at four separate locations over four days:two in the Lower Grandview Trunkline Area, one in the Middle Grandview Trunkline Area and one in the Upper Grandview Trunkline Area.The pressure loggers were installed the afternoon the day before the ventilation tests to determine background conditions. The fan testing began each morning and ran for a total of approximately 2 hours. The air flow was measured with a handheld anemometer to determine the air velocity and flow rate.The test was performed with the sewer manhole lids in their normal closed position and with a manhole lid opened for a short time to determine if the system would benefit from the additional open space for air to flow. None of the tests showed a benefit from the open manhole. Additionally, the duct was taken off the fan to decrease headloss and increase the fan performance. Many of the locations showed an increase in the differential pressure showing that the fan airflow increased and suction increased as well. Figure 11 through 14 show locations of the fan and pressure loggers each day of fan testing. Graphs of the differential pressure logs are provided in Appendix 4. Table 2 summarizes the results. 17-2122 TM 3 Page 6 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\3 Vapor Treatment Pilot Memo\TM-Fall P23 Vapor 03.11.2021.dooc =ate �r.4Ttf.u„a►'VJP6 �w 1, + Ste. fr' ��r*'j 1'i'tLa t, .r-t. 3 t• —� i r Grandview '• -- - ._ .r ��,J. + 3��`�d',•%w' lip �� • i Odor Control Study Figure 11 - i ; i - Cf to r� �j Sh W. iJ . rr R 11 G o Grandview Odor Contr Figure 12 alk _ It Rock Creek Lift Station CA-2 0 Ot Legend A�AL Rock Creek Lift Station Grandview Sewer Gravity Rock Creek Force Main �-I�iO 25050OF;et Grandview •t G ..Ir't T�� y�r� J I'i'� ��f 1�� v, L r ® � �.� Lees1+ �` ..j � - r r 3 7 m t� Odor Control Study Figure 13 Tom. n � IF I TM �i4 rs ems ; - CS33' I ••�? �� i.x•' - w = r- ice• Legend is Rock Creek Lift Station i Grandview Sewer Gravity • 4 + - ,� — Rock Creek Force Main R t 0 250 500 Feet w _e, • is o "'Y�ta e - r� G graphics QNE3Ar07 ,NerooRID. J the GIS se, o'mUld OF TWU Grandview Odor Control Study Figure 14 � - S murraysmi Phase 2 Differential Pressure w 7/19 "� Table 2 Collection System Headspace Pressure Monitoring Summary DifferentialFan Average Airflow , . l Pressure Date Manhole Rate(CFM) Loner Location Location B1-47 Upstream Large B1-9 Upstream Favorable 7/16/2019 131-4 1,804 132-3 Upstream Moderate 62-10 Upstream Moderate 63-13 Upstream Minimal B4-3 Upstream Minimal 132-3 Downstream Favorable B2-10 Downstream Favorable 7/17/2019 133-1 1,814 63-3 Upstream Moderate B3-171 Upstream Moderate B3-13 Upstream Minimal 64-3 Upstream 134-8 Upstream Moderate 64-12 Upstream Minimal 7/18/2019 64-7 1,887 64-93 Upstream Minimal C4-2 Upstream Minimal C4-7 Upstream Minimal C5-3 ALT Upstream Minimal C5-30 Upstream Large C5-33 Upstream Favorable 7/19/2019 C5-177 1,588 C5-131 Upstream Large C5-160 Upstream Favorable C5-53 Upstream Moderate Conclusions Vapor phase treatment is anticipated to be beneficial to address localized odor problems and multiple installations are recommended. The trunkline is physically separated into three headspace areas and each will need its own vapor phase treatment system(s) to holistically treat the trunkline headspace. The results of the sewer review, modelling and headspace pressure monitoring were used to select locations for potential installation of five vapor phase systems as described and in Table 3: three in the Lower Grandview Trunkline Area, one in the Middle Grandview Trunkline Area and one in the Upper Grandview Trunkline Area. 17-2122 TM 3 Page 11 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work\3 Vapor Treatment Pilot Memo\TM-Fall P23 Vapor 03.11.2021.dooc Table 3 Collection System Vapor Treatment Potential Locations Grandview Extraction Distance of Trunidine Area Manhole (feet) influence Lower B1-4 7,500 81-4 to 132-3 Lower 63-1 8,830 62-3 to H-13 Lower 134-1 2,630 1W 133-13 to B4-5 Middle B4-7 7,480 B4-7 to C5-3 Upper C5-177 1,290 C5-177 to C5-33 17-2122 TM 3 Page 12 of 12 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I`,B0 i_Pr-j e-:s'+17%,2122-Twin Falls Grandvnew Odor\Phase 2\Task 3 4 5 Sampling Alt E>al Pesults161emos 2019'WorW 3 Vapor Treatment Pi lot Merrio'�T h7-Fal l P23 Vapor_03112021.doa a r •_ (`^~♦ I ` - ;� 1v¢yG I �'-��r��, .I -- ' 1/: '', to �...,.... -,' '��•7�,{ � ��t I - • ae a� Ile 1= 7r it • .' 4 _ ` - �, I �/ J •alt.. yel 1 � ''r. � r .yyb'�7p rtl�14�1�4 Y�"v'.,.• ■■ �� ."'f'",,,: ..h 'X Ij n.. --� 1. r f 1 Legend Rock Creek Grandview Sewer Gravity — Rock Creek Force Main Existing Model Average Velocity ' J- ,2 fps 2 to 4 fps I 1 4 to 6 fps 6 to 8 fps 8 fps iIIIIII see Fmurraymmith Grandview Odor Control Study Figure 3 y.'• '1 �• Tr �' �1'��Qt ! - f ` ' — I ' �.f• �.•..... �� '��.j��{ J DTI P A_y I yas Ilk lot t rya.. Vr� � .3 �1 �f.-_ ^..�_ 1 1 _ �•IY , �� F byrHrvi . K.i I _ fir' '• -- • '7c''' i�. '� <i end m, Rock Creek Lift Station ' '. — Grandview Sewer Gravity Rock Creek Force Main Exist Model Averaged� i .25 0.25-0.35 Y Figure 4 murraysmilh Grandview 0 Odor Control Study Depth a r I l K � ,�. ••��I Salt _ I - • �ae 4kt4f ,.a;,. �r� i�'t -� f ,•_ ` �� [ 1. ,�-,r"'F' - - _-R,.-_.,, J �tF _ '+- • �. y� .4, ` cam`" I � .a�i }M' `j'. .T".)++��p[i� a �t r`Al'�t�� E�� '?- •�t; . . *K . -�r •'L _ ba 14� 'fy M �,-1y.,.. .h X �j ni-_ - Legend I r � f I m Rock Creek Grandview Sewer Gravity — Rock Creek Force Main Committed Model Average Velocity 2 to 4 fps I 1 >8 fps Figure 5 Fmurraypnmith Grandview Odor Control Study Committed Hydraulic �• '+� it ' ,.^ fi,^ - a r j •� i lllttt h�✓at ��c�i5. 1�:. c r+4♦ I `_ _ i �'..<xladta� 1.�'�'SJr.��e a�., -=r =-.{ti •. 4 • - _ ,i�. _ •, _ . - 4jA i l .L Il.r t.. . F. � War d � '•' � a :.,y,• as j - ��iy><P( . i•� t°",�J"nIp F��1 Tn Y��!� e2.G KQ� '�� ..'� � ..�? �.1 n_ - �r +'� L'Ib u'�1•.^.,';4t�"ty i/:rs7*P•�19,nMY"�' S! � f,• X��'t.:,��;t- + :..`, �Ri y l •. ji - • c. ''r - �I Ail f A / �, _I. _ `, i- •.•.fit • � ♦ ,4.-\��•�,5': [A Legend 1. 19 Rock Creek Lift Station Grandview Sewer Gravity Rock Creek Force Main Committed Model Averaged over D 0.25-0.35 1 1 4 0.45 Committed Hydraulic r Odor Control Study Model Depth over Diameter \ ) ' ) ` I \ ' ! , \ . ) . § op, \ , 10 _ { \ / , / ! - \ f | , o \ moo ! - &- iz w ! / . ! � . ! \ ! ! • � { ` : . ! ! ! , / , o � 0 ! \ � ` 0 , ! , . ! ' co § ` 2 , � � / • ¥ , , . R § • ` ¥ . /� , e ; ; 0 y | . R 9 ` ƒ / a / - § - )! co o! !§I &-! . . . , , ; . . . . . . . . . . . . . . . , . ■ . , . ; , , . . . . . . , . ; . , « u! __ ._. / ƒ q � , ! _ � \ � � ; o \ ■ '; � I \ \� i ! ƒ • § . | � ° • CL ( , ! ` � { ` / • 2 ) ' , !. ! ƒ \ • z ` \ \ § \« i : • , - = // } «\«»«e»»§ / neouennn m�mmeom§w mumneneue, j \� • � ! ; , � , 00 / ! ! • � ! , } ^ \ ' \ � • a � . 0 \ . . x A . & � ` . ¥ » • ( ) , X \ , � ` \ J ! r 6 k ! .............1...,..........;,......,.:.,.;..;. . , . , . . . . ,2 ,�. , , . , . . ! . , o ! •-_ ,>murraysmith Technical Memorandum 4 Grandview Odor Control Study — Phase 2 2019 Work — Rock Creek Lift Station City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Background Information Introduction The Rock Creek Lift Station is a part of the Grandview Trunkline in the City of Twin Falls' (City's) sewage collection system. The lift station wet well has experienced significant fats, oil and grease (FOG) accumulation and requires manual removal of the FOG. This memo documents the City's potential options to automatically remove the FOG. Rock Creek Lift Station The Rock Creek Lift Station experiences accumulations of FOG in its wet wells. The FOG creates a thick buildup on the water surface and becomes an operational nuisance and odor generation source. The lift station has four separate wet wells:The old lift station contains two separate wet wells, each 15-feet x 20-feet and the new lift station has two wet wells separated by a slide gate each, 13.5-feet x 5-feet. The lift station operates with a fairly constant water level around 7-feet and typically with two pumps operating. The lift station was inspected by Murraysmith staff with operators present to provide a narrative of operations. As-built drawings were also reviewed. Alternatives The following options were considered for evaluation:oxidizing spray, potable water spray mixing, recirculated wastewater from force main, recirculated water from dedicated recirculation pump, mechanical in basin mixer, course bubble aeration, pulsed compressed air bubble mixing. 17-2122 TM 4 Page 1 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho Oxidant Spray System The oxidant spray system consists of a hydroxyl radical oxidant generating unit and nozzles in each wet well.The oxidant is sprayed from nozzles into the wet wells where it then reacts with fats, oil and grease to break the fatty acid chain. The oxidant can also oxidize sulfide and other odorous compounds. After oxidation, the FOG naturally mixes with the wet well water and is pumped through the lift station. Potable Water Spray Mixing Potable water spray mixing consists of spraying potable water across the water surface of the wet well to agitate the surface. Due to the surface area and size of the wet wells, this will require a large number of spray nozzles and quantity of water to be used at the lift station. Also, potable water is not currently available at the lift station. While simple on the surface, this system will dilute the existing wastewater and will require a large quantity of potable water. Recirculation System Recirculated wastewater from the force main would utilize modulating valves to redirect a portion of the pumped wastewater back to each of the wet wells. This alternative would require a control system to operate the recycle stream, which would need to be carefully controlled so as not to negatively impact the existing pumping operations and is likely the most complicated alternative. Recirculated water from dedicated recirculation pump consists of installing a dedicated submersible pump in each of the wet wells to pump and recirculate flow in each basin. Mechanical Mixing A mechanical in basin mixer would utilize a submerged mixer in each wet well.The mixer will need to be designed for high solids application so as not to become entrapped in rags. Course Bubble Aeration Course bubble aeration consists of providing air to the wet wells with bubble size in the quarter inch to half inch diameter which rise through the water causing mixing action. A blower provides the air for the aeration. Pulsed Compressed Air Bubble Mixing Pulsed compressed air bubble mixing consists of intermittent bursts of compressed air through a nozzle plates at the bottom of the wet wells.These bursts of air are quite large and create a rolling mixing patter around the bubbles. A compressor is used to provide air for this application. 17-2122 TM 4 Page 2 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I:'\130I_Projects'v,17\2122-Twin Falls Grandvnew Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Work14 Rock Creek Lift Station\TM-Fall P2 4_03.112021.docx Cost Estimation The top two most viable options were further developed in a conceptual design: oxidizing spray and dedicated recirculation pump. The total project cost estimates include costs for material, labor, equipment, mobilization/demobilization, overhead and profit, traffic control, erosion and sediment control, bonds, insurance, contingency for unforeseen items, engineering and administration costs. All costs cost estimates are high level preliminary engineering Class 5 AACEi cost estimates in 2018 dollars. Table 1 Vapor Phase Treatment Summary Treatment � . Conceptual Concept .. ■ Potable Waterline to Lift Station ■ Oxidant Generation System Oxidant Spray System Nozzle Spray System $376,000 ■ Power, Electrical, Instrumentation and Control Integration ■ Submersible Pump, Nozzle and Rail Internal System X4 $235,000 Recirculation ■ Power, Electrical, Instrumentation and Control Integration Recommendations Based on this study, Murraysmith recommends the following future tasks: ■ Rock Creek Lift Station FOG Control o Complete a pilot program and feasibility study of Oxidant Spray System for FOG control. o Complete design and construction of system to control fats, oil and grease at the Rock Creek Lift Station which have led to operation/maintenance problems and odor generation at the lift station in the past. 17-2122 TM 4 Page 3 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I.