Physicist in Kenya creates bricks from plastic waste

In Nairobi, people generate 500 metric tons of waste per day. A very small percentage of that waste gets recycled. After quitting my job, I set up a small laboratory in my home. I used the laboratory to test pavers in order to derive the right ratios to make a paving brick.

  • 2 years ago
  • August 9, 2022
5 min read
Nzambi Matee pictured with the workers from Gjenge Makers LTD Nzambi Matee pictured with the workers from Gjenge Makers LTD | Photo courtesy of Nzambi Matee
Nzambi Matee
Interview Subject
Nzambi Matee is a Kenyan physicist and engineer who has made a bold step in conserving the environment. Matee holds a Bachelor of Science degree in physics from Jomo Kenyatta University.

After working in the oil and gas industry for a year and a half, Matee started Gjenge Makers LTD to turn plastic waste in bricks. Matee was named a Young Champion of the Eart by the United Nations Environment Programme in 2020 for her efforts.
Background Information
According to the 2020 State of Global air report, ambient air pollution caused about 5,000 premature deaths in Kenya in a single year. Industrial pollution, desertification, and deforestation are a few of the major causes of pollution in Kenya.

The government of Kenya stepped up efforts to mitigate the problem of plastic waste with a ban on the use of plastic bags. However, plastics such as bottles and utensils still remained in use. Today, tons of plastic waste litters the country.

NAIROBI, Kenya ꟷ Plastic pollution interrupted my family trip to the coastal city of Mombasa. There to swim and have fun, I could feel and see plastics and paper bags polluting the water.  It felt disgusting and unhealthy.

Back in my home city of Nairobi, plastic waste litters the streets and the Nairobi River. I felt myself growing tired of sitting on the sidelines. There, on the beaches of Mombasa, I wondered, “What more can I do?” An idea sparked inside me.

You rarely see metal waste in Nairobi because thousands of scrap dealers collect it and sell it to recyclers. I became convinced the same concept could apply to plastics, so I started my company Gjenge Makers LTD. The Swahili word Gjenge means “build yourself” and that is what my company stands for. At Gjenge, we make bricks from plastic. Using plastic waste as our raw material, we aim to curb environmental pollution.

Physicist pursues purpose, makes a paving brick out of plastic

After graduating from Jomo Kenyatta University with a Bachelor of Science degree in Physics, I took a job for a year and a half in the oil and gas industry. I never felt content there. I had no issues with the environment, my colleagues, or even the salary I earned. The job just did not match my calling and every single day I questioned, “Am I on earth to be doing this?”

A void grew inside of me and I decided one day, enough is enough. In 2016 I left oil and gas to pursue my passion for waste management. “Let me go and try something else,” I thought. “If it works well, that will be good. If it does not, I will go back to the drawing board.” The journey to establishing Gjenge began the following year, in 2017.

At the time of my transition, I knew Kenya had a big problem in waste management. Nairobi itself remained extremely littered, which has not changed much to date. I knew I could not eliminate the problem, but I believed I could provide some solution.

In Nairobi, people generate 500 metric tons of waste per day. A very small percentage of that waste gets recycled. After quitting my job, I set up a small laboratory in my home. I used the laboratory to test pavers in order to derive the right ratios to make a paving brick.

After some time, I successfully made the first brick from plastic waste, marking the beginning of Gjenge.

From one brick to large scale production

Inspired by the work of the late Professor Wangari Mathaai, I wanted to do something in environmental conversation. I remember watching her video, where she got hurt in a protest against the invasion of the Karura Forest. It motivated me.

 Activism served as her tool of the trade. My tool would be science, engineering, and technology.  Curiosity propelled me forward. The concept of using waste to make building products existed in other parts of the world. I simply needed to replicate it in Kenya.

In 2019, I made a machine to take production from small to large scale. A big problem I faced in increasing production came down to capital. A lack of capital can push innovation, however, you still need it. During the first year of the business, I danced to make money to fund the endeavor.

Now, the production process includes stages to obtain a market-ready finished product. First, we crush the waste plastic into small pieces, then mix the crushed plastics with sand. If color is needed, we add pigment. We then feed the mixture onto the extruder which heats it intensely to soften it to mold. We then measure it into small portions to produce different sized bricks.

The mold feeds into a hydraulic press to squeeze, shape, and produce many bricks at once. We cool the bricks to harden at room temperature, obtaining a finished product. Because plastic is fibrous in nature, the bricks gain a stronger compression. Our bricks end up as hard as concrete bricks.

Building a team and winning a United Nations prize

Current production can produce 1,000 to 15,000 bricks per day. Purchasers mainly use the bricks to construct pavement and roads around Nairobi. In addition to the benefit of reusing recycled material, we sell the bricks at 25 percent less than the cost of concrete bricks.

Along with over 100 employees now, we say our bricks are stronger, lighter, and more affordable. While we mostly operate in Nairobi, my big dream is to spread the business around Kenya. We aim to reach the whole country and give many young people a chance to learn about production and recycling.

Maybe they will become inspired to use littered plastics in their own cities and neighborhoods for something positive. Perhaps they will embrace the idea that they can be a part of something sustainable and healthy for the environment. As we grow, we add products. Currently, we are in the process of making roofing tiles from plastic waste.

Throughout this whole process, the most defining moment happened when I won the Young Champions of the Earth prize from the United Nations Environment Programme. The win felt as though someone said, “I see what you are doing, and I appreciate that.” The prize served as a huge motivation.

My greatest achievement, though, is my team. As the Gjenge founder, I could build a solution, but without a team to figure it all out and put the structures in place, it might not be so successful. My team is my greatest inspiration of all.

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