title: Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.
abstract: The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency.
authors.affiliation: a Department of Food Biotechnology , Instituto de la Grasa (CSIC) , Sevilla , Spain.|b Chemical Engineering Department , Universidad de La Frontera , Temuco , Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Beltrán
authors.affiliation: b Chemical Engineering Department , Universidad de La Frontera , Temuco , Chile.
authors.forename: David
authors.initials: D
authors.lastname: Jeison
authors.affiliation: a Department of Food Biotechnology , Instituto de la Grasa (CSIC) , Sevilla , Spain.
authors.forename: Fernando G
authors.initials: FG
authors.lastname: Fermoso
authors.affiliation: a Department of Food Biotechnology , Instituto de la Grasa (CSIC) , Sevilla , Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Borja
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D002708:Chlorella / Q000378:metabolism*; D017744:Medical Waste Disposal / Q000379:methods*; D008697:Methane / Q000378:metabolism*; D058086:Microalgae / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013030:Spain; D013696:Temperature
chemical_list: D017744:Medical Waste Disposal; D012722:Sewage; D008697:Methane
keywords: Anaerobic co-digestion; batch studies; mesophilic temperature; microalgae; waste activated sludge