CIVIL ENGINEERING GROUP

BIRLA INSTITUTE OF TECTNOLOGY & SCIENCE

PILANI-RAJASTHAN-333031

PUBLIC HEALTH ENGINEERING LABORATORY

___________________________________________________
CONTENTS

S.No. Name of the experiment Page No

1. Determination of acidity & alkalinity 2

2. Determination of dissolved oxygen 6

3a. Determination of iron 8

3b. Determination of residual chlorine 10

4a. Determination of chloride 12

4b. Determination of multiparameter sonde to measure 14

water quality parameters
5a. Determination of hardness 15

5b. Determination of calcium 17

6. Determination of solids, pH and turbidity 19

7. Determination of sulphate 25

8. Determination of fluoride 27

9. Jar test 29

Page | 1
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF ACIDITY
Principle:

Acidity is the measure of alkali neutralization power of a solution. Both

carbon dioxide and mineral acidity can be measured by means of standard
solution of alkalinity reagents with the help of proper indicator. Mineral
acids are measured by titration to a pH of about 3.7, the methyl orange (MO)
end point. For this reason, mineral acidity is also called methyl orange
acidity. Titration of a sample to the phenolphthalein acidity.

Reagents:

Phenolphthalein indicator
Methyl orange indicator
Standard NaOH solution, 0.02N

Apparatus:

Conical Flask
Pipette
Burette
Measuring cylinder

Procedure:

1. Take 25 mL of sample in a conical flask.

2. Add 3 drops of methyl orange indicator. The color of the sample turns
to red.
3. Titrate the sample with NaOH solution until the color of the sample
changes to yellow. Note down the volume of NaOH consumed (V1).
4. Add 3 drops of phenolphthalein indicator. The sample will be colorless.
If it is pink, then there is no phenolphthalein acidity. 5. Titrate the
sample with NaOH until the sample turns to pink. Note down the
volume of NaOH consumed (V2).
Page | 2
Calculation:

𝐴× 𝑁 ×50000
Acidity (mg/L CaCO3) =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Where,

N=Normality of NaOH
A= mL of NaOH consumed

Reagent Preparation:

1. Sodium Hydroxide (NaOH):

To prepare sodium hydroxide of 1N, dissolve 40 g of sodium

hydroxide in 1 liter of distilled water.

2. Phenolphthalein indicator:

To prepare phenolphthalein indicator, dissolve 5 gm of

phenolphthalein di sodium solution in distilled water and dilute to
500 ml.

3. Methyl Orange indicator:

To prepare methyl orange indicator, dissolve 500 mg of methyl

orange powder in distilled water and dilute it to 1000 ml.

Page | 3
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF ALKALINITY

Principle:

Alkalinity of water is its acidic-neutralizing capacity. Both

phenolphthalein and methyl orange alkalinity of water can be measured
by titration with a standard solution of a strong mineral acid.
Phenolphthalein alkalinity is measured by titration to a p H of about 8.3,
the phenolphthalein end point. Titration of a water sample to the methyl
orange (MO) end point of pH 3.7 measured total alkalinity of the water
sample.

Reagents:

Phenolphthalein indicator
Methyl orange indicator
Standard H2SO4 solution, 0.02N

Apparatus:

Conical flask
Pipette
Burette
Measuring cylinder

Procedure:

1. Take 25 mL of sample in a conical flask.

2. Add 3 drops of phenolphthalein indicator. The color of the sample
turns to pink. If it is colorless then there is no phenolphthalein
alkalinity.
3. Titrate the sample with H2SO4 solution until the sample becomes
colorless. Note down the volume of H2SO4 consumed (V). 4. Add 3
drops of methyl orange. The sample will be yellow. 5. Titrate the
sample with H2SO4 until the sample turns to red. Note down the
volume of H2SO4 consumed (V2).
Page | 4
Calculation:

𝐴× 𝑁 ×50000
Alkalinity (mL/CaCO3) =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Where,

N=Normality of H2SO4
A= mL of H2SO4 consumed

Reagent preparation:

1. Sulphuric Acid:

To prepare sulphuric acid of 0.02 N, dissolve 20 ml of 1 N sulphuric

acid with one liter of distilled water slowly.

2. Phenolphthalein indicator:

To prepare phenolphthalein indicator, dissolve 5 gm of

phenolphthalein di-sodium solution in distilled water and dilute to
500 ml.

