Bloomberg has a feature up today about Dow Chemical’s Water Division and the broader efforts to turn sewage into a safe and acceptable source for water reuse, up to and including human consumption:
Recycled wastewater will probably be the single largest source of water for California over the next quarter century,” says Tim Quinn, executive director of the Association of California Water Agencies. “And it isn’t just happening here—the same goes for many water-strapped regions of the world.” San Diego recently announced plans to produce 33 percent of its water from recycled sewage by 2035, up from none today, and is designing a toilet-to-tap facility even bigger than Orange County’s. Governments in Australia, China, India, Israel, and Spain, and throughout the Middle East and sub-Saharan Africa have developed recycled wastewater systems for irrigation; many are beginning to convert their systems to make drinking water. Singapore has the largest program, producing a third of its potable water from sewage.
Importing water to places like Southern California and Texas has historically been cheap, but with climate change, extended droughts, and increasing stress on rivers and lakes, the economics of water are changing. Virtually every city in the world has to start rethinking the foundation of its water supply. “Not every city has an ocean, not everyone has good lakes and rivers,” Desai says. “But everybody’s got sewage.
From a technological perspective, the write-up focuses mainly on applications for RO membranes (with a Dow bent, of course).
Importantly, the discussion also acknowledges another part of the problem – the social, user-acceptance, side:
There’s one lingering hitch: the gross-out factor. Even given the desperation of drought, drinking your own waste is nobody’s first choice. “Accepting recycled wastewater is kind of like being asked to wear Hitler’s sweater,” says Paul Rozin, a social psychologist at the University of Pennsylvania who’s researched consumer response to toilet-to-tap programs. “No matter how many times you clean the sweater, you just can’t take the Hitler out of it.”