MLVSS Calculator

Find mixed liquor volatile suspended solids.

MLVSS (mg/L) 2,400

Formula: MLVSS = MLSS × volatile fraction

Step-by-step with your numbers:

1. Values used:

2. MLSS = 3,000 mg/L

3. Volatile fraction (VSS/TSS) = 0.8

5. MLVSS = MLSS x Volatile fraction (VSS/TSS) = 3,000 x 0.8 = 2,400mg/L

Did we solve your problem today?

MLVSS estimates the active (organic) biomass in an activated-sludge wastewater process.

The math behind it

MLVSS = MLSS × volatile fraction. The volatile fraction (VSS ÷ TSS) is typically 0.7–0.85.

3,000 mg/L × 0.8 → 2,400 mg/L.

Why volatile?

Volatile solids approximate the living microbial mass doing the treatment.