1. P.S.V. COLLEGE OF ENGINEERING
AND TECHNOLOGY
KRISHNAGIRI
CE8512- WATER & WASTE WATER
ANALYSIS
LABORATORY MANUAL
DEPARTMENT OF CIVIL ENGINEERING
( Regulation 2017)
PREPARED BY
S.LOKESH M.E, (Ph.D).,
ASST.PROFESSOR/CIVIL
VERIFIED BY
Dr.M.P.SENTHIL KUMAR M.E, Ph.D.,
HOD/CIVIL
2. LIST OF EXPERIMENTS
S.No Date Name of the experiments SIGINATURE MARK
1.a
Determination of pH
1.b
Determination of Turbidity
1.c
Determination of conductivity
2
Determination of Hardness
3.a
Determination of Alkalinity
3.b
Determination of Acidity
4
Determination of Chlorides
5.a
Determination of Phosphates
5.b
Determination of Sulphates
6
Determination of iron and fluoride
7
Determination of Optimum Coagulant
dosage
8
Determination of residual chlorine and
available chlorine in bleaching powder
9 Determination of Oil, and Grease
10
Determination of suspended, settleable,
volatile and fixed solids
3. 11
Determination Dissolved Oxygen and BOD
for the given sample
12
Determination of COD for given sample
13
Determination of SVI of Biological sludge
and microscopic examination
14
Determination of MPN index of given water
sample
4. EX.NO : 1. a
Determination of pH in waterDATE:
Aim
TodeterminethepHofgivensamplesusingpH meter.
Guideline:
According to Environment Conservation Rules (1997), drinking water standard for pH
ranges from 6.5 to 8.5.
Principle:
pHvalueofwaterindicatesthehydrogenionconcentrationinwaterandconceptofpHwasputforward
bySorenson(1909).pHisexpressedasthelogarithmofthereciprocalofthehydrogenionconcentratio
ninmoles/litreatagiventemperature.ThepHscaleextendsfrom0(veryacidic)to14(veryalkaline)wit
h7correspondingtoexactneutralityat25°C.pHisusedinthecalculationofcarbonate,bicarbonateand
CO2,corrosionandstabilityindexetc.Whilethealkalinityoraciditymeasuresthetotalresistancetoth
epHchangeorbufferingcapacity,thepHgivesthehydrogenionactivityThepH electrode used in
the pH measurement is a combined glass electrode. It consists of sensing half-cell and
reference half-cell, together form an electrode system. The sensing half-cell is a thin pH
sensitive semi permeable membrane, separating two solutions, viz., the outer solution, the
sample to be analyzed and the internal solution enclosed inside the glass membrane and has a
known pH value. An electrical potential is developed inside and another electrical potential is
developed outside, the difference in the potential is measured and is given as the pH of the
sample.
Apparatus:
1. pH meter
2. Beaker
Reagent:
1. Buffers Solutions of known pH value
Procedure:
Perform calibration of the pH meter using standard pH solutions. The calibration
procedure would depend on the pH range of interest.
In a clean dry 100 mL beaker take the water sample and place it in a magnetic stirrer,
insert the teflon coated stirring bar and stir well.
Now place the electrode in the beaker containing the water sample and check for the
reading in the pH meter. Wait until you get a stable reading.
Take the electrode from the water sample, wash it with distilled water and then wipe
gently with soft tissue.
6. EX.NO : 1. b Determination of Turbidity of Water
DATE:
Aim
To determine the optimum dosage of Alum required for turbidity.
Guideline:
According to WHO standard 5 NTU is suggested as the turbidity limit for drinking water,
while 1 NTU is recommended to achieve the adequate disinfecting safety.
According to Environment Conservation Rules (1997), drinking Water standard for Turbidity
is 10 NTU (Nephelometric turbidity unit).
Principle:
Turbidity is based on the comparison of the intensity of light scattered by the sample under
defined conditions with the intensity of the light scattered by a standard reference suspension
under the same conditions. The turbidity of the sample is thus measured from the amount of
light scattered by the sample taking a reference with standard turbidity suspension. The
higher the intensity of scattered light the higher is the turbidity. Because of the wide variety
of materials that cause turbidity in natural waters, it has been necessary to use an arbitrary
standard. The original standard chosen was; 1 mg SiO2/L =1unit of turbidity. The silica
used had to meet certain specifications as to particle size. The standard nephelometry
procedure is now reported in nephelometric turbidity units (NTU). Because the basic
principles difference for Jackson candle turbidimeter method and nephelometric method,
results got from the two methods can vary widely. In order to avoid any confusion this may
cause, turbidity measurements by the standard nephelometry procedure are now reported in
nephelometric turbidity units (NTU), and the other one is reported in Jackson candle
turbidimeter units (JTU). 40 NTU are about equivalent to 40 JTU.
The applicable range of this method is 0-40 nephelometric turbidity units (NTU). Higher
values may be obtained with dilution of the sample.
Precautions:
The following precautions should be observed while performing the experiment:
The presence of coloured solutes causes measured turbidity values to be low.
Precipitation of dissolved constituents (for example, Fe) causes measured turbidity
values to be high.
Light absorbing materials such as activated carbon in significant concentrations can
cause low readings.
7. The presence of floating debris and coarse sediments which settle out rapidly will
give low readings. Finely divided air bubbles can cause high readings.
Apparatus:
1. Turbidity Meter
2. Beaker
3. Water sample
Chemicals
1. alum or ferric chloride
Procedure:Procedure
(1) Switch the instrument on.
(2) Open the lid of thesample compartment.
(3) Insertatesttubefilledwithdistilledwaterintothesamplecompartment.Closethelid.
(4) Adjust ‗SET 0‘ control to get ‗0‘ displayed on theread out.
(5) Openthelid.Replacethetesttubefilledwithdistilledwaterwithatesttubefilledwith
formazinestandard.Close thelid.