3. Methyl Orange indicator:

To prepare methyl orange indicator, dissolve 500 mg of methyl

orange powder in distilled water and dilute it to 1000 ml.

Page | 5
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF DISSOLVED OXYGEN

Principle:

Dissolved oxygen is measured by Winkler method. In this method, DO is

first fixed as MnO2 by adding manganous sulphate (MnSO4) and alkali –
iodide (NaOH + KI). Then sulphuric acid is added to liberate free iodine
from potassium iodide (KI). This liberated is treated with a sodium
thiosulphate (Na2S2O3) with starch as indicator. Sometimes sodium azide
(NaN3) is used to reduce the interference of nitrate and ferric ion present
in water.

Mn2+ + 2OH- + (1/2) O2 = MnO2 + H2O

MnO2 + 2I- + 4H+ = Mn2+ + I2 + 2H2O
2Na2S2O3 + I2 = 2NaI + Na2S4O6
Starch + I2 = Starch iodine (Blue)

Apparatus:

Conical flask
Pipette
Burette
Measuring cylinder
BOD bottle

Procedure:

1. Collect sample in BOD bottle.

2. Add 2 mL of MnSO4 solution followed by 2 mL alkali – iodide
solution. The top of the pipette should be below the liquid level
when adding these solutions. Shake the sample thoroughly and then
allow it to settle the flocculants at the bottom.
3. Add 2 mL of concentrated H2SO4. Due to liberation of free iodine the
sample turns yellow.
4. Take 203 mL of the sample in a conical flask.

Page | 6
5. Titrate with 0.025 N sodium thiosulphate solution until the yellow
colour of liberated iodine becomes faint.
6. Add 1 mL of starch solution and titrate until blue colour becomes
colourless.
7. Note down the total sodium thiosulphate solution consumed.

Calculation:

For titration 0f 203 mL sample, 1.0 mL 0.025 N Na2S2O3 = 1.0 mg DO/L

Reagent Preparation:

1. Manganous Sulphate (MnSO4) Solution:

To prepare manganous sulphate solution, dissolve 400g of MnSO4.

2H2O or 364g of MnSO4.H2O in distilled water and dilute to 1.0 L

2. Alkali-Iodide-Azide Solution:

To prepare alkali – iodide solution, dissolve 500g NaOH (or 700 g

KOH),135 g NAI (or KI) and 10g NaN3 in distilled water and then
dilute to 1.0 L

3. Sodium Thiosulphate Solution (0.025N):

To prepare sodium thiosulphate solution (0.025 N), dissolve 6.25g of

Na2S2O3, 5 H20 in 1L of fresh boiled distilled water

4. Starch Indicator:

To prepare starch indicator, dissolve 5 g of starch in 1L of boiled

distilled water

Page | 7
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF IRON

Principle:

Ferric iron is determined by producing reddish brown colour ferric

thiocyanate by adding potassium thiocyanate in acid medium. The ferrous
ions are converted to ferric ions upon oxidation using potassium
permanganate.

Fe3+ + 3KCNS = Fe (CNS)3 + 3K+

Apparatus:

Nessler’s tube
Pipette
Burette
Measuring cylinder

Procedure:

1. Take 100 mL of sample and distilled water in two separate Nessler’s

tubes.
2. Add 5 mL of concentrated HCl and 2 drops of potassium permanganate
to each tube.
3. Add 5 mL of potassium thiocyanate to each tube. The sample will turn
to reddish brown.
4. Add standard iron solution from burette to the distilled water until the
colour of distilled water matches with sample.
5. Note down the volume of standard iron solution required.

Calculation:
𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑖𝑟𝑜𝑛 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑥 𝑡𝑖𝑡𝑟𝑎𝑡𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 𝑥 1000
mg of iron/L =
𝑚𝐿 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Page | 8
Reagent Preparation:

1. Potassium permanganate (0.02 N):

To prepare potassium permanganate, dissolve 6.32 gm of potassium

permanganate in 1 L distilled water.

2. Potassium thiocyanate:

To prepare potassium thiocyanate, dissolve 20 gm of potassium

thiocyanate in 1 L distilled water.

