Successive identification of biodegradation rates for multiple sequentially reactive contaminants in groundwater

At the field scale, the biodegradation rate is usually estimated from analy tical solutions to single species transport with first-order reactions, usi ng measured data as input. Because many contaminants, e.g., chlorinated sol vents, are degraded in a sequential pattern, with degradation products furt her reacting to produce new species, it is of great interest to quantify th e transformation rate of every reaction. The conventional inverse solutions for identifying the transformation rates are limited to single species pro blems. In the present study, we propose a Successive optimization approach to identify the biodegradation rate for each species by using a previously developed analytical solution to multi-species first-order reactive transpo rt using data obtained at the field scale. By specifying a link between ana lytical solutions to sequentially reactive transport problems and optimizat ion methods and assuming constant transport parameters (velocity, dispersiv ities, and retardation factors), the first-order transformation rates are o ptimized successively from parent species to its daughter species. (C) 2001 Elsevier Science B.V. All rights reserved.