How to Compost Human Waste
This article provides a general overview on how to compost human waste. It’s not much different from regular composting, but there are a few important things to know. If you follow a few simple steps, you will be able to compost human waste safely and easily, with zero odor.
Experts recommend that waste removed from a composting toilet or waterless toilet sit undisturbed in a compost bin outside for between 6 months and 2 years. However, if you live in a cooler climate, I suggest letting it sit for a full two years, just to be safe.
Adding lime dramatically reduces the amount of time the compost must sit.
Your waste should ideally be stored in a container that is not open to the bottom. You do not want anything to leach out of the container, and potentially contaminate groundwater, or be accessible to kids or animals. A compost “pile” is not acceptable.
I like the rotating plastic compost bins that are commercially available. Home Depot and local hardware stores have them for around $100-$200. It is possible to spend far more, if you choose. You could also build your own with an old plastic drum, if you are handy. The composting process is more rapid in a rotating drum. Nothing can leach out. And when it comes time to empty, it is possible with some of the drums to get a wheelbarrow under that drum for easy removal of the contents.
You need two drums, and you only use one at a time. Start using the first drum. It will take many months to fill it up, even a year or more, depending on usage and the size of the drum. When the first drum is full, add lime, and start using the second drum. When the second drum is full, the contents of the first drum should be ready for the plants.
Composting in general is not difficult, but a bit of knowledge is required. There are many websites and books that go into this in great detail. Basically the contents should be damp – not wet or dry. You might have to add a little water if it’s dry, or add some dry grass (or other dry material) if it’s too wet. Monitor your compost occasionally, and give it what it needs. You can add vegetable matter (called “greens”), dry grass clippings (called “browns”) etc., but not too much as this will reduce the capacity of the drum.
There should never be any odor. If there is, something is wrong, and you probably need to add more browns.
Flies can be attracted to any compost pile. Keep flies down with a layer of dried grass, and by ensuring the compost does not get too wet.
Many people swear by adding worms to the compost bin. I have not experimented with this.
When composting human waste, it is important to use the finished compost on non-edible plants only, and not place it directly on something you will consume. This is because there is a very small chance that dangerous bacteria or viruses are still alive in the compost. You don’t want anyone getting sick.
Making compost from the output of your urine diverting toilet is easy. However you must be careful and do everything correctly.
(Note: I am not currently recommending any specific brands of composter. Pictures are for general information only.)