AD-A253 003 DTIC

M_________ 111111I I~ I ELECTE

US Army Corp- JUNI 1 1992

of Engineers

Water Resources

Support Center C

Management of Bottom Sediments

Containing Toxic Substances

Proceedings of the 13th U.S./Japan

Experts Meeting

3-5 November 1987

Baltimore, Maryland

Thomas R. Patin, Editor

I br.!trroNs'TAThMEN'A

Ic pubftc r~em

)istrzbution UntIn•ted

92 6 0 u7o % 92-15193

April 1992
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I April 1992 Final report

4. TITLE AND SUBTITLE S. IFUNDING NUIMBERS

MANAGEMENT OF BOTTOM SEDIMENTS CONTAINING TOXIC

SUBSTANCES: PROCEEDINGS OF THE 13TH U.S./JAPAN

EXPERTS MEETING

6. AUTHOR(S)

Thomas R. Patin, Editor

7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) 8. PERFORMING ORGANIZATION

REPORT NUMBER

9. SPONSORING/ MONITORING AGENCY NAME(S) AND ADORESS(ES) 10. SPONSORING/MONITORING

Water Resources Support Center AGENCY REPORT NUMBER

Fort Belvoir, Virginia 22060;

USAE Waterways Experiment Station, Environmental

Laboratory, 3909 Halls Ferry Road, Vicksburg,

MississivDi 39180-6199

11. SUPPLEMENTARY NOTES

Available from National Technical Information Service, 5285 Port Royal Road,

Springfield, Virginia 22161.

12a. DISTRIBUTION/ AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

13. ABSTRACT (Maximum 200 words)

The 13th U.S./Japan Meeting on Management of Bottom Sediments Containing

Toxic Substances was held 3-5 November 1987 in Baltimore, Maryland. The

meeting is held annually through an agreement with the U.S. Army Corps of

Engineers and the Japan Ministry of Transport to provide a forum for presentation of papers and in-depth discussions on dredging and disposal of contaminated

sediment.

14. SUBJECT TERMS 15. NUMBER OF PAGES

Dredging Sedimentation 398

Marine deposits Toxicology 16. PRICE COOE

17. SECURITY CLASSIFICATION 1B. SECURITY CLASSIFKATION It. SECURITY CASSIFIATO 20. UMITATION OF ABSTRACT

OF REPORT Of THIS PAGE OF ABSTRACT

UNCLASSIFIED UNCLASSIFIED I I

NSN 7540-01-280-5500 Standard Form 29 (Row 2-89)

2 flS-502
PREFACE

The 13th U.S./Japan Experts Meeting on Management of Bottom Sediments

Containing Toxic Substances was held 3-5 November 1987 in Baltimore, Maryland.

The meeting is held annually through an agreement with the U.S. Army Corps of

Engineers and the Japan Ministry of Transport to provide a forum for presentation of papers and in-depth discussions on dredging and disposal of contaminated sediment.

COL Richard G. Rothblum, Commander and Director of the Water Resources

Support Center, was the U.S. Chairman. Mr. Takao Nishimura. Ministry of

Transport, Tokyo, Japan, was the Japanese Chairman.

Coordinator of the organizational activities and editor of this report

was Mr. Thomas R. Patin, current Program Manager, Dredging Operations Technical Support (DOTS) Program, U.S. Army Engineer Waterways Experiment Station,

Vicksburg, Miss. Mr. Charles C. Calhoun, Jr., was Program Manager, DOTS, at

the time of the meeting. Dr. Robert M. Engler is the Program Manager of the

Environmental Effects of Dredging Program, of which the DOTS Program is a

part.

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CONTENTS

PREFACE .............................. ................................ i

ATTENDEES ........................ ............................... .. iv

AGENDA ............................... ................................ vi

TREATMENT OF BOTTOM SEDIMENTS CONTAINING MERCURY AND

MONITORING METHOD USING FISHES by Y. Nakayama,

K. Kyuma, R. Hirota, and M. Fujiki ........... .................. 1

STRATEGIES AND TECHNIQUES FOR HANDLING CONTAMINATED

SEDIMENTS IN THE MARINE ENVIRONMENT by K. Kamlet,

L. Rao, and C. Mooney ................ ........................ .. 23

RESTORATION OF URBAN RIVER WATER QUALITY--INTRODUCTION

OF SECONDARY TREATED DOMESTIC WASTEWATER INTO THE

NOBIDOME CHANNEL by M. Okada, H. Kawahara,

S. Fukushima, and A. Mutoh ............... ..................... .. 48

LONG-TERM MANAGEMENT STRATEGY FOR DREDGED MATERIAL

RELOCATION OR DISPOSAL by N. R. Francingues, Jr ... ........... .. 61

REMOVAL OF NITROGEN AND REFRACTORY ORGANIC COMPOUNDS

IN MUNICIPAL LANDFILL LEACHATE BY SEQUENCING BATCH

REACTOR ACTIVATED SLUDGE PROCESSES by M. Hosomi,

K. Matsusige, Y. Inamori, R. Sudo, M. Okada,

K. Yamada, and Z. Yoshino .............. ...................... .. 69

REGIONAL EFFORTS THROUGH THE IJC TO ADDRESS CONTAMINATED

BOTTOM SEDIMENT PROBLEMS IN THE GREAT LAKES

by A. G. Kizlauskas ................ ......................... .. 87

REMOVAL AND DISPOSAL OF ACCUMULATED ORGANIC SLUDGE

IN THE OSAKA PORT AND HARBOR AREA by M. Konae .... ............ .. 96

IMPACT ASSESSMENT OF IN-PLACE CONTAMINATED SEDIMENTS

ON WATER QUALITY: AN APPROACH by T. L. Hart,

D. Gunnison, and J. Brannon .............. ..................... .. 117

RECENT STUDIES CONCERNING THE CAPPING OF CONTAMINATED

DREDGED MATERIAL by R. W. Morton ........... .................. 126

RELATIONSHIP BETWEEN SEDIMENT POLLUTION AND MACROBENTHIC

COMMUNITIES IN HIROSHIMA BAY by K. Yoshida ..... ............. .. 145

PILOT DREDGING STUDY, NEW BEDFORD HARBOR, MASSACHUSETTS,

SUPERFUND PROJECT by V. L. Andreliunas ....... ............... .. 167

REHABILITATION OF ESTUARIES IN TAKAMATSU HARBOR

by H. Ohira, K. Nikaido, and H. Takagi ....... ............... .. 196

ii
MANAGEMENT OF DREDGED MATERIAL AT TOLEDO, OHIO

by J. R. Adams ..................... ........................... 212

THE BIOFILTER SYSTEM--USE OF AQUATIC PLANTS FOR WATER

PURIFICATION by T. Mishima, T. Inoue, H. Miyoshi,

and H. Chino ..................... ............................ 229

SUMMARY OF THE CE/EPA FIELD VERIFICATION PROGRAM

by R. K. Peddicord ................. ......................... .. 253

RELATIONSHIP BETWEEN THE ENVIRONMENT AND KASAI MARINE PARK

by T. Hiwatashi, T. Tsukagoshi, N. Nakai, Y. Doyama,

S. Wano, and K. Irie ................. ........................ 267

VOLUME CHANGE PREDICTION OF PUMP-DREDGED CLAYEY SOILS

by H. Shinsha, Y. Makimoto, and Y. Watari ...... .............. .. 287

INVESTIGATIONS OF SUBAQUEOUS BORROW PITS AS DISPOSAL

SITES FOR CONTAMINATED DREDGED MATERIAL FROM NEW YORK

HARBOR by J. Tavolaro, M. A. Paula, and R. M. Cerrato .......... .. 308

DISPOSAL AND TREATMENT OF CONTAMINATED DREDGED MATERIAL

by K. Fujii and T. Maekawa ............ ..................... 326

LAKE RESTORATION BY DREDGING by R. F. Gorini ..... ............. .. 355

THE LONDON DUMPING CONVENTION (LDC): REGULATION OF

DREDGED MATERIAL THROUGH GUIDELINES FOR APPLICATION

OF THE ANNEXES TO DREDGED MATERIAL by R. M. Engler .. ......... .. 361

REGIONAL DEMONSTRATION OF BENEFICIAL USES OF DREDGED

MATERIAL IN THE CHESAPEAKE BAY by H. G. Earhart ... ........... .. 378

JAPANESE CLOSING REMARKS, 13TH US/JAPAN EXPERTS MEETING

by T. Nishimura .................. ........................... .. 387

Iiii
ATTENDEES

13TH U.S./JAPAN EXPERTS MEETING ON MANAGEMENT

OF BOTTOM SEDIMENTS CONTAINING

TOXIC SUBSTANCES

Baltimore, Maryland

3-5 November 1987

Japanese Delegation

Mr. Takao Nishimura Director, Environment Division

Co-Chairman Port & Harbor Bureau, Ministry of

Transport

Dr. Motoo Fujiki Professor, Institute of Community

Environmental Medicine, Tsukuba

University

Dr. Mitsumasa Okada Professor, Agriculture and Technology,

Chemical Engineering, Tokyo University

Mr. Masaaki Hosomi Researcher, Freshwater Environmental

Studies Section, National Institute for

Environmental Pollution Research

Mr. Miyoji Konae Port Development Department,

Port and Harbor Bureau, City of Osaka

Mr. Makoto Natori Japan Sediments Management Association

Mr. Tatsuro Kotake Japan Sediments Management Association

Mr. Kazuhiro Yoshida Japan Sediments Management Association

Mr. Kiyoshi Nikaidou Japan Sediments Management Association

Mr. Tohru Mishima Japan Sediments Management Association

Mr. Koichiro Irie Japan Sediments Management Association

Mr. Hiroshi Shinsha Japan Dredging and Reclamation

Engineering Association

Mr. Kunikazu Fujii Japan Dredging and Reclamation

Engineering Association

Mr. Takeo Haekawa Japan Dredging and Reclamation

Engineering Association

iv
Mr. Naoshi Ishimatsu Japan Work Vessel Association

U.S. Delegation

COL Richard Rothblum Commander/Director, Water Resources

Co-Chairman Support Center, US Army Corps of

Engineers

Mr. William Murden US Army Corps of Engineers

Water Resources Support Center

Mr. Thomas R. Patin US Army Corps of Engineers

Waterways Experiment Station

Mr. Frank Hamons Maryland Port Administration

Mr. Glenn Earhart US Army Corps of Engineers, Baltimore

District

Mr. Vyto Andreliunas US Army Corps of Engineers, New England

Division

Mr. John Tavolaro US Army Corps of Engineers, New York

District

Mr. John Adams US Army Corps of Engineers, Buffalo

District

Mr. Kenneth Kamlet URS Corporation, Washington, D.C.

Mr. Richard Gorini Direczor of Planning & Development

Vancouver, Washington

Dr. Thomas Hart US Army Corps of Engineers

Waterways Experiment Station

Mr. Anthony Kizlauskas US Environmental Protection Agency,

Region 5

Dr. Richard Peddicord Battelle Ocean Science, Massachusetts

Mr. Norman Francingues US Army Corps of Engineers

Waterways Experiment Station

Dr. Robert Morton Science Applications International Corp.

Rhode Island

Dr. Robert Engler US Army Corps of Engineers

Waterways Experiment Station

v
AGENDA

13TH U.S./JAPAN EXPERTS MEETING ON MANAGEMENT

OF BOTTOM SEDIMENTS CONTAINING

TOXIC SUBSTANCES

Baltimore, Maryland

3-5 November 1987

Tuesday, November 3. 1987

8:00 - 9:00 Welcome-Deputy District Engineer, Baltimore

District, LTC Joel M. Sauer

Opening remarks-Deputy Division Engineer, North

Atlantic Division, COL Richard G. Riordan

Cochairman - COL Richard Rothblum,

Director, Water Resources

Support Center

Cochairman - Mr. Takao Nishimura,

Director, Environment Division,

Ministry of Transport

9:00 - 930 "Ireatment of Bottom Sediments Containing Mercury

and Watching Method Using Fishes" presented by

Dr. Motoo Fujiki

9:30 - 10:00 "Strategies and Techniques for Handling

Contaminated Sediments in the Marine Environment"

presented by Mr. Kenneth Kamlet

10:00 - 10:30 "Rehabilitation of the Amenity of Urban Rivers--

Introduction of Secondary Treated Domestic

Wastewater Into the Nobidome Channel" presented by

Dr. Mitsumasa Okada

10:30 - 10:45 BREAK

10:45 - 11:15 "The Corps Management Strategy for Highly

Contaminated Bottom Sediments" presented by

Mr. Norman Francingues

11:15 - 11:45 "Sequencing Batch Treatment of Municipal Landfill

Leachate--Removal of Nitrogen and Refractory

Organic Compounds" presented by Mr. Masaaki Hosomi

vi
12:30 - 2:00 Luncheon at OMNI Hotel

Guest speaker-Mr. David Wagner, Port Administrator,

Maryland Port Administration

2:30 - 3:00 "Regional Efforts Through IJC for Managing

Contaminated Bottom Sediments Within the Great

Lakes Area" presented by Mr. Anthony Kizlauskas

3:00 - 3:30 "Removal and Disposal of Accumulated Organic

Sludge in the Port and Harbor Area" presented by

Mr. Miyoji Konae

3:30 - 4:00 "The No-Dredging Option for Highly Contaminated

In-Place Sediments" presented by Dr. Thomas Hart

4:00 - 4:15 BREAK

4:15 - 4:45 "The Synthetic Purification System of Lakes and

Ports" presented by Mr. Tatsuro Kotake

4:45 - 5:15 "Updating the U.S. Experience with Aquatic Capping

of Contaminated Sediments" presented by Dr. Robert

Morton

7:00 - 9:00 U.S. Reception at World Trade Center

Wednesday. November 4. 1987

8:00 - 8:30 "The Consideration of the Relationship Between the

Sediment Pollution and the Benthic Communities in

the Closed Basin" presented by Mr. Kazuhiro

Yoshida

8:30 9:00 "The Planned Pilot Dredging Demontration for the

New Bedford Superfund Project" presented by

Mr. Vyto Andreliunas

9:00 9:30 "Rehabilitation of Estuaries in Takamatsuko

Harbor" presented by Mr. Kiyoshi Nikaido

9:30 - 10:00 "Toledo Harbor as a Case Study of Dredged

Material Management" presented by Mr. John Adams

10:00 - 10:15 BREAK

10:15 - 10:45 "Bio-Filter System--A Water Area Purification

System Utilizing Aquatic Plants" presented by

Mr. Tohru Mishima

vii
10:45 - 11:15 "The Results of the Corps' Field Verification

Program" presented by Dr. Richard Peddicord

11:15 - 11:45 "On the Correlationships of the Natural Environment

and the Park Located Adjacent to the Inner Area of

Tokyo Bay" presented by Mr. Koichiro Irie

11:45 - 12:15 "Hart/Miller Island" presented by

Mr. Frank Hamons

12:15 - 5:00 Field Trip to Hart/Miller Island

6:00 - 8:00 Japan Reception at OMNI Hotel

Thursday, November 5. 1987

8:00 - 8:30 "Volume Change Prediction of Pump Dredged Clay

Soils" presented by Mr. Hiroshi Shinsha

8:30 - 9:00 "Subaqueous Borrow Pit Disposal" presented by

Mr. John Tavolaro

9:00 - 9:30 "Disposition and Treatment of Noxious Sludge"

presented by Mr. Takao Maekawa

9:30 - 10:00 BREAK

10:00 - 10:30 "Lake Restoration by Dredging" presented by

Mr. Richard Gorini

10:30 - 11:00 "London Dumping Convention" presented by

Dr. Robert Engler

11:00 - 11:30 "Recent Beneficial Uses of Dredged Material in

Baltimore" presented by Mr. Glenn Earhart

11:30 - 12:30 Closing Remarks

1:00 - 4:00 Dundalk Marine Terminal Tour (Lunch provided

by MPA)

viii
AD-P0.6 827 U~IhIIilhI Wiii IIIIIIHhID

TREATMENT OF BOTTOM SEDIMENT CONTAINING MERCURY

AND MONITORING METHOD USING FISHES

Y. Nakayama, K. Kyuma

Environment Department, Kumamoto Prefecture

6-18-1 Suizenji, Kumamoto 862, Japan

R. Hirota

Aitsu Marine Biological Station, Kumamoto University

Aitsu, Matsushima, Amakusa, Kumamoto 861-61, Japan

and

M. Fujiki

Department of Environmental Medicine

Institute of Comnunity Medicine, University of Tsukuba

1-1-1 Tennodai, Sakura, Niihari, Ibaraki 305, Japan 0

ABSTRACT 0uih

In Minamata Bay, sediment containing mercury

higher than 25 ppm has accumulated on the bottom, and

dredging work continues. The dredging has been conducted carefully, and secondary pollution as a result

of disturbance of the bottom sediment has been

prevented.

The mercury concentration in fishes was investigated to determine the conditions before dredging. As

a result, a good correlation between the mercury concentration in fishes and the body length was found.

Six kinds of fishes were chosen for monitoring. These

were selected because they were present in sufficient

numbers, the mercury concentration in them was adequate, and there was good correlation between mercury

concentration and body length.

The monitoring work has been successful, based on

the results obtained.

INTRODUCTION

Minamata Bay is located near the southern tip of Kumamoto Prefecture.

The Port of Minamata, which is on Yatsushiro Sea, is an important port. A

chemical factory on Minamata Bay used mercury as a catalyst in making

acetaldehyde and vinyl chloride for 40 years, from 1932 to March 1971. It has

been estimated that 70 to 150 tons, or more, of mercury was discharged to the
bay. As a result, most of the bay demonstrated mercury concentrations higher

than 25 ppm. The thickness of polluted sediment reached 4 m at some points of

the inner part of thickness of the bay.

Some of the mercury used as the catalyst was changed into methyl mercury

by a secondary reaction in the acetaldehyde reaction plant. Methyl mercury in

wastewater from the plant was discharged to the bay, and from the seawater,

accumulated into fish tissue. Many inhabitants who ate the polluted fishes

were poisoned. The total mercury concentration in fishes has been investigated for many years and was found to be approximately 20 ppm in 1960. Since

the factory has discontinued the use of mercury, the total mercury concentration in fish has decreased to 1 ppm or less. The mercury concentration in

fish from the bay, however, is higher than that of fish from other districts.

Furthermore, the total mercury concentration found in some fish from the bay

is higher than 0.4 ppm (the safety guideline for fishes).

In Japan, the required level for removal is 25 ppm. So, the government

of Kumamoto Prefecture decided to remove the sediment with a mercury concentration higher than 25 ppm. This work was begun in October 1977. The inner

part of the bay (582,000 m2 , 726,000 m3 ), which had a thick bottom layer of

sediment with a high concentration of mercury, was chosen as the disposal area

for the dredged sediment. Sediments in the other parts of the bay

(1,510,000 m 2 , 784,000 m3 ) have been dredged and pumped directly to the disposal area. Dredging has continued to the present (Figure 1).

A cutterless pump has been used, and the work has been conducted carefully to prevent secondary pollution from disturbance of the bottom sediment.

Also, the water quality and marine products have been monitored to detect any

further deterioration caused by the work in the bay. When further pollution

is found, the dredging work is suspended by the government of Kumamoto Prefecture until the origin of the pollution is traced; then, the dredging work is

resumed after removal of the origin.

The water quality monitoring was described in detail by Nakayama et al.

at the 12th US/Japan Experts Meeting on Management of Bottom Sediments Containing Toxic Substances, November 1986, Yokohama, Japan. In this paper, the

authors will report on the monitoring method using fishes.

TREATMENT OF SEDIMENT

Defense nets and sounders to detect fishes moving into or out of the bay

were set along the border of the dredging area. As a result, fishes containing mercury were kept within the bay.

A temporary separation revetment (length, 430 m) was constructed between

Koiji Island and Myojin Cape to prevent the diffusion of pollutants by decreased current in the bay working area.

The cutterless pump was used for dredging in the bay because it did not

stir the bottom sediment. The bottom sediment containing mercury was pumped

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directly to the disposal area. After primary sedimentation in the disposal

area, the effluent was pumped into the treatment plant and treated with a

coagulant. The effluent from the plant was discharged into the bay.

Dredging in the first area was done from 1980 to 1985. This was an experimental area, and new harbor facilities will be constructed to replace

those existing. During dredging in the first area, no further pollution was

confirmed. Therefore, the same dredging method has been applied to the second

(main dredging) area.

In the second dredging area, sand-compaction work, construction of a

bulkhead, and construction of the effluent treatment plant have been completed, and dredging continues. When dredging is finished, the seawater in

the disposal area will be drained. The sediment in the disposal area will be

covered with sand or soil from the mountains. The work in Minamata Bay is

scheduled for completion by March 1990.

MONITORING METHOD USING FISHES

It is well known that the ratio of accumulation of mercury into fishes is

significant. It is said that the ratio of accumulation of total mercury from

water into fishes is a thousand times. It has also been reported that the

ratio of accumulation of methyl mercury from water into fishes is ten thousand

to a million times. Moreover, mercury intake from water to fishes is quick.

Therefore, fishes in water containing mercury as an undetectable concentration

take up mercury for the short term; as a result, mercury in fishes increases

to a detectable concentration. Based on these facts, a monitoring program

using fishes (Table 1, Figure 2) was designed and implemented.

Confinement of Fishes Within the Bay

The defense net was set along the dredging area borderline to keep fishes

containing mercury within the bay. The defense net could not be set on a part

of the waterway; thus, sounders were set on that part of the waterway.

Five collection nets have been set in the dredging area, and fishes have

been caught in the bay. These were incinerated.

Mercury Concentrations in Fishes

Outside Dredging Area

To confirm the mercury concentration in fishes from outside the dredging

area, an investigation of 10 principal fish species has been carried out four

times a year. The appraisal was based on the safety guidelines for fishes

(total mercury concentration, 0.4 ppm).

Within Dredging Area

It is thought that the mercury concentration in fishes depends upon the

mercury concentration in water, the feeding habit of fishes, the physiological

properties of fishes, the seasonal condition, the body length, and the ecological characteristics of fishes. The mercury concentration in fishes from the

dredging area was investigated to determine their conditions before dredging.

4
TABLE 1. MONITORING PROGRAM (FISHES AND PLANKTON)

Monitoring Area Contents

Defense for moving Defense net Nets were set along the dredging area

fish borderline.

Collection net Five collection nets were set in the

dredging area; fishes caught were

disposed.

Monitoring of fish Outside of 11 kinds of fishes

dredging area T-mercury: 4 times/year

Dredging area Mebaru, marble rock fish, perch,

gilthead, sasanohabera, ishimochi

T-mercury: I time/month

Monitoring of Outside of Zooplankton

plankton dredging area T-mercury: 6 times/year

Dredging area Zooplankton

T-mercury: 6 times/year

Fish-rearing test Dredging area Red sea bream, mejina

T-mercury: 3 times/month

From the above results, fishes were grouped into three classes based on mercury concentration. In the first class, the mercury concentration was constantly over 0.4 ppm as total mercury; the second class fluctuated about the

0.4-ppm level, and the third class was constantly lower than 0.4 ppm. It

became clear that there was a good correlation between the mercury concentration in fishes and body length (Table 2, Figures 3-8).

Six kinds of fishes were chosen for monitoring based on the criteria of

being sufficient in number, having an adequate mercury concentration to discriminate the variation, and good correlation between mercury concentration

and body length. The fishes selected were: mebaru, marble rock fish, perch,

gilthead, sasanohabera, and ishimochi. The mercury concentration in these

fishes was investigated once a month.

Fish Rearing Test

To determine as quickly as possible the effect of mercury bloaccumulation

into the fish as a result of dredging, red sea bream and mejina obtained from

an unpolluted area were reared in fish-rearing cages in the dredging area.

The total mercury concentration in these was measured every 10 days.

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Mercury Concentration in Plankton

Zooplankton were collected within and outside the dredging area, and

total mercury concentration was measured every 2 months.

MONITORING RESULTS

Fishes Outside the Dredging Area

Ten fish species were investigated four times a year. The mercury concentration in all fishes has been lower than 0.4 ppm (safety guideline for

fishes).

Fishes Within the Dredging Area

To minimize the deviation in mercury concentration in fishes caused by

the body length, the value of the mercury concentration was corrected as follows. From the mercury concentrations and body lengths obtained in investigations of fishes of the same species for the past 3 years, a linear regression

was calculated by the method of the least squares. A mean of the body length

was also calculated, and it was used as a standard body length. The value of

the mercury concentration and the body length of fishes were plotted, and a

line was drawn parallel to the linear regression line and through the plotted

point. Then, a corrected value of the mercury concentration was obtained from

an intersection of the drawn line and the standard body length line. In practice, the corrected value of the mercury concentration was obtained by the

calculation using the linear regression formula of each fish species.

Six principal fishes have been investigated one time a month, and it was

confirmed that the transition of the mercury concentration in these fishes has

been normal (Figures 9-14). These results indicate no effects from the

dredging.

Fish Rearing Test

The 6-month fish rearing test has been conducted repeatedly. The transition of the mercury concentration in red sea bream and mejina was similar to

the results of the past rearing test (Figure 15). From these results, no

effects of the dredging have been found.

Plankton Investigation

The transition of the mercury concentration in the zooplankton within and

outside the dredging area has been normal, and no effects of the dredging have

been found.

DISCUSSION

From the investigation of the mercury concentration in fishes over the

past several years, a good correlation between the mercury concentration and

body length of fishes was found in all kinds of fish. In the monitoring of

fishes, the results obtained from the larger fishes must not be compared

directly with the results from the smaller fishes to determine the transition

of the mercury concentration in fishes. Therefore, the value of the mercury

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concentration in fishes was corrected by the calculation using the linear

regression formula of each fish species. This minimized the deviation of mercury concentration among fishes and allowed comparison of the mercury concentration in the larger fishes and smaller fishes.

The mercury concentration in six kinds of fishes from the dredging area

showed an upward trend until 1981. Afterward, the mercury concentration decreased until 1984. The mercury concentration in each of the fishes except

mebaru demonstrated a transitional increase in 1984. Since 1985, the mercury

concentration in each of the fishes has shown a downward trend or equilibrium.

From these results, the mercury concentration in six kinds of fishes has indicated a tendency of decrease (with upward and downward variation) since the

use of mercury was discontinued in the factory.

CONCLUSIONS

In dredging of bottom sediments containing mercury, it is very important

that the work is carried out carefully and that water quality is not allowed

to deteriorate, including the prevention of secondary pollution from stirring

the bottom sediment. Moreover, it is important to detect any secondary pollution and to monitor successive work to prevent deterioration.

For the dredging work in Minamata Bay, four water quality monitoring

methods were used:

a. Measurement of turbidity (as discussed by Nakayama et al.,

12th US/Japan Experts Meeting), which obtained rapid results.

b. Corrected value of mercury concentration in fishes to determine

accurately the transition of mercury.

c. Fish rearing test, using red sea bream and mejina.

d. Measurement of mercury concentrations in plankton to determine the

effect of mercury bioaccumulation.

From the results of the monitoring work, no further deterioration of the

water quality and no further pollution of fishes have been found since initiation'of the dredging. From the facts described above, it was concluded that

method of monitoring fishes as the indicator of the pollution accurately

detected the effects induced by the dredging work and led us to obtain successful results.

22
A -O 82'8--_ '

STRATEGIES AND TECHNIQUES FOR HANDLING CONTAMINATED

SEDIMENTS IN THE MARINE ENVIRONMENT

K. S. Kamlet, L. Rao, and C. Mooney

A. T. Kearney, Inc.

699 Prince Street, PO Box 1405

Alexandria, Virginia 22313

ABSTRACT

Bottom sediment contamination in the marine

environment has its origins in point and nonpoint

source pollution, direct dumping, onshore hazardous

waste disposal, and in-water and onshore spills. It

is significant because of its potential to adversely

affect aquatic resources, contaminate the human food

chain, degrade water quality, constrain navigational

dredging, and complicate hazardous waste site remedial

action. The US Environmental Protection Agency's

(USEPA) Superfund National Priorities List and the

National Oceanic and Atmospheric Administration's

(NOAA) Coastal Hazardous Waste Site Review were examined to identify coastal Superfund sites in which

bottom sediment contamination appeared to be a significant factor. Of the latter sites, information was

reviewed for those that had progressed to at least the

Feasibility Study stage and, consequently, had recommended remedial actions. Various combinations of

excavation, stabilization, capping, monitoring, and

cleanup of onshore contamination, as well as no action, constituted the preferred strategies in

10 sample cases evaluated. Although differing approaches may well be warranted in the widely different

fact patterns involved, each cleanup plan appeared to

have been developed on a totally ad hoc basis, completely independent of similar Superfund cleanups, or

other relevant experience, in other settings. The

Marine Board of the National Academy of Sciences/

National Academy of Engineering has constituted a Committee on Contaminated Sediments to provide an improved understanding of contaminated marine sediments,

to serve as a basis for management decisions and technical research and development. The approach of this

committee effort, aimed at suggesting improved remedial technologies and strategies, is discussed.

2311111 292-16001
INTRODUCTION

Bottom sediment contamination comes from a variety of sources (Figure 1):

a. Runoff from construction and farming activities, and atmospheric

fallout (nonpoint source pollution).

b. Discharges from industrial and municipal sources (point-source

pollution).

c. Direct dumping (both from shore, by tractor and truck, and at sea via

ocean dumping).

d. Onshore waste disposal activities (e.g., coastal hazardous waste

landfills).

e. Accidental spills from shore-based and waterborne sources.

i m AIR NONPOINT

POLLUrTION SOURCES

SPOINT.

CONSTRUCTION SOURCE

DISCHARGES

FARMING

WASTE DISPOSAL IL

S• DIRECT DUMPING

Figure 1. Schematic representation of sources of bottom

sediment contamination

24
US LEGAL FRAMEWORK

These contamination sources fall within the regulatory jurisdiction of

several Federal environmental statutes (Figure 2):

a. The Clean Water Act, as most recently amended by the Water Quality

Act of 1987 (covers point and nonpoint source pollution and spills of

oil and hazardous substances).

b. The Superfund Law (technically referred to as the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as

amended by the Superfund Amendments and Reauthorization Act of 1986)

(covers inactive and abandoned hazardous waste sites, areas where

hazardous substances have come to be located, releases of environmentally threatening pollutants or contaminants, and injuries to

natural resources resulting from such releases).

(CLEAN WATER ACT)

AIR NONPOINT

POLLUTION SOURCES

(CLEAN WAT R ACT)

S::i~ii:•ii•!•.• POINTCONSTRUCTON SOURCE INDISCHARGES

(CLEAN WASTE DISPOSAL PT

WATER

AC.A.

FUND)

Figure 2. US laws that regulate the sources of bottom

sediment contamination

25
c. The Resource Conservation and Recovery Act, as amended by the Hazardous and Solid Waste Amendments of 1984 (covers the generation, transport, handling, and disposal of hazardous waste at active hazardous

waste management facilities).

d. The Marine Protection, Research, and Sanctuaries Act (better known as

the Ocean Dumping Law) (covers the transportation of materials from a

US port for the purpose of dumping them in ocean waters, and the

associated ocean dumping).

The US Regulatory Framework is summarized in greater detail in Table 1.

Special note should be taken of the Superfund Law, most recently amended

in 1986. Although it is often regarded as covering only inactive or abandoned

hazardous waste sites, it is, in fact, very broad in Its coverage. It

encompasses:

a. Any area where a hazardous substance has come to be located--whether

by intentional dumping or by accidental spillage.

b. Releases or threatened releases into the environment of any hazardous

substance or any environmentally threatening pollutant or

contaminant.

c. Any injury to, destructioa of, or loss of natural resources--defined

very broadly--resulting from such pollutant releases.

The applicability of Superfund has been limited in practice by the USEPA,

primarily by means of a Hazard Ranking System (HRS) that is used to place

Superfund sites on a National Priorities List (NPL). Only NPL sites come

within the scope of Superfund's full-scale remedial cleanup program.

The HRS methodology employed by the USEPA to date to give sites a hazard

ranking places very heavy weight on the potential for contamination of drinking water sources and resultant health impacts and gives little, if any,

weight to the possible contamination of edible fish and shellfish. In other

words, the USEPA has emphasized the drinking water pathway of human exposure

to the virtual exclusion of the food chain pathway.

Contaminated bottom sediments do not often threaten drinking water supplies--especially in the marine environment. It is, therefore, not surprising

that there are few sites on the NPL involving predominantly bottom sediment

contamination. This may have to change, however, since the 1986 Superfund

amendments directed USEPA to revise the HRS to require consideration of the

potential for contamination of "natural resources in the human foodchain."

SIGNIFICANCE OF BOTTOM SEDIMENT CONTAMINATION

Bottom sediment contamination can be of great environmental significance

from the following standpoints (Figure 3):

a. It can damage aquatic resources in terms of lethal and sublethal

effects, including reproductive impairments and tumor and disease

induction.

