Influence of NF on distribution system biostability

In a 12‐month study, nanofiltration achieved high percentages of BDOC removal but was less effective in reducing AOC concentrations. When biodegradable organic matter is not removed during water treatment, bacteria may proliferate in the distribution system. This bacterial growth can deteriorate water quality, accelerate pipe corrosion, and potentially increase the incidence of bacteriological diseases. This project's main objective was to collect and analyze full‐scale system data on long‐term results of nanofiltration (NF) with respect to its effect on bacterial regrowth potential as quantified by assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC). One of the major observations over the sampling period was that NF had a strong effect on the BDOC concentration of the treated water. In contrast, NF did not reject the major fraction of AOC, which leaves NF's effect on biostability open to question.