Water treaters will learn that there is not a best way of using ClO2; that the best method of application depends entirely on the cooling system being treated.

• How ClO2 has been fed historically, with case histories.
• System design issues that impact the method of ClO2 application, with case histories.
• Unusual cooling system conditions and how they impact feed of ClO2, with case histories.

Greg Simpson.

ClO2 has been used in cooling towers for a half-century.  Since ClO2 must be made on-site and applied immediately, the method of application varies with the ClO2 generation design, as well as the end-use application.  As cooling system and ClO2 generator designs have changed, the method of application has changed.  In the early years the common approach was to apply 5 ppm based on system volume.  And this dosage was the same whether the system was clean or contaminated. 

In the late 1980s, a more systematic approach was developed, whereby ClO2 was applied very successfully to pump suction at about 1 ppm multiple times per day for short durations.  This approach was used for years.  The problem with this is that it did not distinguish between a clean and dirty system either. 

Finally, an approach was developed whereby the feed of ClO2 could automatically respond to leaks or changes in the quality of the makeup water.

More recently some have used a very low dosage of ClO2, fed continuously.

This paper presents pros and cons of each type of treatment. 

Greg D. Simpson has consulted globally on a variety of issues to a variety of industries, including petroleum refining, oil field, aerospace, medical waste sterilization, ballast water, pharmaceutical, chemical, pulp and paper, electronics and semiconductor manufacturing, municipal treatment, environmental, food, and others.  

A scientist at a top-secret nuclear weapons facility in his early career, since 1980 Greg has been involved in the water treatment industry serving in a variety of roles.

He has authored and / or presented well over 100 technical papers. He has written three books about chlorine dioxide and was a major contributor to a fourth.