AWWA MTC57625

After extended pilot research the ultrafiltration (UF)/reverse osmosis (RO) Heemskerk plant has been in operation for more than three years. With CS(GAC)F pretreated water, the UF is running at a flux of 113 L/m2.h. At low water temperature, a chemical cleaning with 500 mg/L NaOCl at 40 C is needed occasionally to restrict (bio)fouling. Chemically pure HCl and 0.5 mg/L Permatreat antiscalant are dosed into the RO feed to avoid biofouling and scaling. The RO plant is running with a flux of 28 L/m2.h without any chemical cleaning in the first three years. UF membrane integrity is monitored by 1.0 um particle counting in combination with measurement of 0.05 um particle counts once a week. When 0.05 um particle counts exceed 1500/mL, compromised fibers are plugged off. RO membrane integrity is monitored by sulfate measurements. In total, 8 log removal capacity can be established. Results show that system performance is excellent, all quality objectives are achieved easily and membrane integrity is very satisfying. Includes 4 references, tables, figures.