Transportation, Environment, United States, North America, Government
Transportation + Environment
Dissolving Deicing Chemical Concerns
Addressing U.S. EPA Draft Effluent Limitation Guidelines
For airports, deicing chemicals are a necessary evil. Required to ensure public safety, the chemicals create environmental concerns due to runoff and contamination. Compounding these issues are the draft effluent limitation guidelines (ELGs) for deicing and anti-icing chemical discharges recently released by the U.S. Environmental Protection Agency.
Operational flexibility was a critical component. Working with CDM Smith, we were able to develop a cost-effective design that will have significant environmental benefits once it is operational.
The guidelines are prompting some airports to proactively address stormwater and deicing chemical runoff. CDM Smith is collaborating with two such airports—Pittsburgh International Airport (PIT) in Pennsylvania and Portland International Airport (PDX) in Oregon—to create unique onsite collection and water treatment systems.
Unique Solution for Complex Concerns
Collection systems and best management practices at PIT capture 60 percent of spent deicing chemicals. However, chemicals that drop off taxiing or departing aircraft can migrate into onsite streams and negatively affect water quality and native species. The airport needed a cost-effective approach to properly collect and treat these “fugitive” chemicals.
CDM Smith designed a first-of-its-kind solution that collects stormwater runoff via new in-line retention basins and pump stations, then transports it to a biological treatment plant. Treated water is released into one of the onsite perennial streams. Improving onsite water quality allows Allegheny County Airport Authority to reduce environmental impacts and preserve wildlife, as well as meet criteria set forth by a Pennsylvania Department of Environmental Protection consent order.
“This project is unique because regulatory agencies typically look at specific storm events within a collection area. Based on the size of our collection area, we quickly discovered that a solution using this approach would be cost-prohibitive. CDM Smith worked diligently to demonstrate to the agencies that a percent-load-reduction strategy would meet compliance needs and still be affordable,” says Kevin Gurchak, manager of environmental compliance, Allegheny County Airport Authority/Pittsburgh International Airport.
With the entire system expected to be online for the 2012/2013 deicing season, the airport is exploring additional funding opportunities through the Federal Aviation Administration (FAA) and the American Recovery and Reinvestment Act.
Collaborating for Success
At PDX, an expanded collection and conveyance system, new onsite treatment system, and new discharge outfall will better manage deicing stormwater runoff. Working under a fast-track project schedule, CDM Smith completed a comprehensive study, alternatives evaluation, National Environmental Policy Act assessment and system design.
Since the airport is bordered by the heavily protected Columbia River and Columbia Slough, CDM Smith coordinated with multiple agencies—FAA, U.S. Army Corps of Engineers and Oregon Department of Environmental Quality—to address environmental regulations. Creating a new river outfall to discharge deicing stormwater runoff requires boring under a federal levee, necessitating extensive permitting.
According to Susan Aha, deicing program manager for Port of Portland, the authority responsible for overseeing PDX, stakeholder engagement is extremely important to this project. “We are situated between sensitive water bodies in an area with environmentally conscious citizens,” explains Aha. “The CDM Smith team did an excellent job supporting our work with airline carriers and community stakeholders, including environmental groups, the city of Portland and watershed councils.”
Airport stakeholders, including five major carriers, were involved in the design and review process. This helped to maintain good relationships and kept costs down—particularly important to the Port of Portland, which is committed to environmental compliance and being a good community neighbor.
Preserving the Environment, Protecting Passengers
In addition to designing the new onsite anaerobic digestion treatment plant for PDX, CDM Smith is managing strategic upgrades to the existing collection system infrastructure. New collection points, pumps, pipes and storage tanks offer flexibility in managing deicing discharge and stormwater runoff. “Operational flexibility was a critical component. Working with CDM Smith, we were able to develop a cost-effective design that will have significant environmental benefits once it is operational,” says Aha.
After capture, runoff is sent to concentrated or dilute storage, followed by treatment and metering to either the river or slough. In-line monitoring equipment identifies chemical concentration and flow rate and considers permit limits and weather predictions to determine the most appropriate option for storage, treatment and release. The airport can treat concentrate onsite, transport it offsite for treatment at the local treatment plant, or directly discharge dilute runoff if treatment is deemed unnecessary. Additional captured runoff will be sent to covered storage tanks, rather than uncovered basins, reducing bird-strike risks and improving public safety.
Design is complete and construction will begin in spring 2010, with the entire system fully operational in time for the 2011/2012 deicing season.
Creative, Customized Solutions
While the specifics will vary due to climate, topography, operations and budget, an onsite collection and treatment system can be tailored to meet an airport’s unique needs. Through collaboration, CDM Smith is providing cost-effective, customized solutions with big environmental rewards. And, with ELGs soon to become law, other airports will have to explore similar solutions to ensure environmental compliance.