Central De-icing Facility Pearson International

MARSHALL MACKLIN MONAGHAN CONSULTING ENGINEERS

Most airports in Canada were built long before environmental regulations governing contaminated water run-off were enacted. Consequently, many airports lack the infrastructure necessary to control the large volumes of spent glycol fluid they produce in de-icing planes. In 1994, studies conducted for Toronto’s Lester B. Pearson International Airport’s airside development concluded that the concentration of glycol in receiving waterways such as Etobicoke Creek during the winter was 50 to 100 times more than the acceptable biological oxygen demand (BOD) guidelines for the time.

Easing the environmental damage from de-icing can be done in several ways: by improving the equipment and techniques for applying the de-icing fluid, by centralizing and standardizing de-icing facilities, and by collecting and discharging waste glycol fluids appropriately.

Previously at Pearson, de-icing was done either on the apron just before the aircraft taxied to their take-off positions, or at the passenger gates. However, after testing the concept of having a central de-icing facility on a new taxiway extension, the Greater Toronto Airports Authority opted for that solution and asked Marshall Macklin Monaghan to plan and design the complex.

Built in 1997, the central facility handles all aircraft de-icing at the airport with the exception of minimal morning frost de-icing at the gates. The 65-acre complex — the largest of its kind in the world — has the capacity to de-ice up to six Class A aircraft (e.g. B747s) or 12 Class B (e.g. B737s) at one time. An equal number of aircraft can be staged in line behind, and if necessary those planes can be de-iced simultaneously.

Various methods are used to control and monitor the procedures from a central “fluid room” inside an operations control centre adjacent to the deicing pads. The control system is PLC-based and monitors fluid levels, and operates valves and equipment. Guiding the aircraft through the facility are locally controlled lighting systems and electronic variable message signs.

The environmental impact of de-icing is minimized in several ways. First, all active paved areas, amounting to 54 acres, have a geosynthetic liner to prevent glycol contaminating the groundwater. The surface and subsurface glycol run-off is collected in zones and directed to 15 diversion chambers. Using a computerized system, samples are taken at each diversion chamber to determine the glycol concentration and how it should be disposed of, whether sent to a low or high concentration holding tank or to a sanitary sewer line. The fluids with high concentrations are stored in 5 million-litre geosynthetic lined storage tanks until they can be loaded onto tanker trucks and taken off site for recycling or disposal.CCE

Owner: Greater Toronto Airports Authority

Design and environmental services: Marshall Macklin Monaghan (John Dejak, P.Eng., Ed Salenieks, P.Eng., Slavek Strzemieczny, P.Eng., Eugene Cionga, P.Eng., David Fan, P.Eng., Alf Schilter, P.Eng., Andy McRae, P.Eng., Alex Slywynskyj, P.Eng.

Architect: McMillan & Lowe