Composting Toilet

In isolated inaccessible rural areas the most sensible and safest method for disposing of human wastes is composting. If you are short on time and long on money, a reliable commercial composting toilet can be purchased or constructed. Look online for factory made units and plans. The rudiments of rot allow for two methods of composting. Anaerobic (without oxygen) compost occurs when turds are all piled up on each other with no added organic material. This is what happens in the traditional outhouse. Here the process moves slowly and often incompletely. Foul smelling compounds like hydrogen sulfide are released and little heat is generated to kill pathogens. Aerobic composting (with oxygen) works quite differently. Handfuls of organic material sawdust, grass clippings, peat, straw or leaves are added each day after use. Periodically the contents are mixed by hand or motor for several weeks. The process takes place quite quickly and few smells and a lot of heat are generated. To add piss or not to add piss is an interesting question. Urine mixed with caca will present special problems, but it can be impossible to completely separate it.   Piss is very high in nitrogen and can smother the composting process, so much additional organic matter will have to be added for successful composting if large quantities are being added to the mix. As urine is close to sterile when fresh, some simply collect it and store separately. It makes an excellent fast acting garden fertilizer when diluted 3 to 1 with water.  

A Homemade Composting Toilet

A homemade shyte composter can be easily assembled from simple materials. The container must be waterproof and leak free. It should also be kid and animal proof. A 4 to 45 gallon steel drum works nicely. (see diagram my book pg. 12) Or consider a 4’X4’X4’ wooden box lined with plastic with enough overlap to keep out the rain. This is also a good size to maximize heat retention. Top with a piece of plywood and add sawdust after each use. (see diagram my book pg. 14) It should take two people about 8 years to fill. Temperature is critical for successful composting. Organic materials do not begin to break down until the temperature reaches 18C, ands things slow down during the winter months. Paint the box black and leave it in the sun--- or even add a heating coil if you want it to process quickly. If the pile is too wet or too dry composting will be delayed. Below 40% moisture stops the process all-together, while above 70% causes the anaerobic process to take over. Somewhere in between leaves the pile damp but not sopping. 

How to Use your Composting Toilet

Remember you can never add too much sawdust, straw or leaves to your toilet and to your composter. Microorganisms need carbon for energy and growth. They also utilize a small amount of nitrogen. Thirty parts carbon to one part nitrogen is optimum for composting. Less than 20 to one and the pile starts to stink.   The Ph will be slightly acidic so add a dash of lime or ashes now and again. For speedy action the pile should be thoroughly mixed every month for the first 6 months and then every 3 months. This feeds oxygen, nitrogen and carbon to the bacteria that are doing all the work. Keep your shyte stirring tools separate from regular gardening implements. 

How long before your compost is safe to handle? Much depends on temperature. If you keep it above 18C you should have beautiful compost in 6 to 8 months. If your composter is outside and unheated, the time will be a good deal longer. Always err on the side of caution! Anyone with a serious infection like Hepatitis B, Giardia, or Cryptosporidium should be prepared to compost for several years. Never use your compost directly on food that will be eaten directly from the garden. Use instead on fruit trees and ornamentals.

But here’s a thought. When your composter fills up, simply abandon it and build another. The main thing is to keep fecal matter dry and isolated until it is thoroughly composted and safe. If you don’t feel comfortable or have the time to put extra energy into such things as turning the pile, and obsessing on temperature and moisture you really do not have to. Just mix your movement with sawdust in a watertight container and forget it. It will take longer to work out, but 15 years down the road when the box rots or rusts away it will be no danger to anyone. And using this homemade fertilizer in the orchard is not really necessary either, although it makes one feel a part of the great cycle of life and closer to the planet.