The effects of microplastics on aerobic granular sludge technology are an emerging issue, although the impact of degradable microplastics (DMPs) on the aerobic granular system is still unexplored. In this study, degradable microplastic polylactic acid (DMP-PLA) was added at three concentrations (5, 15, 40 mg/L), which strengthened the granular stability and consequently stabilized pollutant removal compared to the control (without DMP-PLA). The experiment showed that adding DMP-PLA made cells secrete more extracellular polymeric substances [64.8 mg/g MLVSS (mixed liquor suspended solids)], particularly retaining β-D-glucopyranose polysaccharides in experimental group. In addition, abundant hydrogen bonds were also maintained. The reactor under the stress of DMP-PLA exhibited high pollutant removal efficiency (COD>88%, TP>91%, TIN>86%), indicating high performance of the microbes. Microbial analysis at the genus level indicated that Defuviicoccus and Candidatus_Competibacter were dominant after DMP-PLA addition, which identified denitrifying glycogen-accumulating organisms as beneficial for nitrogenous compound removal. Redundancy analysis showed that the abundance of Candidatus_Competibacter was positively related to the addition of DMP-PLA. This study demonstrated that DMP-PLA was feasibly employed in the aerobic granular water treatment process, and presents a new method to optimize the stability and extracellular secretion of the microbial community.
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http://dx.doi.org/10.1016/j.envpol.2022.119329 | DOI Listing |
Environ Res
January 2025
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China. Electronic address:
Dinotefuran (DIN) is toxic to non-target organisms and accelerates the evolution of antibiotic resistance, which poses a problem for the stable operation of the activated sludge process in wastewater treatment plants (WWTPs). However, the emergence and the transfer mechanism of antibiotic resistance genes (ARGs) in activated sludge systems under DIN stress remains unclear. Thus, in the study, the potential impact of DIN on ARGs and virulence factor genes (VFGs) in aerobic granular sludge (AGS) was investigated in depth using metagenomic binning and functional modules.
View Article and Find Full Text PDFJ Environ Manage
January 2025
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
January 2025
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.
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