Explanation of water purification and waterworks.

1. Topic-1Topic-1
WaTer purificaTionWaTer purificaTion

2. PURIFICATION OF WATERPURIFICATION OF WATER
 LARGE SCALELARGE SCALE
Storage Filtration DisinfectionStorage Filtration Disinfection
 SMALL SCALE (DOMESTIC)SMALL SCALE (DOMESTIC)
A. Household purificationA. Household purification
–– BoilingBoiling
–– Chemical disinfection :Chemical disinfection :
Bleaching powder, Chlorine solution , High test hypochlorite(HTH),Bleaching powder, Chlorine solution , High test hypochlorite(HTH),
Chlorine tablets , Iodine, Potassium permagnateChlorine tablets , Iodine, Potassium permagnate
–– Household filtration :Household filtration :
Ceramic filtersCeramic filters
B. Disinfection of wellB. Disinfection of well
a. By adding bleaching powdera. By adding bleaching powder
b. Double pot methodb. Double pot method

3. STORAGE
 In Natural / Artificial Reservoirs
 Effects of storage:
• Physical: Gravity – 90%suspended impurities settle down in one day
Oxidizing action
•Chemical: Organic matter Nitrates, Free Ammonia
Aerobic bacteria, dissolved O2
•Biological: Only 10% bacteria remains at the end of 1 week
Optimum period of storage: 2 weeks

4. FILTRATION
Water pass through porous media
SLOW SAND / BIOLOGICAL FILTERS
Used first in 19th
century in scotland
Elements of slow sand filter
• Filter Box:
a. Supernatant water
b. Sand bed
c. Under drainage system
• Filter control valves

5. DISINFECTION
Criteria for satisfactory disinfectant:
1. Destroy the pathogenic organism without being influenced
from properties of water (pH, temp. etc.) within a time period
2. Should not be toxic and colour imparting or leave the water
impotable
3. Available, cheap,easy to use
4. Leave the residual concentration to deal with recontamination
5. Detectable by rapid,simple techniques in small concentration
ranges to permit the control of disinfection process

6. Chlorination
METHOD OF CHLORINATION
Chlorinating equipment (Paterson’s chloronome) for adding gaseous chlorine
Action:
Kills pathogenic bacteria (no effect on spores and viruses)
Oxidize iron, manganese and hydrogen sulphide
Reduces taste and odours
Controls algae
Maintains residual disinfection
Mechanism of action:
1. H2O+Cl2 (at pH 7) ------- HCl + HOCl (main disinfectant)
HOCl (at pH > 8.5) -------- H+
+ OCl-
(minor action)
2. NH3+ Cl2 -------- NH2Cl/NHCl2/NCl3 + H2O
(Mono, Di ,Tri Chloramines)

7. PURIFICATION OF WATER ON SMALL SCALE
A . HOUSEHOLD PURIFICATION:
1.BOILING
Rolling boil for 10 min.
Kills all bacteria,spores,cysts,ova,remives temporary hardness
No residual protection
2.CHEMICAL DISINFECTION
a. Bleaching powder: White powder,pungent smell
33% available chlorine
Unstable
Storage in dark,cool,dry place in a closed container
Prepared by passing chlorine gas over lime (CaO)
Chlorinated lime(CaOCl2)-another name
Stabilized bleach-Bleaching powder mixed with excess of lime
Chlorine solution:
200 gm bleaching powder (25% available chlorine) + 1 litre water = 5% solution
1 drop of this solution---For disinfection of 1 L water

8. b. HTH/Perchloron:
High strength Ca Hypochlorite
70% available chlorine
1 gm/L of water
c. Chlorine tablets:
NEERI developed cheaper good tablets 1 tab(0.5g) for 20 L water
d. Iodine :
2 drops (2% solution in alcohol) for 1 L water
Contact time 30 minutes
Used only in emergency situation
e. Potassium permangnate: Expensive,unreliable,not recommended
f. Alum : For turbidity reduction: 0.4-1.6 g/20 L water

9. 3. FILTRATION AT HOUSEHOLD LEVEL
1.FOUR GHARA METHOD: Top: Muddy water, II: Sand,III: Charcoal,
(MSCE) IV: Empty ghara to collect filtered water
2. CERAMIC FILTERS
Water pass through micro-pores of candle placed inside the water
container.
Bacteria: Unable to pass through the pores,
Virus: Can pass through the pores
• PASTEUR CHAMBERLAND FILTER:
porcelain candles, used in labs & dispensaries.
• BERKEFELD FILTER:
infusorial earth (keiselgurh) candles, less reliable

10. KATADYN FILTER:
• katadyn: activated form of silver
• filter coated with silver catalyst (oligodynamic action)
• oligodynamic action: certain metals in very small doses act as
powerful germicide
Cleaning of filter:
• candles scrubbing with a hard brush - every 3 days,
• boiling of candles-once in a week

11. TOPIC-2TOPIC-2
Tyndall effeCTTyndall effeCT

12. Tyndall effeCTTyndall effeCT
The Tyndall effect, also known as Tyndall scattering,
is light scattering by particles in a colloid or particles in a
fine suspension. It is named after the 19th-century
physicist John Tyndall. It is similar to Rayleigh scattering, in
that the intensity of the scattered light depends on the
fourth power of the frequency, so blue light is scattered
much more strongly than red light. An example in everyday
life is the blue colour sometimes seen in the smoke emitted
by motorcycles, in particular two-stroke machines where
the burnt engine oil provides the particles.

