Protective strategies and self-adaptive responses of algal-bacterial granular sludge system for the treatment of high-salinity N-Methylpyrrolidone wastewater

Xiaoyu Zhang; Shuaishuai Guo; Yan Xia; Xinying Hou; Jinyou Shen; Xinbai Jiang

doi:10.1016/j.jhazmat.2025.139043

Protective strategies and self-adaptive responses of algal-bacterial granular sludge system for the treatment of high-salinity N-Methylpyrrolidone wastewater

J Hazard Mater. 2025 Jun 24:495:139043. doi: 10.1016/j.jhazmat.2025.139043. Online ahead of print.

Authors

Xiaoyu Zhang¹, Shuaishuai Guo¹, Yan Xia¹, Xinying Hou¹, Jinyou Shen², Xinbai Jiang³

Affiliations

¹ Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
² Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Engineering Research Centre of Chemical Pollution Control, Ministry of Education, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
³ Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Engineering Research Centre of Chemical Pollution Control, Ministry of Education, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. Electronic address: xinbai_jiang@njust.edu.cn.

PMID: 40570620
DOI: 10.1016/j.jhazmat.2025.139043

Abstract

Algal-bacterial granular sludge (ABGS) system has been widely concerned due to its advantages in reducing carbon emissions and energy consumption for wastewater treatment. Nevertheless, in high salinity wastewater treatment, high salinity would cause inhibition to microbial activity by triggering cell dehydration and reducing enzyme activity. This study proposed innovative insights into the improved salinity resistance in ABGS system for enhancing NMP and nitrogen removal at high salinity environment. Under 2 % salinity stress and 200 mg·L^-1·d^-1 NMP loading rate, the NMP removal efficiency in ABGS system reached 80.9 ± 5.6 %, as compared with that in anaerobic sludge (AS) system was 56.7 ± 9.6 %. Extracellular polymeric substances (EPS) secretion in ABGS was significantly stimulated, and polysaccharide played important roles for defending salinity stress. In addition, enhanced NMP removal and EPS secretion in ABGS system were revealed at genetic levels. As for microbial community dynamics, functional microorganism for NMP and nitrogen removal such as Pseudomonas, Lentimicrobium, and Paracoccus were significantly enriched in ABGS system, while salt-tolerant microorganism such as Fusibacter was not enriched. The ABGS system developed by assembling Chlorella into AS possessed EPS protection layer and self-adaption capacity, which was first proposed as a novel salinity resistance mechanism in ABGS system.

Keywords: Algal-bacterial granular sludge; Extracellular polymeric substances secretion; N-Methylpyrrolidone; Salinity resistance; Self-adaption.