ENVIRONMENTAL ENGINEERING

ADVANCE SURVEYING LAB MANUAL

S.no LIST OF EXPERIMENT

1 To Study the various standards for water.
2 To Study of sampling for water.
3 To determine the turbidity of the given sample
4 To determine the coagulant dose required to treat the given turbid water sample.
5 To determine the conc. Of chloride in a given water sample
6 Determination of temporary, permanent and total hardness of water by complex
metric titration method.
7 Determination of residual chlorine by “ Chloroscope”
8 Determination of Alkalinity in a water samples
9 Determination of Acidity in a water Samples
10 Determination of Dissolved oxygen (DO) in the water sample

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.1
Aim:To Study the various standards for water.
Various standard of water are as follows:
1. Taste and Odour: -Taste and odour can originate from natural inorganic and
organic chemical contaminants and biological sources or processes (e.g. aquatic
microorganisms), from contamination by synthetic chemicals, from corrosion or as a
result of problems with water treatment (e.g. chlorination). Taste and odour may also
develop during storage and distribution as a result of microbial activity..

2. pH:- pH is an indicator of acidity or alkalinity. PH is a logarithmic scale and an

increase or decrease of one pH unit is a 10 fold change. Neutral water has a pH of 7,
acidic solutions have values between 0- 6 and alkaline solutions have values
between 8-14.

3. Temperature: It is a measure of the average energy (kinetic) of water molecules. It

is measured on a linear scale of degrees Celsius or degrees Fahrenheit. It is one of
the most important water quality parameters. Temperature affects water chemistry
and the functions of aquatic organisms. It influences the: 1) Amount of oxygen that
can be dissolved in water, 2) Rate of photosynthesis by algae and other aquatic
plants, 3) Metabolic rates of organisms, 4) Sensitivity of organisms to toxic wastes,
parasites and diseases, and timing of reproduction, migration, and aestivation of
aquatic organisms.

4. Turbidity is a measure of the cloudiness or haziness in water caused by suspended

solids (eg sediment, algae). Turbidity is expressed in Nephelometric Turbidity Units
(NTU) and is measured using a relationship of light reflected from a given sample.

5. Conductivity: This is a measure of the capability of a solution such as water in a

stream to pass an electric current. This is an indicator of the concentration of
dissolved electrolyte ions in the water. It doesn't identify the specific ions in the
water. However, significant increases in conductivity may be an indicator that
polluting discharges have entered the water.

6. Total Hardness: Hardness is predominantly caused by divalent cations such as

calcium, magnesium, alkaline earth metal such as iron, manganese, strontium, etc.
The total hardness is defined as the sum of calcium and magnesium concentrations,
both expressed as CaCO3 in mg/L. Carbonates and bicarbonates of calcium and
magnesium cause temporary hardness. Sulphates and chlorides cause permanent
hardness.

7. Dissolved Oxygen (DO): Dissolved oxygen is oxygen gas molecules (O2) present in
the water. Plants and animals cannot directly use the oxygen that is part of the water
molecule (H2O), instead depending on dissolved oxygen for respiration. Oxygen
enters streams from the surrounding air and as a product of photosynthesis from

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

aquatic plants. Consistently high levels of dissolved oxygen are best for a healthy
ecosystem. Levels of dissolved oxygen vary depending on factors including water
temperature, time of day, season, depth, altitude, and rate of flow. Water at higher
temperatures and altitudes will have less dissolved oxygen. Dissolved oxygen
reaches its peak during the day. At night, it decreases as photosynthesis has stopped
while oxygen consuming processes such as respiration, oxidation, and respiration
continue, until shortly before dawn. Human factors that affect dissolved oxygen in
streams include addition of oxygen consuming organic wastes such as sewage,
addition of nutrients, changing the flow of water, raising the water temperature, and
the addition of chemicals. Dissolved oxygen is measured in mg/L.
 0-2 mg/L: not enough oxygen to support life.
 2-4 mg/L: only a few fish and aquatic insects can survive.
 4-7 mg/L: good for many aquatic animals, low for cold water fish
 7-11 mg/L: very good for most stream fish.
8. Phosphates: Occur in natural or wastewaters as orthophosphates, condensed
phosphates and naturally found phosphates. Their presence in water is due to
detergents, used boiler waters, fertilizers and biological processes. They occur in
solution in particles or as detritus. They are essential for the growth of organisms
and a nutrient that limits the primary productivity of the water body. Inorganic
phosphorus plays a dynamic role in aquatic ecosystems; when present in low
concentration is one of the most important nutrients, but in excess along with nitrates
and potassium, causes algal blooms. It is calculated by the stannous chloride
method. In acidic conditions orthophosphate reacts with ammonium molybdate
forming Molybdophosphoric acid, reduced further to molybdenum blue by stannous
chloride. The intensity of the blue colour is directly proportional to the concentration
of phosphate. The absorbance is noted at 690nm using spectrophotometer.

