ABSTRACT
In this paper, we proposed a strategy for the establishment of an aerobic granular sludge (AGS) system for simultaneous nitrogen and Pb(II) removal from inorganic wastewater. AGS was stored in lead nitrate solution to select functional bacteria resistant to lead poison, and then an AGS system for ammonia nitrogen (180-270 mg/L) and Pb(II) (15-30 mg/L) removal was established based on carbon dosing and a two-stage oxic/anoxic operational mode. After storage for 40 days, the stability of AGS decreased because specific oxygen uptake rate, nitrification rate and abundance of Nitrosomonas decreased to different degrees compared with those before storage. During the first 70 days of the recovery process, AGS in R1 (the blank reactor) and R2 (the control reactor) both experienced a first breakage and then regranulation process. The main properties of AGS in reactors R1 and R2 tended to be stable after days 106 and 117, respectively, but the structure of steady-state AGS in R2 was more compact. The total inorganic nitrogen (TIN) in effluent from R1 and R2 basically remained below 25 mg/L after days 98 and 90, respectively. The Pb(II) concentration in effluent from R2 was always below 0.3 mg/L. On day 140, the relative abundance of Nitrosomonas in R2 (6.17%) was significantly lower than that in R1 (12.15%), whereas the relative abundance of denitrifying bacteria was significantly higher than that in R1 (62.44% and 46.79%). The system removed 1 kg of influent TIN only consuming approximately 1.85 kg of carbon source, demonstrating clear advantages in energy savings.
Acknowledgement
This research was supported by National Natural Science Foundation of China (No. 52060007), Science and Technology program of Education Department of Jiangxi Province (GJJ190502), The Program of Qingjiang Excellent Young Talents, Jiangxi University of Science and Technology (JXUSTQJYX2020008), and the Opening Project of Henan Province Key Laboratory of Water Pollution Control and Rehabilitation Technology (CJSP2021004).
Disclosure statement
No potential conflict of interest was reported by the authors.
Data Availability Statement
The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.