CFAC's wastewater permit due for update

Changes might be in store for the wastewater discharge permit issued by the state to the Columbia Falls Aluminum Co.

The Montana Department of Environmental Quality issued a public notice about the smelter’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 DEQ delayed the permit update process, and the permit was continued by administrative action.

The smelter has been completely shut down since October 2009, but the permit covers “outfalls” from several landfills and settling ponds that could be seeping hazardous chemicals 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.

All told, the DEQ permit covers 11 outfalls at the smelter. Two are for cooling water at the paste plant and casting plant; one is for the plant’s sewage treatment plant; others include noncontact cooling water, boiler blowdown, stormwater drainage and incidental process discharges.

As part of the permit update, DEQ proposes adding cooling water used for the sow casting line installed in 2006 as a new outfall.

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.

DEQ also proposes including 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, DEQ proposes adding aluminum and cyanide limits for a groundwater seep that collects in a natural trough northwest of the percolation ponds located 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 is also collecting samples for lab testing, but it’s not for a wastewater discharge permit. The EPA’s action is part of a Superfund-related investigation requested by Sen. Jon Tester and former Sen. Max Baucus. The timing of the DEQ permit update is considered coincidental by DEQ 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. Deadline is April 4.