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December 10, 2020

USGS developed, in cooperation with the Office of Surface Mining Reclamation and Enforcement, “user-friendly” aqueous geochemical modeling tools to simulate changes in water quality during passive and active treatment of acid mine drainage as described in a new study.

New publicly available software, PHREEQ-N-AMDTreat, can be used with cost-analysis software to identify potential cost-effective strategies for treatment of acid mine drainage. Complementary tools (CausticTitration, ParallelTreatment, TreatTrainMix2) are available to simulate treatment using synthetic chemicals and natural substrates.

Equilibrium aqueous and surface speciation models are combined with kinetic models to simulate water-quality changes during treatment, including:

  • Atmospheric exchange
  • Iron and manganese oxidation
  • Organic carbon oxidation
  • Limestone dissolution

PHREEQ-N-AMDTreat outputs include:

  • pH, specific conductance
  • dissolved metals
  • total dissolved solids
  • mass of precipitated solids


green, orange, trees, wetlands, houses
Silver Creek Aerobic Wetlands treatment system, New Philadelphia, Pennsylvania, with stages simulated using PHREEQ-N-AMDTreat.Credits: Google Earth™, image annotated by Charles Cravotta, USGS


Treatment Stage:

1-Sedimentation Pond
2-Aeration Cascade
3-Aerobic Pond
4-Aeration Cascade
5-Aerobic Pond
6-Riprap Cascade
7-Aerobic Wetland
8-Riprap Cascade
9-Aerobic Wetland


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