Solvent recycling and safe disposal of sludge

[blue.magic]

How do you recycle your solvents and dispose the waste from distillation?

I have collected quite a lot of used solvents (acetone, DCM, heptane, MEK, naphtha, toluene) and it's time to recycle them.

Would you filter the solvents before distillation? Or perform any other work up steps?

What would you do with the waste? It will mostly be plant fats, alkaloids and whatever came through the extractions.

Landfill is one option though this not eco friendly.
Evaporation of the solvent sludge is another option but dangerous and not eco friendly.

Chem suppliers offer safe disposal (they recycle the solvents in a factory) but this can lead to suspicion.

Yet another option is a waste collection center where they accept mostly household and industrial chemicals as "dangerous waste". Maybe it would be best to collect sludge from the respective solvents and then leave it there.

Maybe it's also possible to react the sludge somehow to make it safer for disposal?

 

[downwardsfromzero]

I'd do a final acid wash to pull any remaining alkaloids from water-immiscible solvents. Anything not being recovered by distillation - except DCM - I would just burn by soaking into paper and using as a fire-lighter when required.

Distillation residue I would treat similarly if I was certain there was no chlorinated component. Mop it up on a paper towel, add a bit of acetone and burn it.

DCM is kinda precious so I'd keep on recycling that until it's all disappeared.

Otherwise just put it all in an old paint tin and take it to the household waste disposal. All those solvents can be found in various paint-type products anyhow.

 

[Ulim]

Burn them.

For DCM or Chloroform a reaction with Fentons reagent will destroy them.

 

[blue.magic]

Burn them.

For DCM or Chloroform a reaction with Fentons reagent will destroy them.

Thanks. I was concerned about the chlorinated solvents as I have little experience with them (I use DCM for defatting and chloroform maybe in later extractions / simple syntheses).