Page 552 - Materials Chemistry, Second Edition

CAT3525_C17.qxd 1/27/2005 12:44 PM Page 523
Land Disposal of Hazardous Waste 523
Primary FML
Secondary FML
Filter layer

Primary LCR
Secondry LCR
Solid waste

Drain pipes
Drain pipes

Compacted clay liner
Native soil foundation

FIGURE 17.1 Schematic of a landfill base showing liners and leachate collection and removal
systems (U.S. EPA, 1989) with permission. Not to scale.

FIGURE 17.2 Geosynthetic landfill liner being installed. (Reproduced with kind permission of Tenax,
Baltimore, MD.)

detecting, collecting, and removing leaks of hazardous constituents through the top liner as early as
possible. The state regulatory agency specifies the design and operating conditions in the permit to
ensure that the leachate depth over the liner does not exceed 30 cm (1 ft). The requirements for a
leak detection system include that it be (40 CFR 264):
● Constructed with a bottom slope of 1% or more.
● Constructed of granular drainage materials with a hydraulic conductivity of 1x10 2
cm/sec or more and a thickness of 30.5 cm (12 in.) or more; or constructed of synthetic
2
or geonet drainage materials with a transmissivity of 3 10 5 m /sec or more.
● Constructed of materials that are chemically resistant to the waste present in the landfill
and the leachate expected to be generated, and of sufficient strength and thickness to pre-
vent collapse under the pressures exerted by overlying wastes, waste cover materials, and
heavy equipment used.