Matteo: I agree with ...
Published by Leah Miller, Wastewater Treatment Plant Supervisor / Environmental Coordinator at Foremost Farms USA
Matteo:
I agree with others' comments - find out which Filamentous organism is causing the problem (probably Nocardia or Microthrix), reduce FOG in the Influent, reduce Sludge Age (MLSS) if possible while keeping good treatment, remove as much of the foam as possible from all basins (the foam is filamentous bacteria, not a by-product). A note on the Anoxic selector - at my plant, we use an Anaerobic selector for filamentous control and it works very well. The HRT is 2 hours - when we drop below this, the foam levels definitely go up. If possible it may be helpful to run the ORP lower in your selector. Ours normally runs below -350 mV. Best of luck.
Leah