Mathare woman turning slum waste into gold

Nancy Wanja displays the briquettes on January 6, 2023. To keep herself busy after high school, she participated in regular clean-up drives across Mlango Kubwa and Mabatini wards in Mathare Sub-county, Nairobi.

Photo credit: Moraa Obiria | Nation Media Group

What you need to know:

  • At least 23,000 Kenyans die annually from household air pollution arising from cooking with fossil fuels.
  • To keep herself busy after high school, Grace Wanja participated in  clean-up drives in Mathare Sub-county.
  • This prompted the idea of turning the organic waste into briquettes.
  • Part of our plan is to see schools in Mathare slums running a school feeding programme, adopt the briquettes.

Just 10 minutes into her cooking, using conventional charcoal, Grace Mutuku would feel dizzy.

It felt hotter inside her rented house in Mathare 4B, a slum settlement in Mathare Sub-County, Nairobi County, which she shared with her children.

She would open the door and window to ventilate and aerate the room.  Meanwhile, she stood outside the door to breath in fresh air.

Dizziness is a symptom of poisoning from carbon monoxide, a poisonous gas generated during the burning of charcoal.

At least 23,000 Kenyans die annually from household air pollution (HAP) arising from cooking with fossil fuels such as kerosene, firewood, crop waste and animal dung, according to Kenya Medical Research Institute.

Ms Mutuku can now be considered among Kenyans less likely to die from carbon monoxide poisoning. Why?

“I stopped feeling dizzy in August last year, when I started using briquettes,” she says.

I meet Ms Mutuku on January 6, 2023, buying briquettes from Motobrix Limited, a manufacturer of the eco-friendly fuel co-founded by Nancy Wanja, Calvin Shikuku and Edwin Odhiambo, all childhood friends brought up in Mathare.

Ms Wanja hands over the briquettes packed in a blue woven bag through a grill door after giving her a Sh50 ($0.40) note.

Ms Mutuku is one of the 200 Mathare residents who consume 1.5 tonnes of briquettes that Ms Wanja and her co-founders produce from organic waste, weekly, from their small factory in Mathare 4B.

They use charcoal dust, sawdust and fine paper collected from the local furniture workshops and schools.

Ms Mutuku is happy with the work of Ms Wanja and her colleagues.

“They have saved us from the high cost of charcoal,” she says.

“I put four briquettes in my large cooking stove and use it to cook soaked githeri (mix of beans and maize) for four hours. Thereafter, I boil drinking water without adding more,” she explains.

Grace Mutuku buys briquettes from Ms Wanja at their Mathare slum shop January 6, 2023.

Photo credit: Moraa Obiria | Nation Media Group

They retail a kilogramme of the eco-friendly fuel at Sh50 ($0.40). It has 13 cylindrical pieces.

With the conventional charcoal, she would use two tins of two-kilogramme each. One goes for Sh80 ($0.65).

This is the kind of impact Ms Wanja envisioned when they brainstormed the idea of recycling the organic waste in 2019.

An estimated 2.400 tons of solid waste is generated every day in Nairobi County  of which 58-63 per cent is organic waste.

Use of the eco-friendly briquettes contributes to reducing waste on the surface and minimises global warming.

Forestry expert attached to World Wide Fund for Nature-Kenya, Kiunga Kareko, says use of briquettes reduces cutting down of trees for firewood and charcoal, which then slows down global warming as trees serve as carbon sinks-they absorb and store carbon.

This is the carbon, which is then released to the air when they are burnt.

“When you’re burning charcoal or briquettes, in both cases you’ll still produce carbon but the advantage with the briquettes is in the production process and not in the utilisation process,” Mr Kiunga explains.

“When you’re making charcoal you do what we call carbonisation which produces carbon but when you do briquettes, you don’t do carbonisation but you compress the material into a compact unit.”

The briquettes are compressed, which means the biomass is compacted, hence, releases less carbon dioxide.

Carbonisation is the term used when complex carbonaceous substances such as wood or agricultural residues are broken down by heating into elemental carbon and chemical compounds which may also contain some carbon in their chemical structure.

In 2019, Ms Wanja had just finished high school and was waiting to join university for an undergraduate degree in Political Science, Public Administration and Sociology.

To keep herself busy, she participated in regular clean-up drives across Mlango Kubwa and Mabatini wards in Mathare Sub-county alongside her co-founders.

From the clean ups, they realised their efforts were yielding little fruit because the waste ended up in the public spaces.

This prompted the idea of turning the organic waste into briquettes.

Ms Wanja with her colleague Calvin Shikuku prepare raw materials for making eco-friendly briquettes at their factory in Mathare 4B, a slum settlement in Mathare Sub-County, Nairobi County on January 6, 2023. 

Photo credit: Moraa Obiria | Nation Media Group

They started co-producing with another youth group in Kasarani, a suburb of a mix of upper and low-income earners in the northeast side of Nairobi. The final product, however, wasn’t appealing to Mathare residents - it was brown, very heavy and looked like compressed sawdust. A kilogramme of the initial product had only three briquettes.

“Feedback from the consumers helped us improve our product to what it is now,” she says.

