Aerobic granular sludge in a sequencing batch reactor

Morgenroth, Eberhard; Sherden, T.; Loosdrecht, M.C.M. van; Heijnen, Joseph J.; Wilderer, P.A.

doi:10.1016/s0043-1354(97)00216-9

Cited by 537 publications

(272 citation statements)

References 11 publications

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“…This biomass accumulation could allow some bacteria, such as methanogens, to be held in the reactor for periods greater than the hydraulic detention time. Methanogenic bacteria are known to form dense granules with hydrogen-producing bacteria, and these granules have been well characterized in previous studies (Dudley et al, 1993;Schmidt and Ahring, 1996;Yun and Tay, 1997;Morgenroth et al, 1997). However, the properties of flocs formed by hydrogen-producing bacteria alone, in continuous culture systems, has not been well studied.…”

Section: Introductionmentioning

confidence: 99%

Physical and hydrodynamic properties of flocs produced during biological hydrogen production

Zhang¹,

Li²,

Oh³

et al. 2004

Biotech & Bioengineering

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Dense flocs readily form in continuous culture bioreactors used for hydrogen production, but the fractal and hydrodynamic properties of these flocs have not been previously analyzed. We therefore examined the size distribution, fractal dimension, and hydrodynamic properties of flocs formed in a continuous flow, well-mixed reactor treating synthetic wastewater at a fixed condition of a 4.5 h hydraulic detention time (23jC, pH 5.5). The reactor was operated for a total of 3 months at three different organic loading rates (27, 53, and 80 g-COD/L-d) with influent glucose concentrations of 5, 10, and 15 g-COD/L. At all three loading rates the removal of glucose was nearly complete (98.6 -99.4%) and biomass was produced in proportion to the organic loading rate (0.86 F 0.11, 2.40 F 0.26, and 4.59 F 1.55 g/L of MLVSS in the reactor). Overall conversion efficiencies of glucose to hydrogen, evaluated on the basis of a maximum of 4 mol-H 2 /molglucose, increased with organic loading rates in the order 17.7%, 23.1%, and 25.6%. The gas contained 56.1 F 4.9% hydrogen, with the balance as carbon dioxide. No methane gas was detected. Under these conditions, flocs were produced with mean sizes that increased with organic loading, in the order 0.12 cm (5 g-COD/L), 0.35 cm (10 g-COD/L), and 0.58 cm (15 g-COD/L). As the average floc size increased, the flocs became on average denser and less fractal, with fractal dimensions increasing from 2.11 F 0.17 to 2.48 F 0.13. Floc porosities ranged from 0.75 -0.96, and resulted in aggregate densities that allowed little intra-aggregate flow through the floc. As a result, average settling velocities were not appreciably larger than those predicted by Stokes' law for spherical, impermeable flocs. Our results demonstrate that dense, relatively impermeable flocs are produced in biohydrogen reactors that have settling properties in reasonable agreement with Stokes' law. B 2004 Wiley Periodicals, Inc.

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Section: Introductionmentioning

confidence: 99%

Physical and hydrodynamic properties of flocs produced during biological hydrogen production

Zhang¹,

Li²,

Oh³

et al. 2004

Biotech & Bioengineering

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“…1 (A)). In the meantime, SVI 30 in the both reactors maintained at around 45 ml/g ( Fig. 1 (B)), indicating good settling ability of the nitrifying granular sludge.…”

Section: The Cultivation Of the Nitrifying Granulesmentioning

confidence: 84%

“…In this study, it was found that the size of the nitrifying granules was increased with the fast loading increasing in the feed, which could be a positive responds of the nitrifying granules to the disadvantageous environment, i.e., the stepwise accumulated FA and FNA in the bulk liquid. The high growth rate of bacterial strains was widely reported to encourage proliferation of microbes, which may cause a rapid increase in size of the granules with a loose structure and low density [30], [31]. In the meantime, the size of the micro-colonies was reported to be able to determine whether fragmentation took place under the shear conditions applied and that whether this shear could erode or further fragmentation [32].…”

