Southern Nevada Water Authority, Applied Research & Development Center, PO Box 99954, Las Vegas, NV 89193, USA.
Water Res. 2012 Feb 1;46(2):316-26. doi: 10.1016/j.watres.2011.10.021. Epub 2011 Oct 25.
An ozone and ozone/peroxide oxidation process was evaluated at pilot scale for trace organic contaminant (TOrC) mitigation and NDMA formation in both drinking water and water reuse applications. A reverse osmosis (RO) pilot was also evaluated as part of the water reuse treatment train. Ozone/peroxide showed lower electrical energy per order of removal (EEO) values for TOrCs in surface water treatment, but the addition of hydrogen peroxide increased EEO values during wastewater treatment. TOrC oxidation was correlated to changes in UV(254) absorbance and fluorescence offering a surrogate model for predicting contaminant removal. A decrease in N-nitrosodimethylamine (NDMA) formation potential (after chloramination) was observed after treatment with ozone and ozone/peroxide. However, during spiking experiments with surface water, ozone/peroxide achieved limited destruction of NDMA, while in wastewaters net direct formation of NDMA of 6-33 ng/L was observed after either ozone or ozone/peroxide treatment. Once formed during ozonation, NDMA passed through the subsequent RO membranes, which highlights the significance of the potential for direct NDMA formation during oxidation in reuse applications.
臭氧和臭氧/过氧化物氧化工艺在中试规模上进行了评估，用于去除饮用水和水再利用应用中的痕量有机污染物 (TOrC) 和 NDMA 的形成。反渗透 (RO) 中试也作为水再利用处理链的一部分进行了评估。在地表水的处理中，臭氧/过氧化物对 TOrC 的去除率的单位能耗 (EEO) 值较低，但在废水处理中添加过氧化氢会增加 EEO 值。TOrC 的氧化与 UV(254) 吸光度和荧光的变化相关，为预测污染物去除提供了替代模型。在用臭氧和臭氧/过氧化物处理后，观察到氯胺消毒后 N-亚硝基二甲胺 (NDMA) 形成潜力 (FP) 的降低。然而，在地表水的加标实验中，臭氧/过氧化物对 NDMA 的破坏有限，而在废水处理中，在用臭氧或臭氧/过氧化物处理后，观察到 NDMA 的净直接形成量为 6-33ng/L。在臭氧化过程中形成后，NDMA 会通过后续的 RO 膜，这突出表明在再利用应用中的氧化过程中直接形成 NDMA 的可能性非常重要。
