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TECHNICAL MEMORANDUM TO: Mr. Garner Reynolds, City of Turlock FROM: Jeffrey Lodge, P.E., Wood Rodgers, Inc. Eddie Gosse, P.E., Wood Rodgers, Inc. DATE: October 23, 2018 Revised January 15, 2019 SUBJECT: City of Turlock – Arsenic & Trichloropropane Well Treatment Technical

Memorandum FINAL INTRODUCTION The purpose of this Technical Memorandum (TM) is to summarize the basis for the City of Turlock’s (City) approach to Wellhead Treatment of Arsenic and/or 1,2,3 Trichloropropane (TCP) at Wells 4, 19, 29, 30, 35, 36, and 38. The levels of Arsenic and TCP in the groundwater obtained from the wells has been increasing in the last few years. The units of measurement for both Arsenic and TCP are in parts per billion (ppb) one ppb is equivalent to 1 microgram per liter. The levels for Arsenic and TCP varies as shown in Table 1.

Table 1 – Flowrates and Constituent Levels Well Number Flow Rate Issue

Well 4 1,038 gpm TCP (0.028 ppb)

Well 19 980 gpm TCP (0.066 ppb)

Well 29 1,240 gpm TCP (0.010 ppb)

Well 30 1,013 gpm TCP (0.006 ppb)

Well 35 1,655 gpm TCP (0.023 ppb)

Well 36 2,013 gpm Arsenic (9.1 ppb)

Well 38 2,793 gpm Arsenic (12 ppb)

This TM includes review of available constructible areas on each of the well sites, connection of required infrastructure for treatment, location of equipment on each of the sites, disposal of any bi-product from the treatment, changes in existing equipment at each site, capital cost for the treatment improvements, and operations and maintenance costs.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 2 of 21 BACKGROUND The City currently relies entirely on groundwater as its source of supply of municipal water to its consumer base through a network of 25 wells. The City has 18 active wells with four offline due to water quality issues and two designated on stand-by-status. Well 8, previously treated for Ethylene Dibromide (EDB) using Granular Activated Carbon (GAC), is currently being rehabilitated to provide treatment of TCP. These active wells pump groundwater directly into the City distribution system which delivers potable water to 18,500 service connections. The City currently does not have wells in their system that have wellhead treatment. The location of the wells are shown in Figure 1. As of 2015, the City of Turlock’s groundwater capability was 35,084 gpm. Based on individual well nameplate pumping capacity, the loss of Wells 4, 19, 29, 30, 35, 36 & 38 contribution to pump into the distribution system represents a 30.6% loss in available capacity. In 2008, those listed wells that are now impacted by TCP and arsenic accounted for 32% and 8% respectively of the overall wellfield production of 7.63 billion gallons. Since the year 2008 there has been a 14% reduction in water usage with the drought, implementation of water savings incentives and public outreach. However, from the data available in 2014 the City of Turlock will lose 20% of its wellfield production from those same wells if they are taken offline due to these water quality issues. This action will reduce flexibility, redundancy, reliability and increases pumping of the other wells in their system without the ability to allow those aquifers to rest and recover. Location and Physical Setting The City is located in Stanislaus County, south of Modesto and north of Merced, along the State Highway 99 corridor. Within the City limits, land use consists of residential, industrial, and general commercial. The City is situated in the San Joaquin Valley, which is separated into two hydrologic areas: the southern portion is referred as the Tulare Lake Hydrologic Region and the northern portion where the City is located is referred as the San Joaquin Valley Hydrologic Region. The San Joaquin Hydrologic Region covers an area of approximately 15,200 square miles and includes all of Calaveras, Tuolumne, Mariposa, Madera, San Joaquin, and Stanislaus counties (DWR, 2003). Major rivers exist both north and west of the City: the San Joaquin River is located approximately eight miles west and the Tuolumne River approximately six miles to the north. There are no major streams or rivers actually within the City limits. The Turlock Irrigation District (TID) operates and maintains several east-west orientated lined canals within the City, located parallel to Taylor Road in the north, Canal Road in the central portion of the City, and East Harding Road.