9. Chlorides: The presence of chlorides in natural waters can mainly be attributed to

dissolution of salt deposits in the form of ions (Cl- ). Otherwise, high concentrations
may indicate pollution by sewage, industrial wastes, intrusion of seawater or other
saline water. It is the major form of inorganic anions in water for aquatic life. High
chloride content has a deleterious effect on metallic pipes and structures, as well as
agricultural plants.

10. Biological Oxygen Demand (BOD): Biological Oxygen Demand (BOD) is the
amount of oxygen required by microorganisms for stabilizing biologically
decomposable organic matter (carbonaceous) in water under aerobic conditions. The
test is used to determine the pollution load of wastewater, the degree of pollution
and the efficiency of wastewater treatment methods. 5-Day BOD test being a
bioassay procedure (involving measurement of oxygen consumed by bacteria for
degrading the organic matter under aerobic conditions) requires the addition of
nutrients and maintaining the standard conditions of pH and temperature and
absence of microbial growth inhibiting substance.

11. Chemical Oxygen Demand (COD): Chemical oxygen demand (COD) is the
measure of oxygen equivalent to the organic content of the sample that is susceptible
to oxidation by a strong chemical oxidant. The intrinsic limitation of the test lies in
its ability to differentiate between the biologically oxidisable and inert material. It is
measured by the open reflux method.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

12. Sludge Volume Index (SVI): SVI is used to describe the settling characteristics of
sludge in the aeration tank in Activated Sludge Process. It is a process
controlparameter to determine the recycle rate of sludge. It is defined as 'the volume
(in ml) occupied by 1 gram of activated sludge after settling the aerated liquid for 30
minutes.

Following table indicates the various desirable limits of various standard of water
parameter.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.2
Aim:To Study of sampling for water.
Sampling Programme and Procedures
The collection of a representative sample is the most important function of an
environmentalist. The interpretation of results and recommendation for prevention
and corrective treatment are all based on the analysis report. Scrupulous care in the
collection of samples is therefore necessary to ensure that the sample is
representative of the body of water under examination and to avoid spoilage and
accidental contamination of the sample during collection and transport.
Methods of sampling
Three types of samples are often collected depending on situations
a) Grab Samples
Grab samples are samples collected at a designated place at a particular time. They
represent the composition at the time and space. When a source is known to vary in
time, as in the case of waste effluents, grab samples collected at various time
intervals and analysed separately can be of greater value.

b) Composite samples
Composite samples are a mixture of grab samples collected at one sampling point at
different times. Individual samples are collected in wide mouth bottles every hour
and mixed in volume proportional to the flow. The composite values are useful for
observing average values.

c) Integrated samples
Integrated samples are a mixture of grab samples collected from different points
simultaneously and mixed in equal volumes. Individual samples are collected from
both banks of a river and at varying depths to represent available situations.
Sampling and preservation Requirements:
1. Physical and Chemical Requirements:
For general physical and chenica1 examination, the sample should be collected in a
chemically clean bottle made of good quality glass fitted with a ground glass stopper
or a chemically inert polyethylene container. The volume of sample to be collected
would depend on the selection of tests; however, for general examination 3.0 litre
sample would be sufficient.

The following precautions must be taken while collecting the sample

i) The sampling location is representative of the water body

ii) The place is devoid of floating material
Where ever possible the sample should be collected 15cm, below the surface or as
the situation warrants.
No physical activity is permitted upstream of sampling point Shorter the time
between collection and examination, the reliable will be the analytical results. For
certain constituents and physical values, immediate analysis in the field is required,
because, the composition of water may change before it arrives at the laboratory.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

The maximum limits of storage are:

