project on treatment of dye by hydro-dynamic cavitation process

7/23/2019 Project on Treatment of Dye by Hydro-dynamic Cavitation Process

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Waste Water Treatment Of Dyes By Hydrodynamic Cavitation Process

Chapter 1

Introduction

1.1 Water a precious resource

Water covers about 71% of the Earths surface! and is vita" for a"" #no$nforms of "ife On Earth!

&7 % of the '"anets $ater is found in oceans! 17% in(round$ater! 17% in ("aciers and the ice

ca's of )ntarctica and *reen"and! a sma""fraction in other "ar(e $ater bodies On"y +,% of the

Earths $ater is fresh $ater! and&--% of that $ater is in ice and (round$ater .ess than /0% of

a"" fresh$ater is inrivers! "a#es! and the atmos'hereafe drin#in( $ater is essentia" to humans

and other "ivin( "ife Water is the#ey to "ife2 a crucia" resource for humanity and the rest of the

"ivin( $or"d Everyoneneeds it and not 3ust for drin#in( ociety uses $ater to (enerate and

sustainedeconomic (ro$th and 'ros'erity! throu(h activities such as farmin(! commercia"fishin(!

ener(y 'roduction! manufacturin(! trans'ort and tourism The mostcha""en(in( 'rob"em in

todays $or"d is mana(in( the su''"y and avai"abi"ity of safedrin#in( $ater for a"" human and

"ivin( creatures on this earth Water scarcity hasemer(ed as a 'rominent issue for communities

across the country 4ear"y everyre(ion of the country has e5'erienced $ater shorta(es in the "ast

five years Watersu''"ies have decreased due to the dryin( u' of streams! the dec"ine of

(round$ater"eve"s because of over 'um'in(! contamination of $ater resources! and an increase

in drou(ht conditions caused by c"imate chan(e The increase in human 'o'u"ation!6rbaniation

and ever8increasin( industria"iation causes de'"etion and contamination of our 'recious $ater

resources The society is "ess concerned about the conservationand 'rotection of our $ater body

from bein( 'o""uted Each year more than fivemi""ion 'eo'"e die from $ater8re"ated disease and

around one bi""ion 'eo'"e do nothave accesses to safe drin#in( $ater and sti"" $e are

deterioratin( this 'recious natura"resource On"y 1% of the tota" fresh $ater on the earth is

avai"ab"e for drin#in( 'ur'ose throu(h the different $ater bodies such as river! "a#es! 'ond etc

Des'ite thisfact that the $or"ds 'o'u"ation is (ro$in( by rou(h"y -/ mi""ion 'eo'"e each

yearand demand for fresh$ater is increasin( by 9: bi""ion cubic meters a year $e are 'o""utin(

this on"y avai"ab"e ;1%< form of $ater by contaminatin( this $ith $aste

Dept. Of CHEMICAL Page 1


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1.2 Water availability and use in India

=ndia accounts for +:,% of "and area and :% of $ater resources of the $or"d but re'resents 19%

of the $or"d 'o'u"ation Tota" uti"iab"e $ater resource in thecountry has been estimated to be

about 11+0 bi""ion cubic meter ;BC>< ;9&/ BC>from surface and :00 BC> from (round

$hich is 3ust +-% of the $ater derivedfrom 'reci'itation )bout -,% ;9-- BC>< of $ater usa(e

is bein( diverted forirri(ation! $hich may increase to 1/7+ BC> by +/,/ >a3or source for

irri(ation is(round$ater )nnua" (round$ater rechar(e is about :00 BC> of $hich +1+,

BC>is used for irri(ation and 1-1 BC> for domestic and industria" use ;C*WB! +/11

further reduce to 10:1 m0 in+/+, and11:/ m0 in +/,/ Hence! there is an ur(ent need for

efficient $ater resourcemana(ement throu(h enhanced $ater use efficiency and $aste $ater

recyc"in(

1.3 Water pollution

When to5ic substances enter "a#es! streams! rivers! oceans! and other $aterBodies! they (et

disso"ved or remain sus'ended in $ater or (et de'osited on the bed This resu"ts in the 'o""ution

of $ater $hereby the ?ua"ity of the $ater deteriorates!affectin( a?uatic ecosystems Po""utants

can a"so see' do$n and affect the(round$ater de'osits

Water 'o""ution has many sources The most 'o""utin( of them are the citye$a(e and industria"

$aste dischar(ed into the rivers The effects of $ater 'o""utionare not on"y devastatin( to 'eo'"e

but a"so to anima"s! fish! and birds Po""uted $ateris unsuitab"e for drin#in(! recreation!

a(ricu"ture! and industry =t diminishes theaesthetic ?ua"ity of "a#es and rivers >ore serious"y!

contaminated $ater destroys a?uatic "ife and reduces its re'roductive abi"ity Eventua""y! it is a

haard to humanhea"th 4obody can esca'e the effects of $ater 'o""ution

1.4 Wastewater Treatment Technologies

Waste$ater Treatment P"ant is a faci"ity desi(ned to receive the $aste fromdomestic!

