Co-digestão de excretas de suínos associadas à doses crescentes de glicerina bruta

Abstract

The Brazilian grain production will increase from 184.2 million tonnes to 222.3 million over the next ten years. Part of this growth is due to the production of biofuels incentive policies, such as biodiesel that makes up 3% of the diesel consumed in the country. The livestock sector is also part of the demand for grain and meat production is projected to increase to 9.3 million tons, representing a increase of 34.9% in the production of meat in 2012/2013. Despite the favorable economic data, such sector concern from an environmental point of view, particularly as regards the production of waste: crude glycerin and animal feces. Anaerobic digestion is a technique that lets you recycle organic waste and generate energy as methane. In anaerobic conditions the co-digestion has been explored with greater emphasis on animal production systems that use the excreta associated with other waste that can stabilize the process. Anaerobic co-digestion is influenced by several factors, including the retention time of the material in biodigesters. The aim of this work was to monitor the performance of anaerobic co-digestion process excreta of pigs associated with increasing doses of crude glycerin, adopting different hydraulic retention times (HRT). The design was completely randomized in a 3x4 factorial design, three HRT (10, 17 and 24 days) and four crude glycerin rates (0, 5, 10 and 15% of total solids), with four replicates per treatment. The biogas production potential for volatile solids added showed a quadratic effect on TRH 17 and 24, showing how optimal doses 5.5 and 5.9% crude glycerin, respectively. Values of COD reductions significant effect of HRT, 24 days old providing the best results. Over 99% reductions were observed for coliforms, but there was no statistical difference between treatments. Adding 5-6% crude glycerin, in the largest HRTs, was more effective in producing biogas and 24 days HRT showed the greatest reductions of solids, COD and coliforms from the co-digestion with feces swine.