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RISHIRAJ INSTETUET OF TECHNOLOGY, INDOREREVTI GRAM, SAWER ROAD, INDORE-453331
MINNOR PROJECT ON
E-WASTE RECYCLING MANAGEMENTSSESSION 2009-2010
MECHANICAL ENGINEERING2006-2010RAJIVE GANDHI PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL
GUIDED BY SUBMITTED BY
H.O.D. S. B. DIGHE NITIN SINGHLECTURER R. MEHTA
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CONTENT
1.0. ABSTRAC
2.0. INTRODUCTION
3.0. DEFINITION
4.0. DESTINATION OF E-WASTE
5.0. INDIAN SCENARIO
6.0. THE STATUS
7.0. BASEL CONVENTION
8.0. E-TOXICS IN E-WASTE
8.1. E-WASTE AND ITS EFFECT ON HEALTH AND THE ENVIRONMENT
9.0. LIFE CYCLE OF E-WASTE
10.0. MANAGEMENT OF E-WASTES
10.1. INVENTORY MANAGEMENT
10.2. PRODUCTION-PROCESS MODIFICATION
10.3. VOLUME REDUCTION
10.4. RECOVERY AND REUSE
10.5. SUSTAINABLE PRODUCT DESIGN
11.0. WASTE MANAGEMENT CONCEPTS
11.1. RESOURCE RECOVERY
11.2. RECYCLING
11.3. WASTE MANAGEMENT TECHNIQUES
11.3.1. LANDFILL
11.3.2. INCINERATION
11.3.3. COMPOSTING AND ANAEROBIC DIGESTION
11.3.4. MECHANICAL BIOLOGICAL TREATMENT
11.3.5. PYROLYSIS & GASIFICATION
12.0. RECYCLING OF E-WASTE
12.1. RECYCLING/RECOVERY SYSTEM
12.2. BIFURCATION OF ELECTRONIC SCRAP
12.2.1. PRINTED CIRCUIT BOARDS (PCBS)
12.2.2. CHARACTERISTICS OF PCB SCRAP
12.2.3. DENSITY DIFFERENCES
12.2.4. MAGNETIC AND ELECTRICAL CONDUCTIVITY DIFFERENCES
12.2.5. POLYFORMITY
12.2.6. LIBERATION SIZE
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12.2.7. CHEMICAL REACTIVITY
12.2.8. ELECTROPOSITIVITY
12.3. DISASSEMBLY
12.4. MECHANICAL/PHYSICAL RECYCLING PROCESS
12.5. MECHANICAL APPROACHES OF RECYCLING ELECTRONIC SCRAP
12.6. HYDROMETALLURGICAL APPROACHES
12.7. EXTRACTION OF IC/ OTHER COMPONENTS FROM PCB
12.7.1. RECOVERY OF GOLD
12.7.2. MONITORS
12.7.2.1. Recovery of Glass from CRT
12.7.2.2. Yoke Core, Metallic Core and Copper from Transformers
12.7.2.3. Copper Extraction from Wires
12.7.2.4. Manual drawing of Wires for Copper
12.7.2.5. Plast ic Shredding and Graining
12.7.2.6. Dismantling of compressor & segregation of compressor & cooling box
12.8. DISPOSAL
12.9. ADVANTAGES OF RECYCLING E-WASTE
13.0. RESPONSIBILITIES OF GOVERNMENT, INDUSTRIES, AND CITIZEN
13.1. RESPONSIBILITIES OF THE GOVERNMENT
13.2. RESPONSIBILITY AND ROLE OF INDUSTRIES
13.3. RESPONSIBILITIES OF THE CITIZEN
14.0. E-WASTE POLICY FOR INDIA
15.0. CONCLUSION
16.0. REFERENCES
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1.0. ABSTRACT
The production of electric and electronic equipment (EEE) is one of the fastest growing areas.This
development has resulted in an increase of waste electric and electronic equipment (WEEE).In view
of the environmental problems involved in the management of WEEE, many counties and
organizations have drafted national legislation to improve the reuse, recycling and other forms of
recovery of such wastes so as to reduce disposal. Recycling of WEEE is an important subject not
only from the point of waste treatment but also from the recovery of valuable materials.
"E-waste" is a popular, informal name for electronic products nearing the end of their "useful life.
"E-wastes are considered dangerous, as certain components of some electronic products contain
materials that are hazardous, depending on their condition and density. The hazardous content of
these materials pose a threat to human health and environment. Discarded computers, televisions,
VCRs, stereos, copiers, fax machines, electric lamps, cell phones, audio equipment and batteries if
improperly disposed can leach lead and other substances into soil and groundwater. Many of these
products can be reused, refurbished, or recycled in an environmentally sound manner so that they are
less harmful to the ecosystem. This paper highlights the hazards of e-wastes, the need for its
appropriate management and options that can be implemented.
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2.0. INTRODUCTION
Industrial revolution followed by the advances in information technology during the last century has
radically changed people's lifestyle. Although this development has helped the human race,
mismanagement has led to new problems of contamination and pollution. The technical prowess
acquired during the last century has posed a new challenge in the management of wastes. For
example, personal computers (PCs) contain certain components, which are highly toxic, such as
chlorinated and brominated substances, toxic gases, toxic metals, biologically active materials, acids,
plastics and plastic additives. The hazardous content of these materials pose an environmental and
health threat. Thus proper management is necessary while disposing or recycling ewastes.
These days computer has become most common and widely used gadget in all kinds of activities
ranging from schools, residences, offices to manufacturing industries. E-toxic components in
computers could be summarized as circuit boards containing heavy metals like lead & cadmium;
batteries containing cadmium; cathode ray tubes with lead oxide & barium; brominates flame
retardants used on printed circuit boards, cables and plastic casing; poly vinyl chloride (PVC) coated
copper cables and plastic computer casings that release highly toxic dioxins & furans when burnt to
recover valuable metals; mercury switches; mercury in flat screens; poly chlorinated biphenyl's
(PCB's) present in older capacitors; transformers; etc. Basel Action Network (BAN) estimates that
the 500 million computers in the world contain 2.87 billion kg of plastics, 716.7 million kg of lead
and 286,700 kg of mercury. The average 14-inch monitor uses a tube that contains an estimated 2.5
to 4 kg of lead. The lead can seep into the ground water from landfills thereby contaminating it. If
the tube is crushed and burned, it emits toxic fumes into the air.
Long-term exposure to deadly component chemicals and metals like lead, cadmium, chromium,
mercury and polyvinyl chlorides (PVC) can severely damage the nervous systems, kidneys and
bones, and the reproductive and endocrine systems, and some of them are carcinogenic and
neurotoxin. It is a generic term used to describe old, end-of-life electronic appliances such as
computers, laptops, TVs, DVD players, Mobile Phones, MP-3 players, etc., which have been
disposed of by their original users. Though there is no generally accepted definition of E-waste, in
most cases, E-waste comprises of relatively expensive and essentially durable products used for data
processing, tile-communications or entertainment in private house-holds and businesses.
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Public perception of E-waste is often restricted to a narrower sense, comprising mainly of end-of life
information and tile-communication equipment, and consumer electronics. However, technically
speaking, electronic waste is only a sub-set of WEEE (Waste Electrical & Electronic
Equipment). According to the Organization for Economic Cooperation & Development
(OECD), any appliance using an electric power supply that has reached its end-of-life would come
under WEEE. At macro-level, there are two ways to handle the E-Wastes: Disposal or Recycle /
Refurbish.
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3.0.DEFINITION
Electronic waste includes computers, entertainment electronics, mobile phones and Other items that
have been discarded by their original users. While there is no Generally accepted definition of
electronic waste, in most cases electronic waste Consists of electronic products that were used for
data processing, Telecommunications or entertainment in private households and businesses that are
now considered obsolete, broken, or un-repairable. Despite its common classification
as a waste, disposed electronics are a considerable category of secondary resource due to their
significant suitability for direct reuse, refurbishing, and material recycling of its constituent raw
materials. Re-conceptualization of electronic waste as a resource thus preempts its potentially
hazardous qualities.
Definition of electronic waste according to the WEEE directive :
Large household appliances (ovens, refrigerators etc.)