26
TABLE 1. US REGULATORY FRAMEWORK

Law Scope of Coverage

"Superfund" (CERCLA/SARA) Any area where a hazardous substance has come

to be located

Removal or remediation of any release or

threatened release into the environment of

any hazardous substance (or of any pollutant

or contaminant that may present an imminent

and substantial danger to the public health

or welfare)

Hazard Ranking System and National Priorities

List to determine priorities for remedial

action (and, to the extent practicable,

removal action)

Responsible parties liable for damages for injury to, destruction of, or loss of natural

resources

Liability for releases associated with the application of registered pesticides is

excluded

Liability for "federally permitted releases" is

limited to that provided elsewhere (if any)

Clean Water Act

Dredge and Fill Program Dredging of navigable waters is covered by Sec-

(Section 404) tion 10 of the Rivers and Harbors Act

Covers the discharge of dredged or fill material into the navigable waters at specified

disposal sites

Oil and Hazardous Discharges of oil and hazardous materials into

Substance Spills the navigable waters of the United States,

(Section 311) adjoining shorelines, the contiguous zone,

certain OCS and deepwater port activities, or

which may affect natural resources under exclusive US management authority

Excludes discharges in compliance with a Clean

Water Act permit or identified in a permit or

permit application

Authorizes removal whenever there is a covered

discharge or substantial threat of discharge

Provides for abatement of any imminent and substantial threat to the public health or welfare because of an actual or threatened

release

(Continued)

27
TABLE I (Concluded)

Law Scope of Coverage

Clean Water Act (Cont.)

In-Place Toxic Pollutants In-place pollutants, with emphasis on toxic

(Section 115) pollutants in harbors and navigable waterways

Removal and appropriate disposal, in coordination with the US Army Corps of Engineers,

from critical port and harbor areas

Great Lakes Program Removal of toxic pollutants from Great Lakes

(Section 118(c)(3)) sediments

Toxic "Hot Spots" Control strategies to reduce toxic pollutant

(Section 304(1)) inputs into contaminated waterway segments

National Estuary Program Identification and protection of nationally

(Section 320) significant estuaries

Nonpoint Sources Best management practices and measures to re-

(Section 319) duce pollution from nonpoint sources and

improve water quality of navigable waters

Marine Protection, Re- Transportation for the purpose of dumping, and

search, and Sanctuaries dumping in ocean waters

Act (Ocean Dumping) Prohibited without a permit and except in

accordance with ocean dumping criteria

Resource Conservation and

Recovery Act

Hazardous Wastes Listed or characteristic wastes (or mixtures

(Subtitle C) or derivatives thereof), including those displaying toxic properties when subjected to

prescribed extraction and leaching procedures

Subject to manifesting requirements; disposal

limited to interim status or permitted

hazardous waste facilities. Facilities subject to permitting, monitoring, and postclosure care requirements

Solid Wastes Prohibition against "open dumps"; encouragement

(Subtitle D) of resource recovery and "sanitary landfills"

State (and local) lead, subject to Federally

approved criteria that must protect human

health and the environment

28
Impacts on aquatic resources

Threats to human foodchain

Figure 3. Significance of bottom Degrades waterqualty

sediment contamination

Constrains navigational dredging

Complicates site clean-up

b. It can harm the health of human seafood-eaters (via benthic bioaccumulation and trophic transfer).

c. It can degrade water quality (by acting as a reservoir of ongoing

contamination of the overlying water column).

d. It can constrain navigational dredging (by limiting options for the

disposal and management of the resulting dredged material, and

thereby the ability to dredge in the first place).

e. It can complicate the cleanup of hazardous waste sites because of the

difficulty of working under water and the greater risk in an aquatic

setting of stirring things up and creating new problems.

NEW CLEAN WATER LEGISLATION

It is worth noting several provisions of the Water Quality Act of 1987.

This amendment of the Clean Water Act established or gave new momentum to

several relevant and important programs:

29
a. A program geared to removing toxic pollutants from Great Lakes

sediments.

b. A program designed to reduce toxic pollutant inputs into contaminated

waterway segments.

c. A program to identify and protect nationally significant estuaries.

d. A program to reduce pollution from nonpoint sources.

Since remedial cleanups of sites with contaminated sediments can have

lasting effectiveness only to the extent that the ultimate land-based sources

of the original contamination are curtailed, the existence of regulatory

mechanisms (and funding sources) to deal with these sources is essential. The

Water Quality Act of 1987 provides important additions to the preexisting

framework of such mechanisms.

REVIEW OF COASTAL SUPERFUND SITES

The following tables (Tables 2-6) of (predominantly) coastal Superfund

sites with an apparent sediment contamination problem were compiled using the

following sources of information: USEPA computer printouts (from the computerIzed CERCLIS inventory of Superfund sites) of final NPL sites in coastal

states; USEPA site descriptions of final and proposed NPL sites (through about

Update 3); NOAA Coastal Hazardous Waste Site Review: Site Reports for 1984,

1985, and 1987 (covering proposed NPL sites through Update 6); Superfund

Records of Decision (RODs) available through USEPA Headquarters; and telephone

interviews with USEPA Regional Superfund Coordinators.

This review should not be treated as definitive or exhaustive. There

were numerous gaps in the information readily available to us. (In some

cases, we may have included in our tables sites that are located far from any

coastline or where no accumulations of contaminants on bottom sediments have

been noted.) This effort was intended to be no more than what it is--an

attempt to approximate the size of the universe of Superfund NPL sites with

known or potential sediment contamination problems. We also hoped to get a

feel for the number and identify of those sites for which specific remedial

actions have been proposed, and an indication of the combinations of remedial

options selected in each case.

Table 2 catalogs the coastal Superfund sites reviewed by NOAA (and regarded by NOAA as posing a high hazard potential to coastal natural resources)

for which RODs were available at USEPA Headquarters. RODs almost invariably

specify the remedial technology or technologies chosen by USEPA to be employed

in the site cleanup. Not uncommonly, however, site cleanup work may be divided into phases, or may deal with different operable units or areas of the

site separately. In such cases, separate RODs may be prepared for each separate element or phase. Of the 14 sites listed in Table 2, only three clearly

meet the criteria of being (a) definitely coastal, (b) clearly involving contaminated sediments, and (c) clearly having had remedial technologies considered for their contaminated sediments. These site names are underlined in the

far left column of the table.

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Table 3 lists similar sites on NOAA's high-hazard list for which RODs

were not readily available from USEPA Headquarters, but for which we were able

to obtain information on selected remedies through telephone interviews with

USEPA Regionai Superfund Coordinators. Of the 11 sites listed in this table,

four appeared to meet the criteria applied in Table 2. These site names are,

again, underlined.

Table 4 lists 19 sites that, although viewed by NOAA as posing a significant potential hazard to coastal natural resources, scored less than the 28.5

cutoff (under USEPA's Hazard Ranking System) required to list the site on the

NPL. As unlisted sites, these sites are not eligible for full-fledged cleanup

under Superfund. (Only more limited emergency removals are possible, where an

imminent hazard is believed to exist.) Only two of these sites (site names

underlined) appear to clearly implicate bottom sediment contamination.

Table 5 lists nine NPL sites on NOAA's high-hazard list (and one site

inexplicably not on NOAA's list) for which Remedial Investigations and Feasibility Studies (RI/FS) have been completed under Superfund. Although a final

ROD does not yet exist for these sites, the available RI/FS report contains

expert recommendations on the preferred remedial technology or technologies

for site cleanup. Three of these sites (site names underlined) seem to

clearly involve bottom sediment contamination and apparently have explored

specific remedial technologies for addressing this contamination.

Table 6 lists NPL sites with potential bottom sediment contamination and

an apparent coastal location (whether or not on the NOAA high-hazard list)

which have not yet reached the RI/FS stage. Consequently, no preferred remedial technology has yet been recommended for any of these sites. Of the 25

sites on this list, four seem clearly to involve bottom sediment problems in a

coastal marine setting (site names underlined).

Comparison of the 17 sites whose names were underlined in Tables 2-6

(i.e., coastal marine Superfund sites that clearly involve contaminated bottom

sediments) shows that site locations ranged from Maine to Louisiana to

Washington State and that the sites' HRS scores ranged from 25.53 to as high

as 58.3.

It may be observed that this list of 17 sites is not very long--

especially when one considers that there are now more than 1,500 sites

(present or proposed) on USEPA's Superfund National Priorities List. However,

this list is also clearly not complete.

Figure 4 summarizes, for 10 of these sites (those for which remediation

of contaminated sediments had been considered and on which we had information)

the elements of a remedial strategy employed (or proposed to be employed) at

each site. The elements considered include: excavation, onsite or off-site

stabilization (including fixation and thickening), capping, monitoring,

cleanup of onshore contamination as a means of curbing a sediment contamination source, and no action.

Although it can be seen that excavation or dredging was a frequently

adopted approach, appearing in at least half the sites in this figure, there

was wide variation from site to site in the combination of techniques

44
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proposed. Even where excavation was selected as the primary technology, in

three of five cases it was to be used together with other techniques (which

differed in all three cases).

One evident conclusion from this table is that there is little consistency in the approach taken from one site to the next. This in itself is not

an indictment. Different contaminants and widely differing site conditions

make it entirely appropriate that different strategies and mixes of technologies be employed from one situation to another. The more serious criticism

(which, at this stage, is no more than a strong impression) is that a systematic thought process is not followed in deciding whether to excavate or treat

contaminated sediments, on the one hand, or to leave them entirely alone, on

the other.

It was precisely for this reason that the National Academy of Sciences/

National Academy of Engineering Marine Board (under the National Research

Council and the Commission on Engineering and Technical Systems) has initiated

the study that is outlined below.

MARINE BOARD STUDY

The Marine Board has formed a nine-member Contaminated Sediments Committee to conduct an assessment aimed at providing an improved understanding of

contaminated marine sediments. This assessment is intended to aid managers

and decisionmakers in developing a more cohesive and systematic framework for

making remedial action decisions involving contaminated sediments. It will

also, hopefully, help to define technical research and development needs and

priorities.

To accomplish these objectives, the Committee will be holding a workshop

(probably in the late winter of 1987-88). This workshop will:

a. Examine the extent of bottom sediment contamination in coastal areas

of the United States and its significance.

b. Review the state of practice of technology for cleanup and

remediation.

c. Identify and appraise alternative management strategies.

d. Identify research and development needs and issues for subsequent

assessment (both by the Marine Board and by others). These issues

may well include sediment classification and waterway management

strategies.

The Committee will then prepare a report which includes:

a. Proceedings of the workshop.

b. A summary appraisal describing relevant technical and programmatic

issues.

c. Recommendations to the US Army Corps of Engineers, the USEPA, and

others for further study and technical development.

46
CONCLUSIONS

Much remains to be learned about optimal strategies for cleaning up inactive hazardous waste sites. This is especially the case where the contamination that must be cleaned up is underwater. The very attempt to remove contaminated bottom sediments could result in the resuspension and mobilization

of contaminants (with resultant impacts on aquatic resources, including food

chain species), such that the "cure" could easily turn out to be worse than

the "disease." Clearly, such decisions must be made with great care and

justifiably may differ from location to location.

On the other hand, the fact that sites such as the James River Kepone

site and the Hudson River PCB site could entail diametrically contrasting

remedial action decisions (leave the sediment alone, to be covered over by

natural deposition, in the Kepone case; excavate contamination hotspots, in

the PCB case) raises understandable questions about the thought process used

in making such a decision. This is especially so for sites like these two,

which appear to be so similar: both involved bottom sediment contamination

with a bioaccumulative organohalogen, and are located within a few hundred

miles of one another.

It is hoped that the Marine Board's study will provide new insights into

the nature and extent of bottom sediment contamination in coastal environments. Hopefully, too, the results of this study will aid decisionmakers in

deciding when the best course of action is active remediation, as opposed to

benign neglect.

47
RESTORATION OF URBAN RIVER WATER QUALITY--

INTRODUCTION OF SECONDARY TREATED

DOMESTIC WASTEWATER INTO THE

NOBIDOME CHANNEL

M. Okada

Department of Chemical Engineering

Tokyo University of Agriculture and Technology

2-24-16 Nakamachi, Koganei, Tokyo 184, Japan

H. Kawahara

Institute of Environmental Science

Tokyo Metropolitan Government, 1-7-5 Shinsuna

Koutou-ku, Tokyo 136, Japan

___ S. Fukushima

Yokohama City Institute for Environmental Research ___ 1-2-15 Takigashira, Isogo-ku, Yokohama 235, Japan

A. Mutoh

Japan Environmental Health Center, 10-6 Yotsuya-Kamimachi

Kawasaki-ku, Kawasaki 210, Japan

ABSTRACT

Comprehensive surveys for water quality and benthic invertebrates were carried out in the Nobidome

Channel in which filtered secondary wastewater was introduced to restore the waterfront. The suspended

solids concentration increased downstream as a result

of erosion of the bank and the bottom. Selfpurification was not significant for biological oxygen

demand (BOD). The dominant species of periphyton and

benthic invertebrates were typical of polluted streams

and coincide with the poor water quality. Standing

crops, however, were less than expected based on nutrient concentrations, with the major controlling factors being the lighting conditions affected by the

fall of leaves from the deciduous broad-leaved trees

around the channel and the stability of sediments.

Distribution of Chironomidae was strictly controlled

by the repeated dosage of growth-inhibition chemicals.

INTRODUCTION

Sewage works and sediment dredging improved the water quality of polluted

rivers running through or near large cities. However, all the wastewater and

stormwater that used to flow into the rivers is collected into sewer pipes and

transferred directly to a wastewater treatment plant generally located

48
downstream of the river basin. Thus, in spite of the improved quality of

water, the quantity of running water has decreased and, in some small streams,

no running water can be observed except for stormwater runoff after construction of the sewer system. There are many small streams in the vicinity of

Tokyo in which the rate of flow has decreased remarkably in recent years.

Rivers or streams are important to the quality of life in urban areas and

attract many people to the waterfront. Therefore, the decrease or disappearance of flow is a serious problem, and in some cases, may be more serious than

water pollution. There is now an urgent need to maintain the river environment

not only for water quality but also for quantity of running water (Ooe 1986).

Many municipalities are now planning or have begun to introduce clean

water to keep the necessary amount of running water for restoration or improvement of the waterfront (Japan Environment Agency 1984). However, many

large cities are now facing a shortage of water for this purpose. They are

now looking at treated wastewater as one of the most promising sources of

water for maintaining riverflow.

The first full-scale project was the restoration of a clear stream in the

Nobidome Channel in Tokyo (Tokyo Metropolitan Government 1984). Secondary

wastewater treated by the activated sludge process and rapid sand filtration

has been introduced into the channel where no natural water was running, i.e.,

running water is kept only by the secondary effluent. It has been pointed

out, however, that secondary effluent from the activated sludge process has a

high potential to stimulate algal growth in shallow rivers and to deteriorate

water quality (Ohtake, Aiba, and Sudo 1978).

The purpose of this study was to evaluate the use of secondary effluent

for maintaining riverflow under a full-scale project for the first time in

Japan. Water chemistry and benthic invertebrates were surveyed for 2.5 years

following introduction of the effluent.

THE NOBIDOME CHANNEL PROJECT

A map of the Nobidome Channel is shown as Figure 1. It was constructed

in the 17th century by orders of Nobutsuna Izunokami Matsudaira, governor of

the Nobidome area and civil engineer for the construction of Tamagawa Jousui

to provide a tap water supply to downtown Edo (Tokyo) and to develop new agricultural fields in the Musashino Plateau, the western part of Tokyo. Water in

the Tamagawa River was diverted into the channel and distributed over the plateau for irrigation. It is recorded that agricultural production in the plateau increased up to 10 times as a result. In addition to the irrigation, the

channel was used for drinking water and for hydrant and miscellaneous usage

until recently (Tokyo Metropolitan Government 1984).

With the spread of metropolitan Tokyo during the rapid economic growth

after World War II, the channel area was developed for housing, without construction of a public sewer system. The channel became a waterway for the

discharge of polluted water and sewage from septic tanks, and the demand for

irrigation decreased. In 1973, the Tokyo Metropolitan Government stopped the

diversion from the Tamagawa River to cope with the shortage of water to downtown Tokyo. Construction of a sewer system resulted in diversion of the

wastewater flow from the channel.

49
TOKYO St.

f r TmAGAVA R.

I

Figure 1. Aerial map of the Nobidome Channel and sampling stations

In 1974 the government of Tokyo prepared a plan to restore the former

waterfront of the Nobidome Channel as one of the projects to create a better

urban environment in Tokyo. Secondary effluent from Tamagawa Jouryu Wastewater Treatment Plant was filtered through a continuous upflow, moving sandbed

filter and transferred through a pipeline for 8.7 km to the channel. The

objectives were to obtain water with an average BOD of 8 mg/i, at a flow rate of 20,000 cu n/day. The construction began in 1981, and the discharge of

secondary effluent started in August 1984.

FIELD SURVEYS AND CHEMICAL/BIOLOGICAL ANAYSES

Sampling of water and benthic invertebrates was carried out at five sampling stations (St. 14, 13, 11, 10, and 8) distributed between the point of

discharge (St. 14) and the points where the channel crosses the border between

the Toyo Metropolitan District and Saitama Prefecture (St. 8). The distance

between St. 14 and St. 8 is 8,700 m. All of the areas channel surveyed were

open channel except for a short closed channel near St. 13.

Hydraulic and chemical parameters of running water, periphyton, and benthic invertebrates of the bottom sediment were analyzed 13 times during the

2.5 years following discharge. All samples were taken in the morning. The

hydraulic parameters were width and depth of the channel and flow rate. Water

50
temperature and light intensity at the water surface were also monitored. The

chemical parameters determined were pH, suspended solids (SS), BOD, chemical

oxygen demand/manganese (CODMn), total organic carbon (TOC), dissolved organic

carbon (DOC), and various forms of nitrogen and phosphorus. The numbers of

coliform groups and fecal colis were also determined. All determinations were

conducted according to the Methods for Chemical Analysis of Water and Wastes

(USEPA 1976).

Periphyton were collected from a 5- by 5-cm quadrat on the surface of a

relatively flat stone on the bottom or from the surface of bottom sediments,

using a nylon toothbrush. Benthic invertebrates were collected from a 30- by

30-cm quadrat by using a D frame net with a mesh of GG40. Species were identified by microscopic examination.

RESULTS AND DISCUSSION

Hydraulic Parameters

In other small streams in the Tokyo area, the banks and bottom were covered with concrete before discharge; however, no protection was executed in

this channel. The surface of the banks and bottom was clay, as before

(Table 1). The maximum rate of flow observed at the center of the channel

ranged from 40 to 70 cm, except for St. 13 where the bottom has the largest

slope and the rate was more than 100 cm. Gravels have been exposed at this

station by erosion.

TABLE 1. CHARACTERISTICS OF NOBIDOME CIIANNEL (JUNE 22, 1985,

FLOW RATE = 20,000 cu m/day)

Station

Parameter 14 13 11 10 8

Width, m 1.6 1.6 1.8 1.6 1.6

Maximum depth, cm 20 20 26 25 25

Maximum flow rate, 43 105 55 64 55

cm/sec

Bottom material Clay Gravel + clay Clay Clay Clay

Time of flow between 51 42 52 40

stations, min

The width ranged from 1.6 to 1.8 m, and maximum depth was between 20 and

26 cm. Although the values shown in Table 1 were determined at the specified

date, little difference in values was noted throughout the sampling period because the amount of discharge is controlled at a constant level at the pumping

station.

51
The intensities of light at the surface of the channel compared with open

(unshaded) areas nearby are shown in Table 2. Large relative intensities

were noted at St. 8, where only a small number of trees cover the channel. In

the other stations, many deciduous broad-leaved trees, such as zelkova, grow

on the banks and cover the channel. In summer, when their leaves shade direct

sunlight from the surface of the water, small values of relative intensity

were recorded. After leaf fall in autumn, high values of relative intensity

were noted.

TABLE 2. RELATIVE INTENSITY OF LIGHT (PERCENT)

AT THE SURFACE OF THE CHANNEL

Station

Date 14 13 11 10 8

Nov 1985 2-90 5-50 1-5 8 100

Feb 1986 100 90 100 80 70

Apr 1986 42-67 61-69 20-33 43-58 92

May 1986 7-10 9-11 1-5 1-4 93

Jun 1986 3-4 6 1-2 2-4 74

Jul 1986 1-3 4-5 1-2 2-3 81

Sep 1986 3 12-13 Under 1 1-2 92

Oct 1986 1-2 71 Under 1 1 92

Dec 1986 10-38 83 89 43 92

It must be noted that the typical odor of sewage was detected occasionally. Also, foaming by surfactants was seen a few times. Although these

phenomena were not common, dosage with antifoaming agents has been implemented. No action has been taken to correct the odor.

Chemical Parameters

Results of the chemical analyses are summarized in Table 3. The secondary effluent discharged into the channel at St. 14 was clear, with small values of SS. The values increased with distance downstream. The maximum value

observed was more than 100 mg/t, and the average was 47.3 mg/t in St. 8.

Contrary to SS, no significant increase or decrease was noted for organic

parameters such as BOD, CODMn, and TOC. The BOD ranged from 10 to 15 mg/i,

and TOC was ca. 10 mg/i throughout the channel studied. The increase in SS,

therefore, could be attributed to the increase in inorganic substances along

the flow of water downstream. It is most likely that erosion or resuspension

52
TABLE 3. SUMMARY OF CHEMICAL ANALYSIS (CONCENTRATIONS

IN MILLIGRAMS/LITRE)*

Station

Parameter 14 13 11 10 8

pH 6.8 7.1 7.2 7.2 7.2

DO 5.4 6.5 7.1 6.6 6.3

SS 4.7 24.4 37.9 38.2 47.3

COD Mn 10.3 10.2 11.8 11.9 12.6

BOD 12.0 12.6 15.8 15.8 14.5

TOC 9.0 8.7 9.3 9.6 9.8

DOC 7.8 7.9 8.4 8.2 7.9

T-P 1.88 1.76 1.89 1.80 1.89

PO4-P 1.36 1.25 1.17 1.14 1.12

T-N 12.3 12.8 12.4 14.1 12.4

NH 4-N 5.1 4.4 3.9 3.7 3.5

NO2 + NO 3-N 7.4 8.1 8.5 9.2 9.3

* Averaged values for 13 samplings from November 11, 1984, to December 2,

1986.

of clay materials from the bank and bottom of the channel increased the SS

concentration. The current condition of the bank and bottom is not conducive

to maintaining clear water.

Slight increase in pH was noted, whereas the water was neutral. Dissolved oxygen (DO) concentration was low at the point of discharge and increased gradually downstream. However, low DO values were observed throughout

the channel, and percent of saturation ranged from 50 to 80.

Although no remarkable changes in nitrogen and phosphorus concentrations

were noted, ammonium nitrogen decreased and nitrite plus nitrate nitrogen

increased gradually downstream by nitrification. It must be noted that the

relatively high rate of nitrification was noted even in winter because water

temperature in the channel was high, i.e. 10° C or more even in the morning,

under a low atmospheric temperature of 3.20 C.

53
Hygienic Parameters

Numbers of coliform groups and fecal colis in the water are listed in

Table 4. The number of coliform groups at the point of discharge, St. 14, met

the water quality standard of class A for the living environment in Japan,

i.e, less than 1,000 per 100 ml. Although the numbers increased in stations

downstream, they could satisfy the standard for class B.

TABLE 4. NUMBER OF COLIFORM GROUPS AND FECAL COLIS

IN THE WATER (COUNTS PER 100 ML)

Station

Parameter 14 13 11 10 8

Coliform groups

Feb. 17, 1986 5.9 x 101 4.0 x 102 2.0 x 103 1.4 x 10 3 1.4 x 103

Apr. 25, 1986 9.3 x 101 5.0 x 102 1.5 x 103 3.2 x 103 4.2 x 10 3

Sep. 5, 1986 1.2 x 102 5.7 x 103 7.0 x 103 9.4 x 103 9.7 x 103

Fecal colis

Nov. 11, 1984 3.4 x 101 2.9 x 102 1.4 x 102 2.3 x 102 2.0 x 102

Feb. 17, 1986 4.3 x 101 3.1 x 102 1.3 x 103 1.2 x 103 7.2 x 102

Apr. 25, 1986 1.0 x 101 1.0 x 102 2.6 x 102 4.9 x 102 8.6 x 102

Sep. 5, 1986 9.3 x 101 1.7 x 103 4.6 x 103 5.8 x 103 6.7 x 103

The number of fecal colis is regarded to be a more reliable indicator of

bacterial contamination and is now used to check the safety of coastal and

lakeside beach resorts for bathing. The guideline number is now less than

100 per 100 ml but will accept 400 per 100 ml. Based on these criteria, discharged iwater at St. 14 is acceptable. Although figures for some stations

downstream were above the allowable level, the water in this channel does not

have to meet the requirements of a bathing resort. It may be concluded that

the water is safe for regular activities around the channel from the standpoint of hygiene.

Periphyton

The periphytic species that appeared in 65 samples collected during the

2.5-year period (13 samplings) are listed in Table 5. The value in parentheses after the name of the species is the number of samples in which the

cell number of corresponding species was more than 104 /mm2 . The total numbers

of species identified were 5 for Cyanophyceae, I for Rhodophyceae, 41 for

Bacillariophyceae, and 9 for Chlorophyceae.

54
TABLE 5. PERIPHYTON COLLECTED FROM THE NOB IDOME CHANNEL

Family Species

Cyanophyc eae ChroococcuB sp.- (5)*

FishereZ~a sp.

Osciiiatoria sp.

Phor'midiwn sp. A

Pho'raidium sp. B

Rhodophyceae Auaowzinel~la cha lyaea (1)

Bacillariophyceae Achnamthes hungarica

A. Zamceolata

A. microcephala

A. minutissima

A . sp.

Amphora sp.

Cer'atoneis arcus var. vauchei'iae

Cocconeis placentula var. lineata

Cymbelia mihnuta

Fragi Lana capucina (1)

F. producta

F . sp.

Frustlia vulgaris

Gomphonema angustatwoG. intricatwm var. pumita

G. parvulwn (6)

G.- pseudoaugur (2)

G. sp.

Nantzschia amphiorxjs

Me Zosira varians

Navicula crn,#ptocepha la

N. fruga~is

N. goeppertiana (3)

N. gregaria (1)

N. seminulwn (31)

N. syimmetrica

N. yuraensia

N. veneta (5)

N. sp.

Nitzschia amphibia

N. frustulurn var. perpusilla

N. gandersheimiensis

N. Zinearis

N. pa lea (5)

N. romana

N. sp.

Pinnularia braunji

P. gibba var. parva

SurireZZa angustata

Synedra ulna

S. ulZna var. oxyrhynchus

Chlorophyceae Ankistrodesmus sp.

Chlamydomonas app.

Chlorococcum sp.

Cladophora glomeratc

Coleochaete sp.

Qedogoniwn sp.

Scenedesmus sp.

Stigeoclonitim sp. (11)

Ulothrix sp.

*Number of samples in which cell number was more than 10 4I/m

55
The dominant species was Navicula seminulum. In 31 of the 65 samples,

their cell numbers were more than 104 /mm2 . The other dominant species and

numbers of samples with more than 10 4 /mm2 were Stigeocloniwn sp. (11 samples);

Gomphonema parvulm (6); and Chroococcus sp., Navicula veneta, and Nitzschia

palea (5). However, the population densities observed were far smaller than

those observed in experimental artificial channels where secondary effluent

was discharged (Ohtake, Aiba, and Sudo 1978).

These species are regarded to be the typical and most common species in

polluted rivers where BOD values are more than 10 mg/j (Fukushima 1987). They

are tolerant species for organic pollution and are frequently used as biological indicators of pollution (Lange-Bertalot 1979). It is also known that more

than 100 algal species can be identified from nonpolluted streams (O'Quinn and

Sullivan 1983, Wehr 1981). The fact that only 56 species were identified

seems to be due, in part, to the environmental condition, the water temperature and flow rate, and the channel stability. However, it must be admitted

that the channel is not in a state that could be called "clear stream" but is

a typical polluted stream, based on the periphytic indicator.

Temporal and aerial distributions of the two dominant species,

Navicuta seminulum and Stigeoclonium sp., are shown in Table 6. Navicula

seminulum, which is known to grow both under high and low light intensities,

appeared in all stations studied irrespective of lighting condition (Hynes

1972). Stigeoclonium sp., which favors high light intensity, appeared mainly

in stations with relative light intensity of 50 percent or more.

TABLE 6. TEMPORAL AND AERIAL DISTRIBUTIONS OF NAVICULA SEMINULUM AND

STIGEOCLONIUM SP.

Date

1984 1985 1986

Species Station Dec Apr Jun Aug Nov Feb A M Jun Jul Sep Oct

Navicula 14 *** *** *** *** ** *** *** *** *** *** *** **

seminuZlw 13 *** *** * * * *** ***   **  *** *

11 * *** * * ** *** ** *** ** * *

10 * *** ** * ** *** *** ** * ** * 8 * *** *** *** ** *** *** *** *** *** ** **

Stigeoclonium sp. 14 * *** * * *** *** * * * ** *

13 * *** *** * ** ** * * * *

11 *** * ** * ** * *

10 *** ** * ** ** ** * * * 8 ** *** *** ***   **  ***   **  *

Note: The number of cells per square millimetre is represented by the following

symbols: * (<103), ** (between 103 and 10 4), *** (>104).

56
Figure 2 shows seasonal variations of total cell numbers of periphyton in

St. 14, 11, and 8. Both in St. 14 and 11, algal population density increased

from winter to spring and decreased in summer, whereas higher population density was observed even in summer in St. 8. The variation in St. 14 and 11

corresponds well with the variation of relative intensity of light shown in

Table 2, i.e., high intensity after leaf fall increased the population density, and low intensity in summer decreased the population density (Summer and

Fisher 1979).

2000 [St. 14

1000 St. 11

50St. 8

500.

x

-100"

U

50-

0

z

1011u

Nov Feb Apr May Jun Jul Sept Oct Dec

1985 1986

Figure 2. Seasonal variations of periphyton in

the Nobidome Channel

The effect on light intensity of deciduous trees along the channel seems

to be one of the major factors controlling population density and species

composition of periphyton. It is likely that periphyton pollution potential

would be worse without the light-shielding effect of trees.

Numbers of periphyton on the surface of clay and gravel in the same stations are shown in Figure 3. Although total population varied among stations,

population density on the clay surface was 50 percent or less compared with

the surface of gravels. As shown in the increase in SS downstream, the surface of clay in the bottom is always eroded; thus, the clay is not a stable

substrate for algal growth. The natural surface of the clay bottom may be

another factor controlling population density.

Benthic Invertebrates

Benthic invertebrate species collected from the channel are listed in

Table 7. There were nine insects and seven other small invertebrates.

Chironomidae were the most common insects. It must be noted that the population density decreased from spring to autumn, after an insect growth regulator

57
1000

• Gravel surface

clay surface

Feb. 1986 Dec. 1986

* 100I

0

W

10I

- ":" S10 ::-' " -

z ..... ...'

14 11 8 14 13 11

Station

Figure 3. Number of periphyton on gravel

and clay

TABLE 7. BENTHIC INVERTEBRATES COLLECTED

FROM THE NOBIDOME CHANNEL

Type Species

Insects Chironomus yoshimatui

Glyptotendipes sp.

Chironomidae Gen. sp. 1-8

Swniliwn uchidai

Psychoda alternata

Cheumatopsyche brevi lineata

Antogaster siebordii

Odonata sp.

Baetis sahoensis

Others Asetlus hi7~gendorfii

Gamnarus nip ponensis

Physa acuta

Erpobdellidae Gen. sp.

Branchiura sowerbyi

Tubifex sp.

Nais sp.

58
was applied to satisfy the complaints of residents about flies. Representative species, such as Chironomus yoshimatui, are well known as pollutiontolerant species. They can live even under high BOD values, as much as

70 mg/k (Kaneda and Kobayashi 1986). This biological indicator also demonstrates that the channel must be regarded as polluted.

CONCLUSIONS

Comprehensive surveys of water quality and benthic invertebrates were

conducted in the Nobidome Channel, into which filtered secondary wastewater

was introduced to restore the waterfront. Specific conclusions were as

follows:

a. Suspended solid concentration increased downstream along the flow by

the erosion of the bank and clay bottom, and the channel could not be

maintained as clear running water. Self-purification was not noted

for organic substances.

b. Dominant species of periphyton and benthic invertebrates were typical

of polluted streams and coincided with poor water quality in the

stream. Standing crops, however, were less than those observed in

experimental channels receiving secondary effluent. Major controlling factors were the light conditions controlled by the growth

and fall of leaves from the deciduous broad-leaved trees along the

channel and the stability of the bottom sediments. Distribution of

Chironomidae was strictly controlled by the repeated dosage of

growth-inhibition chemicals.

REFERENCES

Fukushima, S. 1987. "Relationship Between Organic Bottom Sediments and

Organisms in Rivers--Periphyton" (in Japanese), Report from Yokohama Institute

for Environmental Studies, Vol 74, pp 57-78.

Hynes, H. B. N. 1972. The Ecology of Running Water, Liverpool University

Press, Liverpool.

