GLOBAL ACADEMY OF TECHNOLOGYLab Manual, ISO 14001 Environmental Management, Regulatory Standards for Drinking Water and Sewage disposal. 2. Clair Sawyer and Perry McCarty and Gene

Department of Civil Engineering – 15CVL76 i

GLOBAL ACADEMY OF TECHNOLOGY

FOREWORD

Global Academy of Technology strives to inculcate environmental consciousness among its

student community. This course- Environmental Engineering Laboratory (15CVL76) as prescribed by

VTU, Belagavi will aid in its fulfilment.

Environmental Engineering involves planning, design, construction and operation of

equipment, systems, and structures for the protection and enhancement of the environment. Although

traditionally a significant part of the Environmental Engineering encompassed water and waste water

collection, treatment and disposal to ensure sanitary living conditions for the public, in recent times, its

scope has grown abundantly covering additionally aspects of air pollution control, waste water

treatment/water pollution control, hazardous waste management, and solid waste management.

Environmental site assessments for property and environmental impact assessments for projects

and activities also form a significant part of the job of environmental engineers. Another concern

regarding the environment is, soil and groundwater contamination, which is being addressed by

Environmental engineers. Today, environmental engineers work on all the above subjects with more

intensive land and resource usage, along with cleaning up past pollution, and integrating with multi-

disciplinary teams to develop alternate energy sources, and more.

The current manual is prepared to equip students with information required to conduct

experiments necessary to analyse the quality of water and wastewater along with basic principles of the

working of experiment. The environmental significance of each parameter is incorporated for better

understanding of students.

The regulatory standards for drinking water as per World Health Organisation (WHO) and

Bureau of Indian Standards(BIS) is incorporated in the manual to train student in understanding the

standard requirements by the authorities and check the water’s compatibility for consumption or other

usage by comparing it with the prescribed Central Pollution Control Board (CPCB), BIS and WHO

standards. With this, the student will be able to apply the gained knowledge for the design of water and

waste water treatment units considering environmental and public protection.

The manual was prepared considering the guidelines given by CPCB and APHA standards, thus

ensuring the quality of the information given herewith.

Ms. Khushbu.K.Birawat

Assistant Professor

Mrs. Vidyashree D

Assistant Professor

http://www.brighthub.com/environment/science-environmental/articles/66158.aspx

http://www.brighthub.com/environment/science-environmental/articles/66158.aspx

Department of Civil Engineering – 15CVL76 ii


VISION OF THE INSTITUTE

Become a premier institution imparting quality education in engineering and management to meet

the changing needs of society

MISSION OF THE INSTITUTE

M1. Create environment conducive for continuous learning through quality teaching and learning

processes supported by modern infrastructure

M2. Promote Research and Innovation through collaboration with industries

M3. Inculcate ethical values and environmental consciousness through holistic education programs

DEPARTMENT OF CIVIL ENGINEERING

VISION

To become a leading department oriented to serve the basic wants of human being related to food,

air, shelter and transportation, by providing quality education.

MISSION

M1. Create a favourable environment for learning, teaching & continuous improvement for

implementation of various civil engineering facilities.

M2. Promote professionalism, innovation and research through collaboration with industries to

realize cost & resource effective, stable, quality structures.

M3. Inculcate environmental consciousness and ethical values through interconnected training

programs to ensure sustainability and client satisfaction.

Department of Civil Engineering – 15CVL76 iii


PROGRAM EDUCATIONAL OBJECTIVES-PEO’s

The program educational objectives of Civil Engineering are to enable students in,

PEO-1: Developing careers in government and private civil engineering organizations and other

professionally related domains

PEO-2: Pursuing higher studies, and research to develop innovative solutions and technologies in

civil engineering and other multi disciplinary areas

PEO-3: Improving professional and personal traits aligned to professional ethics and environmental

compulsions

PEO-4: Professional leadership and Successful entrepreneurship

PROGRAM SPECIFIC OUTCOMES-PSO’s

PSO-1: Comprehend, analyze and design alternatives for execution of civil engineering facilities

PSO-2: Apply Standard Codes of Practices and schedule of rates for planning, design, quality

control, estimating & costing of civil engineering projects.

PSO-3: Evaluate the buildings for resource conservation.

PROGRAM OUTCOMES-PO’s

Engineering graduates will be able to:

1. Engineering knowledge: Apply the knowledge of mathematics, science, engineering fundamentals,

and an engineering specialization to the solution of complex engineering problems.

2. Problem analysis: Identify, formulate, review research literature, and analyze complex engineering

problems reaching substantiated conclusions using first principles of mathematics, natural sciences,

and engineering sciences.

3. Design/development of solutions: Design solutions for complex engineering problems and design

system components or processes that meet the specified needs with appropriate consideration for the

public health and safety, and the cultural, societal, and environmental considerations.

4. Conduct investigations of complex problems: Use research-based knowledge and research

methods including design of experiments, analysis and interpretation of data, and synthesis of the

information to provide valid conclusions.

Department of Civil Engineering – 15CVL76 iv


5. Modern tool usage: Create, select, and apply appropriate techniques, resources, and modern

engineering and IT tools including prediction and modelling to complex engineering activities with

an understanding of the limitations.

6. The engineer and society: Apply reasoning informed by the contextual knowledge to assess

societal, health, safety, legal and cultural issues and the consequent responsibilities relevant to the

professional engineering practice.

7. Environment and sustainability: Understand the impact of the professional engineering solutions

in societal and environmental contexts, and demonstrate the knowledge of, and need for sustainable

development.

8. Ethics: Apply ethical principles and commit to professional ethics and responsibilities and norms of

the engineering practice.

9. Individual and team work: Function effectively as an individual, and as a member or leader in

diverse teams, and in multidisciplinary settings.

10. Communication: Communicate effectively on complex engineering activities with the engineering

community and with society at large, such as, being able to comprehend and write effective reports

and design documentation, make effective presentations, and give and receive clear instructions.

11. Project management and finance: Demonstrate knowledge and understanding of the engineering

and management principles and apply these to one’s own work, as a member and leader in a team, to

manage projects and in multidisciplinary environments.

12. Life-long learning: Recognize the need for, and have the preparation and ability to engage in

independent and life-long learning in the broadest context of technological change.

Department of Civil Engineering – 15CVL76 v


CONTENTS

Contents

FOREWORD ................................................................................................................................................... i

VISION OF THE INSTITUTE .................................................................................................................... ii

MISSION OF THE INSTITUTE................................................................................................................. ii

DEPARTMENT OF CIVIL ENGINEERING ................................................................................................ ii

PROGRAM EDUCATIONAL OBJECTIVES-PEO’s ................................................................................. iii

PROGRAM SPECIFIC OUTCOMES-PSO’s .............................................................................................. iii

PROGRAM OUTCOMES-PO’s................................................................................................................... iii

GOVERNING REGULATIONS .................................................................................................................. vii

COURSE DETAILS ................................................................................................................................... viii

COURSE OUTCOMES .............................................................................................................................. viii

EVALUATION SCHEME (2015) .................................................................................................................. x

LABORATORY GUIDELINES.................................................................................................................... xi

EVALUATION SHEET ............................................................................................................................. xiii

IMPORTANCE OF ENVIRONMENTAL ENGINEERING LAB ............................................................. xiv

COLLECTION AND PRESERVATION OF SAMPLES ............................................................................ xv

GENERAL INFORMATION ...................................................................................................................... xix

QUALITY STANDARDS FOR MUNICIPAL OR DOMESTIC SUPPLIES ............................................. xx

WATER QUALITY CRITERIA AS PER CPCB NORMS ......................................................................... 24

WATER TREATMENT PLANT- FLOWCHART ...................................................................................... 25

WASTE WATER TREATMENT PLANT- FLOWCHART ....................................................................... 27

DETERMINATION OF pH OF WATER .................................................................................................... 30

DETERMINATION OF ACIDITY OF WATER ......................................................................................... 35

DETERMINATION OF ALKALINITY OF WATER ................................................................................. 40

DETERMINATION OF TEMPORARY HARDNESS, PERMANENT HARDNESS AND TOTAL

HARDNESS ................................................................................................................................................. 46

DETERMINATION OF DISSOLVED OXYGEN (DO) ............................................................................. 52

DETERMINATION OF BIOCHEMICAL OXYGEN DEMAND (BOD) .................................................. 56

DETERMINATION OF CHLORIDE CONTENT IN THE GIVEN SAMPLE ........................................... 60

DETERMINATION OF PERCENTAGE OF AVAILABLE CHLORINE IN BLEACHING POWDER .. 63

TO DETERMINE THE RESIDUAL CHLORINE....................................................................................... 67

DETERMINATION OF SOLIDS ................................................................................................................ 71

DETERMINATION OF TURBIDITY OF A GIVEN SAMPLE ................................................................. 78

Department of Civil Engineering – 15CVL76 vi


DETERMINATION OF OPTIMUM DOSAGE OF COAGULANT .......................................................... 81

DETERMINATION OF SODIUM CONTENT ........................................................................................... 85

DETERMINATION OF POTASSIUM CONTENT .................................................................................... 88

DETERMINATION OF NITRATES ........................................................................................................... 90

DETERMINATION OF IRON ..................................................................................................................... 92

DETERMINATION OF MANGANESE ..................................................................................................... 94

DETERMINATION CHEMICAL OXYGEN DEMAND (COD) ............................................................... 96

AIR QUALITY MONITORING .................................................................................................................. 99

DETERMINATION OF SOUND LEVEL ................................................................................................. 102

Department of Civil Engineering – 15CVL76 vii


GOVERNING REGULATIONS

ATTENDANCE REQUIREMENT

Each semester is considered as a unit and the candidate has to put in a minimum attendance

of 85% in each subject with a provision of condonation of 10% of the attendance by the

Vice-Chancellor on the specific recommendation of the Principal of the college where the

candidate is studying, showing some reasonable cause such as medical grounds, participation

in University level sports, cultural activities, seminars, workshops and paper presentation,

etc.

The basis for the calculation of the attendance shall be the period prescribed by the

University by its calendar of events.

The students shall be informed about their attendance position periodically by the colleges so

that the students shall be cautioned to make up the shortage.

A candidate having shortage of attendance in one or more subjects shall have to repeat the

whole semester and such candidates shall not be permitted to take admission to next higher

semester. Such students shall take readmission to the same semester in the subsequent

academic year.

INTERNAL ASSESSMENT MARKS

There shall be a maximum of 20 Internal Assessment Marks in each practical papers, the IA

marks shall be based on the laboratory journals/reports and one practical test.

A candidate failing to secure a minimum of 50% of the IA marks (10/20) in Practical, 50%

of marks in project work, shall not be eligible for the practical / project in the University

examination. For a pass in a Practical/Project/Viva-voce examination, a candidate shall

secure a minimum of 40% of the maximum marks prescribed for the University Examination

in the relevant Practical/ Project/ Viva-voce.

Department of Civil Engineering – 15CVL76 viii


COURSE DETAILS

Course Name : ENVIRONMENTAL ENGINEERING LABORATORY

Course Code : 15CVL76

Course Pre-requisite : Water supply and Treatment Engineering

COURSE OUTCOMES

Upon successful completion of this course, students will be able to

Subject code: 15CVL76 Subject: ENVIRONMENTAL ENGINEERING LABORATORY

COs COURSE OUTCOMES COGNITIVE

LEVEL

NO. OF

SESSIONS

MAPPED

POs

CO1

Conduct experiments and determine the

physical, chemical and biological characteristics

of water and wastewater.

Apply (L3) 12 PO1, PO4,

PSO1,PSO2

CO2 Compare the experimental results with standards

and deliberate based on the purpose of analysis. Apply (L3) 12

PO1, PO4,

PSO2

CO3 Determine type & degree of treatment, for water

and wastewater. Apply (L3) 08

PO4, PO6,

PO7, PSO1,

PSO2

CO4 Relate the significance of experimental results in

environmental engineering practices. Apply (L3) 08

PO4, PO6,

PO7, PO12,

PSO1

Department of Civil Engineering – 15CVL76 ix


Course Title: Environmental Engineering Laboratory

As per Choice Based Credit System (CBCS) scheme

SEMESTER:VII

Subject code 15CVL76 IA Marks 20

Number of lecture hours/week 1I+2P Exam Marks 80

Total Number of Lecture Hours 40 Exam Hours 03

Credits -02 Total Marks-100

SN Experiment

1 Determination of pH, Acidity and Alkalinity

2 Determination of Calcium, Magnesium and Total Hardness

3 Determination of Dissolved Oxygen

4 Determination of BOD

5 Determination of Chlorides

6 Determination of percentage of available chlorine in bleaching powder, Determination of

Residual Chlorine

7

Determination of Solids in Sewage

1. Total Solids,

2. Suspended Solids,

3. Dissolved Solids,

4. Volatile solids, fixed solids

5. Settleable solids

8 Determination of Turbidity by Nephelometer

9 Determination of Optimum Dosage of Alum using Jar test apparatus.

10 Determination of sodium and potassium using flame photometer

11 Determination Nitrates by spectrophotometer.

12 Determination of Iron & Manganese.

13 Determination of COD.

14 Air Quality Monitoring ( Ambient, stack, Indoor Air pollution)

15 Determination of Sound by Sound level meter at different location

Question Paper Pattern:

1. Two experiments shall be asked from the above set

2. One experiment to be conducted and for the other student should write detailed procedure.

Reference Material:

1. Lab Manual, ISO 14001 Environmental Management, Regulatory Standards for Drinking Water and Sewage disposal.

2. Clair Sawyer and Perry McCarty and Gene Parkin, “Chemistry for Environmental

Engineering and Science”, McGraw-Hill Series in Civil and Environmental Engineering.

3. Guide manual: Water & wastewater analysis, Central Pollution Control Board, Govt. of

India.

4. APHA standard methods for the examination of water and wastewater – 20th

edition.

5. Water supply engineering, S.K. Garg- 30th

Edition.

Department of Civil Engineering – 15CVL76 x


EVALUATION SCHEME (2015)

VTU LAB EVALUATION PROCESS

WEEK WISE VALUATION OF EACH EXPERIMENT

SL.NO ACTIVITY MARKS

1 Viva-Voce 4

2 Record / Manual 8

TOTAL 12

INTERNAL ASSESSMENT CALCULATION


1 Average of Weekly Entries 12

2 Internal Assessment Reduced To 8

TOTAL 20

EXTERNAL ASSESSMENT (End of Semester)


1 Write-Up 12

2 Conduction 56

3 Viva Voce 12

TOTAL 80

Department of Civil Engineering – 15CVL76 xi


LABORATORY GUIDELINES

1. Always bring lab manual, record and calculator.

2. All experimental data shall be recorded in the space provided under the heading ‘Observation’

in the laboratory manual.

3. The results and conclusion shall be reported in the lab manual and checked with the course

instructor before reporting it in the record.

4. The record shall be submitted in the next laboratory class.

5. Students without lab manual and/or completed record will not be permitted inside the

laboratory.

6. Attendance is compulsory in all labs. Only in case of emergency, the make-up lab will be

scheduled well in advance with the consent of faculty.

7. Performance of any unauthorized experiments is strictly forbidden in the laboratory.

8. Use of Cell phones, personal audio or video equipment is prohibited in the laboratory.

Lab safety

1. Wear a full-length, long-sleeved laboratory coat or chemical-resistant apron.

2. Wear shoes that adequately cover the whole foot; low-heeled shoes with non-slip soles are

preferable. Do not wear sandals, open-toed shoes, open-backed shoes, or high-heeled shoes in

the laboratory.

3. Secure loose clothing (especially loose long sleeves, neck ties, or scarves).

4. Do not wear dangling jewellery during lab hours.

5. Secure Long hair - Long hair can accidentally fall into flames or chemicals. Many hair sprays,

gels, mousses, etc. are flammable. Loose, long hair can also block your vision, which can lead

to accidents.

