You Have Found The Satan...!
Characteristics : Relatively short (10 - 100 micron), curved or bent filaments composed of round - ended,
rod - shaped cells (0.7 - 1.0 x 1.0 - 2.0 micron) contained in a clear, tightly fitting sheath. Cell septa are clear
with indentations at septa. Filaments found predominantly intertwined within the floc interior with only short filaments
extending into the bulk solution. No branching. Gram negative, Neisser negative, no sulfur granules; PHB frequently
observed. Attached growth of epiphytic bacteria is almost always observed, making observation of individual cells
difficult.
Identification : Relatively short , non-motile filaments (20-100 µm). Bent or curved with no branching. The cells
are round-ended and rod shaped "sausages" (0.7-1.0 x 1.0-2.0) and are contained in a clear, tightly fitting sheath. The
cell septa are clear and easily observable with indentations at the septa. Filaments are usually found intertwined in the
floc structures with only short filaments extending into the bulk solution and can cause sludge settling interference by
open and diffuse floc. If the filament is observed radiating outward from the floc structure and does not have a lot of
attached growth, this is a sign of excelerated growth. The filament is usually Gram negative and Neisser negative. There
are no sulfur granules. Poly-ß-hydroxybutric acid (PHB) is almost always observed as dark intracellular granules. In
wastewater that is nutrient deficient, an exocellular slime coat may be present. Heavy attached growth is usually common
making it difficult to see individual cells. Attached growth is usually perpendicular to the filament trichome.
Similar Organisms : S. Natans may be related, but the diameter is much larger and has distinctive false branching.
Type 0675 is similar if false gram staining reaction although Type 0675 has square-ended cells and the cause for Type 0675
is low F/M and not low DO.
Environment : This filament is usually found in environments where there is low DO but reasonable F/M ratios. Can
be caused by too long RAS lines or sludge being held too long in the secondary clarifier.
Control : RAS chlorination can be used to get rid of the filaments but process changes should also be made. Cell
lysis occurs readily on this type of filament, although the empty sheaths still remain. Sludge wasting is necessary to
remove them entirely from the system. Manipulation of F/M and DO concentration can be used to control the filaments.
Rank : Type 1701 ranks 2nd in number of predominance.
