PHREEQC! A Graphical User Interface to the Geochemical Model PHREEQC PHREEQC! Version 2 is a complete Windows-based graphical user interface to the geochemical computer program PHREEQC (Version 2). PHREEQC! can be used interactively to perform all the modeling capabilities of PHREEQC speciation, batch-reaction, one- dimensional (ID) reactive-transport, and inverse modeling. Applications: Mine drainage Radioactive-waste isolation Contaminant migration Natural and engineered aquifer remediation Aquifer storage and recovery Water treatment Natural systems Laboratory experiments Features of the interface: Compatible with Windows 95 and 98, Windows NT 4.0, Windows ME, Windows 2000, and Windows XP Automated installation using InstallShield Interactive access to all of the capabilities of PHREEQC create and modify input data files, run simulations, and display results Modeling capabilities: Aqueous, mineral, gas, surface, ion- exchange, and solid-solution equilibria Kinetic reactions ID diffusion or advection and dispersion with dual-porosity medium A powerful inverse modeling capability allows identification of reactions that account for the chemical evolution in observed water compositions Extensive geochemical databases Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. PHREEQC! Version 2 PHREEQC] Version 2 is a computer program for simulating chemical reactions and transport processes in natural or contaminated water. PHREEQC! provides all of the capabilities of the geochemical model PHREEQC (Parkhurst and Appelo, 1999), including speciation, batch-reaction, 1D reactive- transport, and inverse modeling. Data for PHREEQC are entered through a series of keyword data blocks, each of which provides a specific type of information. For example, the SOLUTION keyword data block defines the chemical composition of a solution. PHREEQC! provides tabbed dialog boxes for each PHREEQC keyword. Figure 1 shows the main screen of PHREEQC! and the SOLUTION keyword dialog box. Speciation Modeling Applications Speciation modeling is useful in situations where the possibility of mineral dissolution or precipitation needs to be known, as in water treatment, aquifer storage and recovery, artificial recharge, and well Description Speciation modeling uses a chemical analysis of a water to calculate the distribution of aqueous species by using an ion-association aqueous model. The most important results of speciation calculations are saturation indices for minerals, which indicate whether a mineral should dissolve or precipitate. Keyword data blocks used in speciation modeling include: SOLUTION define the chemical composition of a solution. SOLUTION SPREAD define the chemical composition of multiple solutions in a spreadsheet format. Batch-Reaction Modeling Applications Batch-reaction modeling can be applied to problems in laboratory, natural, or contaminated systems. The reaction capabilities of PHREEQC have been used frequently in the study of mine drainage, radioactive- niection. SSSSM J general Delaut J He Ed* {jew Options Window fjelp 0&O9 £ * SEi E Initial condbons &£]3|X|^j^!o< Forward and inverse modekng 3" <9 i "~> & A1 1C I Printing and numerical method <*> ^0 ifi iH V* ^ Stofchonetry and thermodynan*: data S? &" >fl X° 3? 3 a - 0 Inputffes * - 1) «1pq fc TITLE Example 1 -Add uanun and special units ppm pH 8.22 pe 8451 denslii 1.023 - temp 250 redo* 0|0|/0(-2] Ca 412.3 Mg 1231 8 Na 107680 K 3931 Fe 0002 Mn 00002 pe - 0 19353.0 - AkaWy 141.682asHC03 S[6) 2712.0 N|5) 029 gfw E20 N(-3| 003 as NH4 9 lnPK 1 "® Enns/Wanings | leody mm TITLE Example 1. Add ui SOLUTION 1 SEAVATER FR< pH 6.22 PE 6.451 density 1.023 temp 25. 0 redo* O(0)/O(- Ca MB Na En Si Cl Indrvidual element nput | (jotopes (Advanced] | urits: |ppm 3 Select etanentt/redox stales Select napis | Select Jace Ehaigebalance: |(none) ^] | Customselect | Modify custom... OAI DC fe,CI 6SFe DU iJN yiNa DHS- i HAkaWy DC03-2 DCu BFet2 sSMg DN2 S502 fS04-2 I 3fl DCH4 DCut BFetS .gMn DN02- DP ESi t Gfla ijCa DCut2 DH2 »Mm2 ^NH4* DPb DSr C DBi DCd DF S3K BMm3 .^N03- BS 0U «l 1 H i 2 3 4 5 6 Eleaent Ca Mg No K Fe Mn Cone. 4123 12918 107S8 3991 0002 00002 [Unfts] (Oetaut) [Defaull [Defaul) [Defaut] (DefaJt) Pefau») [Phatel [S.I.] [At/GFW] Descijptan of mput Element 1st - An element name a a kst of element valence stales separated t* white K element names and valence states must correspond to the items in the fist column in SOLUTION_MASTER_SPECIES. Alkalinity 3(6) Nl-3) 0.03 n 3.3 0(0) 1.0 SOLUTION BISTER SPECIES D 0+4 0 . 0 D(4) D+4 0.0 D(5) DO2+ 0.0 0(6) DO2+2 0.0 |j BR as HR4 ppb H(5)/N(-3) O2 (o) -0.7 236.0290 236.0290 238.0290 236.0290 236.0290 IRedcKl P« pace. The fl ^Cancel | Help | ' NUM Figure 1. Main screen of PHREEQC!, with the SOLUTION keyword dialog box open. U.S. Department of the Interior U.S. Geological Survey USGS Fact Sheet FS-031-02 April 2002