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PRELIMINARY

CITY WELL FIELD LOCATION MAPCITY OF TURLOCK

ARSENIC AND TRICHLOROPROPANETECHINCAL MEMORANDUM

TURLOCK, CALIFORNIAJANUARY 2019

NORTH

J:\Jobs\8604_Turlock\8604.00X_Treatment\GIS\Tasks\F01_Turlock_Well_Location_Map.mxd 1/10/2019 3:58:32 PM sspaeth FIGURE 1

Vicinity MapNot to Scale

Notes: Abandoned/Destroyed well locations are approximated tonearest intersection.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 3 of 21 Current Water Quality Regulations Arsenic Arsenic is a common element in the earth’s crust, natural groundwater, and even the human body. It is an odorless and tasteless semi-metal (metalloid) that is naturally present in aquifers throughout the U.S. and the world. On June 22, 2000, the U.S. Environmental Protection Agency (EPA) proposed lowering the maximum contaminant level (MCL) for arsenic from 50 down to 5 ppb (Federal Register, 2000). Their proposal followed the recommendation of the National Academy of Sciences report, which concluded that the current 50 ppb standard was not sufficiently protective of public health, and should be lowered as soon as possible (NAS, 1999). EPA estimated that the proposed 5 ppb standard would provide additional protection for 22.5 million Americans from cancer and other health problems. Because of anticipated objections from both environmentalists and water suppliers, MCLs of 3, 10 and 20 ppb also were being considered. The final MCL was announced at 10 ppb in late January of 2001 for compliance by 2006. Trichloropropane (TCP) TCP is a manmade chlorinated hydrocarbon with high chemical stability which was used as a cleaning and degreasing solvent, and also is associated with pesticide products. In California, studies have shown that TCP causes cancer in laboratory animals and is likely carcinogenic to humans as interpreted by the state. In 1992, TCP was added to the list of chemicals known to the state to cause cancer, pursuant to California's Safe Drinking Water and Toxic Enforcement Act (Proposition 65). In 1999, the State of California Water Resources Department of Public Health (now known as the Division of Drinking Water) established a 0.005-ppb drinking water notification level for TCP. This value is based on cancer risks derived from laboratory animal studies conducted by the USEPA. The timeline and decision making process since 1999 is shown below:

2001 - TCP added to Uncontaminated Contaminant Monitoring Rule (UCMR) 2004 – Public health goal (PHG) for TCP requested 2007 – California Office of Environmental Health Hazard Assessment (OEHHA) Draft

PHG of 0.0007 ppb technical support document released 2009 – OEHHA established a PHG of 0.0007 ppb for TCP July 2018 – State Water Resources Control Board Division of Drinking Water adopted a

new primary maximum contaminant level (MCL) of 0.005 ppb for TCP SYSTEM DESCRIPTION

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 4 of 21 The City of Turlock water system consists of 40 wells and miles of distribution piping to convey potable water to their service area. The 40-well wellfield consists of the following:

18 active wells 6 inactive wells 3 standby wells 13 abandoned/destroyed wells

TREATMENT The City of Turlock is considering wellhead treatment for Arsenic and TCP for seven of their source water wells. Arsenic levels in wells 36 & 38 are at or just above the MCL. Levels of TCP vary from just at the detection level (MCL) to 10 times the detection level and impact wells 4, 19, 29, 30 & 35. Each constituent has several types of treatment that have been approved and shown to be effective in reduction or removal, as described in the next section. Arsenic Treatment Arsenic removal alternatives from potable water sources with wellhead treatment include:

Oxidation/Filtration

Coagulation/Filtration with iron augmentation

Adsorption using granular ferric oxide media

The most effective types of treatment for arsenic are very much dependent on the form of arsenic that is in the water to be treated. Oxidation of arsenic to transform arsenic from As(III) to As(V) has been proven to improve the performance of the technologies for removal of this constituent. Several oxidants have been used as a pretreatment to achieve this including chlorine, potassium permanganate, aeration, peroxide, ozone, and photo-oxidation. When oxidation has been completed and arsenic has been converted to As(V), a very cost-effective method for removal consists of multi-media filtration. The oxidation/filtration process for removal of the arsenic will require addition of ferric chloride. After the oxidation phase, the arsenic in the form of As(V) then attaches to the iron hydroxide and is filtered out. The ferric chloride is naturally acidic and may require addition of caustic soda to raise the pH level of the water following filtration. The chemical process of coagulation and precipitation changes the state of the constituent so that it may be filtered out by the physical process. This process is termed coagulation/filtration (CF) in the water treatment industry. Common coagulants used for arsenic treatment are iron salts and aluminum sulfate (alum). Alum coagulation is generally less efficient than iron coagulation, so alum would only be appropriate for systems with low arsenic concentrations. Typical iron salts

