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Bioresource Technology Mar 2024In response to the challenges of limited nutrient removal and the difficulty in forming aerobic granular sludge (AGS) with low carbon to nitrogen (C/N) ratios, a novel...
Two-stage sequencing batch reactors with added iron shavings for nutrient removal and aerobic sludge granulation treating real wastewater with low carbon to nitrogen ratios.
In response to the challenges of limited nutrient removal and the difficulty in forming aerobic granular sludge (AGS) with low carbon to nitrogen (C/N) ratios, a novel two-stage sequencing batch reactors (SBRs) (R1 and R2) system with added iron shavings was proposed and established. The results showed that AGS was developed and nitrogen (82.8 %) and phosphorus (94.7 %) were effectively removed under a C/N ratio at 1.7 ± 0.5. The average size of R1 and R2 increased from 45.3 μm to 138.7 μm and 132.8 μm. Under high biological selective pressure, phosphorus accumulating organisms like Comamonadaceae (14.8 %) and Chitinophagales (5.7 %) experienced enrichment in R1. Furthermore, R2 exhibited an increased abundance of nitrifying bacteria (2.3 %) and a higher proportion of nitrogen removal through autotrophic denitrification (>17.5 %). Overall, this study introduces an innovative two-stage SBRs with added iron shavings, offering a novel approach for the treatment of low C/N ratios wastewater.
Topics: Wastewater; Sewage; Waste Disposal, Fluid; Nitrogen; Carbon; Aerobiosis; Bioreactors; Phosphorus
PubMed: 38281551
DOI: 10.1016/j.biortech.2024.130380 -
Water Research Mar 2024Ammonia retention and recovery from high-nitrogenous wastewater are new concepts being used for nitrogen management. A microaerophilic activated sludge system was...
Enhanced granulation of activated sludge in an airlift reactor for organic carbon removal and ammonia retention from industrial fermentation wastewater: A comparative study.
Ammonia retention and recovery from high-nitrogenous wastewater are new concepts being used for nitrogen management. A microaerophilic activated sludge system was developed to convert organic nitrogen into ammonia and retain it for its recovery; however, the settleability of activated sludge remains a challenge. Therefore, this study proposed an aerobic granular sludge system as a potential solution. Two types of sequencing batch reactors-airlift and upflow reactors-were operated to investigate the feasibility of fast granule formation, the performance of organic carbon removal and ammonia retention, and the dynamics of microbial community composition. The operation fed with industrial fermentation wastewater demonstrated that the airlift reactor ensured a more rapid granule formation than the upflow reactor because of the high shear force, and it maintained a superior ammonia retention stability of approximately 85 %. Throughout the operational period, changes in hydraulic retention time (HRT), settling time, and exchange ratio altered the granular particle sizes and microbial community compositions. Rhodocyclaceae were replaced with Comamonadaceae, Methylophilaceae, Xanthomonadaceae, and Chitinophagaceae as core taxa instrumental in granulation, likely because of their extracellular polymeric substance secretion. As the granulation process progressed, a significant decrease in the relative abundances of nitrifying bacteria-Nitrospiraceae and Nitrosomonadaceae-was observed. The reduction of settling time and HRT enhanced granulation and inhibited the activity of nitrifying bacteria. The success in granulation for ammonia conversion and retention in this study accelerates the paradigm shift from ammonia removal to ammonia recovery from industrial fermentation wastewater.
Topics: Wastewater; Sewage; Ammonia; Fermentation; Carbon; Extracellular Polymeric Substance Matrix; Waste Disposal, Fluid; Bioreactors; Bacteria; Aerobiosis; Nitrogen
PubMed: 38244299
DOI: 10.1016/j.watres.2023.121091 -
PloS One 2024The activated sludge was collected from the Membrane BioReactor (MBR) pool of the sewage treatment system of Sanxing Town, Jintang County, Chengdu, to obtain a good...
