Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "i "ioc#emical $% $%&gen De Demand E% E%periment
Semester
2
1.0 Introdu Introducti ction on
Microorganisms such as bacteria are responsible for decomposing organic waste. When organic matter such as dead plants, leaves, grass clippings, manure, sewage, or even food waste is present in a water supply, the bacteria will begin the process of breaking down this waste. When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live. Biochemical oxygen demand or BO is a procedure to determine the amount of oxygen consumed by the microorganisms in the waste water chemically. !t is commonly used as the indicator to show the cleanliness of the waste water. 2.0 Objective
"o measures the strength of the water sample #water, wastewater, etc.$ based on the amount of oxygen needed neede d to stabili%e the organic matter in the sample. • •
"o assess the quality of surface waters. "o understand the characteristics of O contained in water and wastewater.
2.0 Equipment Equipment and Material/Re Material/Reagent agent 1.
5 units o !00 ml "O# bottles
2. Incubato Incubatorr$ capab capable le o main maintain taining ing 20 20 % 1&'
BOD EXPERIM EXPERIMENT ENT |ENVIR |ENVIRONM ONMENT ENTAL AL ENGINE ENGINEERIN ERING G LAB REPOR REPORT T
1
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "i "ioc#emical $% $%&gen De Demand E% E%periment
Semester
2
!. 100 ml be bea(er
). 100 ml grad gradua uated ted c*lind c*linder er
5. 2 units units o 25 25 ml mea meani ning ng pipe pipette ttess
BOD EXPERIM EXPERIMENT ENT |ENVIR |ENVIRONM ONMENT ENTAL AL ENGINE ENGINEERIN ERING G LAB REPOR REPORT T
2
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
+. #O meter
,. p- meter
. ospate "uer
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
3
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
issolve &.' g of KH 2 PO 4 , ().* g of K 2 HPO 4 , ++. g of Na2 HPO4 and ).* g NH 4 Cl of in deioni%ed water. -dust p/ to *.(, if necessary, with either ) 0
H 2 SO4 or 0aO/. ilute to one liter.
. Magnesium ulpate issolve ((.' g Mg SO4 .7 H 2 O and dilute to one liter.
10. 'alcium 'loride issolve (*.' g CaCl 2 and dilute to one liter.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
4
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
11. 3erric 'loride
issolve 1.(' g Fe Cl3 .6 H 2 O and dilute to one liter.
0O"23 "o prepare dilution water, add ) ml of each of the four solutions listed above to one liter of deioni%ed water. 4aturate with O by drawing a vacuu m through the solution.
).0 Metods and rocedure
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
5
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
). '11 ml of waste water is collected from "asik 5+ using a beaker. (. "he sample water is then tested by using p/ meter. !t is tested to be neutral. "he readings of both p/ and temperature are recorded in the Bench 4heet. /owever, if the sample is not neutral, pre6treatment process has to be done to neutrali%e the sample. 7rocedure for neutrali%ing samples3 a$ 7our '1 m8 of samples into a )11 m8 beaker. b$ Measure the p/ of the sample using a p/ meter. !f the p/ is out of the range of p/ 9.1 to p/ &.1 continue with steps + : 9, otherwise perform the BO test on the untreated sample. c$ -dd ) 0 sulfuric acid if the sample is alkaline, or )0 sodium hydroxide if the sample is acidic, until the p/ reaches *.1. d$ ;alculate the amount of sulfuric acid or sodium hydroxide needed to neutrali%e )111ml of the sample. e$ -dd the calculated amount of acid or base to the sample. f$
. . - magnetic stirrer is then added into these two bottles respectively. "he sample in the bottle is stirred whilst the O #issolved Oxygen$ meter is put into the bottle to get the O reading.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
6
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
5.0 Results and 4nal*sis
"'$CE'C*+ $,-GE. DE*.D ( "$D) Analyst: Date! 2//2016 ime ! 110 am Sample Details: Source! G lae
0
p
C
61
250
Pretreatment: *lalinit&/*cidit& Sample 3olume ! 500 m+ ' . .ao ! 0 m+ ' . .2S$4 ! 0 m+
Comments!
