Glycol-contaminated stormwater retention pond and blower building at Calgary International Airport
The Calgary Airport Authority, which manages operation of the Calgary International Airport, has undertaken significant improvements at the airport, with the construction of the new 17-35 runway and the international terminal. The Airport Authority wished to treat stormwater contaminated with glycol de-icing fluid to meet environmental standards for stormwater discharge. Glycol is used to de-ice aircraft in the winter. The Airport Authority retained Associated Engineering as the lead consultant for project management, design, and construction services for the Glycol Treatment Facility, including civil, electrical, structural, and process/building mechanical systems. We also prepared the standard operation procedure and emergency response plan for the facility.
The Glycol Treatment Facility includes a large stormwater diversion chamber and pump station that are more than 10 metres deep. The diversion chamber intercepts glycol-contaminated stormwater discharged from the apron, and the pump station transmits the glycol-contaminated stormwater to a large aerated retention pond with 350,000 cubic metres of storage. The retention pond contents are aerated to provide primary treatment and address odours. Four 250 horsepower blowers in the adjacent Blower Building provide air for the retention pond. The Blower Building also houses a nutrient management system, and a programmable logic controller (PLC) system that monitors and controls over 200 inputs to the treatment process. The system is designed so that treated water can be recirculated through the pond for additional treatment, discharged to a secondary treatment process, or, during an emergency, discharged to the City of Calgary’s sanitary sewer system.
A second, 13 metre deep pump station with three pumps receives commands from the PLC system and controls the flow to the secondary treatment process. At the secondary treatment process, two attached growth reactor trains further treat the glycol-contaminated stormwater. Three 150 horsepower blowers in the Blower Building are dedicated to the secondary treatment process. The glycol concentration in the glycol-contaminated stormwater is continuously monitored through online instrumentation. Once the treated water quality meets City of Calgary guidelines, the treated water is discharged to the City’s stormwater system.
Project Manager, Joseph Chen, tells us, “The challenge for this project was completing the preliminary and detailed design and tender package within an aggressive 3.5-month schedule, followed by construction and commissioning in 7.5 months. The $20 million project had to be completed by October 31, 2016 to coincide with the opening of the new international terminal.”
We provided a dedicated team and developed a project management approach to meet the aggressive schedule. We used Autodesk Civil 3D and Plant 3D to facilitate a dynamic design environment, promote team communications, and help manage intricate design changes. We held a number of workshops, which included our technical team and the Calgary Airport Authority’s operation and maintenance, environmental, and engineering teams, as well as the construction manager. These workshops provided forums for collaboration to discuss issues, identify solutions, and develop a creative design to meet the accelerated schedule.
Joseph adds, “We considered the impact of climate change in our design. The pond is sized to handle a back-to-back, 1-in-100 year storm event, based on today’s standards, with capacity to accommodate more intense future storm events.” Although the facility resides on airport crown land, as part of the design, we evaluated potential impacts to the general public at the project boundary. Working with the construction manager, we developed solutions to minimize the impact on the public during construction, and to keep the pedestrian pathway open. We designed a pathway system that connects beyond the project site, resulting in an integrated and connected pathway system for the public.
Our key personnel on this project included Joseph Chen, Dave Anderson, Daniel du Toit, Joe Lisella, Scott Witzke, Zhong Di, Joe White, Corinne Arkell, and Mark Ingalls.