commercia"! and industria" sources and to remove materia"s that dama(e$ater ?ua"ity and

com'romise 'ub"ic hea"th and safety $hen dischar(ed into $aterreceivin( systems The 'rinci'a"



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ob3ective of $aste$ater treatment is (enera""y toa""o$ domestic and industria" eff"uents to be

dis'osed off $ithout dan(er to humanhea"th or unacce'tab"e dama(e to the natura"

environment>ethods of treatment in $hich the a''"ication of 'hysica" forces 'redominateare

#no$n as unit o'erations. >ethod of treatment in $hich the remova" ofcontaminants is brou(ht

about by chemica" or bio"o(ica" reactions are #no$n as a unit'rocesses. )t the 'resent time! unit

o'erations and 'rocesses are (rou'ed to(ether to'rovide various "eve"s of treatment #no$n as

're"iminary! 'rimary! advanced 'rimary!secondary ;$ithout or $ith nutrient remova"< and

advanced ;or tertiary< treatment ;seeTab"e 1+etca"f A Eddy!:thed


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1.5 Cavitation

Cavitation is defined as the 'henomena of the formation! (ro$th andubse?uent co""a'se of

micro bubb"es or cavities occurrin( in e5treme"y sma"" interva" of time ;mi""iseconds< and at

mu"ti'"e "actations in the reactor! re"easin( "ar(e >a(nitudes of ener(y The effects of cavity

co""a'se are! creation of hot s'ots!re"easin( hi(h"y reactive free radica"s! c"eanin( of so"id

surfaces! and enhancement = mass transfer rates The co""a'se of bubb"es (enerates "oca"ied

hot s'ots $ithtransient tem'erature of about 1/!/// ! 'ressures of about +/// atm ;Diden#o

et a"1&&&


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*o(ate! +/1+any researchers have re'orted that u"trasonic irradiation 'rocess $as ca'ab"e

of de(radin( Farious reca"citrant or(anic com'ounds such as 'heno" com'ounds! ch"oroaromatic

Com'ounds! a?ueous carbon tetrach"oride! 'esticides! herbicides! benene com'ounds!

'o"ycyc"ic aromatic hydrocarbons and or(anic dyes The fre?uency of u"trasound! irradiatin(

surface! intensity of sound $ave! ca"orimetric efficiency of u"trasonic E?ui'ment ;'o$er

dissi'ated into the system 'er unit 'o$er su''"ied

medium and the 'resence of air and so"id Partic"es are the im'ortant 'arameters $hich affects the

cavitationa" efficiency o )coustic cavitationa" reactor

1.5.2 !ydrodynamic cavitation

One of the a"ternative techni?ues for the (eneration of cavitation is the use of hydrau"ic devices

$here cavitation is (enerated by the 'assa(e of the "i?uid throu(h Constriction such as va"ve!

orifice '"ate! venturi etc ;*o(ate and Pandit! +///I enthi"umar and Pandit! 1&&&I >oho"#ar et

a"! 1&&&I *o(ate and Pandit! +//,I >oho"#ar and Pandit! +//1


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Chapter 2

"iterature #urvey

2.1 Introduction

Waste$ater treatment ;WWTP< has deve"o'ed a "ot over the "ast fe$ decades

@rom a sma"" system! it has become a hu(e industry no$ The most common method to treat the

$aste$ater is the activated s"ud(e 'rocess! $here treatment is done by uti"iin( different

microor(anisms under different o'eratin( conditions )"thou(h a si(nificant im'rovement has

been achieved in $aste$ater treatment! sti"" the (eneration of s"ud(e or bioso"ids has remained

'rob"ematic Primary and secondary c"arification is the t$o unit o'erations $hich (enerate

s"ud(e in a $aste$ater treatment '"ant "ud(e recovered from the 'rimary c"arifier is ty'ica""y

readi"y de(radab"e com'ared to the secondary s"ud(e (enerated from biomass $hich is more

resistant to de(radation ) si(nificant 'ortion of money is s'ent to treat and dis'ose of this

s"ud(e =n WWTPs

To reduce the amount of s"ud(e as $e"" as to im'rove the s"ud(e ?ua"ity! different disinte(ration

techno"o(ies have been a''"ied in the s"ud(e treatment 'rocess Disinte(ration techno"o(ies he"'

to fra(ment the ce"" $a"" and re"ease the intrace""u"ar com'ounds by the a''"ication of different

'hysica" or chemica" methods Disinte(rated s"ud(e can be used in both aerobic and anaerobic

bio"o(ica" 'rocesses as a substrate Disinte(rated s"ud(e can be further treated in one of the

fo""o$in( $ays

)naerobic di(estion can be im'roved as $e"" as acce"erated by first a''"yin( disinte(ration to

$aste s"ud(e Disinte(ration he"'s to acce"erate the hydro"ysis 'rocess by disru'tin( the ce""

$a""s and re"easin( the or(anic matter inside the ce""! $hich is the "imitin( ste' in the di(estion

