The Humanure Handbook
Composting crapper guide
This is the definitive source on composting crappers, from why to how, and yes, the scatological humor abounds. Yet this is a serious issue. Biosolids are recycled and used in the U.S. and around the world by governments and municipalities, and not always in the most responsible ways. Jenkins gives you the knowledge to do it yourself, and do it responsibly. The entire contents of this comprehensive guide are available as a free PDF download, and the Jenkins Publishing site offers up instructional videos, too. Very helpful when I constructed my own bucket toilet.
“We don’t want to eat shit!” they informed me, rather distressed (that’s an exact quote), as if in preparing dinner I had simply set a steaming turd on a plate in front of them with a
knife, fork and napkin. Fecophobia is alive and well and running rampant. One common misconception is that fecal material, when composted, remains fecal material. It does not. Humanure comes from the earth, and through the miraculous process of composting, is converted back into earth.
That’s also why humanure and urine alone will not compost. They contain too much nitrogen and not enough carbon, and microorganisms, like humans, gag at the thought of eating it. Since there’s nothing worse than the thought of several billion gagging microorganisms, a carbon-based material must be added to the humanure in order to make it into an appealing dinner. Plant cellulose is a carbon-based material, and therefore plant by-products such as hay, straw, weeds or even paper products if ground to the proper consistency, will provide the needed carbon. Kitchen food scraps are generally C/N balanced, and they can be readily added to humanure compost. Sawdust (preferably not kiln-dried) is a good carbon material for balancing the nitrogen of humanure.
A wide array of microorganisms live in a compost pile. Bacteria are especially abundant and are usually divided into several classes based upon the temperatures at which they best thrive. The low temperature bacteria are thepsychrophiles, which can grow at temperatures down to -10°C, but whose optimum temperature is 15°C (59°F) or lower. The mesophileslive at medium temperatures, 20-45°C (68-113°F), and include human pathogens. Thermophiles thrive above 45°C (113°F), and some live at, or even above, the boiling point of water.
If a backyard composter has any doubt or concern about the existence of pathogenic organisms in his or her humanure compost, s/he can use the compost for horticultural purposes rather than for food purposes. Humanure compost can grow an amazing batch of berries, flowers, bushes, or trees. Furthermore, lingering pathogens continue to die after the compost has been applied to the soil, which is not surprising since human pathogens prefer the warm and moist environment of the human body. As the World Bank researchers put it, “even pathogens remaining in compost seem to disappear rapidly in the soil.” [Night Soil Composting, 1981] Finally, compost can be tested for pathogens by compost testing labs.
Allow me to make a radical suggestion: humanure is not dangerous. More specifically, it is not any more dangerous than the body from which it is excreted. The danger lies in what we do with humanure, not in the material itself. To use an analogy, a glass jar is not dangerous either. However, if we smash it on the kitchen floor and walk on it with bare feet, we will be harmed. If we use a glass jar improperly and dangerously, we will suffer for it, but that’s no reason to condemn glass jars. When we discard humanure as a waste material and pollute our soil and water supplies with it, we are using it improperly, and that is where the danger lies. When we constructively recycle humanure by composting, it enriches our soil, and, like a glass jar, actually makes life easier for us.