Reduction of Disinfection By‐Product Precursors in Reservoir Water by Submerged Nanofiltration Membrane

ABSTRACT In the disinfection process in conventional treatment systems, the widely used chemical is chlorine, which is readily available and inexpensive. When water sources contain organic substances, they often react with disinfectants to form disinfection by‐products. Trihalomethane is one of the disinfection by‐products that are classified as carcinogens. This study aims to evaluate the removal of disinfection by‐product precursors in reservoir water by submerged nanofiltration membrane and compare the efficiency with conventional water treatment processes regarding natural organic matter removal. Raw (feed) water, permeate, and concentrate water were analyzed, including ultraviolet absorbance at 254 nm, dissolved organic carbon, fluorescence excitation‐emission matrices, temperature, pH, electrical conductivity, turbidity, and trihalomethane formation potential. The membranes supplied by DuPont were subjected to scanning electron microscopy analysis to determine the fouling characteristics. The results showed that the membrane had a smooth surface. In addition, the NF270 membrane effectively reduced turbidity, electrical conductivity, total dissolved solid, ultraviolet absorbance at 254 nm, dissolved organic carbon, and trihalomethane formation potential by 94%–99%, 36%–65%, 36%–64%, 50%–89%, 47%–81%, and 68.48%, respectively. Moreover, transmembrane pressure increased slightly, indicating that the system was stable in operation even if the water source quality was different. A submerged flat‐sheet membrane module is used to treat surface water directly at low permeate flux conditions. The membrane also has the advantage of superior ion removal over conventional treatment.