Waste Disposal Sites
In the past, household wastes were often left to rot in
the open, whether in a centralized dump or on the landowner's
property. Today, garbage is disposed of in regional or municipal
sanitary landfills. These landfills are lined with clay or a
strong polyethylene liner to prevent any materials from leaching into
the groundwater. Leachates create the potential for soil and
groundwater contamination. At the end of each day new compacted
garbage is covered with a layer of soil. When the landfill
is full, it is capped with clay to make it air and water-tight. Materials
do not decompose very quickly in the absence of air and water.
This process minimizes the amount of material that could decompose and perhaps
contaminate groundwater or the surrounding land. The clay is
covered with fill (poor grade soil) and topsoil to provide a medium for
the growth of vegetation or other uses. Contouring the site
creates proper drainage and prepares it for seeding. Today, sites
for sanitary landfills are chosen after soil and water studies are
carried out and impacts on the environment, including people, have been
considered.