Filamentous organism bulking in nutrient removal activated sludge systems - Paper 11: A biochemical/microbiological model for proliferation of anoxic-aerobic (AA) filamentous organisms

A model is presented that describes the competitive growth behaviour of flo c-forming and anoxic-aerobic (AA) filamentous organisms in long sludge age nitrogen (N) and nitrogen and phosphorus (N&P) removal activated sludge sys tems. The model, referred to as the bulking model, establishes the potentia l for filamentous organism proliferation under various aeration and substra te feeding regimes. Based on the principles of the model, system configurat ion and operational procedures are proposed for the amelioration of bulking and are tested experimentally. To examine the general applicability of the bulking model it is tested by applying it to the experiments described by Lakay et al. (1999) and Musvoto et al. (1999). [Note: Throughout descriptio n of the bulking model, the terms filamentous and filaments refer specifica lly to AA filaments (formerly designated low F/M filaments), which are asso ciated with poorly. setting sludges in long sludge age N and N&P removal sy stems].