You are here:
DEMONSTRATION BULLETIN: MEMBRANE FILTRATION - SBP TECHNOLOGIES, INC.
Citation:
Science Applications International Corporation. DEMONSTRATION BULLETIN: MEMBRANE FILTRATION - SBP TECHNOLOGIES, INC. U.S. Environmental Protection Agency, Washington, DC, EPA/540/MR-92/014, 1992.
Impact/Purpose:
to inform the public
Description:
SBP Technologies Inc. (SBP) has developed a membrane-based separation technology that can reduce the volume of contaminated groundwater requiring treatment. The SBP Filtration Unit consists of porous, sintered, stainless steel tubes arranged in a shell-and-tube module configuration. Multi-layered inorganics and polymeric "formed-in-place" membranes are coated at microscopic thickness on the inside diameter of the porous stainless steel tubing by the recirculation of an aqueous slurry of membrane formation chemicals. This "formed-in-place" membrane functions as a hyperfiltration unit, removing species with molecular weights as low as 200. The formed-in-place membranes can be easily and readily modified to conform to waste characteristics and separation requirements. The filtration unit is operated in a crossflow mode where the feed stream is directed parallel to the surface of 'the membrane. The goal of the crossflow filtration is not to trap components within the pore structure of the membrane. In crossflow filtration, particulates and dissolved chemical species larger than the surface porosity are temporarily retarded on the membrane surface, and are then swept clean by the crossflow action. A portion of the fluid stream, along with smaller species, passes through the membrane. This process concentrates large species by reducing the volume of fluid in the crossflow stream. The product crossflow stream containing the excluded species is called the "concentrate." The material passing through the membrane is called the "permeate." In crossflow mode, the buildup of dissolved and particulate species on the surface of the membrane (fouling) is minimized by the parallel flow direction of the fluid. Periodic cleaning of the membrane is necessary when the buildup of materials becomes excessive.