Jerry JACK
2130259.6
BECV/3
DR. REVANURU
SUBRAMANYAM
Jerry
JACK
Department of Civil Engineering
10/10/2022
CONTENT
EXPERIMENT 1: INTRODUCTORY LAB............................................................................................2
INTRODUCTION ................................................................................................................ ........2
AIM...............................................................................................................................................2
LAYOUT & EQUIPMENT: ........................................................................................................2
DISCUSSION................................................................................................................... ............2-6
CONCLUSION.............................................................................................................................6
EXPERIMENT 2: TOTAL SOLIDS .................................................................................................. .....7
INTRODUCTION: .......................................................................................................................7
AIM:......................................................................................................................... .....................7
PRINCIPLE: .................................................................................................................. ...............7
METHODOLOGY: ......................................................................................................................8
CALCULATIONS................................................................................................................. ........8
RESULTS .....................................................................................................................................8
CONCLUSIONS: ................................................................................................................ .........8
EXPERIMENT 3: TOTAL SUSPENDED SOLIDS...............................................................................9
INTRODUCTION:................................................................................................................ .......9
AIM:.............................................................................................................................................9
PRINCIPLE: .................................................................................................................. ..............9
APPARATUS: .............................................................................................................................9
PROCEDURE:................................................................................................................... .........10
RESULT ...................................................................................................................... ...............10
DISCUSSION:.............................................................................................................................10
CONCLUSION:...........................................................................................................................10
EXPERIMENT 4: TOTAL DISSOLVED SOLIDS ..............................................................................11
INTRODUCTION: ............................................................................................................... ........11
AIM:..............................................................................................................................................11
PRINCIPLE: .................................................................................................................. ...............11
APPARATUS: ..............................................................................................................................11
PROCEDURE:................................................................................................................... ............11
SAMPLE CALCULATIONS: ......................................................................................................12
RESULTS ..................................................................................................................... ................12
DISCUSSION:.................................................................................................................. .............12
CONCLUSIONS: ..........................................................................................................................12
EXPERIMENT 5(a): pH TEST................................................................................................................. 14
INTRODUCTION: ............................................................................................................... .........14
AIM:............................................................................................................... ................................ 14
APPARATUS: .................................................................................................................. ............ 14
PROCEDURE:................................................................................................................... ........... 15-16
RESULTS AND CONCLUSIONS:...............................................................................................16
EXPERIMENT 5(b): TURBIDITY TEST……………………............................................................ 17
INTRODUCTION: ............................................................................................................... ...... 17
AIM:......................................................................................................................... .................... 17
APPARATUS: ...............................................................................................................................17-18
PROCEDURE:................................................................................................................... ............ 18
RESULTS AND CONCLUSIONS:................................................................................................ 18
EXPERMENT 6: JAR TEST……………………………………………………………………………..19
INTRODUCTION: ............................................................................................................... .........19
AIM:................................................................................................................................................19
APPARATUS: .............................................................................................................................. 19
PROCEDURE:................................................................................................................... ........... 20
RESULTS AND CONCLUSIONS:............................................................................................. 20
REFERENCES .................................................................................................................. .................... 21
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Experiment 1: INTRODUCTORY EXPERIMENT
Introduction.
Environmental Engineering is a profession which is directly involved with the identification and design solutions for
environmental problems and this lab is the introductory to the equipment and the layout of the lab. Environmental
Engineering mainly deals with the study and solution for environmental problems and certain special equipment’s are
used for testing and storing samples that are brought in.
Aim
The purpose of the first introductory lab was for the understanding of the equipment and the better understanding of
the layout of the Environmental Lab.
Layout and Equipment
The layout is a simple diagrammatic representation of the location of the equipment’s as to the position it is located
inside the environmental lab. The equipment is assigned with numbers as shown on the map provided below.