In 2019, they entered into a United Nations Children's Fund sponsored Generation Unlimited Youth Challenge, an initiative which nurtures youth who have identified solutions to problems in their communities. They won a Sh1.5 million $12,106) grant.

The win also came with training on conceptualising their idea and commercialising it to create employment for other youth in Mathare.

The prize money helped them start off - they bought the equipment, rented a room and hired 10 youths as business executives to market their products in five wards in Mathare sub-county namely Mabatini, Mlango Kubwa, Huruma, Kiamaiko and Hospital.

Of the 10 youths, six are women; all in the 18-24 age bracket.

For now, the one room serves as their factory and administration block besides housing the innovation centre, which they launched in January 2022, to nurture other upcoming entrepreneurs in the 18-24 age bracket, focused on waste management in Mathare Sub-county.

Local schools

In addition, they run weekly clean-ups, which supplement the waste they receive on Saturdays from two youth groups comprising 40 volunteers. 

Ms Wanja’s eyes are on the local schools that run feeding programmes, an initiative she says enabled her to finish primary school. She scored 370 marks in the Kenya Certificate of Primary Education.

“Part of our plan is to see all schools in Mathare running a school feeding programme, adopt the briquettes because we know just how much that meal means to the pupils,” says Ms Wanja who went through primary school courtesy of a well-wisher.

“But then there were days we wouldn’t have the meal because there was no firewood,” she recalls.

Ms Wanja was raised in a household headed by her mother, who until now is a tailor.

Her co-founder, Calvin Shikuku too, can relate to the pain of missing food at school.

“To me, the feeding programme was an incentive. I would not have gone to school had there not been food provided,” he says.

Sadly, occasionally, the programme would be put on hold because of lack of firewood to prepare the meals, he says.

Mr Shikuku was raised by his aunt who earned her income from doing laundry work in the middle-class neighbourhoods. 

It was unreliable work - some days she was lucky, while others passed by like a fold - and the earnings were too little to provide three meals a day and save enough to clear rent arrears.

The meals at school saved him from falling into the trap of “committing crime to get food.”

He now plays the role of the chief executive officer, which puts him in the position of actively thinking about the sustainability of the start-up, competitiveness of their products and finding new funding partners.

He is also a self-taught production engineer; the hands behind the compressed cylindrical briquettes.

“I’ve learnt how to make the briquettes through YouTube and research,” says Mr Shikuku who has a certificate in film technology. 

Trained staff

“But once we grow, the position will be filled by a trained staff,” says Mr Shikuku who hopes to enrol for a degree in Business Management to skill himself with techniques of growing their enterprise.

The five-step production process which involves collection of raw materials, sorting out, mixing, binding and compressing, takes two days.

Thereafter, the wet briquettes are dried in an electricity powered drier for 36 hours. 

But the process may take longer if there is a disconnection of electricity supply. Lack of power cripples the process since their machinery is only powered by electricity.

Sun-drying is inefficient and costly as they lose customers in the process. It takes three to four days. But can stretch into a week in rainy seasons.

Currently, they say, unreliable supply of electricity is a major    hurting their business.

When we met on January 6, the trio were only three days into operation in the New Year after two months of being out of business due to electricity disconnection.

They claim Kenya Power, an electricity supply company in Kenya, failed to promptly repair a faulty transformer that supplied power in their neighbourhood, despite the residents raising a complaint in November last year.


During the wait for power reconnection, they conducted community outreaches sensitising the people about their role in mitigating the impacts of climate change and mentoring upcoming entrepreneurs through the innovation centre.

Presently, they are incubating nine mentees - five young women and four young men under the group Queening Africa. The cohort reuse braids to weave handbags.

Queening Africa co-founder Damaris Nyahondo, says they joined the innovation last year to get help in converting their idea into a tangible product.

“We had an idea but we didn’t know how to go about it,” she says.

“But Wanja and team mentored us through the idea stage to the start-up.”

Now, they make the handbags from the innovation centre, selling one at Sh1,800 ($14.53).

“Motobrix has also given us the space to make our bags and whenever they have guests, they call us to market our products,” she says.

For Ms Wanja, the future is promising.

“We look forward to seeing the youth we have mentored do more in recycling the waste,” she says.

“In three years, we will have reduced the waste ending up in public spaces and eventually mitigate the impacts of climate change,” she enthuses.

According to the Environmental Protection Act, if 35 per cent of waste is recycled, landfill waste will decrease by 65 per cent.

Recycling also promotes environmental conservation as it reduces pressure on consumption of natural resources, such as timber, water and minerals, and prevents pollution by reducing the need to collect new raw materials.

Back to Ms Mutuku, her hope is that the government and non-governmental organisations would create awareness, especially among the slum residents on the alternative sources of eco-friendly fuel.

She says: “The government should also provide capital to the youth in every village in the slum areas to invest in the recycling of the waste. This will ensure we have enough briquettes for the households. We will also reduce the eyesore of piles of garbage everywhere.”

This story was produced with the support of Voice for Women and Girls' Rights-Kenya, a Journalists for Human Rights project.