Ultrafiltration of laundry waste constituents

An experimental investigation is presented of the membrane ultrafiltration of several laundry waste constituents using a continuous flow, thin channel unit. Several tight, cellulose acetate and other polymeric membranes are studied. Only one type of membrane showed greater than 90% rejection of the anionic sodium laurylbenzene sulfonate, of the nonionic Triton X-100, and of poly- and orthophosphate. The membrane exhibited an average membrane resistance of 3.90 x 10⁸ N/m²/cm/sec. Several inorganic solutes at low concentrations cause an increase in water flux compared to solute free water. Most solutes produce little concentration polarization at the membrane surface. The membrane resistance for a synthetic laundry waste in distilled water is 4.13 x 10⁸ N/m²/cm/sec; however, the same solutes in tap water raise the resistance to 4.92 x 10⁸ N/m²/cm/sec. In both cases the rejection of surfactant, polyphosphate, and calcium was greater than 97%.