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INDEX

Sr Test parameter
1 Acidity as CaCO3
2 Alkalinity (Phenolphthalein and Total)
3 Calcium And Magnesium
4 Chloride
5 Conductivity
6 Nitrogen (Ammoniacal Nitrogen)
7 Nitrogen (Nitrate) (NO3-)
8 Nitrogen (Nitrite) (NO2-)
9 pH
10 Phosphorous (Phosphate)
11 Residual Free Chlorine
12 Silica
13 Sulphate
14 Total Hardness, Calcium & Magnesium
15 TSS / MLSS
16 Turbidity
17 Volatile and Fixed Residue

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Document No 01

Acidity as CaCO3

A) Aim: Determination of Acidity in water sample

B) Normative Reference: IS 3025 (P22): RA

C) Principle: -
Acidity of water is its quantitative capacity to react with a strong base to a designated pH. It
may be defined as equivalent concentration of hydrogen ions in mg/l. The equation in its
simplest form is as follows:
H+ + NaOH = H2O + Na+
D)Apparatus / Equipment:

1. pH Meter: o ~ 6.2
2. Burette: 50-ml capacity.
3. Magnetic Stirring Device.

E) Chemicals / Reagents:

1. Distilled Water: pH should not be less than 6·0. If the pH is less than 6'0, it shall be freshly
boiled for 15 minutes and cooled.
2. Potassium Acid Phthalate: 0·02 N. Dissolve 4·0846 g of potassium acid phthalate salt
(KHC~H404) (dried at 120°C for 2 hours) in carbon dioxide free distilled water and dilute
to 1 litre.
3. Sodium Hydroxide Solution: 15 N.
4. Sodium hydroxide solution: 1 N. Dilute 67 ml of 15 N sodium hydroxide solution to one
litre with distilled water.
5. Sodium hydroxide solution: 0.02· N.
6. Phenolphthalein Indicator: Dissolve 0'5 g of phenolphthalein in 100 ml, 1: 1 (v/v) alcohol
water mixture and add 0.02 N sodium hydroxide solution drop by drop till very faint pink
colour is observed.
7. Methyl Orange Indicator: Dissolve 0·5 g of methyl orange in distilled water and make up
to 100 ml in a volumetric flask.

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F) Procedure:
1) Sampling: The sampling and storage shall be done as is prescribed in IS:3025 Part 1. The
sample bottles should be cleaned thoroughly with Dilute 6N HNO3. Prior to the rinsing
with water. The water sample should be collected in polyethylene bottle or glass
containers.

2) Analysis:

Indicator Method–
Pipette 20 ml or a suitable aliquot of sample into a 100-ml beaker.
1. The sample size shall be so selected so that not more than 20 ml of titrant is needed for
the titration.
2. Determine the pH of water. If pH is less than, 3-7, add two drops of methyl orange
indicator into the first sample beaker and titrate with standard 0·02 N sodium hydroxide
solution until the colour changes to the faint orange characteristic of pH 3.7. Record the
volume of sodium hydroxide used.
3. To the second sample beaker, add 2 to 3 drops of phenolphthalein indicator and titrate
with 0·02 N sodium hydroxide solution to the appearance of faint pink colour
characteristics of pH 8.3. Record the volume used.

G) Calculation:

Calculate acidity in the sample as follows:

Acidity at pH 3.7, as mg/l CaC03 = A x N x 50000/ V

Acidity at pH 8.3, as mg/l CaC03 = B x N x 50000/ V

Where,
A - Volume in ml of standard sodium hydroxide used to titrate to pH 3.7
N - Normality of standard sodium hydroxide,
V - Volume in ml of sample taken for test, and
B - Volume in ml of standard sodium hydroxide used to titrate to pH 8·3.

H) Conclusion:
Prescribes the indicator and potentiometric methods for determination of acidity. These
methods are applicable to the determination of acidity in water and waste water. The
applicable range is 0·5 to 500 mg/t acidity as CaCO 3

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Alkalinity (Phenolphthalein and Total)

A) Aim: Determination of Alkalinity in Water sample

B) Normative Reference: IS 3025 (P23): 1986 RA 2014

C) Principle: -
Alkalinity of water is the capacity of that water to accept protons. It may be defined as the
quantitative capacity of an aqueous medium to react with hydrogen ions to pH 8.3
(phenolphthalein alkalinity) and then to pH 3.7 (Total alkalinity or Methyl Orange alkalinity).
The equation in its simplest form is as follows:
phenolphthalein alkalinity = CO3-- + H+ = HCO3

From pH 8.3 to 3.7, the following reaction may occur

HCO3- + H+ = H2CO3

D) Apparatus and Equipment: -

 Beakers: The size will depend upon the electrode and the size of the sample to be
used for determination of alkalinity.
 Pipettes (volumetric)
 Flasks (volumetric): 1000mL, 200mL, 100mL

E) Chemicals / Reagents: -

1. Standard H2SO4, 0.02 N: Prepare 0.1N H2SO4 by diluting 3mL conc. H2SO4 to 1000mL.
Standardize it against standard 0.1N Na 2CO3 solution. Dilute appropriate volume of
H2SO4 to 1000mL to obtain standard 0.02 H2SO4.
2. Phenolphthalein indicator: Dissolved 0.5g in 500mL 95% ethyl alcohol.
Add 500mL distilled water. Add drop wise 0.02N NaOH till faint pink colour appears (pH
8.3).
3. Methyl orange indicator: Dissolve 0.5g and dilute to 1000mL with CO 2 free distilled
water (pH 4.3-4.5). OR
Bromocresol green indicator: Dissolve 0.1g bromocresol green, sodium salt, in 100mL
distilled water (pH 4.5).
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F) Procedure:
A) Sampling: Sampling and storage shall be done as prescribed in IS 3025 (P1): 1986
‘Methods and sampling and test (Physical and chemical) for water and wastewater: part 1
sampling first revision:

B) Analysis:

1. Take 25 or 50mL sample in a conical flask and add 2-3 drops of phenolphthalein
indicator.
2. If pink color develops titrate with 0.02N H2SO4 till disappears or pH is 8.3.
3. Note the volume of H2SO4 required. Add 2-3 drops of methyl orange to the same flask,
and continue titration till yellow color changes to orange.
4. Note the volumes of H2SO4 required.
5. In case pink color does not appear after addition of phenolphthalein continue titrate
by adding 2-3 drops of methyl orange. Note the volumes of H 2SO4 required.

