Self-contained compost toilet systems feature a commode and compost chamber as a single unit. They do not need connections to a lower floor, but do require air vent tubes and urine-diversion pipes. Self-contained systems either accumulate waste material for removal to a different location for further composting (Separett), or they actively compost to a mature stage, at which point the compost can be removed (Sun-Mar).
Please read on for further information about these systems.
The self-contained Sun-Mar system consists of a waterless, small-bin toilet that contains a composting “bio-drum” that the user periodically turns by hand. A fan moves air through the bio-drum and through the evaporation chamber.
An automatic electric heater evaporates excess liquids, resulting in a 90% reduction of the original waste. The average electrical use to run this system is 150 watts per hour. All Sun-Mar eco-toilet systems are approved in Massachusetts.
User maintenance of the self-contained Sun-Mar composting toilet system consists of:
- Rotating the drum four to six complete rotations three times a week, when in use
- Adding peat-based bulking material at the rate of one cup per person, per day.
- Rotating the drum backwards when it is one half full in order to release compost into the “finishing” drawer, where it is left to dry for 3 to 4 weeks. The compost drawer must be periodically emptied.
The self-contained Separett system consists of a waterless, urine-diverting commode over a solid waste container. A small ventilation fan (2.5 watts per hour) circulates air from the bathroom, down through the commode, and out a wall or roof vent. The Separett’s fan is also available with a 12V, 2.5 watt fan for solar/battery power. The battery can operate for about two weeks.
When the 6-gallon solid waste container is full, the user replaces it with an empty container— depending on the size of the household, about every 3 to 6 weeks. The contents can also be deposited into a batch composting system for further composting.
Urine is piped to a storage tank for periodic removal. The urine-diverting component is under review and thus the Separett is not yet approved by Massachusetts.
User maintenance of the Separett self-contained composting toilet system consists of:
- Adding a cup of wood shavings into the toilet every day (on average)
- Removing the solid waste container when full, replacing it with an empty container, and placing the solid waste container in a ventilated area to further compost for two years.
- Removing the urine from storage tank. A sensor warns the user or maintenance service when pumping is required.
More FAQs on installation and maintenance can be read here.
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