solid waste and e-waste

1. VI. SOLID WASTE
POLLUTION

2. •Solid wastes are the useless, unwanted, or undesirable
solid and semisolid substances, discarded by man. They
include garbage, trash, rubbish, refuse, ash and residues,
waste tyre, sludge from treatment plants, demolition
waste, construction waste, dead animals, radioactive
substances, and so on. Solid waste pollution depends
heavily on the living standards and life styles of human
population. It is relatively more severe in industrial
towns and cities than in agricultural villages.
•Solid wastes are of three general categories, namely
municipal solid wastes, hazardous industrial wastes and
biomedical wastes.

3. (a) Municipal solid wastes
• Municipal wastes are the non-radioactive and non-hazardous solid or semi-
solid wastes from household activities, hotels, restaurants, public places,
institutions, vegetable markets, butcher shope, fish markets, automobile
workshops, street- sweepings, etc. They include putrescible and non-
putrescible wastes, such as gar- bage, rubbish, trash, refuse, ash, paper,
discarded appliances, carcasses, construction and demolition wastes, etc.
• The major sources of municipal wastes are residential centres, commercial
complexes and open places (streets, markets, beaches, parks, etc.). Human
population explosion, fast progress in urbanization and industrialisation,
and rapid changes in the life style of mankind have considerably augmented
municipal solid waste pollution.

4. (b) Hazardous industrial wastes
• Hazardous wastes are the highly dangerous or lethal wastes or mixtures of
wastes. They can cause or contribute to mortality, irreversible illnesses, and
incapacitating reversible illnesses. Also, they cause potential environmental
hazards, when improp- erly handled, treated, stored or transported. So,
their handling and disposal require sufficient precautions.
• In general, hazardous wastes are toxic, carcinogenic, mu- tagenic,
teratogenic, ignitable, corrosive, and chemically reactive, or explosive
substances, seriously harmful to plants and animals.
• Their effects may be immediate or belated. Radioactive substances, reactive
chemicals, inflammable wastes, explosives, toxic metals and metallic
compounds, asbestos, arsenic, etc. are hazardous wastes. The common
toxic metals include lead, mercury, manganese, cadmium, chromium, iron,
nickel, etc. The major sources of hazardous wastes are industries, nuclear
plants, hospitals, research institutes, laboratories, etc.

5. (c) Biomedical wastes
• Biomedical wastes are the solid wastes generated from health care
activities, such as diagnosis, treatment and prevention of diseases,
alleviation of disablement, and medical research studies at hospitals,
nursing homes, clinics, research centres, blood banks, veterinary
institutions, etc.
• In India, biomedical wastes are classified under ten categories (see
box item). Health risks of these wastes include several diseases, such
as AIDS, hepatitis Band C, gastroenteric diseases, respiratory
infections, skin infections, etc.

6. Major causes of solid waste pollution
•The major causes for the rapid increase in solid waste
pollution include human population explosion, extensive
urbanization, social and economic affluence of mankind,
technological advancements, etc.
•(i) Human population explosion
•Perhaps, the major reason for all types of environmental
pollution is the rapid growth of human population.
Increased utilization of resources by the booming
millions simultaneously causes the corresponding
accumulation of solid wastes also.

7. • (ii) Urbanization
• Solid waste is mostly an urban product. So, solid waste pollution
increases with fast strides in urbanization. In developed countries,
the quantity of solid wastes has gone beyond all proportions, making
their timely disposal a Herculian task.
• (iii) Affluence
• Economic growth of mankind has caused a corresponding increase in
per capita consumption also. Consequently, there is a growing
tendency among the people to discard usable items for replacing
them with new types. This considerably contributes to solid waste
pollution.

8. Impacts of solid waste pollution
• Accumulation of solid wastes and their improper and inadequate
management and disposal often cause serious environmental
problems and health hazards. Environmental problems include
contamination of water supplies, poisoning of the soil and ground
water, destruction of habitats and damages to ecosystems. Some of
the effect of solid waste pollution are the following:
• (i) Some toxic wastes, especially metallic wastes, are toxic,
mutagenic, carcino- genic, or teratogenic agents. So, they may poison
living systems, induce abnor- mal mutations, cause cancers and
promote abnormal embryonic development (teratogeny).

9. •(ii) Diseases, such as bacillary dysentery, amoebic dysentery,
diarrhoea, etc., often result from food and drinking water,
contaminated with solid wastes through flies.
•(ii) Spreading of plague through rats which feed on solid
wastes.
•(iii) Fast spreading of cholera, jaundice, hepatitis,
gastrointestinal diseases, etc. through drinking water and
vegetables, contaminated with wastes.
•(iv) Solid wastes sometimes block drains and gully pits and
cause water logging. This, in turn, favours the breeding of
mosquitoes and thereby promotes the spreading of malaria,
filariasis, dengue fever, chikungunya, etc.

