Strategies to improve aerobic granular sludge stability and nitrogen removal based on feeding mode and substrate

Yuan, Quan; Gong, Hui; Xi, Hu; Xu, Haipeng; Jin, Zhengyu; Ali, Nasir; Wang, Kaijun

doi:10.1016/j.jes.2019.04.006

Cited by 54 publications

(19 citation statements)

References 41 publications

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“…have great influence on the structural stability of AGS. It was found that when glucose was used as the sole carbon source, heterotrophic microorganisms would become the dominant bacteria, the rapid proliferation rate of which could significantly increase the sludge biomass, but this would also lead to excessive growth of filamentous bacteria causing structural instability of AGS; whereas, when acetate and succinate were used as mixed carbon sources, the cultured AGS was dominated by rod-shaped bacteria with higher structural stability and denitrification ability [13,35]. Metal cations and surface-negative charges of sludge can form a stable three-dimensional structure by binding or bridging, accelerating the granulation process of sludge and maintaining its stable structure [55].…”

Section: Reaction System 421 Substrate Conditionsmentioning

confidence: 99%

“…When the instability of AGS occurs, the sludge morphology will be degraded from dense particles to loose flocs, resulting in a significant impact on the biological activity and settling performance of sludge, which directly affects the effluent quality. Clearly, there are challenges in the instability of AGS particle structure [11][12][13]. Although the segregation of AGS might not be stopped, there may be an approach to deal with these problems to prolong the lifetime of the granules with stable structure in the future.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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: Reaction System 421 Substrate Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

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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“…These made the AGS technique made to be widely used in treatments of high-load industrial wastewater as well as sewage [9][10][11][12]. The stability of AGS is the most important issue in applying AGS-based process in various fields and is related many factors including the composition of influent wastewater, carbon to nitrogen (C/N) ratio, food to microorganisms (F/M) ratio, composition of extracellular polymeric substances (EPS), and rate and temperature of aeration [4,8,[13][14][15][16][17], among which, the C/N ratio of influent water is one of the most important factors for the growth of microorganism and biodegradation of nutrient salt [13,[18][19][20]. The application of AGS system, for example, into the treatment of wastewater treatment where the variance in wastewater is high was reported to be an important factor in decreased stability, degradation of granule and the growth of filamentous fungus [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Effects of carbon to nitrogen ratio on the performance and stability of aerobic granular sludge

Kim

Ahn

2020

Environmental Engineering Research

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The purpose of this study was to assess the nutrient salts removal efficiency and stability of the aerobic granular sludge (AGS) by change in C/N (carbon to nitrogen) ratio. The laboratory-scale experiments were performed to analyze the removal efficiencies for organic matter and contents of nitrogen, MLSS, sludge volume index, and extracellular polymeric substances (EPS) under C/N ratio conditions of 5.0, 10.0, 15.0, and 20.0. The microorganisms were observed using optical microscope and the microbial communities were analyzed using pyrosequencing. The increase in C/N ratio from 5.0 to 20.0 increased the organic matter and nitrogen removal efficiency to 95.9 and 79.1%, respectively. For the EPS contents, an influencing factor of granule stability, the polysaccharides to protein (PS/PN) ratio increased from 0.55 to 0.79. For the microbial community, the <i>Thauera</i> was the most common genus in ending phase occupying 63.7%. This microorganism is regarded as one contributing to organic matter degradation and improved production of EPS including AGS of microorganism, thus, may be an explanation of the results of this study such as increase in organic material in AGS and improvement of denitrification efficiency and contents of EPS with increase in C/N ratio.

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“…Some core genera have been identified in different AGS, including but not limited to Tetrasphaera, Sphingopyxis, Dechloromonas, Flavobacterium, Ohtaekwangia (Świątczak and Cydzik-Kwiatkowska, 2018), Meganema, Thauera, Paracoccus, Zoogloea (Szabó et al, 2017), Denitratisoma, Novosphingobium, Planctomyces, Ferruginibacter, Hyphomicrobium, Steroidobacter (Yuan et al, 2019). Furthermore, Ali et al reported that the bacterial compositions among different-sized aggregates are significantly different, and this dissimilarity increases with the increase in aggregate sizes, indicating an important role of species sorting in AGS systems (Ali et al, 2019).…”

Section: Sewage Millionaire-flocs In Wastewater Treatmentmentioning

confidence: 99%

Non-surface Attached Bacterial Aggregates: A Ubiquitous Third Lifestyle

Cai

2020

Front. Microbiol.

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Bacteria are now generally believed to adopt two main lifestyles: planktonic individuals, or surface-attached biofilms. However, in recent years medical microbiologists started to stress that suspended bacterial aggregates are a major form of bacterial communities in chronic infection sites. Despite sharing many similarities with surface-attached biofilms and are thus generally defined as biofilm-like aggregates, these non-attached clumps of cells in vivo show much smaller sizes and different formation mechanisms. Furthermore, ex vivo clinical isolates were frequently reported to be less attached to abiotic surfaces when compared to standard type strains. While this third lifestyle is starting to draw heavy attention in clinical studies, it has a long history in natural and environmental sciences. For example, marine gel particles formed by bacteria attachment to phytoplankton exopolymers have been well documented in oceans; large river and lake snows loaded with bacterial aggregates are frequently found in freshwater systems; multispecies bacterial “flocs” have long been used in wastewater treatment. This review focuses on non-attached aggregates found in a variety of natural and clinical settings, as well as some recent technical developments facilitating aggregate research. The aim is to summarise the characteristics of different types of bacterial aggregates, bridging the knowledge gap, provoking new perspectives for researchers from different fields, and highlighting the importance of more research input in this third lifestyle of bacteria closely relevant to our daily life.

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Strategies to improve aerobic granular sludge stability and nitrogen removal based on feeding mode and substrate

Cited by 54 publications

References 41 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

Effects of carbon to nitrogen ratio on the performance and stability of aerobic granular sludge

Non-surface Attached Bacterial Aggregates: A Ubiquitous Third Lifestyle

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