Unpolluted water: 72 hours
Slightly polluted. : 48 hours
Grossly polluted: 12hours
Some determinations are more likely to be affected by storage than others.
Temperature may change, pH may change significantly, and dissolved gases may be
evolved and lost (O2, CO2. and H2S)
Frequency of sampling:
Frequency depends on objectives. Yet, collection of samples of both raw and treated
waters should be carried out as frequently as possible and at least once in every three
months. Some waters undergo more pronounced seasonal variation and therefore
require more frequent testing. Samples from treatment units should be collected and
analyses frequently, at least one from each unit daily.
2. Bacteriological requirements:
The samples for bacteriological examination are collected in sterilized. neutral glass,
glass-stopper 80z, and 300 ml bottles. The stopper and the neck should be protected
by paper or parchment cover. If the sample is likely to contain traces of residual
chlorine, an amount equal to 3.0 mg of sodium thiosul1ite (Na2s203, 51120) to
neutralize chlorine is added to the bottle before sterilization. The sterilization is done
at 15 psi (121°C) for 20-30 minutes in an autoclave.
The sterilized sample bottle should be kept unopened until the time of collection.
The stopper should be removed with care to eliminate chances of spoiling and
contamination and should never the rinsed. After filling, the stopper should be
replaced immediately. The place of collection should be predetermined and
procedure of collection conditioned depending on the source.
The standard procedure in sampling from a water faucet or tap is as follows:
a) Flame the tap briefly to kill clinging bacteria. This can be done with a piece of
burning paper.
b) Turn on the water and allow it to run for 1 mm.
c) Remove the stopper from the bottle, being careful not to touch the inner portions
of the stopper or bottle neck.
d) Fill bottle carefully, allowing no water to enter that has come in contact with
hands. It is sometimes necessary to collect a sample from a reservoir or basin. If the
water can be reached, remove the stopper, plunge the bottle below the surface and
move the bottle while it is filling, so that no water will enter that has been in contact
with hand. If the water is out of reach, as in a dug well, the bottle can be lowered
with a cord.
The sample after collection should be examined immediately, preferably within one
hour. If the conditions do not permit immediate examination, the sample should be
stored at low temperatures. This period should in case be more than 24 hours. If
storage or transportation is necessary, they should be got at a temperature between
0°C and 10°C
Frequency of sampling:

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

The frequency of sampling should be fixed depending on the magnitude of the

problem involved. The number of samples to be examined from drinking water
supply distribution system is normally decided on the basis of population served as
given in the tabulation:
Population Treated / untreated water entering
distribution system
Max.interval Max.no.of
between samples to be
successive examined.
sampling
Upto 1 month One sample
20,000 for every 5000
population
20,001 – 15 days
50000
50,001 – 4 days
1,00,000
More than 1 day One sample for
100,000 every 10,000
population

The raw water should be examined as frequently as the situation demands. The
frequency is also determined based on objectives of study.
3. Biological Requirements: In general the samples for biological examination are
collected in wide mouth, clean glass bottles of 2.0 litre capacity. They are never
filled completely. This method is employed when total microscopic count is the aim.
In some specific cases the concentrate of a sample may be collected through
plankton nets made of bolting silk cloth, or the. Sample filtered through Sedge wick
Rafter funnels.

In general the sample must be examined microscopically within one hour of

collections. If the facilities do not permit an immediate examination, it should be
preserved after collection by addition of 2 ml neutralized (pH 7.0) formaline to each
100 ml of the sample.

There is no practice about the frequency of sampling but the examination should be
made regularly, or else as the situation demands. Benthos study is complex,
Collection through cages placed at proper preselected sites for a defined period of
time is recommended.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.3
AIM: To determine the turbidity of the given sample.

APPARATUS:Nephelo – Turbidity meter with sample cell

Reagents for calibration of the instrument:

Solution 1: Dissolve 1 gm Hydrazine Sulphate (NH2)2H2So4 (carcinogen) in

distilled water and dilute to 100 ml in a volumetric flask

Solution 2: Dissolve 10 gms Hexamine LR grade (CH2)2N4 in distilled water and

dilute to 100 ml in a volumetric flask.

Take 12.5 ml of solution 1 and 12.5 ml of solution 2 in a 100 ml volumetric flask

and dilute to 100 ml, allow to stand for 24 hours at 250C. The turbidity of this
suspension is 1000 Nephelometric Turbidity Unit (NTU).

THEORY: Turbidity is an expression of optical property that uses light scattering

properties of suspension in the sample. Turbidity in water is caused by suspended
matter such as clay, silt, finely divided organic and inorganic matter soluble, colored
organic compounds, plankton and other microscopic organisms.

Turbidity is measured by shining light through a sample and measuring the degree of
scattering as measured by a light detector placed at right angles to the original light
path. Above measuring technique is known as Nephelometry.

