In the fall of 2010, an issue regarding deicing fluid in stormwater runoff into local tributaries from Gerald R. Ford International Airport (GFIA) came to a head, as local residents voiced their concerns. Over the past six years, the airport has worked to resolve the problem while maintaining transparency and keeping the needs of the citizens and environment at the forefront.
The heart of the issue is a chemical used to deice planes before takeoff called propylene glycol. Propylene glycol is not toxic and biodegrades naturally, but when it does so it competes with other organisms for dissolved oxygen in the water, and provides a rich food source for algae, fungi and other aquatic organisms allowing them to proliferate to nuisance levels.
The propylene glycol was creating a smelly biofilm on the surface of Trout Creek, a tributary of the Thornapple River. GFIA had no objection that their deicing fluid was contributing to the biofilm.
When the issue came to fruition, “[The airport] guaranteed that we would eliminate our contribution to the development of the biofilm,” said Tom Ecklund, engineering and facilities director at GFIA.
They considered several options to resolve the issue, but with encouragement from the West Michigan Environmental Action Council (WMEAC) among other local and regional organizations, GFIA settled on a detention pond with bacteria and fungi that will naturally break down the propylene glycol.
“Even though this is an engineered system, it utilizes natural features to help capture the flow of the deicing fluid, as well as stormwater runoff from the airport facilities,” said Elaine Isely, Water and LID Programs Director at WMEAC. “Our West Michigan waterways benefit from this type of innovative approach to improving water quality.”
Once the propylene glycol is broken down, the remaining stormwater is then to be discharged into the Thornapple River. Even though the chemical in question would be broken down by this time, there was still concern and controversy among local citizens.
“There was a lot of misunderstanding when we first indicated that this is what we wanted to do. A local media said ‘airport wants to dump all this stuff in the river,’” Ecklund said. “We had some work to do to convince the community that this was going to be beneficial for the environment.”
And this is exactly what they did. GFIA held countless public meetings to keep residents, and engaged organizations like WMEAC, up to date every step of the way throughout the entire project to ensure that they were satisfied with what was going on.
“We answered every question that we possibly could,” Ecklund said. “If we didn’t have an answer we made a commitment that we would find the answer.”
It took five years of planning, permitting, engineering and construction before the detention pond was completed in December of 2015. After the first winter in use, the discharge levels of propylene glycol were well below permitting levels from the Department of Environmental Quality (DEQ). With some fine tuning to the system, the discharge levels are even lower this winter.
This system is one of the first of its kind, and GFIA believes it may be an example and set a precedent for other airports nationwide to use natural means to solve similar issues.
The detention pond was not built only to meet bare minimum requirements, but was engineered with the foresight of expansion.“We wanted to build as much flexibility into the design as possible to accommodate for future regulations and become more efficient in our treatment as the airport continues to grow,” Ecklund said.
GFIA has received the “Outreach, Education and Community Involvement” award from Airports Council International, among other awards, but Ecklund maintains that, “That is not why we do things. We are most happy with the fact that it has worked the way it was intended to work from an environmental aspect.”
Last winter, GFIA gave a final wrap up meeting and tour to local residents. Only a third of those invited showed up to the meeting, which demonstrated to GFIA satisfaction with the results, and those who did show up initiated zero complaints.
Erv Gambee, president of the Thornapple River Watershed Council, stated in the GFIA Glycol System Treatment Report, “As a member of the Stakeholder Committee, I am happy with the final product that was debated, designed, engineered and built by the team. I look forward to seeing positive test results at the confluence of the discard and the Thornapple as well as the restoration of Trout Creek as time moves on.”