PHAST is a three-dimensional simulator developed by the U.S. Geological Survey (USGS) for saturated groundwater flow, solute transport, and multicomponent geochemical reactions. It couples an HST3D-based flow and transport model with the PHREEQC geochemical engine.
This research direction is suited to MSc students interested in hydrogeochemistry, reactive transport, hydrogeology, and environmental risk assessment.
Core Capabilities
- Groundwater Flow & Transport: Three-dimensional saturated flow, advection, and dispersion under steady or transient conditions.
- Aqueous Geochemistry: Speciation, redox reactions, ion exchange, and surface complexation.
- Mineral Reactions: Equilibrium and kinetic mineral dissolution and precipitation, including carbonate reactions and silicate weathering.
- Environmental Applications: Simulates changes in solute concentrations, pH, and mineral reactions to assess water-quality impacts.
Broad Research Suggestions
PHAST serves as an efficient and robust tool for specialized environmental and geoscientific research:
- Shallow Aquifer CO₂ Intrusion: Modeling how dissolved carbon leakage lowers pH and mobilizes trace heavy metals from subsurface sediments.
- Enhanced Rock Weathering (ERW): Quantifying alkalinity generation and carbon sequestration potential when silicate dusts interact with shallow groundwater flow.
- Water-Rock Interaction Feedbacks: Assessing long-term mineral trapping, porosity evolution, and secondary precipitation boundaries along regional flow paths.
- Mine Waste Geochemistry & Remediation: Examining water-rock interactions in sulfide tailings or reactive barriers, modeling acidity attenuation and pathways.
Getting Started & Supervision
PHAST examples cover contaminant decay and sorption, microbial reactions, ion exchange, and sewage plumes. Projects may involve model testing, reactive-transport simulations, or calibration against laboratory or field data.
Model scope:
Single-phase, constant-density saturated groundwater flow; not free-phase CO₂ migration.
Contact:
Dr. Mohammad Nooraiepour (monoo@uio.no)