'rocess Disinte(rated s"ud(e im'roves biomass 'roduction in an anaerobic di(estion 'rocess

and it im'roves 'hos'horus recovery and the nutrient remova" 'rocesses by transferrin( the

activated s"ud(e so"ids into the "i?uid 'hase=n a $aste$ater nitro(en remova" treatment 'rocess!

disinte(rated s"ud(e can be used as a source of carbon for (entrification

Disinte(rated s"ud(e can be a''"ied to reduce s"ud(e bu"#in( and foamin( in an activated s"ud(e

Treatment 'rocess by brea#in( u' the fi"amentous structure and "ar(er f"oc#s ome of the

common disinte(ration 'rocesses are (iven in Tab"e 1 )"" the methods have been deve"o'ed $ith

a common (oa" to achieve 'artia" or com'"ete "ysis of the ce""! $hich means the destruction and



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re"ease of the or(anic matter inside in the bacteria" ce"" E5trace""u"ar 'o"ymeric substances may

a"so be de(raded by these disinte(ration techni?ues

Tab"e 1 Different methods of disinte(ration ;,ore $or# needs to be done to find out the behavior of this instrument under

hi(h fre?uency and hi(h dissi'ation conditions Hi(her fre?uencies of o'eration are suitab"e for

the destruction of 'o""utants u' to an o'timum va"ue $hich de'ends on the characteristics of the

'o""utant Fery fe$ investi(ations have been made on the destruction of 'o""utants usin( hi(her

fre?uencies as its difficu"t to o'erate at fre?uencies (reater than +// #H unnin( a sono

chemica" reactor at hi(her fre?uencies in continuous o'eration at a "ar(er sca"e is difficu"t as it

causes erosion of the transducer surface Po$er re?uirement increases $ith fre?uency and this

can ma#e the 'rocess uneconomica" due to the fact that a "ar(e amount of su''"ied ener(y $i"" be

used on"y for the (eneration of the cavities >u"ti'"e fre?uencies 'roduce more intense cavitation

than sin("e fre?uency o'eration and resu"ts in hi(her yie"d of transformation but $ith minima"

'rob"ems of o'eration With an increase in cavitationa" activity! "ar(er vo"umes of eff"uent can be

treated effective"y 6"trasonic 'robes $ith hi(her irradiatin( surface areas are more ener(y

efficient as they ensure the uniform dissi'ation of ener(y;-achnic#a et a" combined hydrodynamic cavitation $ith anaerobic

di(estion and sho$ed that bio(as 'roduction increased u' to 101% $ith the addition of 0/% of



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vo"ume disinte(rated s"ud(e in the fermentation 'rocess They used a 1+ mm no"e for the

(eneration of cavitation =t $as a"so re'orted that so"ub"e COD increased by +-: m(G. after

a''"ication of cavitation for &/ minutes! sho$in( evidence that the or(anic matter and 'o"ymer

in the activated s"ud(e $as transferred from the so"id 'hase to the "i?uid 'hase Hydrodynamic

cavitation $as sho$n to im'rove 'hos'horus remova" and recovery in the form of struvite by

so"ubi"iin( 'hos'horus and ammonium nitro(en! as $e"" as 'otassium! ma(nesium and ca"cium

cations from the so"id 'hase to the "i?uid imi"ar resu"ts $ere obtained $hen this techno"o(y

$as a''"ied to the foam co""ected from a fu"" sca"e enhanced bio"o(ica" nutrient treatment

remova" '"ant Huan( et a" demonstrated that de$ater abi"ity of s"ud(e can be im'roved by

a''"yin( hydrodynamic cavitation;1-artin and *a"ey used static

mi5ers in their study and observed an increasin( mass transfer coefficient $ith decreasin( $ater

f"o$ rate and increasin( (as f"o$ rate =t has a"so been that oone transfer efficiency in static

mi5ers increases $ith an increase in the 'ressure dro' or a decrease in (asG"i?uid ratio and that

transfer is inde'endent of oone "oadin( )s static mi5ers are not used fre?uent"y $ith

$aste$ater! more studies are re?uired to ca"cu"ate the ener(y re?uirement! as the 'ressure dro'

$ou"d be hi(her due to the sus'ended so"ids and other eff"uent 'ro'erties com'ared to $ater

containin( microor(anisms

Tab"e : o"ubi"ity of oone and o5y(en in $ater

2.4.2 -one in water treatment

Oone is used for the treatment of $aste$ater as $e"" as for the disinfection of $ater )s a

'o$erfu" o5idant! oone is used to o5idie a variety of contaminants 'resent in $ater and

$aste$ater ome of the a''"ications of oone in $ater treatment are "isted in Tab"e , Oone is

a"so used to increase the biode(radabi"ity of or(anic com'ounds =n $aste$ater treatment '"ants

oone can be used as a 're8treatment before the bio8di(estion and a"so can be used in the recyc"e

"oo' to reduce the overa"" s"ud(e 'roduction in the '"ant;++ost of the studies $ere focused on thede(radation of different 'o""utants

usin( sin("e or mu"ti'"e ho"e orifice '"ates andsyner(etic effect of hydrodynamic cavitation and

other additives 4o studies havebeen found on the com'arison of venturies of different sha'es

and orifice '"ate andthe subse?uent effect of the cavitatin( device on the de(radation #inetics

)sdiscussed ear"ier the (eometry of a cavitatin( device has a stron( inf"uence on theentire

cavitation ;ince'tion! (ro$th and co""a'se< behaviours The C@D ana"ysis byBashir et a" ;+/11oyno 00+! \ h'! +/- F)C

contro""ed The sam'"es $ere co""ected from the tan# and du'"icate measurements $ere made for

a"" the sam'"es;+:ethods ,01/ B ;)PH) et a"! +//,< by usin( a =.

