Up until recently, most of the focus on Disinfection By-Products (DBPs) has been placed on Trihalomethanes (THMs) and Haloacetic Acids (HAAs). However, DBP studies indicate that more than half of the percentage of total organic halides have yet to be identified. So what other DBPs are being formed? William Mitch has set out to answer this question, and believes an important contributor may be nitrogen containing DBPs.
More specifically, a group called N-nitrosamines, carcinogens also found in hot dogs and beer, have been a particular focus. N-nitrosamines are byproducts from the chlorination of dissolved organic nitrogen precursors, and are especially prevalent when chloramines are used for disinfection. In addition, treated wastewaters yield even higher levels of these nitrogen precursors upon chlorination, up to almost an order of magnitude in scale. For this reason, N-nitrosamines are even more likely to be formed in drinking water supplies that have been impacted by wastewater discharge.
The focus of Dr. Mitch's seminar will be on the chemistry behind the formation of these harmful by-products, his attempt to label key precursors, and how their formation can be prevented. In addition, specific focus will be placed on N-nitrosodimethylamine (NDMA), and its role as a drinking water contaminant. Ultimately, the goal of Dr. Mitch's research is to provide utilities with ideas for treatment technologies that will remove key precursors, thereby aiding in the reduction of these chemicals in finished waters.For more information, including the most recently published papers, see Dr. Mitch's web site.