Small household appliances (toasters, vacuum cleaners etc.)
Office & communication (PCs, printers, phones, faxes etc.)
Entertainment electronics (TVs, HiFis, portable CD players etc.)
Lighting equipment (mainly fluorescent tubes)
E-tools (drilling machines, electric lawnmowers etc.)
Sports & leisure equipment (electronic toys, training machines etc.)
Medical appliances and instruments
Surveillance equipment
Automatic issuing systems (ticket issuing machines etc.)
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4.0. DESTINATION OF E-WASTE:
The waste is imported by over 35 countries, which include India, China, Pakistan, and Malaysia etc.
Fig. 1 shows the global E-waste traffic routes across Asia. The waste generated by the consumers of
electronic goods gets collected by scavengers or garbage collectors, and usually gets deported to
backyard stripping houses etc, where the potentially valuable substances are separated from the
waste and the residue, which may still contain many hazardous (or useful) substances, is dumped or
incinerated.
Fig-1 Asian E-Waste Traffic
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5.0. INDIAN SCENARIO
There is an estimate that the total obsolete computers originating from government offices, business
houses, industries and household is of the order of 2 million nos. Manufactures and assemblers in a
single calendar year, estimated to produce around 1200 tons of electronic scrap. It should be noted
that obsolesce rate of personal computers (PC) is one in every two years. The consumers finds it
convenient to buy a new computer rather than upgrade the old one due to the changing
configuration, technology and the attractive offers of the manufacturers. Due to the lack of
governmental legislations on e-waste, standards for disposal, proper mechanism for handling these
toxic hi-tech products, mostly end up in landfills or partly recycled in a unhygienic conditions and
partly thrown into waste streams. Computer waste is generated from the individual households; the
government, public and private sectors; computer retailers; manufacturers; foreign embassies;
secondary markets of old PCs. Of these, the biggest source of PC scrap are foreign countries that
export huge computer waste in the form of reusable components.
Electronic waste or e-waste is one of the rapidly growing environmental problems of the world. In
India, the electronic waste management assumes greater significance not only due to the generation
of our own waste but also dumping of e-waste particularly computer waste from the developed
countries.
With extensively using computers and electronic equipments and people dumping old electronic
goods for new ones, the amount of E-Waste generated has been steadily increasing. At present
Bangalore alone generates about 8000 tonnes of computer waste annually and in the absence of
proper disposal, they find their way to scrap dealers.
E-Parisaraa, an eco-friendly recycling unit on the outskirts of Bangalore which is located in
Dobaspet industrial area, about 45 Km north of Bangalore, makes full use ofE-Waste. The plant
which is Indias first scientific e-waste recycling unit will reduce pollution, landfill waste and
recover valuable metals, plastics & glass from waste in an eco-friendly manner. E-Parisaraa has
developed a circuit to extend the life of tube lights. The circuit helps to extend the life of fluorescent
tubes by more than 2000 hours. If the circuits are used, tube lights can work on lower voltages. The
initiative is to aim at reducing the accumulation of used and discarded electronic and electrical
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equipments.
India as a developing country needs simpler, low cost technology keeping in view of maximum
resource recovery in an environmental friendly methodologies. E-Parisaraa, deals with practical
aspect ofe-waste processing as mentioned below by hand. Phosphor affects the display resolution
and luminance of the images that is seen in the monitor.
E-Parisaraas Director Mr. P. Parthasarathy, an IIT Madras graduate, and a former consultant for a
similar e-waste recycling unit in Singapore, has developed an eco-friendly methodology for reusing,
recycling and recovery of metals, glass & plastics with non-incineration methods . The hazardous
materials are segregated separately and send for secure land fill for ex.: phosphor coating, LEDs,
mercury etc.
We have the technology to recycle most of the e-waste and only less than one per cent of this will be
regarded as waste, which can go into secure landfill planned in the vicinity by the HAWA project.
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6.0. THE STATUS
The first comprehensive study to estimate the annual generation of E-waste in India and answer the
questions above is being undertaken up by the National WEEE Taskforce. The preliminary estimates
suggest that total WEEE generation in India is approximately 1,46,000 tonne per year. The top states
in order of highest contribution to WEEE include Maharashtra, Andhra Pradesh,Tamil Nadu, Uttar
Pradesh, West Bengal, Delhi, Karnataka, Gujarat, Madhya Pradesh and Punjab. The city-wise
ranking of largest WEEE generators is Mumbai, Delhi, Bangalore, Chennai, Kolkatta, Ahmedabad,
Hyderabad, Pune, Surat and Nagpur. An estimated 30,000 computers become obsolete every year
from the IT industry in Bangalore alone simply due to an extremely high obsolescence rate of 30 per
cent per annum.
Almost 50 per cent of the PCs sold in India are products from the secondary market and are re-
assembled on old components. The remaining market share is covered by multinational
manufacturers (30 per cent) and Indian brands (20 per cent). Three categories of WEEE account for
almost 90 per cent of the generation - Large Household Appliances, (42 per cent), Information &
Communications Technology Equipment, (34 per cent), Consumer Electronics, (14 per cent).
Over 2,000 trucks ferry E-waste in a clandestine manner and dump it in Delhi's scrap yards at
various locations, particularly Turkman Gate, Shastri Park, Loni, Seelampur and Mandoli. This
Ewaste primarily comes from Maharashtra, Tamil Nadu and Karnataka, and if Delhi were to protect
itself from such hazardous waste, then it would have to bring an effective legislation to prevent entry
of child labour into its collection, segregation and distribution. More than 6,000 children in the age
group of 10 to 15 years are engaged in various E-waste activities without adequate protection and
safeguards. They operate from various yards and recycling workshops.
Three States that send waste to Delhi generate over 25,000 tonne of E-waste through various
industrial activities. In a discreet arrangement with transporters, they dump around 50 per cent of it
at different places in Delhi. E-waste imported into Mumbai, Chennai, and Bangalore usually makes
its way to Delhi as there is a ready market for glass and plastic in the National Capital Region.
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In fact, waste from Mumbai constitutes a bulk of the 60 to 70 tones discarded electronics that land in
Delhi's scrap yards every day. It has also been estimated that Delhi alone gets 25 per cent of the E-
waste generated in the developed world which comes through cheaper imports. Such is the scale of
the menace that it has now acquired the dimension of an industry that employs nearly 30,000
workers in various scrap-yards and unauthorized recycling units.
The States sending Ewaste to Delhi should develop their own scrap-yards. Noting that the NCR has
over 40,000 industrial and medical units responsible for generating the waste, Delhi Government
should plant around 20 lakh saplings every year. Currently, a mere 5 per cent of E-waste recycled in
the country is recycled by the handful of formal recyclers and the rest is recycled by the informal
recyclers.
The E-waste recycled by the formal recyclers is done under environmentally sound practices which
ensure that damage is minimized to the environment. They also adopt processes so that the
workforce is not exposing to toxic and hazardous substances released during recycling process. But
they cannot match either the reach or the network of the informal recyclers used for sourcing of old
electrical and electronic items from business as well as individual households.
The items are collect, segregated and the informal recyclers further dismantle the ones that cannot be
sold as it is. The final step is recycling which is mainly manual using simple tools like hammer,
screw driver, etc., and by the use of rudimentary techniques like burning of wires in the
open, using acid bath for extraction of precious metals.
Furthermore, these activities are carried out without wearing any protective gear like masks, gloves,
etc. In the absence of suitable processes and protective measures, recycling E-waste results in toxic
emission to the air, water, soil and poses serious environmental and health hazards. Thus, the
challenges are manifold: environmental and health hazards; lack of awareness amongst various
stakeholders including public at large; investment required for setting up of state-of-the-art waste
management facilities; monitoring and reporting of the E-waste generated; and most importantly,
reconciling technological advancement with sustainable development.
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7.0. BASEL CONVENTION
The fundamental aims of the fundamental aims of the Basel Convention are the control and
reduction of trans-boundary movements of hazardous and other wastes including the prevention and
minimization of their generation, the environmentally sound management of such wastes and the
active promotion of the transfer and use of technologies.
