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Pooja Dange

Electronic waste



E-waste is a term used to cover almost all types of electrical and electronic equipment (EEE) that has or could enter the waste stream. Although e-waste is a general term, it can be considered to cover TVs, computers, mobile phones, white goods (e.g. fridges, washing machines, dryers etc), home entertainment and stereo systems, toys, toasters, kettles – almost any household or business item with circuitry or electrical components with power or battery supply.

Why is e-waste growing?
E-waste is growing exponentially simply because the markets in which these products are produced are also growing rapidly as many parts of the world cross over to the other side of the ‘Digital Divide’. For example, between 2000 and 2005, the Organization for Economic Co-operation and Development (OECD) notes a 22% growth in Information and Communications Technology (ICT) in China. Furthermore, China was the 6th largest ICT market in 2006, after the US, Japan, Germany, UK and France. This is astounding when one considers that just ten years ago, under 1% of China’s population owned a computer
Computers are only one part of the e-waste stream though, as we see that in the EU in 2005, fridges and other cooling and freezing appliances, combined with large household appliances, accounted for 44% of total e-waste; according to UNU’s Study supporting the 2008 Review of the Waste Electrical and Electronic Equipment (WEEE) Directive.
Rapid product innovations and replacement, especially in ICT and office equipment, combined with the migration from analogue to digital technologies and to flat-screen TVs and monitors, for example, are fuelling the increase. Additionally, economies of scale have given way to lower prices for many electrical goods, which has increased global demand for many products that eventually end up as e-waste.

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Why is e-waste different from general municipal waste?
In addition to various hazardous materials, e-waste also contains many valuable and precious materials. In fact up to 60 elements from the periodic table can be found in complex electronics. Using the personal computer (PC) as an example – a normal Cathode Ray Tube (CRT) computer monitor contains many valuable but also many toxic substances. One of these toxic substances is cadmium (Cd), which is used in rechargeable computer batteries and contacts and switches in older CRT monitors.
Cadmium can bio-accumulate in the environment and is extremely toxic to humans, in particular adversely affecting kidneys and bones . It is also one of the six toxic substances that has been banned in the European Restriction on Hazardous Substances (RoHS) Directive. Beyond CRT monitors, plastics, including polyvinyl chloride (PVC) cabling is used for printed circuit boards, connectors, plastic covers and cables.
When burnt or land-filled, these PVCs release dioxins that have harmful effects on human reproductive and immune systems . Mercury (Hg), which is used in lighting devices in flat screen displays, can cause damage to the nervous system, kidneys and brain, and can even be passed on to infants through breast milk .
Electrical goods contain a range of other toxic substances such as lead (Pb), beryllium (Be), brominated flame retardants and polychlorinated biphenyls(PCB) just to name a few. Lead plays an important role in the overall metal production processes and while attempts to design-out lead from EEE does not necessarily mean that it is no longer used. Even the lead-free solder elements are co-produced with lead. This illustrates the need for a holistic view to be taken in analyzing the e-waste situation for working out possible solutions.

On the other hand, the huge impact of EEE on valuable metals resources must not be neglected. A mobile phone e.g. can contain over 40 elements including base metals (copper (Cu), tin (Sn),..), special metals (cobalt (Co), indium (In), antimony (Sb), and precious metals (silver (Ag), gold (Au), palladium (Pd), ..). The most common metal is copper (9 g), while the precious metal content is in the order of milligrams only: 250 mg silver, 24 mg gold and 9 mg palladium. Furthermore, the lithium-ion battery contains about 3.5 grams of cobalt. This appears to be quite marginal but with the leverage of 1.2 billion mobile phones sold globally in 2007 this leads to a significant metal demand .
Similar calculations can be made for computers or other complex electronics and the increasing functionality of EEE products is largely achieved using the unique properties of precious and special metals. For example 80% of the world indium demand is used for LCD screens, over 80% of ruthenium is used for hard disks and 50% of the worldwide demand for antimony is used for flame retardants. Taking into account the highly dynamic growth rates of EEE, it becomes clear that they are a major driver for the development of demand and prices of certain metals.

