scholarly journals Effects of carbon to nitrogen ratio on the performance and stability of aerobic granular sludge

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
HyunGu Kim ◽  
JiTae Kim ◽  
DaeHee Ahn
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Extracellular Polymeric Substances ◽  
Influencing Factor ◽  
Granular Sludge ◽  
Optical Microscope ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Carbon To Nitrogen Ratio ◽  
Nitrogen Ratio

The purpose of this study was to assess the nutrient salts removal efficiency and stability of the aerobic granular sludge (AGS) by change in C/N (carbon to nitrogen) ratio. The laboratory-scale experiments were performed to analyze the removal efficiencies for organic matter and contents of nitrogen, MLSS, sludge volume index, and extracellular polymeric substances (EPS) under C/N ratio conditions of 5.0, 10.0, 15.0, and 20.0. The microorganisms were observed using optical microscope and the microbial communities were analyzed using pyrosequencing. The increase in C/N ratio from 5.0 to 20.0 increased the organic matter and nitrogen removal efficiency to 95.9 and 79.1%, respectively. For the EPS contents, an influencing factor of granule stability, the polysaccharides to protein (PS/PN) ratio increased from 0.55 to 0.79. For the microbial community, the <i>Thauera</i> was the most common genus in ending phase occupying 63.7%. This microorganism is regarded as one contributing to organic matter degradation and improved production of EPS including AGS of microorganism, thus, may be an explanation of the results of this study such as increase in organic material in AGS and improvement of denitrification efficiency and contents of EPS with increase in C/N ratio.

scholarly journals The effects of high salinity on nitrogen removal and the formation characteristics of aerobic granular sludge

2019 ◽  
Vol 25 (5) ◽  
pp. 659-667 ◽  
Author(s):  
HyunGu Kim ◽  
DaeHee Ahn
Keyword(s):  
Microbial Community ◽  
Removal Efficiency ◽  
Biological Treatment ◽  
High Salinity ◽  
Granular Sludge ◽  
Suspended Solid ◽  
Microbial Community Analysis ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Mixed Liquor

This study investigated the biological treatment of high-salinity wastewater using aerobic granular sludge (AGS). The removal performance, AGS characteristics, and microbial community were examined under salinity conditions ranging from 0.5 to 3.0 wt.%. When the salinity was increased, the removal efficiency of the chemical oxygen demand did not change substantially. The mean removal efficiency of NH<sub>4</sub><sup>+</sup>-N ranged from 43.7 to 72.6% during the operation period. As for the concentration of extracellular polymeric substances (EPS), the polysaccharide/protein (PS/PN) ratio increased from 0.37 to 0.57. The concentrations of the mixed liquor suspended solid (MLSS) and mixed liquor volatile suspended solid (MLVSS) were 4,560 and 3,170 mg/L, respectively, in the end phase, and the MLVSS/MLSS ratio decreased from 0.81 to 0.69. The sludge volume index (SVI<sub>30</sub>) decreased linearly from 88 to 58 mL/g. In the microbial community analysis, <i>Nitrosomonas</i> species accounted for 22.9% of the total bacteria in the initial phase, whereas <i>Halomonas</i> accounted for 43.2% in the end phase. Hence, the gradually increased salinity appears to facilitate the dominance of halophilic microorganisms in the long-term operation of an AGS-based biological treatment system and the stable retention of AGS.

scholarly journals The Impact of Different Powdered Mineral Materials on Selected Properties of Aerobic Granular Sludge

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 386 ◽  
Author(s):  
Joanna Czarnota ◽  
Adam Masłoń ◽  
Monika Zdeb ◽  
Grzegorz Łagód
Keyword(s):  
Extracellular Polymeric Substances ◽  
Granular Sludge ◽  
Biological Properties ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Mean Values ◽  
The Impact ◽  
Mg Content

