An anoxic/oxic membrane bioreactor (AO) and three pilot-scale anaerobic side stream reactors (ASSR) coupled MBRs (ASSR-MBRs), packed with 0%, 25% and 50% carriers in ASSRs, were continuously operated to study the mechanisms for sludge reduction. Four systems showed efficient COD and NH-N removal, while packing carriers significantly enhanced nitrogen removal. 25% filling fraction (AP) achieved the highest sludge reduction efficiency of 50.5% compared to 0% (21.7%) and 50% (39.7%). Compared to ASSR-MBR, carriers enhanced the release of dissolved organic matters, and accelerated the secretion of enzyme for cell lysis and hydrolysis. In AP, the presence of carriers prompted the formation of environment propitious to sludge reduction in bulk sludge. AP tended to enrich hydrolytic, fermentative and denitrifying bacteria to accelerate hydrolysis process, while excessive carriers had negative effect on biomass stability and movement of carriers.
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http://dx.doi.org/10.1016/j.biortech.2020.123925 | DOI Listing |
Environ Toxicol Chem
January 2025
Aquatic Toxicology Laboratory, St Cloud State University, Minnesota, USA.
Treated municipal wastewater effluent is an important pathway for Contaminants of Emerging Concern (CEC) to enter aquatic ecosystems. As the aging wastewater infrastructure in many industrialized countries requires upgrades or replacement, assessing new treatment technologies in the context of CEC effects may provide additional support for science-based resource management. Here, we used three lines of evidence, analytical chemistry, fish exposure experiments, and fish and water microbiome analysis, to assess the effectiveness of membrane bioreactor treatment (MBR) to replace traditional activated sludge treatment.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450046, China. Electronic address:
Nitrate (NO) pollution in groundwater is a worldwide environmental issue, particularly in developed planting-breeding areas where there is a substantial presence of nitrogen-related sources. Here, we explored the key sources and potential health risks of NO in a typical planting-breeding area in the North China Plain based on dual stable isotopes and Monte Carlo simulations. The analysis results revealed that the NO concentration ranged from 0.
View Article and Find Full Text PDFEnviron Technol
January 2025
Chengdu Center, China Geological Survey (Geosciences Innovation Center of Southwest China), Chengdu, People's Republic of China.
The acid mine drainage (AMD) is characterized by its highly acidic nature and elevated concentrations of metal ions, thereby exerting significant impacts on both human health and the environment. This study employed a dispersed alkaline substrate (DAS) consisting of thermal activation magnesite and pine shavings for the treatment of AMD. The investigation focused on determining the optimal thermal activation conditions of magnesite, evaluating the effectiveness of the DAS in regulating acidity and removing metal ions from AMD, identifying critical factors influencing treatment efficiency, and conducting toxicity assessment on the effluent.
View Article and Find Full Text PDFWater Res X
May 2025
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
Widespread polyethylene terephthalate microplastics (PET MPs) have played unintended role in nitrous oxide (NO) turnovers (i.e., production and consumption) at wastewater treatment plants (WWTPs).
View Article and Find Full Text PDFWater Res X
May 2025
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
Although the treatment of sludge with free nitrous acid can effectively recover short chain fatty acids, the feasibility of sequential nitrite reduction and methane recovery without acidic pH adjustment is still scarcely studied. Therefore, this study aimed to provide insights into the effect of nitrite at different levels on nitrite reduction and methane production. The results showed that the nitrite concentrations of 100, 200, 400 and 800 mg/L were completely reduced in 1, 2, 2 and 4 days, respectively.
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