3. Ferrous ammonium sulfate:

First slowly add 20 ml conc. H2SO4 to 50 Ml distilled water and

dissolve 1.404g of Fe(NH4)2(So4)2.6H2O.Then add 0.1 N potassium
permanganate drop wise until a faint colour persists. Dilute to
1000mL with water and mix; 1.0 mL = 0.2 mg Fe. Dilute the solution
to 20 times to get 1.0 Ml = 0.01 mg Fe.

Page | 9
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF RESIDUAL CHLORINE

Principle:

Chlorine will liberate free iodine from potassium iodide (KI) solutions at
pH 8 or less. This librated iodine is treated with a standard solution of
sodium thiosulphate (Na2S2O3) with starch as indicator.

Cl2 + 2KI = I2 + 2KCl

2Na2S2O3 + I2 = 2NaI + Na2S4O6
Starch + I2 = Starch iodine (Blue)

Apparatus:

Conical flask
Pipette
Burette
Measuring Cylinder

Procedure:

1. Place 5 mL of glacial acetic acid in a flask. Add about 1 g of KI

estimated on a spatula.
2. Pour 100 mL sample in the flask and mix.
3. Titrate with 0.01N sodium thiosulphate solution until the yellow colour
of liberated iodine becomes faint.
4. Add 1 mL of starch solution and titrate until blue color solution becomes
colorless.
5. Note down the total sodium thiosulphate solution consumed. 6. Repeat
the above procedure for 100 mL distilled water (i.e., blank)

Page | 10
Calculation:
(𝐴−𝐵)× 𝑁×35450
mg of chloride as Cl2/L =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Where,

A = mL of sodium thiosulphate for sample

B = mL of sodium thiosulphate for blank
N = normality of Na2S2O3

Reagent Preparation:

1. Standard sodium thiosulphate solution (0.01N):

To prepare sodium thiosulphate, dissolve 2.5 g of Na 2S2O3. 5H2O in 1

L of fresh boiled distilled water.

2. Starch indicator solution:

To prepare starch solution, dissolve 5 g of starch in 1 L boiled distilled

water.

3. Potassium iodide (KI) crystal

Page | 11
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF CHLORIDE

Principle:

In a neutral or slightly alkaline solution, potassium chromate can indicate

the end point of silver nitrate titrant of chloride. Silver chloride is
precipitated quantitatively before red silver chromate is formed.

AgNO3 + Cl- → AgCl ↓ + NO3-

2AgNO3 + K2CrO4 → Ag2CrO4 + 2KNO3

Apparatus:

Conical flask
Pipette
Burette
Measuring Cylinder

Procedure:

1. Take 50 ml of sample in conical flask and add 50 ml of distilled water.

2. Check whether the pH of sample is 7-10. If not so adjust it by H2SO4 or
NaOH.
3. Add 1 ml K2CrO4 indicator.
4. Titrate it against 0.0141 N AgNO3 till yellowish solution turns red. 5.
Note the volume of AgNO3 consumed
5. Do the above steps for blank.

Calculation:

(𝐴−𝐵)× 𝑁×35450
mg Cl-/L =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Where,

Page | 12
A= mL of AgNO3 consumed for the sample
B= ml of AgNO3 consumed for blank
N= normality of AgNO3

Reagents:

1. Potassium chromate indicator:

To prepare potassium chromate, dissolve 50 g of K2CrO4 in a little

distilled water. Add AgNO3 solution until a definite red precipitation is
formed. Let stand 12 hours, filter and dilute to 1 L with distilled water.

2. Standard silver nitrate titrant, 0.0141 N:

To prepare silver nitrate, dissolve 2.395 g of silver nitrate (AgNO3) in 1

L distilled water.

3. Dilute sulphuric acid (H2SO4) with distilled water.

4. Dilute sodium hydroxide (NaOH) with distilled water.

5. pH paper

Page | 13
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF
MULTIPARAMETER SONDE TO MEASURE
WATER QUALITY PARAMETERS

Multiparameter Sonde / Mete is a compact sonde or sensor which could

monitor temperature, pH value, turbidity, conductivity, and dissolved
oxygen in one instrument. This equipment is unified for power supply and
communication, which will greatly simplify the electrical structure. It
reflects the quality of the water sample, forecasts the development trend of
water quality, and provides a scientific basis for the planning, development,
management, utilization, and prevention of water pollution.
Multiparameter Sondes Applications
• Water quality inspection of rivers and lakes
• Industrial and mining enterprises, detection of urban sewage discharge
• Water quality monitoring of petrochemical, chemical, power
generation, pharmaceutical, food, electronic, water plant, etc
• Water quality inspection of urban parks
• Smart city water quality detection

Apparatus:
YSI DSS pro kit

Procedure:
(Write the procedure of the experiment you performed.)

