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
- Cell phones
- 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.
A traffic signal employing LEDs. Image Source: Unisouth on https://en.wikipedia.org/wiki/Traffic_light#/media/File:Modern_British_LED_Traffic_Light.jpg
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 and Further Reading