.eutral #is is ecause t#e sample ater #as a p of 61
#ic# is considered as neutral (65 7 5) 8 neutral
Sample &pe
Sample 'D
3olume Sample ( m+)
Dilution 9actor
'nitial D$ (mg/+)
9inal D$ ( mg/+)
D$ Depletion ( mg/+)
"$D (mg/+)
"lan
2 ml
0006
:1
66
025
1
"lan
2 ml
0006
:
4
06
5
"lan
2 ml
0006
;1
2
05;
;65
"$D1
"$D2
"$D
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7
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
Average BOD ( s#o t#e calculation)
Cancelled Data/
"$D2
8 5 mg/+
"$D
8 ;65 mg/+
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
8
+.0
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
#44 46478I
+.1 'alculate or te average "O#9 37.31
-verage ?
+ 53.73 + 86.57 3
? '@.(1 mgA
+.2 o: all te calculation and state i an* o te data needs to tro: out.
O epletion # mgA8$ ? !nitial O : inal O O)
? *.@) : *.99 ? 1.(' mgA8
O(
? *.*@ : *.+ ? 1.+9 mgA8
O+
? *.&) : *.(+ ? 1.'& mgA8
BO' ? !nitial O : inal O 7 BO) ? 1.('A1.119* ? +*.+) mgA8
BO( ? 1.+9A1.119* ? '+.*+ mgA8
BO+ ? 1.'&A1.119* ? &9.'* mgA8
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
9
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
+.! e dilution :ater blan( cannot deplete more tan 0.2 mg/7. ;as tis criteria met9
"he BO blank did not show a O depletion of more than 1.( mgA8 after the five day incubation period. - drop of more than 1.( mgA8 indicates some type of contamination or calibration error. 4o the criteria is met. +.) #oes *ou sample so:s 9
"he sample is not showing any toxic effect, it is because the waste water, took from a lake is not a toxic source. -nd the p/ value of the sample is nearly neutral. !t means that the sample doesn>t show any toxic effect. +.5 'ould *ou rel* on *our "O# results9 ;*9
Ces, because the average BO result is compared with the effluent standard #O2, Malaysia$
+.+ "* reerring to e:age/Eluent tandard ?#OE$ Mala*sia@ could *our sample be discarge to river untreated9 I not$ suggest te associated treatment or "O# removal.
-ccording to the 4ewageA2ffluent 4tandard #O2,Malaysia$, the sample cannot be discharge to the river untreated because the value obtained with ( ml of wastewater is higher than '1 mgA8
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
10
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
,.0 #iscussion
D). a@ 'alculate te min / ma= volume o sample to be added to prepare as estimated "O# ?mg/7@
2xample3 -ssume that the estimated BO of an influent sample is 11mgA8. "he .O. of saturated dilution water is approximately &.1mgA8. .O. depletion to be at least (.1mgA8 after ' days of incubation and the residual .O. to be at least ).1mgA8. 4ample Water, m8
(min / max allowabledepletion, mg / L) x ( vol of BOD bottle, mL) ? Etimated BOD ( mg / L )
4ample water minimum, m8
?
2 mg / L x 300 mL 400 mg / L
? ).' m8 Max allowable depletion ? #4at .O. concentration$ : #Min residual concentration$ ? #&.1 : ).1$ mgA8 ? *.1 mgA8 4ample water maximum, m8 7 mg / L x 300 mL
?
400 mg / L
? '.(' m8
b@ ;* must samples containing cautic al(alinit* or acidit* be adjusted beore preparing dilution9
"he BO dilution must be natural which range between p/ values of 9.' to *.' because microbes are most active in this range of p/ value.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
11
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
c@ e completed composite sample arrive in te lab at 11.!0 4.M $;ednesda*$ 2 Marc 201+.;at is te latest da* and time te sample can be started or "O#.
