MBBR Media Volume Calculator

Work out mbbr media volume instantly with clear inputs, formula shown and shareable results.

About MBBR Media Volume Calculator

Moving bed biofilm reactors are sized on surface area rather than volume: required area is the load divided by the surface loading rate, typically 5-8 g BOD/m2/day for carbon removal and 0.8-1.5 g N/m2/day for nitrification. Media fill is capped around 60-70% so the carriers can circulate freely.

Formulas

Biofilm area

Area (m2) = BOD load (g/day) / surface loading rate (g/m2/day)

Volumes

Media volume = area / specific area; tank volume = media volume / fill fraction

Worked example

With the default values below, MBBR Media Volume Calculator returns Media Volume Required of 266.667. Change any input above and every figure here is recalculated in your browser.

Inputs used

BOD Loadminimum 0 kg/day: 800 kg/day
Surface Area Loading Rateminimum 0 g BOD/m2/day: 6 g BOD/m2/day
Media Protected Surface Areaminimum 0 m2/m3: 500 m2/m3
Media Fill Fractionaccepts 0–70 %: 50 %

Results

Media Volume Required: 266.667
Tank Volume Required: 533.33
Biofilm Surface Area Required: 133,333
Effective Area Per Tank Volume: 250.00

Step by step

1Values used
2Biofilm area
3Volumes
4Media Volume Required= 266.667
5Tank Volume Required= 533.33
6Biofilm Surface Area Required= 133,333
7Effective Area Per Tank Volume= 250.00

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why cap the fill fraction?

Above about 67% the carriers no longer circulate freely, leading to dead zones, uneven biofilm and clogging of the retention screens. Most designs use 40-60%.

What advantage does MBBR have over activated sludge?

No sludge return, no bulking risk, compact footprint and resilience to load shocks. It needs a downstream solids separation step but does not depend on sludge settleability.