(6) Adjust the ‗SET 100‘control to get ‗100‘ displayed on the read out.(7) Repeat theabove operation to getconsistent values of 0 to 100 within 1%to 2%.(8)
Check for the reading in the turbidity meter. Wait until you get a stable reading.
Tabulation:
Sample
Source of Sample
Turbidity (NTU)
No
Result:
Turbidity of given sample …………………
8. Ex.No:1.c
Date: Determination of conductivity
Aim
To determine conductivity for strength of NaOH.
Introduction:
Conductivity is the capacity of water to carry an electrical current and varies both with number
and types of ions in the solutions, which in turn is related to the concentration of ionized
substances in the water. Most dissolved inorganic substances in water are in the ionized form and
hence contribute to conductance.
Principle
This method is used to measure the conductance generated by various ions in the
solution/water. Rough estimation of dissolved ionic contents of water sample can be made by
multiplying specific conductance (in mS/cm) by an empirical factor which may vary from 0.55 to
0.90 depending on the soluble components of water and on the temperature of measurement.
Conductivity measurement gives rapid and practical estimate of the variations in the dissolved
mineral contents of a water body.
Apparatus and equipment
a. Self-contained conductance instruments: (Conductivity meter). These are commercially
available.
b. Conductivity Cells: The cell choice will depend on the expected range of conductivity
and the resistance range of the instrument. Experimentally check the range of the instruments
assembly by comparing the instrumental results with the true conductance of the potassium
chloride solution.
Reagents and standards
Conductivity Water(NaOH): The conductivity of the water should be less than 1
m
mho/cm;
Standard potassium chloride: 0.N; dissolve 745.6mg anhydrous KCl in conductivity water and
make up to 1,000mL at 25°C. This is the standard reference solution, which at 25°C has a specific
conductance of 1,413
m
mhos/cm. It is satisfactory for most waters when using a cell with a
constant between 1 and 2. Store the solutions in glass stoppered Pyrex bottles.
Procedure
the burette is washed with distilled water and then rinsed with a little amount of the given
NaOHsolution.
Its then filled with NaOH solution upto the zero level.
20ml of the KCL is pipette out into a clean 100ml beaker
The conductivity cell is placed in it and then diluted to 50 ml by adding conductivity
water, so electrodes are well immersed in the solution.
Now 1ml of NaOH from the burette is added to the solution, taken in the beaker, stirred
Then conductivity is measured.
Plotted the graph by taking volume ofNaOH in X axis and conductance in the Y-axis.
The end point is noted from the graph
9. Calculation
Determination of strength of NaOH
Volume of KCL (V1) = 20ml
Strength of KCL (N1) =0.1 N
Volume of NaOH (V2) = --------------ml
Strength of NaOH (N2) = --------------N
V1N1= V2N2
N2=V1N1/ V2
Strength of NaOH (N2) = ---------------- N
Amount of NaOH present in 1000ml of the given solution
=Strength of NaOH X Equivalent weight of NaOH
= ------------------------- x 40
= -----------------gms
Model graph:
Result:
The conductivity of NaOH solution is ----------------------- N.
10. Ex.No:2
Date: Determination of Hardness
Aim
To determine the total hardness of thegivensamplesbyEDTA titrimetricmethod
Guideline:
According to WHO standard is suggested as the hardness limit for drinking water
Water Quality
Hardness
(mg/l as CaCO3)
Soft <50
Moderately hard 50-150
Hard 150-300
Very hard >300
Apparatus
1. Burette 2. Pipette 3. Erlenmeyerflask 4. Bottleetc.
Reagents
1. StandardEDTAtitrant (0.01 M)
2. Eriochrome black T indicator
3. Ammonia buffer solution
4. Water sample
Procedure
1. Dilute25mLofsample(V)toabout50mLwithdistilledwaterinanErlenmeyerflask.
2. Add 1 mLof buffer solution.
3. Add two drops of indicator solution. Thesolutionturns wine red in colour.
4. AddthestandardEDTAtitrantslowlywithcontinuousstirringuntilthelastreddishti
ngedisappearsfromthesolution.Thecolourofthesolutionattheendpointisblueund
ernormalconditions.
5. Note down the volume of EDTA added(V1).
12. Ex.No: 3 .a
Date: Determination of alkalinity
Aim
To determine the alkalinity of thegivensamples
Principle
Alkalinity of sample can be estimated by titrating with standard sulphuric acid (0.02N) at
room temperature using phenolphthalein and methyl orange indicator. Titration to decolourisation
of phenolphthalein indicator will indicate complete neutralization of OH
-
and ½ of CO3
--
, while
sharp change from yellow to orange of methyl orange indicator will indicate total alkalinity
(complete neutralisation of OH
-
, CO
3
--
, HCO
3
-
).
Apparatus
a. Beakers: The size and form will depend upon the electrode and the size of the sample
to be used for determination of alkalinity.
b. Pipettes (volumetric)
c. Flasks (volumetric): 1000mL, 200mL, 100mL
Reagents and standards
a. Standard H
2
SO
4
, 0.02 N: Prepare 0.1N H
2
SO
4
by diluting 3mL conc. H
2
SO
4
to 1000mL.
Standardise it against standard 0.1N Na
2
CO
3
solution. Dilute appropriate volume of H2SO4 to
1000mL to obtain standard 0.02 H
2
SO
b. Phenolphthalein indicator: Dissolved 0.5g in 500mL 95% ethyl alcohol. Add 500mL
distilled water. Add dropwise 0.02N NaOH till faint pink colour appears (pH 8.3).
c. Methyl orange indicator: Dissolve 0.5g and dilute to 1000mL with CO
2
free distilled
water (pH 4.3-4.5).
