How to build a composting waterless toilet

A composting toilet is a waterless toilet consisting of two or more 5-gallon buckets, sawdust or other organic material (lime or wood chips), and a toilet seat.

Since it does not use water, it saves clean water, a limited resource.

Composting and fertilization are important steps to organic farming and gardens. In order to get the level of nitrogen needed, you may use a waterless toilet and add the product to your compost pile.

Humanure provides valuable source of nutrients needed for compost. It contains high levels of nitrogen and is easily collected using a waterless toilet.

The compost - also called humus, is an organic fertilizer which replenishes and improves the quality of soil. This type of fertilization is useful in areas where there is no money to spend on expensive fertilizers and pesticides. Organic farms or gardens can use this too in order to have a healthy growth of plants.

Methods

The main problem with a composting toilet is the odors and pathogens associated with it. In order to keep the odor under control, it is important to apply a covering of sawdust or other high-carbon material whenever the waterless toilet is used. This will help reduce the odor and also keep the waterless toilet and compost pile hygienic. Another method that should be used in conjunction with the high-carbon material is ventilation. This can be as simple as a gap between the wall and the roof or more complex like an electrical ventilation fan.

Social context

In America people are less likely to use this method of conservation because of their extraordinarily high standard of living. This would be very useful in many parts of America, especially in the areas where there is seasonal water shortage. Droughts would not affect the area as much if everyone used this type of toilet because of the water saved from using the waterless toilet.

There are many examples of waterless toilets being used around the world. The C.K. Choi Building at the University of British Columbia contains ten composting toilets which are used for 300 full time employees. Also the IslandWood School on Bainbridge Island in Washington relies soley on composting toilets. Although the composting toilets that are used in these buildings are not as simple as the waterless toilet that is explained in this article, they are useful and more sanitary for the large number of people who use them.

The method explained in this article is more likely to work in less developed countries. Some places are currently using latrines and other methods of waterless toilets, so they would gain from their wastes being used as compost material and enriching their soil.

Composting process

Depending on your location, the composting process can take from three months to a few years depending on climate, temperature and composting system. There are two ways to kill the pathogens in the waste. One method is to allow the waste to be a low-temperature where it is left long enough for the pathogens to break down naturally. There are also hot, thermophilic toilets which heat the waste to a temperature high enough to kill the pathogens.

In order to preserve the majority of nitrogen (90%) and phosphorus (70%) it is important to preserve the urine. An advantage to this method of composting toilet is that it saves these valuable nutrients for reuse instead of allowing them to leach into the groundwater.

Steps to build a waterless sawdust toilet

A simple version of the composting toilet is the waterless sawdust toilet. This utilizes three or more 5-gallon buckets. One holds sawdust (to be used to cover wastes) and the other has a toilet seat fitted to it for use as the waste receptacle. The others are used as "back up". One way to secure the seat is to fit it to the top of the seat. The materials needed are: three or more plastic 5-gallon buckets, one toilet seat, 6 wood screws, and 3 small pieces of wood that function as cleats (approximately, 1 inch wide by 3 inches long by 3/4 inch deep). You will also need a compost chamber, which can be easily constructed from wooden pallets and wires. The only tools needed are saws and screwdrivers.

Anyone can build their own waterless toilet with slight instruction. It costs only about $15.00 to construct and is aesthetic and hygienic.

These are the steps to build your own waterless composting toilet:

1. Using a wood saw, cut the top 4 to 6 inches off one of the buckets. This will serve as a flange to which a toilet seat is attached, allowing it to slip inside a second bucket. (Photo 1)

2. Attach this flange to the bottom of a toilet seat using two screws at each of three wood cleats. One screw attaches the cleat to the toilet seat; the second attaches the bucket flange to the cleat. (Photo 2) The four small brown objects in the photo, the original toilet seat spacers, are removed and discarded. The completed receptacle with flanged seat in place on a receptacle bucket is shown in Photo 3.

3. A second bucket contains sawdust, chipped wood, chopped straw, cereal hulls, or other absorbent carbon-rich organic matter. Covering with several cups or handfuls of this matter after each use effectively prevents odors.

4. When the receptacle bucket is full, transfer the flanged toilet seat to the now empty sawdust bucket which then becomes the receptacle.

5. Now empty the receptacle bucket. After emptying, sanitize the bucket. After sanitizing, this bucket will become the sawdust container and the old sawdust container will be the new receptacle. The cycle then continues...

Photo 1:

Photo 2:

Photo 3:

References

• "How to Make and Use a Simple Sawdust Toilet," 2005. Available: http://ersson.sustainabilitylane.com/sawdust.htm

• Composting Toilet World "An Introduction," 2007. Available: http://compostingtoilet.org/compost_toilets_explained/what_is_a_composting_toilet/index.php

• The original fully editable article on Appropedia includes content from an original (more detailed) document (Appropedia:Recycling agricultural wastes to produce hot water (original))