The compost heater silo can be expanded to an integrated compost heater toilet system. The system serves as a heater and a toilet at the same time. The silo is filled with waste biomass (chipped wood, etc.), which is the bases of the wet decay process. Additional biomass (feces and urine) can be added. The decay process breaks down the excreta before it can reach the bottom of the silo, so it works as a small biological clarification plant.
The combination with a toilet function provides a number of advantages:
- No water flushing system is required. This saves a lot of fresh water.
- No connection to a public sewage canal is required, because this is a standalone system.
- The resulting inorganic matter (water, CO2) does not polute the environment. The outlet water contains valuable minerals and can be directly used as liquid fertilizer for the garden.
- The additional biomass adds to the heat energy for the house warming.
- If build correctly, the slight vacuum from the ventilation pipes prevents any smell in the house, which is better than any other toilet system.
For convenience the toilet input is located on the upstairs floor, where the regular biomass inlet is combined with a toilet seat. In contrast to a dry toilet the excreta are processed in a wet environment and therefore are much faster decomposed.
In case of a poor natural ventilation the air outlet may be equipped with an additional forced ventilation device (e.g. tube fan) in order to provide enough vacuum. This device needs to be working only during the usage of the toilet. This can become necessary, if an exhaust hood is installed in the kittchen, which creates a vacuum in the house too.