Page | 14
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF HARDNESS

Principle:

Ethylenediaminetetraacetic acid and its sodium salt (EDTA) form a cheated

soluble complex when added to a solution of certain metal cations. If a small
amount of a dye such as Eriochrome Back T (EBT) is added to an aqueous
solution containing calcium and magnesium ions at a pH of 10±0.1, the
solution becomes wine red. If EDTA is added as titrant, the calcium and
magnesium will be complexed and when all of the magnesium and calcium
has been complexed the solution turns from wine red to blue, making the
end point of titration.

Apparatus:

Conical flask
Pipette
Burette
Measuring cylinder

Procedure:

1. Take 25 mL of sample to in a conical flask and add 25 mL of distilled

water.
2. Add 2 ml of ammonia buffer to give a pH of 10 to 10.1. 3. Add small
amount of EBT indicator to get wine red colour. 4. Titrate it against 0.01N
EDTA till the wine red colour turns to blue. 5. Note the volume of EDTA
consumed.

Page | 15
Calculation:

𝐴 × 𝑓 ×1000 𝐴 × 1 ×1000
Hardness (mg/L as CaCO3) = = = 40 × 𝐴
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 25

Where,

f = mg CaCO3 equivalent to 1.0 mL EDTA titrant = 1

A = mL of EDTA consumed

Reagent Preparation:

1. Buffer solution:

To prepare buffer solution, dissolve 16.9 g of ammonium chloride

(NH4Cl) in 143 mL concentrated ammonium hydroxide (NH4OH) and
dilute to 250 mL with distilled water.

2. Eriochrome Black T:

To prepare Eriochrome Black T, mix 0.5 to 1.0 gm of charcoal dye in

100 ml of ethylene glycol.

3.Standard EDTA solution, 0.01N (1 mL = 1 mg CaCO3):

To prepare EDTA solution, dissolve 3.723 g of di-sodium salt of EDTA

in 1 L distilled water.

Page | 16
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF CALCIUM

Principle:

When ethylenediaminetetraacetic acid (EDTA) or its salts are added to

water containing both calcium and magnesium, it combines first with the
calcium. Calcium can be determined directly, with EDTA, when the pH is
made sufficiently high that the magnesium is largely precipitated as the
hydroxide and an indicator is used that combines with calcium only.
Several indicators such as murexide (ammonium perpurate) give a colour
change when all of the calcium has been complex by the EDTA at a pH of
12-13.

Apparatus:

Conical flask
Pipette
Burette
Measuring cylinder

Procedure:

1. Take 50mL of sample in a conical flask and boil for 1minute. 2. Allow
it to cool.
2. Add 2mL of NaOH solution.
3. Add 0.1 – 0.2g of murexide indicator and stir it to get pink colour. 5.
Titrate it against 0.01N EDTA slowly till the pink colour turns to purple.
6. Note the volume of EDTA consumed.

Page | 17
Calculation:
𝐴 × 𝐵 ×400.8
mg/L Ca2+ /L =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

𝐴 × 𝐵 ×1000 𝐴 × 1 ×1000
Calcium hardness (mg/L as CaCO3) =
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒
= 50
=

= 20 × 𝐴

Where,

A = mL of EDTA consumed.
B = mg of CaCO3 equivalent to 1.0mL EDTA titrant = 1.

Reagent Preparation:

1. Sodium Hydroxide (NaOH):

To prepare sodium hydroxide of 1N, dissolve 40 g of sodium

hydroxide in 1 liter of distilled water.

2. Standard EDTA solution:

To prepare ethylenediaminetetraacetic acid (EDTA), dissolve 3.723 g

of di - sodium salt of EDTA in 1 liter of distilled water.

