Impact of the filamentous fungi overgrowth on the aerobic granular sludge process

Sharaf, Ahmed; Guo, Bing; Liu, Yang

doi:10.1016/j.biteb.2019.100272

Cited by 14 publications

(17 citation statements)

References 43 publications

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“…As an influencing factor that is difficult to regulate, microbial community structure is regulated by substrate composition, temperature, pH, AGS granulation stage, and spatial location, which makes AGS show significant differences [14]. Appropriate amounts of filamentous bacteria can be used as a particle skeleton to trap free substances and promote the formation and stability of AGS, but excessive proliferation of filamentous bacteria will destroy its structural stability, resulting in loose sludge structure and flocculent [72]. If PAOs become the dominant bacteria in sludge granules, they can cause phosphorus precipitation in AGS.…”

Section: Temperaturementioning

confidence: 99%

Structural Characteristics of Aerobic Granular Sludge and Factors That Influence Its Stability: A Mini Review

Hou

Gan²,

Chen

et al. 2021

Water

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Current extensive research on aerobic granular sludge (AGS) largely focuses on improving its microbial biodiversity, settlement behavior, nitrogen and phosphorus removal efficiency, and shock load resistance. Great challenges that have to be faced are the bottleneck of slow-speed granulation and easy disintegration after granulation, which are key to the extended application of AGS technology. In the present review, the typical morphological structures of AGS are firstly summarized as well as the granulation model hypotheses, and then, we analyze the dominant microflora and their spatial distribution features. The influencing factors on particle structure stability are discussed thereafter on a macro and micro scale. Prospects and future research trends are also discussed based on the current study results for AGS technology.

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Section: Temperaturementioning

confidence: 99%

Structural Characteristics of Aerobic Granular Sludge and Factors That Influence Its Stability: A Mini Review

Hou

Gan²,

Chen

et al. 2021

Water

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“…However, the κg remained in considerably lower values, and the δ in higher ones (Figure 3 and Table 3), indicating a poor density and structural integrity of the filamentous aggregates formed under short periods, which could affect their stability in the long-term operation. The poor properties of filamentous granules have already been reported by Sharaf et al (2019), who indicates that the filamentous overgrowth affects the stability of the aggregates, even leading to the disruption of their structural integrity, causing their disintegration.…”

Section: Effect Of the Reduction Of The Famine Phase T Fam On The Stability Of Aerobic Granulesmentioning

confidence: 82%

“…The installation of decentralized greywater treatment systems to reclaim water for non-potable uses and nutrients, requires a set of low footprint and efficient technologies (Bajpai et al 2019). Greywater can be efficiently treated by sequencing batch reactors (SBR) with aerobic granular sludge (AGS), which is a biofilm that presents remarkable properties, such as high density (κg) and settling velocity (v s ), low sludge volume index and a structure which withstands toxics and organic shocks with high substrate (r s ) and oxygen (OUR) uptake rates (Sengar et al 2018;Sharaf et al 2019;Avila et al 2021). These characteristics allow an efficient solid-liquid separation, as well as the application of high volumetric exchange ratios (V er ) and short aeration and settling stages; key parameters to reduce the hydraulic retention time (HRT).…”

Section: Introductionmentioning

confidence: 99%

“…Filamentous overgrowth in AGS is a negative aspect that affects the stability and the operational efficiency of the SBR, as it leads to the increase on the granules size, producing fluffy and bulky aggregates with poor settling properties and density, which can be easily washed out from the system (Sharaf et al 2019). This phenomenon is produced by the adsorption and degradation of the particulated substrates at the surface of the granules during the aeration stage, leading to substrate diffusion gradients that result on the growth of filamentous and finger type structures.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the famine phase length on the properties of aerobic granular sludge treating greywater

Zamora

Fajardo-Ortiz

Moreno‐Andrade

et al. 2021

Water Science and Technology

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Sequencing batch reactors (SBR) treating high-strength greywater need an aerobic granular sludge (AGS) with good properties, such as a low sludge volume index (SVI) and high settling velocities and substrate uptake rates to yield short settling and aeration stages. To promote the formation of stable granular sludge, the length of the famine phase could be a key factor. In this regard, the effect of the duration of this variable on the AGS properties was assessed by comparing a gradual versus an abrupt reduction of the famine phase in two SBR treating greywater. The initial average famine phase of 3.3 h was gradually reduced to 0.3 h over 20 weeks in one reactor, and abruptly in another one. This condition induced filamentous outgrowth, as well as the deterioration on the properties of the sludge; being more accelerated the effect when the famine periods were abruptly shortened. In both cases the reduction on the famine periods induced increased organic loading rates, which led to degranulation events when it was higher than 2.5 g-COD g-VSS−1 d−1. Afterwards, the biomass adapted to this situation, by forming new small-filamentous aggregates with similar SVI to that of the stable AGS formed with the longest famine period.

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“…The change in domain-relative abundance signi es the evolution of microbial communities from seed sludge sample to aerobic granules, AGS control and AGS diatomite. A lot of researchers mentioned the shift of microbial community during granulation was due to the adjustment of the operational parameter in bioreactor system such as settling time, organic loading rate and aggregation characteristic [21,25,27].…”

Section: The Alpha Diversity Of the Microbial Communitymentioning

confidence: 99%

Microbial Community Shift and Role of Bacteria in Rapid Granulation By Using Diatomite

Basri

Anuar

Halim

2022

Preprint

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Aerobic granular sludge (AGS) technology is a promising biological method for modern wastewater treatment. However, granulation time have become a major issue for the application of AGS technology especially in low strength wastewater. Recent studies on granulation are focusing towards rapid start-up granulation process. Diatomite, a friable light-coloured sedimentary rock was introduces in this study to enhanced the granules formation. This study highlight the effect of diatomite towards the microbial community during the transformation of seed sludge until development of granules. DNA extraction and Metagenomic analysis was conducted with three samples (seed sludge, control AGS, AGS diatomite) to compare the microbial community. The microbial community analysis revealed the alpha diversity, phylum and class level, and the abundance of EPS producing bacteria of each bacteria samples respectively. Diatomite has a significant influence towards the microbial diversity (High Shannon index alpha diversity). Also, diatomite promotes the abundance of functional bacteria especially EPS producing bacteria, which seen as a crucial elements in granulation process.

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Impact of the filamentous fungi overgrowth on the aerobic granular sludge process

Cited by 14 publications

References 43 publications

Structural Characteristics of Aerobic Granular Sludge and Factors That Influence Its Stability: A Mini Review

Structural Characteristics of Aerobic Granular Sludge and Factors That Influence Its Stability: A Mini Review

Effect of the famine phase length on the properties of aerobic granular sludge treating greywater

Microbial Community Shift and Role of Bacteria in Rapid Granulation By Using Diatomite

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