USGS PHREEQC Aqueous Geochemistry & Speciation (.pqi, .dat)

@modelscript/phreeqc (languages/phreeqc) provides native WebAssembly GLR parsing, ionic strength and Davies / Extended Debye-Hückel activity coefficient calculation, aqueous carbonate/redox speciation, mineral Saturation Index ($\text{SI}$) evaluation, DAEBuilder lowering, and Modelica 3.x projection for USGS PHREEQC hydrogeochemical, brine scaling, carbon mineralization, and water treatment models.

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Supported Extensions & Standards

Extension	Format	Description
.pqi	PHREEQC Input Deck	Keyword data blocks (TITLE, SOLUTION, EQUILIBRIUM_PHASES, REACTION, KINETICS, MIX, SELECTED_OUTPUT, END)
.dat	Thermodynamic Database	Aqueous species (SOLUTION_SPECIES) and mineral solubility (PHASES) database definitions

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Key Capabilities

1. Ionic Strength & Activity Coefficients

• Computes solution ionic strength $I=\frac{1}{2}\sum _i{m}_i{z}_i^2$, charge balance error (% CBE), and ion activity coefficients ${\gamma }_i$ using the Davies or WATEQ Extended Debye-Hückel equation:$${\log }_{10}{\gamma }_i=-A{z}_i^2(\frac{\sqrt{I}}{1+\sqrt{I}}-0.3I)$$

2. Mineral Saturation Indices ($\text{SI}$) & Equilibrium Phases

• Evaluates Ion Activity Products ($\text{IAP}$) and mineral Saturation Indices across carbonate, sulfate, and silicate phases (Calcite, Dolomite, Gypsum, Anhydrite, Barite, Halite, Quartz):$$\text{SI}={\log }_{10}\left(\frac{\text{IAP}}{K_{\text{sp}}(T)}\right)$$identifying supersaturated scaling hazards ($\text{SI}>0$) and undersaturated dissolution regimes ($\text{SI}<0$).

3. DAE Arena Lowering & Modelica Projection

• Lowers aqueous mass-action, charge-balance, and kinetic mineral dissolution/precipitation equations into @modelscript/runtime's DAEBuilder arena and projects them into Modelica 3.x hydrochemical blocks.

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Pre-Flight Diagnostics

10 rules8 error2 warning

Code	Rule	Severity	Message
M9551	ph-out-of-physical-bounds	error	SOLUTION '<solutionNumber>' specifies pH '<pH>' outside standard aqueous bounds [0, 14].
M9552	pe-out-of-redox-stability-bounds	warning	SOLUTION '<solutionNumber>' specifies redox potential pe '<pe>' outside water stability bounds [-15, 25].
M9553	non-physical-temperature	error	SOLUTION '<solutionNumber>' specifies non-physical aqueous temperature '<tempC>' °C (valid range: [0, 350] °C).
M9554	negative-solute-concentration	error	Solute '<element>' in SOLUTION '<solutionNumber>' specifies negative concentration '<concentration>'.
M9555	charge-imbalance-exceeded	warning	SOLUTION '<solutionNumber>' exhibits relative electrical charge imbalance '<value>%' (> 5%) without a 'charge' balance element.
M9556	unknown-aqueous-master-species	error	SOLUTION '<solutionNumber>' references unrecognized aqueous master species '<element>'.
M9557	unknown-equilibrium-mineral-phase	error	EQUILIBRIUM_PHASES '<blockNumber>' references unrecognized mineral phase '<mineralName>'.
M9558	negative-mineral-moles	error	Equilibrium mineral phase '<mineralName>' specifies negative initial moles '<initialMoles>'.
M9559	unresolved-mix-solution	error	MIX '<mixNumber>' references undefined SOLUTION '<solutionNumber>'.
M9560	empty-phreeqc-deck	error	PHREEQC deck contains no SOLUTION, EQUILIBRIUM_PHASES, REACTION, KINETICS, MIX, or database definitions.

Generated from languages/phreeqc/src/errors.ts. All languages →

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CLI Usage

# Validate electrical charge balance, pH/pe bounds, and phase blocks
msx lint GeothermalBrine.pqi

# Parse and inspect PHREEQC keyword blocks
msx parse GeothermalBrine.pqi