PHREEQC

["Doug Ilett" <doug.ilett@xxxxxxxxxx>]

Dear David,

RE: PHREEQC data requirements

I wonder if you could help me with the following query regarding the format of data for the PHREEQC code ?

I currently manage the HATCHES database - a thermodynamic database for groundwater modelling which is distributed via the NEA in Paris, France.  The data is currently output in a form suitable for use with the PHREEQE and EQ3/6 codes.  I am looking at the feasilbility of distributing the data in a form suitable for use with PHREEQC.

The query I have regards the equations of formation for the aqueous species. In the HATCHES database these are all written in the form suitable for PHREEQE i.e. always from the "master species".  As I understand it, PHREEQC requires the equations to be specified in terms of a particular oxidation state, in order for the different oxidation states of redox sensitive elements to be distinguished e.g. Fe+2 species should be written in terms of Fe+2, Fe+3 species are written in terms of Fe+3 etc.  If this is not done and, say, Fe+3 species are written in terms of Fe+2, the species is assumed to be Fe(II).

For use with PHREEQC, would it be necessary to rewrite the equations for all aqueous species containing redox sensitive elements ? (or have I got this wrong ?!!)

Thanks for any help,

Best Regards

Doug Ilett
AEA Technology plc
Harwell
UK    +44 (0)1235 433225




***********************************************************************
This transmission contains information which may be confidential and  
which may also be privileged.  It is intended for the named addressee  
only.  Unless you are the named addressee, or authorised to receive it 
on behalf of the addressee you may not copy or use it, or disclose it 
to anyone else.  If you have received this transmission in error please 
contact the sender.  Thank you for your cooperation. 
***********************************************************************

For more information about AEA Technology please visit our website at http://www.aeat.co.uk

AEA Technology plc registered office 329 Harwell, Didcot, Oxfordshire OX11 0QJ.
Registered in England and Wales, number 3095862.