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OCR for page 239
DEVELOPMENTS IN EQUIPMENT DESIGNED FOR HANDLING
CONTAMINATED SEDIMENTS
John B. Herbich
Texas A&M University
ABSTRACT
Conventional dredging equipment typically handles large
volumes of material in maintaining or deepening navigational
channels. Such equipment may be operated in a modified pro-
cedure to handle relatively small volumes of contaminated
material. However, in some cases, it may be more appropri-
ate to use special purpose dredges (either specially devel-
oped, or adapted), which are more suitable for handling con-
taminated sediments. Several special purpose dredges are
described and their capabilities discussed.
INTRODUCTION
The selection of proper dredging equipment for any project is impor-
tant to achieve an efficient operation (Andrassy and Herbich, 1988~.
In the case of contaminated sediments, it is even more important since
any additional contamination generated during dredging must be avoided.
Selection depends on a number of factors:
1. characteristics of sediments,
2. quantity of sediments to be removed,
3. degree of contamination,
4. toxicity of contaminants,
5. location,
6. environmental conditions
etc.),
7. distance to the disposal site,
8. type of disposal, and
9. availability of particular equipment
location,
environmental conditions at the site (waves, currents, tides,
There are several types of dredges for conventional operations
designed principally for moving large volumes of material efficiently.
Conventional equipment operated in a modified procedure can be effec-
tive, as reported by Hayes et al. (1988~; however, in some cases it
may be more appropriate to use special purpose dredges (either
developed or adapted) suitable for handling contaminated sediments.
239
OCR for page 240
category:
3.
240
There are several dredges that may be placed in a special purpose
1. mechanical--enclosed clamshell;
2. mechanical-hydraulic--Mud Cat, remotely controlled Mud Cat, and
Clean-up system;
hydraulic--Refresher, waterless, matchbox, and wide sweeper,
cutterless dredge; and
4. pneumatic--Pneuma and Dozer.
MECHANICAL DREDGES
Enclosed Clamshell
The Japanese have developed a watertight clamshell for use with
grab bucket dredges. An evaluation of the watertight bucket was made
by the U.S. Army Engineer Waterways Experiment Station in 1982 (Figure
11. Experiments conducted at the Jacksonville District indicated that
the watertight bucket significantly reduced water column turbidity and
did not reduce production.
Figure 2 shows the benefit of using an enclosed bucket. Operation
of the dredge can be modified slightly to reduce sediment resuspension
by slowing the raising and lowering of the bucket through the water
column. It must be noted that this operation modification reduces the
production rate of the dredge, and generally high unit costs are associ-
ated with this type of mechanical dredging.
1 Comer
~ Cover
~ .She1 1
FIGURE 1 Open and closed positions of the watertight clamshell
bucket. SOURCE: Hayes et al., 1984.
OCR for page 241
24i
300
-
Cat 200
o
Oh
By
AL 1 00
Oh
O
\
0 200
Open Clamshell
___ Enclosed Clamshell
\
-
_~
I cram I ~ = I
400 600 800
DISTANCE FROM DREDGE, FT
FIGURE 2 Resuspended sediment levels from open and enclosed clamshell
dredge operations in the St. John's River. SOURCE: Hayes, 1986.
MECHANICAL HYDRAULIC DREDGES
Mud Cat
The Mud Cat has a horizontal Butterhead equipped with knives and
spiral augers that cut the material and move it laterally toward the
center of the augers where it is picked up by the suction (Figure 3~.
The dredge can remove sediments in a 2.6-m width and in water depths up
to 4.9 m. The dredge operates on anchor cables, and the manufacturer
claims that it leaves the bottom of the dredged area flat and free of
windrows characteristic of typical cutterhead and hopper dredge
operations.
l '_' I',~n ~ '_ al _
- -
FIGURE 3 the Mud Cat--notice that the cover is lifted to show two
augers .
OCR for page 242
242
By covering the cutter-auger combination with a retractable mud
shield the amount of turbidity generated by Mud Cat's operation can be
minimized.
Remotely Controlled Mud Cat
A remotely controlled unit has been developed in which the control
cab is located on land and is remotely connected to the Mud Cat by an
umbilical cord. This allows dredging of hazardous or toxic materials.
