 |
|
|
American Water Enterprises
3100 South Lewis Blvd, RR6
Sioux City, IA 51106
Phone - 712-279-6916
Fax - 712-279-6191
|
|
Wastewater Treatment Plant History
The original WWTP was constructed in 1961. Although receiving many updates, much
of the WWTP, particularly the mechanical systems, have not been updated until
the commencement of the current major renovation process.
General
The original WWTP consisted of the following processes: preliminarily
treatment and primary settling. The primary bar screen and clarifiers comprising
the 1961 plant are referred to as the North Plant. The North Plant is currently
out of service and is not in use due to mechanical and structural failure. The
significant repairs needed to bring the North Plant primary clarifiers back into
service are underway with the Phase IA rehabilitation project.
In 1978, the WWTP was upgraded by the addition of a duplicate system of
mechanical screens, grit removal, and primary treatment; such additions are
known collectively as the South Plant. The South Plant currently treats all of
the incoming flows to the WWTP.
The secondary activated sludge process was added to the WWTP in the 1978
upgrade. At the time of the 1978 plant upgrade, the secondary treatment train
consisted of primary effluent pumping, aeration using centrifugal blowers and
synthetic fabric diffuser tubes, secondary clarification, and return activated
sludge pumping.
At the time of the 1978 plant upgrade, secondary aeration of the activated
sludge was accomplished using synthetic diffuser tubes. A 1999 plant upgrade
replaced the synthetic fabric diffusers in three of the four aeration basins
with flexible membrane diffusers.
In 1985, three additional centrifugal blowers were added to the secondary
aeration system in order to reduce the overall power consumption for the
aeration system during periods of lower oxygen demand.
The original WWTP constructed in 1961 included anaerobic digestion of primary
sludge. Digested sludge was land applied to farm land.
The 1978 plant upgrades added anaerobic digesters, disk/nozzle centrifuges for
sludge thickening, and storage lagoons.
In 1988, the disk/nozzle centrifuges were removed and replaced with gravity belt
thickeners for was sludge thickening. In addition, a polymer feed system for the
gravity belt thickeners, miscellaneous pumping, HVAC, and electrical
improvements were also installed.
In 1999, a major upgrade to the WWTP was completed and included the following
items:
1. Replacement of all four primary digester covers with fixed covers,
including new gas safety equipment and level sensors;
2. Replacement of one secondary digester cover with a new gas holder cover,
including new gas safety equipment and level sensors;
3. Addition of three draft tube mixers mounted exterior to the tank for each of
the primary digesters;
4. Construction of a new sludge line for primary and waste sludge transfer to
all primary digesters;
5. Replacement of bar screens at the headworks of the WWTP; and
6. Installation of a non-potable water system
In 2006, American Water, CDM and the City of Sioux City finalized the design of
a $31.8 million plant rehabilitation project. With the new improvements comes a
new Headworks Building, a Sodium Hypochlorite Disinfection Building, a complete
rehab to the North Primary Clarifiers, a complete Odor Control System, and some
ADA and code compliance renovations to the Administration Building. The new
Headworks Building will house three belt filter presses used to dry the sludge
to an 18% cake solid where it will then be transported to LP Gill Landfill in
Nebraska for ultimate disposal. This will eliminate the need for the odor
generating on-site sludge storage lagoons. The existing lagoons will then be
demolished and the area will be converted into a park with a natural wetland
area, fishing pond and trails to be enjoyed by the public. The Sodium
Hypochlorite disinfection system will increase plant staff and public safety by
eliminating the gaseous chlorine systems currently being used. Now that we have
received the more stringent NPDES operating permit limits, the building will
also house two Sodium Bisulfite tanks used in the removal of chlorine residual
prior to the waste stream discharging into the Missouri River.
|
|
 |
|
