A methodology for optimising feed composition for anaerobic co-digestion of agro-industrial wastes

• DOI: 10.1016/j.biortech.2009.09.061
• Publication Date: 2009-10-15T08:29:10Z
• Authors: J.A. Álvarez; L. Otero; J.M. Lema
• Keywords: Biogas

An optimisation protocol for maximising methane production by anaerobic co-digestion of several wastes was carried out. A linear programming method was utilised to set up different blends aimed at maximising the total substrate biodegradation potential (L CH(4)/kg substrate) or the biokinetic potential (L CH(4)/kg substrate d). In order to validate the process, three agro-industrial wastes were considered: pig manure, tuna fish waste and biodiesel waste, and the results obtained were validated by experimental studies in discontinuous assays. The highest biodegradation potential (321 L CH(4)/kg COD) was reached with a mixture composed of 84% pig manure, 5% fish waste and 11% biodiesel waste, while the highest methane production rate (16.4 L CH(4)/kg COD d) was obtained by a mixture containing 88% pig manure, 4% fish waste and 8% biodiesel waste. Linear programming was proved to be a powerful, useful and easy-to-use tool to estimate methane production in co-digestion units where different substrates can be fed.