The remote control provides the shore-based dredge master with a vari-
able traversing winch control, a variable auger control, a variable
dredge pump speed control, and a manually controlled emergency shut
down . The usual instrumentation is also displayed in the control cab
and visual alarms are provided.
Clean-up System
To reduce or minimize resuspension of the sediment, Toa Harbor
Works, Japan has developed a unique Clean-up system for dredging highly
contaminated sediment (Herbich and Brahme, 1988; Sato, 19849. The
Clean-up head consists of a shielded auger that collects sediment as
the dredge swings back and forth and guides it toward the suction of a
submerged centrifugal pump (Figure 4~. To minimize sediment resuspen-
sion, the auger is shielded and a moveable wing covers the sediment as
it is being collected by the auger. Sonar devices indicate the topo-
graphy of the bottom. An underwater television camera also indicates
the amount of material being resuspended during a particular opera-
tion. Figure 5 shows details of a shielded auger (Sato, 1984~. Fairly
large volumes (2.2 million ~ up to 1981) have been excavated by
Clean-up dredges in soft muds and sand containing various contaminants
such as mercury, cadmium, PCBs, oily and organic substances. Table 1
summarizes the specifications of Clean-up dredges.
Pro plump ~ ~
Crow Of SWIM
,':1` , CC~HLaL - CD 1 -
WINC: Ji - HER
~ ~ ~ ~ BOr~ SEDI~t~
~////~//////////~/~//D/~///~//~
FIGURE 4 The Clean-up system. SOURCE: Sato, 1984.
OCR for page 243
243
FIGURE 5 Clean-up shielded
auger head. SOURCE: Sato, 1984.
~—l~
Performance of various Clean-up dredges between 1973 and 1981 is
summarized in Appendix A.
HYDRAULIC SUCTION DREDGES
Refresher
The Refresher dredge was developed purposely for removal of contami-
nated materials by a Penta-Ocean Construction Company, Ltd. (Shinsha,
1988~. The dredge material is confined by a specially designed flex-
ible enclosure that completely covers the cutter, preventing escape of
sediments to the outside of the immediate dredging area (Figure 6~.
The working open section is always on the swing side of the cutter-
head. A gas removal system is also installed and can be activated as
needed to prevent gas moving up the section pipe. The flexible enclo-
sure of the Butterhead is automatically adjusted to bottom contours.
-~,~
SIDEVIEW OF LADDER
FIGURE 6 Refresher dredge. SOURCE: After Shinsha, 1988.
FRONT VIEW
OCR for page 244
244
General Specif ications
The Refresher dredge is equipped with the main pump and an addi-
tional pump on the ladder to provide a high level of production. Auto-
matic valves in the suction pipe prevent sediment-water mixture from
flowing back in case of power failure (Figure 7~.
Refresher No. 3 and Mini-Refresher Tokyo Maru specifications
are given in Table 2. Pump specifications for both the ladder pump and
the main pump are given in Table 3.
Waterless Dredge
Waterless Dredging Company developed a dredging system in which the
cutter and centrifugal pump are enclosed within a half-cylindrical
shroud. By forcing the Butterhead into the material, the cutting
blades remove the sediment near the front of the cutterhead with little
entrainment of water. According to the manufacturer, this waterless
system is capable of pumping slurry with a solids content of 30 to 50
percent by weight with little generation of turbidity. The dredge
pipeline sizes range from 15 to 30 cm. The waterless dredge
development is relatively new and and experience with it is quite
limited.
PIPELINE ANT l-BACK F LOW
~ OUTLET VALVE
/ , ~
r 7? / DIRECTIONAL
\ /_ ~ =\ \ ON
eBoAARDG'NEG ~ ~` _ \
ON BOARD \ \
NON-POLLUTING SYSTEM MONITORING
SOUND MONITOR FOR DREDGING THICKNESS
`~ 11
I MONITOR MUD
PUMP \ \ I RECORDER
DIRECTIONAL ~ \ \
VALVE
WINCH I IVI~^L
\ TV E
~4
LADDER PUMP
\ '< SUCTION PIPE
/ \ MUD-MEASURING
FIGURE 7 Description of
a Refresher dredge.
