Producción de bioelectricidad microbiana utilizando residuos orgánicos como sustrato para dos casos de estudio: Andes- Amazonía, Ecuador

Abstract

The present investigation compared the production of microbial bioelectricity using organic residues as substrate, 50:50 ratio of fruits and vegetables, with soils from the Achuar Kaiptach Community-AMAZONIA, and the Pichan Central Community-ANDES. For the Amazonia case study (CAM), experiments were conducted at the Chanquak-Macas Foundation facilities; for the Andes, at the School of Natural Resources-ESPOCH. The research is based on the deductive research method. Soil was sampled in the ANDES: 763143E, 9833826N and in the AMAZONIA: 263787E, 9708162N at a depth between 20-40cm. The physical-chemical analysis of the initial soil was performed according to the OLSEN methodology within the Department of Soils-Faculty of Natural Resources; the microbiological analysis used the method: dilutions, techniques: sowing by pouring on plate and sowing on surface, using media enriched with glucose, starch, milk, distilled water (at the end of the experiment) and PCA (at the beginning and end of the experiment) in each place, size and repetition of MFC, within the laboratory of Environmental Biotechnology - Faculty of Sciences-ESPOCH. The configuration of the MFC reactors of each treatment used polyethylene pans at different sizes (V1=20L, V2=12L; V3=4L) where the Microbial Fuel Cells (MFCs) had experimental volumes: V1=0.06355m3; V2=0.04335m3; V3=0.02356m3and carbon fiber electrodes with surface area: V1 and V2=0.30m*0.25m; V3=0.20m*0.18m, connection lizards and copper wire to fix the external circuit and multimeters. The microbiological analysis used equipment such as: autoclave, laminar flow chamber. The initial physical-chemical analysis showed similarity in parameters such as pH, percentage of organic matter (%O.M.), electrical conductivity (E.C.), NH4 and differences in P, K, CaO, MgO, C/N ratio, %H. In the initial heterotrophic count, the AMAZONIA: 7*107 Colony Forming Units per gram of soil (CFU/g) and ANDES: 12*106 CFU/g indicating higher quantity but lower microbiological diversity. The Tukey test showed in the Andes case study (CAN), that there are no significant differences between replicates of each size, however there are significant differences between sizes, indicating the Medium treatment as the best, with 316.5659mV. The CAM showed significant differences between replicates of each size, but the best treatment was the Small, with 270.0925mV. For the environmental conditions of the Andes and the Amazon, it is suggested to use a Medium and Small CBM, respectively, according to the scale used in this study. It is concluded that it was feasible to produce bioelectricity using organic solid wastes as microbial fuel in MFC systems in both cases of study. It is recommended to carry out new experiments with CBM systems, and to analyze high Andean soils to broaden the microbiological knowledge to enhance their possible applications.