Evaluation of pressurised carbon dioxide pre-treatment aimed at improving the sanitisation and anaerobic digestibility of co-settled sewage sludge

Abstract

This work reports on the use of pressurized CO₂ pretreatment to improve methane yield and pathogen indicator organism die-off in co-settled sewage sludge (SS). Four semi-continuous mesophilic anaerobic digesters were fed on co-settled SS to establish a baseline for performance and stability. One pair of digesters was then fed with co-settled SS pretreated by P CO₂ at 2800 kPa for 23 h. The trial continued for 70 days during which specific biogas and methane production, volatile solids destruction and loss of viability of Escherichia coli was monitored in test and control digesters. The pretreatment had no positive influence on any of these parameters, which was further confirmed using batch biochemical methane potential tests and direct measurement of die-off of E. coli and Salmonella enterica in samples of different sizes treated in pressure vessels of different sizes and in matrices of nutrient medium and co-settled SS. Pressurised CO₂ pretreatment was effective at killing fecal indicator bacteria in nutrient medium but ineffectual in SS, strongly suggesting that the nature of suspending matrix was a principle determining factor. Paper concludes that pressurized CO₂ pretreatment is not a satisfactory approach to improve either biogas production or pathogen destruction in anaerobic digestion.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata

Altmetrics