Demonstration of pilot-scale pervaporation systems for volatile organic compound removal from a surfactant enhanced aquifer remediation fluid I: Spiral wound membrane modules

Abstract

During the summer of 1996, a pilot-scale demonstration of a surfactant enhanced aquifer remediation (SEAR) process for removal of dense non-aqueous phase liquids (DNAPLs) from soils was conducted at Hill Air Force Base in Layton, Utah. Five thousand gallons of the extracted DNAPL-surfactant solution were transported to Cincinnati, Ohio, to be processed at the U.S. EPA's Test & Evaluation Facility, in a pervaporation pilot-scale unit equipped with spiral wound modules. The main DNAPLs in the extracted SEAR fluid were trichloroethylene (TCE) at 3,000 mg/L, 1,1,1-trichloroethane (TCA) at 450 mg/L, and tetrachloroethylene (PCE) at 400 mg/L. The solution also contained 2.5 wt% anionic surfactant, 1.5 wt% isopropyl alcohol, and 1.0 wt% salt. This demonstration highlighted complications posed by secondary contaminants to this application of spiral wound modules. Thirteen runs were performed with commercially available spiral wound pervaporation modules at various flow rates and temperatures. Single-pass VOC removal ranged from 50% to 98%. In all cases, TCE removal was almost identical to TCA removal and both were easier to remove than PCE.