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Vehicle Recycling & The Environment
There were around 30 million motor vehicles in use within the UK in 2002. Every year, approximately 2 million new vehicles are registered and a similar number are scrapped.The average lifespan of a car is 13.5 years and in 2000, just over 2 million cars and vans reached the end of their useful lives, either because of old age or due to accident.
The composition of a typical car has changed substantially in recent years. For example, ferrous metal content has decreased significantly as lighter, more fuel-efficient materials such as plastics are incorporated into vehicle design. An analysis of vehicle manufacturer data for around seventy popular 1998 car models shows the following breakdown of materials (by weight).
Source: ACORD, Annual Report, 2001
Over 50 million tyres (just over 480,000 tonnes) were scrapped in the UK in 2001 and around 80,000 tonnes was disposed of in landfill.
The reuse of parts and the reclamation of materials from motor vehicles is not a new industry. Metal parts in particular have for a long time had a value, either in terms of reuse or recycling. When a car reaches the end of its useful life it usually passes to a vehicle dismantler. The dismantler will remove parts that can be sold for reuse, remove the potentially environmentally polluting materials such as operating fluids and batteries, and then sell the hulk on to a shredding operation. Shredders are high capacity hammer mills that break the hulk in to fist-sized parts. Ferrous metals are then removed by magnetic separation and non-ferrous metals are sorted both mechanically and by hand. The proportion of ELVs currently recycled is much greater than any other consumer product; even so, around 408,000 tonnes of remaining material is buried in landfill sites each year. This material is mainly made up of plastics, rubber, glass, dirt, carpet fibres and seat foam.
Recovery and disposal of individual components
- Parts reuse
Accident damaged and end of life vehicles have many perfectly serviceable parts that can be removed and reused. The motor vehicle dismantling industry has been doing this for years and can provide such things as………
Doors, Bonnets, Wings, Bumpers, Headlamps, Rearlamps, Alternators, Starters, Electronic modules, Wiring, Relays , Gearboxes, Drive-shafts, Prop-shafts, Differentials, Engines, Cylinder Heads (to mention just a few) at great savings both to the environment and to customers.
As businesses have become both more professional and more sophisticated the uncertainty associated with buying recycled parts has disappeared. The advent of computers and internet linked parts locating systems has made finding the right part simple and modern freight services mean that next day delivery is now the norm.
The reuse of vehicle parts is going to be a significant factor in helping to achieve the 85% and 95% recovery targets set by the European End of Life Vehicles Directive.
- Metals
Approximately 76% by weight of the average car is metal, most of which is comprised of sheet steel. The overall metal content of cars has declined rapidly during the past 20 years accompanied by an increase in the proportion of non-ferrous metals used in their manufacture, such as aluminium and magnesium. Currently about 98% of the metals in a car are recycled. These metals are recovered by the dismantling and metals recycling industries and are subsequently recycled by the steel industry and re-smelting plants in the production of new steel and secondary metals such as aluminium and copper.
- Plastics
Plastics used in the car industry have risen considerably, where an average new car in 1984 contained 8.5% by weight of plastics a similar car today contains around 11%. Plastics are used for their distinctive qualities, such as impact and corrosion resistance, in addition to low weight and cost. Due to its lightweight properties, the use of plastics can lead to considerable energy savings, with a car weighing 1.3 tonnes without plastics consuming approximately an extra 1000 litres of fuel during its life compared to a car weighing 1.1 tonnes with plastic . Despite the relatively high recycling rate for ELVs, the proportion of plastics from ELVs being recycled is extremely low. One reason for this is the wide variety of polymer types used. Identification, by marking components at production or by improved sorting technologies, will be vital if the practice of recovering plastic parts is to become viable. One of the few plastic parts currently being recovered from ELVs is battery cases, accounting for 5,000 of the 14,000 tonnes of automotive plastics recycling in 1998. There is an estimated further 121,000 tonnes of automotive plastics which is currently landfilled.
