Removal of N-nitrosodimethylamine (NDMA) Precursors During Drinking Water Treatment

Technologies that are effective for natural organic matter and contaminant removal (i.e., coagulation) have been largely unsuccessful for the removal of N-nitrosodimethylamine (NDMA) and its precursors. A growing number of drinking water treatment plants that use chloramines for secondary disinfection have reported NDMA in finished water due to the reaction of chloramines with small nitrogen-containing molecules such as dimethylamine (DMA). This research examined the impact of pilot-scale biofilter operation on NDMA formation potential. The results of this study suggest that the use of biofiltration provides removal of NDMA precursors, regardless of filter operation. Ranitidine was also spiked at pilot scale to evaluate the ability of biofilters to remove a specific NDMA precursor and to confirm results using ambient influent waters. No significant difference (α = 0.05) was found in terms of NDMA FP removal due to filter operation strategy or empty bed contact time (EBCT).M.A.S