Aerobic granulation in a mechanical stirred SBR: treatment of low organic loads

2011 ◽  
Vol 64 (1) ◽  
pp. 155-161 ◽  
Author(s):  
A. Mosquera-Corral ◽  
B. Arrojo ◽  
M. Figueroa ◽  
J. L. Campos ◽  
R. Méndez

Aerobic granular sludge was produced in a sequencing batch reactor (SBR) characterized by a height to diameter ratio of 2.5 and the use of mechanical stirring. Compact and regular aerobic granules of up to 1.75 mm of average diameter were formed in the reactor with an organic loading rate of 1.75 kg COD/(m3 d). Settling properties of the obtained aggregates were: sludge volumetric index of 30–40 mL/g VSS and settling velocity higher than 8 m/h. The effects of different carbon to nitrogen ratios (TOC/N) in the feeding on the organic matter oxidation and nitrification process were studied. The concentration of organic matter in the feeding was stepwise reduced (from 190.0 to 37.5 mg TOC/L) and ammonium increased (from 25 to 50 mg NH4+-N/L). TOC/N ratios of 7.50, 3.00, 1.50 and 0.75 g/g in the feeding were tested. The TOC removal percentage was around 80–95% during the whole operational period and the N removal percentages obtained in the reactor were up to 40%, however, physical properties of the granules were not maintained.

2011 ◽  
Vol 63 (9) ◽  
pp. 1808-1814 ◽  
Author(s):  
M. Figueroa ◽  
A. Val del Río ◽  
J. L. Campos ◽  
A. Mosquera-Corral ◽  
R. Méndez

Aerobic granular sludge grown in a sequential batch reactor was proposed as an alternative to anaerobic processes for organic matter and nitrogen removal from swine slurry. Aerobic granulation was achieved with this wastewater after few days from start-up. On day 140 of operation, the granular properties were: 5 mm of average diameter, SVI of 32 mL (g VSS)−1 and density around 55 g VSS (Lgranule)−1. Organic matter removal efficiencies up to 87% and nitrogen removal efficiencies up to 70% were achieved during the treatment of organic and nitrogen loading rates (OLR and NLR) of 4.4 kg COD m−3 d−1 and of 0.83 kg N m−3 d−1, respectively. However, nitrogen removal processes were negatively affected when applied OLR was 7.0 kg COD m−3 d−1 and NLR was 1.26 kg N m−3 d−1. The operational cycle of the reactor was modified by reducing the volumetric exchange ratio from 50 to 6% in order to be able to treat the raw slurry without dilution.


2009 ◽  
Vol 60 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
S. López–Palau ◽  
J. Dosta ◽  
J. Mata-Álvarez

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.


2004 ◽  
Vol 49 (11-12) ◽  
pp. 41-46 ◽  
Author(s):  
N. Schwarzenbeck ◽  
R. Erley ◽  
P.A. Wilderer

Aerobic granular sludge was successfully cultivated in a lab-scale SBR-system treating malting wastewater with a high content of particulate organic matter (0.9 gTSS/L). At an organic loading rate (CODtotal) of 3.4 kg/(m3·d) an average removal efficiency of 50% in CODtotal and 80% in CODdissolved was achieved. Fractionation of the COD by means of particle size showed that particles with a diameter less than 25–50 μm could be removed at 80% efficiency, whereas particles bigger than 50 μm were only removed at 40% efficiency. Tracer experiments revealed a dense sessile protozoa population covering the granules. The protozoa appeared to be responsible for primary particle uptake from the wastewater.


2016 ◽  
Vol 1 (2) ◽  
pp. 10 ◽  
Author(s):  
Hong Liang ◽  
Xue Li ◽  
Shanshan Wang ◽  
Dawen Gao

A sequencing batch reactor (SBR) was used to study the effect of carbon source (C6H12O6 and CH3COONa) and C/N ratio (C/N=4:1 and C/N=7:1) on the production of nitrous oxide (N2O) in the process of simultaneous nitrifica-tion and denitrification via nitrite (short-cut SND) by aerobic granular sludge and the removal efficiency of nitrogen under low dissolved oxygen (DO). The results showed that short-cut SND occurred in this system, and the removal ef-ficiency of total nitrogen (TN) at C6H12O6 and CH3COONa were 28.93 % and 41.19 %, respectively. However, the production of N2O significantly increased when CH3COONa was used as a carbon source. In addition, the rate of N2O release when CH3COONa was a carbon source was 8.34 times the rate when C6H12O6 was the carbon source. With the increase of C/N, removal rate of TN and the efficiency of the short-cut SND were increased. The removal efficiency of TN at C/N=7:1 was 90.33%, which was 2.19 times at C/N=4:1. The percentage of short-cut SND at C/N=4:1 and C/N=7:1 were 87.47% and 95.97%, respectively. The release rate of N2O from the original 1.14 mg/(g • min) decreased to 0.10 mg/(g • min) after increased the C/N from 4:1 to 7:1.


2001 ◽  
Vol 43 (3) ◽  
pp. 19-26 ◽  
Author(s):  
T. Etterer ◽  
P. A. Wilderer

A sequencing batch reactor (SBR) was used to investigate the generation of different granules cultured under aerobic and alternating anaerobic/aerobic conditions. The reactor was fed with synthetic wastewater. A substrate loading rate of 3.6 kg COD/ (m3 day) was applied. Granules of heterotrophic microorganisms were formed. After the first experimental period of 8 weeks the average granule diameter was 3.2 mm. In the second period, alternating anaerobic/aerobic conditions were applied to form granular sludge with an average diameter of 3.0 mm. An isopycnic centrifugation procedure was used to determine the characteristic density of the aerobic granular sludge. The average density of the granular sludge was 1.044 g/ml and 1.048 g/ml, respectively. In free-settling tests the final settling velocity of single aggregates was examined to estimate porosity. Settling velocities up to 2.0 cm/s could be measured. Calculations based on the experimental results showed an average granula porosity of 72% for the first run and 65% average porosity for the second run. This paper indicates the validity of general assumptions in free-settling tests.


2014 ◽  
Vol 955-959 ◽  
pp. 339-342 ◽  
Author(s):  
Xin Gang Wang ◽  
Bing Lin ◽  
Yu Bin Tang ◽  
Hai Feng Chen

The aerobic granular sludge (AGS) was used to remove pollutants (COD, NH3-N, TN and TP) in wastewater under different salinity in a sequencing batch reactor (SBR). The results show that: the salinity has a significant impact on the removal of COD and TN, and the removal rate declines to 60% and 56% respectively when the water salinity rises from 5g/L to15g/L. The NH3-N removal is not much affected by the salinity, and the average removal rate is 75%. TP removal rate changes little at low-salted environment (the salinity less than 10g/L), however, the rate declines heavily when the salinity gets more than 10g/L, 70% in 10g/L and 57% in 15g/L.


2018 ◽  
Vol 7 (4.35) ◽  
pp. 564
Author(s):  
Hasnida Harun ◽  
Hazren A. Hamid ◽  
Norshuhaila Mohamed Sunar ◽  
Faridah Hanim Ahmad ◽  
Aznah Nor Anuar ◽  
...  

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.


2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nik Azimatolakma Awang ◽  
Md. Ghazaly Shaaban

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.


2018 ◽  
Vol 44 ◽  
pp. 00024 ◽  
Author(s):  
Joanna Czarnota ◽  
Adam Masłoń ◽  
Monika Zdeb

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.


2006 ◽  
Vol 53 (9) ◽  
pp. 79-85 ◽  
Author(s):  
Z.H. Li ◽  
T. Kuba ◽  
T. Kusuda

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.


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