Newsletter and Technical Publications
<Municipal Solid Waste Management>
|Key considerations in landfill planning
- Required capacity
- Post-closure land use
The principal factors to consider in planning a landfill are the capacity of
the facility, the NIMBY (Not In My Back Yard) syndrome, the hydro-geology of the
proposed site, the cost of the facility, and post-closure use of the land.
Capacity refers to the area and volume required for MSW disposal over the
useful life of the facility. It depends on the pro-jected rate of waste
generation, the rate of population growth in the area served by the landfill,
the density to which the waste is compacted at the landfill, and the maximum
in-place elevation of MSW and cover material permitted at the site.
NIMBY refers to community opposition to the siting and operation of MSW
facilities close to their neighborhood. Residents express a variety of concerns
about the presence of such facilities in their midst. These concerns include:
- the health and environmental risks posed by the facility;
- its negative impact on aesthetics in the area, particular obnoxious odors;
- its lowering of property values;
- the increased traffic, noise and dust associated with the facility; and
- the inequity of dumping everyone elseÕs waste in their backyard.
Hydro-geology in the present context lumps together hydrological, geological,
and climatic factors. These include the height of the water table, the
hydrological conductivity of the soil, the characteristics of surface water, the
presence of wetlands and floodplains, the annual precipitation, the presence of
geological faults, and the degree of seismic activity in the area. Ideally, the
landfill should be sited in an area of low hydrological conductivity with a low
water table one that at its seasonal high point does not threaten to reach the
bottom of a new landfill. Sound practice dictates that landfills should not be
sited in wetlands, to avoid contamination of these ecologically sensitive areas.
Similarly, landfills should not be sited in floodplains, to minimize the risk of
washout of the buried waste during flooding. Such an event could pose
significant dangers to public health. Similar safety and health considerations
preclude the siting of landfills in seismically sensitive areas.
Costs are, of course, associated with all stages of the landfill from initial
siting and design through operation and final closure. These costs may be broken
into capital costs and operating costs. It is the capital costs which often
determine the type of facility that can be constructed. Once built, there are a
variety of mechanisms by which the operating costs of the facility may be
recovered. These will be discussed in the section on financing, below.
It is important to consider the planned post-closure use of the land in the
design of a landfill. Post-closure use will have an impact on how the land is
developed during use as a landfill. Thus, planned heavy building construction
will require the use of high density compaction equipment and the placement of
mooring on the site for this development. If recreational uses, such as golf
courses or parks, are planned, then the site must be graded with this in mind
and vegetation replanted on closed areas of the operating facility.