Demonstration of pilot-scale pervaporation systems for volatile organic compound removal from a surfactant enhanced aquifer remediation fluid. II: Hollow fiber membrane modules

Pilot-scale demonstration of pervaporation-based removal of volatile organi c compounds from a surfactant enhanced aquifer remediation (SEAR) fluid has been conducted at U.S. EPA's Test & Evaluation Facility using hollow fiber membrane modules. The membranes consisted of microporous hydrophobic polyp ropylene fibers having a thin plasmapolymerized silicone layer on the outsi de surface. The SEAR fluid was allowed to flow through the fiber bores at 3 5-45 degreesC, while vacuum was pulled on the shell side. The SEAR fluid wa s obtained from a pilot-scale demonstration at Hill Air Force Base, Layton, Utah, and contained trichloroethylene (TCE) at 3,000 mg/L, 1, 1, 1-trichlo roethane (TCA) at 450 mg/L and tetrachloroethylene (PCE) at 400 mg/L along with 2.5 wt % anionic surfactant, 1.5 wt % isopropyl alcohol, 1 wt % salt a nd a small amount of nonvolatile oil/grease. The hollow fiber modules were run at flow rates of 0.25-1 gpm for a period of 8-10 hours every day for a total of six weeks along with a continuous 40-hour run using the SEAR fluid . The modules were never washed with any fluid. The performance of the holl ow fiber modules was stable and satisfactory vis-a-vis VOC removal and pres sure drop considerations.