SOURCE: Shinsha, 1988.
DIRECTIONA DE
VALVE ~ \ \ /
ANTI-BACKFLOW INTAKE VALVE TV CAMERA
HYDRAULIC CYLINDER
MOVABL ~ COVER ~~\
- HEAD —~ ~ CTOR
. . . . . .
. . .
OCR for page 245
.
-
.~!
E
.~_
ti if
~ C
-
_
D
3
0
o
. -
.1
em
L)
-
.Ea
X
X
245
~ I~! !~34 !~i Iiit
o ~ ~
0 ~ 0 ~ 0 ~ 0 ,. ° In
~~ ~~ Hm 8- 8-
o o o o o
o o o o o
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o o o o o
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o
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~ ~ ji~ Eli it to
mX ~ ax o ma X X
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'i ~ a
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c~
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En
·.
OCR for page 246
246
TABLE 2 General Specifications for
the Refresher Dredge.
GENERAL SPECIFICATIONS
MINI REFRESHER
REFRESHER NO. 3
TOKYO MARU
.
SHIP DIMENSIONS
( LxBxD)
DISPLACED
TONNAGE
DISPLACED
DEPTH
DISCHARGE
DISTANCE
1
OR EDG I NG
CAPAC ITY
_
MAXIMUM
OR EDG ING DEPTH .
45.60x13.50x3.30 m
1,200 t
2.20 m
BARG E ~3.000m
LOADING
150 ~ 400m3/h
.
20 m
SOURCE: After Shinsha, 1988.
TOKYO MARU
17.00x6.40x1.35 m
80 t
0.80 m
ARGE ~ 500 m
LOAD I NG
50 ~120m3/h
7.5 m
_
Matchbox Dredge
TABLE 3 Pump Specifications for
Refresher No. 3 and Mini-
Refresher Tokyo Maru Dredges.
.
CL
G
m
Z
0
. _
. MODEL
_
RATED
HORSEPOWER
PUMPING
CAPAC ITY
PUMPING
HEIGHT
MODEL
RATED
HORSEPOWE R
PUMPING
CAPAC ITY
PUMPING
HEIGHT
PUMP SPECIFICATIONS
REFRESHER NO. 3
CENTRIFUGAL TYPE
150PS
_ .
800 ~ 2,000 m3/h
. .
10 ~ 20m
· .
CENTR I FUGAL TYPE
I.
1,800PS
it,
800 ~ 2,000 math
l
20 ~50
SOURCE: After Shinsha, 1988.
A special suction head was developed by a dredging contractor in
the Netherlands to replace the traditional Butterhead (d 'Angremond et
al., 1984~. The main design points are as follows (Figure 8~:
MINI REFRESHER
TnKyo MARU
. _ _
1
CENTRIFUGAL TYPE
_
100PS
250 ~ 600 m3/h
11 - 1 5 m
CENTRIFUGAL TYPE
1 50PS
250 ~ 600 m3/h
10~ 35m
1. A large plate covers the top of the dredge head to avoid inflow
of water and escape of gas bubbles.
2. Adjustable angle between the drag head and the ladder to create
an optimum position of the drag head independent of the dredging
depth.
3. There are openings on both sides of the drag head to improve
dredging efficiency. During swinging action the leeward side is
closed to prevent water inflow.
4. Dimensions of the head must be carefully designed for the
average flow rate and swing rate (Figure 9~.
A diffuser may be installed at the submerged end of the discharge pipe
to reduce the dispersion of fine sediment in the water column (d'Angre-
mond et al., 1984; Neal et al., 1978~. By its gradually widening cross
section, the flow could decelerate to an acceptable velocity to reduce
turbulence. Outflow velocities are designed to be between 0.2 to 0.3
m/see (Figure 10~; however, it is unlikely that contaminated material
would be discharged in open water. A possible application may be to
employ such a diffuser in a containment area. A degassing system is
also installed to prevent or reduce the amount of gas moving up the
suction pipe.
