Estudio de la producción de biogás y biohidrógeno a partir de la codigestión anaerobia y la fermentación oscura del estiércol bovino como inóculo y el mucílago de café a modo de sustrato

Abstract

In this work we study the production of biogas and biohydrogen from the anaerobic codigestion (at room temperature) and dark fermentation (at T = 50 ° C) of the bovine manure as inoculum and the coffee mucilage as a substrate. The tests were carried out with an inoculum / substrate ratio of 9: 1 and the process was evaluated without acclimation and with acclimation at 8 and 27 days (EBA- 8 days and EBA-27 days). Physicochemical parameters such as pH, alkalinity, volatile fatty acids (VFA), total (ST) and volatile (SV) solids, CHONS, chemical oxygen demand (COD), PCR, metabolites and reducing sugars were measured and monitored; the volume of biogas generated by alkaline displacement was measured daily for 5 weeks and, finally, it was characterized by gas chromatography. Under these conditions, the highest production of biogas was presented for the process with acclimation inoculum-substrate of 27 days, with a PBM of 144.814 ml CH4 / g SV for anaerobic codigestion and 175.322 ml CH4 / g SV in the case of dark fermentation. In the same way, the results by gas chromatography indicate that a biogas rich in methane (greater than 50%) was obtained for both anaerobic codigestion and dark fermentation. To obtain H2 it was proposed to make improvements for the dark fermentation process, including a pretreatment to bovine manure and the addition of a buffer to the reactors, obtaining in this way, the inhibition of the methanogenic stage.