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1.0 ABSTRACTThe main of objective of this experiment is to
determine the amount of organic pollutant in water
and wastewater. In this experiment, we studies about how to
determine the biochemical oxygen
demand (BOD5) in water and wastewater. This has been done by
using dilution method. First of
all we have to prepare the reagents such as phosphate buffer
solution, magnesium sulfate
solution, calcium sulfate solution, ferric chloride solution.
After that, the dilution water was
prepared by adding 1mL each of phosphate buffer, magnesium
sulfate, calcium chloride, ferric
chloride solution into 1L volumetric flask and distilled water
was added to 1L .The wastewater
sample was added into a 500 ml beaker. Meanwhile, the dilution
water was add up into
300ml.The ph value we get is 6.87 after we adjust the ph by
adding an acid. 300 ml of dilution
water as control was prepared in another 500ml beaker. Then, all
the prepared samples and
control was filling in 300 ml incubation bottle and we measure
the (DO 1) concentration for each
sample using Dissolve Oxygen Meter. These bottles were left
until 5days to get another (DO2)
reading. From the experiments, we get the BOD5 value for the
control is -13.8 mg/L, while the
sample is 198 mg/L. This value is too far away when comparing to
the Environmental Quality
ACT 1974 with standard A and B are 20 and 50. This is due to
some error during conducting
the experiments which is the wastewater sample was keep too long
before using it, thus this
may affect the result of the experiments
2.0 INTRODUCTION
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The BOD of water may be defined as the amount of oxygen required
for aerobic microorganism
to oxidize the organic matter to a stable inorganic
form.Standard BOD measurements are made
at 20 C for duration of 5 days.Usually this includes oxygen
required for microbial oxidation of
5days.Usually this includes oxygen required for microbial
oxidation of carbonaceous matter
(CBOD), INORGANIC materials (sulfides,Fe (II) ) and nitrogenous
matter (NBOD).The
biochemical oxygen demand (BOD) determination is empirical test
in which standardized
laboratory procedure is used to determine the relative oxygen
requirements of waste waters,
effluents and polluted water. The test has its widest
application in measuring waste loading to
treatment plants and in evaluating the BOD removal efficiency of
such treatment systems, as
cited by
There are two commonly recognized methods for the measurement of
BOD.The manometric
method and dilution method.
Manometric method
This method is limited to the measurement of the oxygen
consumption due only to carbonaceous
oxidation. Ammonia oxidation is inhibited.
The sample is kept in a sealed container fitted with a pressure
sensor. A substance that
absorbs carbon dioxide (typically lithium hydroxide) is added in
the container above the sample
level. The sample is stored in conditions identical to the
dilution method. Oxygen is consumed
and, as ammonia oxidation is inhibited, carbon dioxide is
released. The total amount of gas, and
http://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Lithium_hydroxidehttp://en.wikipedia.org/wiki/Lithium_hydroxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Ammonia
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thus the pressure, decreases because carbon dioxide is absorbed.
From the drop of pressure, the
sensor electronics computes and displays the consumed quantity
of oxygen.
The main advantages of this method compared to the dilution
method are:
simplicity: no dilution of sample required, no seeding, no blank
sample. direct reading of BOD value. continuous display of BOD
value at the current incubation time.
In this experiments, BOD5 will be examined by dilution method
(Standard Method 5210B)
Dilution method
To ensure that all other conditions are equal, a very small
amount of micro-organism seed is
added to each sample being tested. This seed is typically
generated by
diluting organismswith buffered dilution water. The BOD test is
carried out by diluting the
sample with oxygen saturated dilution water, inoculating it with
a fixed aliquot of seed,
measuring the dissolved oxygen (DO) and then sealing the sample
to prevent further oxygen
dissolving in. The sample is kept at 20 C in the dark to prevent
photosynthesis (and thereby the
addition of oxygen) for five days, and the dissolved oxygen is
measured again. The difference
between the final DO and initial DO is the BOD.
The loss of dissolved oxygen in the sample, once corrections
have been made for the degree of
dilution, is called the BOD5. For measurement of carbonaceous
BOD (cBOD), a nitrification
inhibitor is added after the dilution water has been added to
the sample. The inhibitor hinders
the oxidation of ammonia nitrogen.
