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.
We live in a society where waste is often disposed of without considering the cost to either the consumer or the producer. 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.
My research argues that this poorly disposed of waste also causes economic damage. To determine this economic damage, we compared the ongoing costs of poor waste management in 44 sub-Saharan African countries between now and 2060, with the costs of better waste management practices such as sanitary landfills and anaerobic digestion.
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.
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 our 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.
Our study of 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.
We assessed the damage caused by these emissions - one kilogram of methane emissions is estimated to cost, on average, US$1.943. Our research indicated that if we continued disposing of solid waste as we do now, the economic damage from methane emissions could reach billions of dollars. This cost seems to double every decade from 2025 to 2060.
While all sub-Saharan Africa countries are likely to experience some damage, certain countries could face costs running into billions of dollars. For example, by 2060, Ethiopia, Nigeria, the Democratic Republic of Congo, South Africa, and Tanzania could accumulate economic damages of US$6.7 billion, US$4.5 billion, US$4.7 billion, US$2.7 billion, and US$3.2 billion, respectively.
A Guest Editorial