G) Calculation:

Phenolphthalein alkalinity (mg/L) = (A x N x 50000) / Volume of sample

Total Alkalinity (mg/L) = (A+B) x N x 50000 / Volume of sample

Where, A = ml of standard Sulphuric acid used to titrate to pH 8-3,

B = ml of standard Sulphuric acid used to titrate from pH 8-3 to pH 3-7,
N = normality of acid used, and V = volume in ml of sample taken for test.

Three types of alkalinities, i.e., hydroxide, carbonate and bicarbonate are easily calculated from
the table given as under:

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Once carbonate and bicarbonate alkalinities are known, then their conversions to milligrams CO3
– or HCO3 - /L are possible.

mg CO3 --/L = Carbonate alkalinity mg CaCO3/L x 0.6 mg HCO3 = Bicarbonate alkalinity mg CaCO3/L
x 1.22 from above, molar concentration may be obtained as follows:

[CO3 --] = mg/L CO3 / 60000 [HCO3 -] = mg/L HCO3 - / 61000

H) Conclusion:

Alkalinity of water is its capacity to neutralize a strong acid and it is normally due to the presence
of bicarbonate, carbonate and hydroxide compound of calcium, sodium and potassium.

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Calcium And Magnesium

A) Aim: Determination of Calcium and magnesium in water sample

B) Normative Method: Ca: IS 3025 (P40): 1991 RA / Mg: IS 3025 (P46): 1994 RA 2014

C) Principle:
In a solution containing both calcium and magnesium, calcium can be determined directly
with EDTA when the pH is made sufficiently high (12 to 13) so that the magnesium is largely
precipitated as the hydroxide and an indicator is used which combines only with calcium.

D) Apparatus / Equipment:
 Burette 10-ml, 25-ml class A
 Conical flask 250-ml capacity
 Measuring cylinder 50-ml capacity

E) Chemicals /Reagents:

 Standard EDTA 0.01(M): 3.723 gm of disodium salt of EDTA is dissolved in 1000ml DW.
 Sodium Hydroxide Solution: 1 N
 Indicator: Murexide / PNR Indicator.

F) Procedure:

1)Sampling: Collect the laboratory sample in a polythene bottle completely filled and tightly
stoppered.

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2) Analysis:
 Take 50 ml Water Sample into a conical flask.
 Add 2.0 ml Sodium hydroxide solution.
 Add 0.1-to-0.2-gram murexide indicator.
 Titrate the given sample solution to EDTA with continuously stirring to the proper end
point.
 End point: pink to purple colour

F) Calculation:

Calcium Hardness as MgCaCO3 / L = V2 x B x 100 x 1000 / ml of sample

Where, V2 = mL titration for sample in determination of Total hardness and

B = mg CaCO3 equivalent to 1.00 mL EDTA titrant.

Calcium (mg/L) = V2 X B X 40 X 1000 / ml of sample

Where,
V2 = mL titration for sample in determination of Total hardness and
B= mg CaCO3 equivalent to 1 ml EDTA titrant

Magnesium(mg/L) is estimated from the difference between Hardness and Calcium as CaCO 3 and
applying atomic mass factor for Mg

Mg (mg/L) = [Total Hardness (as mg CaCO3 / L) – Calcium Hardness (as mg CaCO3 /L)] x 0.243.

G) Conclusion:
We conclude that more filtered and cleaned water will be softer and will contain the least
amount of Ca+2 and Mg+2 ions were correct.

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Chloride

A) Aim: Determination of Chloride in water sample

B) Normative Reference: IS 3025 (P32): 1988 RA 2014

C) Principle:
In a neutral or slightly alkaline solution, potassium chromate can indicate the end point of
the silver nitrate titration of chloride. Silver chloride is precipitated before red silver
chromate is formed.

D) Apparatus/Equipment:
 Burette 10-ml and 25-ml (Class A).
 Conical flask 250-ml capacity
 Measuring cylinder 50-ml capacity
 Titration assembly

E) Chemicals / Reagent:

1. Potassium Chromate indicator solution (0.5 %)

Dissolve 50gm K2CrO4in little D/W Add AgNO 3 solution until a definite red ppt is formed.
Let stand for 12 hrs. filter& dilute to 1 lit. with D/W.
2. Standard silver nitrate solution 0.0141 M: - Dissolve 2.395 gm AgNO3 in D/W & dilute to 1 lit.
Standardize against NaCl
3. Standard silver nitrate solution 0.1 M: - Dissolve 2.395 gm AgNO3 in D/W & dilute to 1 lit.
Standardize against NaCl
4. Coagulating agent: 1 % Aluminium Hydroxide aqueous solution.

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5. 1 N H2SO4: Carefully and slowly Add 27.8 ml of concentrated Sulphuric acid in 500-ml water.
Allow to cool and further dilute the solution to 1 L with distilled water.

F) Procedure: -

A) Sampling: Collect the laboratory sample in a polythene bottle completely filled and tightly
stoppered.

B) Analysis: Use 100 ml sample or suitable portion diluted to 100 ml. If sample is highly colored,
add 3 ml Al (OH)3 suspension, mix. Let the precipitation settle & filter.

Directly titrate the samples in pH range 7-10. Adjust sample pH 7-10 with 1 N H 2SO4 or 1 N
NaOH. Add 1 ml Potassium chromate indicator. Titrate with std. silver nitrate solution to
pinkish yellow end point. Perform blank using same procedure.

