Lab Manual on Water and Waste Water Analysis by Santosh Kumar Kharole

8/2/2019 Lab Manual on Water and Waste Water Analysis by Santosh Kumar Kharole

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UNIVERSITY INSTITUTE OF TECHNOLOGY, RAJIV GANDHIPROUDYOGIKI VISHWAVIDHYALAYA, BHOPAL

LABORATORY MANUAL

ENVIRONMENTAL ENGINEERING

(DEPARTMENT OF CIVIL ENGINEERING)

SAMPLING PROCEDURES FOR WATER & WASTE WATER ANALYSIS

1. Sampling

A sample has to representative and valid both in time and space. The parameters in the sample

at the time of analysis should have the same value and those at time and place of sampling. A

sample will be representative depending upon the sampling techniques and preservations. A

sample is valid if represents the true picture of water quality at the sampling point. Quality of

water depends on place, time and its estimation depends on frequency of sampling. Conditions

at each sample source vary widely and sampling programmed needs to be worked on the merits

of the source.

2. Frequency of Sampling

Quality of water, flowing or stagnant, seldom remains the same in time. The larger the number

of samples from which the mean is derived the narrower will be limits of the probable

difference between the observed and true value of the mean. In order to double the reliability ofa mean value, the number of samples must be increased four-fold, because confidence limits

are proportional to the square of the number of samples, hence a confidence between the

increase reliability of data measured by confidence limits and the cost of its collection has to be

reached.

Effluent or water quality changes depending on the mass inputs and changes in the rate of

water flow or on volume. Characteristics of water quality vary

(a)Randomly e.g. during from, spillages in factory and (b)

Cylindrically due to rainfall pattern. Also they vary with the production pattern in manufacture

process, on of samples to be collected from a distribution systems should be as under:

3. Number of samples

Population

served

Maximum interval

between successive

sampling

Minimum no. of sampling to the taken

from entire distribution system

Upto20000

20000-500000

50000-100000

More than 100000

one month

two week

four days

one day

One sample per 5000 of population per month

--- do----

--- do----

One sample per 10000 of population per month


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Frequency of sampling can be worked out as under:

Confidence level of an arithmetic mean of normally distributed values is the percentage of

occasions (p %) on which true mean may be expected to lie with in a given range of values.

The range in the confidence interval which is bounded by the confidence limits. Presume 95%

confidence limits at 10, and then the probability is that on 95% occasion out of 100, theobserved mean will not differ from the true mean by more than 10.Normally:

P % = x E : L = KS / N

Where S = Std. Deviation, K = Factor depending on p.

Table 1

If N 30, put students t in place of K.

4. Sampling Procedure:

The determinants fall into three groups:

(a) Conservative, not changing with time.(b) Non-conservative, change with time out can be.

(c) Stabilized for 24 hours by proper treatment

(d) Non-conservative, change rapidly with time and cannot be preserved e.g. temperature

, pH, D.O.

Table 2 gives the preservation required for some commonly required parameters.

Table No.2

Confidence

level%

99 98 95 90 80 68 50

K 2.58 2.38 2.96 1.64 1.2 1.0 6.67


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5. COMPOSITE SAMPLES

Parameter Container Preservative Max.holdingperiod

1 2 3 4

Acidity/Alkalinity

BOD

CalciumCOD

Colour

Cyanide

Do

Metales,total

Dissolved metals

Amm. Nitrogen

Kjeldahal

Nitrogen

Nitrate-Nitrite

Oil& Grease

Organic Carbon

Phenolics

Phosphorus

Sulphates

Sulphide

Silica

Glass

---do---

PlasticGlass

----------

----------

Glass

Plastic/Glass

--do

---do

--do

Glass/Plastic

-----------

Glass

----------

Glass

Plastic/Glass

----------

Plastic

Refrigeration

---do---

Not required2ml H2SO4/ 1 Ph-2

Refrigeration

PH 10 by NaOH

On site

5ml HNO3/1

40 fileration:3ml 1:1HNO3/ l

40 mgHgCl2 / liter

40oC

---do---

40 mgHgCl2/ liter

40oC

2ml/liter H2SO4

40oC

2ml H2SO4 /l- (pH-2)

1 g CuSO4 + H3Po4:

4.04oC

40mg MgCL2 /1-4oC

4oC

2mlZn Acetate/ 1

Filter on site then 4oC

24 hours

6 hours

------7 days

24 hours

24 hours

None

6 months

6 months

7 days

Unstable

7 days

24 days

7 days

24 hours

7 days

7 days

7 days

--do--


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It is a general practice to mix discrete samples lo form a composite sample.Time based

composite or weighted composite sample is one, when individual samples are mixed in

equal portions, or in portions according the flow at the time of sampling. Analysis of a

composite sample wills he the average over the time of sampling. This will not give any

indication of maximum or minimum values over the sampling period.

Manual sampling is economically reliable. Composite samples are not possible for DO,pH, temperature, CN, metals and bacteria. These changes with time or due to chemical

interactions.

Each sample should carry a tag or label as under:

(a)Source

(b)Date

(c)Time

(d)Preservation added

(e)Collectors identity

Polluted Liquid Sampling

When the liquid to be sampled contains oily or tarry matter or solids like those in sewage,

it is difficult to collect representative samples. At sewerage works, sampling should not

be done before screening. It should be done at a point in sewer where considerable

turbulence is present. Oily substances form a film over the liquid and special procedure

showed under these circumstances.

Sample for Physical and Chemical Analysis:

Samples should he collected in containers of Pyrex glass or other inert material like

polythene.

Sample bottles must be carefully cleaned before use. Glass bottles may be rinsed with a

chromic acid cleaning mixture, made by adding one liter of concentrated sulphuric acid

slowly with string to 35 ml saturated sodium dichromate solution, or with an alkaline

permanganate solution followed by an oxalic acid solution. After having been cleaned,

bottles must be rinsed thoroughly with tap water and then with distilled water.

About 2.5 liters of the sample is required for analysis prior to filling, the sampling bottle

should be rinsed out two or three times with water to be collected. Care should be taken to

obtain a sample that is truly representative of existing conditions and to handle it in sucha way that it does not deteriorate or become contaminated before it reaches the

laboratory.

The sample should reach the place of analysis within 72 hours of collection. The time

elapsed between collection and analysis should be recorded on the laboratory report.

Some determinations are likely to be affected by storage of samples. Walls of glass

containers are likely to absorb cations like aluminum, cadmium, chromium, Copper, Iron,

Lead, Manganese, Silver or Zinc which are best collected in a separate bottle and

acidified by concentrated hydrochloric or nitric acid to a pH approximately 3.5 to

minimize precipitation and absorption on the walls of the container.Certain parameters like to temperature, pH, dissolved gases like carbon di-oxide,

hydrogen sulphite, chlorine and oxygen may change significantly during transportation.

For this reason, determination of pH carbon di-oxide, dissolved oxygen and chlorine


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should be carried out on the spot. Hydrogen sulphide can be preserved by fixing it with

zinc acetate until the sample is ready for analysis.

Hot samples collected under pressure should be cooled while under pressure, Samples

from wells should be collected only after the well has been pumped for a sufficient time

to ensure that the sample will be representative of the ground water. For collection of

sample at different depths. Specific equipment should he used.

SAMPLING FROM A WATER WORKS SVSTME & DISTRIBUTION SYSTEM

In order to find out whether the processes of treatment are satisfactory, a number of

sampling points at different locations of water works system arc selected.

The samples from distribution system should be drawn from different mains and

periphery of the distributory system. For taking sample sterilized stand pipe must be used.

Before taking sample the pipe line should be hushed for a sufficient period 10 get arepresentative sample.

SAMPLEING FOR BACTERIOLOGICAL ANALYSIS

Sterilized glass bottles provided with ground glass stopper having an overlapping rim

should be used. The stopper and the neck of (he bottle should be protected by brown

paper. The sterilization is carried out in an autoclave at 1 kg/cm 2

Pressure for 15 minutes or two hours under steam and some space should be left in the

bottle after sample is collected, Dechlorination is necessary for chlorinated water

samples. For this, sodium thiosulpate should be added to the clean, dry sampling bottle

before sterilization in an amount to provide an approximate concentration of 100 mg/l in

the sample. This can be done by adding 0.2 ml of 10% thiosulphate solution to a 250 ml

bottle. The bottle is than sterilized by either dry or moist heal. A mini volume of 250 ml

should be taken for bacteriological exam.

PRESERVATION AND STORAGE

Water sample should be examined immediately after collection forever, this is seldom

practical and hence it is recommended that the samples should be preferable analyzed

within one hour after collection and in no case this time should exceed 24 hours. Duringtransit, the temperature of the sample should be maintained as close as possible to that of

the source of the sample, at the time of sampling. The time and temperature of storage of

all samples should be recorded since they will be considered in the interpretation of the

laboratory results. If they can not be analyzed within 24 hours the samples must be

preserved in ice; until analysis No sample is 111 for bacteriological analysis after 72

hours.