A Draft Strategic Plan has been proposed for the implementation of the Basel Convention. The Draft
Strategic Plan takes into account existing regional plans, program or strategies, the decisions of the
Conference of the Parties and its subsidiary bodies, ongoing project activities and process of
international environmental governance and sustainable development. The Draft requires action at
all levels of society: training, information, communication, methodological tools, capacity building
with financial support, transfer of know-how, knowledge and sound, proven cleaner technologies
and processes to assist in the concrete implementation of the Basel Declaration. It also calls for the
effective involvement and coordination by all concerned stakeholders as essential for achieving the
aims of the Basel Declaration within the approach of common but differentiated responsibility.
Are the control and reduction of trans-boundary movements of hazardous and other wastes including
the prevention and minimization of their generation, the environmentally sound management of such
wastes and the active promotion of the transfer and use of technologies?
A set. of interrelated and mutually supportive strategies are proposed to support the concrete
implementation of the activities as indicated is described below:
1. To involve experts in designing communication tools for creating awareness at the highest
level to promote the aims of the Basel Declaration on environmentally sound management
and the ratification and implementation of the Basel Convention, its amendments and
protocol with the emphasis on the short-term activities.2. To engage and stimulate a group of interested parties to assist the secretariat in exploring
fund raising strategies including the preparation of projects and in making full use of
expertise in non-governmental organizations and other institutions in joint projects.
3. To motivate selective partners among various stakeholders to bring added value to making
progress in the short-term.
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4. To disseminate and make information easily accessible through the internet and other
electronic and printed materials on the transfer of know-how, in particular through Basel
Convention Regional Centers (BCRCs).
5. To undertake periodic review of activities in relation to the agreed indicators;
6. To collaborate with existing institutions and program to promote better use of cleaner
technology and its transfer, methodology, economic instruments or policy to facilitate or
support capacity-building for the environmentally sound management of hazardous and other
wastes.
The Basel Convention brought about a respite to the trans-boundary movement of hazardous waste.
India and other countries have ratified the convention. However United States (US) is not a party to
the ban and is responsible for disposing hazardous waste, such as, e-waste to Asian countries eventoday. Developed countries such as US should enforce stricter legislations in their own country for
the prevention of this horrifying act.
In the European Union where the annual quantity of electronic waste is likely to double in the next
12 years, the European Parliament recently passed legislation that will require manufacturers to take
back their electronic products when consumers discard them. This is called Extended Producer
Responsibility. It also mandates a timetable for phasing out most toxic substances in electronic
products.
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8.0. E-TOXICS IN E-WASTE
"Printed Circuit Boards contain heavy metals such as Antimony, Silver, Chromium, Zinc, Lead, Tin
and Copper. According to some estimates there is hardly any other product for which the sum of the
environmental impacts of raw material, extraction, industrial, refining and production, use anddisposal is as extensive as for printed circuit boards."
"In short, the product developers of electronic products are introducing chemicals on a scale which is
totally incompatible with the scant knowledge of their environmental or biological characteristics."
TABLE-1 Material used in a desktop computer and the efficiency of current
recycling processes
Name content (%
of total
weight)
Recycling
Efficiency %
Weight of
material (lb)
Use/Location
Plastics 22.9907 13.8 20 Includes organics,
oxides other than silicaLead 6.2988 3.8 5 Metal joining, radiation
shield/CRT, PWBAluminu
m
14.1723 8.5 80 Structural,
conductivity/housing,
CRT,PWB, connectors
Germani
um
0.0016 < 0.1 0 Semiconductor/PWB
Gallium 0.0013 < 0.1 0 Semiconductor/PWB
Iron 20.4712 12.3 80 Structural, magnetivity/
(steel) housing CRT,
PWBTin 1.0078 0.6 70 Metal joining/PWB, CRT
Copper 6.9287 4.2 90 Conductivity/CRT, PWB,
connectors
Barium 0.0315 < 0.1 0 In vacuum tube/CRTNickel 0.8503 0.51 80 Structural, magnetivity/
(steel) housing, CRT,
PWBZinc 2.2046 1.32 60 Battery, phosphor
emitter/PWB, CRTTantalu 0.0157 < 0.1 0 Capacitors/PWB, power
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m supply
Indium 0.0016 < 0.1 60 Transistor,
rectifiers/PWBVanadiu
m
0.0002 < 0.1 0 Red phosphor
emitter/CRTTerbium 0 0 0 Green phosphor
activator, dopant /CRT,
PWBBerylliu
m
0.0157 < 0.1 Thermal
conductivity/PWB,
connectorsGold 0.0016 < 0.1 99 Connectivity,
conductivity/PWB,
connectorsEuropiu
m
0.0002 < 0.1 0 Phosphor
activator/PWBTitaniu
m
0.0157 < 0.1 0 Pigment, alloying
agent/
(aluminum),housingRutheni
um
0.0016 < 0.1 80 Resistive circuit/PWB
Cobalt 0.0157 < 0.1 85 Structural,
magnetivity /(steel)
housing, CRT, PWBPalladiu
m
0.0003 < 0.1 95 Connectivity,
conductivity/PWB,
connectorsMangan
ese
0.0315 < 0.1 0 Structural, magnetivity/
(steel) housing, CRT,
PWBSilver 0.0189 < 0.1 98 Conductivity/PWB,
connectorsAntinom
y
0.0094 < 0.1 0 Diodes/housing, PWB,
CRTBismuth 0.0063 < 0.1 0 Wetting agent in thick
film/PWBChromiu
m
0.0063 < 0.1 0 Decorative, hardener/
(steel) housing
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Cadmiu
m
0.0094 < 0.1 0 Battery, glu-green
phosphor
emitter/housing, PWB,
CRT
Selenium
0.0016 0.00096 70 Rectifiers/PWB
Niobium 0.0002 < 0.1 0 welding allow/housing
Yttrium 0.0002 < 0.1 0 Red phosphor
emitter/CRTRhodiu
m
0 50 thick film
conductor/PWBPlatinu
m
0 95 Thick film
conductor/PWBMercury 0.0022 < 0.1 0 Batteries,
switches/housing, PWBArsenic 0.0013 < 0.1 0 Doping agents in
transistors/PWBSilica 24.8803 15 0 Glass, solid state
devices/CRT,PWB
8.1.E-waste and its effect on health and the environment
E-waste cannot be considered or treated like any kind of waste, because it contains hazardous and
toxic substances such as lead, mercury, cadmium or others such as dioxins and furans, bromined
flame retardants (produced when e-waste is incinerated). For instance, lead represents 6% of the total
weight of a computer monitor. Another example: nearly 36 chemical elements are
Incorporated in electronic equipment. This data further demonstrates the un-sustainability of
irresponsible electronic equipment disposal, its negative effect on the environment and the need to
implement management regulations which include actions like refurbishment and recycling.
Even though in the last years recycling has become a regular practice almost everywhere in the
world, some e-waste components present difficulties when they are recycled mainly because of their
complexity and the lack of methods. Such is the case of plastics used in electronic equipment which
contain flame retardants that impede the recycling process. In order to amplify the information
submitted in the web page We Re-cycle following is a more detailed description of electronic
equipment components effects on human health and the environment.
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Table-2Products and Health Effects of E-Waste
name of
chemicals
Characteristics Effects on Humans Impacts on the
EnvironmentPolychlorinate
d Biphenyl
(PCB)
Can be present in
condensers and
transformers of old
electronic
equipment because
of its properties as
cooler, lubricant
and its resistance
to high
temperatures.
Humans are exposed
through
contaminated food
consumption or
direct contact at
their workplace,
(e.g inadequate
disassembly of
electronic
equipment).
Exposure to this
compound can cause
anemia, damages to
the skin, liver,
stomach and thyroid.
Contamination of
pregnant women is
very risky and
research results
show that it can be
carcinogen
This chemical
compound could drip
through subsurface
layers reaching water
and contaminating it
if buried in landfills.
Because it is poorly
soluble, it is very
dangerous when it
enters water currents
as it could
contaminate the
chain of production
of some foods.
Tetra Bromo
Bisphenol-A
(TBBPA)
TBBA is a flame-
retardant, which is
use in computer
motherboards. This
compound
represents 50% of
all
bromined flame-
retardants
produced
It has not been prove
that it can cause
mutations or
carcinogen effects
on human beings.