Japan Environment Agency. 1984. "Survey on Waterfront Conservation Activities in Japan" (in Japanese), Tokyo Association of Environmental Clean-up,

Tokyo.

Kaneda, S., and Kobayashi, N. 1986. "Benthos in Urban River in Yokohama,"

Report for Pollution Control in Yokohama, Vol 126, pp 85-107.

Lange-Bertalot, H. 1979. "Toleranzgrenzen und populationdynamik benthischer

diatomeen bei unterschiedlich starker abwasserblastung," Arch. Hydrobiol.,

Supplement 56, pp 184-219.

Ohtake, H., Aiba, S., and Sudo, R. 1978. "Growth and Detachment of Periphyton in an Effluent from Secondary Treatment Plant of Wastewater," Japanese

Journal of Limnology, Vol 39, pp 163-169.

Ooe, M. 1986. "Plans for the Conservation of Waterfront" (in Japanese),

Japanese Journal of Water Pollution Research, Vol 9, pp 128-134.

59
O'Quinn, R., and Sullivan, M. J. 1983. "Community Structure Dynamics of

Epilithic and Epiphytic Diatoms in a Mississippi Stream," Journal of Phycolog, Vol 19, pp 123-128.

Summer, W. T., and Fisher S. G. 1979. "Periphyton Production in Fort River,

Massachusetts," Freshwater Biology, Vol 9, pp 205-212.

Tokyo Metropolitan Government. 1984. "The Nobidome Channel--Restoration of

Clear Stream" (in Japanese).

US Environmental Protection Agency. 1976. "Methods for Chemical Analysis of

Water and Wastes," EPA-625/6-74-003a, pp 168-172.

Wehr, J. D. 1981. "Analysis of Seasonal Succession of Attached Algae in a

Mountain Stream, the North Alouette River, British Columbia," Canadian Journal

of Botany, Vol 59, pp 1465-1474.

60
AD-POOG --830

LONG-TERM MANAGEMENT STRATEGY FOR DREDGED MATERIAL

RELOCATION OR DISPOSAL

N. R. Francingues, Jr.

Environmental Laboratory

US Army Engineer Waterways Experiment Station

Vicksburg, Mississippi 39181-0631

ABSTRACT

The Corps of Engineers (CE) has taken a major

step in developing a technically sound strategy for

management of dredged material. This strategy is intended to be applicable to the wide range of materials

that are dredged in Federal navigation projects and

other waterways throughout the Nation. This paper

presents an overview of the technical management

strategy with emphasis on the steps required to develop appropriate alternatives for the placement, relocation, or disposal of dredged material. The guidance and appropriate testing and evaluation procedures

incorporate the state of knowledge acquired by the CE

and others worldwide in the dredging and long-term

management of clean, contaminated, and toxic sediments. The CE is refining the technical management

strategy and has performed selected field evaluations

to demonstrate the appropriateness of the strategy.

Interim results of the field verification studies are

also discussed in this paper.

INTRODUCTION

The National Dredging Program includes the maintenance and development of

approximately 25,000 miles (40,000 km) of Federal waterways that flow through

42 states and serve 130 of the Nation's largest cities. Most of the navigation channels in the waterways require periodic dredging to maintain safe and

efficient operating conditions for maritime traffic. Only one estuary,

Puget Sound in the State of Washington, has sufficient natural depth to accommodate large ships engaged in commercial international maritime activities.

Thus, due to the significant economic and defense importance of this extensive

navigation system, it is usually not a question of whether to dredge, but

rather, how to effectively dredge and relocate or dispose of the dredged material in an environmentally acceptable yet economic and efficient way.

Because terminology is important to convey the proper connotation, the

XXVI International Congresses on Navigation (1985) passed a resolution that

addressed the negative impact of terminology such as the use of the term

"spoil" instead of the more positive term "dredged material." Recognizing the

61 92-16014 I IH IIImlHimlg I~ I~ !llli
importance of this matter, interchangeable words such as "placement" and "relocation" are introduced in the text of this paper to supplement the traditionally used word "disposal."

Obviously, there is a critical need to develop a logical, technically

valid, and systematic approach to evaluate relocation or disposal alternatives

for dredged material. Since the nature and level of contamination in sediment

vary greatly on a project-to-project basis, the appropriate method of disposal

or placement may involve any of several options. Control measures to manage

specific problems associated with the presence or mobility of contaminants may

be required as a part of any given alternative. Further, many states, in an

effort to fully manage their natural resources, expect CE assistance via a

long-term approach to operating and managing dredged material relocation areas

and providing additional storage capacity.

An overall long-term management strategy for dredged material, therefore,

is required. Such a framework for decisionmaking must include a technical

management strategy with appropriate testing protocols and design procedures

to aid in selecting the best possible relocation or disposal options and to

identify appropriate control measures to offset any problems associated with

the presence of contaminants (Francingues and Palermo 1984).

The diversity of relocation alternatives and techniques for managing

dredged material requires a comprehensive yet flexible strategy for selecting

environmentally and cost-effective placement or disposal options (Palermo

et al. 1986). The selection of an appropriate strategy will depend on a

variety of factors Including:

a. Project size.

b. Available dredging equipment and placement techniques.

c. Physical characteristics of dredged material.

d. Nature and level of contaminants present.

e. Site-specific placement conditions.

f. Technical feasibility of relocation alternatives.

Potential environmental impacts of relocation operations.

h. Economics.

i. Social, political, and regulatory considerations.

TECHNICAL MANAGEMENT STRATEGY

The two major features of the technical management strategy are consideration of placement or disposal options and steps required for selection and

implementation of appropriate dredged material management practices (see Figure 1) (Francingues et al. 1985). The required steps are as follows:

a. Conduct an initial evaluation to assess contamination potential.

62
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42 4,

00

00

40~ ~ ----- -- , 4
b. Select a potential placement or disposal option.

c. Identify potential problems associated with that option.

d. Apply appropriate testing protocols.

e. Assess the need for placement or disposal restrictions.

f. Select an implementation strategy.

&. Identify available control alternatives.

h. Evaluate design considerations for technical and economic

feasibility.

i. Select appropriate control measures.

Each step of the strategy will be discussed in the following paragraphs.

Conduct an Initial Evaluation

The initial screening for contamination is designed to determine if there

is reason to believe the sediment contains any contaminants in forms and concentrations that are likely to cause degradation of the environment, including

potential availability to organisms in toxic amounts. This screening procedure also identifies specific contaminants of concern in a site-specific sediment, so that subsequent testing and analyses are focused on the most

pertinent contaminants.

Initial considerations may include but are not limited to:

a. Potential routes by which contaminants could reasonably have been

introduced to the sediments.

b. Data from previous bulk sediment analysis and other tests of the

material or other similar material in the vicinity, provided the comparisons are still appropriate.

c. Probability of contamination from agricultural and urban surface

runoff.

d. Spills of contaminants in the area to be dredged.

e. Industrial and municipal waste discharges.

f. Source and prior use of dredged material.

•. Substantial natural deposits of minerals and other natural

substances.

Select a Potential Placement Option

The two major placement or disposal options identified in Figure I are

aquatic (subaqueous) and upland. A number of variations exist for each of the

64
major options, each having some influence on the fate of contaminants at disposal sites. Environmentally sound placement or disposal of dredged material

can be achieved using any of the major options if appropriate management practices are used. The selection of a relocation option should be based on evaluation of specific contaminant problems using accepted testing methodology and

procedures designed specifically for dredged material evaluations. Research

and experience have shown that, in most cases, procedures developed to evaluate disposal practices for industrial waste, domestic sewage, etc., are not

applicable to the assessment of dredged material.

Identify Potential Problems

Each placement option may pose potential problems for managing contaminated dredged material. Potential contaminant problems can be identified

after the initial evaluation and consideration of site-specific conditions,

dredging methods, and anticipated site use. For aquatic sites, contaminant

problems may be either water quality related (water column) or sediment

related (benthic environment). For upland sites, potential contaminant problems may be either water quality related (effluent, surface runoff, or leachate), contaminant uptake related (plants or animals), or air related (gaseous

emissions).

Apply Appropriate Testing Protocols

The magnitude and potential impacts of specific contaminant problems must

be evaluated using appropriate testing protocols. Such protocols, designed

for evaluation of dredged material, consider the unique nature of dredged material and the physicochemical conditions of each relocation or placement option under consideration. The type of testing of the contaminated sediment to

be dredged depends on which of the questions in Figure 2 is being addressed.

Testing intended to answer the question "Where should sediment be placed

to minimize contaminant mobility?" is site selection testing and addresses the

situation in which aquatic sites as well as upland or nearshore confined sites

are available. The emphasis is on selecting the most appropriate environment

for the placement of dredged material.

Testing intended to answer the question "Is the available site acceptable

for dredged material?" is acceptability testing and addresses the situation

where there are limitations on available sites. Therefore, the sediment is

tested to determine the acceptability of a given site for the placement or

disposal of the sediment. For example, if the only sites available are confined inland sites, then testing should focus on upland environments and not

on aquatic environments. Ultimately, the testing should be tailored to the

available relocation or disposal site.

Assess Need for Placement or Disposal Restrictions

The results of all testing are compiled and evaluated to determine the

-otcntial fcr cnvironmental harm from contamination, to examine the interrelationships of the problems and potential solutions, and to determine what

restrictions or controls on aquatic placement or upland placement are appropriate. If impacts as evaluated by the testing protocols are acceptable, traditional aquatic or upland placement may again be considered.

65
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Select an Implementation Strategy

Specific environmental problems identified by the testing protocols must

be considered in the development of an implementation plan appropriate for

dredged material and appropriate for the level of potential contamination.

Certain strategies may be eliminated from consideration due to restrictions

and local authority decisions or agreements.

Identify Available Control Alternatives

Several alternatives may be available for the selected implementation

strategy. Alternatives for controlling water column and benthic impacts

include bottom discharge via submerged diffusers, treatment, confined aquatic

disposal, and subaqueous capping using cleaner sediment. Alternatives for

controlling confined disposal impacts include treatment, long-term relocation,

and dredged material reuse.

FIELD VERIFICATION AND APPLICATION

Several examples can be cited where the CE has applied the technical management strategy to assist in the evaluation of dredged material disposal or

relocation. For example, applications for Puget Sound, in the State of

Washington, include the Commencement Bay Superfund project, the Puget Sound

Dredged Disposal Analysis (PSDDA) study, and the US Navy Homeport facility at

Everett, Wash.

To provide assistance in interpreting test data on dredged material and

in making decisions associated with the high cost of remedial action, a decisionmaking framework was developed for proposed dredging in Commencement Bay

(Lee et al. 1985). The framework focuses on procedures for answering the

questions of how dredged material should be tested and how the results should

be interpreted to determine the degree of potential contaminant mobility and

the placement option that would have the least adverse impact on the overall

environment.

Also, as part of the PSDDA study, the second component of the technical

management strategy was developed to assist in evaluating various dredging,

transportation, and disposal alternatives for contaminated dredged material

(Cullinane et al. 1986). These guidelines provided a strategy for selecting

control and treatment options for contaminated dredged material that requires

restrictions. This "dredged material alternative selection strategy" is intended to provide a general approach to selection while allowing as much detail as possible to guide decisionmakers through the process of formulating

and choosing an appropriate dredging/transportation/disposal alternative.

The initial field application of the technical management strategy in

Puget Sound was to dredging for the Navy Homeport facility at Everett, Wash.

In June 1984, the Navy contracted with the CE to provide technical assistance

for dredging and disposal of the dredged material. The CE applied the suite

of tests specified in the strategy to assess the requirements for dredged

material placement or disposal. Results of the tests have been critical to

decisionmaking and final design of the Navy's dredging plans.

67
In addition to the Puget Sound application, the CE has applied appropriate portions of the technical management strategy to several key projects.

These projects include the Indiana Harbor Canal in the Chicago District, the

Corps/US Environmental Protection Agency Field Verification Program at Bridgeport, Conn., and the New Bedford Superfund site at New Bedford, Mass. Results

of these efforts are being used to further refine the technical aspects of the

overall management approach.

SUMMARY

A technically feasible and environmentally sound management approach to

the relocation or disposal of dredged material has been developed and presented. This strategy is based on results from many years of research and on

dredging experience worldwide. The evaluative procedures allow specific

potential problem areas to be defined and addressed. A number of variations

are presented for each of the major options of aquatic, intertidal, nearshore,

and upland placement, each having a significant influence on the fate of contaminants at relocation sites. The strategy provides a framework for choosing

an appropriate alternative for placement or disposal based on specific problem

areas. It is applicable to materials ranging from clean sand to highly contaminated sediments.

REFERENCES

Cullinane, M. J., Averett, D. E., Shafer, R. E., Male, J. W., Truitt, C. L.,

and Bradbury, M. R. 1986. "Guidelines for Selecting Control and Treatment

Options for Contaminated Dredged Material Requiring Restrictions," Final

Report, Puget Sound Dredged Disposal Analysis, US Army Engineer District,

Seattle, Washington State Department of Natural Resources (Ecology), and USEPA

Region 10, Seattle, Wash.

Francingues, N. R., Jr., and Palermo, M. R. 1984. "Management Strategy for

Disposal of Dredged Material; Vol 1, Dredging and Dredged Material Disposal,"

Proceedings of Conference Dredging 84, American Society of Civil Engineers,

November 14-16, 1984, Clearwater Beach, Fla.

Francingues, N. R., et al. 1985. "Management Strategy for Disposal of

Dredged Material: Contaminant Testing and Controls," Miscellaneous Paper

D-85-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Lee, C. R., Peddicord, R. K., Palermo M. R., and Francinques, N. R., Jr.

1985. "Decisionmaking Framework for Management of Dredged Material: Application to Commencement Bay, Washington," US Army Engineer Waterways Experiment

Station, Vicksburg, Miss.

Palermo, M. R., Francingues, N. R., Lee, C. R., and Peddicord, R. K. 1986.

"Evaluation of Dredged Material Disposal Alternatives: Test Protocols and

Contaminant Control Measures," Proceedings of WODCON XI (Eleventh World Dredging Congress), Brighton, United Kingdom.

XXVI International Congresses on Navigation. 1985. "Subject No. 3, Engineering on Sandy Coasts, Recent Developments and Experience on Design and Execution of Beach Nourishment Techniques and Equipment, Including Specific Measures on Both Sides of Harbor Entrances Such as Bypassing," Brussels, Belgium.

68
REMOVAL OF NITROGEN AND REFRACTORY ORGANIC COMPOUNDS IN

MUNICIPAL LANDFILL LEACHATE BY SEQUENCING BATCH

REACTOR ACTIVATED SLUDGE PROCESSES

M. Hosomi, K. Matsusige, Y. Inamori, R. Sudo

National Institute for Environmental Studies

Yatabe-machi, Tsukuba, Ibaraki 305, Japan

M. Okada

Tokyo University of Agriculture and Technology

Naka-machi 2-24-16, Koganei, Tokyo 184, Japan

K. Yamada and Z. Yoshino

__ Science University of Tokyo

Kagurazaka 1-3, Shinjuku-ku, Tokyo 162, Japan

ABSTRACT

L Laboratory-scale experiments on aerobic/

anaerobic operations of the sequencing batch reactor

(SBR) activated sludge processes, in which methanol was

added as a hydrogen donor, were conducted to remove

nitrogen and refractory organic compounds in municipal

landfill leachate. The NH 4-N concentrations in leachate from landfill ranged from 100 to 200 mg/t. A high

concentration of nonbiodegradable organic compounds

(100 to 150 mg/i as chemical oxygen demand (COD)) was

observed in the leachate. Ninety-five percent or more

nitrogen removal was achieved in the operation with an

optimum length of aerobic and anoxic/anaerobic period

for the nitrification-denitrification process. Fifty

percent or more removal of refractory organic compounds was achieved by the SBR activated sludge process with the addition of ozonation pretreatment.

INTRODUCTION

An increasing amount of municipal and industrial solid waste is being

disposed. This waste is incinerated, shredded or baled, and then landfilled.

The landfill sites discharge large amounts of leachate that contains nitrogen

and refractory organic compounds, resulting in the pollution of ground water

(subsurface formations and aquifers) at the landfill sites (Robertson,

Toussaint, and Jorque 1974; US Environmental Protection Agency 1978). It is

urgent, therefore, that this situation be remedied by establishing an effective method of treating leachate that contains high concentrations of nitrogen

and refractory organic compounds.

There are two types of methods to reduce the nitrogen in leachate:

(a) biological treatment consisting of nitrification-denitrification processes

69 92-16015
and (b) physical and chemical treatment. The first type is considered preferable because it costs less, produces N2 gas as the final product, and can

effectively treat nitrogen in various forms. Existing leachate treatment

facilities at land disposal sites have been making use of rotating biological

contactors, a biological filter method, because of the ease of maintenance and

the nitrification efficiency. The most significant problem with this method

is that salt in the leachate accumulates on the surface of disks and the

rotary shaft as scales of gypsum and calcite, deteriorating the efficiency of

treatment and power consumption and damaging the rotary shaft (personal communications, S. Matsui, 1984, and Y. Matsufiji, 1985). The second type is expensive, may result in another kind of pollution (i.e., the production of

chemical sludges and increased NH4 -N gas concentration in air by ammonia

stripping), and is capable of treating nitrogen in only limited forms (i.e.,

the breakpoint method can treat only NH 4-N in water).

The SBR activated sludge process with biological nitrificationdenitrification has the following advantages: the device is less likely to be

damaged by scales; maintenance is easy; sludge bulking is not likely; a wide

range of pollutant load can be treated by selecting operations suitable for

the pollution load (such as the time in a cycle and the length of aerobic and

anaerobic period); and nitrogen and phosphorus can be removed at the same time

(Goronszy 1979; Irvine and Busch 1979; Irvine, Miller, and Bhamrh 1979; Dazai,

Fuutai, and Takahara 1982; Silverstein and Schroeder 1983; Okada and Sudo

1985). Also, it is said that even some nonbiodegradable halogenated organic

compounds can be degraded by a biological treatment through the denitrification process under anoxic conditions (Bouwer and McCarty 1983). These are

some of the reasons why the SBR activated sludge process is attracting so much

attention for leachate treatment at landfill sites.

On the other hand, ozonation treatment, known to be effective for disinfection and the oxidation of organic compounds, has been found satisfactory

for transforming high molecular weight compounds to low molecular weight compounds and also for increasing the biodegradability of organic substances

(Glaze et al. 1982; Peyton et al. 1982; Sakumoto et al. 1984; Jones, Sakaji,

and Daughton 1985). It is expected, therefore, that the SBR activated sludge

processes will work more effectively for refractory organic compounds when

used with pretreatment by ozonation.

Laboxatory-scale experiments were conducted on aerobic and anoxic/

anaerobic operations of the SBR activated sludge processes for leachate from a

land disposal site to examine the effectiveness of this method in reducing the

high concentration of nitrogen and refractory organic compounds contained in

the leachate. The following points are discussed:

a. Seasonal changes in the chemical composition of the leachate from

landfill sites.

b. The effectiveness of the SBR activated sludge processes combined with

the Bringmann method (Sudo 1977), in which methanol is added to the

leachate as a hydrogen donor, for removing the nitrogen in the leachate from the landfill site.

70
c. Comparative analysis of the effectiveness of two different methods

(the SBR activated sludge processes with and without pretreatment by

ozonation) in degrading refractory organic compounds.

EXPERIMENTAL PROCEDURES

Sampling and Chemical

Analysis of the Leachate

The chemical composition of the leachate was examined every 10 days at a

municipal landfill site, where noninflammable waste (plastics, glass, largevolume rubbish, etc.), sludge, and ash of food waste are disposed.

Table 1 shows the chemical properties measured and the methods used in

analysis of the leachate (Japan Sewage Works Association 1985, Hosomi and Sudo

1986).

TABLE 1. METHODS FOR CHEMICAL ANALYSIS OF WASTEWATER

Property Methods

Biological oxygen demand (BOD) 5-day BOD using the azide modification of

the iodometric method

Chemical oxygen demand (COD) Acid-potassium-permanganate method at

1000 C

Total organic carbon (TOC) TOC analyzer

Dissolved oxygen (DO) Azide modification of the iodometric

method

pH pH meter

Alkalinity Potentiometric titration to end-point pH

NH 4-N Automated phenate method

(NO2 + NO3 )-N Automated cadmium reduction method

PO4- P Automated ascorbic acid method

Total nitrogen (T-N), Simultaneous determination of T-N and T-P

total phosphorus (T-P) using persulfate digestion

Suspended solids (SS) Glass-fiber filter method

Mixed-liquor suspended solids Nonfilterable residue of a well-mixed

(MLSS) sample of the suspension

Na, K, Mg, Ca Inductively coupled argon plasma atomic

emisoion spectrometry

71
Nitrogen Removal by the

SBR Activated Sludge Processes

Experimental Apparatus

Figure I shows the apparatus used in the study. The reactor is a 10-i

glass bottle with a diffuser pipe and drain valve. An air pump is attached

for aeration, and a magnetic stirrer for mixing. The reactor was kept in a

thermostatic chamber at 200 ± 20 C.

0

A Sequencing batch reactor

A B C B Diffuser pipe

C Discharge and waste sludge

D Air pump

E Magnetic stirrer

F F Drain valve

Figure 1. Experimental apparatus for SBR

activated sludge processes

Chemical Analysis of Treated Water

The same sample that was used for chemical analysis of the leachate was

used as the influent of the SBR activated sludge processes. The sample was

kept at 100 C until start-up of the SBR. Figure 2 shows the operational

schedules. Runs 1-5 comprised preliminary study, for the purpose of determining appropriate operational conditions for removing nitrogen in the leachate.

The result of Runs 1-5 was applied to Run 6 to affirm the efficiency of nitrogen removal from the leachate by the SBR. In Run 7, the NH4-N loading was

increased to further analyze the nitrogen removal efficiency of the SBR.

The chemical composition of the effluent and the water phase of mixed

liquor of activated sludge in each run was measured by the analytical methods

listed in Table 1.

Removal of Refractory Organic

Compounds with Ozone Pretreatment

Figure 3 shows the experimental apparatus for ozonation (Labo7O, Communitor Service). The ozonation reactor is a 10-k cylindrical Plexiglas container

with a height of 120 cm and a diameter of 12 cm. The air inflow was 170 k/hr;

the ozonizer power was 120 W; the reaction period was 30 min; and the reaction

temperature was 100 C.

The same sample as described above for the nitrogen removal analysis was

used. The sample leachate was first ozonated and then treated in the SBR.

The operational schedules were the same as for Runs 6 and 7 described above.

72
NH 4-N Loading Methanol Addition

RUN NO. kg NH4 -N/mn3 /day g CH3OH/mn3 /day

1ANMM 0.02 0

18 3 3hr

2 A. M MS 0.05 0.14

18 4 2hr

Ts ANIS JA,MI S AJMS 0.10 0.14

2 4 4 4 4 4 2 hr

4 TANIM AM M H 0.10 0.13

6 6 6 4.5 1.5 hr

5 Tý I-MI A3NE 0.05 0.25

2 6 4 10 2hr

6 jjII3 MiI ANI Ij 0.03 0.19

2 6 4 10 2 hr

V [jý 0.11 0.38

2 6 6 a 2 hr

F- Mixing V Fill

WA I Aeration 7 Draw

51 Settling f Methanol addition

Figure 2. Operational schedules for the SBR activated sludge processes

73
A AD A Ozonizer

8 Air pump

C Reactor

'BD Inflow of coolingl water

F E Outflow of ozone and air

F Clip

G Diffuser pipe c H Drain valve

SI I Discharge

H

Figure 3. Experimental apparatus for ozonation

RESULTS AND DISCUSSION

Seasonal Changes in Chemical

Composition of the Leachate

Figure 4 shows the seasonal variations in the concentrations of BOD, COD,

TOC, and SS of the leachate. Figure 5 shows those of NH4 -N, NO2-N + NO 3-N

(NO x-N), and T-N. Table 2 presents statistical data on each of the chemical

compositions.

All compositions commonly showed larger values in the summer (JulyAugust) than in autumn (September-November). One possible reason for this is

AI COD 0- TOC

"150 0. BOD 0 SS

' 120 E

0 o ~60

C

J J A S 0 N D J F

s6ess 167

Figure 4. Seasonal variations in the concentration of BOD, COD, TOC, and SS

of the leachate

74
320 A T-N *NOx-N

A• NH4-N

0240- E

160

C

8

0

0 ~S

J J A S 0 N D J F

1066 1067

Figure 5. Seasonal variations in the concentrations of NH4 -N, NOx-N, and T-N

of the leachate

that the concentrations increased in the summer through the evaporative loss

of water caused by higher temperatures and less precipitation. Another reason

may be that the high temperatures accelerated anaerobic decomposition in the

landfill site. The concentrations of COD and NH 4-N also increased in the winter. This is probably because of the lower precipitation in the winter.

The concentration of BOD varied from 13 to 57 mg/i, with an average of

27 mg/i, lower than that obtained at landfill sites where the main waste is

ash (Matsufuji, Hamajima, and Yanase 1982). This indicates that the landfill

site chosen for the experiment had a very small amount of biodegradable organic compounds. The concentration of COD was about 100 mg/t, much higher

than that of BOD. The ratio of BOD to COD was therefore 0.2:0.3, much smaller

than that in domestic wastewater. From these facts, we can assume that the

sampled leachate contained many nonbiodegradable organic compounds, i.e., refractory organic compounds. Thus, considering the extremely small BOD value,

the refractory organic compounds in the sample leachate can be represented by

COD and TOC values.

Total nitrogen varied around 200 mg/i, with a coefficient of variation of

26 percent, greater than the variations in COD and BOD concentrations. The

NH -N accounted for 90 percent of the total nitrogen. Actually, the seasonal 4

change in total nitrogen concentration was consistent with that of NH 4-N concentration, which was high in the summer and winter and low in the autumn,

similar to that of COD concentration, which varied around 170 mg/i. Also, the

W 4-N concentration showed a high correlation with alkalinity, with a coefficient of correlation of 0.85.

Total phosphorus was between 0.33 and 5.8 mg/i. The PO 4-P concentration

75
was about 0.03 mg/i, which shows that most of the phosphorus contained in the

leachate was particulate phosphorus. The ratio of nitrogen to phosphorus was

over 100, much greater than that of domestic wastewater, which indicates that

phosphorus is the limiting nutrient in biological treatment.

The pH showed only a small seasonal variation around 7.8. Alkalinity

showed a large seasonal variation, from 524 to 1,730 mg/t, similar to the

NH 4-N concentrations.

The concentrations of major cations such as Na and Ca were very high, as

shown in Table 2, indicating that scales of gypsum and calcite could easily be

formed.

TABLE 2. WATER QUALITY DATA FOR MUNICIPAL LANDFILL LEACHATE,

MAY 1986-FEBRUARY 1987

Maximum Minimum Average Median S.D. No. of

Parameter mg/k mg/i mg/L mg/J mg/i Samples

COD 158 83.5 114 114 21.5 24

BOD 57 14 26.5 23 10.4 24

TOC 105 51 74.1 71 15.4 24

SS 93 27 52.8 50 19.4 24

NH 4-N 327 93 172 167 57.2 23

NO -N 41 0.36 13.6 8.4 13.6 23 x

T-N 330 107 211 211 55.9 23

PO4 -P 0.13 0.004 0.03 0.020 0.03 23

T-P 5.8 0.33 1.53 0.73 1.79 23

Alkalinity 1,750 524 1,026 922 345 22

pH 8.77 7.35 7.84 7.78 0.33 24

Na 1,683 1,201 1,524 1,638 191 7

K 1,067 786 972 1,010 103 7

Mg 115 86.9 103 101 10.0 7

Ca 133 95.3 114 108 15.0 7

76
Nitrogen Removal

Runs 1-5

In the preliminary study (Runs 1-5), the time in a cycle, the amount of

methanol addition, and the length of each aerobic and anoxic period, i.e., the

length of the mixing periods with and without aeration, were changed from run

to run. The results showed that:

a. The nitrogen was removed little by the Wuhrmann method, which makes

use of the endogenous respiration of activated sludge as a hydrogen

donor to denitrify the contained NO -N. x

b. Enough methanol should be added so that the ratio of methanol to

NH 4-N is greater than 2.5.

c. More than 90 percent of the T-N can be removed, if NH 4-N loading is

less than 0.05 kg NH 4-N/m 3 /day and both the anoxic and aerobic periods are longer than 4 hr.

Run 6

Figure 6 shows the concentration of T-N in the influent and effluent with

the passage of time in Run 6. Run 6a shows the concentration of T-N in the

effluent when no preliminary treatment by ozonation has been conducted on the

influent. Run 6b shows the concentration of T-N in the effluent when an

ozonated sample is used for the influent. In each case, the concentration of

T-N leveled off 10 days later. Table 3 shows the nitrogen concentration in

the influent and effluent and the percent of T-N removal in the steady state

after the passage of this time.

200

S150

S100 C

C) 0 Influent

Z 50 & Effluent(RUN 6a)

I.A Effluent(RUN 6b)

0 -

0 10 20 30

Time, days

Figure 6. Concentrations of T-N in the influent

and effluent in Run 6

77
TABLE 3. AVERAGE INFLUENT AND EFFLUENT DATA FOR RUN 6

DURING STEADY-STATE PERIOD

Effluent

Parameter Influent Run 6a Run 6b

NH4 -N, mg/i 96.4 0.04 0.05

NO -N mg/i 13.8 0.02 0.03 x

T-N, mg/i 107 4.4 3.4

T-N removal, % -- 95.9 96.8

The concentrations of NH 4-N and NO -N in the effluent were less than

4 x

1 mg/i for the influent both with and without ozonation pretreatment. The organic nitrogen concentration was 2 to 5 mg/i. The T-N removal was very high,

at 96 percent in Run 6a and 97 percent in Run 6b.

Figure 7 shows the track data of NH 4-N, NO x-N, and PO4-P concentrations

in the water phase of mixed liquor of activated sludge over a cycle of the

process. The NH 4-N concentration decreased linearly from 31 to I mg/i after

the mixing with aeration started. The NO -N concentration linearly increased x

with the decrease in NH4 -N, from 3 to 30 mg/i, and started decreasing just

m7 A,M M A,M IS

0 NH4-N

3 6 NO-'N

U Po'-p

_M1 Mixing

.20- E Aeration

412Settling

dw V Fill C

0 10

Time, hr

Figure 7. Track data of NH4-N, NOx-N, and PO4-P

concentrations in the water phase of

mixed liquor of activated sludge over a cycle of operation in Run 6a

78
after methanol was added until it became 0 mg/i 4 hr later. The P0 4 -P concentration remained steady at 2 to 3 mg/i, which indicates that the amount of

PO4 -P added can be even less.

Excess sludge was removed only at the time of chemical analysis of water

both in Run 6a and Run 6b. The MLSS concentration was maintained at about

3,500 mg/i.

Run 7

The NH4 -N loading was increased approximately three times that in Run 6..

Figure 8 shows the track data of the T-N concentration in the influent and

effluent water. The influent was not pretreated by ozone in Run 7a, whereas

the influent was ozonated in Run 7b. The T-N concentration decreased from the

beginning and became almost constant 30 days later.

300 -

0 Influent

200

E A Effluent(RUN 7a)

A& Effluent(RUN 7b)

0 100

0

0 10 20 30 40

Time, days

Figure 8. Concentrations of T-N in the influent

and effluent in Run 7

Table 4 shows the average influent and effluent nitrogen concentrations

and percent of T-N removal during the steady-state period. In Run 7a, the

residual NO -N concentration was greater than 11 mg/t, and the percent of T-N x

removal was less than that 'n Run 6 at 91 percent. However, Run 7b showed the

same T-N removal as Run 6, although the NH4-N loading was approximately three

times.

Figure 9 shows the track data of NH4 -N, NOx-N, and the PO4-P concentrations for a cycle of the operation in Runs 7a and 7b. In Run 7a, not all of

the NH4-N was nitrified during the aerobic period. This is because nitrification was inhibited by the decrease in pH value down to 5.2. As a result, less

79
TABLE 4. AVERAGE INFLUENT AND EFFLUENT DATA FOR RUN 7

DURING STEADY-STATE PERIOD

Effluent

Parameter Influent Run 7a Run 7b

NH 4-N, mg/i 215 0.02 0.04

NO -N, mg/i 23.6 11.1 0.23

T-N, mg/t 253 22.6 7.5

T-N removal, % -- 91.0 97.0

nitrogen was removed during the following anoxic period than otherwise, i.e.,

in the case of enough nitrification. Because of this, less alkalinity was

produced during the process of denitrification than supposed.

The average alkalinity and NH 4-N concentration during the steady state in

Run 7 were 1,400 mg/i and 215 mg/i, respectively. Theoretically, 7.14 g of

alkalinity is required to nitrify 1 g of NH4 -N. There was a lack of alkalinity in the water in Run 7. In Run 7b, however, alkalinity slightly increased,

and NH 4-N concentration slightly decreased because of ozonation. Also, more

alkalinity was produced during the process of denitrification than in Run 7b,

which was why the alkalinity was high enough in Run 7b.

