Pollution and Its Control

7/26/2019 Pollution and Its Control

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SubmittedBy :

Mohd. SahilXIIth

Submitted To :Mr. Mohit

Kumar Premi

Subject :Subject :BiologyBiologySession :Session : 2013-142013-14


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DECLARATI!DECLARATI!

T"is is to #o$ gene$%l &ecl%$%tion

'u$'oses only t"%t %ll $ele(%nt )o$*

'e$t%ining to '$esente& +ini%tu$e

'$oject on :,Pollution & its Control,

"%s been solely co+'lete& by +e

Besi&es un%(oi&%ble lin*s to ce$t%in

$e#e$ences. t"e o(e$%ll )o$* is

%bsolutely o$igin%l in n%tu$e

/o"& S%"il/o"& S%"il


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CERTIICATECERTIICATE

T"is is to ce$ti#y t"%t %ll $ele(%nt )o$*

'e$t%ining to '$esente& +ini%tu$e

'$oject on :

"Pollution & its Control")%s co+'lete& by /o"& S%"il un&e$

+y gui&%nce e "%s &one "%$& )o$* to

co+'lete t"e '$oject is )o$* is

%bsolutely o$igin%l in n%tu$e

/$ /o"it u+%$ $e+i/$ /o"it u+%$ $e+i


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BIDATA

Name : Mohd. Sahil

Class / Se : IIt"

Session : 2013-14

Sub!et : Biology

oll No. :

To#i : "Pollution & itsControl"

Sub!et Teaher : /$ /o"it u+%$

$e+i

Teaher$s Si%n :

Prini#al$s Si%n :


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emars :

AC!5LED6E/E!TAC!5LED6E/E!Tisto$y o# %ll g$e%t )o$*s is to )itness t"%t no

g$e%t )o$* )%s e(e$ &one )it"out eit"e$ t"e

%cti(e o$ '%ssi(e su''o$t o# % 'e$son7s

su$$oun&ings %n& one7s close 8u%$te$s T"us it isnot "%$& to conclu&e "o) %cti(e %ssist%nce #$o+

senio$s coul& 'ositi(ely i+'%ct t"e e9ecution o# %

'$oject I %+ "ig"ly t"%n*#ul to ou$ le%$ne&

#%culty /$ /o"it u+%$ $e+i. #o$ "is %cti(e

gui&%nce t"$oug"out t"e co+'letion o# '$oject

L%st but not t"e le%st . I )oul& %lso )%nt to

e9ten& +y %''$eci%tion to +y '%$ents %s )ell %s

t"ose )"o coul& not be +entione& "e$e but "%(e

)ell 'l%ye& t"ei$ $ole to ins'i$e +e be"in& t"e

cu$t%in

/o"& S%"il


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Ancient cultures

Air pollution has always accompanied civilizations. Pollution started

from the prehistoric times when man created the first fires.

According to a 1983 article in the journal Science !soot found onceilings of prehistoric caves provides ample evidence of the high

levels of pollution that was associated with inade"uate ventilation of

open fires.! #he forging of metals appears to $e a %ey turning point

in the creation of significant air pollution levels outside the home.

&ore samples of glaciers in 'reenland indicate increases in pollution

associated with 'ree% (oman and &hinese metal production $ut at

that time the pollution was comparatively less and could $e handled

$y nature.

Official Acknowledgement

)ing *dward + of *ngland $anned the $urning of sea,coal $y

proclamation in -ondon in 1/ after its smo%e $ecame a

pro$lem. 0ut the fuel was so common in *ngland that this earliest of

names for it was ac"uired $ecause it could $e carted away from

some shores $y the wheel$arrow. Air pollution would continue to $e

a pro$lem in *ngland especially later during the industrialrevolution and etending into the recent past with the 'reat Smog

of 192. -ondon also recorded one of the earlier etreme cases of

water "uality pro$lems with the 'reat Stin% on the #hames of 1828

which led to construction of the -ondon sewerage system soon

afterward.

