Tratamento de resíduos orgânicos de pequenos abatedouros de bovinos através da compostagem

Abstract

A trial was conducted to evaluate the technical viability of composting for treating inedible residues from bovine slaughter house. Physical and chemical transformations of biomass were monitored during the whole period of composting. The system had two stages. The first one took place at two composting cells and the second one in an impermeable building, were two piles, one from each composting cell was built. Two treatments were evaluated: T1 mixture of wood sawdust and wood shavings with inedible residues of bovine slaughter house; and T2 wood shavings mixed with inedible residues of bovine slaughter house. Each treatment had five replications. Sampling for analysis of physical and chemical composition of biomass was obtained at 30, 60, 90, 120 and 150 days of composting. Biomass temperature was recorded once a day during the whole experimental period. Treatment means were compared through repeated measure procedures with LS Means test (P<0.05). Additionally, linear, quadratic and cubic equations were estimated for temperature of composting. The following variables were measured: dry matter, organic matter, ash, nitrogen, carbon, C/N ratio, phosphorus, potassium, magnesium, pH and biomass temperature. Small variation was observed among the treatments during the whole composting process. Only a numerical variation was observed as composting progressed, not only within but also among treatments. The higher significant difference was obtained for the final content of humidity and pH for both treatments (P<0.05) at the end of experimental period. Apparently, the air environmental temperature had no influence on biomass temperature during the whole composting period. Composting is an alternative for economic and ecologically correct disposing of inedible bovine slaughter house residues even at the end of just 90 days. Therefore, composting ought to be used by bovine producers and industry, helping achieving its environmental sustainability.