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East County breaks ground on wastewater recycling plant

Water districts in East County today broke ground on a water recycling plant that they say will provide 11.5 million gallons a day of purified wastewater. KPBS Science and technology reporter Thomas Fudge has more.

People wearing business suits and hard hats broke ground Wednesday in Santee for the East County Advanced Water Purification Plant.

It’s part of a plan of four East County water agencies to take wastewater, that's now treated and dumped in the ocean, and turn it into water that’s clean enough to drink.

The water recycling plant is expected to provide 11.5 million gallons a day of purified wastewater for East County ratepayers.

“This project will create 30 percent of our water supply needs," said Alan Carlisle, the outgoing general manager of the Padre Dam Municipal Water District. "It will be sourced locally. It will not be imported from hundreds of miles away from the Colorado River basin that is under stress, or from the delta in Northern California. So it’s significant from that standpoint. It’s a local, reliable supply of water."

Padre Dam is one of four agencies that have created a Joint Powers Authority (JPA) to build and finance the water recycling project.

Water purification plants force wastewater through very fine filters. Any remaining contaminants are blasted with UV light and mixed with hydrogen peroxide.

After the East County wastewater has been treated in the new plant, it will be mixed with the region's drinking water supply in Lake Jennings, then be treated once more before being distributed as potable water.

Wastewater recycling plants, however, are expensive. The one in East County will cost an estimated $950 million. Four years ago, a Padre Dam Water District engineer told KPBS the estimated cost was around $460 million. But Carlisle said things have changed in the intervening years.

“The project has evolved," he said. "It’s expanded. We’ve added energy recovery. We’ve increased the size of the project. And of course, the impacts of the worldwide pandemic, supply chain issues, inflation. Those have all impacted the price."

But he added that once the new plant is built, there will be plenty of savings.

“In other words, if we do nothing, what are we going to pay for water?" he asked. "And what are we going to pay for wastewater services compared to what those services will cost if we do this project?”

In San Diego County, the city of Oceanside has already made purified wastewater a part of its water supply, and a much bigger project is being planned for the city of San Diego.

Deven Upadhyay, the assistant general manager for the Los Angeles-based Metropolitan Water District, said the East County water project is central to their goals.

“We provide about half of the water that is used in Southern California," he said. "But as we’ve seen climate conditions change, and we’ve seen growth patterns in the region, our board has taken a position that we need to increase self-reliance on local supplies that are developed within the region to reduce strain on imported supplies.”

He added that wastewater recycling is happening in a lot of places.

"We see that water purification is probably the biggest sector of growth for local supply development going forward," Upadhyay said.

Metropolitan is offering a financial incentive to East County that could cover $92 million of the cost of the plant. The MWD will pay the East County JPA $475 for every acre-foot of water it recycles, up to $92 million.

The vast majority of the cost of the water plant, $800 million, will be funded by loans from the state and federal governments. Carlisle said the loans come with interest rates as low as 1%.