Turbidity can also be measured by shining light through a sample and measuring the
degree of light penetration as measured by a light detector placed in line to the
original light path. This measuring technique is known as Turbidimetry.

PRINCIPLE
Nephelo-Turbidity meter operates on the principle that light passing through a
substance is scattered by matter suspended in the substance. In this instrument, a
strong light beam is passed upward through a tube containing the sample. As the
beam passes through the sample, the light is scattered in proportion to suspended
particles. At 900 to the light path, this scattered light is sensed by the phototube to
give the turbidity reading. The unit of measurement is NTU.

CALIBRATION OF THE INSRTRUMENT:

1. Switch on the instrument and keep it ON for some time

2. Select appropriate range depending upon the expected turbidity of the sample.

3. Set zero of the instrument with turbidity free water using blank solution and
adjust 000 with the ‘set zero’ knob. The CAL control should be moved by 5 turns
clockwise from 0 position.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

4. Now in another test tube, take standard suspension that already prepared. For
0-200 NTU range use 100 NTU solution and for higher range use 400 NTU solution
as standard.

PROCEDURE
1. Take the test tube containing distilled water in the test tube holder and close
the test tube holder lid.
2. Select the required range for measurement.
3. Adjust the display to 000 by adjusting ‘set zero’ knob.
4. Remove the test tube containing distilled water & insert another test tube
containing standard solution (say 400 NTU). Place it in the test tube holder.
5. Take the measurement of the solution suspension& adjust the ‘calibrate’ knob
so that the display reads the selected standard solution value.
6. Again check the display zero with the test tube containing distilled water.
7. Now the instrument is ready to take measurement of any unknown suspension.

RESULTS

Turbidity of the given sample of water = NTU

INTERFERENCE

1. Turbidity can be determined for any water sample that is free of debris and
rapidly settling coarse sediments.
2. Dirty glass ware or the presence of air bubbles disturb the surface visibility of
the sample & will give false results.
3. Water colour due to dissolved substances that absorb light causes measured
turbidity to be lowest.

PRECAUTIONS

1. Sample test tube must be thoroughlycleaned both inside and outside. In case
the test tube gets scratched, discard it.
2. Do not touch the test tube where the light strikes i.e.at the sides of the test
tube. So hold the test tube only at the top end.
3. Fill the test tube with samples or standards which have been thoroughly
agitated. Allow sufficient time for the air bubbles to escape otherwise the reading
will slowly come down. When the readings are taken in the agitated state with air
bubbles, the readings will be higher.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.4
Aim: To determine the coagulant dose required to treat the given turbid water
sample.
Principle:
Coagulants are used in water treatment plants
(i) To remove natural suspended and colloidal matter,
(ii) To remove material which do not settle in plain sedimentation, and
(iii) To assist in filtration
Alum [Al2(SO4)3. 18H2O] is the most widely used coagulant. When alum solution is
added to water, the molecules dissociate to yield SO2–4and Al3+. The +ve species
combine with negatively charged colloidal to neutralize part of the charge on the
colloidal particle. Thus, agglomeration takes place. Coagulation is a quite complex
phenomenon and the coagulant should be distributed uniformly throughout the
solution.
Apparatus:
1. Jar Test Apparatus
2. Glass Beakers
3. Pipette
4. Nephelometer
5. pH meter
Reagents
1. Alum solution (1mL containing 10 mg of alum)
2. Lime
3. Acid/alkali
Procedure
1. Take 1-litre beakers and fill them with sample up to the mark.
2. Keep each beaker below each paddle and lower the paddles, such that each one is
about 1cm above the bottom.
3. Find the pH of the sample and adjust it to 6 to 8.5.
4. Pipette 1, 2, 3, 4, 5, 6 mL of the alum solution into the test samples.
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 30 minutes.
7. Stop the machine, lift out the paddles and allow to settle for 30 minutes.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

8. Find the residual turbidity of the supernatant using nephelometer.

9. Plot a graph with alum dosage along x-axis and turbidity along y-axis.
10. The dosage of alum, which represents least turbidity, gives Optimum Coagulant
Dosage (O.C.D.).
11. Repeat steps 1–10 with higher dose of alum, if necessary.
Observation
Trial No. Alum Dosage in Turbidity in
mg/L NTU