Procedure
a. Take 25 or 50mL sample in a conical flask and add 2-3 drops of phenolphthalein
indicator.
b. If pink colour develops titrate with 0.02N H
2
SO
4
till disappears or pH is 8.3. Note the
volume of H
2
SO
4
required.
c. Add 2-3 drops of methyl orange to the same flask, and continue titration till yellow
colour changes to orange. Note the volumes of H
2
SO
4
required.
d. In case pink colour does not appear after addition of phenolphthalein continue as
above.
13. Tabulation:
s.no Volume of water
sample
Volume of 0.02 N H
2
SO
4
phenolphthalein indicator[P] methyl orangeindicator [M]
ml ml ml
Calculations
Calculate total (T), phenolphthalein (P) alkalinity as follows:
P-alkalinity, as mg CaCO
3
/L = A x 1000/mL sample
T-alkalinity, as mg CaCO
3
/L = B x 1000/mL sample
In case H
2
SO
4
is not 0.02 N apply the following formula:
Alkalinity, as mg CaCO
3
/L = A/B x N x 50000 / mL of sample
N = normality of H
2
SO
4
Once, the phenolphthalein and total alkalinities are determined, three types of alkalinities, i.e.
hydroxide, carbonate and bicarbonate are easily calculated from the table given as under:
Type of alkalinity Values of P
and T
Type of Alkalinity
OH
-
CO
3
--
HCO
3
-
P = O 0 0 T
P<1/2T 0 2P T-2P
P = 1/2T 0 2P 0
P>1/2T 2P-T 2(T-P) 0
P = T T 0 0
If the data satisfies the condition P>1/2M
(i) Volume of H
2
SO
4
required for (OH-1
) alkalinity = 2P-T
= --------------- ml
(ii) Volume of H
2
SO
4
required for (CO3
2-
) alkalinity = 2(T-P)
= --------------- ml
(iii) (HCO3
-
) = 0
Result:
Hydroxide alkalinity = ----------------------- ppm
Carbonate alkalinity = ----------------------- ppm
Bicarbonate alkalinity = --------------------- ppm
14. Ex.No: 3.b
Date : Determination of Acidity
Aim
To determine the acidity of the givensamples
Principle
The acidity of water is its quantitative capacity to react with a strong base todesignated
pH or it can be defined as the base neutralizing capacity (BNC).In this article, we are going
to read about the determination of acidity of water.Strong mineral acids, weak acids such
as carbonic acids and acetic acid and hydrolyzing salt such as ferric and aluminium sulfates
may contribute to the sources of acidity in water.
Apparatus
1. Erlenmeyer flask
Reagents used in the acidity test of water
1. CO2 free distilled water
2. 0.02 N standard NaOH
3. Methyl orange indicator
4. Phenolphthalein indicator
5. Pipette
Procedure
1. Pipettes V mL (say 50 ml) of the sample to the flask.
2. Added 1 or 2 drops of methyl orange indicator.
3. The sample is then titrated against 0.02N standard NaOH. The endpoint is noted as colour
changed from orange-red to yellow. The titrate value is recorded as V1.
4. Added one or two drops of phenolphthalein indicator.
5. Titration is continued until the colour changed to faint pink. The volume of titrant used is
noted as V2.
15. Tabulation:
s.no Volume of water
sample
Volume of 0.02 NNaOH
phenolphthalein indicator[P] methyl orangeindicator [M]
ml ml ml
Calculation:
Result;
Total acidity in mg/l as CaCO3 -------------------
16. Ex.No: 4
Date: Determination of chlorides
Aim
To find theamount of chloridespresent in the givenwatersample.
Guide line:
Drinking water IS 10500 : 2012 Quality Standards for CHLORIDES is 1000 ppm
ApparatusRequired
1. Burette
2. Conicalflask
3. Measuringjar
Principle
Silvernitratereactwithchlorinetoformvery
slightlysolublewhiteprecipitateofAgclattheendpointwhenallthechloridesgetprecipitatefreesilver
ionsreactwithchromatetoformreddishbrowncolour
Reagents
1. Silvernitrate 0.01 N
2. Potassium chromate
Procedure
1. Take 20ml of thesamplein a conicalflaskandadd1-5 ml of K2CrO4solution.
2. Titrate the contents against 0.01N AgNO3untill ared tingecolourappears
3.
Tabulations
Burette solution
AgNO3Pipette solution
watersampleIndicator
K2cro4
End point Yellow to red colour.
17. S.NO
VOL OF
Nacl(V1
ml)
BURETTEREADING
(ml)
VOL OF
AgNO3
(V2 ml)
CONCORDANT
VALUE
(ml)
INDICATOR
Initial Final
1.
2.
Calculation
Chloride in mg/Lt = (ml ofAgNO3xNormalityofAgNO3x1000 x
Molecularweight of Chlorine)
--------------------------------------------------------------
Volume ofSample
Result
The amount of chloride present in the given sample is------------------
18. Ex.No: 5 a
Date: Determination of phosphates
AIM
Determination of phosphates by spectrophotometer.
Guide line:
Drinking water IS 10500 : 2012 Quality Standards for phophates is 0.1 ppm
PRINCIPLE
Phosphates in acidic condition reacts with ammonium molybdate to form
molybdophosphoric acid which is then reduced to molybdenum blue by adding stannous
chloride. The intensity of the blue colored complex is measured
spectrophotometrically,which is directly proportional to the concentration of phosphate
present in the sample.
APPARATUS
1. Spectrophotometer
2. Pipettes
3. Measuring cylinder
4. glass-rod
5. Beakers
6. Dropper.
REAGENTS
1.Ammoniummolybdate solution
In 175 ml of distilled water, add 25 g of ammonium molybdate. Now add 280 ml of
conc.sulphuric acid in 400 ml of distilled water and cool it. Make the volume upto 1 litres
with distilled water.
2. Stannous chloride solution
Dissolve 2.5 g of stannous chloride in 100 ml glycerol by heating in a water bath.