"he sample must be prepared not more than ( hours. !f it is begin within ( hours of collection, cold storage is unnecessary but, if the test will begin within more than ( hours, the sample must keep at or below ℃ during compositing
d@ #escribe te unction o "O# bottle>s cap and seal :ater.
"he function of BO bottle>s cap and seal water is to avoid drawing air into the dilution bottle and reduce evaporation of the water seal during incubation. !t was used to ensure that no air bubble is trapped in the bottle that will affect the characteristics of sample. !t is also to prevent further oxygen dissolving in. Otherwise, bottle>s cap was using to reduce evaporation of the water seal during evaporation.
D(. a@ ;* must samples containing residual clorine be declorinated beore preparation o "O# dilutions9
"o determine the amount of valuable bacteria from its sources. ;hlorine can kill the microbes live and bacteria in samples. b@ ;at reagents are required to cemicall* declorinate a "O# sample9
4ulphuric acid solution or acetic acid solution, potassium iodide solution, sodium sulphite #0a(4O+$
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
12
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
c@ ;at must be done to samples :ic ave been declorinated or adjusted or pvariations9
"he samples which have been dechlorinated must be seeded with +11m8 of BO water in the BO bottle before allows it store in the BO incub ator.
D+. a$ tate te ormula to calculate i
seed correction
BOD5 of eed mate!ial x vol"me of ample 4eed correction ? ii@
300
"O#5 ?seeded@
BOD 5 #mg A8$ ?
[ ( D1− D2 )−( B1 −B 2) ] P
WhereE
D1 ? O of diluted sample immediately after preparation, mgA8 D2 ? O of diluted sample after ' days incubation at (1 ;, mgA8 ⁰ 7 ? decimal volumetric fraction of sample used
b$ ;alculate the seed correction and BO' #seeded$ for the data given as below
ilution
"O#5 o eed Material m8 of seed material
5 mg/7 ( m8
m8 of sample 4tart .O. inal .O.
)11 m8 *.& mgA8 (.@ mgA8
F)
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
13
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
olution 3
BOD5 of eed mate!ial x vol"me of ample 4eed correction
?
300
95 x 2
?
300
? 1.9+++ mgA8
BOD 5
D1 − D2 #mgA 8$
?
2
7?
P ?
100
0.02
(7.8 # 2.9 ) ?
0.02
? (' mgA8
D. a@ !0 m7 o :aste:ater are placed in a !00 m7 "O# bottle. e sample is diluted to ill te bottle. e #O concentrations at te beginning and te end o 5Ada* incubation period are ,.! mg/7 and 1. mg/7 respectivel*. ;at is te "O#9 olutionB
7?
30 mL 300 mL
? 1.)
BOD 5
D1 − D2 #mg A8$ ?
P
=
7.3 −1.8 0.1
=55 mg / L
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
14
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
b@ e "O# 5 o a :aste:ater :as determined to be 250 mg/7. I te reaction coeicient :as 0.2! l/d$ calculate
i$ ultimate BO,
L0=
$ m −%t
1− e
250
¿
− 0.23 ( 5)
1 −e
¿ +9' mg / L
ii$
BOD 3 and BOD t = L 0 ( 1− e
)
−%t
BOD 3=365 ( 1− e
−( 0.23 ) (3 )
)
¿ 181.9 mg / L
iii$ BO remaining at + days
BO' G BOD 3 ?
BOD 8=365 ( 1− e
BOD 8 # BO at & days$
−( 0.23 ) (8 )
)
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
15
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
¿ 301 mg / L C5. a@ ;at is seeding process in "O# measurement9
4eeding is a process of adding live bacteria and microorganism to a sample. !f the samples tested contain materials which could kill or inure the microorganisms, the condition must be corrected and healthy active organisms added.
b@ E=plain preparation o seed material.
