Knowledge centre

Chlorine dioxide

Chlorine dioxide | Significance

Chlorine dioxide is a compound between chloride (Cl) and oxygen (O2). This type of chlorine is widely used as a bleaching agent and a disinfectant. This is because its disinfecting effect is already very effective even at low concentrations.

Unlike chlorine, this agent is explosive. Therefore, it is forbidden to transport chlorine dioxide and is often created "on site".

Chlorine dioxide | Chemical formula

The chemical formula for chlorine is: Cl.

Chlorine dioxide | Measurement

Chlorine dioxide, due to its disinfectant work, is thus often used for drinking water cleaning, cooling water cleaning, food processing and also protects water pipes and still water from the development of legionella bacteria. As with (free) chlorine, there is also a correlation between the pH value and the disinfecting effect. Whereas with (free) chlorine the pH value should be between 7.2 and 7.4 for optimal disinfection, this is different with chlorine dioxide. In contrast to (free) chlorine, the higher the pH value, the better the degree of disinfection.

In addition, the temperature of the water also plays a role. This is because at lower temperatures, solubility in water becomes higher.

In short, besides measuring chlorine dioxide, measuring the pH value and temperature in the water is therefore also very important. That is why the most reliable systems not only measure the concentration in the water, but often go together with a pH sensor. The measurement of chlorine dioxide in water is done by measuring in mg/l (milligrams per litre) or ppm (parts per million).

Chlorine dioxide is often used to treat cooling water

Chlorine dioxide | Increase / Decrease value

To determine the value in the water, automatic water treatment systems are often used which, on the one hand, measure the level in the water and automatically adjust doses of chlorine dioxide accordingly.

Chlorine dioxide | Applications

Chlorine dioxide has strong disinfectant properties. Partly because of this property, it is used to treat water in the following sectors:

  • Drinking water treatment;
  • Wastewater treatment;
  • Treatment of industrial process water;
  • Disinfection of cooling tower water;
  • Legionella treatment in water pipes;
  • Products and food handling.

Disinfection of tap water is one of the uses of chlorine

Chlorine dioxide | dosing pumps and systems

Within Emec's product range, we offer various solutions for chlorine dioxide dosing. We also offer a number of turnkey packages with dosing pumps incl. sensors. 

A complete solution? 

At Emec Webshop, we also offer a total solution with for dosing. With this solution, chlorine dioxide is produced "on site" and dosed based on the measurements of the connected ORP and pH sensor. Please note that this is not permitted in all countries.

Sensors and controllers for chlorine dioxide dosing

As described earlier, there are a number of values that ensure that the disinfecting property of chlorine dioxide is perfect, namely:

  • ORP / Redox value, which measures the degree of disinfection;
  • pH value, or the acidity of water. A high pH value can improve the disinfecting effect of;
  • Temperature. At low temperatures of water, it is better absorbed.

We offer a number of electrodes for all these values. Connected to a controller (Emec Centurio) or directly to the dosing pump, the system can then automatically control the ORP, temperature and pH value in the water. In addition, we also offer a free chlorine sensor (Emec SCL2). For more information about this sensor or its purchase, please contact us.