A pilot-scale activated sludge bioreactor was filled with immobile carrier to treat high ammonium wastewater. Autotrophic nitrogen elimination occurred rapidly by inoculating nitrifying activated sludge and anammox biofilm. As the ammonium loading rate increased, nitrogen removal rate of 1.2kgNm(-3)d(-1) was obtained with the removal efficiency of 80%. Activated sludge diameter distribution profiles presented two peak values, indicating simultaneous existence of flocculent and granular sludge. Red granular sludge was observed in the reactor. Furthermore, the results of morphological and molecular analysis showed that the characteristics of granular sludge were similar to that of biofilm, while much different from the flocculent sludge. It was assumed granular sludge was formed through the continuous growth and detachment of anammox biofilm. The mechanism of granular sludge formation was discussed and the procedure model was proposed. According to the experimental results, the integrated fixed-biofilm activated sludge reactor provided an alternative to nitrogen removal based on anammox.
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http://dx.doi.org/10.1016/j.chemosphere.2015.02.001 | DOI Listing |
Bioresour Technol
January 2025
School of Environmental Engineering, Henan University of Technology, Zhengzhou 450001, China; Zhengzhou Key Laboratory of Water Safety and Water Ecology Technology, Zhengzhou 450001, China; Henan International Joint Laboratory of Environmental Pollution Remediation and Grain Quality Security, Zhengzhou 450001, China.
This study integrates partial denitrification/Anammox (PD/A) with hydroxyapatite (HAP) crystallization in a single reactor, achieving simultaneous nitrogen and phosphorus removal along with phosphorus recovery. By adjusting pH, sludge concentration, low COD/TN ratio, and applying moderate dissolved oxygen stress, the system operated stably and promoted the synergistic growth of HAP and biomass. Results showed a nitrogen removal efficiency (NRE) of 94.
View Article and Find Full Text PDFEnviron Res
January 2025
School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
Iron-loaded diatomite (Fe-DE) was developed as the innovative material to enhance anammox granular sludge (AnGS) and mainstream anammox performance. By adding Fe-DE with the Fe:DE ratio of 1:20 and the dosage of 3 g/L, the start-up period of mainstream anammox process was shortened from 29 d to 17 d and its nitrogen removal rate was increased from 0.234 kg N/(m·d) to 0.
View Article and Find Full Text PDFEnviron 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 PDFWater Res
December 2024
Deptartment of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, HZ 2629, the Netherlands; Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
Extracellular Polymeric Substances (EPS) are ubiquitous in biological wastewater treatment (WWT) technologies like activated sludge systems, biofilm reactors, and granular sludge systems. EPS recovery from sludge potentially offers a high-value material for the industry. It can be utilized as a coating in slow-release fertilizers, as a bio-stimulant, as a binding agent in building materials, for the production of flame retarding materials, and more.
View Article and Find Full Text PDFEnviron Res
January 2025
Key Laboratory of Water Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100123, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
Stable inhibition of nitrite-oxidizing bacteria (NOB) is a significant challenge in achieving partial nitrification (PN) and partial nitrification-anaerobic ammonia oxidation (PNA). Growing evidence suggested that NOB can develop resistance to suppression over time, leading to the re-enrichment of NOB within reactors. To address these issues, this study aimed to achieve stable PN by regulating SRT to selectively washout NOB during the lag phase of activity recovery following FA/FNA exposure.
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