ORP is a frequently used term in the water treatment and food processing industry. ORP means ”Oxidation Reduction Potential OR. So what is this? The ORP can best be defined as follows; ORP is a measure of the ability to clean water and to break down contaminants. It is measured in mV (millivolt) from -2000 to +2000 measuring range. Since ozone is also an oxidant, it is the positive ORP levels (above 0 mV) that we need to address.
ORP sensors work by measuring dissolved oxygen levels. The higher the level of oxygen in water, the lower the oxygen level because the organics in the water consume oxygen and the low ORP level is observed. The higher the ORP level, the better the ability to remove microbes or carbon-based contaminants in the water. The left column of the table below defines ORP levels for various applications.
The ORP level can also be used to monitor bacterial activity in water because there is a direct link between the ORP level in the water and the Coliform count.