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PROJECT GOALS The overall goal for the Wells 5, 6, and 8 Rehabilitation and PFAS Treatment Project (Project) is to rehabilitate the well facilities and add PFAS treatment to extend the useful life of the well facilities as reliable, locally controlled sources of water for the City. The City currently has a maximum allowable groundwater pumping allotment of 1,140 MG/year. The City typically operates two of the three wells, in addition to Zone 7 turnout supply, to meet peak summer demands. The City has a parallel Water Capacity Evaluation being performed by others and this study is estimated to be completed in early 2021. Expanding the production capacity of Wells 5, 6 and 8 is not included in this scope. WORKPLAN Implementation of the Project will occur in 3 main phases: 1) Basis of Design (this Scope of Work) 2) Final Design 3) Construction The Basis of Design phase includes the following major tasks, which are fully described in the following scope of work: • PFAS Treatment Siting Evaluation: This task will compare dedicated treatment at Well 5/6 and 8 vs. a centralized system at Well 8, and recommend the preferred option. • Wells 5, 6 and 8 Improvements: This task will identify improvements to Wells 5, 6, and 8 to extend the useful life of the facility and improve operator safety and facility operation. This task will be completed after the PFAS Treatment Siting Evaluation because the preliminary design at each well facility will depend on the PFAS treatment equipment siting. • Basis of Design Report: This task develops the Basis of Design Report, including taking recommended improvements at Wells 5, 6, and 8 to 10% level design drawings. The BODR will include permitting requirements, project schedule through commissioning, and a project cost estimate that will be used for budgeting purposes. • PFAS Process Design Confirmation: This task will include bench -scale testing with City groundwater to establish site-specific media replacement frequency and to refine O&M and life cycle cost estimates for PFAS treatment facilities and related improvements. This task will be performed in parallel with the other listed tasks. During the Water Quality Evaluation Project, the City and CONSULTANT made the following decisions to guide the project design: • The project shall reduce PFAS concentrations (EPA 537/537.1) to below reporting limits. • The project (including infrastructure sizing and site spacing) shall accommodate both Granular Activated Carbon (GAC) and Ion Exchange (IX) due to rapid developments in media technology. pw://Carollo/Documents/Client/CA/Pleasanton/_Proposals/Well 5, 6 and 8 PFAS Treatment and Well Improvements BODR/Exhibit A_Well 5, 6 and 8 PFAS Treatment and Rehabilitation Scope.docx PAGE 2of10