title: Effect of freezing on the conservation of the biological activity of organic solid wastes.
abstract: To assess the effect of freezing on the indigenous biological activity of an organic waste, five types of organic wastes (raw sludge [RS], municipal solid waste [MSW], partially processed municipal solid waste [MSWpp], digested sludge [DS] and composted organic fraction of municipal solid waste [OFMSWc]) were frozen and stored during different times to identify if the interruption of the native biological activity was recovered. Respiration indices (DRI(24h) and AT(4)) were used to determine the biological activity expressed as oxygen consumption. ANOVA analysis was used to compare the results. Respiration indices of RS, DS, MSWpp and OFMSWc were not affected by freezing storage during 1 year. Contrarily, respiration indices of MSW samples were statistically different after 52 and 20 weeks of freezing storage (DRI(24h) and AT(4), respectively). Regarding the lag phase and the time to reach maximum respiration activity, frozen samples induced a significant change in the organic samples analyzed except for OFMSWc.
authors.affiliation: Composting Research Group, Department of Chemical Engineering, Universitat Autònoma de Barcelona, Bellaterra, Cerdanyola del Vallès, 08193 Barcelona, Spain.
authors.forename: Michele
authors.initials: M
authors.lastname: Pognani
authors.forename: Raquel
authors.initials: R
authors.lastname: Barrena
authors.forename: Xavier
authors.initials: X
authors.lastname: Font
authors.forename: Antoni
authors.initials: A
authors.lastname: Sánchez
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D005615:Freezing; D009930:Organic Chemicals / Q000302:isolation & purification / Q000378:metabolism*; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000382:microbiology*
chemical_list: D009930:Organic Chemicals; D012722:Sewage