6. Never leave experiments while in progress.

7. Do not remove any equipment or chemicals from the laboratory.

8. Do not smell or taste any chemical in the laboratory.

9. Store coats, bags, and other personal items in designated areas.

10. Bring only the essentials to lab bench.

11. No eating, drinking, playing or applying cosmetics (including hand lotion, etc).

12. Handle glass wares cautiously. Never use broken or chipped glassware.

13. Do not pipette out acids and other toxic reagents by mouth.

Department of Civil Engineering – 15CVL76 xii


14. Always perform the experiments as directed by the course instructor.

15. Wash hands after contact with hazardous chemicals and before leaving the laboratory.

Lab Etiquette

1. Return all chemicals and supplies to the proper location after use.

2. Take chemicals from reagent bottles; pour out slightly more than the amount of chemical

needed into a clean beaker. Never pour a chemical back into a reagent bottle.

3. Clean up for the next person. At the conclusion of each work period, all used glassware must be

cleaned and set to drain.

4. Scrub inside of glassware with water and laboratory detergent, rinse with tap water, rinse with

distilled water, and place cleaned glassware on a rack to dry.

5. No experiment is complete until the laboratory is cleaned.

Department of Civil Engineering – 15CVL76 xiii


EVALUATION SHEET

SN Date Experiment Page

No.

Marks allotted

Total Faculty

Sign Conduction

(4)

Record

(4)

Viva

(4)

1 Determination of pH

2 Determination of Acidity

3 Determination of Alkalinity

4 Determination of Calcium,

Magnesium and Total Hardness

5 Determination of DO

6 Determination of BOD

7 Determination of Chlorides

8

Determination of percentage of

available chlorine in bleaching

powder

9 Determination of Residual

Chlorine

10 Determination of Solids in

Sewage

11 Determination of Turbidity

12 Determination of Optimum

Dosage of Alum

13 Determination of sodium

14 Determination of potassium

15 Determination Nitrates

16 Determination of Iron

17 Determination of Manganese

18 Determination of COD

19 Air Quality Monitoring (Demo)

20 Determination of Sound by

Sound level meter (Demo)

Average (A) -12

Internal Assessment Marks (B) - 08

Total Marks (A + B) -20

Department of Civil Engineering – 15CVL76 xiv


IMPORTANCE OF ENVIRONMENTAL ENGINEERING LAB

Two hydrogen atoms and one oxygen atom forms a molecule of water. This pure water is

practically impossible to have in nature or in laboratory. The precipitation, at the instant of its

formation contains no impurities, but during its course of reaching earth through the atmosphere,

dissolves many gases, mineral traces and other substances. Once it reaches the earth’s surface, the

rain water may get physically, chemically or biologically contaminated.

The impurities which the water picks up or dissolves may render the water more useful and

potable for public uses or it may sometimes render it harmful and unfit for further use. For example,

certain minerals such as iron, calcium, magnesium, fluorine, etc., in small quantities may be useful

and good for health of the people. But, if the same and other materials are in large quantities or

different combinations, the water might become unfit or municipal or industrial use. For example,

water may contain pathogenic bacteria, which may cause diseases like cholera, typhoid, dysentery,

etc. Thus, to ensure safety to public, economy and utility in industries, it is essential to thoroughly

check, analyse, and treat the raw available water to safe and permissible limits, before supplying to

the public, used for irrigation or in industries.

The raw or treated water can be checked and analysed by studying and testing their physical,

chemical and biological characteristics. Thus, the experiments conducted in Environmental

engineering laboratory helps us in determining the contents of water and waste water and thereby

help us to decide on the degree of treatment required.

Experiments such as conductivity, determination of chlorides etc. can be used to determine

the type of desalination unit required which can be employed in coastal areas, where, there is acute

shortage of drinking water. Experiments such as determination of chlorides, sulphates, acidity,

alkalinity, pH value helps us determine whether the given water is suitable for human consumption.

Department of Civil Engineering – 15CVL76 xv


The determination of hardness present in water is important in pharmaceutical and textile industries.

Determination of BOD is the one of the parameters that gives us an idea about the biodegradability

of any sample and the purification capacity of rivers and streams. The COD test is useful to assess

the strength of waste which contains toxins and biologically resistant organic substances.

The importance of each characteristic and its environmental significance is given in detail with the

experimental procedure.

To conclude, this laboratory provides us with the facilities required to assess the quality of

the raw and treated water and sewage, which is imperative to maintain the successful operation of

the treatment units along with safe supply of water to public and disposal into the environment.

COLLECTION AND PRESERVATION OF SAMPLES

SAMPLING:

SIGNIFICANCE OF SAMPLING:

The value of any laboratory analysis and tests depends upon the method of sampling.

Failure to observe proper precautions in securing a representative sample may result in an

analysis which is of little use since it may condemn good water or certify bad water as

satisfactory.

COLLECTION AND PRESERVATION OF SAMPLE:

Objective of sampling is to collect a representative sample

Representative sample means a sample in which relative proportions or concentration of all

relevant components will be same as in the material being sampled.

The sample should be handled in such a way that no significant change in composition occurs

before tests are made.

The volume of sample shall be such that it is small enough to be transported and large enough

for analysis.

In order to achieve accurate results, the sample collection, tracking of sample and preservation

techniques for storage of sample should be carried out appropriately.

Department of Civil Engineering – 15CVL76 xvi


GENERAL REQUIREMENTS FOR COLLECTION AND PRESERVATION OF

SAMPLES:

1. Obtain a sample that meets the requirements of the sampling program and handle it so that it

does not deteriorate or become contaminated before it is analyzed.

2. Ensure that all sampling equipment is clean and quality-assured before use. Use sample

containers that are clean and free of contaminants.

3. Depending upon type of analysis, fill the containers full (for most organic compound

determinations) or leave space for mixing, aeration, etc., (for most microbiological and inorganic

analysis)

4. Special precautions are necessary for samples containing organic compounds and trace metals as

they are present in very low concentrations and hence might be partially or totally lost during

sampling

5. Record of sample shall contain:

a. General information: sample identification number; location; name of sample collector; date

and time; sample type(grab/composite)

b. Specific information: water temperature; weather; stream flow; water level; any other

information

It can be attached as a tag, label or writing on container.

6. When samples are collected from river/stream, results may vary with depth, stream flow and

distance from each shore.

7. Selection of number of samples and site at which samples should be collected depends on study

objectives, stream characteristics, available equipments , etc.,

a. If equipment is available, take an integrated sample from top to bottom in the middle of main

channel of stream or from side-to-side at mid depth.

b. If only grab samples can be collected, take them at various points of equal distance across

the stream.

c. If only one sample can be collected, then take it in the middle of main channel of stream at

mid-depth.

Department of Civil Engineering – 15CVL76 xvii


TYPES OF SAMPLES

1. GRAB SAMPLES:

a. Grab samples are the samples collected at a specific spot at a site over a short period of time.

b. They represent a ‘snapshot’ in both time and space of a sampling area.

c. Discrete grab samples are collected at a selected location, depth and time.

d. Depth-integrated grab samples are collected over a pre-determined part of the entire depth of

water column, at a selected location and time in a given body of water.

e. It represents only the composition of its source at the time and place of collection.

f. Grab sampling is appropriate where conditions are constant, or well mixed and slow to

change.

2. COMPOSITE SAMPLES:

a. Composite samples provide a more representative sampling of heterogeneous matrices in

which the concentration of the analytes of interest may vary over short periods of time

and/or space.

b. Composite samples can be obtained by combining portions of multiple grab samples or by

using specially designed automatic sampling devices.

c. The simplest form is time-related composites, which are made up of sub-samples of equal

volume taken at specific time intervals.

d. The other form is flow proportional sampling, which uses a purpose-designed automatic

sampler. These units take samples of wastewater proportional to the flow and are usually

linked to an automatic flow meter.

3. INTEGRATED SAMPLES:

a. Integrated samples are a mixture of grab samples collected from different points

simultaneously and mixed in equal volumes.

b. The need for integrated samples may exist if a combined treatment is proposed for several

separate wastewater streams. As the interaction between these different wastewater steams

may have a significant effect on treatability.

Department of Civil Engineering – 15CVL76 xviii


SAMPLING METHODS

1. MANUAL SAMPLING:

It involves minimal equipment but maybe costly and time-consuming for routine or large scale

sampling.

Requires trained field technicians

Necessary for regulatory and research investigations for which critical understanding of field

conditions and complex sample collection techniques are essential.

2. AUTOMATIC SAMPLING:

Eliminates human errors which might occur in manual sampling

Reduces labour costs

More frequent sampling can be done

Care should be taken that the automatic sampler do not contaminate the sample

Programme the automatic sampler in accordance with sampling needs

3. SORBENT SAMPLING:

Use of solid sorbents, particularly membrane-type disks, is becoming more frequent.

Rapid, inexpensive method, if the analytes can be adsorbed and desorbed efficiently and the

water matrix is free of particulates that plug the sorbent.

Department of Civil Engineering – 15CVL76 xix


GENERAL INFORMATION

In water and wastewater analysis, the results are usually reported in terms of mg/L of a particular

ion, element or compound. It shall be convenient to have the standard titrating agent of such

strength, that 1mL is equivalent to 1mg of material being measured. Thus 1 litre of the standard

solution is usually equivalent to 1g of the standard substance.

Normality

The desired normality of the titrant is obtained by the relationship of 1 to the equivalent weight of

the measured material. Thus normality of acid solution to measure ammonia, ammonia nitrogen, and

alkalinity as CaCO3

Ammonia: = 1/eq. wt. = 1/17 = N/17 = 0.0588 N

Ammonia Nitrogen: = 1/eq. wt. = 1/14 = N/14 = 0.020 N

Alkalinity: = 1/eq. wt. = 1/50 = N/50 = 0.020 N

The normality of basic solution to measure mineral acidity as CaCO3 is:

Acidity: = 1/eq. wt. = 1/50 = N/50 = 0.020 N

The normality of silver nitrate to measure chloride and sodium chloride is:

Chloride: = 1/eq. wt. = 1/35.45 = N/35.45 = 0.0282 N

Sodium chloride: = 1/eq. wt. = 1/58.44 = N/58.44 = 0.071 N

Thus the substance measured is calculated as follows:

Most materials subjected to the analysis of water and wastewater fall in the realm of dilute solutions

i.e., a few mg in a litre. So the results are normally expressed in mg/L or ppm. Parts per million

(ppm) is a weight ratio; but mg/L is a weight by volume ratio.

The relationship is given as follows:

If concentrations are less than 0.1 mg /L, express them in μg/L (micrograms per litre).

If concentrations are more than 10,000 mg/L, they are expressed in percentages.

Department of Civil Engineering – 15CVL76 xx


QUALITY STANDARDS FOR MUNICIPAL OR DOMESTIC SUPPLIES

Water required for domestic uses, particularly the drinking water must be colourless, odourless and

tasteless. It should be free from turbidity, and excessive or toxic chemical compounds, harmful

micro-organisms and radio activity must be absent. Thus, the quality of water for municipal supplies

is controlled throughout the world. World health organisation (W.H.O.) has laid down its standards

for potable waters. Bureau of Indian Standards have formulated the Indian Standard Drinking water

specifications (1991), which today stand as our national drinking water standards. Essential

parameters are given below as taken from IS 10500:2012

Table: Indian standard drinking water specifications (IS 10500: 2012)

Table 1: Organoleptic and Physical Parameters

Sl

No. Characteristic

Requirem

ent Permissible

Method of

Test, Remarks

(Acceptabl

e Limit in the Ref to Part of

Limit) Absence of IS 3025

Alternate

Source

(1) (2) (3) (4) (5) (6)

i)

Colour, Hazen units,

Max 5 15 Part 4

Extended to 15 only, if toxic

substances are not suspected

in absence of alternate

sources

ii) Odour Agreeable Agreeable Part 5

a) Test cold and when

heated

b) Test at several dilutions

iii) pH value 6.5-8.5 No relaxation Part 11

—

iv) Taste Agreeable Agreeable Parts 7 and 8

Test to be conducted only

after safety has been

established

v) Turbidity, NTU,

Max 1 5 Part 10 —

vi) Total dissolved

solids, mg/l, Max 500 2 000 Part 16 —

Department of Civil Engineering – 15CVL76 xxi


NOTE — It is recommended that the acceptable limit is to be implemented. Values in excess of

those mentioned under ‘acceptable’ render the water not suitable, but still may be tolerated in the

absence of an alternative source but up to the limits indicated under ‘permissible limit in the absence

of alternate source’ in col 4, above which the sources will have to be rejected.

Table 2 General Parameters Concerning Substances Undesirable in

Excessive Amounts

Sl

No. Characteristic

Requirem

ent Permissible Method of Test, Remarks

(Acceptabl

e Limit in the Ref to

Limit) Absence of

Alternate

Source

(1) (2) (3) (4) (5) (6)

i)

Aluminium (as Al),

mg/l, Max 0.03 0.2

IS 3025 (Part

55) —

ii)

Ammonia (as total

ammonia-N), 0.5 No relaxation

IS 3025 (Part

34) —

mg/l, Max

iii)

Anionic detergents (as

MBAS) 0.2 1.0

Annex K of IS

13428 —

mg/l, Max

iv)

Barium (as Ba), mg/l,

Max 0.7 No relaxation

Annex F of IS

13428* —

or IS 15302

v)

Boron (as B), mg/l,

Max 0.5 1.0

IS 3025 (Part

57) —

vi)

Calcium (as Ca), mg/l,

Max 75 200

IS 3025 (Part

40) —

vii)

Chloramines (as Cl2),

mg/l, Max 4.0 No relaxation

IS 3025 (Part

26)* —

or APHA 4500-Cl G

viii)

Chloride (as Cl), mg/l,

Max 250 1 000

IS 3025 (Part

32) —

ix)

Copper (as Cu), mg/l,

Max 0.05 1.5

IS 3025 (Part

42) —

x)

Fluoride (as F) mg/l,

Max 1.0 1.5

IS 3025 (Part

60) —

xi)

Free residual chlorine,

mg/l, Min 0.2 1

IS 3025 (Part

26)

To be applicable

only when

water is chlorinated.

Tested

at consumer end.

When pro-

tection against viral

Department of Civil Engineering – 15CVL76 xxii


infec-

tion is required, it

should be

minimum 0.5 mg/l

xii) Iron (as Fe), mg/l, Max 0.3 No relaxation

IS 3025 (Part

53)

Total concentration

of man-

ganese (as Mn) and

iron (as

Fe) shall not exceed

0.3 mg/l

xiii)

Magnesium (as Mg),

mg/l, Max 30 100

IS 3025 (Part

46) —

xiv)

Manganese (as Mn),

mg/l, Max 0.1 0.3

IS 3025 (Part

59)

Total concentration

of man-

ganese (as Mn) and

iron (as

Fe) shall not exceed

0.3 mg/l

xv) Mineral oil, mg/l, Max 0.5 No relaxation

Clause 6 of IS

3025 —

(Part 39)

Infrared

partition

method

xvi)

Nitrate (as NO3), mg/l,

Max 45 No relaxation

IS 3025 (Part

34) —

xvii) Phenolic compounds (as C6H5OH), 0.001 0.002

IS 3025 (Part 43) —

mg/l, Max

xviii

)

Selenium (as Se), mg/l,


IS 3025 (Part

56) or —

IS 15303*

xix)

Silver (as Ag), mg/l,


Annex J of IS

13428 —

xx)

Sulphate (as SO4) mg/l,

Max 200 400

IS 3025 (Part

24)

May be extended to

400 pro-

vided that Magnesium does

not exceed 30

xxi)

Sulphide (as H2S), mg/l,


IS 3025 (Part

29) —

xxii) Total alkalinity as calcium 200 600

IS 3025 (Part 23) —

carbonate, mg/l, Max

xxiii

)

Total hardness (as

CaCO3), 200 600

IS 3025 (Part

21) —

mg/l, Max

xxiv

) Zinc (as Zn), mg/l, Max 5 15

IS 3025 (Part

49) —

Department of Civil Engineering – 15CVL76 xxiii


NOTES 1 In case of dispute, the method indicated by '*' shall be the referee method. 2 It is recommended that the acceptable limit is to be implemented. Values in excess of those

mentioned under ‘acceptable’ render the water not suitable, but still may be tolerated in the

absence of an alternative source but up to the limits indicated under ‘permissible limit in the

absence of alternate source’ in col 4, above which the sources will have to be rejected.

