Where it comes from
According to a 2011 report from The Waste & Resources Action Programme, in 2010 up to 4.3 million tonnes (mt) of timber waste (not including ‘green waste’) was generated. This waste wood comes from a number of different sources including:
Wood waste from all sorts of building sites – including new builds and refurbishments – amounts to around 0.85mt per year (2010).
Most wood waste on these sites ends up in the skip along with all the other rubbish. The size of skips used typically range from 6 cubic yards (yd3) up to 40 yd3 (called “rolonofs”), but the most common size used is 8 yd3.
The big challenge with construction wood waste is that it is very variable. It consists of all sorts of different wood-type waste, including off-cuts of solid wood, broken pallets, bits of laminated chipboard, plywood, MDF and preservative-treated off-cuts. This makes construction wood waste harder to recycle conventionally, because in general these different kinds of wood wastes have to be recycled differently.
However, this also creates a perfect opportunity for Community Wood Recycling, because our small-scale, people-driven approach allows us to hand-sort wood and find the best use for each piece.
Each year, demolition also generates around 1mt (2010) of wood waste. Much of the stuff you will find in an architectural salvage yard – the old bricks, big chimney pots, fireplaces and butler sinks – has been rescued by the demolition industry. The demo’ game is highly competitive and the price of demolishing a building is usually heavily influenced by the value of the materials that can be salvaged.
In terms of recycling wood, their working practices are dictated by issues around speed and H&S. Previously, workers would have been happy to clamber up dangerous heights to cut down floor joists with a chainsaw, but nowadays it is very likely that a building will simply be taken down by large excavators with demolition claws and the material loaded straight into rolonofs for sorting at a waste transfer station.
The result is that less wood is saved; because it is not viable to hand sort it from the other demolished material. Like construction industry wood waste, it is of poor quality because it consists of so many different types of wood – and it will probably be mixed with plasterboard, plaster laths or other contamination.
Wood processing and manufacturing
This includes wood waste from timber mills, joinery shops and from fencing, furniture and other wood products manufacture and is estimated to total around 0.4mt (2010) per year.
Such businesses generating relatively small volumes of wood waste will usually have little trouble in finding people to take it away for firewood in winter and will use skips to dispose of the rest. Because this wood waste is relatively clean and unmixed, it is much easier to recycle than construction or demolition wood.
Some of the larger businesses producing this kind of wood waste reduce their disposal costs by having their own wood-fired heating systems.
Often, any sawdust or shavings generated from untreated wood will end up at a local farm to be used as low quality cattle bedding.
Increasingly, sawdust is seeing use recycled as ‘heat logs’ – compressed sawdust briquettes that burn hotter than logs and leave very little ash.
Pallets and wooden packaging
This amounts to around 1mt (2010) per year and includes packaging waste – such as crates, boxes and cable reels and a large proportion of the estimated 56 million (2009) pallets in the UK that are broken or just can’t be reused. Pallets are the easiest – and therefore cheapest – of all wood waste to recycle. They are usually ‘clean’ (untreated) and easy to handle (they can be loaded/unloaded by forklift), so every wood recycling company wants them.
Regulations were introduced in 1998 to force companies that generate more than a certain amount of this wood waste to recycle a proportion of it. If a company can’t do this themselves they are obliged to buy PRN’s (packaging recovery notes). These PRN’s are issued by the government to the end users of wood waste (such as the chipboard or biomass fuel industry) based on how much wood waste they recycle; they in turn sell them on to obligated companies.
Municipal wood waste
At around 1mt, this includes all the wood in the domestic waste stream that ends up at local tips (household waste recycling centres) where it is either mixed with the general rubbish and taken to landfill/incineration or separated into rolonofs and taken to a wood recycler. Very little re-usable material comes from this waste stream. It consists of items like broken furniture, old kitchen units, old fencing materials and bits of shed, much of which is preservative-treated or painted. Consequently it is the lowest quality of all the different wood wastes.
