Influence of shaving woods bed material for dairy cattle on biogas methane content

The biogas processes are well resolved commercially in Brazil. However, the heterogeneity of the agroindustrial effluents, influenced by the different handlings adopted, demand better understanding, especially of dairy cattle, where normally it employs the use of shaving woods like bed for dairy cows. The shaving woods can negatively influence the process of anaerobic digestion, because it is a tough material for degradation, besides absorbing part of the volatile solids, which are essential to the process of biogas generation. Consequently the shaving woods can lower the calorific value of biogas, reducing the concentration of methane in the biogas. The objective of this study was to evaluate the influence of shaving woods used like bed for bovines, on the methane content in biogas. The experimental delimitation was randomized in blocks with four treatments, performed in triplicate, such as: (T1) raw effluent; (T2) liquid extruded effluent; (T3) pasty extruded effluent; and the (T4) white control or inoculum, totaling 24 sampling units. The laboratory analyses were done in the International Renewable Energy Center (CIbiogas), in the city Foz do Iguacu, PR. Besides being considered one of the best laboratories in Latin America is the only biogas laboratory in Brazil that provides service. Assays of biogas production were performed in eudiometer batch of 250 mL. Multivariate analysis was adopted by means of multiple linear regression model to delineate a regression model and with significant accuracy (p <0.01) it was found variation in the methane content of 65.30 – 53.65%. Therefore, the shaving woods may significantly affect the anaerobic digestion of effluent.