NALGONDA TECHNIQUE in flouridesde flouridation pptx

dental

1. GOOD MORNING

2. DR. K.YADAV RAO DEPARTMENT OF PREVENTIVE AND COMMUNITY DENTISTRY OXFORD DENTAL COLLEGE, HOSPITAL AND RESEARCH CENTRE. NALGONDA TECHNIQUE

3. LESSON PLAN TARGET POPULATION– III rd BDS STUDENTS ALLOTED TIME ---------10 minutes OBJECTIVES OF PEDAGOGY Knowing the defluoridation method by Nalgonda technique. AID USED –CHALK AND BOARD, AUDIO VISUAL AID: LCD PROJECTER. METHOD OF EVALUATION- QUESTIONS AT THE END.

4. Contents Introduction Definition of defluoridation Methods of defluoridation Nalgonda technique of defluoridation -Domestic defluoridation -Community level defluoridation Salient features of Nalgonda technique Indications for adopting Nalgonda technique. Summary conclusion References

5. Introduction In our country, the states having fluoride levels (endemic fluoride belts with fluoride content in water more than 4.00ppm) are Punjab, Haryana, Rajasthan, Gujarath , Madhya Pradesh, Andhra Pradesh, Tamilnadu etc. In Andhra Pradesh, Ananthapur , Karimnagar and Krishna districts have a fluoride content of more than 5.0ppm and Nalgonda, Kurnool, Hyderabad have a fluoride content ranging from 1.5- 5.0 ppm .

6. Chalkiness of teeth Brown stain on teeth Brown wavy striations on teeth Severe mottling

7. There are some villages in western India, like Gulabpur -9.5, Phagi-8.5, Chirava - 8.5, and Sgalia - 19.0ppm fluoride in the water. Safe drinking water is the primary need of every human being. Village population mainly depends upon ground water sources. All ground water sources are not always safe. Some of these have problems such as excess salinity, iron, manganese, nitrate and fluoride.

8. Definition The downward adjustment of level of fluoride in drinking water to optimal level of 1ppm.

9. Methods of defluoridation Defluoridation can be done by two methods :

10. NALGONDA TECHNIQUE Water can be purified at - Domestic Community level

11. Mechanism of defluoridation The Nalgonda technique involves the addition of two readily available chemicals. The process comprises addition in sequence of sodium aluminate or lime, bleaching powder and filter alum to the fluoride water followed by rapid mixing, flocculation, sedimentation and filtration.

12. Lime + Bleaching powder + Filter Alum Rapid mixing Flocculation Sedimentation Filtration

13. Rapid mixing Rapid mixing is an operation by which the coagulant is rapidly and uniformly dispersed. Results in proper utilization of chemical coagulant, preventing localization of concentration.

14. Flocculation This is second stage of the formation of settable particles from destabilized colloidal sized particles and is achieved by gentle and prolonged mixing.

15. Sedimentation It is the separation from the water by gravitational setting of suspended particles that are heavier than water Filtration Filtration is a process for separating suspended and colloidal impurities from water by passage through porous media.

16. Domestic level A container of 20-50 litres capacity is suitable for this purpose. A tap 3-5cm above the bottom of the container is use full to withdraw treated water. Adequate amount of lime water (30mg/ litre of water) and bleaching powder are added to the water first and mixed well with it. Alum solution (500mg/ litre of water) is then poured and water is stirred for 10 minutes.

17. Later the contents are stirred for one hour and will be followed by flocculation, sedimentation and filtration. Water is allowed to settle down for 1hour. The clear water is drawn through filtration without disturbing the sediment.

18. Fill and draw type defluoridation plant for small community For communities with a population ranging from 200-2000, a defluoridation plant of fill and draw type is recommended. The plant consist of a hopper-bottom cylindrical tank with a depth of 2m. The diameter depends upon the quantity of water to be treated. It has a stirring mechanism which can be either hand operated or power driven.

19. Raw water is pumped to the unit and required quantity of lime , bleaching powder and alum are added. Contents are stirred for 10 min and then followed by rapid mixing , flocculation , sedimentation and filtration. In this procedure, pump with adequate capacity the entire operation can be completed in about four hours time and atleast three batches of defluoridated water can be obtained in a day.

20. Salient features of Nalgonda technique No handling of caustic acids and alkalies Readily available chemicals used in conventional municipal water treatment are only required. Adaptable to domestic use Simplicity of design, construction, operation and maintenance. Little wastage of water and least disposal problem Needs minimum of mechanical and electrical equipment. No energy except for muscle power for domestic equipment.

21. Indications for adopting Nalgonda technique Absence of acceptable, alternate low fluoride source within transportable distance. Raw water fluoride ranging from 1.5mg to 20mg F/L.

22. conclusion Nalgonda technique is a simple and economical process which can be adapted by a common man. It can be adopted at domestic and community level.

23. References Soben peter Essentials of preventive and community dentistry 3 rd edition. Amrit Tewari fluorides and dental caries A Compendium. Journal of the Indian Dental Association. S.S. Hiremath Textbook of Preventive and Community Dentistry.

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