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Die-off of enteric bacterial pathogens during mesophilic anaerobic digestion

Horan, NJ, Fletcher, L, Betmal, SM, Wilks, SA and Keevil, CW (2004) Die-off of enteric bacterial pathogens during mesophilic anaerobic digestion. Water Research, 38 (5). 1113 - 1120 . ISSN 0043-1354


Conventionally treated sewage sludge may contain high concentrations of potentially pathogenic microorganisms and additional treatment is required to minimise the risks to health if it is to be recycled to agricultural land. Mesophilic anaerobic digestion (MAD) is the most widely used process in the UK for stabilising sludge prior to agricultural recycling, but little is known about the fate of a number of enteric pathogens as the sludge passes through the treatment processes. The aim of this study was to determine the efficiency of MAD in removing the bacterial enteric pathogens, Salmonella senftenberg, Listeria monocytogenes and Campylobacter jejuni which were added as a spike to the digester feedstock, together with the die-off of indigenous Escherichia coli already present in the sludge. The primary sludge digestion stage of MAD was found to achieve a log removal of 1.66 for E. coli, 2.23 for L. monocytogenes and 2.23 for S. senftenberg. However, the extent of die-off was a function of the numbers of pathogens in the feed and as these increased the log removal also increased. The numbers of C. jejuni were not affected by primary sludge digestion. Additional die-off was provided by secondary sludge digestion with log removals of 1.70 for E. coli, 2.10 for S. senftenberg and 0.36 for C. jejuni.

Item Type: Article
Keywords: Agriculture, Bacteria, Anaerobic, Bioreactors, Campylobacter, Conservation of Natural Resources, Escherichia coli, Listeria, Population Dynamics, Refuse Disposal, Salmonella, Sewage, Water Purification
Institution: The University of Leeds
Academic Units: The University of Leeds > Faculty of Engineering (Leeds) > School of Civil Engineering (Leeds) > Inst for Pathogen Control Engineering (Leeds)
The University of Leeds > Faculty of Engineering (Leeds) > School of Civil Engineering (Leeds)
Depositing User: Symplectic Publications
Date Deposited: 11 Feb 2011 11:52
Last Modified: 15 Sep 2014 04:01
Status: Published
Publisher: Elsevier Science Ltd
Identification Number: 10.1016/j.watres.2003.12.004
URI: http://eprints.whiterose.ac.uk/id/eprint/42791

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