Typ 021N Gram 1000X
Typ 021N Gram 1000X
Typ 021N Kristallviolett 100X
Typ 021N Lebendpräparat 100X
Typ 021N Lebendpräparat 100X
Typ 021N Lebendpräparat 1000X
Typ 021N Neisser 1000X
Type 021N
Rarely dominant in municipal sector – causes bulking sludge.
Morphology:
| Filament position: | projecting out of flake or free in aqueous phase |
| Branching: | none |
| Movement: | none |
| Growth habit: | straight / curved |
| Aufwuchs: | absent |
| Constrictions: | mostly present |
| Sheath: | none |
| Transverse walls: | clearly visible |
| Cell form: | disc to barrel-shaped |
| Length of filaments: | > 500 – 1000 µm |
| Filament diameter: | 1.5 – 2.5 µm |
| Gram staining: | negative with characteristic notches |
| Neisser staining: | negative |
| Sulphur test | positive |
Factors promoting growth:
- low to high sludge load
- presence of reduced sulphur compounds
- lack of oxygen injection
- easily degradable substrate (low molecular sugar, volatile fatty acids and amino acids)
- benefitted by ammonium injections
- N and P deficit
Countermeasures:
- balancing of C/N/P ratio
- increasing ventilation
- addition of iron-aluminium compound products with high bivalent iron content (e.g. FERRACLAR CLASSIC) in wastewater flow before activation stage