ABSTRACT
The aim of this research was to assess the effectiveness of chemical oxidation, Advanced Oxidation Processes (AOPs) and adsorption on granular activated carbon (GAC) for the ex situ remediation of a groundwater contaminated by organolead compounds, including tetraethyl lead (TEL), triethyl lead (TREL) and diethyl lead (DEL). The groundwater of concern was collected from the site of a former tetraalkyllead producing company in Trento (Italy), and showed an average total organic lead (TOL) content about 95.1 microg/L (TEL 0.5 microg/L, TREL 86.4 microg/L, DEL 8.3 microg/L). The main target of the study was to find out which method was more effective in reducing the pollutant content. For this purpose, several laboratory tests were performed, including chemical oxidation tests with different reactants (hydrogen peroxide, modified Fenton's reagent, potassium permanganate, activated potassium persulfate, oxygen and combinations of potassium permanganate and modified Fenton's reagent), AOPs with ozone, UV radiation and hydrogen peroxide and filtration on granular activated carbon. A combination of chemical and physical treatments was also tested, with GAC filtration followed by chemical oxidation. According to the results achieved, the treatments which showed the best remediation performances were: chemical oxidation with modified Fenton's reagent, AOPs with hydrogen peroxide and ozone (perozone), AOPs with hydrogen peroxide and UV radiation, and the combined treatment with activated carbon filtration followed by chemical oxidation with perozone. All these treatments showed a 90% TOL removal, with excellent removals of both TEL and TREL, and final DEL concentrations below 5 microg/L.
Subject(s)
Environmental Restoration and Remediation/methods , Tetraethyl Lead/isolation & purification , Water Pollutants, Chemical/isolation & purification , Chromatography, Gas , Feasibility Studies , Oxidation-ReductionABSTRACT
Este trabalho apresenta os atuais métodos respirométricos voltados ao controle biológico em geral, com técnicas desenvolvidas para a aplicação em tratamentos de águas residuárias, principalmente no controle de processos por lodos ativados e recentes desenvolvimentos do método para a aplicação em sistemas de tratamento por fitodepuração (Wetlands). Descreve novos métodos que foram desenvolvidos no Laboratorio di Ingegneria Sanitaria-Ambientale (LISA) da Università di Trento, Itália. Estes métodos baseiam-se em duas metodologias de laboratório para a aplicação da respirometria em fitoderuração: o primeiro caracteriza a atividade bacteriológica do solo com a finalidade de medir a concentração de O2 na fase gasosa, o outro avalia a concentração de O2 na fase aquosa.