\BCI_Projects'v,17\2122-Twin Falls Grandvnew Odor\Phase 2\Task3 45 Sampling Alt Eval Results\Memos 2019 Wo66,4 Rack Creek Lift Station\TM-Fall P2 4_03.112021.docx murraysmith Technical Memorandum 5 Grandview Odor Control Study — Phase 2 2019 Work — Condition Assessment City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Introduction The purpose of this task is to complete a high-level assessment of the condition of the Grandview Sewer Trunkline pipeline and manholes and associated rehabilitation and/or replacement costs. These cost estimates can then be used by the City to help select odor and corrosion mitigation measures and gauge the appropriate level of investment. City staff have noted the advanced state of corrosion of the manholes concrete and cast-iron components throughout the Trunkline. Condition Assessment Table 1 summarizes the Grandview Sewer Trunkline pipe segments. Based on available data, the City believes that all pipe material in the Grandview Trunkline is plastic and in good condition. There are 103 manholes along the Grandview Trunkline with approximately 890 total vertical feet (rim to invert). Most of the manholes are concrete in various states of corrosion and degradation. There are some manholes that are lined with a precast liner, are polymer concrete, and have other corrosion resistant methods. The cast iron frame and covers are rusting, corroding and in various states of decay. Some of the manholes have had composite frame and coves installed due to corrosion of the original cast iron. 17-2122 TM 5 Page 1 of 3 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho Table 1 Grandview Sewer Trunkline Summary Pipe Diameter Length Number of 12 234 3 16 80 3 18 2,304 6 21 872 2 24 388 3 27 408 1 30 51200 20 36 16,671 51 42 2,826 11 48 1,277 2 Total 30,260 102 Cost Estimates This desktop review of the existing Trunkline was used to generate conceptual costs estimates to both conventionally replace and rehabilitate the Trunkline to make it more resistant to the existing corrosion conditions. The City should confirm that all the pipe along the Trunkline is plastic and replace or line any concrete or other material pipe segments. Manholes should either be replaced for rehabilitated. Replacing manholes consists of bypassing flow around manholes,excavating and replacing the manhole with new components. The City should also consider any replacements be completed with corrosion resistant manhole materials such as including polymer manholes, composite frames and lids. Rehabilitation of concrete manholes could include a mix of spray on liner application, polymer manhole inserts, cured-in-place manhole and composite frame and lids. Total project cost estimate for each option are summarized in Table 2 and 3. 17-2122 TM 5 Page 2 of 3 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\BCI_Proje^_ts'',17\2122-Twin Falls Grandview odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Memos 2019 Work\5 Condition Assessment and Value ATM-Fal I P2.5 CondAssess_03.11.2021.do`x Table 2 Grandview Sewer Trunkline Pipeline Project Cost Estimate Summary Pipe Diameter Length - • r- • Project •,t Project Cost 12 234 $72,000 $41,000 16 80 $27,000 $18,000 18 2,304 $814,000 $544,000 21 872 $331,000 $231,000 24 388 $333,000 $240,000 27 408 $179,000 $131,000 30 5,200 $2,437,000 $1,791,000 36 16,671 $8,998,000 $6,569,000 42 2,826 $1,758,000 $1,248,000 48 1,277 $915,000 $623,000 Total 30,260 $15,864,000 $11,436,000 Table 3 Grandview Sewer Trunkline Manhole Project Cost Estimate Summary Type Total Projectcost Average Project Cost per • Replacement Manhole Conventional $3,050,000 $29,600 Replacement Manhole Corrosion Resistant $3,570,000 $34,700 Polymer Insert Rehabilitation Manhole $2,248,000 $21,800 Cured-in-Place Manhole $2,068,000 $20,100 Spray-On Liner $946,000 $9,200 17-2122 TM 5 Page 3 of 3 Grandview Odor Control Study—Phase 2 Results March 2021 City of Twin Falls, Idaho I.\BOI_Proje^_ts'',17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Nlemos 2019 Work\5 Condition Assessment and Value;TPd-Fal I P2.5 CondAssess_03.11.2021.do`x murra smith ,Y � Technical Memorandum 6 Grandview Odor Control Study — Phase 2 Conclusions, Recommendations and Improvements City of Twin Falls, Idaho Date: March 17, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Introduction This memorandum presents the studies conclusions, recommendations and proposed improvements for the Grandview Sewer Odor Control Study. Liquid Treatment Conclusions The liquid treatment analysis provided discussion on various liquid treatment options to mitigate liquid phase sulfur compounds that contribute to odor and corrosion issues in the Grandview Trunkline (Trunkline). The magnesium hydroxide pilot was not effective in treating the odors in the Trunkline. Ferric chloride was partially effective in treating the odors during jar testing. Vapor Treatment Conclusions The results of sewer review and modelling were used to select locations for potential installation of five vapor phase treatment systems. Three separate headspace areas of trunkline effectively exist due to a full pipe flow at the Rock Creek siphon crossing and the Rock Creek Lift Station. For this study, the Upper Grandview Trunkline Area is defined as upstream of the Rock Creek Siphon (MH C5-21),the Middle Grandview Trunkline Area is from Rock Creek Siphon to Rock Creek Lift Station (MH C5-3 to Rock Creek Lift Station) and the Lower Grandview Trunkline Area is from Rock Creek Lift Station Force Main Discharge to Canyon Rim (MH 134-102 to MH 131-8). The most likely vapor phase treatment locations are summarized in Table 1. 17-2122 TM 6 Page 1 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho Table 1 Vapor Phase Treatment Summary Grandview Trunkline Extraction Distance of Area of Grandview Area Manhole Influence Influence Trunidine (feet) Area Lower B1-4 7,500 B1-4 to B2-3 Lower Lower 133-1 8,830 B2-3 to B3-13 Lower Lower B4-1 2,630 B3-13 to B4-5 Lower Middle 64-7 7,480 B4-7 to C5-3 Middle Upper C5-177 1,290 C5-177 to C5- Upper Rock Creek Lift Station Conclusions The Rock Creek Lift Station experiences accumulations of fats, oils and grease (FOG) in its wet wells.The FOG creates a thick buildup on the water surface and becomes an operational nuisance and odor generation source. Memo 4 recommends pilot and installation of Oxidant Spray System for FOG control. Grandview Trunkline Conclusions The Rock Creek Lift Station experiences accumulations of fats, oils and grease (FOG) in its wet wells.The FOG creates a thick buildup on the water surface and becomes an operational nuisance and odor generation source. Memo 4 recommends pilot and installation of Oxidant Spray System for FOG control. Recommendations Based on this study, Murraysmith recommends the following future tasks: ■ Complete ferric chloride pilot treatment ■ Vapor phase treatment at key locations of the Grandview Trunkline— Due to the high capital cost of the to ventilate and treat the headspace of the Grandview Trunkline, it is not recommended that the City pursue vapor phase treatment. ■ Rock Creek Lift Station FOG Control o Complete a pilot program and feasibility study of Oxidant Spray System for FOG control. 17-2122 TM 6 Page 2 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I:\BOI Projec-s\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Alt Eval Results\Memos 2019 Work\6 Options and Recommendations\TM-Fall P2.6 Options and Rec 03.11.2021-doa o Complete design and construction of system to handle fats, oil and grease control at the Rock Creek Lift Station which have led to operation/maintenance problems and odor generation at the lift station in the past. ■ Inspect and assess the corrosion damage to pipe along the Grandview Trunkline: o Pipeline CCTV condition assessment—Confirm pipe material and condition at a minimum. ■ Begin manhole rehabilitation program: o Manhole condition assessment— Field confirm material, condition and size. o Prioritize repair, rehabilitation and replacement of manholes. 17-2122 TM 6 Page 3 of 3 Grandview Odor Control Study March 2021 City of Twin Falls, Idaho I:\BOI Projec-s\17\2122 -Twin Falls Grandview Odor\Phase 2\Task 3 4 5 Sampling Alt Eval Results\Memos 2019 Work\6 Options and Recommendations\TM-Fall P2.6 Options and Rec 03.11.2021-doa murra sm�rth y � Technical Memorandum Grandview Odor Control Study Ferric Chloride Pilot City of Twin Falls, Idaho Date: March 10, 2021 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 To: City of Twin Falls, Idaho From: Murraysmith Introduction This memorandum documents the evaluation of the Ferric Chloride Jar Testing, Liquid Sulfur Testing, and Ferric Chloride Chemical Treatment Pilot Testing for the Grandview Trunkline (Trunkline). The purpose of the Ferric Chloride Chemical Treatment Pilot Test (Pilot) was to determine the effect of the addition of ferric chloride on the sulfur compounds found in the Trunkline through jar testing and pilot testing. Project Background The Trunkline is a major part of the City of Twin Falls' (City's) sewer collection system and has historically had citizen complaints due to odor. Additionally, the Trunkline's concrete manholes, cast-iron frames and lids are in varying states of decay due to corrosion. The Trunkline stretches over 5 miles from the canyon edge along Canyon Rim Road, Grandview Drive, Filer Avenue, cross- country pastthe Country West building, down into Rock Creek and south along Washington Street, seen later in Figure 4. Given the nature of the odors observed, it was determined that the highest contributor to the odors was likely Hydrogen Sulfide (HZS) gas. Any concentration of HZS will degrade concrete, however, a typical goal is to keep concentrations of HZS below 5 parts per million (ppm) in the sewer headspace. For comparison to the results presented later in this memorandum, a range of Hydrogen Sulfide gas detection and exposure threshold are described below: ■ 0.00047 ppm: Human odor threshold ■ Less than 10 ppm: Irritation of eyes, nose, throat and respiratory system 17-2122 Page 1 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho ■ 10-50 ppm: Headache, dizziness, nausea, coughing, vomiting and difficulty breathing ■ 20 ppm: OSHA acceptable ceiling concentration ■ 50 ppm: OSHA acceptable maximum peak with a maximum duration of 10 minutes if no other exposure occurs during an 8-hour shift ■ 50-100 ppm: Eye injury can occur ■ 100-300 ppm: The olfactory nerve is paralyzed after a few inhalations and the sense of smell disappears ■ 300-500 ppm: HZS reacts with water in lungs to form acid which can cause pulmonary edema ■ 500-1000 ppm: Strong effect on central nervous system and causes respiratory system to shut down ■ 800 ppm: lethal concentration for 50% of humans for 5 minutes of exposure (LC50) ■ 1000 ppm: Immediate collapse, even after inhalation of a single breath, and death within minutes The above concentrations present an increased danger in confined spaces, such as the headspace of a manhole. Confined spaces are areas with limited or restricted means of entry or exit, are large enough for a person to enter, and are not designed for occupancy. Examples of confined spaces include vaults, pits, tunnels, pipelines, and tanks. Additionally, headspaces, such as those found in manholes, tend to collect HZS gas due to a lack of airflow. Phase 1 Overview Phase 1 of this project included initial sampling of liquid and vapor phases in the Trunkline to determine the location and extent of the problem areas. The name, date and introduction of the Phase 1 memorandum is below. This memorandum is included in Appendix 1. Grandview Odor Control Study, March 15, 2018 This study included collection system sampling, both liquid and vapor phase, to help delineate and quantify problems areas along the Trunkline. This study was the first phase of the project. Phase 1 concluded the Trunkline sewer has odorous wastewater along the entire alignment, conditions are ripe for generation of corrosion of the collection system, and the existing concrete components have severe corrosion. Recommendations provided as part of Phase 1 included the evaluation of hydrogen sulfide management alternatives, liquid phase treatment pilot, vapor phase treatment pilot, Rock Creek Lift Station Fat Oil Grease Control, and the assessment of the sewer system damage, all as part of Phase 2. 