Application of fluorescence in situ hybridization for the study and characterization of nitrifying bacteria in nitrifying/denitrifying wastewater treatment plants.

The aim of this study was to verify fluorescence in situ hybridization for the detection of nitrifying bacteria in activated sludge and biofilms, and to determine the distribution of nitrifiers in selected wastewater treatment plants (WWTPs). Both Czech and foreign WWTPs with intensification of nitrification (for example, in situ bioaugmentation of nitrification or biofilms) and without intensification were studied. The two-dimensional and three-dimensional analyses of microscopic images were focused on quantifying the parameters and their differences with regard to the arrangement, capacity and sludge age of the WWTPs. This is the first time such a study has been performed in the Czech Republic.