FACUL ULTY:ENGI NEERI NG TECHNOLOGY LABORATOR ORY:CI VI L ENGI GI NEERI NG TECHN HNOL OLOGY EXPERI MENT:CHE HEMI MI CAL OXYGEN DE DEMA MAND ( COD)
EDI TI ON: REVI SI ON NO: EFFECTI VE DATE:
2 FEB 2015
AMENDMENTDATE:
FACULTYOF OFENGI NEERI RI NG TECHN HNOL OLOGY GY DEPARTME MENT OFCI VI LENGI NEERI RI NG TECHN HNOL OLOGY
ENVI RONM ME ENTALENGI GI NEERI NG TECHNO OL LOGY LABORATORY LABORATORY I NSTRUCTI ONSHE HEETS
COURSECODE
BNP20503
EXPERI MENTCODE
EXPERI MENT3
EXPERI MENTTI TLE
CHEMI CALOXYGEN DEMAND ( COD)
DATE GROUPNO.
Aas 15/3/2015 2
LECTURER/I NSTRUCTOR/TUTO R
1 1)Mi ssNadzi r ahBi nt iZayadi 2)Mi s sI z z a t iI z wanniBi nt iI br a hi m
DATEOF OFREPORTSUBMI MI SSI ON ATTENDANCE/PARTI CI PATI ON/DI SI PLI NE: I NTRODUCTI ON:
/5%
PROCEDURE:
/5%
RESULTS& CALCULATI ONS
/15%
ANALYSI S DI STRI BUTI ON OFMA MARKSFOR DI SCUSSI ONS: LABORATORYREPORT ADDI TI ONALQUESTI ONS CONCLUSI ON
/15% /20% /15% /10%
SUGGESTI ONS& RECOMENDATI ONS
/5%
REFERENCES:
/5%
TOTAL: EXAMI NER COMME OMMENTS:
/5%
/100%
RECEI VED DATE AND STAMP:
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FACUL ULTY:ENGI NEERI NG TECHNOLOGY LABORATOR ORY:CI VI L ENGI GI NEERI NG TECHN HNOL OLOGY EXPERI MENT:CHE HEMI MI CAL OXYGEN DE DEMA MAND ( COD)
EDI TI ON: REVI SI ON NO: EFFECTI VE DATE:
2 FEB 2015
AMENDMENTDATE:
STUDENT COD ODE OF OFETHI HI CS DEPART RTME MENT OF CI VI LENGI NEERI RI NG TECHNOL OLOGY
FACULTYOF OFENGI GI NEERI NG TECHN HNO OL LOGY
Ihe r e bydec l ar et hatIhav epr e par edt hi sr e po r twi t hmyo wn wne ffor t s.Ia l s oadmi tt o notac c e pto rpr ov i deanyass i s t anc ei npr e par i ngt hi sr e po r ta ndany t hi ngt hati s i ni ti st r ue. 1)Gr oupLeader Na me me : Mat r i xNo . :
___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ( Si gnat ur e) _ __ _ _ _ __ _ _ _ _ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
2)Gr oupMemb mber1 Na me me : Mat r i xNo :
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ( Si gnat ur e) _ __ _ _ _ __ _ _ _ _ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
3)Gr oupMemb mber2 Na me me : Mat r i xNo .:
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ( Si gnat ur e) _ __ _ _ _ __ _ _ _ _ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
4)Gr oupMemb mber3
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ( Si gnat ur e)
2
FACULTY:ENGI NEERI NG TECHNOLOGY LABORATORY:CI VI L ENGI NEERI NG TECHNOLOGY EXPERI MENT:CHEMI CAL OXYGEN DEMAND ( COD)
EDI TI ON: REVI SI ON NO: EFFECTI VE DATE:
2 FEB 2015
AMENDMENTDATE:
3
1. 0 OBJECTI VES a)To de t e r mi ne t he c he mi c alox y g e n demand ( COD)i n wat e r /was t e wat er sampl e. b)To compar et he l abor at or yr es ul t be t we e n i nflue nt and e fflue nt of wat e r /was t e wat e rs ampl e .
