ANS:A - disinfection and control of taste & odour.

The correct answer is: disinfection and control of taste & odour.

Explanation:

Chloramines are used in water treatment primarily for disinfection purposes and to help control taste and odor in drinking water. They are a more stable alternative to chlorine, providing longer-lasting disinfection effects while minimizing the formation of harmful disinfection byproducts.

Explanation of "Disinfection and Control of Taste & Odour"

Disinfection and control of taste and odor are critical functions in water treatment processes, and chloramines play a significant role in achieving these objectives.

1. Disinfection

• Microbial Reduction: Chloramines effectively kill or inactivate a wide range of harmful microorganisms, including bacteria, viruses, and protozoa, ensuring the safety of drinking water.
• Residual Effect: Unlike chlorine, chloramines provide a longer-lasting residual effect in the water distribution system, maintaining disinfection over time and distance.
• Lower Byproduct Formation: Using chloramines instead of chlorine reduces the formation of harmful disinfection byproducts (DBPs), such as trihalomethanes (THMs), which can occur with chlorine use.

2. Control of Taste & Odour

• Taste and Odor Management: Chloramines help mitigate unpleasant tastes and odors in water, often caused by organic materials, algae, or other contaminants.
• Stability in Distribution Systems: Chloramines remain stable in the water distribution system, preventing the development of taste and odor issues that can arise from biological growth or chemical reactions in the water supply.

Summary

Chloramines are essential in water treatment for disinfection, effectively controlling harmful microorganisms while providing a long-lasting residual effect. Additionally, they help control taste and odor, ensuring the water remains palatable and free from unpleasant flavors or smells throughout the distribution system.