full report bod

8/16/2019 Full Report Bod

http://slidepdf.com/reader/full/full-report-bod 1/21

Centre for Diploma Studies Group 2 (Section 1)

Department of Civil Engineering Session 2015/2016

itle! "ioc#emical $%&gen Demand E%periment Semester 2

1.0 Introduction

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 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 and Material/Reagent

1. 5 units o !00 ml "O# bottles

2. Incubator$ capable o maintaining 20 % 1&'

BOD EXPERIMENT |ENVIRONMENTAL ENGINEERING LAB REPORT 1






!. 100 ml bea(er

). 100 ml graduated c*linder

5. 2 units o 25 ml meaning pipettes







+. #O meter

,. p- meter

. ospate "uer







issolve &.' g of KH 2 PO

4 , ().* g of K 2 HPO

4 , ++. g of Na2 HPO

4 and ).* g

NH 4Cl 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

2O and dilute to one liter.

10. 'alcium 'loride

issolve (*.' g CaCl2 and dilute to one liter.







11. 3erric 'loride

issolve 1.(' g Fe Cl3.6

H 2O 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 vacuum through the solution.

).0 Metods and rocedure







). '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 readingsof 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$ <epeat steps )6' until the p/ test shows p/ *.1.

+. ( ml of sample water is poured into the first, second and the third bottle. "hen, all the

bottle if filled with dilution water until +11ml.Only the last bottle is filled with dilution

water and labelled as =Blank )>.

. - 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. <epeat this step for the second and third bottle.

'. "he readings of O for all three bottles are recorded in the Bench 4heet as initial O,

9. "he bottles are kept in the BO incubator and remained around (1 ℃ .

*. "he final O is recorded after ' days of the experiment.







5.0 Results and 4nal*sis

"'$CE'C*+ $,-GE. DE*.D ( "$D)

Date! 2//2016

ime ! 110 am

Analyst:

Sample Details:

Source! G lae

p 0C

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

3olumeSample( m+)

Dilution9actor

'nitial D$(mg/+)

9inal D$( mg/+)

D$Depletion( mg/+)

"$D(mg/+)

"$D1

"lan 2 ml 0006 :1 66 025 1

"$D2

"lan 2 ml 0006 : 4 06 5

"$D

"lan 2 ml 0006 ;1 2 05; ;65







Average BOD( s#o t#e calculation)

Cancelled Data/ <esult! *verage 8 1 = 5 = ;65 8 5:20 mg/+

"$D1 8 1 mg/+

"$D2 8 5 mg/+

"$D 8 ;65 mg/+







+.0 #44 46478I

+.1 'alculate or te average "O#9

-verage ?37.31+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







+.! 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 <a to=ic eect>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







,.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

?2mg/ L x 300mL

400mg/ L

? ).' m8

Max allowable depletion

? #4at .O. concentration$ : #Min residual concentration$

? #&.1 : ).1$ mgA8

? *.1 mgA8

4ample water maximum, m8

?7 mg/ L x300mL

400mg/ 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.







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+$







c@ ;at must be done to samples :ic ave been declorinated or adjusted or p-

variations9

"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 incubator.

D+. a$ tate te ormula to calculate

i seed correction

4eed correction ?BOD

5of eed mate!ial x vol"me of ample

300

ii@ "O#5 ?seeded@

BOD5 #mg A8$ ?

[ ( D1− D

2 )−( 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

"O#5 o eed Material 5 mg/7ilution

F)

m8 of seed material ( m8

m8 of sample )11 m8

4tart .O. *.& mgA8

inal .O. (.@ mgA8







olution3

4eed correction ?BOD5 of eed mate!ial x vol"me of ample

300

?95 x 2

300

? 1.9+++ mgA8

BOD5

#mgA 8$ ?

D1− D

2

P 7 ?

2

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 ?30mL

300mL

? 1.)

BOD5 #mg A8$ ?

D1− D

2

P =

7.3−1.8

0.1=55mg/ L







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

1−e−%t

¿

250

1−e−0.23( 5)

¿ +9' mg/ L

ii$ BOD3 and

BODt = L0(1−e

−%t )

BOD3=365 (1−e

−(0.23) (3) )

¿181.9mg/ L

iii$ BO remaining at + days

BO' GBOD

3 ? BOD8 # BO at & days$

BOD8=365 (1−e

−(0.23) (8 ))







¿301mg / 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







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

• <eplicates are two or more separate water samples collected in the field from the

same site and depth. <eplicates are used to determine the errors involved in sample

collectionE if there are no errors in the collection and analysis, and then the difference

between two replicate analyses indicates the natural variability in the water at that

location.

• 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.







.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.







.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.







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# capaleof maintaining 20 > 1 0c







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+$


http://en.wikipedia.org/wiki/Dissolved_oxygen

http://en.wikipedia.org/wiki/Dissolved_oxygen

full report bod

Documents