Nitrification potential curves: a new strategy for nitrification prevention

In this article, nitrification potential curves are introduced as a possible operational strategy to prevent nitrification in chloraminated distribution systems. Nitrification potential curves are constructed based on the parameters that define growth and inactivation kinetics of ammoniaoxidizing bacteria in environments that contain chloramine and ammonia. To demonstrate the applicability of nitrification potential curves, long‐term, pilot‐scale studies that covered a range of chlorine‐to‐ammonia application ratios and chloramine residual concentrations that are typical of full‐scale chloraminated systems were conducted. The nitrification potential curve approach was effective in explaining why some of the pilot‐scale runs experienced nitrification while others did not based only on experimental measurements of total chlorine residual and free ammonia concentration. Because of the simplicity of the required measurements, nitrification potential curves can help define strategies to monitor and operate chloraminated distribution systems to prevent or minimize nitrification episodes.