Gardening is not for the squeamish. Never mind the sow bugs, wireworms and slugs, the entire process involves developing an obsession with dirt. Regular readers of this column will understand that nutrient rich soil is critical to raising a good crop, and how important horses, cows and chickens can be to the production of good compost. There are a growing number of agriculturalists who believe that we should not be relying simply on animals to do all the work for us. If we want something done right we should do it ourselves.
In The Humanure Handbook, author Joe Jenkins poses an awkward question: “Why do we defecate into clean drinking water?” Jenkins points out that ever since Thomas Crapper invented the flush toilet, we have considered human manure a waste to get rid of instead of the resource it once was. If we look beyond the “yuck” factor to acknowledge the presence of minerals and enzymes we excrete, we realize that we are flushing away these assets. That is why Mr. Jenkins designed a composting toilet that he’s been using to fertilize his family’s vegetable garden for decades.
We know our soils lose valuable minerals when we grow crops, and once we have extracted the nutrition by simple digestion there is an inescapable logic to the argument that it makes good economic and environmental sense to recycle the remaining minerals rather than simply flushing them away with our precious drinking water. Jenkins argues that we need to overcome our squeamishness and make use of a currently wasted resource.
Some societies already understand the value of humanure in the food cycle. Sir Albert Howard, who developed the present day method of composting, reported that in Pakistan the Hunza people have been doing it for centuries. “The very greatest care is taken to return to the soil all human, animal and vegetable (refuse) after first being composted together.” He reports that the Hunzakuts enjoy better health than their more wasteful neighbours.
The secret to creating a useful product from our humanure, Jenkins concludes, is to compost it first, beginning with the toilet and continuing the process in the compost heap outside. When the mixture is added to carbon rich vegetation and made into a pile, aerobic organisms break it down to produce pathogen free compost. Jenkins provides his own garden as proof. He has tested his compost heap and found that it exceeded both the temperature and length of time required to kill off all pathogens. Indeed, in the 30-plus years he’s been composting his family and various visitors’ manure, no one has ever contracted any disease or worms from their produce.
Plans abound for making composting toilets, but I like Jenkins’s model for its simplicity, elegance and adaptability. He uses two plastic buckets, one for immediate use and the other on standby. He pours in about four inches of any dry shredded material that will absorb well, like coir, sawdust, peat or shredded leaves. Jenkins built a frame to house both buckets and a receptacle for additional coir. A regular toilet seat sits on the frame above one of the buckets, and after each use Jenkins scoops out some coir from the receptacle and pours it on his creation. When it’s full, Jenkins carries the bucket out to a compost heap, pours it onto the middle and covers that with straw that he keeps under cover outside. He also puts all vegetable scraps onto the same heap.
Given our continued decrease in fresh water supplies, perhaps we should start looking at ways to treat our effluent other than defecating into it. Already southern Californians are drinking water that has been used and reprocessed 150 times before it leaves the Colorado River and heads for Los Angeles.
Perhaps our expensive new sewer systems wouldn’t be necessary if we were using composting toilets instead of just pulling the handle. Now I shall close with one of those historical anecdotes David is so fond of.
In ancient Rome the public urinals used to recycle their fluids by providing them free of charge to the tanneries, until the Emperor Marcus Aurelius decided to charge a fee for the service. When his son Commodus complained about the source of this new income his father held up a coin and asked if it smelled any different.
Waste not, want not.