Engenharia Agrícola (Dec 2007)
Caracterização e biodigestão anaeróbia dos dejetos de caprinos Characterization and anaerobic digestion of goat manure
Abstract
Quantificar e caracterizar os dejetos gerados por cabras Saanen em quatro categorias de idade e alimentadas com três dietas e na seqüência, e promover a biodigestão anaeróbia dos dejetos constituíram os objetivos deste trabalho. Para a produção de dejetos, foram utilizadas 36 cabras Saanen, com idades entre 2 e 4 (C1), 4 e 8 (C2), 8 e 12 (C3) e acima de 12 meses (C4), alimentadas com as dietas 1 (D1: 80% volumoso (Vol) e 20% concentrado (Con)); 2 (D2: 60% Vol e 40% Con) e 3 (D3: 40% Vol e 20% Con). Foram quantificadas as produções diárias de fezes e urina e seus teores em N, P, K, Ca, Mg, Na, Fe, Cu, Zn e Mn. Com a mistura das fezes e urina de todas as categorias, separadas segundo as dietas, foram abastecidos biodigestores batelada, com capacidade para 4 L de substrato em fermentação. A C1 apresentou menor (PThis study aimed quantify and characterize the manure generated by Saanen goats in four categories of age, fed with three diets and then promote the anaerobic digestion of the manures. Thirty six goats were used with ages between 2 and 4 (C1), 4 and 8 (C2), 8 and 12 (C3) and above 12 months (C4), fed with the diets 1 (D1: 80% forage (Fo) and 20% concentrated (Co)), 2 (D2: 60% Fo and 40% Co) and 3 (D3: 40% Fo and 20% Co). The daily productions of feces and urine and its contents of N, P, K, Ca, Mg, Na, Fe, Cu, Zn and Mn were quantified. A mixture of feces and urine of all the categories of age was used; separated according to the diets, for the supply of batch digesters, with capacity of 4.0 liters of substrate in fermentation. The C1 presented smaller excretion (P<0.05) of feces (164.1 g of MS/animal per day) and the smallest food consumption (362.16 g MS/animal per day). The largest concentrations of N, P, K, Ca, Mg and K occurred in the feces and urine generated by goats of C4 and fed by D3. The prepared substrate with manures originating from of D3 presented 45% of reduction in the contents of volatile solids (VS). The prepared substrate with manures of animals fed with D3 produced more biogas (P<0.01) for kg of total solids and VS added.
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