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Q: I’m reaching out to request your guidance regarding a technically demanding project from one of our clients. The application involves an exposed reservoir used to store blowdown water from industrial boilers, discharged at temperatures between 60 and 70 C, along with alternating acidic (pH 2) and basic (pH 12) liquid solutions. We understand that, as this is an open-air reservoir, the contact temperature on the geomembrane surface may stabilize closer to ambient temperature. However, we are concerned about the cumulative impact of repeated high-temperature discharges, combined with chemically aggressive solutions.
In addition, there is uncertainty as to whether the acid and base solutions are mixed prior to entering the reservoir, or whether the neutralization occurs inside. In the latter case, the geomembrane could be exposed locally to unnaturalized, low or high pH solutions during initial contact – especially near discharge points. Given this scenario, I would like to ask for your opinion on the durability testing of HDPE geomembranes.
A: I think the durability of geomembranes is one of the hallmarks of HDPE geomembranes and the improvement over time should be celebrated. Please use GRI GM42 Standard Specification for “Test Methods, Test Properties and Testing Frequency for High Density Polyethylene (HDPE) Geomembrane used in Extreme Conditions” over conventional GRI GM13 HDPE geomembrane for this extreme application. This GRI GM42 specification covers high-density polyethylene (HDPE) geomembranes with a formulated sheet density of 0.945 g/ml, or higher, in the thickness range of 1.5 mm (60 mils) to 3.0 mm (120 mils). Both smooth and textured geomembranes are covered under in GRI GM42. This MQC specification sets forth a set of minima, physical, mechanical and chemical properties that must be met, or exceeded by the geomembrane being manufactured. In addition, this specification has greater stress cracking criteria and higher durability criteria (oven, QUVA and chlorine aging) than conventional HDPE. I think you will be impressed!
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