Analytical model for heterogeneous reactions in mixed porous media
- Univ. of Florida, Gainesville, FL (United States). Dept. of Civil Engineering
- Armstrong Lab., Tyndall AFB, FL (United States). Environmental Research Lab.
- EPA, Athens, GA (United States)
The funnel/gate system is a developing technology for passive ground-water plume management and treatment. This technology uses sheet pilings as a funnel to force polluted ground water through a highly permeable zone of reactive porous media (the gate) where contaminants are degraded by biotic or abiotic heterogeneous reactions. This paper presents a new analytical nonequilibrium model for solute transport in saturated, nonhomogeneous or mixed porous media that could assist efforts to design funnel/gate systems and predict their performance. The model incorporates convective/dispersion transport, dissolved constituent decay, surface-mediated degradation, and time-dependent mass transfer between phases. Simulation studies of equilibrium and nonequilibrium transport conditions reveal manifestations of rate-limited degradation when mass-transfer times are longer than system hydraulic residence times, or when surface-mediated reaction rates are faster than solute mass-transfer processes (i.e., sorption, film diffusion, or intraparticle diffusion). For example, steady-state contaminant concentrations will be higher under a nonequilibrium transport scenario than would otherwise be expected when assuming equilibrium conditions. Thus, a funnel/gate system may fail to achieve desired ground-water treatment if the possibility of mass-transfer-limited degradation is not considered.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 287533
- Journal Information:
- Journal of Environmental Engineering, Vol. 122, Issue 8; Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
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