NTU stands for Nephelometric Turbidity unit, i.e. the unit used to measure the turbidity of a fluid or the presence of suspended particles in water. The higher the concentration of suspended solids in the water is, the dirtier it looks and the higher the turbidity is.
NTU units are most commonly used by purification plants. We rather use suspended solids (SS) measured in mg/l or ppm because we mainly operate on the wastewater treatment plant market, but there is a relation between suspended solids and NTU..
The relation between NTU and suspended solids is as follows: 1 mg/l (ppm) is equivalent to 3 NTU. For example, 300 mg/l (ppm) of SS are 900 NTU.
According to the World Health Organization, the turbidity of drinking water should never exceed 5 NTU