,,/ TOC8T4 ana"yer ;C)

=n case of the sam'"es ta#en after &/ minutes! 0 m. and , m. of fi"tered sam'"e $ere used to

measure the BOD,

4.4.4 /iodegradable C*

) sim'"e batch reactor $as used to determine the readi"y biode(radab"e COD as i""ustrated in

@i(ure & )n Er"enmeyer f"as# of 1 . vo"ume $as used as a reactor )ir $as su''"ied

continuous"y by usin( a sma"" tube at the bottom of the f"as# and a ma(netic stir '"ate and stir bar

$ere used to #ee' the contents of the reactor in sus'ension The $ater "oss due to eva'oration

$as accounted for and re'"aced by disti""ed $ater The e5'eriment $as o'erated at room

tem'erature The sides of the reactor and aeration tubin( $ere c"eaned re(u"ar"y by usin( a bott"e

brush to ensure the sus'ension of biomass in the reactor am'"es co""ected initia""y and after &/



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minutes of a''"ication of oone8hydrodynamic cavitation $ere assessed for so"ub"e

biode(radab"e COD =n both cases! +// m. of fi"tered sam'"e $ere ta#en from the reactor and

then + m. of activated s"ud(e from the 'i"ot '"ant $as added Phos'hate buffer $as added to

both reactors to maintain the 'H around 7/ =nitia" so"ub"e COD $as measured am'"es $ere

ta#en from the reactor and so"ub"e COD $as measured unti" the so"ub"e COD stabi"ied in the

reactor ;1,8+/

a"so have a critica" inf"uence on a?uatic biota! and every #ind of or(anism has a ty'ica" sa"inity

ran(e that it can to"erate >oreover! the ionic com'osition of the $ater can be critica" @or

e5am'"e! c"adocerans ;$ater f"eas< are far more sensitive to 'otassium ch"oride than sodium

ch"oride at the same concentration Conductivity $i"" vary $ith $ater source2 (round $ater!

$ater drained from a(ricu"tura" fie"ds! munici'a" $aste $ater! rainfa"" Therefore! conductivity

can indicate (round$ater see'a(e or a se$a(e "ea# Conductivity is measured by a 'robe! $hich

a''"ies vo"ta(e bet$een t$o e"ectrodes The dro' in vo"ta(e is used to measure the resistance of

the $ater! $hich is then converted to conductivity Conductivity is reci'roca" to resistance and is

measured in the amount of conductance over a certain distance The conductivity unit has been

ca""ed ^mho_ because it is the inverse of ^ohm_! the resistance unitThe basic unit is mhoGcm!



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other$ise #no$n as 1 iemenWe have ta#en the resu"ts for above terms and discussed the

re"ation of resu"ts to our 'ro3ect to'ic These discussion is made in fo""o$in( cha'ter

Chapter 5

esults and *iscussion

5.1 Introduction

=n this cha'ter e5'erimenta" resu"ts are 'resented! com'ared and discussed for 're8treatment ie!

cavitation )''"icabi"ity of the disinte(rated s"ud(e is a"so discussed

+ercentage o% %ree area %or the %low

To ?uantify the effect of free area on the cavitation intensity a 'arameter ca""ed

is introduced $hich is the ratio of the tota" 'erimeter of the ho"e to the tota" area of the o'enin(

Q Tota" 'erimeter of the ho"es G Tota" area of o'enin(

Q n R +S ;dhG+< G ;dhG+


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simi"ar trend for iodine "iberation! e5ce't $ith a different order of ma(nitude This $as due to

the fact that a hi(her va"ue of co""a'se 'ressure is re?uired forrhodamine B de(radation

com'ared to the decom'osition of = =t $as a"so observed that a '"ate $ith a "ar(er number of

ho"es 'roduced a hi(her rate of de(radation $ith the same va"ue!$hich $as a"so confirmed by

umar in a bubb"e dynamics mode" On the other hand cavity co""a'se 'ressure decreased $ith

an increase of free f"o$ area Thus for a certain f"o$ area! an orifice '"ate $ith a "ar(er number

of ho"es $ith a sma"" diameter $i"" (ive a better cavitation effect! as a "ar(er number of cavities

e5'eriences hi(her turbu"ence due to the increase of shear "ayer;19oreover the cavitation number ;CF< $as

ca"cu"ated from the e?uation +1 Cavitation (enera""y occurs at CvN1 The cavitation numbers

ca"cu"ated for the in"et 'ressures of 0, 'si $as /,:indicatin( the stron( "i#e"ihood that cavitation

