Low Fouling Reverse Osmosis Membranes: Evidence to the Contrary on Microfiltered Secondary Effluent
Orange County Water District and West Basin Municipal Water District recently conducted independent studies to determine if the latest RO membranes to hit the market, which claimed to be low fouling or fouling resistant membranes, actually achieved better operating characteristics and lower operating pressures than previous thin film composite membranes. In 2001-2002, OCWD tested three low fouling membranes on microfiltered secondary effluent from Orange County Sanitation District.
In 2001-2002, WBMWD under a research grant, operated two different low fouling membranes in parallel for a period of seven months; and compared the performance of these membranes with regular thin film composite membranes on full-scale MF/RO facilities. This paper will focus on OCWD and WBMWD and why both agencies continue to pilot test RO membrane before and after their projects are completed. The paper will address the results of the testing from both agencies, which have shown that the low fouling membranes did not operate at lower operating pressure than the previous membranes. Additionally, the paper will focus on the differences in the fouling characteristics of RO membranes for two different wastewater sources.