+t was the industrial revolution that gave $irth to environmental

pollution as we %now it today. #he emergence of great factories and

consumption of immense "uantities of coaland other fossilfuels gave rise to unprecedented air pollution and the large volume

of industrial chemical discharges added to the growing load of

untreated human waste.&hicago and &incinnati were the first two

American cities to enact laws ensuring cleaner air in 1881. ther

cities followed around the country until early in the 4th century

when the short lived ffice of Air Pollution was created under the

5epartment of the +nterior. *treme smog events were eperienced

$y the cities of -os Angeles and 5onora Pennsylvania in the late1964s serving as another pu$lic reminder.


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Modern Awareness

Pollution $ecame a popular issue after

7orld 7ar ++ due to radioactive fallout

from atomic warfare and testing. #hen anon,nuclear event #he 'reat Smog of

192 in -ondon %illed at least 6444

people. #his prompted some of the first

major modern environmental legislation

#he &lean Air Act of 192.

Pollution $egan to draw major pu$lic attention in the nited States

$etween the mid,1924s and early 19/4s when &ongress passed

the :oise &ontrol Act the &lean Air Act the &lean 7ater Act and

the :ational *nvironmental Policy Act.

#he major forms of pollution are listed $elow along with the

particular contaminant relevant to each of them;

Air pollution:- the release of chemicals and particulates into

the atmosphere.&ommon gaseous

pollutants include car$on monoide

sulfurdioide chlorofluorocar$ons

and nitrogen oides produced

$y industry and motor vehicles.

Photochemicalozone and smog are

created as nitrogen oides

and hydrocar$ons react to

sunlight. Particulate matter or fine dust is characterized $y

their micrometre size P?14 to P?.2.

Light pollution:-includes light trespass over illumination and

astronomical interference.

Littering:- the criminal throwing of inappropriate man,made

o$jects unremoved onto pu$lic and private properties.

Noise pollution:- which encompasses roadway noise aircraft

noise industrial noise as well as high,intensity sonar.

Soil contaminationoccurs when chemicals are released $y spill

or underground lea%age. Among the most significant soil


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contaminants are hydrocar$ons heavy metals ?#0*

her$icides pesticides and chlorinated hydrocar$ons.

Radioactive contamination resulting from 4th century

activities in atomic physics such as nuclear power generationand nuclear weapons research manufacture and deployment.

Thermal pollution is a temperature change in natural water

$odies caused $y human influence such as use of water as

coolant in a power plant.

isual pollution which can refer to the presence of

overhead power lines motorway $ill$oards scarred

landforms open storage of trashmunicipal solid waste or space de$ris.

!ater pollution $y the discharge of wastewater from

commercial and industrial waste

into surface waters@ discharges of untreated domestic sewage

and chemical contaminants such as chlorine from treated

sewage@ release of waste and contaminants into surface

runoff flowing to surface waters @ waste disposal and leaching

into ground water@ eutrophication and littering.

Sources of air pollution:

#he sources of air pollution can $e natural or man made.

i> :atural Sources

Bolcanic eruptions emitting poisonous gases

5ecay of vegetation

?arsh gases

Pollen grains

=orest fires


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ii> ?an made Sources

+ncrease in pollution

5eforestation

=ossil fuel com$ustion

Behicular emissions

+ndustrialization

se of pesticides insecticides in agriculture

*plosives used in wars

#ypes of Air Pollutants;

#he undesira$le component in the atmosphere causing pollution is

referred to as pollutant. Pollutant can $e classified on the $asis of

origin and physical state. n the $asis of origin pollutants are of

two types;

a> Primary pollutant; it is the product of natural events and human activities added directly to air.*amples include & : S and hydrocar$ons.

$> Secondary pollutant; it is formed $y the interaction of primary

pollutants with each other or with normal components of the

air. *amples include ozone photochemical smog etc.

n the $asis of physical state pollutants are of two types;

i> 'aseous pollutants; these are the gases which mi with the air

without settling down. 'aseous pollutants include & S

& S3 : and hydrocar$ons.

ii> Particulate pollutants; it comprises of finely divided solids or

li"uids. #hese include dust smo%e smog lead mercury

cadmium and as$estos.

