Potencial Bioquímico de Metano da casca de tucumã codigerida com excretas de aves poedeiras

Abstract

The production of biogas through residues associated with agriculture and livestock is evident as one of the alternatives to diversify the Brazilian energy matrix, since agroindustrial residues are characterized by having great potential for the production of clean and cheap energy. In this context, the present work evaluated, on a laboratory scale, the generation of biogas through anaerobic digestion, using excreta from laying birds as inoculum (INO) and tucuma bark as substrate (SUB), these two residues being very present in the production of the State from the Amazon. The proportions used for the experiment were: (i) 75% SUB with 25% INO, (ii) 50% SUB with 50% INO and (iii) 25% SUB with 75% INO, using 08 reactors. The experiment was conducted in duplicates with a Hydraulic Retention Time (HRT) of 37 days and constant temperature maintenance through external water circulation at 37 ± 2ºC. The method established by Justesen, et al. (2019) for measuring the Biochemical Potential of Methane (BPM), which is based on measuring the Gas Density (GD) to estimate the amount of CH4 in biogas. The physicalchemical analyzes showed that the excreta of laying hens has 22.68 ± 0.83% TS, 95.40 ± 2.10% VS, 77.31 ± 0.64% M, and also 30.16 ± 0.15% C, 4.09 ± 0.15% H, 5.46 ± 0.43% N and 34.9 ± 1.20% crude protein. As for the tucuma bark, it has 48.24 ± 0.01% TS, 96 ± 3.30% VS and 51.76 ± 0.93% M and also, 53.74 ± 0.62% C, 7.50 ± 0.17% H, 1.5 ± 0.04% N and 22 ± 0.38% crude protein. Through the method used, it was possible to estimate the biogas produced, observing that the two samples with the highest substrate concentration being in the proportion of 75% SUB and 25% INO were the ones that produced the most biogas, with 620ml and 296ml respectively. And the ones that produced the least were the samples with the lowest concentration of substrate with a proportion of 25% SUB and 75% INO, being 55ml, 56ml and 70ml respectively. However, an accumulated production in duplicate with significant differences was identified and, therefore, identified failures and possible recommendations were listed from sample preparation to the experiment, in order to corroborate future work using the methodology of Justesen, et al. (2019) for measuring BPM through GD.