2. 0LEARNI NG OUTCOMES Att hee ndoft hi scour s es t ude nt sar eabl et o: a)Under s t and t he c onc ept of c hemi c al oxy g e n de mand i n a gi v e n wat e r /was t e wat e rs ampl e . b)I de nt i f yt hepr i nci pl eofdi c hr omat er e fluxandr e act ordi g e s t i onme t hodst o de t er mi neCOD. c)Eval uat et hewat erpar amet erqual i t yi n domes t i cwast ewat ersampl eand wat e rsuppl y . d)I de nt i f ypr o bl e msa ndus et he i rg e ne r i cs ki l lt os ol v epr o bl e ms . e) Devel opt hei rabi l i t yt owor ki ngr oup.
3. 0I NTRODUCTI ON Thepr i nc i pl eoft hi se xpe r i me nti st oc ompl e t e l y oxi di z et heor g ani c mat t er pr es ent i n sampl e by pot ass i um di c hr omat e( K2Cr n t he 2O7) i s ul phur i ca c i d( H2SO4)me di um and t heex ce ssK2Cr i sdet er mi ned by 2O7 t i t r a t i o n ag a i ns tf e r r o usammo ni um s ul phat e ,us i ngf e r r o i ni ndi c at o r .The di chr omat econsumed by t hesampl ei sequi val entt ot heamountt ot he amountofO2 r e qui r e dt oo xi di z et heor g ani cmat t e r . Chemi caloxy ge n demand ( COD)t es ti suse d wi del yt o meas ur et he pol l ut i on st r engt h of domest i c and i ndust r i al wast ewat er s. I t sai dt o me as ur e t he c apac i t y of wat e r t o cons ume oxy g e n dur i ng t he decomposi t i on oforg ani cmat t erand t heoxi dat i on ofi norg ani cchemi cal s such asammoni aand ni t r i t e.Thedi chr omat er efluxmet hod i spr ef er r ed ov er pr oce dur es usi ng ot her oxi dant s( e. g. pot ass i um per manganat e) be caus eofi t ssupe r i oroxi di z i ngabi l i t y ,appl i c abi l i t yt oa wi dev ar i e t yof sampl esandeaseofmani pul at i on.Oxi dat i on ofmostor gani ccompounds i s95–100% o ft het he or e t i c alv al ue . 1
4. 0I NSTRUMENTS/APPARATUS/CHEMI CAL/REAGENTS 4. 1Chemi cal s/Reagent s 4. 4.Cl osedReflux,Ti t r i met r i cMet hod( Pr eparedbyTechni ci an) nc ar r y i ngoutt hef o l l o wi ngpr o ce dur e s ,us epr o pe rs a f e t y Caut i on:I me as ur e s ,i nc l udi ngpr o t e c t i v ec l o t hi ng ,e y epr o t e c t i o nandaf ume hood.Reagent sc ont ai ni ngheavymet al s( HgSO4 andAg2SO4)s ho ul d bedi s pos e dofast oxi cwas t es .