In Run 7, the amount of sludge removal was only that necessary for a

chemical analysis of the water phase in mixed liquor, as in Run 6. The MLSS

concentration remained almost constant at around 3,500 mg/i. Solid retention

time ranged from 20 to 50 days, which implies that the sequencing batch treatment of landfill site leachate produces very little excess sludge. Also, protozoa and metazoa such as Philodina and Vorticella, which are dominant in the

flora that appears during this process (Table 5), helped decrease the excess

sludge (Sudo and Aiba 1984).

Table 6 shows the rates of nitrification and denitrification calculated

from the track data of NH4 -N and NOx-N concentrations in a cycle of operation

in Runs 6 and 7. These values are close to those for anoxic and aerobic

sludge from domestic wastewater treatment plants.

Removal of Refractory Organic Compounds

As discussed with regard to seasonal changes in chemical composition,

concentrations of organic compounds determined by TOC or COD in the leachate

should be considered to be mostly nonbiodegradable substances because BOD concentration is very small. Figure 10 shows the performance of Run 6 in removing refractory organic compounds represented by COD and TOC concentrations in

the influent and effluent water. Figure 11 shows the corresponding data for

Run 7. Slightly different conclusions regarding the effectiveness of this

80
"M AN M A,M Is

0 NH"-N

100. 0 NO.-N

, P0O-P

S80 - Mixing

E Aeration

Cr 0 60 Settling ,U

V Fill

C 40

17 Draw

0 20 Methanol addition

0

0 4 8 12 16 20 24

Time, hrs

a. Run 7 a

"I ". IF, I

M -A,M M I A,M IS

10 0 0 NNH-HN N0x-lH

U P0 4-P

80 - 'M Mixing

E 7 A Aeration

C60 0 Settling tFS (- V Fill

S40 C

US•7 Draw

0 20 Methanol

o addition

0

0 4 8 12 16 20 24

Time, hrs

b. Run 7b

Figure 9. Track data of NHt4 -N, NOx-N, and PO4-P

concentrations in the water phase of

mixed liquor of activated sludge over

a cycle of operation in Runs 7a and 7b

81
TABLE 5. MICROFLORA IN SBR ACTIVATED SLUDGE

PROCESSES, RUN 7

Population Number/

mg MLSS

Species Run 7a Run 7b

Small flagellata 139 60

Trachelophyllum pusillwn 35 120

Acineta lacustris 17

Cyclidiwn sp. 295 15

Vorticella microstoma 555 467

Oxytrica sp. 17

Euglypha sp. 17 15

Philodina sp. 35 251

Nematoda sp. 5

TABLE 6. RATES OF NITRIFICATION AND DENITRIFICATION IN

SBR ACTIVATED SLUDGE PROCESSES

Rate of Nitrification Rate of Denitrification

Run No. mg N/g MLVSS*/hr mg N/g MLVSS/hr

6a 2.6 2.6

6b 3.0 3.0

7a 4.7 6.0

7b 4.6 4.9

* Mixed-liquor volatile suspended solids.

method in removing refractory organic compounds can be drawn from the COD- and

TOC-based analyses. However, it can be said that concentrations of both TOC

and BOD in the effluent were in a steady state in each run.

Table 7 shows the performances of Runs 6 and 7 in removing refractory organic compounds. The BOD concentrations of the effluent are 1 to 3 mg/i

whether the leachate was ozonated or not. This means that most of the easily

biodegradable organic compounds in the leachate and methanol added first in

anoxic period were removed. On the other hand, ozonation proved to be

82
I S O 

t o o

ON100 Cosao

E E

C tzz

so 0 nlu n 0 040uen

0 fletRN7)20 0 A Eftluent(RIJN 7a) a Efluen(RUN7a)A Etfluent(RUN 7b) 0 A effluent(RUN 7b) 0

0 10 20 30 40 0 10 20 30 40

Time, days Time, days

Figure 10. Concentrations of COD and TOG in the influent

and effluent, Run 6

0 0 0 Influent

so 80 A Eftluent(RUN 6a)

A Eflf uent(RUN 6b)

60 *s

E E

'J 40 C 40

0

0 *~~ Influent 0jA A

o20 A6 Eftluent(RUN 6a) 020

0 I

0A Etfluent(RUN 6b)

0 0

0 10 20 30 0 10 20 30

Time, days rime, days

Figure 11. Concentrations of COD and TOG in the influent

and effluent, Run 7

TABLE 7. AVERAGE INFLUENT AND EFFLUENT DATA FOR RUNS 6

AND 7 DURING STEADY-STATE PERIOD

Influent Effluent Influent Effluent

Parameter Run 6 Rýun 6a Run 6b Run 7 Run 7a Run 7b

COD, mglt 83.5 52.1 41.1 127 81.5 60.8

COD removal, % - 37.6 50.8 -- 35.8 52.1

TOG, mg/9, 51.7 37.5 29.0 102 65.4 42.6

TOG removal, Z -- 27.5 43.9 -- 35.8 50.1

83
effective in removing COD and TOC. The COD and TOC removals were 50.8 and

43.9 percent, respectively, with preliminary ozonation, compared with 37.6 and

27.5 percent, respectively, without ozonation in Run 6.

Figure 12 shows the results of fractionation by molecular weight by

Sephadex G-50 gel in three different samples: the influent, the effluent

treated by the SBR, and the effluent treated both by ozonation and the SBR.

The figure shows that organic compounds were removed after each treatment. It

is inferred from three different patterns of fractionation by molecular weight

that sequencing batch treatment alone was effective in removing high molecular

weight organic compounds that have a peak at approximately fraction number 7,

and that the combination of ozonation and sequencing batch treatment was effective in removing low molecular weight organic compounds that have a peak

around fraction number 14.

Influent Effluent of SBR Effluent of

SBR÷Ozone

E

0

(o

0

Z

0 10 20 30- 10 20 30 0 10 20 30

Fraction No.

Figure 12. Fractionation by molecular weight by

Sephadex G-50 gel

84
CONCLUSIONS

Laboratory-scale experiments were conducted on aerobic and anoxic/

anaerobic operations of the SBR activated sludge processes with the addition

of methanol as a hydrogen donor to efficiently remove nitrogen and refractory

organic compounds in municipal landfill leachate.

NH 4-N concentrations in leachate from landfill ranged from 100 to

200 mg/i. A high concentration of refractory organic compounds (100 to

150 mg/t as COD) was observed in the leachate. Ninety-five percent or more

nitrogen removal was achieved in the operation with an optimum length of aerobic and anoxic/anaerobic period for the nitrification-denitrification process.

Fifty percent or more removal of refractory organic compounds was achieved by

the SBR activated sludge processes with the addition of ozonation

pretreatment.

REFERENCES

Bouwer, E. J., and McCarty, P. L. 1983. "Transformation of Halogenated Organic Compounds Under Denitrification Conditions," Applied Environmental Microbiology, Vol 45, pp 1295-1299.

Dazai, M., Fuutai, N., and Takahara, Y. 1982. "Development of New Batch

Activated Sludge Process for Bulking Control--Limited Aeration Process,"

Journal of Japan Sewage Works Association, Vol 19, No. 214, pp 17-25 (in

Japanese).

Glaze, W. H., Peyton, G. R., Huang, F. Y., and Burleson, J. L. 1982. "Destruction of Pollutants in Water with Ozone in Combination with Ultraviolet

Radiation; 2. Natural Trihalomethane Precursors," Environmental Science and

Technology, Vol 16, pp 454-458.

Goronszy, M. C. 1979. "Intermittent Operation of the Extended Aeration Process for Small Systems," Journal of the Water Pollution Control Federation,

Vol 51, pp 274-287.

Hosomi, M., and Sudo, R. 1986. "Simultaneous Determination of Total Nitrogen

and Total Phosphorus in Freshwater Samples Using Persulfate Digestion," International Journal of Environmental Studies, Vol 27, pp 267-275.

Irvine, R. L., and Busch, A. W. 1979. "Sequencing Batch Biological Reactor--

An Overview," Journal of the Water Pollution Control Federation, Vol 51,

pp 235-243.

Irvine, R. L., Miller, G., and Bhamrh, A. S. 1979. "Sequencing Batch Treatment of Wastewater on Rural Areas," Journal of the Water Pollution Control

Federation, Vol 51, pp 244-254.

Japan Sewage Works Association. 1985. "Standard Methods for the Examination

of Municipal Wastewater--1984" (in Japanese).

85
Jones, B. M., Sakaji, R. H., and Daughton, C. D. 1985. "Effects of Ozonation

and Ultraviolet Irradiation on Biodegradability of Oil Shale Wastewater Organic Solutes," Water Research, Vol 19, pp 1421-1428.

Matsufuji, Y., Hanajima, M., and Yanase, R. 1982. "Semi-aerobic Landfill

Treatment of Ashes Incinerated," Proceedings of the 34th Conference of the

Japan Society of Civil Engineering, pp 51-52 (in Japanese).

Okada, M., and Sudo, R. 1985. "Performance of Sequencing Batch Reactor Activated Sludge Processes for Simultaneous Removal of Nitrogen, Phosphorus and

BOD as Applied to Small Community Sewage Treatment," IAWRC's First Asian Conference--Treatment, Disposal and Management of Human Waste, pp 375-382.

Peyton, G. R., Huang, F. H., Burleson, J. L., and Glaze, W. H. 1982. "Destruction of Pollutants in Water with Ozone in Combination with Ultraviolet

Radiation; 1. General Principles and Oxidation of Tetrachloroethylene," Environmental Science and Technology, Vol 16, pp 448-453.

Robertson, J., Toussaint, C. R., and Jorque, M. 1974. "Organic Compounds

Entering Ground Water from a Landfill," EPA-660/2-74-07, US Environmental Protection Agency.

Sakumoto, A., Arai, H., Arai, M., and Miyata, T. 1984. "Exhaustive Degradation of Humic Acid in Water by the Simultaneous Application of Radiation and

Ozone," Journal of Japan Water Works Association, Vol 53, No. 10, pp 35-44 (in

Japanese).

Silverstein, J., and Schroeder, E. D. 1983. "Performance of SBR Activated

Sludge Processes with Nitrification/Denitrification," Journal of the Water

Pollutant Control Federation, Vol 55, pp 377-384.

Sudo, R. 1977. Biology in Wastewater Treatment, Sangyouyousuichousakai.

Sudo, R., and Aiba, S. 1984. "Role and Function of Protozoa in the Biological Treatment of Polluted Waters," Advances of Biochemical Engineering and

Biotechnology, Vol 29, pp 118-141.

US Environmental Protection Agency. 1978. "Chemical and Physical Effects of

Municipal Landfills on Underlying Soils and Ground Waters," EPA-600/2-78-096.

86
REGIONAL EFFORTS THROUGH THE IJC TO ADDRESS CONTAMINATED BOTTOM

SEDIMENT PROBLEMS IN THE GREAT LAKES

A. G. Kizlauskas

Great Lakes National Program Office

US Environmental Protection Agency

230 Dearborn Street

Chicago, Illinois 60604

ABSTRACT

C•) The International Joint Commission (IJC) is a bi00• • national (United States and Canada) organizatikn that

was established under the Boundary Waters Treaty of

co• 1909. In 1978, the two countries signed a Great Lakes

Water Quality Agreement, pursuant to the Boundary

____ Waters Treaty. Carrying out the provisions of this

Agreement, the United States and Canada, through the

_._- IJC, are addressing the problem of contaminated bottom

sediments both in the traditional context of dredging projects and in the newer context of the potentially

C _ harmful environmental impacts of contaminated bottom

-• sediments, even in the absence of dredging activity.

INTRODUCTION

The Great Lakes

The Great Lakes are located in the east-central part of North America,

along the border between the United States and Canada (Figure 1). The Great

Lakes system represents an enormous resource. The Great Lakes are the largest

reservoir of fresh water in the Western Hemisphere. They contain almost

23,000 km3 of fresh water. Taken together, the Great Lakes occupy over

240,000 km2 of surface area. Their coastline totals over 15,000 km.

One-fifth of the entire US population and three-fifths of the Canadian

population live in the Great Lakes basin (46 million people). The Great Lakes

are the source of drinking water for 24 million people.

The commercial and sport fisheries total over $160 million and $1 billion

per year, respectively, with about 2 million people participating in these

activities. The sport fishing and recreation industries combined are estimated to add $8 to $12 billion to the Great Lakes economy annually. One-fifth

of all US manufacturing and almost half of Canadian manufacturing is located

in the States and Provinces along the Great Lakes.

The Great Lakes are interstate waters. Eight of the 50 United States are

found along the shores of the Great Lakes--Minnesota, Wisconsin, Illinois,

Indiana, Michigan, Ohio, Pennsylvania, and New York.

87 92-16016
GREENLAND

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C R PANAMA AND TOBAGO

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Figure 1. Location of the Great Lakes

The Great Lakes are also international waters, forming a portion of the

international boundary between the United States and Canada. One-half of the

$150 billion annual trade between the United States and Canada starts and ends

in the Great Lakes States and Provinces.

The International Joint Commission

Background

The United States and Canada realized the importance of the Great Lakes

long ago. In 1909 they signed a treaty, called the Boundary Waters Treaty, to

provide a way to resolve disputes between the two countries over the boundary

88
waters, including the Great Lakes. An organization called the International Joint Commission (IJC) was formed to oversee adherence to the terms of the

treaty.

In 1972, the United States and Canada signed a Water Quality Agreement

specifically for the protection of the water quality of the Great Lakes. The

IJC formed a Water Quality Board to oversee the implementation of the Agreement by the two countries. The Board, in turn, formed a number of Committees

and Subcommittees charged with overseeing the implementation of specific tasks

called for in the Agreement. The Board and its Committees and Subcommittees

are staffed primarily by US and Canadian federal, state, and provincial

government agency personnel.

Areas of Concern

To assist in tracking the attainment of the goals of the Water Quality

Agreement, the IJC has designated a number of locations around the Great Lakes

as "Areas of Concern" (Figure 2). These areas are typically harbors and river

mouths in highly populated areas, where environmental problems have been identified. These geographical areas are designated as Areas of Concern because

one or more beneficial uses of the water (such as for swimming, drinking, and

propagation of a healthy fishery) are impaired. Evidence for this impairment

is found in violations of water quality standards, criteria, or guidelines.

There are 42 Areas of Concern around the Great Lakes.

As a step toward the restoration of beneficial uses in the Areas of Concern, the IJC has requested that the States and Provinces prepare Remedial

Action Plans. The Remedial Action Plans are to lay out specific steps that

need to be taken to fully identify the environmental problems of an area and

to remedy those problems. The Plans are to include a time table for the required actions and are to identify the institutional mechanisms (laws, sources

of funds, responsibilities) that will be used to implement the required

actions.

Contaminated bottom sediments have been identified as a significant

source of the environmental degradation in 38 of the 42 Areas of Concern (Figure 3). Increasingly stringent controls over other sources of pollution, such

as direct discharges from wastewater treatment plants and manufacturing

plants, will continue to reduce the loadings from these sources. This will

scr,.,e to increase the visibility and relative significance of contaminated

bottom sediments as a source of pollution problems. The need to take some

kind of remedial actions on the contaminated sediments will become more

urgent.

The various Areas of Concern exhibit the full range of problems caused by

contaminated bottom sedizMents. Some of the more prominent illustrative examples include the following:

Sheboygan River, Wisconsin - Bottom sediments in the river are contaminated with polychlorinated biphenyls (PCBs). The source of the contamination is past discharges from an aluminum die-casting manufacturer.

Fish caught in the river have the highest concentration of PCBs in the

entire Great Lakes basin.

89
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91
Waukegan Harbor, Illinois - Bottom sediments in a slip of the harbor

are contaminated with PCB concentrations up to 250,000 mg/kg. This is

the highest known concentration of PCBs in sediments in the Great Lakes.

The source of the contamination is past releases from another aluminum

die-casting manufacturer.

Menominee River, Wisconsin and Michigan - Sediments in this river,

which forms the border between Wisconsin and Michigan, are contaminated

with very high concentrations of arsenic as a result of past releases

from a manufacturer of herbicides.

Buffalo River, New York, and Black River, Ohio - Fish caught in these

rivers have been found to exhibit a very high incidence of lip and liver

tumors. The tumors are believed to be caused by the high concentrations

of polycyclic aromatic hydrocarbons (PAHs) found in the river sediments.

Discharges from coking operations at local steel manufacturing plants are

believed to be the primary source of the PAHs.

Keweenaw Waterway, Wisconsin - Bottom sediments in the waterway are

contaminated with very high concentrations of copper from past copper

mining activities. The sediment is so toxic to benthic organisms that

large parts of the bottom are a biological desert, devoid of any life.

St. Clair River and Lake St. Clair, Michigan and Ontario - The

St. Clair River and Lake St. Clair system forms the border between the

State of Michigan and the Province of Ontario. Fish caught in this

waterway are contaminated with mercury and chlorinated styrenes. Sediments contaminated by discharges from chemical plants in Ontario near the

head of the St. Clair River are the most likely cause of the fish

contamination.

Port Hope Harbor, Ontario - Bottom sediments in this harbor are contaminated with uranium, radium, thorium, radioactive lead, heavy metals,

and PCBs. The contamination is the result of local radium and uranium

refining operations prior to 1948.

Toronto Harbor, Ontario - Sediments in parts of the harbor are highly

contaminated with a variety of metals and synthetic organics. Benthic

biota have bioaccumulated mercury, zinc, copper, chlorinated organic

chemicals, including PCBs, and pesticides.

Thunder Bay Harbor, Ontario - A wood preserving operation in the

north end of the harbor has contaminated the harbor sediments with a wide

variety of toxic substances, including dioxins, furans, creosote,

pentachlorophenol, and PAHs.

CONTAMINATED SEDIMENT ACTIVITIES

Past Actions Regarding

Contaminated Sediments

The United States and Canada have given increasing recognition to the

problems posed by contaminated sediments, and they have taken specific steps

through the IJC to deal with them.

92
In the past, contaminated sediments in the Great Lakes basin have only

been addressed in the context of dredging and disposal projects. When the

sediments needed to be dredged, decisions had to be made about where to dispose of them. In particular, it was necessary to determine whether the

dredged sediments were sufficiently free from contamination so that they could

be disposed of in the open waters of the Great Lakes. The United States and

Canada developed individual dredging and disposal guidelines for this purpose.

The guidelines were empirically derived from a data base of bulk concentrations of chemicals in the harbors.

The Water Quality Agreement recognized the need for compatible guidelines

between the two countries for evaluating dredging projects in the Great Lakes.

The Agreement called for the establishment of a Dredging Subcommittee to develop these guidelines, in addition to other charges they were given regarding

reporting on dredging and disposal activities in the Great Lakes. In 1982,

the Dredging Subcommittee published their recommended guidelines for the evaluation of disposal options for dredging projects (IJC 1982). These guidelines

were based upon the principle that disposal of the dredged sediments should

not degrade the benthic quality of the main bodies of the Lakes. However,

they were still only dredging guidelines and did not consider the situations

in which the contaminated sediments were creating a problem by their mere

presence in the waterway.

A Task Force of the Science Advisory Board of the IJC held an international conference on contaminated sediments in Aberystwyth, Wales, in August

1984. This was the first IJC activity that dealt specifically with the contaminated sediment issue outside the dredging context. A conference proceedings was published (Thomas et al. 1987).

With the subsequent emphasis on Remedial Action Plans for the Areas of

Concern, the IJC sponsored a workshop on monitoring that was held in

Burlington, Ontario, in October 1985. A report entitled "Guidance on Characterization of Toxic Substances Problems in Areas of Concern in the Great Lakes

Basin" was produced based upon the results of that workshop (IJC 1987). This

document addressed the entire range of pollution issues, including monitoring

of point and nonpoint sources, as well as monitoring of sediment, water, and

biological quality.

In 1986, as a result of the growing recognition of contaminated sediments

as an issue to be addressed in a broader context, beyond that of navigational

dredging, the Water Quality Board restructured the Dredging Subcommittee as

the Sediment Subcommittee. The Sediment Subcommittee was given a broad Terms

of Reference to address contaminated sediment issues of all kinds.

Guidance on Sediment Assessment

and Remedial Option Selection

The IJC felt an urgent need to provide those responsible for preparing

the Remedial Action Plans for Areas of Concern with guidance on how to address

contaminated sediment problems. Therefore, it charged the Sediment Subcommittee with the preparation of a draft guidance document for presentation at a

meeting of Remedial Action Plan Coordinators to be held in Toledo, Ohio, on

November 19, 1987. The purpose of the guidance document is to assist the

93
Remedial Action Plan authors in designing the proper studies to assess contaminated sediment problems, and to provide guidance on how to select from

among the possible actions that could be taken to remedy the problem.

The guidance document will recommend a set of tools to be used in problem

assessment, including:

a. Physical tests to characterize the distribution, type, and quantities

of sediments.

b. Chemical tests to determine the nature and degree of chemical

contamination.

c. Laboratory and field test protocols to assess the biological impacts

of the contaminated sediments, including tests of:

(1) The acute and chronic toxicity of the sediments.

(2) The bioaccumulation of chemicals by benthic and pelagic

organisms.

(3) The impairment of reproductive processes.

(4) The induction of mutagenic or carcinogenic responses in biota.

The guidance document will also discuss the selection of remedial action

alternatives. Among those that will be discussed are the following:

a. Removing the contaminated sediments from the water body.

b. Covering the contaminated sediments to isolate the contaminants from

the water column.

c. Solidifying the sediments to reduce the mobility of the contamirlants.

d. Decontaminating the sediments using some process to extract or

separate the contaminants from the sediments.

e. Relocating navigation so that dredging and navigation do not disturb

the contaminated sediments.

f. Taking no action and letting natural cleansing processes reduce the

severity of the problem with time.

In conjunction with the remedial action options, the guidance document

will discuss a number of disposal alternatives for contaminated sediments,

Ahould removal be needed as part of the process. Among the disposal options

L.,at will be considered are:

a. In-water unconfined disposal, which is the traditional type of

disposal.

b. In-water confined disposal, which is disposal inside a diked area of

the lake, often adjacent to the harbor breakwater structures.

94
c. Upland disposal, which is disposal in a bermed facility (possibly

lined with clay or plastic) above the water table.

d. Deep-hole in-water disposal, which consists of disposing in an existing or excavated depression in the lake bottom to prevent the transport of the deposited sediments outside the disposal area.

e. Capping with clean sediment to isolate the contaminants from the

overlying water column and to prevent the erosion and transport of

the capped contaminated material.

f. Agricultural land application similar to the process used to dispose

of sewage sludge.

g. Beach nourishment where lightly contaminated, coarse-grained material

is used to rebuild an eroded beach.

This guidance document is only the first step by the Sediment Subcommittee in providing guidance on contaminated sediment issues. Some of the

assessment techniques discussed, as well as remedial options identified, will

become the focus of future efforts by the Sediment Subcommittee.

The Sediment Subcommittee will be hosting workshops to further refine the

assessment criteria. The Subcommittee will conduct technology transfer workshops to identify and clarify the utility of emerging remedial options.

Finally, the Subcommittee will promote the field-testing of the recommended

assessment methods and candidate technologies.

Through the efforts of the Sediment Subcommittee of the IJC, the United

States and Canada are coordinating their attack on the contaminated sediment

problem in the Great Lakes.

REFERENCES

International Joint Commission. 1982 (Jan). "Guidelines and Register for the

Evaluation of Great Lakes Dredging Projects, Report of the Dredging Subcommittee of the Water Quality Board," Windsor, Ontario.

_ 1987 (Mar). "Guidance on Characterization of Toxic Substances

Problems in Areas of Concern in the Great Lakes Basin, Report from the Surveillance Work Group," Windsor, Ontario.

Thomas, R., Evans, R., Hamilton, A., Munawar, M., Reynoldson, T., and

Sadar, H., eds. 1987. "Ecological Effects of In Situ Sediment Contaminants,"

Hydrobiologia, Vol 149, pp 1-4.

95
REMOVAL AND DISPOSAL OF ACCUMULATED ORGANIC SLUDGE

IN THE OSAKA PORT AND HARBOR AREA

•- M. Konae

. •Deputy Manager, Port Development Department

Port and Harbor Bureau, City of Osaka 3-1-3-1107

- Sagisu, Fukushima-ku, Osaka 553, Japan

-• ABSTRACT

Since 1974, the Osaka Port and Harbor Bureau has

removed organic sludge totaling more than 3 million m

and disposed of it at the North Port disposal area.

As this is a sea reclamation disposal area, water

quality control and discharged water quality improvement are important in terms of environmental

preservation.

The present survey has clarified the following

points:

a. Water quality at a disposal area is affected

IC by the seawater contained in the dredged

0 • soil, meteorological conditions (water temperature, precipitation, sunlight, etc.), and

proliferation of phytoplankton.

b. When a disposal area occupies a wide area,

I• - the chemical oxygen demand (COD) value, which

the typical SJisindex of pollution, remains

low while the water is deep, but will rise

rapidly as the water depth becomes shallower,

due to shortened residence time of discharged

water and proliferation of phytoplankton.

c. Remarkable improvement in discharged water

quality can be achieved by installing

pollution-prevention membranes directly in

front of the water discharge outlets.

INTRODUCTION

Osaka Port, situated at the center of Osaka Bay, enjoys good meteorological and sea weather conditions and has developed as a leading Japanese international trade harbor serving a wide hinterland. At the core of this expansive hinterland is the city of Osaka, which has a population of approximately

1.5 million and is one of the two biggest centers of Japanese industry and

economy.

96
Large quantities of water-polluting substances are discharged from this

area and carried via rivers to the port and harbor area, deteriorating the

bottom sediment quality. Therefore, since 1974, the Port and Harbor Bureau of

Osaka has been dredging sludge from rivers and estuaries in polluted areas of

the bay as a part of the port and harbor pollution control project.

This report represents results of studies and analyses of organic sludge

removal and disposal, with focus on water quality control at the disposal

areas in respect to the bottom sediment quality improvement project of Osaka

Port.

PROJECT FOR IMPROVEMENT OF BOTTOM SEDIMENT QUALITY, OSAKA PORT

A number of rivers flow into Osaka Port (Figure 1) and the water of these

rivers is becoming more and more contaminated, both organically and artificially, from rapid industrial development and urbanization in the basin areas

and from sludge accumulated in the Aji, Shirinashi, and Kizu Rivers and their

estuaries, which are particularly contaminated by organic substances.

I TYodo live

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North Port

Southern are 7Shrnash River

e of Ncrth Pt /

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struct Lon) Tl rFr

Boundary~Sa vi ofOskai 

Osaka Port, as outlined in Table 1, are based on the Osaka area pollution

prevention plan and are as follows:

97
a. To improve water quality by preventing dissolved oxygen (DO)

consumption and the generation of foul odors and noxious gases due to

the stirring of deposited organic sludge by navigating ships.

b. To improve water conditions to a life-sustaining level by removing

sulfides and oily substances contained in the bottom sediment.

TABLE 1. POLLUTION PREVENTION PROJECT, OSAKA PORT

Project Element Description

Source of pollution Drainage from factories and households

Subject sections Kizu, Shirinashi, and Aji Rivers and their estuaries

in Osaka Port

Period 1974-1995

Contamination Organic sludge

condition COD,* 27-54 mg/g

Oil substances, 23-38 mg/g

Sulfides, 5-11 mg/g

Ignition loss, 15-22 percent

Removal standard Removal of organic sludge of more than 15 percent

ignition loss satisfies standard requirements for

COD, oily substances, and sulfides, etc.

Volume to be handled Handled - 1974-1986 3,174,000 m3

Planned - 1987-1995 1,720,000 m3

Dredging and disposal Dredging by the Pneuma pump dredge system,

450 m /hr (pure water)

Dredging by closed-type grab dredge, 4 m3 /bucket

Transport by box barge, 350-450 m3

Sludge unloading by disposal ship, 160 m3 /hr

(pure water)

Discharge filling by discharge pipe

Disposal areas North Port disposal area

North region second and third areas 1,622,000 m2

South region second and third areas 2,148,000 m2

Measures to be taken Improvement of sewerage in Osaka Prefecture, as well

for discharge source as Osaka: 100% target, to be achieved in 1990

of polluting

substances

Other projects Rivers upstream of those flowing into the bay area

and running through Osaka City have been cleared

of sludge under the river purification project

determined by permanganate SCOD oxidation.

98
DREDGING OF ORGANIC SLUDGE

Organic sludge removal has been accomplished using a Pneuma pump dredge

and closed-type grab dredge. Since dredged earth and sand contain a high

proportion of mud and since this system causes less pollution and less disturbance of the existing earth bed and resultant muddy water, the dredging work

has been carried out mainly by Pneuma pump dredge, with additional dredging by

the closed-type grab dredge for areas of shallower water depth and small-scale

dredging for areas of harder earth. Figure 2 is a flowchart of organic sludge

removal.

Closed type grab dredge Disposal ship

•Transport barge Dischar~e pipe

Disposal area

w Diffusion

Pneuma pump dredge protector

(Dredging) (Transportation) (Unloading and discharging)

Figure 2. Organic sludge removal flowchart

The yearly volumes of dredged organic sludge are shown in Table 2.

Table 3 summarizes the surveys conducted before, during, and after dredging

activities.

NORTH PORT DISPOSAL AREA

Disposal Area Description

The North Port disposal area is 3ituated at the western end of Osaka Bay

and is composed of two sea reclamation areas (northern and southern), each

divided into three zones (Figure 3).

99 Konae - 4
TABLE 2. YEARLY VOLUME OF ORGANIC SLUDGE

Fiscal Year

1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 Total

Dredged volume, 110 244 189 285 290 256 256 251 287 279 252 275 200 3,174

1,000 m3

TABLE 3. SURVEY WORK ASSOCIATED WITH DREDGING OF ORGANIC SLUDGE

Activity Description Purpose

Before dredging

Surveying of Mud sampling down to clay Mainly for use as basic data

bottom sedi- layer by thin wall-type to determine removal depth

ment quality bottom sampler

Sampling of surface mud by To determine disposal method

Ekman barge-type sampler acceptability according to

the acceptance standard

During dredging

Sounding Depth measurement by To determine earth volume to

echo-sounder be dredged

Soil Soil sample taken into a To confirm earth volume

exploration barge for measurement of deposited in disposal area

water content, unit volume, and weight

Environmental Water quality analysis sur- To monitor environmental pamonitoring veys in dredging areas and rameters (COD, SS, DO,

areas downstream etc.) to determine water

pollution in compliance

with Article 15 of the

Water Pollution Prevention

Act

After dredging

Sounding Depth measurement by To confirm dredged depth and

echo-sounder calculate dredged earth

volume

Bottom soil Sampling of surface layer To confirm improved bottom

exploration soil by Ekman barge-type soil quality by dredging

sampler

100
Fist

Soo x ~A / too Third -Sea

Zonew 30Zone 

Partitionon30 a

dak 0a~co dike (1 Pait 0

• o•/ o later quality eurveying pant

Scnd Zone 5 / A Botto aediment quality uurveying

Seon dike (2) Norher

Figure 3. Layout of North Port disposal area

The northern area began accepting waste in 1974, while the southen area

is still under construction; however, this area has been partially accepting

waste since 1985 and dredged earth and sand since the beginning of 1987.

Features of the North Port disposal area are summarized in Tale 4.

TABLE 4. NORTH PORT DISPOSAL AREA

Item Northern Area Southern Area

Area, ha 209 288

Capacity, mn3 25,000,000 50,000,000

Construction period 1972-1977 1977-1990

Acceptance period 1974-1987 1985-1995

Acceptance conditions, o 3 28,000,000 (112%) 460,000 (First area)

101

dik (3) poin
Disposal Records

The first area of the North Port disposal area accepts not only organic

sludge, but also ordinary waste such as refuse, sludge from city water and

sewerage systems, and industrial waste. Organic sludge, other dredged earth

and sand, as well as excavated earth from construction sites are placed in the

second and third areas. Acceptance records for 1975-1986 are presented in

Figure 4.

20

0 1975 1976 1977 1976 1979 1%80 1981 1982 1983 1964 1985 1986 Year

Remarks: x First zone - ordinary waste, sludge from city

water and sewerage systems, industrial waste

ASecond and third zones - organic sludge from

the bay areas

0 Second and third zones - other dredged earth,

and sand and earth from construction sites

Figure 4. Acceptance records at the North Port disposal area

Seawalls and Partition Dikes

Figures 5-9 indicate typical seawalls and partition dikes. As shown in

Figure 5, seawall A comprises a composite breakwater fronted with wave dissipation blocks; for its foundation, the sand drain method was adopted for subsoil improvement.

As shown in Figure 6, seawall C faces a ship navigation route. To avoid

interfering with this route, to shorten the construction period, to decrease

the construction cost, and to enhance safety in construction, the driven steel

pipe pile system was used. The subsoil was also improved by the sand compaction pile method.

Since seawall G is exposed to rough waves from the open sea in winter,

the wave passivation caisson structure was adopted for this seawall; subsoil

was improved by the sand compaction pile method.

