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Swathes of water hyacinth nicknamed ‘the menace’ have suffocated the shores of Lake Victoria for over twenty years. Now a unique biogas system is primed to convert it into clean energy that will help eradicate the harmful practice of burning papyrus and firewood.

Maurice remembers when he first caught sight of the hyacinth creeping towards Dunga beach two decades ago “at first I thought it was a green flower, it looked beautiful”. But it wasn’t long before the hyacinth, a perennial water weed endemic to the Amazon basin, had enveloped the bay, blocking the landing sites and smothering the fish by deoxygenating the water and feeding off its nutrients.

To the hordes of tourists that visit Dunga beach the hyacinth creates an aesthetically pleasing effect as it hugs the shoreline, forming a floating rich green mat that glistens in the sunlight. Appearances can deceive; the weed has become a serious safety hazard for the fishermen who are caught in sudden surges of hyacinth carried in by the wind. 

The invasion of hyacinth is impacting the fisheries along Kenya’s section of Lake Victoria by suffocating the fish by sapping the water of oxygen and blocking fishing routes. According to the Kenya Fish Processors and Exporters Association in 2015 these fisheries contribute to around 2.5% of the country’s GDP. Lake Victoria, which is the source of the river Nile and the second largest freshwater lake in the world, covers an area of 68,000 km2 – almost the same size as Ireland – and is shared between Uganda (43%), Kenya (6%) and Tanzania (51%).

Scattered amongst the rocky outcrops sit dozens of stoves used by the Chiela Smart Fish women's Group. These women buy fish from the local fishermen and using firewood or papyrus to heat the stoves they fry them before selling them on. Elizabeth Achieng Keta, who is in charge of Chiela’s Smart Fish women's Group, rests behind a sliver of shade offered by a solitary snag, she explains “it’s normal for our group to experience medical issues with our lungs from breathing in smoke all day”.

The combination of the water hyacinth invasion and the reliance on the unhealthy practice of burning firewood and papyrus drew the interest of Kenyan inventor Dominic Wanjihia, who saw a solution in the form of a new mobile biogas system his company, Flexi Biogas systems had developed.

Dominic had grown frustrated by government projects that had invested millions of dollars into forklifts that aimed to remove all the hyacinth in the water, something he says is counterproductive “you take it out today and tomorrow it will be back; water hyacinth multiplies very, very fast.” So, he decided to approach the problem from another angle, “instead of trying to get rid of the menace, we thought we could try to manage it, to use it as a resource.”

His solution has come in the form of two longitudinal pre-fabricated biogas systems branded the ‘T-rex’ that now sit in a secluded corner of Dunga beach. Their unique design allows you to convert any biodegradable material, including hyacinth, into both biogases, and a ‘bio-slurry’, that can be used as fertiliser. 

Crowds gather as hyacinth is picked from the shore and fed into a shredder in preparation for feeding the T-Rex, the system quietly breaking down the nutrient-rich weed along a series of six-foot-wide modular sacks. Curiosity gets the better of a passing Boda Boda (motor-taxi) driver who disembarks from his motorbike and joins a group of locals enjoying a demonstration. Josephat Chenge, the operations manager at Flexi Biogas systems, explains “when you talk about biogas people think they can only use cow or chicken manure and therefore they disqualify themselves because they don’t have either of these”.

Flexi Biogas systems have worked with demonstrating to the fishing community at Dunga Beach that this technology, in comparison to the conventional dome shaped biogas systems, can be used with anything biodegradable. Josephat explains “In fact, cow dung produces the least amount of biogas compared to other biodegradable materials, it’s actually residual fats and food waste that produce the most.”

To explain the process of biogas production to the uninitiated, Josephat likes to compare the process to what happens in our stomach; “after we have chewed and swallowed our food, it is processed in batches and goes through three main stages before elimination. The first stage is hydrolysis, where your food gets broken down into liquids, then the acidogenesis stage, where the food turns slightly acidic and the third is acetogenesis. For humans, this is where absorption of the digested food happens” explains Josephat “but for biogas systems, there is a fourth stage called the methanogenesis, and this is where gases primarily methane and carbon dioxide are given off and are termed as biogas.”

In addition to the two commercial T-rex systems, fifty smaller domestic biogas systems have been installed in homes around Dunga beach; homes which are still covered in layers of soot from years of burning papyrus. The papyrus plant produces enormous quantities of smoke and can be found in abundance around Dunga beach.

Asthma is currently the most common respiratory illness caused by smoke inhalation but for Joanne, a member of the Chiela Smart Fish women's Group, there are two reasons why biogas could benefit her “I have chest problems because of the smoke, and I struggle with working under the sun all day” she explains “with biogas you can build a roof to solve this.” Currently, as the group use firewood to fuel the stoves, they can’t cook inside resulting in a loss of business during rainy seasons.

Dominic sees the potential impact that biogas will have on the Smart Fish women's Group as twofold; ‘Firstly, we want to demonstrate these women can get off firewood and away from smoke and secondly, we want them to be able to operate on rainy days”. The project is now receiving sponsorship from Astra Zeneca, who saw an opportunity in preventing respiratory diseases.

Collecting firewood and papyrus, a role traditionally performed by women is a labour-intensive practice. Dominic explains “some women are spending more than five hours a day collecting firewood from about the age of five to almost their grave”. By replacing firewood and papyrus with biogas, Dominic is hoping to free up their time to pursue other opportunities, something that he has succeeded in with earlier projects. 

The impact that this project could have on the community is what fuels much of his passion. For it to be successful in the long-term though he believes it has to make business sense, “we are providing a service, we don’t want to create a dependency, we are not giving it for free”. 

There are two services that the T-rex systems will provide. First gas will be pumped to local restaurants for a small charge, replacing the practice of burning firewood or papyrus. The second will be a rental of kitchenettes with stoves and multiple burners to replace the Chiela Smart Fish women's Group current setup. Workers will then, in turn, be paid to collect the hyacinth to shred and feed the T-rex systems.

For Flexi Biogas Systems the primary revenue stream will come from the fertiliser. Dominic explains that the fertiliser is valuable because of the nature of the weed “the nutrients in the water have been sucked up by the plant and turned into plant material, so we are simply digesting them and turning them back into a useful fertiliser”.

In biogas production, biomass is not converted into gas; rather biogas is a by-product of the digestion processes. As Josephat explains using his stomach analogy “In all animals including us humans, after digestion in our stomachs, the freed micro elements are then absorbed through our intestine, and the waste is passed as stool”. In a biogas digester however, the “waste” is retained until the digestion process is completed and all the micro elements have been released; Josephat continues “as the micro elements - now in dissolved form, are not removed from this process, the resultant bio-slurry is a rich organic fertiliser with a high market value”

Dunga beach is just one of many located along the shores of Lake Victoria which have been blighted by invasions of water hyacinth. Dominic hopes this setup will demonstrate to other communities the potential, “what people are calling a menace can be turned into a useful process of converting trash to cash and waste to resource”. 

For Flexi Biogas, one of the long-term goals of the project is to engage people in the business potential that an increase in time and a clean energy source can facilitate. For Dominic, this could be the catalyst for real change in the community “the more energy you have, the wider your vision becomes.”