F:M ratio means Food to Microorganism ratio.
It compares:
- incoming organic load
to - available biomass
Why It Matters
The ratio affects:
- sludge health
- settling
- treatment stability
High F:M Ratio
High food levels may cause:
- young sludge
- dispersed growth
- unstable settling
Low F:M Ratio
Older sludge conditions may lead to:
- pin floc
- filament issues
- slower biology
Operators Adjust F:M By
- wasting sludge
- changing biomass concentration
- managing process conditions
Final Thoughts
F:M ratio helps operators understand whether the biology is overloaded or underfed. To see how operators track biomass alongside this, read how to read MLSS and MLVSS results.