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• Installation of treatment facilities at Well 5/6 site is feasible but has challenges including extremely tight access for operational activities, minimal room to expand if additional treatment is needed for future regulations, visual impacts to school and nearby residents, increased schedule risk for CEQA, permitting, and public outreach, and challenging construction. • If the treatment vessels at Well 5/6 site were placed in a building it appears there would be room to accommodate IX treatment, but not GAC treatment. The building would result in additional capital costs (approximately $2 million) and the challenges described above would be heightened. • Installation at Well 8 site offers many benefits including good operational access, room to expand, minimal visual impacts, and less schedule risk due to simplified CEQA, permitting, pu blic outreach, and construction. However, since Well 8 is within the Operations Service Center grounds, improvements would be required to accommodate the City's current non water -related operational use of the area. • Consolidating PFAS treatment at the Well 8 site (i.e. treatment for Wel I 5, 6, and 8 all occuron the site of Well 8) can el i mi n ate con cem s with the Wel I 5/6 site, but requ fres additional capital cost for a pipeline from Well 5/6 to Well 8 (approximate addition of $3 million) and potentially a retu rn pipeline (approximate addition of $2 million). Modification of Well 5/6 pumps and additional energy costs may also be realized. Additional hydraulic modeling is requ fired to refine the scope and cost of piping improvements. Consolidating PFAS treatment at Well 8 does offer additional benefits including consolidation of chloramination and fluoride dosing to Well 8 (eliminating chemicals from the Well 5/6 site which is near homes and a school), simplified repair and replacement improvements at Well 5/6 for non PFAS related components, and potential phased installation of PFAS treatment capacity while maintaining well pumping redundancy. Along with the PFAS treatment feasibility study, Carollo Engineers also performed an assessment of Well 5/6 and Well 8 to recommend improvements that are required to extend the overall useful life of the existing facilities. Technical Memorandum 1 of the July 2020 Water Quality Evaluation includes the details of the assessment and is located at the following link: Water Quality Evaluation. The following summarizes well site improvements included in the PFAS Treatment Project: • Replacementof the following would be required: Well 6 pump/motor, chemical disinfection systems, and electrical distribution and control equipment. • Building modifications and ventilation system replacement. • Site security improvements such as newfencing consistentwith the City's current Risk and Resiliency project. Zone 7 Activities The following provides a summary of Zone 7 activities and coordination related to PFAS: Page 6 of 9