Model assisted startup of anaerobic digesters fed with thermally hydrolysed activated sludge

Batstone, D. J., Balthes, C. and Barr, K. (2010) Model assisted startup of anaerobic digesters fed with thermally hydrolysed activated sludge. Water Science and Technology, 62 7: 1661-1666. doi:10.2166/wst.2010.487

Author Batstone, D. J.
Balthes, C.
Barr, K.
Title Model assisted startup of anaerobic digesters fed with thermally hydrolysed activated sludge
Journal name Water Science and Technology   Check publisher's open access policy
ISSN 0273-1223
Publication date 2010
Sub-type Article (original research)
DOI 10.2166/wst.2010.487
Volume 62
Issue 7
Start page 1661
End page 1666
Total pages 6
Editor Helmut Kroiss
Place of publication London, U.K
Publisher IWA Publishing/Portland Press
Collection year 2011
Language eng
Formatted abstract
This paper presents the use of the IWA ADM1 to predict and interpret results from two full-scale anaerobic digesters fed with thermal hyrolysate (waste activated sludge with a long upstream sludge age) from a Cambi hydrolysis process operating at 165°C and 6 bar-g. The first digester was fed conventionally—though intermittently, while the second was heavily diluted through a substantial component of the evaluation period (110 days). There were a number of important outcomes—related to both model application, and model predictions. Input and inert COD: mass ratio was very important, and was considerably higher than the 1.42 g g-1 used for biomass throughout the IWA activated sludge and anaerobic digestion models. Input COD: VS ratio was 1.6 g g-1, and inert COD: VS ratio was 1.7 g g-1. The model succeeded on a number of levels, including effective prediction of important outputs (degradability, gas flow and composition, and final solids), clarification of the substantial data scatter, prediction of recovery times during operationally poor periods, and cross-validation of the results between digester 1 and digester 2. Key failures in model performance were related to an early incorrect assumption of the COD: VS ratio of 1.42 g g-1, and intermittent high acetate levels, most likely caused by inhibition, and rapid acclimatisation to ammonia. The acute free ammonia limit was found to be 0.008 M NH3–N, while the chronic inhibition constant (KI,NH3,ac) was 0.007±0.001 M NH3–N. Overall, this is a complex system, and application of the model added significant confidence to the initial operational decisions during an aggressive startup on an atypical feed.
© IWA Publishing 2010
Keyword Activated sludge
Ammonia inhibition
Thermal hydrolysis
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
Advanced Water Management Centre Publications
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Citation counts: TR Web of Science Citation Count  Cited 8 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 7 times in Scopus Article | Citations
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Created: Sun, 07 Nov 2010, 00:00:22 EST