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 5 of 21 used are ferric chloride and ferric sulfate. Following coagulation, a process such as multimedia filtration with automated backwashing is typically used to remove precipitated arsenic. Adsorptive media is another common technology for arsenic removal that can be used in place of or to augment CF. As with coagulants, most adsorptive media are iron-based; variations include titanium dioxide, zirconium, and other ion exchange resins. As with CF systems, a variety of equipment and materials suppliers are available. Reducing pH to the 5 to 7 range can enhance adsorptive media’s effectiveness. In adsorption, solutes (contaminants) concentrate at the surface of a sorbent, thereby reducing their concentration in the bulk liquid phase. The adsorption media is usually packed into a column. As contaminated water is passed through the column, contaminants are adsorbed. When adsorption sites become filled, the column must be regenerated, or disposed of and replaced with new media. Of the treatment methods described above, Oxidation/Filtration has been a proven successful and economical method for removal of Arsenic at multiple water treatment facilities of various water utility purveyors. For planning and layout purposes, Oxidation/Filtration is the preferred arsenic treatment alternative, see Wood Rodgers, Inc. authored Hydrogeologic & Water Quality Assessment Wellhead Arsenic Treatment Evaluation Technical Memorandum dated July 6, 2016. Refer to Figure 2 for an example of typical equipment arrangement for Arsenic removal treatment of approximately 1,500 gpm of groundwater. TCP Treatment TCP removal treatment is accomplished by several alternative methods including:

Biological Reverse osmosis Granular Activated Carbon (GAC) adsorption

Biological treatment for TCP removal from drinking water involves introduction of microorganisms into the product water as a method of treatment. Bacteria gain energy and reproduce by mediating the transfer of electrons from reduced compounds (i.e., compounds that readily donate electrons) to oxidized compounds (i.e., compounds that readily accept electrons). Once electrons are donated by a reduced compound, they travel across a cell’s mitochondrial membrane in a series of internal oxidation-reduction reactions. Ultimately the electrons are donated to the terminal electron-accepting compound. As compounds gain or lose electrons, they are converted to different, often innocuous, forms that are thermodynamically more stable than the original compounds. The fixed-bed, dual stage biological treatment method creates a robust environment for microbiological organisms to destroy contaminants or reduce elements to simple non-harmful forms. Developed specifically for drinking water applications, the fixed-bed treatment process

FIGURE 2 - ARSENIC TREATMENT

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 6 of 21 consistently addresses contaminants at low levels in either intermittent or fixed operation, and the dual-bed assimilates a complete packaged biotreatment plant with a dependability which is required for protecting public health. Reverse osmosis (RO) is a membrane separation process for removing a constituent from a solution. When a semi-permeable membrane separates a dilute solution from a concentrated solution, the constituent crosses from the dilute solution side to the concentrated side of the membrane in an attempt to equalize concentrations. The flow of solvent can be prevented by applying an opposing hydrostatic pressure to the concentrated solution. RO is one of the more expensive treatment processes available and creates a brine that must also be disposed of. The increase pressure and brine waste disposal costs, are costs that the City must take on for the lifetime of operations if this process method is implemented. Adsorption treatment using Granular Activated Carbon (GAC) is currently the most effective and economical method for wellhead or centralized treatment of TCP. GAC is commonly used to adsorb natural organic compounds, taste and odor compounds, and synthetic organic chemicals in drinking water treatment. Adsorption is both the physical and chemical process of accumulating a substance at the interface between liquid and solids phases. Activated carbon is an effective adsorbent because it is a highly porous material and provides a large surface area to which contaminants may adsorb.

GAC is made from organic materials with high carbon contents such as wood, lignite and coal. GAC typically has a diameter ranging between 1.2 to 1.6 mm and an apparent density ranging between 25 and 31 lb/ft3), depending on the material used and manufacturing process. The bed density is about 10 percent less than the apparent density and is used to determine the amount of GAC required to fill a given size filter. The uniformity coefficient of GAC is quite large, typically about 1.9, to promote stratification after backwashing. This minimizes desorption and premature breakthrough that can result from mixing activated carbon particles with adsorbed compounds, with activated carbon particles with smaller amounts of adsorbed compounds. Iodine and molasses numbers are typically used to characterize GAC. These numbers describe the quantity of small and large pore volumes in a sample of GAC. A minimum iodine number of 500 is specified for activated carbon by AWWA standards.

There are currently numerous existing GAC treatment facilities removing TCP including those located in:

