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NOVEMBER 2021 | 1 pw://Carollo/Documents/Client/CA/Pleasanton/_Proposals/Well 5, 6, and 8 PFAS Treatment and Well Rehab Final Design/Final Scope and Fee/Carollo Scope of Work Final EXHIBIT A Pleasanton PFAS Treatment and Wells Rehabilitation Project Final Design Scope of Work Project Background and Goals The City of Pleasanton (City) owns and operates three groundwater well facilities: Well 5, 6, and 8. The well facilities are used to pump the City’s annual groundwater allotment of 3,500 acre-feet (AF), which represents approximately 20 percent of the City’s total water supply. The other 80 percent of water supply is purchased from Zone 7 Water Agency (Zone 7). The City typically operates up to 2 wells simultaneously to meet peak demands during the summer months. A third well provides redundancy for facility maintenance or unplanned outages. It can also be operated in an emergency where available supply from Zone 7 is reduced. The City began testing its groundwater for PFAS the second quarter of 2019 in compliance with general orders issued by the Division of Drinking Water (DDW). Test results have shown that the City’s Wells 5, 6, and 8 facilities contain the presence of PFAS. Well 8 contains the presence of PFOS above advisory levels and as a result has not been operated since June 2019. The overall goal of the Project is to implement PFAS treatment and rehabilitate the City’s aging well facilities so they can remain reliable, locally controlled, sources of water. To meet this overall goal, the City has identified the following objectives: · Implement a centralized treatment system for Wells 5, 6, and 8 that can reduce PFAS concentrations below the City’s low treatment goal, which is defined as the consumer confidence report detection levels listed in the current DDW PFAS order (DW 2020-003-DDW). · Rehabilitate and/or replace Wells 5, 6, and 8 facilities to extend the useful life 30 years and be comparable to the useful life of a PFAS treatment system. · Plan for facility improvements to be expandable to accommodate potential future water treatment regulations. · Implement improvements in a timely fashion to increase the probability of commissioning facilities prior to required PFAS regulatory compliance and reduce the risk or needed time frame of purchasing supplemental water from Zone 7. Project Description The August 2021 Basis of Design Report (BODR) will serve as the basis for final design services. Recommended improvements listed in the BODR include but are not limited to: · Construct a new centralized treatment facility at the Operations Service Center (OSC) that provides PFAS treatment, disinfection, and fluoridation of City groundwater and room for expansion to accommodate potential future regulations. The recommended PFAS treatment media is granular activated carbon (GAC). However, the PFAS treatment system will be designed to allow the use of