A LOW-PRESSURE ULTRAFILTRATION MEMBRANE SYSTEM FOR POTABLE WATER-SUPPLY TO DEVELOPING COMMUNITIES IN SOUTH-AFRICA

Three pilot studies were performed in different areas of South Africa, demonstrating that particulate and colloidal turbidity can be reduced to acceptable levels. By operating at a static manifold pressure of b etween 100 and 140 kPa and a constant flux of 30-40 l/m(2).h, up to 85 % removal of NOM and >90% reduction in colour was observed. No microbi ological indicator organisms were detected in any of the permeate samp les analyzed, During the operation of the membranes for more than 3 ye ars, a loss of only 5% of membrane area was experienced, and a membran e life of >5 years can therefore be expected. The use of polysulphone ultrafiltration capillary membranes at a low operating pressure is abl e to remove natural organic matter, reduce organic colour (humic and f ulvic substances) and partially disinfect the water. Ultrafiltration p rovides a simple and effective means for the production of potable wat er for small communities.