|
Plant
Operations
Domestic and industrial
wastewater is discharged to the sewer system, where it flows by gravity or
through forced mains to wastewater treatment plant. The treatment process at the AWPC
can be classified into six (6) phases of treatment...
Preliminary Treatment is
provided by large grinder pumps called "muffin
monsters", and two mechanically cleaned bar screens. The major purpose of preliminary treatment is to
reduce the size of large solids in the influent flow, which protects the
remainder of the plant units from damage due to jamming.
Primary Treatment
is
provided by eleven (11) primary clarifiers. Primary clarifiers receive
raw sewage, as well as waste activated sludge. These tanks provide
necessary solids settling to the bottom of the tank, thus allowing the
clearer wastewater to flow to the next phase of treatment. The combination
surface scum collection and tank bottom screening flights are intended for
continuous operation to avoid breakage or drive failure. Raw sludge is
then pumped to raw sewage holding tanks for further treatment in the
biosolids division.
Activated Sludge Treatment
is
provided in ten (10) aeration tanks. Air is introduced into the mixed
liquor via fine air bubble diffusers in
order to provide an optimum oxygen level for both aerobic and anaerobic
bacteria growth. The mixed liquor from the aeration tanks is then
discharged to the secondary settling phase of treatment.
Secondary Treatment
occurs
in eleven (11) final clarifiers. These units are sludge collecting
units, similar to the process at primary treatment. However, the secondary
clarifier effluent quality may be expected to reflect 90% to 95% BOD
and Suspended Solids removal efficiency.
Disinfection
is obtained
by introducing chlorine gas into the secondary effluent flow. The
wastewater is chlorinated for proper disinfection in order to reduce the
pathogens to a permissible level prior to discharge to Cedar Creek.
The magnitude of the disinfection is dependent primarily on the length of
contact time and chlorine dose. The treatment plant is required to
provide disinfection only during the months April through October.
Tertiary and Post Aeration
Treatment - From the chlorine contact tank, the flow is then directed to
two 1.7 MG terminal ponds. The purpose of these ponds is to polish the
secondary effluent through various physical and biological processes before
the wastewater is post-aerated and discharged to Cedar Creek. At the
effluent end of terminal pond #2 is a static aerator, which provides
necessary dissolved oxygen prior to discharge to Cedar
Creek.
|
