Filamentous Bulking in Massachusetts: Extent of the Problem and Case Studies

A handbook has been written for control of activated sludge bulking for wastewater treatment plant operators in Massachusetts. In order to demonstrate the principles described in the handbook for filamentous organism identification and subsequent selective control, six Massachusetts activated sludge plants experiencing bulking problems were investigated. In addition, a survey was conducted to determine the extent of the filamentous bulking problem in Massachusetts. Dominant filamentous organisms in the aeration tank mixed liquor were identified to determine the probable cause of bulking problems. Plant data and operating conditions were also studied to verify the organism-cause relationship. Based on the sample and data analysis, selective control strategies were suggested to the plant operator to control or eliminate the bulking problem.