The best way to avoid the environmental problems of solid waste disposal
is to desist from generating wastes in the frst instance. Pollution prevention
programs aimed at this objective have become widespread. Recycling and reuse of
materials are ways to avoid waste generation. At the residential level
recycling programs for newspapers, glass, and metal containers have been
implemented. However, some municipal programs have been criticized for
increasing environmental emissions of air pollutants from the fuel combustion.
The ultimate land disposal methods used for municipal solid wastes are
land flling, land farming, and deep well injection. Land flling of solid wastes
involves the controlled disposal of solid wastes on or in the upper layer of
the Earth’s mantle, which has been excavated to a depth of about 13 ft. (4 m.).
When solid wastes are placed in sanitary landflls, biological, chemical, and
physical processes occur. Biological decay of organic materials occurs by either
aerobic or anaerobic processes, resulting in the evolution of gases or liquids.
The chemical oxidation of waste materials occurs, dissolving and leaching of
organic and inorganic materials by water and leachate moving through the fll
also occur.