Membrane fouling characteristics and cleaning strategies for rural decentralized nanofiltration drinking water...

Groundwater is an important source of drinking water in rural areas. In this study, the performance of water purificat ion in a rural water station equipped with nanofiltration (NF) membranes based groundwater source was investigated, as well as the contamination morphology, foulant composition and distribution characteristics of NF membrane. Results showed that significant differences of membrane foulants were observed in different sections of NF membrane. The inlet and middle sections were dominated by organic foulants and exhibited a high abundance of microbial communities associated with organic matter metabolism, and the outlet section was dominated by inorganic foulants and showed an elevated abundance of microorganisms such as Dechloromonas, norank_f_Desulfuromonadaceae, Ferribacterium, Dietzia, Mycobacterium, and Bradyrhizobium. Inorganic fouling accounted for 39.32% of the total resistance and was the main factor contributing to the decrease in membrane flux. Based on the flux recovery after membrane cleaning, the flux recovery obtained by the combination of " acid followed by alkaline " is 1.59 times higher than the flux of the contaminated membrane. This study can support the operation and maintenance of NF drinking water stations to extend the service life of membranes.