Akron-Canton Airport (CAK) in North Canton, Ohio, has served record-breaking numbers of passengers over the last several years, and has seen a rapid expansion in its aircraft operations as a result. Up to 3,000 aircraft per month are deiced each winter, with 300 to 500 gallons of deicing fluid applied to each aircraft. If significant quantities of the applied propylene glycol reach streams through the airport’s drainage system, the aquatic life in the water can be negatively affected. Prior to 2007, the airport did not have a system in place for managing and the environmental impacts of deicer fluids.
In response to the EPA’s National Pollutant Discharge Elimination System (NPDES) permit program, CAK engaged the project team, led by RS&H, in 2004 to evaluate the effectiveness and cost of potential deicer collection, storage and treatment systems. The system chosen is a state-of-the-art facility that is only one of three systems of its kind currently operating at airports worldwide. It consists of three components: (1) two contained-area aircraft deicing pads, (2) a deicer/storm water collection and storage system including two 750,000-gallon concrete storage tanks, and (3) a deicer fluid treatment plant featuring Anaerobic Fluidized Bed Reactor (AFBR) technology.
“Before starting,” GS&P project engineer Tim Arendt, P.E. explains, “the team built a sophisticated computer model in our Columbus office to simulate all the various possibilities for the different system elements. We looked at a lot of possibilities utilizing this homegrown model and basically found the system combination that would meet the client’s regulatory obligations while minimizing cost.”
The deicing pads include several in-pavement catch basins that capture the effluent, or runoff and overspray, and route it to diversion structures, as well as a system for monitoring the concentration of pollutants in the deicer fluid. Depending on the level of contaminants found, diversion valves release the effluent either directly into the storm sewer or to storage tanks for detention prior to treatment.
It was imperative that the tanks neither interfered with airport operations nor became aesthetically unbearable for neighboring communities. They were partially buried in an area that slopes downward from the main airfield, leaving only the domed roofs of the bulky 750,000-gallon structures exposed.
The team chose the AFBR treatment method due to its ability to treat high concentrations of glycol-contaminated effluent at a low operating cost and its environmental benefits. Prior to treatment, the effluent is heated and is then run through two 10-foot diameter, 32-feet high bio-reactors. Both reactors contain a community of anaerobic bacteria which “eat” the glycol, removing it from the contaminated runoff. Methane gas, a by-product of the bacterial buffet, is captured and burned in the plant’s boilers to heat incoming effluent and the building itself. The sustainable process nearly eliminates the plant’s reliance on external fuel sources.
The deicer management system serves as a model for effective, sustainable engineering. Covered extensively by local and regional news sources, as well as in business and industry-related media, the project has received an overwhelmingly positive response for its innovation, cost-effectiveness and green design. Local congressional representative Ralph Regula noted, “As a matter of public safety and responsible environmental stewardship, the Akron-Canton Airport is moving in the right direction with the introduction of this new technology to its operations.”
“This system goes beyond simply compiling with State mandates for water discharge by setting a new standard in environmentally friendly processes and recycling,” said airport director Rick McQueen. “The advanced engineering in this system will surely be helpful to airports around the country that are looking to CAK as a model to build their own deicing systems.”
As CAK continues to grow and expand as one of the Midwest’s busiest airports, the vast improvement to its deicer fluid collection, storage and treatment systems will stand as testament to the very best in engineering, design and civic responsibility.