How does shear affect aggregation in granular sludge sequencing batch reactors? Relations between shear, hydrophobicity, and extracellular polymeric substances

2008 ◽  
Vol 58 (2) ◽  
pp. 267-276 ◽  
Author(s):  
E. Dulekgurgen ◽  
N. Artan ◽  
D. Orhon ◽  
P. A. Wilderer
Keyword(s):  
Extracellular Polymeric Substances ◽  
Batch Reactor ◽  
Cell Surface Hydrophobicity ◽  
Granular Sludge ◽  
Surface Hydrophobicity ◽  
Physical Stress ◽  
Batch Reactors ◽  
Mechanical Mixing ◽  
Hydrodynamic Shear ◽  
Increasing Trends

The objective was to provide an answer to “how to grow/survive in aggregative physiology” through evaluating the relation between physical stress and observed biomass characteristics. For that, a lab-scale sequencing batch reactor was operated at an anaerobic-aerobic mode and under altered hydraulic selection pressures of settling time (10–1 min) and hydrodynamic shear rates due to mechanical mixing (15.5–12.0 cm/s) and/or aeration (1.76–0.24 cm/s). Main physical stress experienced by the biomass was mechanical mixing, which resulted in extreme shearing conditions at the first operational stage (days 1–86), during which first granules formed but settling properties deteriorated and biomass was almost totally washed out. After relaxing the overall shear stress at the second stage, biomass formation accelerated, settling properties enhanced and granulation proceeded (days 86–136), until disturbance of the process at the last month of operation (days 136–163). Aggregative physiology-related parameters, being cell surface hydrophobicity and extracellular polymeric substances (EPS), followed increasing trends parallel to the progress of granulation, and then decreased upon disturbance of the process. There was an increase in the EPS production also during the first stage under extreme shear, while a substantial amount of biomass was present in the system. A direct correlation was also found between %hydrophobicity and EPS-composition expressed as ExoPN/ExoPS.

The effect of upflow air velocity on the structure of aerobic granules cultivated in a sequencing batch reactor

2004 ◽  
Vol 49 (11-12) ◽  
pp. 35-40 ◽  
Author(s):  
J.H. Tay ◽  
Q.S. Liu ◽  
Y. Liu
Keyword(s):  
Shear Force ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Batch Reactors ◽  
Aerobic Granules ◽  
Sequencing Batch Reactors ◽  
Air Velocity ◽  
Hydrodynamic Shear ◽  
Biomass Retention

The effect of upflow air velocity on the formation and structure of aerobic granules was studied in three column sequencing batch reactors. Upflow aeration would be the major cause of hydrodynamic shear force in the column reactor. Results showed that high upflow air velocity resulted in more compact, denser, rounder, stronger and smaller aerobic granules, while high biomass retention in the reactor was achieved. It was found that high upflow air velocity could induce granular sludge to secrete more cell polysaccharides which in turn contributed to the compact and strong structure. It appears from this study that the structure of aerobic granules could be controlled by manipulating the upflow air velocity.

Effects of extracellular polymeric substances on granulation of anoxic sludge in sequencing batch reactor

2012 ◽  
Vol 66 (3) ◽  
pp. 543-548
Author(s):  
Binbin Wang ◽  
Shunlian Liu ◽  
Hongmei Zhao ◽  
Xinyan Zhang ◽  
Dangcong Peng
Keyword(s):  
Extracellular Polymeric Substances ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Cation Exchange Resin ◽  
Granular Sludge ◽  
Extracellular Proteins ◽  
Extracellular Polysaccharides ◽  
Positive Role ◽  
Start Up ◽  
Sludge Granulation

