Waste and methane in Sub-Saharan Africa: what World Bank data say

According to the World Bank, the amount of municipal waste in Sub-Saharan Africa is to grow roughly threefold, from about 174 million t in 2016 to about 516 million t in 2050, and most of it today goes to uncontrolled dumps. These are data from the 2018 report "What a Waste 2.0". The combination of a large share of biodegradable waste, a low level of controlled landfilling and growing urbanisation makes the region both a source of significant methane emissions and a major opportunity for anaerobic digestion.

Global and regional scale

In the 2018 report the World Bank stated that 2.01 billion t of municipal waste were generated worldwide in 2016, and that by 2050 the amount is to rise to 3.40 billion t, that is, by 70%, if there are no policy changes. For Sub-Saharan Africa a study by the African Clean Cities Platform, citing this report (p. 28), indicates growth from about 174 million t in 2016 to about 516 million t in 2050, that is, about threefold. Phys.org gives a value of about 180 million t for 2016, that is, about 9% of the global amount. The discrepancy results from rounding and the definition of the region.

Composition: why organics matter so much

According to a commentary by Desta Mebratu (Phys.org, 2022), more than 60% of the waste generated in African cities is biodegradable, and a further about 20% is suitable for recycling. This is more than in many European countries, where packaging has a large share. The African Clean Cities Platform notes that as a country's wealth grows, the share of organic waste falls and that of plastic and paper rises. High moisture and susceptibility to rapid decomposition make this type of waste a poorer fuel for incinerators and a better substrate for anaerobic digestion and composting. The same material at a landfill generates methane and leachate.

How it is landfilled

Mebratu writes that in 2016 only about 11% of the region's waste went to properly designed and managed landfills, and more than 60% to open dumps; in many African cities up to 90% of waste goes to open dumps, and a considerable part is burned. The African Clean Cities Platform, citing the World Bank report (p. 82), indicates that at least 70% of waste in Sub-Saharan Africa is landfilled at uncontrolled dumps. The difference results from different definitions and data. The conclusion, however, is consistent: most waste is not landfilled in a controlled way, and so methane is not captured.

Climate and safety consequences

Methane from landfills has a large impact on the climate over a horizon of several decades. Besides emissions, landfill fires and landslides are at stake, a tragic example of which was the collapse of Kiteezi in Kampala in 2024 (Uganda: collapse of the Kiteezi landfill) and the earlier event at Koshe in Addis Ababa in March 2017 (see Reppie in Addis Ababa).

What can reduce emissions

1. Selective collection of biowaste (even in a simplified form, e.g. from markets and bazaars) is the first step.
2. Composting and digestion in installations of a scale matched to the city; a biogas plant yields energy, and the digestate a fertiliser.
3. Degassing of landfills and flaring or energy use of methane where landfilling remains necessary (see Landfill gas: degassing obligations).
4. Integration of the informal sector: waste pickers are part of the system and should have a place in it.
5. Financing: in many cities there are no funds for the running costs of collection, which are a condition for the functioning of any installation.

World Bank data make it possible to assess the scale, but they do not replace local waste composition studies: the biogas potential in a city depends on the real composition and the way of collection.

Where digestion makes sense and where it does not

Anaerobic digestion requires a relatively clean stream of biowaste. The African Clean Cities Platform indicates composting and methane fermentation as the main methods of managing organic waste, with composting not requiring advanced technology. From a mixed municipal waste stream, in which the organic fraction is contaminated with plastics, glass and metals, it can be separated at a sorting plant, but the material obtained is of poorer quality and the digestate is harder to use in agriculture. That is why in many cities the first step is often composting: cheaper, less sensitive to contamination, although it does not produce energy. Biogas plants work well where there is a large, relatively clean stream: wholesale markets, bazaars, food processing, abattoirs and large institutions. In Polish practice a comparison of the two solutions is presented in the article Composting or digestion of biowaste.

Why regional figures must be read with caution

World Bank data are based on country reports, which in Sub-Saharan Africa are often incomplete or based on estimates. Collection covers mainly central areas of cities, and waste generated on the periphery or burned on site is not included. Waste composition changes with income: in higher-income cities the share of packaging rises. For planning a specific installation, local waste composition studies are essential.