SAMPLING FOR BIOLOGICAL ANALYSIS

For this purpose, two samples should be collected in clean two liter wide mouthedbottles with a glass stopper or a bakelite screw cap. In making the collection the bottle.

Alter I he stopper is removed, is thrust as far as possible, mouth downward into dir water.

It is then inverted and allowed to fill. To another bottle add 5 ml of commercial formalic


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to every 100 ml of water sample immediately after collection Both the bottles should be

dispatched with the label on the sample stating the one with formalin

7.4 Preservation and storage

Water sample should be examined immediately after collection. However,

this is seldom practical and hence it is recommended that the sample shouldbe preferably analyzed within one hour after collection and in no cases this

time should extended 24 hour .During transits, the temperature of the

sample should be maintained as close as possible be that source of the

sample ,at the time of sampling .The time and temperature of storage of al

the sample should be recorded since they will be considered in the

interruption of the laboratory results.

If they can not analyzed within 24 hour ,the samples be preserved in ice

until analysis. No sample is fit for bacteriological analysis after 72 hours.

8. Sampling for Biological Analysis

For this purpose , two sample, should be collected in clean two liter wide

mouthed bottle with glass stopper or bakelite screw cap.

In making the collection, the bottle, after the stopper is removed, is thrust as

far as possible mouth downward into the water. It is than inverted and

allowed to fill. one bottle is stopped such .To another bottle ad 5 ml

commercial formalin to every 100 ml of water sample immediately after

collection . both the bottle should dispatched with the label on the sample

stating the one with in formation.

It two liter of sample could not be collected even 200 ml of the sample may

be collected as above the formation added to one sample (0 ml of formation

added to 200 ml of water)

STANDER TESTS

The standard test that are employed in the analysis of water are as follows :

1. Physical Examination: The parameter tested are temperature,

turbidity, colour, and odour.

2. Chemical Examination:

a) this include test for chemicals that affects the health of the

consumers and the portability of the water viz. pH ,acidity, manganese,

copper, Zink, aluminium, sulphates ,fluoride ,colloids, total dissolved and

suspended solids.b) Test for efficiency of treatment viz chloride free and combined

residual chlorine ,coagulants dosages.

c) Test for chemical which are indicators of pollution such as total

nitrogen and nitrogen in various forms like ammonia, nitrite, phosphate,

dissolved oxygen and BOD.

d) Test for TOXIS chemical substance lead, arsenic, mercury,

selenium, chromium, cyanide, pesticides and hydrocarbons and

e) Test of radio activity

3. Bacteriological Examination: This comprise of plate count, coli

form count tests for fecal streptococci clostridium and salmonella.

4. Biological Examination: Microscopic tests for identification and

enumeration of micro organism other then bacteria are included in this

category.


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5. Schedule of tests: The schedule of laboratory test followed by a

particular undertaking will very with the size of plant and character of water

treated, tough the ordinary plant the minimum schedule should include

turbidity, color, alkalinity, pH, hardness, residual chloride, bacterial count at37*C and coli form bacteria number, both presumptive and confirmed.

Occasionally specia tests may be necessary such as residual alum ,

iron, and manganese tests and odore and other residual chlorine

should be tested at each major stage of treatment .Chlorine demand

tests should be carried out n row water.

METHOD OF EXAMINATION

The physical, chemical, bacteriological and biological procedure for

analytic laboratory examinations given in the manual of methods for

the examinations of water, sewage and industrial wastes published

by the Indian council ofMedical Research are to be followed. for procedure reading trace

and other element not covered by ICMR, the procedure

recommended in the W.H. O. publication International Standard for

Drinking Water. Third Edition (1971) may be followed.

Conformity to standard analytical methods is important of the result

of the test carried out by different laboratories are to be meaningful.

1. Reporting of results:

Specimen forms for reporting results of a short chemical

examination, a complete chemical examination and bacteriological

examinations of water, are given in appendix. For purpose of

uniformity standard expression should be clearly stated in the report.

The expression part per million (ppm), still used to express chemical

concentration, should be replaced by milligram per liter(mg/l) ,

which is much more appropriate, unless their special need to some

other chemicals concentration unit like miliequivalent per

liter(per me/l) of microgram of several anions or cations

responsible for imparting a particular characteristic to the water like

hardness.

Volume are expressed in milli-liters (ml) and to temperature in

degree is centigrade (*C) . The total number of micro organismdeveloping on solid media should be given in significant numbers

per ml of water, the medium, time and temperature of incubation

being started. The number of coli form organism and other organism

indicator of pollution should be expressed in term of Most Probable

Number(MPN)per 100 ml or as determined number obtained by

direct plotting procedures. In biological examinations, the

concentration of organisms per ml of sample is expressed in many

instances as a simple more usually in term of a real standard units or

numerical count. Occasionallythe result is express in mg/l, but

volumetric standard units.

Reporting analytical results of a particular examination should beincluding the proper use of significant figures and the expression of

confidence limit, where appropriate.


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1.2 Physical and chemical standard for drinking water in India

S.No. Characterstics Acceptable Cause forrejection

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12..

Turbidity ( units on J. T. U. scale )

Colour (units on platinum cobalt scale )

Taste and Odour

pH

Total dissolved solids (mg/l)

Total hardness (mg/l) (as CaCO3)

Chlorides (as Cl ) (mg/l)

Sulphates (as SO4 ) (mg/l)

Fluorides (as F) (mg/l)

Nitrates (as NO3) (mg/l)

Calcium (as Ca) (mg/l)

Magnesium (as Mg) (mg/l)

2.5

5.00

Unobjectionable

7.0 to 8.5

500

200

200

200

1.0

45

75

30

10

25

Unobjectionable

6.5 to 9.2

1500

600

1000

400

1.5

45

200

150

If there are 250 mg/l of sulphates, Mg contents can be increased to a maximum of 125mg/l with the reduction of sulphate at the rate of 1 unit per every 2.5 units of sulphates

13.

14.

15

16.

17.

18.

19.

Iron (as Fe) (mg/l)

Manganese (as Mn) (mg/l)

Copper (as Cu) (mg/l)

Zinc (as Zn) (mg/l)

Phenolic compounds (as phenol ) (mg/l)

Anionic detergents (as MBAS) (mg/l)

Mineral oil (mg/l)

0.1

0.05

0.5

5.00

0.001

0.2

1.0

0.5

1.5

15.0

0.002

1.0

TOXIC MATERIAL

20. Arsenic (as As) (mg/1) 0.05 0.05

21. Cadmium (as Cd) (mg/1) 0.0 1 0.0 1


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22. Chromium (as hexavalent Cr) (mg/1) 0.05 0.05

23. Cyanides (as CN) (mg/1) 0.05 0.05

24. Lead (as Pd) (mg/1) 0.1 0.1

25. Selinium (as Se) (mg/1) 0.01 0.01

26. Mercury (total as Hg) (mg/1) 0.001 0.001

27. Polynuclear aromatic hydrocarbons

(PAH)

0.1 / ug /l 0.2/ ug /l

RADIO ACTIVITY

28. Gross Alpha activity 3 pCi /1 3 p Ci/ 1

29. Gross Beta activity

Pci = pico curie

30 pCi / 1 30 p Ci/ l

Notes:

1*. The figures indicated under the column "acceptable1 are the limits upload which the

water is generally acceptable to the consumers.

2* Figures in excess of those mentioned under 'acccpiablc1 render the water not

acceptable but still may be tolerated in the absence of alternative and better source

but up to the limits indicated under column cause for rejection1 above which the

supply will have to be rejected.

3. It is possible that come mine and spring waters may exceed these radio activity

limits and in such eases. It is a necessary to analyze the individual radio nuclides

in order to assess the acceptability or otherwise for public consumption.

APPENDIX

TEST CHARACTERSTICS FOR DRINKING WATER


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S.No Substance of

characteristic

W.H.O

Guideline

value (1885)

CPHEEO Recommendation

1991

IS : 10500 : 1991

Desirable

value

Maximum

Tolerable value

Desirable

value

Maximum

Tolerablevalue

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Turbidity

Colour

Taste

Odour

pH value

Total dissolved

solids (mg/l)

Total hardness(as CaCO3mg/l)

Iron (as mg/l)

Chlorides(as CI mg/l)

Residual free

chlorine (mg/l)

Calcium(as Ca mg/l)

5 NTU

15 TCU

I.O

I.O

6.5 8.5

1000

500

0.3

250

2.5 NTU

5.0

U.O

U.O

7.5 8.5

500

200

0.10

200

75

10.0 JTU

25.0

6.5 9.2

1500

800

1.0

1000

200

5 NTU

5 Hazen

U.O

U.O

6.5 8.5

500

300

0.3

250

0.2

75

10 NTU

25 Hazen

6.5 8.5

2000

600

1.0

1000

200


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12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

Copper (as Cu mg/l)

Magnesium (as Mn mg/l)

Sulphate (as SO4 mg/l)

Nitrate (as NO3 mg/l)

Fluoride (as F mg/l)

Phynolic compounds(as C6H5OH mg/l)

Mercury (as Hg mg/l)

Cadmium (as Cd mg/l)

Selenium (as Se mg/l)

