The influence of settling time on the formation of aerobic granules

2004 ◽  
Vol 50 (10) ◽  
pp. 195-202 ◽  
Author(s):  
B.S. McSwain ◽  
R.L. Irvine ◽  
P.A. Wilderer
Keyword(s):  
Shear Force ◽  
Batch Reactor ◽  
Cation Exchange Resin ◽  
Granular Sludge ◽  
Community Analysis ◽  
Settling Time ◽  
Aerobic Granular Sludge ◽  
Extracellular Polysaccharides ◽  
Aerobic Granules ◽  
Pcr Products

Aerobic granular sludge, without the addition of carrier material, has only been reported in one suspended growth system, the Sequencing Batch Reactor (SBR) operated with short fill and settling periods. Recent studies have demonstrated that extracellular polysaccharides increased with the formation of aerobic granules, and that the shear force may stimulate production of these polysaccharides. In the study described herein, two SBRs were operated with the same shear force (air flow rate 275 L h−1) and two different settling times (2 and 10 min). Only the reactor with 2 min settling formed completely granular sludge, although granules were present in both reactors. Community analysis using 16S rRNA PCR products and DGGE showed that the communities diverged quickly after reactor start-up. For samples taken at steady-state, the granular population was more stable and less diverse than the flocculent reactor. EPS extraction of samples using cation exchange resin yielded similar values for aerobic granular sludge and previously reported anaerobic granules. While differences in the protein and TOC content between the flocculent and granular reactors increased appreciably as the sludge became more granular, the protein to polysaccharide ratio was relatively constant. The experiment confirmed previous theories that short settling times in SBRs select for granular sludge. The settling time results in granular sludge having a higher EPS protein content and a less diverse but more stable population.

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.

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.

THE IMPACT OF REACTOR HEIGHT/DIAMETER (H/D) RATIO ON AEROBIC GRANULAR SLUDGE (AGS) FORMATION IN SEWAGE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nik Azimatolakma Awang ◽  
Md. Ghazaly Shaaban
Keyword(s):  
Batch Reactor ◽  
Granular Sludge ◽  
Aeration Rate ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Aerobic Granules ◽  
Working Volume ◽  
Stable Conditions ◽  
The Impact ◽  
Reactor Height

Until now, the development of aerobic granules sludge (AGS) has been extensively reported using sequencing batch reactor (SBR) with reactor height/diameter (H/D) ratio of over 10. This is because the formation process of aerobic granules itself is depending upon the flowing trajectory inside reactor indulge by reactor height and superficial air velocity (SUAV). Thus, this study aims to determine effect of reactor H/D ratio on performance of AGS develop in two SBRS with equal working volume and organic loading rate (OLR). The two SBRs namely as SBR1 and SBR2 had a difference in reactor H/D ratio of 11.3 and 4.4, respectively. At an aeration rate of 4 L/min,  SUAV for SBR1 was two time higher than in SBR2, which were 1.33 cm/s and 0.7 cm/s, respectively. Thus, the SBR2 configuration condition seems unfavorable for development of compact aerobic granules. However, it was found that aerobic granules can be developed in both SBRs at an OLR as low as 0.12 kg CODs/m3 d and up to 0.49 kg CODs/m3 d. Mature aerobic granules were successfully developed after 49 and 89 days of formation, for Batch1 AGS and Batch2 AGS, respectively. At stable conditions, the highest CODs removal and SS effluent for Batch1 AGS and Batch2 AGS were more than 80% and below 26 mg/L, respectively. While effluent performance in both reactors was high, analysis on SVI30 indicated that SBR1 produced more sludge than SBR2. Compare to SBR1, at similar settling time of 15 min, SBR2 provide a short settling distance for biomass which was preferable in case of system breakdown due to shock OLR.

scholarly journals Powdered keramsite as unconventional method of AGS technology support in GSBR reactor with minimum-optimum OLR

2018 ◽  
Vol 44 ◽  
pp. 00024 ◽  
Author(s):  
Joanna Czarnota ◽  
Adam Masłoń ◽  
Monika Zdeb
Keyword(s):  
Batch Reactor ◽  
Granular Sludge ◽  
High Energy ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Aerobic Granules ◽  
Technology Support ◽  
Technological Parameters ◽  
The Stability ◽  
The Impact

Aerobic Granular Sludge (AGS) technology becomes a very competitive method to activated sludge system. Its main advantages include: high energy efficiency and low investment costs. Despite this fact, intensive research on biogranulation optimization are still carried out, both at laboratory and technical scale. In order to intensify the AGS technology, new methods of biogranulation and ways of improving the stability of aerobic granules are sought. So far, several studies have been conducted in this area, with using among others: chemical coagulants, dosage fragments of granules and powdered materials. The aim of this study was to evaluate the impact of powdered keramsite on the feasibility of rapid aerobic granulation in a GSBR reactor with a minimum-optimum organic loading rate (OLR). The research presents an effective way of cultivating stable aerobic granules in a Granular Sequencing Batch Reactor (GSBR) under specific technological parameters.

