Digestão anaeróbia de bagaço de cana- de-açúcar: estratégia de armazenamento e pré-tratamento para aumentar a produção de biogás

Abstract

Sugarcane bagasse (SCB) stands out as lignocellulosic biomass from the production of ethanol. This residue presents potential of energy generation, through anaerobic digestion (AD), however the lignocellulosic residues present a complex structure, composed of cellulose, hemicellulose and lignin, being necessary pre-treatments to improve the digestibility of these residues and consequently the process of AD. However, these pre-treatments are expensive to implement and generate by products toxic to the environment. As an alternative, co-storage between lignocellulosic substrates and organic waste can provide increased biogas production, reducing reagent costs and mitigating environmental impacts. The objective of this work was to evaluate the effect of co-storage of SCB with organic residues using three concentrations of SCB for fruit and vegetable residues (FVW) (5%, 10% and 15%) and for whey (CW) (10%, 20% and 25%) in biogas production. The biogas production synergy of the blend was compared with the theoretical biogas production (PBMt) and with the conventional pretreatment effect with NaOH (1%, 5% and 10%). Methane production from the co-storage of FVW + SCB5% presented the best conversion rate in methane, with 27% efficiency when compared to PBMt, whereas none of the concentrations of CW presented efficiency. Conventional alkaline pretreatment with NaOH showed efficiency when compared to in natura SCB to 5% and 10%. The study showed that the low concentration of lignocellulosic residues provides the increase of the contact surface with the acidic co-substrate, favoring the pretreatment through the acid generated in the degradation.