title: Investigation of the optimal percentage of green seaweed that may be co-digested with dairy slurry to produce gaseous biofuel.
abstract: Ulva lactuca, a green seaweed, accumulates on beaches and shallow estuaries subject to eutrophication. As a residue, and a macro-algae, it is a source of sustainable third generation biofuel. Production of biomethane from mono-digestion of U. lactuca, however is problematic due to high levels of sulphur and low ratios of carbon to nitrogen. Fresh and dried U. lactuca were continuously co-digested with dairy slurry at ratios of 25%, 50% and 75% (by volatile solid content) in 6 number 5L reactors for 9months. The reactors digesting a mix with 75% U. lactuca struggled to reach stable conditions. Volatile fatty acid levels of 14,000mgl(-1) were experienced. The levels of ammonia increased with percentage U. lactuca in the mix. Optimum conditions were observed with a mix of 25% fresh U. lactuca and 75% slurry. A yield of 170LCH4kg(-1)VS was achieved at an organic loading rate of 2.5kgVSm(-3)d(-1).
authors.affiliation: Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland.
authors.forename: Eoin
authors.initials: E
authors.lastname: Allen
authors.affiliation: Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland.
authors.forename: David M
authors.initials: DM
authors.lastname: Wall
authors.affiliation: Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland. Electronic address: jerry.murphy@ucc.ie.
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D019149:Bioreactors; D002417:Cattle; D005232:Fatty Acids, Volatile / Q000378:metabolism; D007494:Ireland; D008372:Manure / Q000032:analysis* / Q000382:microbiology; D008697:Methane / Q000096:biosynthesis*; D013057:Spectrum Analysis; D044445:Ulva / Q000737:chemistry* / Q000378:metabolism
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D008372:Manure; D000641:Ammonia; D008697:Methane
keywords: Biofuel; Biomethane; Seaweed; Ulva lactuca