Nitrogen removal performance of bioretention cells under polyethylene (PE) microplastic stress

Jiajia Zhou; Zinuo Zhang; Jiaqing Xiong; WeiPeng Shi; Lipeng Liang; Fanghong Zhang; Fei Zhang

doi:10.1016/j.envpol.2023.122655

Nitrogen removal performance of bioretention cells under polyethylene (PE) microplastic stress

Environ Pollut. 2023 Dec 1:338:122655. doi: 10.1016/j.envpol.2023.122655. Epub 2023 Sep 29.

Authors

Jiajia Zhou¹, Zinuo Zhang¹, Jiaqing Xiong², WeiPeng Shi¹, Lipeng Liang¹, Fanghong Zhang³, Fei Zhang⁴

Affiliations

¹ Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China.
² Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China. Electronic address: xiongjiaqing@xauat.edu.cn.
³ Qinghai Provincial Civil Air Defense Engineering Design and Research Institute Co., Ltd, China.
⁴ Wuhan Municipal Engineering Design & Research Institute Co., Ltd, China.

PMID: 37778494
DOI: 10.1016/j.envpol.2023.122655

Abstract

The use of bioretention cells as a stormwater control measure allows stormwater runoff to be collected and filtered, effectively removing microplastics and other pollutants from stormwater. This study investigated the effect of polyethylene microplastics (PE-MPs) retention on the bioretention cell, in terms of denitrification performance and microbial community structure. Four PE-MP exposures were compared at different concentrations of 0, 250, 500 and 1000 mg/L under alternating dry and wet period conditions. Results showed that the removal efficiency reduced by 14.99%, 28.37% and 18.59% with PE-MP concentrations of 250, 500 and 1000 mg/L. The NO₃^--N removal efficiency increased by 36.19%, 20.19% and 35.39%. After 8 days of dry conditions, the NO₃^--N removal efficiencies of the bioretention cells were reduced by 36.66%, 46.86% and 31.11% compared to those after 2 days of dry conditions. Microbial sequencing results indicated that the accumulation of PE-MPs changed the microbial community structure within the bioretention cell filler material, promoting the growth of bacteria such as Actinobacteria, Bacteroidetes and Firmicutes. Furthermore, PE-MPs reduced the relative abundance of nitrifying bacteria (e.g. Nitrospira) within the bioretention cell and promoted denitrifying bacteria (e.g. Dechloromonas and Hydrogenophaga), along with numerous other genera such as Azotobacter and Nocardia.

Keywords: Bacterial community; Bioretention systems; Nitrogen transformation; Plastics.

MeSH terms

Bacteria
Denitrification*
Microplastics
Nitrogen
Plastics*
Polyethylene
Rain

Substances

Plastics
Polyethylene
Microplastics
Nitrogen