Alhambra, CA, Burbank, CA Fresno, CA Glendale, CA Honolulu, HI Kaanapali, HI

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 7 of 21

Maui, HI Oceanside, CA San Jerardo, Salinas, CA Tustin, CA

GAC is considered the Best Available Technology (BAT) by the EPA and the State of California for the effective, efficient and economical treatment for removal of TCP. The EPA Technical Fact Sheet for 123 – TCP reflects that GAC is one of the only methods for successful removal of TCP from source water. The California Water Boards website on 123 TCP provides links and announcements for monitoring, detection and treatment of TCP see below. https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/123TCP.html https://www.waterboards.ca.gov/videos/video_pages/123tcp_utility_training.shtml For planning and layout purposes, Adsorption using GAC is the preferred TCP treatment alternative. Refer to Figure 3 for an example of typical equipment arrangement for TCP removal treatment of approximately 1,000 gpm. Turlock Wells Well 4 The Well 4 site is approximately 50 feet x 50 feet, east of and adjacent to Tully Road and located in low density single family residential zone surrounded by homes on three sides. Well 4 has a production capacity of 1,038 gpm with levels of TCP of 28 ppt. The Well 4 site is very small when considering accommodations necessary for TCP treatment, but a layout has been prepared as shown in Figure 4 which utilizes the existing parking area for locating the treatment vessels. If the available space is not adequate to locate the treatment onsite, another alternative involves pumping the Well 4 water to the Well 36 site. The Well 36 site has area available for constructing improvements for TCP removal treatment. After treatment for TCP, blending of the Well 4 water with the water produced from Well 36 would reduce levels of arsenic below the threshold limit, and the resultant water blend from the combined output of both wells would be in compliance with DDW water quality requirements. This alternative would require a 4,100 foot pipeline to be constructed from Well 4 site to the Well 36 site, but reduces full treatment needs for arsenic, to blending of the two sources for compliance. For the pipeline, there is an existing 20-foot back-of-lot easement that extends east of the Well 4 site approximately 1,300 feet. This easement continues south for approximately 910 feet to Joett Drive. Construction within this easement would be less expensive than within the street right-of-way since pavement replacement would not be required within the easement. This alignment option is feasible only if the Turlock Irrigation District approves granting of an easement to the

FIGURE 3 - TCP TREATMENT

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City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 8 of 21 City of Turlock. The other alternative would be to route the pipeline south along North Tully Road, and East along Joett Drive, which would result in the same overall pipeline length, but would be within the roadway for nearly the entire alignment, which results in increased construction, pavement, and traffic control costs. Refer to Figure 5 for a conceptual layout drawing of equipment and facilities for the combined Well Sites 4 & 36. Both pipeline alignment options are presented in the figure. Well 19 Well 19 is located in Donnelly Park near the intersection of Dels Lane and Pedras Road. Well 19 has available space for expansion of the existing footprint for treatment of TCP. Well 19 has a production capacity of 980 gpm with reported TCP levels of 66 ppt. A layout for the addition of GAC treatment equipment is shown in Figure 6. Construction of the treatment improvements may require removal of one or more trees and extension of the backwash drain line to Dels Lane to sanitary sewer. In addition, the need for chemical addition will require a small fiberglass chemical shed to house the sodium hypochlorite used in the process. Refer to Figure 6 for a conceptual layout drawing of equipment and facilities for Well Site 19. Well 29 Well 29 is located west of the intersection of Rockford Way and E. Hawkeye Avenue in the southeast corner of the Crowell Elementary School field. Well 29 has available space for expansion of the existing footprint for treatment of TCP. Well 29 has a production capacity of 1,240 gpm with reported TCP levels of 10 ppt. The well pump’s discharge header includes a set of two blind flanged tees that face westward as shown in Figure 7. The tees are separated by a gate valve which is currently open for flow-through of water which is currently not treated. Use of these tees and closure of the isolation valve will facilitate rerouting of the raw water westerly for treatment, and allow for return flow of the treated water back into the second tee on the main discharge header pipe. A layout drawing for the addition of GAC treatment is shown in Figure 8. Construction for the addition of the treatment equipment may require removal of one or more nearby trees, land acquisition from the school district, and extension of a backwash drain line from the new equipment to the existing sanitary sewer along Hawkeye Avenue. In addition, a small fiberglass chemical shed to house the sodium hypochlorite used in the process will be required.

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City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 9 of 21

Figure 7 – Well 29 Flanged Tees for Connection to Treatment

Refer to Figure 8 for a conceptual layout drawing of equipment and facilities for Well Site 29. Well 30 Well 30 is located southeast of the Wakefield Elementary School near the intersection of Burnell Avenue and S. Orange Street. This site is adjacent to the Wakefield Elementary School next to a field area of the campus, and there may be potential to acquire additional land if needed. Similar to the arrangement at Well 29, the well pump’s existing discharge header includes a set of two westward facing blind flanged tees separated by a gate valve on the main header as shown in Figure 9. The gate valve which separates the two tees is currently open for flow-through of untreated water. Use of these tees and closure of the isolation valve will facilitate rerouting of the raw water westerly for treatment, and allow for return flow of the treated water back into the second tee on the main discharge header pipe. Well 30 has a production flow of 1,013 gpm with reported TCP levels of 6 ppt. If this well requires treatment, a set of four GAC treatment vessels connected to the existing discharge header tees will be required to remove the TCP.

