The role of Lecane rotifers in activated sludge bulking control.

Experiments were conducted on Lecane inermis feeding on filamentous bacteria and living in activated sludge to determine if the rotifers can control the growth of the bacteria responsible for bulking. The experiments showed that Lecane are capable of significantly reducing the density of Microthrix parvicella filaments. The rotifers not only survived the transfer from the culture to the activated sludge, but they multiplied quickly when foraging on filamentous bacteria. By reducing the number of filaments, the rotifers improved settling properties of the sludge. This is apparently the first report on the possibility of using rotifers to control bulking.