Section: Discussionmentioning

confidence: 99%

Formation and Stability of Nitrifying Granules under High Loading Rates

Wang¹,

Chen²,

Nie³

et al. 2016

IPCBEE

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Abstract. Nitrifying granules are generally believed to have high nitrification ability due to the immobilization of large quantities of nitrifying bacteria with low growth rate. However, high loading rate is normally not recommended for nitrifying granules due to the high inhibition statue. In this study, nitrifying granules, able to treat ammonia nitrogen as high as 1000 mg N/L (2 kg N/m 3 ·d), were cultivated in the laboratory scale sequencing batch reactor. During around 200-day operation, the granules exhibited good performance with 99% ammonia removal efficiency. In the meantime, MLSS increased from initial 6 g/L to the final 10 g/L, and the value of SVI 30 decreased from around 100 to 15 ml/g. However, it was observed that the nitrifying granules gradually disintegrated into small aggregates with mean size decreased from 286 to 138 μm from the operation day 50 to 120, after which they gradually recovered by themselves with increased mean size of 235 μm at the end of the operation. Notably, this disintegration did not compromise performance and characteristics of the nitrifying granules. These results demonstrated that nitrifying granules may have the capability to undertake ammonia loading rates as high as 1000 mg N/L with good self-healing ability, which make the process more stable and promising in practice.

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“…Liu and Tay (2004) and Maximova and Dahl (2006) provided an up to date summary of the current understanding towards the bioaggregation processes. Granular sludge was first described for strictly anaerobic systems in 1980 (Lettinga et al, 1980) and only by the late 1990s had the formation and application of aerobic granules been reported (Morgenroth et al, 1997, Beun et al, 1999, Dangcong et al, 1999. The anaerobic granulation technology exhibited several drawbacks that included a long start-up period, a relatively high operating temperature, unsuitability for low strength organic wastewater, and low efficiency in the removal of nutrients (N and P) from wastewater.…”

Section: Introductionmentioning

confidence: 99%

“…Compact structured, biologically efficient aerobic sludge granules with wide diverse microbial species and excellent settling capabilities have been developed in sequencing batch reactors (SBR) (Morgenroth et al, 1997;Beun et al, 1999;Tay et al, 2001a;Yang et al, 2003;Tay, 2004, Adav et al, 2007a). Formation by self immobilization of bacteria as hypothesized by several researchers (Kim et al, 2004;McSwain et al, 2004a;Qin et al, 2004a,b;Wang et al, 2004;Hu et al, 2005;Liu et al, 2005), the aerobic granules were densely packed microbial aggregates and their densities were much higher than that of conventional activated sludge.…”

Section: Introductionmentioning

confidence: 99%

Biotechnology advances

1998

Biotechnology Advances

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Aerobic granulation, a novel environmental biotechnological process, was increasingly drawing interest of researchers engaging in work in the area of biological wastewater treatment. Developed about one decade ago, it was exciting research work that explored beyond the limits of aerobic wastewater treatment such as treatment of high strength organic wastewaters, bioremediation of toxic aromatic pollutants including phenol, toluene, pyridine and textile dyes, removal of nitrogen, phosphate, sulphate and nuclear waste and adsorption of heavy metals. Despite this intensive research the mechanisms responsible for aerobic granulation and the strategy to expedite the formation of granular sludge, and effects of different operational and environmental factors have not yet been clearly described. This paper provides an up-to-date review on recent research development in aerobic biogranulation technology and applications in treating toxic industrial and municipal wastewaters. Factors affecting granulation, granule characterization, granulation hypotheses, effects of different operational parameters on aerobic granulation, response of aerobic granules to different environmental conditions, their applications in bioremediations, and possible future trends were delineated. The review attempts to shed light on the fundamental understanding in aerobic granulation by newly employed confocal laser scanning microscopic techniques and microscopic observations of granules.

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Aerobic granular sludge in a sequencing batch reactor

Cited by 537 publications

References 11 publications

Physical and hydrodynamic properties of flocs produced during biological hydrogen production

Physical and hydrodynamic properties of flocs produced during biological hydrogen production

Formation and Stability of Nitrifying Granules under High Loading Rates

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