Arsenic (as As mg/l)

Lead (as Pb mg/l)

Zinc (as Zn mg/l)

Cyanide (as CN mg/l)

Anionic detergents(as MBAS mg/l)

Chromium (as Cr mg/l)

Polynuclear aeromatic

hydrocarbons (mg/l)

Pesticides mg/l

Radio active materials

(a) - emitters Ba/l

(b) -emitters Pci/l

Alkalinity mg/l

Aluminium (as Al mg/l)

Boron mg/l

Mineral oil mg/l

Sodium mg/l

1.0

0.1

400

45

1.5

0.001

0.005

0.01

0.05

0.05

5.0

0.10

0.05

0.1

1.00

0.2

200

0.05

0.05

200

45

1

0.001

0.001

0.01

0.01

0.05

0.10

0.05

0.05

0.2

3.0

1.5

0.5

400

100

1.5

0.005

0.001

0.05

0.1

200

45

1

0.001

0.001

0.01

0.01

0.05

0.05

5.0

0.05

0.2

0.05

Absent

0.1

1.0

200

0.03

1.0

0.01

1.5

0.3

400

100

1.5

0.002

0.001

0.01

0.01

0.05

0.05

15.0

0.05

1.0

0.05

0.001

600

0.2

5.0

0.03


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EFFLUENT STANDARDS

These standards fix the limits of wastewater (after treatment) depending upon the mode of

final disposal viz :

a) Discharge into inland surface water.

b) Discharge on land for irrigation purpose.

c) Discharge into public sewers.

Acceptable limits according to IS-2490-1963, 1S-3307-1965 and 1S-3306-1965 are:

S.No. Characteristics Standards for water discharge

Into inland

surface water

On land for

irrigation purpose

Into public

sewers

1 2 3 4 5

1. R.O. (for 5 days at

20aC)30-100 mg/l 500 mg/1 500 mg/1

2. Suspended solids 100 mg/l -- 600 mg/1

3. pH 5.5-9.0 5.5-9.0 5.5-9.0

4. Temperature 4C - 45C

5. Oil and grease 16mg/l 30 mg/1 1 00 mg/1

6. Cunides 0.2 mg/1 - 2.0 mg/1

7. Sulphides 2.0 mg/1 - -

8. Total residua! chlorine 1.0 mg/l - -

9. Flouride 2.0mg/l - -

10, Arsenic 1.0 mg/1 - -

11. Total dissolved solids - 2100 mg/1 2100 mg/1

12. Sulphates - 1000mg/l 1000mg/1

13. Chlorides - 600 mg/1 600 mg/1

14. Sodium % - 60% 60%

15. Boron - 2 mg/1 2 mg/1


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16. Gross and radio

activity

- 10-9/uc/l 10-7/uc/ml

17. Gross and radioactivity

10-8 /cu/ml 10-3 /cu/ml 10-6 /cu/ml

18. Lead - - 1 mg/1

19. Copper - - 3 mg/1

20. Zinc - - 15 mg/1

21, Hexavalent compound - - 2mg/l

22. Nickel - - 2 mg/1

23. Phenolic compound - - 5mg/l

24. Amonical nitrogen - - 50 mg/1


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TOXIC MATERIAL

20. Arsenic (as As) {nig/1) 0.05 0.05

21. Cadmium (as Cd) (mg/1) 0.0 1 0.0 1

22. Chromium (as hexavalent Cr) (mg/1) 0.05 0.05

23. Cyanides (as CN) (mg/1) 0.05 0.05

24. Lead (as Pd) (mg/1) 0.1 0.1

25. Selenium (as Se) (mg/1) 0.001 0.01

26. Mercury (total as Hg) (mg/1) 0.003 0.001

27. Polynuclear aromatic hydrocarbons 0.1/ug/1 0.2/ug/1

(PAH)

RADIO ACTIVITY

28. Gross Alpha activity 3p Ci/ 1 3p Ci/ 1

29, Gross Beta activity 30p Ci/ 1 30pCi/l

Pci = pico curie

Notes:

1*. The figures indicated under the column "acceptable1 are the limits upload which the

water is generally acceptable to the consumers.

2* Figures in excess of those mentioned under 'acccpiablc1 render the water not

acceptable but still may be tolerated in the absence of alternative and better source but up

to the limits indicated under column cause for rejection1 above which the supply will

have to be rejected.

3- It is possible that come mine and spring waters may exceed these radio activity

limits and in such eases. It is a necessary to analyze the individual radio nuclides in order

to assess the acceptability or otherwise for public consumption.

17


15/58

1.2 Physical and chemical standard for drinking water in India.

S.No.

Characterstics Acceptabl

e

Cause

forrejection

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12..

Turbidity ( units on J. T. U. scale )

Colour (units on platinum cobalt scale )

Taste and Odour

pH

Total dissolved solids (mg/l)

Total hardness (mg/l) (as CaCO3)

Chlorides (as SO4) (mg/l)

Sulphates (as SO4) (mg/l)

Fluorides (as F) (mg/l)

Nitrates (as NO3) (mg/l)

Calcium (as Ca) (mg/l)

Magnesium (as Mg) (mg/l)

2.5

5.00

Unobjectionable

7.0 to 8.5

500

200

200

200

1.0

45

75

30

10

25

Unobjectionable

6.5 to 9.2

1500

600

1000

400

1.5

45

200

150

if there are 250 mg/l of sulphates, Mg contents can be increased to a maximum of125 mg/l with the reduction of sulphate at the rate of 1 unit per every 2.5 units of

sulphates

13.

14.

15

16.

17.

18.

19.

Iron (as Fe) (mg/l)

Manganese (as Mn) (mg/l)

Copper (as Cu) (mg/l)

Zinc (as Zn) (mg/l)

Phenolic compounds (as phenol ) (mg/l)

Anionic detergents (as MBAS) (mg/l)

Mineral oil (mg/l)

0.1

0.05

0.5

5.00

0.001

0.2

1.0

0.5

1.5

15.0

0.002

1.0

26. Chromium (as Cr mg/l) 0.05 0.05 0.05 0.05


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27.

28.

29.

30.

31.

32.

33.

34.

Polynuclear aeromatic

hydrocarbons (mg/l)

Pesticides mg/l

Radio active materials

a) emitters Ba/l

b) emitters Pci/l

Alkalinity mg/l

Aluminium (as AI mg/l)

Boron mg/l

Mineral oil mg/l

Sodium mg/l

0.1

1.00

0.2

200

0.2

3.0

Absent

0.1

1.0

200

0.03

1.0

0.01

0.001

600

0.2

5.0

0.03


17/58

APPENDIX

TEST CHARACTERSTICS FOR DRINKING WATER

S.No Substance of

characteristic

W.H.O

Guideline

value

(1885)

CPHEEO Recomm.

1991

IS : 10500 : 1991

Desirable

valueMaximum

Tolerable

value

Desirable

valueMaximum

Tolerable

value

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Turbidity

Colour

Taste

Odour

pH value

Total dissolved

solids (mg/l)

Total hardness

(as CaCO3mg/l)

Iron (as mg/l)

Chlorides

(as CI mg/l)

Residual free

chlorine (mg/l)

Calcium

(as Ca mg/l)

5 NTU

15 TCU

I.O

I.O

6.5 8.5

1000

500

0.3

250

2.5 NTU

5.0

U.O

U.O

7.5 8.5

500

200

0.10

200

75

10.0 JTU

25.0

6.5 9.2

1500

800

1.0

1000

200

5 NTU

5 Hazen

U.O

U.O

6.5 8.5

500

300

0.3

250

0.2

75

10 NTU

25 Hazen

6.5 8.5

2000

600

1.0

1000

200

12.

13.

Copper (as Cu mg/l)

Magnesium (as Mn mg/l)

1.0

0.1

0.05

0.05

1.5

0.5

0.05

0.1

1.5

0.3


18/58

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

Sulphate (as SO4 mg/l)

Nitrate (as NO3 mg/l)

Fluoride (as F mg/l)

Phynolic compounds

(as C6H5OH mg/l)

Mercury (as Hg mg/l)

Cadmium (as Cd mg/l)

Selenium (as Se mg/l)

Arsenic (as As mg/l)

Lead (as Pb mg/l)

Zinc (as Zn mg/l)

Cyanide (as CN mg/l)

Anionic detergents

(as MBAS mg/l)

400

45

1.5

0.001

0.005

0.01

0.05

0.05

5.0

0.10

200

45

1

0.001

0.001

0.01

0.01

0.05

0.10

0.05

400

100

1.5

0.005

0.001

200

45

1

0.001

0.001

0.01

0.01

0.05

0.05

5.0

0.05

0.2

400

100

1.5

0.002

0.001

0.01

0.01

0.05

0.05

15.0

0.05

1.0

BACTERIOLOGICAL STANDARDS

1. Water entering the distribution system

Coli form count in any sample of 100 should be zero. A sample of the water entering the

distribution system the docs not conform to this standard calls for an immediate

investigation into both the efficiency of the purification process and the method of

sampling.

