Plastic pollution is one of the world’s biggest environmental problems. From deep oceans to high mountains, plastic is everywhere. It affects wildlife, damages ecosystems, and even enters human bodies.
Experts say plastic left in the environment can take up to 500 years to disappear. Yet according to the OECD, only nine percent of plastic waste in the world is recycled. The rest is dumped in landfills, rivers, and seas.
In Nairobi, Kenya, one young woman has decided to fight this problem in her own way. Nzambi Matee, a 29-year-old materials engineer, quit her job in the oil industry in 2017 to focus on recycling. She founded Gjenge Makers, a company that turns plastic waste into colorful bricks that are stronger, lighter, and cheaper than concrete.
She left a well-paid job because she could not ignore the waste problem around her. “In Nairobi, we generate about 500 metric tonnes of plastic waste every single day, and only a fraction of that is recycled,” she said. “That made me think, what happens to all this plastic?”
Her answer came through her engineering skills. She built a machine that transforms discarded plastic mixed with sand into paving bricks. By 2019, after testing many prototypes, her factory was ready for production. Today, her startup produces up to 1,500 bricks every day, recycling plastic that would otherwise pollute the environment.
At the Gjenge Makers factory in Nairobi, workers collect plastic waste from all over Kenya. The waste is washed, shredded, and sorted. Then it is mixed with sand and glass before being heated into a thick paste. The hot mixture is placed in molds and pressed under high pressure. Finally, it is cooled in a water bath until it becomes hard bricks.
The result is strong and durable. Matee explained proudly, “Because of that, it doesn’t break,” as she knocked two of the bricks together. Her bricks are waterproof, two to seven times stronger than concrete, and up to 15 percent cheaper. They also come in different colors, making them popular for gardens, driveways, and schoolyards.
Gjenge Makers is not only solving pollution but also creating jobs. The company has already recycled more than 50 tonnes of plastic and generated over 100 direct and indirect jobs. Many of these go to women and young people who collect, sort, and prepare the waste.
Sales executive John Luca is proud of what they produce. “I admire the product’s strength. It is waterproof. When we put the colour on the products, it makes a place beautiful,” he said. Operations manager Peter Kimani added, “Nzambi is an inspiration because she’s in a male-dominated field, and she’s always determined to get the job done. So, it’s a motivation to everyone who works at the company.”
Kenya’s cities are growing fast, and with growth comes the need for affordable housing and better infrastructure. Gjenge’s paving bricks are already used in schools, roads, and children’s homes. Matee wants to go further. “If a kid can go to school and arrive on time through the roads I build, I’m happy,” she said.
She is now designing new types of blocks that could be used for building houses. The plan is to create a model home to show how recycled bricks can replace traditional materials.
Not all plastics can be recycled into bricks. Out of the seven main types, Gjenge can only use four. Plastic bottles made of PET, one of the most common waste items, are still a challenge. Matee’s team is working on new technology to change that.
Another challenge is demand. The factory can produce about 3,000 pavers daily, but requests are more than three times higher. “We have more demand than we can supply,” Matee explained. To solve this, she hopes to bring in 3D technology and more automation in the future.
Matee’s work has already gained global attention. In 2021, she was invited to design a special gavel for a United Nations environment summit, where the plastic crisis was discussed. Her story has inspired many young people across Africa and beyond.
“Plastic still has value,” she said, while looking at piles of shredded plastic in her factory. “It is one of the most misunderstood materials. What we need is to rethink how we use it, and how we manage its afterlife.”
Matee wants Gjenge Makers to expand across Africa, create more jobs, and train the next generation of engineers and entrepreneurs. She believes that turning waste into useful products is the future of sustainable development.
“There is more that can be done, there is more that needs to be done. We are just a single drop in the ocean. But small drops together will make a big effect,” she said.