OCR for page 247
247
/
an- ~—.- . ;,_
At, -
_- ~ ~ ;.
i'
· I 61 " ~ 'I
8 1
laid ~ LULL O~
DutL-h d~s.~-1 OWL; su"-tic`~ 8~ p To acme
sedun~~nts-~it8'~ a snu~n of rcsuspens~r~. Suitable For
unnail v~"s~u;:S o'- ;lea'~u,? jobs lo fu``d). klun~ts
Faust ~ ~. ~~ ;.~`s~s~n~,re~t~ ~t,8 ,~ free
8l'`;~8,,~r ~8;t.`t .
~LL-L-bJ ~~
Dorm b4WEb D`lt.1l built.~..t Al ELF all; t;`,- ;~`,lt-~.~i aquatic
d`~pc`:;al(;appin`~) 1~ this luff ot dis~>~al the -"b..~c,~.1 . ffusu
all1 s a ~l~.t placc,~l~rit of poll~lt~ ;.1~i~~s Tail ~ In
pit Diffuser is theft Used to plum- ~ `.~.' 1~;' ~ cap of ~lca'
nix ~ Trill to ~sscr`tiall`~ scat us taut polt``ta`~ts .
o
- -
L4, Ail
FIGURE 8 Dutch Matchbox dredge. SOURCE: After IJ. S . Army Engineer
District, Chicago .
i'
FIGURE 9 Schematic of Matchbox
suction head. SOURCE: After
d'Angremond et al ., 1984 .
{_,~
OCR for page 248
248
r
l
1
Io
Ant
1~:''r '-, he
:2~ 22QO
.
.1
FIGURE 10 Schematic of diffuser (all dimensions are in millimeters).
SOURCE: d'Angremond et al., 1984.
TABLE 4 Plume Area for 10-mg/liter Contour for
the Cutterhead, Clamshell, and Matchbox Dredges.
Depth
percent
Cutterhead Clamshell Matchbox
acres acres acres
50
80
95
SOURCE: Hayes et al., 1988.
0 1.7 0
0 1.8 0
0 --- 0.4
1.2 3.5 2.95
A direct comparison between a Matchbox suction head and a conven-
tional butterhead was made by the Waterways Experiment Station in
Calumet Harbor (Hayes et al., 1988~. The Matchbox was specifically
designed to be fitted on the ladder of the U.S. Army Corps of Engi-
neers' dredge Dubuque . The Calumet Harbor demonstration indicated
that the clamshell dredge generated the largest suspended sediment
plume affecting the entire water column. The butterhead slightly
outperformed the Matchbox dredge as shown in Table 4.
Wide Sweeper Cutterless Dredge
Wide Sweeper No. 6 hydraulic suction dredge does not have a cutter
and is principally employed for removal of contaminated materials
without resuspending the sediment particles (Shinsha, 1988~. The main
OCR for page 249
249
features of Wide Sweeper are that
1. bottom sediments can be removed essentially without resuspen-
sion of particles,
2. acoustic sensors determine the characteristics of sediment to
be dredged,
3. the suction head can follow seabed configuration to some ex-
tent, or can be kept in a horizontal position,
4. turbidity generated is monitored by a television camera, and
5 the dredge is equipped with a ladder pump and a main pump.
General specifications are shown in Table 5.
Figure 11 shows the general arrangement of the suction head.
TABLE 5 General Specifications of Wide Sweeper No. 6
Name of Hull
Ship Type Dimensions Main Pump Ladder Pump Including
"Wide Diesel Length: 58.2m 3,200 PS, 950 PS, Single- Sludge
Sweeper Electric Breadth: 14m Single-stage, stage. Single- observation
No. 6" Depth: 3.7m Single-suction. Suction. system
Draft: 2.3m Centrifuge type Centrifuge type Operation
SOURCE: Shinsha, 1988.
control system
T 0~
I'm ~~F
.: ~
~ _
C' Direction of swing
FIGURE 11 General arrangement of the suction head on dredge Wide
Sweeper No. 6. SOURCE: Shinsha, 1988.
