Heavy metal in wastewater

[refiner]

Hi.
I wonder if activated sludge system can handle heavy metal.especially arsenic and mercury, in wastewater or not. Concentration is 150 mg/l As, 0.1 mg/l Hg, and COD of 2500 mg/l. Or is there any pre-treatment system that can handle before sending to the activated sludge.
Thank you in advance for any suggestion.

 

[kenvlach]

Can an activated sludge system can handle heavy metal?
--Only if it includes nuclear fission or fusion to transmute the heavy metal to something non-hazardous, e.g., light metal.

It is imperative that heavy metal wastes be segregated and treated separately from organics to avoid it all becoming permanently hazardous. And, note that mercury reacts with organics to form the more toxic methyl mercury.

 

[luissabate]

It's better to remove heavy metals first.
- no inhibibition to bacteria
- less sludge with heavy metals (has to be treated)
- more efficient metal removal.

 

[Peteypete]

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 oxide. The mercury treatment is easier, and a good resin for this is available. You have not mentioned discharge objectives, but the Hg discharge can reach sub 1.0 ppb consistently at 100 M3/hr (~40 gpm).

If you are interested in this, you can contact me at pmorton@ecsrefining.com