The global south is facing a major problem in managing faecal sludge, and such processes can prove to be very safe and useful
Faecal matter can be recycled and reused as fertilisers. Scientists like Josiane Nikiema from the International Water Management Institute, Ghana, say that excreta can be a rich source of nutrients for the plants.
“Decomposed excreta improves the soil structure, increases its water-holding capacity, reduces pests and diseases and neutralises soil toxins and heavy metals,” states the study done by Nikiema
However, there is a social barrier to using decomposed faecal matter, Phillimon Tlameic Odirile of Botswana University told Down To Earth (DTE). To popularise the use of decomposed faecal matter in agriculture, South Africa’s Durban city has shown the way.
In 2009, Durban’s eThekwini municipality developed the ‘LaDePa’ or Latrine Dehydration Pasteurisation machine to treat faecal sludge from the ‘Ventilated Improved Pit’ latrines. Here the sludge is extruded for the formation of pellets, which are then exposed to infrared radiation.
The final product is dried and pasteurised pellets that are safe to handle, with minimum exposure to pathogen risk. These are planned to be sold as an agricultural product.
Problem of faecal sludge
In many Sub-Sahara African countries, large amount of faecal sludge collected from on-site sanitation systems like leach pits, septic tanks, etc, are dumped in water bodies or on land. This adds to groundwater pollution, in turn affecting health of residents.
In Ethiopia, more than 250,000 children die every year from sanitation and hygiene-related diseases, Abebe Beyene from Jimma University, Ethiopia, told DTE.
Handling the excreta from pits and septic tanks, and transport it over long distances is a big challenge. Several studies have also been conducted over this issue. According to a study, published in 2018 in South African Journal of Chemical Engineering, dried pellets can be reused in agriculture as organic fertiliser.
The fertiliser has high phosphorous content, which is essential for plant growth. The study, further notes that the pellets are rich in carbon content which helps enrich the soil in organic matter.
According to Odirile, pelletisation of fertilisers also makes the process of application in the field very easy as the pellets are dust-free. He adds that the pellets release more nutrients to the soil in comparison to the traditional powdered fertilisers.
What’s stopping these pellets from becoming popular? It could be a problem of mentality, says Odirile. But he says that these pellets have been “whitened” with additional colours to promote social acceptance.
Biological analysis of the LaDePa process shows that it is very efficient in deactivating helminthes, says Mirara Simon Waweru of Egerton University, Kenya.
The global south is facing a major problem in managing faecal sludge, and such processes can prove to be very safe and useful, adds Odirile.
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