Potentials of biogas production from young bulls manure fed with different diets

Abstract

Physical and chemical characteristics of manure are modified by different animal production systems. In cattle feeding system for young bulls there is an inversion of the proportion between forage and concentrate. In other words, the animals receive a smaller amount of forage compared to the traditional system. These changes in the manure characteristics involve changes in the treatment systems. The aim of this study was to determine the potential production of biogas of batch digesters fed with manure from young bulls that received two diets containing different proportions between forage and concentrate, with or without inoculums and submitted to three levels of temperature (25, 35 and 40 0 C). The evaluated parameters were total solids (TS) and volatile solids (VS) reduction and biogas potentials production. The digesters fed with manure from animals that received the diet 2 (80%C + 20% R) showed the largest reductions of TS and VS. About the potentials of biogas production there was interaction between the factors diet and inoculums, but no effects of temperatures. The treatment content manure from animals fed with diet 2 without inoculums presented the greatest potential of biogas production per kg of TS added (0.2123 m 3 ).KEYWORDS: batch digesters, temperature levels, inoculums. POTENCIAIS DE PRODUÇÃO DE BIOGÁS DE DEJETOS DE NOVILHOS SUPERPRECOCES ALIMENTADOS COM DIFERENTES DIETASRESUMO: Os diferentes sistemas de criação animal no modelo industrial promovem alterações físicas e químicas nas dejeções. Na engorda de bovinos no modelo de confinamento para novilhos superprecoces, tem-se uma inversão na proporção entre volumoso (V) e concentrado (C), ou seja, os animais recebem quantidade inferior de volumoso quando comparado ao sistema tradicional de confinamento, o que implica modificações das dejeções e, consequentemente, no sistema de tratamento utilizado. Neste trabalho, objetivou-se determinar os potenciais de produção de biogás em biodigestores de bancada operados no sistema batelada, alimentados com dejetos de novilhos superprecoces que receberam duas dietas diferenciadas pelas proporções entre V e C, contendo ou não inóculo na composição do substrato e submetidos a três níveis de temperatura (25º, 35 e 40° C). Os parâmetros avaliados foram: redução de sólidos totais (ST), redução de sólidos voláteis (SV) e potencial de produção de biogás. Os biodigestores alimentados com dejetos provenientes de animais que receberam a dieta 2 (80%C + 20%V), apresentaram as maiores reduções de ST e SV. Quanto aos potenciais de produção de biogás, houve interação entre os fatores dieta e inóculo, porém não se observou efeito da temperatura. O tratamento contendo os dejetos provenientes de animais alimentados com a dieta 2, sem a utilização de inóculo, apresentou o maior potencial de produção de biogás por kg de ST adicionado (0,2123 m 3 ).

A highly concentrated diet increases biogas production and the agronomic value of young bull’s manure

“…Biogas production from cattle manure is highly influenced by manure chemical composition (Orrico et al, 2010). 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 (Orrico et al, 2010(Orrico et al, , 2012Costa et al, 2013). Animal nutrition also affects the composition of manure-derived biofertilizers, altering directly the levels of the macronutrients N, P, and K (Orrico et al, 2012).…”

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

“…Other authors [47] found a content of lignin in dairy manure of 7.95%, while in pig and poultry manure it was 1.83% and 1.7%, respectively. 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].…”

“…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.…”

Evaluation of anaerobic digestibility of energy crops and agricultural by-products

“…Studies have noted that manure characteristics and biogas potentials are reliant on a series of factors: animal species, diet, protein and fibre content, age, housing and more (Kelleher et al, 2002). Costa et al, (2013) found that cows fed with diets richer in concentrate (protein mixed with maize silage) as opposed to forage had lower levels of fibre and resulted in higher biogas yields in AD. Besides, livestock manure as a feedstock for AD can be precarious as it contains a mixture of feathers or hair, spilled feed, bedding and mortality, which leads to a great variability in reported biogas and CH4 yields from previous research ( Table 1).…”

“…can be attributed to the high lipid and protein content in fish waste which takes longer for bacteria to degrade but in turn produces high yields (Costa et al, 2013). Nges et al, Table 1).…”