What is the Difference Between NTU and FTU?

The key difference between NTU (Nephelometric Turbidity Unit) and FTU (Formazin Turbidity Unit) is the method of measurement and the type of light used for determination. Both units measure turbidity, which is the cloudiness of a liquid sample caused by suspended particles. However, they use different methods to determine the turbidity values:

• NTU: NTU measurement uses white light for determination. It signifies that the instrument is measuring scattered light from the sample at a 90-degree angle.
• FTU: FTU uses infrared light for determination. It is based on the use of Formazine, a chemical compound that produces a known amount of turbidity when added to water.

Despite the differences in measurement methods, NTU, FTU, and another unit called FAU (Formazin Attenuation Unit) are essentially the same in value. The choice of unit depends on the specific method or instrument used to measure turbidity. In some cases, NTU and FTU can be used interchangeably. Turbidity measurement is essential in various applications, such as water treatment and environmental monitoring, to ensure water quality and safety.

Comparative Table: NTU vs FTU

The key difference between NTU and FTU is the type of light used for determination. NTU (Nephelometric Turbidity Unit) measurement uses white light, while FTU (Formazine Turbidity Unit) uses infrared light. Both units are used to measure the turbidity of a liquid sample, which is the cloudiness caused by suspended particles. Here is a table comparing the two units:

Both NTU and FTU are used to measure turbidity, but they use different methods and light sources. NTU is more commonly used in water treatment applications, while FTU is less commonly mentioned in this context.