2. Water in the distribution system shall satisfy all three criteria indicated

below:- B.Coli count in 100 ml of any sample should be zero,


19/58

- Colifom organisms not more than 10 per 100ml shall be present in any sample.

- Coli form organisms should not be detectable in 10 nil of any two consecutive

samples or more than 50% of the sample collected for the year.

3. Individual or small community supplies

B. Coil count should be zero in any sample of 100 ml and a coli form organisms

should not be more than 3 per 100 ml. (If repeated samples show the presence of coli

form organisms, steps should be taken to discover and remove the source of the pollution.

If coli form exceed 3 per 100 ml, the supply should be disinfected).

VIROLOG1CAL ASPECTS

0.5 mg/i of free chloride residual for one hour is sufficient to inactive virus, even

in water that was originally polluted. This free chloride residual is to be insisted in all

disinfected supplies in areas suspected of endcmicity of infections hepatitis to take care ofthe safety of the supply from virus point of view which incidentally takes care of the

safety from the bacteriological point of view as well. For other areas mg/I of free chlorine

residual for half an hour should be insisted-

SAMPLING: INSTRUCTION & DETAILS

INTRODUCTION

For the proper working of plants, effluent with in prescribed quality, collection of

proper sample and its analysis is a must, the present experiment aims at describing important

methodology, preservation techniques and frequency. A sample has to be representative and

valid both in time and space. The parameters in the sample at the time of analysis should have

the same values as those at the time and place of sampling. A sample will be representative

depending upon the sampling techniques and preservation. A sample is valid if it _represents

_the true picture of water/waste water quality at the sampling point. Quality of water depends

on place, time and its estimation depends on frequency of sampling. Conditions at each sample

source very widely and sampling programmed needs to be worked on the merits of the source.

FREQUENCY OF SAMPLING

Quality of water, flowing or stagnant, seldom, remains the same in time. The longer thenumber of samples from which the mean is derived the narrower will be tin: limits of the

probable difference between the observed and true value of the mean. In order to double the


20/58

reliability of a mean value, the number of samples must hi: increased fourfold, because

confidence limits are proportional to the square of the number of samples, hence a confidence

between the increased reliability of data measured by confidence limits and the cost of its

collection has to be reached.

Effluent or waste water quality changes depending on the mass inputs and changes in

rate of water flow or on volume. Characteristics of water quality vary (a) randomly e.g. during

form, spillages in factory, and (b) cyclically due to rain

Fall pattern. Also they vary with the production pattern in manufacture process, or

depending upon the sources, say a river or a lake.

The minimum number of samples to be collected from a distribution system should be as under

:

Table No. 1

Population served Maximum interval between

successive sampling

Minimum NO. of samples

to be taken from entire

distribution system

up to 20000 One Month One sample per 5000 of

population per month

20000 to 50000 Two weeks ----do----

50000 to 100000 Four Days ------do-----

More than 100000 One Day One sample per 10000 of

population per month

SAMPLING PROCEDURE

Procedure will depend on the type of sample i.e. its quality and & grouped accordingly

a) Non-conservative changes with time.

b) Stabilized for 24 hours by proper treatment.

c) Non-conservative, i.e. changes rapidly with time and can not he preserved e.g.

Temperature, pH, DO requiring fixation or determination on site.

Table2: Gives the preservation required for some only requiredparameters.

Table:2


21/58

COMPOSITE SAMPLE

It is a general practice to mix discrete samples lo form a composite sample.

Parameter Container Preservative Max.

holding

period

1 2 3 4

Acidity/Alkalinity

BODCalcium

COD

Colour

Cyanide

Do

Metales,total

Dissolved metals

Amm. Nitrogen

Kjeldahal

Nitrogen

Nitrate-Nitrite

Oil& Grease

Organic Carbon

Phenolics

Phosphorus

Sulphates

Sulphide

Silica

Glass

---do---Plastic

Glass

----------

----------

Glass

Plastic/Glass

--do

---do

--do

Glass/Plastic

----------

Glass

-------------

Glass

Plastic/Glass

-----------

Plastic

Refrigeration

---do---Not required

2ml H2SO4/ 1 pH-2

Refrigeration

pH 10 by NaOH

On site

5ml HNO3/1

40 filerate:3ml 1:1

HNO3/ l

40 mgHgCl2 / liter

40oC

---do---

40 mgHgCl2/ liter

40oC

2ml/liter H2SO4

-40o

C2ml H2SO4 / l- (pH-2)

1 g CuSO4 + H3Po4:

4.04oC

40mg MgCL2 /1-4oC

4oC

2mlZn Acetate/ 1

Filter on site then 4o

C

24 hours

6 hours------

7 days

24 hours

24 hours

None

6 months

6 months

7 days

Unstable

7 days

24 days

7 days

24 hours

7 days

7 days

7 days

--do--


22/58

Time based composite or weighted composite sample is one, when individual samples are

mixed in equal portions, or in portions according the flow at the time of sampling. Analysis of a

composite sample wills he the average over the time of sampling. This will not give any

indication of maximum or minimum values over the sampling period.

Manual sampling is economically reliable. Composite samples are nut possible for DO,

pH temperature. CN, metals and bacteria. These change with time or due to chemical inter-

actions. Each sample thus collected should carry information such as source, time of collection,

preservative added, collector's identity and other useful information at site.

SAMPLING FOR PHYSICAL AND CHEMICAL ANALYSIS

Samples should he collected in containers of Pyrex glass or other inert material like

polythene. Sample bottle must be carefully cleaned before use. Glass bottles may be rinsed with

a chromic acid cleaning mixture, made by adding one liter of concentrated sulphuric acid

slowly with string to 35 ml saturated sodium dichromate solution, or with an alkaline

paramagnet solution foil wed by an oxalic acid solution. After having cleaned, bottles must be

rinsed thoroughly with tap water and then with distilled water.

About 2 5 liters of the sample is required for analysis Prior to filling the sampling

bottle should be rinsed out two or three times with water to be collected. Care should be taken

to obtain a sample that is truly representative of existing s and to handle it in .such a way that it

does not deteriorate or become contaminated before it reaches the laboratory.

The sample should reach the plate of analysis within 72 hours of collection. The time

elapsed between collection and analysis should be recorded on the laboratory report.

Some determinations are likely to be affected by storage of samples. Walls of glass containers

are likely lo absorb cations like aluminum cadmium, chromium. Copper, Iron, Lead,

Manganese. Silver or Zinc which arc best collected in a separate bottle and acidified by

concentrated hydrochloric or nitric acid to a pH approximately 3.5 to minimize precipitation

and absorption on the walls of he container. Hot samples collected under pressure should be

cooled while under pressure, Samples from wells should be collected only after the well has

been pumped for a sufficient time to ensure that the sample will be representative of the ground

water. For collection of sample at different depths. Specific equipment should he used.


23/58

SAMPLING FROM A WATER WORKS SYSTEM & DISTRIBUTION SYSTEM

In order to find out whether the processes of treatment are satisfactory, a number of

sampling points at different locations of water works system arc selected.

The samples from distribution system should be drawn from different mains and

periphery of the distributors system. For taking sample sterilized stand pipe must be used.

Before taking sample the pipe line should be hushed for a sufficient period 10 get a

representative sample.

SAMPLEING FOR BACTERIOLOGICAL ANALYSIS

Sterilized glass bottles provided with ground glass stopper having an overlapping rim

should be used. The stopper and the neck of (he bottle should be protected by brown paper. The

sterilization is carried out in an autoclave at 1 kg/cm 2

Pressure for 15 minutes or two hours under steam and some space should be left in the bottle

after sample is collected, Dechlorination is necessary for chlorinated water samples. For this,

sodium thiosulpate should be added to the clean, dry sampling bottle before sterilization in an

amount to provide an approximate concentration of 100 mg/l in the sample. This can be done

by adding 0.2 ml of 10% thiosulphate solution to a 250 ml bottle. The bottle is than sterilized

by either dry or moist heal. A mini volume of 250 ml should be taken for bacteriological exam.

PRESERVATION AND STORAGE

Water sample should be examined immediately after collection forever, this is seldom

practical and hence it is recommended that the samples should be preferable analyzed within

one hour after collection and in no case this time should exceed 24 hours. During transit, the

temperature of the sample should be maintained as close as possible to that of the source of the

sample, at the time of sampling. The time and temperature of storage of all samples should be

recorded since they will be considered in the interpretation of the laboratory results. If they can

not be analyzed within 24 hours the samples must be preserved in ice; until analysis No

sample is 111 for bacteriological analysis after 72 hours.

SAMPLING FOR BIOLOGICAL ANALYSIS


24/58

For this purpose, two samples should be collected in clean two liter wide mouthed

bottles with a glass stopper or a bakelite screw cap. In making the collection the bottle. Alter I

he stopper is removed, is thrust as far as possible, mouth downward into dir water. It is then

inverted and allowed to fill. To another bottle add 5 ml of commercial formalic to every 100 ml

of water sample immediately after collection both the bottles should be dispatched with the

label on the sample stating the one with formalin.

EXPERIMENT No. 1

pH -VALUEpH -VALUE

OBJECTOBJECT

To determine the pH value of given sample of water. To calculate the dose of

chemical for adjusting the pH to a specific value for treating 10 MLD of water.

APPARATUSAPPARATUS

Burette, Pipette, Conical flask and Glazed tile.

REAGENTSREAGENTS

0.02 N NaOH solution, Universal pH-indicator and pH paper.

THEORYTHEORY

pH is a term used rather universally to express the intensity of the acid oralkaline condition of a solution. More exactly, it is a way of expressing the


25/58

hydrogen-ion-concentration, as a number, which indicate the logarithm or

reciprocal of hydrogen-ion-concentration.

The concept of pH evolves from a series of developments that led to a fuller

understanding of acids and bases. Water containing no acid or alkali has a pH

value of 7, which is termed the neutral pH-value, and pH values 1 to 7 indicate

acidic and 7 to 14 indicate alkalinity.

The hydrogen electrode was found to be a very suitable device for measuring

hydrogen-ion-concentration, with its uses, it was found that pure water

dissociates to yield a concentration of hydrogen ions equal to 10-7 mole / litre.

H2O = H+ + OH-

Since water dissociates to produce one hydroxyl ion for each hydrogen ion, it is

obvious that 10-7 mole of hydroxyl ion is produced simultaneously. Applying

Law of Mass Action,

[H+] [OH ] = K

[H2O]

But, since the consumption of water is so extremely large and is diminished, so

very little by the slight degree if ionization. It may be considered as constant

and the above equation can be rewritten as [H+] [OH-] = Kw , add for pure

water at about 25 C -

[H+] [OH-] = 10-14 (Ion Product for Water)

Hence, for neutral water -

[H+] = 10-7 and [OH ] = 10-7

Expression of Hydrogen-ion concentration in terms of molar concentration is

rather cumbersome. In order to overcome this difficulty, Sorenson proposed to

express such values in terms of their negative logarithms and designated such

values as pHx, this x symbol has been superseded by the simple designation pH.

This term is represented by-


26/58

pH = -log [H+] or pH = log 1/ [H+]

pH-scale is usually represented as ranging from 0 to 14 with pH-7 representing

the absolute neutrality.

Acid Range Alkaline Range

0 7 14

It is important to remember that the [OH-] or [H] can never be reduced to zero,

no matter how acidic or basic the solution may be.

MEHTODS OF DETERMINATIONMEHTODS OF DETERMINATION

pH can be determined by the following two methods-

1. Electrometric Method

2. Colorimetric Method

ELECTROMETRIC GLASS ELECTRODE METHODELECTROMETRIC GLASS ELECTRODE METHOD

THEORY OF TESTTHEORY OF TEST

pH is a measure of the relative acidity or alkalinity of water. It may be measured

by determining with a potentiometer the voltage developed by two electrodes,

which are in contact with the solution. The voltage of one electrode known as

calomel half-cell is fixed. While the voltage of the other electrode varies with

the pH of the sample. The glass electrodes system is based on the fact that a

change of 1 pH unit produces an electrical charge of 59.1 milivolts at 25C and

is the most accurate method for determining the pH of a wide variety of

solution.

COLORIMETRIC METHODCOLORIMETRIC METHOD

THEORY OF TESTTHEORY OF TEST

Colorimetric method depends on the use of an indicator whose colour in

solution is characteristics of the pH values of the solution. The colour produced

is compared in a pH colour comparator with standards.

PROCEDUREPROCEDURE

(a) Electrometric MethodElectrometric Method


27/58

Standardize the pH electrometer by using a buffer solution of known pH

approaching that of the sample, and adjust the temperature correction.

The glass electrode and the calomel electrode should be thoroughly

wetted and prepared for use in accordance with the manufacturers

instructions. Insert the glass electrode in the water sample and read the

pH directly on the dial of the instrument.

(b) Colorimetric MethodColorimetric Method

Place 10 ml of the sample into each of the two or three tubes provided wit

the pH colour comparator. To one tube add the appropriate quantity of theindicator solution. Place the tubes in the comparator, compare the colour

with the standards and read the pH. Directions for making the

determination of pH will be found with the particular pH colour

comparator beings used.

(c) Adjustment of pHAdjustment of pH

(1) Take 20 ml of sample and determine its initial pH by Colorimetric

Method.

(2)Add NaOH to the above sample so as to raise its pH to 10 or 11.

(3)Note the volume of NOH required.

(4)Take two concurrent readings.

OBSERVATIONSOBSERVATIONS

S. No. Volume of

Sample

Initial Burette

Reading

Final Burette

Reading

Volume of

NaOH (cc)

1.

2.

3.

4.

5.


28/58


29/58

In disinfection of water by Chlorine, pH again plays an important role. The

action of chlorine as disinfectant is maximum in a specific pH-range, so for

achieving an efficient disinfection that pH is to be maintained.

In water softening by lime soda process the process is controlled in part by the

test for pH.

Corrosiveness of water is a function of pH and can often be corrected by

decreasing the acid intensity by addition of alkali, which is usually controlled

by determination of pH-value.

Similarly, the deposition or dissolving of scale or pipes can be controlled by

changing the reaction of alkalinity and pH value by addition of lime or soda ash,

also controlled by pH-determinations.

In sewage and industrial waste treatment employing biological processes, pH

must be controlled within a range favourable to the particular organisms

involved, chemical processes used to coagulate sewages or industrial waste, de-water sludge or oxidize certain substances, such as cyanide ion, required that the

pH be controlled within rather narrow limits.

EXPERIMENT No. 2

ACIDITY

OBJECTOBJECT

To determine the acidity of the given sample of water.

APPARATUSAPPARATUSBurette, Pipette, Conical flask and Glazed tile.

REAGENTSREAGENTS

0.02N NaOH solution, Methyl orange solution and Phenolphthalein solution.


30/58

THEORYTHEORY

The acidity of water may be used by presence of uncombined carbon-di-oxide,

mineral acids and salts of strong acid and weak bases. It is defined as thecapacity of a solution to neutralize a standard alkali.

It can be noted that for carbonic acid the starchiometric end point is not reached

until the pH has been raised to about 8.5 which indicates that all waters, having

a pH lower that 8.5 contains acidity. Usually, the phenolphthalein end point at

pH 8.2 to 8.4 is taken as the reference point. Inspection of curve further

indicates that at pH 7.0 considerable carbon-di-oxide remains to be neutralized

but alone CO2 will not depress the pH below a value of about 4.5

Considering the nature of the curve which is for a strong acid, it may be

concluded that neutralization of acid is essentially complete at pH 4.5. It is

incidentally, the methyl orange end point. Thus, it becomes obvious that the

acidity of neutral water is caused by carbon dioxide or by strong mineral acids.

Titration to methyl orange end point (pH = 4.5) is defined as the acidity which

gives a measures of relatively strong acids such as mineral acids and titration to

the phenolphthalein end point (pH = 8.3) is defined as totally acidity and it

includes also the weak acids, acids salts and some acidity due to hydrolysis.

1 2 3 4 5 6 7 8 9 10 11

Practical Range of

Mineral

Range of CO2 Acidity

PROCEDURE

(a) Total Acidity

Its determination should be made on spot; on a fresh sample collected in a bottle

and stoppered immediately to prevent escape of carbon dioxide. Take 50 ml to

100 ml of the sample in an Erlenmeyer flask, add 3 drops of phenolphthalein

indicator and titrate over a white surface with 0.02 N NaOH until faint colour

appears.


31/58

(b) Mineral Acid Acidity

Take 50 ml. or 100 ml of the sample in an Erlenmeyer flask, add 2 drops of

Methyl orange indicator, and titrate over a white surface with 0.02 N NaOH

until colour changes to faint orange. Brome-Cresol green indicator can also be

used in lace of methyl orange; it gives a sharp end point.

OBSERVATIONSOBSERVATIONS

(B) Mineral Acidity - Indicator methyl orangeMineral Acidity - Indicator methyl orange

S. No. Volume of

Sample

Initial Burette

Reading

Final Burette

Reading

Volume of

NaOH

required

(A)Total Acidity - Indicator phenolphthalein

1. .

2.

3.

4.

5.

S. No. Volume of

Sample

Initial Burette

Reading

Final Burette

Reading

Volume of

NaOH required

1.

2.

3.

4.

5.


32/58

CALCULATIONCALCULATION

(a) Total Acidity

Mg / lt. total acidity as CaCO3 =

= ml. 0.02 N NaOH x 1000 x 50 =

ml. of Sample

(b) Mineral acid acidity

Mg / lt. total mineral acid acidity =

= ml. 0.02 N NaOHx 1000 x 50 =

ml. of Sample

RESULTRESULT

The total acidity of sample B with initial pH.. .is found to be mg/lt. and

mineral acidity is mg / lt. The acidity of sample A (Tap Water) is mg

/ lt. The total acidity is due to mineral acidity & weak acids. For pH range more

than 8.5 the acidity due to OHions


33/58

SIGNIFICANCE

Acidity is of little concern from a statutory or public health view point , carbon

dioxide is present in malt and carbonate beverages in concentration greatly in

excess of any concentration known In natural waters , and no deleterious effects

due to the carbon dioxide have been recognized . Water that contains mineral

acidity is usually so unpalatable that problems related to human consumption

are non-existent.