Nevertheless, it has
been prove that
TBBA may interfere
in the transport and
metabolism of some
Unlike other flame-
retardants, TBBA
when used as a
reactive, bounds
chemically to plastic
or polymers for
protection. This
impedes its liberation
into the environment.
It is biodegradable
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worldwide. 96% of
all motherboards
use this chemical
compound which
represents 1 to 2%
of their weight
hormones. A
technical study has
demonstrated that
there is a direct
correlation between
TBBA in the blood
flow and in the air.
TBBA is toxic to
aquatic organisms
but one of the
products of this
biodegradation is
bisphenol, which can
cause damages to
the endocrine
system. The fact that
TBBA dissolves
poorly in water and
tends to adhere to
soil, where it can
reach food, has
created great
concern because
TBBA levels magnify
while passing
through the food
chain from 20 to
3200 times.Polybrominat
ed Biphenyls(PBB)
Originally, this
substance was addto plastics of
electronic
equipment for
inflammability
reduction.
Nevertheless, PBB
production in the
US was stop in1976 and in the
world in 2000.
Exposure to this
substance candamage kidneys,
liver and thyroids.
Fetuses that were
expose to PBB had
endocrinal problems.
Likewise it is
suspected that PBB
is carcinogen
PBB dissolves poorly
in water but canadhere strongly to
soil, through which it
could reach food. It
keeps magnifying
while passing along
the food chain.
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Polybrominat
ed Diphenyl
Ethers (PBDE)
PBDE is another
brominates flame-
retardant with its
number of bromine
atoms varying up
to 209 times. Three
types are sold for
commercial use
referred to as pent,
octa and deca, two
of them used in
electronic
equipment: octa,
used in high impact
housings, and deca
used in wire
insulation. Even
though the
production of this
compound has
decreased since
1999 its presence
in the environment
is increasing,
becoming a global
problem.
Since it was tested
for the first time in
1970, PBDE was
found in numerous
samples of human
tissue, and with
increasing
concentrations of
factor 100 in the last
30 years. Exposure
can occur the
moment that plastics
containing this
substance are
recycled. Concerns
for human health
arise because PBDE
containing 4 to 6
brominated
molecules that can
act as thyroxin,
damaging the
endocrine system.
Exposed children
show thyroid
damages and
neurological
anomalies.
PDBE is easily
liberated into the
environment and,
like other
flameretardants,
dissolves poorly in
water and strongly
adheres to soil,
crossing to
organisms, animals,
and food. This
crossing depends on
the brominated
concentration level;
the lower it is, the
more toxic PDBE gets
(for example when
exposed to UV Light).
This compound is
almost omnipresent,
as it is found both in
sea and fresh water
organisms,
mammals, birds and
water and soil
samples. When PBDE
is incinerated, it
produces dioxins and
furans.
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Chlorofluoroc
arbons (CFC)
CFC are used in
aerosol propellants,
cleansing agents,
foaming agents,
and
other packaging
materials like
solvents
and refrigerants. In
1987, a prohibition
campaign was
initiated reaching
its
objective in 1996,
an objective that
developing
countries aim to
reach in
2010.
There are no
significant impacts
on human health.
Nevertheless there
are indirect negative
effects. Fir example,
the release of CFC
attacks levels of the
atmosphere
When in contact with
the ozone layer, CFC
destroys it. One
chlorine atom is
responsible for the
destruction of
100.000 ozone
molecules. The ozone
layer protects earth
from radiation which
causes skin cancer
and blindness in
living beings
Polyvinyl
chloride (PVC)
PVC plastic is used
as an insulator incertain types of
wiring in electronic
equipment. Risks
arise from vinyl
chloride since this
compound is toxic
and the DEHP used
to soften PVCcarries great risks
to human health
In the amounts
present in theenvironment, there
is no proof that DEHP
causes damage to
humans
beings but it been
proven that it can
damage to lab
animal kidneys.Recent debates
about this compound
suggest that it can
cause endocrine and
gender anomalies in
This compound is
disseminated in theenvironment because
of its extended
usage, being soluble
in water if oils or
grease are present.
Bonds easily with soil
but also degrades
easily in contact withoxygen.
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embryos
Arsenic (As) Arsenic is present
in small amountsinelectronic
equipment in forms
such as Gallium
Arsenide Gas,
which
hassemiconductor
properties and can
befound inelectronic
equipment diodes.
Gas is carcinogen
and causes skin andlung cancers. The
most common
means of exposure is
direct contact with
dust containing this
compound especially
by workers of
semiconductormanufacturers.
Gallium Arsenide is
an inorganiccompound with low
water solubility. It is
transformed into an
organic compound
when bio-
accumulated in fish
and crustaceans.
Barium (Ba) Barium is generally
use in cathode
ray tubes (CRT) in
computer monitors.
When functioning in
the monitor thismetal reacts with
CO, CO2, N2, O2,
H2O y H2 which
produces a series
of
barium compounds
including oxides,
hydroxides andcarbonates.
Barium compounds
toxicity is link to its
solubility in water.
Some of these
compounds
produced in monitorsare extremely
soluble. Intake of
these compounds
can cause
gastrointestinal
disorders and muscle
weakness. Higher
doses can causechanges in heart
beat rate, paralysis
and death. Direct
contact with dust
containing barium
Its impact on the
environment
depends on its
solubility. Barium
compounds that are
highly soluble inwater are very
mobile and tend to
cumulate in aquatic
organisms
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can cause eye and
skin irritation.
Beryllium (Be) Beryllium is a metal
that generally
forms alloys with
copper to increaseits endurance,
conductivity and
elasticity. Initially,
Beryllium was used
in the production of
motherboards but
its major usage is
in contact circuits,relays and in some
laser printer
mechanisms
Beryllium is only
dangerous if inhaled,
as dust or fumes,
which could occurwhen electronic
equipment is
disassembled,
burned or crushed.
Its inhalation can
cause pneumonia,
respiratory
inflammation(chronic illness of
Beryllium) and can
raise the risk of lung
cancer
This metal doesnt
dissolve in water and
it remains into soil
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presence is small in
electronic
equipment where it
is used as a plastic
hardener and
protection layer for
some metal
components. When
electronic
components are
burned, 99% of
Chromium VI stays
in residuals and
ashes,
contaminating soil
in a toxic way,
which could reach
water currents with
significant higher
risk.
inhalation can cause
catarrh, nose
bleeding, ulcers and
sinus perforations.
Ingestion of
contaminated water
and food can
damage the
stomach, kidneys,
liver and cause
ulcers, convulsions
and even death. If
there is a direct
contact with skin it
can cause ulcers.
This metal is
carcinogen only
when inhaled.
attributed to
industrial plant
emissions, fuel
combustion in
commercial and
residential zones.
Lead (Pb) Lead is found inmany electronic
equipment
components. For
example,
in a PC, the largest
amount of this
metal is found in
the CRT of themonitor: 0 to 3% in
the panel, 70% in
the frit, 24% in the
funnel and 30% in
the neck. Lead is
Humans are exposedto this metal by
particle inhalation
and through
contaminated foods.
The first effects and
symptoms of lead
exposure are
anorexia, musclepain, malaise and
headache but an
extended exposure
can cause a
decrease in nervous
The chemicalstructure of this
metal is directly
affected by its pH but
most lead
compounds are
insoluble in water
and remain in that
state. They aredifficultly
accumulated in
plants or transferred
to food. Lead doesnt
bio-accumulate in
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also present in
weldings (40%),
motherboards,
circuits and wiring
plastic.
system performance,
weakness, brain
damage and even
death. Likewise, it
can affect the
reproductive system
both in men and
women and is
considered
carcinogen.
fish but it does in
other seafood. If
broken or incinerated
to the environment,
particles will be
transmitted by air
and soil.
Lithium (Li) Lithium is present
in computer
batteries andmodern electronic
equipment.
Typically batteries
contain an anode of
lithium or lithium
oxide, a
magnesium dioxide
(magnesium oxideand carbon)
cathode and lithium
salt dissolved in an
organic solvent.