G) Calculation:

Chloride as Cl– (mg/L) = (A-B) x N x 35450 / ml of Sample

Where, A = ml of Silver Nitrate used for blank.

B = ml of silver nitrate used for sample.
N = normality of AgNO3 solution

H) Conclusion:

Chloride is one of the major organic anions in water and wastewater. In Potable water salty
taste produced by chloride concentrations is variable and dependent on the chemical
composition. Chloride concentration is higher in wastewater than in raw water. A high
chloride content may harm metallic pipes and structure as well as growing plant.

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Conductivity

A) Aim: Determination of Conductivity of Water sample

B) Normative Reference: IS 3025 (P14): 1984 RA 2013

C) Principle:
Conductivity, k, is a measure of the ability of an aqueous solution to carry an electric
current. This ability depends on the presence of ions; on their total concentration, mobility,
and valence; and on the temperature of measurement.
D) Apparatus/ Equipment:
Conductivity meter with temperature compensation facility.
E) Chemicals / Reagents:
Distilled water
Certified conductivity solutions of KCl 0.001M, 0.01M and 0.1 M
F) Procedure:
1) Sampling: Collect the laboratory sample in a polythene bottle completely filled and tightly
stoppered. Biological activity can be reduced by storing the samples in the dark at 4 oC.
However, sample shall be brought to equilibrium at the reference temperature of 25 oC
before the conductivity is measured.
2) Analysis:
a) Standardize the Conductivity meter with standard (N/10), (N/100) & (N/1000) KCl solutions.
Rinse the Conductivity cell by distilled water and clean with soft tissue paper. Then dip into
standard (N/10), (N/100) and (N/1000) KCl solutions and the reading should match with the
following theoretical values in respect of specified temperature.
0.001 (M) KCl = 146.9 µs
0.01 (M) KCl = 1412 µs
0.1 (M) KCl = 12890 µs
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b) Rinse the Conductivity cell by distilled water and clean with soft tissue paper. Then dip in
the sample at room temperature or at temperature as per customer's requirement and
take the reading from conductivity meter and express the specific conductance as
µmhos/cm.
F) Calculation:
Direct from Display, Report conductivity along with temperature.
G) Conclusion:
The purpose of this experiment was to determine the effect of increasing the
concentration of an ionic compound in an aqueous solution on conductivity. This purpose
was achieved by measuring conductivity of different solutions using conductivity probe.

Nitrogen (Ammoniacal Nitrogen)

A) Aim: Determination of Ammoniacal Nitrogen in water sample.

B) Normative Reference: IS 3025 (P34): 1988 RA 2014

C) Principle:
An intensely blue compound indophenol is formed by the reaction of ammonia,
hypochlorite and phenol catalyzed by a manganous salt.

D) Apparatus/ Equipment:
 Spectrophotometer or filter photometer for use at 630 nm. The light path of these
photometers should be 1 cm.
 Magnetic stirrer.

E) Chemicals/ Reagents:
 Ammonia-free water
 Hypochlorous acid reagent: Add to 40 ml of water, 10 ml of 5 percent solution of
sodium hypochlorite prepared. Adjust pH to 6.5 to 7.0 with hydrochloric acid.
 Manganese sulphate solution: 0.006 N. Dissolve 50 mg of manganous sulphate
monohydrate in 100 ml of water.
 Phenol solution: take 11.1 ml of phenol (Liquefied) and dissolve in 100ml of ethyl alcohol
(Prepare weekly). Since phenol is corrosive, handle with care.
 Stock ammonium solution: Dissolve 381.9 mg of anhydrous ammonium chloride in
water and dilute to 1 000 ml (1.00 ml = 122 µg as NH3 or 100 µg as N).
 Standard ammonia solution L: Dilute 5’00 ml of stock solution to 1 000 ml with water
(1.00 ml = 0.500 µg of nitrogen or 0.607 µg of ammonia).

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F) Procedure:
1) Sampling: The sampling shall be done as prescribed in IS: 3025(Part 1) 1986.The sampling
bottles shall be cleaned thoroughly with dilute 6N HNO3, prior to the final rinsing with
water. The water sample should be collected and stored preferably in polypropylene
bottles or chemically 0.45 mm membrane filter, at the time of sampling is required. The
analysis of such sample is carried out within 24 hrs. Of sampling.
2) Analysis:
 To a 10.0 ml of sample in a 50 ml beaker, add 1 drop of manganous sulphate solution
 Stir on a magnetic stirrer and add 0.5 ml of hypochlorous acid reagent.
 Immediately add a drop at a time, 0.6 ml of phenate reagent.
 Add reagent without delay using a bulb pipette or burette for convenient delivery. Mark
pipette for hypochlorous acid at the 0.5 ml level and deliver the phenate reagent from a
pipette or burette that has been calibrated by counting the drops previously found to be
equivalent to 0.6 ml.

 Stir vigorously during addition of reagents. Carry a blank and a standard through the
procedure with each batch of samples.

 Measure absorbance using reagent blank to zero in the spectrophotometer. (Colour

formation is complete in 10 minutes and is stable for at least 24 hours).

 Measure the blue colour at 630 nm, satisfactory measurements can be made in 600 to 660
nm region.

G) Calculation: -
Concentration from calibration curve x Dilution factor x Sample makeup volume / Sample
volume.

H) Conclusion:
Ammonia is produced by the microbiological degradation of organic nitrogenous matter. It
appears, therefore, in many ground waters as well as surface waters. Concentrations of
ammonia above a certain level in water polluted either due to sewage or industrial waste is
toxic to fish. The proportions of the two forms of ammonia nitrogen in surface water
depend on pH.

pH 6 7 8 9 10 11
%NH3 0 1 4 25 78 96
%NH4 100 99 96 75 22 4

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For accurate results, it is generally preferable to distill off ammonia from the sample, and
absorb in boric acid. It is then determined either by titration or colorimetrically using
Nessler reagent. Direct nesslerisation of the sample is quicker depending upon
interference.

