Margaret E' Tanner, P'E'

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SOCIETY OF AMERICAN MILITARY ENGINEERS SAVANNAH
DISTRICT MAY 8, 2008
GEORGIA PORTS AUTHORITY SAVANNAH HARBOR
REOXYGENATION DEMONSTRATION PROJECT

• Margaret E. Tanner, P.E.
• Project Manager
• Larry A. Neal, P.E.
• Senior Principal
• Tanya Kinnard
• Project Coordinator
• MACTEC Engineering and Consulting, Inc.

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Project Issues

• Portions of the harbor are listed on the 303(d)
  for low dissolved oxygen (DO) based on the
  disapproved Georgia DO criteria
• Proposed deepening to 49 feet
• Deepening of the harbor will reduce the
  reaeration capacity of the system
• Modeling indicates that lost reareation may
  reduce the DO by approximately 20,000 lbs/day

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Savannah River
Demonstration Project Location
Listed Segment
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Project Goals

• To demonstrate that technologies exist capable of
  mitigating for lost reaeration
• Monitor the impacts to water quality

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Cause of Low DO from Deepening
O2 Transfer
O2 Transfer
O2
O2
Water Velocity
Water Velocity
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The Reoxygenation System

• The system design is barge (spud barge) mounted
• 2 12 diameter, 22 tall Speece Cones
• 4 400 hp Godwin Pumps with VFDs
• 300 of 18 HDPE Piping
• Intakes designed to limit impingement
• Potential oxygen transfer efficiency gt95
• Designed to inject 30,000 lbs/day

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The Reoxygenation System
Pump
Oxygen Lines
Pump
Pump
Pump
Plan View
Speece Cones
Variable Frequency Drive Controllers
Pumps
Front Elevation
Side Elevation
Intake Screen
Return Line
10o
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Speece Cone
Q, V1

• Pressure is high (100 to 150 feet) so oxygen
  dissolves
• As diameter increases, the velocity decreases
• Bubbles escape and remain in the cone
• The exit dissolved oxygen concentration (C2) is
  much greater than the inlet concentration (C1)

C1
O2
FB
C2
Q, V2
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The System
Air Relief Valve
Transformer
Electrical Switch Gear
Vaporizers
Oxygen Tank
Oxygen Injection Line
400 HP Pumps
Intake Lines
Oxygen Line
Speece Cone
DO Monitoring Station
Variable Frequency Drives (VFDs)
Electrical Lines
Return Line
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Operation

• Monitoring began June 25, 2007
• Ended September 26, 2007
• Assembly was relatively completed on August 3
• System shakedown approximately 5 days
• Official Startup August 7, 2007 - 100 p.m.
• Shutdown September 16, 2007 800 a.m.

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System Assembly

• Design and Assembly took approximately 4 months
• Coordination with Georgia Power, Coast Guard,
  Pilots Association
• Vendors involved
• ECO Oxygen Technologies (ECO2)
• Savannah Marine Services
• Godwin Pumps
• Air Liquide
• TIC
• Pro Electric
• YSI
• Pine Environmental
• Shaumbaugh and Sons

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Assembly
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Assembly
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Assembly
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Water Quality Monitoring

• 3 stationary nearshore monitoring stations
• GPA Berth 20 (near FR-04)
• Project Site (at TIC)
• USACE Dock (near FR-21)
• Monitoring 3 depths with a redundant sonde at
  each depth
• YSI 6920 (Optical DO sensor)
• Floating 1 m from surface
• Mid depth (based on mean low tide)
• Deep (1 m from the bottom)
• On-line real time data available

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Stationary Monitoring
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Water Quality Monitoring

• Weekly Synoptic Monitoring at Slack Tide
• Mid-channel Profiles
• 14 locations
• 4 depths
• 1 m from bottom
• 2/3 of the water column
• 1/3 of the water column
• 1 m form surface
• 56 measurements/profile

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Mid-Channel Profile
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Water Quality Monitoring

• Weekly Synoptic Monitoring at Slack Tide
• Horizontal transects (x-sections)
• 5 locations
• 5 points on each transect
• Overbank (river left facing upstream)
• Channel toe (river left facing upstream)
• Mid-channel
• Channel toe (river right facing upstream)
• Overbank (river right facing upstream)
• Multiple depths at each transect point
• 70 measurements/event

