How to compost humanure
In composting humanure, microbes do all the real work. Humanure requires no fossil fuels and less than 5% of the water used by flush toilets. I follow the system Joseph Jenkins describes in his Humanure Handbook. The toilet is a bucket under a standard toilet seat mounted on a plywood box. You can build one in a matter of minutes. “Flushing” is accomplished with a few handfuls of leaves (shredded is best), horse manure (dried is best), or any relatively fine mulch (generally referred to as brown material). Jenkins uses sawdust from local sawmills, which is easy for him to source in western Pennsylvania. So long as you use adequate brown material to cover newly deposited poop, there’s no odor.
In addition to the bucket, the system requires two compost piles, one for buildup and one for mellowing, which I wall in with scavenged wood pallets. I fill the buildup pile with buckets of fresh material. To do this, I move aside some topping brown material with a dedicated pitchfork, dump the bucket, and then replace the topping material. Then I rinse out the bucket with a hose and dump the water on the pile. If there’s odor, I add more brown material.
After a year, I use the dedicated pitchfork to move the buildup pile into a second pile, the mellowing pile. There the compost mellows for a second year.
After two years, humanure has transformed into nutrient-rich compost. I add it to the garden and the orchard, laying it down on top of garden beds, under the drip lines of trees, and to any plant that seems to want some extra nourishment. The received wisdom is to restrict the use of humanure to fruit trees, and to never use it near vegetables. While this rule is certainly necessary for raw sewage, it’s overkill for properly composted humanure.
To be safe, humanure must be properly composted. In practice this means it must reach a temperature hot enough to kill pathogens. It’s worth noting that cholera pandemics were a fact of life, even in the US and Europe, until quite recently. A disease that spreads when sewage contaminates the drinking water supply, cholera claimed tens of millions of lives in the 19th and 20th centuries. Even today, more than 100,000 people per year die from cholera; and global warming is expected to give the cholera bacteria a boost.
Cholera isn’t the only disease you can catch from sewage: feces from infected individuals can transmit other bacteria, parasitic worms and protozoa, and viruses. However, proper humanure composting eliminates these dangers. Fecal pathogens are killed by heat over time, and humanure piles heat up due to heat-producing thermophilic microbes— good bacteria. The hotter the pile becomes, the less time it takes for pathogens to die: “complete pathogen destruction should be guaranteed” if all parts of a compost pile are maintained at temperatures of 144°F (62°C) for one hour, 122°F (50°C) for one day, 115°F (46°C) for one week, or 109°F (43°C) for one month.13 This is the golden rule of humanure.
During the buildup phase, my pile holds steady at 110°F to 120°F no matter where I stick the compost thermometer. More importantly, the temperature in newly added five-gallon deposits climbs to 135°F to 140°F after two days, and stays up there a week or more. After three days at this temperature, essentially all pathogens in my newly added material will be dead. All additional time is insurance. Turning the material by pitching it from the buildup pile to the mellowing pile provides a second round of purifying heat. I once noted that two days after doing this turning, the temperature in the newly mellowing pile climbed to 155°F. It stayed above 152°F for over a week, and above 145°F for another four days.16 This turning also mixes surface material into the hot interior, helping to
ensure that all parts of the pile get hot. When my first pile was a few months old, I examined it with my nose. Our sense of smell is a direct connection to the microbial
world, after all; an unpleasant smell often indicates something that can make us sick. The pile was about four feet by three feet by two feet high. It had been about five days since I’d dumped a bucket. There were no flies, and it smelled earthy. With the pitchfork, I excavated down to the clay soil. The core of the pile, at several months old and well below the level of re-
cently added deposits, looked and smelled like regular compost: dark black leaf bits, a rich earthy smell, and bugs scurrying around. There were no visible turd remnants, and no offensive smells— even with my nose a few inches away. I reached in and grabbed a
handful of material from the bottom of the pile. It looked, felt, and smelled like dirt. Poop was transmuting into compost. I can’t overstress two key advantages of humanure: (1) it’s simple and cheap, requiring only a bucket, a thermometer, a tiny bit of knowledge, and a square yard of land per several families; (2) it transmutes disease-causing poop into valuable, healthy soil. As far as technologies for global development go, few would benefit the world’s poor more than humanure.
Globally, one in three people— 2.4 billion people— don’t have access to a decent place to poop. A billion of these people poop where they can— behind bushes, out the street. The rest poop first in buckets and then dump the buckets wherever, or else use “unimproved” latrines (a hole in the ground, or an outhouse on stilts with a hole in the floor).17 A billion additional people have access only to “improved” pit latrines, which are themselves a major groundwater contamination risk which will worsen with increased flooding from climate change.18 This picture is both inhumane and deadly, with contaminated drinking water directly causing an estimated 300,000 deaths per year and contributing to widespread disease and malnutrition, especially among young children. In India, over half of the groundwater and 80% of the surface water is contaminated by sewage, and 40% of women who drop out of school in India say it’s because there are no toilets in the schools.
