Building blocks for a greener Nairobi

Nzambi Matee’s small workshop in Nairobi, Kenya is chock-a-block with metal pipes and machine cogs.

It may seem chaotic to outsiders but the 29-year-old Matee, an inventor and entrepreneur, is at home here. This is where she developed the prototype for a machine that turns discarded plastic into paving stones – an invention that underpins her company, Gjenge Makers.

Each day, the business churns out 1,500 plastic pavers, which are prized by schools and homeowners because they are both durable and affordable. Gjenge Makers is also giving a second life to plastic bottles and other containers which would otherwise end up in landfills or, worse, on Nairobi’s streets.

“It is absurd that we still have this problem of providing decent shelter – a basic human need,” said Matee. “Plastic is a material that is misused and misunderstood. The potential is enormous, but its after life can be disastrous.”

Gjenge pavers are fully certified by the Kenyan Bureau of Standards. They have a melting point over 350°C, and they are much stronger than their concrete equivalents.

For her work, Matee was recently named a Young Champion of the Earth by the United Nations Environment Programme (UNEP). The award provides seed funding and mentorship to promising environmentalists as they tackle the world's most pressing challenges.

“We must rethink how we manufacture industrial products and deal with them at the end of their useful life,” said Soraya Smaoun, who specializes in industrial production techniques with UNEP.  “Nzambi Matee’s innovation in the construction sector highlights the economic and environmental opportunities when we move from a linear economy, where products, once used, are discarded, to a circular one, where products and materials continue in the system for as long as possible.” 

The heavy toll of plastic

The world is awash in plastic. Globally, 1 million plastic drinking bottles are purchased every minute while up to 5 trillion single-use plastic bags are used annually.

Matee, who majored in material science and worked as an engineer in Kenya’s oil industry, was inspired to launch her business after routinely coming across plastic bags strewn along Nairobi’s streets.

In 2017, Matee quit her job as a data analyst and set up a small lab in her mother’s back yard. There, she began creating and testing pavers, which are a combination of plastic and sand. The neighbours complained about the noisy machine she was using, so Matee pleaded for one year’s grace to develop the right ratios for her paving bricks.

“I shut down my social life for a year, and put all my savings into this,” she said. “My friends were worried.”

Through trial and error, she and her team learned that some plastics bind together better than others. Her project was given a boost when Matee won a scholarship to attend a social entrepreneurship training programme in the United States of America. With her paver samples packed in her luggage, she used the material labs in the University of Colorado Boulder to further test and refine the ratios of sand to plastic.

Matee also used this opportunity to develop the machinery she would use to make the bricks. “Once we know how to make one paver, we need to know how to make 1,000 pavers,” she explained.

Reaching the finish line

Matee recalls the first time she produced a full batch of recycled plastic pavers. “It was the best day ever!” she exclaimed. “This was three years of hard work. I quit my job. I put all my savings into this. I became so broke that everyone thought I was crazy and so many people told me to give up.”

One of the schools that uses pavers is the Mukuru Skills Training Centre in Nairobi’s Mukuru Kyaba slum. Its playground and the paths between classrooms are covered by Matee’s colourful paving stones. (Before the pavers, students walked on dirt paths.)

“We plan to pave all around the school,” said programme coordinator Anne Muthoni. “It’s a cheaper solution and we are grateful to Nzambi. Young people need to be motivated and sensitized about how to care for the environment, while at the same time making money.”

Matee encourages other young people to tackle environmental challenges at the local level. “The negative impact we are having on the environment is huge,” said Matee. “It’s up to us to make this reality better. Start with whatever local solution you can find and be consistent with it. The results will be amazing.”

The United Nations Environment Programme’s Champions of the Earth and the Young Champions of the Earth honour individuals, groups and organizations whose actions have had a transformative impact on the environment.

The Young Champions of the Earth prize is the United Nations Environment Programme's leading initiative to engage youth in tackling the world's most pressing environmental challenges. Nzambi Matee is one of seven winners announced in December 2020, on the cusp of the UN Decade on Ecosystem Restoration 2021-2030.

By showcasing news of the significant work being done on the environmental frontlines these awards aim to inspire and motivate more people to act for nature. Both awards are part of UNEP’s #ForNature campaign to rally momentum for the UN Biodiversity Conference (COP 15) in Kunming in May 2021, and catalyze climate action all the way to the UN Climate Change Conference (COP26) in Glasgow in November 2021.