Acid water is of concern to Sanitary engineer because of their corrosive

characteristics and the expenses involved in removing or controlling the

corrosion producing substances. The corrosive factor in most water is carbon

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

be reckoned with water softening problems where the lime or lime soda ash

method is employed.


34/58

EXPERIMENT No . 3

ALKALINITY

OBJECT

To determinate alkalinity of given sample of water.

APPARATUS

Burette, Pipette, Conical flask and Glazed tile.

REAGENTS

0.02 N H2SO4 solution, Phenolphthalein indicator and Methyl orange indicator.

THEORY

Alkalinity is the measure of the basic constituents of water and is defined the capacity

of a solution to neutralize a standard acid. In natural water it is usually present as the carbonate

and bicarbonate salts of calcium, magnesium, sodium and potassium.

Bicarbonates represent the major form of alkalinity since they are formed in

considerable amounts from the action of carbon dioxide upon basic materials in the soil. Under

certain conditions natural water may contain appreciable amount of carbon and hydroxide

alkalinity. Chemically treated water, particularly those produced in lime or lime soda ash

softening of water, contain carbonates and excess hydroxide.

Thus it is obvious that alkalinity is caused by three major classes of materials may be

ranked in order of their effect on pH as hydroxides, carbonates, bicarbonates and other salts of

weak acids.

Alkalinity is determined by titration with a standard with a standard solution of a strong

acid to certain end points as given by indicator solutions. Phenolphthalein is satisfactory

indicator for the first end point (pH approx 8.3) contributed by hydroxide and carbonate.

Methyl orange is used for the second end point (pH approx 4.5) contributed by bicarbonates.

The phenolphthalein end point of titration is defined as P alkalinity and the end point

observed by continuing the titration with same solution using methyl orange indicator is knownas total or T-alkalinity. Following table can be used for working out OH, CO3 and HCO3

alkalinity individually after completing titration.

Table


35/58

PROCEDURE

Phenolphthalein alkalinity

The 50 or 100 ml of sample in an Erlenmeyer flask, add two drops of phenolphthalein indicator

and titrate over a white tile with 0.02 N H2SO4 until the pink colour just disappears.

Total or methyl orange alkalinity

Add two drops of methyl orange indicator to the same sample in which phenolphthalein

alkalinity has been determine previously and titrate with 0.02 N H2SO4 until the colour

changes from yellow to faint orange.

OBSERVATIONS

(a) Sample .

(b) Initial pH of given sample is .

Table for phenolphthalein alkalinity

Table for methyl orange alkalinity

Result of Titration Value of radical expressed in term of Calcium Carbonate

OH- CO3-- HCO3-

P = 0

P < (T/2)P = (T/2)

P > (T/2)

P = T

0

00

2P-T

T

0

2P2P

2(T-P)

0

T

T-2P0

0

0

S.No. Volume of Sample Initial burette

reading

Final burette

Reading

Volume of

H2SO4

1.

2.

3.


36/58

CALCULATIONS

Initial pH of the sample is..

Mg/lt. phenolphthalein alkalinity as CaCO3 =

(ml. of 0.02N H2SO4 x 10 0 0 x 5 0) = ..ml. of sample

Mg/lt. of total or methyl orange alkalinity as CaCO3 =

Total ml. of 0.02 N H2SO4 x 1000 x 50 =ml. of sample.

RESULT

Methyl orange alkalinity as CaCO3 is ............mg/lt. and Phenolphthalein alkalinity is

.. mg/lt.

Total alkalinity due to bicarbonate is got by using methyl orange indicator it comes ..

. mg/lt.

CONCLUSION

Since alkalinity of tap water mg/lt. which is very large/moderate/low. Thus it can be

used/not used as drinking water because according to IS-10500:1991 range of alkalinity for

drinking water is 200-600 mg/lt. OH- ion is mainly responsible for alkalinity. Due to only OH-

ion alkalinity has range of pH 8.3 to 14 and practical range of alkalinity comes pink to colorless

solution of alkalinity above 600 mg/lt. is not good for human point of view.

SIGNIFICANCE

With in regional limit alkalinity has sanitary significance, but it is very important in connection

with coagulation, softening and corrosion preservation, Alum used in coagulation is an acid salt

which when added in small quantity to natural water, reacts with alkalinity present to form

flocs. If insufficient alkalinity is present to react with all the alum, coagulation will be

S.No.

Volume of sample Initial burette

reading

Final burette

reading

Volume of

H2SO4

1.

2.

3.


37/58

incomplete and soluble alum will be left in the water. It may therefore, be necessary to add

alkalinity in the form of soda ash or lime to complete the coagulation or to maintain sufficient

alkalinity to prevent the coagulated water fro being corrosive. Ordinarily the total alkalinity

determined with methyl orange indicator; gives sufficient information for the control of

coagulation and corrosion prevention when pH is also determined.

Many regulatory agencies prohibit the discharge of waste containing caustic alkalinity to

receiving water. Municipal authorities usually prohibit discharge of waste containing caustic

alkalinity to sewers. Alkalinity as well as pH is an important factor in determining the

amenability of waste water to biological treatment.

Lastly from public health point of view, alkaline water is usually unpalatable and consumer

tends to seek other supplies Chemically treated water some time have rather pH values, which

have met with some objections on the part of consumers. For these reasons, standards are some

times established on chemically treated water.

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

the range of6 to 9.5. This criterion often requires adjustment of pH to favorable levels and

calculations of the amount of chemical needed is based upon acidity values in most cases.

EXPERIMENT No. 4

CHLORIDE TEST

OBJECT

To determine the amount of chlorides in the given sample.

APPARATUS

Burette, Pipette and Conical flask, Silver nitrate (N/71), Potassium chromate indicator,

chemicals for pH adjustments.

THEORY


38/58

Chlorides occur in all natural water in widely varying concentrations. This chloride content

normally increases as the mineral content increases and it is usually associated with Na + ion.

The sources which contribute most of the increase of chlorides in natural water are:

(i) Due to the formation of minute salt crystals resulting from evaporation of ocean water

and then its spraying over inland areas.

(ii) Due to the solvent power of water which dissolves chlorides from top soil and deeper

formations.

(iii) Due to sea water intermixing with river water and due to over pumping that causes sea

water intrusion in group water.

(iv) Due to discharge of sewage effluents in surface water as the chloride content of urine

are about 6gms. per person per day.

(v) Due to discharge of industrial wastes in surface sources or due to seepage in ground

water.

PROCEDURE

(i) Clean the burette, pipette and conical flask with the tap water.

Adjust the pH of sample between 7.0 and 8.0.

(ii) Take 50 ml well mixed sample adjusted to pH 7.0 -8.0 and add 1.0 ml K2CrO4. Note

initial burette reading.

(iii) Titrate with standards AgNO3 solution till Ag2CrO4 starts precipitating giving red

color.

(iv) Note final burette reading.

(v) Repeat the procedure till the concurrent readings are obtained.

(vi) Determine the blank reading with the same procedure using distilled water.

OBSERVATIONS

The initial pH of the sample is ..

S. No. Volume of sample Volume of AgNO3 ( ml ) Net volume of


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AgNO3 (ml)

Initial reading Final reading

A. Tap

water

1.

2.

3.

B. Distilled

water

1.

2.

3.

SAMPLE CALCULATIONS

Initial pH is for tap water.

Mg/lt. = (A-B) x 0.5 x 1000 =ml. of sample

Where AgNO3 for sample is =

Where AgNO3 for Blank is = .

Where A = ml. of AgNO3 for sample, B = ml of AgNO3 for blank

RESULT

The chloride content of given sample is found to be mg/lt. as Cl.

CONCLUSION

In a given sample ..mg/lt chlorides present, which is Harmful / not harmful. In first

AgNo3 react with salt which has chlorides and make white precipitate and AgCl then (indicator

K2CrO4) react with AgNO3 and given brick red color. Thus at last end point comes brick red

precipitate.

SIGNIFICANCE


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Chlorides are not harmful as such but when it exceed beyond 250 mg/l it imparts a peculiar

taste to water rendering it unacceptable from aesthetic point of view for drinking purpose.

Presence of chlorides above the usual background concentration water source is also used as an

indicator for pollution by domestic sewage.

Before the development of bacteriological testing procedures, chemical tests for chloride and

for nitrogen, in its various forms, served as the basis of detecting contamination of ground

water by sewage. Chlorides are used to some extent as tracers in sanitary engineering practices.

Where brackish water has to be used for domestic purposes, the amount of chlorides present in

the source is an important factor in determining 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.

EXPERIMENT No. 5

HARDNESS TEST

OBJECT

To determine the total hardness and calcium hardness of a given sample of water.

APPARATUS

Burette, Pipette, Conical flask, etc.

REAGENTS

Standard EDTA solution (N/50), Ammonia buffer solution and NaOH solution, Eriochrome

black T indicator and Murex indicator (dry power), inhibitor.

