Processo oxidativo avançado (UV/H2O2) como alternativa de pré-tratamento de efluente contaminado pelo agrotóxico clorpirifós.

Brazil has become the world?s top pesticide consumer since 2008. This high consumption rate could lead to serious environmental, sanitary and social risks. Given this, mitigating practices play a fundamental role to reduce the impact caused by pesticide use. Among these, a bioreactor known as Biobed stands out. However, some specific pesticides interfere negatively on that reactor, consequently diminishing its efficiency. In this context, the Advanced Oxidation Process UV/H2O2 proves to be an interesting pretreatment alternative, as it has shown to be effective for different pesticides degradation. The aim of this study was to evaluate UV/H2O2 technology as a chlorpyrifos pretreatment, in order to determine the pre-oxidation conditions. The photodegradation was carried out in an annular reactor, with a high pressure UV lamp. Tests were performed with the initial H2O2 concentration varying from 600 to 2000 mg/L and reaction time from 15 to 80 minutes, while the lamp was powered both with 80 and 125W. The best result was obtained using 125W, H2O2 concentration of 1750 mg/L and 80 minutes of pre-oxidation, providing a 31.5% removal. These results show that UV/H2O2 technology is efficient as a pretreatment technique, resulting in a less concentrated and toxic effluent, so it could be further degraded by bioreactors. Palavras-chave: Pré-tratamento, UV/H2O2 , Biobe