In this study, the filamentous bulking (FB) with moderate and excessive levels were demonstrated to induce anammox failure by inhibiting nitrogen (N) removal and biomass retention. The low external mass transfer resulted from high liquid-surface friction and low turbulence of filamentous surface was considered the "trigger" of anammox failure, which decreased flux of nitrogen flow toward granular surface and directly limited N-removal loading, which meanwhile exposed granules with N-scarcity environment and indirectly inhibited N-removal bio-activity. Low bio-activity performed poor extracellular polymeric substances secretion further destroyed bio-aggregation with low suface hydrophobicity, which acted as "accelerator" for granule disintegration and biomass washout, ultimatly leading to anammox failure. Fortunately, incresing hydraulic shear stress could eradicate FB's negative effects without inhibiting FB itself, which promoted re-granulation and N-remval restore by enhancing external mass transfer more than hydraulic detachment. Enhancing mechanical stirring with FB level was necessary to maintain stable operation of granular anammox system.
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http://dx.doi.org/10.1016/j.biortech.2024.130336 | DOI Listing |
Bioresour Technol
January 2025
Suez, CIRSEE, 38 rue du Président Wilson, 78230 Le Pecq, France. Electronic address:
Volatile fatty acid accumulation is a common issue encountered in anaerobic digestion, indicating potential process failure through the inhibition of microorganisms consuming those acids. However, the related inhibition mechanisms and thresholds remain poorly characterized for digesters treating concentrated feedstocks such as food waste. Considering two inocula adapted to high ammonia concentration, this study assessed the inhibition of acetate or propionate consumers exposed to various salts (NHHCO, NaHCO or KHCO) under mesophilic conditions in a range of total cation concentration between 0.
View Article and Find Full Text PDFBioresour Technol
March 2024
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
In this study, the filamentous bulking (FB) with moderate and excessive levels were demonstrated to induce anammox failure by inhibiting nitrogen (N) removal and biomass retention. The low external mass transfer resulted from high liquid-surface friction and low turbulence of filamentous surface was considered the "trigger" of anammox failure, which decreased flux of nitrogen flow toward granular surface and directly limited N-removal loading, which meanwhile exposed granules with N-scarcity environment and indirectly inhibited N-removal bio-activity. Low bio-activity performed poor extracellular polymeric substances secretion further destroyed bio-aggregation with low suface hydrophobicity, which acted as "accelerator" for granule disintegration and biomass washout, ultimatly leading to anammox failure.
View Article and Find Full Text PDFSci Total Environ
February 2024
Faculty of Civil and Environmental Engineering, Technion, Haifa 32000, Israel. Electronic address:
The partial nitritation and anammox (PN/A) process has gained popularity for the treatment of nitrogen removal in wastewater due to significant energy savings and its potentially much lower CO footprint. However, the treatment of mainstream municipal wastewater by PN/A has been limited mainly due to its unsuitable composition. In this research, we apply ion exchange using a zeolite column to selectively remove and concentrate ammonium from mainstream municipal wastewater.
View Article and Find Full Text PDFEnviron Int
June 2022
Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China. Electronic address:
Heterotrophic bacteria grow on influent organics or soluble microbial products (SMP) in wastewater anammox processes, playing key roles in facilitating microbial aggregation and reducing excess nitrate. The overgrowth of heterotrophs represents one of the major causes of anammox process failure, while the metabolic functions of coexisting heterotrophs and their roles in anammox process remain vague. This study aimed at revealing metabolic interactions between AnAOB and active SMP assimilators by integrating C DNA-stable isotope probing, metabolomic and metagenomic approaches.
View Article and Find Full Text PDFBioresour Technol
April 2022
Department of Environmental & IT Convergence Engineering, Chungnam National University, Daejeon, Republic of Korea. Electronic address:
The cultivation of anaerobic ammonia oxidizing bacteria (anammox) has gained enormous awareness over the last few decades. Although numerous studies focus massively on successfully growing these anammox to different enrichment environments, in reality, the failure rates are somewhat comparable to the reported success rates. This study combines a variety of measurement techniques to observe and monitor the sequence of a bioreactor performance decline following elevated influent substrate concentration.
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