17-2122 Page 2 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1'\B0I_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa Phase 2 Overview The Phase 2 Study was the second phase of the study and project to control odor and corrosion in the Trunkline. Within multiple memoranda, this phase included collection system condition data collection, refined collection system sampling (liquid and vapor phase), evaluation of vapor phase and liquid phase treatment options, and development of solution alternatives with associated capital and life cycle costs estimates.The name, date and introduction of the phase 2 memoranda are below. These memoranda are included in Appendix 2. Technical Memorandum 1, 2019 Work—Introduction, September 30, 2020 This memorandum provides an introduction to the Trunkline and the project. The Grandview Trunkline generally flows from south to north and collects from a large portion of the City's sewage collection system.The Grandview Trunkline begins near the intersection of Washington Street and Highland Avenue and continues north to Canyon Rim Drive. The pipes in the Trunkline are 18-to 48-inch in diameter and there are approximately one hundred manholes along the Trunkline. The City's Rock Creek Lift Station is located approximately one third of the way down the Trunkline. The lift station pumps sewage from an area down in the Rock Creek Drainage up to an area just west of County West buildings where flows can then proceed by gravity all the way to the wastewater treatment plant (WWTP). There are four permitted industrial wastewater dischargers in the southern portion of the Grandview Trunkline: Glanbia Nutritionals, Lamb Weston Inc.,Aramark Uniform Services(formerly AmeriPride Linen and Apparel Services), and West Rock (formerly Kapstone Container Corporation). Technical Memorandum 2, 2019 Work—Liquid Treatment, September 30, 2020 This memo documents liquid phase collection system condition data collection and evaluation of liquid phase treatment options. Liquid phase testing showed that in general, the sulfide concentration is higher in the upstream portion of the Grandview Trunkline in the Washington Street Industrial Area (shown in a figure later in this memorandum). Liquid treatment options presented included biological and chemical and the memorandum described their general treatment method and other information. Jar testing of several possible chemicals for treatment was also completed with varying results. A magnesium hydroxide pilot for pH control of wastewater in the Trunkline was completed and shown to be ineffective. Pilot chemical treatment using ferric chloride was recommended in the Trunkline system. Technical Memorandum 3, 2019 Work — Vapor Phase Investigation and Treatment, September 30, 2020 This memo documents the vapor treatment collection system sampling, evaluation of vapor phase treatment options, and vapor phase headspace airflow evaluation. Vapor phase treatment is anticipated to be beneficial to address localized odor problems and multiple installations were 17-2122 Page 3 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1,\B0I_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa recommended. The trunkline is physically separated into three headspace areas and each will need its own vapor phase treatment system(s) to holistically treat the trunkline headspace. The results of the sewer review, modelling and headspace pressure monitoring were used to select locations for potential installation of five vapor phase systems. Technical Memorandum 4, 2019 Work—Rock Creek Lift Station, September 30, 2020 The Rock Creek Lift Station is a part of the Grandview Trunkline in the City of Twin Falls' (City's) sewage collection system. The lift station wet well has experienced significant fats, oil and grease (FOG) accumulation and requires manual removal of the FOG. This memo documents the City's potential options to automatically remove the FOG. Technical Memorandum S, 2019 Work—Condition Assessment, September 30, 2020 The purpose of this task was to complete a high-level assessment of the condition of the Grandview Sewer Trunkline pipeline and manholes and associated rehabilitation and/or replacement costs. These cost estimates can then be used by the City to compare to the cost of odor and corrosion mitigation measures and gauge the appropriate level of investment. City staff have noted the advanced state of corrosion of the manholes concrete and cast-iron components throughout the Trunkline. Technical Memorandum 6, 2019 Work—Conclusions, Recommendations, and Improvements, September 30, 2020 This memorandum presents the 2019 Work Memoranda conclusions, recommendations, and proposed improvements for the Trunkline. Major recommendations included discontinuation of vapor phase treatment evaluations, Rock Creek Lift Station FOG control pilot, inspection and assessment of the corrosion damage to pipe along the Trunkline, a manhole rehabilitation program, and a ferric chloride chemical treatment pilot. Ferric Chloride Odor Treatment Ferric chloride (FeC13) is an iron salt which, in the presence of hydrogen sulfide (HZS) in solution, produces a chemical iron-sulfur precipitate that permanently removes the sulfur from solution. This effectively eliminates future odorous and corrosive sulfur compounds from being produced. Ferric chloride is often used in wastewater treatment and will also remove phosphorus from wastewater. The dosage of ferric chloride is dependent on water chemistry and sulfide (SZ-) concentration and will produce a sludge (greater than 3 pounds sludge per pound sulfide)that will travel through the collection system. The theoretical dose of ferric chloride is 1.2 pounds (lb) Fe3+ per lb HZS with practical dose rates anywhere from 1.5 to 4 lb Fe3+ per lb HZS depending on the application and water chemistry. Ferric chloride costs can vary regionally and seasonally and are very dependent on local sources of supply. Treatment is hydrogen potential (pH) dependent and it is hard to achieve low sulfide limits. Optimum pH for ferric chloride treatment is around 8, which is similar to the pH in the City's sewer system. The application of ferric chloride also lowers pH, 17-2122 Page 4 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1,\B0I_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa which can cause any non-precipitated HZS to more easily volatilize in the collection system. Ferric chloride should be handled, stored, and used carefully as it can be an environmental hazard. Jar Testing Prior to Pilot Considering the various studies provided for the Trunkline it was decided that the Washington Street Industrial Area should be the focus for potential chemical treatment as the sulfur compounds found in this area were typically higher in concentration.Samples were collected from an industrial discharger in the Washington Street Industrial Area which featured high concentrations of sulfur compounds in its waste stream. In order to show efficacy of treatment of sulfide with ferric chloride and determine the optimal dosage for the pilot system, the samples were subjected to jar testing with ferric chloride. Jar tests were setup with dosages of ferric chloride ranging from 0 (control) to 200 milligrams per liter (mg/L). The samples were mixed with the varying doses of ferric chloride and were sent to Magic Valley Labs (Lab)for analysis (using the listed EPA methods) to determine the residual concentrations (in mg/L) of: ■ Sulfide (Sz-) EPA 376.2; ■ Sulfate (S042-) EPA 300.0; and ■ Sulfite (S032-) EPA 377.1. The results of the seven initial jar tests are shown in Table 1. Table 1 Ferric Chloride Jar Testing Results FeCh D. r 0(control) 0.81 214 <10 10 1.00 206 <10 25 103 233 <10 50 0.73 218 <10 75 0.69 192 <10 100 0.52 213 <10 200 0.14 198 <10 As shown in Table 1, the potential for treatment using ferric chloride concentrations of sulfide are reduced effectively with ferric chloride concentrations of 50 to 200 mg/L. Sulfate was not removed during the jar testing of ferric chloride. Figure 1 shows the results of the ferric chloride jar testing graphically. Based on the jar testing, 50 mg/L is considered the minimum dose and additional dosing beyond this amount increases treatment. 17-2122 Page 5 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1'\BOI_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa Figure 1 Ferric Chloride Jar Testing Results •Sulfide •Sulfate 1.2 V 250 • 1 � • • • • • i_ 200 0.8 E • • 150 E 0 10 100 0.4 in 50 0.2 • 0 0 0 50 100 150 200 250 Ferric Dose(mg/L) Ferric Chloride Pilot Test The pilot test was setup in the upstream portion of the sewer collection system at the south end of the Washington Industrial Area. The pilot chemical was fed through tubing into the sewer downstream of the Glanbia Nutritionals facility effluent flume but upstream of the Public Works Yard Manhole (C5-32). This location was selected as the chemical feed point because this is at the upstream end of the Washington Industrial Area. Ferric chloride (38% strength) was supplied in two 300-gallon totes and was pumped directly into the waste stream at an initial approximate flow rate of 75 gallons per day (200 mL/min) which is equivalent to 50 mg/L dose rate at an expected average facility discharge flowrate of 0.6 million gallons per day (mgd). The recorded facility average daily flow rate during the pilot was approximately 0.65 mgd, with a minimum and maximum flow rate of 0.11 and 0.88 mgd, respectively. A graph of the instantaneous flow rate at the pilot study location during the pilot, is shown in Figure 2, along with calculated chemical dose, and daily averages of flow and dose. The chemical feed pump stroke rate and stroke length were set to provide the correct dosage at the expected average flow. The totes were stored over secondary containment units and the setup was secured with a temporary chain-link fence. The system is shown in Figures 3 and 4. The pilot test began at 9:25 a.m. on Tuesday, August 25, 2020, and was conducted until the total volume of ferric chloride was expended at some time between late August 31 and September 1, 2020. The 50 mg/L dose rate was selected as the pilot dosing because it was the minimum rate that showed a decrease in sulfide during jar testing and allowed 17-2122 Page 6 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1'\BOI_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa enough chemical to be stored on site using totes for a one-week pilot test. In the future, a full- scale system could be constructed with variable pumping capacity, sensors and a control system that can dose at an optimized amount. As can be seen in Figure 2, the flow rate at the pilot is cyclical with daily peaks exceeding 0.85 mgd and low flow periods of about 0.15 mgd lasting for approximately 1 hour each morning. This variability in the flow meant that dosing concentration varied as well. The average dose during the pilot was about 49 mg/L with high and low dosing at 266, and 32 mg/L, respectively. 17-2122 Page 7 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1'\BOI_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa o -° (l/2W)'3UO o� p p a V vp 8 Or 8 O = rV N .--I .--I In O c O co 0 LL a in U 0 L L.L. A2 p V N N m I 0 I c 0 t a p 'n N N 0 I 0 I o � N op- C ry p � d N N rc O O o s m a N > 00 a E � w ra O ry p J 0 o N f6 3 ry o o s 000 a v s o I) O CD a v o 3 a--+ O n oo I Q O p I �v v 4 s A o E 3 vVi 3 = O u` L.L. W C = O o N O ti (� I 1 m cc Ln m N .