In Summary
  • Scientists have created a simple method of recycling human waste into animal feed and fertiliser — using a fly.
  • The researchers collect the waste from the school, where they have constructed special toilets that separates urine from stool, and take it to the research centre at the university, where it is transformed into animal feed and organic fertiliser.

Researchers at Meru University of Science and Technology (MUST) have invented what is billed as a solution to the problem of poor sanitation in congested urban and rural areas. It is also expected to contribute to efforts to attain food security.

The scientists have created a simple method of recycling human waste into animal feed and fertiliser — using a fly. The project, dubbed Bio Resource Based Sanitation, is already in the piloting stage at Kunene Primary School, just opposite the university in Nchiru, Tigania West Sub-County.

The university is undertaking the project in collaboration with Aston University in the United Kingdom under the Newton Utafiti Fund, which builds research and innovation partnerships.

Trials started in September last year with a modest funding of about Sh4 million, with the project bringing together four departments at the university — Microbiology, Mechanical, Civil Engineering and Business.

THE PROCESS

The researchers collect the waste from the school, where they have constructed special toilets that separates urine from stool, and take it to the research centre at the university, where it is transformed into animal feed and organic fertiliser.

Listening to Joy Irungu, the lead researcher who is the brain behind the project, explain the process, one wonders why sanitation should remain a problem after commercialisation of this invention. Her colleagues from the other departments are Dominic Kiogora, Dr Guyo Huka, John Njeru and Sarah Wandili.

But Ms Irungu, a civil engineering lecturer, first explains how they breed the black soldier fly, the main agent of her invention. “We enclose the flies [in] a net, where they lay eggs which hatch into larvae. Before they get to pupae stage, they need to eat a lot and this is when we introduce them to the waste,” she says.

The scientist says as the larvae feed on human, kitchen waste or even cow dung, they grow into pupae ready to become grown flies. After consuming the waste, what remains is a black substance.

Ms Joy Irungu (left) shows larvae at the research centre during the launch of the project. PHOTO | GITONGA MARETE

Ms Joy Irungu (left) shows larvae at the research centre during the launch of the project. PHOTO | GITONGA MARETE

This process takes about 10 days and at the optimum larvae stage, the scientists kill the insects by dipping them into hot water. They then dry and mill them into powder to produce animal or fish feed concentrate rich in proteins that is mixed with other feeds.

Before the product is packaged, it is taken through testing at the laboratory to ensure it is fit for animal consumption. The dried larvae may also be fed to chicken just like they eat them from decaying matter when they free-range. Some larvae are allowed to grow into flies, completing the cycle.

“The larvae contain high levels of protein at 60 per cent even more than omena (40 per cent), and when it is added to other types of feeds, it is very nutritious. The black substance is organic fertiliser which is a good soil conditioner,” says Ms Irungu, adding that urine is also used to make another type of fertiliser.

She says her invention was inspired by health challenges resulting from poor sanitation, which is a major cause of waterborne diseases. She conceived the idea while studying for her PhD. She developed an interest in effective sanitation technologies for informal and peri-urban settlements.

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