Recycling scrapped cars plays an important role in reducing
pollution by decreasing the amount of waste that ends up in
landfill.
A new study has investigated advanced technologies to increase
the recovery rate from end-of-life vehicles (ELVs), which
can help EU Member States achieve EU targets for resource
and energy recovery.
Approximately 9 million ELVs are scrapped every year in the
EU and recycling plays an important part of the waste disposal
process. Cars are primarily composed of metal (about 75 per
cent) and a range of other materials. Currently, the metal
components can be separated and completely recycled, but this
leaves a mainly organic residue, which is disposed of in landfills
or incinerated.
ELVs are collected and dismantled to remove the battery,
tyres, fluids and any parts that can be re-used, after which
the wreck is shredded. The metallic parts are separated by
physical processes and recovered as ferrous scrap (iron and
steel - comprising 70 per cent of the total vehicle waste)
and nonferrous metals (5 per cent) - all of which is recycled.
The 25 per cent remainder is the automotive shredder residue
(ASR), which is composed mainly of plastics, contaminated
with any metallic and other parts that could not be separated.
This is often disposed of in landfills as solid urban waste
and is not recycled.
The study suggests that recovery rates for ELVs set in the
EU
Directive on end-of life vehicles will not be met
until the volume of the ASR is further reduced. Treatment
of the ASR, therefore, focuses on recovering any useable materials,
reducing the volume of the ASR to cut down on the quantity
that will end up in landfill and recovering the energy from
the petrochemical content of the plastics.
Three advanced methods of treating ASR were examined - incineration,
pyrolysis and gasification. Public concerns about emissions
produced from incinerating or burning the ASR meant this method
was considered less environmentally friendly than pyrolysis.
No disadvantages were found using pyrolysis - where heat was
used to break down the organic material in the absence of
oxygen.
Treatment of the ASR by pyrolysis yielded ferrous and nonferrous
metal contaminants - which could be recovered and recycled
- and oil which could be used as a secondary fuel. It also
produced recoverable gas which could be reused as an energy
source and a small volume of solid residue which would be
disposed of in landfill.
Gasification was also considered a better option for treatment
of the ASR than incineration, because the process produced
fewer emissions. It also produced gas which could be used
as a fuel source and residues that could be used in the construction
industries.
Manufacturers are advised that incorporating end-of-life
management principles into the early design and development
stages of vehicle production, can ensure maximum recycling
when the vehicles reach end-of-life stage.
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