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 between 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 microbiological indicator organisms were detected in any of the permeate samples analyzed. During the operation of the membranes for more than 3 years, a loss of only 5% of membrane area was experienced, and a membrane life of >5 years can therefore be expected. The use of polysulphone ultrafiltration capillary membranes at a low operating pressure is able to remove natural organic matter, reduce organic colour (humic and fulvic substances) and partially disinfect the water. Ultrafiltration provides a simple and effective means for the production of potable water for small communities.