Biofilter

Indicative calculation of minimum biofilter volume from organic and hydraulic loading, including volume per PE and estimated plan area and diameter.

Biofilter – indicative sizing

This calculator provides an indicative sizing of a biofilter based on organic (BOD₅) and hydraulic loading. It computes the minimum required volume from both criteria, selects the larger one, derives the volume per PE and, for a given bed height, estimates the plan area and diameter of a circular biofilter. Results are indicative only and intended for preliminary design and checks.

Population equivalent [PE]

Average daily flow Q24 [m³/day]

Specific BOD₅ load [g BOD₅/PE/day]

Packing specific surface [m²/m³]

Design hydraulic loading [m³/m²/day]

Max. areal organic loading [g BOD₅/m²/day]

Filter bed height [m]

The calculation is simplified and uses average daily values. It does not include multiple stages, recirculation or detailed hydraulics. Use it as an indicative tool for preliminary sizing and checks only.

Biofilter design

Total BOD₅ [g/day]: –

Volume from organic loading [m³]: –

Volume from hydraulic loading [m³]: –

Design volume [m³]: –

Design volume per PE [m³/PE]: –

Governing criterion: –

Actual hydraulic loading [m³/m²/day]: –

Actual areal organic loading [g/m²/day]: –

Plan area [m²]: –

Biofilter diameter [m]: –

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