The landfill sites still take in new garbage even when they are filled to capacity. As the waste decomposes, these sites release harmful greenhouse gases. However, using the methane gas to generate energy instead could save the continent billions of dollars.
About 70% of municipal solid waste ends up in landfills or unregulated dumpsites. In sub-Saharan Africa, for instance, 24% of waste is disposed of in landfills, while the rest is left on open dumps, streets, rivers, and other unsuitable locations.
Waste decomposing in landfills releases greenhouse gases. The release of carbon dioxide, nitrates and hydrogen sulfides can harm people’s health, either by polluting the air we breathe or contaminating nearby water sources.
Anaerobic digestion is a natural process that uses an anaerobic digester (a sealed container) in which microorganisms such as bacteria convert organic waste into biogas. The most energy-rich component of biogas is methane, which makes up 50–75% of its content, depending on the type of waste and operating conditions.
Anaerobic digestion also converts organic waste into digestate, which is organic fertiliser useful for gardening or farming. Cities in Europe have used anaerobic digestion to convert organic matter found in municipal solid waste into electricity, cooking gas and heat for the past 20 years.
Sanitary landfills are municipal dumps where wells and pipes are installed to collect landfill gas, which is about 50% methane and 50% carbon dioxide, with a few other compounds. This gas can be used to generate electricity, to fuel boilers, or processed for use in vehicles. Sanitary landfills are also designed to prevent pollutants from escaping into the air, soil, or groundwater. To be effective, they need to be properly located, built, maintained, and operated.
This in turn reduces the economic costs of problems like habitat loss, property damage, disease spread, and soil and water contamination. Our research showed that the cost of installing sanitary landfill and anaerobic digestion technologies to convert waste into energy is only a fraction of the economic damage caused by methane emissions. These green technologies are cost-effective solutions for tackling the high economic costs of climate damage.
Secondly, the methane contained in organic waste can be a renewable energy source. This renewable energy source would help us decrease our reliance on fossil fuels. This would mean lower energy costs, more energy security, and less environmental and economic damage from fossil fuel use.
According to research, by 2060, Sub-Saharan African countries could generate between 20 and 58 million MWh of electricity just from waste. This could provide each African with an extra 100–230 kWh of electricity. From 2035 to 2060, the top twenty countries could produce between 0.2 and 3.3 million MWh to 0.4 and 8.5 million MWh of electricity from waste.
In addition, study conducted in 44 sub-Saharan African countries was quite revealing. All 44 countries use landfills to dispose of waste. What stood out was that over 95% of these landfill sites in Africa are unregulated. The sites still accept waste even after they are full, and continue releasing greenhouse gases as the organic waste decomposes.
Countries with growing populations and economies, such as Ethiopia, Nigeria, the Democratic Republic of Congo, South Africa, Tanzania, Madagascar, Mozambique, and Uganda, could face economic losses exceeding US$2 billion each by 2060 if they do not clean up their landfill practices.
All African countries must introduce waste reduction, reuse, recycling, and energy recovery, promoting public health, reducing greenhouse gases, and supporting a green, circular economy. Sub-Saharan African countries should also adopt policies that promote private investment in the kind of clean waste management that leads to economic, social, and environmental benefits.
A Guest Editorial