Is ORP Really Your Best Option For Dechlorination Measurement?

The correlation between chlorine concentration and ORP (oxidation-reduction potential) sensors can be affected by various factors. ORP sensors respond quickly to an increase in oxidants, but they respond slowly to overfeeding of the reducing agent or restoring chlorine absence. This makes it difficult to accurately measure low levels of chlorine using ORP measurements alone.

Overfeeding dechlorinating agents based on ORP measurements can lead to an anaerobic environment and promote bacterial growth, causing biofouling on RO membrane surfaces. Moreover, ORP measurements cannot ensure chlorine residuals at a parts-per-billion level, which is necessary for disinfection without damaging membranes.

Relying solely on ORP measurements for dechlorination decisions can lead to misinterpretations and inaccurate results. Alternative methods, such as colorimetric analysis, should be used when necessary to ensure accurate and reliable measurements.