RISK-BASED ENGINEERING DESIGN FOR A LANDFILL LEACHATE COLLECTION AND LINER SYSTEM

A methodology is used to identify the tradeoffs between costs and expo sure risk associated with landfill leachate collection and low permeab le systems. The results are useful in demonstrating the point at which additional levels of sophistication in design of a leachate/liner sys tem do not produce significant reductions of exposure risk. The case s tudy application to the Durham Regional landfill demonstrates that cla y liner hydraulic conductivity is the parameter with the largest influ ence on the risk of exceedance at the point of compliance. When the un derlying clay is more permeable, there is a significant merit associat ed with use of a QA/QC program.