•
4elect a material to be used for seeding which will have a BO of at least )&1 mgA8. "his will help ensure that the seed correction meets the 1.9 mgA8 minimum
•
specified in H4tandard MethodsI. 7lace the material in a suitable container and incubate at (1J; for (hours. Ksually, settled raw domestic sewage prepared in the manner above will have sufficient BO for use as a seed material. !f not, small quantities of digester supernatant, return activated sludge, or an acclimated seed material can be used to increase the potency of the seed material used for the test. -s an alternative, commercially available seed material may be used. "he seed correction should not exceed ).1 mgA8 BOE therefore, care should be taken not to use too strong a seed material for the test.
•
"he key to a good seed correction is a relatively stable seed material which produces a good seed correction in every test situation c@ ;at materials can be used to seed a "O# sample
-ny source of water which can provide a suitable population of organisms can be used, however, settled raw sewage or commercially prepared seed material are the most common sources
C+. ;at is te signiicance o dissolved o=*gen 9
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Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
issolved oxygen allows animals to breathe in water and it provides a suitable habitat for the other animals. Bacteria in the water also use this oxygen to break down animals and plants. "he oxygen level is not very high in most water sources. !f the oxygen level is reduced, the animals begin to die. !t is also to maintaining the aquatic life and aesthetic quality of streams and lakes. C,. a@ ;it regard to precision$ ten percent duplicate or replicate samples sould be run. is :ould result in one duplicate sample or one replicate sample being run ever* ten samples. #ierentiate replicate and duplicate sample •
uplicates are two Lor more lab analyses on the same water sample. uplicates are
•
used to determine the N difference between two samples in order to estimate the error involved in the analyses.
b@ ;en are #O levels at teir igest and teir lo:est and :*9
O levels are the highest if the sample of water is not polluted means there is no toxic and bacterial effect ."herefore, the sample of water has a lot of oxygen demanding wastes that well within self6purification capacity. Otherwise, the BO level will be low which indicates the water sample does not have any sign of live microbes. "hen, O levels are low if the sample water does not have enough oxygen to dissolve in water that is needed by all living things.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
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Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
.0 'onclusion
"he result shows that in + beaker of BO, the highest O is BO beaker +. "his show that the higher the O depletion the higher the BO. !n this + beaker of sample has the same amount of volume sample which is (m8. "he initial of the O between the beakers is different. O depletion that we get is final O minus with initial O. "his show that the higher the O depletion the higher the BO. BO in beaker ) has the smallest O depletion and beaker ( was in between beaker ) and beaker +. -fter that, we find the average of the result that we get. !n beaker ), we got +*.+)mgA8. !n beaker (, we got '+.*+mgA8. While in beaker +, we got &9.'*mgA8. "hen we plus this + result and divide by + to get the average result and we get '@.(1mgA8. in this + beaker of sample has the same amount of volume sample which is (m8. "his show that the amount of oxygen needed to stabili%e the organic matter in the sample based on the measurement of strength of the water sample.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
18
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
.0 4ppendi=
7icture ) shows four BO bottles, which for the BO bottle ), ( and + are the mixture of water samples and dilution water while BO bottle is only dilution water.
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
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Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
7icture ( shows one of the group members was measured the p/ value of the sample.
7icture + shows all the BO bottles were placed in the incubator for 5 da&s #ic# capale
of maintaining 20 > 1 0c
BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT
20
Centre for Diploma Studies
Group
2 (Section 1)
Department of Civil Engineering
Session
2015/2016
itle! "ioc#emical $%&gen Demand E%periment
Semester
2
7icture ' shows our group members measured the 7/ value of each sample in BO bottles after ' days placed in an incubator.
10.0 Reerence
)$ avis - ;ornwell, Macken%ie 8 avis. !ntroduction to 2nvironment 2ngineering. +rd 2dition. Mc5raw /ill, (1)1. ($ issolved Oxygen #Wikipedia$. http3AAen.wikipedia.orgAwikiAissolvedPoxygen #-ccessed (1)96()6+$
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