Prodded by the government, clients and the spiralling cost of landfill, contractors are getting better at recycling. we report on efforts to tackle aggregates, timber, plastic, plasterboard and glass
Recycling is happening. Pressure from clients, legislation and the rising cost of landfill means it makes more and more sense.
Also, site waste management plans – launched in 2004 by the DTI as guidance – are likely to be made mandatory next year. Mike Watson, head of construction at WRAP, says the industry has plenty of room for improvement, though the signs are encouraging. “There’s a long way to go but there’s increasing evidence of good practice. Some construction companies are looking to go beyond basic compliance. We’ve just run a series of workshops on site waste management plans for contractors and they were hugely popular.
“There’s a real recognition of the need to improve and a growing momentum to address issues of waste.”
How easy it is to recycle waste depends on the material. Some material recycling is already well established, such as scrap metal. The recovery of steel from demolition waste is between 85% and 99%. “Scrap metal has always been recycled well,” says Howard Button, national secretary of the National Federation of Demolition Contractors. “It now has such a high value that it’s really a commodity in itself rather than waste. That’s the key to solving the waste problem – reclassify recycled materials as products rather than waste.”
Barry Smith, environment manager at contractor Simons Group, agrees. “We need to reclassify waste. WRAP’s Quality Protocol really helped to do that with aggregates, and I’m expecting to see more protocols on other materials that will help to de-stigmatise waste.”
Over the following two pages, we take a look at the latest developments in the recycling of five types of material.
Aggregates recycling is well established. The UK is leading the way in Europe but there’s still plenty of room for development.
Andrew Summers, recycling manager for Tarmac in London and the South-east, has seen a change in the past few years. “There’s been a history of recycling aggregates in London for many years, because so much waste was produced that there had to be a way of dealing with it. But what we’re seeing now is interest in recycling in the home counties and rural areas as well. Contractors and developers have also started to reprocess on site, using a crusher or screener.”
“We’ve also developed FoamMaster in the last two years.” adds Summers, “It’s an aggregate with 95% recycled content. We use the waste from highways contracts to make the mix. It’s laid cold so saves energy and carbon emissions compared to hot asphalt production.”
Alan Young, engineering waste manager at Thames Water, says it is now taking a different approach. “We’ve been using recycled aggregates for a while, but we formalised it in December last year with our framework agreements and made it mandatory to use recycled materials. We specify using 30% recycled content in London and 15% outside. We’ve also set up our own material recycling plants to help us reach our target of sending 20% of our waste to landfill, and for the last 18 months we’ve been crushing and recycling waste from our projects and putting them back into the highway using stabilised material for reinstatement.”
Timber recycling is one area that is in real need of improvement, according to Barry Smith, environment manager at Simons Group. “You can get three or four uses out of it on site, but then what are you going to do with it? Send it away to be denailed, replained and so on and sent back to site? Because timber is a low-energy material, by the time you've transported it there and back and reformed it, you’ve used more energy than you've saved.
“A much more sensible use of waste timber is as wood fuel, then buy new timber from sustainable forests and support the forest industries. So you’ve also got to consider when is it appropriate to recycle and what is the best way of dealing with each material?
“If timber waste is declassified and turned into pellets for burning in wood burners, it would avoid the need to have a waste incinerator to burn it. We need to be thinking about how we can produce something that we can sell in Sainsbury’s.”
John White, chief executive of the Timber Trade Federation agrees. “The technology has moved on significantly, and this kind of waste wood can now be used as biofuel instead of going to landfill. A new biomass power station is about to open on Teesside, the UK's first purpose-built wood-burning power station, which will really help to develop this use for waste wood.”
This is one of the more difficult materials to recycle because it’s made of many different components, but there are some innovative products out there,
says Peter Maddox, manufacturing development programme manager at WRAP. “A more innovative use for recycled plastic is as kerbstones. These are lighter and more durable than concrete ones, and so don’t need heavy lifting equipment to place them.”
Bovis Lend Lease, with 3DM Worldwide and St David’s Partnership, has developed the ECO Board, a hoarding made from up to 80% recycled plastic. The boards are made of dirty, mingled plastic waste from sources ranging from supermarket plastic bags and industrial waste to electrical and electronic equipment, such as printer cartridges. This means there’s no need to separate the different plastic types and the board itself can be reused or recycled. The hoarding cuts down on the 5 million sheets of plywood per year used by the construction industry for temporary works, which is often shipped long distances.
Bovis trialled the board at the St David’s retail development in Cardiff, and is now looking into other applications for the board, including concrete formwork.
There’s been a real drive to recycle plasterboard waste from site since the EU Landfill Directive came into force in July 2005. Under the directive, any product with a high sulphur content – such as plasterboard – has to be separated out from other waste before being put into landfill.
Bob Stark, marketing and communications manager for Knauf, says the directive made a real difference. “This was a tipping point, because it meant there wasn’t much difference in cost or time between separating plasterboard to send to landfill and getting it recycled. And we can guarantee a fixed cost over a year for collecting offcuts, which a landfill site can’t do. We’ve definitely seen an increase in interest in the last six to 12 months.”
There is a limit to the recycled content of a board, however, as Stark explains. “At the moment, we can only use around 10% recycled content in our boards and maintain the same quality. Plasterboard is very highly regulated for fire and sound, so we have to make sure quality is maintained.”
British Gypsum set up a plasterboard recycling service four years ago and has seen increased interest in its services over the past two years. It is offering wheelie bins, skips and bags to collect the waste plasterboard, as well as running a service to return full damaged boards and offcuts.
It is also working on ways to reduce plasterboard waste through improved detailing and has launched a new door detail that cuts associated plasterboard waste by 50%.
Recycling glass from a construction site is tricky. Peter Maddox, manufacturing development programme manager at WRAP, explains why. “As well as there being an issue with collection, contamination is the main problem. Typically flat glass has been used for windows so often has PVC attached it. This makes it harder and more expensive to recycle and reuse the glass.”
There are, however, many building products that use recycled glass, including glass fibre insulation and aggregates and bricks. This is mostly lower-grade glass, usually from bottles, that isn’t suitable for recycling back into domestic use.
WRAP has carried out several trials with companies that make bricks incorporating recycled glass. Its partners include Stoneglass, whose high-recycled-content products are about to hit the market. It uses container, plate, automobile and cathode ray tube glass to manufacture bricks, pavers and cladding tiles with more than 97% recycled material. WRAP has calculated that the Stoneglass process reduces CO2 impact by one-third when compared with traditional clay counterparts.