Air travelers may not think much about what happens to the de-icing fluid that keeps planes flying in the winter. But airports, including Portland International, have to find safe ways to dispose of thousands of gallons of used product.
Here, airport officials are going to feed the waste to bacteria that love to eat de-icing fluid. The bacteria, or bugs, began incubating in September.
Susan Aha, who manages the project, hopes there will be enough bacteria soon to begin feeding them fluids being collected and stored on site now.
“There’s no other airport in the U.S. that’s doing what we are doing. We are not only collecting our aircraft de-icers we are collecting our pavement de-icers. And the reason is because of the really small capacity of the Slough. It’s very much site specific,” Aha said.
Last year, airline companies at PDX sprayed more than 60,000 gallons of glycol-based de-icing fluids on their planes.
“When they de-ice planes at the terminal the runoff from those planes goes into drains and the drains are connected to process piping that connects to our treatment plant,” Aha says.
In the past, the waste was diverted to the city’s wastewater treatment plant, which is at near capacity.
All of this year’s wastes are being stored at the airport. When there are enough bacteria to neutralize the waste, treatment plant operators will begin feeding the bacteria with this year’s waste.
The new treatment plant grew from the airport’s inability to stay within the limits of its wastewater discharge permit. The limits are set by the state Department of Environmental Quality, which isolated the airport’s problem in the 1990’s.
“They identified de-icing operations at the airport as one of the key contributors to low dissolved oxygen in the Columbia Slough, and when you get low dissolved oxygen it can be harmful to fish,” Aha said.
The airport violated its waste-water discharge permit for several years, and in 2006, it paid an $80,000 fine.
Aha says the new system should keep PDX in full compliance.