Breakage and growth towards a stable aerobic granule size during the treatment of wastewater

Verawaty, Marieska; Tait, Stephan; Pijuan, Maite; Yuan, Zhiguo; Bond, Philip L.

doi:10.1016/j.watres.2013.06.012

Cited by 84 publications

(36 citation statements)

References 26 publications

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“…From day 90 on, the granular size averagely stabilized at 0.76e0.78 mm, although the initial diameter of seed sludge was about 0.17 mm (Table 1). This observation is in agreement with the finding by Verawaty et al (2013) who reported that granules in the reactor equilibrated towards a common critical size of around 0.6e0.8 mm. MLSS and SVI 30 were determined to be 12e13 g/L and 22 ml/g after 60 days' cultivation.…”

Section: Formation and Characterization Of Aerobic Granulessupporting

confidence: 93%

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

et al. 2015

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Phosphorus (P) recovery from sewage sludge is necessary for a sustainable development of the environment and thus the society due to gradual depletion of non-renewable P resources. Aerobic granular sludge is a promising biotechnology for wastewater treatment, which could achieve P-rich granules during simultaneous nitrification and denitrification processes. This study aimed to disclose the changes in inorganic and organic P species and their correlation with P mobility and bio-availability in aerobic granules. Two identical square reactors were used to cultivate aerobic granules, which were operated for 120 days with influent ammonia nitrogen (NH₄-N) of 100 mg/L before day 60 and then increased to 200 mg/L during the subsequent 60 days (chemical oxygen demand (COD) was kept constant at 600 mg/L). The aerobic granules exhibited excellent COD removal and nitrification efficiency. Results showed that inorganic P (IP) was about 61.4-67.7% of total P (TP) and non-apatite inorganic P (NAIP) occupied 61.9-70.2% of IP in the granules. The enrichment amount of NAIP and apatite P (AP) in the granules had strongly positive relationship with the contents of metal ions, i.e. Fe and Ca, respectively accumulated in the granules. X-ray diffraction (XRD) analysis and solution index calculation demonstrated that hydroxyapatite (Ca₅(PO₄)₃(OH)) and iron phosphate (Fe₇(PO₄)₆) were the major P minerals in the granules. Organic P (OP) content maintained around 7.5 mg per gram of biomass in the aerobic granules during the 120 days' operation. Monoester phosphate (21.8% of TP in extract), diester phosphate (1.8%) and phosphonate (0.1%) were identified as OP species by Phosphorus-31 nuclear magnetic resonance (³¹P NMR). The proportion of NAIP + OP to TP was about 80% in the granules, implying high potentially mobile and bio-available P was stored in the nitrifying aerobic granules. The present results provide a new insight into the characteristics of P species in aerobic granules, which could be helpful for developing P removal and recovery techniques through biological wastewater treatment.

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Section: Formation and Characterization Of Aerobic Granulessupporting

confidence: 93%

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

et al. 2015

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“…Here, due to metabolic and physical limitations, the granule biofilm grows to a critical size, above this size the inner core of the granule is significantly weakened and these fracture into smaller granule particles (Verawaty et al, 2013). The findings from this study provide a greater understanding of the differences between these biofilm states, and this improved insight may contribute to better application and management of aerobic granular wastewater treatment processes.…”

Section: Accepted Articlementioning

confidence: 79%

Metagenomic and metaproteomic analyses of Accumulibacter phosphatis‐enriched floccular and granular biofilm

Barr

Dutilh

Skennerton

et al. 2015

Environmental Microbiology

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Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here we operated two laboratory-scale sequencing batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal (EBPR). Reactors formed two distinct biofilms, one floccular biofilm, consisting of small, loose, microbial aggregates, and one granular biofilm, forming larger, dense, spherical aggregates. Using metagenomic and metaproteomic methods we investigated the proteomic differences between these two biofilm communities, identifying a total of 2,022 unique proteins. To understand biofilm differences, we compared protein abundances that were statistically enriched in both biofilm states. Floccular biofilms were enriched with pathogenic secretion systems suggesting a highly competitive microbial community. Comparatively, granular biofilms revealed a high stress environment with evidence of nutrient starvation, phage predation pressure, and increased extracellular polymeric substance (EPS) and cell lysis. Granular biofilms were enriched in outer membrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter-enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability.

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“…During Step E, cell flocs approach each other in the case there exists an electrostatic attraction between positive and negative areas of cell flocs. Shear force shapes and densifies cell flocs (Step E) to become granular sludge, as shown in Step F. The mature granular sludge subsequently disintegrates after reaching a certain critical size, and then causes an overall reduction in granular size (Verawaty et al, 2013).…”

Section: Discussionmentioning

confidence: 95%

Effect of reactor height/diameter ratio and organic loading rate on formation of aerobic granular sludge in sewage treatment

Awang

Shaaban

2016

International Biodeterioration & Biodegradation

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Breakage and growth towards a stable aerobic granule size during the treatment of wastewater

Cited by 84 publications

References 26 publications

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

Metagenomic and metaproteomic analyses of Accumulibacter phosphatis‐enriched floccular and granular biofilm

Effect of reactor height/diameter ratio and organic loading rate on formation of aerobic granular sludge in sewage treatment

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