Department of Civil Engineering – 15CVL76 Page 24


WATER QUALITY CRITERIA AS PER CPCB NORMS

DESIGNATED BEST USE CLASS CRITERIA

OF

WATER

Drinking Water Source without A Total Coliforms Organism MPN/100ml shall be

conventional treatment but after 50 or less

disinfection pH between 6.5 and 8.5

Dissolved Oxygen 6mg/l or more

Biochemical Oxygen Demand 5 days 20°C

2mg/l or less

Outdoor bathing (Organised) B Total Coliforms Organism MPN/100ml shall be

500 or less

pH between 6.5 and 8.5



3mg/l or less

Drinking water source after conventional treatment and disinfection C

Total Coliforms Organism MPN/100ml shall be 5000 or less

pH between 6 to 9



3mg/l or less

Propagation of Wild life and D pH between 6.5 to 8.5 Dissolved Oxygen 4mg/l or more

Free Ammonia (as N) 1.2 mg/l or less

Irrigation, Industrial Cooling, E pH between 6.0 to 8.5

Controlled Waste disposal Electrical Conductivity at 25°C micro mhos/cm

Max.2250

Sodium absorption Ratio Max. 26

Boron Max. 2mg/l



WATER TREATMENT PLANT- FLOWCHART

Typical water treatment flowchart: Raw water from a surface water lake or reservoir is drawn into

the plant through intake structures. Large debris like logs is prevented from entering. Smaller debris

like fish, vegetation and garbage are removed from the raw water by protective bar and travelling

screens before the water enters the low lift pumps. These pumps lift the water to flow through the

treatment processes by gravity. First, pre-oxidation and primary disinfection is done, where

Disinfectants or other oxidants are added to disinfect or control tastes and odours. The specific

processes used are determined by the chemical and biological raw water characteristics. Next during

coagulation, coagulants, rapidly add electrochemical charges that attract the small particles in water to

clump together as a “floc”. This initial charge neutralization process allows the formed floc to

agglomerate but remain suspended. During flocculation, by slower mixing, turbulence causes the

flocculated water to form larger floc particles that become cohesive and increase in mass. This visible

floc is kept in suspension until large enough to settle under the influence of gravity.



Flocculated water is applied to large volume tanks (sedimentation) where the flow speed slows down

and the dense floc settles. Settled floc is removed and treated as a waste product that is discharged to

the sewer system. Relatively floc free, settled water flows through a media filter by gravity. Filter

media are made from layers of anthracite or granular activated carbon and sand. Gravel or synthetic

materials support the media. Physical straining removes the remaining floc. Filters are periodically

backwashed to clean off accumulated floc and other trapped impurities. Filtered water in the clear well

is used to backwash filters and kept in storage to ensure that disinfectants are in contact with the water

long enough to inactivate disease causing organisms. Supplemental chlorine is added to maintain

disinfection concentrations while the water is pumped through the distribution system. The purpose is to

ensure minimum residual disinfectant levels at the farthest points of the system. Next, optional

treatments required for special conditions, which can be decided based on characteristics of water can

be given. For example, here, Fluoridation is being carried out, which is a process where silicofluoride

compounds are added to treated drinking water to artificially raise the fluoride concentration to within a

specified range; for example between 0.5 to 0.8 mg/L (ppm). Treated drinking water is pumped through

large pressure pumps to other pumping stations, reservoirs or points of supply within the local

distribution system. Water distributed to water towers and storage reservoirs ensures stable water

pressure. An adequate supply of water is maintained to meet peak water demands or emergencies such

as fires, water main breaks, power outages and pump failures. Distribution systems are comprised of

large pipes known as trunk mains to deliver drinking water. Smaller diameter branch mains feed

individual streets. Service connections to branch mains deliver water into residences. Pumping stations

are used to increase pressure and to maintain adequate supply flows.



WASTE WATER TREATMENT PLANT- FLOWCHART

The selection of unit operations and unit processes for the treatment of sewage depends on

several factors such as characteristics of raw sewage, degree of purification required, disposal

facilities available, cost involved including cost of installation, maintenance and operation, ease of

construction and maintenance, benefits derived from better environmental sanitation, location,

availability of land and topographical conditions.

Typically, there are four stages of sewage treatment:

1. Sewage treatment begins with preliminary treatment, which involves removal of floating

material, settleable inorganic solids like sand and oily substances like grease. Equipments like

screens, grit chambers and skimming tanks are used to aid in removal of above impurities.

2. In the next stage, primary treatment is aimed at the removal of fine suspended organic solids that

cannot be removed in the preliminary treatment. Primary treatment basically involves the process of

sedimentation or settling. In the normal process of sewage treatment, sedimentation is usually carried

out twice- once before the secondary treatment, referred to as primary sedimentation, and then after



the secondary treatment is complete, a process known as secondary sedimentation. It is sometimes

necessary to use chemical coagulants to facilitate or aid sedimentation, and this process is referred to

as chemical precipitation or coagulation-aided sedimentation.

3. The third stage of sewage treatment is called secondary or biological treatment. Biological

treatment of sewage is required for the removal of dissolved and fine colloidal organic matter. This

process involves the use of microorganisms (bacteria, algae, fungi, protozoa, rotifers, nematodes)

that decompose the unstable organic matter to stable inorganic forms. The biological treatment

processes of sewage are broadly classified as aerobic, anaerobic and pond processes. Depending on

the nature of the use of the microorganisms, the biological processes are categorized as suspended

growth systems and attached growth systems.

The most important suspended-growth biological treatment systems used for the removal of organic

matter are:

1. Activated sludge process

2. Aerated lagoons

3. Sequencing batch reactor

4. Aerobic digestion.

Among these, activated sludge process is the most widely used for the secondary treatment of

sewage.

The commonly used attached-growth processes are listed:

1. Trickling filters

2. Roughing filters

3. Rotating biological contractors

4. Packed bed reactors.

Among these, trickling filter is most widely used.

4. Next, tertiary treatment or advanced treatment is sometimes needed for the removal of suspended

and dissolved substances, after the conventional primary and secondary treatments. In general, the

effluent of the sewage obtained after secondary treatment can be conveniently disposed without

causing any nuisance.

However, tertiary treatment is needed under the following circumstances:

1. When the quality of the effluent to be discharged does not meet the standard requirements.

2. When there is a necessity to reuse the sewage/ waste water (reclamation of water is quite

expensive, but is required in certain situations of water shortage).

3. For the removal of nitrogen and phosphorus compounds.

Tertiary treatment process broadly involves the removal of suspended and dissolved solids, nitrogen,

phosphorus and pathogenic organisms.



In the conventional hierarchy of sewage treatment, the unit operations are carried out in the order of

preliminary, primary, secondary and finally tertiary treatment. However, sometimes advanced

(tertiary) treatment process may be directly carried out bypassing the other unit operations. This

mainly depends on the composition of waste water and the requirements.

With this brief understanding on water and waste water treatment plant, let us start with the

experiments essential for analysing the quality of water/ wastewater.



EXPERIMENT 01 DATE: _________

DETERMINATION OF pH OF WATER

Aim: To determine the pH of the given sample of water using 1) pH paper, and 2) digital pH meter.

Introduction:

pH is the term used to express the acidic or alkaline condition of a solution. It expresses

hydrogen-ion concentration in water and concept of pH was put forward by Sorenson (1909). Acids

and bases were originally distinguished by their difference in taste and later by the manner in which

they affected certain materials that came to be known as indicators. With the discovery of hydrogen,

it soon became apparent that all acids contained the element hydrogen. Chemists found that

neutralization reactions between acids and bases always produced water. From this and other related

information, it was concluded that bases contained hydroxyl groups.

In 1887, Arrhenius announced his theory of ionization. Since that time acids have been considered to

be substances that dissociate to yield hydrogen ions or protons, and bases have been considered to be

substances that dissociate to yield hydroxide ions (also called hydroxyl ions). According to the

concepts of Arrhenius, strong acids and bases are highly ionized and weak acids and bases are poorly

ionized in aqueous solution.

The pure water dissociates to yield a concentration of hydrogen ions equal to about 10–7 mol/l.

H2O H+ + OH

–

The amount of hydroxyl ions is equal to the hydrogen ions, so 10–7

mol of hydroxyl ion is produced

simultaneously. The equilibrium equation gives

{H+} {OH

–}/H2O = K

As the concentration of water is so extremely large and is diminished so much little by the slight

degree of ionization it may be considered as constant and the above equation can be written as:

{H+} {OH

–} = Kw

For pure water at 25oC,

{H+} {OH

–} = 10

–7 × 10

–7 = 10

–14

This is known as the ion product or ionization constant for water. When an acid is mixed in water it

ionizes in the water and the H+ ion activity increases. Consequently the OH

- ion activity must

decrease according to the ionization constant.



For example, if acid is added to increase the {H+} to 10

–2, the {OH

–} must decrease to 10

–12

10–2

× 10–12

= 10–14

Similarly if a base is added to increase the {OH–} to 10

–3, the {H

+} decreases to 10

–11. However the

{H+} or the {OH

–} can never be reduced to zero no matter how basic or acidic the solution may be.

Designating the hydrogen ion concentration in terms of molar concentration is cumbersome and to

overcome this difficulty, Sorenson gave such value in terms of their negative logarithms as pH. So,

pH = – log {H+}

Or pH = log 1/ {H+}

The pH scale is represented as ranging from 0 to 14 with pH 7 at 25oC designating absolute

neutrality. pH lesser than 7 is acidic and more than 7 is a basic solution. pH is used in the calculation

of carbonate, bicarbonate and CO2, corrosion and stability index etc. While the alkalinity or acidity

measures the total resistance to the pH change or buffering capacity, the pH gives the hydrogen ion

activity.

Image source: United States Environmental Protection Agency



Principle:

pH can be measured colorimetrically or electrometrically. Colorimetric method is used only

for rough estimation. It can be done either by using universal indicator or by using pH paper. The

hydrogen electrode is the absolute standard for the measurement of pH. They range from portable

battery operated units to highly precise instruments. But glass electrode is less subjected to

interferences and is used in combination with a calomel reference electrode. This system is based on

the fact that a change of 1 pH unit produces an electric charge of 59.1 mV at 25°C.

The basic principle of electrometric pH measurement is determination of activity of hydrogen ions by

potentiometric measurements using a glass electrode. Contact between the test solution and electrode

is achieved by means of a liquid junction. The electromotive force is measured with a pH meter, that

is high impedance voltmeter calibrated in terms of pH.

Apparatus:

1) pH paper method: pH paper

2) Electrometric method: The apparatus consists of a pH meter with glass and reference electrode

with temperature compensation. The pH meter contains a glass electrode which generates a potential

varying linearly with the pH of the solution in which it is immersed. A calomel or Ag/AgCl/KCl

reference electrode is generally located around the glass electrode stem.

Procedure:

1) Using pH Papers

1. Dip the pH paper in the sample.

2. Compare the colour with that of the colour given on the wrapper of the pH paper book.

3. Note down the pH of the sample along with its temperature.

2) Electrometric Determination of pH

1. Dip the electrode in the buffer solution of known pH.

2. Switch on the power supply and take the reading. Standardize the instrument using the calibrating

knob.

3. After cleaning, again dip the electrodes in the buffer solution of pH 7. Note the reading. If it is

7, the instrument is calibrated. If not, correct the value and is manipulated so that the reading in

the dial comes to 7.0



4. A solution whose pH is to be found is taken in a beaker and the temperature knob is adjusted such

that the temperature of solution is same as that in dial.

5. The electrode is washed with distilled water and reused with the solution and then it is dipped in

the solution.

6. The reading on the dial indicates the pH of the solution.

Observations:

SN Sample pH with pH Paper pH with pH meter

1 A

2 B

3 C

Results:

The pH values of the given samples are as follows.

A :

B :

C :

Discussion:

Environmental Significance:

pH is important in almost every phase of environmental engineering and science.

The acceptable value of pH for potable water is 7.0 to 8.5.

Higher value of pH accelerates the scale formation in water heating apparatus and the boilers.

Higher values of pH reduce the germicidal potential of Chlorine.

pH value below 6.5 starts corrosion in pipes thereby releasing toxic metals like Zn.

In the field of water supplies, it is a factor that must be considered in chemical coagulation,

disinfection, water softening, and corrosion control.

In wastewater treatment employing biological processes, pH must be controlled within a range

favourable to the particular organisms involved. In biological treatment of waste waters if the pH

goes below 5 the decomposition is severely affected. There is a suitable range of 5 to 10 pH for

aerobic decomposition of organic matter present in the waste waters. If the pH is beyond

this range then it has to be adjusted by addition of acid or alkali.



Chemical processes used to coagulate wastewaters, dewater sludges, or oxidize certain

substances, such as cyanide ion, require that the pH be controlled within rather narrow limits.

The efficiency of the chemical coagulant like alum depends upon the pH of water and it is most

efficient in the pH range of 6.5 to 8.5.

Similarly chlorine is added to water to kill the bacteria and other microorganism and this process

is known as disinfection. The efficiency of chlorine is also dependent on the pH of water. So the

determination and then the required adjustment of pH is a must for the efficient use of coagulant

and disinfectants.

For these reasons and because of the fundamental relationships that exist between pH, acidity,

alkalinity, and chemical speciation in general, it is important to understand the theoretical as well as

the practical aspects of pH.

Questions:

1. pH is defined as

(i) Logarithm of Hydrogen ions (ii) Negative logarithm of Hydrogen ions

(iii) Hydrogen ion concentration (iv) OH ion concentration

2. For pure water at 25°C, the product of H+ and OH

– ions is

(i) 10–7

(ii) 10–14

(iii) 10 (iv) 107

3. The acceptable value of pH of potable water is

(i) 7.0 to 8.5 (ii) 6.5 to 9.5 (iii) 6 to 8.5 (iv) 6.5 to 10

4. The alum is most effective as a coagulant in the pH range of

(i) 6.5 to 8.5 (ii) 6 to 9.0 (iii) 6.5 to 9.5 (iv) 7.0 to 7.5

5. Discuss the relationship between (a) pH and hydrogen ion concentration (b) pH and hydroxide

ion concentration?

6. A decrease in pH of 1 unit represents how much of an increase in hydrogen ion concentration?

7. Why is it necessary to maintain the pH of water nearly 7?

8. What is a buffer solution? Give examples.

Marks Obtained:

Signature of Course Co-ordinator




DETERMINATION OF ACIDITY OF WATER

Aim: To determine the acidity of the given sample of water.

Introduction:

Acidity of water is its quantitative capacity to neutralise a strong base to a designated pH and

an indicator of how corrosive water is. In other words, acidity is the measure of ability of water to

neutralize bases. Acidity can be caused by weak organic acids, such as acetic and tannic acids, and

strong mineral acids including sulphuric and hydrochloric acids; however, the most common source

of acidity in unpolluted water is carbon dioxide in the form of carbonic acid.

Carbon dioxide is a normal component of all natural waters. It may enter surface waters by

absorption from the atmosphere, but only when its concentration in water is less than that in

equilibrium with carbon dioxide in the atmosphere, in accordance with Henry's law. Groundwater

and waters from the hypolimnion of stratified lakes and reservoirs often contain considerable

amounts of carbon dioxide. This concentration results from bacterial oxidation of organic matter with

which the water has been in contact, and under these conditions, the carbon dioxide is not free to

escape to the atmosphere. Carbon dioxide is an end product of both aerobic and anaerobic bacterial

oxidation; therefore, its concentration is not limited by the amount of dissolved oxygen originally

present. Mineral acidity is present in many industrial wastes, particularly those of the metallurgical

industry and some from the production of synthetic organic materials. Certain natural waters may

also contain mineral acidity. The drainage from abandoned mines and lean ore dumps will contain

significant amounts of sulphuric acid or salts of sulphuric acid if sulphur, sulphide, or iron pyrite are

present.