Results:
Optimum coagulant dosage =

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.5
Aim: To determine the conc. Of chloride in a given water sample
Principle: If water containing chlorides is titrated with silver nitrate solution,
chlorides are precipitated as white silver chloride. Potassium chromate is used as
indicator, which supplies chromate ions. As the concentration of chloride ions
approaches extinction, silver ion concentration increases to a level at which reddish
brown precipitate of silver chromate is formed indicating the end point.
Apparatus:
1. Burette
2. Pipettes
3. Erlenmeyer flasks
4. Measuring cylinder
Reagents:
1. Chloride free distilled water.
2. Standard silver nitrate solution (0.0141N)
3. Potassium chromate indicator.
4. Acid or alkali for adjusting pH.
5. Potassium chromate indicator: Dissolve 50 g potassium chromate (K2Cr2O4) in a
little distilled water. Add silver nitrate solution until a definite red precipitate is
formed. Let stand for 12 hours, filter and dilute the filtrate to 1 litre with distilled
water.
6. Standard silver nitrate solution 0.0141 N: Dissolve 2.395 g AgNO3 in distilled
water and dilute to 1 litre. Standardise against 0.0141 N NaCl. Store in a brown
bottle; 1 mL = 500 µg Cl2.
7. Standard sodium chloride 0.0141N: Dissolve 824.1 mg NaCl (dried at 140°C) in
chloride free water and dilute to 1 litre. 1mL = 500 µg Cl2
8. Aluminium hydroxide suspension: Dissolve 125 g aluminium potassium sulphate
in 1 litre water. Warm to 60°C and add 55 mL concentrated NH4OH slowly with
stirring. Let stand for 1 hour, transfer the mixture to a large bottle. When freshly
prepared the suspension occupies a volume of approximately 1 litre.
Procedure
1. Take 50mL of sample (V) and dilute to 100mL.
2. If the sample is coloured add 3mL of aluminium hydroxide, shake well; allow to
settle, filter, wash and collect filtrate.
3. Sample is brought to pH 7-8 by adding acid or alkali as required.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

4. Add 1mL of indicator (Potassium chromate).

5. Titrate the solution against standard silver nitrate solution until a reddish brown
precipitate is obtained. Note down the volume (V1).
6. Repeat the procedure for blank and note down the volume (V2).
Observation:
Water sample vs silver Nitrate (0.0141 N)
(Potassium Chromate Indicator )

Sample No. Trail no. Volume of Burette Volume of Chloride

sample reading silver Nitrate mg/L

1
1 2
3
1
2 2
3
1
3 2
3

V=
V1 =
V2 =
N=
Chloride in mg/L = (V1-V2) x N x 35.46 x 1000
V
= (V1-V2) x 500 =………mg/L
V
Result:
Description of sample Chloride concentration in
mg/L

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.6

Aim
Determination of temporary, permanent and total hardness of water by complex
metric titration method.

Reagents/Chemicals
Standard EDTA solution............, water sample, standard hard water, buffer solution,
Eriochrome black-T as an internal indicator

Apparatus
Burette, pipette, measuring flask, conical flask.

Theory
The hardness of water can be determined by complexometric titration. EDTA is used
as complexing reagent. The Ca++ and Mg++ present in water are titrated with EDTA
using Eriochrome black-T as an indicator.
When Eriochrome black –T indicator is added to hard water solution at pH 9 to 10, it
gives wine red coloured unstable complex with Ca++ and Mg++ ions of the water
sample. As this solution (wine red colour complex) is titrated against EDTA the free
Ca++ and Mg++ ions in water form stable metal ion EDTA complex with the result ,
the indicator is set free, which gives blue colour to the solution.

Structure of Eriochrome black-T

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Observations
Reading with standard hard water

S. Volume Burette Reading (ml) Volume

No of of
water EDTA
sample used
V (ml) (ml)
(V1)

Initial Final

1.

2.

3.

Reading with hard water sample

S. Volume Burette Reading (ml) Volume

No of of
R
water EDTA
e
sample used
a
V (ml) (ml)
d
i (V2)
n
g Initial Final

w 1.
i
2.
t
h 3.

boiled Water

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

S. Volume Burette Reading (ml) Volume

No of water of
sample EDTA
V (ml) used
(ml)
(V3)

Initial Final

1.

2.

3.

Result : The temporary hardness of the given water sample is

_________ ppm
: The permanent hardness of the given water sample is
__________ ppm
: The total hardness of the given water sample is
__________ ppm

Precautions

1 The amount of indicator was same in all the titrations.

.

2 The pH of the solution was maintained carefully to precipitate the complex.

.

