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1. Environmental Engineering- I
By
Akash Padole
Department of Civil Engineering
Quality of Water

2. Need of Analysis of water
• Free from pathogenic organisms
• Clear
• Not saline
• Free from offensive taste or smell
• Free from compounds that may have adverse effect
on human health
• Free from chemicals that cause corrosion of water
supply systems
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3. Important requirements of water for domestic use:
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4. Techniques of Sampling
Grab Sampling
• A single sample of water collected from sampling
spot at any instant
Composite Sampling
• Mixture of grab samples at same point for different
time
• Interval is 30min /60min/120minutes for 24 hrs.
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5. Water Quality Parameters
1. Physical parameters
2. Chemical parameters
3. Bacteriological parameters
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6. Physical parameters
• Colour
• Taste and Odour
• Temperature
• Suspended Solids
• Turbidity
• Conductivity
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7. IS: 10500-2012
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8. Colour
• May be due to the presence of organic matter,
metals (iron, manganese) or highly colored industrial
waste
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9. • Aesthetically displeasing
• Psychological point of view
• Desirable that drinking water be colorless
• Certain colour causing organic compounds react with
chlorine to form carcinogenic
• Acceptable limit, 5 Hazen unit
• Permissible limit 25 Hazen Unit
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10. • Measurement: Tintometer
• It can also be measured by comparing the color of
water sample with other standard glass tube called
“Nessler’s Tube”.
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11. Taste and Odour
• Mainly due to organic substances, Biological activity,
industrial pollution.
• Taste buds in the oral cavity specially detect
inorganic compounds of metals like magnesium,
calcium, sodium, copper, iron and zinc
• Water should be free from objectionable taste and
odour.
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12. • Taste & odour due to:
– presence of dissolved gases like H2S, CH4, CO2, O2
etc.
– Dissolved organic matter like algae
– Mineral salts like NaCl, iron compounds,
chemicals, industrial waste
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13. • An instrument use for odour test is called Osmoscope.
• Odour is measured by in terms of Threshold Number.
• The minimum odour that can be detected is called
Threshold Odour Number (TON)
• Permissible value: 1 to 3 TON.
TON =
𝐴+𝐵
𝐴
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14. Pure Water
40 ml
40 ml
T & O
80 ml 40 ml
120 ml
Pure Water
40 ml
160 ml
Pure Water
40 ml
200 ml
Unobjectionable
taste and odour
TON=
𝐹𝑖𝑛𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒
𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒
=
200
40
= 5 TON
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15. Temperature
• Temperature of water has no practical significance
however temp of water should be above 10°C while
temperature above 25°C are considered as
objectionable.
• Affects the oxygen holding capacity
• Increase of temperature increases the biological
activities.
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16. Suspended Solids
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17. • Suspended Solids derived from
– Inorganic Particles like clay, silts, sand, glass, etc. or
Organic Particles like plants, algae, planktons, etc.
• Capable of causing diseases
• Reduces the discharge caring capacity.
• Makes the water aesthetically displeasing, hence
induce psychological effects.
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18. W1
W2
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19. Akash Padole 19

20. • Acceptable limit: 500 mg/l
• Permissible limit: 2000 mg/l
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21. Turbidity
• Resistance offered by the passage of light
• Caused by suspended matter.
• If turbidity is more than 5 mg/l  Naked eyes
Nephelometer Turbidimeter
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22. • Measured in Nephelometric Turbidity Units (NTU)
• Estimates light scattering by suspended particles
• Photocell set at 90o to the direction of light beam to
estimate scattered rather than absorbed light
• Good correlation with concentration of particles in
water
• Turbidity in natural water interferes with the
perpetration of light thereby retards the
photosynthesis process.
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23. • Acceptable limit: 1 NTU
• Permissible limit: 5 NTU
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24. Measurement of Turbidity
1. Turbidity Rod Method
2. Jackson’s Turbidimeter Method
3. Bayli’s Turbidimeter
4. Nephlometer
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25. Turbidity Rod Method
• It is a field method that consist of aluminum rod having
platinum needle at its tip having size of 1mm and 25mm
long.
• This rod is immersed in the sample to be tested and
depth at winch platinum needle ceased to be seen is
noted that is further calibrated to gives the turbidity.
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26. Akash Padole 26