The activated sludge was collected from the Membrane BioReactor (MBR) pool of the sewage treatment system of Sanxing Town, Jintang County, Chengdu, to obtain a good population of heterotrophic nitrifying/aerobic denitrifying (HNAD) bacteria. After undergoing enrichment, isolation, and purification, the HNAD bacteria were selected using the pure culture method. The 16S rDNA molecular technology was used to determine the taxonomy of bacteria. The heterophic nitrifying ability and denitrification capacity of HNAD strains was ascertained through their growth characteristics in heterotrophic nitrification and denitrification media. The results showed that 53 HNAD strains selected from the MBR pool belonged to 2 phyla, 3 classes, 6 orders, 6 families, and 7 genera, with 26 species. Acinetobacter was the largest and dominant genus. Among these, strains numbered (bacterial strain) SW21HD14, SW21HD17, and SW21HD18 were potentially new species in the Acinetobacter genus. Each HNAD strain showed a significant heterotrophic nitrifying and aerobic denitrifying efficiency compared with the control strain (P < 0.05). Specifically, 10 strains demonstrated ammonia nitrogen degradation of greater than 70 mg·L-1 and 9 strains demonstrated nitrate nitrogen degradation above 150 mg·L-1. The HNAD bacteria, which were selected from the MBR pool of sewage treatment system of the Sanxing Town sewage treatment plant, exhibited rich diversity and strong nitrogen removal ability. These findings offered an effective strain source and theoretical basis for implementing biological denitrification technology that involves synchronous nitrification and denitrification.
Topics: Humans; Sewage; Denitrification; Aerobiosis; Nitrification; Bacteria, Aerobic; Bacteria; Heterotrophic Processes; Nitrogen; Nitrites
PubMed: 38236927
DOI: 10.1371/journal.pone.0293136 -
Bioresource Technology Mar 2024This study provides for the first time a systematic understanding of Acinetobacter indicus CZH-5 performance, metabolic pathway and genomic characteristics for aerobic...
This study provides for the first time a systematic understanding of Acinetobacter indicus CZH-5 performance, metabolic pathway and genomic characteristics for aerobic nitrogen (N) and phosphorus (P) removal. Acinetobacter indicus CZH-5 showed promising performance in heterotrophic nitrification aerobic denitrification and aerobic phosphorus removal. Under optimal conditions, the maximum ammonia-N, total nitrogen and orthophosphate-P removal efficiencies were 90.17%, 86.33%, and 99.89%, respectively. The wide tolerance range suggests the strong environmental adaptability of the bacteria. The complete genome of this strain was reconstructed. Whole genome annotation was used to re-construct the N and P metabolic pathways, and related intracellular substance metabolic pathways were proposed. The transcription levels of related functional genes and enzyme activities further confirmed these metabolic mechanisms. N removal was achieved via the nitrification-denitrification pathway. Furthermore, CZH-5 exhibited significant aerobic P uptake, with phosphate diesters as the main species of intracellular P.
Topics: Nitrification; Denitrification; Phosphorus; Nitrites; Aerobiosis; Heterotrophic Processes; Phosphates; Nitrogen; Genomics; Acinetobacter
PubMed: 38228222
DOI: 10.1016/j.biortech.2024.130322 -
Chemosphere Feb 2024The goal of this study was to investigate abiotic pharmaceutical removal and abiotic pharmaceutical effects on aerobic granular sludge morphology. For 80 days, a...
The goal of this study was to investigate abiotic pharmaceutical removal and abiotic pharmaceutical effects on aerobic granular sludge morphology. For 80 days, a pharmaceutical mixture containing approximately 150 μg/L each of diclofenac, erythromycin, and gemfibrozil was fed to an aerobic granular sludge sequencing batch reactor and granule characteristics were compared with those from a control reactor. Aqueous and solid phase pharmaceutical concentrations were monitored and staining was used to assess changes in biofilm structures. Solid phase pharmaceutical concentrations were elevated over the first 12 days of dosing; however, they then dropped, indicative of desorption. The lipid content in pharmaceutical-exposed granules declined by approximately half over the dosing period, though the relative concentrations of other key biofilm components (proteins, alpha-, and beta-polysaccharides) did not change. Batch experiments were conducted to try to find an explanation for the desorption observed, but reduced solid phase pharmaceutical concentrations could not be linked with the presence of common wastewater constituents such as ammonia or phosphate. Sorption of all three compounds was modeled best by the Henry isotherm, indicating that, even at 150 μg/L, granules' sorption site coverage was incomplete. Altogether, this study demonstrates that simplified batch systems may not accurately represent the complex abiotic processes occurring in flow-through, biotic systems.
Topics: Sewage; Bioreactors; Aerobiosis; Wastewater; Pharmaceutical Preparations; Waste Disposal, Fluid; Nitrogen
PubMed: 38211794
DOI: 10.1016/j.chemosphere.2024.141187 -
Journal of Environmental Management Feb 2024An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an...
