Disparities in BTC comparing PHREEQC with HP1

The HP1 code incorporates modules simulating
(1) transient water flow in variably-saturated media,
(2) transport of multiple components, and
(3) mixed equilibrium/kinetic geochemical reactions.
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Itza
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Joined: Sat May 01, 2010 6:14 pm
Location: USA
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Disparities in BTC comparing PHREEQC with HP1

Post by Itza » Thu May 13, 2010 4:30 pm

Hi
I compared HP1 with PHREEQC for numerical simulations of nonlinear degradation of ammonium via nitrification with Oxygen and Ammonium limitation. The reaction occurs during steady state water flow. Ammonium is defined as a new species (Ammonium) and Oxygen is used as defined by PHREEQC. The PHREEQC code used in both PHREEQC and HP1 for the reaction is as follow:
RATES
Amm_to_nit
-start
10 if (m <= 0) then goto 200
20 mO2 = mol("O2")
30 rate1= mol("Ammonium+")/(parm(1) + mol("Ammonium+"))
40 rate2= mO2/( parm(2) + mO2)
50 moles = -parm(3)*rate1*rate2*TIME
60 if (moles > m) then moles = m
200 save moles
-end
KINETICS 1-161 @Layer 1@
Amm_to_nit
-formula Ammonium 1 O 2
-parms 1.9e-4 1.7e-5 1.73e-2

When only advection dispersion is simulated PHREEQC and HP1 give the same result for Ammonium and Oxygen. However, when Advection Dispersion Reaction is modeled, PHREEQC result shows that oxygen is consumed, while in HP1 oxygen decreases up to a close to zero limit followed by an increment.

What could be error if I was expecting to see Oxygen consumption up to zero just like the result from PHREEQC?

I would like to paste a figure of the breakthrough curve but I don't know how. Could you explain me how?

THANKS

diederik
Posts: 51
Joined: Fri Mar 10, 2006 7:57 am
Location: Belgium

Post by diederik » Fri May 14, 2010 4:01 pm

Hallo,

can you send me the HP1 project by email (djacques@sckcen.be

thanks,
diederik

Itza
Posts: 3
Joined: Sat May 01, 2010 6:14 pm
Location: USA
Contact:

Post by Itza » Fri May 14, 2010 9:42 pm

I already sent it
THANKS

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