27. • It is expressed in terms of standard unit which is
obtained by the addition of silica as SiO2 (Fuller’s
Earth) in powdered form in 1 lit of pure water.
• It is expressed as STU (Silica Turbidity Unit), mg/l,
ppm.
• Turbidity more than 5 STU can be easily detected by
naked eyes.
• More length --> lesser the turbidity
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28. Jackson’s Turbidimeter Method
• It is a lab method that gives the turbidity if it is
greater then 25 units. Hence mostly used for muddy
water and not for drinking water.
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30. • The principal used in both the above tests is same
i.e., longer is the length of path travelled by the light,
smaller is the turbidity and vice versa.
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31. Bayli’s Turbidimeter
Known Standard sample
Sample
Used to measure 0 to 10 mg/l
Works on principal of color matching technique
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32. Nephlometer
• Modern turbidimeter
• Based on the Principle of scattering of light
• Formazine polymer is used in place of silica in 1 lit of
water
• It is represented as FTU (Formazine Turbidity Unit) or
NTU (Nephlometric Turbidity Unit)
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33. Conductivity
• Total amount of dissolved salts present in water can
se easily estimated by measuring the specific
conductivity of water.
• It is measured by di-ionic tester which gives the
concentration of common ions like Na, Ca, Mg, CO3,
Cl, SO4.
• The specific Conductivity of water is in micro mho
per cm at 25oC is multiplied by a coeff. (0.65) so as to
directly obtained the dissolved salt contain in ppm.
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34. Chemical parameters
pH
Alkalinity
Hardness
Chloride
Nitrogen
Fluoride
Metals
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35. pH
• pH is a measure of the acidic or basic characteristics of
water
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36. • It is the measure of hydrogen ion concentration.
pH = -log10 [H+]
• So a pH of 7 means the [H+]=10-7
• Neutral water pH---> 7
• Acidic water has pH below 7
• Basic water has pH above 7
• pH for exact neutrality, however, varies with
temperature from 7.47 at 0°C
through 7.0 at 25° C
to 6.765 at 40° C.
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37. Alkalinity
• Alkalinity of water is its quantitative capacity to
neutralize a strong acid to a designated pH.
• The possibility to maintain constant pH is due to the
hydroxyl, carbonate and bicarbonate ions present in
water.
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38. Akash Padole 38

39. • Alkalinity is significant in many uses and in treatment
of water and wastewater.
• It is significant in determining suitability of water for
drinking as well as irrigation purpose.
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40.  NH3 Ammonia
 HSiO3 Hydrogen Silicate Ion
 H2BO3 Dihydrogen Borate
 H2PO4 Dihydrogen Phosphate
 HS Hydrogen Sulphide
Major Constituents
Minor Constituents
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41. Standards of Alkalinity recommended for drinking:
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42. Akash Padole 42

43. • When P=0, that means we use the phenolphthalein indicator and
both the ions will get neutralized.
• Hence, OH and CO3 ions will be absent in the water sample.
• So, the alkalinity is only due to HCO3
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46. Q: Which ions are responsible for Alkalinity
of a given sample?
Example
o Vol of water sample = 50 ml
o Vol of Acid when phenolphthalein indicator is used = 20 ml
o Vol of Acid when methyl orange indicator is used = 15 ml
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47. Hardness
• “Hard waters” are generally considered to be those
waters that require considerable amounts of soap to
produce foam and that also produce scale in water
pipes, heaters, boilers and other units in which the
temperature of water is increased.
• Property of water by which it does not produce lather
with soap.
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48. Hard Water
Soft Water
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49. Akash Padole 49

50. • “Hardness” is a property of water which represents total
concentration of Ca & Mg ions in CaCO3.
• “Concentration of the multivalent cations present in
water is termed as Hardness”
• Multivalent metallic cations in solution including:
Calcium (Ca+2), Magnesium (Mg+2), Potassium (K+),
Sodium (Na+), Aluminium (Al3+), Iron (Fe2+) Manganese
(Mn2+) and Strontium (Sr2+)
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51. • There are two forms of hardness,
1. Carbonate or temporary hardness associated with
carbonates and bicarbonates of calcium and
magnesium and
2. Non-carbonate or permanent hardness associated
with sulphates(SO4), chlorides(Cl) and Nitrate(NO3)
of calcium and magnesium.
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52.  Al Aluminum
 Sr Strontium
 Fe Iron
 Cu Copper
 Mn Manganese
Major Constituents
Minor Constituents
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54. Akash Padole 54

55. Standards of Total Hardness recommended for drinking:
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57. Akash Padole 57

