Membrane fouling in the nanofiltration of landfill leachate and its impact on trace contaminant removal

Nanofiltration (NF) is an attractive option for the treatment of landfill leachate. However, membrane fouling can be a major obstacle in the implementation of this technology. In this study, bench-scale filtration experiments were carried out to study the fouling behaviour during the NF of a synthetic landfill leachate. The results indicate that calcium in combination with organic matter could play a major role in governing the fouling process. Membrane fouling depended on the calcium concentration in the feed solution. Moreover, the results also indicate a significant influence of membrane fouling on the retention of Bisphenol A (BPA). It was hypothesised that pore blocking and the presence of the fouling layer resulted in an enhanced sieving effect, which subsequently increased the retention of BPA. On the other hand, cake layer enhanced concentration polarisation could hinder BPA from back diffusing into the bulk solution, which would eventually result in a lower BPA retention.