![]() ![]() ![]() Outside water is still needed for potable uses. That’s the equivalent of the annual use of 16,000 San Franciscans, the company says. Built by the Australian company Aquacell, the system cleans 30,000 gallons of sewage, sink, shower, and other wastewater each day and uses it for irrigation and toilet flushing, saving an estimated 7.8 million gallons of water a year. The largest building with an on-site system is the Salesforce Tower, a 61-story office, hotel, and residential tower that opened in 2018 and is the tallest building in San Francisco. San Francisco’s recycling systems are not water neutral. “It’s a slow-moving process, but at the end of the day - considering all the scarcity - a lot of communities are going to pick this up as a way of having economic development while having water security.” “This is the future of water for everybody,” Newsha Ajami, director of Urban Water Policy at Stanford’s Water in the West program, said of decentralized water systems and recycling. ![]() By 2050, the UN estimates that 5 billion people could be subjected to water shortages. A recent study found that more than half the world’s lakes have lost significant amounts of water over the last 30 years. There are serious pressures on fresh water supplies around the world, with climate change exacerbating shortages. And decentralized projects are ongoing in Japan, India, and Australia. With the meagdrought and water crisis on the Colorado, the Rio Grande, and other Western rivers, “extreme decentralization” is making its way to other places in the American West, including Colorado, Texas, and Washington State. To demonstrate its technology, Epic Cleantec, a water recycling company, has even brewed a beer called Epic OneWater Brew with purified graywater from a 40-story San Francisco apartment building. Using recycled water for showers would eliminate another 20 percent of water demand, though the safety of that practice is being researched and is not yet permitted in San Francisco. Using it to flush toilets and wash clothes reduces demand for new water by about 40 percent. Recycling graywater alone can save substantial amounts of water. The process reduces the building’s imported potable supply by 40 percent. (Blackwater comes from toilets, dishwashers, and kitchen sinks graywater comes from washing machines, showers, and bathtubs.) The headquarters of the San Francisco Public Utilities Commission has a blackwater system, called the Living Machine, that treats its wastewater in engineered wetlands built into the sidewalks around the building, then uses it to flush low-flow toilets and urinals. So far, six blackwater and 25 graywater systems are using the technology, and many others are in the works. Proof of concept is unfolding in San Francisco, which in 2015 required all new buildings of more than 100,000 square feet to have on-site recycling systems. Eventually it’s hoped that buildings will be completely self-sufficient, or “water neutral,” using the same water over and over, potable and nonpotable, in a closed loop. It is, many experts believe, the future of water. By driving down demand for potable water, which is costly to filter, treat, and distribute, the units will help manage water more efficiently. The concept is to equip new commercial and residential buildings as well as districts, such as neighborhoods and universities, with on-site recycling plants that will make water for nonpotable use cheaper than buying potable water from a centralized source. While centralized water reuse for nonpotable purposes has been around for decades, a trend called the “extreme decentralization of water and wastewater” - also known as “distributed water systems,” or “on-site” or “premise” recycling - is now emerging as a leading strategy in the effort to make water use more sustainable. Just as natural systems use and reuse water repeatedly in a cycle driven by the sun, he said, “we now have technologies to enable us to process and reuse water over and over, at the scale of a city, a campus, and even an individual home.” “There is no reason to only use water once,” said Peter Fiske, the executive director of the National Alliance for Water Innovation, a division of the Lawrence Berkeley National Laboratory, in Berkeley. The system will clean the water with membrane filtration, ultraviolet light, and chlorine, and then send it back upstairs to be used again for nonpotable uses. There, this unit, called a OneWater System, will be installed in the basement, where its collection of pipes will take in much of the hotel’s graywater - from sinks, showers, and laundry. In downtown San Francisco, in a cavernous garage that was once a Honda dealership, a gleaming white-and-blue appliance about the size of a commercial refrigerator is being prepared for transport to a hotel in Los Angeles. ![]()
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