In its effort to establish a new, drought-proof source of water that could serve a half-million Southern California homes, the Metropolitan Water District on Thursday, Oct. 10 unveiled a $17 million pilot plant that will bring wastewater to drinkable standards.

Water from the trial project in Carson will not be piped to customers – it will be put back with regularly treated wastewater and pumped into the ocean.

But it’s a key step toward construction of a working plant that would reduce the region’s dependence on imported water.

“Mother Nature doesn’t just give us water – she recycles the water,” said Rep. Grace Napolitano, D-Norwalk. “We do it technologically.”

Napolitano, a longtime advocate for recycling water, was among a host of speakers at Thursday’s grand opening of the pilot plant. Some 300 water officials, elected officials and environmentalists attended.

Like a similar project in Orange County that already recycles enough wastewater to serve about 350,000 homes, the Carson project filtration system would use reverse osmosis as a key part of the purification process. As in Orange County, the resulting potable water would be used to recharge groundwater basins.

But Metropolitan officials also foresee the possibility of piping purified wastewater directly to customers in a process some dub “toilet-to-tap,” skipping the step of first putting it into the ground – or into a reservoir for mixing with other water supplies, as is done in San Diego.

So far, nowhere in the state has such a direct potable reuse system. In fact, California doesn’t yet have a process for approving such a plant.

“We want to help establish that process in the state,” said John Bednarski, Metropolitan’s chief engineer. “We’re kind of leading the way.”

While the trial project will produce 500,000 gallons per day, the full-size plant as envisioned would purify 150 million gallons. Estimated cost of a final plant is $3.4 billion, with construction beginning as early as 2024 and completion as soon as 2027 if all goes smoothly with the pilot, Bednarski said.

Follow the leader

The state’s 2011-2015 drought underscored Southern California’s vulnerability to inadequate water supplies. The four-year stretch was California’s driest on record, with some experts predicting that climate change will make such extreme droughts more common.

Southern California relies on the Metropolitan Water District to import 45% of the water supplied to 19 million residents in six counties. New local sources of water provide buffers against both local droughts and decreased availability of flows from Northern California and the Colorado River.

The Orange County Water District has been a leader in recycling wastewater for potable use, launching its plant operations in 2008.

After purifying the water at its Fountain Valley plant, it pumps 100 million gallons into the groundwater basin daily. Member water agencies then draw the water back out, give it final treatment and pipe it to customers.

Already billed as “the world’s largest water purification system for indirect potable reuse,” the Orange County system is about to undergo a $292 million expansion that would increase its daily capacity to 130 million gallons a day.

That would allow potable recycled water to serve 1 million people – nearly a third of the county’s population. Construction is expected to begin before the end of the year, with completion in 2023.

The cost of Orange County’s purified wastewater is $602 an acre-foot (326,000 gallons), far cheaper than imported water at $1,100 an acre-foot, according to Orange County Water District statistics.

The cost of purified water that would be produced at the Carson plant is pegged at $800 an acre-foot – but the 60 miles of new pipeline needed to distribute it would bring the cost to $1,800, according to Bednarksi.

But it would still be worth it because of the hedge against drought and against earthquakes shutting down import lines, he said.

Desalination plans?

Opponents of desalination plants proposed for El Segundo, Huntington Beach and Doheny Beach have pointed to the Carson proposal as one reason the desalting approach isn’t needed.

But Mickey Chadhuri, Metropolitan’s assistant chief of operations, doesn’t see it that way.

“There’s still plenty of room for local projects,” he said.

Bednarski, meanwhile, dismissed concerns that the Carson project could jeopardize the availability of Metropolitan subsidies for local water projects such as desalination plants.

“They’re two separate pots of money,” he said.

Current plans for the Poseidon plant are contingent on the project receiving a Metropolitan subsidy, with the El Segundo and Doheny proposals expected to also seek such assistance.

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