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STERILIZATIONOF
WATER USING
BLEACHING POWDER
A C HE MI STR Y IN VE STI GA TOR YPR OGE CT
ANS HUL KUM AR
P ANDEYXIIB
[THIS PR OJ EC T LOO KS AT TH ETEC HN I Q U E C AL LE D
S T E R I LI Z A T ION OF W A T E R U S IN G
B L E A C H IN G POWDER W H IC H IS U S E D T O
PU R I FY W A T E R A N D M A K E S IT F I T FOR
D R IN K IN G .]
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IN D EX
1. Certificate of Authenticity
2. Acknowledgement
3. Introduction
-Need of Water
-Purification of Water
-Need for a stale !urification techni"ue
#. $heory
-%istory of Water !urification
-&leaching !owder and its !re!aration
-'se of &leaching !owder in (terili)ation of water
*. +,!eriment
-Aim
-Pre-e"uisite nowledge
-e"uirements
-Procedure
/. esult
0. &iliogra!hy
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C E R TI F I C A T E OF A U T H E N TI C IT Y
$his is to certify that An!"# K"$%& P%n'() a student of class
II has successfully com!leted the research !roect on the to!ic
4S*(&+#+,%*+-n - W%*(& /) "+n0 B#(%1!+n0 P-2'(&5 underthe guidance of 6rs. 6ohini &elani 7(uect $eacher8.
$his !roect is asolutely genuine and does not indulge in !lagiarism of akind.
$he references taken in making this !roect ha9e een declared
at the end of this re!ort.
(ignature 7 (uect $eacher8 (ignat+,aminer8
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A C K N O W L E D G E M E N T
I feel !roud to !resent my In9estigatory !roect in Chemistry on the
to!ic 4(terili)ation of Water using &leaching !owder5 which aims at
using &leaching !owder as a disinfectant and !urifier to make water
fit for drinking.
$his !roect wouldn:t ha9e een feasile without the !ro!er and
rigorous guidance of my Chemistry teacher 6rs. 6ohini &elani whoguided me throughout this !roect in e9ery !ossile way. An
in9estigatory !roect in9ol9es 9arious di;icult la e,!eriments which
ha9e to e carried out y the student to otain the oser9ations and
conclude the re!ort on a meaningful note. $hese e,!eriments are
9ery critical and in the case of failure may result in disastrous
conse"uences. $herey I would like to thank oth 6rs.&elani and
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I N T R O D U C TI O N
N(( ' - 2 % * ( &
Water is an im!ortant and essential ingredient in our "uest for
sur9i9al on this !lanet. It is 9ery essential for carrying out 9arious
metaolic !rocesses in our ody and also to carry out %emogloin
throughout the ody.
A daily average of 1 gallon per man is sufficient for drinking and cooking purposes. A
horse, bullock, or mule drinks about 11 gallons at a time. standing up, an average
allowance of 5 gallons should be given for a man, and 10 gallons for a horse or a
camel. An elephant drinks 25 gallons, each mule or ox drinks to ! gallons, each
sheep or pig to ! pints. "hese are minimum
#uantities.
$ne cubic foot of water % gallons &a gallon % 10
lbs.'.
(n order to fulfill such a huge demand of water, it needs to be purified and supplied in a
orderly and systematic way.
&ut with the increasing world !o!ulation the demand for drinking
water has also increased dramatically and therefore it is 9ery
essential to identify resources of water from which we can use water
for drinking !ur!oses. 6any a9ailale resources of water do not ha9e
it in drinkale form. +ither the water contains e,cess of Calcium or
6agnesium salts or any other organic im!urity or it sim!ly contains
foreign !articles which make it unfit and unsafe for =rinking.
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P " & + + 1 % * +- n - W % * ( &
$here are many methods for the !urification of water. (ome of them are
1. &oiling
2. >iltration
3. &leaching !owder treatment
#. (?=I( 7(olar Water
=isinfection8 And the list
goes on@.
