CFAC appeals discharge permit

The Columbia Falls Aluminum Co. has appealed new conditions to its wastewater discharge permit to the Montana Board of Environmental Review.

According to Montana Department of Environmental Quality legal counsel Kurt Moser, the company filed its appeal on Aug. 22, but the state’s hearing examiner has not issued any preliminary orders and no schedule has been set for a hearing.

DEQ issued a new wastewater permit for the aluminum smelting plant on July 25. The permit was to become effective Sept. 1.

Typically, wastewater discharge permits are updated every five years, and CFAC’s current permit was issued in 1999. A staff shortage at DEQ delayed the update process, and the permit was continued by administrative action.

The smelter completely shut down in October 2009, but the permit covers “outfalls” from several landfills and settling ponds that could be discharging hazardous chemicals into groundwater that eventually flows into the Flathead River.

CFAC’s attorneys in Bozeman cited five elements in its appeal, including changes made to the designated “mixing zones” for the 11 designated outfalls at the plant site. A “mixing zone” is a limited area of surface water or groundwater where discharge takes place and certain water quality standards may be exceeded.

The attorneys also claim DEQ’s revised permit does not take into account wastewater treatment achieved by the plant’s pond system or of pollutant dilution by natural soil and groundwater.

The attorneys also appealed DEQ’s new description for Outfall 006, a groundwater seep that collects in a natural trough northwest of the percolation ponds located between the plant and the Flathead River.

According to the 1999 permit, the groundwater at Outfall 006 runs beneath the plant and receives wastewater from the north, south and west settling ponds, drywells around the plant, several historic landfills, dust control discharges and several other sources.

Some of CFAC’s landfills contain spent potliner — bricks and carbon products that were used to line the plant’s 600 aluminum reduction cells. Spent potliner contains hazardous chemicals, particularly cyanide and ammonia.

The revised permit requires CFAC to collect a sample of the daylighting groundwater at Outfall 006 four times a year for acute toxicity testing. Acute toxicity is defined as when 50 percent or more of the water fleas and flathead minnows used in the tests die from exposure to various effluent concentrations.

CFAC is also required to test water samples from the Flathead River upstream of the plant for fluoride, cyanide, ammonia and benzo(a)pyrene — chemicals associated with aluminum smelting — as well as other chemicals and physical parameters.