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.

scholarly journals Study on aerobic granular sludge formation in sequencing batch reactors for tapioca wastewater treatment

2013 ◽  
Vol 16 (1) ◽  
pp. 40-48
Author(s):  
Phuong Thi Thanh Nguyen ◽  
Phuoc Van Nguyen ◽  
Anh Cam Thieu
Keyword(s):  
Granular Sludge ◽  
Biomass Accumulation ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Aerobic Granules ◽  
Toxic Substances ◽  
Sequencing Batch Reactors

Aerobic granular sludge has attracted extensive interest of researchers since the 90s due to the advantages of aerobic granules such as good settling ability, high biomass accumulation, being resistant to high loads and being less affected by toxic substances. Studies, however, which have mainly been carried out on synthetic wastewater, cannot fully evaluate the actual ability of aerobic granules. Study on aerobic granular sludge was performed in sequencing batch reactors, using seeding sludge taken from anaerobic sludge and tapioca wastewater as a substrates. After 11 weeks of operation, the granules reached the stable diameter of 2- 3 mm at 3.7 kgCOD/m3.day organic loading rate. At high organic loads, in range of 1.6 - 5 kgCOD/m3.day, granules could treat effectively COD, N, P with performance of 93 – 97%; 65 – 79% and 80 – 95%, respectively.

scholarly journals Recovery of Stored Aerobic Granular Sludge and Its Contaminants Removal Efficiency under Different Operation Conditions

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiwei Zhao ◽  
Shuo Wang ◽  
Wenxin Shi ◽  
Ji Li
Keyword(s):  
Removal Efficiency ◽  
Granular Sludge ◽  
Aeration Rate ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Content Increase ◽  
Quick Recovery ◽  
Operation Conditions ◽  
Contaminants Removal ◽  
P Removal

The quick recovery process of contaminants removal of aerobic granular sludge (AGS) is complex, and the influencing factors are still not clear. The effects of dissolved oxygen (DO, air intensive aeration rate), organic loading rate (OLR), and C/N on contaminants removal characteristics of AGS and subsequently long-term operation of AGS bioreactor were investigated in this study. DO had a major impact on the recovery of AGS. The granules reactivated at air intensive aeration rate of 100 L/h achieved better settling property and contaminants removal efficiency. Moreover, protein content in extracellular polymeric substance (EPS) was almost unchanged, which demonstrated that an aeration rate of 100 L/h was more suitable for maintaining the biomass and the structure of AGS. Higher OLR caused polysaccharides content increase in EPS, and unstable C/N resulted in the overgrowth of filamentous bacteria, which presented worse NH4+-N and PO43−-P removal. Correspondingly, quick recovery of contaminants removal was accomplished in 12 days at the optimized operation conditions of aeration rate 100 L/h, OLR 4 g/L·d, and C/N 100 : 10, with COD, NH4+-N, and PO43−-P removal efficiencies of 87.2%, 86.9%, and 86.5%, respectively. The renovation of AGS could be successfully utilized as the seed sludge for the rapid start-up of AGS bioreactor.

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.

scholarly journals Performance of Aerobic Granular Sludge in Treating Soy Sauce Wastewater at Different Hydraulic Retention Time

2018 ◽  
Vol 7 (4.35) ◽  
pp. 564
Author(s):  
Hasnida Harun ◽  
Hazren A. Hamid ◽  
Norshuhaila Mohamed Sunar ◽  
Faridah Hanim Ahmad ◽  
Aznah Nor Anuar ◽  
...  
Keyword(s):  
Reaction Time ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Suspended Solid ◽  
Soy Sauce ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Reactor Performance ◽  
Dense Granules ◽  
Aerobic And Anaerobic

Aerobic granular sludge had shown its capability in treating soy sauce wastewater, but its reactor performance, granules properties and biokinetics in different hydraulic retention times (HRT) is still unknown. To ensure the reactor is performed in optimum condition, a judicially selection of HRT is important. The study was conducted in a high and slender column operated according to a sequential batch reactor (SBR) with a sequence of aerobic and anaerobic/anoxic reaction phases. Three different HRTs (8, 16, 24 h) and different anaerobic and aerobic reaction time were evaluated. In the study demonstrated the increase in HRT could reduce the organic loading rate (OLR) as well as biomass yield (Yobs, Y), endogenous decay rate (kd) and overall specific biomass growth rate (µoverall). It was observed a slight increase in the mixed liquor suspended solid (MLSS) and the granules mean size as the OLR decreased. Meanwhile, in the lowest HRT reactor, a narrow diameter range of aerobic granule from 3 to 100 µm was observed due to the development of small and dense granules. The HRT of 24h with aerobic and anaerobic/anoxic reaction time of 3.88 and 7.77h respectively is the SBR’s best performances due to the improvement of the aerobic granular physical properties.