Dissolved oxygen as a key parameter to aerobic granule formation

2008 ◽  
Vol 58 (4) ◽  
pp. 781-787 ◽  
Author(s):  
B. S. McSwain Sturm ◽  
R. L. Irvine
Keyword(s):  
Dissolved Oxygen ◽  
Shear Force ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Batch Reactors ◽  
Aerobic Granules ◽  
High Shear ◽  
Sequencing Batch Reactors ◽  
Granule Formation ◽  
Substrate Removal

Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s−1. When less than 1 cm s−1 shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L−1 to 5 mg L−1, affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s−1, but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L−1, with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force.

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.

Strength characteristics of aerobic granular sludge

2012 ◽  
Vol 65 (2) ◽  
pp. 309-316 ◽  
Author(s):  
A. Nor-Anuar ◽  
Z. Ujang ◽  
M. C. M. van Loosdrecht ◽  
M. K. de Kreuk ◽  
G. Olsson
Keyword(s):  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Strength Analysis ◽  
Anaerobic Granular Sludge ◽  
Aerobic Granules ◽  
Sludge Flocs ◽  
Conventional Activated Sludge ◽  
Biomass Retention ◽  
Settling Characteristic ◽  
Fast Settling

Aerobic granular sludge has a number of advantages over conventional activated sludge flocs, such as cohesive and strong matrix, fast settling characteristic, high biomass retention and ability to withstand high organic loadings, all aspects leading towards a compact reactor system. Still there are very few studies on the strength of aerobic granules. A procedure that has been used previously for anaerobic granular sludge strength analysis was adapted and used in this study. A new coefficient was introduced, called a stability coefficient (S), to quantify the strength of the aerobic granules. Indicators were also developed based on the strength analysis results, in order to categorize aerobic granules into three levels of strength, i.e. very strong (very stable), strong (stable) and not strong (not stable). The results indicated that aerobic granules grown on acetate were stronger (high density: >150 g T SSL−1 and low S value: 5%) than granules developed on sewage as influent. A lower value of S indicates a higher stability of the granules.

Adsorption of Cd(ii) from aqueous solution by biogenic selenium nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (18) ◽  
pp. 15201-15209 ◽  
Author(s):  
Fanghui Yuan ◽  
Chao Song ◽  
Xuefei Sun ◽  
Linrui Tan ◽  
Yunkun Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sequencing Batch Reactor ◽  
High Efficiency ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Selenium Nanoparticles ◽  
Aerobic Granular Sludge ◽  
Biogenic Selenium Nanoparticles

BioSeNPs, which were produced by aerobic granular sludge in a sequencing batch reactor, could be used to remove cadmium from aqueous solution with high efficiency.

The SBR and its biofilm application potentials

2004 ◽  
Vol 50 (10) ◽  
pp. 1-10 ◽  
Author(s):  
P.A. Wilderer ◽  
B.S. McSwain
Keyword(s):  
Activated Sludge ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Waste Streams ◽  
Sludge Flocs ◽  
Biofilm Reactors ◽  
Volatile Organic ◽  
High Level ◽  
Slow Growing

Twenty plus years of experience, innovation, and research in the field of biological wastewater treatment and biofilm applications lead to the conclusion that biofilms are in many cases more desirable in reactors than suspended activated sludge. Biofilm reactors can provide very long biomass residence times even when the hydraulic influent loading is low. This makes them particularly suitable when treatment requires slow growing organisms with poor biomass yield or when the wastewater concentration is too low to support growth of activated sludge flocs. Regardless of the settling characteristics of biological aggregates or the hydraulic influent loading the metabolic activity in the reactor can be maintained at a high level. This paper reviews the application of biofilms in sequencing batch reactor (SBR) systems to treat non-readily biodegradable substrates, volatile organic waste constituents, complex waste streams requiring co-metabolism, and particulate wastewaters. Recent research using the SBR to form aerobic granular sludge as a special application of biofilms is also discussed.

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