Nitrogen (Nitrate) (NO3-)

-
A) Aim: Determination of Nitrogen (Nitrate) (NO3 ) in water sample.

B) Normative Reference: IS 3025 (P34): 1988 RA 2014

C) Principle:
Two moles of nitrate nitrogen react with one mole of chromo tropic acid to form a yellow
reaction product having maximum absorbance at 410 nm

D) Apparatus and equipment:

1. Spectrophotometer: at 410 nm with light path of 1cm or longer.

E) Chemicals / Reagents:

1. Nitrate free water: The absorbance of a reagent blank prepared with this water should
not exceed 0.01. Use for all solutions and dilution.
2. Sulphite urea reagent: Dissolve 5 gram of urea and 4 gram of anhydrous sodium sulphite
in water and dilute to 1000 ml
3. Antimony reagent: Dissolve 500 mg antimony metal by heating in 80 ml concentrated
sulphuric acid. Cool and cautiously add to 20 ml of iced cold water. If crystals form upon
standing overnight, redissolved by heating.
4. Chromotropic acid solution: Dissolve 100 mg of purified chromotropic acid crystal in 100
ml of concentrated sulphuric acid and store in brown bottle. Prepare every two 2 weeks.
A colorless reagent solution signifies the absence of nitrate contamination from sulphuric
acid.
5. Stock nitrate solution: Dissolve 0.7218-gram anhydrous potassium nitrate and dilute to

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1000ml with distilled water.

6. Standard nitrate solution: Dilute 50 mL stock nitrate solution to 500 mL with distilled
water. 1mL = 10µg NO3N = 44.3µgNO3.

F) Procedure:
1) Sampling: The sampling shall be done as prescribed in IS 3025 (P1): 1986. The sampling
bottles shall be cleaned thoroughly with dilute 6N HNO3, prior to the final rinsing with
water. The water sample should be collected and stored preferably in polypropylene
bottles or chemically 0.45 mm membrane filter, at the time of sampling is required. The
analysis of such sample is carried out within 24 hrs. of sampling.

2) Procedure:

 Take 2 ml sample in 10 ml volumetric flask.

 Add 1 drop of sulfite urea reagent. Place the flask in tray of cold water.
 Add 2 ml antimony reagent. After 4 min in the bath add 1 ml of chromotropic acid
reagent, swirl and make up with sulphuric acid. Wait for 30 min.
 Measure the absorbance at 410 nm.

G) Calculation:

Nitrate N, mg/L = µg of nitrate nitrogen in 10 ml final volume / Vol. of sample taken (2 ml)

H) Conclusion:
Together with phosphorus, nitrates in excess amounts can accelerate eutrophication,
causing dramatic increases in aquatic plant growth and changes in the types of plants and
animals that live in the stream.

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Nitrogen (Nitrite) (NO2-)

A) Aim: Determination of Nitrite in water sample.

B) Normative Reference: IS 3025 (P34): 1988 RA 2014

C) Principle:
-
Nitrite (NO2 ) is determined through formation of a reddish-purple azodye at pH 2.0-2.5 by
coupling diazotized Sulphanilamide with N-(1-Naphthyl) ethylenediamine dihydrochloride
(NED- dihydrochloride). The method is applicable to 1µg NO2- N/L. The colour system obeys
Beer’s law up to 180µg N/L with 1cm light path at 543nm. The chemical reaction involved in
the method is given below:

D) Apparatus / Equipment:

1. Colorimeter or spectra-photometer that can be operated at543 nm.

2. Nessler tubes or 100mL capacity volumetric flask.

E) Chemicals / Reagents:

1. Nitrate free water: The absorbance of a reagent blank prepared with this water should
not exceed 0.01. use for all solutions and dilution.

2. Sulphanilamide reagent: Dissolve 5-gram Sulphanilamide in a mixture of 50 ml conc. HCL

and 300 ml Water. Dilute to 500 ml with water. The reagent is stable foe one months.

3. N-(1naphthyl) Ethylenediaminedihydrochloride solution: Dissolve 500 mg of N-

( 1naphthyl) Ethylenediaminedihydrochloride in 500 ml water. Store in dark colored
bottle.

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4. Sodium oxalate (0.05N): Dissolve 3.35g Na2C2O4 in water dilute to 1000mL.

5. Stock nitrite solution: Dissolve 1.2320 sodium nitrite (NaNO 2) in water and dilute to
1000mL; 1mL = 250µg N.

6. Standard nitrite solution: Dilute appropriate aliquot of stock nitrite solution to 1000mL
with distilled water so that 1mL = 0.5 µg N in the solution.

F) Procedure:

1) Sampling: The sampling shall be done as prescribed in IS 3025 (P1): 1986. The sampling
bottles shall be cleaned thoroughly with dilute 6N HNO3, prior to the final rinsing with
water. The water sample should be collected and stored preferably in polypropylene
bottles or chemically 0.45 mm membrane filter, at the time of sampling is required. The
analysis of such sample is carried out within 24 hrs. of sampling.

2) Analysis:

1. If sample contains suspended solids, filter through a 0.45 mm pore diameter membrane
filter.
2. To 50mL clear sample neutralized to pH 7 or to a portion diluted to 50mL, add 1mL
sulfanilamide solution. Let reagent react for 2 to 8min.
3. Add 1.0mL NED dihydrochloride solution and mix immediately. Measure absorbance after
10 min but before 2 h at 543nm.
4. Prepare blank in the same way substituting water for the sample.

E) Calculation:

Nitrite nitrogen (as NO2-N) / litre = µg N NO2-N / ml of Volume

F) Conclusion:

Nitrite in high levels is toxic to aquatic organisms and usually indicate contamination from
fertilizer run-off. Nitrites can be extremely toxic to fish and other aquatic organisms.

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pH
A) Aim: Determination of pH value of water sample.

B) Normative Reference: IS 3025(P11): 1983 RA 2017

C) Principle:
At a given temperature the intensity of the acidic or basic character of a solution is
indicated by pH or hydrogen ion activity. Alkalinity and acidity are the acid- and base-
neutralizing capacities of a water and usually are expressed as milligrams CaCO3 per liter.

