AWWA MTC50270

Productivity and fouling control were investigated in four different Integrated Membrane System (IMS) schemes for surface water treatment that that included: scheme 1 - bankfiltration, aeration, dual media filtration, aeration, rapid sand filtration and nanofiltration; scheme 2 - coagulation, sedimentation, rapid sand filtration, transport, slow sand filtration and reverse osmosis; scheme 3 - coagulation, sedimentation, rapid sand filtration, transport, ozonation, biological activated carbon filtration, slow sand filtration and reverse osmosis; and, scheme 4 - storage, microstraining, coagulation, sedimentation, upflow filtration, ultrafiltration and reverse osmosis. In all four tested IMS schemes, MTC-decline was observed in operation times ranging from 9 to 14 months. Applied cleaning frequencies ranging from one to twelve times a year were quite acceptable. Bariumsulfate scaling occurred in scheme 4 after 9 months of operation. Current cleaning procedures were not successful. As a consequence antiscalant will be applied in the next test runs. Occasional increases in feed-concentrate pressure drop were observed in schemes 1 and 4. Cleanings of the nanofiltration and reverse osmosis elements were laborious. Consequently increases in feed-concentrate pressure drop should be avoided. Productivity of the ultrafiltration unit fed with pretreated surface water could be maintained at about 85 l/m2h, during a period of 18 months. Includes 7 references, tables, figures.