Scaling kinetics of organic compounds degradation: laboratory values extended to field sites

摘要

In this paper we study the degradation kinetics of chlorinated solvents in the laboratory and in the field. Microcosms were prepared from groundwater from a field site and showed biodegradation of PCE to ethene only when organic matter (as propionate) was added to the microcosm. In the field, the same geochemical model was applied in conjunction with a transport model to simulate chlorinated solvents and electron acceptors concentrations. Due to the uncertainty on the size of the degradation zone (reducing area) several values of kinetic constant and several models might be used to fit the measured field data. A model using kinetic values obtained in the laboratory suggests that degradation only occurs in a small area. From this study and data from other sites, two major conclusions can be drawn: (i) at most sites the area where degradation occurs seems to be fairly small, and (ii) for chlorinated solvents plume modelling, working on electron acceptors spatial distribution is as important as assessing the kinetic degradation rates.