The Elmhurst Wastewater Treatment Plant (WWTP) has the capacity
to fully treat 20 million gallons of wastewater per day (mgd)
and can give primary treatment to an additional 40 mgd of wastewater,
if necessary, during excess flow conditions. The Wastewater Treatment
Plant had a record high flow of over 74 million gallons in one
day in February, 1997. An average day's flow of raw sewage entering
the Elmhurst WWTP results in approximately 6,540 pounds of dry
solids after concentration of suspended solids has been performed.
The Elmhurst WWTP has the capability of providing grit removal,
primary treatment, extended aeration, final clarification, and
disinfection of wastewater. This treatment is accomplished by
the movement of the sewage through a series of treatment tanks.
You'll notice that most of the equipment at the Wastewater
Treatment Plant is provided with an equal back-up. There are
more raw sewage pumps than are necessary as well as grit removal
equipment and sludge, pumps, etc. Illinois EPA design criteria
require that there be this redundancy to ensure reliable operation
of the Wastewater Plant in the event of the largest treatment
unit being out of service.
The sewage is first pumped using three enclosed screw
raw sewage pumps which provide a means of lifting the incoming
sewage from the sewer system.