Carbon Disulfide Contaminated Sludge Disposal

[sta07750]

My employer has recently emptied a 500,000 gallon tank that was full of water contaminated with Carbon Disulfide (CS2) and other organics. It was pumped down and run through carbon beds to remove the contaminants. Now at the bottom of that tank we have about 6 inches of sludge (roughly 6000 gallons) that is contaminated with visible amounts of CS2 and water. CS2 is quite volatile, flammable, etc. The original plan of attack was to suck the sludge out with a vac truck and let an environmental company handle the disposal. Now concerns have been raised that it's too dangerous to let someone enter this confined space to push the sludge to the vac truck and that any CS2 vapors that make it into the vac system will be ignited by the heat source that is the compressor/pump on the vac truck (the autoignition temp of CS2 is about 195 F). We considered interting the tank with N2 so we are under the LEL but that doesn't make us feel all that much more safe and if there is an N2 blanket we can't have someone enter the tank to push the sludge to the vac hose so that doesn't help either (our confined space permits require 19-23% O2). We considered using steam to drive the CS2 off but it would take quite a bit of doing to drag a steam line out to where this tank is and we'd run the risk of autoignition anyway.

Does anyone have any experience working with CS2 disposal or anything that might be relevant? Thanks.

 

[bimr]

Would suggest talking to the technical expert of your chemical supplier.

Common spill cleanup methods for carbon disulfide are to mix with agricultural lime and water.

 

[sta07750]

Would you happen to know the reaction taking place with the calcium carbonate and water?

 

[bimr]

CS2 + 3Ca(OH)2 >> CaCO3 + CaCS3 + H2O

It reacts to produce calcium thiocarbonate.