Regulating organic loading to mitigate the impact of microplastics on nitrogen removal and microbial communities in SBR systems

IF 6.7 2区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of water process engineering Pub Date : 2025-05-01 DOI:10.1016/j.jwpe.2025.107800

Yi Yang , Lin Luo , Jian Zhu , Kai Deng , Changjun Li , Ying Zhang , Zhongxiang He , Pofei Wang , Hua Peng

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Abstract

The organic loading rate (OLR) is a key factor influencing activated sludge formation, while microplastics (MPs) have been shown to impact activated sludge performance and microbial community structure. However, the differential effects of MPs on nitrogen removal and microbial communities at varying OLRs remain unclear. This study investigates the effects of polyethylene microplastics (PE-MPs, the entire text will be abbreviated as MPs) on nitrogen removal efficiency and microbial community dynamics under different OLR conditions. Results demonstrate that at low OLR (0.05–0.10 kg BOD₅/ (kg MLSS·d)), MPs significantly reduced nitrogen removal efficiency, while this effect was less pronounced at normal OLR conditions (0.10–0.20 kg BOD₅/ (kg MLSS·d)), where nitrogen removal was maintained at approximately 83 % and effluent total nitrogen concentration was maintained at 7.37 mg/L, meeting the Class I effluent standards. This phenomenon could be attributed to two primary factors: (1) inhibition of extracellular polymeric substances (EPS) formation, with decreased release of protein (PRO) and polysaccharide (PSR) negatively affecting system stability and nitrification; and (2) nutrient scarcity, which led to the proliferation of heterotrophic bacteria that competed for resources and occupied space, thereby impacting the nitrifying microbial community (AOB, NOB, and NIRS). These results suggest that optimizing the influent OLR to 0.10–0.20 kg BOD₅/ (kg MLSS·d)) can help to mitigate the negative impacts of MPs in wastewater treatment systems.

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调节有机负荷以减轻微塑料对SBR系统中氮去除和微生物群落的影响

有机负荷率（OLR）是影响活性污泥形成的关键因素，而微塑料（MPs）已被证明会影响活性污泥的性能和微生物群落结构。然而，在不同的olr下，MPs对氮去除和微生物群落的差异影响尚不清楚。本研究探讨了聚乙烯微塑料（PE-MPs，全文将缩写为MPs）在不同OLR条件下对脱氮效率和微生物群落动态的影响。结果表明，在低OLR （0.05-0.10 kg BOD₅/ (kg MLSS·d)）下，MPs显着降低了氮的去除效率，而在正常OLR条件下（0.10-0.20 kg BOD₅/ (kg MLSS·d)），其中氮的去除率保持在约83%，出水总氮浓度保持在7.37 mg/L，符合I类出水标准。这一现象可归因于两个主要因素：(1)细胞外聚合物质（EPS）的形成受到抑制，蛋白质（PRO）和多糖（PSR）的释放减少，对系统稳定性和硝化作用产生负面影响；(2)营养物稀缺，导致异养菌大量繁殖，争夺资源和占用空间，从而影响硝化微生物群落（AOB、NOB和NIRS）。这些结果表明，将进水OLR优化到0.10-0.20 kg BOD₅/ (kg MLSS·d))可以帮助减轻MPs在废水处理系统中的负面影响。

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来源期刊

Journal of water process engineering Biochemistry, Genetics and Molecular Biology-Biotechnology

CiteScore

10.70

自引率

8.60%

发文量

846

审稿时长

24 days

期刊介绍： The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies