Are there papers which writes about differences in phreeqc, wateq4f and minteq (or minteqv4) thermodynamics databases and which of these is preferable?
...for databases see http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/html/final-90.htmlyesee and for a coupled model (i.e. hydrus and PHREEQC) see http://www.pc-progress.com/en/Default.aspx?h1d-hp1. Best Nils
HYDRUS will run PHREEQC
http://www.pc-progress.com/en/Default.aspx?h3d2-HP2
There is another one called PHT3D. It incorporates MT3DMS for the simulation of three-dimensional advective-dispersive multi-component transport and the geochemical model PHREEQC-2 for the quantification of reactive processes. PHT3D uses PHREEQC-2 database files to define equilibrium and kinetic (e.g., biodegradation) reactions.
http://www.pht3d.org/
Panagioti:
There is also PHAST which couples the USGS 3D flow/transport model HST3D with PHREEQC and has a very nice user interface which makes it easy to set up the model domain and spatially varying initial conditions.
As far as which database is preferable, it really depends on the problem and objectives. wateq4f.dat was developoed by USGS and includes data for the most important major and trace species and phases in natural water systems. phreeqc.dat is essentially a subset of wateq4f with fewer trace elements. minteq.dat was developed by USEPA and includes more extensive coverage of trace metals, metal-organic complexes and species that are related to hazardous wastes (minteq.v4 is an updated version). If you are modeling high ionic strength waters (I>1), then pitzer.dat may be more appropriate although it may not include data for all the elements in the other databases. Most important is to check the literature for more recent thermodynamic data for the elements you are modeling and compare to what is in the default databases as these were developed some time ago and are not updated frequently.
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I have extensively used integrated hydrological models and to be honest (combining/integrating) two different models is very challenging.
The more recent extension of the original single-species transport code MT3D to the multispecies transport simulator MT3DMS provided the starting point for the development of a number of models that simulate coupled hydrological transport of multiple chemical species and the chemical reactions among these species. For example, RT3D couples the implicit ordinary differential equation (ODE) solver LSODA to solve arbitrary kinetic reaction problems. RT3D provides a number of pre-defined reaction packages, e.g., for biodegradation of oxidisable contaminants consuming one or multiple electron acceptors and for sequential decay chain-type reactions of chlorinated hydrocarbons (CHCs). The BIOREDOX model , SEAM3D and MT3D99 (1999) also simulate the fate of specific pollutants, i.e., BTEX and CHCs by solving purely kinetic biodegradation reactions. On the other hand, GMT3D, a model that addresses a whole range of reactive processes such as aqueous complexation, mineral dissolution/precipitation and surface complexation reactions by coupling the geochemical package MODPHRQ to MT3DMS. In contrast to the previous, so-called ‘multi-species’ models, the transport equation is not solved separately for each chemical species but for total aqueous component concentrations . However, all reactions included are treated as equilibrium reactions, limiting the generality of the approach. Therefore, in my experience calibration and validation and co-relation of the combined model is very difficult.
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