( a)Pot assi um di chromat e( K2Cr ,( COD di gest i onr eagent ) : 2O7) ( i ) 10. 216gofov endri ed( pri marys t andar dgr ade,pre vi ousl y dri edat103oC pot assi um di chr omat e( K2Cr i swe i g he d 2O7) ( i i )
outi nt oa1l i t r ebe ake r . 30gofmer cur i cs ul phat ei swei ghedouti nt oa250ml
be ake r . ( i i i ) At r ayofi cei spl acedonamagnet i cst i rr eri nt hef ume ( i v)
cupboar d. Bot hbeaker sar et r ansf er r edt ot hef umecupboar d;t he1 l i t r ebe ake ri sputi nt ot hei c et r a yandas t i r r e rbari s
( v)
added. Appr ox.500mlofdi st i l l edwat eri saddedt ot he1l i t r e be ake r .Be gi ns t i r r i ngandt hemer c ur i csul phat ei s gr adual l yaddedandt he250mlbeakeri sr i nsedi nt ot he
( vi )
o t he rwi t hdi s t i l l e dwat e r . Acl ean,drymeas ur i ngcy l i nderi suse dt omeas ur eout167 mlofconcent r at edsul phuri caci d( Usea500mlbot t l eand
wi pebe f or eandaf t e rus e ) . ( vi i ) Theaci di saddedt ot hemi xt ur eabout10mlatat i me, s t i r r i ngc o nt i nuous l y . ( vi i i ) Themi xt ur ei sal l owedt ocoolt oroom t emper at ur e,and ( i x)
t he nr e mo v et hes t i r r e rba r . Usi ngaf unnel ,t hemi xt ur ei spour edi nt oa1l i t r e v ol ume t r i cflask,r i ns i ngt hebe akeri nt ot heflas kunt i lal l
( x)
r esi duesar er emoved. Makeupt o1l i t r ewi t hdi st i l l edwat er .Topsec ur el yand i nv e r tt omi x . 2
( xi )
Thecont ent soft heflaskaret r ansf er r edi nt ot hecor r ect COD r eage ntdi spenser .
( b)
Sul phur i caci d( H2SO4)/si l versul phate( Ag2SO4)sol ut i on( COD : catal ystr eagent ) ( i ) 22.5gofsi l ve rsul phat ei swei ghedouti nt oa250ml beake r . ( i i ) Af ul l2. 5Lbot t l eofconcent r at edsul phuri caci di s ( i i i )
col l ect edf r om t heaci dcupboar d. Thet opi scar ef ul l yr emovedf r om t heaci dbot t l eanda
( i v)
po wde rf unne li si ns e r t e d. Thesi l versul phat ei st i ppedi nt ot hef unnel ,t hef unneli s t appedt or el easet hepowderst i cki ngt oi t .DO NOTADD WATER.Whe nr emov i ngt hef unne le ns ur et hati ti sf r e e
( v)
f r om aci d. Anyr emai ni ngsi l v ersul phat ei nt hebeakeroront he f unnelshoul dbewasheddownt hesi nkwi t hpl ent yofcol d
wat er . ( vi ) Thesol ut i oni sl ef ti nasaf ecupboar df or24hour s,and mi xedt hor oughl ybef or euse.
( c)
Fer r ousammoni um sul phat e( FAS) ,Fe( NH4) SO4) 2( 2, ( i ) I nt ot he 600 ml be ake r , 9. 8 g of Fe r r ous Ammoni um ( i i )
Sul phat e( FAS)i swei ghedout . Appr ox.300mlofdi st i l l edwat eri saddedandst i r r edwi t ha
( i i i )
g l a s sr o d. 25 mlofco nc.sul phur i c aci di s meas ur ed outusi ng t he
( i v)
measur i ngcyl i nder . The aci di s pour ed i nt ot he beaker ve r y sl owl y , whi l s t
s t i r r i ng. ( v) Ensur et hatal lt heFAShasdi ss ol v ed. ( vi ) Thebeakeri sal l owedt or eac hr oom t emper at ur e ( vi i ) Thesol ut i on i spour ed i nt oa 1 l i t r evol umet r i cflask vi aa f unneland t hebeakeri sri nsed i nt oi t .Makeup t o1 l i t r e wi t hdi s t i l l edwat e r .
3
e r i o r at i o no fFASc anbede c r e a s edi fi ti ss t o r e di nadar k Not e:Thedet bot t l e .
