Self-sustaining toilets for Indian slums

A self-sustaining toilet capable of running without any external water for years in Indian slums is under development at a Swiss laboratory.

The researchers hope to put the toilet under test by 2017-18 in India once they find out ways to overcome two key psycho-social barriers for the users. Preliminary ground tests at Kampala and Nairobi, however, did not bring out those challenges that will surely come up in conservative Indian society.

Being developed with $2 million funding support from the Bill Gates Foundation, the toilet contains 60 litres of water, which is recycled using sophisticated “membrane filtration” technology to perpetually generate safe, hand-wash quality waters for ten users a day. As the toilet is equipped with a small pump for pushing up the water to the storage tank for hand wash and a tiny fan for removing the bad odour, solar panels are fitted on the top for electricity needs.

The researchers have also developed a parallel technology to generate nitrogen fertiliser from the urine.

A 20-member team at Eawag, Switzerland’s premiere institute of aquatic research, created two prototypes at a cost of 12,000 Swiss rranc (about $ 12,400) apiece. Both were tested successfully in the two African cities in the last two years. “For India, overcoming the cultural barriers is more important,” Christoph Luthi, a senior scientist associated with the Eawag division on water and sanitation in developing countries, told a group of visiting Indian journalists.

There are two problems – the first one is the mental block in washing the hands in water that comes out after recycling the urine and secondly relieving in the same pit, knowing fully well the presence of somebody else’s poop below. “Because of these factors, we are not projecting it as a public toilet, but as a toilet for a small family living in the slum. Also we aim to bring down the cost to $150-200,” he said.

Asked how the users in Kampala overcame the second bottleneck, Luthi said the users put newspaper pieces inside the pit after every use. Since an NGO was involved in cleaning the prototype toilets twice in a week to remove the faeces, it was not a problem.