The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species form...

In the early 2000s, most of the effluents from the Paris agglomeration (12 million inhabitants) were still discharged after only a standard activated sludge treatment of carbon, thus releasing a high ammonium load. This triggered the growth of nitrifying bacteria in the river and caused a deficit of dissolved oxygen concentration 200 km downstream, at the entrance of the estuarine area. From 20...

We will develop rapid screening tools to measure wastewater composition and correlate bulk composition measures to nitrification inhibition. Initially, we will focus on metals (cadmium, zinc, nickel and copper, which have been implicated in nitrification inhibition, moderate to high toxicity to nitrifying microorganisms. Prior to the start of the monitoring study, we will optimize and validate ...

2016 © American Water Works Association JOURNAL AWWA JULY 2016 | 108:7 Chloramine use is widespread in US drinking water distribution systems as a secondary disinfectant, and its use is predicted to increase with the final implementation of the Stage 2 Disinfectants and Disinfection Byproducts Rule (USEPA 2005). Chloramination is beneficial from the perspective of controlling formation of regul...

The effect of incubation time on most-probable-number estimates of autotrophic nitrifying bacteria was investigated by using waters, rooted aquatic plants, sediments, and slimes as inoculum sources. Maximum most probable numbers of the NH4+-oxidizing group were attained in 20 to 55 days (median, 25). Estimates of NO2-oxidizers were highest at termination (103 to 113) days.