Transcript Sepetiba Bay - CEDA conferences

Sepetiba dredging and reclamation works
CEDA dredging days – October 2008
Session 5: Dredging in sensitve areas
Date: 2 Oct 2008
Time: 10:50 – 11:10
Author: Jeroen Gheysens
CEDA dredging days Oct 2008
1
Sepetiba dredging and reclamation works
Overview
•
•
•
•
•
Main project information
Dredging in sensitive areas
Environmental monitoring
Dredging of contaminated materials
Reclamation area layout
CEDA dredging days Oct 2008
2
Sepetiba dredging and reclamation works
Geographical Location
RIO DE JANEIRO
SÃO PAULO
BRAZIL
SEPETIBA BAY
Reclamation Area
Dredging Area
CEDA dredging days Oct 2008
3
Sepetiba dredging and reclamation works
General Info on Project
• CLIENT:
ThyssenKrupp CSA Companhia Siderúrgica
• CONTRACTOR:
Consorcium Dredging International nv – Boskalis
International bv
• EXECUTION PERIOD
September 2006 – April 2008
CEDA dredging days Oct 2008
4
Sepetiba dredging and reclamation works
RECLAMATION
AREA
• Access Channel
–
–
–
–
Length 4,3km
DREDGING AREA
Bottom width 128m
Dredging depth -14,5m CD
Volume 6.600.000 m³
• Harbour Basin
– Turning circle 250m
– Dredging depth -14,5m CD
– Volume 4.500.000 m³
CEDA dredging days Oct 2008
5
Sepetiba dredging and reclamation works
• Boosters
– Cosel:
– DI 509:
– Nieuwe Merwede:
5.500 kW
4.475 kW
2.984 kW
• Large Cutter Suction Dredger (CSD)
– Vlaanderen XIX:
8.358 kW
CEDA dredging days Oct 2008
6
Sepetiba dredging and reclamation works
• Confined Disposal Facilities
– CDF 1 135.000 m³
– CDF 2 141.000 m³
• Contaminated Material
– Volume 131.000 m³
• Capping Material
Contaminated Areas
– Volume 54.000 m³
CEDA dredging days Oct 2008
Capping Areas
7
Sepetiba dredging and reclamation works
• Environmental CSD Beaver St. Lawrence
– Cutter Power: 171 kW
– Pump Power: 839 kW
CEDA dredging days Oct 2008
8
Sepetiba dredging and reclamation works
Overview
•
•
•
•
•
Main project information
Dredging in sensitive areas
Environmental monitoring
Dredging of contaminated materials
Reclamation area layout
CEDA dredging days Oct 2008
9
Sepetiba dredging and reclamation works
Dredging in sensitive areas
• Sepetiba Bay: historical contamination, mainly
heavy metals – Mangroves - Fishery
• Environmental effects
–
–
–
–
Spreading and settlement of resuspended solids
Impact on soil organisms during operation
Alteration of bathymetry
Changing shoreline configuration
MINIMISE THE ENVIRONMENTAL EFFECTS!
