What is a composting toilet and how does it work?

Resource Conservation

The composting toilet combines several advantages and is ideally suited for the environmentally friendly disposal of excrements, in particular for the use in the own garden, in a mobile home, on boats and many other areas, where there is no plumbing or sewage facilities.

In contrast to the chemical toilet, where ecologically harmful substances are used to combat decay and thus the smell, using a composting toilet means the excrements are disposed of in an environmentally friendly way.

At the same time, composting can contribute to the natural cycle of the biological process.

Since water is not required for purging when using a dry toilet, one saves the precious raw material water, which is an additional advantage.

How does the composting toilet work?

The functioning of the compost toilet is simple. The excrements are collected in a container, the organic decomposition processes take their course, and the faeces can be further processed to humus by the emptying the collecting container on the compost heap.

The difference to a pit toilet is the trick with the separation of solids and liquids

It should be noted, however, that the mixing of urine and faeces causes fouling processes which lead to unpleasant odors.
Probably the best known example for this is the pit toilet, in which solid and liquid fall into a pit and remain there, often for longer periods of time, and thus the well-known sickening smell develops.
This kind of disposal is not suitable for composting, because the excrements and thus the compost would become too wet.
The simplest method of counteracting the rotting process by the mixing of urine and feces and keeping the material compostable is to cover the excretions with odor-binding and absorbent materials after each toilet run, e.g. cat litter or sawdust. Disadvantage is the frequently required emptying of the container and the fact that the compost may become too wet despite the water-binding substances.
In the classic separating toilet, the urine is collected separately from the solids.
This happens e.g. through a bowl or a funnel in the front part so that the urine can flow into a special container.
A clear advantage of this type is that the solids dry out very quickly and the composting toilet works practically odorless. Such models then have a ventilation system, which accelerates the drying out.

How does it become compost? Information for garden owners.

The dried solid precipitates and possibly residual paper residues can be safely discharged on a compost heap.

There, together with the other plant materials, they pass through the classical rotting processes over several months and finally become humus. The microorganisms and possibly pathogens from the excrements are degraded or killed in the course of time.

Compost with excrements from the composting toilet should mature for at least 1 year.

Alternatives are fast and thermo composting piles, in which temperatures of about 60-70 °C are reached inside the compost and thus the rotting and the degradation of pathogenic substances and weeds speeds up.

Conclusions on the composting toilet

  • You save fresh water
  • You do not need environmentally harmful and expensive chemicals
  • No odor
  • Compost is a valuable fertilizer