An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an ammonia nitrogen (NH-N) removal efficiency of 98.53%. It can also remove heavy metals by microbial induced calcium precipitation (MICP) with a Ca removal efficiency of 75.91%. Optimal conditions for HN-AD and mineralization of the strain were determined by kinetic analysis (pH = 7, C/N = 2.0, Ca = 70.0 mg L, NH-N = 5.0 mg L). Growth curves and nitrogen balance elucidated nitrogen degradation pathways capable of converting NH-N to gaseous nitrogen. The analysis of the bioprecipitation showed that Zn and Cd were removed by the MICP process through co-precipitation and adsorption (maximum removal efficiencies of 93.39% and 80.70%, respectively), mainly ZnCO, CdCO, ZnHPO, Zn(PO) and Cd(PO). Strain HM12 produces humic and fulvic acids to counteract the toxicity of pollutants, as well as aromatic proteins to increase extracellular polymers (EPS) and promote the biomineralization process. This study provides a experimental evidence for the simultaneous removal of multiple pollutants from nutrient-poor waters.
Topics: Ammonia; Denitrification; Acinetobacter calcoaceticus; Calcium; Nitrites; Kinetics; Cadmium; Aerobiosis; Nitrification; Metals, Heavy; Nitrogen; Heterotrophic Processes; Nutrients; Environmental Pollutants
PubMed: 38176381
DOI: 10.1016/j.jenvman.2023.119912 -
Bioresource Technology Feb 2024This work aimed to elucidate the metabolic mechanism of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria influenced by varying concentrations of...
This work aimed to elucidate the metabolic mechanism of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria influenced by varying concentrations of ammonium nitrogen (NH-N) in high-strength synthetic wastewater treatment. The results showed that the removal rates of NH-N and total nitrogen, along with enzymatic activities related to nitrification and denitrification, increased with rising NH-N concentrations (N:500 mg/L, N:1000 mg/L and N:2000 mg/L). The relative abundances of HN-AD bacteria were 50 %, 62 % and 82 % in the three groups. In the N group, the cAMP signaling pathway, glycerophospholipid metabolites, purines and pyrimidines related to DNA/RNA synthesis, electron donor NAD-related energy, the tricarboxylic acid (TCA) cycle and glutamate metabolism were upregulated. Therefore, influent NH-N at 2000 mg/L promoted glutamate metabolism to accelerate the TCA cycle, and enhanced cellular energy and advanced denitrification activity of bacteria for HN-AD. This mechanism, in turn, enhanced microbial growth and the carbon and nitrogen metabolism of bacteria for HN-AD.
Topics: Nitrification; Denitrification; Ammonium Compounds; Aerobiosis; Heterotrophic Processes; Bacteria; Nitrogen; Glutamates; Nitrites
PubMed: 38168563
DOI: 10.1016/j.biortech.2023.130278 -
The Science of the Total Environment Feb 2024A naturally occurring multispecies bacterial community composed of Bacillus cereus and two novel bacteria (Microbacterium forte sp. nov. and Stenotrophomonas goyi sp....
A naturally occurring multispecies bacterial community composed of Bacillus cereus and two novel bacteria (Microbacterium forte sp. nov. and Stenotrophomonas goyi sp. nov.) has been identified from a contaminated culture of the microalga Chlamydomonas reinhardtii. When incubated in mannitol- and yeast extract-containing medium, this bacterial community can promote and sustain algal hydrogen production up to 313 mL H·L for 17 days and 163.5 mL H·L for 25 days in high-cell (76.7 μg·mL of initial chlorophyll) and low-cell density (10 μg·mL of initial chlorophyll) algal cultures, respectively. In low-cell density algal cultures, hydrogen production was compatible with algal growth (reaching up to 60 μg·mL of chlorophyll). Among the bacterial community, M. forte sp. nov. was the sole responsible for the improvement in hydrogen production. However, algal growth was not observed in the Chlamydomonas-M. forte sp. nov. consortium during hydrogen-producing conditions (hypoxia), suggesting that the presence of B. cereus and S. goyi sp. nov. could be crucial to support the algal growth during hypoxia. Still, under non‑hydrogen producing conditions (aerobiosis) the Chlamydomonas-M. forte sp. nov. consortium allowed algal growth (up to 40 μg·mL of chlorophyll) and long-term algal viability (>45 days). The genome sequence and growth tests of M. forte sp. nov. have revealed that this bacterium is auxotroph for biotin and thiamine and unable to use sulfate as sulfur source; it requires S-reduced forms such as cysteine and methionine. Cocultures of Chlamydomonas reinhardtii and M. forte sp. nov. established a mutualistic association: the alga complemented the nutrient deficiencies of the bacterium, while the bacterium released ammonium (0.19 mM·day) and acetic acid (0.15 mM·day) for the alga. This work offers a promising avenue for photohydrogen production concomitant with algal biomass generation using nutrients not suitable for mixotrophic algal growth.
