High Efficiency of Removal of Pathogenic Microorganisms at Wastewater Treatment Plants in the City of Moscow

— While most pathogenic bacteria are efficiently removed from wastewater during biological treatment, some pathogens, notably Arcobacter , may be abundant in the purified water. Using 16S rRNA gene profiling, the composition of microbial communities of municipal wastewater in the city of Moscow was studied before and after biological purification at the Lyubertsy wastewater treatment plant. Fecal contaminants of the genera Acinetobacter , Aeromonas , Arcobacter , Bacteroides , Streptococcus , and Veillonella , which include human pathogens, predominated in the influent wastewater. After treatment, the relative abundance of these bacteria decreased by 50‒100 times. Predominant organisms in the microbiome of the effluent water were bacteria characteristic of activated sludge, including the nitrifiers of the genera Nitrospira and Nitrosomonas , as well as phosphate- and glycogen-accumulating microorganisms. Thus, pathogenic bacteria, including Arcobacter , are effectively removed at the Moscow wastewater treatment plant.