School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
J Environ Sci (China). 2022 Jul;117:326-335. doi: 10.1016/j.jes.2022.05.029. Epub 2022 May 30.
Chlorine disinfection of saline wastewater effluents rich in bromide and iodide forms relatively toxic brominated and iodinated disinfection byproducts (DBPs). Ultrasonication is a relatively new water treatment technology, and it is less sensitive to suspended solids in wastewaters. In this study, we examined the effects of ultrasonication (in terms of reactor type and combination mode with chlorination) on the DBP formation and toxicity in chlorinated primary and secondary saline wastewater effluents. Compared with the chlorinated wastewater effluent samples without ultrasonication, ultrasonic horn pretreatment of the wastewater effluent samples reduced the total organic halogen (TOX) levels in chlorination by ∼30%, but ultrasonic bath pretreatment of the wastewater samples did not significantly change the TOX levels in chlorination, which might be attributed to the higher energy utilization and decomposition extent of organic DBP precursors in the ultrasonic horn reactor. Moreover, the TOX levels in the chlorinated samples with ultrasonic horn pretreatment (USH-chlorination), simultaneous treatment (chlorination+USH) and subsequent treatment (chlorination-USH) were also significantly reduced, with the maximum TOX reductions occurring in the samples with ultrasonic horn pretreatment. A toxicity index was calculated by weighting and summing the levels of total organic chlorine, total organic bromine and total organic iodine in each treated sample. The calculated toxicity index values of the chlorinated wastewater effluent samples followed a descending rank order of "chlorination" > "chlorination+USH" > "chlorination-USH" > "USH-chlorination", with the lowest toxicity occurring in the samples with ultrasonic horn pretreatment. Then, a developmental toxicity bioassay was conducted for each treated sample. The measured toxicity index values of the chlorinated wastewater samples followed the same descending rank order.
富含溴和碘的盐水废水经氯消毒会形成相对有毒的溴化和碘化消毒副产物（DBP）。超声处理是一种相对较新的水处理技术，对废水中的悬浮物不太敏感。在这项研究中，我们研究了超声处理（就反应器类型和与氯化结合的组合模式而言）对氯化一级和二级盐水废水处理厂中 DBP 形成和毒性的影响。与未经超声处理的氯化废水处理厂样品相比，废水处理厂样品的超声喇叭预处理将氯化过程中的总有机卤素（TOX）水平降低了约 30%，但废水样品的超声浴预处理并未显著改变氯化过程中的 TOX 水平，这可能是由于超声喇叭反应器中有机 DBP 前体的能量利用率和分解程度更高。此外，经超声喇叭预处理（USH-氯化）、同时处理（氯化+USH）和后续处理（氯化-USH）的氯化样品中的 TOX 水平也显著降低，其中超声喇叭预处理的样品中 TOX 降低幅度最大。通过加权求和处理后每个样品中总有机氯、总有机溴和总有机碘的水平，计算出毒性指数。氯化废水处理厂样品的计算毒性指数值按“氯化”>“氯化+USH”>“氯化-USH”>“USH-氯化”的顺序依次降低，其中超声喇叭预处理的样品毒性最低。然后，对每个处理后的样品进行发育毒性生物测定。氯化废水样品的实测毒性指数值也遵循相同的降序排列。
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