What Are the Impacts of Landfill Mining?
According to the 2016 World Bank report, “What a Waste: A Global Review of Solid Waste Management”, Nigeria produced 34.6 million tonnes of waste a year. There’s a prediction that there will be 54.8 million tonnes of solid waste by 2030 and 107 million tonnes in 2050.
A large quantity of waste daily produced goes to landfill. Landfills are locations on land where waste products and garbage are kept. It is one of the principal methods of waste disposal, despite its negative impacts on the environment. Two-thirds of landfill waste is biodegradable. The waste releases carbon dioxide and methane into the atmosphere, which is toxic and contributes to global warming.
Landfills also pollute the soil and groundwater in the area, releasing dangerous chemicals to the environment.
Landfill Mining
The solution to the environmental challenges caused by landfill is landfills mining. Landfill mining is a process whereby solid wastes are excavated and processed typically from an active or closed landfill to reduce their environmental impacts. It is a commonly used strategy for significant materials recovery, land reclamation, and air and water pollution reduction. The excavated soil is processed to recover valuable recyclable materials, such as metals (aluminum, copper, etc.) and combustible materials (wood and other bio-based materials) for producing energy from waste.
The landfill mining process involves a series of operations based on the principle, primarily to excavate, sieve, and sort. Machinery commonly used are excavators, magnet, odor control sprayer, trammel screen, conveyor belts (for transporting the excavated materials), front end loader. These soils are decontaminated, and hazardous wastes are contained for disposal. Land reclaimed is regraded, and the topsoil covered.
Impacts
The major impact of landfill mining is that it removes dangerous materials from landfills and mitigates land and water pollution associated with landfills. Landfill mining offers the environmental advantage of cleaning up old landfills that contaminate the soil and groundwater through leaching and runoff that contain toxic materials, minerals, organic chemicals, and pathogens.
Besides the environmental impacts, landfill mining has economic consequences, which are significant to waste management firms. The recovered material like metals, plastic, aluminum during mining can be sold if markets exist for these materials. The soil reclaimed can also be used as a cover material on other landfill cells on sites. This is an excellent way of reducing the cost of the importation of cover material. A readily available market also exists for reclaimed soil such as compost. More so, combustible reclaimed waste can be mixed with fresh manure and burned to produce heat and energy.
However, landfill mining entails some environmental risks. The excavation and separation processes allow the emission of methane and volatile organic compounds. Carbon dioxide can also be released during the operation of production equipment. The handling of cyanogenic materials and medical waste causes danger to human health and the atmosphere.
Despite the risks involved in landfill mining, it has a lot to offer because landfills are still the primary waste disposal method. Its mining can only mitigate the environmental hazards associated with it. Landfill mining can be complicated and therefore requires a long-term view of economic and ecological considerations. In general, it is a tool to accomplish an enhanced circular economy model.
Author: Adelowo Oguntola
Picture Credit: emeraldsystemsinc
