Btech 1st year water technology

1. Applied Chemistry
[1st and 2nd Semester, First Year]
1st semester: Computer Science Engg.
Electrical Engg.
Electronics & Telecom Engg.
Information Technology Engg.
Mechanical Engg.
Metallurgy & Material Sc.
Department of Chemistry
NIT Raipur

2. Course Content [For 3 Credits]
• Unit – I : Technology of Water
• Unit – II : Fuels, Combustion & Cement
• Unit – III : Corrosion and Phase Rule
• Unit – IV : Lubricants & Polymers

4. Unit-I: Technology of Water
• Standards for drinking water
• Methods of Treatment of water for domestic and industrial
purposes: sedimentation, coagulation, filtration, sterilization,
break point chlorination.
• Determination of alkalinity and hardness of water.
• Demineralization of water, softening of water: lime-soda
process, ion-exchange process, zeolite process.
• Boiler Troubles: Carry Over, Priming, Foaming, Scale,
Sludge, Corrosion, Caustic Embrittlement.
• Internal treatment of water: Carbonate conditioning, Phosphate
conditioning, Colloidal conditioning, Calgon conditioning.
• Calculations on water softening by Lime-soda process, Zeolite
process.

5. Introduction
• Water is very crucial for existence of all living
being( humans, animals and plants).
• Nearly,80% of earth’s surface is contributed by
water.
• But only 1% of the world’s water resources are
available for ready use.
• Various types of impurities are present in
water. Which spoil the colour, odour and taste
of water and make it turbid.

6. Impurities in water
Suspended impurities : When large suspended
particles of clay, sand, silt or vegetation between 1 –
10µm are found in water.
They cause turbidity, colour & odour to water.
 Colloidal impurities : Colloidal particles are
much smaller than suspended particles, at just 0.01 –
1.0µm like organic waste, finally divided silica & clay
etc.
They regularly interfere with analytical techniques, and
bypass ion exchange resins, which result in lower
resistivity in DI water.

7. Dissolved impurities :
• Inorganic ions: Silicates, chlorides, calcium, fluorides,
magnesium, phosphates, bicarbonates, sulphates, nitrates
and ferrous compounds.
The instability in water caused by these ions will negatively
influence chemical and biological reactions.
• Organic ions: These are derived from animal and plant
decay, in addition to any human activities that involve the
introduction of alcohol, protein, pesticides, chloramine,
herbicides or detergents into the environment.
• Dissolved gases: Water contains naturally dissolved carbon
dioxide, nitrogen and oxygen, but these gases can alter the
pH of water, which upsets the ionic balance.

8. Microorganisms:
• They include Bacteria, algae fungi
and protozoans.
• These bacteriological impurities make water
dangerous for human consumption.
• These may cause water born diseases e.g.
typhoid, dysentery, meningitis, polio,
hepatitis.
Water can be amenable for domestic,
potable and industrial applications only
after purifications.

9. Water Quality Parameters
No.
Types of water quality parameters
Physical parameters Chemical parameters
Biological
parameters
1 Turbidity pH Bacteria
2 Temperature Acidity Algae
3 Color Alkalinity Viruses
4 Taste and odor Chloride Protozoa
5 Solids Chlorine residual
6
Electrical conductivity
(EC)
Sulfate
7 Metal ions
8 Hardness
9 Dissolved oxygen
10
Biochemical oxygen demand
(BOD)
11 Chemical oxygen demand (COD)

10. Standards for drinking water
This can be broadly classified into two category:
Primary standards:
• This specify the maximum contamination level(MCL) of
various contaminants based on their effect on human
health.
• If the concentration of these contaminants is greater
than permissible MCL, then serious health effect will
occur.
• For eg. : MCL for Pb is 0.05mg/L. If it is exceeded , it
causes liver & kidney damages, mental retardation in
children and gastrointestinal damages.

11. • Secondary standards:
• This vary from place to place depending upon
hardness, colour, taste & odour. They do not have any
anticipated ill effects on health.
The common specifications or standards recommended for
drinking water are as follows:
 It should be colourless & Odourless.
 Good in taste, Not be hot.
 Turbidity should be less than 10ppm.
 Free from objectionable dissolved gases like NH3, H2S and
minerals like lead, arsenic, chromium & manganese salts.
 Alkalinity should not be high. pH in range 7.0- 8.5
 Reasonably soft, total hardness should be less than 500ppm.
 Free from disease causing micro-organisms.

