By Gary Thomas
Contents
Introduction to
LEDs
Properties
and Applications of LEDs
Recycling of LEDs
The
Environmental Benefits of Recycling LEDs
Sources
Introduction
to LEDs
LED is an acronym that stands for light-emitting diodes. First
used in 1968, LEDs are semiconductors which emit light via
electroluminescence (electrons jumping across energy gaps and emitting
photons). LEDs are a common light source in many sectors and in recent
years there has been a major shift towards the wholesale use of LEDs
over conventional, incandescent light bulbs. This is beneficial to the
environment, but there is still an important need to recycle these
bulbs to ensure sustainable living.
Properties
and Applications of LEDs
LED lighting is a popular alternative to conventional
lightbulbs for several reasons. Firstly, they usually last a lot long
longer than conventional bulbs, with an average lifespan of around 50
000 hours compared to incandescent bulbs that last for around 1200
hours.
They also use less electricity and also emit more light than
traditional bulbs on a pound-for-pound basis. This has made LED lights
popular with both the cost-conscious and advocates of clean technology.
Furthermore, LEDs do not contain any mercury (an element which
is famously environmentally hazardous), as is the case with CFL lights
(compact fluorescents).
LEDs are also very durable, and can handle more wear and tear
than conventional light bulbs. They are not climate-dependant either,
i.e. humidity and low temperatures have no effect on the performance of
the bulb which is not the case for some alternatives.
Also importantly from an environmental standpoint, carbon
dioxide emissions related to an LED lightbulb are only around 10% of
those related to a traditional bulb.
LEDs lights increasingly have a wide range of lighting
applications, including:
- TV screens
- Laboratory equipment
- Radios
- Cell phones
- Watches
- Calculators
- Household lighting
- Retail illumination
- Traffic signals
- Car brake lights
These are but a few of the disparate applications of LEDs and
more applications are found daily as LEDs continue to take over from
tungsten filament bulbs.
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A traffic signal employing
LEDs. Image Source: http://www6.montgomerycountymd.gov
Recycling
of LEDs
LEDs are environmentally friendly during their lifespan, but
can be even more beneficial to the environment if recycled. Over 95% of
an LED bulb is recyclable and there are waste management companies that
will collect and recycle LEDs for a small fee.
As LEDs do not contain significant amounts of any harmful
components, they are classed as RoHS compliant. RoHS stands for the
Restriction of the Use of Certain Hazardous Substances in Electrical
and Electronic Equipment, which came into effect in the UK on 1st
July 2006. These restrictions prevent the sale of equipment containing
harmful levels of mercury, lead, cadmium, PBB, PBDE and hexavalent
chromium. Due to this compliance, LEDs can be disposed of and recycled
in the same way as an ordinary light bulb.
The recycling process generally involves the LED bulbs being
crushed and separated, using a bar screen, into constituent components.
From here, the glass is passed through a magnetic field that can remove
any ferrous metal present. To remove the aluminium and lead that is
present in LED lights, a non-ferrrous metal separator blasts airs at
the crushed glass to direct the metal down a separate chute. The glass
can then be used in other products, as can the aluminium. As glass does
not degrade during recycling, it can be recycled many times over.
In the UK, LED lighting falls under the WEEE directive, which
governs how certain products are disposed of at the end-of-life stage.
WEEE stands for Waste Electrical and Electronic Equipment, and
encourages recycling by setting a target amount of electrical and
electronic equipment that must be recycled. Recently the Environmental
Agency has made changes to WEEE regulations and LED companies will need
to make sure that they are part of a compliance scheme, an example of
which is Recolight. Under the new changes, people should check that a
lighting producer is not trying to pass on recycling costs under the
WEEE regulation 9.2.
The
Environmental Benefits of Recycling LEDs
Though LED lights have environmentally-friendly properties
during their life-span, it is important that they are recycled
correctly, as there are suggestions that they contain relatively high
amounts of elements which can be damaging to the environment.
A recent study by researchers at the University of California
found that most LED lights contain a high proportion of nickel, and
coloured LED bulbs contain large amounts of lead. On top of this, trace
amounts of arsenic are also present. Not only can these elements be
damaging to the environment, but they can also cause health problems.
Though overall LED lights are more environmentally-friendly than
conventional, incandescent bulbs it is still important that LEDs are
not simply dumped into landfills, as this could have long-term
environmental effects.
LEDs also contain large amounts of aluminium which can cause a
greater impact on landfills in comparison to other lighting systems,
mainly due to the energy and resources used at the manufacturing stage.
Given the huge rise in demand in recent years for LED lights
and the dearth in the natural resources that are used to produce them,
it is important that recycling of LEDs begins sooner rather than later
so that LEDs can continue to be used well into the future.
Sources
Lim,S,R. et al. Potential Environmental Impacts of
Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity, and
Hazardous Waste Classification. Environ. Sci. Technol.,
2011, 45 (1), pp 320–327
http://www.designrecycleinc.com
http://businessrecycling.com.au/recycle/led-lights
http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/2012_led_lca-pt2.pdf
http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/2012_LED_Lifecycle_Report.pdf
http://www.myledlightingguide.com/FAQ.aspx
http://www.bis.gov.uk/nmo/enforcement/rohs-home
http://ledsmagazine.com/news/9/2/29
http://www.environment-agency.gov.uk/business/topics/waste/32084.aspx