Dependence on treated wastewater set to rise: study

A study led by Japan's Tottori University and UN 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 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 fertiliser costs, the study published in the journal Agricultural Water Management said.

"Properly treated, wastewater is a huge economic resource," Adeel told.

However, many developing nations cannot afford the equipment to treat wastewater even though recycling it can be cheaper in the long term than pumping water from deep aquifers, the report said, and, in Pakistan, like many other emerging economies, large areas are irrigated with mostly untreated wastewater.

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