Some &ommon Air Pollutants;


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1. &ar$on ?onoide , +t is a colourless odourless tasteless

gas that is $y far the most a$undant of the air pollutants. a

Source, +t is produced due to;

+ncomplete com$ustion of fuels

Automo$ile ehausts

+ndustrial operation

& is also produced through natural processes such as volcanic

activity natural gas and marsh gas emissions.

$. Sin% for & , Sin% is a system which a$sor$s the pollutant

there$y nullifying its harmful effect. A large mass of & isgenerated and also there is continuous increase in & emissions

within recent years. So it is o$vious that the amount of & in the

atmosphere should also increase. 0ut it has $een found that the

amount of & in the atmosphere remains relatively constant

suggesting that a sin% or scavenging process also eists in the

atmosphere. #he micro organisms present in the soil act as a major

sin% for &.A significant amount of & is converted into & $y

these microorganisms.

c. *ffects of & , #he levels of & present in the ur$an air do not

affect significantly the plants and materials. Cowever these levels

adversely affect human health. +n ur$an areas the soil availa$le is

insufficient to act as a sin% there$y increasing the level of &

$eyond permissi$le limits. & interferes with the $loodDs a$ility to

carry oygen to different parts of the $ody. #he oygen com$ines

with hemoglo$in which is also %nown as oygen carrier to form

oyhemoglo$in. #his oyhemoglo$in travels to different parts of the

$ody cells where it gives oygen to the cell and ta%es up &

through the lungs. +f & is inhaled it readily $inds to hemoglo$in to

form car$oyhemoglo$in and $lood carries less oygen to various

parts of the $ody. =ortunately & is removed from the $lood stream

when clear air is cleaned.

d. &ontrol of &, &ontrol of pollution caused $y & can $e

achieved through the following techni"ues;


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?odification of engine design; A low fuel,air ratio reduces :

emissions $ut increase & emissions. So engine design should

design should $e modified so that right proportion of oygen is

maintained for complete oidation of car$on and hydrogen to &

and C4 respectively.

=uel modification; #he fuels which release lesser amount of &

are recommended to $e used. #hese fuels include natural gas

methane and $lends of light hydrocar$ons.

#reatment of ehaust gases; #wo stag catalytic converters are

used to lower the pollution from ehaust gases. +n the first stage

: are reduced to : and :C3 in the presence of catalyst such as

Pt Pd and (uthenium in the presence of reducing gas such as &. in

second stage oidizing catalysts of no$le metals supported on

ceramic materials are used which ensure oidation of & and &.

. ides of :itrogen , A num$er of oides of nitrogen such

as : : : :3 and :2 are introduced into the

atmosphere due to natural as well as human activity. ut of these

the two oides : and : are responsi$le for pollution and are

considered as the pollutants and are represented $y :. : isreddish $rown in color having pungent smell and is suffocating

whereas : is colorless and odorless gas.

a. Source, #he sources of : include;

:atural; during lightening discharge : and in air com$ine

to form :

?an,made sources;

: is formed when : and at very high temperatures. #his

temperature is usually attained during com$ustion of fossil fuel in

air.

: is also produced in chemical industries as $y products

such as in coal $ased power plants sulphuric acid and nitric acid

manufacturing plants

$. Sin% for : , #he : and : undergo various processes inthe atmosphere leading to the formation of C:3. #hus : :


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pollutants gets precipitated as nitrates during rainfall. zone plays a

significant role in these photochemical reactions. +n presence of

volatile organic compounds : reacts with water in presence of

oygen resulting in formation of nitric acid. C:3 comes down from

the atmosphere to the surface of earth in form of acid rain. Cere it

reacts with $ases such as ammonia lime etc. to form nitrates.

c. *ffects , Almost all the : emissions are in the form of :

which has no %nown adverse health effects at the concentrations

found in atmosphere. Cowever : can oidize to : which in

turn may react with hydrocar$ons in the presence of sunlight to

form photochemical smog. #he C:3 formed $y : causes acid

rain which has corroding effect on mar$le and the metallicstructures. +t decreases pC of the soil affecting its fertility.

d. &ontrol of : , #he control measures include;

?odifying the engine design; (educing the amount of ecess

air for com$ustion in air helps in controlling : emissions. #he

$urners are so modified that the fuel and the air mi more slowly

reducing the intensity and temperature of com$ustion.

