ISBN: 1-84507 2612
Published Date: 30/04/2002
This study has evaluated the survival of a number of enteric pathogens added to thickened sewage sludge which was subjected to treatment by a range of processes operated under Code of Practice* conditions. These processes were: mesophilic anaerobic digestion (MAD), pasteurisation followed by MAD, lime stabilisation and composting. The experiments were carried out at bench-scale with additions of Salmonella senftenberg, S. dublin, S. enteriditis, S. typhimurium, Listeria monocytogenes, Campylobacter jejuni, Cryptosporidium parvum and poliovirus with the aim of achieving 106 organisms in the sludge. In addition the numbers of indigenous Escherichia coli were determined, not only in the bench-scale reactors but also at nominated full-scale plants that were operated under Code of Practice conditions; thermal drying was evaluated at full-scale only. Indigenous E. coli were shown to have similar survival properties to the verotoxigenic strain of E. coli O157 and could act as an indicator for this pathogen.