The most common automotive plastics types are polypropylene (PP), polyethylene (PE), polyurethane (PU) and polyvinylchloride (PVC). PP accounts for approximately 41% of all car plastics (common in bumpers, wheel arch liners and dashboards), and like PE and PU (most common in seat foam) it is easily recycled. Viable markets for PP, PE and PU from non-automotive sources already exist.
PVC makes up about 12% of the plastics content of an average 1990s European car. PVC, by contrast, is relatively difficult to recycle, and there are currently no large-scale recycling schemes operating for post-consumer PVC. Alternative disposal methods such as incineration have raised a number of environmental concerns including dioxin emission during incineration and the use of phthalate plasticisers, which are thought to be disrupters of hormone systems. Car manufacturers are currently looking for alternatives to PVC.
- Vehicle operating fluids
This is one of the areas of greatest concern regarding motor vehicles. Although the disposal of fluids from ELVs is a major issue, the effects of inappropriate treatment of fluids removed during servicing are also significant. Increasing amounts of engine oil are being recovered and recycled however less than a third of waste oil produced by the DIY motorist is recycled. Lubricating oil has the greatest pollution potential.
Much of the waste oil collected for recovery in the UK is processed (by removing excess water and filtering out particulates) and used as a fuel burnt in heavy industry and power stations. However, stricter emission limits and fuel quality controls resulting from environmental legislation could mean a reduction in the amount of waste oil used in this way. The preferred option for lubricating oils is re-refining for reuse as a base lubricant, although this doesn't currently occur on a large scale in the UK.
There are 1,500 Oil Recycling Bins in Britain for lubricating oil only. Call the Oil Care Campaign on 0800 66 33 66 or use the post code search on their website www.oilbankline.org.uk to find the location of you nearest oil bank.
- Oil filters
When removed, oil filters can retain large amounts of oil and this may be discarded with the filter leading to further pollution. Vehicle dismantlers are required to remove oil filters. Oil can be recovered using special oil filter presses which squeeze out the oil and the remaining flattened metal filter can be recycled with other steel. Oil filter crushers are available for use on site at garages, although this is currently not common practice. Nevertheless, it is hoped that oil filter crushers will be increasingly introduced into civic amenity sites as an added service to the DIY car mechanic.
- Catalytic Converters
Catalytic converters ('cats') have only been fitted as standard in new petrol injected-engine cars since 1992, so the business of their recovery is still developing. In the US, there is a well-established network of agents who collect the cats and a similar system is developing in the UK. The steel from the exhaust and the precious metals from the cat can be recovered when the cat is replaced. Platinum, rhodium and palladium can be recovered for reuse, either in new auto cats or for some other purpose, and as 68% of platinum and 90% of rhodium used in Western Europe go into the production of catalysts, this business is extremely viable. The ceramic casing is also recovered as a powder for refining.
- Batteries
EC Directive 91/157/EEC requires the separate collection of certain batteries, including those containing more than 0.4% lead by weight, which includes vehicle lead acid batteries. There is a well-established system for the recovery of lead acid car batteries with many local authorities and garages having collection points. The recycling rate for car batteries is estimated to exceed 90%. However, a significant number of batteries are still not recovered and recycled (for example, many scrap cars still contain batteries when they are shredded). A revision of the existing battery legislation is currently being undertaken. EU proposals include a 70 - 100 % collection target for automotive lead acid batteries with a recycling target of 50 - 80%.
- Secondary Restraint Systems
Secondary restraint systems used in vehicles consist of airbags and seat belt pre-tensioners. Air bags became standard components in UK-produced vehicles in 1993. Some air bags are only activated as a result of certain types of collisions, so occasionally the bag is undetonated and in the absence of manufacturers' deployment instructions, a strict procedure should be followed in order to disarm the bag safely.