Aerobic granular sludge: a promising technology for decentralised wastewater treatment

2006 ◽  
Vol 53 (9) ◽  
pp. 79-85 ◽  
Author(s):  
Z.H. Li ◽  
T. Kuba ◽  
T. Kusuda
Keyword(s):  
Sequencing Batch Reactor ◽  
Loading Rate ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Volume Index ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Fast Settling

In order to evaluate the characteristics of aerobic granular sludge, a sequencing batch reactor, feeding with synthetic wastewater at the organic loading rate of 8 kg COD/m3 d, was employed on the laboratory scale. Granules occurred in the reactor within 1 week after the inoculation from conventional flocculent sludge. Aerobic granular sludge was characterised by the outstanding settling properties and considerable contaminates removal efficiencies. The SVI30 values were in the range of 20 to 40 ml g−1. However, the sludge volume index of short settling time (e.g. SVI10 – 10 min) is suggested to describe the fast settling properties of aerobic granular sludge. The potential application in the decentralised system is evaluated from the point view of footprint and high bioactivity. The occurrence of sloughing, resulting from the outgrowth of filamentous organisms, would be responsible for the instability of aerobic granules. The starvation phase should therefore be carefully controlled for the maintenance and stability of aerobic granular sludge system.

Optimization of operation conditions for preventing sludge bulking and enhancing the stability of aerobic granular sludge in sequencing batch reactors

2014 ◽  
Vol 70 (9) ◽  
pp. 1519-1525 ◽  
Author(s):  
Jun Zhou ◽  
Hongyu Wang ◽  
Kai Yang ◽  
Fang Ma ◽  
Bin Lv
Keyword(s):  
Batch Reactor ◽  
Biomass Concentration ◽  
Granular Sludge ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Filamentous Bacteria ◽  
Operation Conditions ◽  
Sludge Bulking ◽  
The Stability

Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

scholarly journals Cultivation of aerobic granular sludge for the treatment of food-processing wastewater and the impact on membrane filtration properties

2020 ◽  
Author(s):  
H. Stes ◽  
M. Caluwé ◽  
L. Dockx ◽  
R. Cornelissen ◽  
P. De Langhe ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Feeding Strategy ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Suspended Solid ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Reactor Performance ◽  
Capillary Suction ◽  
The Impact

Abstract A lab-scale sequencing batch reactor was operated for approximately 300 days, divided into four periods based on the feeding strategy, to develop stable aerobic granular sludge (AGS) while treating chocolate processing wastewater. Application of a prolonged mixed anaerobic feeding was not sufficient to develop AGS and reach stable reactor performance. Through the application of a partially non-mixed and a partially mixed feeding strategy, the reactor performance was increased and stable AGS formation was established characterized by low diluted sludge volume index (D)SVI DSVI10,30) values of 78 ± 27 mL·g−1 and 52 ± 17 mL·g−1, respectively, and a capillary suction time/mixed liquor suspended solid value of 0.9 sec·(g·L−1)−1. The membrane bioreactor (MBR) filtration tests showed a reduction of the fouling rate (FR) and an increase of the sustainable flux (SF0.5) for AGS compared to flocs treating the same industrial wastewater. The SF0.5 (FR > 0.5 mbar·min−1) for the flocs was 10 L·(m2·h)−1 while for AGS the SF0.5 is higher than 45 L·(m2·h)−1 because the FR did not exceed 0.1 mbar·min−1. Additionally, the AGS showed reduced irreversible fouling tendencies due to pore blocking. Our results underline the need for an increased substrate gradient during anaerobic feeding for the development and long-term maintenance of AGS under minimum wash-out conditions. The AGS–MBR filtration performance also shows strong advantages compared to a floccular MBR system due to a high increase of the SF0.5 and reduced reversible and irreversible fouling.

Performance and Microbial Community of Aerobic Granular Sludge Bioreactor

2014 ◽  
Vol 522-524 ◽  
pp. 405-410
Author(s):  
Xia Zhao ◽  
Ji Min Shen ◽  
Zhong Lin Chen ◽  
Xiao Chun Wang
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Batch Reactor ◽  
Dynamic Balance ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Balance System ◽  
Microbial Species

Aerobic granular sludge was cultivated from activated-sludge in sequencing batch reactor. The change of physical properties and the effect of treatment of organic substance and microbial community were studied in the process of the different influent organic loading rate. The results showed that the formation process of aerobic granulation was rapid but the granular sludge was not stable and existed a disintegration-reunion dynamic balance system. The value of MLSS descended from 5.12g/L to 1.03g/L. The removal efficiency of NH4+-N decreased to 74.17% and total phosphorous (TP) removal efficiency maintained beyond 90% all the while. The CODCr removal was over 85% which higher than that of after adding in methanol, then reduced but had trend of rise to 31.89% at last. Microbial species in granulation were speculated by detecting polyhydroxyalkan- oates between granular sludge and activated sludge in the reactor. The results showed that microbial species of activated sludge are more diverse.

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