The performance of enriched sludge augmented with the B21 strain of Alcaligenes defragrans was compared with that of enriched sludge, as well as with pure Alcaligenes defragrans B21, in the context of a sulfur-oxidizing denitrification (SOD) process. In synthetic wastewater treatment containing 100-1,000 mg NO3-N/L, the single strain-seeded system exhibited superior performance, featuring higher efficiency and a shorter startup period, provided nitrate loading rate was less than 0.2 kg NO3-N/m(3) per day. At nitrate loading rate of more than 0.5 kg NO3-N/m(3) per day, the bioaugmented sludge system showed higher resistance to shock loading than two other systems. However, no advantage of the bioaugmented system over the enriched sludge system without B21 strain was observed in overall efficiency of denitrification. Both the bioaugmented sludge and enriched sludge systems obtained stable denitrification performance of more than 80% at nitrate loading rate of up to 2 kg NO3-N/m(3) per day.
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http://dx.doi.org/10.1007/s00449-007-0115-2 | DOI Listing |
J Environ Manage
January 2025
Department of Environmental Engineering, College of Ecology and Environment, Nanjing Forestry University, Nanjing, 210037, China. Electronic address:
The addition of exogenous quorum sensing signaling molecules to the activated sludge system enables rapid sludge granulation. However, signaling molecules exposed to the environment are easily degraded, and their quorum sensing effects cannot be maintained in the long term. Therefore, they must be frequently added, which leads to an increase in operational costs.
View Article and Find Full Text PDFWater Res
January 2025
Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, 310058, China. Electronic address:
The usage of quaternary ammonium compounds (QACs) as disinfectants has surged dramatically during the COVID-19 pandemic and thereafter. QACs can promote antimicrobial resistance, but the combined effects of QACs and antibiotics in driving resistance evolution were yet revealed. This study aimed to evaluate antibiotic resistance of wastewater microorganisms under coexposure to typical antibiotics and the most widely used QAC, dodecyl dimethyl benzyl ammonium chloride (DDBAC).
View Article and Find Full Text PDFJ Environ Manage
January 2025
Engineering Department, University of Palermo, Viale delle Scienze, Ed. 8, 90128, Palermo, Italy.
The products of an advanced sewage sludge fermentation process can be used to generate polyhydroxyalkanoates (PHAs), precursors of bioplastics considered excellent candidates for replacing petroleum-derived plastics. The aerobic feast-anoxic famine cycling strategy has proven to be an efficient method for enriching sewage sludge microbiota with PHA-producing microorganisms. This work evaluated the effect of different carbon to nitrogen ratios (C/N) of 3.
View Article and Find Full Text PDFJ Environ Manage
January 2025
School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, China. Electronic address:
Anaerobic ammonium oxidation (Anammox) has garnered significant attention due to its ability to eliminate the need for aeration and supplementary carbon sources in biological nitrogen removal process, relying on the capacity of anaerobic ammonium oxidizing bacteria (AnAOB) to directly convert ammonium and nitrite nitrogen into nitrogen gas. This review consolidates the latest advancements in AnAOB research, outlining the mechanisms and enzymatic processes of Anammox, and summarizing the molecular biological techniques used for studying AnAOB, such as 16s rRNA sequencing, qPCR, and metagenomic sequencing. Additionally, it also overviews the currently identified AnAOB species and their distinct metabolic traits, while consolidating strategies to improve their performance.
View Article and Find Full Text PDFJ Environ Manage
January 2025
College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, China. Electronic address:
The treatment of landfill leachate using anaerobic membrane bioreactors (AnMBRs) often faces challenges such as poor removal efficiency, low methane yield and membrane fouling. This study applied AnMBRs with incrementally adding conductive materials to enhance the treatment of landfill leachate under high organic loading rates(35 kg COD/(m∙d)). With 50 g/L activated carbon, COD removal percentages and methane yield increased to 81.
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