You Have Found The Satan...!
Characteristics : Straight or smoothly curved trichomes, 1.4 - 2.5 micron in width and 100 - 500 micron in
length, found extending from the floc surface. Cells are rectangular (1.4 - 2.5 x 3.0 - 5.0 micron) with clear cell
septa without indentations at septa. No attached growth. A sheath is present. Gram negative and Neisser negative ;
however, a Gram - positive reaction may occur when sulfur granules are present. Neisser - positive granules may occur.
Cells frequently contain sulfur granules in - situ and this organism responds strongly to the "S" test. Apical gonidia
commonly are observed, and an inconspicuous hold - fast is present.
Identification : Relatively large, non-motile filaments (100-500 µm). Straight or smoothly curved filaments
with no branching. Cells are rectangular (1.4 x 2.5 µm) and a clear cell septa is present without indentations at the
septa. Filaments are found radiating outwards from the floc structure causing inter-floc bridging. The filament staining
is Gram negative or Gram variable when sulfur granules are present and Neisser negative with Neisser positive granules
observed frequently. Exhibits bright sulfur granules in the presence of sulfides under phase contrast (use the S-test).
Poly-ß-hydroxybutric acid (PHB) is frequently observed as dark intracellular granules. No attached growth when extending
into the bulk solution. Can form rosettes and the filaments can have gonidia on the tips. Rosettes are when many filaments
radiate outward from a common origin. Prominant heavy sheath. Easy to identify due to its large size.
Similar Organisms : Type 021N is similar when in the bulk solution and with no attached growth, although Type
021N has no sheath.
Environment : This filament is usually found in environments where there are limited nutrients (N or P). It can
also be found in wastes containing specific compounds with sulfides and/or organic acids or environments with low DO.
Sometimes found in plants with high pH in the aeration system..
Control : RAS chlorination should be definitely used if in the rapid growth phase. After chlorination, sheath
may still be present and interfere with SVI. Increase DO levels, add nutrients or lowering the pH according to the
problem. Septic wastes can be remediated by pre-aeration or pre-chlorination. Nutrient deficient wastes can be checked
by effluent values of residual NH3 and o-PO4 and should be supplemented if necessary.
Rank : Thiothrix ranks 5th in number of predominance.
It is usually easy to see the sheath on Thiothrix and distinctive rectangular cells compared to Type 0041 with more
square cells. With Thiothrix,the sheath is usually very visible and the cells are very rectangular and easy to pick out.
