Settling behaviour of aerobic granular sludge

Aerobic granular sludge (AGS) technology has been extensively studied recently to improve sludge settling and behaviour in activated sludge systems. The main advantage is that aerobic granular sludge (AGS) can settle very fast in a reactor or clarifier because AGS is compact and has strong structure. It also has good settleability and a high capacity for biomass retention. Several experimental works have been conducted in this study to observe the settling behaviours of AGS. The study thus has two aims: (1) to compare the settling profile of AGS with other sludge flocs and (2) to observe the influence of mechanical mixing and design of the reactor to the settleability of AGS. The first experimental outcome shows that AGS settles after less than 5 min in a depth of 0.4 m compared to other sludge flocs (from sequencing batch reactor, conventional activated sludge and extended aeration) which takes more than 30 min. This study also shows that the turbulence from the mixing mechanism and shear in the reactor provides an insignificant effect on the AGS settling velocity.

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Strength characteristics of aerobic granular sludge

Water Science & Technology ◽

10.2166/wst.2012.837 ◽

2012 ◽

Vol 65 (2) ◽

pp. 309-316 ◽

Cited By ~ 23

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.

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The SBR and its biofilm application potentials

Water Science & Technology ◽

10.2166/wst.2004.0596 ◽

2004 ◽

Vol 50 (10) ◽

pp. 1-10 ◽

Cited By ~ 27

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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Simulation of Aerobic Granular Sludge Process Efficiency

Revista de Chimie ◽

10.37358/rc.17.8.5752 ◽

2017 ◽

Vol 68 (8) ◽

pp. 1723-1725

Author(s):

Elena Elisabeta Manea ◽

Costel Bumbac ◽

Olga Tiron ◽

Razvan Laurentiu Dinu ◽

Valeriu Robert Badescu

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Batch Reactor ◽

Granular Sludge ◽

Process Efficiency ◽

Aerobic Granular Sludge ◽

Organic Load ◽

Batch Reactors ◽

Conventional Activated Sludge ◽

Pollutants Removal

Using aerobic granular sludge for wastewater treatment has multiple advantages compared to conventional activated sludge systems, most important being the ability of simultaneous removal of the pollutants responsible for eutrophication: organic load, compounds of nitrogen (NH4+; NO3-) and phosphorus (PO43-). The advantages are currently exploited for developing the next generation of wastewater treatment systems while the identified limitations are approached by experimental and theoretical researches worldwide. The aim of the study consists in evaluating the possibility of predicting the system�s response to different changes in the influent wastewater loadings. The paper presents simulations results backed up by experimental data for pollutants removal efficiencies evaluation for a sequential batch reactor (SBR) with aerobic granular sludge. The mathematical model is based on the activated sludge model no. 3, which was updated by considering the simultaneous biological nitrification (NH4+NO3) and denitrification (NO3-N2) processes, thus complying with the biochemical reactions occurring in aerobic granular sludge sequential batch reactors. The model developed was validated by the experimental results obtained on a laboratory scale SBR monitored for over a month.

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Sequencing batch reactor (SBR) as optimal method for production of granular activated sludge (GAS) – fluid dynamic investigations

Water Science & Technology ◽

10.2166/wst.2007.253 ◽

2007 ◽

Vol 55 (8-9) ◽

pp. 151-158 ◽

Cited By ~ 6

Author(s):

B.E. Zima ◽

L. Díez ◽

W. Kowalczyk ◽

A. Delgado

Keyword(s):

Multiphase Flow ◽

Activated Sludge ◽

Sequencing Batch Reactor ◽

Fluid Dynamic ◽

Batch Reactor ◽

Aerobic Condition ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Major Influence ◽

Optimal Method

Fluid dynamic investigations of multiphase flow (fluid, air, granules) in a sequencing batch reactor (SBR) are presented. SBR can be considered as an attractive technology for cultivation of granular activated sludge (GAS). Granulation is a complicated process and its mechanism is not fully understood yet. Many factors influence the formation and structure of aerobic granular sludge in a bioreactor. Extracellular polymer substances (EPS) and superficial gas velocity (SGV) play a crucial role for granules formation. Additionally, it is supposed that EPS production is stimulated by mechanical forces. It is also assumed that hydrodynamic effects have a major influence on the formation, shape and size of GAS in SBR under aerobic condition. However, the influence of stress on granulation is poorly investigated. Thus, in the present paper, fluid dynamic investigations of multiphase flow in a SBR, particularly effect of normal and shear strain, are reported. In order to analyse multiphase flow in the SBR, optical in-situ techniques with particle image velocimetry (PIV) and particle tracking velocimetry (PTV) are implemented. Obtained results show a characteristic flow pattern in a SBR. It is pointed out that additional effects like particle-wall collisions, inter particle collisions, erosion can also affect significantly granules formation.

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Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

E3S Web of Conferences ◽

10.1051/e3sconf/20183402022 ◽

2018 ◽

Vol 34 ◽

pp. 02022

Author(s):

Azlina Mat Saad ◽

Farrah Aini Dahalan ◽

Naimah Ibrahim ◽

Sara Yasina Yusuf ◽

Siti Aqlima Ahmad ◽

...

Keyword(s):

Industrial Wastewater ◽

Sequencing Batch Reactor ◽

Settling Velocity ◽

Batch Reactor ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

X Ray ◽

Conventional Activated Sludge ◽

Physiological Structure ◽

Granulation Technology

Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic – anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

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Microbial diversity differences within aerobic granular sludge and activated sludge flocs

Applied Microbiology and Biotechnology ◽

10.1007/s00253-012-4472-7 ◽

2012 ◽

Vol 97 (16) ◽

pp. 7447-7458 ◽

Cited By ~ 67

Author(s):

M-K H. Winkler ◽

R. Kleerebezem ◽

L. M. M. de Bruin ◽

P. J. T. Verheijen ◽

B. Abbas ◽

...

Keyword(s):

Activated Sludge ◽

Microbial Diversity ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Sludge Flocs

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Removal of crystal violet from aqueous solutions using an aerobic granular sludge system

Romanian Journal of Ecology & Environmental Chemistry ◽

10.21698/rjeec.2021.107 ◽

2021 ◽

Vol 3 (1) ◽

pp. 55-60

Author(s):

Costel Bumbac ◽

◽

Elena Elisabeta Manea ◽

Olga Tiron

Keyword(s):

Activated Sludge ◽

Respiration Rate ◽

Crystal Violet ◽

Treatment Cycle ◽

Granular Sludge ◽

Inhibitory Effect ◽

Aerobic Granular Sludge ◽

Specific Test ◽

Conventional Activated Sludge ◽

The Matrix

The paper presents a set of comparative tests to evaluate the inhibitory effect of crystal violet on the respiration rate of microorganisms in conventional activated sludge and aerobic granular sludge. The tests were performed in similar conditions with the only variable of the type of sludge tested. The results emphasized that the aerobic granular sludge is less susceptible to the toxicity induced by crystal violet. The concentration of crystal violet that inhibits by 50% (CE50) the respiration rate of sludge microorganisms was determined to be, for the specific test conditions, 22.39 mg/L for the conventional activated sludge and 33.88 mg/L for the aerobic granular sludge. The paper also assesses the biodegradability potential of crystal violet from aqueous solution, in the presence of sodium acetate as co-substrate in a lab-scale sequential biological reactor with aerobic granular sludge. The experiments showed that most of the crystal violet is being initially absorbed in the matrix of the granules during the first minutes and subsequently is being removed with efficiencies above 95% within a treatment cycle of 8 hours.

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