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The activated sludge process is the most widely used technology for treating municipal wastewater. However, thick foam often occurs in activated sludge process. Here, we reported for the first time the effect of food waste hydrolysate (FWH) as an external carbon source on defoaming in activated sludge process. The study found that FWH was effective in defoaming at a wide dose range of 50-1600 mg/L total solids, as exhibiting that the foaming tendency of FWH-added foam mixed liquor was reduced to 0 mL-foam/mL-air·min from initial 0.171 mL-foam/mL-air·min in the control without adding FWH with 100 % of defoaming efficiency. Fatty acids, oils, and solid particles in FWH jointly contributed to the deformation. Among these factors, the concentration of long-chain unsaturated fatty acids was mainly responsible for the defoaming. This work provides a cost-effective strategy to solve the foaming problem in activated sludge process as well as providing external carbon sources.
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http://dx.doi.org/10.1016/j.biortech.2024.130900 | DOI Listing |
Microbes Environ
September 2025
Sustainable Process Engineering Center, Department of Chemical Engineering, Faculty of Engineering, Universiti Malaya.
Nitrifying communities in activated sludge play a crucial role in biological nitrogen removal processes in municipal wastewater treatment plants. While extensive research has been conducted in temperate regions, limited information is available on nitrifiers in tropical regions. The present study investigated all currently known nitrifying communities in two full-scale municipal wastewater treatment plants in Malaysia operated under low-dissolved oxygen (DO) (0.
View Article and Find Full Text PDFWater Res
September 2025
Key Laboratory of Groundwater Remediation of Hebei Province and China Geological Survey, Shijiazhuang, 050061, China; The Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geosciences, Shijiazhuang, 050061, China.
Groundwater nitrate (NO) and sulfate (SO) pollution in semi-arid regions has attracted widespread attention. However, unveiling the dynamics and sources of NO and SO in regional groundwater is challenging because of complex anthropogenic activities and hydrogeological conditions. This study combined physicochemistry and multiple stable isotopes (δH-HO, δO-HO, δN-NO, δO-NO, δS-SO, and δO-SO) to explore the spatiotemporal patterns, driving factors, sources, and potential health hazards of NO and SO in groundwater on the Loess Plateau, China.
View Article and Find Full Text PDFJ Environ Manage
September 2025
National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, Ch
The anaerobic ammonia oxidation (anammox) process has attracted considerable interest for its advantages in low energy requirements, reduced sludge output, and eliminating the need for external carbon sources. However, its application is constrained by the long generation time, slow growth, and challenges in enriching anammox bacteria. Studies indicate that carbon material addition significantly accelerates anammox bacteria proliferation, enhances nitrogen removal efficiency, and improves anammox microbial activity.
View Article and Find Full Text PDFJ Environ Manage
September 2025
State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China. Electronic address:
Multivalent cations are commonly employed to accelerate sludge aggregation and granulation, yet they often compromise intragranular mass transfer and diminish microbial activity. Here, the effect of Fe(III) dosing on granule formation and anammox-driven nitrogen removal over a 110-day continuous operation was investigated. Fe(III) supplementation enhanced interactions with extracellular polymeric substances (EPS), transforming flocculent biomass into highly porous granules and yielding a 67.
View Article and Find Full Text PDFJ Contam Hydrol
September 2025
School of Life Sciences, Qufu Normal University, Qufu 273165, PR China.
Biological denitrification is an essential method for sewage treatment, though its efficiency is often constrained by low temperatures and insufficient organic carbon sources. In this study, a novel cold-tolerant heterotrophic nitrification-aerobic denitrification bacterium, Pseudomonas fluorescens sp. Z03, was isolated from activated sludge, and its denitrification performance was evaluated.
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