Lecture -3 Cold water supply system.pptx

The presentation on Cold Water Supply explored the fundamental principles of water distribution in buildings. It covered sources of cold water, including municipal supply, wells, and rainwater harvesting. Key components such as storage tanks, pipes, valves, and pumps were discussed for efficient water delivery. Various distribution systems, including direct and indirect supply methods, were analyzed for residential and commercial applications. The presentation emphasized water quality, pressure regulation, and contamination prevention. Common issues like pipe corrosion, leaks, and pressure drops were addressed along with maintenance strategies. Diagrams and case studies illustrated system layouts and best practices for optimal performance.

1. Cold water supply system

2. Importance of water No life can exist without water It is as essential for life as air Is Two third of human body is constituted of water Provides of luxuries and comforts to human being

3. Components of a protected water supply scheme Source of water Intake Treatment Distribution

4. Rain Cycle Sources of Water Supply Lakes, streams, rivers, reservoirs, run off from roofs and paved areas. Underground sources † Shallow wells, deep wells, artesian wells, artesian springs, land springs. Surface sources

5. Acid A substance containing hydrogen which can be replaced by other elements. Litmus paper in the presence of acidic water turns red. A substance which will neutralise acid by accepting its hydrogen ions (H+). Litmus paper in the presence of alkaline water turns blue. pH < 7 indicates acidity pH > 7 indicates alkalinity pH = 7 chemically pure Alkali

6. Filtration of Water Pressure filter Rate of filtration 4 to 12 m3 per m2 per hour. To backwash, valve A is closed, and valves B and C opened. Compressed air clears the sand of dirt. Diameter = 2.4 m.

7. Slow sand filter bed Rate of filtration 0.2 to 1,15 m3 per m2 per hour. Filter beds can occupy large areas and the top layer of sand will require removal and cleaning at periodic intervals.

8. Small domestic filter The unglazed porcelain cylinder will arrest very fine particles of dirt and even micro-organisms. The cylinder can be removed and sterilised in boiling water for 10 minutes

9. Sterilisation and Softening Sterilisation by chlorine injection water used for drinking must be sterilised . Chlorine is generally used for this purpose to destroy organic matter. Minute quantities (0.1 to 0.3 p.p.m. ) are normally added after the filtration process

10. Softening of hard water by base exchange process Sodium zeolites exchange their sodium base for calcium (chalk) or magnesium bases in the water. Sodium zeolite plus calcium carbonate or sulphate becomes calcium zeolite plus sodium carbonate or sulphate. To regenerate, salt is added; calcium zeolite plus sodium chloride (salt) becomes sodium zeolite plus calcium chloride which is flushed away

11. Storage and Distribution of Water Gravitational distribution The water from upland gathering grounds is impounded in a reservoir. From this point the water is filtered and chlorinated before serving an inhabited area at lower level. There are no pumping costs

12. Pumped distribution Water extracted from a river is pumped into a settlement tank, subsequently filtered and chlorinated. Pump maintenance and running costs make this process more expensive than gravity systems.

13. Ring main distribution water mains supplying a town or village may be in the form of a grid. This is preferable to radial distribution as sections can be isolated with minimal disruption to the remaining system and there is no more opportunity for water to maintain a flow