Carlsbad Desalination Plant: How It Works

The Carlsbad Desalination Plant will turn 50 million gallons of seawater a day into drinking water. Plant operators will draw in ocean water, pressurize it and force the salty water through dense filters. The filters will remove the salt and produce drinking water that will be treated and added to the local water supply. The San Diego County Water Authority has agreed to buy the water at set rates for 30 years. At the end of the contract, the water authority will assume the plant’s ownership.

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1. Plant pulls in ocean water from Agua Hedionda Lagoon.

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2. Salty water is sent to a series of filters that remove organic and inorganic material from the water.

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3. Water is forced through canisters that pull salt out of the ocean water.

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4. Minerals are added to desalted water that is then pumped inland.

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5. Briny discharge is mixed with untreated lagoon water and returned to the ocean.

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6. Drinking water pumped to San Marcos.

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The San Diego County Water Authority built a nearly 10-mile pipeline to carry the newly desalted water from the Carlsbad plant to a pumping station in San Marcos. From there it goes to the Twin Oaks Valley Water Treatment Plant where the water can be stored or mixed with other water before it enters the county’s distribution system.

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