2. Overview
c__________________ drinking
water has the greatest impact on
human health for > 50% of world’s population
worldwide d___________ due to contaminated
drinking water are approximately 14,000 - 25,000 per
day
25% of h______________ b______ occupied by
people infected with waterborne illnesses
currently the world’s population that lack’s a_________
to “safe” drinking water is 18% or 1.1 billion (Johannesburg World
Summit on Sustainable Development, 2002)
3. World Water
More than 5 million people die each year from diseases
caused by u _ drinking water, lack of sanitation, and
insufficient water for h_________. In fact, over 2 million deaths occur
each year from water-related diarrhea alone. At any given time, almost
half of the people in developing countries suffer from water-related
d________.
Insufficient s_______of water and sanitation disproportionately affect
women, children, and the poor. The majority of deaths from water-
related diarrhea are among children under 15, and women.
Agriculture accounts for more than _____ percent of global water
consumption. The inefficient use of water for irrigation has led to
depletion of groundwater resources in many of the world’s most
important agricultural regions, and is the primary source of
g___________ pollution in parts of Europe, the US, and Asia.
4. INTRODUCTION
Water treatment is the process of removing
contaminants from raw water and household
water.
It includes physical, chemical, and biological
processes to remove physical, chemical and
biological contaminants.
Its objective is to produce an environmentally safe
water.
5. Flow diagram of Water Treatment
plant
Screening
Coagulation
Flocculation
Sedimentation
Filtration
Disinfection
Storage
Distribution
Raw water
Alum
Polymers
Cl2
sludge
sludge
sludge
6. Screening
Screening is done to carry out the remove of heavy
suspended solid from the water.
like:- plants, stones, animals ,trees, etc.
Screening is generally adopted for the treatment of surface
water. Screening is done with the help of
1. Coarse Screen 2. Fine Screen
Removes large solids – Logs, branches,rags,fish
Simple process
Protects pumps and pipes in WTP
7. Aeration
Aeration:- It is the process in which water of
brought intimate contact of air .
It removes undesirable gases like Co2 , H2S.
It removes undesirable organic mater.
8. Sedimentation
the oldest form of water treatment
Sedimentation is the process removes
suspended particle form the water which could
not be removes in the screening process.
uses gravity to separate particles from water
often follows coagulation and flocculation
9.
10. Coagulation
Coagulation is a physical-chemical process whereby
particles are destabilized
Several mechanisms
adsorption of cations onto negatively charged
particles
The standard coagulant for water supply is Alum
[Al2(SO4)3*14.3H2O]
Typically 5 mg/L to 50 mg/L alum is used
The chemistry is complex with many possible species
formed such as AlOH+2
, Al(OH)2
+
, and Al7(OH)17
+4
11. Flocculation
Coagulation has destabilized the particles by
reducing the energy barrier or It is the process in
which naturalize particle are in contact with each
other , so as to promote their resulting in
increased size.
Now we want to get the particles to collide
We need relative motion between particles
Brownian motion (effective for particles smaller than
1 µm)
Differential sedimentation (big particles hit smaller
particles)
12. Filtration
It is carry out for the removes of fine suspended
particles and flow from the water. Filteration also
remove organic matter,micro organism, minerals
form the water
Types of filters- 1.Slow sand filter
2.Rapid sand filter
3.Pressure filter
13. Slow Sand Filtration
First filters to be used on a widespread basis
Fine sand with an effective size of 0.2 mm
Low flow rates (10 - 40 cm/hr)
Schmutzdecke (filter cake ) forms on top of the
filter
causes high head loss
must be removed periodically
Used without coagulation/flocculation!
15. Disinfection
Disinfection: operations aimed at killing or inactivating
pathogenic microorganisms or Disinfection is the
destruction of microorganisms in drinking water to safe
levels.
Disinfection techniques include physical (boiling,
ultraviolet light) and chemical methods (chlorine,
bromine, iodine, and ozone).
Chlorine -Chlorination is a cheap, effective, relatively
harmless (and therefore most popular) disinfection
method.
chlorine gas - Poisonous gas – risk of a leak
sodium hypochlorite (bleach)
16. Softening
Softening:- Softening is done in order to carry out the
remove of the hardness form the water.
Removal of temporary hardness by simple boiling.
Removal of permanent hardness
1. Lime soda process
2. Base exchange process
3. Demineralization process
17. Minor treatment
A) With activated carbon
Due to adsorption property it removes taste, odour and
colour.
It remove phenol type impurity.
It is added before or after coagulation but before filteration.
B) Treatment with copper sulphate
When added in reservoirs, it checks the growth of algae
and kills algae to some extent.
It also helps in removing colour, taste and odour.
CuSO4 is added just at entry of distribution system
Dose – 0.5-0.75 mg/l
18. C) Defluoridation (Removal of fluorine)
Removing fluorides from water
Methods – 1) Prashanti techniques
2) Nalgonda techniques
3) Reverse osmosis process
19. Conclusion :
PH Should be ranges from 6.5- 8
Alkalinity of drinking water should be < 200
Hardness of water should be in between 200-
250
Editor's Notes
A large variety of crock pot type containers (shown in upper images here) which contained radium were on the market during the 1920s. The radioactive decay of radium produced radon in the water stored in these containers. A popular company of the times called their crock the Revigator. It is depicted in the top image on the left. A variety of devices were also designed to be placed into any type of container with water to produce radon water. These devices were called emanators because radon gas was released from them to the water. Unfortunately for the persons who could afford any of these devices, they actually worked quite well.
Radon water could also be produced from addition of pills or by addition of drops from a radioactive concentrate. This image shows a package of radione capsules that could be dissolved in water.
This image shows containers of radium salts on the left and a liquid concentrate on the left that could be consumed as is or used to add radioactivity to drinking water. The Radithor on the right was what killed Eben Byers.