HR: 0830h
AN: H11D-0894    [PDF]
TI: Analytical Modeling of A By-product Transport in Chain Reactions
AU: * Sun, Y
EM: sun4@llnl.gov
AF: Lawrence Livermore National Laboratory, PO Box 808 L-646, Livermore, CA 94550 United States
AU: Lee, K
EM: lee23@llnl.gov
AF: Lawrence Livermore National Laboratory, PO Box 808 L-646, Livermore, CA 94550 United States
AU: Buscheck, T A
EM: buscheck1@llnl.gov
AF: Lawrence Livermore National Laboratory, PO Box 808 L-646, Livermore, CA 94550 United States
AB: Many chemical reactions of contaminants in the subsurface involve complex reaction pathways and networks. As one of those reaction networks, chain-reactions can be found in radionuclide decay, denitrification, biodegradation of chlorinated solvents, etc. For example, this reaction pattern can be illustrated by the biodegrdation of tetrachloroethylene (PCE) and trichloroethylene (TCE). PCE reacts to produce TCE and TCE reacts to form dichloroethylene (DCE). DCE will further reacts to form vinyl chloride (VC) and finally VC reacts to produce thylene (ETH). During the chain reactions, by-products, such as chloride in PCE reaction chain, can be produced in groundwater. For this reason, by-prodcut concentrations in the contaminant plumes are elevated relatively to ambient concentrations. Because of the neutral chemical behavior of some by-products, they can be treated as indicators to identify the sources of contaminants and to estimate reaction rates. Often, a single by-prodcut is produced from multiple steps in a reaction chain. Then, the partial differential equation for by-product mass balance is coupled by multiple reactants. This makes it difficult, if not impossible, to derive analytical solutions using integral transforms. Instead, we conduct singular value decomposition (SVD) analytically and develop a closed-form solution of a by-product transport in multiple chain reactions. In achieving the analytical solution, all reactions are assumed to be first-order and the system is assumed to be homogeneous and isotropic.
DE: 1800 HYDROLOGY
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting