1. Water

2. Importance of Water
Water is one of the most important substances on earth. All plants and animals must have water to survive. If there was no water there would be no life on earth.
Apart from drinking it to survive, people have many other uses for water. These include:
cooking
washing their bodies
washing clothes
washing cooking and eating utensils; such as billies, saucepans, crockery and cutlery
keeping houses and communities clean
recreation; such as swimming pools
keeping plants alive in gardens and parks

3. Importance of water for human body
As a structural component.
As a solvent in the body.
For the regulation of body temperature.
As a heat insulator and padding material.
As a lubricant.

4. Importance of water for other purposes.
Domestic use.
Irrigation
Industrial use.
For generating energy.
Disposal of sewage and other wastes.
Construction of buildings and fire fighting.
For aquatic animals and plants.
For animals.
As a means of transport.

5. Different types of impurities in water
Pure water is colourless, tasteless, and odourless and is chemically composed of just two elements, hydrogen and oxygen. Because water is such a good solvent, it dissolves almost everything that it comes into contact with. Water is known as a ‘universal solvent’. So the water that is available to us from rain, well, streams, rivers, etc. are contaminated and contain many impurities. The usual contaminants and types impurities in water are of the following two main categories:

6. Dissolved impurities. Dissolved impurities mainly consist of salts and minerals. While some minerals are necessary for our consumption, others like arsenic, lead, etc., are harmful. Suspended impurities. Suspended impurities consist of particulate matter like sand, algae, virus and bacteria, which can cause diseases like diarrhoea, gastroenteritis, etc. 

7. Types of water On the basis of purity, water can be classified as:
Clean or pure water
Polluted water.
Contaminated water.
Hard water.
Soft water.

8. Domestic Purification of Water
Physical methods:
Boiling
Boiling is also a very old and popular method of treating water, which neutralizes bacteria and virus quite effectively, though the rest of the suspended and dissolved impurities are not addressed.
Distillation
Distillation involves evaporating water into steam which is then condensed to form water.

9. Chemical methods: Precipitation Germicidal chemicals
Washing soda and alum are used to precipitate the impurities which settle down.
Germicidal chemicals
Chemicals like Potassium permanganate, Copper sulphate,Sodium bisulphite,Lime,Chlorine, Bromine and Nesfield tablets are used.

10. Filtration methods Straining through muslin cloth.
Filtering through materials like Charcoal,Sand,Silicated carbon.
Filtration by Three-Pitcher System in which three pitchers are placed one above the other on a stand. The uppermost pitcher contains sand and the second one contains sand and charcoal. Water flows down from the uppermost pitcher to the last one drop by drop through holes in the pitchers.

11. Domestic water filters
Pasteur chamberland filter
It consists of an unglazed porcelain tube that contains a ring of enameled porcelain through which the inflow pipe fits. The core of the porcelain is made up of a metal pipe with holes through which water flows out and is collected. Inflow is pressurized so filtration occurs under force.

12. Zero B water purifier
REMOVES PHYSICAL IMPURITIES: High quality filter efficiently removes mud, sand, dust & other suspended impurities. Reduces turbidity by 70% Iodinated Resin Technology Permanently kills Bacteria and Viruses that cause water-borne diseases like Polio, Hepatitis, Diarrhea, Typhoid & gives pure drinking water Bacteriostatic Activated Carbon Silver impregnated activated carbon removes excess iodine, chlorine, organics, color, odour and foul taste from water

13. Aqua flo water purifiers
Three stage purification
First being filtration of suspended particles like dust, rust and mud up to 5 microns.
In the next stage the technology enables itself to absorb organic impurities, foul smell & taste, lead, pesticides and volatile organic compounds.
Later in the third and final stage, the ultra violet rays deactivate bacteria, virus, protozoa including cyst and other disease-causing micro-organisms.

14. Reverse Osmosis

15. What is reverse Osmosis?
Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by pushing the water under pressure through a semi- permeable membrane.
Reverse Osmosis, a water treatment method traditionally known for removing salt from seawater, is also used to purify drinking water by forcing untreated water molecules through a semi- permeable membrane or filter. The membrane blocks contaminants and the impurities are subsequently expelled from the environment. The result is pure, clean drinking water.

