Composting Toilets in a Cozy Home
Some builders who are building a Cozy Home may be building in an area without a local sewage line or even a septic tank. Some may also want to avoid using water to flush their toilets in regard to the environment or in order to save water if its scarce in their area. Installing a composting toilet will fulfill all of these home building desires.
There are various types of composting toilets on the market these days and some are even designed to fit into small or tiny homes. The process of a composting toilet is essentially the same, but different toilets will compost material in different ways. Composting toilets use aerobic processing to treat excrement. This process is sometimes helped along by dumping small amounts of sawdust, coconut coir or peat moss into the bowl to help with anaerobic decomposition. During the decomposition bacteria that thrive at high temperatures (40-60 °C or 104-140 °F) oxidize (break down) the waste into its components, some of which are consumed in the process, reducing volume, and eliminating potential pathogens.
There are several different types of manufactured composting toilets:
The types of composting toilets complete or begin the composting process in a container within the receiving bowl. They are slightly larger than a flush toilet, but use roughly the same floor space. Some units use fans for aeration, and optionally, heating elements to maintain optimum temperatures to hasten the composting process and to evaporate urine and other moisture. Operators of composting toilets commonly add a small amount of absorbent carbon material (such as untreated sawdust, coconut coir, peat moss) after each use to create air pockets for better aerobic processing, to absorb liquid, and to create an odor barrier. This additive is sometimes referred to as “bulking agent.” Some owner-operators use microbial “starter” cultures to ensure composting bacteria are in the process, although this is not critical.
Remote, central, or underfloor toilets
These types of toilets collect excrement via a toilet stool, either waterless or micro-flush, from which it drains to a composter. “Vacuum-flush systems” can flush horizontally or upward with a small amount of water to the composter; “micro-flush toilets” use about 500 millilitres (17 US fl oz) per use. These units feature a chamber below the toilet stool (such as in a basement or outside) where composting takes place and are suitable for high-volume and year-round applications as well as to serve multiple toilet stools.
These types of toilets dry the excreta to destroy pathogens, though one study suggested that drying can result in rehydration of pathogens when in contact with moisture later.
Prices of composting toilets can range from about $500 to over $2,500 depending on the brand and the type. The Sun-Mar Spacesaver Self-contained Composting Toilet is around $1,600 and is made to fit in a home with limited space. It’s only 19.5 inches wide and uses a patented Bio-drum which ensures fast and odorless decomposition.
Top photo from Mother Earth News