AGENDA TITLE:
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Adopt a Resolution Awarding Contract for the Well 6R and Well 14 GAC System Improvements, to Conco-West, Inc. DBA Conco West, Inc., of Manteca, California, ($3,361,200), Authorizing City Manager, or their Designee, to Execute Change Orders ($300,000) And Appropriating Funds ($3,661,200) (PW)
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MEETING DATE:
July 2, 2025
PREPARED BY:
Public Works Director
recommendation
RECOMMENDED ACTION:
Adopt a Resolution Awarding Contract for the Well 6R and Well 14 GAC System Improvements, to Conco-West, Inc. DBA Conco West, Inc., of Manteca California, in the amount of $3,361,200, authorizing City Manager, or their designee, to execute change orders in an amount not to exceed $300,000.
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BACKGROUND INFORMATION:
The Environmental Protection Agency (EPA) has established maximum contaminant levels for PFAS/PFOS constituents. It is anticipated the State of California will adopt the EPA’s limits as legally enforceable maximums. Per- and Polyfluoroalkyl Substances (PFAS) contaminants have been detected in small amounts at Well 14. This project will address the treatment requirements for PFAS prior to the federal compliance date of 2029. Without this project, Well 14 may experience an exceedance of the maximum limits that would result in it becoming inoperable.
In addition to the treatment installation at Well 14 to address PFAS/ PFOS, Well 6R is in need of additional treatment capacity. Well 6R’s existing granular activated carbon (GAC) installation was initially configured to remove dibromochloropropane (DBCP), a contaminant found at multiple sites in Lodi. In 2018, the State Water Resources Control Board, who regulates water systems in California, set a maximum contaminant limit for another compound, 1,2,3- Trichloropropane (1,2,3-TCP). This compound has been detected at Well 6R, as well as other sites in Lodi, and the recommended treatment for that contaminant requires a total of four GAC adsorbers, of which Well 6R currently has two.
For decades, GAC has been utilized at several well sites within the City to adsorb dibromochloropropane (DBCP) as well as other, potentially harmful constituents. The United States Environmental Protection Agency has also identified GAC as an effective technology for removing the recently discovered constituents of interest, PFAS, PFOS, & 1,2,3-TCP.
This project consists of furnishing and installing additional GAC filter vessels for additional treatment capacity at Well 6R, as well as a new GAC treatment system at Well 14, located at 1050 S. Stockton Street and 2206 Oxford Way respectively, as shown on Exhibit A and Exhibit B. The location of each of the project sites is shown on Exhibit C for reference. The GAC filter system improvements at Well 6R and Well 14 will require a total of six low profile tanks, carbon media, concrete pad, all required on-site piping and valving, fencing adjustments, and other necessary site improvements including the removal of a maximum of 5 birch trees at Well 14. The existing birch trees are located immediately to the west of the existing well site enclosure and will need to be removed to expand the facility in a reasonable manner.
The breakdown of the Engineer’s estimate and the two bids received on May 21, 2025 is shown below:
Above/(Below)
Bidder Location Base Bid Engineers Estimate
Engineer’s Estimate $3,000,000 Conco West, Inc. Manteca, CA $3,361,200 $361,200 Covenant Technical Solutions, Inc. Danville, CA $3,399,000 $399,000
Staff recommends awarding contract for the Well 6R and Well 14 GAC System Improvements, to Conco-West, Inc. DBA Conco West, Inc., of Manteca California, in the amount of $3,361,200, authorizing City Manager, or their designee, to execute change orders in an amount not to exceed $300,000.
STRATEGIC VISION:
5C. Infrastructure: Address deferred maintenance.
FISCAL IMPACT:
The project will have a minimal impact on total maintenance costs but will enhance the safety, reliability and efficiency of the water system. This project does not impact the General Fund.
FUNDING AVAILABLE:
Water Capital 56199000.77020