Brackish Water Desalination: How is it different than Ocean Desalination? And is Brackish Water easier to desalinate into drinkable water?

California water supply gets $34.4M boost: 8 desalination projects get grants

California water officials have approved $34.4 million in grants to eight desalination projects across the state, including one in Antioch, as part of an effort to boost the water supply in the wake of the state's historic, five-year drought.

From article, (Water experts say it’s not surprising that the state is throwing more money behind projects that don’t rely on seawater.
“More communities are looking at brackish deals because it’s less expensive, it can have fewer environmental impacts and it isn’t limited to coastal communities,” said Heather Cooley, water program director for the Pacific Institute, a nonprofit research organization in Oakland.
Three projects were awarded $10 million each to help with construction. Among them is the Antioch Brackish Water Desalination Project, which is estimated to cost $62.2 million. The city already takes water from the San Joaquin River on the Antioch waterfront as it is flowing from the Delta into San Francisco Bay and uses it as part of the water supply for 110,000 people. But in the summer and fall months, when less Sierra snow is melting and less freshwater is flowing into the Delta, the water becomes too salty to drink.
In brackish desalination, salty water from a river, bay or underground aquifer is filtered for drinking, rather than taking ocean water, which is often up to three times saltier and more expensive to purify. Brackish desalination is growing faster. As of 2013, there were roughly 24 brackish plants in California, which produced about 96,000 acre-feet of water a year. Another three were in design or under construction, with 9,000 acre-feet more, and 17 were proposed with 81,000 acre-feet capacity.

The Alameda County Water District opened a brackish desalination plant in Newark that has been desalting about 14,000 acre-feet of water a year since 2013 — about 20 percent of the district’s supply.

“Technological advancements are happening all the time,” said Kelley. ” And the cost of water keeps going up, so the cost of desalinated water isn’t as out of proportion.”

Under the plan, the city would build a desalination facility at its existing water treatment plant to generate 6 million gallons a day of freshwater. The 2 million gallons of brine left over each day would be sent through a new 4-mile-long pipeline to the Diablo Wastewater Treatment Plant near Pittsburg, where it would be blended with treated sewage that already is pumped back into the bay.

The other projects that received $10 million each are the Doheny Ocean Desalination Plant in Orange County, which would drill slant wells under the ocean floor at Dana Point and is estimated to cost $110 million, and the North Pleasant Valley Desalter Project, a $32 million brackish water project in Camarillo, in Ventura County.

State officials still have $58 million in Proposition 1 funds to award for desalination projects. Among the projects looking for funding in the next round is a proposal by Cal-Am Water in Monterey County that state officials said needed more detail. The plan would drill slant wells under the sandy beach at Marina near a sand mining plant to generate drinking water.)

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