Not so long ago around a third of all waste going to landfill originated from construction and demolition sites, according to official estimates. But in the past couple of decades, recycling and re-use has reduced this contribution massively. Current figures show that the UK recycles more of its construction and demolition (C&D) waste than most other EU countries. Some projects have recorded landfill diversion rates of more than 90% while the overall average rate in 2012 was a respectable 66.4%. That average rate is predicted to increase to 75.5% by 2020. An optimistic estimate, maybe, but still in line with the Waste Framework Directive which set a 2020 recycling rate target of 70% (by weight) for re-use, recycling and other recovery of C&D waste. Whether that target is achieved or not depends upon the industry raising its game 鈥� or turning to specialists such O鈥橠onovan Waste Disposal, one of a growing number of waste management firms that started out as demolition contractors.
London-based O鈥橠onovan was founded in the late 1950s by Joe O鈥橠onovan and is now headed by his daughter, Jacqueline, who is qualified as a chartered waste manager by the Chartered Institute of Waste Management. Over the past 10 years or more, legislation and changes in best practice have resulted in conscientious contractors installing colourcoded skips for on-site waste segregation 鈥� one for timber, one for plasterboard, another for masonry and so on. But in O鈥橠onovan鈥檚 view, contractors are often mistaken in favouring on-site waste segregation.
鈥淪ome customers like the idea of having waste sorted on site 鈥� and it does give the appearance that they鈥檙e taking recycling and sustainability seriously,鈥� she says. 鈥淏ut there are some very strong and compelling reasons why they should leave waste segregation to a waste management partner like us rather than entrust that to someone who might just want to get on with their own job, whether that鈥檚 drylining or laying bricks.鈥�
O鈥橠onovan points out that companies such as hers have the experience and the specialist equipment to carry out the task, with staff that are trained and qualified to identify, sort and recycle waste. This is more efficient, she says, because to do it on site requires staff to be trained and diverts them from their main construction tasks.
Consequently, O鈥橠onovan segregates 85% of its clients鈥� waste and only 15% of them choose to do it themselves on site. The company takes its clients鈥� concrete and masonry waste to its dedicated two-acre recycling plant in Tottenham, where it is crushed and screened for re-use. Scale is important here, argues O鈥橠onovan, because a client might consider the quantities from a specific site too small to recycle. 鈥淏ut we, on the other hand, will have a sorting bay for that specific waste stream so we鈥檒l segregate whether we have one or 21 skips of material.鈥�
Engaging a specialist contractor to handle all waste also minimises journeys and saves space 鈥� which can be a major consideration on the tight sites that are typical in London. 鈥淭here is only one skip or bin instead of several and there are fewer journeys to site saving fuel and reducing emissions because we don鈥檛 have to collect any containers that are not full to capacity,鈥� says O鈥橠onovan. 鈥淎nd we can offer a 鈥榳ait and load鈥� option so that there are no skips left on site 鈥� the lorry turns up and is filled there and then.鈥�
Employing a specialist also allows the client to demonstrate its recycling credentials; O鈥橠onovan issues a report detailing exactly what went where and what proportion did indeed end up in landfill. This can be presented on whatever basis suits the client 鈥� some might want the recycling statistics on each individual project while others prefer a monthly summary of their activities across several sites.
Before the WRAP Quality Protocol (see box) came in there was little or no regulation in the recycled aggregate industry, says O鈥橠onovan, so some companies were 鈥渘ot always very attentive with regards to the quality and knowledge of what they were actually processing鈥�. The WRAP protocol enables clients to audit suppliers to ensure compliance, resulting in a superior quality of recycled aggregate. This encourages both architects and surveyors to use recycled material rather than virgin aggregate, so making projects more sustainable.
An audit trail of the materials that come out of the construction site is also an important component of environmental assessment schemes such as RICS鈥� SKA scheme for office fit-outs and BRE鈥檚 BREEAM methodology. Waste management companies that provide clients with waste reports that show recycling levels of 90% and above, complete with a detailed breakdown of all the materials, can make a significant contribution to improving the rating that is awarded to a building, as Paul Tinton of Prowaste, another waste management specialist, points out.
There are two strong reasons to encourage continued growth in the use of recycled aggregates: the supply of virgin aggregates is limited; and the capacity of existing landfill sites is shrinking. The UK aggregates industry produces around 210 million tonnes of crushed rock, sand and gravel per year for construction use from over 1,500 quarries. But with current extraction rates of sand and gravel depleted by about 50%, there is no guarantee that production could match any hike in demand.聽
Partners in grime
Prowaste is a waste haulier and broker that has worked with O鈥橠onovan Waste Disposal for eight years, describing it as the 鈥榞o-to company for North London鈥�. 鈥淚ts recycling rates are phenomenal 鈥� way over 90%,鈥� says director Paul Tinton. 鈥淚t鈥檚 also important to the contractors who are our clients that this is documented, together with the breakdown of materials into the various waste streams, because these reports contribute to sustainability assessment schemes like BREEAM and SKA. They can then use these in tender documents to show that they have sustainable working practices and recycle聽materials.
鈥淟ondon is congested and floor space on site is restricted so in these circumstance it is correct to say that it is best to have simply one skip on site as it wouldn鈥檛 be costeffective to have, say, five skips for five different types of waste. Off-site waste segregation is the best option here. 鈥淭here鈥檚 also the issue of transport, where using the one skip or container will minimize journey times.鈥�
No space for skips
Geobond and Abtech Basements are two sides of the one business, one being the piling contractor while the other installs basements. Both use O鈥橠onovan Waste Disposal to remove the spoil, which is a mixture of soil, hardcore, timber and general builders鈥� rubble.
鈥淭he sites we work in don鈥檛 have room for more than one skip 鈥� if that,鈥� says director David Hilton. 鈥淎nd it wouldn鈥檛 be worthwhile in terms of transport and congestion either to have separate skips for segregating waste. 鈥淥ur staff are better employed carrying out their trades, not sorting out waste.
There are several ways in which you can segregate waste so they could make a mistake whereas the sorters at O鈥橠onovan do it all day.
鈥淲e find the company鈥檚 documentation very useful because we鈥檙e part of the Considerate Contractor鈥檚 Group and that requires us to document what happens to our waste and how much is recycled. With O鈥橠onovan we can just use its figures.鈥�
It鈥檚 a WRAP
In 2004 the Defra-funded charity WRAP (Waste & Resources Action Programme) published a Quality Protocol for the production of aggregates from inert waste, formulated in partnership with the industry.
This protocol helps ensure that recycled aggregate conforms to the appropriate European Standard and encourages its wider use by providing recycled aggregate suppliers with:
鈥� a procedure to control the quality of recycled aggregates for sale as construction materials, or as constituents in a product, e.g. concrete, asphalt and unbound mixtures
鈥� recommended minimum frequencies of inspection and testing conforming to the requirements of the European Standards for aggregates
鈥� the means for suppliers to provide adequate assurance that their products conform to relevant technical specifications and certified characteristics. As a result, the construction industry can use recycled aggregates with confidence, knowing that they have been subject to a rigorous regime of inspection and quality assurance.
This article first appeared in the April 2015聽issue of聽Construction聽magazine. To read the full magazine online,
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