&oiling is !erha!s the most commonly used water !urification
techni"ue in use today. While in normal households it is an e;icient
techni"ue it cannot e used for industrial and large scale !ur!oses. It
is ecause in normal households the water to e !urified is 9ery
small in "uantity and hence the water loss due to e9a!oration is
almost negligile. &ut in Industrial or large scale !urification of water
the water loss due to e9a!oration will e "uite high and the amount of
!urified water otained will e 9ery less.
>iltration is also used for remo9ing foreign !articles from water. ?ne maordrawack
of this !urification !rocess is that it cannot e used for remo9ing
foreign chemicals and im!urities that are miscile with water.
SODIS -& S-#%& W%*(& D++n(1*+-n + &(1-$$(n'(' /) *!(Un+*(' N%*+-n -& '++n(1*+-n - 2%*(& "+n0 -* '&+n3/-**#(4 "n#+0!*4 %n' % /#%13 "&%1(55 %* #(%* +n !-* n%*+-n2+*! &(0"#%) +n*(n( "n#+0!*.
Water-filled trans!arent ottles !laced in a hori)ontal !osition ato! aflat surface in strong sunlight for around fi9e hours will kill microesin the water. $he !rocess is made e9en more safe and e;ecti9e ifthe ottom half of the ottle or the surface itBs lying on is lackenedandor the flat surface is made of !lastic or metal. ItBs the
comination of heat and ultra9iolet light which kills the organisms.
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$he maor drawack of this !urification techni"ue is that it cannot e
used in countries with cold weather. Also the time consumed for
Purification !rocess is more and it also needs a Dlackened: surface
much like solar cookers.
N(( ' - & % * % / # ( 6" & + + 1 % * +- n * ( 1 ! n +7 " (
$herefore we need a !urification techni"ue which can e used
anytime and anywhere does not re"uire the use of any third !arty
content and which is also economically feasile on oth normal scale
and large scale.
%ence we look at the method of !urification of water using the
techni"ue of treatment y leaching !owder commonly known as
4Chlorination5.
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T H E OR Y
History of water purification in dierent parts of the world.
In 1E*# it was disco9ered that a cholera e!idemic s!read through
water. $he outreak seemed less se9ere in areas where sand filters
were installed. &ritish scientist Fohn (now found that the direct cause
of the outreak was water !um! contamination y sewage water. %e
a!!lied chlorine to !urify the water and this !a9ed the way for water
disinfection. (ince the water in the !um! had tasted and smellednormal the conclusion was finally drawn that good taste and smell
alone do not guarantee safe drinking water. $his disco9ery led to
go9ernments starting to install munici!al water filters 7sand filters
and chlorination8 and hence the first go9ernment regulation of
!ulic water.
In the 1EGHs America started uilding large sand filters to !rotect!ulic health. $hese turned out to e a success. Instead of slow sand
filtration ra!id sand filtration was now a!!lied. >ilter ca!acity was
im!ro9ed y cleaning it with !owerful et steam. (use"uently =r.
>uller found that ra!id sand filtration worked much etter when it was
!receded y coagulation and sedimentation techni"ues. 6eanwhile
such waterorne illnesses as cholera and ty!hoid ecame less and
less common as water chlorination won terrain throughout the world.
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&ut the 9ictory otained y the in9ention of chlorination did not last
long. After some time the negati9e e;ects of this element were
disco9ered. Chlorine 9a!ori)es much faster than water and it was
linked to the aggra9ation and cause of res!iratory disease. Water
e,!erts started looking for alternati9e water disinfectants. In 1GH2
calcium hy!o chlorite and ferric chloride were mi,ed in a drinking
water su!!ly in &elgium resultingin oth coagulation and disinfection.
