deflouridation technique

Welcome

Never stop listening :

More awesome content here...

The Nalgonda defluoridation technique, also known as the Nalgonda technique, is a simple and cost-effective method for reducing excessive fluoride levels in drinking water. It is named after the region of Nalgonda in the Indian state of Telangana, where it was first implemented in the 1980s to combat the issue of high fluoride content in groundwater.

Excessive fluoride in drinking water can lead to dental and skeletal fluorosis, which are serious health concerns. The Nalgonda defluoridation technique aims to bring the fluoride levels within the permissible limits set by the World Health Organization (WHO) and other regulatory bodies.

The process involves the use of locally available materials, primarily alum (aluminum sulfate) and lime (calcium hydroxide). Here's how the Nalgonda defluoridation technique works:

1. Coagulation: Alum is added to the water to initiate coagulation. Alum reacts with fluoride ions present in the water, forming aluminum fluoride complexes.

2. Flocculation: After coagulation, the water is gently stirred to promote the formation of flocs, which are larger particles that contain the aluminum fluoride complexes.

3. Sedimentation: The water is allowed to settle, and the flocs gradually settle at the bottom of the container.

4. Filtration: The settled water is then passed through a simple sand filter to remove any remaining suspended particles and flocs.

5. pH Adjustment: Lime is added to the filtered water to raise its pH. This step helps to convert the aluminum fluoride complexes into aluminum hydroxide, which has a lower solubility. The aluminum hydroxide then precipitates out along with the fluoride ions.

6. Final Filtration: The water is passed through another sand filter to remove the precipitated aluminum hydroxide and any other remaining impurities.

The Nalgonda defluoridation technique effectively reduces fluoride levels to safe limits, making the water suitable for consumption. It is a low-cost and simple method that can be implemented in areas with limited resources and infrastructure. The technique has been successfully applied in various regions facing fluoride contamination in their water sources, contributing to improved public health by mitigating the risks associated with excessive fluoride intake.

Nalgonda Defluoridation Technique MCQs

1. Q1. The Nalgonda defluoridation technique is used to:

   a) Increase fluoride levels in drinking water
   b) Reduce fluoride levels in drinking water
   c) Add alum to drinking water
   d) Filter suspended particles in drinking water
   

2. Q2. Excessive fluoride in drinking water can lead to:

   a) Dental fluorosis
   b) Vitamin deficiency
   c) Iron toxicity
   d) Skin rashes
   

3. Q3. What locally available material is used for coagulation in the Nalgonda technique?

   a) Chlorine
   b) Alum
   c) Lime
   d) Sodium fluoride
   

4. Q4. What is the purpose of coagulation in the Nalgonda defluoridation technique?

   a) Remove suspended particles
   b) Raise pH of water
   c) Reduce fluoride levels
   d) Increase fluoride levels
   

5. Q5. What are the larger particles formed during flocculation?

   a) Aluminum fluoride complexes
   b) Fluoride ions
   c) Calcium hydroxide
   d) Flocs
   

6. Q6. What step involves gently stirring the water to promote the formation of flocs?

   a) Coagulation
   b) Filtration
   c) Sedimentation
   d) Flocculation
   

7. Q7. What does the pH adjustment step involve in the Nalgonda technique?

   a) Adding fluoride to water
   b) Adding alum to water
   c) Adding lime to water
   d) Adding chlorine to water
   

8. Q8. The Nalgonda defluoridation technique aims to:

   a) Raise fluoride levels in drinking water
   b) Remove excess fluoride from drinking water
   c) Disinfect drinking water
   d) Lower pH of drinking water
   

9. Q9. What is the purpose of final filtration in the Nalgonda technique?

   a) Remove fluoride ions
   b) Remove suspended particles and flocs
   c) Raise the pH of water
   d) Lower the pH of water
   

10. Q10. The Nalgonda defluoridation technique is primarily used to address health issues related to:

    a) High iron content in water
    b) High fluoride content in water
    c) High chlorine content in water
    d) High pH of water