19. 3. Standard Phosphate Solution
Dissolve 4.388 g of anhydrous potassium hydrogen phosphate in 1000 ml distilled
water. Dilute this solution to 100 times (10ml-1000ml).This solution contains 10 mg P/l
(1ml = 0.01 mg P) which is used as standard phosphate solution.
PROCEDURE
1. Switch on the spectrophotometer and allow 20 minutes for warm up and set 410 nm
by adjusting the wavelength knob.
2. For calibration of the instrument take distilled water in the cuvette holder and place
in the compartment on the light path and close the compartment.
3. Press the mode button to set transmittance mode and set 100 % T.
4. Again press the mode button to set it for absorbance to read 0.00.
5. Fill the prepared standard solutions in the cuvette holders and place in the
compartment.
6. Read the colour developed on the display and note down the peak value.
7. Take 25 ml of filtered and clear sample.
8. Add 1 ml of ammonium molybdate solution and 2 drops of stannous chloride
9. Measure the blue color developed at 690 nm on a spectrophotometer using a
distilled water blank with the same chemicals.
10. Note down the readings of spectrophotometer after 5 minutes but before 12 minutes
of the addition of the last reagent.
11. Find out the concentration of the phosphate with the help of the standard curve.
21. Ex.No:5 b
Date: Determination of sulfates
AIM
Determination of sulfates by spectrophotometer.
Guide line:
Drinking water IS 10500 : 2012 Quality Standards for sulfates is 400 ppm
Principle
This method is used for the determination of sulphate ions. Sulphate ion (SO
4
--
) is
precipitated in an acetic acid medium with Barium chloride (BaCl
2
) so as to form Barium
sulphate (BaSO
4
) crystals of uniform size. The reaction involved is given below:
Ba
++
+ SO
4
—® BaSO
4
(White suspension)
Light absorbance of the BaSO
4
suspension is measured by a photometer or the scattering of
light by Nephelometer.
Apparatus and equipment
a. Magnetic stirrer
b. spectrometer for use at 420mm or turbidimeter/nephelometer
c. Stopwatch
d. Nessler tubes, 100mL
e. Measuring spoon 0.2 to 0.3mL
Reagents and standards
a. Buffer solution A: dissolve 30g Magnesium chloride, MgCl
2
.6H
2
O, 5g Sodium acetate
CH
3
COONa.3H
2
O, 1g Potassium nitrate, KNO
3
and 20mL acetic acid, CH
3
COOH (99%) in
500mL distilled water and make up to 1000mL.
b. Buffer solution B: (required when the sample sulphate (SO
4
--
) is less than 10mg/L).
Dissolve 30g Magnesium chloride, MgCl
2
.6H
2
O, 5g sodium acetate, CH
3
COONa.3H
2
O, 1.0g
of potassium nitrate, KNO
3
, 0.111 g of sodium sulphate, Na
2
SO
4
and 20mL acetic acid (99%)
in 500mL distilled water an make up to 1000mL.
c. Barium chloride: crystals, 20-30mesh.
d. Standard sulphate solution: dissolve 0.1479g anhydrous sodium sulphate, Na
2
SO
4
in
distilled water and dilute to 1000mL. 1L = 100 μg SO
4
--
This solution contains 100 mg
sulfate/L (i.e., 1 mL=100μg SO4 2-). Prepare standards of various strengths (preferably from
0.0 to 40.0mg/L at the intervals of 5 mg/L by diluting this stock solution). Above 40 mg/L
accuracy decreases and BaSO4 suspensions lose stability.
22. Procedure
a. Take suitable volume of sample and dilute to 100mL into a 250mL Erlenmeyer flask
b. Add 20mL buffer solution, mix well
c. Keep the flask constantly stirred with the help of stirrer. Add 1-spatula BaCl
2
crystals with
stirring. Continue stirring for 1 minute after addition of BaCl
2
d. Pour suspension into an absorption cell of photometer an measure turbidity at 5±0.5 min
e. To correct for sample colour and turbidity, run a blank to which BaCl
2
is not added.
f. Process the standard solution of different strengths in similar way and record the
absorbance for each solution.
g.Plot a standard sulfate calibration curve on a graph paper
from these absorbance values putting strengths (mg/L) on X-axis and absorbance @ 420
nm on Y-axis. Fit a best-fit linear model to the data.
Express equation as:
Absorbance value= A+B× Sulfate concentration (in mg/L)
Sulfate concentration (mg SO42-/L) = (1000×mg SO42-) / (mL sample)
Tabulation:
Sample name Absorbance
@420mm
Sample name Absorbance
@420mm
Distilled water blank Standard 1
Sample 1 Standard 2
Sample 2 Standard 3
RESULT
The amount of sulfate determined from the given sample is ________mg/l
23. Ex.NO:6
Date: Determination of iron &fluride
Aim
To determine the quantity of iron and fluoride present in the given sample of water.
Principle
Iron is usually present in natural water and is not objectionable, if concentration is less than
0.3 ppm. It may be in true solution in colloidal state that may be peptized by organic matter,
in the inorganic and organic iron complexes, or in relatively coarse suspended particles. It
may be either ferrous or ferric, suspended or filterable. Iron exists in soils and minerals
mainly as insoluble ferric oxide and iron sulphide (pyrite). It occurs in some areas, also as
ferrous carbonate (siderite), which is very slightly soluble.
The phenanthroline method is the preferred standard procedure for the
measurement of iron in water except when phosphate or heavy metal interferences are
present. The method depends upon the fact that 1, 10-phenanthroline combine with Fe++ to
form an orange-red complex. Its colour conforms to Beer‘s law and is readily measured by
visual or photometric comparison. Small concentration of iron can be most satisfactorily
determined by colorimetric analysis. It is also based on Beer‘s law. By measuring the
intensities of transmitted and incident light through a coloured solution and knowing its
optical density or transmission, we can prepare a calibration curve and subsequent
concentration can be read.
