Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
Water Res. 2021 Oct 15;205:117667. doi: 10.1016/j.watres.2021.117667. Epub 2021 Sep 15.
Ferrate(VI) (Fe(VI)) can oxidize individual pollutants, but the pollutant oxidation does not necessarily result in toxicity reduction. Besides, Fe(VI) resultant Fe(III) particles has previously been used to remove heavy metals, but its influence on organic matter and toxicity of wastewater is unknown. This study investigated influence of Fe(VI) on the cytotoxicity and DNA double-strand break (DSB) effects of secondary effluents from wastewater treatment plants to Chinese hamster ovary cells. Adding 5.0 mg/L Fe(VI) as Fe reduced the cytotoxicity and genotoxicity of secondary effluents by 44%-71% and 40%-59%, respectively. The toxicity reduction could be explained by the alleviation of oxidative stress in cells when they were exposed to the Fe(VI)-treated organic matter. Oxidation and coagulation accounted for 60 and 40% of the reductions in cytotoxicity and genotoxicity, demonstrating that both oxidation and coagulation processes can play important roles in reducing toxicity. Molecular weight (MW)-distribution analysis showed that the oxidation process was favored for removing ultraviolet absorbance and fluorescence intensity of organic matter, while the coagulation process removed more dissolved organic carbon (DOC), especially the DOC of fractions with MW < 500 Da. Compared with ferric chloride, the Fe(VI) resultant Fe(III) showed better coagulation performance on organic matter, cytotoxicity and genotoxicity removal, because of the different particle sizes and crystalline structures. This study highlights the benefit of using Fe(VI) in advanced treatment as Fe(VI) reduced the overall toxicity of secondary effluents.
高铁酸盐（VI）（Fe（VI））可以氧化个别污染物，但污染物的氧化不一定会降低毒性。此外，Fe（VI）生成的 Fe（III）颗粒以前曾被用于去除重金属，但它对有机物和废水毒性的影响尚不清楚。本研究调查了 Fe（VI）对污水处理厂二级出水对中国仓鼠卵巢细胞的细胞毒性和 DNA 双链断裂（DSB）效应的影响。添加 5.0mg/L 的 Fe（VI）作为 Fe 可将二级出水的细胞毒性和遗传毒性分别降低 44%-71%和 40%-59%。毒性降低可以用细胞暴露于 Fe（VI）处理的有机物时氧化应激的缓解来解释。氧化和混凝分别占细胞毒性和遗传毒性降低的 60%和 40%，表明氧化和混凝过程都可以在降低毒性方面发挥重要作用。分子量（MW）分布分析表明，氧化过程有利于去除有机物的紫外吸光度和荧光强度，而混凝过程去除更多的溶解有机碳（DOC），特别是 MW<500Da 的 DOC 分数。与三氯化铁相比，Fe（VI）生成的 Fe（III）在去除有机物、细胞毒性和遗传毒性方面表现出更好的混凝性能，这是因为其颗粒大小和晶体结构不同。本研究强调了在高级处理中使用 Fe（VI）的好处，因为 Fe（VI）降低了二级出水的整体毒性。
