Avaliação do uso da oxidação química in situ em solos ferríferos para remediação de água subterrânea contaminada pela mistura gasolina/etanol

• Ano de defesa: 2016
• Autor(a) principal: Luiza Notini de Andrade
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: ISCO; Etanol; Gasolina; Persulfato de sódio; Meio ambiente; Álcool; Engenharia sanitária
• Link de acesso: http://hdl.handle.net/1843/BUBD-AAFEGR

In Situ Chemical Oxidation (ISCO) has currently been used in Brazil for the remediation of fuel contaminated areas. However, more studies are needed to understand the mechanisms involved on the remediation while considering the specific characteristics of Brazilian gasoline. This study aims to evaluate the use of ISCO on a Brazilian soil (oxisol) and groundwater contaminated by Brazilian commercial gasoline. In order to accomplish these goals, four different stages were proposed: i) evaluate what is the impact of different fractions of anhydrous ethanol on the contaminated plume; ii) select the ideal oxidant for the remediation of groundwater contaminated with Brazilian gasoline ; iii) optimize the use of selected oxidant, analyzing its contact with iron and chelating agents; and iv) evaluate the use of the oxidant on a bench scale soil reactor. Results showed that, in the tested conditions, ethanol did not affect the solubility of BTEX (benzene, toluene, ethylbenzene, xylene) on water. However, ethanol concentrations were directly proportional to the increase of dissolved organic carbon (DOC) into the water. Oxidation tests showed that Na2S2O8, K2S2O8, H2O2 and CaO2 were activated when in contact with ferruginous oxisol. Results also inidicate that all oxidants were able to achieve a minimum of 99.1% of BTEX removal. CaO2 was the oxidant which achieved the highest DOC removal percentage. However, its application presented unwanted outcomes, such as high pH, and chemical precipitation. Thus, Na2S2O8 was selected as the best option of oxidant to be applied in this soil. The presence of soluble Fe2+ and Fe3+ , which are natural from this soil, was effective for the activation of Na2S2O8; and the addition of EDTA was considered unnecessary, once it reacts with Fe2+ e Fe3+, preventing their reaction with the oxidant. Bench scale reactor (control and oxidants) operated receiving contaminated groundwater and results showed that both systems can treat groundwater, but the remediation occurs in different pathways. On the control reactor, intermediates suggest that the process was anaerobic, whereas intermediates formed on oxidant reactor were those which are typically formed in aerobic systems.