16. Osmosis
To understand the purpose and process of Reverse Osmosis you must first understand the naturally occurring process of Osmosis.
Osmosis is a naturally occurring phenomenon and one of the most important processes in nature. It is a process where a weaker saline solution will tend to migrate to a strong saline solution. Examples of osmosis are when plant roots absorb water from the soil and our kidneys absorb water from our blood.
Below is a diagram which shows how osmosis works. A solution that is less concentrated will have a natural tendency to migrate to a solution with a higher concentration. concentration.

17. For example, if you had a container full of water with a low salt concentration and another container full of water with a high salt concentration and they were separated by a semi-permeable membrane, then the water with the lower salt concentration would begin to migrate towards the water container with the higher salt .

19. What are some benefits of Reverse osmosis?
Pure, clean drinking water and ice cubes
Removal of unwanted odors or tastes
More robust tasting beverages that are mixed with Reverse Osmosis treated water (coffee, tea, etc.)
Requires minimal maintenance
Convenient- pure, clean water at the touch of a finger
While not practical for purifying public water supply, an in- home Reverse Osmosis system can be cost effective when compared to other home water filtration methods.

20. What are the stages of reverse osmosis?
Since water is a necessity of life, it is important to drink water free from contaminants. To treat water and make it worth drinking, different processes are used and one of best treatment methods is Reverse Osmosis. In this process of water filtration, the water goes through semi permeable membranes with minute pores and becomes clear. The impurities left behind are flushed out. If you do not get the water supply from Municipal Corporation, it becomes important for you to make use of the Reverse Osmosis system in order to treat water and make it worth drinking. There are reverse osmosis systems that have a number of stages. The best out of all these systems are the five stage systems. With the help of these systems, you can be sure that you drink the cleanest water in your home. Here is a brief description of all the five stages through which the water goes before it becomes fit for drinking.

21. The first stage is the removal of sediments from the water
The first stage is the removal of sediments from the water. In this step all the sediments like clay, silt and stones are removed from the water. For this, a 5-micron filter is used. The sediments are filtered in order to make sure that no damage is done to the membrane. The micron filter does not let these particles pass by and thus they are suspended.  The second stage of the Reverse osmosis treatment is the usage of carbon filter. The carbon filter is used to remove the chlorine and other harmful chemicals that enter the water sources. The chemicals can be harmful to human health and thus it is necessary to remove them.

22. The third stage of reverse osmosis treatment generally focuses on passing the water from a dense and compacted carbon filter. The water that we get may have some unpleasant characteristics and this third step helps in the removal of all such characteristics. All the contaminants left in the water are removed at this stage and water becomes almost clean. In the fourth step, water passes through the membrane and all the heavy metals present in the water are removed. Along with the metals, radioactive metals too are removed. In this step, the impurities are drained out of the reverse osmosis system and clean water is separated.

23. The fifth and the last stage in the whole process of reverse osmosis is post filtration. This may be the last step but is the most important of all. In this last stage, the bacteria, chlorine, and bad odor are removed from water. After water passes from this stage, it comes out of the faucet and is perfect for consumption.

24. Conclusion
The threat of harmful contaminants in drinking water can no longer be reasonably ignored. The correlation between contaminated drinking water and many significant diseases and health problems is far too strong to discount. Children, the elderly, and those individuals who already have weakened immune systems, are particularly at risk to drinking water contaminants. Two of the most volatile drinking water contaminants, chlorine and fluoride, are actually treatment additives. Also, lead, another of the more harmful contaminants, enters drinking water after treatment and cannot be regulated by municipal water systems.

25. Therefore, municipal water systems cannot and should not be trusted to provide healthy, clean drinking water. There are many home treatment alternatives that can purify drinking water to a greater extent than city treatment plants. Reverse osmosis and distillation, two of these alternatives, are moderately successful at removing some contaminants, but they are expensive and wasteful. Bottled water, besides being expensive and highly unfeasible as a main drinking water source, is not under the same government regulations as municipal water systems and may actually contain more contaminants than tap water. The absolute best technology now available for treating water and removing undesirable contaminants is water filtration. Water filters, when compared to any other water treatment alternative, will remove more contaminants and provide safer, healthier drinking water.