BOD can be calculated by:
http://en.wikipedia.org/wiki/Organismshttp://en.wikipedia.org/w/index.php?title=Buffered_dilution_water&action=edit&redlink=1http://en.wikipedia.org/wiki/Oxygenation_(environmental)http://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Oxygenation_(environmental)http://en.wikipedia.org/w/index.php?title=Buffered_dilution_water&action=edit&redlink=1http://en.wikipedia.org/wiki/Organisms
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Undiluted: Initial DO - Final DO = BOD Diluted: ((Initial DO -
Final DO)- BOD of Seed) x Dilution FactorBOD is similar in function
to chemical oxygen demand (COD), in that both measure the
amount
oforganic compounds in water. However, COD is less specific,
since it measures everything that
can be chemically oxidized, rather than just levels of
biologically active organic matter.
http://en.wikipedia.org/wiki/Chemical_oxygen_demandhttp://en.wikipedia.org/wiki/Organic_compoundhttp://en.wikipedia.org/wiki/Organic_compoundhttp://en.wikipedia.org/wiki/Chemical_oxygen_demand
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3.0 LITERITURE REVIEW
3.0 The purpose of Biochemical Oxygen Demand (BOD) is to
determine the
concentration of oxidizable and biodegradable organic compound
in water. The
experiment most often runs for a five day period. Application of
BOD is in measuring
waste loading of treatment plants, and in evaluating the
efficiency of treatment processes.
Actually, BOD is an international regulatory environmental index
for monitoring organic
pollutants in wastewater and the current legislated standard
test/experiment for BOD
monitoring requires 5 days to complete (BOD5). The reason is of
the results of BOD5 in
the 5-day long are seldom of any use for real time process
adjustment or decision making
(Determination of Biochemical Oxygen Demand (BOD) in water,
n.d.).
3.1 Extent of Biochemical Oxygen Demand (BOD)
The BOD is also interpreted as measure of the concentration of
organic material that can
serve as substance to support the growth of microorganisms.
Means here, it refers to
quantity of oxygen required by bacteria and other microorganisms
in the biochemical
degradation and transformation of organic material under aerobic
conditions (Kumar and
Kumar, 2005a). According to Rastogi et al., (2003) the BOD5
test/experiment has
remained a standard pollution monitoring tool since 1936. The
conventional BOD test
requires a 5-day incubation period at 20 C and demand skill in
determination, thus make
it unsuitable for process control.
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Kumar and Kumar (2005b) stated that BOD test as used for
assessing the efficiency of
wastewater treatment is intended to measure some fraction of the
carbonaceous oxygen
demand. Delzer and McKenzie (2003a) purport that the decay of
organic matter in water
is measured as biochemical or chemical oxygen demand whereby
they defined oxygen
demand as a measure of the amount of oxidizable substances in a
water sample that can
lower dissolved oxygen (DO) concentrations (Nemerow, 1974;
Tchobanoglous and
Schroeder, 1985).
3.2 Other Study Related to BOD
Some studies have examined some phenomenon related to BOD such
as
Development and Characterization of a Novel Immobilize Microbial
Membrane for
Rapid Determination of Biochemical Oxygen Demand Load in
Industrial Waste-waters
by (Mehra et al., 2003). Decomposition in the BOD test comprise
of two stages which is
carbonaceous stage (first stage) and a nitrogenous stage (second
stage). The first stage
represents that portion of oxygen demand involved in the
conversion of organic carbon to
carbon dioxide while the second stage performed a combined
carbonaceous and
nitrogenous demand, when organic nitrogen, ammonia, and nitrite
are converted to nitrate
(Delzer and McKenzie, 2003b).
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4.0 OBJECTIVE
To determine the amount of organic pollutant in water and
wastewater
5.0 MATERIALS & METHODOLOGY
Equipment:
i. Incubation bottles: 300 mL bottles
ii. BOD incubator
iii. Volumetric flask, 1L.
iv. Beaker, 500mL.
v. Dissolved oxygen meter.
Chemical Use:
i. Phosphate buffer solution
ii. Magnesium sulfate solution
iii. Calcium chloride solution
iv. Ferric chloride solution
v. Acid and alkali solutions
vi. Industrial Waste
vii. Distilled Water
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Methodology:
a) Preparation of dilution water: Each 1mL of phosphate buffer,
magnesium sulfate, calcium
chloride, ferric chloride solution was added into 1L volumetric
flask then adds distilled water to
1L.
b) Preparation of Sample: Take 10mL wastewater sample and add
into a 500mL beaker. Then,
add dilution water up to 300mL into the same beaker. Next,
adjust pH value to 6.5 to 7.5 by
adding acid/alkali solution.
c) Preparation of control (blank): Take 300mL dilution water as
control and put into another
500mL beaker.
d) Experimental methodology:
i. All prepared samples and control were put into
300mL-incubation bottle each.
ii. Then, Dissolved oxygen (DO) concentrations for each sample
were measured using
Dissolved Oxygen Meter and the readings were recorded.
iii. After measured the BOD, we add water to the flared mouth of
bottle and cover them with
an aluminum foil.
iv. All the bottles then were put in BOD Incubator for five
days. The temperature was set at
20C.
v. After five days, we measure the final DO value.