Principle:

Acidity is classified by the pH value of a titration end point. Hydrogen ions present in a

sample as a result of dissociation or hydrolysis of solutes are neutralised by titration with standard

alkali (NaOH here). Standard Methods for the Examination of Water and Wastewater (Standard

Methods) recommends titration with sodium hydroxide to an end point pH of 3.7 to determine

mineral acidity and titration to pH 8.3 to determine total acidity. Acidity is commonly determined

using methyl orange as a colour indicator of the pH end point. Because methyl orange undergoes a



colour change from red to orange at a pH of 3.7, the result of the titration is termed methyl orange

acidity.

Total acidity includes acidity caused by mineral acids, weak organic acids, and carbon dioxide (in the

form of carbonic acid). Acidity determined by titrating to a phenolphthalein end point pH of 8.3

corresponds to the neutralization of carbonic acid to bicarbonate. Note that carbon dioxide is the

major cause of acidity in natural waters, and thus, in most cases the phenolphthalein acidity is equal

to the total acidity. Methyl orange acidity and phenolphthalein acidity are the terms used to describe

the results. Results of the acidity tests are reported in mg/L CaCO3.

Sampling and storage:

Collect samples in polyethylene or borosilicate glass bottles and store at a low temperature. Fill

bottles completely and cap tightly. As wastewater samples may be subject to microbial action and to

loss or gain of CO2 or other gases when exposed to air, analyze samples without delay, preferably

within one day. If biological activity is suspected analyze within 6 hours. Avoid sample agitation and

prolonged exposure to air.

Apparatus:

1. Burette 2. Pipette 3. Erlenmeyer flasks 4. Indicator solutions

Reagents:

Titrant- Standard Sodium Hydroxide Solution - 0.02 N.

Methyl Orange Indicator solution – pH 3.7 indicator.

Phenolphthalein Indicator solution – pH 8.3 indicator.

Procedure: A. Methyl Orange Acidity:

1. Take 25 ml of the given sample in a conical flask.

2. Add 2 to 3 drops of methyl orange indicator.

3. If the sample turns to yellow colour on addition of methyl orange indicator, it implies that

there is no Partial acidity.

4. If the sample turns to orange colour, it means mineral acidity is present. Then, titrate the

sample with 0.02 N NaOH till the solution turns yellow in colour, indicating the end point.

5. Record the volume of titrant consumed in ml.

B. Phenolphthalein acidity:

1. Take 25 ml of the given sample in a conical flask.

2. Add few drops of phenolphthalein indicator.

3. If the solution turns to pink in colour, it indicates that acidity is absent in the sample.



4. If the solution does not give any colour (i.e. acidity is present), titrate with 0.02 N NaOH till

the solution turns pink, indicating end point.

5. Record the volume of titrant consumed in ml.

Observation:

Calculation:

1. Methyl Orange acidity in mg/L as CaCO3 =

2. Phenolphthalein acidity in mg/L as CaCO3 =

Where,

V = mL of NaOH titrant consumed

N = Normality of NaOH

SN Experiment Description of

sample(volume)

Initial Burette

reading

Final Burette

Reading

Volume of 0.02N

NaOH used

1. Methyl Orange

acidity

2. Phenolphthalein

acidity



Result:

1. Methyl Orange Acidity in mg/L as CaCO3 = ………………………

2. Phenolphthalein acidity in mg/L as CaCO3 = ………………………….

Discussion:


Acids contribute to corrosiveness and influence chemical reaction rates, chemical speciation and

biological processes.

Acid waters are of concern because of their corrosive characteristics and the expense involved in

removing or controlling the corrosion-producing substances. The corrosive factor in most waters

is carbon dioxide, but in many industrial wastes it is mineral acidity.

Where biological processes of treatment are used, the pH must ordinarily be maintained within

the range of 6 to 9.5. This criterion often requires adjustment of pH to favourable levels, and

calculation of the amount of chemicals needed is based upon acidity values in most cases.

Carbon dioxide determinations are particularly important in the field of public water supplies. In

the development of new supplies, it is an important factor that must be considered in the

treatment method and the facilities needed.

Many underground supplies require treatment to overcome corrosive characteristics resulting

from carbon dioxide. The amount present is an important factor in determining whether removal

by aeration or simple neutralization with lime or sodium hydroxide will be chosen as the

treatment method. The size of equipment, chemical requirements, storage space, and cost of

treatment all depend upon the amounts of carbon dioxide present.

Carbon dioxide is an important consideration in estimating the chemical requirements for lime or

lime-soda ash softening.

Most industrial wastes containing mineral acidity must be neutralized before they may be

discharged to rivers or sewers or subjected to treatment of any kind. Quantities of chemicals,

size of chemical feeders, storage space, and costs are determined from laboratory data on acidity.



Questions:

1. Acidity of water means

a. pH of water in acidic range

b. pH of water in alkaline range

c. base neutralizing capacity of water

d. acid neutralizing capacity of water

2. What pH range is used to measure mineral acidity in water? ___________

3. What pH range is used to measure total acidity in water? _______________

4. Discuss the source and nature of acidity.

5. Discuss the significance of carbon dioxide and mineral acidity.

6. Can the pH of a water sample be calculated from knowledge of its acidity? Why?

7. A water sample has a methyl orange acidity of 60 mg/L. Calculate the quantity of lime in

mg/L of Ca(OH)2 required to raise the pH to 3.7?

8. Estimate the carbon dioxide content of a natural water sample having a pH of 7.3 and a

bicarbonate-ion concentration of 30 mg/L. Assume that the effect of the dissolved solids on

ion activity is negligible and the water temperature is 25°C.

9. A water supply was found to have a bicarbonate-ion concentration of 50 mg/L and a C02

content of 30 mg/L. Estimate the approximate pH of the water (temperature equals 25°C).

10. If the C02 content of the water in Q. 10 were reduced to 3 mg/L by aeration, what would the

pH then be?

11. What are the sources of mineral acidity in water?

12. The permissible limit for total acidity as CaCO3 in water used for RCC works should not be

more than …………………..mg/l.

Marks Obtained:





DETERMINATION OF ALKALINITY OF WATER

Aim: To determine the amount of the following types of alkalinity present in the given samples:

a. Hydroxide alkalinity

b. Carbonate alkalinity

c. Bicarbonate alkalinity

Introduction:

Alkalinity of water is a measure of its capacity to neutralize acids. It is primarily due to salts of

weak acids, although weak or strong bases may also contribute. Alkalinity is significant in many

uses and treatments of natural waters and wastewaters. Because the alkalinity of many surface waters

is primarily a function of carbonate, bicarbonate, and hydroxide content, it is taken as an indication

of the concentration of these constituents.

It is expressed in terms of CaCO3 equivalent to hydrogen ions neutralized. The major portion of

alkalinity in natural water is caused by carbonates, bicarbonates and hydroxides which may be

ranked in order of their association with high pH values.

Highly alkaline water leads to caustic embrittlement and causes deposition of precipitates and boiler

tubes. Bicarbonates of calcium and magnesium include temporary hardness to water. Boiler water

always contains carbonates and hydroxide alkalinity, chemically treated water (lime or lime soda

ash softening water) will be alkaline due to the presence of carbonates and excess hydroxide. High

alkalinity in natural water will favour the growth of algae and phytoplankton. Principle:

Hydroxyl ions present in a sample as a result of dissociation or hydrolysis of solutes react

with standard acid added. Alkalinity thus depends on the end-point pH used.

Alkalinity is usually imparted by bicarbonate, carbonate and hydroxide. It is measured volumetrically

by titration with 0.02 N sulphuric acid and is reported in terms of CaCO3 equivalent. For samples

whose initial pH is above 8.3, the titration is conducted in two steps. In the first step, the titration is

conducted until the pH is lowered to 8.2, the point at which phenolphthalein indicator turns from

pink to colourless. This value corresponds to the points for conversion of carbonate to bicarbonate

ion. The second phase of titration is conducted until the pH is lowered to 4.5, corresponds to methyl

orange end point, which corresponds to the equivalence points for the conversion of bicarbonate ion

to carbonic acid.



Titration to decolourisation of phenolphthalein indicator will indicate complete neutralization of

OH- and ½ of CO3

- while sharp change from yellow to orange of methyl orange indicator indicates

total alkalinity (complete neutralization of OH-, CO3

- , HCO3)

The equation in its simplest form is as follows:

CO32-

+ H+ = HCO3 (pH 8.3)

From pH 8.3 to 3.7 the following reaction may occur:

HCO3−

+ H+ = H2CO3

Sampling and storage:

Collect samples in polyethylene or borosilicate glass bottles and store at a low temperature. Fill

bottles completely and cap tightly. As wastewater samples may be subject to microbial action and to

loss or gain of CO2 or other gases when exposed to air, analyze samples without delay, preferably

within one day. If biological activity is suspected analyze within 6 hours. Avoid sample agitation and

prolonged exposure to air.

Apparatus:

1. Burette 2. Pipette 3. Erlenmeyer flasks 4. Indicator solutions Reagents:

1. Standard Sulphuric Acid ( 0.02 N) 2. Phenolphthalein indicator

3. Methyl orange indicator

Procedure: Phenolphthalein Alkalinity:

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

2. Add 3-4 drops of phenolphthalein indicator. If the pH of sample is above 8.3, sample turns

pink.

3. Titrate with 0.02 N H2SO4 in a burette till the colour disappears.

4. Note down the volume of H2SO4 added (V1) Total Alkalinity:

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

2. Add 3-4 drops of Methyl orange indicator. The sample turns yellow.

3. Titrate it against 0.02N H2SO4 till the colour of the sample turns orange.

4. Note down the total volume of H2SO4 added (V2)



Observation:

Calculation:

1. Phenolphthalein alkalinity (P) as mg/L CaCO3 =

2. Total alkalinity (T) as mg/L CaCO3 =

Where,

V = mL of H2SO4 titrant consumed

N = Normality of H2SO4

The types of alkalinities present in the samples are calculated using the equations given in the

following table and the results are tabulated.

Result of titration Hydroxide alkalinity

as CaCO3

Carbonate alkalinity

as CaCO3

Bicarbonate

alkalinity as CaCO3

P=0 0 0 T

P < ½ T 0 2P T-2P

P = ½ T 0 2P 0

P > ½ T 2P-T 2(T-P) 0

P = T T 0 0

SN Experiment Description of

sample(volume)

Initial Burette

reading

Final Burette

Reading

Volume of 0.02N

H2SO4 used

1. Phenolphthalein

alkalinity

2. Total Alkalinity



Result:

1. Phenolphthalein alkalinity in mg/L as CaCO3 = ………………………

2. Total alkalinity in mg/L as CaCO3 = ………………………….

3. Hydroxide Alkalinity (mg/lt) = …………………………

4. Carbonate Alkalinity (mg/lt) = …………………………

5. Bicarbonate Alkalinity (mg/lt) = ………………………….

Discussion:

Environmental Significance: Highly alkaline water in usually unpalatable and the consumer tends to seek other supply.

Chemically treated water sometimes has rather high pH values which have met with some

objection by consumers.

Large amounts of alkalinity impacts bitter tastes to water.

Chemicals used for coagulation of water and wastewater react with water to form insoluble

hydroxide precipitates. The hydrogen ions released react with the alkalinity of the water. Thus,

the alkalinity acts to buffer the water in a 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.

Water softening: To find out quantity of lime and soda ash required for the removal of hardness,

alkalinity should be computed.

Alkalinity aids in corrosion control.

Buffer Capacity: | Alkalinity measurements are made as a means of evaluating the buffering

capacity of wastewaters and sludges. They can also be used to assess a natural water’s ability to

resist the effects of acid rain.

Influence of waste water: waste water containing excess caustic (hydroxide) alkalinity is not to

be discharged into natural water bodies or sewers. Excess alkalinity in water is harmful for

irrigation which reduces crop yield. Alkalinity less than 250 mg/L is desirable for domestic

consumption and RCC Works.



Alkalinity in excess of alkaline earth metal concentrations is significant in determining the

suitability of a water for irrigation. Alkalinity measurements are used in the interpretation and

control of water and wastewater treatment processes.

Many regulatory agencies prohibit the discharge of wastes containing caustic (hydroxide)

alkalinity to receiving waters, Municipal authorities usually prohibit the discharge of wastes

containing caustic alkalinity to sewers. Alkalinity as well as pH is an important factor in

determining the amenability of wastewaters to biological treatment.

Questions:

1. What is meant by alkalinity in water and waste water.

2. 2000ml of a sample of water required 20 ml of N/50 H2SO4 using methyl orange as indicator but

did not produce any coloration with phenolphthalein. What type of alkalinity is present in the

sample?

3. What effect does the addition of carbon dioxide have on the total alkalinity of water?

4. On analysis, a series of samples was found to have the following pH values: 5.5,3.0, 11.2, 8.5,

7.4, and 9.0. What can you conclude regarding the possible presence of a significant bicarbonate,

carbonate, or hydroxide alkalinity in each sample?

5. What causes alkalinity in water?

6. At what pH range alkalinity is present in water?

7. How alkalinity is removed from water?

8. What is the permissible limit of alkalinity in drinking water?

9. Which is the major form of alkalinity? How is it formed?

10. What is excess alkalinity? How do you express it?

11. Why do we take 0.02 N H2SO4 for the titration?

12. Calculate the Phenolphthalein and total alkalinities of the following samples: (a) A 50-mL

sample required 5.3 mL 0.020 N H2S04 to reach the Phenolphthalein end point and a total of 15.2

mL to reach the methyl orange end point. (b) A 100-mL sample required 20.2 mL of 0.020 N

H2S04 to reach the Phenolphthalein end point and a total of 25.6 mL to reach the methyl orange

end point.

13. The water where algae are flourishing is alkaline. Why? Will there be diurnal variation in pH?

14. Why does the pH change on aerating the water?

15. For efficient coagulation the water must be alkaline. Why?



16. Alkalinity is normally measured in terms of CaC03. What is the formula weight of this

compound? In what way might this formula weight make CaC03 a convenient reference material

for alkalinity?

17. Calculate the alkalinity as CaC03 of water that contains 85 mg/L of HCO3-, 120 mg/L of CO3

2-,

and 2 mg/L of OH-.

18. What effect does the removal of carbon dioxide from water through aeration have on each of the

three kinds of alkalinity found present in natural waters?

Marks Obtained:





DETERMINATION OF TEMPORARY HARDNESS, PERMANENT

HARDNESS AND TOTAL HARDNESS Aim: To determine total hardness, temporary hardness and permanent hardness of a given sample

using titrimetric method.

Introduction:

Originally, the hardness of water was understood to be a measure of the capacity of water for

precipitating soap. Soap is precipitated chiefly by the calcium and magnesium ions commonly

present in water, but may also be precipitated by ions of other polyvalent metals, such as aluminium,

iron, manganese, strontium and zinc, and by hydrogen ions. As the first two are usually present in

insignificant concentrations in natural waters, hardness is defined as a characteristic of water, which

represents the total concentration of just the calcium and the magnesium ions expressed as calcium

carbonate.

If bicarbonates, carbonates of Calcium and Magnesium are present in water, the water is rendered

hard temporarily as the hardness can be removed to some extent by simple boiling or to full extent

by adding lime to water. Such hardness is known as temporary hardness when water is boiled CO2

gas is liberated out and the insoluble calcium carbonate being fairly soluble in water will not be

removed by boiling. It causes deposition of scales in boilers.

On the other hand when sulphates, chlorides and nitrates of calcium or magnesium are present in

water, they cannot be removed by simple boiling and therefore requires special treatment for

softening. Such hardness is known as permanent hardness.

