Type 0961

This type is very rare in municipal sewage plants; in industrial plants (breweries and dairies) it can occur in large quantities and cause bulking sludge. Little research has been conducted into the filamentous type.

Morphology:

Filament position:	projecting out of flake or free in aqueous phase
Branching:	none
Movement:	none
Growth habit:	straight / slightly curved
Aufwuchs:	absent
Constrictions:	clearly visible
Sheath:	absent
Transverse walls:	clearly visible
Cell form:	rectangular
Length of filaments:	> 200 µm
Filament diameter:	1.0 – 2.0 µm
Gram staining:	negative
Neisser staining:	negative
Special features:	transparent, rectangular cells

Factors promoting growth:

high sludge load > 0.2 kg BSB5 / kg TS * d
wastewater with high concentration of easily degradable substrates

Countermeasures:

Reduction of sludge load
Setting up a substrate gradient
Dosage of FeSO4

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