$as occurrin( @or both ca"cu"ations! atmos'heric 'ressure $as ta#en as recovered 'ressure

5.3 Chemical Aygen *emand (C*)&

o"ubi"isation of s"ud(e $as assessed in terms of the (eneration of so"ub"e COD ;COD


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indicated that the tota" COD of the s"ud(e $as a''ro5imate"y 17// m(G. $hich means that after

about + hours of treatment! ,/% of the s"ud(e $as so"ubi"ised

TIMEplate1mm

plate2mm

plate 1mm 5!le

plate 2mm5 !le

0 1500 1500 1500 150030 1445 1458 1456 146660 1220 1330 1340 1345

90 1032 1038 1046 1058

120 867 873 888 909

Tab"e 72 COD F Time

0 20 40 60 80 100 120 140

850

950

1050

1150

1250

1350

1450

1550

plate 1mm plate 2mm plate 1mm 5 !le plate 2mm 5 !le "#E$%

"#E$% "#E$% "#E$%

time

COD

@i(ure -2 Concentration of COD $ith in"et 'ressures in hydrodynamic cavitation treatment

Based on the concentration of COD obtained in the e5'eriments it can be conc"uded that (reater

so"ubi"isation of s"ud(e $as obtained in the combined a''"ication of oone and cavitation at

hi(her in"et 'ressure and a"so the rate of so"ubi"isation decreases $ith time

5.4 #oluble total organic carbon (TC)

The amount of or(anic matter re"eased by s"ud(e so"ubi"isation $as estimated by measurin(

so"ub"e TOC @i(ure 1& i""ustrates the amount of TOC re"eased for the combined! as $e"" as

individua" a''"ication of oone and cavitation in the short term e5'eriments On"y cavitation did

not 'roduce any si(nificant re"ease of so"ub"e TOC com'ared to the other treatments @i(ure +/



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i""ustrates the effect of in"et 'ressure on or(anic matter re"ease =t $as observed that after /

minutes of treatment! the TOC concentration $as about -&1- ''m usim( an in"et 'ressure of 0,

'a!for a"" '"ates! $hereas at after 1+/ min TOC concentration for /&, mm orifice '"ate $as

01:9''m $hich $as minimum as com'ared to other '"ates

)mon( a"" the '"ates a''"ied! the /&,mm orifice '"ate demonstrated the hi(hest re"ease of

or(anic carbon at the hi(her in"et 'ressure due to a hi(her rate of so"ubi"isation of the s"ud(e The

concentration of TOC continued to increase $ith time! indicatin( the re"ease of or(anic matter

due to the ce"" disru'tion

Tab"e -2 TOC vs time

0 5 10 15 20 25 30 35 40 450

10

20

30

40

50

60

70

80

90

100

plate 1mm plate 2mm plate 1mm &5 !le' plate 2mm &5 !le'

t(me

TOC

@i(ure &2 e"ease of so"ub"e tota" or(anic carbon usin( different disinte(ration conditions


TIMEplate1mm

plate2mm

plate 1mm &5!le' plate 2mm &5 !le'

0 92.18 92.18 92.18 92.18

10 60.65 62.25 63.26 69.645

20 46.533 58.63 50.56 62.36

30 41.235 51.36 42.35 49.54

40 34.26 45.36 36.64 46.26


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5.5Total dissolved solids (T*#)&

The amount of disso"ved so"ids re"eased by s"ud(e so"ubi"isation $as estimated by measurin(

TD @i(ure 1& i""ustrates the amount of TD re"eased for the hydrodynamic cavitation in the

short term e5'eriments On"y cavitation did not 'roduce any si(nificant re"ease of so"ub"e TD

com'ared to the other treatments =t $as observed that after / minutes of treatment! the TD

concentration $as about 10&1- ''m usin( an in"et 'ressure of 0, 'si!for a"" '"ates! $hereas at

after 1+/ min TD concentration for /&, mm orifice '"ate $as &1:9''m $hich $as minimum

as com'ared to other '"ates

)mon( a"" the '"ates a''"ied! the /&,mm orifice '"ate demonstrated the hi(hest re"ease of

disso"ved so"ids at the hi(her in"et 'ressure due to a hi(her rate of so"ubi"isation of the s"ud(e

The concentration of TD continued to increase $ith time! indicatin( the re"ease of or(anic

matter due to the ce"" disru'tion

Tab"e &

TD F

T=>E


TIME plate 1mmplate2mm

plate 1mm &5!le')

plate 2mm &5!le'

0 138.43 138.43 138.43 138.43

10 96.43 97.15 98.23 98.6620 97.65 99.6 100.25 98.32

30 95.45 97.64 98.235 97.24

40 94.52 96.32 98.21 97.56


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0 10 20 30 40 50

plate 1mm plate 2mm plate 1mm &5 !le') plate 2mm &5 !le'

