Evaluation of xylene bioventing in a residual granitic soil remediation

Abstract

In the present study a residual granitic soil contaminated with xylene was submitted to bioventing tests.The most adequate range for the growth of the microbial consortia, developed from a soil sample collected in a refinery area, was determined by extensive kinetic studies in flasks, using different contaminant concentrations. The selected xylene degrader consortium of bacteria was used in custom-built soil bioventing columns, subject to a contamination level previously established by kinetic studies, a constant air flow and room temperature. Control was done simultaneously by respirometry, measuring O2, CO2 and moisture, by Gas Chromatography and by measuring biomass, counting colonyforming units by spreading on Petri plates. Bioventing results a mathematical model contemplating different kinetics rates for the volatilized and for the biodegraded fractions of the contaminant.