Apparatus required
1. Colorimetric equipment; one of the following is required
(a) Spectrophotometer, for use at 510 nm, providing a light path of 1 cm or longer.
(b) Nessler tubes, matched, 100 ml, tall form.
2. Glassware like conical flasks, pipettes and glass beads.
Reagents
1. Hydrochloric acid 2. Hydroxylamine solution
3. Ammonium acetate buffer solution
4. Sodium acetate solution
5. Phenanthroline solution 6. Stock iron solution
7. Standard iron solution (1 ml = 10 mg Fe)
Procedure
1. Pipette 10, 20, 30 and 50 mL. Standard iron solution into 100 mL conical flasks.
2. Add 1 mL hydroxylamine solution and 1 mL sodium acetate solution to each flask.
3. Dilute each to about 75 mL with distilled water.
4. Add 10 mL phenanthroline solution to each flask.
5. Make up the contents of each flask exactly to 100mL by adding distilled water and
24. left stand for 10 minutes.
6. Take 50 mL distilled water in another conical flask.
7. Repeat steps 2 to 5 described above.
8. Measure the absorbance of each solution in a spectrophotometer at 508 nm against
the reference blank prepared by treating distilled water as described in steps 6 and 7.
Prepare a calibration graph taking meter reading on y-axis and concentration of iron
on x-axis.
9. For visual comparison, pour the solution in 100 mL tall form Nessler tubes and keep
them in a stand.
10. Mix the sample thoroughly and measure 50 mL into a conical flask.
11. Add 2 mL conc. hydrochloric acid (HCl) and 1mL hydroxylamine solution. Add a
few glass beads and heat to boiling. To ensure dissolution of all the iron, continue
boiling until the volume is reduced to 15 to 20 mL.
12. Cool the flask to room temperature and transfer the solution to a 100 mL Nessler
tube.
13. Add 10 mL ammonium acetate buffer solution and 2 mL phenanthroline solution and
dilute to the 100 mL mark with distilled water.
17. Mix thoroughly and allow at least 10 to 15 minutes for maximum colour
development.
18. Measure the absorbance of the solution in a 1cm cell in a spectrophotometer at 508
nm.
19. Read off the conc. of iron (mg Fe) from the calibration graph for the corresponding
meter reading.
20. For visual comparison, match the colour of the sample with that of the standard
prepared in steps 1 to 7 above.
21. The matching colour standard will give the concentration of iron in the sample (μg
Fe).
25. Result
Iron content of the sample (mg/l) = --------------------
Fluoride content of the sample (mg/l) = ------------------
26. Ex.NO : 7
Date:
Determination of optimum Coagulant dosage
GENERAL
Chemical coagulation is an important process applied extensively in water treatment
practice, particularly, where surface supplies are involved chemical coagulation is
performed to remove turbidity, true and apparent colour, harmful bacteria and other
pathogens algal and other plankton organisms and taste and odour producing substances.
The laboratory studies of chemical coagulation are often required to determine the
best chemical or combination of chemicals and amounts needed to get a desired objective in
water, sewage and industrial waste treatment practice. The result obtained serve as the basis
of design and operation of treatment facilities.
AIM
To determine the optimum dosage of Alum required for turbidity.
APPARATUS
1. Jar test apparatus
2. Glass beakers
3. Pipette
4. Nephelometer
5. pH meter
REAGENTS
1. Alum / Ferric chloride
PROCEDURE
1. Measure the initial pH and turbidity for whole sample.
2. Measure 500 ml quantities of above wastewater sample into each of 6 beakers in
series.
3. Keep each beaker below each paddle and lower the paddles, such that each one is
about 1cm above the bottom.
4. Pipette 1, 1.5, 2, 2.5, 3, 3.5 ml of the Ferric chloride solution into the test samples.
27. 5. Immediately run the paddles at 100 rpm for 1 minute.
6. Reduce the speed to 30–40 rpm and run at this rate for 10 minutes.
7. Stop the machine, lift out the paddles and allow to settle for 2 minutes
8. Carefully take a small amount (about 100ml) of settled waste water from top of each
beaker without disturbing the settled sediments.
9. Find the residual turbidity of the supernatant using nephelometer.
10. Plot a graph with Ferric chloride dosage along x-axis and turbidity along y-axis.
11. The dosage of alum, which represents least turbidity, gives Optimum Coagulant
Dosage
12. Repeat steps 1–10 with higher dose of alum, if necessary.
OBSERVATION
Trial Initial turbidity in Ferric chloride dosage Final turbidity Efficiency
no. NTU in ml NTU %
28. CALCULATION
Efficiency of the Ferric chloride dosage = Initial turbidity - Final turbidity X 100
Initial turbidity
MODEL GRAPH
X-axis = Ferric chloride dosage
Y-axis = Turbidity
RESULT
Optimum coagulant dosage =...........
Efficiency
29. Ex.NO:8
Date:
Determination of residual chlorine and
available chlorine in bleaching powder
Aim
To determine the residual chlorine& available chlorine in the water sample
Principle
Bleaching powder is commonly used as a disinfectant. The chlorine present in the bleaching
powder gets reduced with time. So, to find the exact quantity of bleaching powder required,
the amount of available chlorine in the sample must be found out.
Chlorine will liberate free iodine from potassium iodide solution when its pH is 8 or less. The
iodine liberated, which is equivalent to the amount of active chlorine, is titrated with standard
sodium thiosulphate solution using starch as indicator.
Apparatus:
1. Erlemeyer flask (250 mL)
2. Bottle
3. Beaker (250 mL)
4. Measuring cylinder
5. Dropper
6. Stirrer
Reagents
1. Acetic acid
2. Potassium iodide
3. Sodium thiosulphate 0.025N
4. Starch indicator
Residual Chlorine In Bleaching Powder
Procedure
1. Take 100ml of sample in a conical flask and add 5ml acetic acid. The point after the
addition of acetic acid should be between 3 and 4.