Scru$$ing the flue gases; #he flue gases are scru$$ed with

CS6 in a scru$$er. #he reaction product thus o$tained is then

decomposed to nitric acid and :.

Selective catalytic reduction; #he selective catalytic reduction

can $e achieved through &C6 :C3 and &. #he : is added to the

ehaust gases and the miture is passed over a fied $ed catalyst

such as copper oide.

+t is interesting to note that the air pollution control methods also

re"uire modification of com$ustion methods. 0ut the methods that

improve & emissions tend to ma%e emissions of : pro$lem

worse and vise versa.

E *nvironmental *ffects of Air Pollution;

#he air pollutants have a great impact on our environment. #hey are

posing a threat to earthDs general environment. #he major effects

are;


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1. Photochemical Smog;

FSmogD is the com$ination of two words Fsmo%eD and FfogD. Smog is of

two types;

-ondon Smog;

#he smog from S particulates and humidity is %nown as -ondon

Smog. #his type of smog caused death of around 6444 people in

-ondon in 192 hence the name. #he miture of smo%e S and

fog is chemically a reducing miture and hence also termed as

reducing smog.

-os Angeles =og ; it results from the

photochemical reactions of the atmosphere. +t is the atmospheric

haze that is formed near many large cities and is due to the action

of sunlight on hydrocar$ons and the nitrogen oides. #his type of

smog was first o$served in -os Angeles in 1924.

. Acid (ain;

npolluted rain water is slightly acidic due to the presence of & in

the atmosphere. & com$ines with the water to form a wea%

solution of car$onic acid with a pC of a$out 2.. Cowever in polluted

environments the rain passes through an atmosphere polluted with

oides of sulphur and nitrogen. #he falling rain reacts with these

oides to form a miture of sulphuric acid and nitric acid and water.

#his is %nown as acid rain. Acid (ain =ormation;

#he oides of sulphur react with moisture to form CS6 in steps;

24 G H S3

243 G C H CS6

Similarly oides of nitrogen form C:3

: G 3 H : G

: G 3 H :3 G

: G :3 H :2

:2 G C H C:3


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#hese acids along with C&- gives rise to the acid rain.

3. 'reen Couse *ffect;

#he green house effect is the rise in temperature that the earth

eperiences $ecause certain gases in the atmosphere a$sor$ energy

from the sun. 7ithout these gases heat would escape $ac% into

space and the earthDs average temperature would $e a$out 4I

colder. #he phenomenon has $een named green house effect as it is

similar to heat trapping effect of the glass walls in a horticulture

green house.

a. #he Process , #he earth receives a tremendous "uantity of

radiant energy from the sun a$out 34J of which is reflected $ac%into space $y the earthDs atmosphere. #he remaining energy passes

through the atmosphere to the earthDs surface. Some of the energy

is a$sor$ed $y plants to drive photosynthesis and some $y the

oceans to evaporate water $ut most is a$sor$ed $y soil roc% and

water to increase the temperature of the earthDs surface. #his

energy is in turn radiated from the heated surface mainly as infrared

radiation often called heat radiation. Cowever only a small portion

of this energy ma%es it $ac% into the space. #he majority of infraredradiations are a$sor$ed the green house gases present in the

atmosphere. A net amount of thermal energy is retained $y the

earth that ma%es it warmer than it would $e without these gases in

the atmosphere.

6. zone -ayer and its 5epletion;

zone is a very small part of our atmosphere $ut its presence is

nevertheless vital to human well$eing. ?ost ozone resides in the

upper part of the atmosphere called stratosphere etending from 1

%m to 64 %m. the high concentration of ozone in the ozone layer

shields us from the harmful ultraviolet light from sun. a *ffect of

zone -ayer , zone protects us from harmful B rays a$sor$ing

these radiations. +n a$sence of ozone layer these rays would reach

earth and cause;

S%in caner

5amage to the plants


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Sun $urns

?elanoma

-eu%emia

&ataracts etc.

