Comparison of pre-treatment methods for nanofiltration (NF) in drinking water treatment related with organic removal and membrane fouling mitigation

Nanofiltration is a promising technology for water engineering. However, membrane fouling is the major bottleneck for NF application. In this paper, four typical methods, in the drinking water treatment trains, were comprehensively studied for their effectiveness as NF pretreatments, based on the organic removal improvement and membrane fouling mitigation. It was found that coagulation and UF had stably higher removal efficiencies of organic matters, whilst showed quite better fouling mitigation capabilities than the other methods. According to the analysis of total resistance changes in the NF membrane, coagulation could decrease the irreversible resistance to some extent, and improve the fouling recovery potential. Notwithstanding, the enhancement of nitrogen components by all pre-treatment methods were limited, indicating that further treatment would be necessary. This result herein was very useful to understand the NF process for drinking water treatment, as well to elevate the cost-effectiveness of NF application.