Input from
domestic
customers
Input from
Environment
(Wet Weather)
Pressure
Sewer
Gravity
Sewer
Input from
industrial
customers
Bursts & Leakage
Pumping Station Overflows
Combined
Storm Overflows
Infiltration
Preliminary
Treatment
Primary
Settlement
Secondary
Biological
Treatment
Secondary
Settlement
(Tertiary
Treatment)
Secondary
Sludge
Storage
Sludge
Treatment
Biosolids
Energy
Discharge
to the
environment
Primary
Sludge
Storage
Sludge
Liquors
Primary
Sludge
Secondary
Sludge
Storm
Storage
Fig. 1
Typical wastewater system
114
O. Grievson