( d)
485gof1,10phenant hr ol i ne Ferr oi ni ndi cat orsol ut i on:1. monohydr at e( C12H8N2. H2O)and0. 695goff er r ousammoni um s ul phat ehe pahy dr at ear edi s s ol v e di ndi s t i l l e dwat e ra nddi l ut et o appr oxi mat el y100mL.
4. 1. 2
Cl osedReflux,Col ori met r i cMet hod
i ) COD di gest i on r eagentvi al swi t hal lpr emi xedr eagent si ncl uded( e. g. Hach COD di ge st i on vi all ow r ange and COD di ge s t i on vi alhi gh r ange)
4. 2.Appar at us/I nst r ument s 4. 2. 1 Cl osedReflux,Ti t r i met r i cMet hod g e s t i on v e s se l s :{ r e f e r e abl yus ebor os i l i c at ec ul t ur et ube s( at i ) Di l eas t16mm x100mm)wi t hTFEl i nedsc r e w caps . ockheat ert ooper at e150 ± 2 C wi t h hol e st oac c ommodat e i i )Bl °
di g es t i onv e ss el s pet t es( 10,25and50mL) i i i )Pi et t e( 50mL) ,bur et t est andandcl amp i v)Bur v ) Anal yt i c albal ance v i )Spat ul a v i i ) Vol ume t r i cflas k v i i i ) Magne t i cs t i r r erands t i r r i ngbar s i x)Measur i ngcyl i nder x)Be ake r s xi )Coni c alflas k
4. 2. 2. Di ges t i on vessel swi t hpremi xedr eagentsmet hod i ) Bl ockheat ert ooper at e150±2 C wi t hhol est oacc ommodat e °
di g es t i onv e ss el s . i i )Spect r ophot ome t er( DR6000) i i i )COD di g e s t i o nr e ag e ntv i al s i v )T e s tt uber ac k v ) Wi pet i ss ue
4
5
PROCEDURE 5. 1 Cl osedReflux,Ti t r i met r i cMet hod er r ousammoni um 5. 1. 1. Standardi zati on ofFASsol ut i on T : hef s ul phat e( F AS)s o l ut i o nmus tbes t a nda r di z e dbyt hef o l l o wi ng pr ocedur e: T e anbur e t t ei spr e par e d.Thecl e anbur e t t ei sr i ns edwi t h ( i ) . hecl FASt hr e e( 3)t i me s )pr i ort ofil li ti nwi t hFAS. 5mlofdi gest i onr eagenti sdi spensedi nt oabeakerand ( i i ) . t hen10mlofdi st i l l edwat eri saddedandmi xed. ( i i i ) . Tot hemi xt ur ec ar e f ul l yandv e r ys l owl yadd3. 5mlof c a t a l y s t . ( i v ) . 2dr o pso ff e r r o i ni ndi c at o ri sadde dandt i t r at e dwi t hFAS unt i lt hes o l ut i o nt ur nsr e d.Co l o urc ha ng ewi l lbeo bs e r v e das f o l l o ws :y e l l o w>g r e e n>bl ue>r e d. ( v ) . Thei ni t i alandt hefinalr e adi ngofFAS( t i t r e )i sr e c or de dand
e6. 1. use di nTabl
5
6
7
8
9
10
11
5. 1. 2.
Di ges t i on
g es t i on bl oc ki st ur ne d on af t erc he c ki ngt hati ti sc l e ar ( i ) Thedi ( i i )
f r om chemi calcont ami nat i on. The di ge s t i on t ubes t o be use d ar e ensur ed t hatc ompl e t el y
( i i i )
i nt ac t ,wi t hnoc r ac ksorc hi ps . Usi ngt heaut odi spenser ,1. 5 mlofdi gest i on sol ut i on i spl aced
( i v) ( v)
i nt oadi g e s t i o nt ube . Add2. 5mlofsampl eusi ngapi pet t e. Usi ng t heaut odi spense r ,3. 5 mlofcat al ys ts ol ut i on i sadded v er ys l owl y ,s ot hati tf or msal ay e ratt hebot t om oft het ube .
