Fermented water hyacinth fast replacing firewood for fishmongers

Eunice Anyango, a fish monger at Dunga beach in Kisumu dip fries fish at the beach on January 27, 2018. [Denish Ochieng/Standard]

For the ten years that she has been a fishmonger, Eunice Anyango has relied on firewood to fry fish for her clients at Dunga beach.

But when the Government imposed a ban on the cutting down of trees, the fishmonger’s livelihood was put at risk as her fuel of choice became scarce.

“Sometimes we face biting firewood scarcity that one piece costs up to Sh30. But most times it not even available, forcing us to go for charcoal, which is not preferred in this business,” said Ms Anyango.

The businesswoman said that on average she spends Sh1,200 on firewood every day, but the cost can rise depending on how far she travels inland to buy and transport the commodity to the beach.

And with over 30 fishmongers at the beach, at least Sh40,000 is spent on firewood, making it the most expensive raw material in the business. To make matters worse, there are the attendant health and environmental risks that come with the burning of firewood.

So it is no surprise that Anyango and her colleagues are excited about the rollout of a project that utilises water hyacinth and fish waste to produce biogas, which has long been used in homes for cooking.

When The Standard visited the project yesterday, Anyango expressed relief at being freed from the daily hassles of hunting for the pricey firewood.

“This method has no heat or smoke unlike when using firewood. Once you are connected to the source, you are good to go. We are fast embracing it and hope that soon none of us will be using firewood,” she said.

Organic nutrients

According to Dominic Kahumba, who is implementing the project, water hyacinth has organic nutrients it obtains from the polluted lake. The nutrients are rich in methane, which when extracted is a major sources of natural fuel.

Once the weeds are harvested, they are put into a shredder which chops them into small pieces. The shredded hyacinth is then mixed with water in a ratio of 1:1 before being drained into a digester.

“The shredder, apart from just chopping the material, also expels excess air from the hyacinth, given that the weed is very buoyant,” said Mr Kahumba, who is the CEO of Biogas International Ltd.

The 15-metre long digester is divided into five stages, with the first comprising hydrolysis. At this stage, micro-organisms liquefy the solid matter before it moves to the acidogenosis stage where it is made slightly acidic.

In the third stage, the acid is neutralised before the matter moves to the methogen stage where the actual gas is produced. In the final stage the gas is collected and stored before being piped to external storage facilities or channeled for use.

With two systems running, Kahumba told The Standard that they can go through 800 kilos of water hyacinth and produce nearly 20,000 litres of methane gas. That is enough gas to supply to all the fish traders at Dunga beach, and have surplus for domestic use in the neighbourhood.

Install cookers

“We are currently giving it for free to the women, but once we roll out fully we will install cookers for each of the traders at a small cost, probably less than half of what they have been paying daily for firewood,” said Kahumba.

The waste from the production of the gas, bioslurry, comes out in liquid form and can be used as animal feed or as organic manure.

Two weeks ago, former Prime Minister Raila Odinga launched a hyacinth-removal exercise from Lake Victoria, which is set to kick-off in the next three months.

According to Kenya Marine and Fisheries Research Institute, the invasive weed covered 14,000 hectares of Kenya’s water space by the end of last year.

But Kahumba said physical removal might not be the best solution to the menace because there were no proper disposal measures for the weed. The weed, he noted, had spread its seeds in the lake and would continue to grow.

“Billions have gone down the drain in an attempt to rid the lake of the weed. But if this biogas project can be embraced in the over 150 beaches along lake shore, we can achieve more environmentally, economically and socially,” he added.