12. Table1 : Water Quality Standards in India
Parameters Level WHO standard
pH
Total hardness
Turbidity
Chlorides (as Cl)
Cyanide (as CN)
PAH
Fluoride (as F)
Nitrate (as NO3)
Phenols
Sulphate (as SO4)
Manganese
Mercury
Iron
Copper
Cadmium
Chromium
Lead
Arsenic
Zinc
Magnesium
6.3-9.2
600 ppm
25 ppm
1000 ppm
0.05 ppm
0.2 ppm
1.5 ppm
45 ppm
2 ppm
400 ppm
0.5 ppm
0.001 ppm
1 ppm
1.5 ppm
0.01 ppm
0.05 ppm
0.1 ppm
0.05 ppm
15 ppm
150 ppm

13. Methods of treatment of water for domestic
and industrial purposes:
• Actual treatment method adopted, depends upon the exact
nature of impurities present in raw water.
• Table2 lists the types of impurities and process to be
employed for removing them.
Table 2: Treatment process for drinking water
S.No. Impurity Present Process used for Removal
1. Floating matter such as leaves, plastics,
wood pieces etc.
Screening
2. Suspended impurity such as sand, clay etc. Sedimentation
3. Fine suspended inorganic matter Sedimentation with coagulation
4. Microorganisms and colloidal impurities Filtration
5. Pathogenic bacteria Disinfection

14. Screening
• It is process of removing
floating matter such as
leaves, plastics waste,
wood pieces etc.
• Raw water is passed
through screens having
holes, the floating
matter is retained by
them and water is
allowed to pass.

15. Sedimentation
• It is a process of removing relatively large particles
(suspended solids) into large reservoirs settlement tank in
which it is left for a few days or even a week, where the
suspended impurities partially sink to the tank.
• Factors affecting the rate of sedimentation:
• Flow velocity of water
• Temperature of water
• Size , shape and specific gravity of suspended matter
 Sedimentation of standing water is carried out by allowing
the large volume of water to stand in big tanks for about
one day to a weak. Suspended large particles are settled in
the bottom. Supernatant water is taken out.
 70-75% suspended impurities are removed by
sedimentation and this process is very slow.

16. Fig.: Sedimentation for removal of coarse suspended impurities

17. Sedimentation with Coagulation
• Finally divided silica, clay and organic matter do
not settle down easily .
• Chemically assisted sedimentation is coagulation.
• Common coagulants:
I. Alums- K2SO4.Al2(SO4)3.24H2O(potashAlum),
NH4Fe(SO4)2.12H2O(FerricAlum) are most commonly used
alums.
II. Ferrous sulphate (copperas) - FeSO4.7H2O
III. Ferric Chloride – FeCl3
IV. Sodium Aluminate - NaAlO2
• About 95% of suspended particles are removed
by coagulation.

18. Mechanism of removal of colloidal particles
It includes the following
steps:
• Adsorption
• Mechanical entanglement
• Electrical attraction of
oppositely charged
particles.
• Neutralization of
electrical charge
• Flocculation
• Settling of colloidal
impurities at the bottom.
Fig.: illustration of action of coagulants

19. Reactions of coagulation
• Al2(SO4)3 + 6H2O → 2Al (OH)3 + 3H2SO4
• NaAlO2 + 2H2O → NaOH + Al(OH)3
• Al2(SO4)3 + 6NaAlO2 + l2H2O → 8Al(OH)3 + 3Na2SO4.
• FeSO4 + H2O → Fe(OH)2 + H2SO4.
• 2Fe (OH)2 + [O] + H2O → 2Fe(OH)3

20. Filtration
• For removal of fine
suspended particles,
turbidity, odour, colour ,
taste and microorganisms
filtration of water is carried
out.
• Different types of filter like
gravity filter, slow & Fast
sand filters and pressure
filters are used.
Gravity Filtration:
Solid impurities entered from
the top and is forced by gravity
through layer of sand and
gravels.
Fig.: Gravity Filter

21. Activated Carbon Filtration
•It involves adsorption of one
material on the surface of second
solid substance based on opposite
electrical charge of each material.
•Activated carbon adsorbs the taste
& odour impurities in water ,leaving
the water taste and odour free.
Uses:
For eliminating certain hazardous
compounds related to
industrial wastes, chemicals &
pesticides.
For removing unpleasant tastes &
odours caused by decaying
organic matter, dissolved gases
& residual chlorine.
Fig.: Cartridge type activated carbon filter