Humanure composting provides a hygienic alternative. And because educated women have fewer children, humanure composting could even eventually help with overpopulation.
Humanure is safer than conventional waste treatment
The situation in the US, while better in some ways, is still far from perfect. In the US, 20% of households use septic tanks,21 which collect household and human wastes. After a short settling time with minimal anaerobic decomposition, this untreated effluent, still with a huge pathogen load, is simply introduced into the soil (or “leach field”). Like pit latrines, these systems often silently cause groundwater contamination. The other 80% of waste in the US is piped to sewage treatment plants, which fail occasionally, and have difficulty coping with storm water. In Los Angeles, for example, our beaches are routinely closed after rains due to the dumping of large volumes of untreated sewage. Even when all goes as planned, the process results in tonnes of toxic sludge. At the treatment plant, microbes are given only about two weeks to work at a temperature of approximately 95°F— not enough time and temperature to kill pathogens. The resulting “biosolids” are then sold to farmers and citizens. My dad used to put it on his lawn, and it smelled just like poop, which tells you something; also, the vast majority of biosolids are “Class B,” mean-
ing known to contain large pathogen loads.
Sewage treatment plants’ input streams also include detergents, industrial waste, persistent pharmaceuticals, and heavy metals such as lead and cadmium, along with other toxins. Persistent pharmaceuticals and heavy metals build up in soils, and some crops readily absorb them.23 Remediation necessitates removing the poisoned earth and trucking it “away.” Personally, I’d not apply biosolids to my land. We pay a high price for the convenience of flush toilets.
In our culture, poop is taboo,24 and for good reason: it can carry disease. But properly composted poop is no longer poop. It doesn’t look or smell like poop. It wouldn’t make you sick even if it did get into your food or water. The power of taboo, however, lies in its emotional intensity. Evidence alone won’t convince someone to relinquish a taboo. But time and familiarity will. Now that I’ve been composting humanure for several years, I can say that it quickly becomes not a big deal. Sharon tolerated this quirk of mine for the first three years. And then one day, she started using the leaf toilet, too. One man’s waste Time races on. The planet warms, the corporatocracy consolidates, wars rage. And here I am, writing about poop in detail. How can I justify this use of my time? I’m a mammal. I’m one man, tending my garden, coming back down to Earth. It takes time for good things to grow. I’m doing everything I can do within my particular situation, as fast as I can do it. And I’m old enough to know that patience is more effective than panic. I’m suggesting that humanure composting is actually deeply relevant to our looming predicament. Apart from the ecological
problems flush toilets cause, they’re a powerful symbol of our mindless disconnection from nature. We go about our business pretending that we aren’t animals, that technology has allowed us to transcend natural limitations. But no matter what we invent, we will always be nature. Composting my own poop reminds me of what sustains me, and of my place in nature. It reminds me where I come from, and where I’m going.
Composting without poop
You might not feel ready for humanure composting. Fear not: just keep a basic compost pile, without poop. Maybe someday you’ll try humanure. I also keep a worm bin, which is easy. It makes me happy to see the worms. There are piles of information out there on both basic composting and worm composting. But I personally find humanure composting to be a much deeper practice.
Practical tips for humanure composting
If you decide to try humanure composting, here are
some things I’ve learned which may help:
• Pick a shady spot for the pile.
• Use a compost thermometer.
• Keep a separate pitchfork for your pile. Don’t use it
for anything else.
• Kitchen and yard scraps can go into the pile.
Contrary to composting dogma, I compost any-
thing: meat, dairy, dead animals, pet poop. To keep
animals away, enclose your pile in 1/2-inch hardware
cloth (1/4-inch if you want it mouse-proof).
• You can compost toilet paper, tissues, and paper
napkins. Shredded paper and cardboard can be
composted if added a little at a time.
• You can compost sticks, but break them up into
small pieces first.
• Watch out for the plastic stickers on fruits and veg-
etables. It’s truly uncanny how plastic never breaks
down. Compost piles really demonstrate this.
• If your pile isn’t heating up, you do need to find out
why and correct the problem. Some possibilities:
too much carbon, not enough nitrogen; not enough
moisture; not enough oxygen. It is also possible
your pile isn’t big enough yet— heat seems to
require a critical mass. Experiment and you will find
the problem. After making a correction, it might take
a day or two before the temperature changes.
Excerpt from Being the Change. Get it Here.