SANITARY LANDFILL OPERATIONS - Environmentally Conscious Materials Handling - page 212

Ta b l e 7 . 5 Land Use Examples of Closed Landfills (Tansel 1998)

Land Uses

Racetrack
Baseball facility
Model airplane field
Business park and golf course
Passive parkland and a small golf course
Soccer fields, tennis courts, boat launch, fishing area, amphitheater, sledding area
Public works storage facility and transfer station
Saltwater sailing lake, golf course, wetlands, levees, amphitheater, and wildlife refuge
Snow tube park and putt-putt golf
Recreation park, wildlife refuge, and butterfly garden
Ski slopes

End use must not interfere with monitoring and other postclosure requirements.
End-use features must be unaffected by subsidence, landfill gases, leachate, and
erosion. Typical end uses for closed landfills are presented in Table 7.5.

5.6 Long-Term Care

After the wastes are placed in a landfill, the weight of the wastes and the soil cover
cause further compression to take place. There is additional settling of completed
landfill as a result of decomposition reactions. The deposited materials go through
physical, chemical, and biological processes as wastes are decomposed. The
physical changes are compression and settling, dissolution and transport, and
absorption and adsorption. The water produced from chemical and biological
reactions forms a medium for the soluble substances to dissolve and causes the
unreacted materials to move.
Subtitle D of the Resource Conservation and Recovery Act (RCRA) requires
a postclosure period of 30 years for nonhazardous wastes in landfills. Postclosure
care (PCC) activities under Subtitle D include leachate collection and treatment,
groundwater monitoring, inspection and maintenance of the final cover, and mon-
itoring to ensure that landfill gas does not migrate off site or into on-site buildings.
According to solid waste facility regulations codified in 40 CFR §258 . 61(b), the
30-year PCC period specified by Subtitle D can be extended or shortened by the
governing regulatory agency on a site-specific basis. However, the decision to
extend or shorten the postclosure care period should be based on whether the
landfill is a threat to human health or the environment.
A landfill is considered functionally stable when it no longer presents an
unacceptable threat to human health and the environment. The landfill activity
depends on a number of factors, which include variables that relate to operations
both before and after the closure of a landfill cell. Therefore, PCC decisions
should be based on location-specific factors, operational factors, design factors,
postclosure performance, end use, and economic considerations.