Calculating the effluent BOD or bsCOD

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Calculation of the effluent bsCOD

Below you can find the typical coefficients and 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 calculation. 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 wastewater bsCOD level after treatment:

Where:

Characteristics of Primary Sedimentation Effluent
Sedimentation 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



Effluent soluble substrate concentration (bsCOD) is:	S =	g bsCOD/m³

S =	effluent soluble substrate concentration (bsCOD)	[g bsCOD/m³]
K_s =	half-velocity constant	[g COD/m³]s
k_d =	endogenous decay coefficient	[g VSS/g VSS∙d]
SRT =	Solids Retention Time	[d]
Y =	biomass yield	[g VSS/g COD used]
k =	maximum specific soluble substrate utilization rate	[g COD/g∙d]
f_d =	fraction of biomass that remains as cell debris	[g VSS/g VSS]