58. HARDNESS = 𝐶𝑎2 + 50
20
+ 𝑀𝑔2 + 50
12
(Eq. Wt.)
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59. Akash Padole 59

60. Classification of Hardness Types
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61. Chloride (Cl-)
• Chlorides are widely distributed as salts of calcium,
sodium and potassium in water and wastewater.
• In potable water, the salty taste produced by chloride
concentrations is variable and dependent on the
chemical composition of water.
• The major taste producing salts in water are sodium
chloride (NaCl) and calcium chloride. (CaCl2)
• The salty taste is due to chloride anions and
associated cations in water.
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62. Environmental Significance
• The high concentrations of chloride ions mostly
results in an unpleasant salty taste of water and it
also aides the corrosion of plumbing system.
• Very high chloride content of water may also
produce laxative effect. (laxatives can
cause diarrhea or intestinal obstruction)
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63. • An increase in the normal chloride content of your
water may indicate possible pollution from human
sewage, animal manure or industrial wastes.
• As all aware the sea water is full of sodium chloride,
the chloride levels will be much higher compared to
the fresh water sources.
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64. IS: 10500 - 2012
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65. Nitrogen Content
(Nitrogen Compounds)
• The presence of nitrogen in water is an indication of
the presence of the organic matter and may occur in
one or more of the following forms:
• Free Ammonia
• Organic Ammonia or Albuminoid
• Nitrites
• Nitrates
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66. • Free Ammonia indicates the very first stage of
decomposition of organic matter (thus indicating
recent pollution).
• Albuminoid nitrogen or Organic Ammonia indicates
the presence of nitrogen in water before the
decomposition of organic matter.
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67. • Organic Ammonia can be measured by adding strong
alkaline solution of KMnO4 to already boiled water
sample and again boiling the same.
• Ammonia gas thus liberated is measured which gives the
quantity of organic nitrogen.
• The sum total of Free Ammonia and Organic Ammonia is
called Kjedahl Nitrogen.
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68. • Nitrites (NO-
2) indicates the partial decomposition of
organic matter, thus indicating the progress of
treatment and its highly dangerous.
• Nitrates (NO-
3) indicates the presence of fully
oxidized or complete decomposition organic matter
in water.
• The presence of nitrates indicates the well oxidized
and treated water.
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69. • Presence of nitrate is not harmful.
• But higher quantity of nitrates adversely the health
of infants, causing a disease called
MATHEMOGLOBINEMIA (commonly called as blue
baby disease)
• The process of conversion of ammonia into nitrate is
referred as NITRIFICATION
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70. Akash Padole 70

