Wider presence of accelerated chemical chloramine decay in severely nitrifying conditions

Popularity of chloramine has been dampened by nitrification, which is believed to highly accelerate chloramine decay. This can seriously compromise the primary goal of using chloramine as a secondary disinfectant. Our previous laboratory-scale studies showed that highly accelerated chemical decay of chloramine was caused by soluble microbial products (SMPs) released by microbes under severely nitrifying conditions. To understand whether a similar phenomenon exists in full-scale distribution systems, samples were collected from four full-scale systems supplied from different water sources and have been compared with results obtained from laboratory-scale systems. The results verified that the acceleration typical in severely nitrified water is common in full-scale chloraminated systems under severely nitrifying conditions.