Development of an on-line chlorine sensor for water quality monitoring in public distribution networks

A new on-line free chlorine sensor based on a microdisc electrode array is presented. The sensor is microfabricated using microelectronic-based processes. Sensor characteristics include a good linearity in the 0-1 mg/l range, a sensitivity of 13 nA/(mgCl₂/l) with a detection limit of 0.02 mg/l of free chlorine. The sensor response has a low pH and flow dependence. A very good stability over 4 weeks of continuous use in drinking water is demonstrated. Mounted on an automatic control valve the sensor will offer the possibility to monitor and control the water quality in a distribution network.