OCR for page 251
251
is applied during the cylinder- filling stage when the hydrostatic pres -
sure is not sufficient to rapidly fill the cylinders. The pump is
usually mounted at the end of a ladder and equipped with special suc-
tion heads and cutter units depending on the type of material being
dredged. The conditions around the dredging system, such as thickness,
bottom elevation after dredging, and amount of resuspension, are moni-
tored by high-frequency acoustic sensors and an underwater television
camera. A large Dozer pump has a dredging capacity ranging from 300 to
500 m /fur. During one dredging operation, suspended solids levels
within 3 m of the dredging head were all within background concentra-
tions of less than 6 mg/liter. Figure 13 is a sketch of the oozer
dredge; Figure 14 describes the ooze dredging system DREX, consisting
of a suction mouth and a device that permits a back and forth movement
of the suction mouth. This modified system is said to increase solids
concentration up to 60 percent.
,
I hi
FIGURE 13 Outline of
oozer dredge ~ dimens ions
4 ooze collecting tan
are In m~lllmeters).
SOURCE: Herbich and Brahme, ' clear
1988 .
FIGURE 14 Sketch of
oozer dredging system.
SOURCE: Herbich and
Brahme, 1988.
s'~ctlon couth 2 pump 3 "gnctic [low-meter
5 drt~ring DC motor 6 test soil
8 carriage 9 rail
\\\ \\
~ adds
t~rdrsut is aoto'
tr'~-'
1'
~ move
~ u
OCR for page 252
252
The main features of the oozer dredge are as follows:
1. The dredge can effectively remove contaminated sediments from a
maximum depth of 18 m.
. Since the swing speed can be adjusted from 0 to 20 m/min, the
dredge can be effective in removing suspended sediments.
. Five acoustic sediment sensors can measure the bearing pressure
of sediment to be removed and the thickness of various sediment
layers.
4. Underwater television cameras monitor the presence of turbidity
near the suction intake.
Toxic gases released during dredging pass through gas scrubbers
to remove toxic content before gases are released to the
atmosphere.
6. A screen is located at the suction mouth to prevent large ob-
jects from entering. Double-suction valves and electrically
controlled check valves provide secondary protection.
7. Dozer dredges can, under ideal conditions, pump sediments at in
situ density.
8. Different cutters and suction heads are available for dredging
sediments ranging from clay to sand.
5.
Specifications for oozer dredge Taian Mare are given in Table 6
and her performance between 1974 and 1980 is listed in Table 7.
RESUSPENSION LEVELS OF SEDIMENT FOR SPECIAL PURPOSE DREDGES
The special purpose dredges that appear to have the most potential
in limiting resuspension are shown in Table 8.
SUGARY
Conventional dredging equipment may be operated in a modified
procedure to handle contaminated material. A decision about whether to
use modified equipment should be made on economic grounds. Several
special purpose dredges were developed, principally overseas, and have
been successfully employed in removal of contaminated sediments.
Capabilities of mechanical, mechanical-hydraulic, and hydraulic suction
dredges are summarized in Tables 9, 10, and 11. Capabilities of
pneumatic dredges are shown in Table 12.
ACKNOWLEDGMENTS
This symposium paper was reviewed by Mr. Charles C. Calhoun, Jr.,
Assistant Chief, Coastal Engineering Research Center (CERC), U.S. Army
Engineer Waterways Experiment Station, and by Dr. Cliff L. Truitt,
CERC. Their comments were appreciated.
OCR for page 253
253
TABLE 6 Specifications of Dozer Dredge Taian Maru
Hull:
Engine:
Winch
Overall length
Breadth ......
Depth .
Draft ...
Dredging depth
...·····~····-
m
12 m
3 m
2.2 m
17 m
1
Type: Cylindrical twin-barrel, negative pressure suction and
positive pressure discharge.
Dredging capacities (Pressure intensity: 7kg/cm2)
Discharge Pumping
Density distance production
(%) (m) . (m /h)
60 100 580 350
60 500 500 300
60 1,000 420 250
Discharge pipe: 450 A
Air compressors .........
Dredging
production
(m /h)
3
Type: Screw rotary system 2
Capacity: 34.2 m /min x 7 kg/cm x 1,770 r.p.m.