13. Under the Tyndall effect, the longer-wavelength light is
more transmitted while the shorter-wavelength light is
more reflected via scattering. An analogy to this wavelength
dependency is that longwave electromagnetic waves such
as radio waves are able to pass through the walls of
buildings, while shortwave electromagnetic waves such as
light waves are stopped and reflected by the wallsand
density of particles in aerosols and other colloidal matter
(see ultramicroscope and turbidimeter).

14. The Tyndall effect is seen when light-scattering particulate-
matter is dispersed in an otherwise-light-transmitting
medium, when the cross-section of an individual particulate
is the range of roughly between 40 and 900 nanometers,
i.e., somewhat below or near the wavelength of visible light
(400–750 nanometers). It is particularly applicable to
colloidal mixtures and suspensions; for example, the
Tyndall effect is used commercially to determine the size

15. Blue IrIses
A blue iris in an eye is due to Tyndall scattering in a turbid
layer in the iris. Brown and black irises have the same
layer except with more melanin in it. The melanin absorbs
light. In the absence of melanin, the layer is translucent
(i.e., the light passing through is randomly and diffusely
scattered) and a noticeable portion of the light that enters
this turbid layer re-emerges via a scattered path. That is,
there is backscatter, the redirection of the light waves back
out to the open air. Scattering takes place to a greater
extent at the shorter wavelengths.

16. The longer wavelengths tend to pass straight through the
turbid layer with unaltered paths, and then encounter the
next layer further back in the iris, which is a light absorber.
Thus, the longer wavelengths are not reflected (by
scattering) back to the open air as much as the shorter
wavelengths are. Since the shorter wavelengths are the
blue wavelengths, this gives rise to a blue hue in the light
that comes out of the eye.[2][3]
The blue iris is an example of
a structural color, in contradistinction to a pigment color.
The complete absence of pigment in eyes (albinism)
causes the eye to appear red, due to the visibility of the red
of the retina through the iris.[4]

17. PhenOmena nOT Tyndall sCaTTerIng
On a day when the sky is overcast, the sunlight passes
through the turbid layer of the clouds, resulting in
scattered, diffuse light on the ground. This does not exhibit
Tyndall scattering because the cloud droplets are larger
than the wavelength of light and scatter all colors
approximately equally. On a day when the sky is cloud-free,
the sky's color is blue in consequence of light scattering,
but this is not termed Tyndall scattering (instead it is
Rayleigh scattering) because the scattering particles are
the molecules of the air, which are much smaller than the
wavelength of the light.[5]
On occasion, the term Tyndall
effect is incorrectly applied to light scattering by
macroscopic dust particles in the air.

18. TOPIC-3TOPIC-3
seParaTIOn Of gases frOm aIrseParaTIOn Of gases frOm aIr

19. SEPARATING GASESSEPARATING GASES
Air is a mixture of gases, consisting primarily of nitrogen
(78 %), oxygen (21 %) and the inert gas argon (0.9 %). The
remaining 0.1 % is made up mostly of carbon dioxide and
the inert gases neon, helium, krypton and xenon. Air can
be separated into its components by means of distillation in
special units. So-called air fractionating plants employ a
thermal process known as cryogenic rectification to
separate the individual components from one another in
order to produce high-purity nitrogen, oxygen and argon in
liquid and gaseous form.

20. METhodS of SEPARATIoNMEThodS of SEPARATIoN
 Compression of air
Ambient air is drawn in, filtered and compressed to approx. 6 bar by a
compressor.
 Precooling of air
To separate air into its components, it must first be liquefied at an extremely low
temperature. As a first step, the compressed air is precooled with chilled water.
 Separation of air
Separation of air into pure oxygen and pure nitrogen is performed in two
columns, the medium-pressure and the low-pressure columns. The difference in
boiling point of the constituents is exploited for the separation process. Oxygen
becomes a liquid at -183°C and nitrogen at -196°C. The continuous evaporation
and condensation brought about by the intense exchange of matter and heat
between the rising steam and the descending liquid produces pure nitrogen at
the top of the low-pressure column and pure oxygen at the bottom. Argon is
separated in additional columns and involves some extra steps in the process.