Where it goes
In 1992, less than 2% of all waste wood was recycled, but about 20 years ago technical developments in the chipboard industry meant that manufacturers could use a proportion of recycled wood in the ingredients for new chipboard (previously, it was made just from virgin timber). That stimulated the market for recycled woodchip and that’s when wood recycling pretty much began in the UK. Since that time other applications for woodchip have been developed.
For ease of understanding, we divide the wood recycling industry into 2 parts; high-volume wood recyclers (that simply chip all the wood they get) and community (low-volume) wood recyclers like us that focus on reuse.
The Wood Recyclers Association, a trade body made up of most of these high-volume wood recyclers, estimates that in 2011 around 2.8mt (or 60%) of all wood waste generated in the UK was recycled. To help find the most appropriate use for the recycled wood and provide guidance to those wanting to dispose of it, the WRA divides wood waste that comes into their yards into a number of grades; with each grade usually subject to a different gate fee:
- Grade A: “Clean” recycled wood – material produced from pallets and secondary manufacture etc and suitable for producing animal bedding and mulches.
- Grade B: Industrial feedstock grade – including grade A, but mixed with construction and demolition waste; this is suitable for making panelboard.
- Grade C: Fuel grade – this is made from all of the above material plus that from municipal collections and civic amenity sites and can be used for biomass fuel.
- Grade D: Hazardous waste – this includes all grades of wood including treated material such as fencing and trackwork and requires disposal at special facilities.
However many operators simply define wood waste as ‘clean’, ‘dirty’ – or mixed.
The woodchip produced is largely used in the following ways:
Chipboard and MDF
Around 38% (c.1.1mt, 2010) of all recycled wood is used in the manufacture of particleboard. There are five chipboard factories in the UK, located in Devon, North Wales, Merseyside, Northumberland and Ayrshire in Scotland. The industry still uses imported and home grown virgin timber, but absorbs more recycled woodchip than any other application.
To maintain the purity and consistency of their product and ensure that the (high tech and very expensive) manufacturing process is reliable, they want the cleanest, most uniform feedstock.
Hardwood, preservative-treated or painted timber, laminated boards, MDF or more than the smallest quantity of chipboard cannot be used to make new chipboard. And of course, the chip must be free from other contaminants, such as metal, grit, glass, plastic, or plasterboard.
Wood as energy
Trees absorb carbon dioxide whilst they grow, so burning wood for energy is considered ‘carbon neutral’. In 2010 around 0.55 mt (c. 19%) was consumed in this way, the majority in power stations to generate electricity. For example, Slough and Drax (N Yorkshire) power stations are coal-fired but have had some of their boilers converted to accept wood and they burn more than 100,000 tonnes a year of recycled woodchip.
Over the last few years, wood fired power stations have come on stream in south Wales, on Teeside and in Lockerbie, Scotland. Because of a government incentive scheme (called Renewable Obligation certificates) that offer financial incentives to generators to use biomass to produce ‘sustainable’ energy, more and more power stations are being commissioned to use this feedstock. In fact the industry predicts that once all the planned biomass facilities fire up, there will not be sufficient waste wood to supply them.
In addition to electricity generation, there are a growing number of schools, public, industrial and commercial buildings – and even homes – that have installed woodchip or wood pellet heating systems. As the cost of fossil fuels continues to climb, and environmental laws get tougher (and taxes higher), it is expected that using wood to heat buildings will become ever more popular.
The new power stations will be equipped with ‘scrubbers’ that can remove potential pollutants before they are released into the atmosphere, so they can burn a wider range of chip, including chipboard (that contains formaldehyde glue), painted wood – and even preservative-treated timber. The older power stations and smaller wood-fired boilers are not fitted with such equipment, so they should only be burning chips made from clean wood (although in reality some contamination does get through).