CEDA dredging days Oct 2008
10
Sepetiba dredging and reclamation works
Dredging in sensitive areas
• Minimise the environmental effects
– Understand the environmental situation and identify
the most sensitive areas
– Selection of dredging equipment
– Identification of environmental impacts
– Selecting the most appropriate working method
– Well trained, experienced and environmental aware
crew
– Environmental management and monitoring plan
CEDA dredging days Oct 2008
11
Sepetiba dredging and reclamation works
Overview
•
•
•
•
•
Main project information
Dredging in sensitive areas
Environmental monitoring
Dredging of contaminated materials
Reclamation area layout
CEDA dredging days Oct 2008
12
Sepetiba dredging and reclamation works
Environmental Monitoring
• Water quality monitoring
– Suspended solids dewatering < 500mg/l
• Capping of CDF’s
– Capping layer of 1m with ‘no contamination’
• Noise level monitoring
– < 65dB (background level)
CEDA dredging days Oct 2008
13
Sepetiba dredging and reclamation works
Environmental Monitoring
• Baseline monitoring
– Identification of the situation before the start of the
works
– Relationship turbidity – suspended solids
• Background monitoring
– Weekly basis (background locations)
– Identify turbidity from other sources
• River discharges
• Heavy rainfall
• Seasonal fluctuations
CEDA dredging days Oct 2008
14
Sepetiba dredging and reclamation works
Environmental Monitoring
• Water quality monitoring
– Daily measurements at fixed locations
•
•
•
•
Turbidity (~ Suspended Solids)
Water temperature
Salinity
Instrument Depth
RECLAMATION
AREA
DREDGING AREA
CEDA dredging days Oct 2008
15
100
200
90
180
80
160
70
140
60
120
50
100
40
80
30
60
20
40
10
20
0
0
1
2
Santa Cruz
3
4
5
6
Piraí
7
8
9
C10
precipitation (mm)
turbidity (NTU)
Sepetiba dredging and reclamation works
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
days
C18
CONAMA Limit for Freshwater
Baseline from S. Fransisco Rv
• Fixed points in the river São Francisco
• TSS (mg/l) = 1,14 NTU
CEDA dredging days Oct 2008
16
Sepetiba dredging and reclamation works
45
200
40
180
160
35
turbidity (NTU)
120
25
100
20
80
15
60
10
40
5
20
0
0
1
2
3
4
precipitation
5
6
7
C20
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
days
C30
C40
C50
Baseline from Sepetiba Bay
• Fixed points in the Sepetiba Bay
• TSS (mg/l) = 2,74 NTU
CEDA dredging days Oct 2008
17
precipitation (mm)
140
30
Sepetiba dredging and reclamation works
35
200
180
30
160
140
120
20
100
15
80
60
10
40
5
20
0
0
1
2
3
precipitation
4
5
6
D2N
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
days
D2S
D2W
D2E
D3N
D3S
D3W
D3E
• Points around the dredger
• TSS (mg/l) = 2,74 NTU
CEDA dredging days Oct 2008
18
precipitation (mm)
turbidity (NTU)
25
Sepetiba dredging and reclamation works
Overview
•
•
•
•
•
Main project information
Dredging in sensitive areas
Environmental monitoring
Dredging of contaminated materials
Reclamation area layout
CEDA dredging days Oct 2008
19
Sepetiba dredging and reclamation works
• Confined Disposal Facilities
– CDF 1 135.000 m³
– CDF 2 141.000 m³
• Contaminated Material
– Volume 131.000 m³
• Capping Material
Contaminated Areas
– Volume 54.000 m³
CEDA dredging days Oct 2008
Capping Areas
20
Sepetiba dredging and reclamation works
Dredging of contaminated materials
•
•
•
•
Minimise spillage, turbidity and turbulence
Minimise storage by high concentration dredging
Minimise noise and unpleasant smells
Optimise precision for accurate and selective thin
layer dredging
CEDA dredging days Oct 2008
21
Sepetiba dredging and reclamation works
Dredging of contaminated materials
Environmental Sweep Dredger
vs
Environmental Disc Cutter
CEDA dredging days Oct 2008
22
Sepetiba dredging and reclamation works
Overview
•
•
•
•
•
Main project information
Dredging in sensitive areas
Environmental monitoring
Dredging of contaminated materials
Reclamation area layout
CEDA dredging days Oct 2008
23
Sepetiba dredging and reclamation works
Reclamation area layout
• Mangroves (high environmental sensitive area)
– Protect from salt water of the dredging process
– Risk of bund wall failures (Monitoring!)
• Reduce suspended solids dewatering
– Maximise travel distance of water on the area
– Weir boxes (managing water levels on the area)
– Monitoring!
CEDA dredging days Oct 2008
24
Sepetiba dredging and reclamation works
CEDA dredging days Oct 2008
25