The United Nation’s 2009 Africa Review Report on Waste Management paints an alarming picture of the situation in Africa. The report indicates widespread dumping of waste into waterways and standing bodies of water, and unregulated dumping into landfills. A holistic solution is required to swerve a waste catastrophe.
Currently, only a minute fraction of Africa’s waste is recycled or composted. One problem with widespread dumping is the release of biogas emissions. Abandoned landfills continue to release greenhouse gases (GHG) long after their service life. In the absence of modern processing facilities, such as those with anaerobic digestion, the lost biogas serves as a major contributor to global warming and poses a significant challenge.
According to Africa’s waste profile, on average, more than half of African countries’ waste is “wet organic” (i.e., largely food materials). This type of waste is a prominent source of GHG, in the form of bio-methane, when disposed in landfills and dumpsites. In addition, Africa’s raw Municipal Solid Waste (MSW) consists of approximately 8% paper and 7% plastics. If properly sorted and processed these wastes can be transformed into sources of energy and financial revenue.
Current Status of Waste Management
Today, Africa’s biogas emission from food waste remains unharvested, and the vast majority of the dry unrecyclable residual waste is lost in landfills and dumpsites. What does this mean? When released from landfills and dumpsites, biogas contributes to global warming. It also represents lost value, as the biogas can be used to create vehicle fuel, and the unrecyclable residual waste can be converted to biofuels and other hydrocarbon based materials. The amount of gross energy lost from the absence of proper thermo-chemical treatment of dry residual unrecyclable waste in Africa is equivalent to more than 300 thousand barrels of crude oil per day, i.e., about 3% of the total oil production of these African countries, not counting North Africa. At the prevailing crude price, the amount of money buried in African landfills annually could be between $5-13 billion. In addition, the total estimated cost of waste management for all of Africa, excluding North Africa, is about $4 billion per year. In this estimate, waste collection makes up more than 70% of the costs, indicating gross inefficiencies in collection systems. These elements highlight the exigent need for the establishment of modern processing facilities and reforming of existing waste management mechanisms in Africa.
By 2025, Africa’s urban population will more than double to 522 million people. The amount of MSW generated is expected to increase by more than 85% in the next ten years. Africa needs a sustainable solution for its waste problem; one where MSW is treated effectively in recycling facilities located at reasonable distances (i.e., 30-50 Kilometers) from urban centers, thereby preventing cities from turning into landfills. In the absence of such a solution and with the growth of urban centers, collection and transportation of waste to available disposal areas will be cost-prohibitive, turning city edges into dumping areas and disease-promoting slums. The growth of slums as a product of urbanization, coupled with governments’ slow response programs, will result in the further increase of poverty and give rise to social and political instability. Therefore, the failure to manage Africa’s waste problem will have significant environmental, health, economic and political impacts.
Elements of a Solution
For optimal cost-effective results, MSW should be sorted using mechanical and optical technologies to extract: (i) wet organic waste (e.g., food and yard waste) for anaerobic digestion to produce biogas and compost; (ii) recyclables (e.g., plastic bottles, cardboard, paper, metals, glass and ceramics); and (iii) residual mixed unrecyclable waste (e.g., film plastics, plastic cups & plates, dirty unrecyclable paper & cardboard, diapers, and wood chips) for Advanced Thermal Treatment (ATT) to produce biofuels. One of the main types of ATT is pyrolysis, which is the thermal decomposition of organic material, in the absence of air, into lighter compounds including combustible gases, liquids and char. Unlike traditional modes of waste treatment such as incineration, pyrolysis does not burn raw wastes, which contain harmful components such as chlorinated plastics and batteries. This series of sorting, anaerobic digestion, and ATT are ideally combined and performed in an Integrated Materials and Energy Recovery Facility (IMERF).
An IMERF is a waste-to-energy plant where waste materials are delivered, sorted, treated, and converted into various forms of energy. For example, IMERFs remove the harmful impurities during the sorting operation, and then pyrolysis converts the bulk of the unrecyclable waste, mostly paper and plastics, to clean bio-oil. The recovered bio-oil can be used for onsite power generation, or the production of methanol, and other energy products. The advantage of these integrated models is the reduction in the amount of residual waste, such as broken glass, and other material. This minimum remaining waste can either be sent to landfills or recycled in high temperature industrial processes, such as cement plants, which are abundant in Africa. Therefore, IMERFs provide an optimal solution for Africa’s waste recovery and management problem.
An Effective Strategy?
An effective continental waste management strategy in Africa should begin with the largest urban population centers, such as Lagos, Addis Ababa, Nairobi, Maputo, Johannesburg, and Kampala. If by 2025, 860 IMERFs were created with an average capacity of 600 tons per day (enough to manage the current average waste output of Africa’s largest urban centers), expandable to 1500 tons per day, this could transform Africa’s waste problem into one of the key foundations for a sustainable economic system. If implemented properly, by 2025, the 860 IMERFs across Africa would have the capacity to process 440 thousand tons of MSW per day, and recover 58 thousand tons of recyclable commodities per day with a value of up to $200 per ton. In addition, each day they could recover 85 thousand tons of compost, 600 million cubic feet of biogas, and generate up to 3GW (Gigawatt) of renewable electric power. The latter could satisfy about 5% of Africa’s electric power needs. Although IMERFs are generally expected to have a payback period of less than 10 years, and only have a 20-year service life, modern IMERFs could last well over 40 years, and could be easily modernized and expanded to more than double their capacity, in order to meet the demands by 2050.
The total required capital expenditure for this program is an estimated $10.7 billion per year (less than $10 per capita) over 10 years of development. Modern IMERFs could generate more than $15 billion of annual net revenue from waste treatment fees, sales of recyclable commodities, compost, biogas, and renewable electric power. With international capital available and in search for opportunities, Africa can attract foreign investment into the waste reclamation sector by taking decisive and comprehensive actions, including optimizing waste collection to reduce costs for waste transportation, legislating disposal fees for waste generators, and providing exemption for segregators. All of the above should be combined with mass education programs about recycling, the environment, and sustainability.
In short, a unified continent-wide approach to Africa’s waste management problems may help accelerate adoption by creating a wider African market for recyclable commodities, renewable electric power and biogas, and for sharing know-how and gained experience.