Long-term exposure to nanoplastics reshapes the microbial interaction network of activated sludge

Daying Chen; Zizhang Wei; Zhimin Wang; Yongkui Yang; Liang Chen; Xiaohui Wang; Lin Zhao

doi:10.1016/j.envpol.2022.120205

Long-term exposure to nanoplastics reshapes the microbial interaction network of activated sludge

Environ Pollut. 2022 Dec 1:314:120205. doi: 10.1016/j.envpol.2022.120205. Epub 2022 Sep 19.

Authors

Daying Chen¹, Zizhang Wei², Zhimin Wang³, Yongkui Yang⁴, Liang Chen⁵, Xiaohui Wang⁶, Lin Zhao⁷

Affiliations

¹ School of Environmental Science and Engineering, Tianjin University, Tianjin, 300384, China; Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
² Tianjin Academy of Eco-Environmental Sciences, Tianjin, 300191, China.
³ Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China; Beijing Drainage Group Co., LTD, Beijing, 100061, China.
⁴ School of Environmental Science and Engineering, Tianjin University, Tianjin, 300384, China.
⁵ School of Civil Engineering, Tianjin University, Tianjin, 300384, China.
⁶ Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
⁷ School of Environmental Science and Engineering, Tianjin University, Tianjin, 300384, China. Electronic address: zhaolin@tju.edu.cn.

PMID: 36210595
DOI: 10.1016/j.envpol.2022.120205

Abstract

Wastewater treatment plants have been identified as an important gathering spot for nanoplastics, possibly having unintended impacts on important biological nutrient removal processes. The underlying effects of long-term exposure of activated sludge to nanoplastics on nutrient removal and the mechanisms involved remain unclear. This study investigated the effect of polystyrene nanoplastics (Nano-PS) on the treatment performance and microbial community structure, and network in activated sludge. The results indicate that 1000 μg/L Nano-PS had chronic negative effects on the treatment performance in a continuous test over 140 days. Nano-PS had no significant impact in the earlier stages (0-50 days). However, as exposure time increased, the removal efficiencies of chemical oxygen demand, total phosphorous, and total nitrogen (TN) decreased by 2.7, 33.2, and 23.5%, respectively, in the later stages (87-132 days). These adverse impacts further manifested as a change in the topological characteristics, forming a smaller scale, lower complexity, and weaker transfer efficiency of the microbial network. Moreover, the scale and complexity of subnetwork-nitrogen removal bacteria and subnetwork-nitrifier were inhibited, leading to an increase in the effluent TN and NH₄⁺-N. The decreased modules and connectors (keystone taxa) likely caused the deterioration of treatment performance and functional diversity, which was consistent with the change in PICRUSt results. Less competition, denser nodes, and more complex module structures were induced as a strategy to mediate the long-term stress of nano-PS. To our knowledge, this is the first attempt to explore the long-term effects of nano-PS on the microbial interaction network of activated sludge, laying an experimental foundation for reducing the risks associated with nanoplastics.

Keywords: Activated sludge; Long-term exposure; Microbial community; Microbial interaction; Polystyrene nanoplastic.

MeSH terms

Bioreactors / microbiology
Microbial Interactions
Microplastics*
Nitrogen / analysis
Nitrogen / toxicity
Polystyrenes
Sewage* / chemistry
Waste Disposal, Fluid / methods

Substances

Sewage
Microplastics
Polystyrenes
Nitrogen