Avaliação de um reator biológico aerado para o tratamento de efluentes contaminados por agrotóxicos.

Abstract

The agricultural process has undergone significant changes in the 50s that mainly contemplated the extensive use of pesticides to control pests and diseases. However, the use of these substances generates contaminated effluents that may significantly impact the environment, which makes it essential to use methods for treat them and reduce their toxicity, such as the biological treatment. The aim of this study was to evaluate a biological treatment system combining aeration and goat manure in the biodegradation of wastewater contaminated with pesticides, in order to reuse this effluent as a biofertilizer. The work was conducted in two stages, the first, consisted of evaluation biological treatment adopted by a grape-producing farm in the São Francisco Valley and the second stage, gazed a study in laboratory scale with synthetic sewage using aerated biological reactor. In the first stage, the effluents and the organic syrup were collected in aerated tanks in the grape-producing farm. Were asked the following analyzes, physical-chemical and microbiological in effluent samples and organic syrup; pesticide residues in the goat manure and effluent; toxicity tests with the effluent before and after treatment. The treatment was able to biodegrade the fungicide cyproconazole. In the second step the experimental design was a 2x2 factorial design with three replications. The synthetic effluent prepared with the insecticide imidacloprid was placed in a reactor, followed by addition of goat manure and if the system remained under constant aeration by the aeration tank pumps. Temperature, dissolved oxygen, nitrogen and TOC were monitored. Microbiological analyzes were performed in the effluent and pesticide residues in the effluent and manure. Studies of this nature make an enormous contribution to science and the São Francisco valley, as they provide an alternative treatment method for leftover syrup and cleaning water for spraying equipment.