Driving generator: 190 KW x AC 440 V x 60 Hz x 4P
Vacuum pump a~ em 1
Type: Roots system 3
Capacity: -400 mmHg x 44.8 m /min
Driving generator: 110 KW x AC 440 V x 60 Hz x 6P
Main generator
Type: Horizontal drip -proof rest self - excite
Capacity: 450 KVA x 3 0 x 60 Hz x 445 V x 8P
Continuous output: 5 30 ps x 900 r . p . m .
Ladder winch: 12T x 24 m/min x 75 KW x 6P 1
Swing winch: 15T x 0-12 m/min x 70 KW 1
Spud winch: 12T x 17 m/min x 50 KW x 6P 1
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254
TABLE 7 Performance of Dozer Dredge Taian Maru
Undisturbed Volume of
Construction Soil Moisture Deleterious Dredging
Place Period Condition Content (X) Material Soil (m ) Treatment
Iyo-Mishima April-May Sandy silt 144 Pulpwood 30,000 Direct discharge
Ehime Pref. 1974 length 356 m
Natural sedimentation
No treatment of
return flow water ~
-Do- July 1974 -Do- 400 - 800 -Do- 27,000 Direct discharge length
356 m 1000 m
Natural sedimentation
No treatment of return
flow water
Chiba Port January- June Silt 300 - 400 Be, Pb 40,800 Transport with barge
Chiba Pref. 1975 Secondary pumping
! with centrifugal pump
Natural s:.dimont~1~.i On
Takasa8°
Port
Hyogo Pref.
August -
December
1975
Sandy silt 150 - 200 PCB 224,816
Direct discharge length
300-1,20G m
Solidity
Removal of deleterious
material
Direct discharge length
460 m
Natural sedimentation
Removal of deleterious
_ material
Direct discharge length
300-800 m
Natural sedimentation
Removal of deleterious
mater) at
Sakaide Port July- Silt 90 - 100 He
Kagawa Prep. September
1975
14,000
Iwakunt Port
Yamaguchi
Pref.
January-
February
1976
Sandy silt 100 - 200 Pulpwood 31,Q00
Tokuyama Port July-
Yamaguchi December
Pref. 1976
Sandy silt SO ~ 300 Be 128, 16Q
Transport with barge
Natural sedimentation
Removal of deleterious
material
Transport with barge
Natural sedimentation
Removal of.deleterious
material
Discharge with booster
pump
Natural sedimentation
Removal of deleterious
__ material
-Do-
Dec~mbor 1976- Sandy silt
March 1877
SO - 300 B., C6814 82,000
Yokkaichi
Port
Mie Pref.
April 1977- Sandy silt
February 1978
280 -500 He 655,000
Mizush~ma July- Silt 40 - 100 C6H14 92,800 Transport with barge
Port September Natural sedimentation
Okayama Pref. 1978 Removal of deleterious
material
Osaka Bay March 1980 Silt 150 - 250 Organics 6,000 Pilot Corks
HYORO Pref. - --- --
Yokkichi Port June 1980 Silt lS0 -Do- 44.000 Excavation of ses bed
OCR for page 255
255
TABLE 8 Resuspended Sediments by Special Purpose Dredges
Dredge
Reported suspended sediment concentrationsa
Pneuma pump 48 mg/liter, 3 ft above bottom
4 mg/liter, 23 ft above bottom (16 ft in front
of pump)
Clean-up system 1.1 to 7.0 mg/liter above suction
1.7 to 3.5 mg/liter at surface
Dozer pump Background level (6 mg/liter), 10 ft from head
Refresher system 4 to 23 mg/liter, 10 ft from head
NOTES:
aSuspended solids concentrations were adjusted for background
concentrations.
SOURCE: Herbich and Brahme, 1988.