FIGURE 8

EAST HAWKEYE AVENUE

WELL 29

10' 20'0

TCP TREATMENT

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 10 of 21

Figure 9 - Well 30 Flanged Tees for Connection to Treatment

Refer to Figure 10 for a conceptual layout drawing of equipment and facilities for Well Site 30. Well 35 Well 35 is located southwest of the intersection of W. Monte Vista Avenue and North Tegner Road behind the Sherwin Williams Paint store. This well has a production capacity of 1,655 gpm with reported TCP levels of 23 ppt. As per Well 29 and Well 30, the well pump’s discharge header also includes a set of two westward facing blind flanged tees separated by an isolation gate valve; refer to Figure 11. However, the blind flange face of each tee is facing towards the existing electrical switchboard and motor control center, and will need to be removed and rotated 180-degrees to permit easterly routing to new treatment equipment located immediately east. Property rights will need to be confirmed, and additional property may need to be procured to allow expansion of the site and provide the necessary increased area to locate the new treatment equipment. There is a nearby existing surface mounted transformer and small electrical cabinets surrounded by a perimeter fence, and a perimeter fire lane which must remain clear at all times, both of which will limit the amount of additional property area which may be feasible for procurement. This site will require a set of six GAC treatment vessels to remove the TCP.

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WELL 30

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TCP TREATMENT

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 11 of 21

Figure 11 - Well 35 Flanged Tees for Connection to Treatment

Refer to Figure 12 for a conceptual layout drawing of equipment and facilities for Well Site 35. Well 36 Well 36 is located on North Soderquist Road in the southeast corner of Summerfaire Park. This well has a capacity of 2,013 gpm and Arsenic levels of 9.1 ug/l. This well also includes a pump discharge header equipped with a set of two blind flanged tees which face northward, separated by a gate valve on the main header. Refer to Figure 13 which shows the arrangement. Use of these tees and closure of the isolation valve will facilitate rerouting of the raw water northerly for treatment, and allow for return flow of the treated water back into the second tee on the main discharge header pipe. This well will require two reaction vessels and filter to remove the arsenic. The backwash waste is routed to the sanitary sewer, for the purposes of this evaluation this is an acceptable means of disposal and will require confirmation.

FIGURE 12

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City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 12 of 21

Figure 13 - Well 30 Flanged Tees for Connection to Treatment

Refer to Figure 14 for a conceptual layout drawing of equipment and facilities for Well Site 36. Alternately, as discussed earlier for Well 4, water from Well 4 could be used to blend and lower arsenic levels from the combined simultaneous output of Well 4 and Well 36. Arsenic treatment at Well 36 would then not be necessary, but instead replaced with TCP treatment equipment to handle the incoming water quality from Well 4. Well 38 Well 38 is located near the northwest corner of the intersection of Mountain View Road and W. Christoffersen Parkway. This well has a capacity of 2,793 gpm and arsenic levels of 12 ug/l. This well also includes a pump discharge header equipped with a set of two blind flanged tees which face southward, separated by a gate valve on the main header, but all located indoors within a large pump house. Refer to Figure 15 which shows the arrangement. Use of these tees and closure of the isolation valve will facilitate rerouting of the raw water westerly for treatment, and allow for return flow of the treated water back into the second tee on the main discharge header pipe. Modifications to the building may be necessary to extend piping from the existing tees to connect to the equipment, since the piping size is quite large at 16 inches, and will need to be routed to outside the building. Additional analysis will be necessary to determine if routing of piping can be designed to avoid interference with the existing rollup door, otherwise structural

WELL 36

FIGURE 14

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City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 13 of 21 review and modifications to the building relocation of the door will be necessary to maintain rollup door access.

Figure 15 - Well 38 Flanged Tees for Connection to Treatment

The City initially acquired between ½ to 1 acre for this site with plans for a future water storage tank and booster pump station to be co-located here. The backwash waste will be routed to the sanitary sewer. For the purposes of this evaluation this is an acceptable means of disposal and will require confirmation prior to implementation in design. Refer to Figure 16 for a conceptual layout drawing of equipment and facilities for Well Site 38. Cost of Design, Construction, and Operation Design and Construction Costs The following includes a list of main features and components that are required for design and construction at the well sites. For the combined Well 4 & 36 as listed below, the listed design and construction improvements reflect treatment of Well 4 raw water at Well 36, and a 4,100-foot raw water pipeline to convey the raw water to Well 36 as an alternative to separate treatment at each of the well sites. WELL 4 (1,038 gpm)

WELL 38

FIGURE 16

WEST CHRISTOFFERSON PARKWAY

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20' 40'0

ARSENIC TREATMENT

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 14 of 21

GAC Vessels (four vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Three Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

WELL 4 (1,038 gpm treated at Well 36) & Well 36 (2,013 gpm blended)

