DESIGN AND OPERATION OF ULTRAFILTRATION SYSTEMS FOR WATER TREATMENT.

摘要

Ultrafiltration (UF) is the process whereby dissolved molecules on the order of 1-10 nm in size and larger are removed from a solution by forcing the solvent through a synthetic membrane barrier under pressure. In order to evaluate the feasibility of UF for use as a water treatment process several studies were performed. A pilot plant incorporating spiral wound membrane modules was used to pre-treat a surface brackish water for reverse osmosis. The results were generally satisfactory, however, clogging of the spiral wound modules by suspended and colloidal particles necessitated a re-design of the system. Both primary and secondary sewage effluents were treated using specially constructed flat sheet devices to test newly developed membranes. It was found that secondary effluent could be treated effectively using UF while primary effluent could not. A pilot plant employing spiral wound modules containing a new spacer material was then used to treat secondary effluent with satisfactory results. The costs of UF for these purposes were found to be high relative to conventional chemical and biological water treatment methods, indicating that UF would be applicable in specialized applications, where conventional water treatment methods are themselves costly or impractical.