2. Add approximate 1gm of KI crystal and mix with a stringing rod for about 15 minutes
keeping it away from the direct sunlight.
3. Add a few drops of starch indicator and titrate against 0.02N sodium thiosulphate
until the contents turn colourless from blue
30. Tabulations
Burette solution sodium thiosulphate
Pipette solution chlorinated water sample
Indicator starch
End point blue to colourless.
S.No Vol of
bleaching
powder
solution
(ml)
Initialburetter
eading(ml)
Final
burette
reading(ml)
Concurrentburett
e
reading
(ml)
Vol of
sodium
thiosulph
ate(ml)
Calculation
Chloride in mg/Lt = (ml of AgNO3 x Normality of AgNO3 x 1000 xEquivalent weight of
Chlorine)
---------------------------------------------------------
Volume of Sample
RESULT
The amount of residual chlorine determined from the given sample is ________mg/l
31. Available Chlorine In Bleaching Powder
Materials required
1. Standard (0.02N) Potassium dichromate (K2Cr2O7)
Dissolve 0.09806 g of K2Cr2O7 in 100 ml distilled water.
2. 0.02 N Sodium thiosulphate solution: Dissolve 2.5 g sodium thiosulphate in 500 ml distilled
water.
3. 20% Potassium iodide solution: Dissolve 20 g KI in 100 ml distilled water and store in amber
coloured bottle.
4. 0.5% Starch solution: Dissolve 0.5 g starch in 100 ml distilled water by boiling.
5. 2N H2SO4 acid: Dilute 2.85 ml of conc. H2SO4 acid to 50 ml with distilled water.
6. 4 N HCl acid: Dilute 35.6 ml of conc. HCl to 100 ml with distilled water.
Procedure
Dissolve 1g bleaching powder in 1 litre of distilled water in a volumetric flask, and stopper
thecontainer.
Place 5 mL acetic acid in an Erlenmeyer flask and add about 1g potassium iodide crystals.
Pour 25 mL of bleaching powder solution prepared above and mix with a stirring rod.
Titrate with 0.025 N sodium thiosulphate solution until a pale yellow colour is obtained.
(Deep yellow changes to pale yellow.)
Add 1mL of starch solution and titrate until the blue colour disappears.
Note down the volume of sodium thiosulphate solution added (V1).
Take a volume of distilled water corresponding to the sample used.
Add 5 mL acetic acid, 1g potassium iodide and 1 mL starch solution.
If blue colour occurs, titrate with 0.025 N sodium thiosulphate solution until the blue colour
disappears.
Record the volume of sodium thiosulphate solution added (A1).
If no blue colour occurs, titrate with 0.025 N iodine solution until a blue colour appears.
Note down the volume of iodine (A2).
Then, titrate with 0.025 N sodium thiosulphate solution till the blue colour disappears.
Record the volume of sodium thiosulphate solution added (A3). Note down the difference
between the volume of iodine solution and sodium thiosulphate as A4(A4=A2- A3).
32. Observation
Bleaching powder solution x Standard sodium thiosulphate solution (0.025 N)
Distilled water × Standard sodium thiosulphate solution (0.025 N)
Distilled water x Standard iodine solution (0.025N)
33. Available chlorine is calculated by using the following formula
Available chlorine (g %) =[(X x N ) /V] X [35.46 /1000] X [1000 /W ] X 100
Where,
X-Titrate value
N-Normality of sodium thiosulphate used
V- Volume of sample taken for titration
W - Weight of sample dissolved in 1000 ml distilled water
35.46 - Equivalent weight of chlorine
Results
Available chlorine in the given bleaching powder is. ..........%
34. Ex.No: 9
Date:
Determination of residual oil & grease
Introduction:
Oil and grease is any material recovered as a substance soluble in petroleum ether, hexane or n-
hexane. It includes other materials extracted by the solvent from an acidified sample such as
sulphur compounds, certain organic dyes and chlorophyll. Oil and grease are defined by the
method used for their determination. The oil and grease content of domestic industrial wastes and
of sludges, is an important consideration in the handling and treatment of these materials for
ultimate disposal. When treated effluents are discharged in water body, it leads to environmental
degradation. Hydrocarbons, esters, oils, fats, waxes and high molecular weight fatty acids are the
major materials dissolved by hexane. All these materials have a ‗greasy feel‘. Three methods for
oil and grease estimations are (i) the partition-gravimetric method, (ii) the partition infrared
method and (iii) the Soxhlet extraction method. Though methods-(i) does not provide the needed
precision, it is widely used for routine analysis of samples because of its simplicity and it needs
no special instrumentation and (ii) is identical to hydrocarbons. In method (iii) adequate
instrumentation allows for the measurement of as little as 0.2mg oil and grease.
Partition-gravimetric method
Principle
Dissolved or emulsified oil and grease is extracted from water by intimate contact with n-hexane,
petroleum ether (40°C/60°C) or hexane. Unsaturated fats and fatty acids oxidise readily hence
precautions regarding temperature to solvent vapour displacement are included in the procedure.
Apparatus and equipment
a. Separatory funnel, 1L with TFE (Teflon) stopcock
b. Distilling flask, 125mL
c. Water bath
d. Filter paper, 110mm dia. (Whatman No. 40 or equivalent).
e. Weighing balance
Reagents and standards
a. Hydrochloric acid: HCl (1+1)
b. n-hexane
c. Petroleum ether (BP 40°C-60°C) or Hexane
d. Anhydrous sodium sulphate-Na
2
SO
4
The solvent should leave no measurable residue on evaporation; distill if necessary. Petroleum
ether 40°C/60°C or hexane can also be used. Plastic tubes should not be used to transfer solvent
between containers.
