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10. Presentation on City's work plan to address Per-and Polyfluoroalkyl Substances (PFAS) and approve an agreement with Carollo Engineers in the amount of $437,374 to prepare a basis of design report for PFAS Treatment and Wells 5, 6, and 8 Rehabilitation Project Director of Operations and Water Utilities Kathleen Yurchak introduced the item and provided a brief overview of the presentation. Utilities Planning Manager Todd Yamello provided a regulatory status update for per-and polyfluoroalkyl substances (PFAS) and advised the focus of California regulations have been on Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) which are currently not regulated. He noted there are some recommended numbers for drinking water and hopes to have a final maximum contaminant level (MCL) by the winter of 2023. He reported on the seven chemicals that are the emerging focus of California regulation which includes Perfluorohexane sulfonate (PFHxS), Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA), Perfluoroheptanoic acid (PFHpA), Perfluorononanoic acid (PFNA) Perfluorodecanoic acid (PFDA), and ammonium 4,8-dioxa-3H-perfluorononanoate (ADONA). He reported within Pleasanton PFHxS has the highest concentration, PFBS, PFHxA, PFHpA, and PFNA have much lower concentrations, and PFDA and ADONA are not detected. Lastly, he reported there have been no notification levels or response levels issued by the state. Utilities Planning Manager Yamello provided a status update on PFOA and PFOS testing and noted there has not been a significant change detected. He reported PFOA for Well 5, 6, and 8 are below the state response level and PFOS is above the response level for Well 8 and below the response level for Well 5 and 6. He advised Zone 7 is also completing quarterly tests and receiving similar results. He anticipates a new Drinking Water Division (DWD) testing order in the 3rd Quarter, noted Well 8 has not operated since the beginning of testing, and noted Zone 7 is blending wells or treating their water. Utilities Planning Manager Yamello advised the City owns and operates three groundwater wells and which supplies 25% of the City's yearly water demands which is one well running full time. He advised to meet peak demands in the summer, the City must run two of the three wells in addition to what is received from Zone 7. He noted Well 5 was out due to motor failure and Well 8 was out completely resulting in the City needing to rely on Zone 7 to supply more water than normally used. He reported solutions include self-implementing a PFOS treatment at the City's groundwater wells, coordinating regional solutions, or reduce and/or eliminate the production from City wells and try offset with increased purchases from Zone 7 supply. He noted staff recommends self-implementing a PFOS treatment at the City's groundwater wells which puts the schedule in the City's control. Utilities Planning Manager Yamello presented the Work Plan to address PFAS which highlights checkpoints that allow the City to monitor the self-implementation process and prepare for regulations from the state. He advised a Condition Assessment of Wells 5, 6, and 8 has been completed and noted the wells are over 30 years old with many of the systems starting to reach their end of useful life. Utilities Planning Manager Yamello provided a brief overview of the Feasibility Study conducted by Carollo Engineers which included High, Medium, and Low Treatment Goals. He noted the High Treatment Goal would result in the least amount of treatment being done, the Medium Treatment Goal would meet current notification levels which are more stringent, and the Low Treatment Goal would take care of the family of PFAS chemicals currently being tested and bring them to non-detectable levels. He reported four technologies including Granular Activated Carbon (GAC), Ion Exchange (IX), Reverse Osmosis, and blending with some Zone 7 water were reviewed. He noted Reverse Osmosis was eliminated due to cost and blending with Zone 7 was eliminated because it was not technically feasible. He explained GAC is like filter cartridges in home refrigerators which pulls out the PFAS by absorption and while cheaper than Ion Exchange, more media is needed to treat PFAS. He explained IX essentially exchanges the PFAS ion that is in the water with one that is inert and while the treatment media is more expensive, less of it is needed. City Council Minutes Page 3 of 8 September 1, 2020