Excrement biodigester design for biogas generation via simulation with SIMBA® software

Abstract

A biodigester generates biogas and stabilized digestate that is sanitized depending on the temperature. “Mi Granjita Huevos El Dorado” is an egg - producing farm located in the rural area of Neiva, with 1,325 laying hens whose excrement is not properly disposed of, contaminating: the soil due to its use as fertilizer without eliminating pathogenic microorganisms, reducing the capacity of drainage and hindering oxygen mineralization; the water with nitrate leachate, and the air with ammonia and bad odors and subsequent spread of insects, affecting the health of the population and generating costs in collection/treatment. The research evaluated the biogas generation potential of a biodigester using farm manure as a source of organic matter, substrate, or influent, as a first step the mixture of biomass and water was characterized, for this the excrement produced during Six months for the hens and a fattening pig, which would function as an accelerating substrate of anaerobic digestion, 33.46 kg/day were obtained, then the pH of different proportions between chicken manure, pig manure, and water was measured to define the percentage
of mixture with the which would be supplied to the biodigester, with results of 7.31, 6.86 and 7.06, being that of 40% combined biomass and 60% water, the most suitable for being the most neutral. The biodigester was dimensioned reaching the budget for its manufacture and installation, and it was simulated using the SIMBA® software, finding an expected production of 10 m3 / month of biogas, based on the organic load, a temperature of 35 ° C, appropriate for the growth and development of bacteria, and a retention time of 30 days, concluding that biogas production can supply 50% of the natural gas used on the farm, generating a return on investment in a period of three years.