You Have Found The Satan...!
Characteristics : Straight, irregularly - curved or bent filaments, 0.8 - 1.0 micron in diameter and 10 - 60 micron
in length, found mostly within the floc. Cells are rectangular (0.8 x 1.5 micron) without constrictions at septa, or with
constrictions that are hard to observe. Neither attached growth nor a sheath is present. Cells stain Gram negative and the
entire trichome stains Neisser positive (purple). No sulfur granules.
This filament often is overlooked, or its abundance underestimated, until the Neisser stained slide is examined. Filaments
appear wider (1.0 - 1.2 micron) in dried, stained smears.
Identification : Relatively small, non-motile filaments (10-60 µm). Straight, irregularly curved or bent filaments
with no branching. Cells are rectangular (0.8 x 1.5 µm) and no constrictions at the septa. Filaments are found mostly
within the floc structure causing diffuse floc with poor settling. The filament staining is Gram negative and Neisser
positive. It is usually overlooked until stained and then it’s easy to identify due to the fact that the entire trichome
stains Neisser positive. The filament appears wider when dried on a slide and stained. Intracellular granules not observed.
No sulfur granules. Usually no attached growth. No Sheath is present.
Similar Organisms : Microthrix parvicella is similar only in causes and usually appears along side of Type 0092.
Type 0092 is easily identified when you perform a Neisser stain. Then the filament literally jumps out at you with it's
bright purple stain. It gets easier to go back then and look at your wet mount and gram stain and find it.
Environment : This filament is usually found in environments where there low F/M (0.02-0.2) and with a long MCRT
(10-40 days).
Control : F/M can be changed by increased sludge wasting, changing from complete mix to plug flow or use of a
selector. Reducing sludge age will help also.
Rank : Type 0092 ranks 8th in number of predominance. It can sometimes be observed with Microthrix
parvicella.
