Answer:
Step-by-step explanation:
Landfills before sanitary landfills were mostly open dumps where waste was piled up without any control or treatment. These dumps were unsanitary, smelly, and attracted pests and diseases. They also polluted the soil, water, and air with toxic substances.
Sanitary landfills are a method of controlled disposal of municipal solid waste on land. They were first introduced in England in 1912 and gained wide use in the 1960s and 1970s. Waste is deposited in thin layers and compacted by heavy machinery. The waste is covered with soil or other materials to prevent odors, fires, and vermin. The landfill is also lined with clay and plastic to prevent leachate from contaminating groundwater.
Landfills have changed over time because of environmental concerns, regulations, and technological innovations. Modern landfills are designed to minimize environmental impacts, recover resources, and generate energy. Some examples of landfill improvements are:
Leachate collection and treatment systems that capture and clean the liquid that passes through the landfill
Gas recovery systems that capture and use the methane gas produced by decomposing waste
Recycling programs that separate reusable materials from waste before disposal
Waste-to-energy plants that burn waste to produce electricity or heat