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This powerpoint presentation begins by providing a brief overview of Zone 7 of Alameda County Flood Control andWater Conservation District and its three treatment facilities that serve theTri-Valley area (Livermore, California) that include: Patterson Pass Water Treatment Plant (WTP), 21.5 mgd;Del Valle WTP, 36 mgd; and,Altamont WTP, 24 mgd (in design). The purpose of evaluation was to:identify options to optimize the ultrafiltration (UF) WTPoperation and more reliably meet its existingcapacity of 8 million gallons per day (mgd); identify alternatives for increasing the UF WTPcapacity to 10-12 mgd; and,identify improvements for the conventionalplant. The approach included: a review of historical data;an on-site evaluation of operation; and,bench-scale testing. The issues identified included:diurnal pH and temperature fluctuations;algae growth in the Patterson Pass Reservoir and in thesolids contactor;return of neutralized citric acid from the washwaterrecovery system;membrane feed water quality;irrecoverable loss of membrane permeability;DHS flux limit;excessive backwash volume and reduced recovery; scheduling of backwashes, direct integrity tests, weeklycleanings;DIT fails to accurately predict broken fibers;recent excessive fiber breaks;weekly cleaning procedures include manual steps;limited indication on HMI;inlet and backwash valve failure; and,originally-installed Asi-networked control units are no longeravailable. Presentation conclusions indicate the following: replacement of membranes have dramaticallyimproved reliability;operations diligence has resolved many of theissues;now able to meet rated production of plant; and,start-up conditions may have contributed tomembrane performance issues. Includes tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 37File Size: 1 file , 1.2 MB