Most people know landfills as basic garbage dumps. This is where municipal solid waste is taken to be disposed.
However, modern landfills are far more complicated than just a hole in the ground where garbage is dumped. The basic parts of a landfill:
- bottom liner system that separates the waste from groundwater;
- cells where the waste is stored within the landfill
- a system for collecting rain water that would otherwise run off into nearby streams and land;
- a collection system for contaminated water that has moved through the landfill and become contaminated (known as leachate)
- A covering cap that seals off the top of the landfill when the cells are full.
Many landfill operators are also looking to for ways to collect the methane that is formed during the breakdown of organic waste.
Further background on how landfills are managed can be found by clicking here.
According to the US Environmental Protection Agency (EPA) there are about 2,000 landfills operating in the US. Landfills remain the primary destination for municipal solid waste in North American and indeed around thr world.
Landfilling is controversial because of the nuisances of odour, the emission of greenhouse gases, the contamination of groundwater, explosion risks and the generally unsightly appearance of the sites. Early landfills were ugly, chaotic waste dumps and it has been difficult to overcome this image in spite of the many significant improvements in landfill design.
Even with design improvements it has become increasingly apparent that burying waste in landfills cannot be a long-term solution. Even if biogas is extracted correctly and its energy recovered efficiently, other potentially recoverable materials remain buried forever.