Novel Nonporous Capillary Nanofiltration Membrane for Wastewater Treatment

U.S. industry generates large volumes of wastewater that contain suspended particulates, emulsified liquids, dissolved macromolecules, or dissolved organic compounds. Nanofiltration or ultrafiltration can produce dischargeable water from these streams. However, because current nanofiltration and ultrafiltration membranes are finely porous and only moderately hydrophilic, they are subject to fouling, particularly by particulates and macromolecules. Membrane fouling and the high maintenance and low system reliability that result have hindered widespread adoption of nanofiltration or ultrafiltration technology by producers of contaminated wastewaters. Membrane Technology and Research has developed a new type of composite nanofiltration/ultrafiltration membrane. These membranes do not allow particulate matter to enter the microporous substrate of the membrane; therefore, internal membrane fouling is eliminated. Development of fouling-resistant membranes will improve nanofiltration and ultrafiltration membrane performance by lowering capital costs, reducing energy consumption, and decreasing system down-time. In Phase I, these membranes will be formed into capillary hollow- fiber modules¿such modules offer good control of surface membrane fouling. These modules will be evaluated in side-by-side tests with commercially available capillary microporous membrane modules to verify the improved fouling resistance of the new membranes. If successfully developed, these membranes could make nanofiltration/ultrafiltration significantly more acceptable for treatment of industrial wastewater. These novel membranes will increase wastewater treatment options for the petrochemical, chemical process, food processing, and other industries.