A tighter treatment standard for cyanide and a reinstated standard for fluoride are included in a proposed Environmental Protection Agency rule on aluminum waste set for publication July 12.
The agency said it is not proposing to require the use of any particular treatment technology to achieve the standards, which reflect the levels achieved by best demonstrated available technology.
The proposal covers potliner waste, which is designated as K088 waste under the Resource Conservation and Recovery Act. Potliners consist of carbon and brick used to line the large vats for production of aluminum.
The agency is proposing treatment standards of 1.4 milligrams per kilogram total cyanide and 1.4 mg/kg amenable cyanide for K088 “nonwastewaters.” For fluoride, EPA is proposing a standard of 2.7 milligrams per liter in K088 nonwastewaters when measured by a version of the Toxicity Characteristic Leaching Procedure with deionized water as the leaching fluid.
Potliner waste “contains extremely high concentrations of these constituents, much higher than any of the other regulated constituents in the waste,” the agency said.
The current standard for cyanide is 590 mg/kg, according to EPA officials (118 DEN A-1, 6/19/00). The proposed 2.7 mg/L fluoride standard would reinstate the fluoride limit that existed before a federal appeals court in April 1998 vacated a 1996 rule on potliners ( Columbia Falls Aluminum v. EPA, 139 F. 3d 914 (D.C. Cir. 1998); 65 DEN A-7, 4/6/98).
“Cyanide and fluoride were two of the hazardous constituents for which treatment standard development had previously proved problematic,” EPA said in the new proposal.
EPA said it is not proposing to revise any of the other existing standards for potliner waste that were reinstated on Sept. 24, 1998, in response to the federal court ruling (63 Fed. Reg. 51,254).
There will be a 60-day comment period on the proposal, which also seeks to regulate potliner vitrification units “as RCRA Subpart X miscellaneous treatment units” and require air controls on these units. Vitrification units turn the waste into glass.
“Because new treatment units are likely to be needed to treat the 120,000 tons of K088 generated each year to achieve compliance with today’s proposed standards, the issue of the regulatory status of K088 vitrification units has arisen,” EPA said.
The agency is proposing to regulate the vitrification units as miscellaneous treatment units rather than as incinerators or industrial furnaces. EPA said coverage as incinerators is not ideal because the vitrification units can be heated directly by flame combustion or heated indirectly using electricity. Regarding the units as industrial furnaces also is problematic because there are elements of waste treatment in the vitrification process.
EPA also said it is proposing that the units be presumptively subject to maximum achievable control technology incinerator standards “as a point of departure in developing the suite of Subpart X permit conditions to be imposed.” The majority of available commercial K088 waste treatment capacity in the United States is at the Reynolds Gum Springs facility in Arkansas, which uses a thermal treatment system capable of treating approximately 120,000 tons of K088 waste per year and capable of meeting the Sept. 24, 1998, standards.
The agency said there is a K088 vitrification unit in operation at the Ormet Primary Aluminum Reduction facility in Hannibal, Ohio. A third facility, operated by Chemical Waste Management of Northwest Inc. in Arlington, Ore., uses a combination of chemical oxidation and stabilization to treat commercial K088 waste.
However, none of the above facilities would meet the more stringent proposed standards for K088 waste, EPA said. “At the present time, EPA estimates that approximately 80,000-100,000 tons per year of K088 waste would require alternative management to meet the proposed treatment standards,” the agency said.
Effective Date, Cost.
The agency is asking for comment on whether an effective date of two years after the final rule’s issuance is sufficient time to allow for adequate treatment or recovery capacity to become operational.
EPA said the total annual treatment costs for cyanide and fluoride attributed to the new proposal range from $12.4 million to $36.8 million. The agency said these estimates “represent only direct expenditures for treatment of cyanide and fluoride attributable to today’s proposed rule.” Because the treatment standards for potliners promulgated Sept. 28, 1998, have remained in effect, “treatment costs for spent aluminum potliner have already been accounted for,” EPA said.
Comments should be submitted to the RCRA Information Center, EPA Headquarters (5305G), Ariel Rios Building, 1200 Pennsylvania Ave. N.W., Washington, D.C. 20460. Comments should refer to Docket No. F-2000-TSSP-FFFFF.