2025 Urban Water Management Plan

Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-18 EKI Environment & Water, Inc. DSRSD’s RWTF further treats a portion of the secondary effluent to produce Title 22 disinfected tertiary recycled water. During the dry season when recycled water demands are high, recycled water is produced using sand filtration and ultraviolet (SFUV) disinfection facilities, which have a treatment capacity of 16.2 MGD. In 2023, Pleasanton submitted payment to DSRSD to buy into increased recycled water treatment capacity at the RWTF, which increased Pleasanton’s capacity ownership to 2.7 MGD. DSRSD’s RWTF also includes microfiltration and ultraviolet disinfection facilities (MFUV) with a treatment capacity of 3.0 MGD. These facilities currently act as backup facilities for the SFUV facilities and are used during times of low and high demands. The SFUV facilities have less flexible startup and shutdown requirements, whereas the MFUV facilities have a wide turndown range; therefore, they are used during low flow periods. During high demand periods, the SFUV facilities are used, with the MFUV facilities serving as backup when units in the SFUV facilities are undergoing maintenance, repair, or replacement. DSRSD’s MFUV facilities were designed to produce recycled water suitable for both non-potable reuse and groundwater recharge, a potential future use that would replenish and improve local groundwater quality. MFUV construction was completed in 1999. The MFUV project is currently producing recycled water that meets California Title 22 requirements for unrestricted reuse and received approval for groundwater recharge from the California Department of Public Health (now under SWRCB as DDW) and RWQCB. Though Zone 7 and other retailers intend to further explore the option to purify recycled water through advanced treatment to enable potable reuse, the City has currently elected not to participate in the Tri-Valley potable reuse efforts. Treated effluent that is not recycled is discharged into the San Francisco Bay through a pipeline owned by LAVWMA, a joint powers agency created in 1974 by DSRSD, Livermore, and Pleasanton. The LAVWMA pipeline began operating in September 1979 and expanded in 2005. With a capacity of 41.2 MGD, the 16- mile LAVWMA pipeline conveys treated effluent from Pleasanton to the EBDA system in San Leandro for dichlorination, then discharge to the San Francisco Bay through a deepwater outfall. 6.5.2.2 Livermore Water Reclamation Plant Livermore owns and operates the LWRP, which treats wastewater collected from Livermore, Lawrence Livermore National Laboratory, and Pleasanton’s Ruby Hills housing development. From 2021 to 2024, the LWRP received an average daily flow of approximately 5.4 MGD. LWRP uses conventional primary and secondary wastewater treatment processes and applies tertiary treatment to produce recycled water. LWRP’s conventional wastewater treatment processes consist of the following: • Primary sedimentation where heavy organic solids are removed from the raw sewage and sent to solids stabilization and dewatering facilities • Secondary treatment utilizing the activated sludge process, which removes 85% to 95% of the remaining organic material after primary sedimentation • Disinfection using sodium hypochlorite to reduce the bacteria levels in the secondary effluent prior to disposal • Disposal of secondary effluent through the LAVWMA pipeline • Solids stabilization using anaerobic digestion followed by belt pressing for dewatering prior to beneficial reuse as alternate daily cover or land application LWRP’s tertiary treatment for recycled water consists of the following: • Mono-media filters, where 95% to 99% of suspended material is removed from secondary effluent