Zhou Chun-Shuang, Wu Ji-Wen, Ma Wan-Li, Liu Bing-Feng, Xing De-Feng, Yang Shan-Shan, Cao Guang-Li
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
J Hazard Mater. 2022 Jun 15;432:128715. doi: 10.1016/j.jhazmat.2022.128715. Epub 2022 Mar 15.
Microplastics (MPs) and nanoplastics (NPs), as emerging pollutants, are frequently detected in wastewater treatment plants. However, studies comparing the effects of MPs versus NPs on nitrogen removal by activated sludge are rarely reported. Here, the responses of nitrogen removal performance, microbial community and functional genes to MPs and NPs in sequencing batch reactors were investigated. Results revealed that MPs (10 and 1000 μg/L) had no effects on nitrogen removal. While upon exposure to NPs, although low concentration (10 μg/L) of NPs showed no remarkable influence on nitrogen removal, high level (1000 μg/L) of NPs decreased NH-N removal efficiency by 24.48% and caused accumulation of NO-N and NO-N. These inhibitory probably due to the acute toxicity of NPs to activated sludge, which was reflected by the increasing reactive oxygen species generation and lactate dehydrogenase release. The toxic effects of NPs further declined the relative abundance of nitrifiers (e.g., Nitrospira) and denitrifiers (e.g., Dechloromonas). These negative effects, accompanied by a decrease in abundance of amoA and nxrA genes related to nitrification (30.01% and 65.24% of control) and narG, nirK and nirS genes associated with denitrification (78.59%, 61.39%, and 86.17% of control), directly illustrated the attenuate phenomenon observed in nitrogen removal.
微塑料（MPs）和纳米塑料（NPs）作为新兴污染物，在污水处理厂中经常被检测到。然而，比较 MPs 和 NPs 对活性污泥脱氮效果影响的研究报道很少。在此，研究了序批式反应器中脱氮性能、微生物群落和功能基因对 MPs 和 NPs 的响应。结果表明，MPs（10 和 1000 μg/L）对脱氮没有影响。而暴露于 NPs 时，虽然低浓度（10 μg/L）的 NPs 对脱氮没有显著影响，但高浓度（1000 μg/L）的 NPs 使 NH-N 去除效率降低了 24.48%，并导致 NO-N 和 NO-N 的积累。这些抑制作用可能是由于 NPs 对活性污泥的急性毒性，这通过活性氧生成增加和乳酸脱氢酶释放得以体现。NPs 的毒性作用进一步降低了硝化菌（如硝化螺菌属）和反硝化菌（如脱氯单胞菌属）的相对丰度。这些负面影响伴随着与硝化作用相关的 amoA 和 nxrA 基因丰度的降低（分别为对照的 30.01%和 65.24%）以及与反硝化作用相关的 narG、nirK 和 nirS 基因丰度的降低（分别为对照的 78.59%、61.39%和 86.17%），直接说明了在脱氮过程中观察到的减弱现象。
