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US Army Corps of Engineers
BUILDING STRONG®
Saginaw Bay Sediment Separation
Pam Horner
USACE-Detroit
Richard A Price
ERDC-Vicksburg
Duluth, MN : 18-19 Nov 2014
SAGINAW RIVER, MI Project Location
SAGINAW RIVER, MI Project Description
formed by union of the Tittabawassee and Shiawassee Rivers 22 miles long flows northerly into the extreme inner end of Saginaw Bay, Lake Huron an entrance channel in the bay from the 27-foot contour in Saginaw Bay to
the river mouth (approximately 10 miles long); varying channel depths in the river ranging from 26 feet at the downstream
entrance, to 22 feet deep and 16.5 feet deep to the upstream limit at Green Point (not maintained) due to shallow depth)
five turning basins (one 25 feet deep at Essexville, one 22 feet deep on the east of the channel about one mile upstream from Cass Avenue in Bay City, one 20 feet deep at Carrollton, one 20 feet deep on the east side of the channel just upstream from the Sixth Street Bridge in Saginaw, and one 15 feet deep between the Bristol Street and New York Central Railway Bridges in Saginaw.
BUILDING STRONG®
BACKGROUND Project History
Original contaminant of concern – PCBs Levels ranged from non-detectable up to 25 ppm Contructed CDFs under 91-611 to contain
contaminated material PCB levels in river material declined over the years to
non-detectable New contaminant of concern - dioxins
0
10
20
30
40
50
60
70
80
90
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57
2004 %
Fin
es
Samples
Series1
0
10
20
30
40
50
60
70
80
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33
2008 %
Fin
es
Samples
Series1
Ave – 24 %
Grain Size
0 10 20 30 40 50 60 70 80 90
100
1 4 7 10 13 16 19 22 25 28 31 34 37
2011 %
Fin
es
Samples
Series1
Saginaw River Dredged Material Characteristics 1999-2011
Ave – 40 %
Ave – 39 % 0
10 20 30 40 50 60 70 80 90
1 3 5 7 9 11 13 15 17
1999 %
Fin
es
Samples
Series1 Ave – 47 %
Grain Size
BUILDING STRONG®
Saginaw River Dredged Material Characteristics - 2014
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
2014 %
Fin
es
Samples
Series1
Grain Size
BUILDING STRONG®
Saginaw River Dioxin Summary (TEQ ppt)
1999 2004 2008 2011 2014 Count 18 50 29 40 20
Min 2.1 0.0 1.6 4.9 3.9
Max 551.8 11,812.8 620.0 3,700.0 3,800.0
Ave 109.1 808.9 90.9 545.6 615.6
Std Dev 140.0 2,209.9 135.1 931.2 1,039.4
BUILDING STRONG®
Saginaw River 1999 Dioxin Data
0.0
100.0
200.0
300.0
400.0
500.0
600.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Dio
xin
TE
Q (
pp
t)
Sample Stations
Series1
BUILDING STRONG®
Saginaw River 2004 Dioxin Data
0.0
2,000.0
4,000.0
6,000.0
8,000.0
10,000.0
12,000.0
14,000.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
Dio
xin
TE
Qs (
pp
t)
Samples
Series1
BUILDING STRONG®
0.0
100.0
200.0
300.0
400.0
500.0
600.0
700.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
Dio
xin
TE
Q (
pp
t)
Sample Stations
Series1
Saginaw River 2008 Dioxin Data
BUILDING STRONG®
0.0
500.0
1,000.0
1,500.0
2,000.0
2,500.0
3,000.0
3,500.0
4,000.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Dio
xin
TE
Q (
pp
t)
Samaple Stations
Series1
Saginaw River 2011 Dioxin Data
BUILDING STRONG®
0
500
1000
1500
2000
2500
3000
3500
4000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Dio
xin
TE
Q (
pp
t)
Sample Stations
Series1
Saginaw River 2014 Dioxin Data
BUILDING STRONG®
0.0
2,000.0
4,000.0
6,000.0
8,000.0
10,000.0
12,000.0
14,000.0
1 6 11
16
21
26
31
36
41
46
51
56
61
66
71
76
81
86
91
96
101
106
111
116
121
126
131
136
141
146
151
156
Dio
xin
TE
Q (
ptt
)
Number of Samples
Series1
Saginaw River All Dioxin Data
BUILDING STRONG®
Saginaw River – Highest Dioxin Locations
BUILDING STRONG®
Saginaw River – Highest Dioxin Locations
BUILDING STRONG®
Saginaw River – Highest Dioxin Locations
BUILDING STRONG®
UPPER SAGINAW RIVER DMPF
BUILDING STRONG®
Upper Saginaw River DMPF
281 acres Holds 3.1 million CY Clay dikes (11 feet) Site underlain with clay and sand lenses Cutoff wall down 10 feet
BUILDING STRONG®
Issue Sandy dredged material
placed in the Saginaw DMDF has potential beneficial uses but contains unacceptable levels of dioxins
Previous testing of material has demonstrated uncertainty in actual concentrations and distribution
Core TEQ,
Pg/g
MDEQ Soil Standards
10-1 36.4 Res Particulate Soil - 71,000
10-2 17 Res Direct Contact - 90
10-3 5567 Non-Res Particulate – 59,000
10-4 213 Non-Res Direct Contact - 990
10-5 11
10-6 9.2
10-7 2282
10-8 410
10-9 171 Average - 901
10-10 299 Standard Deviation - 1777
Samples collected by USACE, Sep 2010
BUILDING STRONG®
Solution – Improve Analytical Results
Need less variability Need characterization of dioxin distribution
in sediment fractions Need separation of dioxin from beneficial
sand
BUILDING STRONG®
Approach Sample cores over entire
exposed sediment surface
Characterize each core for particle size and presence of carbon (wood, coal, coke, etc)
Composite cores based on these characteristics
Improve analytical results by careful processing of samples
BUILDING STRONG®
Sampling Methods
Electric hammer drill was used to collect cores to a depth of 40 inches.
