Responses of nitrogen removal under microplastics versus nanoplastics stress in SBR: Toxicity, microbial community and functional genes

Chun-Shuang Zhou; Ji-Wen Wu; Wan-Li Ma; Bing-Feng Liu; De-Feng Xing; Shan-Shan Yang; Guang-Li Cao

doi:10.1016/j.jhazmat.2022.128715

Responses of nitrogen removal under microplastics versus nanoplastics stress in SBR: Toxicity, microbial community and functional genes

J Hazard Mater. 2022 Jun 15:432:128715. doi: 10.1016/j.jhazmat.2022.128715. Epub 2022 Mar 15.

Authors

Chun-Shuang Zhou¹, Ji-Wen Wu¹, Wan-Li Ma¹, Bing-Feng Liu¹, De-Feng Xing¹, Shan-Shan Yang¹, Guang-Li Cao²

Affiliations

¹ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
² State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: caogl@hit.edu.cn.

PMID: 35305418
DOI: 10.1016/j.jhazmat.2022.128715

Abstract

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 NH₄⁺-N removal efficiency by 24.48% and caused accumulation of NO₃^--N and NO₂^--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.

Keywords: Microbial community; Microplastics; Nanoplastics; Nitrogen removal; SBR.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bioreactors
Denitrification
Microbiota* / genetics
Microplastics* / toxicity
Nitrification
Nitrogen / analysis
Plastics
Sewage

Substances

Microplastics
Plastics
Sewage
Nitrogen