N-Nitrosodimethylamine (NDMA), an important contaminant for potable reuse of municipal wastewater, forms from reactions of dichloramine and amine precursors. Injection of concentrated free chlorine stock solutions into wastewaters containing low levels of ammonia can promote NDMA formation because the high chlorine:ammonia ratio at the point of chlorine injection fosters dichloramine formation during mixing. This study combined chemical kinetic modeling, laboratory mixing studies using deionized water and authentic wastewater effluents, and a pilot-scale disinfectant contactor at a wastewater reuse facility to demonstrate that the distribution of the injection of concentrated hypochlorite stock solutions can reduce the level of NDMA formation by ≤50% compared to injection at a single location. Modeling and deionized water experiments indicated that this reduction was associated with a reduction in the level of dichloramine formation.

中文翻译：

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分布式氯气注入，以最大程度地减少废水氯化过程中的NDMA形成

ñ-亚硝基二甲胺（NDMA）是市政污水可饮用水回用的重要污染物，由二氯胺和胺前体的反应形成。将高浓度的游离氯储备溶液注入含有少量氨的废水中会促进NDMA的形成，因为在注入氯时高的氯：氨比会促进混合过程中二氯胺的形成。这项研究结合了化学动力学建模，使用去离子水和纯正废水的实验室混合研究以及废水回用设施中的中试规模消毒剂接触器，以证明浓次氯酸盐储备溶液的进样分布可以减少NDMA的形成。与单一位置的注射量相比，降低了≤50％。