GMS:Chemical Reaction Package

The Chemical Reaction Package dialog

The Chemical Reaction Package dialog is used to solve the concentration change due to chemical reactions. Chemical reactions can be defined for the MT3DMS, MT3D-USGS, PHT3D, and SEAM3D models. The dialog is reached through the model menu using the Chemical Reaction Package command which is only available once the package has been activated in the Packages dialog and species have been defined. The chemical reactions include linear or nonlinear sorption isotherms and first-order irreversible rate reactions (radioactive decay or biodegradation).

The dialog has the following options:

• Sorption – Select one of the following methods:
  • "(none)"
  • "Linear isotherm"
  • "Freundich isotherm"
  • "Langmuir isotherm"
  • "First-order kinetic sorption (non-equilibrium)"
  • "Dual-domain mass transfer (without sorption)
  • "Dual-domain mass transfer (with sorption)"
• Kinetic rate reaction – Has the following options:
  • "(none)"
  • "First-order irreversible kinetic reaction"
  • "Zero-order reaction (decay or production)"
• Variable input
  • Layer by layer
  • Cell by cell
• Specify IC of sorbed phase
• Layer – Specifies layer to apply chemical reaction.
• Bulk density
• Immobile porosity