Water recycling company Epic Cleantech once demonstrated its technology by brewing a beer called Epic One Water Brew using purified miscellaneous water from a 40-story San Francisco apartment building.
With severe droughts and water crises on the Colorado, Rio Grande, and other western rivers, “extreme decentralization” is seeping into other parts of the American West, such as Colorado, Texas, and Washington. And decentralized projects are underway in Japan, India and Australia. Globally, freshwater supplies are under severe pressure as shortages are exacerbated by climate change.Recent study More than half of the world’s lakes have lost significant amounts of water over the past 30 years. The United Nations estimates that by 2050 he could have 5 billion people running short of water.
“This is the future of water for everyone,” said Nyusha Ajami, director of urban water policy at Stanford University’s Water in the West program on distributed water systems and recycling. “It will be a slow process, but ultimately, given all the scarcity, many communities will adopt this as a way to ensure economic development while ensuring water security.”
San Francisco’s recycling system is not water neutral. The largest building with an on-site system is his 61-story office, hotel, and residential tower, which opened in 2018 and is the tallest building in San Francisco, the Salesforce Tower. Built by Australian company Aquacell, the system purifies 30,000 gallons of sewage, sinks, showers and other wastewater every day for irrigation and flushing toilets, saving an estimated 7.8 million gallons of water annually. The company says this is equivalent to the annual usage of 16,000 San Francisco residents. Outdoor water is still required for drinking water. (Domino Sugar Mill in New York) redevelopment projectis currently under construction on the Brooklyn waterfront and will recycle 400,000 gallons of black water per day. )
The water utility, the San Francisco Public Works Commission, estimates that there are a total of 48 recycling systems in operation in the city, with another 29 projects planned. According to the agency, by 2040, the onsite water reuse program will save 1.3 million gallons of drinking water every day.
The technology already exists for these buildings to collect all the water and treat it to drinking standards. However, the safety of direct reuse of recycled wastewater is still being researched, and US regulations to date do not allow it. Experts say the country is at least five to 10 years away from fully circulating systems that reuse water on-site for both potable and non-potable purposes.
In contrast, centralized circulating water systems have been in use for decades and have also grown rapidly as a solution to water scarcity. For example, Orange County, California has the world’s largest water recycling facility. It purifies 130 million gallons of black water per day in a process called indirect potable reuse. Highly treated wastewater, which is normally discharged into the ocean, undergoes an advanced three-step purification process that includes microfiltration, reverse osmosis, ultraviolet light and hydrogen peroxide disinfection. Wastewater is injected into nearby groundwater, pumped and treated to drinking water standards by the local power company.
