A landfill, also called sanitary landfill, is a land disposal site for waste, which is designed to protect from environmental pollution and health risks. Landfills are built to concentrate the waste in compacted layers to reduce the volume and monitored for the control of liquid and gaseous effluent in order to protect the environment and human health.
Besides municipal solid waste, faecal sludge can also be discharged into landfills. Well-constructed and maintained landfills are safer than open dumping sites, but even the best sanitary landfill will fill up and, after many years, probably start to leak. Therefore only waste, which cannot be reused further should be disposed of in landfills. To solve current waste problems, prevention of waste in the first place remains a priority. Separation of different types of wastes and reuse is much more sustainable.
A basic landfill is a pit with a protected bottom (to prevent contamination of groundwater) where trash is buried in layers, compacted and covered. Ideally, about 0.5 m of soil should cover the deposited refuse at the end of each day to prevent animals from digging up the waste, flies from breeding and to avoid that odor, waste (e.g. plastic bags) or pathogens are spread by the .The more advanced (“engineered”) landfills consist of a liner system at the bottom and the sides; a leachate removal system, which also includes a treatment of the leachate; groundwater monitoring, gas extraction (the gas is flared or used for energy production) and a cap system (see picture above). The capacity is planned and the site is chosen based on an environmental risk assessment study
Landfill leachates will cause environmental problems if not handled properly. One of the most promising methods of treating landfill leachate are constructed wetlands as they require little operation and maintenance Once the capacity of the landfill is reached, it has to be covered correctly and the bottom has to be controlled regularly to make sure no toxic effluent reaches groundwater sources. The cover should resist erosion by wind and water, promote vegetation and satisfy aesthetic, ecological, or end use criteria
Effective disposal method if managed well
Sanitary disposal method if managed effectively
Energy production and fast degradation if designed as a bioreactor landfill
Fills up quickly if waste is not reduced and reusable waste is not collected separately and recycled
A reasonably large area is required
Risk of groundwater contamination if not sealed correctly or the liner system is damaged
High costs for high-tech landfills
If not managed well, there is a risk of the landfill degenerating into an open dump
Once the landfill site is shut down O&M and monitoring must continue for the following 50 to 100 years