21.  Cooling of air
Because the gases which make up air only liquefy at very low temperatures,
the purified air in the main heat exchanger is cooled to approx. -175°C. The
cooling is achieved by means of internal heat exchange, in which the flows
of cold gas generated during the process cool the compressed air. Rapid
reduction of the pressure then causes the compressed air to cool further,
whereby it undergoes partial liquefaction. Now the air is ready for the
separating column, where the actual separation takes place.
 Withdrawal and storage
Gaseous oxygen and nitrogen are fed into pipelines for transport to users,
e.g. steelworks. In liquid form, oxygen, nitrogen and argon are stored in
tanks and transported to customers by road tankers.
 Purification of air
Impurities such as water vapour and carbon dioxide are then removed from
the air in a so-called molecular sieve.

22. ToPIC-4ToPIC-4
dIffRENCE BETwEENdIffRENCE BETwEEN
PhYSICAL ANd ChEMICALPhYSICAL ANd ChEMICAL
ChANGEChANGE

23. PHYSICAL PROPERTIESPHYSICAL PROPERTIES
The luster of an element is defined as the
way it reacts to light. Luster is a quality of a
metal. Almost all of the metals, transition
metals, and metalloids are lustrous. The
non-metals and gases are not lustrous. For
example, oxygen and bromine are not
lustrous.

24. Malleability
 Malleability is also a quality of metals. Metals
are said to be malleable. This means that the
metals can deform under an amount of stress.
For example, if you can hit a metal with a mallet
and it deforms, it is malleable. Also, a paperclip
can be shaped with bare hands.

25. DUCTIBILITYDUCTIBILITY
 In materials science, this property is
called ductility. For example, raw copper
can be obtained and it can be purified and
wrapped into a cord. Once again, this
property is characteristic of mainly metals,
non metals do not possess this quality.

26. Density
 The density of an object is its mass divided by its
volume (d=m/v). A substance will have a higher density if
it has more mass in a fixed amount of volume. For
example, take a ball of metal, roughly the size of a
baseball, compressed from raw metal. Compare this to a
baseball made of paper. The baseball made of metal has
a much greater weight to it in the same amount of
volume. Therefore the baseball made out of metal has a
much higher density. The density of an object will also
determine whether it will sink or float in a particular
chemical. Water for example has a density of 1g/cm3
.
Any substance with a density lower than that will float,
while any substance with a density above that will sink.

27. CHEMICAL PROPERTIESCHEMICAL PROPERTIES
Change in Temperature
A change in temperature is characteristic of a chemical
change. During an experiment, one could dip a
thermometer into a beaker or Erlenmeyer Flask to verify a
temperature change. If temperature increases, as it does in
most reactions, a chemical change is likely to be occurring.
This is different from the physical temperature change.
During a physical temperature change, one substance,
such as water is being heated. However, in this case, one
compound is mixed in with another, and these reactants
produce a product. When the reactants are mixed, the
temperature change caused by the reaction is an indicator
of a chemical change.

28. Change in Color
A change in color is also another characteristic
of a chemical reaction taking place. For example, if
one were to observe the rusting of metal over time,
one would realized that the metal has changed
color and turned orange. This change in color is
evidence of a chemical reaction. However, one
must be careful; sometimes a change in color is
simply the mixing of two colors, but no real change
in the composition of the substances in
question. EG. 4Fe+3O2+6H2O→4Fe(OH)3

29. notiCeable odour
 When two or more compounds or
elements are mixed and a scent or
odor is present, a chemical reaction has
taken place. For example, when an egg
begins to smell, (a rotten egg) a chemical
reaction has taken place. This is the result
of a chemical decomposition.

30. Formation oF a PreCiPitate
The formation of a precipitate may be one of
the most common signs of a chemical reaction
taking place. A precipitate is defined to be a solid
that forms inside of a solution or another solid.
Precipitates should not be confused with
suspensions, which are solutions that are
homogeneous fluids with particles floating about in
them. For instance, when a soluble carbonate
reacts with Barium, a Barium Carbonate
precipitate can be observed. EG. Ba2+(aq)
+CO2−3(aq)→BaCO)3(s)

31. Formation oF bubbles
The formation of bubbles, or rather a gas, is
another indicator of a chemical reaction taking
place. When bubbles form, a temperature change
could also be taking place. Temperature change
and formation of bubbles often occur together. For
example, in the following image, one can see a
gas spewing. This is the formation of a gas. EG.
Na2CO3+2HCl→2NaCl+H2O+CO2

32. diFFrenCe betWeen ProPertiesdiFFrenCe betWeen ProPerties
 The difference between a physical reaction and a
chemical reaction is composition. In a chemical
reaction, there is a change in the composition of the
substances in question; in a physical change there is a
difference in the appearance, smell, or simple display of
a sample of matter without a change in
composition. Although we call them physical "reactions,"
no reaction is actually occurring. In order for a reaction to
take place, there must be a change in the elemental
composition of the substance in question. Thus, we shall
simply refer to physical "reactions" as physical changes
from now on.

33. thanKYouthanKYou
 BY Almighty-CreatorBY Almighty-Creator