Tuesday, November 29, 2005
IN CASE YOU WONDERED
YOU MIGHT HAVE READ Russia and China are bringing in "chemicals" to help treat the chemical spill in the Songhua River. The "chemicals" are activated carbon.
Explainer over at Slate does a pretty good job explaining what activated carbon is and what it does:
http://www.slate.com/id/2131130/?nav=tap3
One thing Slate omits is the fate of the carbon itself once its spent - once it has adsorbed all the organic pollutants it can. Details may vary in Russia or China, but here in the US, depending on the nature and volume of the adsorbed contaminants, spent carbon would be:
1) Landfilled in a hazardous waste approved landfill if the contamination was minor - not an option in this case.
2) Mixed with waste paint, solvent, or oil and used for "A" fuel - "A" for alternate - at an approved facility like a cement kiln. This would be most likely in the case of benzene.
3) Finally, if the contaminants were really nasty - DDT or Pentachlorophenol, for example - it would go to an incinerator where full destruction via high-temperature, high oxygen combustion would be assured.
While it is possible to recycle activated carbon, the cost is great enough it's cheaper to destroy it and make more.
Explainer over at Slate does a pretty good job explaining what activated carbon is and what it does:
http://www.slate.com/id/2131130/?nav=tap3
One thing Slate omits is the fate of the carbon itself once its spent - once it has adsorbed all the organic pollutants it can. Details may vary in Russia or China, but here in the US, depending on the nature and volume of the adsorbed contaminants, spent carbon would be:
1) Landfilled in a hazardous waste approved landfill if the contamination was minor - not an option in this case.
2) Mixed with waste paint, solvent, or oil and used for "A" fuel - "A" for alternate - at an approved facility like a cement kiln. This would be most likely in the case of benzene.
3) Finally, if the contaminants were really nasty - DDT or Pentachlorophenol, for example - it would go to an incinerator where full destruction via high-temperature, high oxygen combustion would be assured.
While it is possible to recycle activated carbon, the cost is great enough it's cheaper to destroy it and make more.
