Lecane tenuiseta (Rotifera, Monogononta) as the best biological tool candidate selected for preventing activated sludge bulking in a cold season

AbstractRotifers in activated sludge reduce the quantity of dispersed bacteria, ingest filamentous bacteria, enhance flocculation and limit biomass production. Growth rates of rotifers are inversely correlated with temperature; thus, their density declines drastically in wastewater treatment plants (WWTPs) during the winter. The only species already demonstrated to be able to control bulking is Lecane inermis. However, they cease proliferation at 8°C. The goal of our research was to select other rotifers species whose growth rates at lower temperatures are sufficiently high to maintain a favourable density during cold seasons. We conducted selection experiments in the laboratory at temperatures reflecting the temperature distribution in the majority of municipal WWTPs in the temperate zone. In the first experiment, the general selection stage, we tested the influence of the temperatures 8, 15 and 20°C on competition among different rotifer taxa in sludge samples originating from different WWTPs. The rotif...