Shit has become so valuable that people have been hijacking sewer mains to suck out the sludge. Even with its low phosphorous content, urban fecal matter is much cheaper to harvest than operating the phosphorous mines that have become depleted anyway. Farmers and warmongers alike cry "More phosphorous!" But with bat populations (and their amazing guano) so low from white nose syndrome and the coprolites all mined out, where can they turn? Coprolites are mineralized feces of ancient animals, including dinosaurs--important to paleontologists as trace fossils that offer direct evidence of diet. In the 1850s coprolites were mined near Cambridge, England as a source of phosphates for farming. When the mines reopened during WWI the phosphates went into gunpowder instead of fertilizer. Last year, still scraping by to stay open, the Sedgwick Museum at the University of Cambridge sold its entire coprolite collection to a Chinese fertilizer manufacturer.
Our new toilet is a small version of the Rhizome Collective's brownfield commode. As a volunteer at the Radical Urban Sustainability Training workshop in 2008 I helped hand-build Austin’s first city approved, code compliant public composting toilet engineered by David Bailey. It took four years of review for the City to permit the structure. We built the toilet's walls with over a hundred bags of concrete mixed in wheelbarrows, poured into a plywood form along with demolition rubble gathered from the land. The design is divided in half so that humanure in one side can cure for a year while the other side is in use. The resulting pathogen-free nightsoil feeds the garden downhill from the toilet. The system produces free fertilizer while saving water (and the energy consumed in water’s production and treatment: "Austin Water Utility uses as much electricity as all other city departments combined"*).
In two years we will be able to use our humanure in the garden as compost. Meanwhile we are experimenting with a compost tea liquid fertilizer made of chicken and rabbit poop that has cured for a month, with some of our urine thrown in for good measure. If it sounds disgusting, wait till you bite into one of our huge, juicy tomatoes.
*Asher Price, "Green toilet wins city approval: Composting commode is first to gain official stamp," Austin American-Statesman, June 18, 2009.