Treatment Of Deicing Fluids

EPA has heightened its focus on commercial airports — a primer and a look at CAST


The Environmental Protection Agency recently developed regulations requiring large airports to collect and store spent aircraft deicing fluid (ADF), treat biologically or by distillation, and either dispose or recover it for reuse. Here, David Delasanta, the president of CASTion, provides background on deicing operations, EPA’s directives, and offers an in-depth examination of one method of mitigation. CASTion has partnered with Contego Systems, LLC, which specializes in eco-friendly methods of collecting spent deicing fluid.

Safety regulations require airplanes to be de-iced with propylene glycol during icy weather, but it can pollute water bodies, kill aquatic creatures, and contaminate drinking water.

Double-stage vacuum flash distillation in Controlled Atmosphere Separation Technology (CAST) achieves 95 percent recovery of 99 percent pure Propylene Glycol, and provides effective treatment with high reliability, low maintenance, and a high rate of return on investment.

The CAST solution operates at lower temperatures, uses less energy, has a smaller footprint and a quicker processing time than other distillation, and recovers for reuse valuable product that is destroyed in biological treatment.

Source of the Regulation

Congress passed the Federal Water Pollution Control Act Amendments of 1972 — also known as the Clean Water Act (CWA) — to ‘‘restore and maintain the chemical, physical, and biological integrity of the nation’s waters.’’ Congress recognized that regulating only those sources that discharge effluent directly into the nation’s waters would not be sufficient to achieve the CWA’s goals. Airports and their deicing operations will now be required by EPA to regulate their effluent into the environment.

Climate change induced by Global Warming is expected to cause more extreme weather events, including more ice storms and cold weather, leading to a greater need for deicing, and a greater burden on airports from these new regulations.

Since August 2009, the EPA has proposed technology-based effluent guidelines (ELGs) and new source performance standards (SPSs), under the auspices of the Clean Water Act. These standards were specific to the runoff resulting from airport deicing operations. According to EPA guidelines available on its website, “Deicing operations include removal of ice from aircraft, application of chemicals to prevent initial icing or further icing (anti-icing) and removal of (and preventing) ice from airfield pavement (runways, taxiways, aprons and ramps).”

Mandatory Deicing

The Federal Aviation Administration requires airlines to deice aircraft and airfield pavement to protect the safety of passenger and cargo operations. Aircraft deicing involves the removal of frost, snow, or ice from an aircraft. The responsibility for performing deicing/anti-icing varies between airports, but it is usually performed by a combination of individual airlines and support contractors — fixed base operators (FBOs) or ground service providers. EPA estimates that the 218 largest primary airports account for approximately 85 percent of the deicing fluid used nationally. The typical deicing season runs from October through April for most airports; in places like Minneapolis and Chicago, the deicing season may be longer.

Deicing Operations

Airlines typically select procedures for deicing/anti-icing their aircraft, which are then approved by FAA. Although the agency does not require airlines to use a specific technology when deicing, many airlines use aircraft deicing fluid (ADF). These ADFs contain ethylene glycol, propylene glycol, or urea compounds that contain ammonium. During typical wet-weather conditions, 150 to 1,000 gallons of ADF may be used on a single commercial jet, while as little as ten gallons may be used on a small corporate jet. An estimated 1,000 to 4,000 gallons may be needed to deice a larger commercial jet during severe weather conditions.

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