Hard waters are undesirable because they may lead to greater soap consumption, scaling of boilers,

causing corrosion and incrustation of pipe making food tasteless etc.

Unit of hardness is usually expressed in terms of “ppm” (parts per million) or mg/L of CaCO3 in

water. Scale of hardness from consumer point of view is given below:

Water Classification Total hardness concentration in

(mg/L) as CaCO3

Soft 0-50

Moderately Soft 50-100

Slightly hard 100-150

Moderately hard 150-200

Hard 200-300

Very hard >300



Hardness test of water is important in determining suitability of water for domestic and industrial

use. Also the determination of hardness serves as a basis for finding the most economical method

of softening water.

Principle:

When the hardness is numerically greater than the sum of the carbonate alkalinity and the

bicarbonate alkalinity, the amount of hardness, which is equivalent to the total alkalinity, is called

carbonate hardness; the amount of hardness in excess of this is called non-carbonate hardness.

When the hardness is numerically equal to or less than the sum of carbonate and bicarbonate

alkalinity all of the hardness is carbonate hardness and there is no noncarbonate hardness. The

hardness may range from zero to hundreds of milligrams per litre in terms of calcium carbonate,

depending on the source and treatment to which the water has been subjected.

Ethylenediamine tetra-acetic acid and its sodium salts (EDTA) form 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 is added to an aqueous solution containing calcium and magnesium ions at a pH

of 10 ± 0.1, the solution will become wine red. Then when the solution is titrated against EDTA, it

forms complex with the calcium and magnesium ions. After sufficient EDTA has been added to

complex all the magnesium and calcium, the solution will turn back from wine red to blue. This is

the end point of the titration.

Reagents:

1. Hardness Buffer Solution

2. Eriochrome Black T indicator

3. Standard EDTA Solution 0.01M

Apparatus:

1. Burette; 2. Pipette; 3. Conical Flask

Procedure:

1. Take 25 ml sample in a conical flask.

2. Add 1 ml of Hardness buffer solution.

3. Add 2-3 drops of Eriochrome Black T indicator. Wine red colour is observed.

4. Titrate with standard EDTA solution till wine red colour changes to blue.

5. Note down the volume of EDTA run down (A)



6. For determination of permanent hardness, sample should be boiled for 30 minutes, and

cooled. The sample procedure is followed as above. The volume of EDTA run down

is noted (B).

Observations:

Total Hardness:

Calculations:

Total hardness as mg/L CaCO3 =

Where,V = Volume of EDTA

Permanent Hardness:

Permanent hardness as mg/L CaCO3 =

Where, V = Volume of EDTA

Temporary Hardness = (Total hardness – Permanent hardness) = ……………….. as CaCO3

SN Description of

sample(volume)

Initial Burette

reading

Final Burette

Reading Volume of EDTA (mL)

SN Description of

sample(volume)

Initial Burette

reading

Final Burette




DETERMINATION OF CALCIUM AND CALCIUM HARDNESS: Burette: 0.01M. EDTA

Conical flask: 25 ml of sample + 2 ml NaOH (1N.)

Indicator: Muroxide / Ammonium Purpurate

End point: Pink to Purple

Calculations:

Calcium hardness as mg/L CaCO3 =

Where,V = Volume of EDTA

Calcium Hardness = ………………………… as CaCO3

Calcium as mg/L =

Calcium = ………………

SN Description of

sample(volume)

Initial Burette

reading

Final Burette




DETERMINATION OF MAGNESIUM AND MAGNESIUM HARDNESS

Magnesium Hardness = Total Hardness – Calcium Hardness

Magnesium in mg/lt. = Magnesium Hardness x 0.243 Results:

1. Total hardness = ………………….mg/L as CaCO3

2. Permanent hardness = …………….. mg/L as CaCO3

3. Temporary hardness = ...…………. mg/L as CaCO3

4. Calcium Hardness = ………………. mg/L as CaCO3

5. Magnesium Hardness = ………………. mg/L as CaCO3

6. Calcium = ………..mg/L

7. Magnesium = ………..mg/L

Discussion:

Environmental Significance: Advantages:

Absolutely soft water is tasteless. Eg: Distilled water.

Moderate hard water is preferred to soft water for irrigation purpose.

Scales are formed on inner coating of pipelines and hence prevent corrosion.

Absolutely soft water is corrosive and dissolves metals.

More cases of cardiovascular diseases are reported in soft waters.

Hard water is useful to growth of children due to presence of calcium.



Disadvantages:

Hard water causes excessive consumption of soap user for cleaning purposes.

Scales formed act as insulation in case of pipelines and cause enormous loss in boilers.

Scales formed in distribution mains reduce their carrying capacity.

Magnesium hardness (associated with sulphate ions) has a laxative effect on persons

unaccustomed to it.

Makes food tasteless.

Questions:

1. What is degree of hardness? How will you classify water in terms of degree of hardness?

2. What is pseudo-hardness?

3. Explain the significance of determination of hardness of water in environmental engineering.

4. How can you remove permanent hardness from water?

5. Can you determine temporary hardness and permanent hardness separately? If yes, how?

6. What are the principal cations causing hardness in water and the major anions associated

with them?

7. How is hardness classified?

8. Why is softening of water necessary? What are the advantages of soft water?

9. Among finished drinking water, raw wastewater and de-ionized water, which water is

expected to have the highest carbonate hardness and why?

10. A sample has 50mg/L Ca2+

,150mg/L Mg2+

, 50 mg/L Na+, 20 mg/L Cl

- and 100 mg/L

glucose. Calculate its total hardness, carbonate and non-carbonate hardness?

11. Define hardness with respect to water.

12. What are the constituents that cause hardness in water?

13. How do you classify the water based on hardness in water?

14. Which method is the best for hardness determination in water and why?

Marks Obtained:





DETERMINATION OF DISSOLVED OXYGEN (DO) Aim: To determine the quantity of dissolved oxygen present in the given sample(s) by using

Winkler’s (Azide modification) method.

Introduction:

Dissolved Oxygen (D.O.) levels in natural and wastewaters are dependent on the physical, chemical

and biochemical activities prevailing in the water body. The analysis of D.O. is a key test in water pollution

control activities and waste treatment process control.

The presence of oxygen is essential for the survival of aquatic life in water. This oxygen is especially

required by aerobic bacteria and other micro-organisms for degradation and stabilization of organic

constituents in waste water. A rapid fall in DO level in river water is one of the first indications of organic

pollution. Thus it is one of the important parameters for accessing the quality of water, water bodies and

plays a key role in water pollution control activities.

The major inputs of DO to natural water are from atmosphere and photosynthetic reaction. The

solubility to oxygen in water depends on pressure, temperature, altitude and chloride concentration etc.

The solubility of atmosphere oxygen in fresh water varies from 14.6 mg/lt at 0o C to about 7 mg/lt at

35o C under 1 atmospheric pressure. Low DO in water can kill fish and many other organisms in water. For

example, fish requires 2 mg/lt to 5 mg/lt of DO in water.

Principle:

Improved by various techniques and equipment and aided by instrumentation, the Winkler

(iodometric) test remains the most precise and reliable titrimetric procedure for D.O. analysis. The test is

based on the addition of divalent manganese solution, followed by strong alkali to the water sample in a

glass-stoppered bottle. D.O. present in the sample rapidly oxidises in equivalent amount of the dispersed

divalent manganous hydroxide precipitate to hydroxides of higher valency states. In the presence of iodide

ions and upon acidification, the oxidised manganese reverts to the divalent state, with the liberation of

iodine equivalent to the original D.O. content in the sample. The iodine is then titrated with a standard

solution of thiosulphate.

Apparatus:

1. BOD Bottle- 300 ml Capacity; 2. Conical Flask; 3. Burette; 4. Measuring Jars Reagents:

1. Manganous Sulphate



2. Alkali Iodide-Azide Solution

3. Starch Indictor

4. Standard Sodium Thio Sulphate (0.025 N)

5. Concentrated Sulphuric Acid

Procedure (Winkler Method):

1. Take the BOD bottle and fill it completely with the given sample of water.

2. Add 2 ml of Manganous sulphate and 2 ml of Alkali - Iodide – Azide solution to the BOD bottle. (The

tip of the pipette should be below the liquid level while adding these agents).

3. Stopper with care to exclude air bubbles and mix by repeatedly inverting the bottle 15 times.

4. After shaking and allowing sufficient time for all oxygen to react, the chemical precipitates are

allowed to settle leaving at least 100 ml of clear solution.

5. Add 2 ml of concentrate Sulphuric acid by allowing the acid to run down the neck of the bottle.

6. Restopper and mix by gentle invertion until the suspension is completely dissolved and yellow

colour is uniform throughout the bottle.

7. Measure out 203 mL of the solution from the bottle to an Erlenmeyer flask. As 2 mL each of

manganese sulphate and azide reagent have been added, the proportionate quantity of yellow

solution corresponds to 200 mL of sample is = (200×300/(300-4) =203mL

8. Titrate it against Sodium thio sulphate solution until dark yellow changes to pale yellow.

9. Add 1–2 mL starch solution and continue the titration to the first disappearance of the blue colour

and note down the volume of sodium thiosulphate solution added (V), which gives directly the D.O.

in mg/L.

Observations: Burette: 0.025N Na2S2O3

Conical flask: 203ml prepared sample (water + 2ml MnSO4 + 2ml alkali iodide azide + 2ml concentrated

H2SO4) titrated against burette solution until dark yellow changes to pale yellow. Indicator: Starch

(solution is turned to blue colour); End point: Blue to Colourless

SN Description of

sample(volume)

Initial Burette

reading

Final Burette

Reading

Volume of titrant

rundown (mL)



Results:

The Dissolved Oxygen present in the sample = …………….. mg/L

Discussion:


The oxygen remains in water in dissolved form depending upon the temperature of water. As the

temperature increases, the solubility of D.O in water decreases. For example the maximum D.O at 20oC

is 9.17 mg/l where as at 25oC it is 8.38 mg/l. A minimum of 4 mg/L D.O is essential for the aquatic life.

The organic matter present in the waste water poses a Biochemical Oxygen Demand. This demand is met

with the Dissolved Oxygen present in the fresh body of water. If the organic load (volume x BOD ) of the

waste water is more than the asset (volume x D.O ) the whole of the oxygen is depleted. This causes the

death of fish and other aquatic animals and plants and they being organic matter further increase the

demand of oxygen for the degradation. So it is necessary to find out the D.O of water to maintain sanitary

conditions. It can be achieved by the treatment of waste water. Treatment means the reduction of BOD

below the allowable limits. The limit is 30 mg/l for disposal of wastewater (sewage) in water.

Aerobic bacteria thrive when free oxygen is available in plenty. Aerobic conditions prevail when

sufficient DO is available in water. End products of aerobic metabolism are stable and not foul smelling.

Higher temperature, biological impurities, ammonia, nitrites, ferrous iron, chemicals such as hydrogen

sulphide and organic matter reduces DO values.

Algae group in water may release oxygen during its photosynthesis and DO may even shoot up to 300

mg/lt.

Drinking water should be rich in DO for good taste. However higher value of DO in water may cause

corrosion of iron and steel.

DO test is necessary for all aerobic biological waste treatment process to control rate of aeration.

DO test is used to evaluate the pollution strength of industrial and domestic waste.

Questions:

1. The concentration of Dissolved Oxygen in water is mainly dependent on

1. The temperature

2. Chloride concentration



3. Organic purity of water

4. All of the above

2. The minimum Dissolved Oxygen required for aquatic life in general is

a. 9.2 ppm (c) 4 ppm

b. 8.4 ppm (d) 12 ppm

3. The treatment of wastewater is mainly done

a) To satisfy its B.O.D.

b) To remove suspended solids

c) To remove odour

d) To remove colour

4. The allowable limit of BOD of wastewater to be disposed in rivers is

(i) 45 ppm (ii) 30 ppm

(ii) 100 ppm (iv) 300 ppm

5. The Dissolved Oxygen in potable water

(i) imparts freshness (ii) improves taste

(ii) improves smell (iv) none of the above

6. Discuss the environmental significance of dissolved oxygen.

7. Most of the critical conditions related to dissolved oxygen deficiency occur during summer months.

Why?

8. Why do we use 0.025 N sodium thiosulphate solution for the titration?

9. The turbulence of water should be encouraged. Why?

10. Draw the oxygen saturation curve.

Marks Obtained:





DETERMINATION OF BIOCHEMICAL OXYGEN DEMAND (BOD)

OF WASTE WATER

Aim: To determine the amount of BOD (Biochemical Oxygen Demand) exerted by a given sample of waste

water.

Introduction:

The Biochemical Oxygen Demand (B.O.D.) of sewage or of polluted water is the amount of oxygen

required for the biological decomposition of dissolved organic matter to occur under aerobic condition and

at the standardised time and temperature. Usually, the time is taken as 5 days and the temperature 20°C as

per the global standard. The B.O.D. test is among the most important method in sanitary analysis to

determine the polluting power, or strength of sewage, industrial wastes or polluted water. It serves as a

measure of the amount of clean diluting water required for the successful disposal of sewage by dilution.

The test has its widest application in measuring waste loading to treatment plants and in evaluating the

efficiency of such treatment systems.

Principle:

The test consists in taking the given sample in suitable concentrations in dilute water in B.O.D. bottles.

Two bottles are taken for each concentration and three concentrations are used for each sample. One set of

bottles is incubated in a B.O.D. incubator for 5 days at 20°C; the dissolved oxygen (initial) content (D1) in the

other set of bottles will be determined immediately. At the end of 5 days, the dissolved oxygen content (D2) in

the incubated set of bottles is determined.

Then, mg/L B.O.D. =

where, P = decimal fraction of sample used.

D1 = dissolved oxygen of diluted sample (mg/L), immediately after preparation.

D2 = dissolved oxygen of diluted sample (mg/L), at the end of 5 days incubation.

Among the three values of B.O.D. obtained for a sample select that dilution showing the residual dissolved

oxygen of at least 1 mg/L and a depletion of at least 2 mg/L. If two or more dilutions are showing the same

condition then select the B.O.D. value obtained by that dilution in which the maximum dissolved oxygen

depletion is obtained.

Apparatus: 1. BOD bottles; 2. Pipette; 3. Burette; 4. Conical Flask; 5. BOD Incubator; 6.Measuring Jar



Reagents:

1. 0.025N Sodium Thio - Sulpahte

2. Manganous Sulphate

3. Alkali- Iodide- Azide Solution

4. Concentrated Sulphuric Acid

5. Starch Indicator

6. Phosphate Buffer Solution

7. Magnesium Sulphate Solution

8. Ferric Chloride Solution

9. Calcium Chloride Solution

Procedure:

1. Preparation of aerated distilled water: Place desired volume of distilled water in a 5 litre flask. Aeration

is done by bubbling compressed air through water.

2. Add 1 ml each of phosphate buffer, magnesium sulphate solution, calcium chloride solution and ferric

chloride solution for every litre of distilled water.

3. In the case of waste water which is not expected to have sufficient bacterial population, add seed to the

diluted water. Generally 2 ml of settled domestic sewage is sufficient for 1000 ml of dilution water.

4. Highly acidic or alkaline sample are to be neutralized to a pH of 7.

5. Take the sample and dilute it with distilled water and mix contents well.

6. Take diluted sample into 2 BOD bottles.

7. Fill the other two BOD bottles with dilution water alone.

8. Find DO of diluted waste water and dilution water and note them down.

9. Incubate the other two BOD bottles in a BOD Incubator for 5 days at 200C. They are to be tightly

stoppered to prevent any air entry into the bottles.

10. Determine DO content in the incubated bottles at the end of 5 days.

11. Calculate the B.O.D. of the given sample.

Note: The procedure for determining the dissolved oxygen content is same as described in the experiment

under “Determination of dissolved oxygen”.