10. •(v) Decomposition of organic solid wastes produces
obnoxious or odourous gases, unpleasant and harmful to
human beings.
•(vi) Burning of some solid wastes, such as plastics,
rubber, etc., produces noxious fumes which pollute the
atmosphere.
•(vii) Percolation of decomposed garbage pollutes soil and
underground water.

12. SOLID WASTE MANAGEMENT
[Disposal of solid wastes]
• Solid waste management consists of two major areas, namely
disposal of munici- pal solid wastes and disposal of hazardous solid
wastes.
I. Disposal of municipal solid wastes
• Disposal of municipal solid wastes involves several methods which
vary with the accumulated solid material. The common methods
include landfilling, recycling, incineration, pulverization, pyrolysis,
composting and dumping into sea.

13. (i) Landfilling of solid wastes
• Landfilling is the cheapest and the commonest method of disposal of
municipal solid wastes. In this method, solid wastes are dumped in
successive layers, one above another, in low-lying land areas.
• Each layer is nearly 1.5m thick, and is covered by 20-25cm thick soil.
It is left out for a week or more, before filling the next layer.
Compaction by trucks will cause settlement.
• Spraying of insecticides is also necessary to prevent the breeding of
mosquitoes, flies, etc. In course of time, the solid waste will get
stabilized by the decomposition and the subsequent conversion of its
organic matter into stable compounds.

14. •Hydrolysis of complex organic matter may occur
under anaerobic conditions, releasing CO2, CH4, HS
and other gases and producing simple, water-
soluble organic acids. The whole waste gets
stabilized in a few months and settles down by 20-
40% of its original thickness.
•In the non-availability of low-lying areas, 'trenching'
is adopted for solid waste disposal. In this method,
4-10m long, 2-3 m wide and 1-2m deep trenches
are excavated, leaving 2-3m wide strip in between
adjacent trenches. These trenches are then filled
with wastes and covered by soil.

15. • Landfilling is advantageous in that it is simple and cheap, costly treatment
plants, advanced technology and skilled labour are not required, separation
of the different kinds of wastes is not necessary, and no residues or
byproducts which require further disposal are left out.
• Also, landfilling is significant it that it enables the reclamation of low-lying
areas for better use.
• Landfilling is disadvantageous in several ways. It requires large land areas
and insecticide spraying, causes the continuous evolution of foul smell, and
results in the formation of leachate. Leachate is a coloured liquid, formed
due to the seepage of rain water into the landfills.
• In it, some harmful and carcinogenic compounds of the waste dissolve.
Contamination of the water with leachate may cause cholera, typhoid,
polio,etc.

16. (ii) Recycling of solid wastes
• Recycling or salvaging of solid wastes is the recovery of some of their
components for using as raw materials. It is perhaps the most eco-
friendly method of solid waste disposal.
• In this process, materials that can be recycled are first sorted out, then
processed, and finally used as raw materials, for the manufacture of
new useful products.
• Wood, paper, plastics, rubber, metals, glass, paper, clothes, agricultural
wastes, slaughter-house wastes, industrial and urban wastes, waste of
poultry feeds, etc. are now recycled and used as new products.

17. •Currently, recycling is an integral part of solid waste
management. In addition to waste disposal, it is
advantageous in many ways. Some of its advantages are the
following:
•1. Avoids wastage, conserves natural resources and energy,
and controls or re- duces environmental pollution.
•2. Enables the production of many cheaper and useful
products to meet the basic requirements of the common
man.
•3. Generates enough employment opportunities.
•4. Directly and indirectly contributes to economic growth.

18. (iii) Incineration or combustion of solid wastes
• Incineration or combustion is the burning of solid wastes in special
chambers, hearths, or furnaces. This method is generally employed
when ideal lanfilling areas are not available and dumping into sea is
not possible.
• The minimum temperature for incineration should always be well
above 670°C to burn all the combustible organic matter and oxidize the
foul-smelling gases.
• The final products of complete combustion include ashes and cynders.
Ashes can be used for filling low laying areas, and cynders can be used
as road materials.