Topics: Chlamydomonas reinhardtii; Microbacterium; Chlorophyll; Chlamydomonas; Acetic Acid; Bacteria; Hypoxia; Hydrogen
PubMed: 38159768
DOI: 10.1016/j.scitotenv.2023.169559 -
Journal of Hazardous Materials Mar 2024Tire materials (TMs) present a notable hazard due to their potential to release harmful chemicals and microplastics into the environment. They can infiltrate wastewater...
Tire materials (TMs) present a notable hazard due to their potential to release harmful chemicals and microplastics into the environment. They can infiltrate wastewater treatment plants, where their effects remain inadequately understood, raising concerns regarding their influence on treatment procedures. Thus, this study investigated the impact of TMs in wastewater (10, 25, 50 mg/L) on wastewater treatment efficiency, biomass morphology, and microbial composition in aerobic granular sludge (AGS) reactors. TM dosage negatively correlated with nitrification and denitrification efficiencies, reducing overall nitrogen removal, but did not affect the efficiency of chemical-oxygen-demand removal. The presence of TMs increased the diameter of the granules due to TM incorporation into the biomass. The most frequently leached additives from TMs were N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine, benzothiazole (BTH), and 2-hydroxybenzothiazole. In the treated wastewater, only BTH and aniline were detected in higher concentrations, which indicates that tire additives were biodegraded by AGS. The microbial community within the AGS adapted to TMs and their chemicals, highlighting the potential for efficient degradation of tire additives by bacteria belonging to the genera Rubrivivax, Ferruginibacter, and Xanthomonas. Additionally, our research underscores AGS's ability to incorporate TMs into biomass and effectively biodegrade tire additives, offering a promising solution for addressing environmental concerns related to TMs.
Topics: Sewage; Wastewater; Nitrogen Compounds; Waste Disposal, Fluid; Biomass; Plastics; Nitrogen; Bioreactors; Aerobiosis
PubMed: 38113742
DOI: 10.1016/j.jhazmat.2023.133223 -
Journal of Environmental Management Feb 2024The effect of mix-cultured aerobic denitrifying microorganisms on the water remediation has been extensively explored, but little is known about the performance of...
The effect of mix-cultured aerobic denitrifying microorganisms on the water remediation has been extensively explored, but little is known about the performance of mix-cultured low efficiency fungi on denitrification. In this study, two kinds of aerobic denitrifying fungi (Trichoderma afroharzianum H1 and Aspergillus niger C1) were isolated from reservoirs, improved the capacity by mix-cultured. The results showed a difference between northern and southern reservoirs, the dominants of genera were Cystobasidium and Acremonium. The removals of total nitrogen (TN) was 12.00%, 7.53% and 69.33% in Trichoderma afroharzianum H1, Aspergillus niger C1 and mix-cultured (C1 and H1) under the denitrification medium. The contents of ATP and electron transport system activity in mix-cultured amendment were increased by 42.54% and 67.52%, 1.72 and 2.91 times, respectively. Besides, the raw water experiment indicated that TN removals were 24.05%, 12.66% and 73.42% in Trichoderma afroharzianum H1, Aspergillus niger C1 and mix-cultured. The removals of dissolved organic carbon in mix-cultured were increased 35.02% and 50.46% compared to Trichoderma afroharzianum H1 and Aspergillus niger C1. Therefore, mix-cultured of two low efficiency aerobic denitrifying fungi has been considered as a novelty perspective for mitigation of drinking water source.
Topics: Drinking Water; Denitrification; Aerobiosis; Nitrogen; Mycobiome; Hypocreales; Aspergillus
PubMed: 38109827
DOI: 10.1016/j.jenvman.2023.119842