The analysis of chlorine dioxide and its oxychlorine by products in water is a difficult topic due to the volatility of chlorine dioxide and to the interferences from other species with standard test methods. In the real samples, this is further complicated as chlorine dioxide is often used in a system which is dynamic and therefore sampling is also important.
The USEPA require that both chlorine dioxide (ClO2) and chlorite (ClO2–) are monitored daily at the start of a distribution network and that chlorite is measured less frequently at various points throughout a network. Chlorate is not required, although is included under the Information Collection Rule.
The following are methods that have been approved by the USEPA for ClO2 monitoring:
As DPD has been removed as a standard method for determining ClO2 by the AWWA Standard Methods committee, the EPA will also probably remove it sooner rather than later. As for chlorite, there are a few methods (such as ion chromatography) approved for chlorite monitoring. None of them are truly portable as the ChlordioX Plus is making it the only portable USEPA approved method for determining chlorite.
Other colorimetric methods are available however none are approved for compliance testing.
This summary of methods is based on White’s Handbook of Chlorination and Alternative Disinfectants by the Black and Veatch Corporation, published by Wiley in 2010.
See here for a list of EPA methods approved for chlorine dioxide and chlorite monitoring under the alternative test methods program.
26th June 2020
In this series of webinars, we discuss how Kemio Disinfection is used to advance disinfectant analysis and validation in different food and beverage applications.
5th June 2020
In this article we take a look at lead contamination cases, what caused contamination, assess the risks associated with lead contamination and what you can do to prevent people from drinking contaminated water
28th May 2020
We are delighted to be offering a range of webinars to help you learn more about water safety and how to improve your water testing procedures. Our webinars will cover a range of topics including water chemistry, application-focused testing and product training. Click here to view the full webinar schedule for June 2020.