List of Names of the lab equipment and Testing Apparatus
1. Fume Cabinet
2. Hot water Bath
3. BOD Incubator
4. Turbidity Meter
5. PH/Conductivity meter
6. Filtering Apparatus
7. Balance
8. Suction Pump
9. Bacteria Tester
10. Oven
11. Oven
12. Refrigerator
13. Jug & Glass Bottles
14. Beaker & Funnels
15. Testing Tubes & Stands
16. Centrifugal
17. High Performance Liquid Chromatography
18. Sterilizer
19. Atomic Absorption Spectrometer
20. Spectrometer
21. Bacterial Indicator
Discussion:
The equipment listed below are the equipment that are provided by the Civil Engineering Department of Papua New
Guinea of Technology for the use and study of Environmental Engineering.
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1)Fume Cabinet
A fume cabinet is a type of local
ventilation device that is designed to limit
exposures to hazardous or toxic fumes,
vapors or dust. It is typically a large piece
of equipment which encloses five sides of
a work area, the bottom of which is most
commonly located at a standing work
height. The fume cabinet is used to:
•
Protect the user from inhaling toxic
gases.
•
Protect the product or experiment.
•
Protect the environment.
2) Water Bath
A water bath is basically a container filled
with heated. It is used to incubate samples
in water at a constant temperature over a
long period of time. Utilizations include
warming of reagents, melting of substrates
or incubation of cell cultures. It is also
used to enable certain chemical reactions
to occur at high temperatures.
3) BOD Incubator
An incubator is a device used to grow and
maintain microbiological cultures or cell
cultures. The incubator maintains optimal
temperature, humidity and other conditions
such as CO2 and oxygen content of the
atmosphere inside.
4) Turbidity Meter
It is used to quickly measure the turbidity
(Cloudiness) of water, caused suspended
solid particles. High turbidity values
means it’s very dirty and is unsafe for use
(drink) while low turbidity reading means
water is less polluted.
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14)Spectrophotometer
15) Bacterial
Incubator
The spectrophotometer
measures the intensity of
electromagnetic energy at
each wavelength of light in a
specified region.
This incubator is used for the
incubation of mainly bacteria.
CONCLUSION:
The discipline of environmental engineering involves the extensive knowledge of the chemistry and
biology of potential contaminants as well as industrial or agricultural processes. As part of the discipline it
is necessary to carry out tests and experiments in the laboratory. Therefore, a basic knowledge and
understanding, and handling of the equipment is vital towards the approach of the discipline.
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Experiment 2: TOTAL SOLIDS
Introduction.
Total solids (TS), is a measure of all the suspended, colloidal, and dissolved
solids in a sample of water. Furthermore, Total Solids are the solids that remain as residue after evaporation and
drying of the unfiltered sample. This includes dissolved salts such as sodium chloride, and solid particles such as silt
and plankton. An excess of total solids in rivers and streams is a very common problem.
An
Environmental Engineer can carry out Total Solids measurements as a useful indicator for effects of runoff from
construction, agricultural practices, logging activities, sewage treatment plant discharges and other sources. It can
also be carried out to determine and check streams and rivers whether it’s okay for human consumption and usage or
not.
Aim
The purpose of the Total Solids Experiment was to determine the residue left after evaporation and drying of the
unfiltered sample.
METHODOLOGY
APPARATUS
The apparatus used for this lab test are in;
1.
2.
3.
4.
5.
6.
Evaporating Dishes (Pyrex, Crucibles, porcelain or platinum)
Oven
Desiccators
Water Bath
Measuring Cylinder
Balance
PROCEDURE
The procedure that are used in this laboratory experiment are as follows;
1. The porcelain dish was washed and dried in the oven for some time before it was placed in the desiccator
to cool off before it was weighed (W1)
2. A sample of 25 ml of well mixed sample (graduated cylinder was rinsed to ensure transfer of all
suspended matter) measured using the measuring cylinder was placed in a dish and later was evaporated
at 1000C on the water bath, the sample was later dried in oven at 1030C for 1 hour.