Observations:

Calculations:

Where:

DO = DO of diluted wastewater sample on 0th

day

D5 = DO of diluted waste water sample on 5th

day

BO = DO of blank solution before incubation

B5 = DO of blank solution after incubation of 5 days

Results:

The BOD of sample is ________________mg/L

Discussion:


The most widely used test indicating organic pollution of both wastewater and surface water is the

5-day BOD (BOD5). This determination involves the measurement of the dissolved oxygen used by

microorganisms in the biochemical oxidation of organic matter. BOD5 is the total amount of

oxygen consumed by microorganisms during the first five days of biodegradation. Oxygen demand

is associated with the biodegradation of the carbonaceous portion of wastes and oxidation of

Sample

DO of 0th

day DO of 5th

day

IBR FBR VR (DO)0 IBR FBR VR (DO)5

Sewage sample

Blank solution



nitrogen compounds such as ammonia. The following equations simplify the process of

biodegradation:

o Organic matter + O2 + microorganisms CO2 + H2O + new microbial cells

o Ammonia + O2 + microorganisms NO3 + H2O + new microbial cells

The determination of BOD is used in studies to measure the self purification capacity of streams and

help the regulatory authorities to check the quality of effluents discharged into such waters.

It is useful in determination of strength of domestic and industrial sewage.

BOD of wastewater is helpful in the design of treatment facilities and to evaluate the efficiency of

various treatment units.

It is a factor considered in choice of treatment method and is used to determine the size of certain units,

particularly trickling filters and activated sludge units.

It is the only parameter which gives an idea of the biodegradability of any sample and self purification

capacity of rivers and streams.

Drinking water usually has a BOD of less than 1 mg/L and water is considered fairly well up to 3 mg/L

of BOD. But when BOD value reaches 5 mg/L, the purity of water is doubtful.

Any effluent to be discharged into natural bodies of water should have BOD less than 30 mg/L as per

CPCB Guidelines.

Questions:

1. What use is made of the B.O.D. test in water pollution control?

2. What are the three methods that can be used to control nitrification in the 5 days B.O.D. test at 20°C?

3. What are the factors affecting the rate of biochemical oxidation in the B.O.D. test?

4. What purpose or purposes are served by each of the following in BOD dilution

water: (a) FeCl3, (b) MgSO4, (c) K2HP04, (d) NH4C1 and (e) CaCl2

5. What justification does the engineer have for using first-order reaction kinetics to describe the complex

biochemical processes occurring in the BOD test?

6. What is carbonaceous and nitrogenous BOD?

7. Draw and explain the BOD curve.

Marks Obtained:





DETERMINATION OF CHLORIDE CONTENT IN THE GIVEN SAMPLE Aim: To determine the chloride content in the given sample

Introduction:

Chloride occurs in all natural waters in widely varying concentrations. Chloride in the form of

chlorine ions is one of the major inorganic anions in water and waste water; in potable water the salty

taste produced by chloride concentration is variable and dependent on the chemical composition of water.

Some water containing 250mg/l may have a detectable salty taste if the cation is sodium. On the other

hand the typical salty taste may be absent in water containing as much as 100mg/l, when the predominant

cations are calcium and magnesium. Principle:

In neutral or slightly alkaline water potassium chromate can indicate the end point of the silver

nitrate. Silver chloride precipitated quantitatively before red silver chromate precipitate is formed.

Apparatus:

1. Burette; 2. Pipette; 3. Conical flask Reagents:

1. Chloride free distilled water

2. Potassium chromate indicator.

3. Standard silver nitrate (0.0141N)

4. Standard sodium chloride (0.0141N)

Procedure:

1. Take 25ml of sample in conical flask.

2. Adjust its pH between 7.0 and 8.0 either with sulphuric acid or sodium hydroxide solution.

Otherwise AgOH is formed at high pH level.

3. Add 1ml of potassium chromate to get light yellow colour.

4. Titrate with standard silver nitrate solution till colour change from yellow to brick red.

5. Note down the volume of silver nitrate added (A).

6. If more quantity of potassium chromate is added, silver chromate may form too soon or not soon

enough.

7. For better accuracy, titrate distilled water in the same manner.

8. Note the volume of silver nitrate added for distilled water (B).



Observation: Burette: 0.0141N silver nitrate solution

Conical flask: 25ml of sample

Indicator: Potassium chromate

End Point: Yellow to Brick red

Volume of Observations Chloride

Sample sample taken Initial burette Final burette AgNO3 solution content (ml) reading (IBR) reading (FBR) consumed (VR mg/L

= FBR – IBR)

Water

A =

Blank solution

B = Calculations:

Result:

Chloride content of the given sample is = ………………………… mg/lt

Discussion:



Environmental significance:

Chlorides determination in natural waters is useful in the selection of water supplies for human use.

Chlorides determination is used to determine the type of desalting apparatus to be used.

The chloride determination is used to control pumping of ground water from locations where intrusion

of sea water is a problem.

Questions:

1. What is the need to adjust the pH of the sample to 7-8 in chlorides estimation?

2. What is the effect of temperature in the determination of chlorides?

3. What is meant by indicator blank correction?

4. What process is to be used to remove excess chlorides in water?

Marks Obtained:




EXPERIMENT NO 08 DATE: _________

DETERMINATION OF PERCENTAGE OF AVAILABLE CHLORINE

IN BLEACHING POWDER

Aim: To determine chlorine content in the given bleaching powder sample Introduction: Chlorine is a strong oxidizing agent and a very effective disinfectant used for the

destruction of pathogenic bacteria. Chlorine is generally applied in the form of bleaching powder for

disinfection of water. Commercial bleaching powder generally contains 25 to 30% of available

chlorine. This percentage is very critical for effective disinfection of water.

Principle:

The chlorine present in the bleaching powder gets reduced with time. So, to find the exact quantity of

bleaching powder required, the amount of available chlorine in the sample must be found out. Chlorine

will liberate free iodine from potassium iodide solution when its pH is 8 or less. The iodine liberated,

which is equivalent to the amount of active chlorine, is titrated with standard sodium thiosulphate

solution using starch as indicator. Apparatus:

1. Burette; 2. Pipette;3. Conical flask; 4. Beaker; 5. Funnel

Reagents: 1. Standard sodium thiosulphate solution (0.025N)

2. Potassium iodide

3. Starch indicator

4. Iodine solution (0.025 N).

5. Glacial Acetic Acid

Procedure:

1. Weigh 1g of bleaching powder and make it into a paste by adding small quantity of distilled

water. Add some water stir it and allow it to settle for a few minutes. Decant the supernatant

solution and dilute to 1000ml with distilled water in a volumetric flask and stopper it. This is

called chlorine water/ standard chlorine solution.

2. Place 5 mL glacial acetic acid in an Erlenmeyer flask and add about 1g potassium iodide

crystals. Pour 25 mL of bleaching powder solution prepared above and mix with a stirring rod.

Wait for 15 to 20 minutes.



3. Titrate with 0.025N Sodium Thio-Sulphate solution until a pale yellow colour is obtained. (Deep

yellow changes to pale yellow.)

4. Add 1 mL of starch solution. The solution becomes blue in colour.

5. Continue the titration till the blue colour disappears. Note down the volume of sodium Thio-

Sulphate run down(V1).

6. Take a volume of distilled water corresponding to the sample used.

7. Add 5 mL acetic acid, 1g potassium iodide and 1 mL starch solution.

8. If blue colour occurs, titrate with 0.025 N sodium thiosulphate solution until the blue colour

disappears.

9. Record the volume of sodium thiosulphate solution added (A1).

10. If no blue colour occurs, titrate with 0.025 N iodine solution until a blue colour appears. Note

down the volume of iodine (A2).

11. Then, titrate with 0.025 N sodium thiosulphate solution till the blue colour disappears. Record

the volume of sodium thiosulphate solution added (A3). Note down the difference between the

volume of iodine solution and sodium thiosulphate as A4(A4=A2 – A3).

Note: Blank titration is necessary to take care of the oxidising or reducing reagents’ impurities.

Observations:

1. Burette: 0.025N Sodium Thiosulphate solution

2. Conical Flask: 100ml bleaching powder solution + 5ml Glacial Acetic acid + pinch of potassium

iodide.

3. Indicator: Starch

4. End point: Blue to colourless

1. Bleaching powder solution:

Trial No. Sample Initial Burette

Reading (IBR)

Final Burette

Reading (FBR)

Volume

Rundown

VR =FBR - IBR



2. Distilled water

Trial No. Sample Initial Burette

Reading (IBR)

Final Burette

Reading (FBR)

Volume

Rundown

V =FBR - IBR

Calculations:

1000 mL of bleaching powder solution contains 1000 × ____________ mg of Chlorine

i.e., 1000 mg bleaching powder contains …………………………… mg of Chlorine.

Percentage of chlorine available in bleaching powder = ____________

Results:

The available chlorine content in the given bleaching powder sample is = ………….mg /L

Percentage of chlorine available in bleaching powder = ____________

Discussion:


1. This test is useful to assess the quality of bleaching powder.

2. It is useful to estimate the bleaching powder required for effective disinfection of water.



Questions:

1. What is disinfection? Differentiate between disinfection and sterilisation?

2. Why do we prefer chlorination over other methods of disinfection?

3. Discuss the effect of pH of water and organic matter of water on efficiency of disinfection by

chlorine.

4. What is electro-katadyn process?

5. By use of appropriate equilibrium equations show why the addition of chlorine tends to decrease the

pH of water, while hypochlorite tends to increase the pH.

Marks Obtained:

Signature of Course Co-ordinator:




TO DETERMINE THE RESIDUAL CHLORINE Aim: To determine the residual chlorine in a given sample of water

Introduction:

The process of killing infectious bacteria in water and making it safe to users is called disinfection. The

most commonly used disinfectant chlorine may be applied in gaseous form or in the form of bleaching

powder (CaOCl2).

Chlorination may produce adverse effects. Taste and odour characteristics of phenols and other organic

compounds present in a water supply may be intensified. Potentially carcinogenic chloro-organic compounds

such as chloroform may be formed. Combined chlorine formed on chlorination of ammonia-or amine-bearing

waters adversely affects some aquatic life. To fulfill the primary purpose of chlorination and to minimize any

adverse effects, it is essential that proper testing procedures be used.

Chlorine applied to water in its molecular or hypochloric form initially undergoes hydrolysis to form

free chlorine consisting of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion. The relative

proportion of these free chlorine forms is pH and temperature-dependent. At the pH of most waters,

hypochlorous acid and hypochlorite ion will predominate.

Free chlorine reacts readily with ammonia and certain nitrogenous compounds to form combined

chlorine. With ammonia, chlorine reacts to form the chloramine, dichloramine and nitrogen trichloride. The

presence and concentration of these combined forms depend chiefly on pH, temperature, initial chlorine-to-

nitrogen ration, absolute chlorine demand and reaction time. Both free formed in the treatment of raw waters

containing ammonia or by the addition of ammonia or ammonium salts. Chlorinated wastewater effluents as

well as certain chlorinated industrial effluents, normally contain only combined chlorine. Historically the

principal analytical problem has been to distinguish between free and combined forms of chlorine.

Chlorine and its derivatives inactivate the enzymatic system of pathogenic bacteria present in water.

For efficient chlorination water should be intermixed thoroughly with chlorine and let to stay with reagent for

at least 30 minutes before delivering to consumer.

Residual chlorine is the chlorine remaining in water after contact period (of 30 to 60 min). During

chlorination process, sufficient quantity of chlorine must be added to reach 0.01 to 0.02 mg/L of residual

content of non-reacted chlorine in treated water.

Principle:

Chlorine present in water reacts with potassium iodide and iodine is liberated. When starch is used as

indicator, the presence of blue colour indicates the presence of iodine.

Apparatus:

1. Burette; 2. Pipette; 3. Conical flask; 4. Beaker



Reagents:

1. 0.025N Sodium Thio-sulphate

2. Glacial acetic acid

3. Potassium iodide solution

4. Starch solution indicator

Procedure:

1. Take 6 beakers with increasing dosage of standard chlorine solution. Add 100ml of Tap water to each

beaker and mix well.

2. To this add 5ml of glacial acetic acid and pinch of potassium iodide and place it aside for 10 minutes.

3. Titrate the solution from each beaker against 0.025 N Sodium Thio-sulphate to pale yellow colour, by

adding add 1 ml of starch solution until the solution turns from blue to colourless.

4. Note down the burette reading and calculate the amount of residual chlorine present.

Observation:

Beaker Dosage of Available Available Initial Final Volume Residual Chlorine

No Bleaching chlorine chlorine Burette Burette Rundown; Free demand =

Powder (mg/ml) (AC) Readin Reading VR = chlorine AC –

solution (mg/lt) g (IBR) (FBR) FBR - (RFC) RFC

(ml) IBR mg/lt (mg/lt)

1 5

2 10

3 15

4 20

5 25

6 30



Calculations:

Where,

VR= Volume of Sodium thio-sulphate Run-down N = Normality of sodium thio-sulphate.

Enclose Graph Sheet

Results:

The residual chlorine present in the sample = ……………………… mg/lt Discussion:



Environmental Significance: 1. The chlorination of water supplies and polluted waters serves primarily to destroy or

deactivate disease-producing micro-organisms. A secondary benefit, particularly in treating

drinking water, is the overall improvement in water quality resulting from the reaction of chlorine

with ammonia, iron, manganese, Sulphide and some organic substances.

2. Determination of residual chlorine is used to control chlorination of domestic and industrial

waste water.

3. Determination of chlorine residual is used universally in disinfection practice to control the

chlorine so as to ensure effective disinfection without waste.

4. Determination of chlorine residual in water distribution is useful to find the source of

contamination or leakage point so as to supply wholesome water to consumer.

5. Residual chlorine should be present in drinking water within range of 0.1 to 0.2 mg/ltr.

However excess chlorine content may give out bad odour and may change even taste of water.

6. Excess chlorine is said to be carcinogenic.

7. Residual chlorine should be present in the drinking water within range of 0.1 to 0.2mg/ltr.

However excess chlorine content may give out bad odour and may changes even taste of water.

8. Excess chlorine is said to be carcinogenic.

Questions:

1. What is chlorination?

2. Explain the reactions occurring during chlorination while disinfection of water.

Marks Obtained:





DETERMINATION OF SOLIDS

Aim: To determine the total solids, fixed solids, volatile solids, settleable solids, suspended solids,

and dissolved in a given sample. Introduction:

Normally the sewage water sample contains 99.9 % water and 0.1% solids. The term solids in

water and waste water for a sanitary engineer refers to as the matter which remains as a residue after

evaporation and subsequent drying at specified temperature of 100 to 105o C. the total solids is

considered as the sum of dissolved solids and suspended solids.

1) Total Solids: They indicate both organic and inorganic matter. Organic solids are also called

as volatile solids and inorganic solids are also called non-volatile solids.

2) Suspended Solids: These are of two types: settleable and non-settleable solids. Settleable

solids are those which will settle down in the sedimentation tank with a usual detention

period of 1 to 3 hours. Non-settleable solids will not settle down and are usually volatile in

nature.

3) Dissolved Solids: They are present in dissolved state and can be determined indirectly.

4) Fixed Solids: The residue obtained in total solids test is heated to 550 ± 50o C in a muffle

furnace at a constant rate for about 1 hour. The volatile solid vaporizes and the residue that

remains is the fixes solids.

I. Total, Fixed And Volatile Solid:

Apparatus:

6. Evaporating Dish (Gooch Crucible); 2. Oven (103o C); 3. Muffle Furnace (550 ± 50

o C);

4. Weighing Balance

A. Procedure (Total Solids)

1. Take a clean crucible and make it completely dry in oven, cool it and take its initial weight as

W1

2. Add 25 ml of well mixed sample to crucible.

3. The sample is evaporated by heating at 100 to 103o C for 1 hour.



4. The residue left in the dish is weighed after cooling as W including weight of the dish.

B. Procedure [Fixed and volatile Solids]:

1. The crucible which contains total solids will be used in this experiment.

2. Place the crucible in a muffle furnace at 550 ± 50o C for 15 to 20 minutes.(At 550 ± 50

o C

all the volatile matter will burn out leaving behind only fixed solids or inorganic solids)

3. Allow the dish to cool and note down the weight as W3.

4. The residue remaining in the crucible is the fixed solids.

II. Suspended and Dissolved Solids:

Apparatus:

1.Vaporating Dish; 2. Oven (103o C); 3. Filter Paper; 4. Weighing Balance.

