Remediação de solos da formação São Paulo contaminados por vapores de gasolina.

This work aims to present and to discuss a case study of identification and emergency remediation of volatile organic compounds, occluded in a sand layer of the Sao Paulo Tertiary Formation, as a result of the leakage of fuel tanks of a service station. The adopted remediation technique was in situ soil vapor extraction (SVE) and offgas treatment for adsorption in activated carbon filters. Selection, design, commissioning, operation and shutdown processes of SVE technology followed literature methodologies, which were adapted to local conditions. Remediation efficiency monitoring was based on the initial quantification of light total petroleum hydrocarbons in the subsoil, through gas chromatography and mass spectrometry techniques, and on measurement of the volatile concentrations and respective explosive contents in the field. The result of the laboratorial campaign presented strong indications that the local contamination proceeded from combustible gasoline and it indicated the occurrence of benzene in concentrations higher than the adopted reference. Field measurements showed fast decline of the volatile concentrations and explosive contents with the SVE technology operation, fact that indicated low occurrence of mass transfer limitations in the place. The fact that remediation goals were achieved with few air exchanges, parameter back-analyzed from geologicgeotechnical tests, contributed to reinforce such hypothesis. Thus, SVE technique can be considered efficient for volatile remediation and explosive risks reduction, for areas with characteristics similar to the studied one. Key-words: Petroleum Hydrocarbons. Volatile Organic Compounds. Explosive Content. Gases Flow. Soil Vapor Extraction Technology. Sao Paulo Formation. Air Intrinsic Permeability. Photoionization Detectors. Catalytic bead detectors. LISTA DE ILUSTRACOES