12
( AT THI S POI NT THE TUBE CONTENTS WI LL UNDERGO ( vi )
RAPI D TEMPERATURE I NCREASE) . St eps 3 t o 5 ar er epeat ed f oral lsampl esi n dupl i cat eand 1
bl anks( di s t i l l e dwat eri nt hepl ac eofs ampl e) . ( vi i ) Thet ubecapi schec ked t oensur et hePTFE i nse r ti spr es ent , and t het ubei scapped ve ryt i ght l y .Hol dt het ubebyt hecap f r om t hi spoi ntonwards. ( vi i i ) Cont ent saremi xedbyshaki ngf r om si det osi de( donoti nver t ) . ( i x) Al lt ubesarepl aced i nt hedi ges t i on bl ock,cove rwi t h per spex ( x)
coveranddi gest edf ort wohour s. Thet ubesar er emov edf r om t hebl oc kandal l ow t hem t oco olt o r o om t e mpe r at ur ebe f o r et i t r a t i ng .
5. 1. 3 Ti t r at i on ( i ) Thec ont ent sofadi ge s t i ont ubear epour edi nt oacl ean100ml c o ni c alfla sk.Thet ubei nt ot hefla s ki sr i ns e dt wi c ewi t h ( i i )
di s t i l l e dwat e rt oe ns ur eal lt heco nt e nt sar et r ans f e r r e d. Two( 2)dr opsoff err oi ni ndi cat ori saddedandt i t r at ewi t hFAS
( i i i )
unt i lt hec o l o urc hang e st or e d. Le tt het i t r e( F AS)f o rbl a nks=Amlandt het i t r ef o rt he sampl es=B ml .Thei ni t i alandt hefinalr eadi ngofFASare
Tabl e6. 2and6. 3. r e c o r de di n
5. 2 Cl osedReflux,Col or i met r i cMet hod 5. 2. 1 Di gest i on ( i )TheCOD r eac t ori st ur nedonandpr eheat edt o150oC. ( i i )Thec a pso fCOD di g e s t i o nr e ag e ntv i a l sa r er e mo v e df o rt he appr opr i at erange. ( i i i ) Thev i ali she l data45o ang l e .Pi pe t t e2. 0mL( f o rl o wr ang e ) a nd0. 2mL( f o rhi g hr a ng e )o fs ampl ei nt ot hev i a l s . ( i v ) Thev i al sar ec appe dt i g ht l y .Theout s i deofCOD v i ali sr i ns e d wi t hde i oni s e dwat e randt hev i ali swi pe dc l eanwi t hpape r t o we l . 13
( v T ) hevi ali she l dbyt hec apandov eras i nkandi nv er t e dg e nt l y s e v e r a lt i me st omi xt hec ont e nt s .Thev i ali spl ac e di nt he pr eheat edCOD r eact or . ( v i ) A bl ank i spr e par e d by r e pe at i ng s t e ps( b)t o( e ) ,s ubs t i t ut i ng 2. 0 mL ( f orl ow r ange)and 0. 2 mL ( f orhi gh r ange)dei oni sed wat e rf ort hes ampl e .Thevi al she at e df or2hour s. ankmustr unwi t heachsetofsampl es . Not e:Onebl ( v i i ) Ther e ac t ori st ur ne d off.Wai tabout20 mi nut e sf ort he v i al st oc oolt o120oC o rl e s s . ( vi i i ) Each vi ali si nver t ed sev er alt i messt i l lwarm.Thevi al s ar epl acedi nt oar ackandcoolt or oom t emper at ur e. ( i x)Pr oceedt ot hecol ori met r i cdet ermi nat i ont omeasur et heCOD. eat eraccur acy ,anal ysea mi ni mum oft hr eere pl i cat esand Not e:Forgr a v e r ag et her e s ul t s .
