Human waste can be one of the most dangerous sources of contamination on any homestead, or municipal. It has many pathogens, beyond those in most animal manures, that should be destroyed, not allowed to breed in a nice, cozy, wet tank underground.
With a compost toilet, you know exactly where things go. You can monitor the system, make changes if needed, and enjoy the responsibility of disposing of your waste properly. No septic system owner can say the same.
Humanure also makes excellent compost and is a great water saver. Flushing that toilet wastes an enormous amount of good drinking water (over 50 gallons per person per day in the USA). If you are interested in this subject, a must-read book is Humanure by Joseph Jenkins.
Decide upon the design of your toilet and what you want/need before you start.
We built a container for sawdust and a two-bay toilet, so that one day we will be able to separate our feces and urine. Urine has its own use beyond composting. For example, it is great for trees, especially if you pee on bio-char, which absorbs the nutrients and releases them slowly. For the time being, however, while our kids are young, we have one adult toilet and one with an infant seat.
We also built arm rests into the unit. We figured that these would help the kids when getting up and are also invaluable in the case of injury, to be able to lower yourself down onto the seat.
We chose to build our toilet out of 2″ x 2″ lumber and 1/2″ plywood. We then painted it all to protect it and make it easier to clean.
You can use wood, metal or even concrete.
You’ll also need a bucket or container and a toilet seat.
When we were designing our bathroom, we incorporated a solar air vent that went from the inside of the composting toilet unit to the outside. The toilet doesn’t really need it, so don’t worry if you don’t want to do one. But it was so easy to do as we were building that we thought why not.
The black pipe will heat up in the sun, causing the air to rise. As it rises, especially as it is so tall, it will create a pull on the air inside the toilet unit. When the sun is shining, you can place your hand over the pipe inside the toilet unit and feel the pull.
After each use of the toilet, you’ll need to sprinkle a cover material, like sawdust or peat moss, into the bucket. Personally, we prefer sawdust. We find it takes away the smell more effectively, and is readily available to us.
The cover material helps absorb moisture, and adds to the decomposing process by balancing carbon material to your nitrogen. It therefore helps to have a container near your toilet to hold the cover material.
Once the bucket gets filled up, you’ll need to empty it into a compost bin. The pile method is great for almost all of your other organic waste, and especially all of the organic matter from the garden, but we do not recommend it for composting humanure. For that, it is best to use a separate bin, and let it sit longer, just to make sure it gets broken down and also to give the bacteria ample time to eat any bad stuff that might be in there, like worm eggs, parasites, or harmful pathogens.
The bin that we use for humanure works great and is easy to build. We have three of them. By the time the last is filled, the first is fully composted and can be emptied wherever you need the soil enriched.