The primary leachate collection system of most solid waste landfills contains a filter layer which has historically been a granular soil. Recently, however, various types of geotextile filters have been used to replace the natural soil filters. A project using six different landfill leachates and aimed at investigating the functioning of different geotextile filters is the focus of this 36 month long study. The initial 12 months, referred to as Phase I, investigated flow rates in various filters under aerobic conditions at six different landfill sites using the site-specific leachates. The study inadvertently found that the overlying granular soil clogged as much as the geotextile filter that was located downstream. The effects of different types and styles of geotextiles was generally masked by the upstream soil clogging. An important finding in this task was the biodegradation of the geotextiles was not evidenced and was concluded to be a non-issue. The subsequent 24 months of study, referred to as Phase II(a), led to the development of a vastly improved flow rate monitoring device. In a separate task, referred to as Phase II(b) and conducted simultaneously with Phase II(a), biocide treated geosynthetics were utilized at the two sites with the most aggressive leachates. While the biocides may have been effective in killing microorganisms, the remnants were as troublesome as the viable bacteria in creating subsequent clogging.

"PB91-213660." "July 1991." Includes bibliographical references. Sponsored by the Risk Reduction Engineering Laboratory, Office of Research and Development, United States Environmental Protection Agency. Microfiche.