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Cross Channel Transects
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Water Quality Monitoring

• Far Field Slack Tide Monitoring
• 15 mile length
• 0.5 mile increments
• 3 depths
• 2 during system operation
• 2 post shutdown

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Long Run Mid-Channel Sampling Locations
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Dissolved Oxygen Deficit

• Oxygen saturation varies with temperature,
  pressure, and salinity
• The deficit is the difference between saturation
  and concentration
• Normalizes DO data accounting for temperature,
  pressure, and salinity changes
• The smaller the deficit the closer to saturation
  the actual concentration is
• Water Quality models use deficit

DOdeficit DOsaturation - DOconcentration
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Startup - GPA
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D.O. Deficit (mg/L) Low Tide (Longitudinal)8/6/
2007 (Background)
Average DO Deficit 3.91 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)8/11
/2007 (4-days Reoxygenation)
Average DO Deficit 3.72 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)8/20
/2007 (13-days Reoxygenation)
Average DO Deficit 3.30 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)9/4/
2007 (28-days Reoxygenation)
Average DO Deficit 3.56 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)9/6/
2007 (30-days Reoxygenation) (Clip)
Average DO Deficit 3.22 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)9/7/
2007 (31-days Reoxygenation) (Clip)
Average DO Deficit 3.26 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)9/25
/2007 (9-days Post Reoxygenation) (Clip)
Average DO Deficit 3.64 mg/L
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D.O. Deficit (mg/L) Low Tide (Longitudinal)9/26
/2007 (10-days Post Reoxygenation)
Average DO Deficit 3.90 mg/L
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Low-Tide Centerline Results
08/06/07
09/06/07
09/26/07
Average DO Deficit 3.90 mg/L
Average DO Deficit 3.91 mg/L
Average DO Deficit 3.22 mg/L
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DO Deficit Impact (Low Tide)

• DO deficit at startup Baseline 3.9 mg/L
• Average DO deficit Demonstration 3.3 mg/L
• DO deficit 10 days after shutdown 3.9
• Deficit Reduction Range (during operation) 0.7
  mg/L to 0.35 mg/L
• Average impact 0.6 mg/L over the three mile
  target segment

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High Tide Events
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Dye Test - Qualitative
Highest concentration of dye was noted at about
20 feet below the surface
55 gallons at 30 feet
5 gallons at the surface
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Project Challenges

• Schedule
• Wire burn out on VFD for pump 4 - 20 hours down
  on Cone 2 (8/16/07)
• O2 regulator seal blow out - cone 1 and 2 out 16
  hours (8/18/07)
• O2 ran out 2 times
• Intake screens fouled by growth periodic
  shutdown for cleaning, headloss over duration of
  the project
• Other outages

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Project Challenges Wildlife / Events
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Project Challenges Wildlife
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Project Challenges Other Events
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Project Challenges - Before and After
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Project Challenges - Before and After
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Demonstration System Limitations

• Injection at mid-depth
• Inefficient pumping system
• Significant headloss at end of project
• Wear of pumps
• Intake fouling
• Limited success at continuous measuring
  supersaturated DO concentrations at discharge

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Additional Activities and Conclusions

• Modeling
• Verification of the Savannah Harbor Model
• Comparison of field data to predicted results
• Conclusions
• The Speece Cone Technology was capable of
  mitigating for DO impacts that would be caused by
  deepening
• The Kings Island Turning Basin may be used as a
  DO capacitor
• The project improved water quality by reducing
  the DO Deficit an average of 0.6 mg/L

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Full Scale ReOxygenation Project

• Multiple locations for permanent systems
• Intakes would be designed to reduce headloss from
  fouling
• Vertical lift pumps to reduce headloss and
  provide sufficient pressures and flows
• May be distributed around the harbor and Back
  River
• Below ground installations in some areas
• Discharge as close to the bottom of the river as
  possible
• System may be demobilized in the fall and
  remobilized in the late spring

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Publicity
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SOCIETY OF MILITARY ENGINEERS SAVANNAH DISTRICT
MAY 8, 2008
GEORGIA PORTS AUTHORITY SAVANNAH HARBOR
REOXYGENATION DEMONSTRATION PROJECT
Questions?

• MACTEC Engineering and Consulting, Inc.