--I O ` N G O O O O O O O O O CO N N v N = p (POW)nn01 j N nl I� m m LL d rI 2 Figure 3 Ferric Chloride Pilot System Photo 11 t i c I 1. Photo dated August 24,25-10 17-2122 Page 9 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho I\BOI_Projects\17,2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Aft Eaal Results\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pilot_3.102021.doct Figure 4 Ferric Chloride Pilot System Photo 21 UN25B2 , 11 _� 1. Photo dated August 24,2020 Pilot Test Data Acquisition, Sampling, and Lab Testing Liquid Sampling and Lab Testing Liquid sulfur testing was completed prior to the ferric chloride chemical treatment pilot to locate potential point sources of high sulfur concentrations discharging to the Trunkline. Additionally, liquid-phase testing was completed before,during and after the pilot to quantify the effects of the addition of ferric chloride into the sewer system on the liquid concentration of sulfur compounds. Over a period of a year, from November 2019 to November 2020, approximately 120 samples were taken from the sewer system and tested to determine the various concentrations of sulfur compounds, including, sulfide (S2-), sulfate (S042-), and sulfite (SO32-). An additional two samples were taken from the City's water system and within other parts of the sewer system to develop background sulfur compound concentrations. 17-2122 Page 10 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1,\B0I_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Resuits\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa The following locations were subject to the liquid sulfur testing (see Figure 4): ■ Aramark (formerly AmeriPride) ■ Hospital Pad Manhole B4-4 (collection system location) ■ Glanbia Nutritionals ■ Canyon Rim Manhole B1-28 ■ Lamb Weston— UASB Discharge (collection system location) ■ West Rock (formerly Kapstone) ■ Public Works Manhole C5-32 ■ Will's Booster (City Water—Control) (collection system location) The results of the liquid sulfur testing are shown in Table 2 and are summarized below. The pilot location was between the Glanbia Nutritionals discharge and the Public works Yard manhole. There are no notable other sources of discharge between these locations and the distance between the two monitoring locations is relatively short, therefore, the measured concentrations between the locations would be expected to be similar when measured simultaneously. It was observed during the pilot, that the average concentration of sulfide was effectively reduced by approximately 54% from the Glanbia discharge to the Public Works Yard manhole. It is worth noting that the average sulfide concentration at the Glanbia Nutritionals discharge prior to the pilot and during the pilot are similar, indicating that the loading of sulfide is also similar. Sulfate also decreased which was not expected. This could be due to bacterial metabolism transferring the sulfur from sulfate to sulfide. The City's domestic water supply was also tested for sulfur compounds to establish the background concentrations.The average sulfate concentration in the City's water supply is around 64 mg/L. Recently, Aramark ceased the use of Sulfuric Acid as a pH stabilizer. This likely will help in decreasing amounts of sulfur compounds in their waste stream. Aramark does not discharge directly to the Trunkline but in another area of the sewer system that eventually joins with the Trunkline. 17-2122 Page 11 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1'\BOI_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Resuits\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa ' V+ � � t• r '%fin ( nil - tr 1 6.0 4 -j �i+ yi�, r��IMrpp,.,�y,'Y1 ql ems. 11��i�' - �=��C�•-y-.+~ -- �':j-." , .. r �'i � �M� � � lr��.�a43�, t_l *.j::3�;1•-. ! '•�F��I � � .� +a-• SGr�I +0 (ye ` �' = l .•�y�.•+�' ��•K-s'9t.+-� Yy•.`�,� =t.,�,. a•.,�•.;C71L I..`.1 a,� �,�r_ r�Xa: Y^��t`'�y�1,:. :. ;,` fie•.'_-_- !� - -; � :L��.�'.r�.<l �i F 't�'�y�"' .�'. + f � P•• �,,''4 yam.�� , - Creekreek Lift Station ran view Sewer Trunkline Rock - in Grandview Odor Control Study Figure 5 O 0 L 01 � o `o m O Z V C ` v`o E X ° ^MV o oo 00 o Nao oCL " o o 0 E E M O O i N N O i ID 0 Ln Y a, n N N 'Or N O 00 p o, � N e-I v wvu, va .n v . .. . . . .1 0 z E Eu00 ° o ° Nomvo ago o s c o E E ury o o 0 o . . . . . , , Wco 00 Q � m 0 M ti ~ M M M N N N V� Vl Vl 0000 00w0 i0 N N N 00 O i O Z E Ei. ao � N oavm v ci ^ n n 6 N ti Ol p .-i •-� O Vt M O .--I OJ W p l0 O a d a ECD v N Y LO E O N M O N M ti Q O N O p O O N O p ry } E O O O O O O O Ln m .�-1 1f1 M ry r .�-I W .N-� Vt M N M M O Q > .--I N l0 •-1 00 � ry N O W p I� O l0 Q O V Q O vl O Q N O 0 O Q v O- O u o v .-... d v Vl N V v N v � C O -O O! N v 0! 'O O) N 'O OJ a N LL o io a+ io .• `� is .+ `� io ,..� io 2 w `� o 0 w w w w w w w w w S w w o v1 VI v1 N v1 V7 V1 Vt N N Vt v� V1 Vl Vf Vl DJ E z a�z 0 o L u E i o 0 L E d. " v 'Y v O Y Q Y �' p v m ,,�, E E E N 2 2l O 0 0 t>o a' 3 m S g OJ N L N 00 ic a �' E E x u u z a' E m o a .0 x 8E Y e 2�Q Q 3 E tt�— ° E vvpE � � �v (v N 00 z V w��z a y N 7 U -+rvniv ui�ti N ` Vapor Phase Testing Vapor phase testing was setup to quantify the effects of the addition of ferric chloride into the sewer system on the sewer headspace HZS concentration. App Tek International Acrulog HZS loggers (Odaloggers) were placed in the headspace of manholes along the Trunkline to measure concentrations of HZS,see Figure 6.The Odaloggers were placed in the following collection system manholes (upstream to downstream): 1. C5-32— Public Works Yard Manhole 2. C4-7— Rock Creek Trail Above UASB Discharge 3. C4-4— Rock Creek Trail Below UASB Discharge 4. B4-5— Hospital Pad 5. B1-47—Canyon Rim 6. C1-199—Aramark Discharge Odaloggers were placed in the manholes and were recording prior to the Pilot test, throughout the Pilot test and at least for one week after the Pilot test concluded. Graphs of Odalogger data are presented in the next section. 17-2122 Page 14 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls,Idaho _ 1!!��' �� ,., Fc3 �a9 �I�`'!}�� ,�° ,..y yr ri\.i � ..- .1 II � ^. • yY d iJJr Al !'�`, i{�� - F fry w� I,ti^ -ate, . .+ � -i~�■�:�,� I • - .r' j� ,. r� s i h' ,i'� -� 1`".4 4� s `i..�•'i !'�y � '}. fir. .�J •ate. ` � "� Y � 1 - .1. yl�JJ...+.�a "fi'"i fiJ•' J y �:i•-�* +,�„Y + ;,3�"Id 1: ��;�L1 �-"��, � , � {~ � ��!!��t }E�^ �.xx��y, Y�I�j��p,s�f 'a�l1��a��''I�T,,k.ri ,• ' r r�y r &Alie y Lamb Weston C4-7 Rock r <* v s. Ocalogger Location Glanbia Nutritionals Grandview Sewer Trunkline Grandview Odor Control Study Figure 6 Odalogger Data Results from the Odaloggers that were placed in the manholes are shown in Figure 7 and 8. Figure 7 presents all data collected in 2020. Occasionally, the Odaloggers must be removed from the sewer collection system and these times are shown as flat lines in the figure. Figure 8 presents data just before, during and after the pilot. Individual graphs for each record can be found in Appendix 1. Figure 7 and 8 show high variability within the data with 'spikes' of high H2S concentrations ranging from 100 mg/L to almost 800 mg/L. Spikes in concentration can be caused by changes in water constituent concentration, and changes in hydraulics with associated airflow dynamics. The spikes are not sustained indicating potential discharges of high strength loading. The time periods for the high and low variations typically last for two or three days. Additionally, a general decrease in concentration can be seen from upstream to downstream. Figure 7 shows that during that during the pilot there was an apparent reduction in HZS sewer headspace concentrations as measurements made during this period are typically under 50 mg/L. Since liquid phase concentrations at the Glanbia Nutritionals discharge (discussed in the Liquid Sampling and Lab Testing section) prior to the pilot and during the pilot were similar, it is anticipated that the liquid phase loading during the pilot is consistent with the historical measurements. This means that during the pilot, it is anticipated that there were wastewater constituents that would react with the ferric chloride. 17-2122 Page 16 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls, Idaho 1,\B0I_Projects\1712122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Resuits\Task Force\Ferric Pilot 2 week 2021\Memo\TM-Ferric Pdot_3102021.doa 0 o ti - 0 70 V 0 0 0 N ,l L s _ � U �C}} U 7 V � ON LaL 0 N O rN O rV O N 1 N C) O N O ----------------------------- N ----------------------------------------- cv O N n 0000 O N O N m 0 N 0 N 61 00 o 0 o 0 0 1 N o Qj co a a N 0 N 0 N a; m rn fa — �t o 0 0 0 a, m m N o a � a O .n 0 ; o Q m Y F H m Y Y N Y N N d o a N V U U 0 E Q >C Y p c 3 V V N Q O cc ccS V Ol 9 C N N N N 0 N W m ^ N 0 p p N N U v a co co � a a oN N - 01) 0 v O O \ N v a 8 8 0 8 8 8 8 8 r,4 o (l/2w)SZH N v LL 0 0 0 0 N d o N v — 0r `—^ O m `0 i0 :E LL C m U . t u 3 Ln � F p O v� O t a rN LL O � c D D o, U m o o a� -o -0 a) 0 m Q m 8 = o -o E t Y Y m � Y ai a� a - .2 v c m U U +' 0 E -0 u u m Q o K 2 U c a O +� m tY1 I� V� �f1 er a-I O O Qt U U U m m U m 'a ° N m o 0 o � ------------------------------------------------- ------------------------------ - O c N --------------------------------------------- 00Q1 F y o @ O u 0 00 31� 0 a) o m d0 N �6 E O 3 ------------------------------------------------- CD `u O n 0000 O ----------------------------------------------- O uri a N eo 00 c 00 a E �n 0 N c O O m a o to o c o CN L 0 3 U ELM Q � C V 00 -_ C Q 0 3 N L O N 00 t rN oo 8 8 8 8 8 8 8 8 o O 00 n to Lf1 v rn N ,-� 00 N N u L N GA (1/?w)SZH a N U b IL 0 c-1 C Table 3 shows the average concentrations of HZS for all of the measurement manholes, before, during, and after the pilot test. Table 3 Ferric Chloride Pilot Vapor Phase HZS Results' Date Range Description 8/19-8/25 Pre-Pilot 11, 5 31 51 e 3 " 2 8/25-9/1 During Pilot 2 2 15 101 0 9/1-9/9 Post-Pilot i 1 1 5 4 1 Note: 1. Average HZS Concentrations in mg/L. The historical HZS concentration in the headspace of the Trunkline is highlyvariable as seen before, during and after the pilot.Additionally, numerous factors influence the vapor phase concentration of HZS. Therefore, making direct pilot efficacy conclusions from the vapor phase average results alone is not possible. Special Note At two times during the pilot test,the metering pump lost its siphon which caused the pilot system to stop applying ferric chloride to the sewer system. The first time this happened, it appears that the concentrations of HZS were essentially unchanged. As discussed previously, the HZS concentration in the Trunkline is highly variable, and the loss of chemical feed likely occurred during a period of low HZS in the collection system. However, the second time this happened, concentrations of HZS spiked in manholes C4-4 and 134-5. The maximum HZS concentrations that these manholes experienced at this time was 314 and 305 mg/L, respectively. After the system was reactivated the second time, HZS concentrations were observed to decrease to below 20 mg/L very quickly. This is attributed to the effect of the pilot chemical application. Conclusions Jar testing showed that treating the Washington Street Industrial Area wastewater samples with ferric chloride concentrations of 50 to 200 mg/L of ferric chloride is effective in reducing the concentrations of sulfide 10 to 83 percent, respectively. The ferric chloride pilot with 50 mg/L ferric chloride shows that the introduction of the chemical into the Washington Street Industrial Area is effective in reducing the concentrations of HZS in the Trunkline as evidenced by the liquid and vapor phase HZS monitoring. Long-term chemical treatment of the Grandview Trunkline with ferric chloride will reduce the concentration of odorous hydrogen sulfide and provide a level of protection from corrosive conditions in the sewer. For long-term treatment, the amount of ferric chloride introduced into the Trunkline should be optimized and HZS monitored to ensure that the correct dose is used.This could lead to periods of higher and lower chemical dosing. 