Desalination and Water Recycling Needed to Increase Bay Area Water Supply

In an ongoing drought exacerbated by climate change, the Bay Area needs to look toward two technologies to secure adequate drinking water supply: desalination and wastewater recycling, according to an analysis by the San Francisco Examiner.

June 9, 2022, 12:00 PM PDT

By Irvin Dawid


California, in year three of its latest drought, has already set a dryness record in the first four months of 2022. 

“In data released Monday [May 9], NOAA's National Centers for Environmental Information found January through April precipitation in the state was the lowest on record dating to 1895,” wrote meteorologist Jonathan Erdman for The Weather Channel on May 13.

...California's two largest reservoirs are at “critically low levels,” according to the May 5 Drought Monitor summary. Shasta Lake is at its lowest early May level since the drought of 1976-77, while Lake Oroville is only 70% of its early May average.

New technologies needed

Jessica Wolfrom, a climate and environment reporter for the San Francisco Examiner, wrote on May 29 that more than conservation is needed to secure drinking water for the Bay Area as traditional sources will be insufficient due to climate change.

Many say the time has come to invest in technically feasible, though politically and environmentally complicated alternatives like purifying wastewater and sucking salt out of seawater to bolster stores.

[Italics added below].

“We need a fundamental transformation of where we’re getting water from,” said Adrian Covert, senior vice president of public policy at the Bay Area Council, an association of local businesses dedicated to economic development. “And really, the two options are recycling and desalination.”

Desalination

In 2009, “a coalition of some of the region’s largest water agencies, including the San Francisco Public Utilities Commission, the Contra Costa Water District and the Santa Clara Valley Water District...launched a pilot project in Pittsburg that processed brackish Delta water, proving desalination was technically feasible,” adds Wolfrom.

But shortly after the pilot ended, further action was stalled by the 2012 drought and a complex tangle of water rights that effectively killed the project’s ability to divert more water.

“Right now, desalination in the Bay Area is still at the drawing board phase,” said Covert. “It’s kind of on the back burner.”

Brackish desalination

Not mentioned in the source article is the City of Antioch’s Brackish Water Desalination Project that broke ground on February 19 last year and is scheduled to open in "18-to-24 months," according to an email from John Samuelson, the city's public works director on June 3. Antioch, pop. 115,000, the third largest city in Contra Costa County, is about five miles east of Pittsburg, also located on the Sacramento–San Joaquin River Delta.

“The project is a great example of the solutions available to many small-to-medium sized cities in California,” wrote Covert in an email on June 2.  He went on to distinguish between seawater and brackish water desalination.

“My comments to the Examiner were with regards to large scale oceanic desalination, whereas the Antioch project is fairly modest (5,500 AFY) brackish desal project.”

Proposition 1, 2014

As Planetizen noted in January 2018 (“Desalination Projects Get a Big Boost in California”), the Antioch proposal was one of eight projects to receive grant funding from the $7 billion Proposition 1 water bond that was passed overwhelmingly by voters in November 2014.

An important characteristic of the vast majority of these projects: the facilities are for “brackish desalination, i.e., the “process in which 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.”

Interestingly, desalination wasn't mentioned in the summary of the proposition. The technology was included in the 'spending proposal' listed for water recycling:

  • $725 million for water recycling and advanced water treatment technology projects

It's shown in the legislative analysis included in the 113-page voter information guide [pdf]:

The bond includes $725 million for projects that treat wastewater or saltwater so that it can be used later. For example, the funds could be used to test new treatment technology, build a desalination plant, and build pipes to deliver recycled water.

Both types of desalination were included in the text of the proposition: Chapter 9. Water Recycling

(b) Contaminant and salt removal projects, including, but not limited to, groundwater and seawater desalination and associated treatment, storage, conveyance, and distribution facilities.

$10 million for Antioch plant

Kurtis Alexander of the San Francisco Chronicle reported on March 16, 2018 that Antioch would receive a $10 million grant from Prop. 1 towards the construction of a “$62 million plant that will desalinate water from the San Joaquin River.”

Though the city already taps the channel, the supply is often too salty for consumption because of inflows from San Francisco Bay, especially in the summer when Sierra snowmelt into the river is sparse.

“We’re going to partially drought-proof our community, which is rare in California,” said City Manager Ron Bernal.

However, desalination remains a very small part of the water supply pie in the state, and it comes overwhelmingly from one source.

About 2 percent of California’s drinking water comes from desalination, according to the state Department of Water Resources, which awarded the grants.

The top supplier is the $1 billion Carlsbad Desalination Plant in San Diego County, which opened in 2015 as the nation’s biggest desalting facility. It provides up to 400,000 people with treated ocean water in an area long dependent on water imports.

[See four related posts found under the tag, Carlsbad, and an August 2008 post by Nate Berg, one of Planetizen's first editors, on the approval of the facility by the California Coastal Commission.]

The Carlsbad plant supplies 50 million gallons [56,000 acre-feet per year (AFY)] of fresh, desalinated water to San Diego County while the Antioch plant will supply 5,500 AFY or less than one-tenth the amount, illustrating the aforementioned point made by Covert of the Bay Area Council.

Desalination controversy

“Critics of desalination, a process that uses reverse osmosis to remove mineral components from saline water, argue that it’s costly, energy-intensive and destructive to marine life, especially in coastal areas where biodiversity flourishes,” adds Wolfrom of the Examiner.

However, Glenn Farrel, executive director of CalDesal, a non-profit group whose mission is to “advance water desalination and salinity management,” believes that more water districts will adopt the technology.

“Given what we’re experiencing on climate change, the snowpack, our unpredictability and our prolonged droughts, I think it’s inevitable that communities even in the Bay Area will at least evaluate (desalination),” said  Farrel. “All indications suggest that this is going to be an ongoing part of the conversation.”

On the opposite side is Mandy Sackett, California policy coordinator at the nonprofit Surfrider Foundation.

“We live in California, in an arid climate — in an increasingly arid climate. Conservation needs to be a way of life before we move on to other methods that will have huge environmental impacts and maybe even exacerbate the drought,” said Sackett. Desalination “is such an energy hog — and it’s an environmental justice question, too, because that means we’re allowing polluting, dirty fossil fuel infrastructure to remain in our communities.”

The alternative technology

“While desalination has stalled, for now, water managers are turning to another, albeit, less palatable option: drinking recycled wastewater,” adds Wolfrom in the source article.

Also referred to as reclaimed water, recycled water is the runoff from storm drains and sewage pipes that has been purified, filtered and disinfected to meet stringent health standards.

Though desalination shares much of the same membrane and conveyance technology with wastewater recycling, the latter requires less energy and is cheaper to operate given that there are simply fewer salts to process, which is why many favor recapturing water over desalinating it.

Planetizen has nine posts tagged water recycling, from November 2015 to August 2021, with more to come.

Related:

Sunday, May 29, 2022 in San Francisco Examiner

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