$he treatment and distriution of water for safe use is one of thegreatest achie9ements of the twentieth century. &efore cities eganroutinely treating drinking water with chlorine 7starting with Chicagoand Fersey City in '( in 1GHE8 cholera ty!hoid fe9er dysentery andhe!atitis A killed thousands of '.(. residents annually. =rinking waterchlorination and filtration ha9e hel!ed to 9irtually eliminate thesediseases in the '.(. and other de9elo!ed countries. 6eeting the goalof clean safe drinking water re"uires a multi-arrier a!!roach thatincludes !rotecting source water from contamination a!!ro!riatelytreating raw water and ensuring safe distriution of treated water toconsumers: ta!s. =uring the treatment !rocess chlorine is added todrinking water as elemental chlorine 7chlorine gas8sodium hy!ochlorite solution or dry calcium hy!ochlorite. When a!!lied towater eachof these forms 4free chlorine5 which destroys !athogenic 7disease-causing8 organisms. Almost all systems that disinfect their water use
some ty!e of chlorine-ased !rocess either alone or in cominationwith other disinfectants. In addition tocontrolling disease-causing organisms chlorination o;ers anumer of enefits includingJ educes many disagreeale tastes and odorsJ +liminates slime acteria molds and algae that commonly grow in wsu!!lyreser9oirs on the walls of water mains and in storage tanksJ emo9es chemical com!ounds that ha9e un!leasant tastes and hinder
disinfectionandJ %el!s remo9e iron and manganese from raw water.As im!ortantly only chlorine-ased chemicals !ro9ide 4residual disinfectantle9els that!re9ent microial re-growth and hel! !rotect treated
water throughout the distriution system.
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>or more than a century the safety of drinking water su!!lies has
een greatly im!ro9ed y the addition of leaching !owder.
=isinfecting our drinking water ensures it is free of the
microorganisms that can cause serious and life-threatening diseases
such as cholera and ty!hoid fe9er. $o this day leaching !owder
remains the most commonly used drinking water disinfectant and the
disinfectant for which we ha9e the
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most scientific information. &leaching !owder is added as !art of
the drinking water treatment !rocess. %owe9er leaching !owder
also reacts with the organic matter naturally !resent in water
such as decaying lea9es. $his chemical reaction forms a
grou! of chemicals known as disinfection y-!roducts. Current
scientific data shows that the enefits of leaching our drinking water
7less disease8 are much greater than any health risks from $%6s andother y-!roducts. Although other disinfectants are a9ailale
leaching !owder remains the choice of water treatment e,!erts.
When used with modern water filtration methods chlorine is e;ecti9e
against 9irtually all microorganisms. &leaching !owder is easy to a!!ly
and small amounts of the chemical remain in the water as it tra9els in
the distriution system from the treatment !lant to the consumer:s
ta! this le9el of e;ecti9eness ensures that microorganisms cannot
recontaminate the water after it lea9es the treatment.
But what is bleaching powder and how is it prepared?
&leaching !owder or Calcium hy!ochlorite is a chemical
com!ound with formula Ca7Cl?8 2. It is widely used for water
treatment and as a leaching agent leaching !owder8. $hischemical is considered to e relati9ely stale and has greater
a9ailale chlorine than sodium hy!ochlorite 7li"uid leach8.
It is !re!ared y either calcium !rocess or
sodium !rocess. Calcium Process
2 Ca7?%82 K 2 Cl2 L Ca7Cl?82 K CaCl2 K 2 %2?
(odium Process
2 Ca7?%82 K 3 Cl2 K 2 Na?% L Ca7Cl?82 K CaCl2 K 2 %2? K 2 NaCl
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But how can this chemical be used to sterilize water?
$his chemical can e used for sterili)ing water y 'sing * dro!s ofleach !er each half gallon of water to e !urified and allowing it tosit undistured for half an hour to make it safe for drinking. iltration - for remo9al of carried o9er floc
0. =isinfection - for killing acteria
?ut of these !rocesses the role of &leaching !owder is only in the last ste! for=isinfection of water.
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E X P E R I ME N T
A +$8 T- D(*(&$+n( *!( '-%0( - /#(%1!+n0 6-2'(&&(7"+&(' -& *(&+#+,%*+-n -& '++n(1*+-n - '+(&(n*%$6#( - 2%*(&.
R ( 7" +& ( $ ( n *8 &urette titration flask 1HHml graduatedcylinder 2*Hml measuring flask weight o, gla)ed tile glasswool.
