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Trouble in modeling NO3 in a wastewater pond

Fatemeh GholamiMahyari, modified 1 Year ago.

Trouble in modeling NO3 in a wastewater pond

Youngling Posts: 23 Join Date: 4/8/16 Recent Posts
Hi Everyone

Before telling my Problem I should thank WAQ group which has helped me a lot so far. I am working on modelling a wastewater stabilization pond. I have modeled the pond most of model results including DO, PO4 and biomass seem so good but NO3. Nitrate modeled are too high comparing to observed data. Actually algae in the pond increased NO3 instead of absorbing it. I changed many parameters related in absorbing NO3 by algae but any of them had not affect on NO3 modelling. I was wondering could somebody help me and give me some advice?

Regards,
Fatemeh
Michelle Jeuken, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts
Hi Fatemeh,

Your welcome! Have you looked into other limiting factors? When algae growth is limited by phosphorus or light, changing anything in the nitrogen doesn't affect the result.

Michelle
Fatemeh GholamiMahyari, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Youngling Posts: 23 Join Date: 4/8/16 Recent Posts
Dear Michelle

Thanks for your quick respond. I changed many factors such as N/C in Algal stoichiometry section as well as mortality rate and fraction detritus. None of these changes helped me. I was gonna do some changes about a parameter (fam) which you mentioned in the D-Water_Quality_Processes_Technical_Reference_Manual, but I could not find it in the process parameter. If you help me to find out what is it, that may solve y problem. In D-Water_Quality_Processes_Technical_Reference_Manual there is a parameter f am in the page 89&90, which is defined as "fam fraction of ammonium in the consumed nitrogen nutrients". How can I change this parameter? If you have any suggestion please tell me. I would appreciate your help.

Thanks
Fateme
Michelle Jeuken, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts
Hi Fateme,

Both the BLOOM and DYNAMO algae models have a preference for NH4. The only will take NO3 when there is hardly any NH4 left.

For BLOOM algae, you might change ThrAlgNH4, for DYNAMO algae, it is possible rise NH4KRIT, to increase the preference for NO3. If you can't find them in the PLCT, you might also add them to the sub-file manually. Just copy an other parameter in the file, and change the name.

The fraction NH4 is then an output: FracUptNH4. When there is enough NH4, it will be 1.0.

greetings,
Michelle
Fatemeh GholamiMahyari, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Youngling Posts: 23 Join Date: 4/8/16 Recent Posts
Thanks a lot dear Michelle

I will do as you tell me and tell you the result.

Regards,
Fateme
Fatemeh GholamiMahyari, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Youngling Posts: 23 Join Date: 4/8/16 Recent Posts
Dear Michelle

Thanks a lot. I did as you tole me and my problem with NO3 has solved. I am so grateful to you and your group.

Regrds,
Fateme
Michelle Jeuken, modified 1 Year ago.

RE: Trouble in modeling NO3 in a wastewater pond

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts
And thank you for letting us know!

Michelle