Small flagellates (small zooflagellates)

  • 5 – 20 µm
  • 1 – 2 flagella
  • free-floating or sessile
  • jittery movements

 

In activated sludge:

  • common during start-up of sewage treatment plants
  • after various issues (e.g. overloading, lack of ventilation, poisoning of ciliates)