What are composting toilets?
Toilets which use little or no water and treat toilet wastes on-site for reuse as valuable compost.
How do they work?
They work by providing a enclosed environment for the natural process of aerobic decomposition. The same type of environment on forest floors which decomposes wildlife droppings and converts them into valuable nutrients for the vegetation to use.
There are many different designs of composting toilets, but all carry out this basic process of aerobic decomposition. Design variations enhance this process and they include:
• air baffles for distribution of air into the pile
• heating units to keep the compost at the best temperature
• injected air for increased decomposition
• mixing tongs to ensure full decomposition throughout the pile
• the addition of composting worms and macro-organisms
What are the advantages to the user and owner?
Greatly reduced water storage or supply costs, possibility of a rebate for community sewage charges, production of compost, in many systems the ability to compost vegetable peelings and garden trimmings with toilet wastes.
What are the advantages to the community?
If a community were to embrace the total use of composting toilets and appropriate greywater systems, it would have no sewage charges, sewage pipe installations and maintenance costs.
The community would also have greatly reduced water costs.
It could also reduce its rubbish collection charges through recycling most vegetable matter, and would be able to produce valuable compost and worm castings for sale or reuse in community and private gardens.
What are the advantages to the environment?
The widescale use of composting toilets would be very beneficial to the environment. Reduced water use would minimise storage and piping impacts, elimination of sewage would reduce nutrient flows into river and oceans and subsequent rejuvenation of marine systems.
Cities could become fertilizer factories instead of nutrient sinks, reducing environmental problems associated with manufacture of fertilisers.
How long have they been used?
Composting of “humanure” has been in existence in countries around the world for thousands of years.
The first commercially designed toilet composting systems originated in Scandinavia in the 60s. From there the idea moved to North America, where more models were designed and marketed.
In particular, Canada has become one of the leaders in manufactured composting toilet systems. The huge cottage market in Ontario has helped this trend to continue. Australia was the next to truly examine the possibilities in the 70s and they now have many systems being installed.
Composting toilets have passed the “design” phase and are now available in many countries in the world, and will increasingly expand their range as the benefits become increasingly understood.
How much do they cost?
Initial costs vary widely, but when compared to the price of a septic system installation, a composting toilet system is anywhere from 25-75% less expensive, depending on your location. For example, some new septic installations in Ontario, Canada can run in excess of C$20,000.
But, the true cost savings come in the long term, with the reduced water use costs, non-existent sewage costs, and the ability to produce valuable nutrient humus.
How do you get rid of the waste?
With composting toilets there is no “waste,” merely useable end-products.
The liquid end product has undergone conversion in the composting pile and is a valuable liquid fertilizer and/or is evaporated. Check local regulations regarding use of liquid as a fertilizer.
The solid end-product is a valuable humus with high nutrient levels in a form that is slowly released to plants on demand.
Don't They Smell?
A correctly installed and operating composting toilet will not smell at all because there is a positive suction of air through the toilet at all times. In fact, there should be less smell than a conventional toilet.
Units can produce smells if they are overloaded or not installed or operated correctly. Simple changes to the systems operation and usage will easily remedy the odour problems.
Do they clog up?
Again, they will only “clog up” if the systems are overloaded. In most cases, they will easily tolerate the shock loadings of larger gatherings than normal.
It is important to follow any guidelines suggested by the manufacturer. Most systems have rated capacities that tell you how many people can use a system.
What can you put in them?
They will compost anything organic. Basically this is anything that you could eat. But this also extends to food scraps, egg shells, paper and cardboard, lawn clippings and other small garden trimmings, clothes from natural fibres and disposable cotton diapers and tampons (without the plastic tags).
Are they approved by the health authorities?
Health authorities vary widely in their acceptance of composting toilets, usually based on their experience with them and the information that they have available to them. In most cases, once they understand the ability of composting to remove disease-causing bacterial and viruses when correct procedure is carried out, they should approve most systems where a sewage is not available. At the present, most authorities forbid their use where a sewage is available, although there are now many who are challenging this and wish to be responsible for the treatment of their own waste.