Abstract
Brazil has become the world's largest consumer of pesticides since 2008, which can lead to serious environmental, health and social risks. Practices to mitigate the impact caused by pesticide effluents in rural areas have increased in importance, given the impossibility of carrying out conventional treatment of these residues in industrial plants. Among these practices, the use of fixed-bed bioreactors, known as Biobed, stands out in reducing point contamination. It is known that this model of reactor faces difficulties in the biodegradation of some pesticides, including the fungicide tebuconazole, which can negatively interfere with its efficiency. This problem needs to be addressed in order for the biological system to meet the required environmental safety parameters. And one of these alternatives is the use of the UV/H2O2 Advanced Oxidation Process as a pre-treatment, so the pesticide effluent can reach lower concentrations before being disposed in a Biobed. The aim of this work was to evaluate the influence of the pre-treatment in relation to the Biobed. Pre-treated and untreated effluents were applied in the bioreactor in the form of columns, being evaluated at 1, 84 and 168 days after contamination, through gas chromatography that determined the concentration of the pesticide residues. The results showed that the pre-treatment fulfilled its role of reducing effluent pesticide concentration (68.1 %), without inhibiting the biological action of the Biobed reactor still serving to increase the efficiency of the tebuconazole degradation, in relation to the contaminated reactors without pre-treatment. These results allow the recommendation of Biobed systems usage with oxidative pre-treatment UV/H2O2.
