Student - May 22, 2008

Great future ahead for toilet without sewer

A mobile toilet that uses almost no water was presented at a sanitation congress in Wageningen this week. It may offer prospects for slums and refugee camps, although even in these areas the water-flush toilet is on the way out.

Smells and disease are part of the image of slum areas, where people defecate in the gutter. Together with researchers from the Lettinga Associates Foundation (LeAF), the Frisian company Landustry has developed an alternative: the Mobisan. This toilet uses a minimal amount of water and does not need to be connected to a mains water supply or a sewerage system. The first trial run will be held in a slum in Cape Town later this year.

Faeces and urine are collected separately in the Mobisan. The urine is channelled away and the faeces fall into a ventilated chamber. A handle on the outside of the cabin can be turned manually to stir the solid waste regularly. This helps the excrement to dry, after which it passes into a second compartment where it is processed again in the same manner. The result is dried, pathogen-free human waste, according to Brendo Meulman of Landustrie Sneek. This can be used as manure for vegetable gardens in the slums or farms elsewhere.

The mobile toilet is an example of a new trend in developing countries, says environmental sociologist Dr Bas van Vliet, who organised the Sanitation Challenge congress together with environmental technologists. Van Vliet: ‘Large-scale attempts to introduce sewerage systems are regarded as a colonial leftover in many countries. Only a few systems have actually become operational. At the other extreme are the small-scale individual eco-toilets introduced by development organisations, but these don’t help everyone. The Mobisan is an intermediate idea, aimed at the neighbourhood level. A whole row of these toilets will be set up in Cape Town, and a district of five hundred people will be responsible for the management.’

Water-saving toilets will also become more popular in developed countries, Van Vliet predicts. ‘Many environmental technologists here at the congress are working on systems for vacuum toilets that transfer the waste to a reactor tank in a neighbourhood without wasting water.’ The traditional sewerage system where water is mixed with waste is inefficient, according to Van Vliet. ‘Unfortunately in South Africa as well, the water toilet is regarded as the Mercedes among toilets. We have to get away from this ideal.’