Full Description

For the Los Angeles Department of Water and Power(LADWP), membrane filtration offered the best option fortreating water from the city's open reservoirs because thetechnology produced superior water quality, used minimal chemicals,required only a small footprint, and could be easily automated.Because of the lack of information about the comparativeperformance of major membrane filtration systems on high-qualityopen reservoir water, LADWP decided to pilot-test four membranesystems, two microfiltration and two ultrafiltration. In undertakingthis research, the utility hoped to obtain practical, objectivedata that would help develop design criteria for full-scale installationswith capacities of 6-10 mgd (23-38 ML/d).The membrane comparison considered a range of factorsincluding flux, rate of fouling, and frequency and efficiency ofchemical cleaning. Although all four systems tested producedsimilar quality water when the manufacturers' operating criteriawere followed, the pilot testing did uncover important differencesin flux, water recovery, and system maintenance. The key operatingfactors used in the city's final selection were the winningsystem's higher flux of 80 gfd (136 L/m2/h), its ability to withstandfeedwater pressure of up to 60 psi (414 kPa), its relatively higherwater recovery, and its resistance to a wide range of free chlorineconcentrations.By evaluating the performance of the membrane systems atpilot-scale using reservoir water, LADWP was able to pinpointthe different membranes' potential strengths and shortcomingsfor the project's specific requirements. In addition, the pilot testingproved valuable because it provided essential operationalinformation that could be used in the design of the full-scaleinstallations. Includes 10 references, tables, figures.

Product Details

Edition: Vol. 94 - No. 12 Published: 12/01/2002 Number of Pages: 8File Size: 1 file , 510 KB