Co-digestão anaeróbia dos dejetos de suínos e forragens em idades diferentes de maturação

Abstract

The growing demand for electricity is causing an intense search for renewable energy sources, seeking to meet all the demand, as well as producing in a more sustainable way. There are currently several studies on the biogas production potential of forage species and agricultural residues together with animal waste, since these products are raw materials with high methane production potential and consequent generation of electricity. The objective of this academic work was to evaluate if forage inclusions at two different maturation ages, in co- digestion with swine manure, affect biogas production and degradation of solid constituents during the process. For the execution of the experiment, a completely randomized design was used in a factorial scheme consisting of: 2 forage maturation ages (median and advanced) and 5 doses of forage inclusion (0, 25, 50, 75 and 100%) in the substrates, replacing the wastes, containing 3 repetitions per treatment (biodigesters). The forages were collected at two maturity ages, defined by the availability of green mass in the area, and thus named as high and low availability. Waste and forage were individually characterized by determining the hydrogen potential (pH), the total solids (TS), volatile solids (VS), carbon (C) and nitrogen (N) contents. The forages had the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) quantified. The results were submitted to analysis of variance, considering as sources of variation the type of manure, forage maturation and its inclusion, tested at 5% probability. There was no significant difference (p> 0.05) in relation to forage inclusions and age for biogas yields per kg of ST and SV added. In the ST, SV, C, N reductions and for the pH values only the NDF reductions showed significant differences (p <0.05) between the plant ages, where the largest reduction was found for the medium-aged forage. (65.29%), which may be related to several factors that occurred during processing. Thus forage can be used in both maturation states.