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.