Produção de metano a partir da codigestão anaeróbia de vinhaça e melaço

Abstract

This study aimed to determine the methane production from the co-digestion of vinasse and molasses, using batch biodigester and UASB reactor sludge from a domestic sewage treatment plant as inoculum. Three factors were varied: the proportion of vinasse/molasses substrates (25/75, 50/50 and 75/25 – v/v), the COD (3000, 6000 and 9000 mg/L) and the addition of alkalizing agent (0.50, 1.00 and 1.50 g/gCOD). Reactors with 310 mL of total volume and 150 mL of reaction volume were used. The reactors were kept at mesophilic temperature (35 °C) and under constant stirring at 120 rpm. Methane production yields ranged from 33.75 to 297.85 mLCH4/gSV and COD removal ranged from 2.92 to 58.41%. The highest methane productions occurred in the reactors that had less alkalizing agent, which may indicate that the increase in the concentration of sodium bicarbonate could cause an inhibition in the production of methane. In addition, the statistical analyzes indicated that the alkalizing was the parameter that most interfered in the performance of the process. Thus, co-digestion with vinasse and molasses was favorable to produce metane, indicating the potential of this process to use the byproducts of the sugar and ethanol industry and its valorization as an energy resource.