102

a
10.00 30.00 /.2.00 16.00 7.00

20.00 12.0

ICellular block3- 50 ,.00 sr

) 1 Wlave diselp 1s-iHWL D .g pgtsction stone DL +2_'00n ou

I 0 :I2.i00 Fe ndacion rubb-.0 :8L/J01:

1:6 2.00______8___________0___0

i Sand piles (squarely positioned)

*'00 c.C.c. 2.00

DL- 22.00 Unit: a

L 30.00 I40.00

OL -28.00 '--31.00

Alluvial sandy stratum

DL -3S.00 '- -36. 00

Sandy gravel stratum

Figure 5. Cross section of seawall A

12.0 158.00

HWLuvl sandy +1. Solson

0.00.0 36' Soil__sound

Sandy pr ote cto 6 -40D-ljSn on

stratuh 203 20.00 DL 

Ma log 4.00 So 300000

Figre . Cosos setk f evl

103ct
33.00

D 5+1.70 L÷6.80

,_ _. _.L+_1.70________ DL+ 1.00 ater level

,: ? Dis p a¢osen t sand giis and sa

7 4ig rossac-n.n Saud pile (squarely positioned)

Sand coaction PUG c5 2 .BL 24.00 R atto of displacemntn 502

___ __ ___ ___ DL - 30. 00

All Ial sandy stra am DL- 36.00....

-San -'ravel stnat 6

Figure 7. Cross section of seawall G

3S.00 t%2,00 MI

TGrod $36 .00 I .00

HL 3003300 3N10 x DL .0

Sand piles $400 Sand piles

c.t.c. 2.00 $400 Sand plies #4.00 c.t.c. 3.30

c.t.c. 2.00

Steel sheet piles U

length 25.00

SD.- 20.00

.50.000 i

ALluv•al sandy stratum DL- 35.00

Sandy gravel stratcu

Figure 8. Cross section of partition dike 1

104
4I 0.00

20.00 20.00

15.00

DL +9.00 DL 8.5 DL+ 10.50

__÷__ _________/ 00 _ n___+_A._nod 350 150 1" x 19 length *_DL÷6.00 9.60

D1 0---.00-- =Io• %__ .1111__d__-__._ _---_- DL +o 2 Tie rod 0 c...c. 3.20

-Soil sound St Rclamation'ill

Sand mound -6 ' 6 

DL- .00 6DL- A time of-first sand mound DL- 3._

I DL -7.20 Sand piles (squireld sac m n pt Sand piles (squarely positioned) ad.t.. 2.00 (positioned)

c.t.c. 3.50 D C.t.c. 3.50

______________ jDL- 20.00____ ___________1

DL- 27.00_- 28.00 _

145.00 9 45.00

D0 9.00 Alluvial sandy stratum DL -35.00 •. - 36.00

Sandy gravel stratum

Figure 9. Cross section of partition dike 2

Since the North Port disposal area is used to bury waste of different

kinds, such as organic sludge and ordinary waste for disposal, a partition

dike of double steel sheet piles was installed to isolate the area. Further,

since the partition dike can handle traffic, its installation serves to ease

reclamation work, maintenance, and control. In addition, steel sheet piles

longer than those used for partition dike 2 are used for partition dikes 1

and 3 to secure watertightness. Partition dike 3 has the same structure as

partition dike 2.

ORGANIC SLUDGE DISPOSAL

Organic sludge pumped from barges through the ship is then discharged

through the sand discharge pipe into the disposal area. Diffusion protectors

are installed near the sand discharge pipe outlet to expedite sedimentation of

sludge and prevent the spread of muddy water oil contamination (see Figure 2).

Since the North Port disposal area accepts various other kinds of waste

in addition to organic sludge and since overall water quality control is important, acceptance ranges for other kinds of waste have been developed and

are discussed below.

Earth and Sand Dredging

These materials are carried by barges to the second and third zones of

the disposal area and pumped via the following two methods:

a. Direct pumping. Dredged earth and sand are pumped from the barge

through the ship; then, they are pumped to the disposal area via the

sand discharge pipe.

105
b. Pumping after temporary storage at the pocket. Dredged earth and

sand are carried by the bottom-hopper barge to a sea bottom pocket to

be stored there temporarily, and are then pumped to the disposal area

via the sand discharge pipe. However, in recent years, method a has

been used primarily for pumping to the discharge area.

In both methods a and b, diffusion protectors are installed in front of

the sand discharge pipe outlets to expedite sludge sedimentation and prevent

the spread of muddy water and oil contamination.

Ordinary Waste

This type of waste is carried by barges from the shipping base and landed

by crane; then, it is carried by dumptrucks to the disposal area, where it is

scattered by bulldozers.

Further, over every 3 m of waste fill, an earth covering 0.5 m thick is

emplaced to prevent airborne waste, odor, and the generation of noxious

insects.

Sludge from city water and sewerage systems, as well as residual earth

from construction sites, is also carried by barges from their shipping base

and disposed of by reclamation in a manner similar to that for ordinary waste.

Before disposal by reclamation, all wastes are checked for noxious substances, in accordance with the acceptance standards.

Environmental Preservation Measures

Environmental monitoring activities, including surveys of water quality

and bottom sediment quality, in addition to the following preservation measures, are carried out in the disposal and peripheral sea areas.

a. Wastewater discharged in the first zone is improved in quality by

aeration treatment in the oxidation basin.

b. To remove gas generated by the waste, gas extractor equipment is

installed in the first zone.

c. To prevent airborne refuse, preventive fencing is installed around

the first zone.

Water quality is surveyed once a week in the disposal area and once a

month in the peripheral sea area (at points shown in Figure 3) for pH, DO,

COD, etc. Bottom sediment quality is surveyed once a year in the peripheral

sea area for pH, DO, ignition loss, etc.

WATER QUALITY CONTROL AT DISPOSAL AREA

The discussion that follows focuses on the northern area, since the

southern area is not yet accepting waste regularly.

Wastewater flow in the disposal area is as follows: the wastewater in

the first zone is aerated in the oxidation basin and discharged to the second

106
zone; from the second zone, wastewater is discharged to the third zone.

Wastewater is released to the open sea from the second discharge outlet (Figure 10). (Use of the first discharge outlet has been suspended since 1983.)

Second discharge outlet

Pollution preventive First discharge mt3embrane

from fi~rst the zntohescndae p . o82(vrg .) O 0t

SI Third

one zone

Oxidation 

basin Second zone

Figure S0. Wastewater flow in northern area

Water quality conditions at the oxidation basin just before discharge

from the first zone to the second are pH 7.7 to 8.2 (average 8.0), COD 60 to

110 mg/t (average 84 mg/t), and DO 1.5 to 9.0 mg/i (average 7.3 mg/1). However, sincarhe volume of this discharge is not great and since the organic

sludge dealt with in thin s flow t disposed of in the second and third zones,

the discussion herein presents the results of analyses of wastewater from the

second and third zones.

Soll and Water Levels

at Second and Third Zones

The second and third zones, which comprise 1.622 million m2 in reclaimed

land area, are used as stabilization ponds for physical and biological purification during a continuous flow time of from to c00 200 days, to purify sludge

pumped into these zones and to repurify water discharged from the first zone.

Presently, reclamation activity in tae te pohird zonest is (salmost

complete. 2, Figure indicates the yearly change in soil and water levels in

the reclamation land.

Water Quality Surveys

Water quality surveys (once a month) have been conducted for 4 years

(since 1983) to analyze water quality in the disposal area and at the discharge outlet based on survey results taken at three points, Stations (St.) 1,

2, and 3 (shown in Figure 10).

Water Temperature

As indicated in Figure 12, annual seasonal change patterns of individual

sampling points do vary greatly, which is also true of them collectively. It

107
+8 water level••..=, •

. k/culed /ca 0.01 2 led

35

1979 1980 1981 1982 1983 1984 1985 1986 1987

30 •

Iso

* ,I i I .1

1979 1980 1981 1982 1963 1984o 1905 1986 1987

Figure 11. Changes in soil and water levels

35,

25-' . d 1

for' " SiO 

4 If

2.15- '

I. I -ffi / be 10 .l I I

5 8 1 2 .5 8 11 2 8 2 .5 .5 8 1 2

(1983) (1984) (1985) (1986) Month

Figure 12. Monthly changes in water temperature

should be noted that no measurements were taken at St. I in 1986 because of

reclamation work. Also, the reader should note that seasons of the year are

defined as follows: spring (March, April, and May), summer (June, July, and

August), fall (September, October, and November), and winter (December,

January, and February).

pH

As shown in Figure 13, the so-called cyclic changes, i.e., the increases

of pH in spring and fall and decreases in summer and winter, are notable.

108
10 x St. 1

o St. 2

* St. 3

A A9

~~A

8 V6

5 8 11 2S' 1 8' 11' 2' 5' 8' 11 '2'

(1983) (1984) (1985) (1986) Month

Figure 13. Monthly changes in pH

Possible factors involved in the increase are the photosynthesis of

plants and deposited earth and sand; however, since the cyclic changes in pH

level coincide with extraordinary proliferations of phytoplankton, this is

believed to be the cause.

Suspended Solids (SS)

As indicated in Figure 14, the large fluctuations seen in 1983 and 1984

were noL seen in 1986; peaks due to proliferation of phytoplankton were seen

in the spring and fall seasons of that year, though at no time did SS exceed

40 mg/t.

Probable factors involved in SS increase are the stirring of the bottom

sludge of the deposited soil and phytoplankton proliferation.

The low increase at St. 3, especially in spring and fall, is considered

to be due to the pollution-prevention membranes installed in 1985.

Dissolved Oxygen (DO)

As shown in Figure 15, the level of DO followed cyclic changes due to

water temperature fluctuation (high in winter, low in summer) and temperature

increase, due also to the extraordinary proliferation of phytoplankton in

1986.

Chemical Oxygen Demand (COD)

As indicated in Figure 16, COD tends to increase in spring and fall when

phytoplankton proliferate, a tendency that was conspicuous in 1984 and 1986.

However, measurements at St. 3 were less than 15 mg/t for most months of the

year, being as low as 20 mg/i even in February, when the phytoplankton

proliferated. This was considered to be the effect of the pollutionprevention membranes.

109
80 '97 x St. 1

o St. 2

70 J 0 St. 3

60- /

50 73 iIII I I I , 11

40-

t 1o II I I II

30, I i .. 1 I ,

20. I I

"10 I 1 .

5 8 11 2 5 8 11 2 5 8 11 2 5 8 11 2

(1983) (1984) (1985) (1986) Month

Figure 14. Monthly changes in SS

30- T x St. I

So St. 2

9 St. 3

25 S I I

2% i 1b 

/ m

.15-

11 2 5 8 11 2 5 8 11 2 5• 8 11 2

(1983) (1984) (1985) (1986) Month

Figure 15. Monthly changes in DO

On the other hand, as shown in Figure 17, the soluble COD level tends to

rise every year beginning in spring, when the phytoplankton generc -y starts

to proliferate, and to decrease in the fall. The level of soluble COD has

been below 20 mg/1 almost continually for the past 4 years, with the fluctuation not so great as that of COD.

110

• - .,m~m~nm,.,,mmmn mmmm lm mllllmlll I IW I
50I x St. 1

o St. 2

I i ~e St. 3

40 ,

I ' ', ,.' -~30 'i .II

U " 20 V ''JI 1 j ~ Ii ~ J

10

5 8 1Y 2 5 B 11 2 5 '8 8 2 5 8 '1 2

(1983) (1984) (1985) (1986) Month

Figure 16. Monthly changes in COD

50 x St. I

* St. 2

* St. 3

40

"V 30

oP

.20-2 A

I ' A %

0-

5 8 I1 2 5 8 "1 2 5 8 11 2 5 8 11 2 (1953) (1984) -' (1985) (1986) Month

Figure 17. Monthly changes in soluble COD

Kjeldahl Nitrogen

As indicated in Figure 18, this tends to gradually decrease from spring

to summer and to increase gradually from fall. However, in 1986 the peak

appeared about 2 months earlier than in other years, which is thought to have

been due to lessening of water depth and continuous flow time as construction

work progressed.

Total Phosphorus (T-P)

As shown in Figure 19, 1986 was also a year in which remarkable cyclic

changes occurred in T-P level, gradually increasing from spring to summer and

i11
40 x St. I

* St. 2

35- e st. 3 '

S30- 00oii| / . i

"25-

10 1,

5 81 2 81l' I 2' 

"~ ~ "t "' ' I\Ijj

SI., ,

5 8"11 2 5 8 11"2"5 8........5 8"'12"

(1983) (1984) (1985) (1986) Monch

Figure 18. Monthly changes in Kjeldahl nitrogen

1.4 x St. 1

* St. 2

1.2' Al0St. .0 3

0.8. I % 

1.0.6 %Ij 1 1 It jiI

Y!, ,,,

I "I IJ oil I/

0.2 if

a II;

5 8 11 2 5 8 v1 11 2 5 8 11 2 5 8 2

(1983) (1984) (1985) (1986) Month

Figure 19. Monthly changes in T-P

112
again decreasing from fall. Levels of T-P have dwindled year by year such

that, even in September, the month of the 1986 peak, the value did not exceed

1 mg/k.

Volume of Pigment

Volume of pigment is an index of phytoplankton proliferation that, as

indicated in Figure 20, tends to peak in spring and fall. On the other hand,

the pigment volume measured at St. 3 was not very high during the peak seasons

of sprint and fall. Even in February, when the maximum value was seen, it was

636 mg/mi, indicating a remarkable difference from St. 2.

4,000 iix X St. 1 I o St. 2

_ 3,500 0 St. 3

r 3,000

r 2,500I

2,000 - I

"".? it

1,500-

o 1 ,000o f i•

If :1 ' t' I I I I

500' I 'IA,. j*,

91 %" ,••Y V..!'V\_• 

0 Id Y' V R.~ .~

5 8 11 2 5 8 11 2 5 8 11 2 5 8 11 2

(1983) (1984) (1985) (1986) Month

Figure 20. Monthly changes in volume of pigment

Salt Content

As indicated in Figure 21, salt content distinctly increased from fall to

winter and decreased from spring to summer.

This cyclic change is considered to be due to the combined effects of

seawater contained in dredged soil and meteorological conditions (precipitation volume, sunlight, etc.). The value rise through 1985 and 1986 is considered to be due to diminishing water depth.

Water Discharged to Sea

Target Water Quality

To adhere to the applicable water discharge standards as set forth by the

relevant laws and regulations, to observe the purport of the Inland Sea

113
34

32-

~30- .11 011

0I -• It1eft

26-• .,,,

U 24 - ib 5

20 . b. I..

v' I

(1983) (1984) ( 1985) (1986)

Figure 21. Monthly changes in salt content

Environmental Preservation Special Measure Act, and to decrease the effects on

the marine environment, water quality has been controlled by determining control targets for COD and SS (Table 5), which are typical pollution indices.

TABLE 5. TARGET VALUES FOR WATER DISCHARGED FROM

NORTH PORT DISPOSAL AREA

Standards for Discharge

Water Set Forth in Article 1, Order of the

Parameter Prime Minister's Office Target Value

COD, mg/1 160, 120" 50

SS, mg/2 200, 1500 70

* Daily average value.

Water Quality Control by COD

Monthly changes in COD since the beginning of reclamation are shown in Figure 22; the value in 1979, when the water at the reclamation site was deep, was less than 20 mg/C , reaching a high point of 50 mg/t in 1984, when the

water depth had become shallow.

114

Art icle 1,Odro h
40 Remarks: - COD in discharging water

--- COD load at the disposal area

30. .

0

S20-

0 0

U

-15 c

10 ' 10 At J[ l , t. I IAI [ 5/ Vj II 

A

VIP,.t.A

. •~ i SI I -

0

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987

Apr. (Year)

Figure 22. Monthly changes of discharging water in COD

For this reason, as indicated in Figure 10, pollution-prevention membranes were installed immediately in front of the water discharge outlets in

1985; the COD value has thus far been kept to a low level of 20 mg/i on

average.

As stated above, controlling the quality of discharged water was somewhat

easier when the water at the reclamation site was deeper; however, it was made

more difficult due to factors such as continuous flow time as the water became

shallower, requiring special water treatments such as the pollution-prevention

membrane.

CONCLUSIONS

When a disposal area is a sea reclamation disposal area, water quality

control in the disposal area and improvement in discharged water quality are

important themes.

The present survey clarified the following points and yielded significant

data for future water quality control in the disposal area:

a. Water quality in a disposal area is affected by seawater contained in

dredged soil, meteorological conditions (water temperature, precipitation, sunlight, etc.), and proliferation of phytoplankton, of which

the latter exerts the greatest effect upon water quality.

115
b. The water quality indices largely affected by phytoplankton proliferation are pH, SS, and COD, which exhibit remarkable cyclic

changes through the year with higher values in spring and fall and

lower values in summer and winter.

c. Comparison of the sampling stations in the disposal area showed that

water quality in the second (St. 1) and third (St. 2) zones and at

the second water discharge outlet (St. 3) exhibited similar changes

for each survey item, with no remarkable difference among these

points.

d. When a disposal area occupies a wide area, the COD value, a typical

index of pollution, is lower while the water is deeper, but deteriorates rapidly as the water becomes shallower, due to the shortened

continuous flow time of discharge water and the lessened phytoplankton proliferation.

e. Although various kinds of water treatment are conceivable in coping

with water quality deterioration in a disposal area, in the case of

the city of Osaka, remarkable improvement in discharged water quality

was achieved by installing pollution-prevention membranes immediately

in front of the water discharge outlets.

Many points remained unresolved by this analysis in the disposal area;

these points must be clarified by future surveys and research. It is hoped

that our observations of the removal and disposal of accumulated organic

sludge in the port and harbor area, with emphasis on water quality control at

the disposal area, contribute in some way to the environmental improvement of

port and harbor areas in Japan and the United States.

116
,.:IMPACT ASSESSMENT OF IN-PLACE CONTAMINATED SEDIMENTS

"ON WATER QUALITY: AN APPROACH

T. L. Hart, D. Gunnison, and J. Brannon

Environmental Laboratory

,y) US Army Engineer Waterways Experiment Station

Vicksburg, Mississippi 39181-0631

G ABSTRACT

_____ In the past, environmental assessments of Corps

of Engineers (CE) Civil Works water resource projects

I that involve dredging of contaminated sediments have

addressed only the consequences of dredged material

disposal. The environmental benefits that may be

incurred from the removal of in-place contaminated

sediments have not been considered. This deficiency

in evaluating the environmental consequence of sediment removal has been due to the lack of a logical

delineated approach to quantifying the impacts of contaminated sediments on water quality as well as the

reluctance of regulatory agencies to consider contaminated sediment removal as a benefit. This paper presents a conceptual approach developed for the

operations and maintenance Federal navigation projects

for assessing the environmental consequences of inplace contaminated sediments. The approach, along

with potential benefits, is delineated. Further, the

concept has application to other water resource projects that involve contaminated sediments. The basic

concept has recently been applied to a Civil Works

project in the Grand Calumet River and Indiana Harbor

Canal system, Indiana, USA. Results of this study are

presented to show the steps necessary for implementing

the concept and to illustrate potential uses of the

data, along with restrictions on implementation and

use.

INTRODUCTION

The CE, as one of the Nation's major construction agencies, has responsibility for the construction and maintenance of over 25,000 miles (40,000 km)

of Federal channels, over 100 commercial harbors, and 400 small boat harbors.

The CE annually removes 250 to 300 million cu yd (190 to 230 million cu m) of

dredged material. A small, although significant portion of the sediments

dredged is contaminated and requires special handling and disposal. These

sediments may contain a multitude of toxic materials, including polycyclic

aromatic hydrocarbons, polychlorinated biphenyls (PCBs), heavy metals,

117 92-16017
pesticides, and by-products of industry. These contaminated sediments are

normally associated with the Nation's urban industrial waterways, where

Federal channels act as catchment basins for sediments.

In the construction and maintenance of Federal channels, the CE must comply with Federal and state environmental legislation and evaluate the environmental consequences of dredging and disposing of these sediments. In

evaluating the environmental impacts of the dredging and disposal of contaminated sediments, the major emphasis has been on the short-term impacts on

water quality from dredging and the short- and long-term impacts on the environment from disposal. Minimum attention has been given to either the environmental effects of contaminated sediments in Federal channels on the water

body or the environmental benefits that may accrue from sediment removal.

Strong public opinion against the removal and disposal of contaminated

sediments has been and is still often expressed. Objections are based on the

belief that the environmental consequences of sediment removal and subsequent

disposal exceed the social and economic benefits gained from the project.

Although polluted sediments are often located in highly industrialized and urban areas, they are neither stationary nor inert. These sediments continue to

exert an influence on the water quality of the waterway through oxygen demand

and release of nutrients and toxic substances, as well as supporting only a

limited pollutant-tolerant community of poor species diversity. Further, the

resuspension of these sediments by natural and man-induced causes will not

only affect the overlying water column, but may also impact the water quality

for miles outside the immediate area of concern.

Polluted sediments are not confined to Federal channels and major harbors

in our urban and industrial areas. Spills from chemical and petroleum barges

and small chemical and petroleum terminals have resulted in localized pockets

of contaminated sediments in areas far removed from our major metropolitan

areas. Runoff from agricultural areas and timberlands also introduces pesticides and nutrients to the Nation's waters, often resulting in river, reservoir, and estuary sediments becoming contaminated. Point discharge from

feedlots, chemical companies, and city sewage treatment plants has also been a

source of nutrients and contaminants that have affected sediments. Many of

these polluted sediments are located within Federal water resource projects

built and maintained by the CE. The effects of these sediments on the continued operation and maintenance of these projects, as well as proposed modifications to current use, can be significantly affected by the presence of

contaminated sediments.

For a more complete assessment of cost versus benefits associated with

maintaining specific water resource projects, the impacts of in-place sediments on the environment must be considered. If the CE can determine and

quantify the impacts, the "true" cost of the project's social, economic, and

environmental attributes can be determined.

LEGAL CONSIDERATIONS

One major portion of the CE planning effort in maintaining Federal channels is compliance with Federal and state environmental legislation and implementation of agency regulations. Often for Federal navigation projects, the

major concern is with the requirements of Sections 401 and 404 of the Clean

118
Water Act of 1977 (CWA) and Sections 102 and 103 of the Marine Protection,

Research and Sanctuaries Act of 1972 (MPRSA). Each of these sections deals

with the disposal of dredged material and associated potential environmental

impacts. Under Section 404, an evaluation of the effects of dredged material

discharge into navigable waters of the United States is made based on the

US Environmental Protection Agency 404(b)1 guidelines. For certain situations, a water quality certification (Section 401) from the affected state is

required. This certification ensures that the project meets state water quality requirements. For those projects where disposal of dredged material will

take place in the ocean, the requirements of Sections 102 and 103 of the MPRSA

must be met. These, like the requirements of the CWA, are concerned with the

environmental impacts due to disposal of the dredged material. Neither of

these Federal acts specifically deals with the environmental impacts from inplace sediments, only those associated with disposal. However, for Federal

projects, the National Environmental Policy Act (NEPA) and the Council on Environmental Quality implementing regulations require, in the evaluation process, identification and assessment of reasonable and feasible alternatives.

This assessment must include an evaluation of the existing condition and the

consequences of the no-action alternative.

Due to public concern, the major area of emphasis under these regulations

has been on the short-term impacts of dredging on water quality and the adjacent areas and the impact of disposal of sediments on the terrestrial or

aquatic environment. The costs and benefits associated with removal of sediments have dealt with social and economic issues, since they are easily obtained from the project sponsor. The environmental impacts, both positive and

negative, of removing sediments have not been assessed due to the lack of a

documented process that allows for a quantification of impacts. As a result,

environmental documentation has generally addressed only the environmental

cost to the project of sediment disposal. Although this addresses the public

concern and meets the legislative requirements, the long-term environmental

benefits that may be incurred from the removal of contaminated sediments are

not factored into the project's cost-benefit ratio. For Federal projects that

require mitigation under NEPA, the lack of considering the benefits gained by

removing a contaminated source may result in unnecessarily increasing the economic cost of the project.

BASIC CONCEPT

The basic idea is to allow the project planner the ability to identify

and quantify environmental impacts from in-place sediments on the water quality of the water body, thereby allowing for an accurate evaluation of the

project cost versus benefits from removing the existing sediments. Various

factors will influence this assessment, including sediment characteristics,

concentration and type of contaminants in the sediments, system hydrodynamics,

contaminant sources, and existing and proposed uses of the water body. These

and other factors will significantly affect the identification and quantification of impacts. Although many of these factors can be determined through

existing data and information, others will require data collection and analysis. Without a delineated approach that provides a logical and systematic

procedure to assess in-place sediments, the results may be of limited value

due to misdirected efforts or inadequate data and analyses.

119
ACTIVITIES

Assessment of in-place contaminated sediments has a number of applications. Listed are five potential applications where the CE has direct responsibility or is involved as a cooperating agency. Also included is a short

description of the issues that can be addressed for each activity. Without

exception, the evaluation of in-place contaminated sediments as part of the

project's environmental studies would enhance the data base for evaluating the

existing conditions and the proposed action(s).

Federal Operation and

Maintenance Navigation

For those maintenance dredging activities that involve contaminated sediments, the benefits gained are currently calculated in economic terms. However, disposal of this material is based on both environmental and economic

considerations. Due to Federal environmental legislation, environmental issues normally govern the means of disposal. Therefore, the analysis conducted

is based on meeting Federal requirements (404/103) for disposal of the dredged

material. Currently the assessment does not address the influence of in-place

sediments on the water column and, therefore, the data base for evaluating

baseline conditions is restricted to the disposal site(s). With a better understanding of existing sediment conditions, economic factors as well as the

environmental benefits from removing and isolating these sediments can be calculated and used in evaluating the project cost-benefit ratio.

Permit Activities

As a regulatory agency, the CE is required under the CWA and MPRSA to

evaluate and permit the disposal of dredged material within the navigable

waters of the United States. A major component of this process is evaluating

those environmental factors delineated under the two acts, including determining the need for the proposed activity. By incorporating in the assessment an

evaluation of in-place contaminated sediments, the CE would enhance its ability to weigh the need for the project as well as the environmental cost and

benefits.

Superfund Sites

For those sites classified as Superfund sites, the presence of a known

contaminant(s) at a c-ertain concentration has been deemed harmful to humans.

As a result, actions to reduce or eliminate these contaminants are considered

necessary. However, for many of the aquatic Superfund sites, data on the impacts of in-place sediments are limited to bulk sediment contaminant concentrations. Data are lacking to: (a) evaluate the benefits of alternative

cleanup measures; (b) define "clean" (e.g., what are acceptable levels of contaminants in the sediments); and (c) determine the impact of the sediments on

the environment if no action occurs. To quantify the impacts of in-place contaminated sediments, a data base to address items a, b, and c is required.

Reservoirs

Many of the Nation's reservoirs have received materials that contain high

concentrations of nutrients and toxic materials from the surrounding

120
watershed. The increase of nutrients through runoff from man-altered environments has had a significant effect on the levels of nutrients in reservoir

sediments. With the development of anoxic conditions in the reservoir, many

of these nutrients are released and can provide conditions conducive to noxious algal blooms. With the accumulation and release of nutrients over a period of years, the reservoir will become eutrophic, and this process may

adversely affect the existing and proposed uses of the lake. Restrictions on

water contact sports, fishing, and domestic water supply are only a few of the

consequences resulting from the presence of elevated nutrients in the sediments. Also, reservoirs can be a receiving body for toxic materials discharged by industry or man-modified lands. Through identification of these

man-induced materials and assessment of their impact, remedial actions, if

necessary, can be determined and evaluated as to their effectiveness.

Toxic Spills and Hotspots

In its role as a regulatory agency, the CE must evaluate and authorize

dredging and disposal activities in the navigable waters of the United States.

For those situations where toxic materials may have been introduced into the

aquatic environment, it is important to determine the environmental impacts

from the presence of these materials. Without this information, delineating a

remedial action is, at best, difficult. Both economic and environmental cost

and benefits must be considered to determine the most appropriate cleanup

measure.

BENEFITS

Five basic benefits can be incurred from the assessment of in-place sediments. These benefits, although not associated with each of the above-cited

activities, will provide for as improvement in the CE's ability to construct

and maintain water resource projects. These basic benefits are:

a. Quantifying existing conditions, thereby providing a baseline for

decisionmaking.

b. Providing a baseline to assess the potential benefits and cost associated with each proposed alternative.

c. Quantifying project benefits incurred from removal or modification of

in-place contaminated sediments.

d. Providing for quantification of project cost and benefits gained for

the proposed action.

e. Providing a baseline for assessing the short-term as well as the

long-term benefits and cost from various long-term management

strategies.

APPROACH

The conceptual process of developing and implementing an assessment protocol for in-place sediments is presented as a three-phase approach. Each

phase consists of a series of steps or essential activities that lead to the

development of specific data and information necessary to determine the impact

121
of the sediments on water quality. The intent of this process is to quantify

cost and benefits associated with specific alternatives as they relate to impacts from in-place contaminated sediments.

Phase I

This phase is intended to serve as the first level of assessment. At a

minimum, this phase requires the defining of assessment objectives (e.g.,

cleanup and alternative evaluation), thereby determining the level of data and

analyses required for decisionmaking. Once the objectives for the assessment

are defined, the next step is the identification and collection of existing

data. Usually a wealth of information is available from various Federal and

state sources. The intent under Phase I is to minimize field data-collection

activities; thus, a decision is needed as to the sufficiency of the existing

data for evaluating the impact of in-place sediments. If existing data are

insufficient, data gaps are identified, validated, and screened based on factors such as potential for development and the time and resources needed to

fill the gaps. If the needs are valid, a data-collection effort is planned.

Unvalidated requirements result in either no further evaluation of the inplace sediments or a reassessment of the study objectives. Once the initial

data requirements are met or, if necessary, additional data requirements are

identified, Phase I is completed.

Phase II

This phase consists of collecting required additional data and conducting

a data analysis of sufficient detail to evaluate the impact of in-place sediments as they relate to the objectives delineated under Phase I.

Phase III

This phase uses the results obtained under Phases I and II to conduct the

detailed evaluation required to address the study objectives. This process

will occur in conjunction with alternative evaluations that consider engineering, economic, social, and environmental cost and benefits.

In addition to Phases I through III, consideration must also be given to

the implementation of any alternative or proposed action and monitoring of the

results. Without a feedback mechanism, the validity of the analysis of both

the impact of in-place sediments on water quality and the benefits from their

removal or alteration cannot be fully known.

CASE STUDY

At the request of the US Army Engineer District, Chicago, the impact of

in-place contaminated sediments on the water quality in the Grand Calumet

River/Indiana Harbor Canal (GCR/IHC) system was investigated during the period

1985 to 1986 in conjunction with a study on disposal alternatives for PCBcontaminated sediments from Indiana Harbor (US Army Engineer Waterways Experiment Station 1987). It was the intent of the Chicago District to use the results of this study to identify and quantify the potential benefits gained

from dredging contaminated sediments from a Federally maintained project,

thereby removing a continuing contaminant source for Lake Michigan. The

US Environmental Protection Agency was also interested in the approach used in

122
the study for assessing cleanup alternatives for the GCR/IHC system. The

approach used in this study was limited to the assessment of existing data. A

brief discussion from the report of the study results (Brannon et al. 1986) is

provided to illustrate the approach and its limitations and strengths.

The approach used for the evaluation consisted of obtaining and analyzing

existing information obtained from Federal and non-Federal sources, including

data files, in-house and published agency reports, and literature from scientific publications. The analysis focused on sediment-water interactions and

their relationship to water quality, methods for estimating impacts of

sediment-water interactions on water quality, and sediment and water quality

data from the GCR/IHC system.

The scientific literature consistently identified the movement of suspended sediment as the major mechanism for transport of sediment-associated

contaminants. Other routes of contaminant mobilization from the sediment are

through release of adsorbed contaminants from resuspended sediments and diffusion of contaminants from in-place sediment. Based on the literature and system data, the relative importance of mechanisms controlling contaminant

movement from sediment in the GCR/IHC is in the following order: transport of

contamincints associated with particulates > transport of contaminants desorbed

from suspended particulates > transport of soluble contaminants released from

deposited sediment. Another mechanism for contaminant movement is through

bioaccumulation. At present, this last mechanism is of minor importance due

to the limited numbers of pollution-tolerant fish and low numbers of less

pollution-tolerant fish species in the GCR/IHC.

Sediment oxygen demand (SOD) is an important oxygen consumption process

and is also instrumental in turning on and off the sediment surface layer as a

"valve" for oxidized and reduced materials. The SOD is also a key parameter

in water quality models that include dissolved oxygen utilization and balance.

From the data available for waterways in the Chicago area, it appears that SOD

is frequently found to be quite high; this is not unexpected in streams that

are moderately to heavily polluted. The values given in published reports for

the GCR/IHC are much lower than values given for similarly polluted streams in

the Chicago area and thus are probably too low. Therefore, it is not possible

to state with any degree of certainty the existing SOD values for the GCR/IHC

system without laboratory or field studies.