D) Apparatus and Equipment:

1. pH Meter: With glass and reference electrode
2. Magnetic stirrer: With polytetrafluorethylene coated stirring bar
3. Thermometer: With least count of 0.5 deg C

E) Chemical /Reagents:
1. Standard buffer solutions: - Certified buffer solutions pH 4.0, pH 7.0, pH 9.2.

F) Procedure:
1) Sampling: Sample should be analyzed as soon as possible, preferably in the field at the
time of sampling.

2) Analysis: Standardize pH meter with appropriate buffers at 25 deg C.

1. Rinse the glass electrode with distilled water and gently wipe it with a soft filter paper.
2. The determination may now be made by pH meter with glass electrode at 25 deg C or at
temperature as per customer's requirement after.
3. Care must be taken during handling electrode that bulb shall not strike the surface of
container. It may damage the surface of bulb.

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G) Calculation:
Read pH directly from instrument and report to the second decimal place.

H) Conclusion:
1. The pH of that buffer solution which matches with that of the sample to the nearest to
0.1 unit.
2. pH meter is more useful than the other pH indicators because it gives more accurate
reading to determine the acidic and basic nature of sample.

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Phosphorous (Phosphate)

A) Aim: Determination of Phosphorous in water sample.

B) Normative Reference: IS 3025 (P31): RA

C) Principle:
The molybdo-phosphoric acid formed is reduced to an intensely colored complex
molybdenum blue by stannous chloride. This method is significantly sensitive and the
reliability of the method increases at concentrations below 0.1 mg/l of phosphorus with
minimum interference.

D) Apparatus / Equipment:

Spectrophotometer: path of 1 to 10 cm. Suitable for use at 690 nm for aqueous solution,
provided with a light

E) Chemicals / Reagents:

 Phenolphthalein indicator solution

 Strong acid solution: Add slowly 300 ml of Sulphuric acid to about 600 ml of distilled water
cool and add 4 ml of nitric acid and dilute to 1 litre.
 Ammonium molybdate reagent: Dissolve 25 g of ammonium molybdate (NH4)6 Mo 7O24.4
H20 in 175 ml of distilled water. Continuously add 280 ml of concentrated Sulphuric acid to
400 ml of distilled water in a separate beaker, cool and add the molybdate solution to this
acid solution and dilute to 1 litre.
 Standard phosphate solution: Dissolve 219.5 mg of anhydrous potassium dihydrogen
phosphate (KH2PO4) and dilute to 1 litre. 1 ml = 50 µg orthophosphate phosphorus.
 Stannous chloride solution: Dissolve 2.5 g of a fresh stannous chloride
(SnCl2,.2H2O) in 100 ml of glycerol. Heat in a water bath and stir with a glass rod to hasten
dissolution. This reagent is stable and requires neither preservatives nor special storage.
 Activated carbon: Analytical grade, free from phosphates.

F) Procedure:
A) Sampling: Sampling and sample preservation shall be done as prescribed as IS 3025 (P1):
1986 RA

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B) Analysis:
 If colored, decolorize the sample by shaking about 200 ml sample with 256 mg of activated
carbon in an Erlenmeyer flask for 5 minutes. Filter the solution through filter paper
(Whatman No. 42 or equivalent) to remove carbon.
 Take 100 ml of clear and colorless sample containing not more than 0.2 mg of phosphorus,
and add 1 drop of phenolphthalein indicator. If pink colour develops, discharge the color
with strong acid solution.
 If the acid requirement exceeds 5 drops, take a smaller sample and dilute to 100 ml with
distilled water, after first discharging the pink colour with acid.
 Add, with thorough mixing after each addition, 4.0 ml of molybdate reagent and 0.5 ml of
stannous chloride reagent.
 The range of colour development and the intensity of colour are dependent on the
temperature of the final solution.
 The increase in colour for each degree rise in temperature is about one percent. Hence
samples, standards and reagents should be within 2°C of one another at a temperature
between 20 and 30°C. (Take readings after 10 min but before 12 min.)
 Measure the colour spectrophotometrically at 690 nm and compare with calibration curve
using distilled water.
 Always run a blank on the reagents and distilled water. in as much as the colour at first
develops progressively and later fades, it is essential to maintain equal timing conditions
for samples as well as for standards. Standards should be prepared with each set of
samples.
 Read phosphate concentration, from a calibration curve prepared by taking known
phosphate standards and following the same procedural steps as the sample.

G) Calculation:
Phosphorus, mg/l = mg of phosphorus corresponding to control standard x 1000
Volume in ml of sample

H) Conclusion:

In most of the surface waters, availability of phosphorus limits the growth of algae and
macrophytes. The discharge of P-loads contained in waste waters therefore normally results
in an increased growth of algae and macrophytes which may cause reduced water quality by
eutrophication.

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Residual Free Chlorine

A) Aim: Determination of Residual Free Chlorine in water sample.

B) Normative Reference: IS 3025 (P26): 1986 RA 2014

C) Principle:
Chlorine will liberate free iodine from Potassium Iodide solutions at pH – 8 or less. The
liberated iodine is titrated with a standard solution of Sodium thiosulfate, with starch as
indicator.

D) Apparatus /Equipment’s:

 Titration assembly
 Normal laboratory glassware

E) Chemical /Reagent:
1. Acetic acid (glacial)
2. Potassium Iodide; KI, crystal.
3. Standard Na2S2O3 solution-0.1 N
Dissolve 24.82 gm Na2S2O3, 5H2O in 1 lit freshly prepared distilled water. Standardize
against K2Cr2O7
4. From this stock of 0.1 N soln. Prepare 0.01 N & 0.025 N Na 2S2O3 solution.
5. Starch indicator solution-Add 5gm starch pour into 1L of boiling distilled water, stir, and
let settle overnight. Use clear supernatant.
6. Standard Iodine 0.1 N

F) Procedure:
A) Sampling: Chlorine is not stable in aqueous solution. Exposure to sunlight or other light or
agitation will accelerate the reduction of chlorine. Therefore, it is recommended that chlorine
determinations be started immediately after sampling and exposure to light and agitation to
be avoided. The sample cannot be stored. Sampling and storage shall be done as prescribed in
IS 3025 (P1): 1986, Methods of sampling and test for water and waste water.

