Save Money, Time and Water with this Free Chlorine Measurement Approach

 Water plant professionals know that when it comes to measuring free chlorine, amperometric technology has many advantages – and one significant disadvantage. The measurement is pH dependent. As a result of this disadvantage, many plant managers find themselves balancing the pros and cons of amperometric versus colorimetric technologies and sometimes finding themselves with no ideal choice.

In a recent article in WaterWorld, Michael Francis, global product manager, Emerson, discussed this critical choice. In the article he examines the nature of free chlorine measurement and why it is inherently pH dependent. He then goes on to analyze the benefits and disadvantages of colorimetric and amperometric measurement methods. Colorimetric systems require expensive reagents that can cost between $750 and 1,000 a year per system. Since most water authorities have hundreds of systems, the dollars really add up in direct costs, and especially, in personnel time.

Michael discusses the significant benefits of reagentless amperometric technology, and then reviews the typical ways that water plants have dealt with the need for pH measurement, most often requiring the use of an auxiliary pH analyzer. These systems need complex integration and require a large flow sample which overuses water and raises ongoing costs.

Ultimately, Michael outlines an elegant solution that allows water plants to take full advantage of the benefits of amperometric measurement with very few downsides. An integrated approach saves water plants money, time and water. Check out the complete article HERE.

How do you measure free chlorine?