TABLE 9 Summary Table of Mechanical Dredges
Depth Resuspens ion
Type Production limitation of sediment Comments
Open clam-
shell
bucket Low
Watertight Low
clamshell
bucket
30-40 ft High
30-40 ft Low
Experiments
conducted in
the St. John' s
Rearer
OCR for page 256
256
TABLE 10 Summary Table of Mechanical-Hydraulic Dredges
Depth Resuspension
Type Production limitation of sediment Comments
Mud Cat Moderate 15 ft Low to Extensively
moderate used
Remotely Low 15 ft Low to New develop-
controlled moderate ment
Mud Cat
Clean-up Moderate 70 ft Low to Extensively
system moderate used in
Japan
TABLE 11 Summary Table of Hydraulic Suction Dredges
Depth Resuspension
Type Production limitation of sediment Comments
Refresher Moderate 60-115 ft Low Extensively
to high used in Japan
Waterless Moderate Low Limited
experience
Moderate 85 ft Low Experiments
to high conducted at
Calumet Harbor
Wide Moderate 100 ft Low Used in Japan
Sweeper
TABLE 12 Summary Table of Pneumatic Pumps (Dredges)
Depth Resuspension
Type Production limitation of sediment Comments
Pneumatic Low to +100 ft Low
moderate
Evaluated by COE
Waterways Experi
ment Station
Dozer Moderate 59 ft Low Used extensively
to high in Japan
OCR for page 257
257
REFERENCES
Andrassy, C., and J. B. Herbich. 1988. Generation of suspended sediment
at the Butterhead. The Dock and Harbour Authority 68~797~:207-216.
d'Angremond, K., A. J. de Jong, C. P. de Waard. 1984. Dredging of pol-
luted sediment in the first petroleum harbor, Rotterdam. Proc. 3rd
U.S.-the Netherlands meeting on Dredging and Related Technology.
Fort Belvoir, Va.: U.S. Army Engineer Water Resources Support
Center.
Hayes, D. F., G. L. Raymond, and T. N. McLelland. 1984. Sediment resus-
pension from dredging activities. Dredging '84. Clearwater, Fla.:
American Society of Civil Engineers.
Hayes, D. F. 1986. Guide to selecting a dredge for minimizing resuspen-
sion of sediment. Environmental Effects of Dredging, Technical
Notes, EEDP-09-1. U.S. Army Engineer Waterways Experiment Station,
Vicksburg, Miss.
Hayes, D. F., T. N. McLelland, and C. L. Truitt. 1988. Demonstration
of innovative and conventional dredging equipment at Calumet Har-
bor, Illinois. MP EL-88-1. U.S. Army Engineer Waterways Experiment
Station, Vicksburg, Miss.
Herbich, J. B. 1975. Coastal and Deep Ocean Dredging. Houston, Tex.:
Gulf Publishing Company.
Herbich, J. B. and S. B. Brahme. 1988. A Literature Review and Techni-
cal Evaluation of Sediment Resuspension During Dredging. TR-88 (in
press). Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment
Station.
McLellan, T. N., R. N. Davis, and D. F. Hayes. 1988. Field studies of
sediment resuspension characteristics of selected dredges. TR
HL-88-(in press). Vicksburg, Miss.: U.S. Army Engineer Waterways
Experiment Station.
Neal, R. W., G. Henry, and S. H. Greene. 1978. Evaluation of the Sub-
merged Discharge of Dredged Material Slurry During Pipeline Dredge
Operations. TR D-78-44. Vicksburg, Miss.: U.S. Army Engineer Water-
ways Experiment Station.
Richardson, T. W., J. E. Hite, R. A. Shafer, and J. D. Ethridge. 1982.
Pumping Performance and Turbidity Generation of Model 600/100
Pneuma Pump. TR HL-82-8. Vicksburg, Miss.: U.S. Army Engineer Water-
ways Experiment Station.
Sato, E. 1984. Bottom sediment dredge CLEAN UP. Principles and results,
management of bottom sediments containing toxic substances. Proc.
8th U.S./Japan Experts Meeting, T. R. Patin, ed. Vicksburg, Miss.:
U.S. Army Engineer Waterways Experiment Station. Pp. 403-418.
Shinsha, H. 1988. Personal Communication. Refresher Dredge, Technical
and Research Institute, Penta-Ocean Construction Company, Ltd.,
Japan.
Yamaguchi, A. 1988. Personal Communication. Kumamoto Prefectural Govern-
ment, Kwmamoto City, Japan.
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