3. The sample was taken out the oven and placed in the desiccator to cool off before the final weight (W2)
reading was recorded.
SIGNIFICANCE:
1. Total solids determination is used to assess the suitability of potential supply of water for various uses.
2. The pH at stabilization depends on total solids also.
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RESULTS
The total solid was recorded in concentration, that is in milligrams per liter. The measured results are shown
in Table 1. The volume of the empty crucibles was recorded as 50 milliliters. The weight of the residues was
measured by taking away the final weight of the dish from the initial weight of the dish.
Table 1. Experimental data of total solids for the given water samples.
Sample
Number
Sample
details
1
2
Volume of
sample (V)
(ml)
50
50
Initial
weight of
the dish
(W1) (mg)
52.96
56.30
Final weight
of the dish
(W2) (mg)
Weight of
residue (W)
(mg)
Total solids
(mg/l)
57.469
57.478
4.509
1.179
90.18
23.56
CALCULATIONS:
Where:
W1 = Initial weight of the dish in mg
W2 = Final weight of the dish in mg
V = Volume of sample taken in ml
DISSCUSION:
The samples that were collected for testing total solids was from the UNITECH sewage pond and because the
system is maintained through phytoremediation, amount of solids present play a key role in maintaining the growth
of the plants and micro-organisms to reduce the contaminants that are found in the sewage pond.
Through the observations of the results, it can be deduced that sludge samples all contained uniform amount of
solids from the different locations that they were collected from. The slight difference in mass of the total solids
came as a result of being kept in the heating oven for 24 hours.
SUMMARY
In conclusion, the testing of Total solids helps students to understand the importance of determining total solids for a
sludge sample from the sewage pond and know the associated effects the pond may face due to insufficient solids in
the sewage ponds.
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Experiment 3: TOTAL SUSPENDED SOLIDS
Introduction.
Total suspended solids can be simply defined as the dry-weight of suspended particles that are not dissolved, in a
sample of water which can be trapped by a filtration apparatus and then analyzed. Therefore, total suspended solids
are determined by using the simple method of filtration.
In this experiment report, I have outlined and discussed the data results and made possible environmental
conclusions regarding the samples of the UNITECH sewage pond system.
Aim:
To determine the total suspended solids of Unitech Sewage Pond.
Principle:
Total suspended solids are determined as the residue left on a filter paper after drying in oven.
Significance:
1. Suspended solids may be objectionable in water for several reasons. It is aesthetically displeasing and
provides adsorption sites for chemical and biological agents.
2. Suspended organic solids which are degraded anaerobically may release obnoxious odors.
3. Biologically active (live) suspended solids may include disease causing organisms.
4. The suspended solids parameter is used to measure the quality of wastewater Influent and effluent and is
useful in the analysis of polluted water.
Apparatus
The equipment’s that were used in the experiment in finding the Total solids are;
1.
2.
3.
4.
5.
Filter paper
Desiccator
Balance
Measuring cylinder
Oven
Procedure:
The procedure used in caring out the experiment are as follows;
1. A clean filter paper was kept in the oven for some time, then later cooled in a desiccator and was weighed to
and (W1) was recorded.
2. Then filtrated 25 ml of well mixed sample through filter paper, which is kept on funnel.
3. Carefully removed the filter paper and oven dried in the at 1050C for one hour.
4. Later it was Cooled in a desiccator and finally weigh (W2) were recorded. Note that the steps were repeated
for three (3) separate Samples.
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Analysis and Results.
The total solid was recorded in concentration, that is in milligrams per liter. The measured results are shown in Table
1. The volume of the empty crucibles was recorded as 50 milliliters. The weight of the residues was measured by
taking away the final weight of the dish from the initial weight of the dish.
Table 2. Experimental data for total suspended solids for the given water samples.
