MLSS stands for Mixed Liquor Suspended Solids.
In simple terms, it measures the concentration of solids in the aeration basin.
Why MLSS Matters
MLSS represents the biological population treating wastewater.
Too little biomass:
- weak treatment
Too much biomass:
- oxygen demand issues
- settling problems
Operators Use MLSS To
- monitor treatment strength
- adjust wasting
- stabilize the process
- support nitrification
Important Reminder
MLSS alone does not tell the full story.
Operators also evaluate:
- sludge age
- settling
- oxygen levels
- clarifier performance
Final Thoughts
MLSS is one of the core measurements operators use to understand biological treatment health.