At Dunga Beach in Kisumu, a group of innovative youth has found an unexpected solution to Lake Victoria's persistent water hyacinth problem: turning the invasive weed into cooking fuel. By combining the noxious weed with kitchen waste from local restaurants, the entrepreneurs are producing biogas that now powers fish processing operations along the beach, offering an environmentally friendly alternative to charcoal and firewood.
When Nation. Africa visited them at the beach, Geoffrey Omondi and his colleagues were sorting out waste collected from the restaurants nearby ready for biogas production.
The process begins with collection. The team distributes blue plastic buckets to local fishmongers and restaurants, gathering food waste that would otherwise end up in the lake. They carefully sort through the waste, removing plastics, glass, and other non-biodegradable materials.
Inside their facility, six large biogas digesters, protected by metal cages, convert this waste into energy. "We blend fish intestines, vegetable waste, and water hyacinth using a shredding machine to create a thick paste," Geoffrey explains.
"The paste goes into the digesters through a funnel, where bacteria break it down to produce biogas.
"We normally distribute the plastic buckets to fishmongers and restaurants around Dunga area for waste collection. This has helped in keeping the beach clean. Before this initiative, they would throw the leftovers in the lake," he says.
The team turns the mixture three times daily using attached wheels to ensure proper blending. "Without regular turning, the liquids and solids separate, affecting gas production," says Geoffrey.
The process takes three days to generate usable gas.
Geoffrey discloses that they started the biogas project in 2017 to offer consumers an alternative source of energy other than charcoal.
"Another objective was environmental conservation. We were looking for a clean source of energy which does not harm the environment," he explains.
While most biogas producers use animal waste such as cow dung, chicken and goat droppings, the Dunga beach youth have chosen to use the readily available water hyacinth, fish waste and restaurant leftovers to produce the same gas.
"Considering we are at a fishing area, it is not easy to get cow dung. That's why we settled on the hyacinth and kitchen waste as our raw materials," explains Geoffrey.
The process
Fish intestine, vegetable waste and water hyacinth are blended using a shredding machine to form a thick paste. This happens inside six huge biogas digesters caged in metal bars.
Through a funnel, the paste is channeled into the biogas digester for the process of gas formation to start.
Two wheels attached to the bio digester help to mix the paste. They turn the mixture at least three times daily.
"If we leave without turning the mixture several times, then liquids and solids will separate. The process of gas formation starts after three days," explains Geoffrey.
The bacteria present in the digester is what breaks down the waste to produce biogas. The biogas is a mixture of methane, carbon dioxide, hydrogen sulfide, water vapor and other gases.
The liquid by-product left after the production of the biogas is called a slurry. The slurry is channeled and stored into a black tank.
The liquid by-product from the digester is used as a natural fertiliser to improve crop production. They sell 20 litres of the slurry to farmers at Sh200.
They have fitted a piping system to collect the biogas from the digester. The pipes are connected to cooking appliances.
"We have fitted pipes and burners for the fishmongers to fry their fish. We charge them Sh100 per day.”
Separately, they have improvised a kiln for drying fish using a biogas burner.
The process involves cleaning the fish by removing scales, gutting and cutting the fish into pieces.
They apply oil on the racks where the fish will be placed.
Once the fish is placed on the rack, they ignite the biogas burner at the base of the kiln.
Using a valve, they control the flow of gas and adjust the heat in the kiln.
"Within three to four hours, the fish are dried. It is a clean method of preserving Tilapia, Silver Cyprinid popularly know as Omena and Lake Shrimps," said Geoffrey.
Margaret Ongoe, a fishmonger at Dunga Beach, attests that the biogas provides clean energy.
"I have used biogas for years. It is a clean source of energy and cooks faster compared to firewood, which is hazardous to human health and destroys the environment," said Ms Ongoe.