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Reactive Transport in the Saturated Zone: Case Histories for Permeable Reactive Barriers

Ground Water Hydrology

  1. Len Li,
  2. Craig H. Benson

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.gw941

Water Encyclopedia

Water Encyclopedia

How to Cite

Li, L. and Benson, C. H. 2005. Reactive Transport in the Saturated Zone: Case Histories for Permeable Reactive Barriers. Water Encyclopedia. 5:518–524.

Author Information

  1. University of Wisconsin-Madison, Madison, Wisconsin

Publication History

  1. Published Online: 15 JUL 2005

Abstract

This chapter describes comparisons between predictions made with a reactive transport simulator and geochemical conditions observed in three permeable reactive barriers (PRBs) employing zero valent iron (ZVI) as the reactive medium. The emphasis is on reactions involving common ions in groundwater that form minerals that may block the pore space in a PRB. Two common public-domain programs, MODFLOW and RT3D, were combined to form the simulator. A geochemical algorithm was developed for RT3D to simulate geochemical reactions occurring in PRBs. Comparisons between model predictions and field data are presented for three PRBs. Good agreement was obtained between predicted and measured pH and common ion concentrations by adjusting the rate coefficients within ranges reported in the literature. However, sensitivity analyses showed that predictions made with the simulator are sensitive to the rate coefficients used as input. The field data sets also were too sparse to determine whether the simulator accurately predicts the rapid changes in geochemistry occurring near the entrance face of PRBs.

Keywords:

  • permeable reactive barriers;
  • reactive transport;
  • reaction kinetics;
  • chemical transport;
  • groundwater;
  • contaminant transport;
  • minerals;
  • fouling