1994(01)

HOTLINE QUESTIONS AND ANSWERS

December 1994

2. Elementary Neutralization Units Generating and Storing Non-Corrosive Hazardous Wastes

The operator of an electroplating facility neutralizes corrosive D002 wastewaters with lime in an on-site tank. The neutralization process causes a sludge to accumulate at the bottom of the tank. Although it does not exhibit the characteristic of corrosivity, this sludge from the treatment of electroplating wastewaters meets the definition of FOO6 listed hazardous waste (40 CFR 261.31). The neutralization process thus causes a non-corrosive hazardous waste to be generated and stored in the treatment tank. Can this tank meet the definition of an elementary neutralization unit?

This treatment tank at the electroplating facility meets the definition of an elementary neutralization unit, because the waste originally treated in the tank is hazardous only due to corrosivity. According to 40 CFR 260.10, an elementary neutralization unit is a device which: (1) is used for neutralizing wastes that are hazardous only because they exhibit the corrosivity characteristic, or are listed only because of corrosivity; and (2) meets the definition of a tank, container, transport vehicle, or vessel. As long as the original influent waste is hazardous only due to corrositivity, generation of a new, non-corrosive listed or characteristic hazardous waste during the neutralization process does not automatically bar the tank from the elementary neutralization unit definition. This tank is therefore eligible for the exemption for elementary neutralization units found at 40 CFR 264. 1(g)(6), 265.1(c)(10), and 270.1(C)(2)(v). Units qualifying for this exemption are not subject to permitting, generator on-site time limits, weekly inspections, or other technical RCRA standards. Since the elementary neutralization unit exemption applies only to the tank and does not attach to wastes that are removed from the unit, the F006 sludge formed during the neutralization process is subject to full regulation as a hazardous waste once it is removed from the tank for treatment and disposal.