This study aimed to evaluate and compare the physical, chemical and biological properties of aerobic granular sludge from reactors with the addition of different powdered mineral materials. These properties have a significant impact on the efficiency of systems in which the biomass in granular form is used. Four identical granular sequencing batch reactors (GSBRs) were adopted for the research performed on a laboratory scale (R1—control reactor; R2, R3 and R4—with materials, PK, PG and PL respectively). The results indicate that the addition of powdered mineral materials improved the properties of biomass in reactors. The SVI5/SVI30 ratio values were significantly lower in the reactors with added materials (approx. 1.3 ± 0.3). The mean values of the sludge volume index at 30 min were the lowest in the R2 (39.8 ± 8.6 mL/g) and R4 (32.8 ± 10.7 mL/g) reactors. The settling velocity of biomass was the highest in the R2 reactor (15.4 ± 6.1 m/h). In the early days of the study, the highest extracellular polymeric substances (EPS) content was found in the biomass from the reactors to which the materials with higher Ca and Mg content were added (380.18–598.30 mg/g MLVSS). The rate of specific oxygen uptake (SOUR) by biomass indicated an insufficient biomass content in the R1 reactor—to 7.85 mg O2/(g MLVSS∙h)—while in the reactors with materials, the SOUR values were at the higher levels.

Research of Carbon and Nitrogen Ratio and Sludge Stability in Aerobic Granular Sludge Bioreactor

2012 ◽  
Vol 518-523 ◽  
pp. 473-477
Author(s):  
Xia Zhao ◽  
Hui Xia Feng ◽  
Feng Jiang ◽  
Na Li Chen ◽  
Xiao Chun Wang
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Aerobic Granular Sludge ◽  
Nitrogen Ratio ◽  
The Stability

In sequencing batch reactor aerobic granular sludge was cultivated, and the influence of influent C/N ratio to aerobic granular sludge was studied. The results showed that the granulation and the settling ability of the sludge were poor in high C/N, however, low C/N was beneficial to the accumulation of microorganism in reactor and MLSS could reach to as high as 8740 mg/L. Lower C/N ratio would lead to increase of particle size and disintegrate of loose structure and overgrowth on filamentous microbe, these were disadvantage of the stability of the system. It was not obvious that influent C/N ratio affected on the organic removal. The COD removal maintained at 87% after the preliminary form particles were formed in reactor. When C/N ratio was 100:15~100:35, the phosphorus removal efficiency was good. If C/N ratio was too high or too low, the formation of sludge granulation would be affected in the process. The influence of C/N ratio to ammonia nitrogen removal efficiency was obvious. While C/N ratio was 100:10, granular sludge had good simultaneous nitrification and denitrification performance, and the average removal of ammonia nitrogen attained to 91%. But low C/N ratio was able to inhibit the activity of nitrifying bacteria and denitrifying bacteria. At that time, ammonia nitrogen removal rate declined sharply in the system.

scholarly journals Composition and Distribution of Extracellular Polymeric Substances in Aerobic Flocs and Granular Sludge

2005 ◽  
Vol 71 (2) ◽  
pp. 1051-1057 ◽  
Author(s):  
B. S. McSwain ◽  
R. L. Irvine ◽  
M. Hausner ◽  
P. A. Wilderer
Keyword(s):  
Extracellular Polymeric Substances ◽  
Cation Exchange Resin ◽  
Chemical Characterization ◽  
Granular Sludge ◽  
Cell Lysis ◽  
Heat Extraction ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Chemical Extraction ◽  
Granule Formation

ABSTRACT Extracellular polymeric substances (EPS) were quantified in flocculent and aerobic granular sludge developed in two sequencing batch reactors with the same shear force but different settling times. Several EPS extraction methods were compared to investigate how different methods affect EPS chemical characterization, and fluorescent stains were used to visualize EPS in intact samples and 20-μm cryosections. Reactor 1 (operated with a 10-min settle) enriched predominantly flocculent sludge with a sludge volume index (SVI) of 120 ± 12 ml g−1, and reactor 2 (2-min settle time) formed compact aerobic granules with an SVI of 50 ± 2 ml g−1. EPS extraction by using a cation-exchange resin showed that proteins were more dominant than polysaccharides in all samples, and the protein content was 50% more in granular EPS than flocculent EPS. NaOH and heat extraction produced a higher protein and polysaccharide content from cell lysis. In situ EPS staining of granules showed that cells and polysaccharides were localized to the outer edge of granules, whereas the center was comprised mostly of proteins. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on a noncellular, protein core. The comparison of EPS methods explains how significant cell lysis and contamination by dead biomass leads to different and opposing conclusions.

