AWWA WQTC69436

A monochloramine microelectrode with a tip size between 5 and 15 1/4 m and using platinum wire was successfully designed, fabricated and characterized for in-situ monochloramine measurement within chloraminated distribution system biofilm. The monochloramine microelectrode showed sensitivity toward monochloramine concentrations (0.54 to 16.1 mg Cl₂/L) at an applied potential of +550 mV (Ag/AgCl reference electrode) at pH 8.0 and 23ºC. The monochloramine microelectrode has successfully measured monochloramine microprofiles with high spatial resolution (50 µm) without biofilm structure disruption during measurements. Ultimately, this research will lead to a better understanding of the monochloramine microelectrode for in situ application within a chloraminated drinking water system biofilm; and, along with other microelectrodes (e.g., ammonia, pH, DO) under development, elucidate the nitrification phenomena occurring in the biofilm. Includes 10 references, figures.