Multicomponent Reactive Transport in an In Situ Zero-Valent Iron Cell

Citations Over TimeTop 10% of 2001 papers

Abstract

Data collected from a field study of in situ zero-valent iron treatment for TCE were analyzed in the context of coupled transport and reaction processes. The focus of this analysis was to understand the behavior of chemical components, including contaminants, in groundwater transported through the iron cell of a pilot-scale funnel and gate treatment system. A multicomponent reactive transport simulator was used to simultaneously model mobile and nonmobile components undergoing equilibrium and kinetic reactions including TCE degradation, parallel iron dissolution reactions, precipitation of secondary minerals, and complexation reactions. The resulting mechanistic model of coupled processes reproduced solution chemistry behavior observed in the iron cell with a minimum of calibration. These observations included the destruction of TCE and cis-1,2-DCE; increases in pH and hydrocarbons; and decreases in EH, alkalinity, dissolved O2 and CO2, and major ions (i.e., Ca, Mg, Cl, sulfate, nitrate). Mineral precipitation in the iron zone was critical to correctly predicting these behaviors. The dominant precipitation products were ferrous hydroxide, siderite, aragonite, brucite, and iron sulfide. In the first few centimeters of the reactive iron cell, these precipitation products are predicted to account for a 3% increase in mineral volume per year, which could have implications for the longevity of favorable barrier hydraulics and reactivity. The inclusion of transport was key to understanding the interplay between rates of transport and rates of reaction in the field.

Related Papers

• → Groundwater Remediation of Chromium Using Zero-Valent Iron in a Permeable Reactive Barrier(1999)9 cited
• → Plaster of Paris containing zero valent iron particles: Designing a permeable reactive barrier, used for remediation of 4-nitroaniline pollution(2021)1 cited
• → Field Evaluation of the Performance and Heterogeneity of a Zero-valent Iron-based Permeable Reactive Barrier for Groundwater Remediation(2007)1 cited
• Permeability losses and its effect on the hydrodynamics and solute transport in zero-valent iron permeable reactive barrier(2016)
• → The Long-Term Viability of a Zero-Valent Iron Permeable Reactive Barrier(2000)