NDMA Precursor Control Strategies for Direct Potable Reuse

This project investigated the occurrence, possible sources, and fate of nitrosamines and their precursors through wastewater collection, a Modified Ludzack-Ettinger activated sludge treatment process, and two pilot advanced treatment trains. Domestic sources were found to dominate over industrial sources in total loading of nitrosodimethylamine (NDMA) and NDMA precursors to the sewer system. This is also the first reported detection of N-nitrosomorpholine in domestic sources. The impact of varying solids retention times during activated sludge treatment of NDMA and its precursors did not yield conclusive results because it was discovered that NDMA was formed as an artefact from US EPA Method 521 in nitrified secondary effluent samples. The removal and reformation of NDMA and its precursors was evaluated across two different pilot advanced treatment trains. This research provides a holistic understanding of NDMA and its precursors from collection system to treated effluent, ultimately supporting DBP control efforts in wastewater reuse.