Selection of membrane for production of drinking water from surface and groundwater by nanofiltration

Abstract

The aim of the work was to select a nanofiltration membrane that would ensure effective simultaneous co-removal of pollutants present in surface and groundwater, including contaminants such as bisphenol A and PFAS compounds. Series of membrane filtrations was carried out using 12 commercial nanofiltration membranes (NFX, NFG, NF270, NF90, DK, DL, TS80, SB90, TS40, XN45, NPO30, NPO10) under various operating parameters. The conducted tests showed that among tested membranes the membrane most suitable for the production of drinking water from model waters is the NF90 membrane by Dow Filmtec. Regardless of the composition of the water, its pH and transmembrane pressure, the water produced using NF90 membrane each time met the legal requirements in terms of heavy metals (chromium total, silver, nickel, lead, arsenic), iron, manganese, sulfates, chlorides, fluorides, nitrates, sodium, PFAS, tetrachlorethylene, bisphenol A and KMnO4 index. In addition, tests carried out to verify the susceptibility of the produced water to the formation of disinfection by-products (DBP - ∑THM and halogenoacetic acids) showed that DBP concentrations in produced water did not exceed the values permitted by law.