ON-LINE MONITORING OF BIODEGRADATION IN SOILS: MICROCOSM AND COLUMN EXPERIMENTS

摘要

The objective of the study described in the present paper was to develop a model-based estimator (software-sensor) of biodegradation in unsaturated soil. This would allow real-time assessment of the efficiency of treatment bioprocesses, such as bioventilation and biopile, and eventually permit optimization through the implementation of control strategies. Based on a reduced-order model, an asymptotic observer has been designed to estimate on-line the contaminant concentration, using carbon dioxide measurement. The software-sensor has been confronted with the experimental results of biodegradation in microcosms and in column. Hexadecane was used as the model compound, representing petroleum hydrocarbons. The asymptotic observer was able to predict hexadecane depletion with an error on the overall time trajectories of less than 5% and 8% for the experiment in microcosm and in column, respectively. These results are very encouraging with respect to the potential for on-line assessment of the performance of treatment bioprocesses in unsaturated soils.