by Dana Visalli
Humanure can be easily and safely composted and made completely safe to use as fertilizer. For the full details, consult The Humanure Handbook: A Guide to Composting Human Manure by Joseph Jenkins, available at your favorite bookseller or as a loan from the PSM office.
Briefly, the three critical elements to composting humanure are
1) Creating a compost pile that has the necessary carbon: nitrogen (C/N) ratio for aerobic bacteria to break the manure down into humus. The ideal C/N ratio for bacterial decomposition is 30:1. Humanure has a C/N ratio of about 10/1 (it is high in nitrogen), so it is necessary to add high carbon material like straw to the compost pile. When properly built, a humanure compost pile does not give off any offending odor.
2) Adequate oxygen. The bacteria that break down the manure are aerobic—they require oxygen to function properly. Oxygen is easily made available by using bulky, hollow material such as straw in the compost pile.
3) Heat. Aerobic bacterial action produces heat; compost piles can warm to 140 degree or higher. Complete pathogen destruction in the humanure is guaranteed by arriving at a temperature of 143 degrees F for one hour, 122 degrees for one day, or 115 degrees for a week.
4) Time. Letting the compost pile “cure” for a year after it has finished the aerobic decomposition will offer a guarantee that all potential pathogens are destroyed.
The end product of this decomposition process is humus—organic matter rich in critical nutrients, like the composted steer or chicken manure we purchase at the feed store. These nutrients give life to plants, which give life to us, and then they go back into the living soil in an endless cycle.
The Latin root for humus, humility, and humanure are all the same, and translates as “earth.” Re-integrating our lives with the endless cycling of nutrients and elements is an act of humility in that it brings us out of the imaginary world we create inside our heads and back down to earth, which is a good place to be.
Dana Visalli is a biologist living in Twisp, WA. He is the president of The Partnership for a Sustainable Methow (www.sustainablemethow.net) and the editor of The Methow Naturalist (www.methownaturalist.com)