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6.0 RESULTS & DISCUSSIONS
5.01 Results
DO1, mg/L DO2, mg/L BOD5, mg/L
Control 7.21 7.67 -13.8
Sample 7.19 0.56 198
pH value: 6.87
5.02 Discussion
Calculation for BOD5
Formula:
BOD5, mg/L = (D1D2) x Dilution factor
Dilution factor = Bottle volume (300mL) / Sample volume
Dilution Factor:
BOD5 for Sample:
( )
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BOD5 for Control:
( )
5.03 Questions
1. Discuss your results by comparing with Standard A or Standard
B as stated inEnvironmental Quality Act 1974.
Our experimental BOD5 value seems very high from EQA standard
for both standard A
and B; 198.9 rather than 20 and 50. This is because; the
industrial waste we get is from
very aggressive company activity, oil and Gas Company. Also, the
sample was keep for
too long before we use to evaluate the BOD content.
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2. What is the purpose of adding water to the flared mouth of
bottle? Why the flared mouthof bottle should be covered?
The reason why we should adding water to the flare mouth of
bottle is to avoid the air
from coming out and in from the sample bottle that can affect
our oxygen content. The
flared mouth of the bottle should be covered also to avoid the
water from evaporate once
we put into the BOD incubator.
3. Why the light must be excluding from air incubator?To avoid
the growth of algae from the industrial waste that will use the
oxygen left in
bottle.
4. Samples of BOD analysis may degrade significantly during
storage between collectionand analysis, resulting in low BOD
values. Suggest one step to minimize the reduction of
BOD.
Minimize reduction of BOD by analyzing the sample promptly or by
cooling it to near
freezing temperature during storage. However, even at low
temperature, keep holding
time to a minimum. Samples should be warmed before analysis.
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7.0 CONCLUSION & RECOMMENDATION
It can be concluded that the observations for each type of both
sample and control
dissolve oxygen (DO) concentration were different after been
left for five days. We also can say
that pollutants do have an effect on the level of oxygen in
water system. However, the readings
we observed from control showed differ result. The reading for
final DO concentration is higher
than the initial one. The final DO concentration should be lower
than the initial. This might cause
due to weak batteries for stirring unit result in inadequate
flow across. Or maybe the Deionized
water contains semi volatile organic compounds leached from the
resin bed.
To prevent these errors, we have to make sure that the batteries
for stirring unit should
always in a good condition. Then you also have to increase the
purity of dilution water or obtain
it from another source. Make sure you are using a clean and
in-good-condition apparatus so no
leakage occurred.
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8.0 REFERENCES
Delzer, G. C., & McKenzie S. W. (2003). Five-day biochemical
oxygen demand. Retrieved
October 3, 2011, from
http://74.6.117.48/search/srpcache?ei=UTF-
8&p=Determination+of+Biochemical+Oxygen+Demand+%28BOD5%29+In+Water+an
d+Wastewater&fr=mkg030&u=http://cc.bingj.com/cache.aspx?q=Determination+of+Bio
chemical+Oxygen+Demand+%28BOD5%29+In+Water+and+Wastewater&d=46981791
30820630&mkt=en-US&setlang=en-
US&w=e2eab9c2,ec2c0828&icp=1&.intl=us&sig=ptuh1aBQqW6m7uNNu_ohqQ--
Kumar, R,. & Kumar A. (2005). Water Analysis/Biochemical
oxygen demand.Biochemical
Oxygen Demand(pp. 5527-5533). Retrieved October 3, 2011,
from
http://www.sciencedirect.com.ezproxy.ump.edu.my/
Rastogi, S., Kumar, A., Mehra N. K., Makhijani, S D., Manoharan,
A., Gangal, V., et al. (2003).
Development and characterization of a novel immobilized
microbial membrane for rapid
determination of biochemical oxygen demand load in industrial
waste-water. Biosensors
and Bioelectronics. Retrieved October 3, 2011, from
http://www.sciencedirect.com.ezproxy.ump.edu.my/
http://www.sabah.gov.my/jpas/Assessment/eia/sp-eias/Benta/eia/AnnexB/AnnexB.pdf
http://www.norweco.com/html/lab/test_methods/5210bfpCBOD.htm
http://www.sciencedirect.com.ezproxy.ump.edu.my/http://www.sabah.gov.my/jpas/Assessment/eia/sp-eias/Benta/eia/AnnexB/AnnexB.pdfhttp://www.norweco.com/html/lab/test_methods/5210bfpCBOD.htmhttp://www.norweco.com/html/lab/test_methods/5210bfpCBOD.htmhttp://www.sabah.gov.my/jpas/Assessment/eia/sp-eias/Benta/eia/AnnexB/AnnexB.pdfhttp://www.sciencedirect.com.ezproxy.ump.edu.my/
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9.0 APPENDICES
