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The role of oxidation-reduction potential (ORP). in determining quality of water

The electrical potential needed for the reduction or slowing down of the oxidation process is called oxidation-reduction potential (ORP).

Water must have a negative ORP in order for it to be fit for drinking.

The amount of oxygen and other similar elements dissolved in the water determines the ORP of the water. It is measured in terms of millivolts (mV).

What is oxidation-reduction potential (ORP)?

The oxidation-reduction potential is the electrical potential necessary for the reduction of oxidation.

This process is referred to as deoxidisation.

ORP determines the reduction capacity to attract active oxygen and is related to pH levels. With the increase in pH, ORP also surges.

It can be increased by making use of certain electrodes. It is a pocket-friendly measure which helps to analyse a lot of processes.

People make use of various ORP testing equipment to monitor the quality of water for the long term.

Characteristics of ORP

  • ORP reading is vital to determine the contamination level of the water in accordance with its reduction and oxidation ability.
  • An ORP sensor is a combination of a sensor, a reference electrode and a measuring electrode.
  • If the ORP reading is high, it implies that the solution is more oxidising, and if the reading is low, it implies the sample solution is more anti-oxidising.
  • The output of an ORP sensor, information about the dominating element in the sample solution, temperature and pH of the solution helps in predicting whether any chemical reaction will occur or not and what will be the oxidation state of ions present in the solution.

The ORP of natural water is affected by its temperature, and it is quite tedious to work out a relevant relation between ORP and temperature practically because the components of natural water are not known.

At the time the ORP electrodes may get dirty, as a result, the reading of which the readings may differ.

Thus, it is imperative to keep the surface of the electrodes neat and clean. If the same solution is measured by making use of two ORP sensors, it is quite possible to have different kinds of readings.

The contamination in the sample solution also causes variations in the readings.

The ORP value of rainwater, tap water and bottled water is positive, and it is considered an excellent oxidising agent.

However, alkaline ionised water is anti-oxidising in nature because its ORP value is negative. This value is equally important as the pH value to analyse the quality of water.

Benefits of ORP

  • Oxidation-reduction potential water quality is vital to know whether the water is fit for drinking or not.
  • This approach is useful for monitoring disinfection due to chlorine in the swimming pool, applications for water analysis, cooling towers and many more.
  • Life of bacteria in the water is also affected by the ORP level. This approach is frequently applied in the water treatment process for removal of contaminants.

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