Biological Clogging Resistance of Tubular Drainage Geocomposites in Leachate Collection Layers

摘要

Although drainage geocomposites are frequently used for rainwater drainage or gas collection system in landfill covers,rntheir application in leachate collection layers is rather limited. The authors believe that a key limitation to their use inrnleachate collection is a lack of knowledge of their sensitivity to biological clogging, and its consequence on the capacityrnof the Leachate collection layer (LCL) to meet landfill regulations prevailing in the US and Canada. In the first section ofrnthis document, a literature review was conducted of the actual drainage needs applicable to the LCL. This review led tornthe conclusion that leachate flow potentially reaching the LCL over the lifespan of a “dry tomb” landfill is significantlyrnlower than what is required in the early stages of its life. This observation allowed for a larger tolerance to biologicalrnclogging of a drainage geocomposite if combined with a granular drainage layer meeting reasonable requirements withrnrespect to biological clogging resistance. In the second section of this paper, the long term performance of tubularrndrainage geocomposites was investigated. Fresh leachate originating from a class 2, non-hazardous landfill located inrnthe center of France, was circulated through a tubular drainage geocomposite during an eighteen months’ time periodrnunder anaerobic conditions, without any observation of clogging. In the third section of this paper, the results arernanalyzed and interpreted. Based on this research and analysis, it is suggested that the tested tubular drainagerngeocomposite could replace a fraction of the granular drainage layer of a Leachate Collection System (LCS) in a dryrntomb landfill.