A novel granular sludge sequencing batch reactor for removal of organic and nitrogen from wastewater

Yang, Shu-Fang; Tay, Joo‐Hwa; Liu, Yu

doi:10.1016/j.jbiotec.2003.07.007

Cited by 129 publications

(81 citation statements)

References 15 publications

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“…Formation of the three-dimensional structure of the granules is mediated through a sequence of events [93] and are primarily composed of mixed species microbial consortia held together in a matrix of their own EPS along with other embedded particles [94][95][96][97][98][99]. As in other microbial aggregates, such as biofi lms and biofl ocs, the EPS produced in biogranules are also composed of variable amounts of proteins, polysaccharides, nucleic acids, humic-like substances, lipids and glycoproteins, but the content of EPS in biogranules have been found to be much higher than that of biofl ocs and biofi lms [3].…”

Section: Biogranules and Metal Removalmentioning

confidence: 99%

Microbial extracellular polymeric substances: central elements in heavy metal bioremediation

2008

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Extracellular polymeric substances (EPS) of microbial origin are a complex mixture of biopolymers comprising polysaccharides, proteins, nucleic acids, uronic acids, humic substances, lipids, etc. Bacterial secretions, shedding of cell surface materials, cell lysates and adsorption of organic constituents from the environment result in EPS formation in a wide variety of free-living bacteria as well as microbial aggregates like biofi lms, biofl ocs and biogranules. Irrespective of origin, EPS may be loosely attached to the cell surface or bacteria may be embedded in EPS. Compositional variation exists amongst EPS extracted from pure bacterial cultures and heterogeneous microbial communities which are regulated by the organic and inorganic constituents of the microenvironment. Functionally, EPS aid in cell-to-cell aggregation, adhesion to substratum, formation of fl ocs, protection from dessication and resistance to harmful exogenous materials. In addition, exopolymers serve as biosorbing agents by accumulating nutrients from the surrounding environment and also play a crucial role in biosorption of heavy metals. Being polyanionic in nature, EPS forms complexes with metal cations resulting in metal immobilization within the exopolymeric matrix. These complexes generally result from electrostatic interactions between the metal ligands and negatively charged components of biopolymers. Moreover, enzymatic activities in EPS also assist detoxifi cation of heavy metals by transformation and subsequent precipitation in the polymeric mass. Although the core mechanism for metal binding and / or transformation using microbial exopolymer remains identical, the existence and complexity of EPS from pure bacterial cultures, biofi lms, biogranules and activated sludge systems differ signifi cantly, which in turn affects the EPS -metal interactions. This paper presents the features of EPS from various sources with a view to establish their role as central elements in bioremediation of heavy metals.

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Section: Biogranules and Metal Removalmentioning

confidence: 99%

Microbial extracellular polymeric substances: central elements in heavy metal bioremediation

2008

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“…Compared to conventional activated sludge flocs, aerobic granulation has several advantages, such as excellent settleability (Yang et al, 2003), ability to withstand high organic load (Adav et al, 2010), dense and strong microbial structure, and tolerance to toxicity (Adav et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Microbial community and N removal of aerobic granular sludge at high COD and N loading rates

Zhao

Huang

Zhao

et al. 2013

Bioresource Technology

132

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“…While granules were first reported in an upflow anaerobic sludge blanket bioreactor two decades ago (Lettinga et al, 1980), recent research efforts have been dedicated to the study of aerobic granules (Morgenroth et al, 1997;Beun et al, 1999;Peng et al, 1999;Etterer and Wilderer, 2001;Tay et al, 2001). Aerobic granules cultivated in synthetic wastewater bioreactors have been reported to achieve COD and/or N removal (Tay et al, 2002;Liu et al, 2003;Yang et al, 2003) and, in some cases, P removal (Dulekgurgen et al, 2003;Lin et al, 2003). Aerobic granules can be described as compact and dense aggregates of microbial origin with an approximately spherical external appearance that do not coagulate under reduced hydrodynamic shear and settle significantly faster than conventional activated sludge flocs.…”

Section: Introductionmentioning

confidence: 99%

Micro-scale observations of the structure of aerobic microbial granules used for the treatment of nutrient-rich industrial wastewater

2008

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The structure and function of aerobic microbial granules from a lab-scale sequencing batch reactor treating nutrient-rich abattoir wastewater were investigated. These wastewater-fed granules were examined using a wide range of micro-scale techniques including light microscopy, scanning and transmission electron microscopy, fluorescent in situ hybridisation (FISH) combined with confocal laser scanning microscopy and oxygen and pH microsensors, in conjunction with a range of measurements in the bulk liquid phase. Interesting structural features were observed in these granules that have not been reported in synthetic-fed granules. The complex nature of abattoir wastewater was suggested to be responsible for accelerating the breaking process of large mature granules due to a rapid clogging of the granules pores and channels and for the very diverse microbial community observed displaying specific spatial distribution throughout the granules. More importantly, the dissolution at lower pH of mineral complexes associated to the granule matrix of extracellular polymeric substances might have caused the structural damages observed on the granules even though some pH buffer capacity was observed inside these granules. Ciliate protozoa were found to be very abundant on the surface of these wastewater-fed granules, which could potentially assist with reducing the high levels of suspended solids usually present in the aerobic granular sludge effluent. All these observations provide support to future studies on aerobic granular sludge treating real wastewater especially with regard to the granule structure and the mechanisms involved in their formation.

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A novel granular sludge sequencing batch reactor for removal of organic and nitrogen from wastewater

Cited by 129 publications

References 15 publications

Microbial extracellular polymeric substances: central elements in heavy metal bioremediation

Microbial extracellular polymeric substances: central elements in heavy metal bioremediation

Microbial community and N removal of aerobic granular sludge at high COD and N loading rates

Micro-scale observations of the structure of aerobic microbial granules used for the treatment of nutrient-rich industrial wastewater

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