Recycled water surfaces once again

As statewide drought restrictions continue to impact much of California, local water and municipal officials are hoping to dive back into establishing a recycled water system on the Coastside.

Because of drought restrictions, the Coastside County Water District’s water supply from the San Francisco Public Utilities Commission has taken a hit this year. With climate change making local water sources less predictable, the district is hoping that recycled water, or wastewater that is treated, purified and delivered back to select customers, will be key to alleviating the impacts of severe drought.

After years of discussion among water-conscious planners, local agencies still have work to do to figure out the best approach and who will pay for it all. While it's still early days, CCWD General Manager Mary Rogren said that given the changes in water reuse regulations and technologies within the last decade, the district will re-examine how to treat and deliver recycled water to the coast.

The water agency’s board of directors will discuss potential next steps, such as hiring a consultant. And the district has its Water Reuse Advisory Committee to examine potential outcomes as well. Rogren said some of the newer and more expensive technologies, such as potable reuse, could be a stretch in the very near term and a project would likely have to be phased in over time.

Currently, recycled water is mostly thought of as a way to supplement groundwater or irrigation. According to the California State Water Board, 70 percent of all recycled water used in 2015 was for outdoor irrigation, a combination of agriculture (33 percent), landscape irrigation (19 percent), and groundwater recharge (18 percent).

Rogren said the district plans to partner with the city of Half Moon Bay for any future project. Half Moon Bay’s Land Use Plan encourages the development of a recycled water facility and outlines high-use customers like golf facilities, open spaces in residential areas and agriculture. At the City Council’s priority setting session last month, drought and recycled water was brought up, and potential collaboration was highlighted.

“Pipes are going to have to go through the city,” Mayor Debbie Ruddock said. “We might want to fund a piece of the process. They would probably buy treated sewage from (Sewer Authority Mid-coastside), but they have made a decision already to move forward as a lead. We want to be engaged with that to make sure it serves the interest of the city.”

Any collaboration will likely involve SAM. SAM General Manager Kishen Prathivadi said the sewer agency is always ready to pursue recycled water, but it’s up to CCWD to initiate the process. The upgrades required depend on the customer, Prathivadi said. To have potable recycled water, the SAM wastewater treatment plant would need costly infrastructure upgrades.

He noted that it’s important for SAM to get a system up and running sooner rather than later, as he expects the California State Water Quality Control Board to soon implement regulations requiring sewer agencies to reduce discharge into the ocean. Currently, SAM discharges all of its water into the ocean.

“That’s why it’s important for SAM to have this recycled water,” Prathivadi said. “We’ve been attempting it for quite some time.”

Previous efforts to plant a recycled water system for the Coastside have stalled. In 2017, a consultant told SAM a recycled water system would cost $5.2 million, with annual maintenance costs of $273,000. The only customer for the water at the time was the golf course in Ocean Colony. SAM completed 25 percent of the design, but the project ultimately fell through. That same year, the city of Half Moon Bay sued the two other member agencies, Montara Water and Sanitary District and Granada Community Services District, over who is responsible for pipeline maintenance.

California has some of the largest recycled water programs in the country and uses approximately 728,000 acre-feet a year in recycled water, according to the State Water Resources Control Board. That’s likely to grow in the coming years. The state board’s Division of Drinking Water is set to publish criteria and standards for recycled water for direct potable reuse by Dec. 31, 2023.

Rogren pointed to the Silicon Valley Advanced Water Purification Center as a potential model for Bay Area water agencies looking to develop a recycled system. The center uses an array of technology to purify treated wastewater through a multimillion dollar partnership between Valley Water, the San Jose- Santa Clara Regional Wastewater Facility, and the cities of San Jose and Santa Clara. The plant is currently researching how to augment its groundwater supplies with purified water, called indirect potable reuse.

While the scale would be hard to replicate locally, Rogren hopes that the technology becomes more widely accessible, both for direct and indirect potable use.

“There are technologies that we’d like to explore, which would be the best situation for the Coastside,” Rogren said.?

Source: https://www.hmbreview.com/recycled-water-surfaces-once-again/article_c6f96500-c03f-11ec-a7fb-ab2a50139462.html

• By August Howell