The purpose of this module is to learn about municipal solid waste landfilling. Information will be provided that describes the components of a landfill, the processes which take place in a landfill, and basic landfill design. The majority of municipal solid waste both in the US and globally is placed in landfills. In developed countries, well-designed sanitary landfills are used which typically include bottom liners, leachate collection systems, leachate treatment, gas collection, gas treatment, final covers, and air and water monitoring systems. The modern landfill has evolved over the past 40 years from a long history of open dumps. Open dumps are still common in developing countries and potentially lead to adverse environmental impacts and threaten human health. Most countries have protective regulations in place that prescribe the design and operation of landfills, although they are not always enforced.

Within the landfill a complex sequence of chemical, physical, and biological processes occur that lead to waste degradation. These processes are naturally occurring but can be enhanced by controlling landfill internal conditions. The degradation processes lead to the emission of biogas and to the leaching of material from the landfill. Gas and leachate must be effectively managed to protect the environment. This module and the following two modules that address landfill leachate and gas management contain information, web links, and activities that will provide the reader in depth understanding of landfills and their role in managing of municipal solid waste.

By completing this landfill introduction module, you will be able to:

1. Develop a general familiarity with landfill topics and issues
2. Describe the main components of a modern landfill
3. Explain the landfill waste degradation process and the reactions involved