Recycling Projects to Save Millions of Gallons of Drinking Water

July 24, 2019

Project transforms dirty groundwater into clean steam to heat downtown buildings

A San Francisco, Calif., groundwater recycling project plans to save 30 million gal of drinking water annually by cleaning dirty groundwater for steam to heat buildings. 

According to the San Francisco Chronicle, a sewer system 50 ft below the Powell Street Bay Area Rapid Transit (BART) Station platform is home to the groundwater recycling project. The reverse osmosis system used in the project is the Desalitech Closed Circuit Reverse Osmosis (CCRO) system. Below is an image from the project announcement with Desalitech CEO Nadav Efraty and other project stakeholders.

Gordon Judd, general manager for Clearway Energy, operates Energy Center San Francisco, which installed a 1,000-ft pipeline and replaced sump pumps to transport groundwater to the Jessie Street plant instead of the sewer system. According to the San Francisco Chronicle, $3 million was invested into the treatment system to scrub brackish water and debris off the pipes. 

He said water needs to be cleaner than drinking water before it can be boiled for steam, which incited the scrubbing equipment investment. According to the San Francisco Chronicle, the Clearway Energy started the recycled water process this year and is on track to save 30 million gal of drinking water. 

“We thought, ‘Isn’t there a way to tap that (groundwater) and use it for something useful?’” Judd said to the San Francisco Chronicle

Prior to the recycling project, BART officials treated the groundwater in the sewer system as a nuisance and a potential flooding risk. According to the San Francisco Chronicle, the city pumped millions of gallons of water into the sewer system each month for decades.