- Glass
In 1999, ELV arisings reached 1.8 million. With glass constituting approximately 3% of a vehicles weight, in excess of 55,000 tonnes of automotive scrap glass were theoretically available for recycling. This figure is likely to be increasing with the rise in ELVs. Currently, in the UK the majority of ELV glass is sent to landfill and only a small proportion is recycled.
There are two types of glass used in the auto industry, toughened and laminated. Toughened glass is easy to remove from vehicles after shattering. Laminated glass, however, doesn't shatter and will need to be removed manually, which is time-consuming. In addition, as the value of glass is relatively low (approximately £0.48 per ELV), it is currently not possible to recover the cost of removing glass.
- Tyres
Tyres consist mainly of steel, rubber compound and textiles (often in the form of cotton). The typical composition of tyre rubber is as follows:
| Tyre Composition |
% Weight |
| Rubber hydrocarbon |
51 |
| Carbon black |
26 |
| Oil |
13 |
| Sulphur |
1 |
| Zinc Oxide |
2 |
| Other chemicals* |
7 |
* Includes inorganic fillers, organic vulcanisation activators and accelerators, and processing aids.
Source: Opportunities and Barriers to Scrap Tyre Recycling, AEA Technology Report, 1994
Tyres account for around 3.5% of the weight of an average ELV, and as a controlled waste under the Environmental Protection Act 1990, a Duty of Care is placed upon waste producers to ensure that waste material is disposed of safely through registered carriers to licensed sites. According to the Used Tyre Working Group's 2001 survey 22% were recycled, 8.3% went to energy recovery, 9.9% were retreaded, 16% were reused and 3.3% were used in landfill engineering. The remainder (approximately 40%) will have been landfilled, stockpiled or illegally disposed of.
Tyre disposal options:
Waste prevention is a primary objective when looking for future developments in scrap tyre options. Ongoing research into improvements in tyre design and construction has resulted in the life expectancy of tyres continuing to lengthen.
Reuse of part-worn tyres
Extracting the maximum safe life from a tyre saves valuable resources (oil, rubber, steel etc). Before the tyre can be resold it must be checked. Part-worn-tyres must have a minimum of 2mm tread remaining and be marked as part-worn on both sides at the time of sale.
Reuse through landfill engineering
Whole tyres can be used in the preparation/construction of landfill sites, where they are used as leachate draining systems. Tyres used for this purpose are exempt from the landfill tax. Between 1998 and 1999 there was a 20% growth in the use of tyres for landfill engineering.
Recycling through retreading
Tyre retreading is a major industry in the UK. Retreading involves either replacing only the tread section or replacing rubber over the whole outer surface of the tyre. Manufacturing a retread tyre for an average car takes 4.5 gallons less oil than the equivalent new tyre and for commercial vehicle tyres the saving is estimated to be about 15 gallons per tyre. Car tyres can only be retreaded once but truck tyres can be retreaded up to three times.
Recycling through grinding
Grinding is the most widespread materials recovery process in the UK. In 1999 it is estimated that 83,000 tonnes of tyre were granulated. This process produces a range of crumb sizes through the progressive size reduction process with the energy used to break up tyres increasing as the particle size decreases. Crumb is used in sports and play surfaces, brake linings, landscaping mulch, carpet underlay, absorbents for wastes and shoe soles. Crumb can also be recycled in road asphalt. Rubberised asphalt can increase road elasticity, temperature range and resistance to oxidation, which can result in fewer ruts, potholes and cracks in the surface. In 2000 a crumb road was laid near Battle in East Sussex. Some crumb can be used in formulations with virgin rubber, but this is less than 5% of the total. Salford University in conjunction with Pirelli and Corus has produced a crumb 0.4mm in diameter, small enough to be recycled in tyres. Pirelli plans to increase the 5% rubber crumb content currently used in manufacture to 20% in 2006. Corus hopes to use the steel innards for smelting.
