Vermifilter toilet


Vermifilter toilet, also known as a Vermicomposting toilet, Vermidigester toilet or Tiger worm toilet, is a type of pour flush composting toilet that uses worms as a vermifilter to decompose human excreta.

Description

Vermifilter toilets contain composting worms that digest faeces, thus reducing the accumulation rate, and significantly extending the frequency intervals for the removal of the solid waste. A worm colony can live inside the toilet indefinitely as long as the correct environmental conditions are maintained. In long-term refugee camps, this reduces the need to replace filled pit latrines, and is a more cost-effective solution. Flushing water is required to dilute the ammonia produced from urine, a ventilated aerobic environment must be provided, and the flush water must be able to drain away.
Every 8 to 10 years, maintenance on the toilet must be performed, which consists of removing the accumulated worm castings. The worm castings are suitable as a soil conditioner, and may be used as fertilizer. A typical pit latrine may need to be completely emptied or rebuilt after 2-3 years and often comes with smell and contamination issues. A primary vermifilter provides primary treatment of the liquid effluent generated by humans and worms and decomposes the solids into humus. The filtered waste is not a safe or sanitized material and is normally disposed of in an underground soakage trench or "soakaway".

Examples

Anna Edley constructed a vermicomposting flush toilet in 1995, called the Solviva Biocarbon filter system. Colin Bell from New Zealand began marketing his "wormorator" in the early 2000s, which was a twin-chamber vermifilter toilet. Colin provided information on the construction of his "wormorator" to Claire Furlong of the London School of Hygiene and Tropical Medicine, who had secured grant money from the Bill & Melinda Gates Foundation to develop and field test the technology.