COD r eac t or
5. 2. 2 Col ori met r i cdet ermi nat i on ( i )Pr oce dur ei sbasedonHac hme t hod8000,use donHac h DR6000spec t r ophot omet er . ( i i )Sel ec tpr ogr amme:430COD LR or435COD HR.Touchst ar t . ( i i i ) Cl e ant heout s i deoft hev i alwi t hawi pet i s s uet or e mo v e finger pr i nt sorot hermar ks. ( i v ) Thebl anki spl ac e di nt ot hec el lhol de r . ( v)TouchZer o.Thedi spl aywi l lshow:0mg/LCOD. ( vi )When t he t i mer bee ps, The sampl e vi al i s pl ace di nt ot he sampl ecel lhol der .Resul t swi l lappeari nmg/LCOD andr ecor d
Tabl e6. 4. t her e s ul ti n
6
RESULTS CALCULATI ONS 6. 1 Res ul t s
14
Tabl e6. 1:FASst andar dt i t r at i on( Cl osedReflux,Ti t r at i onmet hod)
Vol umeof K2Cr used, 2O7 mL
Tabl e6. 2: FAS
5. 0
Vol umeofFASr eadi ng, Vol umeof mL FAS required I ni t i al Fi nal ( T) ,mL 7. 2 15. 0 7. 8
Vol umeof r equi r ed
f orbl ank( Cl osedReflux,Ti t r at i on met hod) Vol umeof Vol umeofFASr eadi ng,mL Vol umeFAS sampl eused, r equi r ed( A) ,mL I ni t i al Fi nal mL 2. 5 15. 0 23. 8 8. 8
Tabl e6. 3:Vol umeofFASr equi r edf orSampl e( Cl osedReflux,Ti t r at i on met hod) TypeofSampl e: Vol umeof Vol umeofFASr eadi ng,mL Vol umeFAS sampl eused, r equi r ed( B) ,mL Fi rs t Last mL 2. 5 23. 8 31. 5 7. 7
Tabl e6. 4:COD concent r at i onofsampl es( React orDi gest i onmet hod)
COD f orl ow r ange,mg/L Bl ank
Sampl e1
0. 0
122. 0
6. 2 Cal cul ati ons
COD,mg/L = ( 000 AB x ) D x1, T 15
Whe r e:A = v ol umeofFASuse df orbl ank,mL B =v ol umeofFASuse df orsampl e,mL T = Vol umeoft i t r e( FAS)t obeusedi nFASst andardi zat i on D =Di l ut i o nf ac t o rf o rs ampl e( i ft hes ampl ene e de dt obe di l ut e d)
COD,mg/L =( 8. 87. 7)x1x1000 7. 8 =141mg/L
7
ANALYSI S Fr om t her esul t ,t hevol umeofFASr equi r edf orFASst andardi zat i on ( T)andt hevol umeofFASusedf orbl ank( A)andsampl e( B)i ncl osedr eflux, t i t r at i onmet hodar eusedt ocal cul at et heCOD val ueoft hesampl ei nmg/L. Thebur e t t er e adi ngsar et akenasfinalr e adi ngoft abl e6. 1,6. 2and6. 3whe n t hecol ouroft hecont ent schangedf r om yel l ow t ored.Theval ueofA,B andT i sc al c ul at e dbyus i ngt hefina lr e adi ngmi nust hei ni t i a lr e adi ngoft he bur e t t er e adi ng.Thev al ueofCOD i sc al c ul at e dbyus i ngt hef or mul agi v e n andi ti s141mg/L.Ther esul tobt ai nedf r om t hecl osedr eflux,col ori met r i c me t hodbyHac hDR6000spe ct r ophot ome t eri s122mg/L.
