World set to use much more wastewater

Alister Doyle in Reuters: The world is set to use far more treated wastewater to help irrigate crops and feed a rising population as fresh water supplies dry up, a team of U.N.-backed experts said on Thursday. A study led by Japan's Tottori University and U.N. University's Canadian-based Institute for Water, Environment and Health (UNU-INWEH) forecast "a rapid increase in the use of treated wastewater for farming and other purposes worldwide".

It did not forecast volumes, saying that many nations lack data on sewer and drain water. Of 181 nations studied, only 55 had information on wastewater generation, treatment and re-use. Many governments and companies have so far overlooked the economic potential of vast amounts of wastewater, UNU-INWEH director, Zafar Adeel, said.

North America generates about 85 cubic km (20 cubic miles) of wastewater every year, of which about 61 cubic km is treated, roughly the amount flowing over Niagara Falls, and only four percent of that is re-used.

Wastewater also often contained nutrients such as potash, nitrogen and phosphorus which saved fertilizer costs, the study published in the journal Agricultural Water Management said. "Properly treated, wastewater is a huge economic resource," Adeel told Reuters....

Recycled water overflow from Aquacycle thickener, shot by Peter Craven, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license