Sample
Sample details
Volume of
Initial weight of the
Final weight of
Total
sample
filter paper
the filter paper
suspended
(V) (ml)
(W1) (mg)
(W2) (mg)
solids (mg/l)
1
50
1.033
1.143
2.2
2
50
1.022
1.146
2.48
Number
Calculations:
1. Mass Calculations
Total Mass of Solid (mg) = W2 – W1
Sample 1: 1.143 – 1.033 = 0.11 mg
Sample 2: 1.146 – 1.022 = 0.124 mg
2. Suspended Solid Calculation
Total suspended solids(mg/l) =
(W2 - W1) x 1000
----------------------V (ml of sample taken)
W1 =
Initial weight of filter paper in mg.
W2 = Final weight of filter paper in mg.
V = Volume of sample, ml
DISSCUSION
As can be seen from the results, the total solids calculated for each sample varies. This variation of concentration
is mainly due to the particle sizes and the amount of concentration in a particular sample. Sample with greater
particle size or great amount of particles present have greater concentration as shown above. For this experiment it
was assumed that moisture will not affect the dry mass of the filter paper but in reality moisture is definitely a factor
for the filter mass.
SUMMARY
To conclude, the objective of this experiment has been achieved. The total suspended solids of all the sample is
calculated. By doing this experiment we can determine the type of solids present to see whether it is harmful to
human and other living things or not. Also by furthering the experiment using other methods, we can find the type
of substance and organisms present from the dissolved solids which passes through the filter paper. However, for
this experiment we have successfully achieved our aim.
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Experiment (4) - Total Dissolved Solids
Introduction.
Total dissolved solids (TDS) is defined as all inorganic and organic substances contained in water that can pass
through a 2-micron filter. In general, TDS is the sum of the cations and anions in water. Ions and ionic compounds
making up TDS usually include carbonate, bicarbonate, chloride, fluoride, sulfate, phosphate, nitrate, calcium,
magnesium, sodium, and potassium, but any ion that is present will contribute to the total
Determination of Total Dissolved Solids is very important and useful. Civil Engineers in the field of
Environmental Engineering carry out this lab test to determine whether the water is suitable for consumption
(drinking), agricultural, industrial and even to find out disease causing organisms and substances. Suspended
material is aesthetically displeasing and provides absorption sites for chemical and biological agents. Therefore, in
this experiment we are going to compare and find out Total Dissolved Solids in samples of Sewage Pond and
Distilled water
Aim:
The purpose of the experiment was to determine the total dissolved solids of the given water samples.
Principle:
Total dissolved solids are determined as the residue left after evaporation and drying of the filtered sample.
SIGNIFICANCE:
1. Many dissolved substances are undesirable in water. Dissolved minerals, gases and organic constituents may
produce aesthetically displeasing color, taste and odor.
2. Estimation of total dissolved solids is useful to determine whether the water is suitable for drinking purposes,
agriculture and industrial processes or not.
3. High concentration of dissolved solids about 3000 mg/I may also produce distress in livestock. In industries, the
use of water with high amount to dissolved solids may lead to scaling in boilers, corrosion and degraded quality of
the product.
4. Water with higher solids content often has a laxative effect.
5. Refer to experiment on electrical conductivity (EC) also.
Apparatus
The following materials were used in conducting this experiment:
1)
2)
3)
4)
5)
Evaporating dishes (Pyrex, porcelain or platinum)
Oven
Desiccators
Water bath
filter paper No. 44
Procedures
The following procedure was used in performing this experiment.
1. A clean porcelain dish was dried in an oven, cooled in a desiccator and then weighed. This weight was recorded
as W1.
2. A 25mL of filtered sample was placed in the dish and evaporated at 100°C on a water bath/oven.
3. The sample was dried to a constant weight in the oven at 103°C for one hour. It was then cooled in a desiccator
and weighed. This weight was recorded as W2.
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Results
Table 1: Observation Table
Sample No.
