How does a dry separating toilet work?
No water, no chemicals, no plumbing: a dry separating toilet separates urine and solids as you use it. Here is what is behind it.
By the Trenntoiletten-Check editorial team (Palo®) · updated 12 Nov 2026
The principle: separate, don’t mix
The seat contains a diverter insert. It channels urine forward into its own tank, while solids drop into a separate container at the back. This usually holds a bag, and after each use you add a handful of cover material such as coconut fibre, hemp or wood shavings.
Because the two stay apart, you hardly get the typical smell of bucket or chemical toilets. You need neither flushing water nor sanitary additives.
The parts at a glance
- Seat with lid and diverter: does the separating. How well it works also depends on the shape of the insert.
- Urine tank: emptied most often. Its size decides how long you can go without emptying.
- Solids container: usually with a bag. It needs emptying less often.
- Body: the housing, made of plastic, wood or metal.
- Optional: fan. It draws air from the solids container to the outside and needs power and a vent route.
Why it hardly smells
Odours mainly develop when urine and solids mix. If they stay separate and the solids are covered, the smell is usually low. What matters is a tightly sealing urine tank, regular emptying and a well-closing lid.
Compared with a chemical toilet
| Dry separating toilet | Cassette/chemical toilet | |
|---|---|---|
| Water | not needed | for flushing |
| Additives | cover material (e.g. coconut, hemp) | sanitary fluid |
| Disposal | urine separately, solids in a bag | cassette at a disposal point |
| Installation | free-standing, no connections | often built into the vehicle |
There are dedicated conversion kits for existing cassette compartments. They are not part of our comparison because they are installed on a different principle.