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The city of Jackson, Mississippi, is served by two surface water treatment plants: the 25-million-gallon-per-day (mgd) O.B. Curtis plant; and, the 42-mgd J.H. Fewell plant. Tomeet increasing water demands and future water quality regulations, the city is expandingthe O.B. Curtis facility to 50 mgd with the addition of a new 25 mgd ultrafiltration (UF)membrane facility. In addition to the onsite addition of the UF membrane plant,improvements include:expansion of the raw water pump station;modifications to the chemical systems and sedimentation basins;new ultraviolet (UV) disinfection for the conventional filters;addition of a second clear well; and, new conventional plant human machine interface/programmable logic controller(HMI/PLC) control system, high-service pump station, and closed circuit televisionsecurity system.Since the UF membrane facility will treat coagulated/flocculated water and then bepumped to the new clear well, controlling the raw water flow and chemical feed additionprior to its reaching the membrane system is critical. This paper demonstrates the difficulty ofincorporating the UF membrane plant instrumentation with the overall conventional plantsupervisory control and data acquisition (SCADA) system. To avoid problems in the construction phase, it was essential that considerationbe given during the design phase to process design, construction sequencing, andconventional plant HMI/PLC control systems design. Consideration also had to be givento merging the new stand-alone HMI/PLC UF membrane plant control system with thenew conventional plant HMI/PLC control system, thus forming a single plant-widecontrol system. Because the UF membrane operation relies on proper raw water flowrates and dosing of chemicals, responsibility for control of these systems belongs to theUF membrane manufacturer.This paper provides insight into the decision making process of the design team asthey worked together with the UF membrane system supplier to incorporate the new UFmembrane control system into the overall conventional plant control system.

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Edition: Vol. - No. Published: 06/01/2006 Number of Pages: 5File Size: 1 file , 230 KB