Diffusion rates of PCBs into the water column from deposited sediments

were developed by estimating equilibrium partitioning values of PCBs in sediment interstitial waters and appropriate diffusion equations. The estimated

diffusion rates of PCBs in the sediments indicated that, in the absence of

disturbances, movement of soluble PCBs is relatively minor. On the average,

I sq m of bottom sediment would annually contribute 0.025 ng of PCBs to the

overlying water. This value would be increased in the presence of bioturbation, but would remain a fairly minor component of contaminant input into the

overlying water.

Results of equilibrium partitioning calculations made using data specific

for the GCR/IHC system indicate that Food and Drug Administration limits on

PCB concentrations in fish tissue for human consumption will be exceeded; this

is provided that fish remain in the Indiana Harbor Canal for a sufficient

period to come to equilibrium with sediment PCBs. Unfortunately, equilibrium

123
partitioning cannot be conducted on compounds other than hydrophobic organic

compounds for which sediment data are available. As a result, this procedure

is restricted in evaluating polar organic compounds, heavy metals, and those

hydrophobic organic compounds known to be present in the Indiana Harbor Canal

sediments, but for which sediment data are unavailable. In addition, a major

weakness of the equilibrium partitioning approach is that the time necessary

to reach equilibrium between sediment contaminants and the biota is unknown.

Based on a number of wastewater allocation models and water quality monitoring studies, estimates have been made on a number of pollutants from combined sewer overflows (CSOs) and urban runoff. However, pollutant loading

estimates from other sources including waste fills are lacking. This information, along with data on toxic organic loadings from point and nonpoint

sources, is essential to determine contaminant loading to Indiana Harbor.

To evaluate the benefits of dredging the Indiana Harbor Federal channel,

knowledge of sediment sources and contaminant loading and how these contaminants move through the system is necessary. At present, this information is

lacking; however, based on past studies of other harbor systems, it is anticipated that CSOs and urban runoff can be significant sources of sediments and

contaminants during storm events. Further, these sources of contaminant and

sediment may be the major long-term contributors to the Federal channel in the

Indiana Harbor.

Under nondredging conditions, there are two major avenues for the resuspension and transport of sediment from the GCR/IHC system--normal ship traffic

and storm events. Examination of data from bathymetric surveys for the years

1972, 1976, 1980, and 1984 indicates that Indiana Harbor Canal has reached a

shoaled equilibrium with the channel thalweg provided by passage of boat traffic. A sharp decrease in the channel depth was found between the years 1972

and 1976, with progressively smaller depth changes since 1976. The 1984 survey shows only a small overall change from the 1980 survey, an indication that

the total amount of shoal material has not changed but may only be

redistributed.

The data base for the GCR/IHC has only limited data on contaminant releases during interactions between suspended sediment and water. Velocity

data and information on sediment resuspension are also very limited. To determine the mass of contaminants transported from the sediments during dredging

and nondredging conditions, it will probably be necessary to use mathematical

models. Further, prediction of the ultimate fate of contaminants in the

GCR/IHC system, required for evaluation of overall water quality, may be aided

by the use of contaminant models, but additional field and laboratory data

should be obtained prior to intensive contaminant fate modeling studies.

Results of this study have shown that the available data allow only rough

estimates, such as those in the CE's Indiana Harbor Environmental Impact

Statement, of the sediment loadings, sediment yield, and benefits that would

accrue from dredging the Indiana Harbor Canal. Historical dredging data

strongly suggest, however, that dredging the Indiana Harbor Canal would allow

it to act as a sediment trap, retaining contaminated sediment that would

otherwise be transported into Lake Michigan. Additional data must also be

collected before analytical techniques more sophisticated than those already

employed can be applied to the GCR/IHC system for either metals or toxic

124
organics. More detailed hydrodynamic and suspended sediment transport data

are also necessary to allow use of more sophisticated analytical techniques

for evaluating sediment sources, sediment resuspension, and sediment transport. Therefore, the immediate detailed application of either hydrodynamic or

contaminant models is not recommended.

SUMMARY AND CONCLUSIONS

This paper reviews a concept that can be used by CE planners to identify

and quantify the environmental impacts from in-place contaminated sediments on

a water body. The concept can be applied through a three-phase approach that

allows quantification of cost and benefits associated with in-place sediments

and proposed actions. By using a three-phase approach that incorporates the

maximum use of existing data during Phase I, cost for field data collection

and analyses can be minimized. Further, by using a phased approach, decision

points can be incorporated during each phase for assessing the proposed benefits to be gained from collection and analyses of additional data, which may

be disproportionate to the incurred cost.

In the GCR/IHC case study, the approach was limited to Phase I, with limited data collection under Phase II. Based on the analyses of existing data,

it was concluded that insufficient data exist to quantify benefits. A report

was prepared that delineated the findings and made recommendations on additional studies. To provide for flexibility, recommendations for future studies were given at three study levels. This approach allows the Chicago District the option of tailoring studies to meet specific objectives for maximum

benefit at lowest cost.

ACKNOWLEDGMENTS

This study was sponsored in part by the Office, Chief of Engineers, under

the Dredging Operations Technical Support Program. The case study was sponsored by the Chicago District. The authors acknowledge the assistance of

Mr. Jan Miller of the Chicago District and Messrs. James Martin and

Daniel Averett of the US Army Engineer Waterways Experiment Station in the

conduct of this study.

REFERENCES

Brannon, J. M., Gunnison, D., Averett, A., Martin, J., Chen, R., and Athow,

R. F., Jr. 1986. "Analyses of Impacts of Bottom Sediments from Grand Calumet

River and Indiana Harbor Canal on Water Quality," prepared for US Army

Engineer District, Chicago, by US Army Engineer Waterways Experiment Station,

Vicksburg, Miss.

US Army Engineer Waterways Experiment Station. 1987. "Disposal Alternatives

for PCB-Contaminated Sediments from Indiana Harbor, Indiana," Miscellaneous

Paper EL-87-9, 2 vols, Vicksburg, Miss.

125
RECENT STUDIES CONCERNING THE CAPPING OF

CONTAMINATED DREDGED MATERIAL

R. W. Morton

Science Applications International Corporation

Admiral's Gate U) 221 Third Street

0Vo Newport, Rhode Island 02840

ABSTRACT

•Disposal of contaminated sediments in the marine

__environment through "capping" with cleaner materials

•___is a management option that has been used extensively

during recent years, particularly in the New England

- region. Most of the capping projects have been restricted to quiescent, shallow-water (20 to 30 m) en-

-. vironments; however, as a result of monitoring

programs associated with these projects, a body of

knowledge concerning the creation of capped disposal

mounds has been developed that can be used to predict

the consequences of extending such procedures to

deeper waters. The application of capping technology

to deeper water is extremely important, because disposal site designation programs currently under way

throughout the United States are predominantly aimed

at water depths of 100 m or greater. Recent field

studies at the New York Experimental Mud Dump (EMD)

site and the Foul Area Disposal Site (FADS) in Massachusetts Bay have utilized modern instrumentation and

sampling procedures to examine the long-term stability

of capped deposits in the open ocean and to predict

the behavior of both contaminated and cleaner capping

materials during disposal operations in water depths

approaching 100 m. The results of these studies confirm that, with proper disposal management, capping in

-deeper waters should be considered as a feasible option for disposal of contaminated sediments.

INTRODUCTION

Capping of contaminated dredged material with sediment relatively free of

contaminants has been used for a number of years as a management technique for

reducing the potential environmental impact of open-water disposal. The approach, which has been used successfully in a number of areas, was first employed in 1977 by the New England Division of the Corps of Engineers at the

New London Disposal Site (NLDS). This project took place in 20 m of water

south of the Thames River in the eastern end of Long Island Sound. The success of that operation has led to continued application and field observations

126 92-16018 IIIII 111 I /II /l/liil! Hl
of the technique, including major disposal operations at the Central Long

Island Sound (CLIS) disposal site and at the New York EMD site in open ocean

waters. Additional studies, stressing laboratory observations on the effectiveness of capping, have been conducted at the US Army Engineer Waterways

Experiment Station (WES).

As a results of these studies, a great deal has been learned relative to

the effectiveness of capping in the marine environment. However, during each

proposed capping operation, major issues must be addressed and fully understood for that specific project to ensure accurate prediction of the behavior

of both contaminated and capping material. These issues include:

a. Thickness of the cap - related to the effectiveness of the capping

material in isolating the contaminants, particularly the potential

for leaching of contaminants and effects of bioturbation.

b. Placement of the cap - related to navigation control ddring disposal

to ensure coverage of contaminated sediments, and to the mixing and

displacement of contaminated sediment by the capping material.

c. Stability of the cap - related to the support of the cap by typical

contaminated material (high in water content) and resistance to erosion and transport of capping material.

Previous studies of capping have indicated that, with careful management,

the operation can be successful in relatively quiescent, shallow waters. However, the major issues with regard to capping in the United States are now

related to the depth at which capping can be accomplished. Designation of new

disposal sites in water depths greater than 100 m, where capping will be a

management option, are currently under way in the New England region, at the

FADS in Massachusetts Bay, in the Seattle area at the Everett Homeport disposal site, and potentially in the New York region at a site to the designated

farther offshore than the EMD site.

Permits for capping of contaminated sediments at these deeper disposal

sites will certainly require monitoring of the disposal operation and the resulting deposit. Recent advances in instrumentation and sampling procedures

permit reliable monitoring of capping projects and effective management and

control of the disposal operations. Examples of the instrumentation used for

execution and monitoring of deeper capping projects include:

a. Precision navigation - ensures correct placement of contaminated and

capping sediments and accurate sampling of abrupt transitions during

monitoring programs.

b. Precision bathymetry - allows sequential monitoring of the mass balance of sediment at the disposal site to assess the effectiveness of

capping and long-term stability of the cap.

c. Advanced acoustic measurements - plume tracking instrumentation that

measures the dispersal of sediments during disposal while sidescan

sonars and subbottom profilers provide accurate measurement of sediment distribution in the vicinity of the capped disposal mound.

127
d. Sediment profile photography - REMOTS provides the ability to assess

the distribution and characteristics of near-surface sediments, particularly the cap material, with a resolution unattainable with

acoustic measurements or conventional sampling procedures.

This paper briefly reviews the results of previous capping operations to

place the current work in perspective and to emphasize recent measurements

that address the feasibility of extending the capping option to deeper waters.

HISTORY OF CAPPING OPERATIONS

The first example of capping used as a disposal management strategy

occurred at the NLDS in 1977 when contaminated sediments from the vicinity of

dock areas were dredged and covered with progressively cleaner sediments as

dredging proceeded from the head of the estuary to the mouth. Capping of the

contaminated sediments was ensured, because the mass of material used for capping was more than 30 times greater than that of the contaminated material.

However, such an abundance of capping material is not always available, and

for capping to become a truly feasible management strategy, procedures for

capping with much less material had to be developed.

The first field study of controlled capping of contaminated material with

more reasonable amounts of capping material took place at the CLIS in 1979.

During this project, two disposal mounds were formed, each with approximately

30,000 cu m of contaminated sediments from Stamford, Conn. These deposits

were then capped, one with approximately 76,000 cu m of silt and the other

with 33,000 cu m of sand dredged from New Haven harbor. This study produced

several important conclusions, outlined below, which were applied to future

capping projects.

a. Disposal of contaminated sediments must be tightly controlled. This

is necessary to reduce the spatial distribution of material to be

capped and can be accomplished through use of taut-wire disposal

buoys or precision navigation control.

b. Disposal of capping material must be spread over larger area. Dispersal of cap material is necessary to ensure adequate capping of

the margins of the contaminated deposit and is particularly important for silt capping material, which does not spread as evenly as

sand.

c. Silt develops thicker cap than sand. Silt caps do not disperse as

readily during disposal; however, the greater thickness is needed

because the depth of bioturbation reaches deeper in silt than in

sand.

d. Silt cap recolonized with fauna similar to surrounding silt environment; sand cap, with completely different species. Recolonization

of both mounds occurred as expected, and impacts to the surrounding

environment appear negligible.

e. Caps are resistant to erosion. Once stabilized, both the silt and

sand caps have remained essentially unchanged for more than 8 years

(including two hurricanes).

128
A second study, utilizing similar sediments, was conducted 2 years later

with comparable results. In this study the placement of capping material was

the most significant factor affecting the isolation of contaminated sediments.

In spite of efforts to distribute the cap evenly, additional disposal of silt

material was required to achieve adequate coverage.

Other capping operations that have been successfully accomplished since

1979 include:

a. Disposal and capping in borrow pits. This approach has been suggested

as an alternative for New York Harbor, but is currently on hold pending studies of the environmental significance of the borrow pits.

b. Dredging of a depression, filling with contaminated sediments, and

capping with displaced material. Successfully accomplished in Norwalk, Conn., but restricted to shallow-water environments. This

approach has been proposed for disposal of PCB-contaminated sediments

at the New Bedford Superfund site.

c. Open-water capping at the New York EMD site. Successful disposal of

522,000 cu m of contaminated material covered by 1,200,000 cu m of

clean sand that has persisted on the open shelf for 7 years. Excellent management of continuous capping operations within the EMD

site requires identification of cap material prior to issuing permit

for disposal of contaminated sediments.

As a result of these studies, the factors affecting capping can be predicted with some accuracy, particularly the amount of material needed to

create an effective cap and the controls necessary to dispose of the contaminated sediment and capping material in a stable deposit.

RECENT CAPPING OBSERVATIONS

Two major field studies recently completed at the New York EMD site and

the FADS in Massachusetts Bay have made extensive use of new monitoring tools

and procedures to develop integrated and comprehensive analysis of the environmental effects of capping contaminated sediments. The objectives of the

study at the EMD were to assess the long-term (5 years) stability of the sand

cap deposited over the contaminated sediments in the open-shelf environment.

The objectives of the FADS study were to assess the behavior and distribution

of sediments deposited under carefully controlled conditions in water 90 m

deep to evaluate the feasibility of capping in such water depths. The following paragraphs provide an overview of the results of those studies as they

apply to future capping operations in deep-water environments.

Experimental Mud Dump Site

During November 1986, Science Applications International Corporation, in

cooperation with the New York District and under contract to the WES, conducted extensive field observations at the EMD. The objectives of this program were to:

a. Provide accurate bathymetric data to describe the overall topography

of the Mud Dump Site (MDS).

129
b. Define conditions at the boundaries of the HDS.

c. Assess the long-term stability of the sand cap within the END.

d. Investigate bioturbation on the sand cap.

e. Make recommendations for a long-term monitoring program for the EMD

and MDS.

The environmental sensor systems used to conduct these studies included:

a. Computerized Navigation and Data Acquisition System - used to provide

accurate control of sampling and survey locations and to acquire

precision bathymetric data for comparison with previous surveys.

b. Computerized Subbottom Profiler System - used to provide continuous

record of cap thickness for comparison with cores obtained immediately following disposal.

c. REMOTS Sediment Profile Camera - used to map the distribution of

small-scale dredged material layers, to detect the presence of the

sand cap on the margins of the site, and to assess the status of infaunal recolonization on the cap material.

The precision bathymetric survey acquired during this project (Figure 1)

was compared with data obtained by the New York District immediately following

disposal of the cap material through development of contour difference charts.

The early survey data were digitized and corrected, assuming no change in the

ambient depth of the bottom, to allow comparison between pre- and post-capping

topography and with the existing topography as determined by the current survey. Results of these comparisons indicated that a cap of approximately 1.5

to 2 m covered most of the contaminated material (Figure 2) and that this cap

was essentially unchanged during the following 5 years (Figure 3).

This result was supported by the subbottom profile measurements that indicated a surface deposit of more than 75-percent sand over the disposal area

(Figure 4) with a mean thickness of 1.5 m in the vicinity of the disposal

mound (Figure 5). Subbottom profiles across the disposal site (Figure 6)

demonstrated that the cap was continuous and that patches of fine-grained material that were observed on the surface of the mound were underlain by sand,

suggesting intermittent deposition on the surface of the mound.

The REMOTS photography also indicated that the sand cap was in place over

the disposal site. The "Benthic Process" map (Figure 7) shows clean, finegrained, high-reflectance sand in the vicinity of the EMD covering an area of

500 by 700 m. However, the photographs taken within this area also show bed

forms and, in some cases, alternating layers of sand and mud. These photographs suggest that there is some sediment resuspension and movement on the

surface of the mound, but that the entire region must be in equilibrium, because there has been no significant loss of cap material over time.

The recolonization of the disposal mound also indicates that disturbance

of the surface occurs, because Stage I (opportunistic) species are the predominant infaunal successional stage on the disposal mound (Figure 8). However,

130
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138
it should be noted that Stage I species are present throughout the disposal

site, suggesting relatively active bottom conditions. The presence of Stage I

species on the sand cap means that bioturbation will penetrate only a few centimetres into the cap, and therefore, isolation of the contaminated material

can be expected. On the flanks of the mound, where the cap thickness is not

so great and some Stage III organisms are present, mixing of the contaminated

sediment can be expected.

In summary, the cap at the END has persisted for a period of 5 years,

with no significant loss of material. It has maintained equilibrium with the

surrounding environment so that a thickness of 1.5 m over most of the disposal

site remains as an effective cap for isolation of contaminated materials. The

fact that this cap has persisted in relatively shallow (20 to 30 m), exposed

waters suggests that containment of contaminated materials can be accomplished

even in relatively high-energy environments.

Foul Area Disposal Site

During 1986 and 1987, extensive disposal site designation studies were

undertaken at FADS, which included investigation as to the potential effects

of capping operations in the 90-m water depths encountered. Disposal at FADS

is generally conducted from disposal scows, and occasionally from hopper

dredges. Sediment is transported to the bottom in the classical manner,

resulting in the three phases of disposal which affect the behavior of dredged

material:

a. The Convective Descent Phase, during which the majority of the

dredged material is transported to the bottom under the influence of

gravity as a concentrated cloud of material.

b. The Dynamic Collapse Phase, following impact with the bottom where

the vertical momentum present during the Convective Descent Phase is

transferred to horizontal spreading of the material.

c. The Passive Dispersion Phase, following loss of momentum from the

disposal operation, when ambient currents and turbulence determine

the transport and spread of material.

In shallow water, cohesive sediments disposed by clamshell/scow operations create a distinct mound formation with thin flank deposits, while sands

or less c hesive, high water-content sediments characteristic of the contaminated material will produce a broader, more uniform deposit. At FADS, any

mounding of cohesive sediments would be less prevalent because the deeper

water causes more entrainment of water during the Convective Descent Phase and

a larger radius of impact.

The fact that the dredged material reaches the bottom during the Convective Descent Phase is important for assessing the potential transport and

spread of material during the disposal process. The rate of convective descent has been measured as approximately I m/sec during three separate disposal operations. Therefore, at the FADS site, where the average depth is

approximately 90 m, the majority of material can be expected to impact the

bottom within 2 min of disposal. Because the maximum current velocities measured at FADS were approximately 30 cm/sec, the worst-case transport of

139
material during convective descent would amount to only 36 m. This is well

within the error of positioning of the disposal vessels and, therefore, the

effect of currents on the shape or distribution of the disposed contaminated

dredged material or cap deposit would be negligible.

Regardless of whether the disposal operation is conducted with a hopper

dredge or scow, both theoretical and observational data indicate that the majority of the dredged material will be transported to the bottom at FADS as a

discrete plume during the convective descent phase. When this material

reaches the bottom, the vertical momentum will be transferred to horizontal

momentum during the dynamic collapse phase. Depending on the geotechnical

properties of the sediment, one of two types of deposit will form. If the

material consists primarily of cohesive silt, a concentration of cohesive

clumps, interspersed with soft mud, will be created. This deposit will be

surrounded by a deposit of mud that extends beyond the clump area for some

distance. If the material is sand or noncohesive silt, the deposit can be expected to be more uniform. In either case, the overall spread of the material

will be similar, because the potential energy available for both types of disposal is essentially identical and the transfer of vertical to horizontal momentum will take place in the same manner when the material impacts the

bottom. The main difference in the deposit results from the distribution of

kinetic energy between the large cohesive clumps, which will absorb a great

deal of energy with little horizontal movement, and the more fluid muds, which

will readily flow until that energy is dissipated.

The overall size and thickness of the resulting disposal mound depend on

the amount of material disposed at the site and the navigation control exercised during the disposal effort. To ensure that disposal of contaminated

dredged material occurred in a controlled manner, a taut-wire moored buoy was

deployed at this site. Using such a buoy, restriction of the disposal operation to a 50-m radius was possible, and the input of dredged material could be

considered as a point source. In this manner, overall management of the distribution of the contaminated dredged material was possible through controlled

placement of the buoy.

Recent work using the REMOTS camera, completed in January 1987, has demonstrated that the disposal of dredged material under tight control at FADS

resulted in a broad, low deposit spread evenly over an area similar to that

covered by disposal in more shallow waters. The major difference in the deposits results from the greater spread of cohesive clumps, which inhibits formation of the topographic feature (i.e., disposal mound). Figure 9 indicates

the distribution of dredged material as detected by the REMOTS camera following disposal of approximately 200,000 cu m. This operation resulted in a deposit with a thin layer of dredged material extending over a circular area

with a radius of 500 m, a distance corparable to similar volumes deposited in

the shallow water of Long Island Sound.

Figure 10 presents a schematic of the results of disposal in shallow

water, as compared with the deeper water of the FADS. The major difference

between the two regions results from the loss of kinetic energy through entrainment of water during the convective descent phase so that, in deeper

water when bottom impact occurs, the lateral motion during dynamic collapse is

substantially less than in shallow water. The result is a more uniform, broad

deposit over essentially the same area of bottom.

140
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Figure 10. Comparison of dredged material deposit created in shallow

(20-m) and deep (90-m) water

142
The effect of these phenomena on mitigating measures such as capping can

have important implications for disposal management. Because the spread of

material occurs mostly during the convective descent phase rather than the dynamic collapse phase, even small amounts of material will cover the same bottom area as larger volumes. Consequently, it would take essentially the same

amount of material to effectively cap 100,000 cu m of contaminated material as

possibly 250,000 cu m. Assuming such deposits covered an area of bottom with

a 500-m radius, similar to the deposit created during the 1986 disposal operations, at least 1.1 x 106 cu m of material would be required to produce a

deposit 1 m thick extending 100 m beyond the edge of dredged material. This

is not an unreasonable quantity to cover a substantial project, but would be

untenable for a small contamination problem. Table I presents the volume of

material required to cap contaminated material covering a range of areas.

In summary, although capping has not been conducted at FADS, previous

disposal operations have demonstrated the effectiveness of disposal control in

restricting the spread of material. This is the single most important factor

in a capping operation and, if the disposal location is a containment site,

then given sufficient material, capping should be feasible.

CONCLUSIONS

Recent field monitoring programs of dredged material disposal in the

marine environment using modern instrumentation have resulted in general confirmation that capping is a viable mitigating measure for disposal of contaminated sediment. Long-term studies of existing capped disposal mounds have

demonstrated that these deposits are generally stable and in equilibrium with

the existing environments even under relatively high-energy, open-ocean shelf

conditions. Furthermore, with careful management of the disposal operation,

it is clear that placement of the contaminated and cap material can be conducted effectively even in water depths approaching 100 m.

As in all ocean disposal operations, the development and implementation

of a rigorous disposal management plan is essential to the successful accomplishment of capping. This management should include a continuous monitoring

program, making use of the latest available technology, to ensure that both

the operation itself and the resulting deposit conform to expected parameters.

143
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RELATIONSHIP BETWEEN SEDIMENT POLLUTION AND MACROBENTHIC

COMMUNITIES IN HIROSHIMA BAY, JAPAN

K. Yoshida

Japan Sediments Management Association

No. 15 Sankyo Building, 5th Floor, 7-12,

Tsukiji 2-chome, Chuo-ku, Tokyo 104

ABSTRACT

WO Distribution of sediment, macrobenthos, and the

anoxic water mass in Hiroshima Bay was investigated.

= The accumulation of organic matter in the sediment was

____- considerable in the semi-closed bays, such as Kure and

__Edajima, and in the mouth of the Ota River. In Kure

t0• Bay, particularly, the benthic communities were of -• very poor condition or had disappeared, apparently due

to the anoxic water mass. It is thought that the oc-

-• currence of the anoxic water mass in Kure Bay was

-n mainly caused by the oxygen demand due to decomposition of the organic matter in the sediment, which can

be determined from the distribution of the temperature, salinity, and dissolved oxygen and from the sub-

____ tidal current.

INTRODUCTION

Background

Bottom-water anoxia is considerable in semi-enclosed bays, such as the

Inland Sea and Mikawa and Tokyo Bays on the coast of Japan. The Inland Sea

alone contains more than 10 small bays and seas, and for some of them, the

occurrence of an anoxic water mass and its effects on the macrobenthos have

been reported (Shimada 1983). Anoxic water masses have occurred in HiuchiNada and Harima-Nada Seas during summers. In the summer of 1972, these seas

experienced a great decline in fish and shellfish due to a large-scale anoxic

water mass (Imabayashi 1983). Also, in Osaka Bay, it was reported that the

benthic community was greatly affected by the anoxic water mass (Jo, Yamochi,

and Abe 1978a, b).

A decline in fish and shellfish due to the occurrence of a large-scale

anoxic water mass was also reported in Mikawa Bay (Aichi Prefecture Fisheries

Experimental Station 1973, 1974), and a similar decline has become serious in

Tokyo Bay. The occurrences and upwellings of anoxic water are called "blue

tide" because they appear blue (or white) as a result of the surface flow with

wind blowing.

In every area where an anoxic water mass has been noted, pollution from

organic matter was evident; thus, it can be assumed that the oxygen demand of

145 92-16019 SlIIll IB IIIlI I! II I!
the organic matter caused the anoxic water mass occurrences. Therefore, ii1

discussing the effects of sediment pollution on macrobenthos, we must consider

the anoxic water mass occurrences as well as heavy metals and artificial organic matter. This paper summarizes a study of an anoxic water mass and its

effects on the macrobenthic communities of Hiroshima Bay (particularly

Kure Bay).

Description of Hiroshima Bay

Hiroshima Bay is located in western Japan, in the western portion of the

Inland Sea. The surface area is 946-km2 wide, with a volume of 24.2 km3 (Figure 1). The bay is dotted with many small islands. The sea to the north of

Itsukushima, Nomijima, Edajima, and Kurahashijima Islands is divided into two

semi-enclosed bays, Edajima and Kure. The sea bottom is generally plain, with

a limited portion of shoal along the seacoast and a sea valley along the

channel.

The main rivers draining into the bay are Ota, Seno, and Yahata in the

northern end of the bay and Nishiki, Kose, and Megumi in the western •art of

the midbay. The flux volumes in summer are approximately 6 million m per day

for Ota River, 4 million m3 per day for Nishiki River, 1 million m3 per day

for Kose River, and under 0.3 million m3 per day for the other rivers.

The flood tide enters the bay south of Kurahshijima Island, heads north,

and enters Kure Bay, turning to the northeast. The ebb tide flows out, heading toward the opposite direction. Tide speeds are approximately 10 cm/sec in

the northern end of the bay, approximately 20 cm/sec in the midbay, and 30 to

40 cm/sec at the mouth and channel of the bay (Figure 2) (Third District Port

Construction Bureau of the Transportation Ministry 1980).

STUDY DESCRIPTION

Observations in 1982

Observations of water quality (June-October), sediment (August), and benthic communities were performed in 1982 at the stations shown in Figure 3.

Water temperature and salinity were measured by electric water thermometer and salinometer. Water was sampled from the surface and the bottom with

an insulated water sampler. The sediment was sampled by divers with an

acrylic core sampler. The upper 5-cm portion was separated. The samples were

analyzed for organic content (by ignition loss, 9000 C, 2 hr), chemical oxygen

demand (consumption of potassium permanganate), and sulfide (distillation by

steam-lodometry).

Benthic communities were sampled with a Smith-McIntyre sampler and sieved

with a 1-mm sieve. Organisms were fixed in formalin.

Observations in 1983

From July through October, dissolved oxygen (DO) in the bottom water was

observed at 1-week intervals at observation stations in the northern end of

the bay (see Figure 4). Procedures for sampling were the same as in 1982.

146
JAPAN

HIROSHIMA

i

N 3420'

- N34eO'

0 _'Wksa

E13°20" E13230'

Figure 1. Study area, Hiroshima Bay

147
a. Flood tide

upper layer kar lae

b. Ebb tide

Figure 2. Average tidal currents (centimetres per second)

in Hiroshima Bay during the spring

148

12 iii %24 
ITA kiv.

0 0 0 IISIIM 

0 10k

e3 IU - Is

Figure 3. Observation stations in 1982

149
SITISIKIINA

lit

Figure 4. Observation stations in 1983

Experiments in 1984

At those observation stations shown in Figure 5, the sediment was sampled

by divers with an acrylic core sampler and incubated with water from directly

above it. The oxygen consumption rate was measured by analyzing diminished

oxygen in the water under a constant temperature of 250 C for 5 days.

Observations in 1984-87

At the six observation stations shown in Figure 5a, observations were

made of the water quality, the sediment, and the distribution of the macrobenthos. At the seven observations stations in Kure Bay.(shown in Figure 5b),

water quality was tested three times a month. The procedures were the same as

in the preceding years.

RESULTS AND DISCUSSION

Observations in 1982

Dissolved oxygen in the bottom water during the period July 5-October 6,

1982, is shown in Figure 6. The observed patterns indicate that the anoxic

water mass was frequently located in Edajima Bay and near the mouth of the Ota

River in the northern end of the bay.

150
[•SHINA•

20 ENNIN11. 4

. 4" s.o 6.

707.

8.00

a. Stations for sediment core b. Stations for observasampling (in 1984) and tion of anoxic water

monthly observations (May mass, three times a

1985-February 1987) month, July-October

1986

Figure 5. Observation stations during the period 1984-87

Patterns of ignition loss, chemical oxygen demand (COD), and sulfide in

the sediment sampled during June-October 1982 are shown in Figure 7. It can

be deduced from the high levels of COD and sulfide in Kure Bay, Edajima Bay,

and near the mouth of the Ota River that the accumulation of organic matter in

the sediment is significant in these areas.

DO Distribution, Summer 1983

Figure 8 shows the average DO concentrations in the sediment over the

12 samplings (conducted at 1-week intervals) during July 19-October 14, 1983.

This indicated that Kure Bay is more likely to become anoxic in its innermost

part.

Water Quality Changes, 1985-87

Figure 9 shows the changes in the water quality in Kure Bay during the

period May 1985-February 1987 (average of values at three observation stations). The highest temperature in the upper water was recorded in August,

with a lag of 1 or 2 months in the lower layer. The difference in temperature

between the upper and lower layers was greatest during July and August. There

was no outstanding transition in salinity except for the noticeable decrease

in the upper layer during June and July due to heavy rain.

151
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Figure 7. Patterns of selected sediment parameters in 1982

153
~30-40% M ~40-50% ro'Z'o3e*5 0-6O0%

.'.'*.'-'.'.J

Figure 8. Deviation of DO concentrations in bottom water of

Hiroshima Bay, July 19-October 14, 1983

Benthos Distribution, 1985-87

The distribution of the macrobenthos during the period June-October 1982

is shown in Figure 10. There were very few organisms in Kure and Edajima Bays.

The transition in the benthos distribution for May 1985-February 1987 is

shown in Figure 11. Table 1 summarizes the data on benthos. In northern and

southern Kure Bay and in the mouth of the Ota River, densities were highest.

In the center of Kure Bay, however, and in Edajima Bay, lower densities were

noted. Dominant organisms were Polychaeta, along with a few Mollusca and

Crustacea.

Jo, Yamochi, and Abe (1978a) investigated Osaka Bay with regard to water

quality and the distribution of the sediment and the benthic communities.

They concluded that the areas lacking benthos existed where large accumulations of organic matter existed in the sediment, where an anoxic water mass

can easily occur due to stratification.

154
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Figure 10. Distribution of macrobenthos, June-October 1982

156
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158
Imabayashi (1983) investigated the Hiuchi-Nada and Harima-Nada Seas and

reported that there was a strong correlation between the number of species and

the number of individuals in the benthos (its diversity index) and dissolved

oxygen in the bottom water, which suggests that the anoxic water mass caused

the change in the macrobenthos.

Table 2 shows the environmental factors at each observation station in

the innermost part of Hiroshima Bay. In the center of Kure Bay, the average

DO was almost the same as at the other observation stations. However, the

lowest DO was lower than the other stations, and the sulfide concentration

rate and DO consumption were higher. This could be the reason for the accumulation of organic matter in the sediment and the occurrences of anoxic water

mass that caused the poor-condition benthos.

Anoxic Water Mass in Kure Bay, 1986

Figure 12 shows the variation of vertical profiles of water temperature

during the period July 4-October 27, 1986. The difference in water temperature between the upper and lower water layers reached about 100 C in midAugust; in October, the temperatures were consistent. In contrast, the

surface water with highest temperature, 260 C, at observation station 7

(St. 7) in southern Kure Bay, was noticeable compared with St. 4 in the northern part of the bay.

Salinity decreased in the upper water layer in mid-July because of heavy

rain, and the same trend was recognized at the other observation stations

(Figure 13).

