Modeling multiphase migration of organic chemicals in groundwater systems--a review and assessment.

Abstract

Over the past two decades, a number of models have been developed to describe the multiphase migration of organic chemicals in the subsurface. This paper presents the state-of-the-art with regard to such modeling efforts. The mathematical foundations of these models are explored and individual models are presented and discussed. Models are divided into three groups: a) those that assume a sharp interface between the migrating fluids; b) those that incorporate capillarity; and c) those that consider interphase transport of mass. Strengths and weaknesses of each approach are considered along with supporting data for model validation. Future research directions are also highlighted.

Memory Effect of Aquatic Biofilms in the Partitioning of Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) in Water Streams

“…This is in agreement with the model presented here. 2 packed bed column reactor [64] 0.9-1 mulch biofilm barrier [65] pyrene 0.6 on phenanthrene crystals [63] 0.2 packed bed column reactor [62] 0.8 mulch biofilm barrier [65] Declor 103 5.6 Immobilized bacteria in alginate [66] 4-CB cogeners 10 Biofilm on glass beads [67] Kaneclor 300 [10][11][12][13][14][15][16][17][18][19][20] Immobilized bacteria in alginate [68] Aroclor 1260 1.8-10 Biofilm in fluidized bed reactor [69] IV. DESORPTION MODEL The remobilization of pollutants from biofilms can occur via detachment of the biofilm matrix from the substratum or via diffusional desorption of the pollutant molecules into the water column.…”

“…Biofilms are microbial aggregates, in which bacterial cells are enveloped by a matrix of self-produced extracellular polymeric substances (EPS) such as polysaccharides, proteins, lipids, humic acids and DNA [11]. In rivers and water streams, microbial biofilms can absorb, accumulate and biodegrade organic pollutants [12]- [15]. Polar hydrophilic pollutants are accumulated in biofilms due to strong electric interactions, whereas the sorption of hydrophobic organic pollutants in the EPS matrix of biofilms is mostly diffusive [16] and driven by the establishments of weak interactions between the functional groups of the EPS polymers and the sorbed molecules.…”

Modeling for Surfactant-Enhanced Groundwater Remediation Processes at DNAPLs-Contaminated Sites

“…The formulation method expressed in Equation (1a) represents a compositional approach to simulate multiphase flow in the subsurface, in which the conservation equations are developed by summing the mass balance equations for each constituent over all of the phases (Abriola and Pinder 1989). The source/sink term R k in Equation (1a) include all the changes in volume of component k from reaction and well injection/production.…”

“…The solution method used for the flow system in the model is analogous to the implicit pressure-explicit saturation method, which is well-established in the petroleum engineering literature (Abriola and Pinder, 1989). The flow equations are solved using a block-centred finite-difference scheme.…”

Assessment of human exposure to chemicals from Superfund sites.

“…Mathematical models have been developed to quantitatively describe the movement ofdissolved, gaseous, and liquid organics in the subsurface environment (11,12). However, to apply these models successfully, more understanding is needed of the processes governing the movement of NAPL in both the saturated and unsaturated zones and partitioning of compounds between NAPL, air, water, and soil surfaces.…”