Analyze Free Ammonia Before It's Too Late

This article discusses a study done by the Washington Aqueduct, Washington, D.C. at the request of the U.S. Environmental Protection Agency (USEPA) to study its chloramination practices for minimizing the amount of free ammonia in the distribution system. One objective of the study was to determine a viable holding time window for the analysis of free ammonia in which the free ammonia level would not significantly increase from that at the time of sample collection. Previous practices are discussed, along with the field study method. Results are given and it was concluded that, considering the role that free ammonia plays in the nitrification process, a maximum holding time of 48 hrs. for free ammonia analysis is recommended. Further resources on this subject are listed.