The world’s growing flows of wastewater offer a largely untapped, potentially lucrative source of energy, agricultural fertilizers, and water for irrigation. The opportunities will increase as the annual volume of wastewater—now 380 billion cubic meters—expands by an estimated 51% by 2050, as populations and incomes multiply, says a team led by researchers at United Nations University’s Institute for Water, Environment, and Health. About 13% of global demand for fertilizer could be met by recovering nitrogen, phosphorus, and potash from wastewater; such use provides a bonus, diverting nutrients from waterways, where they can create harmful eutrophication. Sewage also offers an alternative energy source…..

Reaping Resources from Sewers, Science, Feb. 7, 2020