This is a question for our expert visitors.
The answer is: “Leakage Detection Layers”. We have quoted some text from a US landfill lining systems report.
“The double-composite liner system, …, consists of a primary liner overlaying a secondary liner with a leak detection layer between the two liners. Both the primary and secondary liners have two low permeable components. The leak detection layer is a layer between the two liners. The purpose of the leak detection layer is monitor the performance of the upper liner and allow appropriate action to be taken when leachate is found in this layer. This liner system has a leachate collection system directly above the primary liner.”
Just why the idea never took off in Europe is the next question. It has been suggested to your BlogMaster that the presence of the leak detection layer introduces an additional weakness, and this is probably the reason why it is disliked outside the US. After all, if the leak detection layer becomes contaminated the leachate in it might find a hole anywhere across the base to escape through due to the ability for it to flow through the detection layer material itself.
Also the theory has it that to spend equal money due to the cost of the detection layer, on Landfill CQA is a much better investment, after all the landfill owner will be monitoring outside the landfill for any escape of leachate, in any case, as a matter of good practice, so the leakage detection layer isn’t essential to detect any leak.
Continue to use the “comment” link below, and tell us what you think about the cross-atlantic differences in approach here. We would be delighted to see you views.