Sample
details
Volume of
sample (mL)
1
2
SEWAGE
WATER
25
25
Initial weight
of the dish
W1 (g)
50.975
57.531
AVERAGE
Final weight
of the dish
W2 (g)
Total
dissolved
solids (mg/L)
50.980
57.538
200
280
240
Calculations
Total dissolved solids (mg/l) = [(W2 – W1) x 1000] / V
where:
W1 = initial weight of dish in mg; W2 = final
weight of dish in mg;
V = volume of sample taken in ml.
1. Sample No.1
TDS = [(50.980 – 50.975) g x 1000mg/g] / 0.025L = 200
mg/L
2. Sample No.2
TDS = [(57.538 – 57.531) g x 1000mg/g] / 0.025L
= 280 mg/L
Discussion:
For the results above, it can be seen that sample 1 of distilled water has a significant value of TDS, this simply
indicates some errors occurred while handling of the sample. The negative TDS value of sample 2 is the result of
errors involving the weighing of the sample, either from the initial or the final weight. For sample 3 and 4 (sewage
pond), the TDS values of the samples are reasonable as it has significant value of TDS as shown which may consist
of different physical, chemical and biological matter.
Conclusion:
To conclude, the total dissolve solids of the four given samples have been calculated and determined. This
indicates that the aim or the objectives of this lab experiment has been achieved. Further lab tests can be done in
determining the type of substances (organic or in – organic) present in the samples. This will then have helped in
providing the suitable water treatment method for the treating the water, either for consumption or other uses.
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Experiment 5 (a): pH TEST
Introduction:
The pH test was the first part of the fifth and Final experiment, the test was done on different samples by
colorimetric method and also the electrometric methods. The pH test or the ‘Power of Hydrogen test’ is a test that
will determine the pH of different samples. One important property of aquos solution is it concentration of Hydrogen
ion, The H+ ion has great effect on the solubility of many compunds and on the rates of chemical reaction. It is
important of different pH levels which are from 1-14, the levels 1-7 are conceded as alkaline solution and from 8-14
are basic solutions.
Aim: To determine pH of the given water samples.
Theory:
pH value denotes hydrogen ion concentration in the liquid and it is the measure of acidity or alkalinity of the liquid.
According to the law of mass action, in any liquid
Conc. of H ions × Conc. of OH ions/ Conc. of un-dissolved HOH molecules
constant = 10-14
For convenience pH scale is taken from 0 to 14.
Principle:
pH of a liquid sample can be determined either by:
(i)
Coloumetric method or use of indicators
(ii)
Electrometric method
Electrometric method of pH determination:
It is determined through an instrument by electrolysis and dissociation of H+ and OH- radical, and the milivolts
generated give on scale either by movement of analog pointer or digital recording. Knowing pH value is a very
important parameter for the analysis of wastewater and its treatment. Certain chemicals and biological processes work
only at a particular pH.
Apparatus:
The equipment’s that are used in the experiment.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Wide range pH indicator strip
Narrow range pH indicator strip
Portable electronic pH meter tester
100mL sample of tap water
50mL diluted sulphuric acid (0.02mol) (H2SO4)
25mL concentrated sulphuric acid (H2SO4)
Stirring rod
Three 100mL beakers
Clamp and stand
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Reagents:
1) Distilled water
2) Standard buffer solutions: Standard buffer solutions having pH values of 4.0 and 9.2 are readily available.
Otherwise, they can be prepared easily by dissolving 1 pH tablet of each buffer in distilled water and make up
to 100 ml gives a standard solution of pH 4.0 and 9.2.
Procedure:
The pH of water can be found in the following manner.
1.
Using pH-paper:
(i) pH-strip (paper) was dipped into a wide-range (0-14) solution whose pH is to be found. The color of the
litmus paper had changed to thick red for highly acidic waters to dark green for highly alkaline waters and to any
other color depending on the pH of the solution. The colors were Compared the color of paper with the standard
colors supplied. The pH was noted with their corresponding number and matching colors.
(ii) The suitable narrow-range of the pH-strip was selected and the colors were compered using the same method
with wide-range pH strips. The pH was noted and the colors was compared with standard colors.