According to the results of the investigation by the Third District Port

Construction Bureau of the Transportation Ministry (1986), in Kure Bay, the

ebb tide in the upper water flows out from the northern bay or the channel of

Hayase; in the bottom water, it flows in at the southern bay and flows out

from the northern bay. The flood tide in the upper and bottom water flows to

the opposite direction to the ebb tide. The subtidal tide flows in at the

channel and flows out from the northern bay. At St. 7 in the southern bay,

the salinity in the sediment is higher than the other observation stations

because of the inflow of water from the open sea through the Hayase channel.

The DO distribution in the bottom water in Kure Bay is shown in Figure 14. Anoxia could be recognized on July 4 and was the most serious from

August 6, when the bedding water developed. On October 7, when the stratification of the water temperature and the salinity vanished, the anoxia in the

midbay was quite high.

Primary Causes of

Anoxia and Countermeasures

A schema of the DO balance and the primary causes of the anoxic water

mass is shown as Figure 15. The anoxic water mass seems to originate from the

seashore in northern Hiroshima Bay, but the anoxia is more pronounced in Kure

Bay. The wind-driven surface flow, which was reported in Mikawa Bay (Aichi

Prefecture Fisheries Experimental Station 1973, 1974) and in Tokyo Bay in

1986, cannot occur easily in Kure Bay. In addition, the subtidal current in

159
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Centigrade) in Kure Bay, July 4-October 27, 1986

161
Jul. Aug Sept. Oct.

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in Kure Bay, July 4-October 27, 1986

162
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Figure 14. Distribution of DO in bottom water of Kure Bay,

July 4-October 27, 1986

163
Other water mass

Dif f sike T prtatsaise

9196M Olitto FPhytoplankton Detritus -DO•

Dissolved Phyto-,Zooplankton

organicmatr! nupinmrtt

Sediment; organic matter

sulfide compounds

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. . . -- Thrtrnolino

'0Decrease of DO transportation & diffusion

Anoxic

ANOXIA -1,, -"In= Water

Transfer Mass

4 Consumption

Organic matter

or

Sulfide compounds

in

Sediment

b. Causes of anoxia

Figure 15. Schema of anoxic water mass, Kure Bay

164
the bottom water in Kure Bay flows toward the north (Third District Port Construction Bureau of the Transportation Ministry 1986). Therefore, it was determined that the anoxic water mass in Kure Bay occurs within the bay.

The reduced oxygen supply in the upper water and the development of

stratification are probably due to the strengthening of the stratification in

Osaka Bay; however, in Hiuchi-Nada Sea, it is probably due more to the decreased oxygen supply because of the stagnated coldwater mass under the second

thermocline than to the oxygen consumption in the sediment.

In Kure Bay, the anoxia is the most serious when the stratification becomes moderate, and that means the reduced oxygen supply does not cause the

occurrence of the anoxic water mass daily. The consumption of oxygen in the

sediment in Kure Bay was measured as 2 g 02 per square metre per day, which is

higher than the value for Hiuchi-Nada Sea (0.5 g 02 per square metre per day

(Ochi and Takeoka 1986), which has a great influence on the occurrence of the

anoxic water mass. Because the temperature of the bottom water was the

highest in late September, water temperature probably accelerates DO

consumption.

As a result of this study it was concluded that the occurrence of the

anoxic water mass in Kure Bay is greatly affected by the accumulation of organic pollutant in the sediment, which also contributed to a depauperate

benthic community. Thus, the most effective way to reduce the anoxic water

mass is to decrease and control the accumulation of organic pollutants in the

sediment. This will be very important for the long term.

REFERENCES

Aichi Prefecture Fisheries Experimental Station. 1973. "Study of Red Tide

and Anoxic Water Mass in Mikawa Bay," Bull. No. 9 (in Japanese).

Aichi Prefecture Fisheries Experimental Station. 1974. "Study Red Tide and

Anoxic Water Mass in Mikawa Bay (II)," Bull. No. 10 (in Japanese).

Imabayashi, H. 1983. "Effect of Oxygen-Deficient Water on the Benthic Communities," Bull. Japan Soc. Sci. Fish., Vol 49, No. 1, pp 7-15 (in Japanese).

Jo, H., Yamochi, S., and Abe, T. 1978a. "The Present Condition of Sediment

and Benthic Community in Osaka Bay, 1975," Bull. Osaka Pref. Fish. Exp. Sta.,

No. 5, pp 42-58 (in Japanese).

Jo, H., Yamochi, S., and Abe, T. 1978b. "Formation and Decay of OxygenDeficient Water Mass in Osaka Bay," Bull. Osaka Pref. Fish. Exp. Sta., No. 5,

pp 71-82 (in Japanese).

Ochi, T., and Takeoka, H. 1986. "The Anoxic Water Mass in Hiuchi-Nada;

Part 1, Distribution of the Anoxic Water Mass," J. Oceanogr. Soc. Japan,

Vol 42, No. 1, pp 1-11 (in English).

Shimada, T. 1983. "Study of the Anoxic Water Mass in Hiroshima Bay," Twelfth

Conference of the Oceanographical Survey Technique in Southern Sea and Seto

Inland Sea (publication materials) (in Japanese).

165
Third District Port Construction Bureau of the Transportation Ministry. 1980.

"The Report of the Tide Level and the Tidal Current in Hiroshima Bay."

Third District Port Construction Bureau of the Transportation Ministry. 1986.

"The Report of the Current Conditions and the Flowage of Suspended Mud in Kure

Bay" (in Japanese).

BIBLIOGRAPHY

Kakino, J. 1986. "The Causes of Bivalvia Dying in Inner Part of Tokyo Bay; A

Consideration About the Influence of Oxygen Deficient Water," Fish. Eng.,

Vol 23, No. 1, pp 41-47 (in Japanese).

Shimada, T., and Kojima, S. 1983. "Study of the Anoxic Water Mass in Hiroshima Bay," Proceedings of the 38th Annual Conference of the Japan Society of

Civil Engineers, pp 761-762 (in Japanese).

166
PILOT DREDGING STUDY, NEW BEDFORD HARBOR,

MASSACHUSETTS, SUPERFUND PROJECT

V. L. Andreliunas

US Army Engineer Division, New England

424 Trapelo Road

Waltham, Massachusetts 02254-9149

I ABSTRACT

100 Testing of sediment from the northern portion of

New Bedford Harbor, Massachusetts, has revealed that

most of the area is contaminated by polychlorinated.

biphenyls (PCBs). In August 1984, the US Environmental Protection Agency (USEPA) published a Feasibility

Study of Remedial Action Alternatives for this area,

which proposed five cleanup alternatives. Four of

-these dealt specifically with dredging the area to remove the contaminated sediments. In response to com0Q ments received, the USEPA asked the US Army Corps of

Engineers (USACE) to perform additional studies to

- better evaluate the engineering feasibility of dredging as a cleanup alternative. This study is a joint

effort of the US Army Engineer Division, New England,

Waltham, Mass., and the US Army Engineer Waterways

Experiment Station (WES), Vicksburg, Miss. This paper

describes a proposed pilot study of dredging and

dredged material disposal alternatives to support the

engineering feasibility study. This study would be a

small-scale field test of several dredging and disposal techniques carried out onsite between December

1987 and June 1988. The study will evaluate three

types of hydraulic dredge and two disposal methods.

The pilot study will be extensively monitored, in

order to obtain sufficient data to support the technical objectives of the pilot study and to ensure that

both public health and the environment are protected.

Pilot study operations will be modified or stopped if

significant increases in the level of contaminants are

detected at the Coggeshall Street Bridge.

INTRODUCTION

Site Description

New Bedford Harbor, a tidal estuary, is situited between the city of New

Bedford cn the west and the towns of Fairhaven and Acushnet on the east at the

head of Buzzards Bay, Massachusetts. The site can be divided into two geographic areas. The most northern portion of the site extends from the

167 92-16020

1111111li111 lIIlllllt 11 l~ l~t111111
Coggeshall Street Bridge north to Wood Street in Acushnet. The remainder of

the site extends south from the Coggeshall Street Bridge through the New Bedford Hurricane Barrier and into Buzzards Bay. Geographic boundaries include

the shoreline, wetlands, and peripheral upland areas.

PCB contamination in New Bedford was first documented by both academic

researchers and the Federal Government between the years 1974 and 1976. Since

the initial survey of the New Bedford area, a much better understanding of the

extent of PCB contamination has been gained. The entire area north of the

Hurricane Barrier, 985 acres, is underlain by sediments containing elevated

levels of PCBs and heavy metals, including copper, chromium, zinc, and lead.

PCB concentrations range from a few parts per million to over 100,000 ppm.

Portions of western Buzzards Bay sediments are also contaminated, with concentrations occasionally exceeding 50 ppm. The water column in New Bedford Harbor has been measured to contain PCBs in the parts per billion range.

Background Information

In August 1984, the USEPA published a Feasibility Study of Remedial

Action Alternatives for the Upper Acushnet River Estuary above the Coggeshall

Street Bridge. Sediments from this area of the New Bedford Harbor Superfund

Project contain much greater PCB concentrations than the remainder of the harbor. The study proposed five alternatives for cleanup of the contaminated

sediment. Four of these alternatives dealt specifically with dredging the

estuary to remove the contaminated bottom sediments. Disposal options included an intertidal disposal site, partially lined for one option and fully

lined for a second, disposal in an upland site, and disposal in cells constructed in the estuary and covered with clean material.

Public and interagency comment on these dredging and disposal alternatives prompted the USEPA to ask the USACE to perform additional predesign

studies for dredging and disposal alternatives to develop the technical information necessary to evaluate the engineering feasibility of these alternatives. The Engineering Feasibility Study (EFS) began in October 1985 and is

scheduled to be completed in March 1988. It addresses two questions:

(a) what are contaminant release rates from dredged material disposal alternatives, and (b) what are contaminant release rates from dredging alternatives?

The technical approach used in the EFS to evaluate disposal alternatives

is based on strategy outlined in a USACE publication.* This strategy incorporates findings of research conducted by the USACE, USEPA, and others over

the past 10 years, and on worldwide experience in managing dredged material

disposal. It consists of a suite of tests developed specifically for the

unique nature of dredged material that, when applied to New Bedford Harbor

sediment, will allow for site-specific evaluation and conceptual design of

available disposal alternatives.

The other part of the question for the EFS is evaluation of dredging alternatives, i.e., can the contaminated sedivent be effectively removed from

* Francingues, N. R., et al. 1985. "Management Strategy for Disposal of

Dredged Material: Contaminant Testing and Controls," Miscellaneous Paper

D-85-I, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

168
the estuary by conventional or specialty dredging equipment without unacceptable migration of contaminants to the environment? Unlike the disposal issue,

testing protocols and a prescribed strategy have not been developed for estimating contaminant release from a dredging operation itself. The EFS addresses the questions of sediment resuspension and contaminant migration during the dredging operation by reviewing past studies of dredging projects,

characterizing the hydraulic conditions in the Upper Estuary, performing flume

tests to physically model sediment deposition and resuspension, estimating

contaminants associated with suspended sediment based on limited laboratory

tests, and incorporating the results into a numerical sediment migration

analysis.

Much of the information needed to evaluate the design of proposed dredging and disposal alternatives for the New Bedford Harbor Superfund Site (above

the Coggeshall Street Bridge) can and will be provided by the EFS. This information will be critical to the record of decision (ROD) for selection of

the remedial action alternative. However, the EFS approach uses laboratory

(bench-scale) studies, literature reviews, and desktop analyses to assess engineering feasibility and to develop conceptual designs. The sound engineering approach for evaluation of alternatives and verification of design

parameters is to perform pilot-scale evaluations after laboratory studies and

before final selection and design of a prototype system. This is particularly

true for the New Bedford Project where dredging and disposal of highly contaminated sediment must be considered innovative application of alternatives,

where dredging equipment must be evaluated without benefit of field-verified

laboratory testing protocols, and where a data base on the impact of sitespecific factors on design is currently not available. A pilot study will reduce the uncertainty in the choice of alternatives for the ROD and in the

final design and will allow smoother transition from alternative selection to

final design and thence to construction. For these reasons, the USEPA and the

USACE are proposing that a pilot study be performed at New Bedford to evaluate

proposed dredging and disposal alternatives in the field.

Study Objectives

The pilot study will provide the opportunity to evaluate different

dredges, dredge operating procedures, disposal methods, and control techniques

under site-specific conditions of New Bedford Harbor. The information gathered during the pilot study will improve our ability to address the critical

issues being evaluated by the EFS. Listed below are the specific technical

objectives of the pilot study.

a. Determine the efficiency of dredging for removal of PCB-contaminated

sediment from New Bedford Harbor.

b. Evaluate actual sediment resuspension and contaminant release during

field conditions for selected dredging equipment, operational controls, and turbidity containment techniques.

c. Refine and scale-up laboratory data for design of disposal/treatment

processes for contaminated dredged material from the site.

169
d. Develop and field test procedures for construction of contained

aquatic disposal (CAD) cells for contaminated dredged material under

site-specific conditions.

e. Evaluate containment of PCBs in diked disposal areas and CAD cells

filled with contaminated dredged material.

f. Assess solidification techniques for contaminated dredged material

with respect to implementability.

•. Establish actual cost data for dredging and disposal of New Bedford

Harbor sediment.

Additional Benefits

Conduct of the proposed study would result in related benefits, as described below.

a. Construction techniques for the confined disposal facility (CDF) and

the CAD can be tested in the field for site-specific conditions.

b. Information on air emissions during dredging and disposal can be

evaluated.

c. Other regulatory agencies and the public will become more involved in

seeking a solution for cleanup of the site. Requirements for complying with other environmental laws and regulations will be addressed

early on and allow smoother review and approval for the final cleanup

action.

d. Experience gained with the pilot study will expand information on

dredging and disposal alternatives and benefit evaluation of remedial

action alternatives for the lower harbor as well as the upper

estuary.

e. The pilot study will reduce uncertainty in the ROD for selection of

the final alternative by showing that dredging will or will not cause

major environmental consequences. Without the pilot and the sitespecific evaluation it provides, the project could, at a tremendous

cost, proceed through final design, contract award, contractor mobilization, and initial construction only to be stopped because of unforeseen, undocumented adverse environmental impacts.

PILOT STUDY DREDGING AND DISPOSAL OPERATIONS

Project Description

The pilot study will involve the evaluation of three types of hydraulic

dredges and two disposal methods. Approximately 15,000 yd 3 of material will

be removed and disposed of during the study. Approximately 7,500 yd3 is contaminated sediment, with PCB levels in the 100-ppm range. The dredging and

disposal process involves placing the contaminated sediment in the-bottom of

the disposal site and then capping it with a layer of clean sediment.

170
A confined disposal facility and confined aquatic disposal will be evaluated during the study. These disposal methods are described in detail later

in this section. Both disposal sites are located within the boundaries of the

Superfund Site.

An extensive monitoring program will be implemented to detect any contaminant releases during pilot study operations. This program is designed to

obtain data to support the technical objectives of the study and to ensure

that public health and the environment are protected.

Study Site

Dredging and disposal operations will be conducted in and adjacent to a

small cove located just north of the Coggeshall Street Bridge on the New Bedford side of the Acushnet River. The general area is shown in Figure 1, with

the dredging and disposal areas shown in Figure 2. Water depths in the cove

are approximately 0.5 ft at mean low water (mlw), and the mean tide range is

3.7 ft with the spring range being 4.6 ft. Tidal currents within the cove are

negligible.

Description of Dredged Material

Two dredging areas will be located in the cove. Approximately 10,000 yd 3

of material will be removed from area I and 5,000 yd 3 from area 2 (see Figure 2). Material from area 1 will be placed in the CDF. Area 1 will then be

used as the CAD site and will receive the material from area 2.

Thirteen sediment cores and seven grab surface samples have been taken

from within the cove. The top 2 ft of each core was analyzed for PCBs. Levels in the 0- to 12-in. horizon ranged from 250 to 1.70 ppm. The PCB levels

in the 12- to 24-in. horizon ranged from 105 ppm down to the detection limit.

The seven grab samples, which consist of the top 6 in. of material, were

combined to form a composite sample; standard and modified elutriate tests

were performed on this material. Additional core samples will be taken from

the dredging areas prior to the start of work. The number of cores and type

of analyses are described in the section on the monitoring program.

Dredging Equipment

Three hydraulic dredges will be used during the pilot study: a hydraulic

pipeline cutterhead dredge, a horizontal auger dredge known as a Mudcat, and

the hydraulic pipeline dredge with a special attachment called a Matchbox.

These hydraulic dredges operate on the principle of the centrifugal water

pump. A vacuum is created on the intake side of the pump, and the atmospheric

pressure forces water and sediments through the suction pipe. The dredged

materials are then hydraulically pumped via pipeline to the disposal site in a

slurry consisting of 10 to 40 percent solids.

These three pieces of equipment were selected based on their performance

in the following critical areas:

a. They will be able to efficiently and effectively remove the layer of

contaminated sediment.

171
Street S~~~~~~Wood Bridge .... •% - '

-- Pilot Study Site "

•'- .• /

, oggeshall Street Bridge

WT•

---- - ,.b .. ...

, O* \ "T.. ---

41ur Do*. Ne e f rd ar e orpe o s tu~d y a e

I'd2
Building

250eg

Dredging Confined Aquatic

250j Area 1 Disposal Area (CAD) s

q 180' curtainr,

SDredging oii

1 8 0 1 Area 2

LW:

Disposal Facility { iewll 8nk

Dichrg fomCD

soot 0.0T

Top of bank

scale 1" = 200' elevation

Datum: Mean Low Water

Figure 2. Dredging and disposal areas, New Bedford Harbor pilot study

173
b. They will minimize the resuspension of sediment while operating.

c. They will be able to operate in the shallow water that is prevalent

in the Upper Estuary.

Confined Disposal Facility

A physical description of the CDF is provided by the tabulation below.

Parameter Value

Area of site 250,000 ft 2

Area of site currently below high-water line 125,000 ft 2

Top elevation of dike +12 mlw

Top elevation of dredged material +8 mlw

Surface area at elevation +8 mlw

Primary cell 145,000 ft 2

Secondary cell 32,500 ft 2

Quantity of material excavated from site 17,500 yd3

Quantity of dredged material to be placed in site 10,000 yd 3

Quantity of dike material 24,500 yd3

Site Construction

Approximately 24,500 yd 3 material will be used in constructing the

1,700 ft of dike that surrounds the site, 700 ft of which is located below the

high-water line. This 700-ft-long section of dike will be constructed on a

geotechnical fabric due to poor foundation conditions. The fabric is installed by placing it on the existing bottom along the dike alignment. Granular fill is then added in 2-ft lifts. Some bottom material will be displaced

and resuspended during the construction process; however, the quantity is expected to be small when compared with other pilot study operations. The monitoring program will be ongoing during this phase of the project, and a silt

curtain will be in place around the site to contain any sediment that may be

resuspended.

The construction of the CDF will also require the excavation of the upland portion of the site where existing elevations vary between +6 and

+10 mlw. This area will be excavated to elevation +5.0 mlw, requiring the

removal of approximately 17,500 yd 3 of material. This material will be tested

for the presence of PCBs, metals, and volatiles, as well as suitability for

use in dike construction. It is anticipated that some of the material can be

used in dike construction. The remaining clean material would be used in reconstructing the athletic field with approximately 5,000 yd 3 being stockpiled

onsite and used as an additional cap for the CDF site.

Material to be used in dike construction would be brought to the site by

truck. Trucks should average 30 round trips per day during January, February,

and March 1988. The choice of truck routes will be coordinated with the city

of New Bedford to minimize impacts to the surrounding neighborhoods. Traffic

control features such as signs, police, and flagmen will be used throughout

the work period.

174
Site Operation

The CDF is divided into a primary and secondary cell. The dredged material enters the primary cell in a slurry consisting of 10 to 40 percent solids. The slurry will be discharged through the submerged diffuser, which will

be attached to the end of the dredge pipeline. This device is designed to release the slurry parallel to the bottom of the site and at a reduced velocity.

Here the solids are allowed to settle out, and the excess water flows over a

weir into the secondary cell. The primary cell has the capacity to hold approximately 25,000 yd 3 of slurry. It is estimated that only 20,000 yd 3 of

slurry will be produced in removing the 5,000 yd 3 of contaminated sediment

from dredging area 1; therefore, it is possible to retain all slurry in the

primary cell until all the contaminated sediment has been removed. This mode

of operation will not provide the desired estimate of effluent quality for

prototype facilities under typical operating conditions. Therefore, an

adjustable-height weir will be lowered to allow overflow into the secondary

cell, so that monitoring can be done during the latter stages'of contaminated

sediment dredging.

The excess water will be mixed with cationic polymer emulsions (Magnifloc

1586C, Nalco 7126, or similar) as it enters the secondary cell. Tests performed for the EFS indicate that as much as 82-percent additional suspended

solids reduction can be achieved in the secondary cell following polymer flocculation. The secondary cell fills with water until elevation +9.0 mlw is

reached; then it flows over another weir structure back into the cove. It is

estimated that an effluent suspended solids concentration of 70 mg/i can be

attained. A small portion (10 to 50 gal/min) of the water leaving the secondary cell will receive additional treatment. A pilot-scale filtration and carbon absorption system will be employed to evaluate the feasibility of this

type of treatment.

Approximately 5,000 yd 3 of contaminated sediment will have been placed in

the site initially. This material is the top 2 ft of sediment from dredfing

area 1. This material will have been capped with an additional 5,000 yd of

clean sediment taken from the 2- to 6-ft layer of dredging area 1.

It is estimated that a 1-ft layer of material with a sludgelike consistency will be present in the secondary chamber at the completion of dredging.

We plan to solidify this material in place by mixing it with portland cement

to demonstrate application of in situ stabilization. This process will hydrate or lock in the pore water.

Contaminant release from the CDF discharge during dredging operations is

calculated directly from the dredge flow rate, settling test data, and the

suspended sediment contaminant concentrations and dissolved contaminant concentrations observed in the modified elutriate test.

The CDF is being constructed on property owned by the city of New Bedford. The USEPA will lease the property from the city until a final decision

is made regarding cleanup of the Superfund Site. The CDF is a temporary facility that may be left in place, removed, or incorporated into the overall

cleanup plan that is eventually chosen for the Superfund Site.

175
The remaining sections of the city property adjacent to the CDF will be

modified during the construction process. During the pilot study and for the

duration of the lease, the site will be fenced off and constantly monitored.

The USEPA will be responsible for maintenance and repairs to the facility.

The site will be capped with an additional layer of material in either late

fall 1988 or spring 1989. This additional cap material will be obtained from

the dikes surrounding the site, material stockpiled onsite, and from offsite.

Confined Aquatic Disposal

Site Construction

The CAD cell (dimensions, 250 by 250 ft; bottom elevation, approximately

-6.5 mlw) will be created at dredging area 1 during the dredging that provides

the material for the CDF.

Site Operation

Approximately 2,500 yd 3 of contaminated sediment from the top 2 ft of

dredging area 2 will be placed along the bottom of the CAD cell. The material

will be discharged through the submerged diffuser. The contaminated sediment

will be placed in a 2-ft layer and then capped by a 2-ft layer of clean material removed from the 2- to 4-ft layer of dredging area 2.

Controls During Operations

Pilot study operations will be halted during severe weather conditions.

Additional controls that can be implemented during the various phases of the

study are discussed in the following paragraphs.

Construction of CDF

A silt curtain will be deployed around the work area during the construction of the dike section located in the water. As an additional control, work

could be restricted to the flood tide. Such a restriction would be imposed if

monitoring detected elevated levels of contaminants during the operation.

Dredging and CAD

All dredging and disposal into the CAD cell will take place within the

cove, as shown in Figure 2. The discharge from the CDF will also be within

the cove. A silt curtain and oil boom will be deployed across the mouth of

the cove during the entire operation (Figure 2). An additional control that

will be implemented if needed involves restricting the various operations to

flood tide periods. Additional downtime could also be provided between operational periods (intermittent operations). The operation of the dredges can

also be modified. The depth of cut, rotation of cutterhead, and swing speed

of the dredge ladder can all be reduced on the cutterhead dredge. The depth

of cut, rotation of horizontal auger, and rate of advance can all be reduced

on the Mudcat.

176
The need to implement any of these operational controls will be determined by the monitoring that is ongoing during all phases of the project. Decision criteria, which are described later, will be used to evaluate the need

for additional controls.

MONITORING PROGRAM

Objective

This monitoring program was designed by personnel from the WES and the

USEPA's Environmental Research Laboratory, Narragansett (ERLN), Rhode Island.

The objective of the monitoring program is to provide information that can be

used to (a) evaluate the effectiveness of the dredging and disposal techniques

employed, (b) predict the magnitude and areal extent of water quality impacts

during a full-scale operation, (c) select optimum monitoring protocols, and

(d) regulate pilot study operations. Results of this program will be used to

evaluate the risks and potential benefits of a full-scale dredging and disposal operation relative to other proposed options for decreasing the contamination effects of PCBs and metals in New Bedford Harbor.

The level of effort described in this section is meant to acquire

sufficient data to meet the four objectives listed above. However, the

program is intended to be flexible. Monitoring of certain activities can be

expanded if initial results indicate such a need. The program includes

physical, chemical, and biological evaluations of sediment, harbor water,

effluent from the CDF, and leachate from the CDF. Air monitoring is not

addressed in this section. The ERLN has designed the biological monitoring

that will be performed during the pilot study.

Program Description

The monitoring program is divided into four major tasks associated with

evaluating impacts and measuring the success of the pilot project. Each of

these tasks has two or more subtasks, as outlined below.

a. Preliminary sampling

(1) Water quality characterization

(2) Sediment characterization

b. Evaluation of the CDF

(1) Effluent water quality

(a) During active filling

(b) Storm runoff, postfilling

(2) Leachate water quality

c. Evaluation of CAD

(1) Disposal into CAD cell

177
(2) Contaminant migration

d. Evaluation of dredge types/disposal techniques

(1) Removal efficiency

(2) Comparison of dredge types/disposal techniques

(a) Plume extent

(b) Far-field water quality

Preliminary Sampling

Preliminary sampling will be used to refine the proposed techniques for

this specific project area and to determine the natural range of specified

physical, chemical, and biological response variables that occur within the

system. Data will also be collected to verify results of certain predictive

tests or models (e.g., settling tests, elutriate tests, and plume behavior).

Water Quality Characterization

The basic sample component for water quality assessments will be hourly

water samples taken over one tidal cycle and pooled into ebb and flood composites. Samples will be taken on five sample dates at four stations (see Figure 3) and will be opportunistically chosen for normal and worst-case

conditions (e.g., spring tide-high discharge, storms). The Coggeshall Street

Bridge station is the focal point relative to the decision criteria. At this

station, stream discharge will be measured for each sampling event, and samples will be composited proportional to flow from two cross-sectional subareas

and three water depths. Samples from the other stations will be taken at

three depths where conditions allow. A sampling event will consist of ebb and

flood composites of hourly samples at each station. These samples will be

analyzed for:

a. Suspended solids.

b. Temperature.

c. Salinity.

d. Whole water PCB (total, aroclors, congeners).

e. Metals on 50 percent of samples (cadmium, copper, lead).

f. Total organic carbon (TOC) on 10 percent of samples.

•. Filterable PCB (total, aroclors, congeners) and metals on 25 percent

of samples.

Biological testing during this preliminary phase will include the following tests. A description of these tests is also provided.

178
Nood Street Bridge,*-.. ' a ...

D P l .

S• Pilot Study Site

C geshalll Street Bridge

SR H A =

O\ 4 40- "

SCALE S•,0 1000 2000 3000 4000 Feet

S( Monitoring Station

Figure 3. Sampling stations for pilot study

179
a. Sperm cell test on all samples.

b. Sperm cell and physical/chemical tests on noncomposited hourly samples on two sample dates at Coggeshall Street station

(2 x 6 x 2 = 24).

c. Two- and seven-day tests on expected worst-case and expected normal

conditions.

d. Mussel deployments for worst and normal, sampled on days 0, 3, and

28.

The mussel has been demonstrated to be a reasonable biological monitor

whose sensitivity to chronic impact makes it an effective early warning system

for other biological components of the marine ecosystem. Prior to construction and at the initiation of each subsequent phase of the pilot study, mussels will be transplanted to four stations (see Figure 3). Tissues will be

analyzed chemically on mussels collected for transplants at time zero. Collections will be made 3 days following the initiation of each phase of the

pilot study, with the mussel tissue being chemically analyzed. The first biological measures (mortality, actual growth, scope fcr growth) will be made on

mussels collected at day 7. Both chemical tissue analyses and biological indicators will be measured after 28 days of exposure.

As shown in Figure 3, four caged mussel stations will be established:

three in the transect from Coggeshall Street Bridge to the Acushnet River side

of the hurricane barrier and a control station in Buzzards Bay. Four replicates will be taken per station, with the number of individuals per replicate

as identified below.

a. Scope for growth: 10/cage.

b. Growth and survival (marked and measured individuals): 10/cage.

c. Bioaccumulation: 30/cage.

d. Total: 50/cage.

e. Redundancy: 50/cage.

The sea urchin (Arbacia punctulata) sperm cell toxicity test is a proven,

effective, indicator of ambient water toxicity. This test provides rapid estimates of toxicity. It will be used to evaluate the toxicity of various ambient waters north of the Coggeshall Street Bridge throughout the study and the

effluents from the CDF.

Whole (undiluted) receiving waters will be tested from each site. Discharge waters from the CDF will be tested as an effluent. There will be five

experimental concentrations (diluted with site control water).

Three replicates will be tested for each receiving water sample or effluent concentration. Two controls will be selected for each test series: a

site control (clean seawater collected at the south end of West Island, Massachusetts) and a Narragansett Bay seawater control.

180
The 2-day red algae (Chcampa parvula) reproductive test, the 7-day mysid

(Mysidopsis bahia) reproductive, growth, and survival test, and the 7-day

sheeps head minnow (Cyprinoden variegatus) growth and survival test will be

conducted during the pilot study to evaluate toxicity in the receiving waters

or the effluent discharge from the CDF.

Whole (undiluted) receiving waters will be tested from each site. Discharge waters from the CDF will be tested as an effluent. There will be five

experimental concentrations (diluted with site control water).

A minimum of two replicates will be provided for the algal tests, and

three for the fish tests. A minimum of eight replicates will be used for the

mysid reproductive tests. Five plants, 15 fish, and 5 mysids will be used in

each replicate.

Two controls will be selected for each test series: a site control

(clean seawater collected at the south end of West Island, Massachusetts) and

a Narragansett Bay seawater control.

Sediment Characterization

Six sediment cores will be taken to a depth of 6 ft below the surface

from each area to be dredged. These cores will be split into samples representing six horizons (0-0.5 ft, 0.5-1.0 ft, 1.0-1.5 ft, 1.5-2.0 ft,

2.0-2.5 ft, and 2.5-3.0 ft) (6 cores x 6 horizons x 2 areas to be dredged

= 72). This is being done to determine the depth at which clean material is

found. Physical and chemical parameters to be measured on these samples

include:

a. Water content, specific gravity.

b. Atterberg limits, grain size.

c. PCBs (aroclors, congeners), TOC.

d. Metals (cadium, copper, lead, chromium, and selected others) (one

core per site on <64-p fraction).

e. Elutriate tests on composites (standard and modified).

Biological tests will include the Ampeiisca toxicity test on whole sediments and sperm cell tests on water from the Ampelisca test.

The tube-dwelling amphipod Ampelisca abdita will be used to evaluate sediment contamination. This organism has been shown to be sensitive to contaminated fine-grained sediments. The toxic response will be mortality and

emergence. The replication scheme will be: three chambers per treatment,

with 30 Ampelisca per chamber. The control sediment will be the relatively

uncontaminated sediment from Central Long Island Sound.

For each dredging area, one sample will be composited by depths of 0 to

1, 1 to 2, and 2 to 4 ft. A modified elutriate test will be run on each sample to predict effluent quality from the CDF. A standard elutriate test will

be run on each sample to predict soluble contaminant release from the CAD

181
construction and the dredging operation. Each elutriate test will be run in

triplicate. Makeup water for the elutriate tests should be collected from the

Upper Acushnet River Estuary.

Evaluation of the CDF

The confined disposal facility will be evaluated for (a) the effects of

different treatment techniques on the concentration of contaminants in the

effluent and (b) the long-term migration of contaminants within the leachate.

Effluent treatment techniques will be evaluated relative to one another and to

water quality standards and existing water quality conditions. Effects during

construction of the CDF are addressed in task 4 under operational evaluations.

The format used in the following sections consists of a statement of the

question being addressed, followed by the appropriate null hypothesis. A sampling program designed to test each null hypothesis is then detailed along

with recommended numbers of samples, stations, and statistical analyses.

Effluent Water Quality

During Active Filling

The question to be answered is: Are techniques available that can be

used to reduce contaminant concentrations in effluent from a CDF into which

contaminated New Bedford Harbor sediment is disposed? (Secondarily, are

observed treatment levels substantially different and economically practicable

to justify full-scale application of these techniques?)