THEORY

Water that consumes considerable quantity of soap to produce lather and or produces scale in

hot-water pipes, heater, boilers and utensils used for cooking is called hard water.

Harness is caused by divalent metallic anions that are capable of reacting with soap to form

precipitates with cations present in water to form scale. Principal actions causing hardness and

the major anions associated with them are as listed below:

CATIONS ANIONS

Ca++ HCO3-

Mg++ SO4--

Sr++ Cl-

Fe++ NO3-Mn++ SiO3--


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Calcium and magnesium are primarily the constituents of chalk and limestone. When rain falls

it takes up carbon dioxide from the atmosphere and forms a weak acid and this percolates

underground, it then dissolves calcium and magnesium forming hard water. IN general hard

water originates in the areas where the topsoil is thick and limestone formations are present.

Soft water originates in areas where the topsoil is thin and limestone is either sparse or absent.

The scale of hardness from consumers point of view may be taken as below:

Hardness may be classified as:

(a) Carbonate and non carbonate hardness

(b) Calcium and magnesium hardness, and

(c) Temporary and permanent hardness.

PRINCIPLE

In alkaline condition EDTA (Ethylene-diamine tetra acetic acid) or its sodium salt forms a

soluble chelated complex, which is stable with Ca and Mg. Also Ca and Mg form a weak

complex with the indicator Eriochrome black T, which has wine red color. During titration

when all free hardness ions are complexed by Eriochrom black T indicator end point. The pH

has to maintain at 10+0.1.

At higher pH i.e. about 12.0 mg ion precipitates and only Ca++ ions remain in solution. At this

pH murex indicator from a pink colour with Ca++, gets complexed resulting in a change frompink to purple, which indicates and point of the reaction.

INTERFERENCE

Metal ions do interfere but can overcome by addition of inhibitors.

0

50

100

150

Over

50 ppm

100ppm

150ppm

250 ppm

250 ppm

Soft

Moderately soft

Slightly hard

Moderately hard

Hard


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PROCEDURE

A. TOTAL HARDNESS

1. Rinse burette, pipette, and flask, etc.

2. Take 25 or 50 ml of well-mixed sample in a flask.

3. Add 1-2 ml buffer solution followed by 1 ml inhibitor.

4. Add a pinch of Eriochrome black T and titrate with standard EDTA solution till

wine red colour changes to blue. Note down the volume of EDTA required.

B. CALCIUM HARDNESS

1. Take 25 ml of sample in a flask.

2. Add 2-3 drops of NaOH (N/10) to raise pH to 12 and a pinch of indicator. Note

initial burette readings.

3. Titrate with EDTA till pink colour changes to purple . Note the final burette

readings.

4. Repeat the procedure for other sample s till concurrent readings are obtained.

C. MAGNESIUM HARDNESS

1. Take 100 ml of sample , add 1.5 ml of the buffer solution and 2.3 ml of a

saturated solution of ammonia oxalate.

2. Mix the solution and allow it to stand for two hours or overnight if possible.

3. Filter , using a No. 42 Watman filter paper.

4. Pipette out 25 ml from the filtered solution and add Eriochrome black tT

indicator (1-2 drops) and titrate with EDTA solution till the colour changes from

wine red to blue.

5. Take two concurrent readings.

OBSERVATIONS FOR TOTAL HARDNESS

S.No. Volume of sample Initial

reading

Final

reading

Net volume

of EDTA

(ml)

Total

hardness

mg/lt. as

CaCO3

1.

2.

3.

4.

OBSERVATIONS FOR CALCIUM HARNDNESS


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S.No. Volume of sample Initial

reading

Final

reading

Net volume

of EDTA

(ml)

Calcium

hardness

mg/lt.

1.

2.3.

4.

SAMPLE CALCULATIONS

(a) Total harndness:

Total hardness (mg/litre) = ml. of EDTA x 1 x 1000

ml. of sample

(b) Calcium harndness :

Calcium hardness (mg/litre) = ml. of EDTA x 1 x 1000

ml. of sample

(c) Magnesium harndness:

Magnesium hardness (mg/litre) = Total hardness - Ca

RESULT

For the given tap water sample the hardness is found to be mg/lt., Calcium hardness is

. mg/lt. and Magnesium hardness is mg/lt.

CONCLUSION

As the total hardness and calcium hardness are below/above the maximum tolerable value i.e.

600 and 200 respectively. The water can be used/not used for domestic purposes.

SIGNIFICANCE

The determination of hardness is helpful in deciding the suitability of water for domestic and

industrial purpose. The design of softening process depends upon the relative amounts of

carbonate and non-carbonate hardness present in water. The amount of calcium and

magnesium hardness decides the suitability of water for boiler use.

EXPERIMENT No. 10

DETERMINATION OF AVAILABLE CHLORINE FROM BLEACHING POWDER

CaOCl2 AND RESIDUALCHLORINE IN THE GIVEN SAMPLE OF WATER


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OBJECT

1. To determine the available chlorine in bleaching powder.

2. To determine the residual chlorine in given sample of water.

APPARATUS

Burette, Pipette, Conical flask, Stirrer.

REAGENTS

KI solution, Glacial acetic acid, Distilled water, Starch, Sodium thiosulphate solution.

THEORYIn small water works, chlorine required for disinfections is usually obtained

from bleaching powder. For this purpose iodometric method i.e. oxidation-reducation

method is employed. The iodometric method is more precise when the residual chlorine

concentration is greater than one ppm . Chlorine will liberate free iodine from KI

solution when its pH is 8 or less. The liberated iodine is titrated against standard

solution of sodium thiosulphate using starch as indicator. When blue colour disappears

then all the liberated iodine will have reacted. This indicates the end point.

PROCEDURE

1.5 gram of bleaching powder is taken and dissolved in 1 liter of distilled water.

The solution thus prepared is to be tested for available chlorine. 20 ml. of 10% KI is

taken in a clean, dry conical flask, 2 ml of glacial acetic acid is added into the flask to

reduce pH 3 to 4.12. 12 5 ml of bleaching powder solution is then pipetted out and is

added in the flask. The colour of the solution will be brown. Tritrate this solution


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against N/40 sodium thiosulphate solution, till pale or straw yellow colour is developed.

At this stage, add 2 drops of freshly prepared starch solution, which results in

appearance of blue colour. The titration against sodium thiosulphate solution is

continued till the blue colour disappears. This indicates the end point. Initial reading

and final reading of sodium thiosulphate solution in the burette is noted, the difference

is then found out. The whole experiment is repeated and the mean difference is taken.

OBSERVATIONS

S. No. Burette Reading Mean

difference

Initial Final Difference

1.

2.

3.

CALCULATIONS

Quantity of chlorine in = Number of ml. of thiosulphate solution of

mg/lt. in the water sample N/40 normality remove the blue colour

Chlorine of given sample = N (Na2S2O3) X Volume of Na2S2O3

= mg/lt. as chlorine

Quantity of chlorine in mg/lt. in the sample = .(ml.of sodium thiosulphate as

required)

CHLORINATION

Chlorine is widely used for disinfection of water for removing odour since it is a

powerful oxidizing agent and is cheaply available. It can be used in molecular from or

in hypochlorite form. For effective disinfection, does of chlorine, optimum contact

period and residual chlorine are required to be found out.

PRINCIPLE


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Chlorine combines with water to form hypochlorous and hydrochloric acid.

Hypochlorous acid dissociates to give OCl- ion. Quantities of OCl- and HOCL- depend

on pH of the solution. Hypochloricdes also gives the OCl- ions, HOCl- rupture the cell

membrane of microbes, the disease producing organisms. These also reacts with the

impurities like ammonia, oxidisable inorganic matter like ferrous ion, nitrites etc. to

from chloramines and stable ions of the latter respectively.

INTERFERENCE

Oxidisable organic and inorganic matter.

REAGENTS

1. Bleaching powder

2. Concentrated acetic acid

3. Potassium iodide crystals

4. Standard sodium thiosulphate 0.1 N-- Dissolve 25g Na2S2O3.5 H2O and dilute to

1000ml in freshly boiled and cooled distilled water. Add about 5ml chloroform

asa preservative.

5. Starch indicator: Prepare slurry by adding small quantity of water to 1g starch

powder. Add it to 100ml boiling water and continue boiling for few minutes

then

cool and uses.

6. Standard chlorine solution : Procedure outlined under analysis of bleaching

powder.

REACTION

When chlorine is added to water it forms hypochlorous acid or hypochlorine ions.

Cl2 + H2O pH > 5 HOCl + HCl

Hypochlorus acid is unstable and may break into hydrogen ions & hypochlorite ions.

HOCl pH > 8 H+ + OCl-

pH < 7


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More over the chlorine will immediately react with ammonia present in water to from

various chloramines.

NH3 + HOCl NH2 Cl2 + H2O

PROCEDURE

1. Take 1000ml sample in 12 stoppered bottles.

2. Add standardized chlorine solution in ascending order. If chlorine demand of treated

water is being estimated, doses from 0 to 300mg Cl2/l. 1 will be found useful.