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A) Analysis:
1. Select appropriate amount of sample (100 ml).
2. Add 5 ml of Acetic acid or enough to reduce the pH between 3.0 & 4.0 in a flask.
Add 1 gm KI. Titrate with 0.01 N or 0.025 N thiosulfate solution. until yellow color of the
liberated Iodine is almost discharged.
3. Add 1-ml starch solution and titrate until the blue color is discharged.
4. In case of residual chlorine is very low, add starch solution before starting up the
titration.

Blank titration:
1. Correct the result of the sample titration by determining the reagent blank (Distilled
water corresponding to sample volume used) contributed by such reagent impurities.

G) Calculation:

For the determination of total available residual chlorine in a water sample

mg cl or Cl2/L = (A±B) x N x 35.45 / ml sample

Where,
A = ml titration for sample
B = ml titration for blank (positive or negative)
N= normality of Na2S2O3

H) Conclusion:
Water is routinely chlorinated to make it microbiologically safe. When chlorine is added to
water other than distilled water, initially a small amount reacts with impurities in the water
and does not show as residual chlorine. This is called the chlorine demand of the water, which
has no germicidal effect. Chlorine added subsequently remains as the residual chlorine (free
available and combined available chlorine), which is important for disinfection. The residual
chlorine levels of water used for different purposes have been specified

Silica
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A) Aim: Determination of Silica in water sample

B) Normative Reference: IS 3025 (P35): RA

C) Principle:
Ammonium molybdate at pH about 1.2 reacts with silica and any phosphate present to
produce heteropoly acids, Oxalic acid is added to destroy molybdophosphoric acid. Even if
phosphate is known to be absent, the addition of oxalic acid is must in this method. The
intensity of yellow colour produced is proportional to concentration of molybdate reactive
silica. In at least one of its forms, silica does not react with molybdate even though it is
capable 0) passing through the filter paper and not noticeably turbid. It is not known to what
extent such un-reactive silica occurs in waters, Molybdate unreactive silica can be converted
into molybdate reactive form by heating or fusing with alkali.

D) Apparatus/ Equipment:

 Platinum dishes: 100 ml capacity.

 Spectrophotometer: for use at 410 nm,
 Nessler tubes: matched, 50 mi

E) Chemicals / Reagents:

1. Sodium bicarbonate
2. Sulphuric acid - 1 N
3. Hydrochloric acid - 1: 1.
4. Ammonium Molybdate reagent: Dissolve 10 g ammonium molybdate [(NH4)
6Mo7024,4H20] in distilled water with stirring and gentle warming, and dilute to 100 ml.
Filter, if necessary. Adjust to pH 7 to 8 with silica free ammonia or sodium hydroxide and
store in polyethylene bottle to stabilize.
5. Oxalic acid solution: Dissolve 7.5 g of oxalic acid in distilled water and dilute to 100 ml
6. Stock silica solution: Dissolve 4.73 g of sodium metasilicatenonahydrate (Na2Si03.9H20) in
distilled water and dilute to 1000 ml. Store in plastic bottle.
7. Standard silica solution - Dilute 10.00 ml of stock solution to 1000 ml with distilled water.
1.00 ml = 10.0 (.ug of SiO2)

8. Permanent colour solutions as follows any one:

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A) Potassium chromate solution - Dissolve 630 mg of potassium chromate in distilled water

and dilute to 1 litre,
B) Borax solution - Dissolve 10 g of sodium borate decahydrate in distilled water and dilute
to 1 litre.

F) Procedure: -
1) Sampling: The sampling and storage shall be done as is prescribed in IS 3025 (P1). The
sample bottles should be cleaned thoroughly with Dilute 6N HNO3. Prior to the rinsing
with water. The water sample should be collected in polyethylene bottle or glass
containers.

2) Analysis:

Colour development-
1. To 50 ml of sample, add in quick succession in 100 ml volumetric flask.
2. Add 1.0 ml of 1: 1 hydrochloric acid and 2.0 ml ammonium molybdate reagent Mix by
inverting at least six times and let stand for 5 to 10 minutes.
3. Add 2.0 ml of oxalic acid solution and mix well. Read colour after 2 minutes but before 15
minutes, measuring time from addition of oxalic acid. Make up the volume with distilled
water. Measure colour in a spectrophotometer or visually.

To detect the presence of molybdate unreactive silica, digest sample with sodium bicarbonate
before colour development. This digestion may not be sufficient to convert all molybdate
unreactive silica to the molybdate-reactive form. Complex silicates and higher silica polymers
require extended fusion with alkali at higher temperature or digestion under pressure for
complete conversion Omit digestion, if all the silica is known to react with molybdate. Prepare
a clear sample by filtration, if necessary. Place 50·0 ml or smaller portion diluted to 50 ml in a
100 ml platinum dish. Add 200 mg of silica-free sodium bicarbonate and digest on steam bath
for 1 h. Cool and add slowly, 2.4 ml of 1N Sulphuric acid with stirring. Do not interrupt analysis
but proceed at once with remaining steps. Transfer quantitatively to a 50 ml Nessler tube and
make up to mark with distilled water.

Sulphate
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A) Aim: Determination of Sulphate in Water sample

B) Normative Reference: IS 3025 (P24): 1986 RA 2014

C) Principle:
Sulphate ion is precipitated in Hydrochloric acid medium with barium chloride in such a
manner as to form barium sulphate crystals of uniform size. The absorbance of barium
sulphate suspension is measured by a nephelometer or turbidity meter and the sulphate
ion concentration is determined by comparison of the reading with a standard curve.

