You Have Found The Satan...!
Characteristics : Smoothly - coiled filaments, 0.4 - 0.7 micron in diameter and 100 - 200 micron in length, found
mostly within the floc but may occur in "patches" free in solution. No sheath and no no cell septa. No sulfur granules and
no attached growth. Gram negative and Neisser negative. This filamentous microorganism appears similar to
M.parvicella, but differs in its Gram and Neisser staining reactions.
Identification : Medium length, non-motile filaments (100-200 µm). Smoothly coiled filaments with no branching.
Cells are rectangular (0.4 x 0.7 µm) and with a rigid trichome. There is no cell septa. Filaments are found mostly within
the floc structure but may occur free in the bulk solution in patches. The filament staining is Gram negative and Neisser
negative. No attached growth. No sulfur granules. No sheath.
Similar Organisms : Microthrix parvicella is similar although it differs in staining reactions.
Environment : This filament is usually found in environments where there low F/M with a long MCRT. This can be
either a high MLSS concentration or a low BOD loading (<.2 lbs/BOD/lbs MLSS/day).
Control : F/M can be changed by intermittent feeding, increased sludge wasting, changing from complete mix to
plug flow or use of a selector. RAS chlorination should be used.
Rank : Type 0581 is ranked 15th in predominance.