TIME

TDS

@i(ure 1/2 e"ease of tota" disso"ve so"ids usin( different disinte(ration conditions

5.B Conductivity&

Conductivity is measured by a 'robe! $hich a''"ies vo"ta(e bet$een t$o e"ectrodes The dro' in

vo"ta(e is used to measure the resistance of the $ater! $hich is then converted to conductivity

Conductivity is reci'roca" to resistance and is measured in the amount of conductance over a

certain distance =t $as observed that after / minutes of treatment! the conductivity $as about

++, sGsusim( an in"et 'ressure of 0, 'si! for a"" '"ates! $hereas at after 1+/ min conductivity

for /&, mm orifice '"ate $as 19,-, sGs $hich $as minimum as com'ared to other '"ates

)mon( a"" the '"ates a''"ied! the /&,mm orifice '"ate demonstrated the hi(hest re"ease ofdisso"ved so"ids at the hi(her in"et 'ressure due to a hi(her rate of so"ubi"isation of the s"ud(e

The concentration of conductivity continued to decrease $ith time! indicatin( the re"ease of

or(anic matter due to the ce"" disru'tion

5. Temperature and p!

The chan(es in tem'erature are i""ustrated in @i(ures 09 for different disinte(ration conditions

@rom @i(ure 09! a simi"ar tem'erature ;9,C in &/ minutes< increase $as observed for both the

combined a''"ication of oone and cavitation! and cavitation a"one This mi(ht be due to the

co""a'se of cavities $hich causes the increase of tem'erature ;Benito et a"! +//,


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TIMEplate1mm

plate2mm

plate 1mm &5!le'

plate 2mm &5!le'

0 31.5 31.5 31.5 31.5

20 41.3 40.4 39.2 39.6

40 49 47.23 47.54 48

60 53.5 50.4 53.65 54.32

Tab"e 11 tem'erature vs time

0 10 20 30 40 50 60 70

20

30

40

50

60

70

80

plate 1mm plate 2mm plate 1mm &5 !le' plate 2mm &5 !le'

t(me

Temp*at+*e

@i(ure 112 Chan(es in tem'erature for different diameters of orifice '"ate

5.D *iscussion

)"" the e5'eriments indicate that combined a''"ication of hydrodynamic cavitation and oone

resu"ted in better s"ud(e disinte(ration than did the individua" treatments This may be due to the

fo""o$in( reasons

Cavitation causes the dese(re(ation of f"ocs of microor(anisms >icroor(anisms 'resentin the

form of f"ocs may 'rotect the inner microor(anisms from contact $ith oone The cavitation

brea#s these f"ocs and e5'oses the inner microor(anisms to oone

Cavitation increases the 'enetration of oone mo"ecu"es to the microor(anisms by acce"eratin(

mass transfer

Cavitation can a"so increase the 'ermeabi"ity of the substances by brea#in( the chemica"

bonds bet$een the mo"ecu"ar substances



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The oone decom'osition and the activity of free radica"s may be increased due to the

cavitation 'rocess =n activated s"ud(e! bacteria" ce""s form macrof"ocs $ith sies ran(in( from

1// to 1,/ ]m as 'resented in @i(ure :+ These macrof"ocs are com'osed of microf"ocs! of sie

ran(in( from 1/81, ]m! $hich are main"y active ce""s entra''ed in a matri5 of e5o'o"ymer

Cavitation he"'s to brea# these f"ocs and to e5'ose the inner 'artic"es to oone! and this may

increase the oone activity a(ainst the s"ud(e Cavitation has been sho$n to increase the aeration

;.a< efficiency $hich resu"ts in intensified inter'hase mass transfer imi"ar"y! $ith oonation

more effective uti"iation of oone (as $ou"d be obtained ;Dah" et a"! 1&79


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5.E pplication o% disintegrated sludge

) ty'ica" set8u' of the activated s"ud(e bio"o(ica" nutrient remova" 'rocess is 'resented in @i(ure

+: The 'rocess is com'osed of anaerobic! ano5icGdenitrification! aerobic reactors to treat the

$aste$ater by usin( biomass @i(ure :0 i""ustrates the 'otentia" '"aces for the a''"ication of

s"ud(e disinte(ration $ith re(ards to the $aste$ater treatment and s"ud(e mana(ement

Disinte(rated s"ud(e can be returned to both interna" ;D< and e5terna" ;E< recircu"ation "ines in

the 'rocess to(ether $ith s"ud(e from the secondary sett"in( tan# to any of the anaerobic ;)

ano5ic ;B< aerobic ;C< reactors

@i(ure 102 Potentia" '"aces for addin( s"ud(e disinte(ration techno"o(y

=n the anaerobic one F@)s (enerated by fermentative bacteria! are ta#en u' by 'hos'horus

accumu"atin( bacteria ;P)O

nitrate remova" throu(h denitrification if there is a shorta(e of or(anic matter in the $aste$ater

f"o$in( into the recator =n the aerobic one it $i"" a"so he"' the 'hos'horus8accumu"atin(



