Codigestão anaeróbia de resíduos bovinos e suínos: caracterização química e produção de biofertilizante para uso em cultura de milho

Abstract

When discussing environmental contamination, just remember the amount of domestic and urban waste that are generated in towns and cities, which often do not receive any treatment. However, problems of environmental contamination are linked to agriculture, where organic waste with high potential polluters is generated. This way, the project had the objective of studying the anaerobic codigestion process of cattle and pig waste from the swine production systems and dairy farming activity, as an alternative to the treatment of these kinds of matrices, as well as to investigate the efficiency of biofertilizer matrices produced from the waste in cultured maize. For this, samples of manure from cattle and pigs were collected for characterization and subsequent use in the tests with different treatments. Then, the preparation of samples for the tests using the different inocula were made (in natura, inoculum of sanitation and inoculum isolated from bovine manure), in order to evaluate the degradation of waste via anaerobic codigestão. In each test mentioned twenty treatments were made, via 2³ factorial design with six central points, where the input variables: time, fraction of solids and mixing ratio; and the response variables (dependent): pH, ratio AV/AL, moisture, solids, ratio SV/ST, reduction of total solids, COD, reduction of COD, total nitrogen, phosphorus and potassium. It was made after the kinetic study of the process, using the test in natura mix ratio of 75% in swine manure and 25% in cattle manure with solid fraction of 8.9% by the Tukey test. After stabilization of the biomass used, there was the application of biofertilizers in crop maize compared with commercial fertilizer (urea), verifying the growth and development of this culture. In factorial design was completed by Tukey analysis and considering the importance of each variable response that the test in natura presented the best operating conditions, because it had the largest number of variable responses being considered satisfactory ratio as AV / AL, ratio SV / ST and COD reduction. It was observed during the kinetic study that biomass showed stabilization next to twenty days of treatment, indicating the degradation of organic waste in codigestão and biofertilizer production, which is more stable and less polluting to the environment, being used as an option in process fertilization of agricultural crops such as maize. Regarding the use of biofertilizers (40 kg.ha-1), this similarity was noted compared to urea (40 kg.ha-1) for the cultivation of maize and it may be an interesting alternative for allocation of waste, reducing environmental pollution caused by improper handling.