D)Apparatus /Equipment:
 UV-Spectrophotometer
 Normal laboratory glassware

E) Chemicals/ Reagents:
A) Barium Chloride Crystal
B) Conditioning reagent: Mix 50 ml glycerol with a solution containing 30 ml Conc.HCl, 300
ml Distilled water,100 ml 95% ethyl or isopropyl alcohol and 75-gram sodium chloride.
C) Hydrochloric acid: Dissolve one volume of Concentrated HCl with 9 volume of distilled
water.

F) Procedure:
A) Sampling: Sampling and storage shall be done as prescribed in IS3025 (P1): 1986, Methods
of sampling and test (physical and chemical) for water and waste water Part 1 Sampling
first revision:
B) Highly polluted or contaminated samples should be stored at low temp. or treated with
formaldehyde, sulphite may be oxidized to sulphate by dissolved oxygen above pH 8.00,
samples containing sulphite should have their pH adjusted below this value.
C) Analysis:
 Take 20 ml clear aliquot of the water sample or suitable amount diluted to 20 ml in 100
ml conical flask.
 Add 1 ml HCl and 1 ml conditioning reagent and mix well for 30 secs.
 Read absorbance on spectrophotometer after 10 min.

G) Calculation:

mg/L SO42- = Concentration from calibration curve x 100 x dilution factor / Sample volume

Total Hardness, Calcium & Magnesium

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A) Aim: Determination of Total hardness in water sample

B) Normative Method: IS 3025 (P21), (40), (46): RA

C) Principle:
EDTA forms a chelated soluble complex when added to a solution of certain metal cations. If a
small amount of a dye such as Eriochrome Black T or calmagite is added to an aqueous
solution containing calcium and magnesium ions at a pH of 10.0 ± 0.1, the solution becomes
wine red. If EDTA is added as a titrant, the calcium and magnesium will be complexed which is
detected by color change of indicator from wine red to blue, marking the end point of the
titration. At sufficiently higher pH EDTA is added to water containing both Calcium and
Magnesium, it combines first with Calcium. At higher pH in 12.0-13.0 Mg 2+ ion is largely
precipitated as Magnesium Hydroxide and only Ca 2+ ion is estimated using murexide indicator
against EDTA solution. Magnesium is estimated from the difference between Hardness and
Calcium as CaCO3 and applying atomic mass factor for Mg

D) Apparatus / Equipments:
 Burette 10-ml, 25-ml class A
 Conical flask 250-ml capacity
 Measuring cylinder 50-ml capacity

E) Chemicals /Reagents:
 Standard EDTA 0.01(M): 3.723 gm of disodium salt of EDTA is dissolved in 1000ml DW.
 Buffer Solution: Dissolve 16.9g ammonium chloride (NH 4Cl) in 143 mL conc. ammonium
hydroxide (NH4OH) Add 1.25 g magnesium salt of EDTA (available commercially) and dilute
to 250 ml with distilled water.
 Indicator: Eriochrome Black T

F) Procedure:
1) Sampling: Collect the laboratory sample in a polythene bottle completely filled and tightly
stoppered.
2) Analysis: Pretreatment of polluted water and wastewater samples: Use nitric acid-sulfuric acid
or nitric acid-perchloric acid digestion procedure to remove coloring organic interference.
Complexing agents: For most waters no complexing agent is needed. Occasionally water
containing interfering ions requires adding an appropriate complexing agent to give a clear,
sharp change in color at the end point. The following are satisfactory:

 Inhibitor I: Adjust acid samples to pH- 6 or higher with buffer or 0.1N NaOH. Add 250 mg
sodium (NaCN) in powder form. Add sufficient buffer to adjust to pH 10.0
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 Inhibitor II: Dissolve 5.0 g sodium sulfide nonahydrate (Na 2S 9H2O) or 3.7 g Na2S. 5H2O in
100 mL distilled water. Exclude air with a tightly fitting rubber stopper. This inhibitor
deteriorates through air oxidation. It produces a sulfide precipitate that obscures the end
point when appreciable concentrations of heavy metals are present.

Titration for Total Hardness:

1. Take 50 mL of sample in a conical flask.

2. Adjust the pH of sample to 10.0 to 10.1 by adding 2 mL of buffer solution.
3. Then add an appropriate amount of dry powder of Eriochrome Black T indicator.
4. Titrate against standard 0.01M EDTA titrant slowly.
5. End point will be wine red to blue colour.
6. Note down burette reading V1-ml
7. If burette reading is more than full burette, a less sample or sample with appropriate
dilution may be use for titration.

F) Calculation:

Total Hardness (EDTA) as mg CaCO3/L = V x N x 1000 / mL sample

Where, V = Volume in ml of the EDTA Standard Solution used in the titration for the sample.
B = mg CaCO3 equivalent to 1.00 mL EDTA titrant.

 Carbonate Hardness and Non-Carbonate Hardness:

Determine Total Alkalinity As per IS 3025(Part 23) Carbonate and Non-Carbonate Hardness as
calculate as follows:

a) Carbonate Hardness:
 When total hardness is greater than total alkalinity, carbonate hardness is equal to total
alkalinity
 When total hardness is equal to total alkalinity, carbonate hardness is equal to total
hardness

b) Non-Carbonate Hardness:
 Non carbonate hardness =total hardness – total alkalinity

G) Conclusion:
We conclude that more filtered and cleaned water will be softer and will contain the least
amount of Ca+2 and Mg+2 ions were correct.
TSS / MLSS

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A) Aim: Determination of Total Suspended Solid in water sample

B) Normative Reference: IS 3025 (P17): 1984 RA 2017

C) Principle:
Non filterable residue is determined by passing the sample through a weighed filter and
drying the filter at 103-105 Deg. C. Non filterable residue is calculated from the increase in
mass of the filter.