Improvements at Well 4 Well Pump Modifications (upsized bowl assembly, motor, and starter) Valves, Appurtenances Electrical, Instrumentation & Control Modifications Pavement Improvements at Well 36 GAC Vessels (four vessels) Backwash Tank (bolted steel) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Three Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

WELL 19 (980 gpm)

GAC Vessels (four vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Two Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement Tree Removal

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 15 of 21 WELL 29 (1,240 gpm)

GAC Vessels (six vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Four Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

WELL 30 (1,013 gpm)

GAC Vessels (four vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Three Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

WELL 35 (1,655 gpm)

GAC Vessels (six vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Five Cleanouts Two Sanitary Sewer Manholes Concrete Pads Pavement

WELL 36 (2,013 gpm)

Arsenic Treatment (two reaction tanks and one filter vessel) Backwash Tank (bolted steel)

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum FINAL October 23, 2018 REVISED January 15, 2019 Page 16 of 21

Well Pump Modifications (upsized bowl assembly, motor, and starter) Chemical Shed, Tanks, and Metering Pumps Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Three Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

WELL 38 (2,793 gpm)

Arsenic Treatment (two reaction tanks and two filter vessels) Backwash Tank (bolted steel) Well Pump Modifications (upsized bowl assembly, motor, and starter) Chemical Shed, Tanks, and Metering Pumps Electrical, Instrumentation & Control Modifications Process Piping, Valves, Appurtenances Backwash Piping Sanitary Sewer Extension with Two Cleanouts Sanitary Sewer Manhole Concrete Pads Pavement

Costs for engineering and construction have been summarized in Table 1 which also includes the Contractor markup, profit, contingency, administration and construction management.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum DRAFT October 23, 2018 REVISED November 26, 2018 Page 17 of 21

Table 1 – Wells 4, 19, 29, 30, 35, 36 & 38 Treatment Design & Construction Estimate City of TurlockWell Treatment Cost Evaluation

Well Flow Subtotal

(gpm) 30% 15%4 1,038 $112,000 $646,000 $55,000 $180,000 $139,250 n/a $1,020,250 $306,075 $153,038 $1,479,363 $1,591,363

4 & 36 1,038 $195,000 $646,000 $55,000 $340,000 $553,500 $179,098 $1,773,598 $532,079 $266,040 $2,571,717 $2,766,717 (4)

19 980 $119,000 $646,000 $55,000 $180,000 $123,500 $79,400 $1,083,900 $325,170 $162,585 $1,571,655 $1,690,65529 1,240 $168,000 $969,000 $65,000 $220,000 $196,700 $78,571 $1,529,271 $458,781 $229,391 $2,217,444 $2,385,44430 1,013 $114,000 $646,000 $65,000 $180,000 $120,250 $23,988 $1,035,238 $310,571 $155,286 $1,501,095 $1,615,09535 1,655 $179,000 $969,000 $65,000 $235,000 $337,450 $23,700 $1,630,150 $489,045 $244,523 $2,363,718 $2,542,71836 2,013 $150,000 $703,000 $83,000 $225,000 $169,250 $179,098 $1,359,348 $407,804 $203,902 $1,971,054 $2,121,05438 2,793 $151,000 $784,000 $95,000 $245,000 $249,000 n/a $1,373,000 $411,900 $205,950 $1,990,850 $2,141,850

Total Capital Cost for Treatment at All Wells: $14,088,178 (5)

Total Capital Cost (Combining Wells 4 & 36): $13,142,478 (6)

Notes1 ‐ Treatment equipment costs are based on costs provided by the vendor plus sales tax.2 ‐ For the 4 & 36 Wells description, this is the cost of the 4,100 foot 10‐inch pipeline from Well Site 4 to Well Site 36 in the roadway.

4 ‐ Assumes treatment for TCP from Well 4 only.  Arsenic treatment needs for Well 36 are met by blending with water produced from Well 4.5 ‐ Total capital cost for individual treatment at all wells.6 ‐ Total capital cost for individual treatment at wells 19, 29, 30, 35, and 38, with treatment for Well 4 blended at Well 36.7 ‐ Costs do not include pilot testing which may be provided for either treatment constituent for additional cost.

       • Well 19 cited at $992,500 per 1.33 acre lot currently listed for sale nearby, vs. 0.08 acres needed as additional area.3 ‐ Land Acquisition Costs ‐ includes the cost of land, engineering, acquisition and legal.  Land and acreage costs multiplied by 1.5 to account for engineeering, acquisition and legal costs.

Total Estimated Design and 

Construction Cost

       • Well 35 cited at $395,000 per 2 acre lot currently listed for sale nearby, vs. 0.08 acres needed for 100 ft. x 100 ft. net area for the overall site.       • Well 36 cited at $992,500 per 1.33 acre lot currently listed for sale nearby, vs. 0.16 acres needed as additional area.     Easement costs for pipeline from Well 4 to Well 36 are not included, and must be added if required.

