Towards a better understanding of the anaerobic/oxic/anoxic-aerobic granular sludge process (AOA-AGS) for simultaneous low-strength wastewater treatment and in situ sludge reduction from ambient to winter temperatures

Qiulai He; Xiaohui Yan; Hongyu Wang; Yaning Ji; Jinfeng Li; Liang Liu; Peng Bi; Peng Xu; Baokun Xu; Jingwei Ma

doi:10.1016/j.envres.2023.116822

Towards a better understanding of the anaerobic/oxic/anoxic-aerobic granular sludge process (AOA-AGS) for simultaneous low-strength wastewater treatment and in situ sludge reduction from ambient to winter temperatures

Environ Res. 2023 Nov 1;236(Pt 2):116822. doi: 10.1016/j.envres.2023.116822. Epub 2023 Aug 2.

Authors

Qiulai He¹, Xiaohui Yan¹, Hongyu Wang², Yaning Ji¹, Jinfeng Li¹, Liang Liu¹, Peng Bi¹, Peng Xu¹, Baokun Xu³, Jingwei Ma⁴

Affiliations

¹ Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China.
² School of Civil Engineering, Wuhan University, Wuhan, 430082, China.
³ Agricultural Water Conservancy Department, Changjiang River Scientific Research Institute, Wuhan, 430010, China.
⁴ Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China. Electronic address: jma@hnu.edu.cn.

PMID: 37541415
DOI: 10.1016/j.envres.2023.116822

Abstract

The new anaerobic/oxic/anoxic-aerobic granular sludge (AOA-AGS) merits the advantages of effective carbon utilization and low-carbon treatment. However, low temperature poses stressing concerns and the resisting mechanism remains much unknown. Herein, an AOA-AGS process was configured for simultaneous nitrification, denitrification and phosphorus removal (SNDPR) with low-strength wastewater from ambient (>15 °C) to winter temperatures (<15 °C). Results showed that simultaneously advanced nutrients removal, and dramatic in situ sludge reduction (Y_obs of 0.093 g MLSS/g COD) were gained regardless of seasonally decreasing temperatures. Winter temperatures even amplified Candidatus Competibacter predominating from 20.11% to 34.74%, which laid the core basis for endogenous denitrification, sludge minimization and temperature resistance. A removal model was thus proposed given the observed functional groups, and doubts were also raised for future investigations. This study would aid a better understanding on the microbial ecology and engineering aspects of the new AOA-AGS process treating low-strength wastewater at low temperatures.

Keywords: Aerobic granular sludge; Anaerobic/oxic/anoxic; Candidatus competibacter; In situ sludge reduction; Low temperature.