title: Investigation of effect of particle size and rumen fluid addition on specific methane yields of high lignocellulose grass silage.
abstract: This work examines the digestion of advanced growth stage grass silage. Two variables were investigated: particle size (greater than 3 cm and less than 1cm) and rumen fluid addition. Batch studies indicated particle size and rumen fluid addition had little effect on specific methane yields (SMYs). In continuous digestion of 3 cm silage the SMY was 342 and 343 L CH4 kg(-1)VS, respectively, with and without rumen fluid addition. However, digester operation was significantly affected through silage floating on the liquor surface and its entanglement in the mixing system. Digestion of 1cm silage with no rumen fluid addition struggled; volatile fatty acid concentrations rose and SMYs dropped. The best case was 1cm silage with rumen fluid addition, offering higher SMYs of 371 L CH4 kg(-1)VS and stable operation throughout. Thus, physical and biological treatments benefited continuous digestion of high fibre grass silage.
authors.affiliation: Environmental Research Institute, School of Engineering, University College Cork, Cork, Ireland; Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
authors.forename: D M
authors.initials: DM
authors.lastname: Wall
authors.affiliation: Environmental Research Institute, School of Engineering, University College Cork, Cork, Ireland; Department of Agricultural, Food and Environmental Science, Perugia University, Perugia, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Straccialini
authors.affiliation: Environmental Research Institute, School of Engineering, University College Cork, Cork, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: Allen
authors.affiliation: Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Nolan
authors.affiliation: Environmental Research Institute, School of Engineering, University College Cork, Cork, Ireland; Science Foundation Ireland (SFI), Marine Renewable Energy (MaREI) Centre, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
authors.forename: P
authors.initials: P
authors.lastname: O'Kiely
authors.affiliation: Environmental Research Institute, School of Engineering, University College Cork, Cork, Ireland; Science Foundation Ireland (SFI), Marine Renewable Energy (MaREI) Centre, Ireland. Electronic address: jerry.murphy@ucc.ie.
authors.forename: J D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D000818:Animals; D005232:Fatty Acids, Volatile / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D010316:Particle Size; D006109:Poaceae / Q000737:chemistry*; D012417:Rumen / Q000737:chemistry*; D012820:Silage
chemical_list: D005232:Fatty Acids, Volatile; C036909:lignocellulose; D008031:Lignin; D008697:Methane
keywords: Anaerobic digestion; Biomethane; Grass silage; Particle size; Rumen fluid