REDUCTION IN ORGANIC COMPOUND CONCENTRATIONS USING WELL INTAKES FOR SWRO FACILITIES IN THE CARIBBEAN AND THE RED SEA OF SAUDI ARABIA

摘要

Subsurface intake systems are generally believed to deliver higher quality of feed watercompared to open-ocean intake systems. Some new research results are reported from severaldesalination plants; two plants located on the Red Sea and one on the Caribbean Sea. Thesefacilities were assessed to compare the feedwater fouling potential of the open-ecean with thewell intakes.A water quality assessment was constructed by quantifying the organics content fraction,transparent exopolymer particle (TEP) concentration, and microorganism (algae and bacteria)concentrations. The results were then used to evaluate the performance of the well intake system,which currently is not well documented.Sampling points at the plants include the seawater as background data representing the openoceanfeedwater and the well discharge representing the subsurface intake raw water. LCOCDanalyses on the organic fractions showed complete removal of the biopolymer fraction in thewell discharge compared to the seawater. Other defined fractions, including humic acid and lowmolecular weight compounds, are also reduced in the well water. Flow-cytometer measurementswere used to quantify bacteria and algal clusters (Cyanobacteria, Prochlorococcus sp., andpicoano plankton). It was found that seawater contained nearly 10~5 cells/mL of algae and about106 cells/mL of bacteria. Interestingly, algae and bacteria exist at an insignificant number of cellsin the well discharge, indicating a microbiologically stable water. In addition, the TEP, whichgenerally is believed to be one of the precursors to membrane biofouling, was found reduced inthe well discharge, indicating a lower fouling potential of water.