Biogas production obtained by swine manure with supplementation of glycerol and residual vegetable oil

Abstract

The anaerobic codigestion of leavings, focusing on the biogas production for the utilization of energy is a way to promote the use of a renewable and accessible source of energy. The biogas obtained by the degradation of swine manure, along with biodiesel production leavings (glycerol) and residual vegetable is an option for generating clean energy and vary the energy matrix. In this study the production of biogas obtained by the degradation of swine manure in laboratorial scale was evaluated with glycerol and residual oil, aiming the increase of the biogas volumes produced. The experiments were conducted by using eighteen reactors, where nine of them were conducted by mesophilic method (37°C) and the other three triplicates were conducted by thermophilic conditions (55°C) over thirty-two running days. The reactors, on both conditions of temperature, were divided in three triplicates: control (only swine manure), swine manure supplemented with glycerol (3%) and swine manure supplemented with vegetable oil (3%). In mesophilic conditions, the results showed satisfactory earnings in terms of biogas generation with good amounts of methane. The glycerol and vegetable oil additions increased the amounts of biogas produced when compared to control triplicate, in which the control, glycerol and residual oil samples resulted in the following volumes: 13.485 mL (containing 69,3% CH₄), 26.356 mL (66,9% CH₄) and 35.194 mL (69,0% CH₄), respectively. The reactors submitted to thermophilic conditions presented a decrease in the biogas and methane values, indicating a possible inhibition of microorganisms.