8
DI SCUSSI ONS
TheCOD t es ti sus e dwi de l yt oes t i mat et heamountofor g ani cmat t e r i nwas t e wa t e r .I ti same as ur e me nto ft heo x y g e ne q ui v a l e nto ft hemat e r i a l s pr e s e nti nt hewas t e wa t e rt ha tar es ubj e c tt oo xi da t i o nbyas t r o ngc he mi c al o xi da nt( i nt hi sc a s e,di c hr o mat e ) .Whe nwas t e wat e rc o nt ai nso nl yr e adi l y
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a v ai l abl eo r g ani cbac t e r i alf o odandnot o xi cmat t e r ,t heCOD t e s tr e s ul t s pr ovi deagoodes t i mat eofBi ochemi calOxyge nDemand( BOD)val ues. Thepr o c e dur eo fc o l o r i me t r i cme t ho di sg r e a t l ys i mpl i fie do v e rt he t i t r i me t r i cme t ho d.Be s i de s ,t hec ol o r i me t r i cme t ho di sus i ng spect r ophot omet ert odet er mi net heCOD val ueandi twi l lmor eaccur at e t ha nt i t r i me t r i cme t ho d.Fo rc o l o r i me t r i cme t ho d,t hec hr o mi um ( I I I )i o ni n t hespeci meni smeasur edbyspect r ophot omet eraf t ert hemi xt ur ehasbeen cool ed.Theexc esschromi um ( I I I )i onshowshow muchchr omi cwasuseby or gani csmat t er .Thepur poseofr unni ngabl anki st ocompensat ef orany e r r o rt hatma yr e s ul tbe c aus eo ft hepr e s e nc eo fe x t r ane o uso r g a ni cma t t e ri n t her e ag e nt s . Ther earef ew r esul t sobt ai nedf r om t heexper i mentbecauset hevi al s st ucki nt heCOD r eact ort hatcausedbyuncl eanofvi al ssur f ace.Ther esul t o ft het i t r i me t r i cme t ho da ndc o l o r i me t r i cme t ho da r ed i ffe r e ntwi t ht hev a l ue of122mg/Land141mg/L.Thi sdi ffer encemayhappenwhent i t r at et he s ampl ewi t hFASs ol ut i o nunt i li tc hang e st or e dc o l o ur .I naddi t i o n,i twi l lbe al a r g edi ffe r e nc ei nt her e s ul ta l t ho ug ht her e a di ngobt a i ne df r o mt i t r a t i o n hasadi ffer enceabout0. 1ml .Thev al ueofCOD gotf r om t hi se xper i mentwas 122mg/Land141mg/Landunderl owr angeofCOD ( <150mg/L) .Bas e don Depar t mentofEnvi r onment ,Mi ni st ryofNat ur alResour cesand Envi r onment ,t heCOD val uesabov et he100mg/Lar ecl assVanduse l es sf or anyac t i v i t i e ss uc hasi r r i g at i o n,fis he r yandwat e rs uppl ybyr e f e r r i ng I nt er i m Nat i onalWat erQual i t ySt andard( I NWQS) .
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ADVANCED QUESTI ONS 1 .Whatwi l lhappe nt ot heCOD v al uei fHgSO4 i snotadded? Chl or i newi l lnotbeseparat edoutoft hesampl eeffluentandt heval ueof COD wi l lbehi ghert hani tshoul dbe.
2. Whatwast hepur poseoft hebl anksampl e?
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Thepur pos eofr unni ngabl anki st oc ompens at ef oranye r r ort hatma y r e s ul tbe c aus eo ft hepr e s e nc eo fe x t r ane o uso r g ani cma t t e ri nt he r e a ge nt s .
