State reviewing wastewater permit for CFAC
Changes might be in store for the state wastewater discharge permit for Columbia Falls Aluminum Co.
The Montana Department of Environmental Quality issued a public notice about the plant’s permit on Feb. 18. Typically, wastewater discharge permits are updated every five years, and CFAC’s current permit was issued in 1999.
A shortage of manpower at the state agency delayed the permit update process and the permit was continued by administrative action.
The plant has been shut down since October 2009 but the permit covers “outfalls” from several landfills and settling ponds from which hazardous chemicals could seep into groundwater that eventually flows into the Flathead River.
Some of the 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 state permit covers 11 outfalls at Columbia Falls Aluminum. Two are for cooling water at the paste plant and casting plant; one is for CFAC’s sewage treatment plant; others include noncontact cooling water, boiler blowdown, stormwater drainage and incidental discharges.
As part of the permit update, the Department of Environmental Quality proposes adding a new outfall for cooling water used for the sow casting line installed in 2006.
Groundwater that flows beneath the plant to the Flathead River receives wastewater from several settling ponds, in addition to drywells, steam-cleaning sumps, landfills, a septic system and other small sources.
The Department of Environmental Quality also proposes new requirements for “an acute surface water mixing zone for ammonia and chlorine,” and for “a chronic surface water mixing zone for cyanide, as well as aluminum, ammonia, antimony, benzo(a)pyrene, chlorine, copper, fluoride and nickel.” Benzo(a)pyrene is one of many complex compounds associated with the carbon products made in the smelter’s paste plant.
In addition, the agency proposes adding aluminum and cyanide limits for a groundwater seep that collects in a natural trough northwest of the percolation ponds between the smelter and the Flathead River.
Additional monitoring has taken place at 10 groundwater monitoring wells and two riverbank monitoring sites. Samples have been collected by CFAC’s full-time environmental manager and sent to a lab for testing.
The Environmental Protection Agency also is collecting samples for lab testing, but it’s not for a wastewater discharge permit.
The EPA testing is part of a Superfund-related investigation requested by Montana’s U.S. senators. The timing of the permit update is considered coincidental by Department of Environmental Quality staff.
Public comments for CFAC’s permit No. MT0030066 can be mailed to DEQ Permitting & Compliance Division, Water Protection Bureau, P.O. Box 200901, Helena MT 59620 or e-mailed to WPBPublicNotices@mt.gov. April 4 is the deadline for comments.
Hanners is the editor of the Hungry Horse News.