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State Eyes Treated Wastewater for Human Consumption

There’s no timetable for when wastewater might start flowing from household taps, but state water officials have begun work on standards that would assure the highly treated effluent is safe to drink.

By Guy Kovner, The Press Democrat, Santa Rosa, Calif.

Faced with a prolonged drought in most of the state and a burgeoning population, California is planning to augment natural drinking water sources with treated wastewater for human consumption.

There’s no timetable for when wastewater might start flowing from household taps, but state water officials have begun work on standards that would assure the highly treated effluent is safe to drink.

They acknowledged there are “knowledge gaps” to be filled before the standards are implemented. The gaps primarily relate to the “quantification of reliability” needed to ensure treated wastewater is as safe as water drawn from nature, according to a 540-page report released last week by the State Water Resources Control Board.

Randy Barnard, manager of the recycled water unit of the board’s Division of Drinking Water, said the report was intended to determine “if we could go down this path or not, (and was a) huge step forward.”

Nowhere in California is treated wastewater delivered to humans, and the report said that only water-poor areas in Texas and Namibia are currently using wastewater for human consumption on an emergency basis — a system known as “direct potable use.”

Eight California water systems, mostly in Southern California, are recharging groundwater basins with up to 200,000 acre-feet of treated wastewater per year and more than 20 such projects — known as “indirect portable reuse” — are in the works, including some in the San Francisco Bay area, Barnard said. An acre-foot is equal to 325,851 gallons.

“People are a little more comfortable with it because the (groundwater recharge) water goes through Mother Nature,” he said.

California is now reusing more than 700,000 acre-feet of treated wastewater a year, primarily for agriculture and landscape irrigation, he said.

The water board has set a mandate of increasing use of recycled water for all purposes by 200,000 acre-feet a year by 2020 and an additional 300,000 acre-feet by 2030.

California’s population is expected to grow from 38 million to 50 million by the year 2049, an increase that “will have a dramatic impact on the water needs of the state,” the board’s report said.

The ongoing drought, which remains extreme in most of Central and Southern California, accelerated the consideration of drinking treated wastewater, Barnard said.

The decision to use it will be made by cities and local water agencies, and not by the state, he said.

“It’s not our job to sell the public on it,” Barnard said.

The Sonoma County Water Agency, which delivers Russian River water to 600,000 customers in Sonoma and Marin counties, is not planning to recycle wastewater for human consumption, said Brad Sherwood, an agency spokesman.

Instead, the agency, which operates eight sewage treatment plants, plans to continue delivering wastewater for urban and agricultural irrigation throughout the county, he said.

Currently, 15,000 acre-feet of wastewater goes that route each year.

Grant Davis, the water agency’s general manager, is an advocate for direct potable use.

Hailing the water board report, Davis said in a press release it will help utilities around the state “address the serious water supply challenges California faces, especially during drought conditions.”

Davis is board president of WateReuse California, a trade association for water utilities, businesses and nonprofits focused on increasing water recycling.

California could already develop standards for wastewater recycling that would protect public health, but the regulations would be “very onerous,” requiring extra levels of treatment that may not be essential, Barnard said.

By waiting for experts to fill the “knowledge gaps” cited in the report, the state could ultimately set standards that are “more in line with the current technology,” he said.

©2017 The Press Democrat (Santa Rosa, Calif.) Distributed by Tribune Content Agency, LLC.