D) Apparatus / Equipment:
 Distilled Water
 Filter paper 0.45 mic x 47 mm diameter.
 Filtration suction assembly
 Drying oven: For operation at 105OC

E) Procedure:
1) Sampling: Collect the laboratory sample in a polythene bottle completely filled and tightly
stoppered.
2) Analysis:
 Mix the sample thoroughly, Measure 25 ml or 50 ml sample depending upon the nature of
the sample.
 Filter through a previously dried and weighed 0.45 mic membrane
 Keep the filter paper in an oven at 103-105 OC for at least 1 hr. Cool in desiccators and weigh
to a constant weight.

F) Calculation:

For TSS / MLSS (mg/L) = (A-B) x 1000 x1000 / ml of sample

Where, A= Final weight of Filter Paper (g)

B= Initial weight of Filter Paper (g)

G) Conclusion:
we can conclude that TSS as all particles suspended in water which will not pass
through a filter. If the levels of TSS in the water increases, a water begins to lose its ability
to support a diversity of aquatic life. This is because suspended solids absorb heat from
sunlight which increases water temperature and subsequently decreases levels of
dissolved oxygen.
Turbidity

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A) Aim: Determination of Turbidity in water sample

B) Normative Reference: IS 3025 (P10): 1984 RA 2017

C) Principle:
Turbidity measurement is on scattering of light by the suspended particles in sample.
D) Apparatus/ Equipment:
 Nepheloturbidity meter/Turbidity meter
 The sample tubes should be clean and colour less glass.
E) Chemicals / Reagents:
Certified reference turbidity suspension. 1000 NTU (Formazin solution)
F) Procedure:
1) Sampling: Preservation of sample is not practical. Analysis should begin as soon as possible.
Refrigeration at 4oC is recommended to minimize microbiological reaction.
2) Analysis:
1. Allow sufficient warm up period after switching ON the instrument.
2. Calibrate the instrument as per instruction specified in instrument manual. Use appropriate
standards so as to cover entire range of the instrument.
3. Adjust the display to 000 by taking distilled water as blank in sample cuvette.
4. Calibrate instrument by placing standard in sample cuvette.
5. Again, check the display zero with the test tube containing distilled water.
6. Now the instrument is ready to take measurement of any unknown suspension.
F) Calculation: Report turbidity reading as follows;
Turbidity Range NTU Report to the nearest NTU
0 –1.0 0.1
1 – 10 0.5
10 – 40 1
40 – 100 5
100 – 400 10
400 – 1000 100
G) Conclusion:
Turbidity is important because it affects both the acceptability of water to consumers, and the
selection and efficiency of treatment processes, particularly the efficiency of disinfection with
chlorine since it exerts a chlorine demand and protects microorganisms and may also
stimulate the growth of bacteria.

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Volatile and Fixed Residue

A) Aim: Determination of Volatile and Fixed Residue (Total Filterable & Non-Filterable)

B) Normative Reference: IS 3025 (P18): 1984 RA 2002

C) Principle:
Prescribes a gravimetric method for the determination of volatile and fixed portions of total,
filterable and non-filterable residues. The method is applicable to all types of water and waste
water.

D) Apparatus / Equipment:
 Evaporating Dish: 90 mm, 100 ml capacity made of platinum, porcelain, silica or
borosilicate glass
 Steam Bath:
 Drying Oven: With thermostatic control for maintaining temperature up to 180 ±2°C.
 Dessicator:
 Muffle Furnace: Capable Of operation at 550°C.
 Analytical Balance: of 200 g capacity and capable of weighing to nearest 0.1 mg.

E) Procedure: -
1) Sampling: Preservation is not practical. Refrigeration or chilling to 4°C is recommended.
2) Analysis:
1. Heat the clean evaporating dish to 180°C for 1 hour. Cool, desiccate, weigh and store in
desiccator until ready for use.
2. Select volume of the sample which has residue between 25 and 250 mg, preferably
between 100 and 200 mg. This volume may be estimated from values of specific
conductance. To obtain a measurable residue, successive aliquots of sample may be added
to the sample dish.
3. Pipette this volume in a weighed evaporating dish on steam-bath. Evaporation may also be
performed in a drying oven. The temperature shall be lowered to approximately 98°Cto
prevent boiling and splattering of the sample. After complete evaporation of water from
the residue, transfer the dish to an oven at 103-105°C or 179-181°C and dry to constant mass,
that is, till the difference in the successive weighing is less than 0.5 mg. Drying for a long
duration (usually 1 to 2 hours) is done to eliminate necessity of checking for constant mass.
The time for drying is constant mass with a given type of sample when a number of
samples of nearly same type are to be analyzed, has to be determined by trial.

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4. Weigh the dish as soon as it has cooled avoiding residue to stay for long time as some
residues are hygroscopic and may absorb water from desiccant that is absolutely dry. After
weighing, ignite the dish in a muffle furnace at 550°C for 1 hour. After ignition, allow the
vessel to partially cool in air and transfer to desiccator, cool and weigh.

F) Calculations:

Calculate the fixed residue and volatile residue as follows (total filterable or non-filterable):

Volatile residue, mg/L = (A-B) x 1000 / V

Fixed residue, mg/L = (B-C) x 1000 / V

Where,
A = mass in mg of residue and dish/filter before ignition
B = mass in mg of residue and dish/filter after ignition,
C = mass in mg of dish/filter, and
V = volume in ml of the sample.

H) Conclusion:
 Total Fixed Residue: The dish with residue after completion of test for total residue is
heated in a muffle furnace at 550°C for 1 hour. Total fixed and volatile residue are calculated
from loss in mass, on ignition.

 Filterable Fixed Residue: The dish with residue after completion of test for filterable
residue is heated in a muffle furnace at 550°C for 1 hour. Filterable fixed and volatile residue
are calculated from loss of mass, on ignition.

 Non-filterable Fixed Residue: The filter with residue after completion of test for non-
filterable residue is heated in a muffle furnace at 550°C for 1 hour. Non-filterable fixed and
volatile residue is calculated from loss in mass after ignition.

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