Paint Contamination in Containment

Q. What is the best way to deal with leaked paint froman electrocoat system that ends up in containment, from an environmental, economic and safety point of view? 1) Treat it in wastewater, 2) have it pumped out and disposed of as hazardous waste, 3) filter through bag filters and return to the paint tank, or 4) another option. T.F.

A. To determine the best alternative from all standpoints, first pump the leaked paint out into a holding tank and have the electrocoat supplier take a sample for lab testing (percent solids, conductivity, pH, etc.). Also, ask your supplier to perform several panel coat-outs at different voltages and to mix ratios of raw electrocoat to recovered and filtered electrocoat. This will determine the chemical condition, visual deposition quality and overall suitability of the electrocoat paint.

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Most of the time, depending on the level of dirt and oil contamination in the containment area, the paint can be filtered through normal bag and oil filters until no fish eyes or craters are found on the panels. After the visual quality is acceptable, the paint can be fed back into the tank a little at the time until complete recovery is accomplished. The feed rate would be calculated based on the lab studies performed by your electrocoat supplier. This is always a critical decision after complete recovery of a large spill; typically, the slower the better.

If the electrocoat paint is contaminated beyond repair and is deemed unacceptable and unusable, it is best to dispose of it instead of treating it in your own waste treatment system. Typical waste treatment systems are not designed to treat organic waste. Because current electrocoat technologies do not use heavy metals and have very little solvent, and this solvent is not considered flammable or combustible, the electrocoat paint usually can be disposed of as general industrial waste and not as hazardous waste. If the paint contains some metals or significant amounts of solvent, it should be incinerated as hazardous waste.

In my experience running e-coat systems, I always was able to recover spilled electrocoat paint after intensive filtering through bag and oil filters. Typically within one week the paint was ready to be fed back into the bath.