Phosphate release from waste stabilisation pond sludge: significance and fate of polyphosphate

Powell, N., Shilton, A., Pratt, S. and Chisti, Y. (2011) Phosphate release from waste stabilisation pond sludge: significance and fate of polyphosphate. Water Science and Technology, 63 8: 1689-1694. doi:10.2166/wst.2011.336


Author Powell, N.
Shilton, A.
Pratt, S.
Chisti, Y.
Title Phosphate release from waste stabilisation pond sludge: significance and fate of polyphosphate
Journal name Water Science and Technology   Check publisher's open access policy
ISSN 0273-1223
1996-9732
Publication date 2011
Sub-type Article (original research)
DOI 10.2166/wst.2011.336
Volume 63
Issue 8
Start page 1689
End page 1694
Total pages 6
Place of publication London, United Kingdom
Publisher IWA Publishing
Collection year 2012
Language eng
Abstract Net phosphorus removal from waste stabilisation pond (WSP) systems is governed by the rate of phosphorus incorporation into the sludge layer and the rate of phosphorus release from this sludge back to the overlying wastewater. Luxury uptake of phosphorus by microalgae has been shown to occur under WSP conditions in the laboratory; however, the significance of this mechanism and the fate of polyphosphate contained in the settled solids have not previously been investigated. In this work the analysis of sludge samples from three WSP showed that up to 71% of the total phosphorus in the sludge was in the form of polyphosphate. This indicates that polyphosphate accumulation could potentially be an important mechanism for phosphorus sequestration in WSP and challenges the common view that chemical precipitation is the predominant phosphorus removal mechanism in these systems. The release of phosphate from WSP sludge samples was monitored in the laboratory. The samples from two different pond systems had release rates in the order of 4.3 mgP/gTSS.d. However, the third sample which was collected during an algal bloom had a release rate of 12.4 mgP/gTSS.d. Phosphate release from fresh microalgal sludge grown under laboratory conditions was also studied and was shown to have a release rate of 160 mgP/gTSS.d. Analysis of polyphosphate during the experiments on laboratory grown microalgal sludge showed that polyphosphate was indeed degraded resulting in phosphate release. Interestingly, after the initial release phase phosphorus was assimilated by the biomass and some polyphosphate was reformed. It is likely that this is due to bacterial growth in the sludge.
Keyword Phosphorus
Polyphosphate
Sludge
Waste stabilisation pond
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
Advanced Water Management Centre Publications
 
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Created: Thu, 12 Jan 2012, 13:27:25 EST by Mr Steven Pratt on behalf of Advanced Water Management Centre