Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability

Jason Dwyer, Starrenberg, Daniel, Stephan Tait, Barr, Keith, Batstone, Damien J. and Lant, Paul A. (2008) Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability. Water Research, 42 18: 4699-4709. doi:10.1016/j.watres.2008.08.019


Author Jason Dwyer
Starrenberg, Daniel
Stephan Tait
Barr, Keith
Batstone, Damien J.
Lant, Paul A.
Title Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability
Journal name Water Research   Check publisher's open access policy
ISSN 0043-1354
Publication date 2008-01-01
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.watres.2008.08.019
Open Access Status
Volume 42
Issue 18
Start page 4699
End page 4709
Total pages 11
Place of publication Amsterdam Netherlands
Publisher Academic Press (Elsevier Press)
Language eng
Subject C1
9699 Other Environment
090409 Wastewater Treatment Processes
Abstract Activated sludges are becoming more difficult to degrade in anaerobic digesters, due to the implementation of stricter nitrogen limits, longer sludge ages, and removal of primary sedimentation units. Thermal hydrolysis is a popular method to enhance degradability of long-age activated sludge, and involves pressure and heat treatment of the process fluid (150-160 °C saturated steam). However, as documented in this study, in a full-scale system, the use of thermal hydrolysis produces coloured, recalcitrant compounds that can have downstream impacts (e.g., failure of UV disinfection, and increased effluent nitrogen). The coloured compound formed during thermal hydrolysis was found to be melanoidins. These are coloured recalcitrant compounds produced by polymerisation of low molecular weight intermediates, such as carbohydrates and amino compounds at elevated temperature (Maillard reaction). By decreasing the THP operating temperature from 165 °C to 140 °C, THP effluent colour decreased from 12,677 mg-PtCo L to 3837 mg-PtCo L. The change in THP operating temperature from 165 °C to 140 °C was shown to have no significant impact on anaerobic biodegradability of the sludge. The rate and extent of COD biodegradation remained largely unaffected by the temperature change with an average first order hydrolysis rate of 0.19 d and conversion extent of 0.43 g-COD g-COD.
Keyword Anaerobic; Melanoidin; UVT; DON; Biological methane potential; Ultrafiltration fractionation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
Advanced Water Management Centre Publications
 
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Created: Thu, 26 Mar 2009, 00:59:17 EST by Suzanne Read on behalf of Advanced Water Management Centre