Estudo dos efeitos da temperatura e diluição dos dejetos suínos na geração de biogás

Abstract

Biogas generation emerges as an environmentally appropriate technological alternative for the disposal and energetic use of manure from animal husbandry. Since the contamination of the environment is increasing, due to the human-induced anthropization and its activities that generate impact, being the contamination of rivers and sheets that supply both rural and urban environments with animal waste, one of the main impacts generated in rural areas. In addition, there is the possibility of reducing expenses associated with the purchase of liquefied petroleum gas (LPG), fertilizers, as well as the option of using the heat released in the biogas burning in industrial processes or in the generation of electricity. However, the scope of this work is the generation of biogas and its effects due to the temperature and the dilution of the biomass (pig slurry) produced by the anaerobic digestion process, which favors anaerobic microorganisms capable of consuming organic matter present in the swine waste and in its metabolic process produce methane (CH4), carbon dioxide (CO2) and other gases in a generally irrelevant concentration, with CH4 being the energetic gas of interest. Although there are many factors that influence the production of CH4, this research seeks to focus on the thermal effects of biomass and its dilution, as low temperatures, as observed mainly in southern Brazil in certain seasons of the year, occurs to the thermal inactivation of bacteria, drastically reducing gas production. In addition, the presence of water is essential in the metabolic process of bacteria to produce CH4. Therefore, different dilutions (Gross, 1:0.5, 1:1, 1:1.5 and 1:2) and temperatures (86 °F, 95 °F and 104 °F) were evaluated to finally determine which the appropriate conditions to provide greater biogas production. In this study, the yield of CH4 was the lowest at the temperature of 86 °F and the different dilutions did not show great variation of production. On the other hand, at temperatures of 95 °F and 104 °F, with the temperature being 95 °F at which it presented the highest production, the dilution proved to be important for a high yield. The analyzes performed were of COD, TS, FS, VS and pH, besides a specific method presented during the work to measure CH4.