BUILDING STRONG®
Sample Preparation A sample of each mixed core was collected and placed in a 120ml
amber glass jar. The samples were dried in an oven at 42 deg C for 72 hrs. A 40-gram sub-sample was removed and lightly crushed in a mortar
to reduce aggregates The sample was then sieved through ASTM # 4 (4.76mm), #40
(0.42mm) and #200 (75um). The various fractions were weighed separately to determine % of
total mass. The remaining sample was ground in the mortar to ensure light
black carbon particles were thoroughly mixed and a subsample was collected from each and submitted for Total Carbon analysis.
BUILDING STRONG®
Sample Processing
A subsample of each core was characterized based on grain size and composition. Cores were composed mostly of fine to medium sand between 74 and 420um. Coarser and finer grained particles were either silt/clay, pebbles and varying sizes of black carbon.
Separation of lighter density carbon vs silica sand during the sieving process following grinding in a mortar. Sample was ground until all passed a 250um sieve.
BUILDING STRONG®
Particle Size Distribution, % (separately shown for 2 placement
operations)
0.0
20.0
40.0
60.0
80.0
100.0
1A 1B 1C 1D 1E 2A 2B 2C 2D 2E 3A 3B 3C 3D 3E 4A 4B 4C 4D 4E 5A 5B 5C 5D 6A 6B 6C 6D
>4.76mm
<4.76mm
<0.42mm
<75um
0.0
20.0
40.0
60.0
80.0
100.0
7A 7B 8A 8B 9A 9B 10A 10B 11A 11B 12A 12B 12C 13A 13B 13C 14A 14B 14C
>4.76mm
<4.76mm
<0.42mm
<75um
BUILDING STRONG®
Total carbon, %
0
0.5
1
1.5
2
2.5
3
1A 1B 1C 1D 1E 2A 2B 2C 2D 2E 3A 3B 3C 3D 3E 4A 4B 4C 4D 4E 5A 5B 5C 5D 6A 6B 6C 6D
1st year deposit
Total C, %
0
0.5
1
1.5
2
2.5
7A 7B 8A 8B 9A 9B 10A 10B 11A 11B 12A 12B 12C 13A 13B 13C 14A 14B 14C
2nd year deposit
Total C, %
BUILDING STRONG®
Dioxin Analysis Cores were composited into three distinct particle size/TOC based
samples. These are described as: ► Sand – mostly fine to coarse sands with some larger fragments
of shell, rock and coal/coke ► Fine – mostly fine to moderate sands with silt, clay and fine
organics ► Carbon – mostly sand with elevated levels of organic carbon,
primarily wood debris These composites prepared for analysis as follows:
► lightly crushed to pass a 2mm screen and analyzed as 2mm sized fraction.
► ground using a mortar and pestle to completely pass a 250um screen.
Purpose: Demonstrate the variability due to selective particle bound
contamination
BUILDING STRONG®
Dioxin TEQ Results
TEQ WHO2005 ND=0.5,pg/g AVG STDEV DEV/AVG
Sand 250um 505 510 514 489 555 514.60 24.50 0.05
Sand 2mm 51.8 113 106 79.4 197 109.44 54.58 0.50
Fine 250um 860 1080 906 1410 866 1024.40 233.41 0.23
Fine 2mm 564 1190 727 944 219 728.80 369.48 0.51
Carbon
250um 829 788 1140 1040 839 927.20 153.95 0.17
Carbon 2mm 1030 620 471 936 4880 1587.40 1854.62 1.17
TEQ WHO2005 ND=0.5,pg/g AVG STDEV DEV/AVG
Carbon NS NS NS 21,517.8 19,428.1 20,473.0 54.58 0.50
Fine NS NS 1,806.2 1,877.0 1,940.1 1,874.6 233.41 0.23
Sand NS NS 62.1 114.5 164.0 113.6 51.96 0.45
Sand
Washed 2.1 2.0 1.9 2.6 2.5 2.3 0.297 0.13
Core Composites
Separated Fractions
BUILDING STRONG®
Options and Path Forward
Washing sand can significantly reduce dioxins to acceptable levels and render suitable for recovery and beneficial use
Pilot scale project to evaluate effectiveness during dredging and/or pumping operations
Consider implications of dioxin laden residuals ►Removal for disposal ►Allow settling in pond and cap
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