Department of Chemical Engineering, Lund University, PO Box 124, SE-221 00 Lund, Sweden.
Department of Chemical Engineering, Lund University, PO Box 124, SE-221 00 Lund, Sweden; Sweden Water Research AB, Ideon Science Park, Scheelevägen 15, SE-223 70 Lund, Sweden.
Sci Total Environ. 2022 Oct 1;841:156694. doi: 10.1016/j.scitotenv.2022.156694. Epub 2022 Jun 14.
Ozonation of wastewater can reduce the release of organic micropollutants, but may result in the formation of undesirable by-products, such as bromate from bromide. Bromide is one of the most abundant ions in seawater, the primary precursor of bromate during ozonation, and the end product in microbial bromate reduction. Investigations were carried out to compare the concentration of bromide in wastewater in coastal and non-coastal catchment areas, to monitor bromate formation during ozonation, and to assess the potential for subsequent bromate reduction with denitrifying carriers. Higher bromide concentrations were systematically observed in wastewater from coastal catchment areas (0.2-2 mg Br/L) than in wastewater from non-coastal areas (0.06-0.2 mg Br/L), resulting in elevated formation of bromate during ozonation. Subsequent investigations of bromate reduction in contact with denitrifying carriers from two full-scale moving bed biofilm reactors (MBBRs) showed that 80 % of the bromate formed during ozonation could be reduced to bromide in 60 min with first-order rate constants of 0.3-0.8 L/(g·h). Flow-through experiments with denitrifying carriers also showed that combined reduction of bromate and nitrate could be achieved below a concentration of 2 mg NO-N/L. These findings indicate that bromide-rich wastewater is more likely to be of concern when using ozonation in coastal than in non-coastal areas, and that bromate and nitrate reduction can be combined in a single biofilm reactor.
废水的臭氧氧化可以减少有机微量污染物的释放，但可能导致不良副产物的形成，如溴酸盐来自溴化物。溴化物是海水中最丰富的离子之一，是臭氧氧化过程中溴酸盐的主要前体，也是微生物溴酸盐还原的最终产物。进行了研究，以比较沿海和非沿海集水区废水中的溴化物浓度，监测臭氧氧化过程中溴酸盐的形成，并评估使用反硝化载体进行随后的溴酸盐还原的潜力。系统地观察到沿海集水区废水中的溴化物浓度较高（0.2-2mgBr/L），而非沿海集水区废水中的溴化物浓度较低（0.06-0.2mgBr/L），导致臭氧氧化过程中溴酸盐的形成增加。随后在两个全规模移动床生物膜反应器（MBBR）的反硝化载体上进行的溴酸盐还原研究表明，臭氧氧化过程中形成的溴酸盐中有 80%可以在 60 分钟内还原为溴化物，一级速率常数为 0.3-0.8L/（g·h）。反硝化载体的流动实验还表明，在 2mgNO-N/L 以下可以同时实现溴酸盐和硝酸盐的还原。这些发现表明，在沿海地区使用臭氧氧化时，富溴化物废水更有可能引起关注，并且溴酸盐和硝酸盐还原可以在单个生物膜反应器中结合进行。
