Millions of Farmers Use Human Waste as Fertilizer

August 25, 2008 05:59 AM
by Isabel Cowles
More than 200 million farmers use raw sewage as fertilizer to save money, increase crop yields and improve irrigation.
Due to water shortages and rising costs of fertilizer, approximately 200 million farmers in Asia, Africa and Latin America use untreated human wastewater on grain and vegetable fields.
According to a report published by the International Water Management Institution (IWMI), “Even in areas where other water sources exist, small farmers often prefer wastewater because its high nutrient content reduces or even eliminates the need for expensive chemical fertilizers.” Wastewater sludge contains the same nutrients as commercial fertilizers: nitrogen, phosphorous, and potassium.
But the use of wastewater poses serious health threats: “farmers risk absorbing disease-causing bacteria, as do consumers who eat the produce raw and unwashed,” National Geographic reports. “Nearly 2.2 million people die each year because of diarrhea-related diseases, including cholera, according to World Health Organization (WHO) statistics. More than 80 percent of those cases can be attributed to contact with contaminated water and a lack of proper sanitation.”
Nevertheless, WHO water health expert James Bartram says that it would be unrealistic to prohibit the practice: “Overly strict standards often fail. We need to accept that across much of the planet, waste with little or no treatment will be applied to agriculture for good reason,” he says.
Volume 3 of the WHO’s 2006 guidelines for the safe use of wastewater notes that “Excreta and wastewater use schemes, if properly planned and managed, can have a positive environmental impact, as well as produce fish and plants.”
Although the use of human wastewater does not generally occur in developed countries, farmers across the United States have increasingly returned to manure as an alternative to chemical fertilizer.  A 2007 article in USA Today reported that the cost of nitrogen fertilizer “has more than doubled in the past four years, in part because of the rising cost of natural gas needed to make it.”

Related Topic: The debate over organic farming


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