Aircraft deicing methods and systems
The de-icing and anti-icing of aircraft and airfield surfaces -such as the Airport landing field- is required by the Federal Aviation Administration (AFA) to make sure those passengers will be safe. This activity is performed from October to May. It is necessary as we know that the snow and ice that stays in the landing field could prevent airplanes from having a safe landing; it could even cause major accidents. Nevertheless, not having discharge controls in place can result in environmental impacts. Airport and airplane de-icing are employed with the use of brines, salts, propylene, ethylene and other chemicals in order to remove and prevent or delay the formation of snow or ice.
This is an important task but the problem is that the chemicals of these deicing operations may drain off airport facilities to nearby lakes, rivers and bays. This situation impacts the quality of the water; it could even cause a reduction in dissolved oxygen levels (OD). This reduction can ultimately lead to fish kills. Regularly, airlines and fixed-base operators (such as contract service providers) are responsible for the de-icing of airfield pavement. But it is the Airport who is ultimately responsible for the management of the wastewater that is generated. Airports are required to obtain storm water discharge permits under the National Pollutant Discharge Elimination System (NPDES) Program and ensure that wastes from deicing operations are properly collected and treated. Because of the contamination of the water and the fish being affected, USEPA (The US Environment Protection Agency) has implemented new requirements for NPDES permits for storm water discharges related to the airport deicing. Bellow some of the methods:
Anaerobic bioremediation system
Cryogenic process: use of technology is allowed
Bio-detention basins: constructed wetlands and water quality ponds
Vapor transportation bed system: can be constructed above ground or under ground
Also, it has been said that the following bullets highlight significant issues associated with the current state of deicing system design in the US:
Central deicing pads provide better collection efficiencies than most at-gate types deicing runoff collection and require minimal associated labor. However, airlines operating non-hub operations and cargo airlines are generally unwilling to support pad construction due to concerns over delays.
Central wastewater treatment plants are almost always the most economical method of treating deicing chemical runoff, if sufficient biological loading capacity is available. Direct anaerobic discharge or anaerobic onsite pretreatment may be economical in capacity-limited situations.
Hybrid-deicing equipment and alternate PDMs offer significant near term BOD reductions that will almost assuredly translate to lower management costs.
Careful crafting of permit to lower management costs.
Careful crafting of permit upset provisions can significantly reduce the cost of management systems.
As it has been exposed, this is an important matter because not only the safety of passengers and flights has to be assured by the Airport de-icing systems, but also the safety of the environment: the water and the fish. The USEPA is currently conducting a study to determine if regulation of deicing fluid runoff is warranted on a nationwide basis.