Variations of extracellular polymeric substances (EPS) and its components with sludge granulation were examined in a lab-scale sequencing batch reactor (SBR) which was fed with sodium nitrate and sodium acetate. Ultrasonication plus cation exchange resin (CER) were used as the EPS extraction method. Results showed that after approximately 90 d cultivation, the sludge in the reactor was almost granulated. The content of extracellular polysaccharides increased from 10.36 mg/g-VSS (volatile suspended solids) at start-up with flocculent sludge to 23.18 mg/g-VSS at 91 d with matured granular sludge, while the content of extracellular proteins were almost unchanged. Polysaccharides were the major components of EPS in anoxic granular sludge, accounting for about 70.6–79.0%, while proteins and DNA accounted for about 16.5–18.9% and 4.6–9.9%, respectively. It is proposed that EPS play a positive role in anoxic sludge granulation and polysaccharides might be strongly involved in aggregation of flocs into granules.

Performances of a granular sequencing batch reactor (GSBR)

2007 ◽  
Vol 55 (8-9) ◽  
pp. 125-133 ◽  
Author(s):  
M. Torregrossa ◽  
G. Di Bella ◽  
G. Viviani ◽  
A. Gnoffo
Keyword(s):  
Removal Efficiency ◽  
Bubble Column ◽  
Batch Reactor ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Aerobic Granulation ◽  
Reactor Configuration ◽  
N Removal ◽  
Hydrodynamic Shear ◽  
Removal Efficiencies

Aerobic granulation in sequencing batch reactors is widely reported in literature and in particular in SBAR (Sequencing batch airlift reactor) configuration, due to the high localised hydrodynamic shear forces that occur in this type of configuration. The aim of this work was to observe the phenomenon of the aerobic granulation and to confirm the excellent removal efficiencies that can be achieved with this technology. In order to do that, a laboratory-scale plant, inoculated with activated sludge collected from a conventional WWTP, was operated for 64 days: 42 days as a SBAR and 22 days as a SBBC (sequencing batch bubble column). The performances of the pilot plant showed excellent organics removal. COD and BOD removal efficiencies were respectively, 93 and 94%; on the contrary, N-removal efficiency was extremely low (5%–45%). The granules dimensions increased during the whole experimentation; change of reactor configuration contributed to further improve this aspect. The experimental work confirmed the essential role of hydraulic settling time in the formation of aerobic granules and in the sludge settleability and the need to find an optimum between granule size and oxygen supply to achieve good N-removal efficiency.

scholarly journals Effect of temperatures and alternating anoxic/oxic sequencing batch reactor (SBR) operating modes on extracellular polymeric substances in activated sludge

2020 ◽  
Author(s):  
Hongwei Sun ◽  
Chenjian Cai ◽  
Jixue Chen ◽  
Chunyu Liu ◽  
Guangjie Wang ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Operating Modes ◽  
Nitrification Process ◽  
Main Component ◽  
Denitrification Process

Abstract In order to investigate the effect of temperatures and operating modes on extracellular polymeric substances (EPS) contents, three sequencing batch reactors (SBRs) were operated at temperatures of 15, 25, and 35 °C (R15 °C, R25 °C, and R35 °C, respectively), with two SBRs operated under alternating anoxic/oxic conditions (RA/O and RO/A, respectively). Results showed that higher contents of tightly bound EPS (TB-EPS) and total EPS appeared in R15 °C, while loosely bound EPS (LB-EPS) dominated in R35 °C. In all three kinds of EPS (LB-EPS, TB-EPS and total EPS) assessed, protein was the main component in R15 °C and R25 °C, while polysaccharides dominated in R35 °C. Moreover, compared with RO/A, RA/O was favorable for the production of the three kinds of EPS. Furthermore, three kinds of EPS and their components were augmented during the nitrification process, while they declined during the denitrification process under all conditions except for R35 °C.

