Bioremediation of an area contaminated by a fuel spill

In order to decontaminate a large area of restricted access contaminated by a fuel spill, laboratory and field studies were developed in two steps: (a ) monitoring of the laboratory experiment on bacterial growth under aerobic and anaerobic conditions with and without addition of nutrients; and (b) u se of the best conditions obtained in (a) for the decontamination of the so il. A hydraulic barrier was installed both to clean the aquifer and to avoi d migration of hydrocarbons as a consequence of their solution in the groun dwater and subsequent displacement. The objective was to create an ideal en vironment for the treatment of the affected area that favoured the growth o f the indigenous bacteria (Pseudomonas and Arthrobacter) that biodegrade th e hydrocarbons. Monitoring of the changes in the total concentration of pet roleum hydrocarbons in the soil subjected to bacterial action was performed by gas chromatography. In a field study, the progress of biodegradation of hydrocarbons was evaluated in situ by changes in subsurface CO2/O-2 levels by means of an analyser equipped with an infrared detector. Biostimulation and oxygen were the most influential factors for the biodegradation of the hydrocarbons. The use of bioventing of the soil was shown as an excellent technology to promote in situ bioremediation of the polluted area.