AWWA MTC61232

Large-scale desalination facilities in North America are limited to open water intakes by economic and environmental considerations. Although open water intakes have been widely applied in the Middle East, Caribbean and other regions, there have been a limited number of full-scale facilities using open water intakes constructed in North America. Open water intakes are often associated with increased fouling loads resulting from phytoplankton, algae, marine flora and other particulates present in the raw water. Recent pilot studies performed using low-pressure membranes (microfiltration, ultrafiltration) to filter seawater from open water intakes have experienced operational challenges, including increased membrane fouling and particulate induced membrane damage. To mitigate these operational challenges, the authors have studied the application of disc filtration in lieu of fine-mesh strainers prior to the membrane systems. This paper outlines how operational challenges were mitigated at two pilot studies using disc filtration. It further reports on the results of controlled studies examining the benefits of disc filtration in enhancing the critical flux of low pressure membrane systems. A brief economic analysis on the benefits of disc filtration is presented. Includes 4 references, tables, figures.