Many communities then use the areas for recreational purposes. Concern for the environment has led to the establishment of many strict laws and ordinances to control land disposal sites. Operators of early landfills expected organic wastes to decay. During the slow decomposition process, gases are released into the atmosphere and compounds are dissolved into the water in the landfill. The gases must be monitored and controlled to prevent air pollution.
Most new landfills have liners of plastic or clay to hold in contaminated water.
Rain water that drains into the landfill can be collected, pumped out, and transferred to a treatment plant for removal of contaminant. Few people want to live or work near a garbage disposal site. As it grows increasingly difficult to find locations for new landfills and incinerators, and as people have become more aware of environmental concerns, recycling and waste reduction have gained importance. In the mid-1990's, Americans buried about 57 percent of their municipal solid waste in landfills, recycled about 27 percent of it, and burned 16 percent in incinerators. Philip R. O'Leary, Ph.D., Associate Professor of Engineering Professional Development, Univ. of Wisconsin.