This type of
batteries replaces
alkaline and NiCd
batteries. It isenvironmentally
more sustainable
than its
predecessors.
Lithium doesnt
cause toxicological
problems as lead,cadmium or mercury
do. But, a great risk
exists for workers
that have a direct
contact. Lithium is
classified as a
corrosive alkali that
can burn skin, eyesand, if inhaled,
lungs. To avoid these
risks lithium
batteries must not
be exposed to hot
environments or
broken, factors that
can cause thebattery to explode.
Not many studies
about the effects
oflithium on theenvironment have
beenpublished.
These compounds
tend to stay
dissolved in water
and they arent
easily absorbed
through soil.
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Mercury (Hg) Mercury is found in
three specific
places in a
computer. The
largest
amount is found in
LCD screen
fluorescent light,
computer or
monitor
switches, which
enable them to
shut
down while idle,
and finally in
batteries. Mercury
is very volatile and
easily liberated by
incineration or
breaking, which
could liberate up to
90% of the mercury
contained in the
monitor screen, for
example.
All forms of mercury
represent a risk to
human health, but
mercury in metal
form that is not
combined with other
components and
organic methyl
mercury are the
ones that possess
the greater risk,
especially to the
nervous system.
Short-term
exposures to this
compound cause
lung damage,
nausea, vomiting,
diarrhea, high
pressure, and, skin
and eye irritation.
Long or permanent
exposure might
cause permanent
damages to the
brain, kidneys and
fetus development,
besides neurological
changes, irritability,
tremors, short-
sightedness,
deafness, memory
problems, delirium,
hallucinations and
The impact of
mercury on the
environment has
been thoroughly
studied. Mercury in
pure form is
extremely volatile
and mining,
incineration and
manufacture release
this compound to the
atmosphere. When
mercury, in any of its
forms, gets in
contact with water or
soil, turns into
organic methyl
mercury by bacteria
action. In organic
form mercury is more
accessible to living
organisms and food.
Many studies have
shown mercury
presence in fish,
causing great
concern in many
regions worldwide.
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suicidal tendencies.
Nckel (Ni) Nickel is present in
the batteries of
some electronic
equipment (NiCd),
which are being
gradually replaced
with lithium
batteries. Likewise,
nickel
is used in CRT of
computer monitors
Nickel causes skin
damages and
asthma symptoms in
about 10 to 20% of
the population that
has direct contact.
Workers that are
exposed to dust
containing nickel
suffer bronchitis and
lung damages. There
is evidence that
many nickel
compounds such as
nickel hydroxide are
carcinogen
Nickel generally
enters the
environment through
air. These particles
are then placed in
water and soil,
especially if they
contain magnesium
and steel.
Nevertheless, this
compound does not
bio-accumulate in
living organisms.
Antimony (Sb) Antimony is present
in electronic
equipment in small
quantities.
Antimony trioxide is
Elevated exposure to
antimony via
electronic equipment
is unlikely.
Experiments in
Antimony released
into the environment
is commonly found in
soil and sediments.
Its mobility greatly
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added to plastic as
a flame-retardant.
This compound is
also used in the
CRT glass of
monitors and wire
welding.
animals have
emonstrated that
short-term exposure
can cause eye and
skin irritation, hair
loss, lung and heart
damages, and
fertility problems.
Antimony trioxide is
considered as
possibly carcinogen
depends on soil
structure, the form
which it takes, and
its pH. This element
is better absorbed in
soils containing steel,
magnesium or
aluminum.
Zinc Sulfide
(ZnS)
Zinc Sulfide is
mixed with othermetals
to create a
phosphor coating,
which is
used in the inside
of the monitor
glass.
Exposure to thiscompound happens
when the monitor
breaks.
This element is
corrosive to the skinand lungs and its
ingestion can be
very harmful
because it forms a
toxic gas (hydrogen
sulfide) within the
stomach
Zinc is one of the
most commonminerals in nature.
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9.0. Life Cycle of E-waste.
To ensure proper and nearly complete collection of used electronic equipments after they are
rendered useless, it is important to study the processes, which the equipment has undergone. That is
to say, the study of the life cycle of the equipment is equally relevant. The Fig. 5 shows the life span
of electronic equipments, taking into account that it may have switched users during the course of its
operational life. This course will have to be considered for effective collection so that maximum or
all of the E-Waste can be recycled.
For instance, computer hardware would appear to have up to 3 distinct product lives: the original life
or first product life (when it is being used by the primary user) and up to 2 further lives depending on
reuse. Fig. 5 depicts the flow of computer hardware units from point-of-sale to the original purchaser
and on to the reuse phases. The duration of the products first life is estimated to be between 2 and 4
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years for corporate users and between 2 and 5 years for domestic users. The life cycle of computer
waste is defined as, the period from when it is discarded by the primary user to when it goes for
recycling or is disposed of in a landfill.
Product manufacturer
Material recycling
Primary user second user third/fourth user landfill
Fig-2Flow of E-waste During Its Life Cycle
10.0. MANAGEMENT OF E-WASTES
It is estimated that 75% of electronic items are stored due to uncertainty of how to manage it. These
electronic junks lie unattended in houses, offices, warehouses etc. and normally mixed with
household wastes, which are finally disposed off at landfills. This necessitates implementable
management measures.
In industries management of e-waste should begin at the point of generation. This can be done by
waste minimization techniques and by sustainable product design. Waste minimization in industries
involves adopting:
inventory management,
production-process modification,
volume reduction,
recovery and reuse.
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10.1.Inventory management
Proper control over the materials used in the manufacturing process is an important way to reduce
waste generation (Freeman, 1989). By reducing both the quantity of hazardous materials used in the
process and the amount of excess raw materials in stock, the quantity of waste generated can be
reduced. This can be done in two ways i.e. establishing material-purchase review and control
procedures and inventory tracking system.
Developing review procedures for all material purchased is the first step in establishing an inventory
management program. Procedures should require that all materials be approved prior to purchase. In
the approval process all production materials are evaluated to examine if they contain hazardous
constituents and whether alternative non-hazardous materials are available.
Another inventory management procedure for waste reduction is to ensure that only the needed
quantity of a material is ordered. This will require the establishment of a strict inventory tracking
system. Purchase procedures must be implemented which ensure that materials are ordered only on
an as-needed basis and that only the amount needed for a specific period of time is ordered.
10.2.Production-process modification
Changes can be made in the production process, which will reduce waste generation. This reduction
can be accomplished by changing the materials used to make the product or by the more efficient use
of input materials in the production process or both. Potential waste minimization techniques can be
broken down into three categories:
i) Improved operating and maintenance procedures,
ii) Material change and
iii)Process-equipment modification.
Improvements in the operation and maintenance of process equipment can result in significant waste
reduction. This can be accomplished by reviewing current operational procedures or lack of
procedures and examination of the production process for ways to improve its efficiency. Instituting
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standard operation procedures can optimise the use of raw materials in the production process and
reduce the potential for materials to be lost through leaks and spills. A strict maintenance program,
which stresses corrective maintenance, can reduce waste generation caused by equipment failure. An
employee-training program is a key element of any waste reduction program. Training should
include correct operating and handling procedures, proper equipment use, recommended
maintenance and inspection schedules, correct process control specifications and proper
management of waste materials.
Hazardous materials used in either a product formulation or a production process may be replaced
with a less hazardous or non-hazardous material. This is a very widely used technique and is
applicable to most manufacturing processes. Implementation of this waste reduction technique may
require only some minor process adjustments or it may require extensive new process equipment.For example, a circuit board manufacturer can replace solvent-based product with water-based flux
and simultaneously replace solventvapor degreaser with detergent parts washer.
Installing more efficient process equipment or modifying existing equipment to take advantage of
better production techniques can significantly reduce waste generation. New or updated equipment
can use process materials more efficiently producing less waste. Additionally such efficiency
reduces the number of rejected or off-specification products, thereby reducing the amount of
material which has to be reworked or disposed of. Modifying existing process equipment can be a
very cost-effective method of reducing waste generation. In many cases the modification can just be
relatively simple changes in the way the materials are handled within the process to ensure that they
are not wasted. For example, in many electronic manufacturing operations, which involve coating a
product, such as electroplating or painting, chemicals are used to strip off coating from rejected
products so that they can be recoated. These chemicals, which can include acids, caustics, cyanides
etc are often a hazardous waste and must be properly managed. By reducing the number of parts that
have to be reworked, the quantity of waste can be significantly reduced.