3 The apparatus was rinsed with distilled water.

.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.7
Aim: Determination of residual chlorine by “ Chloroscope”
Apparatus Required:Comparator box or chloroscope
Chemicals Required: Orthotolidine Solution
Theory:The prime purpose of disinfecting public water supplies and waste effluents
is to prevent the spread of waterborne diseases. The applications of chlorine for
disinfection of drinking water go far back as the nineteenth century. Chlorine is used
in the form of free chlorine or hypochlorite .In either form, it acts as a protein
oxidizing agent and often dissipates itself in side reactions so rapidly that little
disinfection is accomplished until amounts in excess of the chlorine demand have
been added.
Residual chlorine is the chlorine left in the water after the required contact period.
Residual chlorine ensures complete killing of bacteria and oxidation organic matters.
When filtered water is chlorinated, it is consumed initially for killing
microorganisms and then for oxidizing organic matter. When oxidation is complete
and break point is reached, whatever chlorine is added appears as residual chlorine
.For satisfactory care of future contamination of water usually free chlorine residual
of 0.2 to 0.3mg/L is sufficient for a contact period of 10- 20 minutes.
Procedure:
Residual chlorine can be tested by three methods:
1. Orthotolidene Test
2. Starch iodide Test
3. DPD Test
Orthotolidine test:-
 First take 10 ml of water sample in a test tube.
 Then 0.01 gm of bleaching powder is added to the sample.
 Kept the mixture for 15 min without any disturbing.
 After that to this chlorinated water we have to add 2-3 drops of orthotolidine
solution.
 The yellow colour indicates that the residual chlorine is present in the sample.
 Then note down the residual chlorine present in diff. types of samples.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Observation:-
Sl.n Name Sourc Residu Remar
o. of the e of al k
Sampl the chlorin
e Sampl e
e

Result:
From the above experiment we have calculate the residual chlorine of the diff
samples like__________ and the value is______.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.8
Aim: - Determination of Alkalinity in a water samples.
Apparatus Required:
1. Burette
2. Pipette
3. Beaker(100ml)
Chemicals Required:
1. Sulphuric Acid, H2SO4 (0.02N)
2. Phenolphthalein indicator
3. Methyl Orange indicator
Theory:Alkalinity is defined as the quantity of ions in water that will react to
neutralize hydrogen ions. Alkalinity is thus a measure of the ability of water to
neutralize acids. Constituents of alkalinity in natural water systems include
carbonate, bicarbonate, hydroxide, hyposilicate, hypoborate, hypophosphate,
hydrogen sulphide. These compounds result from the dissolution of mineral
substances in the soil and atmosphere. Phosphates may also originate from
detergents in wastewater discharges and from fertilizers and insecticides from
agricultural land. Hydrogen Sulphide may be products of microbial decomposition
of organic material. By far the most common constituents of alkalinity are
bicarbonates, carbonates, and hydroxide. In addition to their mineral origin, these
substances can originate from CO2, a constituent of the atmosphere and a product of
microbial decomposition of organic material.

Significance:
1. The alkalinity of water has little public health significance. Highly alkaline
waters are usually unpalatable and consumers tend to seek other supplies.
2. Chemicals used for coagulation of water and wastewater react with water to
form hydroxide precipitates. The hydrogen ions released react with the alkalinity of
the water. Thus, the alkalinity acts to buffer the water in pH range where the
coagulant can be effective. Alkalinity must be present in excess of that destroyed by
the acid released by the coagulant for effective and complete coagulation to occur.
3. Alkalinity is a major item that must be considered in calculating the lime and
soda ash requirements in softening of water by precipitation methods.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

4. Alkalinity is an important parameter involved in corrosion control.

5. Alkalinity measurements are made as a means of evaluating the buffering
capacity of waste water and sludge. They can also be used to access the ability of
natural water to resist the effects of acid rain.
6. Municipal authorities prohibit the discharge sewers. Alkalinity is an important
factor in determining the amenability of waters to biological treatment.

Procedure:
1. 20ml of sample was pipetted into a 100 ml beaker and 2 to 3 drops of
phenolphthalein indicator is added to it.
2. The sample was titrated with standard sulphuric acid till the pink colour
observed by phenolphthalein indicator just disappears.
3. The volume (A) of standard H2SO4 acid solution used was recorded and used
to determine the phenolphthalein alkalinity has been determined.
4. 2 to 3 drops of mixed indicator were added to the solution in which the
phenolphthalein alkalinity has been determined.
5. The titration was carried out with standard H2S04 to light pink colour. The
volume (B) of acid used for this is recorded.
Observation:-
Sl.n Name Sourc Alkalinit Remar
o of the e of y of the k
sampl the sample
e sampl
e

Calculation:
Phenolphthalein alkalinity = (A×N×5000)/V as mg/L of CaCO 3.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Total alkalinity = (A+B) N×5000/V as mg/L of CaCO3.

