PURIFICATION AND TREATMENT OF WATER

PURIFICATION AND TREATMENT OF WATER
1. Natural Methods
2. Artificial Methods
- PURIFICATION ON SMALL SCALE
- Purification of Water on Large Scale

• WATER TREATMENT PLANT STAGES
1. SCREENING
2. AERATION
3. PH CORRECTION
4. COAGULATION AND FLOCCULATION
5. SEDIMENTATION
6. PRE-CHLORINATION AND DECHLORINATION
7. FILTRATION
8. DISINFECTION
9. PH ADJUSTMENT

• Complete Cycle of Water Treatment

1. PURIFICATION AND TREATMENT OF WATER PRESENTED BY : KESHAV KUMAR SINGH Reg. No.:- Y19266023 Deptt. of Chemistry DHSGU Sagar (M.P.)

2. Water purification is the removal of contaminants from raw water to produce drinking water that is pure enough for human consumption or for industrial use . – Many contaminants are removed to improve water’s taste, smell & appearance. – Small amounts of disinfectant is left intentionally at the end of a treatment process to reduce risk of re- contamination in the distribution. – It is not possible to tell purity of water by visual appearance. Purification Of Water

3. Purification of is done by TWO ways: 1. Natural Methods 2. Artificial Methods Purification Of Water

4. Natural Method includes:- Aeration Sedimentation Sunlight Dilution Oxidation Plants & Animals (Aquatic) 1. NATURAL METHODS

5. They may be carried out at : A . Purification of Water on Large Scale B . Purification of Water on Small Scale 2. Artificial Methods

6. BOILING : for 5-10 minutes kills almost all organisms & removes temporary Hardness. DISTILLATION: not commonly used due to higher cost, used in Labs. Etc. ADDITION OF CHEMICALS Bleaching Powder : 5% solution is used Dose: 3-6 drops/L contact time of ½ hour. Chlorine Tablets/ Halazone Tablets. One tablet/litre. Iodine Solution: 02 drops of 2% Soln./litre KMnO4: an amount that gives just pink coloration to the Water. Alum : used for turbid water in a dose of 0.1-0.4 grains/5 litres of Water. A. PURIFICATION ON SMALL SCALE

7. Coagulation Sedimentation Filtration Disinfection Storage B. Purification of Water on Large Scale

8. Depending on the type of treatment plant and the quality of raw water, treatment generally proceeds in the following sequence of stages : 1. SCREENING 2. AERATION 3 . PH CORRECTION 4. COAGULATION AND FLOCCULATION 5 . SEDIMENTATION 6. PRE-CHLORINATION AND DECHLORINATION 7 . FILTRATION 8 . DISINFECTION 9 . PH ADJUSTMENT WATER TREATMENT PLANT STAGES

9. 1. SCREENING - REMOVAL OF ANY COARSE FLOATING OBJECTS, WEEDS, ETC. 2. AERATION - DISSOLVING OXYGEN INTO THE WATER • REMOVES SMELL AND TASTE • PROMOTES HELPFUL BACTERIA GROWTH • PRECIPITATES NUISANCE METALS LIKE IRON AND MANGANESE . 3 . PH CORRECTION - PREPARING FOR COAGULATION AND TO HELP PRECIPITATE METALS. (MAKE WATER ACIDIC TO LEACH OUT METALS) INITIAL STAGES

10. 4. COAGULATION AND FLOCCULATION – ADD COAGULATING AGENT (ALUMINUM SULFATE OR IRON SULFATE) - CAUSES AGGLOMERATION (CLUMPING) AND SEDIMENTATION OF SOLID PARTICLES -THESE SOLID PARTICLES ARE CALLED FLOC OR SLUDGE

11. 5. SEDIMENTATION – FLOC SETTLES OUT AND IS SCRAPED AND VACUUMED OFF THE BOTTOM OF LARGE SEDIMENTATION TANKS. CLARIFIED WATER DRAINS OUT OF THE TOP OF THESE TANKS IN A GIANT DECANTING PROCESS. 6 . PRE-CHLORINATION AND DECHLORINATION - MOSTLY TO KILL ALGAE THAT WOULD OTHERWISE GROW AND CLOG THE WATER FILTERS .

12. 7. FILTRATION (DEPENDS ON SIZE OF . PLANT/VOLUME OF WATER CONSIDERATIONS ) • RAPID-SAND FILTERS FORCE WATER THROUGH A 0.45-1M LAYER OF SAND AND WORK FASTER, NEEDING A SMALLER AREA. BUT THEY NEED FREQUENT BACK-WASHING • SLOW-SAND FILTERS REQUIRE A MUCH LARGER AREA BUT REDUCE BACTERIOLOGICAL AND VIRAL LEVELS TO BETTER DUE TO THE SCHMUTZDECKE (BIOFILM) LAYER. THE TOP 1 INCH OF BIOFILM MUST BE PERIODICALLY SCRAPED OFF AND THE FILTER OCCASIONALLY BACK-WASHED

13. 8. DISINFECTION - WATER COMPLETELY FREE OF SUSPENDED SEDIMENT IS TREATED WITH A POWERFUL OXIDIZING AGENT USUALLY ONE OF THREE TYPES: • CHLORINE : CHLORINE CAN FORM HARMFUL BYPRODUCTS AND HAS SUSPECTED LINKS TO STOMACH CANCER AND MISCARRIAGES. • CHLORAMINE (CHLORINE THEN AMMONIA) : ANY AGENCIES NOW RESIDUALLY DISINFECT WITH CHLORAMINE- DOES NOT DISSIPATE FROM WATER BEFORE REACHING CONSUMERS LIKE CHLORINE DOES • OZONE- MORE EXPENSIVE • UV-LIGHT 9 . PH ADJUSTMENT - SO THAT TREATED WATER LEAVES THE PLANT IN THE DESIRED RANGE OF 6.5 TO 8.5 PH UNITS. FINAL TOUCHES