Disposal of cutting fluid

[naytep]

What is the proper way to get rid of used cutting fluids? Until now I have been dumping them at the DOT center in my city. This is a good place to get rid of the tramp oil, but the cutting fluid isnt exactly oil.

[Geof]

We have to pay a licensed recycler to come and get our tramp oil and coolant waste so we separate and concentrate it first. The charge for tramp oil mixed with water is higher than just oil and the charge for coolant depends on the volume of course.

Waste coolant from the machines goes into a 50 gallon drum equipped with a skimmer.

At the bottom of this drum the coolant is pretty much free of oil so we take this out through a dip tube into another drum which is heated and stirred so the water evaporates. It takes about ten days to reduce the volume by around 75% by which time the evaporation rate is so slow it is not worth waiting longer. This concentrate then goes to the recycler.

The tramp oil from the first skimming has some coolant in it so this is skimmed a second time and the coolant from the bottom of the second skimming tank goes into the evaporator drum.

The tramp oil from the second skimming is pretty much free of water and coolant so this goes to the recycler as 'clean' waste oil.

All this is set up in a little shed outside the shop because it smells a bit.