Page | 18
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF SETTLEABLE SOLIDS AND TOTAL

SOLIDS

Apparatus:

Imhoff cone
China bowl
Weight balance

Procedure:

1. Shake the sample thoroughly and fill the cone up to 1 L mark by sample.
2. Leave it for 1 hour to settle the solids at the bottom of the cone. 3. Note
down the volume of the settled solids.

Procedure for TOTAL SOLIDS:

1. Take weight of dry empty china bowls.

2. Shake the sample thoroughly.
3. Pour 100 mL of sample in the bowls and keep in the oven at a
temperature of 100 – 110° C for 24 hours.
4. Take the weight of the bowls and the solid residue.

Calculation:
(𝐹𝑖𝑛𝑎𝑙 𝑤𝑡.𝑜𝑓 𝑐ℎ𝑖𝑛𝑎 𝑏𝑜𝑤𝑙−𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑤𝑡.)
Total solid content (mg/L) = × 1000
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Page | 19
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF TOTAL SOLIDS

TDS Measurement

A large number of slats are found dissolved in natural waters, the common
ones are carbonates, bicarbonates, chlorides, sulphates, phosphates, and
nitrates of calcium, magnesium sodium, potassium, iron, manganese etc. A
high content of dissolved solids elevates the density of water, water
organisms, reduce solubility of gases like oxygen and utility of water for
drinking, irrigational and industrial purposes. It is especially an important
parameter in the analysis of saline lake, costal and marine waters. This
factor is often expressed in ppm (mg/l) or ppt (gm/l).

Apparatus:

Deluxe Water and soil analysis kit

Beaker 200mL

Procedure for TOTAL SOLIDS:

1. Clean the TDS cell with distilled water, dry it and connect to TDS input.
2. Put the function switch at TDS position.
3. Dip the TDS cell in solution under test and determine its value on display
in ppt (gm/L).

Reagent preparation:
Dissolve 0.5232 gm Potassium Chloride (KCL) AL grade, dried at
180 deg C for 1 hour in distilled water and dilute to 1000 ml. The
TDS of the solution will be having a value of 650 ppm.

Page | 20
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF pH

Principle:

The glass electrode method is used to measure the pH of water. When a

pair of electrodes namely pH sensitive glass electrode and a reference
electrode are dipped I am aqueous solution, they generate electromagnetic
field which is proportional to the pH of the solution.

Reagents:

Standard pH solutions: pH 4, 7 and 9.2

Apparatus:

pH meter
Beaker

Procedure:

1. Switch on the pH meter and allow it to warm up.

2. Set the instrument at the room temperature.
3. Dip the electrode in pH 7 solution. If the pH value shown by the
instrument is not 7, then set it to it.
4. Check the instrument with pH 4 and 9.2 solution.
5. After the standardization of the instrument measure the pH of the
solution.

Page | 21
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF TURBIDITY

Principle:

Turbidity in water is due to presence of suspended solids and it can be

measured by electrical instrument called turbidity meter. The source
(Tungsten lamp) in combination with optical components produce a
converging light beam, focused on the turbid sample. The light is scattered
by the suspended particles in the solution. The scattered light is sensed by
a photocell kept at 90° in the light path. The amount of scattered light sensed
by the photocell is a direct measure of the turbidity of the solution.

Procedure:

1. Switch on the turbidity meter and allow 10 – 15 minutes to warm up.

2. Set the appropriate range.
3. Set the “CALIB CONTROL” to maximum clockwise position. 4. Adjust
zero controls to get zero on display.
4. Remove the cuvette and replace with cuvette containing standard
solution.
5. Adjust “CALIB CONTROL” to display the required turbidity value.
6. The instrument is now ready for testing samples. Insert cuvette
containing unknown solution in the cell holder.
7. Note down the display.

Page | 22
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF TURBIDITY

Turbidity Measurement
Clarity of water is important in producing products for human consumption
in many manufacturing units, beverages products, food processes and
treatment plants, drawing of surface water supply commonly rely on
coagulation setting and filtration to ensure an acceptable product. The
clarity if natural body of water is a major determination of the condition and
productivity of that system.

Apparatus:

Deluxe Water and soil analysis kit

cuvette

Procedure:

1. Take out the Turbidity Sampler (TS) from brief case.

2. Connect the TS to the instrument sampler socket through TS connecting
lead.
3. Allow 2 mins warm up period after switching ON the turbidity function.
4. Take distilled water or blank solution in a cuvette, insert it is TS and close
the lid.
5. Adjust the display 000 by adjusting the zero set knob.
6. Now take another cuvette of standard solution (200 NTU), place it in TS.
7. Calibrate knob to read 200 NTU.
8. Again, check the display zero with cuvette containing distilled water or
blank solution.
9. Now instrument is ready to take measurement of unknown suspension.

