jqmello: This is from the website of the toilet.
"Capacity - How often should the toilet be emptied?
If four people are using the toilet on a daily basis, then a container will last about 3-6 weeks, depending on how much toilet paper is being used. For a normal summerhouse, 2-3 containers will suffice. The Separett Villa comes with three containers. Additional containers can be purchased if required.
How is it possible that the container with solids so rarely has to be emptied?
Urine accounts for about 85% of the waste volume and is routed separately away from the toilet. This increases the storage capacity for solids greatly. The container is easily replaceable and if the amount of users increases one only change containers more often. The Separett Villa comes with three containers. Additional containers can be purchased if required giving the toilet virtually unlimited capacity.
Are there unpleasant odors indoors?
No. If the fan runs continuously the there will be no unpleasant odors in the room. When installing the toilet, make sure that the venting pipe is properly sealed with silicone. The easily accessible fan filter should be cleaned regularly as well as the insect net at the end of ventilation pipe. "
It's actually why I picked this particular one. So with my 8 people I should need to empty it every 1.2-3 weeks. Totally worth not dealing with a black water tank. The reviews I've found seem to hold up the claim. If anyone has any personal experience though I would love to hear some.