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PUMP STATIONS
SKF – Manning
Ave., Merced St. & North
St. Lift Stations
Hydrogen sulfide corrosion in these lift stations prompted the
Selma Kingsburg Fowler Country Sanitation District (SKF) to seek
other alternatives to the original screw pumps. WBA and the District
evaluated submersible and self-priming pump alternatives and
decided upon submersible pumps. Based on this, WBA designed improvements
at several pump stations to incorporate the improvements. At
Manning Avenue the existing wet well was coated for corrosion
resistance, and two variable speed, 1200 gpm pumps were installed.
At the North Street station a new wet well was constructed using
concrete pipe sections lined with PVC to protect against hydrogen
sulfide related corrosion and two variable speed 900 gpm pumps
were installed. The design for 1800 gpm variable speed Merced
Street pump station included full coating of the existing interior
wet well for concrete corrosion protection and a walk-in control
room built half underground. The North Street Station was located
in downtown Selma, so the station design included sidewalks,
planter boxes, benches and landscaping. All stations were provided
with telemetry to the plant control room.
FSSD – 2002
Maintenance Project
WBA analyzed and designed the replacement of the variable speed
RAS pumping system and two raw sewage pumps with variable
speed drives as a part of this project for the Fairfield-Suisun
Sewer
District (FSSD). The RAS pumping system consisted was over
25 years old, and consisted of eight 40 hp pumps with eddy current
drives. We analyzed
the pumping capacity using field operating data to determine
whether the pumps should be repaired or replaced. We analyzed
the alternatives
for replacing the existing variable drive system based
on cost, harmonic distortion impacts, motor requirements, and
electrical
equipment location options. Based on this analysis, we
completed a design to replace the pumps, and install 6 pulse
VFDs. The design
included detailed construction sequencing constraints to
minimize interference with plant operations and modifications
improvements
to the SCADA system to incorporate the new equipment.
For the remote Cordelia Pump Station, we sized two new pumps based
on District flow projections. We evaluated VFD alternatives and
repair versus replacement of the 100 hp motors for use with the
new VFDs. Based on these analyses, the design included new 2500
gpm pumps with 18 pulse VFDs and 125 horsepower motors.
COLLECTION SYSTEMS
DSRSD – Eastern
Dublin Trunk Sewer II
WBA provided detailed general and civil design of approximately
2,100 ft of new 36" gravity trunk sewer in Eastern Dublin
for the Dublin San Ramon Services District (DSRSD). The trunk
sewer design included a creek crossing and was coordinated with
and constructed prior to a major expansion of Dublin Boulevard
by the City of Dublin.
Because of its distance
from the District’s wastewater treatment
plant and the presence of the creek, the sewer was relatively deep – up
to 25-feet below grade. In addition, a thick layer of saturated
sand extending over one-half of the total length was discovered
by the soil borings made as part of the preliminary design phase.
As a result, extra effort was taken during the detailed design
phase to properly define the extent of the project potentially
subject to difficult construction conditions. Both the Tassajara
Creek and Tassajara Road crossings were accomplished with minimum
disruption to traffic and the environment by using bore and jack
methods.
SFK – Sewer
System Master Plan
WBA completed a Sewer System Master Plan for the Selma-Kingsburg-Fowler
County Sanitation District (SKF) in Fresno County in 2001. SKF
serves a population of over 25,000 in three adjoining cities
in Fresno County. The service area contains approximately 7.5
square
miles and has about 138 miles of pipe up 48-inches in diameter.
For this work, we used the Hydra Version 6.0 software and coordinated
the acquisition of digital orthographic data for the area. Over
1,800 manholes were surveyed and located using GPS to the manholes
to be incorporated into the digital orthophotos.
WBA calibrated the model from data collected from 7 metering station
as well as 9 pump stations. Based on the modeling, we were able
to identify diurnal and peak flows, and groundwater infiltration
and inflow volumes. We identified those sections of the system
that would not accommodate the projected 2020 flows. We found a
few sections of pipe that sloped in the wrong direction. The plan
concluded with recommendations for the size and the timing of system
modifications.
DSRSD – Parks
RFTA Sewer Replacement
The Dublin San Ramon Services District (DSRSD) entered
into a contract with the U.S. Army to own and operate the
water and sewer utilities
on Parks Reserve Forces Training Area (Parks RFTA). Part of the
agreement called for the District to rehabilitate the majority
of Parks RFTA’s sewer system that was over 50 years old
and severely deteriorated. WBA assisted the District with a video
inspection
of the lines and recommended replacing about 25,000 feet of pipes.
The recommended replacements eliminated about 10,000 feet of
unused pipes and located the remainder under dedicated streets
rather
than in open fields and under buildings. WBA completed the initial
design project, which involved installing about 15,000 feet of
8-inch through 21-inch diameter line including about 200 feet
of bore and jack pipe.
The above projects are representative of our experience in this area.
If you
would like additional information on these, or other projects that
we
have completed, please contact us.
For detailed descriptions
of representative projects in our other areas of expertise,
click below on the category you are interested in:
Wastewater:
Recycled Water:
Water Supply:
Alternative Energy:
- Economic Evaluations
- Technology Selection
- Waste to Energy Services (Cogeneration)
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Areas:
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