ABSTRACT
The mineralization rate of the remaining petroleum constituents in soil may become immeasurable. Yet, chemical analysis of the soil may indicate that the soil is still polluted by petroleum hydrocarbons. To get an insight into the overall biodegradation rate of petroleum hydrocarbons, studies were carried out at Delft Geotechnics with soil columns contaminated with a fuel oil. Even when conventional soil sampling is carried out according to the laws of statistics, it still carries an element of uncertainty. A reliable indicator for in situ bioremedial cleanup is the subsidence in oxygen consumption to very low levels. As soon as the oxygen consumption (and the carbon dioxide production) becomes immeasurable or indistinguishable from unpolluted areas, it is time to take confirmation borings which can be used to analyse the composition of the petroleum residuals in soil relative to the beginning of the remedial operation.
