A semi-analytical solution for simulating contaminant transport subject to chain-decay reactions

Determination of rate constants and branching ratios for TCE degradation by zero-valent iron using a chain decay multispecies model

“…A semi-analytical solution for multispecies transport with first-order chain-decay reactions developed by Sudicky et al (2013) was used to evaluate reaction rate constants and branching ratios during the TCE reduction by ZVI in each of the columns. The chain-decay multispecies model (CMM) takes into account different transport and reaction parameters for each individual species such as retardation factors, diffusion coefficients, decay constants and degradation pathway branching ratios.…”

“…In its current form, the CMM model is capable of simulating multi-reaction pathways with up to seven species and four decay generations in multidimensional groundwater flow systems. In terms of its reasonability and robustness, the model has been verified with various numerical simulators (e.g., HydroGeoSphere (Aquanty Inc., 2013), CompFlow-Bio (Unger et al, 1996), and PHREEQC-2 (Parkhurst and Appelo, 1999)) for various simulation conditions (e.g., straight-and multi-chain decays with different retardations) Sudicky et al, 2013). The CMM model is based on the advective-dispersive-reactive transport of a contaminant species i undergoing first-order chain-decay reactions as follows:…”

“…There is still no sufficient information whether or not rate constants and branching ratios may change over time upon long-term operation of a PRB or through natural attenuation. Sudicky et al (2013) recently developed a multispecies model that can handle reaction kinetics for individual species and various reaction pathways in multiple dimensions. The model has an additional benefit in that it can be readily used for Monte Carlo probabilistic simulations of contaminant transport to account for uncertainties in groundwater velocity and various other fate and transport parameters.…”

“…In this study, we applied the model of Sudicky et al (2013) to data obtained from controlled laboratory column experiments in order to derive reaction rate constants and branching ratios for reactions with sequential and parallel reaction pathways. The model, once validated, will provide a convenient tool for the design of ZVI PRBs to treat chlorinated organic compounds.…”

The transport processes of soluble contaminant in unsaturated soils under pond infiltration

“…Maraqa et al (2014) explored the effects of experimental conditions on fitting single-rate sorption models to the results of soluble transport experiments which are affected by heterogeneous sorption kinetics. Sudicky et al (2014) presented semi-analytical solutions to simulate three-dimensional contaminant transport subjected to first-order chain-decay reactions; this solution can be used in the transformation of contaminants into daughter products, leading to decay chains consisting of multiple contaminant species.…”