17-2122 Page 19 of 19 Ferric Chloride Pilot March 2021 City of Twin Falls,Idaho murraysm��l� Technical Memorandum Grandview Odor Control Study — Phase 2 Smoke Testing City of Twin Falls, Idaho Date: December 14, 2020 Project: City of Twin Falls: Grandview Odor Control Study Phase 2 0 lo: City of Twin Falls, Idaho �� ,�► From: Murraysmith Introduction This memorandum documents the events of the smoke testing on the Grandview Trunkline (Trunkline) on October 7, 2020. The purpose of the smoke testing was to provide a localized condition assessment for a frequent odor complaint location along the Trunkline. Testing Location The location determined for the test was an area of the trunkline between Russet Street and Shoshone Street South and north of South Park Avenue West, before the gravity siphon under Rock Creek. The manholes used for the test were as follows: • C5-21; and • CS-177. Figure 1 shows the testing location. 17-2122 Page 1 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho OF 'r R w_ - r, °J S _ - 0 Y .,K fro ` C5- --- 5-,177 NI � - outh Park Avenue West • i AV Avg a • o w m , . � L • N r Legend � • Blower Test Manholes • Grandview Sewer Manholes ' Grandview Sewer Trunkline -- 0 250 Feet Gravity Sewer VI a�GeoEye„Earthstar Geographms CNESAirbus DS-l=1SDA USGS --- -- �onm ty ' �11:f91i.s Grandview Odor Control Study Figure 1 't'N _ m murraysmith -I- Smoke Testing Test Location Smoke Test The smoke testing took place on October 7, 2020. The smoke testing was provided by Sweet's Septic Tank & Backhoe Service Inc. (Sweet's). Procedure Notification Before the smoke testing took place, the City provided letters and "doorhangers" to customers who may experience instances of smoke during the testing. The letter and doorhanger are attached in Appendix 1. Additionally, notification was sent to the City's emergency responders including the Twin Falls Fire Department, Twin Falls Police Department, and Twin Falls Dispatch Office, informing them that smoke testing would take place and that they may receive calls reporting smoke around the two testing locations. The City also provided a notice on the City website, including a Frequently Asked Questions (FAQ), informing the public of the smoke testing. The FAQ is also attached in Appendix 1. Equipment Sweet's provided smoke testing via two manhole-placed blowers. The larger blower was a Hurco Super Power Smoker which has a 5.5-HP engine and approximate capacity of 8,760 cfm. The smaller blower is a Hurco Super Smoker 2 with a 2.5-HP engine and approximate capacity of 700 cfm. Figures 2 and 3 show the manholes and blowers that were utilized for the tests. The smoke was provided by a liquid smoke solution (LiquiSmoke by Hurco) that when introduced to blower exhaust, creates a non-toxic white smoke which is then blown into the sewer.The Safety Data Sheet (SDS) for the liquid solution and an independent analysis of the smoke byproduct is included in Appendix 2. Setup The two blowers were placed on manholes to force smoke to in the sewer collection system. Testing Each blower was activated, and smoke was applied to the sewer system. Smoke was emitted into the sewer system until positive occurrences of smoke were observed emanating from surfaces, structures and/or buildings. Smoke was continuously blown into the system until relevant instances of smoke could be documented. Each instance of smoke was noted, pictures were taken, and if required, further investigation was undertaken to locate the source of the individual smoke occurrence. Smoke emanating from roof vents above building rooflines is normal and anticipated to occur in proper plumbing installations. 17-2122 Page 3 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa BlowerFigure 2 Manhole C5-177 - Large III Y P • � ..•,.. , sINVERSION4 17-2122 Page 4 of 18 Grandview Odor Control Study—Smoke Testing December of •. • Figure 3 Manhole C5-21 - Small Blower 7. maw A* - - Results Table 1 documents the instances of smoke emanating in the vicinity of the test location and notes the associated figure for each observation. A map is shown in Figure 4 which shows the locations of the instances of smoke. As anticipated, smoke was observed discharging from building roof vents and is further described in Table 1 along with other observations. 17-2122 Page 5 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho ,\B0I_Projects\17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Ah Eval Results`,Task Force",Smoke Test\Memc\TM-Fall PX_X ST LOCl_11.23.2020-doc, Table 1 Results DescriptionObservation Rgure Location Hamilton Manufacturing Inc. 1 5 (HMI) Smoke observed emanating from sewer vent 2 6 HMI Eastern Restroom Smoke observed emanating from under the Facility inside first toilet stall Magic Valley Recycling 3 7 Northwestern Building Drain Smoke observed emanating from sewer vent Vent 4 8 Magic Valley Recycling Smoke observed emanating from roof of Northwestern Building Office indoor office 5 9 HMI Storm drain at truck Smoke observed emanating from Storm drain scale at the truck scale 6 10 HMI Storm drain Smoke observed emanating from storm drain in the center of HMI 7 11 HMI Southern Building Smoke was not observed at the sewer vents of the HMI Southern Building 8 12 HMI Southern Building Sink Smoke was observed emanating from the Sink within the HMI Southern Building HMI Southern Building Smoke was observed emanating from the 9 13 Shower shower within the Magic Valley Recycling Southern Building Smoke was observed emanating from the Magic Valley Recycling ground near the second garage going east, at 10 14 Northwestern Building a blue truck. Upon further investigation, there Garage 2 loading dock may be a drain at this location, buried in silt, debris and vegetation. 1. Observation locations are shown on Figure 4. 17-2122 Page 6 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa 0 0 I C5-21 t5-177 3 e #�o A t: o a e • South Park Avenue West Legend Blower Test Manholes r� • Grandview Sewer Manholes j Grandview Sewer Trunkline • Sewer Manhole Observation Numbers are described in Table 1 Results 0 75 Feet Gravity Sewer -i—tar Geogr ph- U ES AIF us D-, 7SDA USGS.A—GRID IGN Grandview Odor Control Study Figure 4 _I'` Tw7N, MIS m��rraysm,7h Smoke Testing Location Results �+�i� Fi use 5 0b,),ery jtiu)n 1_ t' �+S'!'TJ'... " _�..�R _ --'_—•�-_ Illy . .i .. . 17-2122 Page 8 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa 17-2122 Page 9 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa Figure 7 Observation 3 17-2122 Page 10 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa Figure 8 Observation 4 i t 17-2122 Page 11 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa Figure 9 Observation 5 k\ 4 ice` � y 3 , 4 r.• �ti Y`fw• � 17-2122 Page 12 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa } �^w G 17-2122 Page 13 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa Figure 11 Observation 7 17-2122 Page 14 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa Figure 12 Observation 8 r 17-2122 Page 15 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho I';B01_Projects\17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Al;Eva!Results\Task.Force`l,Smoke Test',;Memo\TN9-Fall PX_X 5T L0C1_11.23.20Z0 doa. Figure 13 Observation 9 i 17-2122 Page 16 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho I';B01_Projects\17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eva!Results\Task.Force`l,Smoke Test',;Memo\TN9-Fall PX_X 5T L0C1_11.23.20Z0 doa. p TN sty i �Z. 1.; .•' •� _ ��*. �..`. Conclusion Smoke testing provided information on the integrity of the collection system in the main trunkline as well as sewer services and buildings connected to the sewer.The lack of smoke emanating from the ground at the alignment of the sewer pipes indicates the integrity of Trunkline is intact. The results of the test show that at least three storm drains are connected into the City's sewer system and show the existence of leaking plumbing within three buildings adjacent to the Trunkline. During the testing, it was mentioned by a staff member of the facilities that the location next to the truck scale has some of the worst sewer odors. This would likely be due to the cross- connected storm drain in this location. On non-windy days, these odors are likely to be suspended near this storm drain.The door to Hamilton Manufacturing, Inc. office building is directly adjacent to this storm drain, which can potentially be a source of odors migrating into the office. According to City Code of Twin Falls Chapter 7 Sewer Use Part 7-7-2-1.13.11, stormwater is prohibited from being discharged to the City's sanitary sewer collection system. Reports of sewer odors within the Northwest building are likely due to faulty plumbing above the office building allowing odors to 17-2122 Page 17 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa leak out of the sewer vent.The smoke observed in the southern-most building at the Magic Valley Recycling facility, is likely caused by faulty plumbing and to blame for the sewer odors reported in this building. Recommendations Recommendations include owners of buildings fixing faulty plumbing and disconnecting the storm drains from the sanitary sewer system. 17-2122 Page 18 of 18 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Test\Memo\TM-Fall PX.X ST LOCl_11.23.2020-doa murrzysmi7h` APPENDIX 1 CITY OF TMN FALLS OA`� Q�OQ SFRv1NG P.O.Box 1907 203 Main Ave East Twin Falls,Idaho 83303-1907 Fax: (208)736-2293 ENGINEERING 208-735-7248 October 1, 2020 Re: CITY OF TWIN FALLS SANITARY SEWER SMOKE TESTING Dear Residents and Property Owners, The City of Twin Falls in conjunction with their consultant, Murrysmith will be performing a smoke test in the sanitary sewer within the next few weeks. This testing will occur in the following areas (see attached map). Personnel associated with this study will have proper identification and vehicles will be clearly marked and recognizable. The objective of this test is to locate leaks,breaks, and defects in the sewer system.The smoke can also help identify areas of excess water inflow and infiltration. The results of the smoke testing will be used to identify sewer service areas that maybe experiencing issues in need of improvement. The smoke used for smoke testing is non-toxic,non-hazardous, and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter buildings, but if it does, it will have a distinct odor and should only last a few minutes with proper ventilation. If you do discover smoke in your structure,please open windows, and doors to allow smoke to leave. The Twin Falls Fire Department, Twin Falls Police Department, and Twin Falls Dispatch Office have been made aware of the smoke testing project areas and schedule. Additional information is available on the City of Twin Falls webpage: https://www.tfid.org/770/Sinoke-Testijig. We appreciate your patience and understanding and will make every effort to minimize the inconvenience or disruptions this project may have on you. If you have any further questions or concerns,please call 208-735-7248 and ask for me. Respectfully, J__1 1'3�� Jason Brown City of Twin Falls Environmental Engineer i STUDY AREA jol io Z lilt 6.04 . � p Google Earth � cn - ' '� � � ry = N• e%RA/'11/r IP1r\ITI1'In AT1r%L1 JIviuma IVCIV I Irll*iAll IVIV TESTING IN PROGRESS Please be informed that the City of Twin Falls will be testing sewer lines in this area by using Smoke Identification on: The smoke should not enter the premises unless a leak is present. The presence of smoke in your household should be reported to testing personnel by calling 208-735-7248. Smoke used for Smoke Identification is non- toxic, non-hazardous, and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter your building, but if it does, it will have a distinct odor that willl dissipate within a few minutes with proper ventilation. Persons with heart and respiratory ailments should leave the house during the test. House pets will react in a manner similar to a prudent person and leave the smokey area. If an exit is not available, be sure pets are provided with proper ventilation. To minimize the chance of smoke entering your home, or business, please pour water into all drains including floor drains prior to the test. Twnv�.is �1 'ftRVMB Latest News Tools Posted on: October 6, 2020 RSS City to Conduct Sewer Smoke