Biodegradation monitoring of toluene by geo-electrical measurements and CO2 analyses : a column study

International audienceHydrocarbon contaminated aquifers can be successfully treated through biodegradation. However, in situ sampling for monitoring the treatment is expensive, invasive and can be insufficient to obtain a robust monitoring as the information provided is restricted to vertical profiles at discrete locations. An alternative method was tested in order to improve the efficiency of the monitoring. An electrical geophysical method, Spectral Induced Polarization (SIP), was combined with CO2 analyses, concentration and carbon isotopic ratio, to monitor toluene aerobic biodegradation in columns. Microbial activity was characterized by CO2 production, carbon isotopic fractionation and also by an evolution of the SIP response in correlation with biofilm growth and the associated bacterial activity (CO2 production as a consequence of toluene biodegradation). Combination of geophysical measurements with CO2 analyses are proving to be highly promising for real field scale biodegradation monitorin