Dealing with large volumes of construction and demolition waste can be challenging but what about at one of the world’s busiest airports? Katie Coyne finds out more
Heathrow is classified as the world’s third busiest airport, according to Wikipedia. So while dealing with construction waste at the site is, on the face of it, much the same as on any large scale engineering project it is also a challenge to keep the airfield operation unaffected. Yet from 2010 to 2012, Heathrow’s overall construction waste recycling rate increased from 85% to 95%.
During the demolition and build last year of Terminal 2 (T2), for example, over 21,000 tonnes of construction waste was produced - and more than 90% of this was recycled.
“There are considerable volumes of waste involved,” says Mark Robertson, waste and environment manager at Heathrow Airport. “But we were fortunate as we have probably got five or six businesses fairly local to the airport that are fully committed to taking that sort of construction waste and crushing it, grading it and re-using it.”
Heathrow uses local merchant facilities for recycling all types of inert construction waste including the Powerday MRF at Old Oak sidings. “There’s always been a lot of construction in this area partly because of the airport - it’s a good position for us to be in because we get a competitive price,” Robertson explains.
Around 449,000 cubic metres of clay from T2 was used for landfill remediation at a local site. Meanwhile, the demolition and concrete rubble produced was crushed on site to class 6F standard and used as capping material across the whole T2 project. The material used was in full compliance with the WRAP Aggregates Quality protocol.
“We tried to re-use as much as we could in the rebuild and in the foundations and runway as sub-base material - obviously making sure it was a certain grade,” adds Robertson.
The design and fit-out of T2 was based around standard sized pre-fabricated building components to reduce waste. Plasterboard metals, for example, were spaced at 600mm intervals to accept standard width plasterboard sheets without cutting and creating waste.
Terminal Two’s satellite building excavation produced 600,000 cubic metres of sand and gravel. Of this, 80,000 cubic metres was re-used in foundations for buildings and aircraft stands. The remaining 520,000 cubic metres was sold for concrete batching at a plant in Shepperton.
As part of the T2 development, 100% of the pavement quality (high strength concrete) was broken out of the Queens Terminal (T2A) and recycled as wet lean concrete for road pavements or type one sub-base for re-use at Heathrow. Around 30,000 cubic metres has been re-used at the airport.
Heathrow plans to have dedicated facilities for the recycling of waste from construction and engineering projects, such as a specific recycling facility for concrete and road sweepings from construction sites on the airport.
Robertson adds that the airport is proposing a strategic objective around construction waste to recycle 20% of non-operational hazardous waste by 2020 compared with 2010.