Total Construction 

Cost

Construction Contingency

Profit, Bonds, Ins.

Land Acquisition (3)

Piping & Sitework (2)

Misc. Equip. & Electrical

Backwash Tank & 

Foundation

Treatment Equip. (1)

Engineering Design & Construction Assistance

       • Well 29 cited at $275,000 per 0.42 acre lot currently listed for sale nearby, vs. 0.08 acres needed as additional area.       • Well 30 cited at $1,559,220 per 7.8 acre lot currently listed for sale nearby, vs. 0.08 acres needed as additional area.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum DRAFT October 23, 2018 REVISED November 26, 2018 Page 18 of 21

Operation Costs Annual Operating Costs – GAC Treatment for TCP Removal Additional testing is required for the GAC system as recommended by the manufacturer. The differential pressure must be monitored on a weekly basis. Backwashing shall be initiated automatically once the differential pressure exceeds 4 to 5 psi as programmed, or may be initiated manually as well. Water with very low solids may not require a backwash before the GAC is totally spent. On a monthly basis a water sample must be obtained from one of the four sample ports for TCP testing. Over the lifespan of the media, sampling must begin starting with the top port of the primary treatment vessel, and eventually working down to the bottom port. Initial sample tests are expected to result in non-detect (ND) levels of TCP. As use of the treatment system progresses, sample results from the top port will eventually show detectable levels. Once TCP levels are detected in a sample, sampling must proceed the second sample test port. Once TCP levels are detected in a sample from the second port, sampling must proceed the third sample test port, etc. Once sampling from the fourth port (bottom port) shows detectable levels of TCP, sampling must be performed on the lag vessel starting with the top port. The GAC media in the lead column is typically replaced when the sampling from the top port of the lag column shows detectable levels of TCP, unless DDW permits a small leakage allowance (2 – 5 ppt of TCP) through the primary treatment vessel. Sampling is initially estimated to total approximately 20 samples per year per treatment site for the first year, which includes additional sampling operations staff may perform for verification, or if there is desire to sample multiple ports at the same sampling period. Once the consumption of the GAC has been characterized specific to the well’s water, sampling may be reduced by an estimated 20%. Annual Operating Costs – Oxidation/Filtration for Arsenic Removal Annual operating costs for arsenic treatment consist mainly of chemical consumption costs. Chemicals necessary for treatment include sodium hypochlorite, sodium bisulfite, and ferric chloride. Sodium hypochlorite is used as an oxidant and injected immediately upstream of the first reaction vessel, to convert arsenic to As(V). Ferric chloride is also injected upstream of the first reaction vessel to combine with As(V) precipitate. Sodium bisulfite is then used to reduce residual chlorine levels and injected after the first, but before the second reaction vessel upstream of the main filtration process where arsenic is ultimately filtered out. The amount of chemicals consumed are dependent upon levels of iron and arsenic in the raw water to be treated, and the volume of water to be treated. Estimated chemical usage for Well 38 as provided by Filtronics is estimated to be approximately $570 per day, based on 2,800 gpm of well production and continuous use.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum October 23, 2018 REVISED November 26, 2018 Page 19 of 21 Raw water which is classified as corrosive will require chemical addition to raise pH to produce a positive Langelier index prior to treatment. Typically this would involve addition of caustic soda, the need for which must be determined based on additional analysis beyond this memorandum. Annual Operating Costs – Pumping Energy Due to the increased pressure needs from the addition of treatment equipment, the well pumps will need to be modified to provide additional head to maintain current flow capacities. In addition, the well pump at Well 4 must be further upsized if treatment is combined at Well 36, to account for the additional head required to convey raw water from Well 4 to Well 36 via a 4,100-foot raw water pipeline. Table 2 below shows the estimated annual cost increase due to the additional pressure required for treatment.

Table 2 – Increased Pumping Energy Costs Well Production 

RateHydraulic Power

Electric Power

Average Electrical Cost

Annual Electrical

(gpm) (psi) (ft head) (HP) (kWh/day) ($/day) ($/yr)4 1,038 15.0 34.6 11.6 223 $25.14 $9,182

4 & 36 1,038 27.0 62.3 20.9 401 $45.25 $16,52719 980 15.0 34.6 11.0 210 $23.73 $8,66929 1,240 15.0 34.6 13.9 266 $30.03 $10,96930 1,013 15.0 34.6 11.4 217 $24.53 $8,96135 1,655 15.0 34.6 18.5 355 $40.08 $14,63936 2,013 10.0 23.1 15.0 288 $32.50 $11,87138 2,793 10.0 23.1 20.9 399 $45.09 $16,471

Required Pressure Increase

Assumptions:

1 - Usage is based on the current production rate of the well, running continuously for a year.

