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Tapping the power of solid waste

Solid waste in Mulago, Kampala, 2010. Urban residents find a way to recycle waste into energy. SuSanA Secretariat/Flickr, CC BY-SA

When there is continuous failure for municipalities to collect and manage wastes, authorities tend to concentrate in a few areas, often in the wealthier sections of a city. Informal settlements in the remain underserved, with some parts not served at all, leading to accumulating of wastes.

Kampala, a city of 1.5 million residents, is growing at annual rate of 5.1%. This shows the speed at which medium-sized cities are growing. The expansion of the cities like Kampala makes service provision difficult due to poor roads and infrastructure to connect the neighbourhoods. Most housing and buildings are constructed ahead of formal planning, resulting in settlements that have inadequate services. About 87% of the residents in Kampala live in informal houses, 78% have access to electricity to their houses and only 17% have piped water. An estimated 1,300 tons/day of wastes are produced in the city and about 50% is collected and transported to the landfill.

In such context, the absence of waste management and sanitation have led residents to come up with solutions) that make usable products out of the organic waste materials. One such innovation is producing energy briquettes from both organic and human wastes, or fecal sludge.

Marketing energy briquettes. By Shuaib Lwasa

Innovations emerge from the informal sector

Our research show that in cities such as Kampala, many individuals benefit economically from this informal sector which improves waste management services and addresses climate change.

Turning waste into a reliable source of energy is not new. Examples can be found in India, Bangladesh, Bolivia and many others. The waste-to-energy method is designed primarily as climate change mitigation to reduce emissions, but also has a huge potential to address employment problems.

Turning organic waste in energy in Nepal.

This type of economic activity is not part of the official urban economic sector, yet can greatly contribute to the economy. It requires innovation, community and business involvement and support from researchers. A small briquette-making business with semi-mechanised moulding machine would require an estimated 15 million UGX (about 3,700 euros) to capitalise the business.

Its promises and the stakes involved for the community are high. In Kampala, we observed how its business model is being used to promote waste-to-energy in impoverished neighbourhoods to create jobs and expanded economic opportunities.

Tapping a free resource

Waste in general and solid organic waste in particular is a commodity that has not been looked as a resource. Making energy briquettes from organic wastes is not new as this has been in production in 1980s in Kampala, but the potential can be realised if businesses can grow to medium size. This can help in recovering uncollected waste materials from other neighbourhoods.

In Kampala, organic materials thrown away by residents such as food waste, plant leaves and stems, fecal sludge. This material is collected by the groups, dried to reduce water, crushed and made into a char. The char is then mixed with a binder such as sawdust, dirt or clay with a little water and fed into a moulding machine that produces briquettes of different sizes and types. The briquettes are then dried to reduce the moisture and packed for sale.

Seasoning energy briquettes. Shuaib Lwasa

Organic solid wastes produce greenhouse gasses when they decompose. A study in 2017 estimated a total of 69,522 t CO2 contributing 9.72% of the total emissions of Kampala. 87% of the emissions attributed to waste are produced at the landfill. Thus, businesses that reduce the wastes going to the landfill can cumulatively reduce greenhouse-gas emissions.

Booming “waste” labs in the slums

We worked with NGOs such as ACTogether (affiliated to Slum Dwellers International) to identify informal settlements for piloting the businesses. We conducted a baseline study on the nature and quantities of organic waste, flows, waste types and major sources in the neighbourhoods. This was followed by consultations with 10 community producing groups with an average of 15 members, both men and women, about the possibilities of scaling up the energy-briquette businesses.

We organised several meetings and training workshops covering topics of energy-briquette product development, business-plan development, branding and marketing as well as skills in bookkeeping and accounting. Community groups are at different levels in briquette making, with some experienced and producing as much as one ton per week while others were just starting.

The different community producing groups will be seeded for capital acquisition of fabricating machines, carbonising stoves, crushers and seasoning racks, while established groups will require solar dryers, product branding and marketing drives.

The producing groups have established laboratories in the slums to test the different ingredients before rollout of the products for sales. Although some test products are used for promotion one of the selling pitch is the emissions reduction of the briquettes compared to charcoal.

A strong organisation

There are also some groups that collect and deliver the organic wastes to the fabricating groups. Some take it further, producing char that they sell to the groups that make briquettes. These are back-end businesses that are evolving, including hiring youths to collect organic wastes and transporting them to the production units, while a front-end businesses involving community members and youths groups is emerging around specialisation on producing char then sold to fabricators.

Briquette machine. Shuaib Lwasa, Author provided

The community groups are establishing cooperatives for collective marketing of the briquettes. Thee cooperatives are working on quality control and standardisation since the groups produce briquettes independently.

Briquette quality control involves looking at the ingredients used, the carbonisation, mixing ratios and types of wastes used as a binder. The binder determines the length that a briquette will burn and thus its calorific value, which is the selling quality in comparison to competitor products such as charcoal.

Fecal sludge can provide jobs

More than 75% of the households in Kampala use pit latrines and only 13% are connected to the sewer network. This implies that only a small fraction of human waste is treated. An innovation has evolved where small businesses have been established to collect and transport human waste to the treatment plants. This emerging economic activity is creating jobs, which are growing from small to medium scale of operation.

Women and youth groups have developed waste-collection businesses that use the gulper technology to empty pit latrines and transport materials to sewerage treatment plants using tricycles with small tanks.

Continuous monitoring of GHG emissions from production through use by the households is important. The team has established a protocol for tracking emissions through periodic measurement at all the piloting production units during production and a few households who are close by that use the briquettes for cooking.

The branding will also include the information on the GHG emissions produced when briquettes are burned, and how much is saved to mitigate climate change. The hope using this method is that users will adopt the use of briquette as individual responsibility toward saving the planet from warming further.

Gulper technology to empty latrines.

A reproducible initiative

The amount of GHG generated by Kampala is negligible, relatively speaking, an estimated 200g per person and a total of 0.7 million tons of CO2 per year, but producing energy briquettes from solid organic waste is an innovation that can be adopted in other cities that are searching for alternative pathways to sustainability.

We are also working with youths groups that are interested in tapping the energy from fecal sludge by transforming it directly into energy briquettes. This process is still at its infancy compared to briquettes from solid organic waste, but it is worth looking at as we continue exploring pathways to sustainability that are inclusive, resilient and sustainable.


Created in 2007 to help accelerate and share scientific knowledge on key societal issues, the Axa Research Fund has been supporting nearly 600 projects around the world conducted by researchers from 54 countries. To learn more, visit the site of the Axa Research Fund.

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