Hossein;

Zeolite is one of the more popular adsorbents. 

Please see link below. Hope it helps. 

http://www.mla.vgtu.lt/index.php/mla/article/viewFile/808/pdf

Steve

Hossein, from your question it is not clear if the wastewater to be treated is polluted with formaldehyde only. In that case the adsorption is good choice. In case that there are other pollutants, the biological treatment could be much easier. In such a low concentrations the formaldehyde is easily biologically degradable.

best regards

Vit

Thank u for your good respond. But i have an urban wastewater which after biological treatment by anaerobic method, in the effluent we have 1.5 ppm formaldehyde. Hence, we must remvove it to lower than 0.5 ppm according to the standard conditions of water.

So, i am searching a powerful bioadsorbent which it be cheap and effective. I am working on the activated carbon for its removing. The activated carbon is prepared from Lotus leaves. 

I am thank some one that introduce some good bioadsorbents for this purpose.

Regards

What is the quality of treated wastewater after anaerobic step. What is the COD and BOD5 or BOD3, concentration of suspended solids, pH? The amount to be treated?

Dear Mr. Hossein Esmaeili , you can try activated carbon for the adsorptive removal of formaldehyde.

Hi Mr. Esmaeili,

Did you try additional retention time in aeration? As I know, formaldehyde is a volatile compound and also high temperature allow more vaporization of formaldehyde. However you should consider cost of additional aeration and heating with adsorption cost.

Good afternoon

If you use activated carbon, how can I calculate the life time of the carbon?

 I dont know how can calculate the life time of the carbon!

I don't know about effectivity of prepared from Lotus leaves activated carbon, but activated carbon from birch wood is good in formaldehyde removal.

Dear marta 

Are you sure activated carbon prepared with birch wood is proper to remove formaldehyde from waste water?

If you have paper about it, please send me.

Thanks

I don't have paper about it. Some years ago I did some adsorption experiments with organic pollutants. But it was experiments with model water, not with waste water.

Adsorption on zeolite, activated carbon, activated alumina, sodium sulphite, Fenton’s

process, photo-Fenton’s process, electro-Fenton’s process, ozonation with the addition of H2O2, catalytic ozonation, and H2O2/UV process may be used to treat formaldehyde from waste water. The following paper has activated Carbon and alumina as adsorbent.

http://www.cwejournal.org/abstract/vol6no1/adsorption-of-formaldehyde-on-treated-activated-carbon-and-activated-alumina/

As the concentration of formaldehyde is relatively low, adsorption by activated carbon using  powdered type will be one of the appropriate methods you can adopt.

How can I know when change the carbon? There is way in order to calculate the capacity of carbon?

thanks from my dear friend.

Your information is very useful to me.

Best wishes for all.