2. What is Water purification?
Water purification is the process of removing undesirable
chemicals, biological contaminants, suspended solids and
gases from water. The goal is to produce water fit for a
specific purpose. The methods used include physical
processes such as filtration, sedimentation, and distillation;
biological processes such as slow sand filters or biologically
active carbon; chemical processes such as flocculation and
chlorination and the use of u.v. radiation.
3. Sources of water
1.Groundwater:Soil and rock layers naturally filter the ground water
to a high degree of clarity and often, it does not require additional
treatment besides adding chlorine or chloramines as secondary
disinfectants.
2.Upland lakes and reservoirs: Bacteria and pathogen levels are
usually low, but some bacteria, protozoa or algae will be present.
Many upland sources have low pH which require adjustment.
4. 3.Rivers, canals and low land reservoirs: Low land surface waters will
have a significant bacterial load and may also contain algae, suspended
solids and a variety of dissolved constituents.
4.Atmospheric water generation is a new technology that can provide
high quality drinking water by extracting water from the air by cooling the
air and thus condensing water vapor.
5.Surface Water: Freshwater bodies that are open to the atmosphere
and are not designated as groundwater are termed surface waters.
5. Goals:
The goals of the treatment are to remove unwanted constituents in
the water and to make it safe to drink or fit for a specific purpose in
industry or medical applications. Widely varied techniques are
available to remove contaminants like fine solids, micro-organisms
and some dissolved inorganic and organic materials, or
environmental persistent pharmaceutical pollutants. The choice of
method will depend on the quality of the water being treated, the
cost of the treatment process and the quality standards expected of
the processed water.
6. Pretreatment
1.Pumping and containment โ The majority of water must be pumped
from its source or directed into pipes or holding tanks. To avoid adding
contaminants to the water, this physical infrastructure must be made from
appropriate materials and constructed so that accidental contamination
does not occur.
2.Screening โ The first step in purifying surface water is to remove large
debris such as sticks, leaves, rubbish and other large particles which may
interfere with subsequent purification steps. Most deep groundwater does
not need screening before other purification steps.
7. 3.Storage โ Water from rivers may also be stored in bankside
reservoirs for periods between a few days and many months to allow
natural biological purification to take place. This is especially important if
treatment is by slow sand filters. Storage reservoirs also provide a buffer
against short periods of drought or to allow water supply to be
maintained during transitory pollution incidents in the source river.
4.Pre-chlorination โ In many plants the incoming water was chlorinated
to minimize the growth of fouling organisms on the pipe-work and tanks.
Because of the potential adverse quality effects (see chlorine below),
this has largely been discontinued
8. Water purification process
Materials required:
โ Alum
โ Charcoal
โ fine sand
โ pebbles
โ gravels
โ icecream sticks or dry grass
โ Cloth
9. Sedimentation:
The water sample obtained from different source is
allowed to sediment for few hours so that the dirt
particles will settle down . For this process alum is used.
Alum allows the dirt particles settle at the bottom and get
results at a faster rate. The water obtained after
Sedimentation is allowed to pass through water filter.
10. Water filter experiment:
The water filter consists of different layers namely;
1. Gravels
2. Pebbles
3. Fine sand
4. Charcoal
11. Water sample testing
The water sample collected can be categorized into two types ,
namely,
1) Soft water
2) Hard water
The water containing hardness is either permanent or
temporary.
a) Temporary hardness:
It can be removed by simply boiling the water and
separate the precipitate.
b) Permanent hardness:
It can be removed by several methods like zeolite
process, ion exchange process, reverse osmosis and electro dialysis.
12. The water sample free from hardness is
allowed to pass through the water filter
after Sedimentation. The different layers
of charcoal, fine sand, pebbles and
gravels are arranges from top to bottom
respectively. Each layer having its own
significance help to remove impurities
and water free from dirt particles is
obtained. The pure water is collected in
bottom bottle and use as per required.
The water obtained through this filter is
safe to use for several domestic
purposes
13. Uses of each layer:
โ Gravels: Gravel will capture and remove
debris, particles, and sediments from the water
in your pond and deposit that material in
between its grains of gravel where it can now
be further broken down by millions of microbes
(beneficial bacteria) that grow on the surface
of the gravel bed that is filtering your water.
14.
15. โ Fine sand:Filtering swimming pool
water through a layer of fine sand is
one of the oldest forms of filtration. ...
In addition, gelatinous substances and
oils cling to the fine grains of the sand.
This process of coagulation enhances
the filtering efficiency of sand in
capturing very small dirt particles.
16. โ Charcoal: It is natural and effective
at removing many toxins from the
water, such as volatile organic
compounds and chlorine, without the
use of chemicals or stripping the
water of salts and minerals.
17. Significance:
1. It doesnโt remove the โgood stuff.โ Drinking water isnโt
just made of hydrogen and oxygen, there are also many other
minerals, in addition to nasty chemicals and impurities, which
make up the composition of water. Due to the chemical
composition and structure of activated charcoal, these filters
attract and absorb unhealthy organic compounds, while allowing
the rest of the minerals to remain in the water.
18. 2. It makes water healthier. Not only do charcoal filters remove a lot of
the nasty stuff from water, they can add things back into your water to make
it healthier. Activated charcoal can add important minerals, such as calcium,
magnesium and iron back into your water to improve the water quality.
3. It improves the flavor. Many people dislike the taste of tap water,
complaining it tastes metallic or has an off-putting aroma. This taste is often
due to the additives, such as chlorine, that are added to tap water to kill
bacteria and pathogens found in reservoirs. Charcoals filters not only
adsorb these nasty tasting chemicals, but they are also highly effective at
removing odors as well, making your drinking water much more palatable.
19. 4. It is cheap. Many water filtration systems can be an expensive,
though necessary, investment for your home. Charcoal filters, on the
other hand, are relatively inexpensive to produce, and those savings
are passed down to the consumer.
5. They are easy to maintain. Your different layers in the water
should be replaced. However, this depends on the amount of water
you use and the water quality in your area. If you are unsure, look at
the clarity of your water, observe whether the taste has changed or
whether the flow rate has decreased. If you notice any of these things,
it may be time to change your filter.
20. Conclusion
Charcoal water filters are one of the most popular types of
water filters on the market for good reason. Activated
charcoal has numerous economic, ecological and health
benefits. Try a charcoal water filter in your home today, and
taste the difference.
21. Reference:
โ Textbbok of Engineering chemistry by S.S. Dara
โ Textbook of Engineering chemistry by Shashi Chawla
โ https://www.google.co.in/Water_purification&ved=2ahUK
EwiVlPCh2O7eAhXBu48KHSkeDGsQFjASegQIABAB&u
sg=AOvVaw38cWLCP5WY4vQpXXfOE9Q6
โ https://www.google.co.in/purification-
5131941.html&ved=2ahUKEwj_wOnp2O7eAhXJQI8KHT
MZCKoQFjAQegQIBRAB&usg=AOvVaw2-
rVWwKmZGGMg7kU9GsGWn
โ Textbook of engineering chemistry by S. Chand