Page 320 - Materials Chemistry, Second Edition

CAT3525_C10.qxd 1/31/2005 12:00 PM Page 291
The Sanitary Landfill 291
or exceeded once in 100 years. Operators of landfills and lateral expansions located in 100 year
floodplains must demonstrate that the unit will not restrict the flow of the 100 year flood or result
in washout of any deposited MSW and therefore pose a hazard to health and the environment (40
CFR Part 258.11). “Washout” refers to the carrying away of solid waste by waters of the flood.

10.3.3 WETLANDS
The U.S. government regulatory definition of wetlands, as per Section 404 of the 1977 Clean Water
Act Amendments, is (33 CFR 328.3[b]) (also 40 CFR 232.2[r]):
those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient
to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for
life in saturated soil conditions. Wetlands generally include swamps, marshes bogs and similar areas.

New or expanding municipal landfills may not be built or expanded within wetlands. However,
exceptions can be made for units when the owner can show:

● No siting alternative is available.
● Operation will not violate applicable regulations on water quality or toxic effluent;
threaten endangered or threatened species or sensitive habitats; or violate protection of a
marine sanctuary.
● The unit will not cause or contribute to significant degradation of wetlands.
● Steps have been taken to achieve no net loss of wetlands (e.g., restoring damaged wet-
lands or creating man-made wetlands).

The landfill operator must demonstrate the integrity of the landfill unit and its ability to protect
local natural resources by addressing the following factors:

● Erosion, stability, and migration potential of native wetland soils used to support the unit
● The volume and chemical nature of the waste managed in the unit
● Impacts on aquatic and terrestrial wildlife and their habitat from release of the solid waste
● The potential effects of terrestrial catastrophic release of waste to the wetland and the
resulting impacts on the environment

10.3.4 FAULT AREAS
New units or lateral expansions are prohibited within 200 ft of fault areas that have shifted since
Holocene time (the most recent epoch of the Quaternary period, extending from the end of the
Pleistocene Epoch to the present) (40 CFR Part 258.13).

10.3.5 SEISMIC IMPACT ZONES
RCRA requires that landfills must not be sited in a seismic impact zone. In the event of siting in a poten-
tially unstable area, the landfill must be designed to withstand the effects of surface motion due to an
earthquake. All containment structures including liners, leachate collection systems, and surface-water
control systems must be designed to resist the maximum horizontal acceleration in earth material.

10.3.6 UNSTABLE AREAS

The landfill must be designed to ensure that the integrity of the unit will not be disrupted during
destabilizing events such as (U.S. EPA, 1993):

● Flows of debris from heavy rains
● Fast-forming sinkholes caused by excessive withdrawal of groundwater