3. Whyi si ti mpor t antt ode t e r mi neCOD t e s ti nwas t e wat e rt r e at me nt ? I ti susedt omeasur eordet er mi net heamountofor gani cpol l ut ant sf ound i n surf acewat ersuch asl akesorwas t e wat er ,and make COD a use f ul measur eofwat erqual i t y . i z et he me t hod and wr i t et he c hemi calr eac t i ons i nv ol v ed and 4. Summar i nt e r pr e ty o urt e s tr e s ul t s( Cl o se dRe flux ,Ti t r a t i o nMe t ho d) . Sampl ei sr efluxedwi t hknownamountofexc essdi chr omat ei npr es enceof sul phur i c aci d. Cat al ys ti s use dt o bi nd or compl ex chl or i des. The r emai ni ng di chr omat ei st i t r at ed wi t h FAS t o det er mi ne t hat use df or o xi di z i ngt heor g a ni cmat t e r . 23+ 6Fe2++Cr >6Fe3++2Cr +7H2O 2O7 Fe r r o i ni ndi c at o rg i v e sac ha ng ey e l l o wt or ec ol o uro nc o mpl e t er e duc t i o n ofdi chr omat e.Res ul texpr es se dasmg/LCOD. ei sc ol l ec t e df orCOD anal y s i sand i ti st obeper f or me d on t he 5 .A sampl f ol l owi ngday.Desc r i bet wowaysby whi ch t hesampl ecan bepr ese r ve d. Whyi si tnec e ss ar yt opr es e r v et hes ampl e ? Two way st o pr e se r v e d wat er s ampl e ar e addi ng a l i t t l e bi tac i d and keepi ngsampl esi ni ce.Keepi ngsampl esi ni ceunt i lt heyar esubmi t t edt o t he l abor at ory wi l l pr ese r ve t hem wel l enough f or most t es t s. I ti s nece ssaryt opr eser vet hesampl ebecausei tcan r et ar dt hechemi caland bi ol ogi c alc hang e si nt hesampl e.
10 CONCLUSI ON
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Chemi caloxy ge ndemand( COD)i suse dasameas ur eofoxy ge n r e q ui r e me nto fs ampl et ha ti ss us c e pt i bl et oo xi dat i o nbys t r o ngc he mi c al oxi dant .TheCOD val uef orsampl ei nt hi sexperi mentunderl ow r angeandi t i scl assi fiedascl assVbasedonI NWQS.Hence,wecanconcl udet hatt hi s wat e rs ampl ehashi ghor g ani cmat t er .Las t l y ,COD i st het ot almeas ur e me ntof al lc he mi c al si nt hewa t e rt ha tc a nbeo xi di z e d .
11 SUGGESTI ONSAND RECOMMENDATI ONS Thev i almus tbec l e ane dandr emov edal lt agsont hev i al ’ ssur f ace be f or eput t i ngi nt ot heCOD r eac t orandt het agss houl dbeput t i ngont he capofvi al .Thi sshoul dbeconsi der edapr ecaut i ondur i ngcarryoutt he exper i ment .Theparal l axer r ors houl dbeavoi dedwhent aki ngt her eadi ngof t hebur e t t e .
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REFERENCES
1)Davi es,M. Let .al .Pr i nci pl esofEnvi r onment alEngi neer i ngandSci ence; McGr aw Hi l l ;2004. 2)ht t p: //e duc at i o n. s e at t l e pi . c o m/t i t r at i o ndi ffe r e nt c o l o r i me t r y 4356. ht ml 3)ht t p: //sc i ence . j r ank. or g/pages/1388/Chemi cal Oxyge nDemand. ht ml 4)ht t p: //www. pcd. go. t h/i nf o_serv/en_r eg_st d_wat er 04. ht ml
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s e di ak ano l e h: Pr epar edby/Di angan: Si gnat ur e/Tandat Name/Nama :DR.NORHASLI NAHASHI M i kh: FEBRUARY2015 Dat e/Tar
sahkanol eh: Appr ov e dby/Di angan: Si gnat ur e/Tandat Name /Nama:DR.SURAYAHANIADNAN ar i kh Dat e/ Dat e/T :FEBRUARY2015
APPENDI X:COD PROCEDURE
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