Biomethane potential from herbivorous animal's manures: Cuban case study

Anaerobic digestion technology is a feasible alternative for wastes environmental treatment, nutrients recovery (as biofertilizer) and biomethane production. In Cuba, several wastes energy potentials have been evaluated, however, other biomass like horse manure (HM), rabbit manure (RM), and goat manure (GM) has been little studied. This study aims to determine the biochemical methane potential contained in herbivorous animal manures (horse, rabbit and goat) for energy purposes in Cuban context. Anaerobic digestion batch assay in 0.5 L reactors, using a mixture of pig and cow manure anaerobic sludge as inoculum, was performed under mesophilic conditions (35 +/- 2 degrees C) during 40 days. The methane yield potentials of 245, 326 and 112 L CH4 kg/VS were obtained for horse, rabbit and goat manures, respectively, influenced by the difference in their digestive system to digest the grass feedstock. The highest rabbit manure methane potential results attractive for domestic digesters, in which experience is very limited. In addition, due to the availability of horse manure in many municipalities of Cuba, the generation of electricity from this manure (128 GWh/year) could replace 1.4% of the electricity consumed by households, making it promising to further exploitation considering the expected 2030 energetic matrix changes using renewable energy.

Automated summary

Anaerobic digestion technology is a feasible alternative for waste treatment and biomethane production in Cuba. The study showed that horse, rabbit, and goat manures have high methane potential, with rabbit manure being particularly attractive for domestic digesters. Furthermore, the use of horse manure for electricity generation could potentially replace a percentage of household electricity consumption, showing promise for future exploitation in the energy sector.