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ALEXANDRIA, Va.—Presentations at the American Association of Airport Executives’ (AAAE) 15th Annual Deicing and Stormwater Management Conference covered a wide range of topics, but a common thread was how airports will cope with the regulations currently being developed by the U.S. Environmental Protection Agency (EPA). These regulations, which will cover deicing activities at the nation’s airports, are scheduled for proposal next year and for promulgation in 2009.

EPA Project Manager Eric Stassler provided a progress report on development of the regulation and detailed the data collection efforts currently underway. In the past year, the EPA has conducted wastewater sampling at a number of U.S. airports to develop a technical basis for the rule. In addition, a round of detailed and "screener" questionnaires have been used to develop a technical and economic profile of the industry as a whole.

Case studies presented at the AAAE conference for airports in Milwaukee; Portland, Ore.; Buffalo, N.Y.; Akron-Canton and Toledo, Ohio; and Detroit underscored the general consensus that each airport will have to develop a unique strategy to address the environmental impacts of deicing activities. Along with the EPA rule, airport managers are feeling the pressure of stormwater regulations and an increased unwillingness by sewage plants to accept their glycol-contaminated wastewater.

Most of the studies focused on the practices currently used by airports to control and contain spent deicing liquids. The captured portion of these concentrated streams ranges from 20 percent to 50 percent of the total used for deicing, while the non-captured portion is left to stormwater, evaporation, infiltration, or unspecified loss. The case study for Buffalo Airport detailed the novel use of subsurface, aerated gravel beds for treating glycol-laden stormwater. These beds, also referred to as engineered wetlands, are designed to manage the fluctuating, seasonal flows from the airport.

Research presented by Steve Corsi with the U.S. Geological Survey examined the toxicity associated with deicing liquids. His research documented the toxic effects associated with the melt of glycol-laden snow banks. Further, the presentation probed the toxicity associated with the additives used in deicing liquids and concluded that much of the toxicity is caused by unknown proprietary ingredients.

Another topic that caught the attention of attendees was a presentation by Mike Arriaga of Boeing that detailed the negative effects of potassium acetate-based deicing liquids on airplane brakes. The accelerated damage of carbon brake systems associated with catalytic oxidation was graphically documented. Other presentations addressed alternatives to current deicing and anti-icing methods, and the laboratory methods available to analyze glycols in wastewater.

Presentations from the conference are available online at www.aaae.org/products/200_On-Site_Training/DeicingConference.html.

— contributed by Mark O. Liner, P.E., senior engineer
North American Wetland Engineering, LLC