This document discusses sources of water, importance of safe water, qualities of safe water, international standards for drinking water quality, and acceptability variables for physical characteristics and inorganic/chemical components. It also covers water purification methods, hardness of water treatment, chlorination process, prevention of waterborne diseases, water examination, and government action plans for water sanitation and supply.

1. Safe Water

2. Sources of Water
• Rain Water
• Surface Water e.g., river, tanks, lakes
• Ground Water
• Sea is the basic of all sources of water

3. Importance
• Physiological importance
• Domestic importance
• Public importance
• Occupational importance
• Agricultural importance
• Cultural importance

4. Qualities of safe and wholesome water
• Free from pathogenic agents
• Free from harmful chemicals
• Pleasant to taste
• Usable for domestic purposes

5. Quality of Water and International Standards
• The recommended variables to be implemented regarding standard
quality of drinking water:
• Acceptability variables: Physical characteristics, inorganic
components
• Microbiological variables: Bacteriological indicators, Virological
presence, Biological aspects
• Chemical variables: Inorganic and organic components
• Radiological variables: Gross ß activity 1.0 Bq/L and gross ɑ
activity 0.1 Bq/L

6. Acceptability Variables
S.No. Physical Characteristics Acceptable Value
1. Colour: Should be colourless < 15 TCU
2. Turbidity: Free from turbidity <5 NTU
3. Odour & Taste: Odourless and potable No special standard
4. Temperature Drinkable temperature, cool water preferred

7. Acceptability Variables
S.No. Inorganic Component Acceptable Value
1. Hardness 300 mg/L
2. pH 6.5 – 8.5
3. Dissolved oxygen No special standards
4. Chlorides < 200 mg/L
5. Ammonia: indicates sewage pollution or infection -
6. Sodium < 200 mg/L
7. Hydrogen sulphide < 0.05 mg/L
8. Iron < 0.3 mg/L
9. Sulphate < 250 mg/L
10. Zinc < 3 mg/L
11. Copper < 1 mg/L
12. Aluminium < 0.2 mg/L
13. Total dissolved solids < 1000 mg/L

8. Acceptability Variables
S.No. Chemical Component Maximum Limit
1. Arsenic 0.01 mg/L
2. Barium 0.7 mg/L
3. Cyanide 0.07 mg/L
4. Copper 2 mg/L
5. Fluoride 1.5 mg/L
6. Mercury 0.001 mg/L
7. Carbon tetrachloride 2 µg/L
8. Vinyl chloride 55 µg/L
9. Benzene 10 µg/L
10. Ethylbenzene 300 µg/L
11. Aldrin 0.03 µg/L
12. Chlordane 0.2 µg/L
13. DDT, Lindane 2 µg/L
14. Hexachlorobenzene 1 µg/L
15. Methoxychlor 20 µg/L

9. Hardness of Water
• Is expressed in meq/L
• 1 meq/L = 50 mg of CaCO₃ in 1 L of water or 50 PPM
• If quantity > 300 mg/L of water, water is regarded as hard
• In drinking water, quantity may be between 50-150 mg/L
• Treatment of Hardness
• Boiling
• Mixing (lime, sodium carbonate)
• Base Exchange Methods (sodium permutit - compound of sodium,
aluminium and silica – exchanges sodium for calcium and
magnesium)

10. Water Purification
1. Natural Purification
• Evaporation of water
• Storage of water, decantation and automatic purification of flowing
water
• Effects of aeration, oxidation and sunlight
• Filtration through layers of soil
• Biological purification (consumption of impurities by aquatic animals)

11. 2. Purification at Small Scale
• Purification of domestic Water
• Filtration or use of domestic filter (Berkefeld or Katadyn filter)
• Boiling
• Chemical process: Use of bleaching powder (2.5 gm in 1000 L of water) ,
alum, iodine
3. Purification at Large Scale
• Storage
• Filtration
• Chlorination

12. Chlorination
• Removes pathogenic bacteria from water and makes it potable
• Cl2 + H2O HCl + HOCl
• HOCl H + OCl
• The disinfecting action of this chemical is due to hypochlorous acid
and hypochlorite ions.
• Precautions to be taken in the chlorination process:
• Chlorine demand of Water
• Amount of free residual chlorine
• Contact period
• Procedure of chlorination

13. Prevention from Waterborne Diseases
Waterborne diseases
• viral hepatitis, polio, cholera, roundworm may occur due to the presence of
infective agents
• fluorosis and other toxicities due to chemical change in water
Prevention
• Practicing good hygiene: hand washing, short nails
• Drinking safe potable water
• Thoroughly filtered
• Stored in a hygienic place
• If water purification system is absent, practice boiling and cooling
• Maintenance of public water supply system, sanitation facilities, cleanliness in
home surrounding

14. Water Examination
• Sanitation survey: nature of water supply, source, distribution system,
method of use and environment of area around the water source
• Sampling of water
• Water examining techniques: physical, chemical and bacteriological

15. Action plan implemented by central and state
government for sanitation & supply of water
• Establishing urban development fund to develop infrastructure
• Making responsible urban and rural autonomous bodies
• Encouraging participation of community, NGO and private sectors
• Developing low cost technique for maintenance and construction of
sanitation and water supply projects
• Training of personnel
• Discouraging free water supply in rural areas
• Establishing water supply and sanitation cell
• Giving special attention to agriculture and irrigation management

16. • Recharging of rainwater to increase the level of ground water
• Experimenting on water conservation
• Better management for water conservation
• Restricting the uncontrolled exploitation of ground water
• Making sea water potable
• Finding additional sources of water

17. Thanky
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