Water treatment process

water treatment process under the sunbject of ITP (Infrastructure and transportation planning)

1. G raduate Report Presentation on “ Water Treatment Process ” ME – TCP, Year – I, Semester – I Under the subject of ITP (Subject Code : 3714802) SARVAJANIK COLLEGE OF ENGINEERING & TECHNOLOGY, SURAT FACULTY OF CIVIL ENGINEERING MASTER OF ENGINEERING (TOWN AND COUNTRY PLANNING) Affiliated with GUJARAT TECHNOLOGICAL UNIVERSITY

2. Introduction Why it is needed? To kill all pathogenic germs, which are harmful to human health To remove the unpleasant and objectionable taste and odours from the water To remove dissolved gases ,colour of water To make water fit for domestic, industrial, and commercial uses. To remove micro organism and colloidal matters 3

3. Raw water collection 3 / 28 / 17 water treatment 4

4. Initial Stages Screening - the removal of any floating objects like leaves, branches, fishes , weeds, etc. from the water. Bar Screening

5. 3 / 28 / 17 water treatment 6 Mechanical Screening

6. 3 / 28 / 17 w ate r t r e a tm e nt 8 Aeration – Dissolving oxygen into the water to remove smell and taste, promote helpful bacteria to grow, and precipitate nuisance metals like iron and manganese .

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8. 03/28/17 water treat m e nt 10 Spray aerators

9. 3 / 28 / 17 w ate r t r e a tm e nt 7 Sedimentation: Removal of Suspended matters having higher specific gravity than water and also fine suspended matter.

10. Major Clean Up • Coagulation and flocculation - causes the agglomeration and sedimentation of suspended solid particles through the addition of a coagulating agent (usually aluminum sulfate and/or iron sulfate) to the raw water along with a polymer to help form a floc. • Filtration - Remove Micro-organism and colloidal matter • Disinfection ---Pre-chlorination and dechlorination - mostly to kill algae that would otherwise grow and clog the water filters. Also kills much of the remaining unprotected bacteria. • Softening - To remove hardness

11. 14 Theory of coagulation  Coagulation is the destabilization of colloids by addition of chemicals that neutralize the negative charges The chemicals are known as coagulants Coagulation is essentially a chemical process

12. Mixing device 3 / 28 / 17 w ate r t r e a tm e nt 20 Mixing basins with baffle walls Mixing basin with mechanical devices (Rapid mixing)

13. water treatment • Rapid or Flash mixing is the process by which a coagulant is rapidly and uniformly dispersed through the mass of water. This process usually occurs in a small basin immediately preceding or at the head of the coagulation basin. Generally, the detention period is 30 to 60 seconds and the head loss is 20 to 60 cms of water. Here colloids are destabilized and the nucleus for the floc is formed.  Slow mixing brings the contacts between the finely divided destabilised matter formed during rapid mixing.

14. Coagulation aim water treatment

15. What is Flocculation? Flocculation is the agglomeration of destabilized particles into a large size particles known as flocs which can be effectively removed by sedimentation or flotation.

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18. water treatment Hydraulic Flocculation Plan view (horizontal flow) Vertically baffled tank L Isometric View (vertical flow) L W H Horizontally baffled tank The water flows horizontally. The baffle walls help to create t u r b ul e n c e a nd th u s f ac i l it a t e mixing The water flows vertically. The baffle walls help to create turbulence and thus facilitate mixing

19. Hydraulic flocculators water treatment

20. water treatment Hydraulic flocculators: simple technology

21. C l arif i e r • Af t e r F lo cc ul a t i o n W at e r e nt e rs t h e se t t ling t an k w h i c h is commonly called Clarifier. Clariflocculator In m o de rn p r ac t i ce , f l oc c u l a t o r a nd c la r i fi e r a r e w h i c h p r ov i de d chamber in on e u n it c all e d C l a ri f l occ ul a t o r i n is provided in the center and clarifier compartment is formed by the periferical space. water treatment

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24. Fi l trat i o n water treatment T he p ro ces s o f p a ss i n g t h e w at e r t h r ou gh t h e b ed of s u c h granular materials is known as filtration. Types of filter 1- The slow sand gravity filter 2- Rapid sand filter

25. Slow sand filters are used in water purification for treating raw water to produce a potable product. They are typically 1 to 2 metres deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water. Periodically clean by removing, cleaning and replacing the upper few inches of biologically active sand . water treatment

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27. Rapid sand filters 3 / 28 / 17 water treatment 42 Rapid sand filtration is a purely physical drinking water purification method. Rapid sand filters (RSF) provide rapid and efficient removal of relatively large suspended particles . Two types of RSF are typically used: Rapid gravity Rapid pressure sand filters

28. 3 / 28 / 17 water treatment 43 The biggest disadvantages of slow sand filter is that it requires large area due to slow filtration rate . This Requirement make it uneconomical for places where land is very costly in urban area. In order to reduce requirement of space and to increase the rate of filtration , a lot of research conducted which finally led to the developed of rapid sand filter.

29. 3 / 28 / 17 water treatment 44 R ap id sa nd f il t er s hav e f ilter r a t e s 4 t i m es th os e of s l o w sand filters. The major parts of a rapid sand filter are: Filter tank or filter box Filter sand or mixed-media Gravel support bed Under drain system Wash water troughs Filter bed agitators

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31. PRESSURE FILTERS Pressure filters are used extensively in iron and manganese removal plants. A pressure sand filter is contained under pressure in a steel tank, which may be vertical or horizontal, depending on the space available. As with gravity filters, the media is usually sand or a combination of media, and filtration rates are similar to gravity filters. Groundwater is first aerated to oxidize the iron or manganese, and then pumped through the filter to remove the suspended material. 03/28/17 water treatment 46

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