Where,
A = ml of standard H2SO4 acid used to titrate upto phenolphthalein end point.
B = ml of standard H2SO4 acid used to titrate upto mixed indicator end point.
N = normality of acid used.
V = Volume in ml of water sample taken for the test. Given,
N = 0.02N (normality of H2SO4)
V = 20ml of the given water sample
A and B were noted from the observation table.
Result:
The alkalinity of the given water samples were found to be ________ mg/L of
CaCO3.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.9
Aim: Determination of Acidity in a water Samples.
Apparatus Required:
1. Burette
2. Pipette
3. Beaker (100 ml)
𝐂𝐡𝐞𝐦𝐢𝐜𝐚𝐥𝐬𝐫𝐞𝐪𝐮𝐢𝐫𝐞𝐝:
1. Sodium hydroxide solution, NaOH (0.02N)
2. Methyl orange indicator
3. phenolphthalein indicator
𝐓𝐡𝐞𝐨𝐫𝐲:
Acidity of water is its quantitative capacity to react with a strong base to a designatedpH. It
may be defined as the equivalent concentration of hydrogen ion inmg/L. Acidity of neutral
water is caused by carbon dioxide or by strong mineral acids, the former being the effective
agent in water having pH value greater than 4 and the latter the effective agent in water with
pH value less than 4. Natural water and most industrial wastewater that have a pH value
below4, contain mineral or methyl orange acidity. Mineral acid are essentially neutralised by
the time the pH has been raised to about3.7. Results are reported in terms of methyl orange
acidity expressed asCaCO3. Since CaCO3 has an equivalent weight of 50,N/50 or 0.02N
NaOH is used as the titrating agent so that 1mL is equivalent to 1mg of acidity. Titration of
a sample to phenolphthalein end point of pH 8.3 measures both mineral acidity plus acidity
due to weak acids. This total acidity is also termed as phenolphthalein acidity.

𝐒𝐢𝐠𝐧𝐢𝐟𝐢𝐜𝐚𝐧𝐜𝐞:
1. Acidic waters are of concern because of their corrosive characteristics and the
expense involved in removing or controlling the corrosion-producing substance. The
corrosive factor in most waters is carbon dioxide, but in many industrial
wastewaters, it is mineral acidity.
2. In the development of new public water supplies, the carbon dioxide acidity is
an important factor that must be considered in the treatment method and the facilities
needed.
3. Many underground supplies require overcoming corrosive characteristics
resulting from carbon dioxide. The amount present in an important factor in
determining whether removal by aeration or simple neutralization with lime or
sodium hydroxide will be chosen as treatment method.

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

4. The quantities of chemicals, size of chemical feeders, storage space and cost
of treatment are determined from the laboratory data base on acidity.
5. When biological processes of treatment are used, the pH must be maintained
in between 6 to 8.5. This criterion often requires adjustments of pH to favourable levels
and calculation of the amount of chemical needed is based upon acidity values in most
cases.
Procedure:
1. 20ml of sample is pipette into a 100ml beaker and 2 to 3 drops of methyl
orange indicator is added to it.
2. The sample is titrated with standard sodium hydroxide solution till the colour
changes to faint orange.
3. The volume (A) of standard sodium hydroxide solution used is recorded and
used to determine the methyl orange acidity.
4. 2 to3 drops of phenolphthalein indicator are added to the solution in which the
methyl orange acidity as been determined.
5. The titration is carried out with standard sodium hydroxide solution to the
appearance of faint pink colour. The volume of (B) of sodium hydroxide used for
this is recorded.
Observation:-
Sl.n Name Sourc Acidit Remar
o of the e of y k
sampl the
e sampl
e

Calculation:
For calculation of acidity of given sample
Acidity of indicator

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Methyl orange (indicator acidity) = {(a x n x 50000) ÷v} mg/l of caco 3

Total acidity = {(a+b) x n x 50000}/v mg/l of caco 3

Where
A -ml of standard NaOH solution used to titrate methyl orange end point
B-ml of standard NaOH solution used to titrate upto phenolphthalein end point
N-normality of sodium hydroxide used
V=volume in ml of sample taken for test

