Calculating the Fraction of Biomass in the Mixed Liquor Volatile Suspended Solids (MLVSS)

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Calculating the Fraction of Biomass in the Mixed Liquor Volatile Suspended Solids (MLVSS)

Below you can find the typical formulas, coefficients and empirical data used to establish the basic design of a complete mix suspended growth biological sewage wastewater process.

To use this calculator please fill in the input value data of your sewer wastewater and as a result some basic plant design and effluent BOD data will follow out of the calculations. If the normal sewer water characteristics are unknown, please press the "typical data" button for an autofill of the input fields.
More information and theory about the Input Parameters and the Kinetic Coefficients you can find in the Documentation.

Documentation
This formula will establish the Fraction of Biomass of an sewer wastewater treatement plant:

Where:

Characteristics of Primary Sedimentation Effluent
influent soluble substrate concentration (bsCOD)	S₀ =	BOD or bsCOD g/m³
nbVSS concentration in influent	X_0,i =	g/m³ or mg/l
Solids Retention Time (SRT)	SRT =	d

Kinetic Coefficients
maximum rate of soluble substrate utilization	k =	g COD/g∙d
biomass yield	Y =	g VSS/g COD used
endogenous decay coefficient	k_d =	g VSS/g VSS∙d
half-velocity constant	K_s =	g COD/m³
fraction of biomass that remains as cell debris	f_d =	g VSS/g VSS



The fraction of biomass in the MLVSS is:	X/X_T =	g VSS/g bsCOD