#he a$sorption of B radiation $y ozone is a source of heat in

stratosphere. As a result ozone plays a %ey role in maintaining the

temperature structure of earthDs atmosphere.

$. 5epletion of zone , zone depletion has $een found to occur

through the following types of compounds;

&hloroflouro car$ons

:itric oide

(eactive hydroyl radicals

Atomic oygen

c. *ffects of depletion of zone;

#he eisting ozone layer screens out more than 99J of

incoming B radiations. #he small fractions gets through is %nown

to cause sun$urn s%in cancer and various %inds of damage to

animal and plants.

#he genetic material 5:A has the capacity to a$sor$ B

radiations which may cause various disruptive defects.

2J depletion in ozone produces 14J increase in radiations

reaching the earth according to an estimate.

*posure to B radiation damages the cornea and lens of the

eye causing $lindness.

0. 7ater Pollution;

7hen toic su$stances enter la%es streams rivers oceans and

other water $odies they get dissolved or lie suspended in water.

#his results in the pollution of water where $y the "uality of waterdeteriorates. #he word polluted water is defined as the deterioration


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of physical chemical and $iological properties of water $rought

mainly $y human activities and natural resources and which cause

harmful effect on human and a"uatic life.

E Sources of water pollution , 7ater pollution is caused $yhuman as well as natural activities.

i> :atural Sources , #hese include decomposed vegeta$le

animal and weathered products which are $rought into main water

resources.

ii> Cuman Activities , #hese include domestic as well as industrial

pollution;

a. 5omestic; #he release of huge "uantities of municipal and

domestic wastes through the drains into the rivers and canals is the

major cause of pollution. #he domestic waste water contains human

faeces %itchen wastes organic water that provides nutrition to

fungi and $acteria.

$. +ndustrial; #hese include effluents from factories refineries

and a num$er of chemical industries. 7ater gets polluted $y acids

al%alis detergents copper zinc lead mercury etc. which areconstantly added to water $y industrial effluents.

c. Apart from these two the water is also polluted through

agricultural discharge such as pesticides insecticides fertilizers etc.

$esides these $acteria algae virus also cause water pollution.

E &lassification of 7ater Pollutants;

#he pro$lem of water pollution due to discharge of domestic and

industrial waste into water has already $ecome a serious pro$lem in

the country. #o aid in the systematic discussion of water pollutants

they have $een classified into nine categories;

1. ygen demanding wastes

. Pathogens

3. Synthetic organic compounds

6. Plant nutrients


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2. +norganic chemicals and minerals

. Sediments

/. (adioactive su$stances

8. #hermal discharges

9. il

1. ygen 5emanding 7astes;

5issolved oygen is essential for sustaining the plant and

animal life in any a"uatic system. 7arm,water fishes re"uire a

minimum 5 level of 2 mgK-. if 5 level drops $elow the levelnecessary to sustain normal life then water is classified as polluted.

#he amount of 5 in water is reduced $ecause of oygen

demanding wastes. #hese are su$stances that oidize in water

reducing the amount of 5. #hese include organic su$stances

contained in municipal waste water or in effluents from certain

industries. #he oygen demanding wastes are oidized $y $acteria

or micro organisms consuming 5 in water to & and water. #hese

su$stances produce undesira$le odor tastes and reduce the

accepta$ility of water as domestic supply.

#here are several measures f oygen demand commonly used;

0iological ygen 5emand ; 05 is the amount of

oygen re"uired $y microorganisms to $iologically degrade the

wastes. +t is the most important measure of the strength of organic

pollution

&hemical ygen 5emand ; &5 is the amount ofoygen needed to chemically oidize the wastes.

1. Pathogens , #hese are disease causing organisms that grow

and multiply within the host. 7ater is potential carrier of pathogenic

microorganisms. #hese pathogens are carried into the water $odies

$y sewage and wastes from farm and various industries.