Test in October; Test Will Identify Notify Me Leaks or Defects View Archived The City of Twin Falls in conjunction with Categories their consultant. Murrysmith will be - • All Categories performing a smoke test in the sanitary Latest News sewer within the next few weeks. This • Public Safety News testing will occur in the areas shown in the maps below. Personnel associated with this study will have proper identification and vehicles will be clearly marked and recognizable. The objective of this test is to locate leaks, breaks, and defects in the sewer system. The smoke can also help identify areas of excess water inflow and infiltration. The results of the smoke testing will be used to identify sewer service areas that maybe experiencing issues in need of improvement. The smoke used for smoke testing is non-toxic, non-hazardous. and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter buildings, but if it does, it will have a distinct odor and should only last a few minutes with proper ventilation. If you do discover smoke in your structure, please open windows, and doors to allow smoke to leave. The Twin Falls Fire Department. Twin Falls Police Department, and Twin Falls Dispatch Office have been made aware of the smoke testing project areas and schedule. Additional information is available on the City of Twin Falls webpage: https://www.tfid.org/770/Smoke-Testing We appreciate the public's patience and understanding and will make every effort to minimize the inconvenience or disruptions this project may have. Questions or concerns should be directed to Jason Brown, Environmental Engineer. at jbrown@tfid.org or 208-735-7248. October 2020 Testing Areas �� sruove�n 1� , Smoke Testing FAQ What exactly is a Smoke Test? A high capacity blower technique is used to test each sewer line with smoke. Smoke blowers are placed on manholes and smoke is blown through the sewer system. Any location where smoke is identified during the test, except plumbing vent stacks. is a potential break or Inflow/Infiltration source for excess water to enter the sewer system. These locations will be documented via pictures and sketches. What is the benefit to the City for performing a Smoke Test? Smoke testing is one technique utilized to identify sections of sewers that may exhibit inflow during heavy rainfall. Smoke testing is best used to detect inflow sources such as roof downspouts, driveway, yard and area drains. foundation drains, faulty connections, and storm water drainage system cross connections. It can also detect structural damages and leaking joints in sewer pipes. How will residents know when Smoke Testing will be performed in their neighborhoods? Prior to beginning the smoke testing. the City of Twin Falls will give notices to the community through its Public Service Announcement PSA system. Is the smoke that is used hazardous? The smoke that comes out of the vent stacks on houses or holes in the ground is non-toxic. harmless. It does not create a fire hazard. Twin Falls Police and Fire Departments will be made aware of the test areas and schedule. Will the smoke enter my home? The smoke will not enter a home if the plumbing is in good condition and if drain traps contain some water. Outside, it is normal for smoke to be seen coming from roof vents, building foundations. manhole covers and yard cleanouts. Smoke coming from the vents on the roofs of homes indicates to the work crew that smoke has filled all sewers. Smoke will enter your home if the vents connected to your buildings sewer pipe are inadequate, defective or improperly installed, if the traps under sinks. tubs, basins, showers and other drains are dry, defective, improperly installed or missing. or if the pipes, connections and seals of the wastewater drain system in and under your building are damaged. defective, has plugs missing, or are improperly installed. Does the resident need to be home when the Smoke Testing is performed? Homeowners do not need to be home and at no time will field crews need to enter the residence. Field inspectors will be documenting the testing, taking photos. and measuring distances so that the defects may be found later and repaired. You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) Can the resident stay inside while the testing is performed? Homeowners may stay inside during the testing. However. since any smoke may create minor irritations for some people with respiratory difficulties, those who have asthma, emphysema or other breathing problems are advised to avoid direct contact with the substance. What if the smoke does enter my house? If you see or smell the smoke inside your home. this could indicate that gases and odors from the sewer system also are entering. Notify the work crew immediately. Although we cannot correct any problems on private property, we can help identify the source so that you know what action to take. Will the smoke set off my smoke alarm? The smoke will not set off a smoke alarm nor is it a fire hazard. Twin Falls Fire Department will be notified in advance so they will know the difference between the testing and a true emergency. How are City crews recognizable in the field? Personnel carry identification badges. Crew members operate from vehicles with proper signage for ease of recognition. What happens after the smoke testing has been completed? The City of Twin Falls will notify residents who need to make corrections with a letter explaining the nature of defect found, ways to correct it. and a list of licensed sewer contractors who can make corrections. if need be. Again. most corrections can be easy fixes, such as disconnecting a downspout from the ground and letting the water flow above ground away from the home. What happens if the testing locates a leak or a bad connection to public lines? The work crew will document the information, which will be used by the Public Utilities Department to determine repair priorities and programs. �--� - -. :,,:�.;, -��. -_ - - -- • - -rat..-= rr 1 You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) Quick Links Helpful Links Frequently Asked Agendas, Minutes & Videos City Code Questions How do I get utilities set Bids/Requests for Proposals Maps .ob Openings Permits, Applications Where do I access the City & Fees budget? How do I register for recreation programs? You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) murrzysmi7h` APPENDIX 2 I c L w V v � d y w F i i W LLIN L F > V A O71 O V Q, � W O Nz 7 H L d O > > O O O L O F L T . 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R' SDS AND TEST DATA EXPLANATION Enclosed with this cover letter is a copy of our Safety Data Sheet (SDS - Formerly MSDS) for the liquid form of LiquiSmoke. and a summary of the Maxim Technologies and Wisconsin Occupational Health Laboratory reports on the smoke generated by Hurco's LiquiSmoke. Please note that only people who are using the `'raw" LiquiSmoke (the liquid form) will be concerned with the SIDS sheet. People who are exposed to the "smoke" LiquiSmoke only need to be concerned with the Maxim Technologies and WOHL reports. What is important to note on the SIDS sheet is Section 11 - Toxicological Information - it is not a potential carcinogen. The "raw" LiquiSmoke does not require any hazardous transportation documentation. Since there is not an SIDS for products in smoke form, we hired a private.. nationally recognized laboratory, Maxim Technologies, Inc. of Sioux Falls. South Dakota, to sample the smoke generated by LiquiSmoke. The samples were sent to the Wisconsin Occupational Health Laboratory where a GC Solvent Scan was performed. Of the 107 items listed in a GC Solvent Scan, only .01 parts per million (PPM) petroleum distillates was found. The OSHA Permissible Exposure Limit (PEL) is 500 ppm. Carbon Monoxide and Carbon Dioxide levels all tested within the OSHA PEL. This information is important to persons being exposed to the "smoke". Even though these test don't identify any harmful quantities of toxic compounds, you will need to warn your customers of dangerous sewer gases that may be traveling with the smoke. They should always be warned to evacuate the premise when smoke is detected. Finally, we had Maxim Technologies test the smoke generated by our LiquiSmoke for staining and residue. The tests showed that there was no staining or residue caused by LiquiSmoke. Your customers can rest assured that LiquiSmoke will not ruin their furniture or drapery. More information is included in the following document. "Scientific Evaluation of LiquiSmoke". If you have any questions or concerns about Hurco's LiquiSmoke, please contact me at 1-800-888-1436. Sincerely. ki�Cua Beckie Hurley Vice President DEMONSTRATIONS, VIDEOS • 010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFO01HURCOTECH.COM LIQUISMOKE MAXIM WOHL TEST RESULT TECHNOLOGIES ItFZ CM 4::3 SUMMARY TECHNOLOGIES , INC . ''' hbh�� Scientific Evaluation of LiquiSmoke TIJ A Summary of the Scientific Evaluation Reports Produced by Maxim Technologies of Sioux Falls, South Dakota During testing conducted by Maxim Technologies, the following facts concerning the smoke generated by LiquiSmoke were determined, under the guidelines set by The National Institute of Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). During the tests, Maxim Technologies collected a sample of the smoke generated by LiquiSmoke in a charcoal tube. The sample was sent to the Wisconsin Occupational Health Laboratory. A GC Solvent Scan was conducted to determine if the smoke generated by LiquiSmoke formed any hazardous compounds or conditions. The GC Solvent Scan searched for 107 different hazardous organic compounds. Of the 107 items listed, only .01 parts per million (ppm) petroleum distillates was found. The OSHA permissible Exposure Limit is 500 ppm. Further testing by Maxim Technologies found that the ambient carbon monoxide levels were found to be zero. NIOSH regulations have determined that the "8 hour time weighted average" (TWA) for carbon monoxide to be 35 ppm. During the duration of the test, measurable TWA levels of LiquiSmoke ranged from 4.6 to 7.8 ppm — within the OSHA Permissible Exposure Limit (PEL) set by OSHA. Maxim Technologies also tested for carbon dioxide levels. Ambient levels were found to be at 330 ppm. The level of carbon dioxide during the entire LiquiSmoke test was determined to be 500 ppm. The OSHA Permissible Exposure Limit (PEL) is 5,000 IDIOM. In addition, testing by Maxim Technologies was also performed to determine if usage of the product left any staining or odor. Residual staining and odor tests were conducted in a closed facility filled with LiquiSmoke. Time interval testing of filter paper samples exposed to LiquiSmoke were examined under a microscope at 40X magnification. In all cases, no visible staining was present, along with no odor on any of the filter papers exposed to the smoke. This summary is based on complete reports from Maxim Technologies of Sioux Falls, South Dakota. Copies of these tests, as well as the findings of the Wisconsin Occupational Health Laboratory, are available from Hurco Technologies, Inc. DEMONSTRATIONS, VIDEOS It MORE010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFOWHURCOTECH.COM LIQUISMOKE FOUND IN LIQUISMOKE • HL - COMPOUNDS NOTHVQCO TECH NO LOG I ES INC . "' Wisconsin Occupational Health Laboratory conducted an GC Solvent Scan looking for volatile organic compounds in Hurco's LiquiSmoke NONE OF THE COMPOUNDS LISTED BELOW WERE DETECTED IN HURCO'S LIQUISMOKE Acetone Dioxane (Diethylene Dioxide) Methyl Acrylate Allyl Alcohol Dioxolane - 1,3 Methyl Chloroform Amyl Acetate (n) Epichlorohydrin Methyl Isoamyl Ketone Amyl Alcohol Epoxybutane (1,2) Methyl Methacrylate Benzaldehyde Ethyl Alcohol Methyl Styrene Benzene Ethoxyethyl Acetate (2) Naphta (Coal Tar) Butatone (2) Ethyl Acetate Nonane Butyl Acetate (n) Ethyl Acrylate Octamethylcyclotetrasiloxane Butyl Acrylate Ethyl Benzene Octanol Butyl Alcohol (n) Ethyl Butyl Ketone P-Dichlorobenzene Butyl Alcohol (Sec) Ethyl Butyrate Pentane Butyl Alcohol (Tert) Ethyl Ether Pentanone (2) Butyl Glycidyl Ether Ethyl Methacrylate Perch lorethylene Butyl Methacrylate Ethyl Toluene Petroleum Distillate (Napththa) Carbon Tetrachloride Heptanone-2 (MBK) Pinene-Alpha Chlorobenzene Hexane (n) Pinene-Beta Chloroform Hexone (MIBK) Propanol Chloroprene Hexyl Acetate Propyl Acetate (n) Chlorostyrene Isoamyl Acetate Styrene Chlorotoluene (o) Isoamyl Alcohol Tetrahydrofuran Cumene Isobutyl Alcohol Toluene Cyclohexanol Isobutyl Isobutrate Trichloro-Benzene (1,2,4) Cyclohexanone lospropyl Acetate Trichloro-Ethane(1,1,2) Decamenthyl Cyclopentasiloxane Isopropyl Alcohol Trichloroethylene Diochlorethane (1,1) Isopropyl Ether Vinyl Acetate Diochlorethane (1,2) Mesityl Oxide Xylene (o, m & p) Diisobutyl Ketone Methyl Acetate DEMONSTRATIONS, VIDEOS • ' 010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFOwHURCOTECH.COM murraysmi h >w Technical Memorandum Grandview Odor Control Study •- Phase 2 Smoke Testing City of Twin Falls, Idaho %\0 EAs �O yv Date: December 14, 2020 a Project: City of Twin Falls: Grandview Odor Control Study Phase 2 OF To: City of Twin Falls, Idaho �r A. Cuidi' �.1 a•Z J From: Murraysmith Introductiol This memorandum documents the events of the smoke testing on the Grandview Trunkline (Trunkline) on October 7, 2020. The purpose of the smoke testing was to provide a localized condition assessment for frequent odor complaint location along the Trunkline. Testing inn The location determined for the testing was an area of the trunkline at Canyon Rim Road before the Trunkline drops down into the Snake River canyon and enters the WWTP. The manholes used for the test were as follows: • B1-4; and • B1-29. Figures 1 shows the testing location. 