Procedure: [Suspended Solids]

1. Measure the initial weight of clean filter paper (F1).

2. 100 ml of sample is taken and passed through filter paper by placing on the funnel.

3. The filter paper is removed and dried in oven at 103o C.

4. It is cooled and final weight in notes as (F2).

Procedure : [Dissolved Solids]

1. Determine the initial weight of the evaporating dish (D1) 2. Collect about 50 ml of filtrate from the above sample and pour it into the dish.

3. Place the dish along with the filtrate in an oven at 100 to 103

o C and evaporate the filtrate

sample. (Under any circumstance the sample should not be boiled).



4. When the sample is completely evaporated from the dish, take out from the oven, take out

from the oven, cool to lab temperature and note down the weight of the dish as (D2).

III. Settleable Solids:

Apparatus:

1. Imhoff Cone; 2. Stirring Rod; 3. Measuring Jar

Procedure:

1. Mix thoroughly the given waste water sample

2. Place the Imhoff Cone on the stand

3. Pour the thoroughly mixed sample into the imhoff cone upto 1 Ltr Mark.

4. Gently Stir the sides of the cone with a rod or by spinning.

5. Allow the sample to settle at least for 45 to 60 minutes.

6. At the end of 45 minutes note down the settleable solids in cone in ml/ltr.



Observations:

Total Solids

W1 = Empty Weight of gooch crucible = …………………………mg

W2 = Weight of gooch crucible + water sample (after Oven dry 103- 105o C) =

………………… mg

=

= ………………………….. mg/lt

Fixed Solids

W3 = weight of gooch crucible + Sample @ W3 (after 20mins in Muffle furnace @ 550o C)

= ………………………………… mg

=

= ……………………………… mg/lt

Volatile Solids = Total Solids – Fixed Solids

=

= …………………………. mg/lt



Suspended Solids

Weight of filter paper, W1 (Mg) = ………………….

Weight of filter paper + Solids W2 = ………………..

Therefore: Weight of solids, W3 = W2 – W1 = …………………….

=

= ………………………………..mg/lt

Dissolved Solids

Weight of gooch crucible, W4 (Mg) = ……………………

Weight of gooch crucible + Oven dried Filtrate = W5 (103 – 105o C) = ………………………

Therefore:

=

=……………………………mg/lt Settleable solids of waste water sample = ………………………. mg/lt



Results: Total solids of waste water sample = ………………………….. mg/lt

Fixed solids of waste water sample = …………………………… mg/lt

Volatile solids of waste water sample = ………………………… mg/lt

Dissolved solids of water sample = ………………………………. mg/lt

Suspended solids of water sample = ……………………………… mg/lt

Settleable solids of waste water sample = ………………………. mg/lt

Discussion:


1. The suspended solids parameter is used to measure the quality of waste water influent and

effluent and also extremely valuable in analysis of polluter water.

2. It is used to evaluate strength of the domestic waste water.

3. Dissolved substances are undesirable in water. Dissolved Minerals, gasses and organic

constituents may produce aesthetically displeasing color, taste and odor.

4. Some dissolved organic chemicals may deplete the dissolved oxygen in receiving water and

some may also be carcinogenic.

5. Water with higher solid continent often has a Laxative effect and sometimes the reverse

effect on people whose bodies are not adjusted to them.

6. High concentration of dissolved solid of about 3000 mg/lt may also produce distress and

livestock. In industries the use of water with high amount of dissolved solids may lead to

scaling in boilers, corrosion and degraded quality of product.

7. Water consisting of high volatile solids is not suitable for drinking purpose. It indicates that

the water may have been polluted by domestic wastes and other organic waste. In general

groundwater is free from volatile Solids. Surface water may have high volatile solids due to

disposal of domestic and other wastes.



8. The settleable solids determination is used extensively in analysis of industrial waste to

determine the need and design of plain settling tanks in plans employing biological

treatment process.

9. It is also used in waste water treatment plants to determine efficiency of sedimentation tank.

10. Biologically active suspended solids may include disease causing organisms as well as

organisms such as toxin producing algae.

Questions:

1. Define a solid with reference to environmental engineering.

2. What is the significance of determining settleable solids in water and waste water by imhoff

cone?

3. What is the normal size of colloids in water?

4. What methods are available for the removal of organic dissolved solids in water and waste

water?

Marks Obtained:





DETERMINATION OF TURBIDITY OF A GIVEN SAMPLE

Aim: To find out the turbidity of a given sample of water.

Introduction:

Insoluble particles of soil, inorganic and organic materials and other micro-organisms

impede (obstruct) passage of light by scattering and absorbing the light rays. The interference to

passage of light is turbidity. It is usually caused by the finely dissolved and sometimes suspended

particles of clay loam sand and microscopic organisms all in suspension. Turbidity is measured photometrically by determining the quantity of light of given intensity

absorbed / scattered. Jackson turbidity meter and Nephlo turbidity meter in generally used to measure turbidity of water

samples. Jacksons turbidity meter in generally is based on light absorption and nephlo turbidity

meter is based on intensity of light scattered by the sample, taking a reference with standard

turbidity meter suspensions. Nephlometric turbidity meter is generally used for samples with low turbidity and expressed as

NTU or mg/ltr. For portable water allowable turbidity is between 5 to 10 mg/ltr. Apparatus:

1. Nephlo turbidity meter; 2. Sample Tubes

Procedure:

1. Switch on the instrument and allow sufficient warm-up period.

2. Take distilled water or bank solution in the test tube holder and close the lid. Make sure that

the mark on the test tube coincides with mark on the panel.

3. Select required range for measurement.

4. Adjust the displayed to ‘000’ by adjusting set zero knob.

5. Remove the test tube containing distilled water and insert another test tube containing standard

solution (say 100 NTU or 400 NTU). Place it in test tube holder.

6. Adjust the calibrate knob so that the display reach the standard solution value.

7. Again check ‘0’ display with distilled water. The instrument is now calibrated.



8. Place the given sample whose turbidity is to be determined in the test tube and take the reading

in NTU.

Observations:

SN Sample Details Turbidity Remarks

(NTU)

Results:

The turbidity of the given sample is = ……………… NTU

Discussion:


1. Turbidity is objectionable because of aesthetic and engineering considerations.

2. Disinfection of turbid water is difficult because of adsorptive characteristics of

some colloids and their tendency to solid organisms from the disinfectant.

3. In natural water bodies, turbidity interferes with light penetrations and

pathogenic reactions of aquatic plants.

4. Turbidity measurements are useful to determine whether a supply requires

special treatment by chemical coagulation before public water supply. It is also

used to determine the effectiveness of treatment produced with different

chemicals and dosage needful.

5. Measurement of turbidity in settled water prior to filtration is useful in

controlling the chemical dosage so as to excessive loading of rapid sand filters.

6. It is also useful to determine the optimum dosage of coagulants and to evaluate

the performance of water treatment plants.



Questions:

1. What are the causes of turbidity in water?

2. What units are used for measuring turbidity?

3. What is the difference between visual method and instrumental method in turbidity

measurement?

4. What is meant by coefficient of fineness? Mention its importance.

5. What is the basic difference in principle involved in Jackson turbid meter and

Nephelo turbidity meter?

6. What is the general coagulant used for removal of turbidity in water?

Marks Obtained:





DETERMINATION OF OPTIMUM DOSAGE OF COAGULANT Aim: To determine the optimum dosage of coagulant

Introduction:

The solids may vary in size from 1 milli micron to 200 milli micron and broad in

characteristics between suspended and dissolved solids. They are small enough to exhibit stability

by virtue of slight residual electrical charge but large enough to interfere with passage of light and

therefore cause turbidity. They will not settle physically unless destabilized, coagulated and

flocculated into larger mass with sufficient greater densities than water. Principle:

Metal salts hydrolyse in presence of the natural alkalinity to form metal hydroxides. The

divalent cation can reduce the Zeta potential while the metal hydroxides are good adsorbents and

hence remove the suspended materials. Alum [Al2(SO4)3. 18H2O] is the most widely used

coagulant. When alum solution is added to water, the molecules dissociate to yield sulphate and

aluminium ions. The +ve species combine with negatively charged colloidal to neutralise 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.

A flash mixer accomplishes this.

Jar test is simple device used to determine this optimum coagulant dose required. The jar

test, device consists of a number of stirrers (4 to 6) provided with paddles. The paddles can be

rotated with varying speed with the help of a motor and regulator. Samples will be taken in jars or

beakers and varying dose of coagulant will be added simultaneously to all the jars. The paddles

will be rotated at 100 rpm for 1 minute and at 40 rpm for 20 to 30 minutes, corresponding to the

flash mixing and slow mixing in the flocculator of the treatment plant. After 30minutes settling,

supernatant will be taken carefully from all the jars to measure turbidity. The dose, which gives the

least turbidity, is taken as the optimum coagulant dose.

Apparatus:

1. pH meter; 2. Turbidity meter; 3. Flash mixer; 4. Jar test apparatus; 5. Titration apparatus.

Reagents:

1. Alum Solution

2. H2SO4



3. Phenolphthalein indicator

4. Methyl orange

Procedure:

1. Take 6 beakers containing 1 ltr of sample

2. Check the initial pH, turbidity, alkalinity of the given sample. If pH is low add soda ash or

lime make up the pH between 6.5 - 8.5.

3. Add the coagulant alum for the beakers in increasing order.

4. With the help of flash mixer go for the process of coagulation with the speed between 80-

100 rpm for 15 minutes.

5. After 15 minutes, slow down the speed between 20-30 rpm and stir for 5-10 minutes.

6. After all the above process keep the beaker for a detention period of 20-30 min for efficient

settling of flocks.

7. Take out the supernatant liquid without disturbing the sediment and check the final

turbidity and alkalinity of all the beakers.

Observations and Calculations:

Raw water sample:

Initial pH = ......................

Initial alkalinity = ..................mg/L

Initial turbidity = ...................NTU

Beaker Dosage of pH Turbidity Alkalinity = VR * 1000/ ml of sample % removal of

No Coagulant (NTU) turbidity.

(ml)

IBR FBR VR Alkalinity

(mg/lt)

1 2

2 4

3 6

4 8

5 10

6 12



From the graph; we can conclude that whichever will give maximum turbidity removal, that

dosage of alum will be the optimum dosage of coagulant.

Enclosure Graph sheet Results:

Optimum dosage of coagulant to be added for the given water sample is …………. ml

Discussion:


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.

To maintain the cost of operation and maintenance, optimum dosage quantity is essential

to be determined.



Questions:

1. List out the advantages and disadvantages of Alum as a coagulant.

2. Enumerate various coagulants which can be used in water treatment.

3. Write down the equation of coagulation using alum.

Marks Obtained:





DETERMINATION OF SODIUM CONTENT Aim: To determine the sodium content in the given sample by flame photometer.

Introduction:

Trace amounts of sodium can be determined in either direct reading or an internal standard

type flame photometer at a wave length of 589 nm. The sample is sprayed into a gas flame and

excitation is carried out under carefully controlled and reproducible conditions. The desired spectral

line is isolated by the use of interference filters. The intensity of light is measures by a photo tube

potentio meter. The intensity of light 589 nm is approximately proportional to the concentration of

the element. Apparatus:

1. Flame photometer

Reagents:

1. Deionised distilled water

2. Stock sodium solution

3. Intermediate solution

4. Standard sodium solution

5. Standard lithium solution. Procedure:

1. Prepare a blank and sodium calibration standards in stepped amounts in any of the following

applicable ranges 0 to 1.0, 0 to 10 or 0 to 100 mg/L.

2. Starting with the highest calibration standard and working towards the most dilute, measure

emission at 589 nm.

3. Repeat the operation with both calibration standards and samples enough limes to secure a

reliable average reading for each solution.

4. Construct a calibration curve from the sodium standards.

5. Determine sodium concentration of sample from calibration curve.



Procedure: For Bracketing Approach:

1. From the calibration curve, select and prepare sodium standards that immediately bracket the

emission intensity of the sample.

2. Determine emission intensities of the bracketing standards (one sodium slightly less and other

slightly greater than the sample) and the sample as nearly simultaneously as possible.

3. Repeat the determination on bracketing standards and sample.

Calculations: For direct reference to the calibration curve:

Mg Na/l = (mg Na/l in portion) * D

For the bracketing approach:

Mg Na/l = [({(B-A)(s-a)}/(b-a))+A]D

Where:

B= mg Na/l in upper bracketing standard

A= mg Na/l in upper bracketing standard

b= emission intensity of upper bracketing standard

a= emission intensity of upper bracketing standard

s= emission intensity of sample

D= dilution ration=(ml sample + ml distilled water) / ml of sample

Results: The sodium content in the given sample:

Sample 1: …………………………

Sample 2: …………………………

Discussion:



Activity:

Write down how high or low concentrations of sodium can effect health of humans and effect the

environment.

Marks Obtained:





DETERMINATION OF POTASSIUM CONTENT

Aim: To determine the potassium content in a given sample by flame photometer.

Introduction:

Trace amounts of potassium can be determined in either direct reading or an internal

standard type flame photometer at a wave length of 766.5 nm. Because much of the information

pertaining to sodium applies equally to the potassium determination carefully study the entire

discussion dealing with flame photometer determination of sodium before making of potassium

determination. Apparatus:

1. Flame photometer

Reagents:

1. Deionised distilled water

2. Stock potassium solution

3. Intermediate potassium solution. Procedure:

1. Prepare a blank and potassium calibration standards in stepped amounts in any of the

following applicable ranges 0 to 1.0, 0 to 10 or 0 to 100 mg/ltr.

2. Starting with the highest calibration standard and working towards the most dilute, measure

emission at 766.5 nm.

3. Repeat the operation with both calibration standards and samples enough limes to secure a

reliable average reading for each solution.

4. Construct a calibration curve from the potassium standards.

5. Determine potassium concentration of sample from calibration curve.

Procedure:

For Bracketing Approach:

1. From the calibration curve, select and prepare potassium standards that immediately bracket

the emission intensity of the sample.



2. Determine emission intensities of the bracketing standards (one potassium slightly less and

other slightly greater than the sample) and the sample as nearly simultaneously as possible.

3. Repeat the determination on bracketing standards and sample.

Calculations: For direct reference to the calibration curve:

Mg K/l = (mg K/l in portion) * D

For the bracketing approach:

Mg K/l = [({(B-A)(s-a)}/(b-a))+A]D Where:

B= mg K/l in upper bracketing standard

A= mg K/l in upper bracketing standard

b= emission intensity of upper bracketing standard

a= emission intensity of upper bracketing standard

s= emission intensity of sample

D= dilution ration=(ml sample + ml distilled water) / ml of sample

Results:

The potassium content in the given sample:

Sample 1: …………………………

Sample 2: …………………………




DETERMINATION OF NITRATES Aim: To determine the nitrates by Spectrophotometer method.

Introduction:

Nitrate reacts with phenol disulphonic acid produces a nitro derivative, which is alkaline

medium develops a yellow color. The color produced follows the Beer’s law and is directly

proportional to the concentration of nitrate present in the sample. Apparatus:

1. Spectrophotometer; 2. Nessler’s tubes

Figure: Spectrophotometer Reagents:

1. Standard silver sulphate,

2. Phenol-di-sulphonic acid

3. Ammonium hydroxide,

4. Stock nitrate solution,

5. Standard nitrate solution. Procedure:

1. Take 50 ml of filtered sample in an Erlenmeyer flask.

2. Add an equivalent amount of silver sulphate to remove chlorides (1 mg/ltr = 1 ml Ag2SO4

solution) 3. Heat slightly and filter the precipitate of AgCl.