&ontaminated water caused $y poor sanitation can lead to $oth

water $orne and water contact diseases. 7ater $orne diseases are

those ac"uired $y ingestion of pathogens not only in drin%ing water


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$ut also from the water that ma%es it to personDs mouth from

washing food utensils and hands. *amples are cholera typhoid

etc. 7ater &ontact diseases do not re"uire that the individual ingest

the water. Lust contact with the water causes the disease. =or

eample $ilharzia is the most common water contact disease in the

world.

. Synthetic rganic &ompounds , #hese include pesticides

synthetic organic chemicals and detergents. #hese compounds are

not $iodegrada$le and persist for longer periods. ?ost of these are

accumulative toic poisons and ultimately reach o$jectiona$le levels

in water. Pesticides cover a range of chemicals that %ill organisms

that human consider undesira$le. #hese enter the water $odies fromrun off from agricultural lands waste discharge $y pesticides

manufacturers and $y other means. 0ecause of their world wide

usage nearly all the rivers and oceans of the world contain

pesticides residue. 5etergent means cleansing agent. #he $asic

active ingredient in detergents is surfactant or surface active agent

with contains hydropho$ic and hydrophilic groups. Surfactants

decrease the surface tension of water so that they can penetrate the

surface and interstices of the o$ject to $e cleaned. #e remainder

comprises of polysulphate salts called $uilders and other

ingredients. Surfactants concentrations as low as 1ppm produce

foam in rivers and in sewage treatment plants. Although these

concentrations are non,toic to humans their presence gives off

taste of drin%ing water. #he detergent $uilders pose greater pro$lem

today. #he polyphosphates $uilders are released into water and act

as plant nutrients. #he etensive growth of algae consumes most of

dissolved oygen from water.

3. Plant nutrients , :utrients are chemicals such as nitrogen

phosphorus car$on sulphur calcium potassium iron etc. that are

essential to growth of living things. Cowever in terms of water

these nutrients are considered as pollutants@ when their

concentrations are sufficient allow ecessive growth of a"uatic

plants particularly algae. 7hen these algae die and decompose

they add undesira$le odor and o$jectiona$le taste of water. =urther

the decaying of organic matter oidizes and leads to reduced 5

levels. #he gradual accumulation of silt and organic matter is %nown


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as eutrophication. Cigh concentration of nutrients poses the pro$lem

of eutrophication $ut also when found in drin%ing water it is a

serious health hazard.

6. +norganic &hemicals and ?inerals , #his include inorganic saltsmineral acids and finely divided metal or metal compounds trace

elements cyanides organo,metallic compounds etc. they are added

to the water $odies through municipal and industrial waste water

and mine run off.

a. Acid ?ine 5rainage , +t is a source of increasing acidity in

natural water acid rain also adds to it. #he mining of sulphur

$earing ores containing lead zinc and copper lead to acid drainage.

&oal mines discharge is also a cause of acid mine drainage.

$. Solu$le Salts , #he salts or solids passing through water on its

way to sea include cations such as sodium calcium potassium

magnesium and anions li%e chlorides sulphates and $icar$onates.

#he measure of salinity is concentration of total dissolved solids

.

c. Ceavy ?etals , +t refers to metals with specific gravity greater

than 6 or 2. ?etals may $e inhaled or digested and have adverse

effects on the $ody. &admium lead and mercury are nephrotoic

metals.

2. Sediments , #hey include soil sand and mineral particles

washed into a"uatic environment $y storms and flood waters. #hey

are sources of organic and inorganic matter which reduces the

storage capacity. #his decreases evolution of oygen and hence

cannot support a"uatic animals.

. (adioactive Su$stances , #hey enter a"uatic system through

the use of naturally occurring or artificially produced radioactive

materials. #hese pollutants enter the water system through;

?ining and processing of ores

:uclear power plants

-ea%age from underground nuclear detonations


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(adioisotopes in medicine etc.

