11.8.3: Sanitary Landfills and Combustion
Much of the trash we produce ends up in landfills, which are essentially encapsulated and buried under layers of dirt. In order to protect groundwater and surface water from potentially toxic leachate - liquids that accrue from the decomposition of waste - the sanitary landfill needs to be lined with plastic and have adequate drainage. The leachate may be collected and treated before it too is stored. Additionally, decomposition of waste produces gasses and heat - which can cause emissions or even catch fire if not properly vented. Sometimes the methane produced by a landfill can be collected, treated, and used for energy. After waste is dumped into the landfill, it needs to be covered with soil in order to prevent pests (rodents, birds, or insects) from getting into it or the wind from blowing it out of the landfill (Frumkin, 2016). It may seem obvious that landfills are limited by capacity and location: no one wants to live near a landfill, and what should be done once the landfill is full?
Combustion of waste is another option. Although open incineration of trash was often practiced in backyards up until the mid 20th century, this practice creates high levels of pollution - particulate matter and GHGs - that pose a risk to the community and planet. The Clean Air Act of 1970 essentially put an end to this practice in the U.S., although it is still common in other developing countries. Incinerators in the U.S. can be used to produce energy and get rid of waste, but they must have expensive technology to reduce air pollution. The resulting ash can also become problematic to dispose of (Frumkin, 2016, Seabert et al., 2021).