Page 371 - Materials Chemistry, Second Edition

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342 Waste Management Practices: Municipal, Hazardous, and Industrial

FIGURE 10.30 Landfill cap under construction showing overlapping sheets of geomembrane cap.
Photo by Theresa M. Pichtel.

After a final cover is installed, the leachate collection system will have a very small leachate
load and should be relatively easy to maintain. Leachate generation should decrease to less than
9350 L/ha (1000 gal/acre) / day, which should not strain a system designed to handle storm waters.
During the postclosure period, leachate production rates should be monitored to detect any decrease
in production. If leachate generation falls markedly, the leachate pipes should be inspected for bio-
logical clogging. The LCR should be flushed if clogging is detected.
The vent pipes in a passive gas venting system must be inspected regularly for damage caused
by mowing or other traffic. A damaged vent pipe can allow surface water to enter the gas venting
system and bypass the cover. Damaged vent pipes must be repaired promptly. During the postclo-
sure period, groundwater monitoring must continue to be conducted on a routine basis. The facility
must be aware of any indications of contamination and must take necessary remedial action if con-
tamination occurs.