17-2122 Page 1 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho 34 �a • -d � t A 9k o Z D ; e eta oad - • a r ; i Legend • Grandview Sewer Manholes t, Grandview Sewer Trunkline _ 0 750 Feet Gravity Sewer rth— Source Esr Maxar GooEye:E^mvTSt Geograp�,cs GNES Airtius DS-USDA.USGS,AeroGRID-15'. and the GIS User Community 1'VGUI�FNJ./ Grandview Odor Control Study Figure 1 murraysmi Smoke Testing Test Location-+*�� Smoke Test The smoke testing took place on October 7, 2020. The smoke testing was provided by Sweet's Septic Tank & Backhoe Service Inc. (Sweet's). Procedure Notification Before the smoke testing took place, the City provided letters and "doorhangers" to customers who may experience instances of smoke during the testing. The letter and doorhanger are attached in Appendix 1. Additionally, notification was sent to the City's emergency responders including the Twin Falls Fire Department, Twin Falls Police Department, and Twin Falls Dispatch Office, informing them that smoke testing would take place and that they may receive calls reporting smoke around the two testing locations. The City also provided a notice on the City website, including a Frequently Asked Questions (FAQ), informing the public of the smoke testing. The FAQ is also attached in Appendix 1. Equipment Sweet's provided smoke testing via two manhole-placed blowers. The larger blower was a Hurco Super Power Smoker which has a 5.5-HP engine and approximate capacity of 8,760 cfm. The smaller blower is a Hurco Super Smoker 2 with a 2.5-HP engine and approximate capacity of 700 cfm. Figures 2 and 3 show the manholes and blowers that were utilized for the tests. The smoke was provided by a liquid smoke solution (LiquiSmoke by Hurco) that when introduced to blower exhaust, creates a non-toxic white smoke which is then blown into the sewer.The Safety Data Sheet (SDS) for the liquid solution and an independent analysis of the smoke byproduct is included in Appendix 2. Setup The two blowers were placed on manholes to force smoke to in the sewer collection system. Testing Each blower was activated, and smoke was applied to the sewer system. Smoke was emitted into the sewer system until positive occurrences of smoke were observed emanating from surfaces, structures and/or buildings. Smoke was continuously blown into the system until relevant instances of smoke could be documented. Each instance of smoke was noted, pictures were taken, and if required, further investigation was undertaken to locate the source of the individual smoke occurrence. Smoke emanating from roof vents above building rooflines is normal and anticipated to occur in proper plumbing installations. 17-2122 Page 3 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa Figure 2 Manhole B1-4 - Large Blower rr A • 17-2122 Page 4 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa Figure 3 Manhole B1-29 - Small Blower r. QR ff °°a •° ff O Results Table 1 documents the instances of smoke emanating in the vicinity of the test location and notes the associated figure for each observation. A map is shown in Figure 4 which shows the locations of the instances of smoke. As anticipated, smoke was observed discharging from building roof vents and is further described in Table 1 along with other observations. 17-2122 Page 5 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa T bk 1 r�c.-l.I.tS 7 , eII ar: ee Ir. r a et � e Smoke observed emanating from all sewer 1 5 465 Canyon Rim Road` roof vents. No instances of smoke noted inside residence. Smoke observed emanating from at least one sewer roof vent. Could not positively identify 2 6 491 Canyon Rim Road' if smoke was emanating from southern most sewer roof vents. No instances of smoke noted inside residence. Smoke observed emanating from sewer roof vents. Homeowner notified City of smoke 3 7 520 Canyon Rim Road' inside house. Smoke was observed in the crawl space of the house, indicating possible broken sewer drainpipe within the crawl space. Smoke observed emanating from all sewer roof vents except for kitchen vent. Homeowner notified City of smoke inside 4 8 548 Canyon Rim Road' house. Smoke was observed in the crawl space of the house.The smoke was more concentrated in the location of the kitchen within the crawl space. Note: 1. Observation locations are shown on Figure 4. 2. Photos not taken inside residence. 17-2122 Page 6 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa #3 #4 GOPr B1-5 Canyon Rim Road B1_47 0B1-4 o T ®1-29B1-3 0 #2 �z • 1 0� T) Y CU — -+ s Legend • Blower Test Manhole • Grandview Sewer Manholes Grandview Sewer Trunkline • Sewer Manhole *'k Observation Numbers are described in Table 1 Results o 75 Feet Gravity Sewer Source Esn Maxar GeoEyo Earthstar 6eographics CNESAirr—DS USDA USGS.Aerc(4RID IGP_ and the GIS User Community '�`W'IY FAI.IS Grandview Odor Control Study Figure 4 murraysm,7h -- Smoke Testing Location Results �` 17-2122 Page 8 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa Figure 6 Observation 2 17-2122 Page 9 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho I';B01_Projects\17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 SamplmgAl:Eva!ResultslTask.Force'l;Smoke Tee—:\Nlemo\TN9-Fall PX_X 5T L0C2_1214.2020-doa. , r _ I �> r 3.'i�' rl >'• jP''�3��:,�41i-.' -�,�,�•, 1�,,r � ' �1�" s' ,ti=��pia ` �4 y�4� a � _ Y �v t�f •t r �xsr � ti f �yy��i i� qdy + RV�,t vC �l��NS�p. d ,V� k X.,4 '�'rai t� ♦ veA' `�.�+��,� f, - YG+�, ;,�F s { rr }�f�,- �,,�5.'rY�B�yyrIn{fi3,l�4iy� •'I Y f tC� tu��tl �)}�n ,�' i�� rp �� ,_�Fih' {t u.,, Y.i + t ,l,�T r i 4h.•dt�EYf n y.19�1' R k i.�0 �Idpe _.C � +, . '0' � J��'t d F.r � �rx l: � �iT t� ,,.,i Rr' 3{, �, a n.S• �Pt:r R h:�y'N�;r ka,. t e,�`: Conclusion Smoke testing provided information on the integrity of the collection system in the main trunkline as well as sewer services and buildings connected to the sewer.The lack of smoke emanating from the ground at the alignment of the sewer pipes indicates the integrity of the Trunkline is intact. 17-2122 Page 11 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa Reports of odors in the testing area are likely due to faulty plumbing within private residences. Two of the four residences in the area had smoke observed in the crawlspace which is likely due to faulty plumbing in the crawl space of the house. Recommendations Recommendations include owners of buildings fixing faulty plumbing. 17-2122 Page 12 of 12 Grandview Odor Control Study—Smoke Testing December 2020 City of Twin Falls, Idaho t:\BOI_Projec&s 17\2122-Twin Falls Grandview Odor\Phase 2\Task 3 45 Sampling Alt Eval Results\Task Force\Smoke Tes.\Memo\TM-Fall PX.X ST LOC2_12.14.2020-doa murrzysmi7h` APPENDIX 1 CITY OF TMN FALLS OA`� Q�OQ SFRv1NG P.O.Box 1907 203 Main Ave East Twin Falls,Idaho 83303-1907 Fax: (208)736-2293 ENGINEERING 208-735-7248 October 1, 2020 Re: CITY OF TWIN FALLS SANITARY SEWER SMOKE TESTING Dear Residents and Property Owners, The City of Twin Falls in conjunction with their consultant, Murrysmith will be performing a smoke test in the sanitary sewer within the next few weeks. This testing will occur in the following areas (see attached map). Personnel associated with this study will have proper identification and vehicles will be clearly marked and recognizable. The objective of this test is to locate leaks,breaks, and defects in the sewer system.The smoke can also help identify areas of excess water inflow and infiltration. The results of the smoke testing will be used to identify sewer service areas that maybe experiencing issues in need of improvement. The smoke used for smoke testing is non-toxic,non-hazardous, and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter buildings, but if it does, it will have a distinct odor and should only last a few minutes with proper ventilation. If you do discover smoke in your structure,please open windows, and doors to allow smoke to leave. The Twin Falls Fire Department, Twin Falls Police Department, and Twin Falls Dispatch Office have been made aware of the smoke testing project areas and schedule. Additional information is available on the City of Twin Falls webpage: https://www.tfid.org/770/Sinoke-Testijig. We appreciate your patience and understanding and will make every effort to minimize the inconvenience or disruptions this project may have on you. If you have any further questions or concerns,please call 208-735-7248 and ask for me. Respectfully, J__1 1'3�� Jason Brown City of Twin Falls Environmental Engineer i STUDY AREA jol io Z lilt 6.04 . � p Google Earth � cn - ' '� � � ry = N• e%RA/'11/r IP1r\ITI1'In AT1r%L1 JIviuma IVCIV I Irll*iAll IVIV TESTING IN PROGRESS Please be informed that the City of Twin Falls will be testing sewer lines in this area by using Smoke Identification on: The smoke should not enter the premises unless a leak is present. The presence of smoke in your household should be reported to testing personnel by calling 208-735-7248. Smoke used for Smoke Identification is non- toxic, non-hazardous, and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter your building, but if it does, it will have a distinct odor that willl dissipate within a few minutes with proper ventilation. Persons with heart and respiratory ailments should leave the house during the test. House pets will react in a manner similar to a prudent person and leave the smokey area. If an exit is not available, be sure pets are provided with proper ventilation. To minimize the chance of smoke entering your home, or business, please pour water into all drains including floor drains prior to the test. Twnv�.is �1 'ftRVMB Latest News Tools Posted on: October 6, 2020 RSS City to Conduct Sewer Smoke Test in October; Test Will Identify Notify Me Leaks or Defects View Archived The City of Twin Falls in conjunction with Categories their consultant. Murrysmith will be - • All Categories performing a smoke test in the sanitary Latest News sewer within the next few weeks. This • Public Safety News testing will occur in the areas shown in the maps below. Personnel associated with this study will have proper identification and vehicles will be clearly marked and recognizable. The objective of this test is to locate leaks, breaks, and defects in the sewer system. The smoke can also help identify areas of excess water inflow and infiltration. The results of the smoke testing will be used to identify sewer service areas that maybe experiencing issues in need of improvement. The smoke used for smoke testing is non-toxic, non-hazardous. and manufactured specifically for this purpose. It leaves no