title: Optimization of the anaerobic co-digestion of pasteurized slaughterhouse waste, pig slurry and glycerine.
abstract: The feasibility of co-digestion of blends of two different animal by-products (pig manure and pasteurized slaughterhouse waste) and recovered glycerine was studied in mesophilic conditions. Experiments were performed in a lab-scale CSTR along 490days, with a hydraulic retention time of 21-33days and with a step-wise increased organic loading rate, by adding and/or changing the wastes ratio, from 0.8 to 3.2kgCODm-3d-1. The best methane production rate (0.64Nm3CH4m-3d-1) represented an increment of 2.9-fold the initial one (0.22Nm3CH4m-3d-1with pig manure solely). It was attained with a ternary mixture composed, in terms of inlet volatile solids, by 35% pig slurry, 47% pasteurized slaughterhouse waste and 18% glycerine. This blend was obtained through a stepwise C/N adjustment: this strategy led to a more balanced biodegradation due to unstressed bacterial populations through the performance, showed by the VFA-related indicators. Besides this, an improved methane yield (+153%) and an organic matter removal efficiency (+83%), regarding the digestion of solely pig slurry, were attained when the C/N ratio was adjusted to 10.3.
authors.affiliation: IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, E-08140, Caldes de Montbui, Barcelona, Spain; EnergyLab, Edificio CITEXVI - Local 1, Fonte das Abelleiras, s/n, Campus Universitario de Vigo, E-36310 Vigo, Spain.
authors.forename: Ángela
authors.initials: Á
authors.lastname: Rodríguez-Abalde
authors.affiliation: GIRO Joint Research Unit IRTA-UPC, Department of Agrifood Engineering and Biotechnology, Universitat Politècnica de Catalunya - BarcelonaTECH, Parc Mediterrani de la Tecnologia, Building D-4, E-08860, Castelldefels, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Flotats
authors.affiliation: IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, E-08140, Caldes de Montbui, Barcelona, Spain. Electronic address: belen.fernandez@irta.cat.
authors.forename: Belén
authors.initials: B
authors.lastname: Fernández
mesh_terms: D000003:Abattoirs; D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005990:Glycerol; D008372:Manure; D008697:Methane / Q000096:biosynthesis; D009584:Nitrogen / Q000378:metabolism; D061352:Pasteurization; D034421:Sus scrofa; D018505:Waste Management / Q000295:instrumentation / Q000379:methods*
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D008372:Manure; D002244:Carbon; D009584:Nitrogen; D008697:Methane; D005990:Glycerol
keywords: C/N ratio; Co-digestion; Glycerin; Pig slurry; Slaughterhouse waste