Chad,
Sorry to get back to you so late - I was on vacation for the summer.
I looked at our data for the reaction and found that we used a strong acid resin from Sybron. I am not sure which one it was as we were able to use old virgin product that was discarded. I am not sure about treated...
We have looked this phenomenon and it appears to be carbon dioxide degassing. You can accelerate the degassing by using warm water (15-30 minutes @60°C) or an alcohol like methanol (as a wetting agent). You can inhibit the degassing by placing the anthracite in "carbonated water."
Seidelc is correct in the treatment of Cr6. I can confirm his reported reduction of Cr6 with FeSO4. We did this in acid resin (the acid helps with the reaction). Once Cr+3 is formed, then the acid resin adsorbs it. We also added H2SO4 to the solution of FeSO4 to help with the Cr6 reduction...
There is a resin that may work for you depending on the feed metal concentrations and the level of reduction desired. The nickel reduction has reached 99.4% (depending on the feed concentration).
You can contact me at pmorton@ecsrefining.com. If you send me the concentration data with...
There is no question that, in general, you should treat the metals first before going to a activated sludge tank.
To treat the metals, the system would be divided into two separate resin units: one for As, and one for Hg. Arsenic treatment can be tricky, but standard systems use supported iron...
The best technology I know of for low metal concentrations is resin/solid adsorbents. You can use GAC before the resin bed to help with fouling and that GAC also will adsorb some Hg.
Great resins are few, but there are some new ones. Romic Chemical in East Palo Alto, CA is using a resin to...