Lake Naivasha, northwest of Nairobi, Kenya is becoming increasingly unnavigable. Water hyacinth, the world’s most widespread invasive species, is blanketing the lake, choking its fish and leaving people stranded.
“Sometimes it becomes very serious,” says Simon Macharia, a local fisherman, about the weed problem. “There was this incident where fishermen were trapped by hyacinth inside the lake for three days. We had to seek help from the government (who) used a helicopter to rescue them.”
Macharia says that some days he’s simply unable to fish on the lake because of the plant. When he does, he can lose his nets underneath the floating weed, incurring costs while preventing him from earning that day. Water hyacinths also cover the surface, cutting off sunlight, outcompeting other plant species and starving water of oxygen. That means there are fewer fish for Macharia to catch in the first place.
The problem is so vast it can be seen from space. It also threatens the cut off the flower industry in the wetlands surrounding the 150 square kilometer (58 square mile) lake.
What’s happening in Lake Naivasha is a story repeated all over the world. Water hyacinths are native to South America, but were introduced as an exotic ornamental to many other countries. They’ve since taken over freshwater environments and are labeled an alien invasive species on every other continent aside from Antarctica.
As well as their impact on biodiversity and livelihoods, the floating plant can clog hydroelectric and irrigation systems, meaning that one does not need to live in their proximity to be affected. It’s the highest-profile example of an invasive aquatic plant crisis that has cost the global economy tens of billions of dollars historically, and now more than $700 million annually.
The problem with water hyacinths is particularly acute in Africa. A 2024 report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), a body founded by the UN Environment Programme, described the plant’s “exponential expansion,” with land use changes and climate change adding potential fuel to the fire.
Taskforces from multiple organizations have attempted to find solutions. Introducing weevils that attack the plant can restrict its spread and even cause it to lose buoyancy. There are also proposals to harvest the water hyacinth and combine it with municipal waste and cow dung to produce biofuel. Now a Kenyan company is addressing the problem as well as the country’s plastic pollution issue by turning the invasive plant into a bioplastic.
HyaPak Ecotech Limited, founded by Joseph Nguthiru, began life as a final year project by the former Egerton University civil and environmental engineering student. Nguthiru and his classmates experienced the problem of water hyacinths firsthand on a field trip to Lake Naivasha in 2021, when their boat became trapped for five hours. They returned determined to do something about it.
Nguthiru’s bioplastic is made from dried water hyacinth combined with binders and additives, which is then mixed and shaped.
The product, which biodegrades over a few months, was first used as an alternative for plastic packaging. In 2017, Kenya introduced a law banning single-use plastic bags, and in 2020 all single-use plastics were banned from protected areas. The results have been mixed; with homegrown manufacturing banned, there have been reports that single-use plastic bags have been smuggled into Kenya from neighboring countries. “The problem behind (the ban) is that there were no proper alternatives that were produced,” argued Nguthiru.
His product is “killing two birds with one stone,” he believes. “Most single-use plastic products tend to have a lifespan of about 10 minutes after they come out of supermarket shelves. So why not make them biodegradable?”
HyaPak has gained widespread attention, winning the Youth category at the East Africa Climate Action Awards, a prize at UNESCO’s World Engineering Day Hackathon, and a Prototype for Humanity Award 2023 announced at the COP28 climate conference. Nguthiru was also named a 2023 Obama Foundation Africa Leader.
Fishermen including Macharia are now harvesting the invasive plant on Lake Naivasha, then drying and selling it to HyaPak. It’s a useful alternative income, he said, especially on days when the plant has covered his net, preventing it from catching fish.
Macharia said he hopes HyaPak will soon be able to scale up its activities, allowing the lake’s surrounding community to harvest greater quantities of water hyacinth. “If Joseph could get funding, I think he can buy larger quantities and at least many people will get work,” he said.
One project that could help HyaPak grow is its partnership with the Kenyan government to use its products as part of a flagship reforestation scheme.
According to Global Forest Watch, Kenya lost 14% of its tree cover between 2001 and 2023. In late 2022, Kenya’s Forestry and Land Restoration Acceleration program committed to planting 15 billion seedlings by 2032 on degraded forest and rangeland. Doing so would bring the nation’s tree coverage to over 30 percent, said the government.
All those seedlings need bags in which to grow and be transported, and HyaPak’s seedling bags are part of the plan, said Nguthiru.
A plastic-based seedling bag has a carbon footprint of 1.6-1.7 kilograms, according to Nguthiru, and it is disposed of when the seedling is planted. HyaPak’s alternative is planted with the seedling and biodegrades, releasing nutrients including nitrogen. What’s more, during the seedling’s first months, the bioplastic slows water seeping into the surrounding soil, reducing the amount of watering required.
“You offset the carbon emissions that are going to be produced, you’ve used less water, you’ve added more nutrients … it’s a win-win situation for communities, for the planet and for yourself as a farmer,” Nguthiru argued.
HyaPak is already exporting to the US and Germany and plans to establish franchises in India and El Salvador – two countries with freshwater blighted by water hyacinth.
Nguthiru wants to create the quickest route for the world to benefit from his innovation, “Even if that means open-sourcing some of this, so that the product and development and advancement of biodegradable plastic can go really fast, so be it.”
Beyond water hyacinth, he thinks urgent action is needed to tackle the climate crisis: “Previous generations have failed us, and the ones that are coming afterwards are looking up to us. We are the ones who are going to live with a planet that’s beyond 1.5 degrees Celsius (global temperature rise),” he said.
“It’s up to my generation to come up with solutions for the climate crisis, because if we don’t do it, we are not going to do it at all.”