However, if the sample is polluted, doses from 0.1 mg to 3 mg Cl2/l may be required as

in case of treated effluents etc.

3. Allow a contact period of 30 minutes of probable water and suitably higher for pollutedwater, or secondary effluents.

4. Estimate residual chlorine iodometrically as described under analysis of "bleaching

powder"

5. Plot residual chlorine versus chlorine added. In case of organically polluted samples, a

distinct break point can be obtained. But in case of treated water sample, it is possible

that only a straight line is obtained in absence of any ammonium. A residual 0.2 mg

Cl2/lt. after the break point is recommended.

CONCLUSION

We have found the result in the above test is . mg/lt. chlorine that chlorine is

satisfied / not satisfied as compare to permissible limit. The permissible limit is 0.2

according to IS: 10500, hence given sample of water does not required to drinking

purpose. The amount of available chlorine in a sample indicates that bacteria are

reduced up to safer limits but when it increases above the permissible limit. It may lead

to the water born disease. In this water sample the chlorine is below / average / above/

as per permissible limit. So it is fit / not fit for drinking and can be accepted / rejected.

RESULT

The amount of available chlorine in given sample of water is mg/lt. as

chlorine.


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SIGNIFICANCE

If the amount of available chlorine present in water is more to the permissible

limit than the water should be unpleasant taste characteristics. But if it present within

limit forms hydrochlorous acid and killed the bacteria present in the water as it has been

described earlier.


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EXPERIMENT No.11

BREAK POINT CHLORINATION

OBJECT

To determine the break point chloride demand of given sample of water.

APPARATUS

A number of bottles with stoppers, pipette, O.T. test comparator, stock solution of Cl2 of known strength.

THEORY

The determination of break point chlorine demand of water is in effect the extension of experiment

already performed for determination of chlorine demand of water. As discussed already in the said

experiment the residual chlorine appears only after the demand has been met after adding a particular

dose of chlorine, at definite period of contact.

In the absence of ammonia or its derivatives in water, the residual chlorine is the free available chlorine

in the form of HOCL and/or OCI which are oxidants and react with orthotolidine to show residual

chlorine. Thus once the residual appears, it will go on increasing with increase in applied dose.

However, when ammonia is present, the hypochlorus acid i.e. HOCL reacts with it form chlorine's first

mono and then dichlormine if excess of HOCL is available

HOCl+NH3 = NH2Cl+H2O

and HOCl+NH3Cl = NHCl2+H2O

Both dichloromine and monochloromine are oxidizing agents as if HOCL and react with orthotolidine to

show residual chlorine. Hence, in the presence of ammonia in water, the residual chlorine is the sum

total of the action of HOCL and chloromines is called the "Combined available chlorine" and the total

residual of chloride is both due to free and combined available chlorine.

An interesting stage comes in when all the ammonia present has been converted into monochloromine

with addition of Cl2. At this stage further addition of chlorine will not results in increase of residualbecause of the following reaction:

NHCl2+HOCl =NCl3+H2O

The conversion of NHCl2 to NCl3 rather results in drop of residual chlorine from the level already

attained. This is due to the fact that NCl3 is non-oxidizing and does not react with O.T. and thus the drop

in NHCl2 results in drop of residual chlorine with added does of chlorine. Thus once against the chlorine

demand goes on increasing because of consumption of chlorine in producing NCl3, which does not

show any residual. A stage reaches when all the NCHCl2 present is converted into NCl3 and there is no

combined available chloride at all, the chlorine demand is maximum at this product. This is called the

break point" in chlorination. Further addition of Cl2 will again show residual but this will be in the from of

free chlorine i.e. HOCl and OCI as all the NH3 has been converted into NCl3 or oxidized to free nitrogen


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CALCULATIONS

CONCLUSION AND RESULT

SIGNIFICANCE

Sample

No.

ml of Cl2 Solution

added

Dose of Cl2 in

ppm

Residual chlorine after

10 minutes

1 2 3 4 5


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EXPERIMENT NO. 17

CHEMICAL OXYGEN DEMOND

OBJECT

To determine the chemical oxygen demand of a given sample of sewage.

APPARATUS

Pipette, Burette, Conical flasks, Condenser, Hot plate.

REAGENTS

K2Cr2O7 solution, Conc. H2SO4 , Ferrous ammonium sulphate, Ferrous indicator, distilled water

etc.

THEORY

Chemical Oxygen Demand (C.O.D.) is also referred to as the Dichromate

oxygen consumed. The C.O.D. test is quick method of estimating the

approximate amount of organic matter in sewage and industrial wastes. In

C.O.D. determination, the organic matter is oxidized by dichromate in the

presence of sulphuric acid. A catalyst such as Silver sulphate is used to help the

oxidation of the organic matter. The excess of dichromate is liberated by ferrous

ammonium sulphate solution. It may be noted that C.O.D. values are not

directly correlated with B.O.D. values.

PROCEDURE

Take 50 ml of the sample on an aliquot diluted to 50 ml in a 300 ml round bottom flask with

ground glass neck and fitted with a Friedriche reflux condenser. The amount of sample taken

should have a C.O.D. less than 1,000 mg/ liter. Add 25 ml of 0.25 N K2Cr207 solution, and 7.5

ml of conc. H2SO4 .The acid should be added in small amounts carefully mixing after each

addition. Add a few glass beads or pumice granules to the mixture to avoid bumping. Attach

the flask to the condenser and reflux for 2 hours. For some industrial wastes, a shorter period of

refluxing is sufficient. Cool and wash down the reflux condenser with 25 ml of distilled water.

Transfer the content to a 500 ml. Erlenmeyer flask rinsing 4 or 5 times with distilled water.

Dilute the mixture to about 350 ml with distilled water. Titrate with Ferrous ammonium

sulphate solution using 2 to 3 drops of ferrous indicator. The colour change is from blush-green

to reddish blue at the end point.


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Carry out a blank determination using 50ml distilled water and the same volume of reagents.

It may be necessary to used silver sulphate as catalyst for the complete oxidation of many

organic compounds such as straight chain acids and alcohols. In such case, 1gm of Ag2SO4

crystals should be added directly to the mixture before refluxing.

CALCULATION

mg /lt. of C.O.D. = (X Y) x Normality of FeSO4 (NH4)2SO4 x 8000

ml.of sample

Where , C.O.D. = Oxygen consumed from K2Cr2O7

X = ml. of FeSO4 (NH4)2 SO4

Y = ml. of FeSO4 (NH4)2 SO4

When Silver sulphate is not used, the chloride contents of the sample have to be determined

and correction applied as follows:

Chloride correction = mg / liter chloride x 0.23

REACTION

Conc. H2SO4Organic Matter + K2Cr207 ------------> CO2 + H20

OBSERVATION


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RESULTS

The C.O.D. of given sample is found to be mg/l as O2.

CONCLUSION

SIGNIFICANCE

This test is a measure of oxygen present in organic matter in sewage. It is useful in

identifying the performance of various steps of treatment plants. It is also useful in

determining the strength of industrial waste in sewage which can't be determined by

B.O.D. test. This test has advantage of being fast & less time consuming.

S.No. Sample Volume of Sample F.B.R. Vol. of

SO4

FeSO4 (NH4)2

1. Blank

2. Sample


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EXPERIMENT No.18

BIOCHEMICAL OXYGEN DEMAND

OBJECT

To determine the biochemical oxygen demand of the given sample of sewage.

APPARATUS

B.O.D. incubator, Burette, Pipette, and Flasks.

REAGENTS

Manganese sulphate solution, Alkaline azide iodide solution, Concentrated sulphuric acid, N/40

Sodium thiosulphate, starch solution, FeCl3, MgSO4, CaCl2, Na2CO3 and Phosphate buffer.

THEORY

The biochemical oxygen demand may be defined as the amount of oxygen

required by bacteria to stabilize organic matter under aerobic condition. The

B.O.D. test is widely used to determine the pollution strength of the sewage,

industrial waste etc. It is a test of prime importance in the evaluation of the

purifying capacity of receiving bodies of water. It is a device test. It involves the

measurement of the dissolved oxygen contents of a sample before and after a

bioassay process in which living organism serve as a medium for the oxidation

of organic matter to carbon-dioxide and water. It therefore is possible to

interpret B.O.D. in terms of organic matter as well as the amount of oxygenused during its oxidation, under atmospheric conditions. Nitrogen is nearly

twice as soluble in water as in oxygen. Most of the critical conditions related to

dissolved oxygen deficiency in Sanitary Engineering practice occur in periods

of high temperature.

The kinetics of B.O.D. reaction indicate that they are first order reaction, in

which the rate of the reaction is proportional to the amount if oxidisable organic

matter remaining at any time as modified by population of active organisms.


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This can be expressed in the form of an equations, thus Y = L (1 - 10 -kt) , where

Y = B.O.D. at any time and Y = (I 10-kt).

Experiments have shown that a reasonably large % (68 -70) of the B.O.D. is

exerted in the first five days incubation. The test is, therefore, carri

Lab Manual on Water and Waste Water Analysis by Santosh Kumar Kharole

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