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bacteria to re'roduce and easier co""ection of 'hos'horus and $i"" (uarantee their surviva"

sho$ed that the addition of disinte(rated s"ud(e to the ano5ic reactor cou"d 'rovide an effective

carbon source and it im'roved the nitro(en remova" efficiency by 1/% $ithout reducin( the

eff"uent ?ua"ity

=n the aerobic one! non8sett"in(! so"ub"e and co""oida" carbon com'ounds in $aste$ater are

metabo"ied by heterotro'hic microor(anisms The introduction of disinte(rated s"ud(e $i""

'rovide additiona" or(anic substrate that may contribute to faster bacteria" (ro$th $hich $i""

favor the deve"o'ment of feedin( fauna =t has been re'orted that the addition of disinte(rated

s"ud(e in the activated s"ud(e chamber did not "ead to the rea''earance of fi"amentous bacteria

Disinte(rated s"ud(e can a"so be cou'"ed to nutrient recovery! asstruvite due to the re"ease of

'hos'hate and ammonia The introduction of disinte(rated s"ud(e direct"y ;*< or $ith thic#ened

activated s"ud(e ;@< to a fermenter $i"" im'rove the fermentation 'rocess The direct addition of

disinte(rated s"ud(e into the di(estion chamber $i"" he"' to increase the enymatic activity of the

fermentation 'rocess! $hich $i"" increase the bio(as 'roduction The disinte(ration 'rocess he"'s

to re"ease the intra and e5trace""u"ar enymes by ce"" "ysis and su''"ies the or(anic substrate to

bacteria" 'o'u"ation in more di(estib"e form



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Chapter B

Conclusions and ecommendations

=t has been conc"uded that hydrodynamic cavitation can be effective"y uti"iedfor the de(radation

of bio refractory 'o""utants This study sho$s that hydrodynamiccavitation has a 'otentia" of

a''"ication on an industria" sca"e! $hi"e its successfu" im'"ementation on an industria" sca"e

de'ends on severa" 'arameters such as (eometrica"! o'eratin( ;o'eratin( 'ressure and cavitation

number< and 'hysicochemica" 'ro'erties ;density! viscosity and 'H of the so"ution< of

$aste$ater to be treated The fo""o$in( conc"usion can be dra$n from this study

=t has been found that hydrodynamic cavitation is ca'ab"e of o5idiin( or(anic'o""utants and

further the efficiency can be enhanced by re(u"atin( o'eratin('arameters ;o'eratin( 'ressure and

cavitation number< and 'hysico8chemica"'ro'erties of the f"uid to be treated The studied carried

out in cha'ter + and 0indicates that in"et 'ressure and cavitation number are the t$o im'ortant

'arameters $hich affects the de(radation rate of dyes =t $as conc"uded that a moderate in"et'ressure ;, bar< is sufficient for o5idiin( or(anic com'ounds and the hydrodynamic cavitation

shou"d a"$ays be o'erated above the cho#ed cavitation condition;Cv Q /10< to (et the ma5imum

cavitationa" yie"d for the cavitatin( device studied in these $or#

=t has a"so been found that the efficiency of hydrodynamic cavitation isstron("y de'endent on the

o'eratin( 'H! state of mo"ecu"e ;$hether mo"ecu"ar or ionic< and nature ;hydro'hobic and

hydro'hi"ic< of the 'o""utant mo"ecu"e The syner(istic coefficient (reater than one indicates that

the combination ofhydrodynamic cavitation and H+O+ ;o5idiin( a(ent< (ives hi(her ener(y

efficiency and therefore combination is recommended instead of individua" 'rocesses to (et the

enhanced de(radation rate The com'arison of hydrodynamic cavitation and acoustic cavitation

sho$ed that hydrodynamic cavitation is more ener(y efficient than the acoustic cavitation and

a"most 10 times hi(her cavitationa" yie"d $as obtained in the case of hydrodynamic cavitation as

com'ared to acoustic cavitation The hi(her ener(y efficiency of hydrodynamic cavitation ma#es



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it a cost effective techno"o(y $hich has 'otentia" of sca"e u' on an industria" sca"eThe studied

carried out in cha'ter : indicates that the cavitation yie"d in the case of hydrodynamic cavitation

de'ends on the (eometrica" 'arameters of hydrodynamica""y cavitatin( device

The throat sie ;area and 'erimeter of throat

because considerin( on"y one 'arameter in the desi(n of a cavitatin( device $ou"d not resu"t in

the 'ossib"e o'timiation of a"" cavitationa" condition for the desired effects The treatment of

industria" eff"uent havin( bio refractory 'o""utants usin( hydrodynamic cavitation sho$ed that

hydrodynamic cavitation is ca'ab"e of reducin( 'o""utant concentration of such eff"uent u' to a

reusab"e "eve"

