Earth Equity News

World's Farmers Turn to Raw Sewage for Irrigation. By Fred Pearce, New Scientist, August 18, 2008. "As cities and industries suck up ever more of the world's scarce water…. Agriculture is destined to rely increasingly on recycling the contents of urban sewers, according to a new [50-city] international study [by the International Water Management Institute (IWMI)] of 'wastewater agriculture'. The good news -- for farmers at least -- is that the irrigation water from sewers comes with free fertiliser in the form of the nitrates and phosphates bound up in human feces. The bad news is that this coprological cornucopia is filling vegetables sold in city markets with heavy metals, pathogenic bacteria and worms. An estimated one-fifth of the world's food is growing in urban areas, with perishables like vegetables to the fore. But… [the study]… finds that often the only source of the essential irrigation water to grow many of those crops is city sewage. Half of urban fields are irrigated with sewage, suggesting that a tenth of the world's food is already grown this way. IWMI's director Colin Chartres warned this week: 'This figure is bound to increase as growing cities coincide with escalating food shortages to create a squeeze on agricultural water supply.''