Produce water free toilet systems that rely on specially bred tiger worms to digest human waste and convert it into compost.
As long as these toilets are well maintained, the tiger worm colonies can live indefinitely within the system and may only need fully emptying and replenishing once every 10 years. The toilets use a low volume water seal to prevent any flies or gases coming back up the toilet, keeping them low odour and a specific draining layer beneath the toilet allows for the water to drain away naturally. The toilets are not well suited for wetland environments unless they are raised above the water table due to the need for good infiltration of the water into surrounding soil.
The resulting vermicompost can be accessed via a visual monitoring hatch which requires access to the surface, behind the building structure.
Wormwaster toilets require approximately double the floorspace required by a single unit mobile toilet cabin (to accommodate for the subterranean tank) however are costed at around £1000 per unit as they are quite simple structures.