Sample collection, preservation and storage
Collect a representative sample and preserve as per the procedure mentioned in Chapter 9. Collect
separate sample for oil and grease and do not subdivide in the laboratory. Samples collected at
35. different intervals of time may be examined individually for knowing average concentration of oil
and grease. The glass bottle container should be rinsed with the solvent to remove contaminants
adhered to the side walls.
Procedure
a. Collect about 1Lsample and mark sample level in bottle for later determination of sample
volume. Acidify to pH 2 or lower; generally, 5mL HCl (1+1) is sufficient. Transfer to a
separatory funnel. Carefully rinse sample bottle with 30mL n-hexane and add the solvent
washings to separatory funnel.
b. Preferably shake vigorously for 2 min. However, if it is suspected for a stable emulsion, shake
gently for 5 to 10 min.
c. Let the layers separate. Drain solvent layer through a funnel containing solvent-moistened filter
paper and 10g Na
2
SO
4
into a clean, tared distilling flask. If a clear solvent layer cannot be
obtained and emulsion exists, centrifuge the solvent and emulsion. Transfer centrifuged material
to a separating funnel and drain solvent layer through a funnel with a prerinsed filter paper and 10
g Na
2
SO
4
.
d. Extract twice more with 30mL solvent each but first rinse sample container with each solvent
portion. Combine extracts in tared distilling flask and wash filter paper with an additional 10 to
20mL solvent.
e. Distill solvent from distilling flask in a water bath at 70°C for solvent recovery. Place flask on
a water bath at 70°C for 15 min and draw air through it with applied vacuum for the final 1min
after the solvent has evaporated. If the residue contains visible water, add 2mL acetone, evaporate
on a water-bath and repeat the addition and evaporation until all visible water has been removed.
Cool in a desiccator for 30 min and weigh.
Calculations
Total gain in weight A, of tared flask and less calculated residue B, from solvent blank is the
amount of oil and grease in the sample.
Mg/L, Oil and grease = (A –B) x 1000 / mL sample
Along with the results, mention the solvent used for extraction.
Results
The amount of oil and grease in sample ……………
36. Ex.No: 10
Date :
Determination of suspended, settleable, volatile
and fixed solids
AIM
The aim of the experiments is to determination of suspended, volatile, fixed
and settleable solids in wastewater.
APPARATUS
3. Porcelain evaporating dishes of 150–200 ml capacity
4. Steam bath
5. Drying oven
6. Desiccators
7. Analytical balance or monopan balance
8. Filter paper (preferably of glass fibre)
9. Electric muffle furnace
10. Imhoff cone
Principle
―Total solids‖ is the term applied to the material left in the vessel after evaporation
of a sample of water/waste water and its subsequent drying in an oven at a definite
temperature. Fixed solids is the residue remaining after ignition for 1 hour at 550°C. The
solid portion that is volatilised during ignition is called volatile solids. It will be mostly
organic matter. Waters that are low in organic matter and total mineral content and are
37. intended for human consumption may be examined under 103–105°C or 179–181°C. But
water containing considerable organic matter or those with pH over 9.0 should be dried at
179–181°C. In any case, the report should indicate the drying temperature. The sample is
filtered and the filtrate evaporate in a weighed dish on a steam bath, the residue left after
evaporation is dried to constant weight in an oven at either 103–105°C or 179–181°C. The
increase in weight over that of the empty dish represents total dissolved solids and includes
all materials, liquid or solid, in solution or otherwise, which passes through the filter and
not volatilised during the drying process. The difference between the total solids and the
total dissolved solids will give the total suspended solids. The dishes with the residue
retained after completion of the tests for total solids and total dissolved solids are subjected
to heat for 1 hour in a muffle furnace held at 550°C. The increase in weight over that of the
ignited empty vessel represents fixed solids in each instance.The difference between the
total dissolved/total suspended solids and the corresponding fixed solids will give volatile
solids in each instance. All the quantities should be expressed in mg/L. Settleable matter in
surface and saline waters as well as domestic and industrial wastes may be determined and
reported on a volume basis as millilitre per litre.
PROCEDURE
1. Total solids
Ignite the clean evaporating dishes in the muffle furnace for 30 minutes at 550°C
and cool in a desiccator.
Note down the empty weight of the dish (W1).
Pour a measured portion (10 ml) of the well-mixed sample into the
dish.
Transfer the dish to an oven maintained at either 103–105°C or 179–181°C and
dry it for 1 hour.
Allow the dish to cool briefly in air before placing it, while still warm in a
desiccator to complete cooling in a dry atmosphere.
Weigh the dish as soon as it has completely cooled (W2).
38. Weight of residue = (W2 – W1) mg.
W2 and W1 should be expressed in mg.
1. Total fixed solids
Keep the same dish used for determining total residue in a muffle
furnace for 15minutes at 550°C.
Allow the dish to partially cool in air until most of the heat has dissipated,
then transfer to a desiccators for final cooling in a dry atmosphere.
Weigh the dish as soon as it has cooled (W3).
Weight of total fixed residue = (W3 – W1) mg.
W3 and W1 should be expressed in mg
Total dissolved solids
Filter a measured portion of the mixed sample (10 ml) through a filter paper
and collect the filtrate in a previously prepared and weighed evaporating
dish.
Repeat the steps 3 to 6 outlined in total solids procedure.
Weight of dissolved solids = (W5 – W4) mg.
W4 = Weight of empty evaporating dish in mg.
W5 = Weight of empty evaporating dish in mg + Residue left after evaporating
the filtrate in mg.
1. Total suspended solids = Total solids–Total dissolved solids.
2. Total volatile solids= Total solids – Total fixed solids.
39. OBSERVATION
Sl. Item Samples
no.
