Today’s flush toilets use far less water for flushing than toilets of a generation ago. For home and property owners wanting to reduce water usage even more – or those in locations or situations where a flush toilet may not be feasible – properly installed composting toilets may be a suitable solution.
A composting toilet, according to the U.S. EPA, is “a well-ventilated container that provides the optimum environment for unsaturated, but moist, human excrement for biological and physical decomposition under sanitary, controlled aerobic conditions.” Let’s take a closer look at composting toilets by breaking down this definition into its key parts.
Composting toilets are aerobic. Septic systems, and municipal sewer systems, are usually anaerobic systems; to put it simply, that is why sewers stink. Anaerobic bacteria breaking down organic materials usually release unpleasant odors. Aerobic bacteria – oxygen-loving microorganisms – do the same job of decomposition without the stench. Just like a well-maintained compost pile will not release foul odors, composting toilets harness the power of aerobes to decompose human excreta.
Composting toilets are also unsaturated. A septic system fully immerses wastes in water. However, water limits oxygen available to the aerobic bacteria and fungi that can break down human waste and toilet paper. That is why composting toilets, by definition, do not require the amount of water as typical, flush toilets.
Composting toilets work by maintaining the right temperature and moisture conditions for decomposition. According to Texas A&M University, composting toilets maintain the right temperature and moisture by using mechanical agitators (putting to use same principle as frequently turning a compost pile in the backyard), thermostats, humidistats, heaters and fans. Installing the composting toilet properly, and following all guidelines for maintenance, helps the home or property owner to keep the toilet working properly.
A composting toilet does not require special training for operation, but it does require regular attention from the homeowner. Human excreta are rich in nitrogen, so some composting toilet systems may require the addition of carbon-containing sources to maintain the proper carbon-to-nitrogen ratio for the bacteria and fungi. The compost must be agitated and – perhaps most importantly – the finished compost (or humus) must be regularly removed and properly disposed of. Regulations mandate humus created from a composting toilet be buried (around trees, shrubs or other non-edible plants), or removed by a licensed waste hauler.
A properly maintained composting toilet can be part of the solutions for reducing water use, even eliminating the need for flush toilets in the home – especially at remote sites where water for flushing or a traditional septic system are less available. And it all depends on the principles of good composting: maintaining a well-aerated environment for oxygen-loving bacteria and fungi to create compost from organic wastes.
U.S. EPA https://www.epa.gov/sites/production/files/2015-06/documents/comp.pdf