What is a common method for measuring turbidity in water?

Nephelometric turbidity testing is the most common method used to measure turbidity in water because it provides a reliable assessment of water clarity. This process involves using a nephelometer, which emits a light source and measures the amount of light scattered by particles suspended in the water. The scattering of light occurs when these particles interfere with the path of the light beam, and the turbidity level is quantified based on the intensity of the scattered light, typically expressed in Nephelometric Turbidity Units (NTU).

This method is preferred in water treatment because it can detect a wide range of turbidity levels with high sensitivity and is quick to perform. Other methods, like gravimetric analysis, involve filtering water samples to weigh particles, which is more time-consuming and less practical for routine monitoring. pH testing and conductivity testing are useful for assessing different water quality parameters but are not indicators of turbidity, as they measure chemical characteristics rather than the physical presence of particles in suspension. Thus, nephelometric turbidity testing stands out as the most effective technique for evaluating water clarity in treatment processes.