Dynamic Modelling of Aerobic Granular Sludge Artificial Neural Networks

2017 ◽  
Vol 7 (3) ◽  
pp. 1568
Author(s):  
Nurazizah Mahmod ◽  
Norhaliza Abdul Wahab
Keyword(s):  
Neural Network ◽  
Batch Reactor ◽  
Dynamic Modelling ◽  
Oxygen Demand ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Batch Reactors ◽  
Neural Network Approach ◽  
Dynamic Neural Network ◽  
Promising Development

Aerobic Granular Sludge (AGS) technology is a promising development in the field of aerobic wastewater treatment system. Aerobic granulation usually happened in sequencing batch reactors (SBRs) system. Most available models for the system are structurally complex with the nonlinearity and uncertainty of the system makes it hard to predict. A reliable model of AGS is essential in order to provide a tool for predicting its performance. This paper proposes a dynamic neural network approach to predict the dynamic behavior of aerobic granular sludge SBRs. The developed model will be applied to predict the performance of AGS in terms of the removal of Chemical Oxygen Demand (COD). The simulation uses the experimental data obtained from the sequencing batch reactor under three different conditions of temperature (30˚C, 40˚C and 50˚C). The overall results indicated that the dynamic of aerobic granular sludge SBR can be successfully estimated using dynamic neural network model, particularly at high temperature.

Investigating the influence of elongated anaerobic feeding strategy on aerobic sludge granulation and characteristics in sequencing batch reactor

2014 ◽  
Vol 70 (2) ◽  
pp. 249-255 ◽  
Author(s):  
S. Sadri Moghaddam ◽  
M. R. Alavi Moghaddam
Keyword(s):  
Extracellular Polymeric Substances ◽  
Feeding Strategy ◽  
Batch Reactor ◽  
Volume Index ◽  
Feeding Strategies ◽  
Batch Reactors ◽  
Aerobic Granules ◽  
Sequencing Batch Reactors ◽  
Feeding Mode ◽  
Feed Strategy

In this research, two sequencing batch reactors (R1 and R2) were operated with different feeding strategies to investigate the effects of elongated anaerobic feeding mode on the granulation process. For this purpose, R1 was operated in a short-feed strategy (5 min) as a reference, whereas an extended anaerobic feeding of 85 min was applied in R2. Results showed that aerobic granules formed in R1 were denser and more uniform with lower sludge volume index than those formed in R2. Investigation of tightly bound extracellular polymeric substances (TB-EPS) showed that aerobic granules in R1 produced lower amounts of TB-EPS than those in R2. This was due to the bigger and more compact granules cultivated in R1 in comparison with looser structure granules in R2 with higher flocculent sludge percentage. The relative hydrophobicity of granules in both reactors was increased with culture time and reached about 63 and 65% at day 70 for R1 and R2, respectively. Moreover, no significant correlation between protein/polysaccharide ratio and hydrophobicity was found, which showed that protein in loosely bound extracellular polymer substances was not the predominant hydrophobic component. Considering the outcomes of this study, it can be concluded that the elongated anaerobic feeding strategy was unfavourable for cultivating aerobic granules.

Activated sludge behaviour in a batch reactor in the presence of antibiotics: study of extracellular polymeric substances

2010 ◽  
Vol 61 (12) ◽  
pp. 3147-3155 ◽  
Author(s):  
A. C. Avella ◽  
M. Essendoubi ◽  
J. N. Louvet ◽  
T. Görner ◽  
G. D. Sockalingum ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Extracellular Polymeric Substances ◽  
Batch Reactor ◽  
Size Exclusion ◽  
Batch Reactors ◽  
Municipal Sludge ◽  
Protection Mechanism ◽  
Toxic Agents ◽  
Exclusion Chromatography ◽  
Ft Ir

The influence of Erythromycin,Roxithromycin,Amoxicillin, Tetracycline and Sulfamethoxazole on municipal sludge in batch reactors was investigated. The study was focused on extracellular polymeric substances (EPS) as indicator of bacteria sensitivity to toxic agents. The EPS were analysed by UV-Vis and FT-IR spectroscopies and by size exclusion chromatography. It was found that Erythromycin and Roxithromycin induced a significant increase of bound EPS in flocs. This was attributed to a protection mechanism of the bacteria. Erythromycin was the only antibiotic which inhibited COD and nitrogen removal.

