Use of Lecane inermis for control of sludge bulking caused by the Haliscomenobacter genus

The excessive growth of filamentous bacteria that induce activated sludge bulking presents a serious problem in many wastewater treatment plants (WWTPs). In laboratory experiments, we tested the efficiency of Lecane inermis rotifers in reducing the abundance of Haliscomenobacter filaments in activated sludge samples from one municipal and one domestic WWTP. The results showed that the rotifers, by feeding on the bacterium filaments, are able to significantly reduce the quantity of Haliscomenobacter hydrossis-like bacteria. It was also shown that the effect of rotifers on filament abundance depends on the rotifer density, which is affected by the influent composition.