7ae5a085_Lesson_8__Filamentous_Bacteria__Effect_of_Problem
[Name of Problem] Foaming/scum formation [Cause of Problem] Caused by (1) nondegradable surfactants and (2) the presence of Nocardia and sometimes (3) the presence of Microthrix parvicella [Effect of Problem] 
Foams float large amounts activated sludge solids to the surface of treatment units. Foam accumulates and putrefies. Solids can overflow into secondary effluent or overflow onto walkways.
Lesson 8: Filamentous Bacteria
Effect of Problem