A full scale application in the control of the filamentous bulking generated by Type 021N F. thiothrix sp.

The presence of industrial effluent in the wastewater incoming to municipal activated sludge treatment plants sometimes causes bulking events. In order to control one of these events a strategy of bacterial selection was applied with an anoxic selector before the main oxidation basin utilising the screw pumps basin. The result of this work confirms what is reported in the literature about the possibility to utilize a metabolic control of some filamentous forms (particularly Type 021N) with high organic load. The remedial action could be realized using already existing facilities, without any additional costs.