10.3. Volume reduction
Volume reduction includes those techniques that remove the hazardous portion of a waste from a
non-hazardous portion. These techniques are usually to reduce the volume, and thus the cost of
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disposing of a waste material. The techniques that can be used to reduce waste-stream volume can be
divided into 2 general categories: source segregation and waste concentration. Segregation of wastes
is in many cases a simple and economical technique for waste reduction. Wastes containing different
types of metals can be treated separately so that the metal value in the sludge can be recovered.
Concentration of a waste stream may increase the likelihood that the material can be recycled or
reused. Methods include gravity and vacuum filtration, ultra filtration, reverse osmosis, freeze
vaporization etc.
For example, an electronic component manufacturer can use compaction equipments to reduce
volume of waste cathode ray-tube.
10.4.Recovery and reuse
This technique could eliminate waste disposal costs, reduce raw material costs and provide income
from a salable waste. Waste can be recovered on-site, or at an off-site recovery facility, or through
inter industry exchange. A number of physical and chemical techniques are available to reclaim a
waste material such as reverse osmosis, electrolysis, condensation, electrolytic recovery, filtration,
centrifugation etc. For example, a printed-circuit board manufacturer can use electrolytic recovery to
reclaim metals from copper and tin-lead plating bath.
However recycling of hazardous products has little environmental benefit if it simply moves the
hazards into secondary products that eventually have to be disposed of. Unless the goal is to redesign
the product to use nonhazardous materials, such recycling is a false solution.
10.5.Sustainable product design
Minimization of hazardous wastes should be at product design stage itself keeping in mind the
following factors*
Rethink the product design: Efforts should be made to design a product with fewer amounts
of hazardous materials. For example, the efforts to reduce material use are reflected in some
new computer designs that are flatter, lighter and more integrated. Other companies propose
centralized networks similar to the telephone system.
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Use of renewable materials and energy: Bio-based plastics are plastics made with plant-
based chemicals or plant-produced polymers rather than from petrochemicals. Bio-based
toners, glues and inks are used more frequently. Solar computers also exist but they are
currently very expensive.
Use of non-renewable materials that are safer: Because many of the materials used are non-
renewable, designers could ensure the product is built for re-use, repair and/or
upgradeability. Some computer manufacturers such as Dell and Gateway lease out their
products thereby ensuring they get them back to further upgrade and lease out again.
11.0. Waste management concepts:
The waste hierarchies there are a number of concepts about waste management, which vary in theirusage between countries or regions. The waste hierarchy:
reduce
reuse
recycle
Classifies waste management strategies according to their desirability. The waste hierarchy has
taken many forms over the past decade, but the basic concept has remained the cornerstone of most
waste minimization strategies. The aim of the waste hierarchy is to extract the maximum practical
benefits from products and to generate the minimum amount of waste. Some waste management
experts have recently incorporated a 'fourth R': "Re-think", with the implied meaning that the present
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system may have fundamental flaws, and that a thoroughly effective system of waste management
may need an entirely new way of looking at waste.
Some "re-think" solutions may be counter-intuitive, such as cutting fabric patterns with slightly
more "waste material" left -- the now larger scraps are then used for cutting small parts of the
pattern, resulting in a decrease in net waste. This type of solution is by no means limited to the
clothing industry. Source reduction involves efforts to reduce hazardous waste and other materials
by modifying industrial production.
Source reduction methods involve changes in manufacturing technology, raw material inputs, and
product formulation. At times, the term "pollution prevention" may refer to source reduction.
Another method of source reduction is to increase incentives for recycling. Many communities in the
United States are implementing variable rate pricing for waste disposal (also known as Pay as You
Throw - PAYT) which has been effective in reducing the size of the municipal waste stream. Source
reduction is typically measure by efficiencies and cutbacks in waste. Toxics use reduction is a more
controversial approach to source reduction that targets and measures reductions in the upstream use
of toxic materials.
Toxics use reduction emphasizes the more preventive aspects of source reduction but due to its
emphasis on toxic chemical inputs, has been oppose more vigorously by chemical manufacturers.
11.1.Resource recovery
A relatively recent idea in waste management has been to treat the waste material as a resource to be
exploited, instead of simply a challenge to be managed and disposed of. There are a number of
different methods by which resources may be extracted from waste: the materials may be extracted
and recycled, or the calorific content of the waste may be converted to electricity.
The process of extracting resources or value from waste is variously referred to as secondary
resource recovery, recycling, and other terms. The practice of treating waste materials as a resource
is becoming more common, especially in metropolitan areas where space for new landfills is
becoming scarcer.
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There is also a growing acknowledgement that simply disposing of waste materials is unsustainable
in the long term, as there is a finite supply of most raw materials. There are a number of methods of
recovering resources from waste materials, with new technologies and methods being developed
continuously.
In some developing nations some resource recovery already takes place by way of manual laborers
who sift through un-segregated waste to salvage material that can be sold in the recycling market.
These unrecognized workers called waste pickers or rag pickers, are part of the informal sector,
but play a significant role in reducing the load on the Municipalities' Solid Waste Management
departments.
There is an increasing trend in recognizing their contribution to the environment and there are efforts
to try and integrate them into the formal waste management systems, which is proven to be both cost
effective and also appears to help in urban poverty alleviation. However, the very high human cost
of these activities including disease, injury and reduced life expectancy through contact with toxic or
infectious materials would not be tolerate in a developed country.
11.2.Recycling
Recycling means to recover of other use a material that would otherwise be consider waste.
The popular meaning of recycling in most developed countries has come to refer to the widespread
collection and reuse of various everyday waste materials. They are collected and sorted into common
groups, so that the raw materials from these items can be used again (recycled).
In developed countries, the most common consumer items recycled include aluminum beverage
cans, steel, food and aerosol cans, HDPE and PET plastic bottles, glass bottles and jars, paperboard
cartons, newspapers, magazines, and cardboard. Other types of plastic (PVC, LDPE, PP, and PS) are
also recyclable, although not as A materials recovery facility, where different materials are separated
for recycling commonly collected. These items are usually composed of a single type of material,
making them relatively easy to recycle into new products.
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The recycling of obsolete computers and electronic equipment is important, but more costly due to
the separation and extraction problems.
Electronic waste is send to Asia, where recovery of the gold and copper can cause environmental
problems Recycled or used materials have to compete in the marketplace with new (virgin)
materials.
The cost of collecting and sorting the materials often means that they are equally or more expensive
than virgin materials. This is most often the case in developed countries where industries producing
the raw materials are well established. Practices such as trash picking can reduce this value further,
as choice items are removing (such as aluminum cans).
In some countries, recycling programs are subsidized by deposits paid on beverage containers. The
economics of recycling junked automobiles also depends on the scrap metal market except where
recycling is mandated by legislation (as in Germany). However, most economic systems do not
account for the benefits to the environment of recycling these materials, compared with extracting
virgin materials. It usually requires significantly less energy, water and other resources to recycle
materials than to produce new materials. For example, recycling 1000 kg of aluminum cans saves
approximately 5000 kg of bauxite ore being mined (source: ALCOA Australia) and prevents the
generation of 15.17 tones CO2eq greenhouse gases; recycling steel saves about 95% of the energy
used to refine virgin ore (source: U.S. Bureau of Mines).
In many areas, material for recycling is collect separately from general waste, with dedicated bins
and collection vehicles. Other waste management processes recover these materials from general
waste streams. This usually results in greater levels of recovery than separate collections of
consumer-separated beverage containers, but are more complex and expensive.
11.3. Waste management techniques
Managing municipal waste, industrial waste and commercial waste has traditionally consisted of
collection, followed by disposal. Depending upon the type of waste and the area, a level of
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processing may follow collection. This processing may be to reduce the hazard of the waste, recover
material for recycling, produce energy from the waste, or reduce it in volume for more efficient
disposal.
