A vadose column method designed to simulate the removal of BTX during bioventing was developed in this paper.A soil column without microorganism was used as a control measure for removal of BTX by volatilization merely.During the last period of venting

the long term tailing behavior was found in the control experiment

indicating that venting by itself might be inefficient in achieving a complete cleanup.At the end of experiment

the concentration of residual BTX in bioventing soil column was much smaller than that in the control one due to biodegradation. To determine the role of bioconversion and physical removal of BTX from soil

air and N2 were used

respectively

as flushing gases at a flowrate of 5.0 ml8226;min-1.Mass balance analysis of BTX and CO2 indicated that the volatilization-to-biodegradation ratio of benzene

toluene and p-xylene during bioventing experiment are about 17.8%

30.0% and 32.3%

respectively.Moreover

the iteractions among the BTX contaminants were also explored by batch experiments.Results showed that benzene and p-xylene degradation were accelerated while toluene was being degraded

and the presence of p-xylene increased the lag period for degradation of benzene and toluene.