title: Anaerobic co-digestion of microalgae Chlorella sp. and waste activated sludge.
abstract: The study investigated the growth characteristics of environmental algal strain, Chlorella, in the modified Zarrouk medium and its anaerobic co-digestion with waste activated sludge (WAS). Analysis of extracellular polymeric substances (EPS) in algal culture and WAS indicated that Chlorella secreted more EPS into the surrounding liquid than formed floc-associated EPS as in activated sludge. Mesophilic anaerobic digestion of algae alone required extended digestion period to produce methane, with biogas yield at 262 mL/gVSfed after 45 days of digestion. When algae was co-digested with varying amounts of WAS, 59-96% in mass, not only biogas yield of microalgae improved but the gas phase was reached more quickly. The dewaterability of co-digestion products were also better than two controls digesting WAS or algae only. These results suggest that anaerobic co-digestion of algae and sludge improves the digestibility of microalgae and could also bring synergistic effects on the dewaterability of digested products for existing anaerobic digesters.
authors.affiliation: Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Ashish K
authors.initials: AK
authors.lastname: Sahu
authors.forename: Bjørn
authors.initials: B
authors.lastname: Rusten
authors.forename: Chul
authors.initials: C
authors.lastname: Park
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D019149:Bioreactors; D002708:Chlorella / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage
chemical_list: D056804:Biofuels; D012722:Sewage
keywords: Anaerobic co-digestion; Chlorella; Dewaterability; Extracellular polymeric substances (EPS); Waste activated sludge