Because of these technical limitations and insufficient demand at home, an increasing amount of low-grade chip is now being exported overseas where wood-burning power stations are equipped with superior combustion and pollution control technology. This had led to a rapid increase in demand and a fall in the gate fees charged by wood chipping firms. However, because of the mild European winter in 2011, the market has been depressed and gate fees have risen dramatically and the market remains volatile.
This ranges from low grade, coarse woodchip for cattle stalls to very high quality dust-free chips suitable for sensitive, very expensive racehorses.
Bedding should be made only from clean softwood chips. So the best feedstock is pallets and packaging waste.
It should not contain sheet materials or painted/treated timber – as these could poison animals if ingested. In 2010 0.5mt (17%) of recycled wood was used for bedding.
Mulches, compost and coverings
Around (5%) 0.15mt of recycled woodchip is used as garden and landscaping mulch. Used to suppress weeds and help the soil retain moisture, it is drier and therefore does not rot down as quickly as mulches made from tree bark or virgin woodchip. Coloured mulches are also becoming popular.
Woodchip is also added to green waste compost. A plant’s leaves contain mostly nitrogen, whereas wood is mainly carbon. Adding woodchip improves the carbon/nitrogen balance – essential for good compost. Much of this compost is relatively low quality and is used as ‘soil improver’ on farmland.Woodchip is used for paths and tracks on farmland and in countryside car parks, and the lowest grade chip is used as a cover for landfill sites. Wood recyclers will probably make mulches using the lowest quality of wood waste they can get away with, and mulches invariably contain at least a small amount of sheet materials, painted and preservative-treated wood.
Paths, rides and arenas
Woodchip can be used for forest paths and rides and for horse gallops and arenas. The chip does not have to be so clean and can contain preservative-treated wood (which is an advantage because it does not break down so quickly) and small amounts of sheet materials. It must be free from metal, glass or grit – which could be dangerous to horse and rider. In 2010 0.092mt (3%) of woodchip was used in this way.
In 2010 estimates, 0.54mt (18%) of woodchip were exported abroad, mainly for use as fuel.
The challenges of wood recycling
High volume wood recycling is expensive; a new chipper can cost anything between £120,000 and £250,000. Then, to take out the ferrous (screws, nails, bolts etc.) and non-ferrous metal (hinges, door furniture etc.) expensive magnets and eddy-current separators will be needed, along with a screen to ‘size’ the woodchip correctly for each of the above uses. Obtaining suitable premises, licensing, additional equipment, insurances and other costs mean that wood recycling is a capital-intensive business.
As the chipboard, wood-for-fuel, and most bedding markets only pay around £40–£80 per tonne for woodchip, to make their businesses pay wood recyclers need to process huge quantities of wood waste. To get these volumes and to keep costs as low as possible, they focus on servicing organisations that are high-volume generators of wood waste such as skip and pallet companies, distribution companies and large furniture or wood products manufacturers. They don’t really want lots of small loads arriving in builders skips, so they don’t usually service the building industry directly, so they aren’t in direct competition with us community wood recyclers.
Rather than going direct to a wood recycler, the relatively small skip loads from building sites are far more likely to be taken to a waste transfer station.
The traditional wood recycling industry as described above makes a fantastic contribution to waste reduction by recycling huge quantities of waste wood that might have been landfilled. However, Community Wood Recycling believes that this precious resource should be cherished and reused for as long as possible before ending its life as woodchip, so we work hard to ensure that any wood which is still suitable for use goes back to the community.
Community wood recycling complements high volume wood recyclers by providing organisations that generate relatively low volumes of waste wood an environmentally and socially superior way of dealing with their waste.
WRAP is a charity that works with businesses, individuals and communities to achieve a circular economy through helping them reduce waste, develop sustainable products and use resources in an efficient way. Wood reuse and recycling in the UK is an area with poor access to public information so we’re very grateful to WRAP for providing us with these insights.
The WRA is a trade body of bulk wood recycling businesses whose aim is to represent the wood recycling industry and its interests.