Biodigestão anaeróbia dos dejetos da bovinocultura de corte: influência do período, do genótipo e da dieta

Abstract

RESUMO -Objetivou-se com este estudo identificar possíveis alterações na composição e no processo de biodigestão anaeróbia dos dejetos produzidos por bovinos Canchim e Nelore em diferentes períodos do confinamento e alimentados com diferentes proporções de volumoso e concentrado. O experimento foi conduzido em delineamento inteiramente casualizado em esquema fatorial com parcela subdividida no tempo. As parcelas foram compostas por quatro tratamentos: dejetos provenientes de duas dietas (40% de volumoso e 60% de concentrado e 60% de volumoso e 40% de concentrado) e dois genótipos (Canchim e Nelore) e as subparcelas pelos três períodos de colheita dos resíduos (início, meio e final). A eficiência do processo de biodigestão foi avaliada pelas reduções de sólidos totais (ST), sólidos voláteis (SV), número mais provável (NMP) de coliformes totais e termotolerantes, demanda química e bioquímica de oxigênio, além da produção e dos potenciais de produção de biogás e metano. Não houve efeito do genótipo nem do período sobre a composição dos dejetos, no entanto o aumento da proporção de volumoso na dieta levou a menor eficiência do processo, pois foi observado aumento de 26,31% no volume de metano produzido na dieta com 60% de concentrado com relação à dieta com 40%, de concentrado. Também foram observadas importantes reduções no NMP de coliformes totais e termotolerantes ao final do processo, independentemente do tratamento testado.Palavras-chave: biodigestor, Canchim, energia, metano, Nelore Anaerobic biodigestion of beef cattle manure: influence of period, genotype and diet ABSTRACT -The objective of this study was to identify possible alterations in the composition and anaerobic biodigestion process of manure from Canchim and Nellore cattle in different periods in feedlot fed with different forage to concentrate ratios. The experiment was carried out in complete randomized design in factorial arrangement with time as sub-divided plot. Plots were established by four treatments: manure from two diets (40% forage and 60% concentrate and 60% forage and 40% concentrate) and two genotypes (Canchim and Nellore) and sub-plots by three periods of manure collection (initial, intermediate and final). The efficiency of the composting process was evaluated by reductions of total solids, volatile solids, the most probable number (MPN) of total and thermotolerant coliforms, chemical and biochemical demand of oxygen, besides the production and potentials of biogas and methane production. There was no effect of genotype or period on manure composting; however, the increase in the forage proportion in the diet promoted the lower efficiency of the process, in which an increase of 26.31% was found for the volume of methane that was produced with diet with 60% concentrate in relation to the diet with 40% concentrate. Significant reductions in MPN of total and thermotolerant coliforms were also observed at the end of the process, regardless of the treatment tested.

Recent Updates on the Use of Agro-Food Waste for Biogas Production

“…Therefore, the extent of biogas production from cattle manure may be affected by management and, in particular, by the diet of the animals as in most cases they are fed on large amounts of substrates containing structural carbohydrates (cell wall components), which result in lower biogas production [63]. On the contrary, feeding cattle diets containing high levels of concentrate increases the biogas production from manure, due to the generation of higher levels of soluble organic-C during anaerobic digestion [63,64]. Accordingly, Costa et al (2016) [65] observed higher biogas yield in young bulls fed on a high concentrate diet (80% concentrate + 20% forage) corresponding to high levels of net energy.…”

“…Animal nutrition also affects the composition of manure-derived bio-fertilizers, altering the levels of the macronutrients N, P, and K [64].…”

Stabilization of confined beef cattle manure: characteristics of produced fertilizers

“…By concentrating cattle in confinement and enhance their food have occurred intrinsic and inevitable consequences as the largest generation and concentration of high pollution potential waste into smaller areas (ORRICO JUNIOR et al, 2012). Intense and concentrated livestock industry activity generates vast quantities of biodegradable waste which must be managed under the appropriate practices to avoid negative impacts on the environment (BERNAL et al, 2009;LUO et al, 2014).…”

“…The use of anaerobic digestion using biodigesters contributes to integration and sustainability of agricultural activities, converting the manure into two energy sources, biogas and biofertilizer (QUADROS et al, 2010;ORRICO JUNIOR et al, 2012).…”

Codigestão anaeróbia dos dejetos de bovinos leiteiros e óleo de descarte

“…Os rendimentos da biodigestão anaeróbia dos dejetos de bovinos, quando utilizados como único componente dos substratos, foram avaliados em ensaio realizado por ORRICO JÚNIOR et al (2012), que verificaram valores de até 370 litros de biogás e 250 litros de metano por kg de SV adicionado. Estes valores podem ser acrescidos, quando os resíduos lipídicos atuam em conjunto com os dejetos de bovinos, incrementando em até 41,1% os rendimentos de biogás e metano (ZHANG et al, 2013).…”