The formation and evolution of aerobic granular sludge (AGS) developed in a sequential batch reactor (SBR) were evaluated to understand the effect of influential operating parameters on its morphology, stability, and removal performance while treating industrial/municipal wastewater. After 18 days of operation (stage I), mature granules were identified in the reactor, and in 25 days, the AGS system reached a stable operation. The chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) were affected by the applied operating variations (from stages II to VII). Until day 48 (stage III), the aerobic granules did not show relevant changes in shape and stability. During this stage, the AGS system achieved high removal efficiencies of COD (97.7%) and TKN (86.2%) and a sludge volume index (SVI) of 65 ± 6.7 mL/g-total suspended solids. From stage IV until the end of the reactor operation, partial disintegration and rupture occurred in the system, but granules did not completely disintegrate. Specifically, a volumetric exchange ratio (VER) of >67% and an aeration rate (AR) of <2.5 L/min promoted the compactness and the structural integrity of AGS. The principal component analysis corroborated that the rise in the VER is an effective strategy for improving AGS stability and organic pollutant removal.
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http://dx.doi.org/10.2166/wst.2023.121 | DOI Listing |
J Environ Manage
December 2024
Department of Environmental Science and Engineering, Zhejiang Ocean University, No.1 Haida South Road, Zhoushan, 316022, PR China; Zhejiang Provincial Key Laboratory of Petrochemical Environmental Pollution Control, Zhoushan, 316022, PR China. Electronic address:
In order to study the resistance mechanisms of biofilm and granular sludge to various dissolved oxygen (DO) exposures in anaerobic ammonium oxidation (anammox) process, a biofilm - granular sludge anammox reactor was established and operated. Experimental results showed that DO levels of ≤0.41 mg L hardly affected the total nitrogen removal efficiency (TNRE).
View Article and Find Full Text PDFEnviron Res
December 2024
School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China. Electronic address:
Microbial loss significantly affects wastewater treatment efficiency. This study simulated the inoculation area of a self-developed biological doubling reactor (BDR) to evaluate the retention efficiency of seven different fillers for aerobic denitrifying bacteria. Over 90 days of continuous operation, the porous filler R3 demonstrated excellent performance, with OD values consistently exceeding 1.
View Article and Find Full Text PDFEnviron Res
December 2024
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, People's Republic of China. Electronic address:
Diffusible signal factor (DSF)-c-di-GMP-mediated strategies have been proposed as an effective regulatory approach for signal molecules in aerobic granular sludge (AGS). The increase in temperature from low to normal levels had a significant impact on AGS stability. In this study, two reactors were established to investigate the effects of different temperature rise modes (abrupt or gradual) on AGS stability.
View Article and Find Full Text PDFJ Environ Manage
December 2024
College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China.
With the widespread use of typical antibiotics such as sulfamethazine (SMT), it leads to their accumulation in the environment, increasing the risk of the spread of antibiotic resistance genes (ARGs). Aerobic granular sludge (AGS) has shown great potential in treating antibiotic wastewater. However, the long cultivation period of AGS, the easy disintegration of particles and the poor stability of degradation efficiency for highly concentrated antibiotic wastewater are still urgent problems that need to be solved, and it is important to explore the migration and changes of ARGs and microbial diversity in AGS systems.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Applied and Environmental Chemistry, University of Szeged, Szeged, Hungary.
Currently, the increasing use of nickel metal-organic frameworks (Ni-MOF) and nickel oxide nanoparticles (NiO NPs) has raised concerns regarding their potential environmental impact on wastewater treatment systems. Herein, the responses of aerobic granular sludge (AGS) and algal-bacterial aerobic granular sludge (AB-AGS) to Ni-MOF and NiO NPs were investigated. The results showed that Ni-MOF concentrations of 50, 100, and 200 mg/L significantly reduced nutrient removal in both systems, particularly affecting ammonia, nitrite, and phosphorus removal, while denitrification processes remained stable.
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