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Friday, July 29, 2022

'We Have The Technology': LA Plans To Recycle Wastewater Into Taps

 Instead of addressing California's crippling drought with network of desalination plants (a plan which actually had the support of Gov. Gavin Newsom until the state's HOA - aka the Coastal Commission - shot it down earlier this year), the city of Los Angeles and other agencies across Southern California are considering a plan to recycle wastewater into tap water.

An influent pumping station at the Water Replenishment District's advanced water treatment facility in Pico Rivera. (Irfan Khan / Los Angeles Times)

Just don't call it "toilet to tap" say proponents (or do, because that's what it is), who claim it's different from similar proposals in the late 1990s to use recycled water thanks to new technologies in water recycling.

The city of Los Angeles and agencies across Southern California are looking into what’s known as “direct potable reuse,” which means putting purified recycled water directly back into our drinking water systems. This differs from indirect potable reuse, where water spends time in a substantial environmental barrier such as an underground aquifer or in a reservoir. -LA Times

"There’s been a public health legacy where sanitary engineering practices and regulators considered sewage a waste, it was something to be avoided, something to be feared," said Brad Coffey of the Metropolitan Water District of Southern California. "Now that we have the technology … the public, the regulators, the scientific community has much greater confidence in our ability to safely reuse that water supply."

The plan hinges on the State Water Resources Control Bord, which legislators have tasked with developing a set of uniform regulations by Dec. 31 which would govern potable reuse.

Los Angeles, according to the report, "is wasting no time in readying projects that can launch once the regulations are passed."

A direct potable reuse demonstration facility near the Headworks reservoir just north of Griffith Park probably will be the state’s first approved direct potable reuse project, said Jesus Gonzalez, manager of water recycling policy at the Los Angeles Department of Water and Power. It will take advantage of recycled water produced by a facility in Glendale, but the water will not be added to the drinking water system just yet. However, it will serve as proof of concept, he said. -LA Times

"This is going to be the future of L.A.’s water, the future of the state’s water supply," said Gonzalez, who added that the Headworks project could come online within the next five years.

LA's plans are much bigger than that, however - as the city has set out to recycle 100% of its wastewater by 2035 per a pledge made by Mayor Eric Garcetti several years ago.

In order to achieve this, LA's Hyperion Water Reclamation Plant - which currently only treats wastewater so it's clean enough to release into Santa Monica Bay - must be completely converted into an advanced water purification facility which produces water that's clean enough to consume.

The Hyperion sewage treatment plant in Playa del Rey, on left, across from Dockweiler State Beach. (Christina House / Los Angeles Times)

The water - enough for 2 million people - would then be piped to vast aquifers under the southern part of LA County and the San Fernando Valley. Dubbed 'Operation Next,' the massive undertaking will cost upward of $16 billion and would be completed in 2058 - more than two decades after Garcetti's goal.

The Hyperion plant suffered a catastrophic flood just one year ago, which led to 17 million gallons of untreated sewage to be dumped into the oceancausing millions of gallons of drinking water to be diverted for uses typically served by treated wastewater. The plan is now back to normal operation.

"That spill did reinforce everybody, including us, that we do need to have monitors and alarms upstream of the wastewater plant to be able to identify any problems, whether they’re spills, whether they’re infrastructure issues," said Gonzalez.

Baby steps...

For now, a proof-of-concept for the Hyperion operation, a small-scale advanced purification facility is nearly complete. Constructed in partnership with LA International Airport, the plant will be able to crank out 1.5 million gallons per day of water for nonpotable uses, such as toilet flushing and cooling, according to LA Sanitation and Environment CEO Traci Minamide. It will come online in spring 2023.

"The technology is that good," said Shane Trussell, president and chief executive of Trussell Tech, which is involved in advanced water purification projects across Los Angeles, San Diego and other cities. "I expect by 2040 … most of the effluent in Southern California will be recycled or well on its way to being recycled."

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