19. • Current incineration technique involves the mass burning of solid wastes in hot
furnaces at temperatures above 1000°C. The heat energy from this process is
used to generate steam from water which, in turn, is used to drive turbines to
generate electricity.
• Incineration of solid wastes is advantageous in several ways as follows:
• 1. Incineration serves two purposes, namely waste disposal and generation of uti-
lizable energy.
• 2. Serves as a sanitary measure to destroy harmful and pathogenic organisms in
the waste.
• 3. Does not produce dust and foul odour.
• 4. Produces useful substances, such as ashes and cynders.
• Incineration of solid wastes is disadvantageous in that it incurs high initial
expenditure, and causes air pollution by smoke and ashes.

20. (iv) Pulverization of solid wastes
•Pulverization is the process by which solid wastes are
crushed and powdered in specialized grinding machines to
reduce their mass and modify their physical character.
•Pulverization makes the waste odourless and unattractive to
insects. The powdered waste is then disposed by landfilling.
Pulverization is very costly and so it is not commonly
employed for waste disposal.

21. (v) Pyrolysis of solid wastes
• Pyrolysis is the conversion of solid organic wastes to useful liquid fuels. It involves
the recovery of the chemical constituents and the chemical energy of some solid
organic wastes by a process called "destructive distillation."
• In pyrolysis, the combustible components of the solid waste are subjected to
thermal decomposition; they are heated in a specially designed chamber, called
pyrolysis reactor, at a temperature of 650-1000°C, under oxygen-free or low-
oxygen conditions.
• This produces useful petrochemicals and some amount of char. Pyrolysis differs
from incineration in that it is an endothermic process. The advantages of
pyrolysis are the same as those of incineration.
• Often, the residual char, produced in pyrolysis, is made to react with CO2 and
steam. The gas produced by this reaction is used in gas turbines or internal
combustion engines to generate electricity.

22. (vi) Composting of solid wastes
• Composting is the biological decomposition of the putrescible organic
constitu- ents of solid wastes into stable mineral compounds and a humus-
like material, called compost. The organisms involved in composting include
bacteria, fungi, earthworms, insects and some soil organisms.
• Composting of solid wastes is significant in three major respects as follows:
• 1. Serves as an eco-friendly method of solid waste disposal with minimum
financial expenditure.
• 2. Provides compost which is a valuable natural manure.
• 3. Is a most hygienic method without environmental pollution and health
risks. There are four major methods of composting, namely trench
composting, open window composting, mechanical composting and
vermicomposting.

23. (a) Trench composting
• In this method, 4-10m long, 2-3m wide, and 0.7-1.0m deep trenches
are excavated. Solid waste is spread in these trenches in successive
15cm thick layers, sandwiched by 5cm thick layers of semi-liquid
cattle dung, until the waste heap rises to 30cm or more above the
ground level. Then, a 5 -7.5 cm thick layer of soil is spread over the
top of the heap.
• This prevents wind-blowing of the waste and the entry of insects. In
about 4-5 months, decomposition is completed and the humus-like
compost gets stabilized. It is removed, sieved and used as a manure.

24. (b) Open window composting
•In this method, the solid waste is dumped on
open ground as 5-10m long, 1-2m wide, and 0.5-
1.0m high piles. The top of each pile is covered
with cattle dung. After a few days, the piles are
raked and turned upside down for cooling and
aeration. In about 4-6 weeks, the compost gets
stabilized.

25. (c) Mechanical composting
•In this method, putrescible solid wastes are
converted to compost by mechanical devices in
composting plants. The whole process is completed
in about 3-6 days. Mechanical composting involves
segregation, shredding (pulverization) and
stabilization of the waste, and the preparation of
the stabilized mass for marketing.

26. (d) Vermicomposting
• Vermicomposting is the composting of solid organic waste using
some species of earthworms. It is much faster than trench
composting and open window composting. The compost, produced
by the breakdown of the organic debris by earthworms, is known
vermicompost.
• The earthworms commonly used in vermicomposting include
Perionyx excavates, P. sansibaricus, Dendrobaena veneta,
Dichogaster spp, Eudrilus eugeniae, Eisenia fetida, E. andrie,
Lumbricus rubellus, etc.
• Vermicomposting can be carried out in bins, tanks, or other suitable
containers. The solid waste is first allowed for natural primary
decomposition. Then, it is filled in vermicomposting containers.

27. •Now, earthworms are released to the containers.
They gradually bring about composting. The whole
process is completed in about 60-75 days.
•Vermicomposting is a technology for the disposal
of domestic garbage, solid municipal waste and
non-toxic solid and liquid industrial wastes, for the
production of non-chemical and non-synthetic
manure, and also for keeping the environment
clean and healthy.

