Research into the environmental fate of aircraft deicing fluids under way at the University of Colorado at Boulder may result in new state limits on the discharge of deicing chemicals from Denver International Airport.
Unless specially collected in a storm water system, deicing waste is discharged directly into the environment, contaminating soils and threatening aquatic life. Recent surveys showed that often less than 50 percent of deicing fluids applied to aircraft are recovered and treated.
In Colorado, the setting of new effluent limits would require DIA to improve collection of deicing fluid waste and possibly take other measures to decrease the quantity of deicing-associated contaminants leaving the airport site, said Mark Hernandez, assistant professor in the department of civil, environmental and architectural engineering at CU-Boulder.
Hernandez and graduate student Cyndee Gruden are investigating the environmental impact of deicing fluid leaked into soils and water and the potential for on-site treatment of wastes through anaerobic, or bacterial, digestion. Maj. Jeff Cornell, who came to CU in 1996 on an Air Force Institute of Technology Fellowship, initiated the research, working with Hernandez to determine which components of deicing fluids are toxic.
Called "Balancing the Preservation of our Natural Environment with Mandatory Aircraft Deicing Practices," the project recently won a grant from the Lindbergh Foundation, based in Minneapolis. The research also is supported by the National Science Foundation, Denver International Airport and industry sources.
DIA contributed funds to the project after being fined by the state of Colorado last summer for leaking deicing fluid into Third Creek in Adams County.
"Corrosion inhibitors and surfactants present in deicing fluids are toxic to fish and other aquatic organisms even if deicing fluids are diluted by a factor of 1,000," said Hernandez, who presented the research findings last month at the Water Environment Federation's national conference in Orlando, Fla.
The propylene glycol-based fluid also can damage aquatic ecosystems by depleting oxygen in the water, he added.
With improved collection systems, however, more of the waste can be funneled into existing holding ponds on airport sites, where it can be pre-treated, lessening the burden on municipal wastewater treatment facilities, Hernandez said.
Hernandez' research shows that microorganisms naturally occurring in ponds can break down some of the fluid's toxic additives, which include corrosion inhibitors, surfactants and polymers.
The research is being watched closely by the Colorado Department of Public Health and Environment, which may set effluent limits on selected deicing chemicals or impose a zero discharge requirement on deicing fluid from the site.
Hernandez, who last year received a National Science Foundation Faculty Early Career Development Award for his work on microbial air pollution, joined CU's College of Engineering and Applied Science faculty in 1996.
His team's research on aircraft deicing chemicals was one of only 13 projects chosen for recognition by the Lindbergh Foundation this year, and the only winning project related to aviation, selected from more than 200 applications.
The highly sought-after grants are given in the names of Charles Lindbergh, whose epic New York-to-Paris flight captivated the nation in 1927, and his wife, Anne, who wrote many books and diaries. The Lindberghs believed there should be a balance between the advance of technology and preservation of the natural/human environment.
"We were really excited to get an aviation project of high quality that had significant ramifications for the environment," said grants administrator Marlene White.
Intended as "seed money" for large, long-term projects, the grants are awarded in amounts up to $10,580, a symbolic amount representing the cost of Lindbergh聮s aircraft, the "Spirit of St. Louis." So far, Hernandez' research team has raised $40,000 to match the Lindbergh grant and continue its work.