Groups seek hearing on Mitchell International pollution discharges
They say waterways threatened by loose standards

Dec. 27, 2005 -- Environmental groups and residents who say Mitchell International Airport will be able to discharge too much pollution into area waterways under a revised state permit are trying to force a public airing of the issue.

One group, Midwest Environmental Advocates, says language in the Wisconsin Pollutant Discharge Elimination System permit the Department of Natural Resources has tentatively decided to issue is so weak that it violates federal water quality regulations.

The permit would require the airport to meet state water quality standards to "the maximum extent practicable," but MEA lawyer Andrew Hanson said federal regulations require the permit to ensure compliance with state and federal water quality standards.

The permit language "must be modified to require absolute compliance with water quality standards in Wilson Park Creek, the Kinnickinnic River, Oak Creek, and Lake Michigan," he said.

Friends of Milwaukee Rivers also has been pushing for a hearing on the proposed stormwater discharge permit, as has the Airport Neighbors Association.

Friends of Milwaukee Rivers Project Director Cheryl Nenn said Mitchell has "not been meeting the conditions of their last permit, especially pertaining to recovery of glycol. Instead of making their permit stronger, I feel that the DNR has weakened it or lowered the bar."

Glycol is used in plane deicers. The kind used at Mitchell, propylene glycol, uses high levels of oxygen during decomposition, which can deplete waterways of oxygen and kill fish.

Nenn said a public hearing would at least let members of the public have their questions about the permit be answered by DNR representatives.

Mitchell is required by its current discharge permit to try to capture 42.5% of glycol so that it cannot get into local waterways, according to the DNR.

The airport has consistently missed that goal, and has managed capture rates between 20.6% and 31.8% between 2000 and 2005, Hanson wrote.

"There has not been a trend toward better capture; the rate was 31% in 2003- 2004 but only 22.5% in 2004-2005," he said.

The proposed permit includes a 34% capture rate -- still higher than the airport has achieved, Hanson said.

The DNR said in a permit summary that "The airport is falling short of the goal, but continues to make improvements." The agency did not quantify the improvements further.