2 - Required pressure increase is based on equipment requirements, and assumed operating average of increased needs.

3 - Average pump efficiency of 78% is used.

4 - Motor efficiency of 93.5% is assumed, but will vary based on actual motor horsepower.

5 - Electrical cost of $0.1129 per kWh based on average industrial rate for the area.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum October 23, 2018 REVISED November 26, 2018 Page 20 of 21 Total Annual Operating Costs Total annual operating costs are presented in Table 3 below, which includes both treatment operating costs, and pumping energy costs.

Table 3 – Total Increased Annual Costs

Well Flow Constituent Equipment(gpm) Treated Operating Costs (1)

4 1,038 TCP $125,000 $9,180 $134,1804 & 36 1,038 TCP $125,000 $16,530 $141,530 (4)

19 980 TCP $125,000 $8,670 $133,67029 1,240 TCP $187,500 $10,970 $198,47030 1,013 TCP $125,000 $8,960 $133,96035 1,655 TCP $187,500 $14,640 $202,14036 2,013 Arsenic $125,000 $11,870 $136,87038 2,793 Arsenic $207,619 $16,470 $224,089

Total Operating Cost for Treatment at All Wells: $1,163,379 (5)

Total Operating Cost (Combining Wells 4 & 36): $1,033,859 (6)

Increase PumpingEnergy Costs (2)

Total Increased Annual Operating Cost

1 ‐ Equipment operating costs are based on costs by vendor for vendor recommended maintenance:      • Periodic sampling, and annual replacement of GAC for TCP treatment maintenance.      • Chemical usage of Sodium Hypochlorite, Sodium Bisulfite, & Ferric Chloride for arsenic treatment.2 ‐ Increased pumping energy costs for additional pressure requirements for treatment.3 ‐ Increased pumping energy costs for Well 4 & 36 combined includes additional head required at      Well 4 for the 4,100‐foot raw water pipeline routed to Well 36.4 ‐ Assumes treatment for TCP from Well 4 only.  Arsenic treatment needs for Well 36 are met by      blending with water produced from Well 4.5 ‐ Total capital cost for individual treatment at all wells.6 ‐ Total capital cost for individual treatment at wells 19, 29, 30, 35, and 38, with treatment for Well 4      blended at Well 36.

City of Turlock – Arsenic/TCP Treatment Project Technical Memorandum October 23, 2018 REVISED November 26, 2018 Page 21 of 21 Operations Staff Requirements We have assembled an estimate of City operator labor activities and hours required to maintain the new treatment equipment. Table 4 and Table 5 below represent the estimated number of staff hours, and frequency to perform recommended routine inspection and maintenance activities. City staff operations costs are not included in this memorandum and are subject to staffing availability, labor rates, operator grade levels, and City maintenance protocols.

Table 4 – Operations Labor Hours Estimated for TCP Treatment

No. Description No. of  Hours Staff Hours Frequency Hours perStaff year

1 GAC Filter Media Inspection 2 4 8 twice yearly 162 GAC Filter Media Replacement Oversight 1 4 4 yearly 43 GAC Tank Inspection 2 4 8 twice yearly 164 Meter, Valve, and Instrument Maintenance 1 8 8 quarterly 325 Settled GAC Removal 2 8 16 yearly 166 Regular Site Visit for Monitoring 1 2 2 3 times/wk 312

396Total Annual Maintenance Hours

Wells 4, 19, 29, 30 & 35 Each SiteEstimate of Average Maintenance Hours per Site per Year Due to Treatment

 

Table 5 – Operations Labor Hours Estimated for Arsenic Treatment 

No. Description No. of  Hours Staff Hours Frequency Hours perStaff year

1 Arsenic Filter Media Inspection 2 4 8 twice yearly 162 Arsenic Filter Media Top Off 2 4 8 yearly 83 Arsenic Filter Media Replacement 4 16 64 six years 10.74 Arsenic Tank Inspection 2 4 8 twice yearly 165 Meter, Valve, Reaction Vessel & Air Compressor Maintenance 1 8 8 quarterly 326 Chemical Systems Inspection & Calibration 1 4 4 monthly 487 Settled Arsenic Removal 2 8 16 yearly 168 Regular Site Visit for Monitoring 1 2 2 3 times/wk 312

458.7Total Annual Maintenance

Wells 36 & 38 Each SiteEstimate of Average Maintenance Hours per Site per Year Due to Treatment

Cost estimates presented in this memorandum are based on preliminary information only and are subject to change based on final criteria and design, and market conditions and pricing at the time of bid.