11.3.1. Landfill:
Disposing of waste in a landfill is the most traditional method of waste disposal, and it remains a
common practice in most countries. Historically, landfills were often established in disused quarries,
mining voids or borrow pits.
A properly-designed and well-managed landfill can be a hygienic and relatively inexpensive method
of disposing of waste materials in a way that minimizes their impact on the local environment.
Older, poorly-designed or poorly-managed landfills can create a number of adverse environmental
impacts such as
Wind-blown litter,
Attraction of vermin, and
Generation of leach ate which can pollute groundwater and surface water.
Another byproduct of landfills is landfill gas (mostly composed of methane and carbon dioxide),
which is produced as organic waste breaks down an aerobically. This gas can create odor problems,
kill surface vegetation, and is a greenhouse gas.
Design characteristics of a modern landfill are:-
Include methods to contain leach ate, such as clay or plastic lining material.
Disposed waste is normally compacted to increase its density and stabiles the new landform,
covered to prevent attracting vermin (such as mice or rats) and reduce the amount of wind-
blown litter. landfills also landfill compaction vehicles in operation have a landfill gas
extraction system installed after closure to extract the landfill gas generated by the
decomposing waste materials.
Gas is pumped out of the landfill using perforated pipes and flared off or burnt in a gas
engine to generate electricity.
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Even flaring the gas is a better environmental outcome than allowing it to escape to the
atmosphere, as this consumes the methane, which is a far more potent greenhouse gas than
carbon dioxide.
Many local authorities, especially in urban areas, have found it difficult to establish new landfills
due to opposition from owners of adjacent land. Few people want a landfill in their local
neighborhood. As a result, solid waste disposal in these areas has become more expensive as
material must be transported further away for disposal.
This fact, as well as growing concern about the impacts of excessive materials consumption, has
given rise to efforts to minimize the amount of waste sent to landfill in many areas. These efforts
include taxing or levying waste sent to landfill, recycling the materials, converting material to
energy, designing products that use less material, and legislation mandating that manufacturers
become responsible for disposal costs of products or packaging. A related subject is that of industrial
ecology, where the material flows between industries is studied. The by-products of one industry
may be a useful commodity to another, leading to a reduced materials waste stream.
Some futurists have speculated that landfills may one day be mined: as some resources become
scarcer, they will become valuable enough that it would be economical to 'mine' them from landfillswhere these materials were previously discarded as valueless. A related idea is the establishment of a
'mono-fill' landfill containing only one waste type (e.g. waste vehicle tyres), as a method of long-
term storage.
11.3.2. Incineration:
Incineration is a waste disposal method that involves the combustion of waste at high temperatures.
Incineration and other high temperature waste treatment systems are described as "thermal
treatment". In effect, incineration of waste materials converts the waste into heat, gaseous emissions,
and residual solid ash.
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Other types of thermal treatment include pyrolysis and gasification. A waste-to-energy plant (WtE)
is a modern term for an incinerator that burns wastes in high-efficiency furnace/boilers to produce
steam and/or electricity and incorporates modern air pollution control systems and continuous
emissions monitors.
This type of incinerator is sometimes called an energy-from-waste (EfW) facility. Incineration is
popular in countries as Japan where land is a scarce resource, as they do not consume as such area as
a landfill.
Sweden has been a leader in using the energy generated from incineration over the past 20 years.
Denmark also extensively uses waste-to-energy incineration in localised combined heat and power
facilities supporting district-heating schemes.
Incineration is carried out both on a small scale by individuals, and on a large scale by industry. It is
recognised as a practical method of disposing of certain hazardous waste materials (such as
biological medical waste), though it remains a controversial method of waste disposal in many
places due to issues such as emission of gaseous pollutants.
11.3.3. Composting and anaerobic digestion :
Active compost heap Waste materials that are organic in nature, such as plant material, food scraps,
and paper products, are increasingly being recycled. These materials are put through a composting
and/or digestion system to control the biological process to decompose the organic matter and kill
pathogens.
The resulting stabilized organic material is then recycled as mulch or compost for agricultural or
landscaping purposes. There are a large variety of composting and digestion methods and
technologies, varying in complexity from simple windrow composting of shredded plant material, to
automated enclosed-vessel digestion of mixed domestic waste. These methods of biological
decomposition are differentiated as being aerobic in composting methods or anaerobic in digestion
methods, although hybrids of the two methods also exist.
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11.3.4. Mechanical biological treatment;
Mechanical biological treatment (MBT) is a technology category for combinations of mechanical
sorting and biological treatment of the organic fraction of municipal waste.
MBT is also sometimes termed BMT- Biological Mechanical Treatment however; this simply refers
to the order of processing.
The "mechanical" element is usually a bulk handling mechanical sorting stage. This either removes
recyclable elements from a mixed waste stream (such as metals, plastics and glass) or processes it in
a given way to produce a high calorific fuel given the term refuse derived fuel (RDF) that can be
used in cement kilns or power plants. Systems, which are configure to produce RDF, include
Herhofand Ecodeco. It is a common misconception that all MBT processes produce RDF. This is not
the case. Some systems such as Arrow Bio simply recover the recyclable elements of the waste in a
form that can be sending for recycling. Arrow Bio UASB anaerobic digesters, Hiriya, Tel Aviv,
Israel The "biological" element refers to either anaerobic digestion or composting.
Anaerobic digestion breaks down the biodegradable component of the waste to produce biogas and
soil conditioner. The biogas can be use to generate renewable energy. More advanced processes such
as the Arrow-Bio Process enable high rates of gas and green energy production without the
production of RDF. This is facilitate by processing the waste in water. Biological can also refer to a
composting stage.
Here the organic component is treat with aerobic microorganisms. They break down the waste into
carbon dioxide and compost. There is no green energy produced by systems simply employing
composting. MBT is gaining increased recognition in countries with changing waste management
markets where WSN Environmental Solutions has taken a leading role in developing MBT plants.
11.3.5. Pyrolysis & gasification:
Pyrolysis and gasification are two related forms of thermal treatment where waste materials are
heated to high temperatures with limited oxygen availability.
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The process typically occurs in a sealed vessel under high pressure. Converting material to energy
this way is more efficient than direct incineration, with more energy able to be recovered and used.
Pyrolysis of solid waste converts the material into solid, liquid and gas products. The liquid oil and
gas can be burn to produce energy or refined into other products.
The solid residue (char) can be further refined into products such as activated carbon.
Gasification is use to convert organic materials directly into a synthetic gas (syn-gas) composed of
carbon monoxide and hydrogen. The gas is then burn to produce electricity and steam. Gasification
is use in biomass power stations to produce renewable energy and heat.
12.0. Recycling of e-wasteThe conventional e-waste processing and recycling is basically a five-step process
1. Generation and Stockpiling
Many different economic actors purchase, use, and then stockpile or discard electronic waste.
These range from manufacturers such as MNCs to large and small businesses, households,
institutions, and non-profit organizations.
2. Collection
There are wide varieties of possible collection alternatives for this e-waste. Varieties of entities are
providing these services including the electronics industry, private or nonprofit recycling services,
and the public sector through the solid waste management and recycling infrastructure.
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3. Handling & Brokering
The next link in the cycle is the handling and brokering services. Here computers, TVs, monitors and
other collected electronics are consolidated and made ready for processing and/or sorted to
determine what equipment can be refurbished or reused as whole units and what equipment must be
disassembled for commodity processing.
4. Processing
After electronic equipment is dismantling, it is then process into either feedstock for new production
or refurbished into new equipment. Outputs from de-manufacturing activities include scrap
commodities such as glass, plastics, and metals the primary elements from which all electronic
hardware is made. For export, and to a lesser extent national processing markets, there are significant
issues associated with the environmental and health practices of current service providers in this part
of the cycle.
5. Production
The final step in this cycle is to turn the processed commodities or refurbished whole electronics
back into new products for sale and consumption by end users. There are many different players and
industries involved in this production process. The recycling fraction is miniscule compared with the
production of product using virgin materials. The substances procured by recycling may be use for
several purposes, even for manufacturing the very same equipments they were derived from.
