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

During the summer of 1996, a pilot-scale demonstration of a surfactant enha nced aquifer remediation (SEAR) process for removal of dense non-aqueous ph ase liquids (DNAPLs) from soils was conducted at Hill Air Force Base in Lay ton, Utah. Five thousand gallons of the extracted DNAPL-surfactant solution were transported to Cincinnati, Ohio, to be processed at the U.S. EPA's Te st & Evaluation Facility, in a pervaporation pilot-scale unit equipped with spiral wound modules. The main DNAPLs in the extracted SEAR fluid were tri chloroethylene (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. T his 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 f low 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 wer e easier to remove than PCE.