Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
ERZ Entsorgung + Recycling Zürich, CH-8050, Zürich, Switzerland.
Water Res. 2017 Jun 1;116:76-85. doi: 10.1016/j.watres.2017.02.026. Epub 2017 Feb 14.
Wastewater treatment plants (WWTPs) are important point sources for micropollutants, which are harmful to freshwater organisms. Ozonation of wastewater is a powerful option to abate micropollutants, but may result in the formation of the potentially toxic oxidation by-product bromate in bromide-containing wastewaters. This study investigates options to reduce bromate formation during wastewater ozonation by (i) reducing the bromide concentration of the wastewater, (ii) lowering the ozone dose during wastewater treatment and (iii) adding hydrogen peroxide to limit the lifetime of ozone and quench the intermediates of the bromate formation pathway. Two examples demonstrate that a high share of bromide in wastewater can originate from single point sources (e.g., municipal waste incinerators or landfills). The identification of major point sources requires laborious sampling campaigns, but may facilitate the reduction of the bromide load significantly. To reduce the bromate formation by lowering the ozone dose interferes with the aim to abate micropollutants. Therefore, an additional treatment is necessary to ensure the elimination of micropollutants. Experiments at a pilot-plant illustrate that a combined treatment (ozone/powdered activated carbon) allows to eliminate micropollutants with low bromate yields. Furthermore, the addition of hydrogen peroxide was investigated at bench-scale. The bromate yields could be reduced by ∼50% and 65% for a hydrogen peroxide dose of 5 and 10 mg L, respectively. In conclusion, there are options to reduce the bromate formation during wastewater ozonation, however, they are not simple with sometimes limited efficiency.
污水处理厂（WWTP）是微污染物的重要点源，这些污染物对淡水生物有害。废水臭氧化是一种去除微污染物的有效方法，但可能导致含溴废水中潜在有毒的氧化副产物溴酸盐的形成。本研究通过（i）降低废水的溴化物浓度、（ii）降低废水处理中的臭氧剂量和（iii）添加过氧化氢来限制臭氧的寿命并淬灭溴酸盐形成途径的中间体，研究了减少废水臭氧化过程中溴酸盐形成的方法。两个实例表明，废水中的高溴化物含量可能来自单一的点源（例如，城市垃圾焚烧厂或垃圾填埋场）。主要点源的识别需要进行艰苦的采样活动，但可以显著减少溴化物负荷。通过降低臭氧剂量来减少溴酸盐的形成会干扰去除微污染物的目标。因此，需要额外的处理来确保微污染物的去除。中试厂的实验表明，联合处理（臭氧/粉末活性炭）可以在产生低溴酸盐产率的情况下去除微污染物。此外，还在实验室规模上研究了过氧化氢的添加。当过氧化氢剂量分别为 5 和 10mg/L 时，溴酸盐的产率可分别降低约 50%和 65%。总之，有一些方法可以减少废水臭氧化过程中溴酸盐的形成，但它们并不简单，有时效率有限。