1 Volume of sample taken
2. Wt. of empty evaporating dish = W1 mg (For total dissolved solids)
3. Wt. of dish + total solids = W2 mg
4. Total solids = (W2 – W1) mg
5. Wt. of dish + fixed solids = W3 in mg
6. Fixed solids in mg = (W3 – W1)
7. Wt. of empty evaporating dish = W4 mg (For total dissolved solids)
8. Wt. of dish + total dissolved solids = W5 mg
9. Total dissolved solids = (W5 – W4) mg
10. Total solids in mg/l
11. Total fixed solids in mg/l
12. Total dissolved solids in mg/l
13. Total suspended solids in mg/l
14. Total volatile solids in mg/l
40. CALCULATION
1. mg/l of total solids = mg total solids × 1000
ml of sample
2. mg/l of total fixed solids = mg total fixed solids × 1000
ml of sample
3. mg/l of total dissolved solids = mg of total dissolved solids ×1000
ml of sample
4. mg/l of total suspended solids = mg/l of total solids – mg/l of total dissolved solids
5. mg/l total volatile solids = mg/l of total solids – mg/l of total fixed solids
RESULT
1. total solids = ___________mg/l
2. fixed solids = ___________mg/l
3. dissolved solids = ___________mg/l
4. suspended solids = ___________mg/l
5. volatile solids = ___________mg/l
41. EX.NO: 11
Date:
AIM
Determination Dissolved Oxygen and
BOD for the given sample
To determine the BOD in the given wastewater sample.
PRINCIPLE
If sufficient oxygen is available in wastewater, the useful aerobic bacteria will
flourish and cause the aerobic biological decomposition of wastewaterwhich will
continue until oxidation is completed.
The amount of oxygen consumed in this process is the BOD. Polluted waters will
continue to absorb oxygen for many months, and it is not practically feasible to determine
this ultimate oxygen demand.
APPARATUS REQUIRED
BOD incubator
BOD bottle (300ml)
Conical flask
Burette
Measuring jar
REAGENTS REQUIRED
1. Sodium thio-suiphateb(0.01N)
2. ManganousSulphate
3. Alkai- iodide
4. Conc.H2SO4
5. Starch
42. PROCEDURE
1. Distilled water is aerated for 4 hours to attain saturated Dissolved Oxygen (DO)
level. In distilled water 1 ml of each nutrients (Phosphate buffer, Magnesium
Sulphate, Calcium Chloride and Ferric Chloride) and 1 ml of pre acclimatized
seed per 1 litre of distilled water is added.
2. Two BOD bottles are taken. The wastewater sample 5 ml is taken in the BOD
bottles and then 245ml of aerated water is filled. DO test is conducted for the one
BOD bottle sample by the following steps and initial DO is noted.
3. 1 ml of Manganese Sulphate solution is added, followed by 1 ml of Alkali –
Iodide –
Azide reagent. Then the bottle is mixed twice and allowed to precipitate settle for
5 minutes.
4. 1 ml of Conc.Sulphuric Acid is added slowly and mixed twice. 200 ml of sample
is taken and titrated against Sodium thioSulphate solution with starch indicator.
5. Disappearance of blue colour is taken as end point. Volume of Sodium
thioSulphate consumed is noted.
6. Another bottle is placed in incubator at 20⁰ C. After 5 days DO test is conducted
and final DO is noted.
43. CALCULATION
D.O. Calculation
Initial D.O.
Sodium thiosulphateVs given sample
S.no Volume of Burette readings (ml) Concurrent Volume of
given burette reading Sodium thio
sample (ml) (ml) sulphate (ml)Initial Final
CALCULATION
DO in (mg/l) = (V2 x N x 8 x 1000)/V1
V1 = Volume of water sample in ml.
V2 = Volume of Sodium thiosulphate consumed in ml.
N = Normality of sodium thiosulphate
44. CALCULATION
DO in (mg/l) = (V2 x N x 8 x 1000)/V1
BOD CALCULATION
BOD5 (mg/L) = [(Initial DO – Final DO) x dilution factor]
RESULT
BOD5 of given sample at 20
o
C in mg/l =________
S.no Volume of Burette readings (ml) Concurrent Volume of
given burette reading Sodium thio
sample (ml) (ml) sulphate (ml)Initial Final
45. Ex.No:12
Date:
Determination of COD for given sample
AIM
To determine the chemical oxygen demand in the wastewater
sample. PRINCIPLE
The organic matter present in sample gets oxidized completely by K2Cr2O7 in the
presence of H2SO4 to produce CO2 and H2O. The excess K2Cr2O7 remaining after the
reaction is titrated with Fe(NH4)2(SO4)2. The dichromate consumed gives the O2 required
to oxidation of the organic matter.
APPARATUS REQUIRED
1. COD Reactor
2. Burette with stand & Pipette
3. Measuring jar
4. Reflux apparatus
5. Beakers
6. Conical flask
7. Hot plate
CHEMICALS REQUIRED
1. Std. Potassium dichrornate
2. Conc. Sulphuric acid
46. 3. Ferroin indicator solution
4. Std. Ferrous ammonium sulphate solution
5. Mercuric Sulphate
PROCEDURE
1. Place 0.4g of HgSO4 in the reflux flask.
2. Add 20ml of sample (or an aliquot diluted to 20ml)
3. 10ml of more concentrated dichromate solution are placed into flask together
with glass beeds.
4. Add slowly 30ml of H2SO4 containing Ag2SO4 and mix thoroughly.
5. Connect the flask to condenser. Mix the contents thoroughly before heating.
6. Improper mixing results in bumping and the sample may be blown out.
7. Reflux for a minimum period of 2 hours. Cool and wash down the condenser with
distilled water.
8. Dilute the sample to make up 150ml and cool.
9. Titrate excess K2Cr2O7 with 0.1N Fe(NH4)2SO4 using ferroin indicator.
10. Sharp colour change from blue green to wine red indicates the end point.
RESULT
The COD of the given sample in mg/l is -----------------------
