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Updated: Aug 4, 2025

Forming Micro-and Nano-Plastics from Agricultural Plastic Films for Employment in Fundamental Research Studies
Published on: July 27, 2022
The effects of microplastics and nanoplastics on nitrogen removal, extracellular polymeric substances and microbial
Hua Wang1, Cheng Qiu2, Shaochen Bian2
1School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China; Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China.
Abstract:
Wastewater treatment plants can be nanoplastics (NPs) and microplastics (MPs) sinks and sources. The effects of NPs and MPs on nitrogen removal and extracellular polymeric substances (EPS) during activated sludge process need further investigation. Results showed that polystyrene NPs (NPS) and 100 mg/L polystyrene MPs (MPS) decreased the specific nitrate reduction rate, resulting in nitrate accumulation. The negative effects on functional genes involved in denitrification (narG, napA, nirS and nosZ) were the main mechanism. NPS stimulated EPS secretion, but MPS inhibited it. NPS and MPS increased the ratio of protein to polysaccharide except for 10 mg/L MPS and changed the secondary structure of protein in EPS, affecting flocculation ability of activated sludge. The changes of microbial abundance in activated sludge could be the main factor to the alterations of EPS and nitrogen removal. These results may facilitate understanding the impacts of NPs and MPs on wastewater treatment processes.
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