Causes and control of filamentous growth in aerobic granular sludge sequencing batch reactors

Liu, Yu; Liu, Qi-Shan

doi:10.1016/j.biotechadv.2005.08.001

Cited by 301 publications

(97 citation statements)

References 49 publications

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“…Unfavourable conditions like: wastewater composition, low substrate availability, dissolved oxygen deficiency, long solids retention time, nutrient deficiency and high temperature promote filamentous outgrowth [4,5]. It has been stated that low-levels of filamentous growth do not cause operational problems and may even stabilize the granule structure [4].…”

Section: Introductionmentioning

confidence: 99%

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Filamentous bacteria existence in aerobic granular reactors

Figueroa

Río

Campos

et al. 2014

Bioprocess Biosyst Eng

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Filamentous bacteria are associated to biomass settling problems in wastewater treatment plants. In systems based on aerobic granular biomass they have been proposed to contribute to the initial biomass aggregation process. However their development on mature aerobic granular systems has not been sufficiently studied. In the present research work filamentous bacteria were studied for the first time after long term operation (up to 300 days) of aerobic granular systems. Chloroflexi and Sphaerotilus natans have been observed in a reactor fed with synthetic wastewater. These filamentous bacteria could only come from the inoculated sludge. Thiothrix and Chloroflexi bacteria were observed in aerobic granular biomass treating wastewater from a fish canning industry. Meganema perideroedes was detected in a reactor treating wastewater from a plant processing marine products. As a conclusion the source of filamentous bacteria in these mature aerobic granular systems fed with industrial effluents was the incoming wastewater.

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Section: Introductionmentioning

confidence: 99%

“…However, in the case of filamentous overgrowth, the settleability of the aerobic granules becomes poor. Biomass washout and eventual disappearance of aerobic granules can subsequently occur [4].…”

Section: Introductionmentioning

confidence: 99%

Filamentous bacteria existence in aerobic granular reactors

Figueroa

Río

Campos

et al. 2014

Bioprocess Biosyst Eng

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Section: The Stability Of Aerobic Granular Sludgementioning

confidence: 70%

“…It has been reported that the overgrowth of filamentous microorganisms could result in the disintegration of granules [28]. However, excess filamentous bacteria were generally caused by lower F/M ratios in previous study [28]. This was due to low DO concentrations (<1.1 mg/L) having a strong positive effect on the proliferation of filaments [29].…”

Section: The Stability Of Aerobic Granular Sludgementioning

confidence: 75%

Effects of the Food-to-Microorganism (F/M) Ratio on N2O Emissions in Aerobic Granular Sludge Sequencing Batch Airlift Reactors

Guo

Zhang

Xie

et al. 2017

Water

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The present study investigated the effect of the food-to-microorganism (F/M) ratio on nitrous oxide (N 2 O) emissions in aerobic granular sludge sequencing batch airlift reactors. Three identical sequencing batch airlift reactors were fed with sodium acetate-based wastewater at different chemical oxygen demand (COD) concentrations, resulting in F/M ratios from 0.2 to 0.67 g COD/g SS. The results indicated that N 2 O emissions increased with an increase of the F/M ratio. N 2 O emissions at the high F/M ratio of 0.67 g COD/g SS were the highest (4.4 ± 0.94 mg/d). The main source of the high N 2 O emissions at the F/M ratio of 0.67 g COD/g SS was nitrifier denitrification, rather than heterotrophic denitrification, confirmed by the qPCR (quantitative real-time PCR) results. The heterotrophic denitrification was destroyed by the DO (dissolved oxygen) diffusing into the sludge particles with porous structures. This study offers theoretical support to study the N 2 O emissions in aerobic granular sludge, and can provide guidance for conducting risk assessment and enhancing our ability to predict N 2 O production in aerobic granular sludge at different F/M ratios.

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“…However, Li et al (2014) found Thiothrix as dominant filamentous bacteria in aerobic granules without negative impact on settling velocity. Several other studies also reported deterioration of settling properties of AGS, associated with overgrowth of filamentous bacteria (Liu and Liu 2006;Weissbrodt et al 2012). …”

Section: Resultsmentioning

confidence: 87%

The effects of carbon/phosphorus ratio on polyphosphate- and glycogen-accumulating organisms in aerobic granular sludge

Muszyński

Miłobędzka

2015

Int. J. Environ. Sci. Technol.

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A laboratory-scale granular sequencing batch reactor, fed with acetate, was operated at two different ratios of chemical oxygen demand to phosphorus-15:1 and 100:1. Smaller aerobic granules, but with better settleability, were obtained at the lower ratio. High ratio of phosphorus release to uptake of dissolved organic carbon (0.42 mol/mol) coincided with high percentage of polyphosphate-accumulating organisms (up to 70 % of all bacteria) and implied high metabolic activity of these bacteria. Polyphosphate-accumulating organisms belonged mainly to Accumulibacter and Tetrasphaera (46 and 23 %, respectively). Despite significant abundance, Tetrasphaera-related microorganisms were not detected by oligoprobes Actino-221 and Actino-658, but by broader oligoprobes Tet2-892 and Tet3-654. Low abundance (1 %) of Halomonas phosphatis indicated a minor role of these bacteria in the laboratory-scale reactor fed with synthetic wastewater. When the ratio of chemical oxygen demand to phosphorus was increased to 100:1, deterioration of settling properties was observed, caused by growth of filamentous organisms from Thiothrix/021N group. The higher ratio favoured Competibacter and was selected against all groups of polyphosphate-accumulating organisms. However, a significant percentage (10 %) of polyphosphate-accumulating organisms in the granular sludge with concomitant low ratio of phosphorus release to the uptake of dissolved organic carbon (0.01 mol/mol) suggested shift in the overall population metabolism. Under phosphorus limitation in wastewater, polyphosphate-accumulating organisms no longer synthesized poly-P and behaved as glycogen-accumulating organisms.

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Causes and control of filamentous growth in aerobic granular sludge sequencing batch reactors

Cited by 301 publications

References 49 publications

Filamentous bacteria existence in aerobic granular reactors

Filamentous bacteria existence in aerobic granular reactors

Effects of the Food-to-Microorganism (F/M) Ratio on N2O Emissions in Aerobic Granular Sludge Sequencing Batch Airlift Reactors

The effects of carbon/phosphorus ratio on polyphosphate- and glycogen-accumulating organisms in aerobic granular sludge

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