Co-digestão anaeróbia dos dejetos de ovinos e glicerina bruta

Abstract

This work was conducted in order to characterize the waste produced by sheep fed two diets: 40% roughage and 60% concentrate (40:60) and 60% roughage and 40% concentrate (60:40) and make co-anaerobic digestion of waste with increasing doses of crude glycerin. The waste produced daily were collected and characterized according to the levels of ST and SV (total solids and volatile) constituents fiber (NDF and ADF), most probable numbers (MPN) of total coliform (TC) and thermotolerant (CTT), chemical demand oxygen demand (COD) and also estimated the coefficient of residue (CR). With these wastes, in combination with increasing doses of crude glycerin (0, 3, 6, 9, 12 and 15% TS) were prepared substrates for the supply of batch digesters bench. In substrates undergoing the co-digestion were observed contents of ST, SV, NDF and ADF, the NMP CT and CTT initial and final, with the objective the evaluate the efficiency of the process in reducing these constituents and also their potential production of biogas. From the influent and effluent were determined levels of nitrogen, phosphorus and potassium (N, P and K) to assess the quality as biofertilizer. No differences were observed for both production and ST contents of the residue between the diets tested, and obtained yields of 0.45 kg and 0.24 kg of manure ST. The contents of VS, COD and NMP CT and CTT were higher in manure from animals fed with higher proportions of concentrate. The CR decreased as the concentration increased in the diet. With respect to the overall production of biogas and the production potential of the substrate, there was a positive linear effect, showing that the extent to which increased additions the crude glycerin inclusions in the substrate, thus indicating that crude glycerin improves the performance of digesters, and even found that there was no influence of diets on the production of biogas. The amount of ST substrate influenced the diets and doses of crude glycerin. The largest concentrations of N, P and K occurred in the effluent (biofertilizer) originating from the manures of animals fed diets with a higher proportion of concentrate (40:60).