Foam In Cooling Tower

[MedicineEng]

Dear All:
I have a problem in one cooling tower that I would like to seek your help.
The issue is the following:
Last Summer we installed a new ammonia brine chiller and we dedicated to it a cooling tower for the refrigeration water. Right now we are facing a problem that is this cooling tower is creating some foam. At the beginning we tought that this foaming was the reaction of bacteria and algae to the biocide of water from utility company. But when I tested the water for chlorine content, I noticed that the value was nearly indetectable. After that, and since we were convinced that this was the main cause, we gave a treatment shock to the cooling tower by adding biocide up to a level of 1.5/2.0ppm. This created a lot of foam as expected. My problem is that after this treatment it seems that theres in no improvement and the foam continues to appear. Do you think that we need another shock treatment? I think that maybe there are other reasons for this since the other cooling towers are not experiencing this situation.
I am suspecting that there might be other reasons:
-Lately, the water salinity has been increasing since we are in the dry season and this year has been particularly dry and the salinity levels are quite high;
-This cooling tower only feeds the chiller that is in the level below and returns back at a flow that is higher than the design;
-The temperature of this cooling tower is usually higher (3/5C) than the others.

This is just my crazing thinking but can it be that the high flow of the water together with the increased salinity creates a water "foamification" phenomenon? What do you think?
Thanks a lot and sorry for the long post.

 

[toothless]

I'd just add a few drops of anti-foam treating agent and not worry about it unless some other problem arises. Anti-foam is available through your water treatment supplier, and a little bit goes a long way.