2.
(i)
(ii)
(iii)
Using pH-meter:
We Switched on the pH meter for 15 minutes.
The pH electrode was cleaned and the temperature probe were dipped into the solution and the readings
were noted
The CAL knob set the pH value to 4.0
(iv)
With a pH 9.2 buffer, set the pH value to 9.2 using the SLOPE knob.
(v)
The steps 2-3 were repeated till the pH meter is standardized with respect to both pH 4.0 and 9.2 (vi) The
pH values of the different water samples with the pH meter were recorded.
SIGNIFICANCE:
1.
Knowing pH value is very important parameter for analysis of water/wastewater and its treatment,
its suitability for domestic use and for irrigation. Certain chemical and biological processes work only at a
particular pH.of 6.5 to 8.5 has no direct adverse effect on health. However a lower value below will
produce sour taste and higher value above 8.5 a bitter taste. Higher value of pH encourages the scale
formation in water heating systems and also reduces the germicidal potential of chlorine. High pH induces
the formation of tri-halo-methane’s which are causing cancer in human beings. According to BIS, water
for domestic consumption should have a pH between 6.5- 8.5.
2.
Corrosion of water mains is the main the main problem associated with acidic waters.
Acidic/alkaline waters cannot be used for construction purposes also. If pH is less, algae die, fish cannot
reproduce and it causes acidity, corrosion, irritation of mucous membranes, tuberculosis and other health
problems in humans.
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Observation Table:
The following table displays the results of the pH values of the water samples tested.
Table 3. pH Values of Tap Water and Distilled Water Samples.
Sample
Description of sample
pH value
Number
pH paper
Wide
range
Narrow
range
pH
meter
1
Tap Water
7
6.5
7.80
2
Distilled Water
7
6.5
8.80
Discussion:
The lab performed for the three different samples and we had found out that
1) For the first sample (100mlL) as water sample Using the wide range pH strip we tested for its pH value. The
wide range test strip turned into a yellow color indicating a pH value of approximately 7.
2) The test was again performed by the narrow range pH strip. The yellow strip from weak yellow turned into a
strong yellow. This indicated a pH value varying from 6-8. The final test carried was using the portable pH testing
machine. The sample when tested indicated a precise pH value of 7.80.
3) The second test which was 100ml of distilled water tested using the wide range strip for its pH value. The wide
range test strip turned into a yellow color indicating a pH value of approximately 7. This indicated a pH value varying
from 6-9. The final test carried was using the portable pH testing machine. The sample when tested indicated a
precise pH value of 8.80.
Of these two samples, the one that shows the least spread of pH values between the three various pH test methods
is the tap water. This is indicated by the pH being close to neutrality (pH = 7) for all two tests.
Conclusions:
To conclude the experiment is best suited for the study of chemicals that are present in the environment. The pH
test is one of the important that will be carried out by Chemical and Environmental Engineers as it predicts the type
of environment and chemical components. This experiment was performed and conducted and we clearly can now
test the pH of any sample using one of the three methods
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Experiment 5 (b): TURBIDITY TEST
Introduction:
This experiment the Turbidity Test was carried out conducted as means for us to better understand the
importance of the turbidity.
Aim: To find out Turbidity of the given sample.
Principle:
When light is passed through a sample having suspended particles some of the light is scattered by the particles. The
scattering of the light is generally proportional to the turbidity. The turbidity of sample is thus measured from the
amount of light scattered by the sample taking a reference with standard turbidity suspension.
Apparatus
The equipment that were used;
1. Nephelometric Turbidity meter
2. Sample tubes
Reagents:
1. Dissolve 1 g of Hydrazine sulphate and dilute to 100 ml
2. Dissolve 10 g Hexamethylene Tetra amine and dilute to 100 ml
3. Mix 5 ml of each of the above solution (1 and 2) in a 100 ml volumetric flask and allow standing for 24 hours
at 25 ± 3°C and diluting to 1000 ml. This solution has a turbidity of 40 NTU.
