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From the GMA Techline
Subject: Geocomposite drainage — Canadian landfills apparently have not been allowed to use geocomposite drainage materials in lieu of 2 feet of gravel because they have to prove it will not clog for a period of up to 100 years. Have you studied this in the various geocomposites on the market or been to Canada to present your findings? (John, Illinois)
Reply: Thanks for your question. Back in 1985, the state of Pennsylvania felt uneasy about geonets so we did a full-scale experiment on a landfill cell measuring about 400m by 50m. It was double-lined with a geonet between the primary and secondary geomembranes. Both were 1.5mm smooth HDPE. We injected a truckload of water in the high end of the geonet and waited until it flowed to the outlet sump measuring the time for all to appear. We then repeated the test with waste in the landfill cell and repeated the experiment. Each iteration it took longer, but all of the input water did appear. Of course the normal stress applied load that caused intrusion of the geomembranes into the void space of the geonet. It was a pretty neat set of tests. At any rate it convinced the local regulators and Pennsylvania has used geonets ever since.
Now … will that convince your Canadian regulators and does it address the 100-year clogging issue? I doubt it, but I do remember that Ottawa once had in its regs that the geomembrane had to last in “perpetuity.” Things might change. They might even look into gravel clogging. I have seen several cases of “biorock.”
I don’t know if the above helps. But it’s after 5 p.m. on Friday and my wife is waiting on the back porch with a glass of white wine, so I will sign off accordingly … Bob Koerner