Carlsbad: The Desalination Game Changer in the U.S.

The Carlsbad Desalination Plant is the largest desalination plant in the Western Hemisphere. Located in California with a relatively small footprint of approximately 5.5 acres, the plant provides 54 million gallons of clean water to 300,000 people - a complete game changer for desalination in the United States.

The project for the San Diego County Water Authority (SDCWA), provides a high-quality water supply which exceeds all state and federal standards for drinking water and is also sustainable.

The facility was not constructed without its share of challenges. The design and construction team faced numerous obstacles including regulatory and economic hurdles to deliver an environmentally-friendly water supply. Working with a cross-globe team also presented a myriad of hurdles as teams were working in different time zones and had diverse customary practices.

IDE Technologies was contracted by Poseidon Resources for the design, engineering, procurement, and support services, as well as operation and maintenance of the facility for 30 years. To design this plant, IDE leveraged its proven technologies that have been successfully implemented in previous SWRO mega plants. Using IDE’s cutting-edge technology, the Carlsbad plant implements a single-stage SWRO system for the seawater desalination process.

The design of the pressure center reduces energy consumption by some 8% and the pre-treatment phase is based on long residence time flocculation and coagulation of raw seawater, followed by deep bed gravity dual media filtration containing anthracite, sand and gravel.

The proprietary pressure center provides an ideal solution for large plants as it offers flexible operation, online maintenance, high availability, and reliability which are all critical to ensuring the continuous and cost-effective production of water. The Carlsbad plant is adjacent to the Encina Power Station and shares the existing intake and outflow systems. As environmental safety is a priority for IDE, efforts were taken to develop the project with environmental solutions which foster healthy communities and preserve the natural coastal resources and lifecycle. At all stages of the process, the company adopted mitigation measures to preserve the region’s valuable resources.

The increased salinity of the brine discharged to the sea does not have an adverse effect on the marine organisms in the vicinity of the discharge channel. After the brine is returned to the discharge channel - and prior to its discharge to the Pacific Ocean - the brine stream is diluted with the return flow from the power plant’s cooling water system ensuring that the region remains protected.

Large-scale seawater desalination plants in California are a relatively new occurrence. Given the high value of real estate in the area, there are spatial challenges as well as hindrances with construction and design.

The Carlsbad Desalination Plant provides San Diego County with a locally-controlled and sustainable supply of high-quality water and generates more than $50 million annually to the regional economy.

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