SIMULATING BIODEGRADATION USING PARTICLE TRACKING METHOD

An accurate mathematical description of the fate and transport of chemical species

is critical for designing groundwater remediation systems. Recent studies have

demonstrated that the typical method of adding mass-action type reaction terms to

the advection-dispersion (and diffusion) equation overestimates the in-situ field-scale

reaction rates. An alternative method based on a purely Langragian particle tracking (PT)

theoretical development, successfully reproduced the results of bimolecular reaction

(A+B --> C) from two benchmark experiments. In this numerical method, the reactants

are represented by particles. The reactions are determined by a combination of two

probabilities that govern whether: 1) reactant particles occupy the same volume over a

short time interval, and 2) two collocated particles favorably transform into a reaction.

We extend the application of the PT method to biodegradation, which is characterized

by a more complex chemical kinetics, for instance, Michaelis-Menten (Monod) kinetics.

The advantage of the PT method is that it explains the variation of reaction rate (Monod

kinetics) based on mixing-controlled particle collisions instead of using empirical

parameters.