scholarly journals The Influence of Sulfate on Anaerobic Ammonium Oxidation in a Sequencing Batch Reactor

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3004
Author(s):  
Dominika Grubba ◽  
Joanna Majtacz
Keyword(s):  
Batch Reactor ◽  
Granular Sludge ◽  
Ammonium Nitrogen ◽  
Utilization Rate ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Sequencing Batch Reactors ◽  
Ammonium Oxidation ◽  
Anammox Activity ◽  
Anammox Process

Anaerobic ammonia-oxidizing bacteria have a more comprehensive metabolism than expected - there may be other electron acceptors that oxidize ammonium nitrogen under anaerobic conditions, in addition to the well-known nitrite nitrogen, one of which is sulfate in the sulfammox process. Sulfate-containing compounds are part of the medium for the anammox process, but their concentrations are not particularly high (0.2 g MgSO4 ∙ 7H2O/dm3 and 0.00625 g FeSO4/dm3). They can react to some extent with influent ammonium nitrogen. In this work, tests were carried out in two sequencing batch reactors with granular sludge. The first reactor (R1) operated in a 6 h cycle, and the concentration of the inflowing sulfate was kept at 44 mg/dm3∙d. The second reactor (R2) was operated until the 36th day in a 6 h cycle; the influencing concentration was 180 mg SO42−/dm3∙d from the 37th to 64th day in a 3 h cycle, with an influencing concentration of 360 mg SO42−/dm3∙d; and from the 65th to 90th day, the reactor was operated again in a 6 h cycle with an influencing concentration of 180 mg SO42−/dm3∙d. Along with the increased share of sulfate, both the ammonium utilization rate and specific anammox activity showed an increasing trend. As soon as the sulfate dosage was reduced, the ammonium utilization rate and specific anammox activity values dropped. Therefore, it can be concluded that sulfate-containing compounds contribute to the efficiency and rate of the anammox process.

scholarly journals Effect of Aeration Mode on Microbial Structure and Efficiency of Treatment of TSS-Rich Wastewater from Meat Processing

2020 ◽  
Vol 10 (21) ◽  
pp. 7414
Author(s):  
Piotr Jachimowicz ◽  
Agnieszka Cydzik-Kwiatkowska ◽  
Patrycja Szklarz
Keyword(s):  
Extracellular Polymeric Substances ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Batch Reactors ◽  
Ammonia Oxidizing Bacteria ◽  
Meat Processing ◽  
Intermittent Aeration ◽  
Microbial Structure ◽  
High Concentration ◽  
Next Generation Sequencing Ngs

The present study investigated the effect of aeration mode on microbial structure and efficiency of treatment of wastewater with a high concentration of suspended solids (TSS) from meat processing in sequencing batch reactors (R). R1 was constantly aerated, while in R2 intermittent aeration was applied. DNA was isolated from biomass and analyzed using next-generation sequencing (NGS) and real-time PCR. As a result, in R1 aerobic granular sludge was cultivated (SVI30 = 44 mL g−1 MLSS), while in R2 a very well-settling mixture of aerobic granules and activated sludge was obtained (SVI30 = 65 mL g−1 MLSS). Intermittent aeration significantly increased denitrification and phosphorus removal efficiencies (68% vs. 43%, 73% vs. 65%, respectively) but resulted in decomposition of extracellular polymeric substances and worse-settling properties of biomass. In both reactors, microbial structure significantly changed in time; an increase in relative abundances of Arenimonas sp., Rhodobacterace, Thauera sp., and Dokdonella sp. characterized the biomass of stable treatment of meat-processing wastewater. Constant aeration in R1 cycle favored growth of glycogen-accumulating Amaricoccus tamworthensis (10.9%) and resulted in 2.4 times and 1.4 times greater number of ammonia-oxidizing bacteria and full-denitrifiers genes in biomass, respectively, compared to the R2.

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