/. #hese su$stances can enter human $ody through food and

water and cause cancer eye cataract etc.

a. #hermal 5ischarges;

#he used coolant water in industries id directly discharged into

water $odies which increases their temperature. #his is thermal

pollution. (ise in temperature decreases 5 content which affects

the a"uatic life.

$. il;

+t is added to water $odies from industries as effluents oil refineriesstorage tan%s and automo$ile waste oil. il $eing insolu$le in water

floats over it. +t may penetrate the feathers of $irds such that they

find difficulty in floating and flying. #hey may ingest it and die.

c. Bolatile rganic &ompounds;

#hey are volatile solvents used in industries. #hey are toic and

cause harm when present in drin%ing water. Some of the B&s are;

Binyl chloride

# etrachloroethylene

&ar$ontetrachloride

#richloroethylene

7aste 7ater treatment Process; Availa$le waste water

treatment processes can $e classified as;

Physical

&hemical

0iological

#he waste water treatment processes are generally grouped

according to water "uality they are epected to produce


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1. Primary #reatment , +t utilizes physical processes li%e

screening to remove a portion of pollutants that settle or float.

Pretreatment; +t consists of screening and grit removal.

Screening removes large floating o$jects which are disposed off.#hen water passes into grit cham$er where velocity of water is

reduced.

Sedimentation; =rom grit cham$er sewage passes into

primary settling tan% called sedimentation $asin. +t clarifies

suspended solids and 64J of organic matter.

. Secondary #reatment , #he purpose here is to remove organic

matter and is $ased upon $iological process similar to natural$iodegradation $y aero$ic $acteria. #hey include;

&oagulation of colloidal matter

idation of organic matter

&onversion of nitrogeneous matter to ammonia and finally to

nitrites and nitrates

Anaero$ic digestion of sludge

3. #ertiary #reatment , +t improves the "uality of effluent further.

+t includes removal of;

Suspendedsolids

0acteria

5issolved organic solids

#oics

:utrients

Some of the techni"ues are;

?icro,staining; +t removes the solid wastes that get retained

on fa$ric of filter media

(emoval of 5issolved Solids; +t can $e done $y adsorption ofsolu$le organics on activated car$on solvent etraction ion,


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echange reverse osmosis and

chemical precipitation through lime etc.

(emoval of :utrients; it includes removal of nitrogen

and phosphorous which may $e present asorthophosphates $y alum.

(emoval of $acteria; 0y retaining effluents in maturation

pond for specified period of times.

&. Soil Pollution;

E Sources; Soil pollution is degradation of soil mainly through

human misuse. #he human influences include;

+ndustrial waste; this is disposed into the soil and poses a

detrimental effect.

5isposal of solid wastes; this is accumulation of lead

particles from automo$ile ehausts gar$age containing

plastics etc.

Agricultural practices; this is due to fertilizers and use of

pesticides.

0iological agents; this is through ecreta of humans $irds

and animals.

Soil erosion; nutrients for supporting vegetation are wiped

off.

E *ffects; Soil pollution adds a num$er of chemicals to it and

these are transferred into humans through food chains.

?etallic contaminants destroy the $eneficial micro organisms

in soil and hence effect plant growth. *cessive use of

fertilizers ma%es soil al%aline or acidic. se of pesticides ma%es

soil contaminated and is also persistent. #he most dangerous

pesticide 55# is now $anned as it accumulates in the food

chain.

E &ontrol; #hey include method to reduce and dispose soil

wastes. #his can $e achieved through following ways,


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Proper dumping of soil wastes

0anning of highly toic and persistent chemical pesticides

Proper awareness of the masses

+ncreased crop rotation

(ecycling of the waste

Plantation of trees to a larger etent.

"uman health

verview of main health effects on humans from some common

types of pollution.

