Building A Composting Toilet
Overview
Composting toilets are often referred to as dry toilets and sawdust toilets. They’re becoming much more popular as time goes on because they do not waste clean drinking water to flush down toilet refuse. There are many different composting toilet designs, and several are quite easy to make yourself. The two simplest are the bucket system and the bin system.
Bucket System
A composting toilet bucket system uses 5 gallon buckets as the actual toilet bowl container. As the current bucket becomes full, it is removed from the toilet box and taken to an outside compost pile for emptying.
To build a composting toilet which uses buckets, you’ll need some basic tools, wood, buckets and a toilet seat.
Using plywood, build a box which measures 10 inches deep, 18 inches wide and 21 inches long. Attach 12 inch tall boards in each corner to create legs, and attach an 18 inch by 18 inch plywood to the top with hinges at the back. This hinged setup will allow you to open the top of the toilet for easy bucket removal.
The top piece of plywood needs to have a hole cut into it that fits your bucket. Lay the bucket upside down on the plywood and trace around the opening for your cutting template.
Once the top hole is cut you can then attach a regular toilet seat on top. The bucket goes inside your box and the toilet seat and hole fit down tightly onto the bucket to make a seal.
Bin System
Not everyone likes the idea of emptying a composting toilet bucket regularly, thus the bin system is a popular variation. With it, your toilet box is built directly on top of your compost bin.
Your compost bin can be as large or small as you’d like it, but the best results come from building a double bin that’s 4 feet tall, 5 feet wide, and 10 feet long. This double bin will be separated in the middle so that you have two 5 feet by 5 feet compost bins.
These compost bins can be built anyway you’d like, and the simplest is to use scrap wood or pallets put together in basic box form. There doesn’t need to be any floor or bottom to the bins, just the sides. You’ll also want to add a gate or access door area at the back of each side to make it easy to remove the compost once it’s finished.
A double bin system like this generally has the bathroom built on top of the compost bins, and a standard box style toilet like the one described above. Instead of having a bucket in the box however, you’ll have a direct opening to the compost bin below.
This type of composting toilet is used on one side for a year, then the toilet box is moved to the other side for the second year while the first year compost rests and finishes fully decomposing.
References: The Humanure Handbook Third Edition; Joseph Jenkins; 2005
