Free Chlorine Monitoring as Water Data Infrastructure for Circular Water Systems

A new Viewpoint by Hao Zhang, Founder and Director of Technology at OneStep Technologies, has been published in ACS ES&T Water as part of the cross-journal Special Issue, "Circular Water Economy," spanning six ACS journals.

The article explores why online free chlorine monitoring should be viewed not only as an analytical measurement, but also as part of the data infrastructure of modern water systems.

As water systems become increasingly digital and automated, the focus extends beyond measurement frequency to producing trustworthy, decision-ready data that support treatment verification and operational decisions.

The Viewpoint highlights analytical validity, field reliability, and data continuity as connected requirements for the next generation of online chlorine monitoring.

This perspective is particularly relevant to water reuse and decentralized treatment, with broader relevance to advanced water treatment and desalination.