The role of extracellular exopolymers in the removal of phosphorus from activated sludge

Cloete, T.E.; Oosthuizen, D.J.

doi:10.1016/s0043-1354(01)00093-8

Cited by 109 publications

(47 citation statements)

References 7 publications

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“…However the P binding capacity of EPS has only rarely been described and has not been considered ecologically. Cloete and Oosthuizen (2001) have shown that cell clusters with associated EPS in activated sludge systems contained between 57 and 59% P, while almost 30% was found in EPS alone. These values correspond well with our results, where, except for the red layer, 28-30% P was found in the exchangeable and loosely bound fraction during the day.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal changes in phosphorus partitioning within a freshwater cyanobacterial mat community

et al. 2010

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Spatial and temporal changes in phosphorus (P) distribution, partitioning and mobility in the benthic cyanobacterial mat (CBM) were evaluated using sequential chemical fractionation. Total P (TP) content was extremely low, ranging from 0.025 to 0.1 mg g -1 DW. Exchangeable and loosely bound P, which we consider to be mainly associated with extracellular polymeric substances (EPS), constituted the most significant proportion of TP (up to 52%, 55 lg g -1 DW), followed by P associated with the authigenic apatites (up to 35% of TP or 18 lg g -1 DW). While we found virtually no exchange of P with the ambient environment, our results show that the partitioning of P forms within CBM is dependent on spatial and temporal fluctuations of physico-chemical parameters, mainly pH and dissolved oxygen. A conspicuous diurnal increase in the reactive, exchangeable and loosely bound P in the top CBM layers was observed. This observation has important ecological implications, as CBM microorganisms therefore have an increased possibility for P ''luxury'' uptake during the night. This hypothesis is further supported by the fact that P in the organic fraction rises by as much as 53% in the upper layers during the night, indicating some form of cellular uptake. The P-binding potential of EPS also has ecological or biogeochemical consequences and should be considered in stoichiometrical studies where it represents potential danger for great overestimates of cellular P values or the nutritional status of cells.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal changes in phosphorus partitioning within a freshwater cyanobacterial mat community

et al. 2010

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“…The separated EPS was lyophilized and measured by an environmental scanning electron microscopy (ESEM, FEI Quanta 200F, Netherlands) equipped with an energy-dispersive spectrum (EDS), and samples and two controls were prepared followed by the methods of Cloete and Oosthuizen (2001).…”

Section: Eps Extraction and Phosphorus Speciation Analysismentioning

confidence: 99%

“…Furthermore, it was elucidated that extracellular polymeric substances (EPS) could act as a reservoir of phosphorus in EBPR system, which played a great role in nutrient removal (Cloete and Oosthuizen 2001;Zhang et al 2013). Besides the accumulation of phosphorus in EPS, a large amount of ortho-P was normally removed accompanying with the cell growth (Hirota et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous denitrification and phosphorus removal by Agrobacterium sp. LAD9 under varying oxygen concentration

Chen

Gui

et al. 2015

Appl Microbiol Biotechnol

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Although efficient aerobic denitrification has received increasing attention, few studies have been made on simultaneous denitrification and phosphorus removal (SDPR) under aerobic condition. In this study, SDPR by an efficient aerobic denitrifier, Agrobacterium sp. LAD9, was firstly demonstrated. High nitrate and phosphorus removal rates of 7.50 and 1.02 mg L(-1) h(-1) were achieved in wide range of O2 concentration from 5.92 to 20.02 mg L(-1). The N2O production would be inhibited as O2 concentration exceeded 11.06 mg L(-1), while the phosphorus removal efficiency would be generally improved with increasing O2 concentration. (15)N mass spectrometry revealed that nitrogen removal accorded with the typical aerobic denitrification pathway, while (31)P nuclear magnetic resonance spectroscopy ((31)P NMR) indicated the fate of phosphorus to cells, extracellular polymeric substances (EPS), and polyphosphate (poly-P) of the denitrifier. EPS acted as a reservoir of phosphorus and the transformation of poly-P was dynamic and depended on initial orthophosphate (ortho-P) content. The aerobic SDPR would greatly simplify the conventional wastewater treatment processes which required separated considerations of nitrogen and phosphorus removal.

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“…The activated sludge fl ocs are an agglomeration of bacteria maintained together due to the presence of extracellular exopolymers (EPS). Cloete and Oosthuizen [6] have examined the composition of extracellular exopolymers and found that they contained on average between 27% and 30% phosphorous. Disintegration of activated sludge fl ocs results therefore in mechanical destruction of EPS and bacteria dispersion as well as partial or complete bacteria cells destruction itself.…”

Section: Nutrients In the Process Of Anaerobic Digestionmentioning

confidence: 99%

Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

Suschka¹,

Grűbel²

2014

Archives of Environmental Protection

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Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifi cations of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step -mesophilic and thermophilic -anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH 4 /dm 3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

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The role of extracellular exopolymers in the removal of phosphorus from activated sludge

Cited by 109 publications

References 7 publications

Spatial and temporal changes in phosphorus partitioning within a freshwater cyanobacterial mat community

Spatial and temporal changes in phosphorus partitioning within a freshwater cyanobacterial mat community

Simultaneous denitrification and phosphorus removal by Agrobacterium sp. LAD9 under varying oxygen concentration

Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

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