Rishiraj Instetuet of Technology, Indore

8/14/2019 Rishiraj Instetuet of Technology, Indore

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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

Rishiraj Instetuet of Technology, Indore

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