Re: Release of PHREEQC 2.7 and PhreeqcI 2.7.0.1

[peter.schipper@xxxxxxxxxxx]

David,

Last week I asked you this question:
> Are there developments to make PHREEQC suitable to simulate the transport
of DOM in groundwater?

thanks for your replay,
> You can add a new constituent "Dom" and have it react through REACTION,
> KINETICS, SOLUTION_SPECIES. The wateq4f.dat already has a minimal
> definition of  "Fulvate" and "Humate". But I think you want more than this.

But I still have an question:
I want to model 1-D transport (along a flowpath) and simulate kinetic or equilibrium redox-reactions with "dom", just as I 'm used to do with organic matter or pyrite. Now I want to let "dom" reduce Fe(OH)3 consistents in the sediment (see reaction 5-7 where CH2O = "dom" ):
[5]        4Fe(OH)3(s) + 12H+ + 4e-  4Fe2+ + 12H2O
[6]        CH2O(aq) + 2H2O   4e- + 5H+ + HCO3- 
[7]        4Fe(OH)3(s) + CH2O(aq)  + 7H+  4Fe2+ + 10H2O + HCO3-

Can I do this with reaction - kinetics - solution_species?

yours sincerely
Peter Schipper

"David L Parkhurst" <dlpark@xxxxxxxx> 21-02-2003 15:49

To:        peter.schipper@xxxxxxxxxxx         cc:                 Subject:        Re: Release of PHREEQC 2.7 and PhreeqcI 2.7.0.1

> The last 3 years, I have used PHREEQC (and phast) for several problems
with groundwaterquality in the Netherlands. However, in most of these
problems dissolved organic matter (DOM) is an important ( key)factor for
the observed patterns. F.i. the mobilsation of ferro and arsenic in areas
where the long past seapage is changed into infiltration near the
exfltration for a drinkwatersupply, or the transport of metals like zinc
and cupper through soils with high DOM-content.

> Are there developments to make PHREEQC suitable to simulate the transport
of DOM in groundwater?

You can add a new constituent "Dom" and have it react through REACTION,
KINETICS, SOLUTION_SPECIES. The wateq4f.dat already has a minimal
definition of  "Fulvate" and "Humate". But I think you want more than this.

> And if so, also options to implement a module for competitive (not
linear) binding of ions to DOM, like tipping-VI?

I don't have any immediate plans for implementing metal-organic binding in
PHREEQC. It's on my list of things to do, but not very high on it. You may
want to contact Tony Appelo. At one point he had made a database that
implemented Tipping-like metal binding by special definitions of
SOLUTION_SPECIES.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled