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Electronic Waste |
Electronic Waste (e-waste): Reduce, Reuse and Recycle
Background
Rapid
developments in technology lead to increase in diversified production of
electrical and electronic items. With increasing population the consumption of
such kind of items are also increasing rapidly. Waste electrical and electronic
equipment or e-waste is the waste after the product’s end of life or when the
product is outdated on technological front. Electrical and electronic
equipments have its significant impact in various fields in our society due to
its higher capabilities, minimum error, and quite faster in operations. Massive
use of computer, laptops, cellular phone, television, etc causes the generation
of large quantity of e-waste which is a major global problem today. Especially
rapid growth of computing and mobile phones is driving the e-waste production. E-waste
is considered as one of the fastest growing solid waste streams in the world. Continuous
generation of e-waste causes serious environmental problems when it is disposed
in land-fills because of its hazardous content. There is risk to human health
and animals due to the excessive exposure of toxic chemicals derive from
e-waste. Therefore it is a big challenge for developing countries in the management
of electronic waste. Figure 1 is showing a schematic view of sources, effects
in environment and human being or animal, and possible ways of management of
the e-waste.
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| Figure 1. A schematic form of sources, effects on environment, human beings or animals, and management of the e-waste |
Current scenario and future of e-waste production
At the present
scenario due to the inadequate recycling infrastructure only about 20% of the
total e-waste is possible to recycle, whereas 80% either ending up in land
filling or being informally recycled. Today maximum e-wastes are generating
from waste mobile phones and computer parts. Quantitatively it will not be
surprised if we say that the existence of number of mobile phones is more than the number of people living on
the earth at present. The global production of e-waste is increasing
exponentially and is expected to accelerate in the near future.
Further,
due to the rapid up-gradation and renovation leads to the shortening of life
cycle of various electronic devices like mobile, television, laptops etc. Which
substantially increase the waste electrical and electronic equipments. India
has emerged as fifth biggest producer of e-waste in the world now. According to
the reported literature the generation of e-waste is growing at a rate of 15%
annually. In the next few years billions of computers, mobiles and other
electronic gadgets will be retired. This will be the major sources of the
e-waste in the coming years.
Problem because of e-waste
Inappropriate
handling of e-waste causes contamination of various toxic elements in the
environment, which could cause risk to human health, animals and environment.
E-waste contains various toxic metals such as lead (Pb), cadmium (Cd), mercury (Hg),
chromium (Cr), arsenic (As), nickel (Ni), selenium (Se), lithium (Li), zinc (Zn),
etc. Due to the exposures of this toxic element derive from e-waste proves to
be harmful to the workers in the region of e-waste extraction and also the
population in that region. The health hazards include respiratory problems,
reproductive disorders, metabolic disorders, and cancers. Women and children
have adverse health burden due to the excessive exposure of the toxic compounds
generated from e-waste. Contaminants of inorganic (lead, cadmium, arsenic,
gallium, and indium) and organic (solvents, fire retardants, and plasticizers)
chemicals in the soil and water may interact with each other, which leads to
the formation of more dangerous compounds. In the last few decades a major part
of e-waste has been ether landfills or incinerate. But due to the release of
toxic chemicals it proves to be dangerous for ecosystem. There is negative
influence on crop plants, birds, eggs, edible tissues of chickens and soil
microbiological communities.
Disposal and recycling
E-waste is quite
different from the other forms of municipal or industrial waste by physically as
well as chemically. So, special measure should be taken in handling and
recycling of the e-waste to avoid environmental pollution and harmful effects
on human beings and animals. On the basis of chemical composition, the e-waste
consists of various metals, metalloids, precious metals, halogenated compounds
and radioactive elements. Metals and metalloids include aluminium, arsenic,
antimony, barium, beryllium, cadmium, chromium, copper, europium, lead,
lithium, iron, manganese, mercury, nickel, selenium, silica, tin, yttrium,
zinc, etc. Precious metals include gold, indium, silver, palladium, platinum,
etc. There is a research scope in this area where the valuable materials
(copper, gold, platinum) can be recovered from the e-waste. Some important
materials such as copper, gold, platinum, aluminium, palladium, nickel, zinc,
and so on are present in the e-waste in different percentage. Recovery of this
material from e-waste may be good initiative in the reduction of the e-waste
along with the reduction of environmental pollution. Recycling has always a
lower ecological impact than land filling of incinerated e-waste. This process
can recover significant amount of useful materials from e-waste.
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| Figure 2. A layout for recycling of e-waste |
Hybrid
technology: Instead of using any one pathway of
leaching, we can combine chemical and biological leaching.
Leaching
by supercritical fluid: Here the metals are leached in
presence of super critical fluid with hydrogen peroxide and sulphuric acid as
co-solvent.
Super
gravity separation: Metal and alloy of different melting
point which can be easily separated by creating super gravity field. The field
is created by centrifugal apparatus.
Electrochemical
process: It is a one step recovery process of metals. Here,
the metals are recovered by combining electrochemical dissolution and
deposition.
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