Gerald R. Ford International Airport officials say its new deicing treatment system will significantly decrease the amount of glycol reaching the Thornapple River.
Gerald R. Ford International Airport Executive Director Brian Ryks and Facilities Director Thomas Ecklund met with members of the media last week in an effort to clear up what they termed misconceptions about the airport’s new deicing fluid treatment system.
Currently, airport runoff is discharged from a detention basin in the northeast corner of the airport into a tributary known as Trout Creek. Each year residents living along Trout Creek have noticed the formation of a biofilm on the river, which is a result of the propylene glycol from the deicing fluid.
Glycol is a sugar-based substance that is eaten by naturally occurring bacteria in the tributary, which then develop into a biofilm. Residents also have complained that its entry into Trout Creek has killed off fish and other creek wildlife, as well as emitting an unpleasant odor each spring as it dies off, following the discontinuation of de-icing activity for the season.
The Michigan Department of Environmental Quality has directed the airport to eliminate its contribution of glycol to Trout Creek by Oct. 1, 2015, in order to receive its next storm water discharge permit.
As a result, the airport is preparing to adopt the new $19 million natural treatment system, which will avoid Trout Creek altogether and instead direct the runoff through the new treatment system and then into the Thornapple River.
During several recent meetings, the public has expressed concern over the transfer of runoff directly into the Thornapple River. The main concern is that the new plan will cause environmental harm to the river. Residents would prefer the airport find a way to collect the deicing fluid without sending any of the glycol into neighboring rivers.
Ryks and Ecklund noted the runoff has always landed in the Thornapple River and said the new system would actually significantly decrease the amount of glycol reaching the Thornapple.
“For the last 10 to 13 years, we’ve had an average of about 36 percent going into the Thornapple,” Ecklund said. “When this project is completed, that is going to be reduced down to 7 percent.”
Ryks noted the 7 percent is mixed with 325 million gallons of storm water.
“It will significantly improve the quality of the water in the Thornapple from what it currently is today,” Ryks said. “We feel very good about it. It’s the first system of its kind in Michigan. It’s proven technology that has been instituted at a number of other airports.”
The natural treatment system consists of treatment cells through which the runoff travels. The vertical system includes a top layer of dry vegetation, followed by two layers of sand and then two layers of gravel.
“The proposed basin will act as a sediment trap and also act as a trash removal facility,” Ecklund said. “The flow will leave the basin, and the basin is designed to control the flow into the first set of cells. The flow will go through the first set of cells and receive treatment. It will then be discharged into the second set of cells where that treatment process will be duplicated. It will then go into a third stage of treatment, which is basically a riprap channel to add some oxygen into the flow, which is important to improve quality.”
Ecklund said the bacteria that feed on glycol would use the material as a food source during this process.
The airport will continue its collection and recycling program, which it said successfully collects 28 percent of the deicing fluid. Another 36 percent is not collectable as it stays on the aircraft, evaporates or biodegrades.
Other airports in the U.S. and Europe use similar treatment systems, some of which have been designed by the same team that designed this system.
Ryks pointed out the airport considered other options: building a centralized deicing pad, and discharging the runoff into the city of Grand Rapids Waste Water Treatment Plant.
He noted that constructing a centralized deicing pad would cost the airport almost double and would not improve collection significantly from what is currently being collected.
As for the city’s wastewater treatment plant, the pilot program conducted two years ago revealed the facility does not have the capacity to handle the storm water.
“We can’t separate the glycol from the storm water,” Ecklund said. “They’d have to be willing to take 325 million gallons of storm water that would overwhelm the Grand Rapids wastewater treatment plant.”
Ryks and Ecklund contend that, despite residents’ concern, the natural treatment system will actually improve the quality of the Thornapple River, and that the MDEQ requires testing of the Thornapple for two years to ensure the treatment system is, in fact, working as anticipated and within environmental regulations.
“It is important to note that this treatment system is something that has been used successfully,” Ecklund said.
The MDEQ public comment period on the airport’s proposed Clean Water Act permit remains open through June 28. The Federal Aviation Administration’s public comment period on the proposed Draft Environmental Assessment for constructing the natural treatment system also remains open through June 28.