71. Nitrogen Compounds Acceptable limit (mg/l)
Free Ammonia 0.15
Organic Ammonia or Albuminoid 0.30
Nitrites 0
Nitrates 45
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72. FLUORIDE CONTENT
• Up to 1 mg/l of fluoride is required to prevent dental
cavities and to allow the growth of permanent teeth.
• If the fluoride concentration is more then 1.5mg/l, it
causes de-colourization and mottling of teeth
resulting in the disease termed as FLOURISIS.
• If it is more than 5 mg/l, it causes deformation of
bones and results in the diseases termed as BONE
FLOURISIS.
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73. IS: 10500 - 2012
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74. Metals
Metals in water are either toxic or non toxic.
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75. 1. Sodium:
– Presence of sodium makes the food tasteless and affects
the heart and kidney.
– It makes the metal surface corrosion
– Presence of sodium is determined by ATOMIC
ABSORPTION SPECTROMETRY.
– Limit: 50 to 250mg/l
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76. 2. Iron and Manganese:
– Iron and Manganese in water causes the colour problem if
the concentration is more than 0.3 mg/l and 0.45 mg/l
respectively.
– Certain type of micro organisms utilizes there metals and
used as a source of energy. Hence they are capable of
forming the diseases.
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77. IS: 10500 - 2012
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78. 3. Copper:
– Presence of copper in high concentration affects the lungs
and respiratory organs.
– CuSO4 if more than 250mg/l induces laxative effect.
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80. Different types of gases
• H2S:
– Gives rotten egg smell.
– Its presence indicates presence of organic matter
• CH4:
– Methane is known for explosive tendency
– Its presence indicates biological activity in water
• CO2:
– Its presence adds bad taste in water and makes the pipe
corrosive
– It indicates Biological Decomposition of organic matter.
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81. • O2:
– At any temperature, max oxygen that may be present in
water is termed as saturation Dissolved oxygen
– Any deficiency in O2 indicates biological activity in water
– Min. 4ppm of O2 is required for survival of aquatic life
– This is calculated using titration method.
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82. Bacteriological parameters
• Most of the organic matter present in water is
unstable and decomposes readily through chemical
as well as the biological processes.
• The organic matter which can be decomposed by
bacteria under biological action, is called
biodegradable organic matter.
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83. • Most of the organic matter present in water is
biodegradable and hence undergo biological
decomposition, which can be divided into
i. Aerobic decomposition
ii. Anaerobic decomposition
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84. Aerobic decomposition
• Aerobic decomposition is caused by both aerobic
bacteria operating aerobically, in presence of air or
oxygen which is available in the waste water in the
dissolved form.
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85. Anaerobic decomposition
• If free dissolved oxygen is not available to the water
or sewage, then the anaerobic decomposition, called
putrefaction will occur.
• Anaerobic bacteria operating anaerobically, will then
flourish and convert the complex organic matter into
simpler organic compounds of nitrogen, carbon, and
Sulphur.
• These anaerobic bacteria survive by extracting and
consuming like nitrate and sulphates.
• Gases like ammonia, hydrogen sulphide, methane
etc. are also evolved in this decomposition,
producing obnoxious (bad) odour.
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86. Facultative Micro organisms:
– There are certain types of micro organisms which
can act both presence or absence of oxygen, these
micro organisms are referred Facultative micro
organisms.
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87. • Pathogens:
– The most important micro organisms present in
water that are capable of causing the diseases are
termed as Pathogens.
– Testing and counting of pathogens can be done
but with the great difficulty and the test involved
are very costly.
– Hence instead of testing for pathogens, it is being
tested for Coliforms which are harmless micro
organisms.
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88. – But there presence and absence indicates the
presence and absence of pathogens.
– Coliforms are of two types
i. E-Coli
ii. B-Coli
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89. • Testing and counting of pathogens in Lab
1. Membrane Filter Technique
2. MPN
3. Coilform Index Test
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90. Sterile Membrane
Incubator T= 35oC
Time = 20-22 hr
M-Endo medium
TYPE OF NUTRIENT
(Provide the growth
of coliform bacteria)
Count the no of coliform’s colony
1. Membrane Filter Technique
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91. MPN
• A series of lactose-broth (type of nutrient used to
grow the coliform) tubes are inoculated with
measured amounts of the water sample to be tested.
• The series of tubes may consist of three or four
groups of three, five or more tubes.
• The more tubes utilized, the more sensitive the test.
• Gas production in any one of the tubes is
presumptive evidence of the presence of coliforms.
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92. MPN
Presumptive
test
Confirmatory
test
Completed
test
Presence of coliform bacteria
Conforms it Test in which MPN is find out
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93. 10ml
Raw water sample
9 ml
Pure
water
1ml
9 ml
Pure
water
1ml
9 ml
Pure
water
1ml
1ml
Dilution
0.1ml
Dilution
0.01ml
Dilution
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94. 5 test tube of 10ml
5 test tube of 1ml
5 test tube of 1ml
Lactose Broth
Incubate at
35oC for 48hr
Gas is formed then positive test
Green bile broth
Incubate at 35oC
for 24-48hr
Gas is formed
Conformed that
coliform is present
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95. 10 ml 1 ml 0.1 ml
Total test tubes 5 5 5
Positive tests 2 0 1
7 coliforms is
present in 100ml of
sample
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96. 1 ml 0.1 ml 0.01 ml
Total test tubes 5 5 5
Positive tests 2 0 1
70 coliforms is
present in 100ml of
sample
7 x 10
= 70
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97. Akash Padole 97

98. Example
3 1
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99. RESULT
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100. Akash Padole 100

101. • Most Probable Number represents “the microbial
density which are most likely to be present in the
water sample.”
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102. Akash Padole 102

103. Eutrophication
• It is a process in which water body get infested
with algae and gradually silt up to become
shallower due to entry of nutrients (C, N, P)
into a water body.
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104. Akash Padole 104

105. Agriculture
Runoff/ untreated
sewage
Aquatic ecosystem
(Nutrients
increases)
Algae increases
(Algal bloom)
Restriction of
Sunlight
Underground
Algae, plants die
Oxygen demand
increases
Fishes Die
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106. Algal bloom
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107. Akash Padole 107

108.  Reason of Eutrophication:
1. Natural
i. Soil erosion
2. Anthropogenic Activities
i. Deforestation
ii. Agricultural
iii. Industries
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