What range of Oxidation-Reduction Potential (ORP) is considered low?

The range of Oxidation-Reduction Potential (ORP) that is considered low is indeed 0 to 200 millivolts (mV). ORP is an important measurement in wastewater treatment as it reflects the ability of a solution to either gain or lose electrons, which is crucial for assessing the oxidative or reductive state of wastewater. A lower ORP indicates a more reducing environment, which can be prevalent in anaerobic conditions where microbial processes are dominant.

A range of 0 to 200 mV signifies that there is a higher likelihood of promoting anaerobic conditions, which are essential in certain stages of wastewater treatment, such as in anaerobic digesters. In this environment, organic matter is broken down by bacteria, producing biogas as a byproduct. Therefore, understanding and monitoring ORP can help operators optimize the biological processes involved in wastewater treatment.

The other ranges of ORP indicate increasing levels of oxidative potential, which may correspond to different treatment conditions or stages that require different management strategies.