Haliscomenobacter hydrossis

The filamentous type is found in municipal and industrial plants with high nitrogen loads (dairies and meat-processing plants).

 

Morphology:

Filament position: projecting out of flake
Branching: none
Movement: none
Growth habit: straight and needle-like
Aufwuchs: absent
Constrictions: none
Sheath: present
Transverse walls: not visible
Cell form: rod-shaped
Length of filaments: < 200 µm
Filament diameter: 0.3 – 0.4 µm
Gram staining: negative
Neisser staining: negative

 

Factors promoting growth:

  • high nitrogen load
  • high concentration of short-chain carbon compounds
  • low oxygen level
  • old sludge
  • low phosphorous level
  • oxygen deficiency
  • fully mixed activation tanks
  • sludge load > 0.2 kg BSB5/ kg TS * d

Countermeasures:

  • setting up a plug flow or high-load zone
  • brief increase to pH 9
  • addition of hydrogen peroxide