4. Evaporate the filtrate in a porcelain dish to dryness.



5. Cool and Dissolve the residue in 2 ml phenol di sulphonic acid and dilute to 50 ml. 6. Add 10 ml of liquid ammonia to develop the yellow color.

7. Read the color developed at 410 nm with a light path 1 cm.

8. Calculate the concentration of nitrate nitrogen from the standard curve.

9. Prepare the standard curve using suitable aliquots of standard nitrate solution in the range of 5 to

500 mg.

Results:

The nitrate content in the given sample is:

Sample 1: ………………………….

Sample 2:………………………….. Discussion: Environmental Significance:

1. Nitrate determinations are important whether the water supplies meet the BIS for the

control of the methemoglobinemia in infants.

2. It is used to access the self-purification properties of water bodies and nutrient balance in

surface waters and soil.

3. It is useful to find out state of decomposition of organic matter in waste water. Questions: 1. Explain the general principle and working of Spectrophotometer.

Marks Obtained:





DETERMINATION OF IRON

Aim: To determine the Iron content in the given sample by phenanthroline method. Introduction:

Iron is brought into solution reduced to the ferrous state by boiling with acid and

hydroxylamine and treated with 1-10 phenanthroline at pH 3.2-3.3 to form a complex orange red

colour. The intensity of colour is proportional to the concentration of iron and obeys Beer’s law.

Apparatus:

2. Nesslers tubes; 2. Conical flasks; 3. Pipettes; 4. Hot Plate

Procedure: 1. Take 50ml of given sample in a conical flask.

2. Add 1 ml of Hydroxyl amine hydrochloride solution and 2ml of Conce. HCl. Add few glass

beads and heat this sample until the volume of the solution reduces to 15 – 20 ml.

3. Cool the solution to room temperature and transfer this to a Nessler’s tube.

4. Add 2ml of phenanthroline solution and 10 ml of Ammonium acetate buffer.

5. Make up the contents of Nessler’s tube exactly to 100ml by adding distilled water and allow

at least 10-15 minutes for colour development.

6. Compare this solution with Iron standards and note down the reading with which standard it

matches.

7. The matching colour standard will give the concentration of iron in the sample.

Observations And Calculations:

Results:

The iron content in the given sample is = …………………..



Discussion: Environmental significance

1. Iron content of the water is important in determining the suitability of water for domestic and

industrial purposes.

2. Determination of iron is useful to select the treatment unit and design of treatment units

3. The ratio of iron to manganese is a characteristic factor that determines the type of treatment

unit used as well as the amount of organic matter present in the water.

4. It is also used to aid in the solution of problems in distribution systems where iron fixing

bacteria are troublesome.

5. The iron determination is helpful in assessing the extent of corrosion and aiding in control of

corrosion.

Questions:

1. Other than the above method, which method of analysis can be employed to determine the quantity

of Iron.

Marks Obtained:





DETERMINATION OF MANGANESE

Aim: To determine the manganese content in the given sample. Introduction:

Manganese is associated with iron minerals and occurs in nodules in ocean, fresh water and soils.

The common ores are pyrolusite and psilomelane. Manganese is used in steel alloys, batteries and

food additives. The FAO-recommended maximum level for manganese in standard is 50μg/L. BIS

desirable limit is 0.1 mg/L.

Principle:

Persulphate oxidation of soluble manganous compounds to form permanganate is carried out in the

presence of silver nitrate. The resulting colour is stable for at least 24h if excess Persulphate is

present and organic matter is absent.

Apparatus: 1. Colorimetric equipment 2. Conical flasks; 3. Pipettes; 4. Hot Plate

Reagents: Ammonium persulphate; Standard manganese solution

Procedure:

1. Pipette a portion containing 0.05 to 2mg Mn into a 250mL conical flask. Add distilled water, if

necessary, to 90mL and proceed.

2. To a suitable sample portion add 5mL special reagent and 1 drop H2O2. Concentrate to 90mL by

boiling or dilute to 90mL.

3. Add 1g (NH4)2S2O8, bring to a boil and boil for 1min.

4. Do not heat on a water bath. Remove from heat source, let stand 1 min and then cool under the tap

(boiling too long results in decomposition of excess Persulphate and subsequent loss of

permanganate colour; cooling too slowly has the same effect).

5. Dilute to 100mL with distilled water free from reducing substances and mix. Prepare standards

containing 0, 5, to 1500μg Mn by treating various amounts of standard Mn solution in the same way.

Photometric determination:

1. Use a series of standards from 0 to 1500μg Mn/100 ml. final volume.

2. Make photometric measurements against a distilled water blank.

The following table shows light path length appropriate for various amounts of manganese in 100ml.

final volume:



Mn Range(μg) Light Path(cm)

5-200 15

20-400 5

50-1000 2

100+1500 1

Prepare a calibration curve of manganese concentration vs. absorbance from the standards and

elements and determine Mn in the samples from the curve.

Calculation

i. When the entire original sample is taken for analysis:

Mn, mg/L = {μg Mn (in 100mL final volume) / mL sample} x {100 / mL portion}

ii. When a portion of the digested sample (100mL final volume) is taken for analysis:

Mn, mg/L = μg Mn / 100mL / mL sample

Results:

The manganese content in the given sample is = …………………..

Discussion:

Environmental significance In explorations of new water supplies, particularly from underground sources, iron and manganese

determinations are important considerations. Supplies may be rejected on this basis alone. When

supplies containing amounts in excess of 0.3 mg/L iron and 0.05 mg/L manganese are developed ,

the engineer must decide whether treatment is justified, and if so, which is the best method. The

efficiency of treatment units is determined by routine tests of iron and manganese.

Questions:

1. What is the environmental significance of iron and manganese in water supplies?

2. Discuss briefly how iron and manganese get into underground water supplies?

3. What analytical methods area generally used for measuring the concentration of manganese in

water supplies?

4. What is the principle of colorimetric determinations?

Marks Obtained:




EXPERIMENT NO 18 (DEMO) DATE: _________

DETERMINATION CHEMICAL OXYGEN DEMAND (COD) Aim: To determine chemical oxygen demand (COD) of a given waste water sample.

Introduction:

COD is the oxygen required for the oxidation (chemical) of organic matter by strong

chemical oxidant (K2Cr2O7) under acidic condition. In COD test the main disadvantage is that along

with the organic matter, some inorganic substance like Nitrates, Chlorides, Sulphides also get

oxidized (However some organic substances like Amino Acids, Benzene, Ketone, etc., do not get

oxidized). Hence, this test does not give the exact measure of the strength of organic wastes. The

main limitation of the test lies in its inability to differentiate between biologically oxidizable and

biologically inert material. COD determination has the advantage over BOD determination, in that, the result can be obtained

within 3 hours, where as it takes 5 days in BOD test. Principle:

The organic matter present in the sample gets oxidized completely by K2Cr2O7 in the

presence of H 2SO4 to produce CO2 and H2O. The excess of K2Cr2O7 remaining after the reaction is

titrated with F(NH4)2, (SO4)2 i.e., Ferrous Ammonium Sulphate (FAS). The dichromate consumed

gives the oxygen required for the oxidation of organic matter. Apparatus:

1. Reflux apparatus; 2. Burner/Heating mantle; 3. Burette; 4. Conical flask; 5. Pipette Reagents:

1. Standard Potassium Dichromate (0.25N)

2. Sulphuric Acid with Silver Sulphate

3. Standard Ferrous Ammonium Sulphate(0.1N)

4. Ferroin Indicator.

5. Mercuric Sulphate (HgSO4)



Procedure:

1. Place 0.4g Mercuric Sulphate in the reflux flask and add 20ml of sample and mix.

2. Then add 10ml of standard K2Cr2O7 solution and add slowly 30ml of concentrate H2SO4 containing Silver sulphate in it and mix it thoroughly.

3. Reflux this mixture for a minimum period of 1 hour. Cool and wash down the condenser

with distilled water.

4. Dilute the sample to make up 150ml and cool. Transfer this solution to a conical

flask And titrate excess K2Cr2O7 with 0.1 N FAS using ferroin indicator

5. Sharp colour change from bluish green to reddish brown indicates the end point.

6. Reflux the blank in the same manner using distilled water instead of the sample.

Observations:

Burette: 0.1N Ferrous Ammonium Sulphate (FAS) solution.

Conical flask : 150ml of sample

Indicator: Ferroin indicator

End Point: Bluish green to reddish brown.

Sample Details Volume of IBR FBR Vol. of FAS, COD of Sample

sample taken VR=FBR- IBR (mg/L)

(ml)

Water sample (B)

Blank solution (A)

Calculations:

Where ; Quantity of FAS added for blank solution = A (ml)

Quantity of FAS added for water sample = B (ml)

= ………………………….. mg/lt.



Results: The COD of waste water is = ……………….. mg/lt

Discussion:

Environmental significance:

1. The COD test is used extensively in the analysis of industrial wastes.

2. It is widely used in place of BOD in assessing the operation of treatment facility because

of the speed with which the result can be obtained.

3. It is useful to access strength of wastes which contain toxins and biologically resistant

organic substances.

Questions:

1. What is the difference between BOD and COD?

2. What are the other methods to determine the chemical oxygen demand of water sample?

Marks Obtained:





AIR QUALITY MONITORING

Introduction

The components of an air pollution monitoring system include the

-collection or sampling of pollutants both from the ambient air and from specific sources,

-the analysis or measurement of the pollutant concentrations, and

-the reporting and use of the information collected

Emissions data collected from point sources are used to determine compliance with air pollution

regulations, determine the effectiveness of air pollution control technology, evaluate production

efficiencies, and support scientific research.

The EPA has established ambient air monitoring methods for the criteria pollutants, as well as for

toxic organic (TO) compounds and inorganic (IO) compounds.

The methods specify precise procedures that must be followed for any monitoring activity related

to the compliance provisions of the Clean Air Act.

These procedures regulate sampling, analysis, calibration of instruments, and calculation of

emissions.

The concentration is expressed in terms of mass per unit volume, usually micrograms per cubic

meter (µg/m3).

MONITORING OF GASES AND PARTICULATES IN AMBIENT AIR

1. Objective

To measure the ambient concentrations of gases and particulate matter by using High Volume

Sampler (HVS).

2. Instruments

a. High volume sampler (HVS) b. Whatman filter paper c. Impingers

3. Principle

PM10 and TSPM are measured by passing air at flow rate of about 1 lpm through high efficiency

cyclone which retains the dust particles greater than 10 micron size and allow only fines (less than 10

micron particles) to reach the glass microfibre filter where these particles are retained. The

instrument provides instantaneous flow rate and the period of operation (on-time) for calculation of



air volume passed through the filter. Amount of particulates collected is determined by measuring the

change in weight of the cyclone cup and filter paper.

4. Reagents for gaseous pollutants a. 0.1 N Sodium tetra-chloratemercurate (SO2) b. Sodium

hydroxide and sodium arsanite (NO2)

5. Procedure

i. For particulates

a. Perform leak check of the instrument before starting the sample.

b. Filter paper need to be inspected for pin holes.

c. Filter conditioning need to be done at 20-25ºC temperature and less than 50% Relative Humidity.

d. Never fold filter completely.

e. Do not touch filters by dirty hands always use disposable hand gloves.

f. Under take regular cleaning of key components of the machine.

g. Ensure stable power supply to the machine. Do not leave loose contact of supply wire to the

machine.

h. Always fill up distilled water in manometer assembly.

i. Do not switch on and off machine using Timer Switch.

j. Clean impinge and rotameter regularly and also clean manifold once in two months.

k. Do not take flow reading immediately after switching on the machine. Give 5 minute for flow

stabilization and for heat up the blower components.

l. Always attach a new weighed cyclone cup with every filter change.

m. Do not switch on machine without filter paper

n. If machine is not expected to be operated within 48 hrs drain out the manometer water and store

machine with water in the manometer tank.

o. Do not run machine during rain in open atmosphere.

ii. For gaseous

The increasing general awareness of atmospheric pollution and its hazards to the health and well-

being of industrial workers, educational buildings, offices etc., is bound to result in greater stress on

accurate, reliable and frequent assessment of work place pollution and worker-exposure. Use

additionally impinge tray with HVS sampler simultaneously sample gaseous pollutants.

6. Calculation for particulates

a. Initial Manometer Reading =

b. Final Manometer Reading =

c. Initial Filter Paper Weight =



d. Final Filter Paper Weight =

e. Initial Cyclone Cup Weight =

f. Final Cyclone Cup Weight =

g. Total Suspended Particulate Matter Concentration =

INDOOR AIR QUALITY MONITORING

1. Objective To understand how to operate the instrument and also know the basic knowledge of

indoor air quality (IAQ) monitor.

2. Apparatus

Indoor air quality monitor (automatic sampler) for carbon monoxide (CO), carbon dioxide (CO2),

temperature and humidity.

3. Indoor Air Quality monitor

With 90% of our time spent indoors, determining the quality of the air we breathe indoors is essential

for good health and productivity. The IAQ monitor key indoor air quality indicators including CO2,

humidity, temperature and CO. Should these measurements fall outside recognized guidelines;

further tests can be made to suggest an appropriate course of action. For example, ventilation studies

show that as room temperatures rise above 75°F(24°C) the ability of occupants to concentrate can

drop by up to 50% and high levels of carbon dioxide will indicate poor ventilation that results in

drowsiness and perceived stuffiness. Both situations are very common and seriously affect

productivity. Over-ventilation wastes energy and results in increased building running costs. The

Surveyor range has been designed with the user in mind. Minimal training is required to use the

instruments as the intuitive menu system and display provide step-by-step guides for each operation

that are updated when smart probes are plugged in.

4. Steps for sampling

a. Prepare a sampling assembly.

b. Set the time constant depending upon the required averaging period.

c. Instrument can be switch on and it will display concentration.

d. Simultaneously instrument will start recording the concentration values in the memory card.

e. Using data transfer cable (ie. RS232 cable) can download data from instrument to personal

computers.




DETERMINATION OF SOUND LEVEL

Aim: This experiment aims at gaining experience with use of a Sound Level Meter for basic noise

level detection measurements.

Equipment: Sound level meter and calibrator, sound source, measuring tape, markers

Measurements using sound power source

1. Do the battery test and performance check of the SLM.

2. Set the sound power source in the centre of the class room and, using the wideband spectrum,

adjust the output to a convenient level.

3. Measure the noise level in dB(A) at 1m, 2m and 4m from the center of the source.

4. Determine the linear frequency spectrum at 2m from the center of the source.

5. Do not adjust the output setting! But do either part a) or part b)

a. relocate the sound source to a more reverberant space such as stair well or foyer OR

b. relocate the sound source to a less reverberant space such as in the open well away from

reflecting surfaces.

6. Measure the noise level in dB(A) at 1m, 2m and 4m from the center of the source.

Report

Produce a report summarizing the results of the measurements and include:

1. A summary table showing the change in sound pressure level with distance in the two

environments. Comment on your findings and compare with general guidelines on reduction

with distance from a source.

2. A calculation of the overall A weighted level and comparison with the value measured at that

same location.

3. A chart of the octave band frequency spectrum in terms of dB. Use the values for the A

weighting to calculate the A weighted frequency spectrum. Plot these A weighted values on the

chart and comment on the shape of the twp curves.



Sketch of measurement arrangements:

Distance 1m 2m 4m

Sound Pressure

Level, dB(A) in

classroom

Sound Pressure

Level, dB(A) in

alternate space

Comments:

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IMPORTANT POINTS



IMPORTANT POINTS

Documents

GLOBAL ACADEMY OF TECHNOLOGYLab Manual, ISO 14001 Environmental Management, Regulatory Standards for Drinking Water and Sewage disposal. 2. Clair Sawyer and Perry McCarty and Gene