5.11 Examples from India and Bangladesh

Vermifiltration in India

NGOs, government organisations, and private sectors offered their assistance to the Kerala government. As a part of the rehabilitation program, a vermifiltration plant capable of treating 10m³/d of faecal sludge was installed in Kalpetta Town, Kerala.

The vermifiltration process uses a species of earthworms known as tiger worms to treat faecal sludge after anaerobic digestion. The treatment process involves two vermifilters in sequence. The first vermifilter receives sludge from the digesters and traps the organic matter on top of the filter, which is processed by worms and bacteria. The liquid then passes through the filter and is further processed by the second vermifilter to reduce the organic load further. Subsequently, the effluent is treated by a sequence of rapid sand and an active carbon filter before it is disinfected.

Tiger-Worm Toilets in Bangladesh

Tiger Worm Toilets (TWTs), sometimes known as Tiger Toilets or vermifilter toilets, contain composting worms inside the pit that process and digest the faeces in-situ, replacing the build-up of raw sludge with vermicompost. This removes the need for traditional desludging, as the vermicompost is simpler to remove and builds up at a slower rate. This can lead to a reduction of the long-term operating costs and removes the need for expensive desludging and sludge treatment infrastructure. A worm colony can live inside the toilet indefinitely, so long as the correct environmental conditions are maintained.

Biofilcom is one of the companies providing TWTs as the so-called Biofil toilet in Bangladesh.

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