LAUSR

The bloom of heterotrophic bacteria resulting from the presence of organic matter in wastewater streams can potentially affect the growth and activity of autotrophic ammonia-oxidizing bacteria (AOB), which are important for the operation of nitritation reactors. The present study evaluated the interactions between acetate-induced heterotrophs and the nitrosifying community using network analysis and the culture-dependence method. Bacterial succession as well as shifts in community structure occurred as a result of the bloom of heterotrophs. The acetate-induced heterotrophs enhanced reactor productivity and stability, thus increasing the ammonium removal efficiency in comparison to the control reactor from day 270 onwards (88.9 ± 10.0% vs. 60.0 ± 10.9%, P < 0.01). Interestingly, the sludge nitritation rates in the acetate-amended reactor (125.6 ± 33.1 mg-N/L/h) were much higher than those in the control reactor (81.7 ± 22.4 mg-N/L/h, P < 0.01) at stages IV and V, implying that the induced heterotrophs can ...