28. (vii) Dumping of solid waste into sea
• In this method of waste disposal, solid waste is dumped into the
deep open sea, 16 to 20 km away from the sea shore. Though this
method is simple and cheap, it has the following disadvantages
also.
• (i) Lighter components of the waste float, drift and spread and
often return to the shore along with high tide. This pollutes the
beach.
• (ii) During monsoons and stormy weather, when the sea is
dangerously rough, off- shore transportation of the waste is very
difficult.

29. II. Disposal of hazardous wastes
• The disposal of hazardous wastes is a highly expensive affair. It involves an
appropriate combination of several methods and requires maximum
precautions. Some of the methods used in it are the following:
• (i) Safe landfilling and deep-well injection.
• (ii) Solidification, chemical oxidation, incineration, pyrolysis, etc.
• (iii) Preliminary neutralization of acidic, alkaline, oxidizing, or reducing
wastes, prior to final disposal.
• In India, the management of hazardous wastes is regulated by the
Hazardous wastes (Management and Handling) Rules (1989) and
Amendment Rules, 2000 and 2003.

30. III. Disposal of biomedical wastes
•The disposal of biomedical wastes is to avoid their dispersion
in the environment and also to avoid human exposure to
them. It mainly involves the transformation of the waste into
non-hazardous residues by appropriate treatment.
•Prior to storage, transportation and treatment, the wastes
have to segregated in separate containers taking into account
their nature and the existing statutory regulations.
•The loaded containers must be labelled and then transported
for treatment and disposal only in those vehicles which are
authorised for the purpose by competent authorities.

31. •The waste treatment methods include incineration, chemical
disinfection, auto- claving, microwave irradiation, shredding,
etc. The disposal may be done by sanitary landfilling or
burying inside the premises.
•The criteria for the selection of the method include
availability of technology, qualified personnel and sufficient
space, prevail- ing regulations, nature and quantity of the
waste, environmental aspects, and so on.
•The Govt. of India have promulgated the Biomedical waste
(Management and Handling) Rules 1988, stipulating some
guidelines for biomedical waste manage- ment.
•As per this law, it is mandatory that any health care activity,
which may generate biomedical waste, should get the prior
legal sanction from the Pollution Control Board.

33. E-WASTE MANAGEMENT
• E-Wastes, or electronic wastes, are the wastes generated from the
broken, defective, unwanted, or outdated electronic devices,
appliances and accessories which are no longer useful for their
intended purposes.
• Hence, they are left for disposal, or for recycling, recovery and
reuse.
• They include a wide range of obsolete articles, such as computers,
laptops, UPS, printers, CDs, pen drives, connecting cables, hand-held
cellular phones, radios, stereos, battery cells, electronic toys,
refrigerators, air conditioners, telephones, music systems, and so on.

34. •E-wastes are the by-products of electronic revolution and the
spectacular and mercurial growth of electronics and electrical
industries. In these industries, new gadgets and sophisticated
models ap- almost every day and the old ones are discarded
as junk.
•These industries ensure their steady and rapid growth by
making their existing products obsolete as fast as possible.
Some of the old ones may still be in good working condition,
but they cannot be used for want of spare parts.
•This results in the piling of e-wastes, putting a growing
menace and major challenge to the environment.

37. •The composition of e-wastes is highly diverse and
product-specific. They include both toxic and useful
materials. In general, the major toxic components in-
clude ferrous and non-ferrous metals, flame retardants,
plastics, glass, wood, ply- wood, printed circuit boards,
ceramics, rubber, and the like.
•The non-ferrous hazard- ous metals include copper,
zinc, aluminium, silver, gold, platinum and palladium.
•The presence of mercury, arsenic, cadmium, selenium,
chromium, etc is also common.

38. •The toxic materials in the e-wastes contaminate air, soil and
ground water and pose serious health hazards. The hazardous
materials of e-wastes can have harmful effects when they are
burnt or buried.
•Landfilling of e-wastes may lead to the leaching of some of
them, such as lead, to the ground water.
•Their crushing or burning may release toxic fumes to the
atmosphere.
•Some developed countries export their e-wastes to
developing countries.
•Countries like China and India import e-wastes and recycle
them.

39. Environmental impacts of e-wastes
• It has been roughly estimated that nearly 56 million tonnes of e-
wastes have been generated world wide in 2010. In 2012, it rose to
around 65 million tonnes.
• At this rate of increase, it might have crossed the 160 million tonnes
mark by this time. This trend is on steady increase in the digital
revolution era, with a corresponding in- crease in environmental risk.
• It is a shocking revelation that nearly 40% of the lead and 60% of the
heavy metals (copper, iron, aluminium, gold, chromium, mercury),
found in landfills, come from e-wastes and 30% of the e-wastes
consists of non- degradable or very slowly degradable plastics.