scholarly journals Formation and characteristics of filamentous granular sludge

2020 ◽  
Author(s):  
Wenjing Cheng ◽  
Liguo Zhang ◽  
Wenjie Xu ◽  
Yichen Sun ◽  
Junfeng Wan ◽  
...  
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Microbial Diversity ◽  
Removal Efficiency ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Nutrients Removal ◽  
Toc Removal ◽  
Removal Efficiencies ◽  
Research Hotspots

Abstract Aerobic granular sludge process as a promising biotechnology has been one of the research hotspots in the area of wastewater treatment during the last two decades. In our study, after around 60 days' operation, filamentous granular sludge (FGS) was formed under low aeration (SAV = 0.085 cm/s) and multi-feeding conditions. The characteristics of FGS and the performance of the FGS system for organic matter and nutrients removal were investigated. The results showed that COD and TOC removal efficiencies were relatively stable, while COD removal efficiency increased from 82% to 94% in the presence of sulfamethoxazole (SMZ) at low concentration (1 mg/L). At the same time, the TP removal efficiency could be improved and maintained at around 75%, while TN removal efficiency was flocculated at around 50%. The analysis of microbial diversity showed that Thiothrix and Trichococcus as typical filamentous species were detected and dominant in the FGS system. The abundance of Thiothrix increased from 15% to 34%, while Trichococcus decreased from 23% to 3% in the presence of SMZ.

Performance of aerobic granular sludge at variable circulation rate in anaerobic–aerobic conditions

2014 ◽  
Vol 69 (11) ◽  
pp. 2252-2257 ◽  
Author(s):  
Hasnida Harun ◽  
Aznah Nor Anuar ◽  
Zaini Ujang ◽  
Noor Hasyimah Rosman ◽  
Inawati Othman
Keyword(s):  
Municipal Wastewater ◽  
Granular Sludge ◽  
Ammonia Removal ◽  
Soy Sauce ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Circulation Rate ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Mixed Liquor

Aerobic granular sludge (AGS) has been applied to treat a broad range of industrial and municipal wastewater. AGS can be developed in a sequencing batch reactor (SBR) with alternating anaerobic–aerobic conditions. To provide anaerobic conditions, the mixed liquor is allowed to circulate in the reactor without air supply. The circulation flow rate of mixed liquor in anaerobic condition is the most important parameter of operation in the anaerobic-AGS processes. Therefore, this study investigates the effect of circulation rate on the performance of the SBR with AGS. Two identical reactors namely R1 and R2 were operated using fermented soy sauce wastewater at circulation rate of 14.4 and 36.0 l/h, respectively. During the anaerobic conditions, the wastewater was pumped out from the upper part of the reactor and circulated back into the bottom of the reactor for 230 min. A compact and dense AGS was observed in both reactors with a similar diameter of 2.0 mm in average, although different circulation rates were adopted. The best reactor performance was achieved in R2 with chemical oxygen demand removal rate of 89%, 90% total phosphorus removal, 79% ammonia removal, 10.1 g/l of mixed liquor suspended solids and a sludge volume index of 25 ml/g.

Start-up of an aerobic granular sequencing batch reactor for the treatment of winery wastewater

2009 ◽  
Vol 60 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
S. López–Palau ◽  
J. Dosta ◽  
J. Mata-Álvarez
Keyword(s):  
Organic Matter ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Particle Diameter ◽  
Granular Sludge ◽  
Average Density ◽  
Aerobic Granular Sludge ◽  
Organic Load ◽  
Winery Wastewater ◽  
Start Up

Aerobic granular sludge was cultivated in a sequencing batch reactor (SBR) in order to remove the organic matter present in winery wastewater. The formation of granules was performed using a synthetic substrate. The selection parameter was the settling time, as well as the alternation of feast-famine periods, the air velocity and the height/diameter ratio of the reactor. After 10 days of operation under these conditions, the first aggregates could be observed. Filamentous bacteria were still present in the reactor but they disappeared progressively. During the start-up, COD loading was increased from 2.7 to 22.5 kg COD/(m3 day) in order to obtain a feast period between 30 and 60 minutes. At this point, granules were quite round, with a particle diameter between 3.0 and 4.0 mm and an average density of 6 g L−1. After 120 days of operation, synthetic media was replaced by real winery wastewater, with a COD loading of 6 kg COD/(m3 day). The decrease of the organic load implied a reduction of the aggregate diameter and a density increase up to 13.2 g L−1. The effluent was free of organic matter and the solids concentration in the reactor reached 6 g VSS L−1.

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