Control of RO/NF organic fouling by monitoring and modification of organic polarity of feed water

Abstract

The organics in surface water and treated wastewater were analyzed for their polarity by a modified natural organic matter polarity rapid assessment method (NOM-PRAM). Selected water samples were then introduced to reverse osmosis (RO) and nanofiltration (NF) membrane system to study the relationship between organics polarity and membrane fouling. Results showed that the more organic fractions with non-polar property, the more serious fouling found for both RO and NF. Pre-treatment with KMnO4 was then conducted to modify the organics polarity in feed water. Under the optimum dosage, where more non-polar organics were converted to polar or negatively charged fractions, the subsequent membrane fouling was found to be reduced. © IWA Publishing 2008.