The correct answer is option 2. 5 NTU.
Turbidity in water refers to the cloudiness or haziness caused by the presence of suspended particles, such as sediment, silt, and organic matter. The measurement of turbidity is expressed in Nephelometric Turbidity Units (NTU). The Bureau of Indian Standards (BIS) has established standards for various parameters in potable water, including turbidity.
In the context of BIS IS-10500:2012, which outlines the standards for drinking water in India, the maximum permissible limit of turbidity is set at 5 NTU. This means that the water intended for human consumption should not exceed this level of turbidity. The rationale behind this limit is to ensure that the water is clear and free from excessive suspended particles, as high turbidity may affect the aesthetic quality of water and indicate the presence of impurities.
The use of Nephelometric Turbidity Units (NTU) as a measurement unit implies that the turbidity is determined by measuring the scattered light in a specific angle (usually 90 degrees) to the incident light. This method provides a standardized and reproducible measurement of turbidity.
Regular monitoring and adherence to turbidity standards are essential to guarantee the safety and quality of drinking water. Water treatment processes, such as sedimentation and filtration, are often employed to reduce turbidity and remove suspended particles, ensuring that the water meets the established standards for potable water consumption. |
