EHS Q&A: Waste Treatment for Paint Stripping
Q. We will be using concentrated sulfuric acid to strip e-coatings from reject metal parts ... Unfortunately, our only outlet for discharge of this waste is to a nearby storm drain, and we know that we will need to remove the paint sludge and color and to neutralize the pH before discharge. Can you advise?
Stephen R. Schulte
P.E. REM, Hixson Inc.
Q. We will be using concentrated sulfuric acid to strip e-coatings from reject metal parts. The parts will be immersed into the acid solution, and the stripped coating will migrate into that solution. After a day, the acid will be spent because it is full of paint sludge, and we will need to replace it with new acid. Unfortunately, our only outlet for discharge of this waste is to a nearby storm drain, and we know that we will need to remove the paint sludge and color and to neutralize the pH before discharge. Can you advise? T.T.
A. You present a very challenging problem. I will give you my thoughts, and I invite our readers to submit their suggestions as well.
First, I urge you to look into disposing of this waste material as a hazardous waste, either in 55-gal drums or by collecting and storing in a bulk tank and disposing via bulk tanker truck, depending upon the volume. If you decide to store this corrosive hazardous waste in a bulk tank, the tank system needs to comply with U.S. EPA hazardous waste regulations under 40CFR262, Subpart C, and 40CFR265, Subpart J (with a few exceptions), as well as your state’s regulations. (Go to epa.gov/waste/inforesources/pubs/training/tanks05.pdf for further guidance.) As you will see below, treating this waste material will be extremely challenging and costly, and highly regulatory.
Because you propose to discharge to a storm drain that is connected to surface water, you will be required to apply and obtain a direct discharge permit (aka NPDES permit) either from your state or from your U.S. EPA region if your state does not have an approved NPDES program.
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