4. This solution can be kept for about a month.
Procedure:
The procedure that were implanted during the experiment;
1. The Nephelometric turbidity meter was switched on and few minutes later it warmed up.
2. The instrument was set at 100 on the scale with a 40 NTU standard suspension.
3. The sample was shaken thoroughly and after sometime all the air bubbles were eliminated.
4. The sample was taken Nephelometer sample tube and later placed in the chamber and the values on the scale
were noted.
5. The sample was later diluted with turbidity free water
Environmental significance:
1. Turbidity is objectionable because of aesthetic and engineering considerations. The colloidal material exerts
turbidity provides adsorption sites for chemical that may be harmful. In natural waters, turbidity may impart a
brown or other color to water and be harmful. In natural waters, turbidity may impart a brown or other color
to water and may interfere with light penetration and photosynthetic reaction in streams and lakes.
2. Slow sand filters cannot function if raw water has excess turbidity. A rapid sand filter may go out of function,
if excess turbidity exists.
3. Knowing about turbidity variation in raw water supplies is useful to determine whether a supply requires
special treatment by chemical coagulation and filtration before it may be used for a public water supply or not.
4. Turbidity measurement is used to find the efficiency of the treatment produced with different chemicals and
the dosages needed.
5. Turbidity measurement helps to gauge the amount of chemicals needed from day to day in the treatment
processes.
6. Turbidity measurements of the filtered water are needed to check the faulty filter operation.
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7. Measurement of turbidity in settled water prior to filtration is useful in controlling chemical dosages so as to
prevent excessive loading of repaid sand filters.
8. Often treated municipal waters also are found to contain excess turbidity. This may be due to adding
bleaching powder containing lot of impurities like clay or vacuum prevailing in the water mains during the
non-supply hours that may suck the stagnated (polluted) surface waters. As turbidity acts as a shield to protect
the microorganisms, bacterial population is found to be more in turbid water.
Results
Observation Table:
Turbidity Test Results
Sample
Sample details
Turbidity (NTU)
Number
1
Tap Water
14
2
Distilled Water
8.5
Discussion:
The test was carried out well and the observations made were as expected. The first sample tested sample A (Tap
water), a turbidity reading of 14NTU. This is the highest turbidity reading meaning that this solution is the
cloudiest and has the most dissolved and suspended particulate matter.
The second solution tested sample B tap water, gave a turbidity reading of 14NTU on the turbidity meter. This is
the second highest reading. Following was test solution (2) Distilled water, giving a turbidity reading of 8.5. Tap
water is treated with chemicals to eliminate bacteria so has some dissolved particles and chemicals.
Conclusions:
To conclude, the turbidity test is an essential test as it clearly defines the state of any water solutions. The of
importance turbidity can be seen in aquatic cultures as it determines the rate of photosynthesis which are the
building blocks for any food chain. In the experiment we learnt ways to perform and correctly interpret the data’s
and tried in making sense of the results.
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Experiment 6. JAR TEST
Introduction:
The jar test is a method of measuring the effect of coagulation, flocculation, and sedimentation on turbidity. Although
the procedure is not outlined in Standard Method, it is used in most water treatment plants to find the best coagulant
dosages under varying conditions.
Coagulation or flocculation is the process of binding small particles in the water together into larger, heavier clumps
which settle out relatively quickly. The larger particles are known as floc. Properly formed floc will settle out of water
quickly in the sedimentation basin, removing the majority of the water’s turbidity.
In this experiment, the jar test was performed on given water samples. By adding varying amounts of alum and
measuring pH values and turbidity, the optimum dosage of alum solution added to water sample shall be determined
by looking at trends in the data what the most effective approach to the water.
Aim:
The main aim of this experiment is to find the optimum amount of coagulant required to treat the turbid waters.