&leaching Powder Mlass wool H.1 N Na2(2?3 solution 1H I solutiondi;erent sam!les of water starch solution.
P & ( 5 R ( 7" + +*( K n - 2 #( ' 0 ( 8
1. A known mass of the gi9en sam!le of leaching !owder isdissol9ed in water to !re!are a solution of known concentration.
$his solution contains dissol9ed chlorine lierated y the action ofleaching !owder with water.
Ca?Cl2K%2HCa7?%82KCl2
2. $he amount of Chlorine !resent in the ao9e solution isdetermined y treating a known 9olume of the ao9e solution withe,cess of 1H !otassium iodide solution when e"ui9alent amountof Iodine is lierated. $he Iodine thus lierated is then estimatedy titrating it against a standard solution of (odium thiosul!hateusing starch solution as indicator.
Cl2K2I2.ClKI2
I2K2Na2(2?3Na2(#?/K2NaI
3. A known Oolume of one of the gi9en sam!les of water is treatedwith a known 9olume of leaching !owder solution. $he amount ofresidual chlorine is determined y adding e,cess !otassium iodide
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solution and then titrating against standard sodium thiosul!hatesolution.
#. >rom the readings in 2 and 3 the amount of chlorine and hence leachin!owder
re"uired for the disinfection of a gi9en 9olume of the gi9en sam!le of watcan ecalculated.
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P & -1( '" & ( 8
1. Pre!aration of leaching !owder solution. Weigh accurately 2.*g ofthe gi9en sam!le of leaching !owder and transfer it to a 2*Hmlconical flask. Add aout 1HH-1*Hml of distilled water. (to!!er theflask and shake it 9igorously. $he sus!ension thus otained isfiltered through glass wool and the filtrate is diluted with water 7in a
measuring flask8 to make the 9olume 2*Hml. $he solution otainedis 1 leaching !owder solution.
2. $ake 2Hml of leaching !owder solution in a sto!!ered conical flask and it to
2Hml of 1H I solution. (to!!er the flask and shake it 9igorously. $itratesolution against H.1N Na2(2?3 solution taken in the urette. Whenthe solution in the conical flask ecomes light yellow in color addaout 2ml starch solution. $he solution now ecomes lue in color.Continue titrating till the lue color ust disa!!ears. e!eat thetitration to get a set of three concordant readings.
3. $ake 1HHml of the water sam!le in a 2*Hml sto!!ered conical flask and ato
1Hml of leching !owder solution. $hen add 2Hml of I solution and sto!!the
flask. (hake 9igorously and titrate against H.1N Na2(2?3 solutionusing starch solution as indicator as descried in ste! 2.
#. e!eat the ste! 3 with other sam!les of water and record the oser9atio
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RE S ULT
Amount of the gi9en sam!le of leaching !owder re"uired todisinfect one litre of water
(am!le I
@@@g
(am!le II
@@@g
(am!le III
@@@g
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B IB L I O G RA P HY
1.$he 6edical front-QWater (u!!lyQ
h t t ! w ww . 9li . u s m e d ic a l s a n c a m! w
a t e r . h t m
2. 4Chemistry Proects5 www.icse.co m
3.%ow to li9e on OeryOery
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0.=rinking Water $reatmentContinuous Chlorination
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h t t ! w ww . ia n r ! u s . u n l. e d u e ! u lic ! a g e s !u l ic a t io n =. s !S!ulicationId3*E
E.Chlorination of =rinking Water
h t t ! w ww . w a t e r - r e s ea r c h . n e t w a t e r t r e a t m e n t c h lo r i n a t io n . h t m
G.Chlorination ?f =rinking Water 728
w ww . e d s t r o m .co m d oc li m i # 1 0# . !d f
1H.Wagenet
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1#.Q'nderstanding the New Consumer
Confidence e!ortQ
ww w . a w w a .o r g A d 9 oc a c y l u e t h u m G E co n s u
m e r .c f m
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1*.Q$esting for =rinking Water UualityQ NeMuide MEG-GH0 Coo!erati9
+,tension
Institute of Agriculture and Natural esources
'ni9ersity of Neraska-