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JUN 4, 1984
Status of Supernatant from Lime Neutralization of Spent Pickle Liquor
Matthew Straus, Acting Chief Waste Identification Branch (WH-562B)
Karl Klepitsch, Chief Waste Management Branch (Region V)
This memorandum addresses your inquiry regarding the status of supernatant from lime treatment of spent pickle liquor.
First, you are correct in stating that the supernatant is not included in the industry-wide exclusion of lime-stabilized waste pickle liquor sludge (LSWPLS) (formerly known as lime neutralized waste pickle liquor sludge) generated from the iron and steel industry. The exclusion pertains only to sludge generated from the treatment process.
Second, the supernatant is a hazardous waste. However, it is not regulated when stored in a tank connected to the wastewater treatment system. (This material is generally stored in a sedimentation tank (clarifier) prior to discharge). In addition, when discharged, the supernatant is excluded from the presumption of being a solid waste, and thus, a hazardous waste (see 40 CFR 261.4(a)(1)(ii)(2)), if it is discharged either to navigable waters pursuant to the provisions of the Clean Water Act or to a POTW. Supernatant that is removed from the wastewater treatment system, and is otherwise managed, is regulated under RCRA.