Yes Magazine - What comes out of our bodies contains almost all of the nitrogen and phosphorous we ingest. Abe Noe-Hays, research director at the Rich Earth Institute, explains it this way: “When plants grow and produce food, that food is full of nitrogen and phosphorous. When we eat it, we rearrange the molecules, but the elements don’t go away; they come out dissolved in our urine. If we can return those elements to the soil, it really is giving back the very thing we took in the first place.”
Returning nitrogen and phosphorous to our waterways, however, is a different matter. Rain sweeps these nutrients off agricultural fields, away from newly fertilized lawns, out of wastewater treatment plants, and into groundwater and streams that lead to lakes and oceans. Algae and other water plants ingest these nutrients and flourish just like crops. These algal blooms deplete the oxygen that fish and aquatic organisms require, creating dead zones like those in the Gulf of Mexico and Chesapeake Bay. At least 15,000 water bodies in our country have poor water quality from excess nitrogen and phosphorous.
Fresh human urine looks weak but acts powerfully. According to Noe-Hays, it has a higher nitrogen-to-phosphorous ratio than cow manure. In one year, an adult can produce 125 gallons of urine, containing the equivalent of about eight pounds of total nitrogen and 0.8 pounds of phosphorous. That would fertilize enough wheat to make a loaf of bread every day of the year. Once urine enters the waste stream, it accounts for less than 1 percent of wastewater volume but three-quarters of its nitrogen and more than half of its phosphorous.
Urine diversion gained momentum across the Atlantic during the 1990s. Sweden pioneered the NoMix toilet and now has about 700,000 on-site sanitation systems, 60 percent of which serve residences. South Africa, China, Germany, the Netherlands, Switzerland, and Australia now showcase different systems, all in various stages of success.
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