Sewage Generation For Township Calculator

Work out sewage generation for township instantly with clear inputs, formula shown and shareable results.

About Sewage Generation For Township Calculator

Sewage flow is a fraction of water supplied, typically eighty percent, because the rest is consumed, evaporated or used outdoors. Groundwater infiltration and stormwater inflow are added on top. Sewers are sized on peak flow while treatment plants are sized on average flow with a margin, because treatment processes need steady loading.

Formulas

Average sewage flow

MLD = water supplied x return factor x (1 + infiltration allowance)

Peak flow

Peak = average x peak factor, typically 2.25 to 3.0

Worked example

With the default values below, Sewage Generation For Township Calculator returns Average sewage flow of 7.480. Change any input above and every figure here is recalculated in your browser.

Inputs used

Water suppliedminimum 0.001 MLD: 8.5 MLD
Return factor to seweraccepts 40–100 %: 80 %
Infiltration and inflow allowanceaccepts 0–50 %: 10 %
Peak flow factorminimum 1: 2.5

Results

Average sewage flow: 7.480 MLD
Peak sewage flow: 18.700 MLD
Infiltration allowance: 0.680 MLD
Treatment capacity with 20 percent margin: 8.976 MLD

Step by step

1Values used
2Average sewage flow
3Peak flow
4Average sewage flow= 7.480 MLD
5Peak sewage flow= 18.700 MLD
6Infiltration allowance= 0.680 MLD
7Treatment capacity with 20 percent margin= 8.976 MLD

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, fees or charges 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.
Preliminary estimate only. Sewerage design must follow the applicable manual on sewerage and sewage treatment.

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

Preliminary estimate only. Sewerage design must follow the applicable manual on sewerage and sewage treatment.

Frequently Asked Questions

How is the Sewage Generation For Township figure worked out?

MLD = water supplied x return factor x (1 + infiltration allowance). Sewage flow is a fraction of water supplied, typically eighty percent, because the rest is consumed, evaporated or used outdoors.

Why do sewers and plants use different design flows?

Sewers must physically carry the peak or they surcharge. Treatment plants use balancing and equalisation, so they are sized on average load with margin rather than the instantaneous peak.

What values do I need to enter?

This calculator takes 4 inputs: Water supplied, Return factor to sewer, Infiltration and inflow allowance, Peak flow factor. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.