The West Basin Municipal Water District (West Basin) is one of 26 member agencies of the Metropolitan Water District of Southern California (MWD) and provides wholesale water service to approximately 1 million people on the coastal plain of the Los Angeles area. West Basin also provides regional management of the area’s water resources through production and distribution of recycled water, extensive public education, and customer water conservation programs. These activities combined have significantly reduced West Basin’s dependency on imported water. To further that reduced dependency, West Basin is integrating desalinated ocean water as a portion of their local water supply portfolio through a “stepwise approach” which has included extensive pilot testing, demonstration testing of full-scale processes, conducting numerous technical studies, and development of a comprehensive program master plan.
Piloting: Over an eight year period, West Basin conducted ocean water desalination pilot testing at the El Segundo Power Generating Station in El Segundo, California and assessed the feasibility of turning ocean water into drinking water. Various water treatment technologies (i.e., High rate pre-screening, microfiltration/ultrafiltration, reverse osmosis, etc.) were piloted and extensive water quality monitoring of the raw ocean source water, discharge concentrate, and product water quality was performed. As a result of this testing, West Basin concluded that ocean water desalination could be a viable alternative water supply and additional research was needed to further develop it as a future water supply resource.
Demonstration Project: West Basin is currently conducting larger scale testing at their Ocean Water Desalination Demonstration Facility (OWDDF) at the SEA Lab in Redondo Beach, California. The OWDDF was completed in 2010 and has been operating continuously. The OWDDF is providing West Basin with the opportunity to build on the operational protocols and challenges from piloting to establish environmentally-effective and sustainable intake technologies, determine an approach to energy usage and optimization/minimization, develop process optimization protocols, determine operational requirements, establish target water quality goals, and evaluate concentrate discharge management options. The OWDDF includes an evaluation of passive screening and subsurface intake systems, energy consumption and optimization analysis and an intensive brine discharge study. The results of the two to three year demonstration project will be used as the foundation for development of a full-scale design, permitting, and operations approach.
Comprehensive Planning: West Basin continues developing ocean water desalination as a reliable and local water supply source and is defining and assessing the critical components of a full-scale ocean water desalination program. The assessment results and desalination program requirements are documented in this Ocean Water Desalination Program Master Plan (PMP).
West Basin’s Ocean Water Desalination Program Master Plan
The purpose of West Basin’s Ocean Water Desalination Program Master Plan (PMP) is to define the overall desalination program scope and the key project components. These critical components consist of supply availability, water demands, siting alternatives, intake and discharge facilities, treatment process engineering and technological requirements, conveyance and distribution requirements, system integration and treated water quality requirements, environmental and permitting requirements, power supply development, capital and O&M costs, project delivery, and operational requirements.
The PMP document is comprised of a number of technical memoranda (TM), which address each of the critical program components providing detailed narrative, analysis, calculations, exhibits, drawings, and conclusions. The PMP document is divided by TM such that each component can be referenced by section. This report division (and an objective of the PMP) is intended to be used as a technical study for the California Environmental Quality Act (CEQA)/Environmental Impact Report (EIR) process and in support of the basis of design development for the full-scale project. The PMP includes the following sections: