Over the past couple of weeks, we have had two new researchers in the biology department who are working on a new project looking at worm-based sanitation for developing countries. These are not compost toilets, they are have a flush mechanism, but they will use much less water than conventional toilets.
The purpose of the project is to design non-piped sanitation systems that don’t fill up quickly – which is a problem with the conventional pit latrines used by millions of people in developing countries. Biofilters are contained units typically consisting of an active layer near the surface, where worms (often tiger worms) and other organisms digest the solid waste as it enters the system. Beneath this is a filtration bed where the liquid waste is further treated by aerobic bacteria, resulting in a highly treated effluent which can be safely discharged into the environment. The unit can be linked to flush or pour-flush toilets, so there’s the immediate benefit of waste being removed from sight, compared with a latrine.
Research shows that worms such as tiger worms eat human poo, but experiments have to be carried out to work out exactly how much they can consume.
The first set of experiments will therefore look at how many worms would be needed for these new types of toilets.
The second phase of the project will be to design and test these new toilets. We should have a small prototype at CAT in a few months and will keep you updated on the findings following this project.
This worm-centred approach is just one of several being explored by Sanitation Ventures ,a larger project at the London School of Hygiene and Tropical Medicine, funded by the Bill & Melinda Gates Foundation working to find solutions to the problem of pit latrine filling. More information can be found here.