Ask the Expert Question-and-Answer Archive (Wastewater Treatment)

by Mike McGinness, EcoShield Environmental Systems, Inc.
February, 2002

Paint Manufacture and its Pollutants

Q. I need to know about the paint manufacturing process and the pollutants (specificially water) that are produced and how these pollutants are treated/processed before they are discharged into the environment. Any online resources that you can provide me would be of great help.

Thank you.

A. Thanks for your Question. Checking CFR-40 Clean Water Act Categorical Pretreatment limit categories I only found one listing for oil based paints that seems to have a zero discharge total prohibition against any waste water discharge associated with manufacturing oil based paints. This leads to the questions of what is the definition of "Oil", "Paint" and "Manufacturing" in my opinion. A number of years ago I researched the definition of "OIL" and found an a single definition buried in another CFR category that defined "Oil" as any crude oil derived substance from fractionation or distillation processes. This would not include synthetic organic chemicals or solvents. Paint of course could have a very wide definition. The manufacturing I suspect would be primarily blenders, formulators and possibly some synthetic paint ingredient manufacturing steps especially if they are under the same roof as the paint blending and formulating operations. It could get very confusing and complicated at this stage. Based on what I found so far I am not sure if a water based latex paint would be included in this prohibition, but as long as the paint formula did not include "Oil" as defined above then it appears that non-oil based paint manufacturing does not have a categorical pretreatment limit.

In cases where there is not a categorical pretreatment limit there are still other federal, state and city limits and requirements which still must be meet for discharges. One general federal requirement is for pretreatment programs and limits for "Significant Industrial Users" which is defined as any discharger that contributes 1 or more percent of the flow to the head works of a POTW (Publicly Owned Treatment Works), or a discharger who has the potential to discharge sufficient quantities of any substance that could interfere with the normal operation of the POTW waste water treatment system.

The site for the Oil based paint categorical limit is attached below. The URL is: http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr446_03.html.