Sewage Flow Calculator
Estimate the wastewater flow rate from a community based on water consumption and a return factor.
Average Sewage Flow
1,600 m^3/day
Average Sewage Flow vs Average Water Demand
Formule
## Sewage Flow Estimation Wastewater flow is derived from water consumption, reduced by a return factor. ### Formulas **Average sewage = Water demand x Return factor** **Peak sewage = Average x Peak factor x (1 + Infiltration)** The return factor (0.7-0.9) accounts for water consumed (irrigation, evaporation) that does not reach the sewer. The peak factor accounts for diurnal variation, and infiltration accounts for groundwater entering through pipe joints.
Exemple Résolu
2000 m^3/day water demand, 0.8 return factor, 2.5 peak factor, 10% infiltration.
- 01Average sewage = 2000 x 0.8 = 1600 m^3/day
- 02Peak sewage = 1600 x 2.5 x 1.10 = 4400 m^3/day
- 03Peak flow rate = 4400 / 86.4 = 50.9 L/s
Questions Fréquentes
What is the return factor?
The return factor (0.7-0.9) is the fraction of water supply that becomes wastewater. Arid regions with garden irrigation use 0.7. Cooler climates with less outdoor water use have 0.85-0.90. Industrial areas vary widely.
What causes peak flows in sewers?
Peak flows occur during morning and evening when residential water use is highest. The peak factor depends on population size: small communities may have peak/average ratios of 3-4, large cities 1.5-2.
What is infiltration and inflow (I/I)?
Infiltration is groundwater seeping through pipe joints and cracks. Inflow is stormwater entering through illegal connections, manhole covers, etc. Combined, I/I can add 15-50% to dry weather flow in older systems.
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