Because of this complex composition of valuable and hazardous substances, specialized, often “high-tech” methods are required to process e-waste in ways that maximize resource recovery and minimize potential harm to humans or the environment. Unfortunately, the use of the these specialized methods is rare, with much of the world’s e-waste traveling great distances, mostly to developing countries, where crude techniques are often used to extract precious materials or recycle parts for further use. These “backyard” techniques pose dangers to poorly protected workers and their local natural environment.
Moreover, they are very inefficient in terms of resource recovery as recycling in these instances usually focuses on a few valuable elements like gold and copper (with often poor recycling yields), while most other metals are discarded and inevitably lost. In this sense it can be demonstrated that resource efficiency is another important dimension in the e-waste discussion in addition to the ecological, human security.

E-waste management

Today the electronic waste recycling business is in all areas of the developed world a large and rapidly consolidating business. People tend to forget that properly disposing or reusing electronics can help prevent health problems, create jobs, and reduce greenhouse-gas emissions. Part of this evolution has involved greater diversion of electronic waste from energy-intensive down cycling processes (e.g., conventional recycling), where equipment is reverted to a raw material form. This recycling is done by sorting, dismantling, and recovery of valuable materials. This diversion is achieved through reuse and refurbishing. The environmental and social benefits of reuse include diminished demand for new products and virgin raw materials (with their own environmental issues); larger quantities of pure water and electricity for associated manufacturing; less packaging per unit; availability of technology to wider swaths of society due to greater affordability of products; and diminished use of landfills.
Audiovisual components, televisions, VCRs, stereo equipment, mobile phones, other handheld devices, and computer components contain valuable elements and substances suitable for reclamation, including lead, copper, and gold.
One of the major challenges is recycling the printed circuit boards from the electronic wastes. The circuit boards contain such precious metals as gold, silver, platinum, etc. and such base metals as copper, iron, aluminum, etc. One way e-waste is processed is by melting circuit boards, burning cable sheathing to recover copper wire and open- pit acid leaching for separating metals of value. Conventional method employed is mechanical shredding and separation but the recycling efficiency is low. Alternative methods such as cryogenic decomposition have been studied for printed circuit board recycling, and some other methods are still under investigation.                                    

Processing techniques

In many developed countries, electronic waste processing usually first involves dismantling the equipment into various parts (metal frames, power supplies, circuit boards, plastics), often by hand, but increasingly by automated shredding equipment. A typical example is the NADIN electronic waste processing plant in Novi Iskar, Bulgaria—the largest facility of its kind in Eastern Europe. The advantages of this process are the humans ability to recognize and save working and repairable parts, including chips, transistors, RAM, etc. The disadvantage is that the labor is cheapest in countries with the lowest health and safety standards.
In an alternative bulk system, a hopper conveys material for shredding into an unsophisticated mechanical separator, with screening and granulating machines to separate constituent metal and plastic fractions, which are sold to smelters or plastics recyclers. Such recycling machinery is enclosed and employs a dust collection system. Some of the emissions are caught by scrubbers and screens. Magnets, eddy currents, and trommel screens are employed to separate glass, plastic, and ferrous and nonferrous metals, which can then be further separated at a smelter.
Leaded glass from CRTs is reused in car batteries, ammunition, and lead wheel weights, or sold to foundries as a fluxing agent in processing raw lead ore. Copper, gold, palladium, silver and tin are valuable metals sold to smelters for recycling. Hazardous smoke and gases are captured, contained and treated to mitigate environmental threat. These methods allow for safe reclamation of all valuable computer construction materials. Hewlett-Packard product recycling solutions manager Renee St. Denis describes its process as: "We move them through giant shredders about 30 feet tall and it shreds everything into pieces about the size of a quarter. Once your disk drive is shredded into pieces about this big, its hard to get the data off".
An ideal electronic waste recycling plant combines dismantling for component recovery with increased cost-effective processing of bulk electronic waste.
Reuse is an alternative option to recycling because it extends the lifespan of a device. Devices still need eventual recycling, but by allowing others to purchase used electronics, recycling can be postponed and value gained from device use.    

Benefits of recycling   

Recycling raw materials from end-of-life electronics is the most effective solution to the growing e-waste problem. Most electronic devices contain a variety of materials, including metals that can be recovered for future uses. By dismantling and providing reuse possibilities, intact natural resources are conserved and air and water pollution caused by hazardous disposal is avoided. Additionally, recycling reduces the amount of greenhouse gas emissions caused by the manufacturing of new products.
Benefits of recycling are extended when responsible recycling methods are used. In the U.S., responsible recycling aims to minimize the dangers to human health and the environment that disposed and dismantled electronics can create. Responsible recycling ensures best management practices of the electronics being recycled, worker health and safety, and consideration for the environment locally and abroad.