Ask the Expert Question-and-Answer Archive (Wastewater Treatment)
by Mike McGinness, EcoShield Environmental Systems, Inc.
October, 2002F19 Sludge From a Coil Coating Process
Q. Would a sludge from a wastewater stream from a coil coating process where a conversion coating was applied to aluminized carbon steel be a F019 hazardous waste stream, or does the fact that the coating is applied to aluminzed steel and not aluminum let it escape this waste designation ? If you know of any references that support or refute this argument Id be most grateful.
A. I have had similar questions come up in the past. In my opinion this one of those not so clear, gray areas.
My inclination is to look at the conversion coating formula ingredients as well as the substrate to help make the final determination. The safe answer is yes the EPA could call it a listed hazardous waste, however, if you look up the F019 details and the F006 details (which is the other code possibility since the term conversion coating is used in the definition of the electroplating category) you will find the following:
F019: Wastewater treatment (T) sludges from the chemical conversion coating of aluminum except from zirconium phosphating in aluminum can washing when such phosphating is an exclusive conversion coating process.
F006: Wastewater treatment (T) sludges from electroplating operations except from the following processes: (1) Sulfuric acid anodizing of aluminum; (2) tin plating on carbon steel; (3) zinc plating (segregated basis) on carbon steel; (4) aluminum or zinc-aluminum plating on carbon steel; (5) cleaning/stripping associated with tin, zinc and aluminum plating on carbon steel; and (6) chemical etching and milling of aluminum.
Both code numbers list exceptions. Finally if you look up Appendix VII to Part 261 Basis for Listing Hazardous Waste you will find cadmium, hexavalent chromium, nickel, and cyanide (complexed), listed for F006, and hexavalent chromium, and cyanide (complexed) only, are listed as the compounds used as the basis for listing these as "Listed Hazardous Wastes."
Of course you must still verify that the sludge is not characteristically hazardous before making a final determination. Considering the new directions EPA has taken in recent years to implement new programs such as the Common Sense Initiative, the new Universal Waste Rules, promotion of Environmental Management Systems and sustainable economics and the fact that the industry standard formula ingredients for conversion coatings has been moving away these ingredients (i.e. iron phosphate is sometimes called a conversion coating, but is also sold as a biodegradable water soluble cleaner and pre-paint metal prep for steel and typically does not contain cadmium, chromium, nickel or cyanide) I would suggest looking at the actual ingredients used in the application you are asking about.
If the hazardous waste metals are present in the make up solution as received in significant measurable quantities (beyond trace concentrations, i.e. say greater than 1 to 10 ppm, depending on the dilution concentration in the operating bath), or show up as TCLP leachable metals in a sludge leach test, I would suggest using one or both codes as the hazardous waste designation. If the metals are not present in either situation above, then you have 2 options. Option one is take a position that it is not hazardous waste (but that does not mean it is not a regulated waste), which may be a little risky but if the HW metals are below detection limits in a Total Metals analysis of the sludge (versus TCLP tests) I would be inclined to consider it a non-hazardous waste and do one of the following.
Now lets assume for the sake of argument that several Total Metals tests did not detect the HW metals. The only remaining concern is that they are calling the process a conversion coating. I was told recently that what a facility called it (under similar circumstances) was the deciding factor in a court case where the EPA considered it a listed hazardous waste and the facility lost the argument in court because their literature called it a conversion coating (it was an iron phosphate solution that is sold is a cleaning solution and a conversion coating, where it is the same exact formula sold under 2 different labels). Then I would ask if they (the supplier and the user) could call it something else, or I would apply to the EPA to have that specific facilities waste sludge formally delisted in 40 CFR.
