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MWH and the City of San Diego have recently completed a pilot testing program at the North CityWater Reclamation Plant (NCWRP) located in San Diego, CA. The purpose of the testing program wasto evaluate various aspects of RO membrane integrity and integrity monitoring. During this study theintegrity of new generation RO membranes offered for water reuse applications was assessed usingtraditional methods such as vacuum decay testing, vessel probing, on-line conductivity and sulfatemonitoring and challenge testing with soluble dye and MS2 phage. In addition, a new method of ROintegrity monitoring developed by Nalco Company which uses TRASAR chemical was evaluated. Theability of the RO membranes to remove select endocrine disrupting compounds (EDCs) andpharmaceuticals and personal care products (PPCPs) was assessed by sampling feed and permeate ofeach system and evaluating them for a target list of 29 compounds commonly found in municipalwastewater. Lastly, the sensitivity of the tested integrity methods at detecting integrity breaches and theimpact of integrity on EDC/PPCP passage were determined by purposely breaching one of the ROmembrane systems and repeating testing. Results of this study showed the removal of MS2 phage bynew generation RO membranes varied between 2-4 log (i.e. 99%-99.99%). In addition, results of thevarious monitoring methods tested on each membrane correlated to MS2 removal; however, thesensitivity of the methods varied. For instance, conductivity monitoring provided ~2 log removal,sulfate monitoring ~3 log removal and soluble dye testing ~ 4 log removal. Challenge testing withTRASARshowed that the proposed method has the potential to provide a highly sensitive (6 log)level of integrity monitoring. EDC/PPCP analysis showed all intact new generation RO membranesystems tested removed select compounds present in the feed wastewater to levels near or below MDL(ng/L). Results also suggest that certain EDC/PPCP compounds have different removal mechanisms andtherefore, the increase in passage related to compromises in integrity may vary by compound and thetype of breach. Includes 11 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2006 Number of Pages: 16File Size: 1 file , 420 KB