Q: I am working on a 60 mil (1.5 mm) high-density polyethylene (HDPE) that will receive septage leachate. The pH will be below 5 and probably lower. I am looking for technical literature on liner performance at pH levels possibly as low as 2. Thank you for your assistance.
A: There are several options. Due to the severity of the condition (actual pH in long-term contact with geomembrane, temperature, exposure time frame of containment, etc.), I would rank these options in the following order from good to best in regards to acid containment. Obviously, the installed cost will increase as you go down the list.
High-density polyethylene (HDPE)
Ethylene interpolymer alloy (EIA)
All these materials can perform in the toughest applications, including floating covers, tank farms, wastewater impoundments, landfill liner and more. If your application is unique, you may consider conduction compatibility testing per ASTM D5819, Standard Guide for Selecting Test Methods for Experimental Evaluation of Geosynthetic Durability. The guide will either instruct you to test the candidate geomembrane per ASTM D5322, Standard Practice for Laboratory Immersion Procedures for Evaluating the Chemical Resistance of Geosynthetics to Liquids, or ASTM D5496, Standard Practice for In Field Immersion Testing of Geosynthetics.