Principle:
Metal salts hydrolyse in presence of the natural alkalinity to form metal hydroxides. The divalent cations can reduce
the zeta potential, while the metal hydroxides are good absorbents and hence remove the suspended particles by
enmeshing them.
Apparatus:
The apparatus used for the experiment include:
1. Jar test apparatus
2. Turbidity meter
3. pH meter
4. Beakers, Pipettes
Reagents:
1. 1% Alum solution (dissolve 1.0 gram of alum in 100 ml distilled water).
Procedure:
1. 1 Liter of sample was taken into each of the four beakers.
2. The pH of the sample was found and adjusted to 6 to 8.5.
3. Switch on the motor was switched and its speed of the paddles was adjusted to 100 rpm.
4. Varying doses of alum solution i.e., 0 ml, 1 ml, 2 ml, 3ml, 4ml, or 6 ml was simultaneously added to different
beakers (the doses varied with turbidity in water sample).
5. A flash mix was allowed (at 100 rpm) for 1 minute.
6. The speed of paddles was reduced to 40 rpm and the mixing was continued for 10 minutes.
7. The motor was switched off and it was allowed 20 minutes to settle.
8. The supernatant was collected without disturbing the sediment and the turbidity of each was found.
9. The graph between Turbidity on Y- axis and alum dosage on X-axis was drawn.
10. The ideal (optimum) dose of the coagulant from graph (showing least turbidity) was noted for excellent flock
formation.
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Significance:
1. The test is useful for identification of natural coagulants like Nirmala seeds etc.
2. It is useful to estimate optimum dosage of coagulant required for raw waters and waste waters.
3. If excess alum (aluminium sulphate) is used as a coagulant in water treatment plants, aluminium may enter the
municipal water and thus the human body. Excess aluminium, if present in drinking water is highly toxic and
causes acute abdominal pain and ‘dementia’. On the other hand, if alum dosage is small, turbidity removal
may not be satisfactory.
Observation and calculations:
1. Raw water turbidity (NTU) = ……………………………
Table 4. Raw Turbidity and pH values for each Jar.
Sample
Number
Sample details/
jar no
1
2
3
4
Dosage of
Alum solution
(ml)
0
1
2
3
Dosage of
coagulant
(mg/l)
Results and discussion:
Ideal dose of coagulant (mg/l) =
The following graph shows the optimum dosage of alum solution.
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Residual turbidity
(NTU)
pH
32
9
61
9
6.9
7.46
7.50
7.40
As based on the data and observation, the samples indicate poor coagulation. Properly coagulated water contains floc
particles that are formed and dense, with the liquid between the particles clear. The turbidity tests of the water in each
beaker by using turbidimeter gives the result that samples 1 and 3 are more turbid whereas samples 2 and 4 are least
turbid and it is correspondent with the optimal coagulant dosage that is being used.
Conclusion and Recommendation
After analysing the data, the optimum dosage of water is found to be approximately 0.8 mL of alum. This conclusion
was reached based on the fact that the turbidity is at a minimum at this point, at 9 NTU.
The recommendation is based how the jar test is performed here. The alum will make the water acidic, and for this
reason buffer should be added at the same time, and in the same amount as the alum to stabilize the acidity of the
water.
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REFERENCES
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2. 3knolls. (2020, December). Wikipedia. Retrieved from Wikipedia Website: https://en
3. Allen, D., Cooksey, C., & Tsai, B. (2013). Spectrophotometry. Geneva: NIST.
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5. General Water Baths. (n.d.). Retrieved from Labwit: http://www.labwit.com
6. Harmes, B., & Payne, C. (2008). Biomass and Total Dissolved. Colorado: National Renewable Energy Laboratory.
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11. Scientific, G. T. (2021, May 17). Measuring Suspended Solids. Retrieved from Tools.thermofisher.com:
https://tools.thermofisher.com/content/sfs/brochures/Measuring-Suspended-Solids-AppNoteANSSONLINEEN.pdf
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