Reagent preparation:

Page | 23
1. Hydrazine Sulphate: Weigh accurately 1 g of hydrazine sulphate and
dissolve it in turbidity free distilled water. Take 100 mL standard measuring
flask and place a funnel over it. Transfer it to a 100 mL standard flask and
make up to 100 ml using turbidity free distilled water.

2. Hexamethylene Tetramine: Weigh accurately 10 g of Hexamethylene

tetramine and dissolve it in turbidity free distilled water. Take 100 mL
standard measuring flask and place a funnel over it. Transfer it to a 100 mL
standard flask and make up to 100 ml

3.Standard 4000 NTU Solution: Mix 5 mL of hydrazine sulphate solution

and 5 mL of Hexamethylenetetramine solution in a 100 mL standard
measuring flask. Allow the mixture to stand for 24 hours. After 24 hours,
make up the volume to 100 mL using turbidity free distilled water. The
standard 4000 NTU solution is ready.

Note:- for making solutions of lower turbidity values, use the normality
equation, N1V1= N2V2

Page | 24
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF SULPHATE IN WATER AND

WASTEWATER

Principle:

Sulphate is precipitated in a hydrochloric acid solution as barium sulphate

(BaSO4) by the addition of barium chloride (BaCl2). The precipitation is
carried out near the boiling temperature and after a period of digestion the
precipitate is filtered, washed with warm distilled water until free of Cl-,
dried and weighed as BaSO4.

Apparatus:

Whatman filter paper (No.42)

Beaker
Pipette, measuring cylinder
Stirring rod
Heater
Dry oven
Filtering apparatus

Procedure:

1. Take 200ml of sample in a beaker.

2. Add 1-2 ml of HCl.
3. Heat the sample to boiling and while stirring gently, slowly add BaCl2
solution until precipitation appears to be completed and then add 2 ml
in excess.
4. Keep the sample for 2 hours.
5. Dry a Whatman filter paper (No.42) at 105°C for 1 hour, cool in
desiccator and weigh.
6. Filter BaSO4 at room temperature through the filter paper.
7. Wash precipitate with several small portion of warm distilled water.
8. Dry the filter paper at 105°C for 2 hours, cool in desiccator and weigh.

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Calculation:
(𝐹𝑖𝑛𝑎𝑙 𝑤𝑡.−𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑤𝑡.)𝑜𝑓 𝑓𝑖𝑙𝑡𝑒𝑟 𝑝𝑎𝑝𝑒𝑟
mg of SO42-/l = × 411.6
𝑚𝑙 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒

Reagent Preparation:

1. Barium chloride solution:

To prepare barium chloride solution, dissolve 100 g of BaCl 2. 2H2O

in 1 L of distilled water

Page | 26
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

DETERMINATION OF FLUORIDE

Principle:

For the determination of fluoride ion in water, the methods used are based
on the reaction between fluoride and zirconium dye lake. The fluoride
reacts with the dye lake dissociating a portion of it into colorless complex
ion (ZF-) and the dye. As the amount of fluoride is increased, the color
produced becomes progressively lighter in hue.

Apparatus:

Beaker
Pipette
Nessler tube

Procedure:

1. Take 100ml of sodium fluoride solution in ten Nessler tubes having

fluoride concentration 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 mg/l.
2. Take two samples (100ml) each for one source.
3. Add 5ml of acid zirconyl alizarin reagent to each Nessler tube.
4. Shake the Nessler tubes well by putting palm on the top.
5. Leave it for one hour for the completion of reaction.
6. Compare colour keeping Nessler tubes over a white tile.
7. Record the matched colour as result in mg/l.