Result
Therefore the acidity of the given sample is found to be _________

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Experiment No.10
Aim: Determination of Dissolved oxygen (DO) in the water sample.
Apparatus: Burette, conical flask, pipette, measuring cylinder .
Reagents:
1. Manganese sulfate solution: Dissolve 480 g MnSO4.4H2O, 400 g
MnSO4.2H2O or 364 g MnSO4.H2O in distilled water, filter, and dilute to 1L. The
MnSO4 solution should not give a color with starch when added to an acidified
potassium iodide (KI) solution.
2. Alkali-iodide-azide reagent
3. Sulfuric acid: One mL is equivalent to ~ 3mL alkali-iodide-azide reagent.
4. Starch solution: Dissolve 2 g laboratory-grade soluble starch and 0.2 g
salicyclic acid as preservative in 100 mL hot distilled water.
5. Standard sodium thiosulfate titrant: Dissolve 6.205 g Na2S2O3 .5H2O in
distiller water and add 1.5 mL 6N NaOH or 0.4 g solid NaOH and dilute to 1000 ml.
Standardize with biiodate solution.
6. Standard potassium bi-iodate solution (0.0021M): Dissolve 812.4 mg KH(IO3)
in distilled water and dilute to 1000 mL.
7. Standardization: Dissolve e ~ 2 g KI, free from iodate in an Erlenmeyer flask
with 100 to 150 mL distilled water; add 1 mL 6N H2SO4 or a few drops of conc.
H2SO4 and 20.00 mL standard biiodate solution. Dilute to 200 mL and titrate
liberated iodine with thiosulfate titrant, adding starch toward end of titration, when a
pale straw color is reached. When the solution is of equal, 20.00 mL 0.025M
Na2S2O3 should be required. If not, adjust the Na2S2O3 solution to 0.025M.

Theory:-

Dissolved oxygen (DO) levels in environmental water depend on the physiochemical

and biochemical activities in water body and it is an important useful in pollution
and waste treatment process control. Two methods are commonly used to determine
DO concentration: (1) The iodometric method which is a titration-based method and
depends on oxidizing property of DO and (2) The membrane electrode procedure,
which works based on the rate of diffusion of molecular oxygen across a membrane.

In the Iodometric method, divalent manganese solution is added to the solution,

followed by addition of strong alkali in a glass-stopper bottle. DO rapidly oxidize an

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

equivalent amount of the dispersed divalent manganese hydroxide precipitates to

hydroxides of higher valence states. In the presence of iodide ions in an acidic
solution, the oxidized manganese reverts to the divalent state, with the liberation of
iodine equivalent of the original DO content. The iodine is then titrated with a
stranded solution of thiosulfate.

The titration end point can be detected visually with a starch indicator.

MnSO4 + 2KOH Mn (OH)2 + K2SO4

Mn(OH)2 + O MnO(OH)2

MnO(OH)2 + 2H2SO4 + 2KI MnSO4 + K2SO4 + 3H2O + I2

Procedure:
1. Collect the water sample without bubbling in 200ml glass bottle.
2. Add 2 ml of manganoussulfate (MnSO4.H2O) solution inserting the tip of
pipette tip into the sample because the drops of solution can allow inserting the
oxygen into the solution.
3. Add 2 ml of the alkali-iodide-azide reagent by above method.
4. Allow reacting the solutions with the oxygen present in the sample.
5. When precipitates are settled down at the bottom add 2 ml of concentrated
sulfuric acid by placing the pipette tip very near to sample surface.
6. Mix well to dissolve the precipitates.
7. Take 50 ml of sample from in a flask.
8. Titrate immediately with sodium thiosulfate solution using starch indicator
until blue color disappears and note down the burette reading.
9. Determine the burette reading for blank in the same manner.
Observation:
S.n Sampl Initial Final Volu
o e (ml) value value me of
(Buret (Buret Titran
te te t used
scale) scale) (ml)
1
2

IES COLLEGE BHOPAL

 ENVIRONMENTAL ENGINEERING

Calculations:
D.O. in mg/lit = 8*100*N/V * v
Where: V = Volume of sample taken (ml)
v = Volume of used titrant (ml)
N = Normality of titrant
8 is the constant since 1ml of 0.025N Sodium thiosulphate solution is equivalent to
0.2mg oxygen.

IES COLLEGE BHOPAL