Adverse air "uality can %ill many organisms including humans.

zone pollution can cause respiratory disease cardiovascular

disease throat inflammation chest pain and congestion. 7aterpollution causes approimately 16444 deaths per day mostly due

to contamination of drin%ing water $y untreated sewage in

developing countries. An estimated 244 million +ndians have no

access to a proper toilet and 284 +ndians die of water,related

pollution every day. :early 244 million &hinese lac% access to safe

drin%ing water. A 414 analysis estimated that 1. million people

died prematurely in a year in &hina $ecause of air pollution. +n 44/

it was estimated that in +ndia air pollution is $elieved to cause


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2//44 fatalities. Studies have estimated that the num$er of

people %illed annually in the S could $e over 24444.

il spills can cause s%in irritations and rashes. :oise pollution

induces hearing loss high $lood pressure stress and sleepdistur$ance. ?ercury has $een lin%ed to developmental deficits in

children and neurological symptoms. lder people are majorly

eposed to diseases induced $y air pollution. #hose with heart or

lung disorders are at additional ris%. &hildren and infants are also at

serious ris%. -ead and other heavy metals have $een shown to

cause neurological pro$lems. &hemical and radioactive su$stances

can cause cancerand as well as $irth defects.

#erspectives

#he earliest precursor of pollution generated $y life forms would

have $een a natural function of their eistence. #he attendant

conse"uences on via$ility and population levels fell within the

sphere of natural selection. #hese would have included the demise

of a population locally or ultimately species etinction. Processes

that were untena$le would have resulted in a new $alance $rought

a$out $y changes and adaptations. At the etremes for any form of

life consideration of pollution is superseded $y that of survival.

=or human%ind the factor of technology is a distinguishing and

critical consideration $oth as an ena$ler and an additional source of

$yproducts. Short of survival human concerns include the range

from "uality of life to health hazards. Since science holds

eperimental demonstration to $e definitive modern treatment of

toicity or environmental harm involves defining a level at which aneffect is o$serva$le. &ommon eamples of fields where practical

measurement is crucial include automo$ile emissions control

industrial eposure .#he solution to pollution is dilution! is a dictum

which summarizes a traditional approach to pollution management

where$y sufficiently diluted pollution is not harmful. +t is well,suited

to some other modern locally scoped applications such as

la$oratory safety procedure and hazardous material release

emergency management. 0ut it assumes that the dilutant is in


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virtually unlimited supply for the application or that resulting

dilutions are accepta$le in all cases.

Such simple treatment for environmental pollution on a wider scale

might have had greater merit in earlier centuries when physicalsurvival was often the highest imperative human population and

densities were lower technologies were simpler and their

$yproducts more $enign. 0ut these are often no longer the case.

=urthermore advances have ena$led measurement of

concentrations not possi$le $efore. #he use of statistical methods in

evaluating outcomes has given currency to the principle of pro$a$le

harm in cases where assessment is warranted $ut resorting to

deterministic models is impractical or infeasi$le. +n additionconsideration of the environment $eyond direct impact on human

$eings has gained prominence.

Met in the a$sence of a superseding principle this older approach

predominates practices throughout the world. +t is the $asis $y

which to gauge concentrations of effluent for legal release

eceeding which penalties are assessed or restrictions applied. ne

such superseding principle is contained in modern hazardous waste

laws in developed countries as the process of diluting hazardouswaste to ma%e it non,hazardous is usually a regulated treatment

process. ?igration from pollution dilution to elimination in many

cases can $e confronted $y challenging economical and

technological $arriers.

$reenhouse gases and glo%al warming

&ar$on dioide while vital for photosynthesis is sometimes referred

to as pollution $ecause raised levels of the gas in the atmosphereare affecting the *arthNs climate. 5isruption of the environment can

also highlight the connection $etween areas of pollution that would

normally $e classified separately such as those of water and air.

(ecent studies have investigated the potential for long,term rising

levels of atmospheric car$on dioide to cause slight $ut

critical increases in the acidity of ocean waters and the possi$le

effects of this on marine ecosystems.

Most polluted places in the developing world


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#he 0lac%smith +nstitute an international non,for,profit organization

dedicated to eliminating life,threatening pollution in the developing

world issues an annual list of some of the worldNs worst polluted

places. +n the 44/ issues the ten top nominees already

industrialized countries ecluded are located

in Azer$aijan &hina +ndia Peru (ussia%raine and Oam$ia.

Pollution and Its Control

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