CO2 - Can it be useful in a Wastewater treatment plant

[JasonMoore]

Is there any place in conventional wasterwater treatment where the addition of CO2 could help the proceess? Is there a place where it would alter its composition rather than just off gassing?

 

[TerraSouth]

Good question!

One problem encountered in on-site wastewater is nitrate reduction. Denitrification is an aerobic process, and the problem with getting the anaerobic bacteria to complete the process is a lack of carbon. Activated sludge processes are very good at nitrification, but very poor at denitrification. Most engineers try and return the effluent from the activated sludge back to an anaerobic tank to try and get some denitrification before disposal but the problem is always a lack of carbon. Could CO2 be introduced at this point as a carbon source to get better denitrification??

I don't know.. Maybe someone here does?

I have often thought that maybe I could design a large tablet made out of CACO3 that could be inserted into the final anaerobic process that would give the bacteria the carbon they need, and in the process get the nitrate level down.

Interesting! Any other input?

 

[kchayfie]

We once looked at adding methanol to provide the carbon source. As far as I remember, the chemical costs were looking prohibitively expensive but then the money men in our company pulled out of the project and we never got chance to reach a final solution.

 

[munich]

JasonMoore
Check the solubility of CO2 in water. If I remember right it's low. TerraSouth is perfectly right with his hint towards de-nitrification, however CO2 and its solubility may be the limiting factor.
Cheers
munich

 

[bimr]

CO2 is already being used for pH control purposes. However, it has to be carefully dissolved into the water to avoid off gassing. Other acis are preferred over CO2 because they are more economical.

You would also have to liquify the CO2 to transport it to the treatment plant.

 

[JasonMoore]

Thanks for the responses, the CO2 will already be on site as it is a byproduct of another process. We just want to see if there is an application for it before we look at destruction or abatement

 

[bimr]

Well, if you have a hugh volume, you can liquify it and sell it.