AWWA MTC64643

The chemical properties of constituents found in seawater, particularly with respect to surface chemistry and colloidal interactions, have been shown by several researchers to vary greatly from those of non-brackish (fresh) surface water. As a result, an engineer's knowledge of coagulation, flocculation, sedimentation and filtration processes garnered from non-brackish surface water sources is not typically applicable to seawater pretreatment. Experience indicates that with a limited database of the performance of these processes treating seawater, bench and pilot scale testing is appropriate for any large scale desalination facility under consideration. This paper provides a review of published theoretical and applied research on pretreatment technologies for use in the treatment of seawater abstracted using open water intakes, as well as case studies documenting some of the state-of-the-art pretreatment technologies being utilized globally. Case studies examining the comparative performance of SWRO downstream utilizing feedwaters pretreated by conventional filtration and low-pressure membranes for two different pilot projects is examined. Includes 18 references, tables, figures.