residual or stains and has no effect on plants or animals. The smoke should not enter buildings, but if it does, it will have a distinct odor and should only last a few minutes with proper ventilation. If you do discover smoke in your structure, please open windows, and doors to allow smoke to leave. The Twin Falls Fire Department. Twin Falls Police Department, and Twin Falls Dispatch Office have been made aware of the smoke testing project areas and schedule. Additional information is available on the City of Twin Falls webpage: https://www.tfid.org/770/Smoke-Testing We appreciate the public's patience and understanding and will make every effort to minimize the inconvenience or disruptions this project may have. Questions or concerns should be directed to Jason Brown, Environmental Engineer. at jbrown@tfid.org or 208-735-7248. October 2020 Testing Areas �� sruove�n 1� , Smoke Testing FAQ What exactly is a Smoke Test? A high capacity blower technique is used to test each sewer line with smoke. Smoke blowers are placed on manholes and smoke is blown through the sewer system. Any location where smoke is identified during the test, except plumbing vent stacks. is a potential break or Inflow/Infiltration source for excess water to enter the sewer system. These locations will be documented via pictures and sketches. What is the benefit to the City for performing a Smoke Test? Smoke testing is one technique utilized to identify sections of sewers that may exhibit inflow during heavy rainfall. Smoke testing is best used to detect inflow sources such as roof downspouts, driveway, yard and area drains. foundation drains, faulty connections, and storm water drainage system cross connections. It can also detect structural damages and leaking joints in sewer pipes. How will residents know when Smoke Testing will be performed in their neighborhoods? Prior to beginning the smoke testing. the City of Twin Falls will give notices to the community through its Public Service Announcement PSA system. Is the smoke that is used hazardous? The smoke that comes out of the vent stacks on houses or holes in the ground is non-toxic. harmless. It does not create a fire hazard. Twin Falls Police and Fire Departments will be made aware of the test areas and schedule. Will the smoke enter my home? The smoke will not enter a home if the plumbing is in good condition and if drain traps contain some water. Outside, it is normal for smoke to be seen coming from roof vents, building foundations. manhole covers and yard cleanouts. Smoke coming from the vents on the roofs of homes indicates to the work crew that smoke has filled all sewers. Smoke will enter your home if the vents connected to your buildings sewer pipe are inadequate, defective or improperly installed, if the traps under sinks. tubs, basins, showers and other drains are dry, defective, improperly installed or missing. or if the pipes, connections and seals of the wastewater drain system in and under your building are damaged. defective, has plugs missing, or are improperly installed. Does the resident need to be home when the Smoke Testing is performed? Homeowners do not need to be home and at no time will field crews need to enter the residence. Field inspectors will be documenting the testing, taking photos. and measuring distances so that the defects may be found later and repaired. You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) Can the resident stay inside while the testing is performed? Homeowners may stay inside during the testing. However. since any smoke may create minor irritations for some people with respiratory difficulties, those who have asthma, emphysema or other breathing problems are advised to avoid direct contact with the substance. What if the smoke does enter my house? If you see or smell the smoke inside your home. this could indicate that gases and odors from the sewer system also are entering. Notify the work crew immediately. Although we cannot correct any problems on private property, we can help identify the source so that you know what action to take. Will the smoke set off my smoke alarm? The smoke will not set off a smoke alarm nor is it a fire hazard. Twin Falls Fire Department will be notified in advance so they will know the difference between the testing and a true emergency. How are City crews recognizable in the field? Personnel carry identification badges. Crew members operate from vehicles with proper signage for ease of recognition. What happens after the smoke testing has been completed? The City of Twin Falls will notify residents who need to make corrections with a letter explaining the nature of defect found, ways to correct it. and a list of licensed sewer contractors who can make corrections. if need be. Again. most corrections can be easy fixes, such as disconnecting a downspout from the ground and letting the water flow above ground away from the home. What happens if the testing locates a leak or a bad connection to public lines? The work crew will document the information, which will be used by the Public Utilities Department to determine repair priorities and programs. �--� - -. :,,:�.;, -��. -_ - - -- • - -rat..-= rr 1 You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) Quick Links Helpful Links Frequently Asked Agendas, Minutes & Videos City Code Questions How do I get utilities set Bids/Requests for Proposals Maps .ob Openings Permits, Applications Where do I access the City & Fees budget? How do I register for recreation programs? You created this PDF from an application that is not licensed to print to novaPDF printer(http://www.novapdf.com) murrzysmi7h` APPENDIX 2 I c L w V v � d y w F i i W LLIN L F > V A O71 O V Q, � W O Nz 7 H L d O > > O O O L O F L T . 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R' SDS AND TEST DATA EXPLANATION Enclosed with this cover letter is a copy of our Safety Data Sheet (SDS - Formerly MSDS) for the liquid form of LiquiSmoke. and a summary of the Maxim Technologies and Wisconsin Occupational Health Laboratory reports on the smoke generated by Hurco's LiquiSmoke. Please note that only people who are using the `'raw" LiquiSmoke (the liquid form) will be concerned with the SIDS sheet. People who are exposed to the "smoke" LiquiSmoke only need to be concerned with the Maxim Technologies and WOHL reports. What is important to note on the SIDS sheet is Section 11 - Toxicological Information - it is not a potential carcinogen. The "raw" LiquiSmoke does not require any hazardous transportation documentation. Since there is not an SIDS for products in smoke form, we hired a private.. nationally recognized laboratory, Maxim Technologies, Inc. of Sioux Falls. South Dakota, to sample the smoke generated by LiquiSmoke. The samples were sent to the Wisconsin Occupational Health Laboratory where a GC Solvent Scan was performed. Of the 107 items listed in a GC Solvent Scan, only .01 parts per million (PPM) petroleum distillates was found. The OSHA Permissible Exposure Limit (PEL) is 500 ppm. Carbon Monoxide and Carbon Dioxide levels all tested within the OSHA PEL. This information is important to persons being exposed to the "smoke". Even though these test don't identify any harmful quantities of toxic compounds, you will need to warn your customers of dangerous sewer gases that may be traveling with the smoke. They should always be warned to evacuate the premise when smoke is detected. Finally, we had Maxim Technologies test the smoke generated by our LiquiSmoke for staining and residue. The tests showed that there was no staining or residue caused by LiquiSmoke. Your customers can rest assured that LiquiSmoke will not ruin their furniture or drapery. More information is included in the following document. "Scientific Evaluation of LiquiSmoke". If you have any questions or concerns about Hurco's LiquiSmoke, please contact me at 1-800-888-1436. Sincerely. ki�Cua Beckie Hurley Vice President DEMONSTRATIONS, VIDEOS • 010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFO01HURCOTECH.COM LIQUISMOKE MAXIM WOHL TEST RESULT TECHNOLOGIES ItFZ CM 4::3 SUMMARY TECHNOLOGIES , INC . ''' hbh�� Scientific Evaluation of LiquiSmoke TIJ A Summary of the Scientific Evaluation Reports Produced by Maxim Technologies of Sioux Falls, South Dakota During testing conducted by Maxim Technologies, the following facts concerning the smoke generated by LiquiSmoke were determined, under the guidelines set by The National Institute of Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). During the tests, Maxim Technologies collected a sample of the smoke generated by LiquiSmoke in a charcoal tube. The sample was sent to the Wisconsin Occupational Health Laboratory. A GC Solvent Scan was conducted to determine if the smoke generated by LiquiSmoke formed any hazardous compounds or conditions. The GC Solvent Scan searched for 107 different hazardous organic compounds. Of the 107 items listed, only .01 parts per million (ppm) petroleum distillates was found. The OSHA permissible Exposure Limit is 500 ppm. Further testing by Maxim Technologies found that the ambient carbon monoxide levels were found to be zero. NIOSH regulations have determined that the "8 hour time weighted average" (TWA) for carbon monoxide to be 35 ppm. During the duration of the test, measurable TWA levels of LiquiSmoke ranged from 4.6 to 7.8 ppm — within the OSHA Permissible Exposure Limit (PEL) set by OSHA. Maxim Technologies also tested for carbon dioxide levels. Ambient levels were found to be at 330 ppm. The level of carbon dioxide during the entire LiquiSmoke test was determined to be 500 ppm. The OSHA Permissible Exposure Limit (PEL) is 5,000 IDIOM. In addition, testing by Maxim Technologies was also performed to determine if usage of the product left any staining or odor. Residual staining and odor tests were conducted in a closed facility filled with LiquiSmoke. Time interval testing of filter paper samples exposed to LiquiSmoke were examined under a microscope at 40X magnification. In all cases, no visible staining was present, along with no odor on any of the filter papers exposed to the smoke. This summary is based on complete reports from Maxim Technologies of Sioux Falls, South Dakota. Copies of these tests, as well as the findings of the Wisconsin Occupational Health Laboratory, are available from Hurco Technologies, Inc. DEMONSTRATIONS, VIDEOS It MORE010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFOWHURCOTECH.COM LIQUISMOKE FOUND IN LIQUISMOKE • HL - COMPOUNDS NOTHVQCO TECH NO LOG I ES INC . "' Wisconsin Occupational Health Laboratory conducted an GC Solvent Scan looking for volatile organic compounds in Hurco's LiquiSmoke NONE OF THE COMPOUNDS LISTED BELOW WERE DETECTED IN HURCO'S LIQUISMOKE Acetone Dioxane (Diethylene Dioxide) Methyl Acrylate Allyl Alcohol Dioxolane - 1,3 Methyl Chloroform Amyl Acetate (n) Epichlorohydrin Methyl Isoamyl Ketone Amyl Alcohol Epoxybutane (1,2) Methyl Methacrylate Benzaldehyde Ethyl Alcohol Methyl Styrene Benzene Ethoxyethyl Acetate (2) Naphta (Coal Tar) Butatone (2) Ethyl Acetate Nonane Butyl Acetate (n) Ethyl Acrylate Octamethylcyclotetrasiloxane Butyl Acrylate Ethyl Benzene Octanol Butyl Alcohol (n) Ethyl Butyl Ketone P-Dichlorobenzene Butyl Alcohol (Sec) Ethyl Butyrate Pentane Butyl Alcohol (Tert) Ethyl Ether Pentanone (2) Butyl Glycidyl Ether Ethyl Methacrylate Perch lorethylene Butyl Methacrylate Ethyl Toluene Petroleum Distillate (Napththa) Carbon Tetrachloride Heptanone-2 (MBK) Pinene-Alpha Chlorobenzene Hexane (n) Pinene-Beta Chloroform Hexone (MIBK) Propanol Chloroprene Hexyl Acetate Propyl Acetate (n) Chlorostyrene Isoamyl Acetate Styrene Chlorotoluene (o) Isoamyl Alcohol Tetrahydrofuran Cumene Isobutyl Alcohol Toluene Cyclohexanol Isobutyl Isobutrate Trichloro-Benzene (1,2,4) Cyclohexanone lospropyl Acetate Trichloro-Ethane(1,1,2) Decamenthyl Cyclopentasiloxane Isopropyl Alcohol Trichloroethylene Diochlorethane (1,1) Isopropyl Ether Vinyl Acetate Diochlorethane (1,2) Mesityl Oxide Xylene (o, m & p) Diisobutyl Ketone Methyl Acetate DEMONSTRATIONS, VIDEOS • ' 010117 • 409 ENTERPRISE STREET - HARRISBURG, SD 57032 - 800-888-1436 - INFOwHURCOTECH.COM