title: Performance evaluation of micro-aerobic hydrolysis of mixed sludge: Optimum aeration and effect on its biochemical methane potential.
abstract: This study evaluated the performance of a micro-aerobic hydrolysis of mixed sludge and its influence as a pretreatment of this waste for its subsequent anaerobic digestion. Three experimental series were carried out to evaluate the optimum micro-aeration levels in the range from 0.1 to 0.5 air volume/min.reactor volume (vvm) and operation times within the range of 24-60 h. The maximum methane yield [35 mL CH4/g volatile suspended solids (VSS) added] was obtained for an aeration level of 0.35 vvm. This methane yield value increased 114% with respect to that obtained with the non-aerated sludge. In the micro-aeration process carried out at an aeration level of 0.35 vvm, increases in soluble proteins and total sugars concentrations of 185% and 192% with respect to their initial values were found, respectively, after 48 h of aeration. At the above micro-aerobic conditions, soluble chemical oxygen demand (CODS) augmented 150%, whereas VSS content decreased until 40% of their initial respective values. Higher COD increases and VSS decreases were found at 60 h of micro-aeration, but the above parameters did not vary significantly with respect to the values found at 48 h.
authors.affiliation: a Department of Chemical Engineering , Universidad de Santiago de Chile , Santiago de Chile , Chile.
authors.forename: Silvio
authors.initials: S
authors.lastname: Montalvo
authors.affiliation: a Department of Chemical Engineering , Universidad de Santiago de Chile , Santiago de Chile , Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Ojeda
authors.affiliation: a Department of Chemical Engineering , Universidad de Santiago de Chile , Santiago de Chile , Chile.
authors.forename: César
authors.initials: C
authors.lastname: Huiliñir
authors.affiliation: b Department of Chemical and Environmental Engineering , Universidad Federico Santa María , Valparaíso , Chile.
authors.forename: Lorna
authors.initials: L
authors.lastname: Guerrero
authors.affiliation: c Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide , Sevilla , Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Borja
authors.affiliation: a Department of Chemical Engineering , Universidad de Santiago de Chile , Santiago de Chile , Chile.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Castillo
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D006868:Hydrolysis; D008697:Methane / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D008697:Methane
keywords: Aerobic hydrolysis; anaerobic digestion; methane production; micro-aeration; mixed sludge