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Differentiate DWF and WWF; sources

Short answer

DWF is flow without rain, small and steady; WWF is flow during rain, much larger and variable. Sources of sanitary sewage include residential buildings (toilets, kitchens, baths), commercial and institutional establishments, industrial sanitary waste, public places, and groundwater infiltration.

Differentiate dry weather flow and wet weather flow. Briefly describe various sources of sanitary sewage.

Difference between DWF and WWF

PointDry weather flow (DWF)Wet weather flow (WWF)
MeaningFlow in sewer without rainFlow in sewer during or after rain
ComponentsDomestic + industrial sewage + infiltrationDWF + storm runoff
MagnitudeSmall and fairly steadyMany times greater, highly variable
DurationAlways presentOnly during rain
Use in designMinimum velocity check, treatment plant, separate sewersCapacity of combined and partially separate sewers, overflows
EstimationPopulation x per-capita flow x peak factorDWF + CiA/360CiA/360

Sources of sanitary sewage

  1. Residential: water closets, bathrooms, kitchens and laundry. This is the main source.
  2. Commercial: offices, hotels, restaurants, markets, shops.
  3. Institutional: schools, hospitals, colleges, hostels, public buildings.
  4. Industrial: sanitary wastes of employees, and process wastes where allowed.
  5. Public places: public toilets, bus parks, parks.
  6. Groundwater infiltration through leaking joints and manholes, and unauthorised connections such as roof drains.

✓ Answer checked by Claude Opus 5.5 (high effort)

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