Biophysicochemical study of biodigesters fed with pig and bovine manure, in Sumapaz Province, Colombia

Abstract

In recent years, the construction of biodigestion systems has been implemented, achieving effective results in economic, energy and environmental matters, where the annual production of biogas has increased to significant levels with the purpose of producing electrical and heat energy (Steyer et al. 2006). The work aimed to evaluate the behavior of 4 biodigesters supplied with bovine and porcine excreta and to assess the biophysicochemical quality of their biols, in Fusagasuga Municipality, Cundinamarca. Five moments of analysis of variables in the field (T, HR, pH) and sampling of tributaries, effluents from four biodigesters, located in production systems (3 pigs and 1 bovine) in Fusagasugá Municipality were performed. Samples were transported to the nutrition laboratory of University of Cundinamarca, where through instrumental analytical techniques such as potentiometric tests, gravimetry, multiparametric measurement, titration and spectrophotometry, variables like pH, total dissolved solids (TDS), electrical conductivity (EC), nitrogen, phosphorus and potassium were evaluated. Biophysicochemical indicators determined in liquid fertilizers-biols, showed slightly alkaline pH values, high EC and TDS, moderately concentrated available nitrogen and potassium contents and slightly lower phosphorus values than those reported in other similar works, which allows recommending them for use as liquid biofertilizers in moderately tolerant crops. Biogas produced in Mirador and Santa Bárbara biodigesters presented the highest concentration of methane gas, significantly exceeding (P<0.050) the CH4 obtained in Meseta and Saucita, which can be explained by the type of substrate used (pig and bovine manure) and the weather conditions of the farms studied.