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.

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. 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.

And again. And again.

"There is no reason to only use water once," said Peter Fiske, executive director of the National Alliance for Water Innovation, a division of the Lawrence Berkeley National Laboratory, in Berkeley. 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."

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 emerging as a leading strategy in the effort to make water use more sustainable.

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. By driving down demand for potable water, which is costly to filter, treat and distribute, the units will help manage water more efficiently. It is, many experts believe, the future of water. 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.

Read the full article about wastewater recycling by Jim Robbins at GreenBiz.