@urther the 'otentia" of hydrodynamic cavitation for an industria" a''"icationis e5'"ored throu(h

the successfu" treatment of disti""ery $aste$ater =t $as conc"uded that the hydrodynamic

cavitation is ca'ab"e of enhancin( the efficiency of conventiona" bio"o(ica" 'rocesses in terms of

reduction of to5icity as $e"" as increase in bio(as (eneration! a"on( $ith a si(nificant"y net

hi(her reduction in COD and co"or for the treatment of com'"e5 disti""ery $aste$ater Hence! it

can be conc"uded that the hydrodynamic cavitation can be effective"y uti"ied for the treatment of

com'"e5 bio refractory 'o""utants and can serve as a cost effective advance treatment

techni?ue$hich can be used as an individua" or in combination $ith other conventiona"treatment

'rocesses! such that the efficiency of conventiona" bio"o(ica" treatment

'rocesses in hand"in( the com'"e5 $aste$ater can be im'roved

B.1 Conclusions

The fo""o$in( conc"usions $ere made based on the resu"ts obtained from the 'resent study of

hydrodynamic cavitation for 'aint industry $aste $ater s"ud(e disinte(ration

@rom this 'ro3ect $e conc"ude that the $hen the diameter of orifice '"ate is as sma"" as

then better resu"t can be obtained

Hydrodynamic cavitation has hi(her ca'acity for s"ud(e disinte(ration than any oher

$aste$ater treatment techno"o(ies a''"ied a"one



45/48


Within the o'eratin( conditions a''"ied! cavitation itse"f is not sufficient for the

disinte(ration of s"ud(e

) ma5imum of ,/% of the s"ud(e $as so"ubi"ised after + hours treatment=t $as a"so

observed that most of the s"ud(e $as so"ubi"ised $ithin the first + hours of treatment

B.2 ecommendations

=n our 'resent study $e have used an in"et 'ressure of 0, 'si at a f"o$ of , .'m for cavitation

$hich $as "o$ com'ared to the f"o$ and 'ressure a''"ied in other studies esearch shou"d be

conducted at hi(her in"et 'ressure to find out the fu"" 'otentia" of cavitation on s"ud(e

disinte(ration

=n our 'resent research $e used a different sies of orifice '"ates to (enerate the cavities Other

researchers have sho$n that mu"ti'"e ho"e orifices (ive better cavitationa" yie"d to de(rade =

and rhodamine B )"thou(h cavitation can be induced $ith sin("e or mu"ti'"e ho"e orifices! there

may be advanta(es in usin( a venturi for this 'ur'ose @urther research mi(ht be usefu" to assess

the effect of cavitation on s"ud(e disinte(ration by usin( different sets of orifices or a venturi

=n our 'resent research $e measured on"y the a''"ied oone concentration 4o measurements

$ere made of off8(as oone concentration To find out the actua" oone transfer efficiency it is

necessary to find out the amount of oone consumed by the s"ud(e in a certain 'eriod of time o

in the ne5t ste' of the research! off8(as oone concentration shou"d be considered to ?uantify the

increase in the oone transfer efficiency due to cavitation

=t $as assumed in severa" 'revious studies that cavitation re"eases hi(h"y reactive free radica"s!

but none of the studies actua""y ?uantified the radica" effects se'arate"y @urther research is

re?uired to find out the radica" effects of cavitation

@ina""y! a''"ication of hydrodynamic cavitation shou"d be a''"ied in a 'i"ot sca"e $aste$ater

treatment 'rocess and research is necessary to find out the behaviour of the 'rocess due to this

a''"ication



46/48


C!+TF

eferences

1 )de$uyi! * ;+//1

;+//+

6"trasonics onochemistry! 1,;0

Enhanced anaerobic de(radation of mechanica""y disinte(rated s"ud(e Water cience and

Techno"o(y! 09;11

1/+1

11 Benito! ! )rro3o! ! Hau#e! *! Fida"! P! de Conceicao Cunha! > and Brebbia! C

;+//,


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1+ Hydrodynamic cavitation as a "o$8cost )OP for $aste$ater treatment2 Pre"iminary

resu"ts and a ne$ desi(n a''roach Water esources >ana(ement ===! ! :&,8,/:10 Berna"8>artine! )! Carrere! H! Patureau! D and De"(enes! V ;+//,

Techno"o(y!+-;-

1, Boeh"er! >! ie(rist! H! O"es#ie$ic! V! van .oosdrecht! >! E#ama! *! "a Vansen! V!

et a" ;+//9ana(ement in

Waste$ater Treatment Processes and ecyc"e treams e"ected Pa'ers from the =W)

=nternationa"Conference! He"d in ra#o$! Po"and! 1&8+1 e'tember +//, ! ,0 ;1+< ''

+/78+19 Bou(rier! C! )"basi! C! De"(enes! V and Carrere! H ;+//9

and economic as'ects The Canadian Vourna" of Chemica" En(ineerin(! ,1;0! Wu! L and Ondrusch#a! B ;+/1/

+/ Cata""o! W V and Vun#! T ;1&&,ana(ement! 1,;:


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++ Chu! . B! in(! H! u! ) @! Lhou! 4! un! . and Vurci#! B ;+//7

project on treatment of dye by hydro-dynamic cavitation process

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