Codigestión de residuos sólidos urbanos con gallinaza y boñiga para la producción de energía renovable en Costa Rica

Abstract

Costa Rica generates approximately 1.6 million tons of municipal solid waste annually, with a significant proportion corresponding to the organic fraction (FORSU). This study evaluated the anaerobic codigestion of FORSU with poultry manure and cattle manure to enhance biogas production and energy recovery. Biochemical methane potential (BMP) tests were conducted at laboratory scale, using cosubstrate-to-FORSU mass ratios in terms of volatile solids of 25:75, 50:50, and 75:25. Results showed that codigestion with poultry manure improved methane yields by up to 30% compared to FORSU alone, reaching 405 L CH4/kg VS for the best-performing mixture (25:75 poultry manure:FORSU), while codigestion with cattle manure achieved a more modest 3% increase. Based on experimental data, theoretical national scenarios were developed. Full valorization of FORSU via codigestion with poultry manure could generate approximately 402 GWh/year of electricity, enough to supply around 318,500 households. This would represent 3.43% of Costa Rica's total electricity generation. Despite its limited contribution to the energy matrix, anaerobic codigestion of FORSU offers significant advantages for sustainable waste management and supports the transition toward a circular economy model.