Recycling through cryogenic fragmentation
During cryogenic fragmentation, tyres are shredded and cooled to below minus 80 degrees C. A hammer mill then pounds the chips to separate the components. The resultant rubber granules can be used for athletics tracks, carpet underlay, playground surfaces and rubberised asphalt for road surfaces. The energy input required for such low temperatures is relatively high.
Recycling through de-vulcanisation
Treating vulcanised rubber with heat or chemicals can produce devulcanised rubber, which can be used to replace part of the virgin material in automotive and cycle tyres, conveyor belts and footwear. The variety of uses for this rubber has been limited due to its unreactive nature leading to poor bonding/strength. However Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) has recently developed a process that alters the molecular bonding properties of the rubber and produces a material similar to PVC with a 50% recycled rubber content. Possible uses are for automotive components, building products, coatings, sealants and containers for hazardous waste. The developers believe it provides a valuable option for waste tyres.
Recycling through microwave technology
Advance Molecular Agitation Technology (AMAT) have developed a prototype using microwave technology. This breaks the tyres into their original components. The steel is of grade A quality and can therefore be sold for recovery, the carbon and oil are also reusable. The amount of emissions produced are minimal. The first commercial scale prototype has a capacity of 2,000 tonnes of tyres a year.
Energy Recovery
Tyres have a high calorific value, about 20% greater than that of coal, which on burning can be harnessed to produce energy.
Energy Recovery through pyrolysis
Compared to recovery of energy by direct burning, pyrolysis is a self-contained process, which avoids the release of large volumes of combustion gases. This saves on the cost of cleaning or "scrubbing" systems needed with normal incineration to remove pollutants from the gases. It also means that the process can be controlled to recover products for resale.
Energy Recovery through incineration in cement kilns
Tyres are able to replace up to about 25% of the coal which would otherwise be used in cement kilns, and reduce nitrogen oxide emissions. Cement kilns could provide a recovery option for up to half of the UK's total waste tyre arisings. The Used Tyre Working Group (UTWG) believe this recovery route will be key to achieving 100% tyre recovery by 2006. There is however some concern regarding dioxins, particulates and other airborne pollutants that are produced by these kilns.
Other uses of waste tyres
Other uses account for about 20,000 tonnes of waste arising. These include:
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boat and dock fenders
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under road surfaces
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sports tracks
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weights on silage sheeting on farms
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crash barriers at motor racing circuits
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children's play surfaces and furniture
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protection for young plants and trees
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compost heap containers
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roof tiles
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noise control products
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structural support for earth walls
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motorway embankments
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artificial reefs and coastal defences
The European Union End-of Life Vehicles (ELV) Directive
The End-of-Life Vehicles Directive (2000/53/EC) came into force on 21 October 2000 and Member States should have enacted legislation to comply with the Directive by 21 April 2002. The Directive will require EU Member States (including the UK) to:
- Ensure that all ELVs are only treated by authorised dismantlers
- Provide free take-back of all ELVs for new vehicles put on the market after 2002; from 2007 provide free take-back for all vehicles including those put on market before 2002
- Restrict the use of heavy metals in vehicles from July 2003
- Ensure that a minimum of 85% of vehicles are reused or recovered (including energy recovery) and at least 80% must be reused or recycled from 2006, increasing to a 95% reused or recovered (including energy recovery) and 85% reused or recycled by 2015
It also requires the 'de-pollution' of vehicles before being recycled. This involves extracting petrol, diesel, brake fluid, engine oil, antifreeze, batteries, airbags, mercury-bearing components and catalysts.
Improvements required
Some of the areas that will require improvements in order to meet the 85% recycling rate include:
- Increased plastics recovery through better separation processes
- Development of applications/markets for recycled plastics
- Increased recovery of fluids
- Improved tyre recovery processes
- Initiation of other rubber recovery processes
- Reduction of residual metallic content of shredder residue
- Initiation of glass recovery processes
- Development of energy recovery processes for automotive shredder residues (ASR)
- Development post-shredder material recovery processes
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