MLVSS Calculator

MLVSS Calculator

Calculate Mixed Liquor Volatile Suspended Solids for wastewater treatment analysis

Calculate MLVSS

Calculate MLVSS using flow rates, COD values, and F/M ratio

Volume of mixed liquor entering the aeration tank per hour

Food to microorganism ratio (typically 0.3-0.6)

COD of mixed liquor entering the aeration tank

COD after primary treatment in aeration tank

Aeration Tank Dimensions

Freeboard is the distance between the wastewater level and tank top

MLVSS Results

0.0000
Flow (MGD)
0.0
Primary Effluent COD (mg/L)
0.0
COD Added (lbs/day)
0.0
Tank Volume (ft³)
0.0
MLVSS Mass (lbs/day)
0.0
MLVSS Concentration (mg/L)

Formula used: MLVSS (mass) = COD added to aeration ÷ F/M ratio

Concentration: MLVSS (conc.) = MLVSS (mass) ÷ (Volume × 8.34 × 10⁻⁶)

Flow conversion: 0 GPH = 0.0000 MGD

MLVSS Analysis

Enter your wastewater treatment parameters to see MLVSS analysis and operational recommendations.
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Understanding MLVSS in Wastewater Treatment

What is MLVSS?

MLVSS (Mixed Liquor Volatile Suspended Solids) represents the concentration of active bacteria in an activated sludge wastewater treatment system. These microorganisms are responsible for breaking down organic matter in sewage.

Key Components

  • Mixed Liquor: Combination of raw wastewater and activated sludge
  • Volatile: Components destroyed at 550°C (mainly bacteria)
  • Suspended Solids: Particles larger than 2 microns

Calculation Methods

Industrial Method

Uses flow rates, COD values, and F/M ratio for plant-scale calculations

Laboratory Method

Direct measurement using sample weights and volumes

Typical MLVSS Ranges

Conventional Activated Sludge:1500-3000 mg/L
Extended Aeration:3000-6000 mg/L
High Rate Systems:1000-2000 mg/L

Industrial Calculation Formula

Flow (MGD) = Flow (GPH) × 24 ÷ 1,000,000

Primary Effluent COD = Influent COD - Treated COD

COD Added = Flow (MGD) × Effluent COD × 8.34

MLVSS (mass) = COD Added ÷ F/M Ratio

MLVSS (conc.) = Mass ÷ (Volume × 8.34 × 10⁻⁶)

Laboratory Calculation Formula

MLSS = (Sample + Filter - Filter) ÷ Volume

Fixed Solids = (Ash + Crucible - Crucible) ÷ Volume

MLVSS = MLSS - Fixed Solids

Note: Laboratory method requires careful sample handling and precise measurements for accurate results.

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