12.1. Recycling/Recovery System
First of the operations involves dismantling and rapid separation of primary materials. The following
materials are separate for further recycling:
Material containing copper: Including printer and other motors, wires and cables, CRT yokes,
circuit boards, etc
Steel: Including internal computer frames, power supply housings, printer parts, washing machines,
refrigerator, etc.
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Plastic: Including housings of computers, printers, faxes, phones, monitors, keyboards, etc.
Copper: Extracted from transformer and CRT after their dismantling
Circuit Boards: These come from many applications including computers, phones, disc drives,
printers, monitors, etc. Each of these processes has been described below. Following describes the
conventional way of recycling a personal computer.
12.2.Bifurcation of electronic scrap
11.2.1. Printed Circuit Boards (PCBs)
The printed circuit boards contain heavy metals such as antimony, gold, silver, chromium, zinc, lead,
tin and Copper. According to some estimates, there is hardly any other product for which the sum of
the environmental impacts for raw material, industrial refining and production, use and disposal is as
extensive as for printed circuit boards. The methods of salvaging material from circuit boards are
highly destructive and harmful as they involve heating and open burning for the extraction of metals.
Even after such harmful methods are used, only a few of the materials are recovered. The recycling
of circuit boards, drawn from monitors, CPU, disc and floppy drives, printers, etc. involves a numberof steps.
12.2.2. Characteristics of PCB Scrap
PCB scrap is characterise by significant heterogeneity and relatively high complexity, although with
the levels of complexity being somewhat greater for populated scrap boards. As has been seen in
respect of materials composition, the levels of inorganic in particular are diverse with relatively low
levels of precious metals being present as deposited coatings of various thicknesses in conjunction
with copper, solders, and various alloy compositions, non ferrous and ferrous metals. In spite of the
inherent heterogeneity and complexity, there are too many differences in the intrinsic physical and
chemical properties of the many materials and components present in scrap PCBs, and indeed
electronic scrap as a whole, to permit recycling approaches that separate such into their individual
fractions.
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The following characteristics ultimately govern mechanical and hydrometallurgical separation and it
is based upon such that current and potential recycling techniques and infrastructures have been
envisaged, developed and implemented:-
12.2.2.1. Density Differences
Differences in density of the materials contained within scrap PCBs have formed the basis for
separation methods subsequent to their liberation as free constituents. The specific gravity ranges of
typical materials are as shown below:-
Table-3
Materials Specific Gravity Range (g/cm3)Gold, platinum group, tungsten 19.3 - 21.4
Lead, silver, molybdenum 10.2 - 11.3
Magnesium, aluminium, titanium 1.7 - 4.5
Copper, nickel, iron, zinc 7.0 - 9.0
GRP 1.8 - 2.0
With these densities not being significantly affected by the addition of alloying agents or other
additives, it is predictable that the deployment of various density separation systems available within
the raw materials process industry may be utilized to effect separation of liberated constituents of a
similar size range.
The utilization of density differences for the recovery of metals from PCB scrap has been
investigated on many occasions and air classifiers have been used extensively to separate the non
metallic (GRP) constituents, whilst sink-float and table separation techniques have been utilised to
generate non ferrous metal fractions.
Air techniques that effectively combine the actions of a fluidised bed, a shaking table and an air
classifier, have been successfully implemented in applications involving a diversity of electronic
scrap separations. It is essential, as has been noted, that the feed material must be of a narrow size
range to guarantee effective stratification and separation.
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12.2.2.2. Magnetic and Electrical Conductivity Differences
Ferrous materials may be readily separate with the application of low intensity magnetic separators
that have been well developing in the minerals processing industry.
Many non-ferrous materials in respect of their high electrical conductivity may be separated by
means of electrostatic and eddy current separators. Eddy current separation has been developing
within the recycling industry since strong permanent magnets, such as iron boron- neodymium, have
become available.
Rotating belt type eddy current separation is the most extensively used approach for the recovery of
nonferrous metal fractions. In application, the alternating magnetic fields caused by the rapidly
rotating wheel mounted with alternating pole permanent magnets result in the generation of eddy
currents in non-ferrous metal conductors, which in turn, generate a magnetic field that repels the
original magnetic field.
The resultant force, arising from the repulsive force and the gravitational force permits their
separation from non-conducting materials.
12.2.2.3. Polyformity
One of the important aspects of both PCB and electronic scrap is the polyformity of the various
materials and components and the effect this can have on materials liberation. It is essential that any
shredding and separation processes take this into account. In eddy current separation, the shape of
conducting components, in addition to their particle sizes and conductivity/density ratios, has a
significant effect on the generated repulsive forces that ultimately govern the separation efficiency.
For instance, multiple induced current loops may be establishing in conductors with irregular shapes
with the induced magnetic fields counteracting each other and reducing the net repulsive force.
12.2.2.4. Liberation Size
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The degree of liberation of materials upon shredding (to cut or tear into small pieces) and
comminuting (to pulverize) is crucial (trying) to the efficiency and effectiveness of any subsequent
separation process in respect of yield, quality of recovered material and energy consumption of the
process.
This is especially critical in mechanical separation approaches. The comminuting of scrap PCBs has
been shows to generate a high level of material liberation and levels as high as 96% to 99% have
been report for metallic liberation after comminuting to sub 5mm particulates. It must noted,
however, that a continual observation from recyclers is that liberation levels such as these are
atypical (not typical) of actual yields and that a fundamental constraint on mechanical processing is
the loss, particularly of precious metal content, that appears to be inherent due primarily to the nature
of many plastic-metal interfaces.
12.2.2.5. Chemical Reactivity
Hydrometallurgical approaches depend on selective and non-selective dissolution to achieve a
complete solublesation of all the contained metallic fractions within scrap PCBs. Although all
hydrometallurgical approaches clearly benefit from prior comminution this is primarily undertaken
to reduce bulk volume and to expose a greater surface area of contained metals to the etching
(corrosive action of an acid instead of by a burin) chemistry.
Selective dissolution approaches may utilise high capacity etching chemistries based on cupric
chloride or ammonium sulphate for copper removal, nitric acid based chemistries for solder
dissolution and aqua regia for precious metals dissolution, where as non selective dissolution may be
carried out with either aqua regia or chlorine based chemistry.
12.2.2.6. Electropositivity
Dissolved metals generated via chemical dissolution are present as ionised species within an aqueous
media and may be recovered via high efficiency electrolytic recovery systems.
In the instance of selective dissolution, a single metal is recovered as pure electrolytic grade
material, usually in sheet form; from the spent etching solution with certain etching chemistries
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permitting regeneration of the liquors for reuse as etch chemistries. In the instance of selective
dissolution, use may be made of the differing electro-positivity of the contained ionised metallic
species to selective recovery metals at discrete levels of applied voltage.
12.3.Disassembly
Disassembly in practice
In the practice of recycling of waste electric and electronic equipment, selective disassembly
(dismantling) is an indispensable process since:
(1) The reuse of components has first priority,
(2) Dismantling the hazardous components is essential,
(3) It is also common to dismantle highly valuable components and high-grade materials such as
printed circuit boards, cables, and engineering plastics in order to simplify the subsequent recovery
of materials.
Most of the recycle plants utilize manual dismantling. The main obstacles preventing automated
disassembly from becoming a commercially successful activity are:
(1) Too many different types of products,
(2) the amount of products of the same type is small,
(3) General disassembly-unfriendly product design,
(4) General problems in return logistics and
(5) Variations in returned amounts of products to be disassembled. Fortunately, research in
the field of product design for disassembly has gained momentum in the past decade.
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One good idea is self-disassembly, which is called active disassembly using smart materials
(ADSM). Chiodo reported the application of shape memory polymer (SMP) technology to the active
disassembly of modern mobile phones. The smart material SMP of polyurethane (PU) composition
was employed in the experiments. This method provides a potential dismantling scenario for the
removal of all components if this material was to be developed for surface mount components.
Research into using ADSM in other small electronics also has been done to handle units such as
telephones, cell phones, PCB/component assemblies, cameras, battery chargers, photocopier
cartridges, CRTs, computer casings, mice, keyboards, game machines nd stereo equipment.
12.4.Mechanical/physical