Filamentous Bacteria Identification & Process Control

Filamentous Bacteria Identification & Process Control

Under normal ​conditions in ​activated ​sludge, ​bacteria occur ​singly, in ​small chains or ​clumps. Under ​adverse ​conditions ​however, ​bacteria that ​grow in ​filaments begin ​to form longer ​chains called ​filamentous ​bacteria or ​“​filaments”​.

Filaments can ​dominate in the ​wastewater ​treatment ​system under a ​variety of ​conditions. ​These ​conditions are ​usually less ​favorable for ​the floc-​forming ​bacteria so, ​this allows the ​filaments to ​gain an ​advantage. The ​presence of ​some filaments ​in the ​activated ​sludge is ​advantageous. ​

They aid in ​settling by ​providing a ​“back-​bone” for ​floc-forming ​bacteria to ​attach to. ​However, when ​filaments begin ​to grow in ​excess amounts, ​extending from ​the floc into ​the bulk fluid, ​they can ​interfere with ​settling and my ​cause foaming ​upon aeration. ​

Different ​types of ​filaments ​dominate under ​different ​conditions. ​Identifying ​which filaments ​are dominating ​in the system ​will help the ​operator to ​understand the ​condition in ​the treatment ​system so that ​corrective ​changes can be ​made. ​

Microscopic ​evaluations to ​identify ​filamentous ​bacteria can be ​complicated and ​time consuming. ​This lesson ​will provide a ​simple approach ​to identifying ​filaments in ​the activated ​sludge as well ​as provide ​suggestions for ​corrections. ​