40. • E-wastes pollute air and ground wa- ter and contribute to the acidification of soil.
They may inflict severe damages on vital organs, nervous system and immune
system. Radiation effects from e-wastes and exposure to heavy metals pose
serious health hazards.
• The contamination of air, soil and water, with severe impact on human health is
mainly by the following agents.
• (i) Lead and cadmium from circuit boards.
• (ii) Lead oxide and cadmium from monitor cathode ray tubes.
• (iii) Mercury from switches and flat screen monitors.
• (iv) Cadmium from computer batteries.
• (v) Lead and antimony oxide from the brominated flame retardants of plastic cas-
ings, cables, etc.
• (vi) Dioxins and furans, released during the burning of cables and casings.

41. Management and disposal of e-wastes
• E-waste management is very difficult and highly expensive due to the
wide range and high complexity of their component materials.
• So, profitable recycling and the safe disposal of e-wastes are very
serious problems in most countries, especially in developing
countries.
• The issue is further complicated by the export of e-wastes from
developed countries to developing countries in the name of free
trade for the recycling of the valuable materials contained in e-
wastes.
• Thus, for the developing countries e-waste is a burning
environmental problem, and for developed countries it is a business
opportunity.

42. • Crushing and landfilling are not safe methods for the disposal
of e-wastes.
• Currently, reduction and re-cycling seems to be the most
appropriate strategy for deal- ing with e-wastes. It involves
the decontamination, dismantling, pulverization, shred- ding
or density separation, and re-cycling of e-wastes.
• The bulk of accumulating e-wastes can be reduced by
prolonging the life of the products through eco-friendly
designing, best-suited for repair, re-use, recycling and
upgradability.
• Product designers should ensure that the products are
repairable, re- usable, re-cyclable, re-furnishable and
upgradable.

43. •They must also ensure that the materials used are
less toxic and easily recoverable for their easy
recovery and close- loop recycling.
•Recovery of metals, plastics, glass, and other
materials from e-wastes considerably reduces the
potential hazards of e-wastes.
•For the successful imple- mentation of this e-
waste management strategy, manufacturing
companies must com- pulsorily adopt the policy of
product take-back from the end users for
replacement, repair, recovery, or recycling.

44. Components of e-waste management
• E-waste management consists of the following two major
components.
• (a) E-waste collection, sorting and transportation.
• (b) E-waste recycling which involves the dismantling and recovery of
valuable materials and the disposal of the unsalvageable dismantled
parts.
• The collection systems should collect e-wastes from the right places
in the right time. The collected wastes should be dismantled and
recycled only at authorised centres that are provided with the
required facilities to deal with the wastes in an environmentally
sound manner as per national and international guidelines.

45. •The recovery of metals, plastics and other valuable materials
from e-wastes en- ables to bring them back to the
production cycle.
•This makes e-waste recycling a profitable and lucrative
business.
•Perhaps the best way of e-waste management is the
adoption of the principle of "extended producer
responsibility (EPR)".
•By applying this principle, all the links of the producer-
product-user chain, namely the producers or manufactures,
suppliers and consumers, are made to share the
responsibility of minimizing or neutralising the
environmental impact of a product.

46. •The manufacturer has to decide or influence the product
design, select the ideal raw materials, choose the most
appropriate manu-facturing process or technology, and buy
back the product after its end use for safe recycling or
disposal.
•All these are aimed at making the process and product least
harmful and most environment-friendly. Suppliers should see
that they provide the manufacturers only with non-toxic and
environment-friendly materials and components.
•Consumers has to very carefully choose and purchase only
environment- friendly products, opting out the others. They
must also see that the products are used and are finally
disposed in a most environmentally ideal manner.

47. E-waste laws in India
•It has been roughly estimated that India generates
nearly 350,000 tonnes of e- wastes and imports about
50,000 tonnes every year. To regulate all the processes
related to e-wastes, E-Waste Rules came into effect
from 01.05.2012 onwards, empowering the State
Govts. to grant licences.
•According to these rules, manufactures are accountable
for the quality and safety of their products throughout
the produc- tion-distribution-consumption-disposal
cycle.

48. •A producer has to manage the end of the life of his
products in a safe and environment-friendly
manner.
•The local self government institutions are
authorised to collect non-branded "orphan" e-
wastes and send them to authorised dismantlers or
recyclers.
•Manufacturing companies have to organize their
own buy-back or take-back mechanisms and
machineries for the final environment-friendly
disposal of their products to reduce e-waste
accumu- lation.