Monitoring Bioventing of Soil Contaminated with Mineral Oil

In situ bioremediation of a hydrocarbon-contaminated site in The Netherlands will be performed using soil vapor extraction for the vadose zone and groundwater circulation and air injection for the saturated zone. Biodegradation studies in batch incubations were performed to determine nutrient demand and maximal biodegradation rates. Simulation of full-scale bioremediation, was performed using undisturbed soil columns from the site. The biodegradation process in the preinvestigation studies was monitored by measuring contaminant levels, O2, CO2, bacterial numbers, dehydrogenase activity and fluorescinediacetate (FDA) hydrolysis. Dehydrogenases are involved in the respiration process and can be used as a measure of biological activity in soil (Thalmann 1968). FDA is hydrolyzed by a number of different enzymes, such as proteases, lipases, and esterases. Therefore FDA hydrolysis can be used as a measure of total microbial activity in soil (Schnurer & Rosswall 1982).