An onsite sanitation technology which works on the principle of vermi-filtration, Tiger Worm Toilet (Vermin compost toilet) technology will soon be introduced in the district of Tiruchirappalli (Trichy) of Tamil Nadu. The system that rapidly converts faecal matter into vermin-compost is being introduced by the Society for Community Organisation and People’s Education (SCOPE) in collaboration with the State Government.
Director, SCOPE, Mr. M. Subburaman explained that the tiger worm toilet technology is similar to twin pit toilet technology. It will effectively work in arid areas which include 70% of Tamil Nadu as also other parts of the country that have just a moderate water table. Significantly, it is far more effective than a septic tank as it leaves a smaller footprint.
By adopting this system, Trichy is advocating appropriate technology at the appropriate place. Notably, this technology will not work in places that have a high water table such as coastal regions and river banks.
Mr. Subburaman explained how it works: “It is an ecosystem consisting of bio-media, particularly earthworms for safe, quick and efficient decomposition of human waste in pit latrines. It allows excreta to convert into vermi-compost at a very rapid rate. The treatment in the toilet technology is basically done through earthworms which are introduced into the conventional twin pit,” he said.
Procedure: To begin with, one layer of 40mm blue metal, 20mm blue metal and sand are filled at the bottom of the pit. At the time of commissioning of the toilet, 3 baskets of fresh cow dung is laid over the sand. At this point, the total height of the filter material will be about one foot. Thereafter, one kg of earthworms are released over the cow dung layer. The Tiger worm pit is now ready.
When the human waste mixed with water from the toilet enters the pit of the tiger worm toilet, the bulk of the water is leached out on all sides and through the filter materials at the bottom of the pit.
During the excavation of the toilet and the twin pits side by side, suitable cast in situ or pre-fabricated superstructures will be prepared, he added.
Similar to a twin pit toilet, this system also has two pits (each about one metre deep) with a junction chamber. Just one of the pits is used at a time and it takes about 5-7 years for it to be filled. When the pit is full the connection to the first channel in the junction box is blocked, while the channel to the second pit is opened. This can be safely and easily be done by members of the household.
In the conventional twin pit toilet, the decomposition process to make human waste into compost takes about 2 years after closing of the pit. But in the tiger worm toilet the earthworms decompose human waste in a faster manner and the waste is effectively converted into vermin-compost in about 60 days.
After a period of 60 days, the contents (faecal sludge) of the first pit form into a stable, soil-like material (Vermin compost) that can be used in kitchen gardens.
Considering that it is a passive process, there would be no energy requirements for the compact system which is less expensive to construct and operate. Also, it is a self-regulating ecosystem that stabilizes and adapts gradually to effectively handle wide variations of use.
According to the SCOPE Director, the technology has been developed in India by PriMove Infrastructure Development Consultants Pvt Ltd and Bear Valley Ventures (BVV); while the technology has been engineered and marketed by EaSol Pvt Ltd, Pune.
The technology has been so far been applied to single pit toilets. However, when the single pit is filled up, the family should be able to use the toilet. Hence, instead of a single pit, in keeping with the norms of the Swacch Bharat Mission twin pit toilet with junction box is being adopted by SCOPE.
The extra cost of the tiger worm toilet technology is only Rs 600 namely the cost of the filter materials and earth worms above the cost of a normal twin pit toilet.
Households wanting to adopt this toilet technology would require 4’x4’ space for the toilet and the super structure (the toilet building) and 10’x5’ space for the substructure (bio-digester twin pits with junction chamber just behind the toilet). In addition, accessories such as Squatting WC pan, P Trap (20 mm water seal with slope of waste disposal pipes towards pit; pipes and fittings, Fibre reinforced cement sheets (FRCS) for walls and roof, door, window, tiling for floor and wall are required. As in other toilets, storage tank and wash basins are necessary.
Mr. Subburaman also pointed out that this technology was first introduced in Cuddalore (230 kms from Trichy) by BLESS an NGO with the support of OXFAM).
Masons would have to be specifically trained for this type of toilet which would take about 3 days to complete. Unlike a bio-digester toilet where inoculum (anaerobic bacteria) is added; in this system tiger worms are used. Manure from a tiger worm toilet can be sold for Rs 10 per kilogram.
Mr. Rajesh, IAS District Collector/ Magistrate, Cuddalore has shown interest in promoting this technology under the Swachh Bharat Mission.
SCOPE is also promoting Urine Diversion Dehydration toilet (UDDT), Toilet linked bio gas plants, use of potties (for safe disposal of infant feces); use of grey water for kitchen gardening; and sludge treatment plants which are environment friendly and low cost models that require neither electricity or chemical agents.