Reagent Preparation:

1. Standard sodium fluoride solution (NaF):

Dissolve 221 mg of anhydrous sodium fluoride, NaF, in distilled water

and dilute to 1000 ml (1 ml = 100 μg F) to prepare stock solution. Dilute
100 ml stock solution to 1000 ml with distilled water (1 ml= 10 μg F).
Page | 27
2. Acid zirconyl alizarin:

Dissolve 300 mg of zirconyl chloride oxyhydrate, ZrOCl2.2H2O in 50 ml

of distilled water contained in a 1-liter glass stoppered volumetric flask.
Dissolve 70 mg of 3- alizarin sulfonic acid sodium salt in 50 ml distilled
water and pour slowly into zirconyl solution while stirring. This is the
zirconyl – alizarin reagent.

Prepare mixed acid solution by diluting 101 ml concentrated HCl to

approximately 400 ml of distilled water. Carefully add 33.3 ml of
concentrated H2SO4 to 400 ml of distilled water. After cooling, mix two
acids.

To the zirconyl – alizarin reagent, add the acid solution and add water to
1 liter, mark, and mix. The reagent colour changes from red to yellow.

Page | 28
 BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE
PILANI – RAJASTHAN – 333031

CIVIL ENGINEERING GROUP

PUBLIC HEALTH ENGINEERING LABORATORY

JAR TEST

COAGULATION AND FLOCCULATION

Coagulation and flocculation are an important part of water and wastewater

treatment. Coagulation for destabilization of a colloidal suspension results
in joining of minute particles by physical and chemical processes.
Flocculation results in motion of larger settle able structures by bridging.
These processes commonly used to remove suspended matter or colour.
Adsorption of ionic forms also occurs to varying degrees depending on the
constituents in the water and the wastewater.

The jar test is a laboratory technique for determining the most effective
coagulant, chemical dose, and operating pH for coagulation and
flocculation, aluminum or iron salts, hydrous metal oxide precipitates and
impurities.

Principle:

Metal salts hydrolyze in presence of natural alkalinity to form metal

hydroxide. The multivalent cations with the zero-potential forms metal
hydroxides which are good adsorbents and hence remove the suspended
particles by enmeshing them.

Al2 (SO4)3.18H20 + 3Ca (HCO3)2_--- 2Al (OH)3 + 3CaSO4 + 3CO2 + 14H2O

Objective:

To conduct jar test on a natural surface in order to estimate the optimum

dosage of aluminum sulphate or ferric sulphate for the removal of
suspended matter or colour and to observe the rate of floc formation and
sedimentation.

Page | 29
Procedure:

1. Analyze the water for pH, turbidity, and color after filtration and
alkalinity.
2. Calculate the amount of alkalinity required to react with the
maximum dosage of aluminum or ferric sulphate
3. If necessary, augment the natural alkalinity by the addition of 0.1
Na2CO3 so that the alkalinity will be at least 25 mg/L as CaCO3. 4.
4. Measure exactly 1 litre of water into each jar. Prepare portions of the
aluminum or ferric sulphate which will yield 10 50 ppm as Al2O3 or
Fe2O3 when added to the sample.
5. Mix at 100 rpm to ensure water is completely mixed
6. Add the chemicals to each reactor near the vortex. All reactors
should be dosed at the same time
7. Rapid mix for 1 minute.
8. Reduce mixing to 60 rpm for 10 minutes; observe the reactors at
minute intervals to detect the formation of flocks.
9. Reduce mixing to 25 rpm for 4 minutes. And reduce to 10 rpm for 2
minutes.
10.Turn off mixers and allow particles to settle for 20 minutes. Measure
the turbidity, color, alkalinity, and pH of the liquid in each jar by
sampling at the top, taking care not to disturb the sediment in
sampling. Measure the depth of sludge in the beaker.
11.Turbidity removal = (initial turbidity-final turbidity)/initial turbidity
12.Draw the graph between final turbidity Vs amount of coagulation
added.

S. No Procedure Jar 1 Jar 2 Jar 3 Jar 4 Jar 5 Jar 6

1 Initial 00 10 20 30 40 50
dose
2 Sample of 1000 1000 1000 1000 1000 1000
water

3 Initial
turbidity
4 Final
turbidity
5 Turbidity
removal

Page | 30
Precautions:

1) Add coagulant dosages simultaneously to all the beakers while stirring

2) Add the dosages at the point where intimate mixing is ensured 3) Range
of optimum pH values should be maintained for optimum utilization of the
coagulation.

The sample graph between final turbidity and amount of coagulant added is
shown below.

Note: RT = Residual Turbidity

Page | 31