Lead contamination of potable water due to nitrification.

Nitrification can increase levels of soluble lead in potable water by reducing pH. The magnitude of the pH drop depends on the initial alkalinity and extent of nitrification. At 100 mg/L alkalinity as CaCO3, complete nitrification did not significantly decrease pH (pH stayed >7.

Inactivation of Nitrosomonas europaea and pathogenic Escherichia coli by chlorine and monochloramine.

The purpose of this study was to measure the chlorine and monochloramine inactivation kinetics of Nitrosomonas europaea at 21 degrees C in the presence and absence of particles. The inactivation kinetics rates were compared with those obtained with Escherichia coli O157:H7. The results show that, in pure water, the use of free chlorine produced 4 log10 of N.

Diversity of nitrifying bacteria in full-scale chloraminated distribution systems.

Chloramination for secondary disinfection of drinking water often promotes the growth of nitrifying bacteria in the distribution system due to the ammonia introduced by chloramine formation and decay. This study involved the application of molecular biology techniques to explore the types of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) present in several full-scale chloraminated systems. The results of AOB community characterization indicated the ubiquitous detection of representatives from the Nitrosomonas genus, with Nitrosospira constituting a negligible or small fraction of the AOB community in all but one sample.