The null hypothesis is: The concentration of specific contaminants in

the effluent and the toxicity of effluent from the CDF will be unchanged by

the treatment method.

The CDF effluent will be treated by dividing the CDF into two cells, with

primary settling in the first cell and chemically assisted clarification in

the second cell. Effluent quality will be evaluated by chemically analyzing

both filtered and unfiltered effluent to determine contaminant loadings in the

suspended and dissolved phases. Relative toxicity of treated effluents will

also be determined using bioassay techniques.

Effluent contaminant concentrations will be analyzed for the following

treatments:

182
Data To Be

Treatment Collected*

Primary cell - initial filling phase 1,2

Primary cell - late filling phase 1,2

Secondary cell - initial filling phase 2

Secondary cell- late filling phase 2,3

Filtered 2

Carbon-treated 2

* Data types are:

I = Suspended solids only - 24 hourly samples for 5 days.

2 = Ten 24-hr composites of suspended solids, whole water and

filterable PCBs, metals on 50 percent of samples, TOC on

10 percent of samples, and sperm cell test on subset (some on

chemically fractionated samples).

3 = Most sensitive of 2- and 7-day tests on final effluent.

Mean contaminant concentrations in the effluent and the toxicological

response will be compared by treatment using analysis of variance (ANOVA).

Effluent Water Quality -

Storm Runcff Postfilling

The question to be addressed is: What are the concentrations of any contaminants released to stormwater runoff?

The null hypothesis is: Contaminant concentrations in stormwater runoff

are not elevated.

Following completion of disposal into the CDF and initial dewatering,

effluent quality during storm runoff conditions will be determined. During a

storm event, effluent samples will be collected hourly until flow has peaked.

For 10 of these samples, determinations will be made of suspended solids, PCBs

(whole water and filterable), pH, salinity, and temperature. These data will

be used to predict performance and effectiveness of the CDF for sequestering

contaminants.

Leachate Water Quality

The question is: What are the concentrations of any contaminants released to the leachate?

The null hypothesis is: Contaminant concentrations in leachate are similar to local ground water and do not increase with time.

Seven monitoring wells will be installed in and around the CDF (see Figure 4). These will be sampled for background contaminant concentrations before dredged material is placed in the site. The wells will also be sampled

periodically over the life of the CDF. Undisturbed core samples of dredged

material will be taken from the CDF and the pore water analyzed.

183
CDF Discharge

GO

secondary 3

settling

0

primary settling

A 0 0 3M

0 /

0 MONITORING WELL

13SEDIMENT CORE

BE D E EL +12.0

A maximum water level _ S~maximum sediment level

C3

= 5.• •GN EL 7 .6-_•v *.~

> 0.

Uj screening heet pile wall

depth

Note: Exact screening depths to be determined

during well drilling.

Figure 4. Confined disposal facility

184
The monitoring wells will be sampled and the filtered samples will be

analyzed at least three times prior to dredging. One sample will be taken

immediately prior to initiating dredging. Samples from the wells will be collected three times per week while the CDF is being filled and weekly for the

first month after the CDF is filled. Six of the samples collected during that

time period will be analyzed for PCBs, TOC (10 percent of samples), pH, salinity, and metals (50 percent of samples). The remainder of the samples will be

archived and analyzed, if necessary, to characterize rapid changes in groundwater quality. The wells will continue to be sampled quarterly for 2 years.

In addition to the monitoring wells, sediment cores will be taken from

the sediment in the CDF according to a pattern similar to that shown in Figure 4. Sediment and pore water from these cores will be characterized chemically and physically, to include PCBs, selected heavy metals, and water content. These cores will be collected after initial consolidation of the filled

CDF and after drainage of free water from the surface of the CDF.

Mean contaminant concentrations by well and sampling date will be analyzed using ANOVA.

Evaluation of CAD

CAD will be evaluated for the ability of the operation to place a contaminated layer of material in the bottom of the excavated cell and cap this contaminated layer with a layer of clean material. Upward migration of

contaminants within the completed CAD cell will be assessed by analyzing contaminant concentrations in sediment horizons approximately 50 and 400 days

following CAD cell construction.

Disposal Into the CAD Cell

The evaluation will address the following question: Can contaminated

sediment be isolated by excavating a disposal cell, filling the bottom half

with the contaminated material, and filling the top half with a layer of clean

material?

The null hypothesis is: Contaminants in the bottom layer of sediment in

the completed CAD are greater than those in the cap material and similar to

contaminant concentrations measured in surface (0 to 50 cm) sediments before

dredging.

Sediment core samples will be taken in the area to be dredged before construction and at the CAD site following construction and initial consolidation. The cores will be divided into sediment horizons, and each horizon will

be analyzed for contaminant concentrations and toxicological response.

The following samples will be taken:

a. Predredging: One hundred 2-ft cores composited to 20 (taken to characterize contaminant concentrations of the material to be dredged).

b. Post-CAD construction (-50 days postconstruction): One hundred 5-ft

cores divided into 6-in. horizons and composited to 20 samples per

horizon.

185
Each sample will be analyzed for PCBs, metals, and Ampelisca toxicity.

Mean contaminant concentrations by location will be analyzed using ANOVA.

Contaminant Migration

The question is: Following construction of the CAD cell, will contaminants from the contaminated bottom layer be transported up into the cleaner

cap layer?

The null hypothesis is: Contaminant and toxicological response levels of

sediment horizons down through the CAD remain unchanged through time.

Sediment core samples will be taken in the CAD site approximately I year

following construction. The cores will be divided into sediment horizons, and

each horizon will be analyzed chemically and toxicologically for contaminant

concentrations. Results of this subtask will be compared with those of the

50-day samples taken in the previous subtask.

Approximately 400 days postconstruction, one hundred 5-ft core samples

will be taken, divided into 6-in. horizons, and composited to 20 samples per

horizon. Each sample will be analyzed for PCBs, metals, and Ampelisca

toxicity.

Mean contaminant concentrations and toxic response by horizon and date

(50 days versus 400 days postconstruction) will be analyzed using ANOVA.

Evaluation of Dredge

Types/Disposal Techniques

Each type of dredging equipment and each disposal technique (CAD versus

CDF versus no dredging) could behave differently with respect to its effects

on water quality during construction and operation. Additionally, the effectiveness of each dredge type may be different with respect to its ability to

remove primarily contaminated sediment without substantial overdredging.

Studies carried out in this task will assist in determining whether any equipment or technique should be preferred because of greater efficiency or relatively low water quality impacts.

Removal Efficiency

The question to be addressed is: Can optimum dredging depth be predicted

and controlled with sufficient accuracy to remove the entire contaminated

layer from a dredging area? What amount of overdredging is necessary to meet

this goal?

The null hypothesis is: Contaminant levels in sediment cores taken from

the dredging area following dredging are the same as levels before dredging.

Sediment core samples will be taken in the dredging area immediately before and following the final dredge pass predicted to reach uncontaminated

sediment. If substantial contaminated material still remains in the dredging

area, a deeper dredge cut will be made and the area retested until contaminant

levels similar to reference levels are attained.

186
Sampling will be designed to collect ten 3-in. cores from the dredging

area and analyze (within hours) for total PCBs.

Mean contaminant concentrations between sets of sediment cores will be

analyzed using ANOVA.

Plume Extent

The question to be addressed is: Are any tested dredge types or disposal

techniques preferred because of their ability to minimize water column suspended sediment plumes?

The null hypothesis is: Suspended sediment plumes are similar for each

dredging or disposal activity.

During operation of the three different dredge types and during disposal

into the CAD cell, the development and extent of plumes will be determined

with suspended sediment samples.

A longitudinal transect will be established extending downcurrent of the

dredge or CAD cell. Samples should be taken along this transect in the center

of the plume at distances of 50, 100, 400, and 800 ft from the dredge, as well

as on either side of the silt curtain. Twelve additional sampling stations

will be located along three perpendicular transects, as shown in Figure 5.

Current measurements will be taken frequently. If water current magnitudes

are not sufficient to move the plume in one general direction, a uniform sampling grid (Figure 5) will be used. Sampling should stop when the limit of

the plume is reached, except that one additional sample should be taken outside the plume. Plume sampling will be executed for at least three events for

each type of dredging equipment. Discrete samples should be taken at hourly,

or more frequent, intervals at middepth during the time period that the dredge

is operating. The duration of sampling should avoid periods when dispersion

of the plume will be interrupted by the silt curtain. Therefore, sampling

will begin soon after the dredge starts on a given day. Samples will be analyzed for suspended solids, PCBs, and metals (50 percent of samples only). In

addition, a transmissometer will be towed outside the silt curtain at hourly

intervals. Sampling stations will be located using electronic positioning

equipment.

Measurements will be taken of plumes produced by the following

activities:

a. Dredge type 1.

b. Dredge type 2.

c. Dredge type 3.

d. Disposal into CAD cell.

The following information will be recorded for each type of dredge:

position of dredge, depth of water, pump power, pumping rate, slurry concentration, depth of cut, width of cut, speed of forward progress, and where appropriate, cutterhead swing speed and rotation rate.

187
* CIRRENT

* * •LEGEND

0 point of dredging S• sample location

SCALE

200 0 200 400 ft

a. In the presence of significant current velocities

b. In the absence of significant current velocities

Figure 5. Plume sampling plans

188
An appropriate dredge head sampling apparatus will be installed on each

of the dredges used. Selected samples from the dredge head will be analyzed

for suspended solids, PCBs, and metals. These samples will be selected to

represent differing dredging techniques and operating conditions and will be

composited over an operating day.

Analysis of plume data will yield a qualitative description of plume geometry and a quantitative measure of the rate of sediment resuspension from

the dredge head. Sediment and contaminant concentration isopleths will be

constructed to show the horizontal distribution of the sediment plume caused

by each dredge type and operation technique. If current velocities are sufficient to transport the plume downcurrent, the product of the current velocity and the sediment and contaminant concentration distribution in a cross

section of the plume will be used to calculate a mass flux rate. This mass

flux rate can be used to calculate the rate of sediment and contaminant resuspension from the dredge. A correlation between dredge operation variables and

the rate of sediment and contaminant resuspension will aid in specifying

dredging methods to minimize contaminant release during dredging.

Far-Field Water Quality

The question to be addressed is: Are any pieces of dredging equipment or

disposal techniques preferred because of their ability to minimize far-field

water column suspended sediment and toxicological impacts?

The null hypothesis is: Suspended sediment, dissolved and particulate

contaminant concentrations, and toxicological response are similar by station

for each piece of equipment or technique used and are similar to reference

conditions.

Samples will be taken at four stations (Figure 3). Stations were selected based on the predicted extent of the plume. Sampling will occur during

both operational and nonoperational periods. Nonoperational periods, both

planned and those that occur as a result of delays, will be used as reference

conditions. There is no adequate spatial reference that can be sampled simultaneously, and the use of sampling either before or after the project as a

reference would incorporate unknown seasonal influences that could be factored

out only with years of data.

The operations to be tested are:

a. Nonoperational (immediately before and after the project and between

each construction phase).

b. CDF dike construction.

c. Dredge type 1.

d. Dredge type 2.

e. Dredge type 3.

f. Disposal into CAD cell.

189
As discussed with regard to preliminary sampling, the Coggeshall Street

Bridge station is the focal point relative to the decision criteria. A sampling event will consist of ebb and flood composites of hourly samples at each

station following the same procedure described under preliminary sampling.

These composite samples will be analyzed for the following:

a. Suspended solids.

b. Temperature.

c. Salinity.

d. Whole water PCB (total, aroclors, congeners).

e. Metals on 50 percent of samples.

f. TOC on 10 percent of samples.

•. Filterable PCBs (total, aroclors, congeners) and metals on

25 percent.

Toxicological tests on these samples will include:

a. Sperm cell test on all samples.

b. Two- and seven-day tests:

(1) Once during CDF construction.

(2) Three times during filling of CDF.

(3) Once during disposal into the CAD cell.

(4) Twice following project completion.

c. Mussel deployment at each station:

(1) Once during CDF construction.

(2) Once during CDF filling.

(3) Three-day sample for each dredge type and nonoperational period.

(4) Once during disposal into the CAD cell.

(5) Twice following project completion (spring-dry, spring-wet).

Mean suspended solid concentrations, dissolved contaminant concentrations, and toxicological response between dredging operations will be analyzed

using ANOVA.

190
Supporting Data Collections

Several data sets will also be collected to assist in interpretation of

study results. These will include rainfall and wind velocity and direction,

tidal gage measurement, and freshwater discharge.

Sequence of Monitoring Events

The sequence of events is described below. However, it should be noted

that the actual sampling will likely be somewhat different because of unknown

factors, such as equipment breakdowns.

The preliminary sampling will consist of five events, as described

earlier. Two events took place in July 1987 and the remaining three will be

carried out in late September and early October 1987.

Construction of the section of the CDF located below the high-water line

will extend over approximately a 6-week period. The critical period is at the

start of the operation when the geotechnical fabric and the initial lifts of

fill will be put in place. The first sampling event will take place 3 days

prior to the start of work. Sampling will continue for the first 4 days of

the operation. Five sampling events will take place during the construction

period when work is not going on. A sampling event will take place once a

week for 5 weeks during the remainder of the operation.

It is anticipated that each dredge will operate for a 3- to 5-day period

in the contaminated sediment with a 5-day shutdown period between work

periods. A sampling event would be carried out 3 days prior to the start of

dredging. Sampling would take place during the first 4 days of operation for

each dredge and three times during the shutdown period between dredges. Two

sampling events will also take place while clean cap material is being placed

in the CDF.

An evaluation of removal efficiency, rate of sediment resuspension at the

dredge head, and plume generation will be ongoing during this same time period

for all the dredges.

While the dredges are operating in dredging area 1, the effluent being

discharged from the CDF will also be sampled. The effluent going from the

primary cell into the secondary cell will be analyzed for 10 consecutive days

while dredges 1, 2, and 3 are working in the contaminated sediment. This effluent will also be analyzed for 10 consecutive days while cap material is

being pumped into the site. The discharge from the primary cell into the estuary will also be analyzed for a 20-day period. The split stream of effluent

entering the filtration and carbon absorption plant will be analyzed for a

10-day period. Effluent will not be discharged back into the harbor while

dredges are operating in contaminated sediment.

Samples would be taken during the first 4 days that the dredge is operating in the contaminated material. Samples would then be taken once a week for

5 weeks. This period would include the downtime prior to placing cap material

on the CAD cell, while the cap material is being placed, and several weeks

after the operation has been completed.

191
An evaluation of the plume created by this disposal operation will al,

be ongoing. This sampling will begin when the disposal operation starts ant.

will continue for at least 3 days.

Following completion of the project, one sampling event per week will be

conducted for 5 weeks.

DECISION CRITERIA

The previous section described the monitoring program that will be ongoing during all phases of the pilot study. This section describes how the data

acquired through the monitoring program will be used to determine if pilot

study operations are causing an unacceptable risk to public health or the environment that will necessitate a modification in operating procedures or a

termination of the project. This approach was developed by Mr. David Hansen

of the USEPA ERLN.

Background Conditions

Decision criteria cannot be based on the enforcement of existing state or

Federal water quality standards for PCBs because concentrations in harbor

water currently exceed standards even in the absence of dredging. In addition, decision criteria cannot be based on the accumulation of biologically

available PCB concentrations to the 2 pg/g FDA action level for seafood because PCB concentrations in indigenous organisms presently exceed this level.

Decision criteria based on detection of toxicity in site waters or sediments

are not practical, because sediments and water are toxic in the absence of

dredging.

Approach to Developing Criteria

Given these existing conditions, our approach is to develop decision criteria that are based on the premise that this remedial action will provide a

solution to what is a long-term environmental problem. This approach accepts

the risk of a short-term moderate increase in the release of contaminants or

associated toxicity, as long as the goal of long-term cleanup is achieved. It

is estimated that the release of PCBs and metals at the Coggeshall Street

Bridge will be low and within the range of background conditions. The monitoring plan is specifically designed to validate these predictions.

Preoperational monitoring data sets will provide baseline levels of the

variability of contaminant concentrations, toxicity, and bioaccumulation.

These data will allow us to determine if sample intensity or design should be

modified to improve precision of data prior to operational phases. Once the

operational phases begin, collection of identical data sets will allow discrimination of statistically significant increases in contaminants, toxicity,

or bloaccumulation. In addition, the magnitude of the increase must be

greater than a factor of 2 above preoperational phases. If both of these occur, the operation will be halted and the rate of return to predredging conditions will be monitored. Provided that the return to predredging conditions

is acceptably rapid, the operation can recommence. This procedure will be

used during each operational phase. If conditions produced by an operation

are unacceptable in both magnitude and duration, additional engineering solutions will be required before operations can begin anew.

192
Monitoring Decision Matrix

The following actions are to be included:

a. Characterize predredging conditions.

(1) Determine conditions existing at the site prior to operational

activities. Particular emphasis will be placed en water exchange at the Coggeshall Street Bridge.

(2) Select appropriate sample intensity and location for operational

phases.

(3) Develop a document that lists numerical decision criteria developed from the preoperational monitoring. In addition, the document will summarize available data from preoperational

monitoring and statistical methodologies for analyses of data

from operational phase monitoring. This document may be revised

as additional information becomes available over the course of

the pilot study.

b. Characterize conditions during construction of the CDF dike, dredging

with disposal in the CDF, dredging with disposal in the CAD cell,

downtime during dredging activities, and postoperational phases.

(1) During each of these phases and during the use of each type of

dredge, monitoring activities will characterize site conditions.

(2) Site conditions, during each of these operational phases, will

be statistically compared with predredging conditions.

c. Apply decision criteria.

(1) If no statistically significant increase is detected in data

from any monitoring activities, the project will continue. To

ensure that preoperational conditions are representative for the

site, conditions between operational activities will also be

monitored and statistically compared with preoperational and operational phases to ensure that no increase has occurred.

(2) If a statistically significant impact is detected that is

greater than a factor of 2 above the preoperational phase for

any operational phase in monitoring data from the Coggeshall

Street Bridge, that phase will be stopped and the rate of return

to preoperational conditions will be monitored.

(a) If the conditions rapidly return to those of the preoperational phase, the operation can be continued. "Rapidly"

will be defined in the decision criteria and will be based

on the preoperational monitoring data and the known flushing rates of the Acushnet River. After the operation

resumes, additional monitoring is required to confirm that

any further impact is minimal.

193
(b) If conditions fail to return to those of the preoperational

phase, an engineering solution to limit impacts must be

instituted.

(c) If conditions fail to rapidly return to those during the

preoperational phase following implementation of engineering solutions, it is possible that preoperational monitoring did not adequately characterize background conditions

during the actual time of operation. For this reason, it

may be desirable to resume the operation with planned shutdown times to demonstrate that interoperational monitoring

does not result in continued increases in detectable

impacts.

(d) Finally, if data from environmental monitoring demonstrate

that the above conditions cannot be met and that long-term,

far-field impacts are likely to result from continued operations, the project will be stopped.

Representatives from appropriate Federal and state agencies will form a

group that will be responsible for reviewing the monitoring data as they become available. After reviewing these data, the group would make decisions as

to the daily operations during the pilot study.

Example Monitoring Scenario

Day 1

The sampling plan, sample analysis, and toxicity testing described in the

section on far-field water quality would be carried out.

Day 2

The review group described above would convene to review the 24-hr data

sets and consider the following options.

a. Decision criteria violated by 24-hr data sets.

(1) Discontinue operation?

(2) Discontinue sample collection for 7-day static renewal bioassay?

(3) Continue 24-hr sampling regimen until toxicity and chemical

pulse drop to levels acceptable according to the criteria?

(4) Consider amplitude (time versus intensity) of chemical/toxicity

pulse?

(5) Consider containment strategies?

(6) Reinitiate operation?

194
b. No violation of decision criteria - Continue operations and sampling,

flood and ebb tide composite samples for 7-day static renewal bioassays, and 24-hr sample regimen.

Day 3

Collect first set of mussels and analyze for chemistry and scope for

growth.

Day 4 - Decision Point

Decision criteria violated by tissue residues and/or scope for growth:

Proceed through steps al-a6 (as for Day 2) as appropriate.

Days 5-7

Follow steps al-a6 (Day 2) if violation occurs in 24-hr turnaround data

sets. Follow step b (Day 2) if no violation occurs.

Day 8 - Decision Point

Decision criteria violated by bioassay/mussel results: Repeat steps

al-a6 (Day 2) as necessary.

Day 28

Collect remaining mussels for actual growth, scope for growth, and tissue

residue analysis.

Decision Point

195
REHABILITATION OF ESTUARIES IN TAKAMATSU HARBOR

"H. Ohira

Manager, Harbor Department

Civil Work Division

0 Kagawa Prefectural Government

C? K. Nikaido, H. Takagi

__Engineering Committee

- Japan Sediments Management Association

G _ ABSTRACT

The objectives of this project were to recover

I the natural environment of Senbagawa District around

0T Takamatsu Harbor and to prevent possible marine con-

< • tamination by dredging the organic sediment containing

polychlorinated biphenyls (PCBs) precipitated in the

estuaries of the Senbagawa River. Based on the results of a sediment survey, dredging was recommended

for sediment with 10 ppm PCB content and an ignition

loss of 20 percent or above.' This involved a quantity

of 82,000 mJ, covering an area of approximately

47,000 m2 . The related tasks (dredging, transporting,

unloading, dredged material solidification, disposal,

and covering) are described. Reference values established for the treated and discharged spillwater were:

pH, 5.8 to 8.6; suspended solids, 10 ppm or below; and

PCB content, 3 ppb or below.

BACKGROUND

Japan is composed of four major islands (Figure 1). Kagawa Prefecture is

located in the northwestern portion of Shikoku Island, facing both the Inland

Sea and the Pacific Ocean. The Takamatsu Harbor is the main harbor of

Takamatsu City. The harbor was originally constructed as a pier of the inner

city, together with the Takamatsu Castle (Figure 2). The harbor at one time

played a vital role as the connection to Honshu Island. The Seto Bridge is to

be opened in 1988 to traffic between Takamatsu City and Honshu Island.

The history of the paper manufacturing industry in Kagawa Prefecture

dates to the Nara era (A.D. 710-794). Many paper manufacturing companies were

situated along the Senbagawa River flowing into the Takamatsu Harbor and, following the introduction of paper manufacturing machines around 1904, these

companies began using PCBs. The paper manufacturing process requires a large

volume of water. The PCBs discharged with the wastewaters have precipitated

on the bottom of the Senbagawa River, eventually contaminating a total water

area of 73,000 m2 (16,000 m2 in the upper reaches of the river and 47,000 m2

in the lower reaches and estuaries).

196

92-16021
,;0 

Hokkaido

Island

Honshu sland

04

0~G

145*

00

Island

30 ______

13loe 13 40"

Figure 1. Location of Takamatsu Harbor

Inland Sea Takamatsu

Harbor Asahi-machi.

Takamatsu Fishing Port

teSenbabawa F~as

Kagawa. Takamatsu River Tsumedag w u4 i'Gl

University Castle GooaaRiver rs

Central Park

Figure 2. Dredging area

197
When it was acknowledged that PCBs would affect human health through

marine products, their use had already been prohibited in Japan. On

October 28, 1975, the Environment Agency established a tentative standard of

10 ppb or below for residual PCBs in the sediment.

To ensure the safe removal of sediment, Kagawa Prefecture conducted surveys, analyses, and studies in 1975, 1976, and 1979 and executed sediment

removal operations from 1984 to 1987 in accordance with the work execution

plan developed in 1984.

SEDIMENT SURVEY

To address the aforementioned environmental problems, sediment surveys

were conducted with 50-mesh at 42 locations between 1975 and 1979.

Sediment samples from the upper and middle reaches had an odor of hydrogen sulfide, the luster of black oil, and were muddy, with 240 to 370 percent

water content, 170 to 204 percent liquid limit, 32 to 37 percent plastic limit,

21 to 30 percent ignition loss, and 14 to 106 ppb PCB concentration. The sand,

silt, and clay content of the sediment was 4 to 14 percent, 48 to 54 percent,

and 37 to 43 percent, respectively, by particle distribution (Table 1).

Figure 3 shows the vertical distribution of PCBs from the upper reaches

to the estuaries of the Senbagawa River. The PCB concentration at the upper

reaches was from 400 to 500 ppm, which decreased toward the estuaries. The

survey results indicated that, fortunately, because of the rapid sedimentation

of PCBs, they had not been distributed to a wide area. According to the vertical distribution, the PCB concentration in the surface layer has decreased

since the prohibition of PCB usage; however, the concentration in the deep

layer shows an increasing curve. In the deeper layers, the concentration

decreases in a parabolical curve and finally approaches zero at a certain

depth, suggesting that PCB sediments started accumulating at this level.

SEDIMENT REMOVAL CRITERIA

There are no official criteria in Japan regarding the removal of polluted

sediments. However, tentative standards have been set for total mercury

(T-Hg) and PCBs. For PCBs, the reference is 10 ppm (mg/kg).

In the present dredging project, in addition to the reference PCB concentration, a 20-percent ignition loss reference was used because of the extreme

turbidity of the Senbagawa River caused by organic cohtaminants. Based on

these references, the contaminated area to be dredged was specified in the

following manner.

As shown in Figure 4, the removal depth was determined in accordance with

the vertical distribution of PCBs and the ignition loss, because of their

parabolical decrease from the surface layer to the bottom layer. As shown in

Figure 3, the layer containing a PCB concentration 210 ppm is much deeper in

the upper reaches than in the lower reaches of the river. Therefore, as iar

as the upper reaches are concerned, it was possible to confine the bottom

sediments by providing an alternative waterway. For the other reaches, however, what is called the partial-filling/partial-dredging method was employed

to remove the sediments.

198
TABLE 1. RESULTS OF SEDIMENT PROPERTIES ANALYSIS

Middle Reach

Upper Bottom Surface Lower Reach/

Parameter Reach Layer Layer Estuaries

Soil

Appearance Black Black Black Black

Odor Like ditch Like ditch Like Like ditch

mud mud hydrogen mud

sulfide

pH, H 20 8.01 7.96 7.80 8.00

pH, KC1 7.79 7.76 7.50 7.85

Water content, % 293 241 371 158

Weight per unit volume, 1.047 1.025 1.016 1.122

g/cm3

Liquid limit, % 204.3 -185.6 169.3 118.6

Plastic limit, % 35.9 37.2 32.5 23.0

Plastic index 168.4 148.4 136.8 94.7

Specific gravity 2.112 2.101 2.229 2.342

Particle distribution

Conglomerate (Ž2,000 v) 0 0 0 0

Sand (74-2,000 1) 4.0 4.0 14.0 4.0

Silt (5-74 P) 53.0 54.0 48.5 48.0

Clay (!5 P) 43.0 42.0 37.5 48.0

Eutrophic substance

Ignition loss, % 27.1 29.4 21.9 21.0

CID Mn, mg/g 109 96.9 108 64.2

COD Cr, mg/g 413 484 277 220

BOD,* mg/g <500 <500 <500 <500

T-N, mg/kg 5.510 6.320 5.220 2.860

T-P, mg/kg 540 400 692 114

Sulfide, mg/g 12.1 6.0 5.6 3.7

n-hexane extract, mg/g 15.9 10.8 5.0 3.3

Toxic substance

T-Hg, mg/kg 0.81 0.93 0.98 0.70

Cd, mg/kg 3.9 2.7

Pb, mg/kg 228 196

Cr 6+,** mg/kg <0.02 <0.02

As, mg/kg 21.3 9.5 14.2 18.3

CN, mg/kg <0.7 <0.7

Org-P, mg/kg <1.0 <1.0 <1.0 <1.0

PCB, mg/kg 10.6 14.1 30.6 9.89

PCB dissolution test, mg/kg NDt ND ND ND

* Concentration with wet sediment.

** 10 percent by weight dissolution concentration.

t Not detected (!0.0005 ppm).

199
PCB.(ppm, mg/kg)

100 2 3 4 S 6 I 10 •2 5 7 102 2 3 4 5 67 7o0 , , I , 0 I , . I 0 I , , ,I

0.5 Sr 41 vY Estuaries % 0 \,

Gln harbor t5

1.5 - IG t3 St 19

"21 Middle reaches

2.5- 0

N St 7

0 3. ~Tentative standard

sdUpper reaches S4

54.5U .i.L j LL LL ±L j

5" (Parabolical sedimentation)

6

Figure 3. PCB vertical distribution in contaminated area

Figure 4. Plan view of the dredging

project of Senbagawa Dis- -s

trict at Takamatsu Harbor

-3.

The removal depth of those reaches was as follows (with TP indication):

a. Middle and lower reaches, -3.9 m to -5.1 m.

b. Estuaries, -4.4 m to -5.4 m.

200
DESCRIPTION OF DREDGING

Dredging and Disposal Areas

Figure 5 shows the landfill area in the upper reaches of the Senbagawa

River and the dredged area in the lower reaches and estuaries. Size of the

dredged area was approximately 47,000 m2 , with a volume of 82,000 m3 . Of this

volume, 20,000 m3 was used for landfilling in the upper reaches, and the remaining 62,000 m3 for landfill at a subdivision in Tsumeda District

(Figure 6).

P Wrrk area Gererefrre-_ tea

Landfill are D•psal areal , rdigArea

30~, B 0 e staot2 ta~ 

Projected are

for road " c of

Projected area for gree erS Sbelt and parking lot • •~~• _pbar ,o iin •-It 'eo•

Culvert (new(yitn Voalp° co stored , mat . " "

c s e Tentative pits (18)

9.Om (W) x 11.5m (L) x 3.5 m (H)

Solidifying agent

mixing plant Spillwater treatment plant

'•• Scale = 112,000

Figure 5. Plan view of Senbagawa District

Equipment

For sediment dredging, the pump dredge is normally used to minimize turbidity and to simplify the operation. However, the sediment to be dredged was

not conducive to this procedure since shipbuilding yards and private houses

are crowded along the river, and the sediments contained a large quantity of

wires, timbers, vinyl bags, and other foreign materials. Accordingly, though

problematic from the viewpoint of contaminant dispersal, the grab dredge (with

2-m 3 capacity) was employed. To prevent spillage and dispersal of contaminants, a confinement-type grab was used, and protection sheets (called "silt

protectors" in Japan and "silt curtains" in the United States) were provided

around the dredge (Figure 7).

During dredging, inspection and auxiliary points were provided, where PCB

concentration and turbidity were measured once a week and four times a day,

201
Tsumeda District

(disposal area

J4-

CU

'Dredging area in

""~ w [Senbagawa

!Dsrct

so lidifying

yt7reatment pit \ NLandfill area in

-Senbagawa District

(disposal area) Scale 1/15,000

Figure 6. Location of Senbagawa and Tsumeda Districts

Clamshell

Grab Confinement-type

dredger grab bucket

Barge 

Lorry

protector Sediments Unloading Pier

Original Bottom

a. Transporting/unloading process

-''- Silt protector frame

b. Dredging process

Figure 7. Sediment dredging procedure

202
respectively. Both measurement items remained below reference values during

dredging. Foreign materials were removed at the time of barge loading to prevent problems during the treatment process.

Disposal

The dredged material was disposed in the contaminated area in the upper

reaches of the river and in a subdivision, located 3 km from the dredged area

and within a marine reclamation area (disposal area of Tsumeda District),

which was convenient for the disposal.

Upper Reaches (WaterFill), Senbagawa District

The sediment dredged by grab was loaded on a barge (with 300-m3 capacity)

and transferred to the unloading pier provided adjacent to the fill area. At

the pier, the sediment was transferred by clamshell (with 2-m 3 capacity) from

the barge to lorries that had been modified to prevent spillage. The sediment

was dumped from the temporary decks over the fill area. Seepage water from

the dredged material was fed to a spillwater treatment plant (Figure 8).

lamshellScaled lorry

Unloading Temporary

pier pier

Loading/Transporting/Unloading Process

Polyaluminum

chloride (PAC) ýSulfuric

Solidified sludge Is tTreated .ýý-f water

Soliifid sldgeSediments (to landfill area)

Covering Process

Neutralization Sedimentation Treated water tank

Coagulation Treatment

Spillwater Treatment

Figure 8. Water-fill of upper reaches of the Senbagawa River

and spillwater treatment

Since there was a plan to reclaim the area for roads, parking lots, and

greenbelt within a short period, the dredged material was treated by a special

solidifying agent that was effective even on the sludge containing a large

volume of organics with a high water content.

For the area transformed to road, this treatment was applied to all the

layers to prevent possible subsidence. Elsewhere, the area from 1.3 to 2.8 m

203
from the surface was treated. The target rigidities of the former and the

latter were 1.0 kg/cm2 and 0.4 kg/cm2 , respectively. The solidification

treatment was conducted in such a manner that the solidifying agent was fed

from the mixing plant on the shore to the dredged material by pressure pump

(Figure 9) and kneaded by the vertical mixer onboard a floating boat.

Solidifying Concentration

agent silo lant Slurry ur Generator

(Mixer)

Flowineter

.. ,

Water tank

r

C)C

00

15 20 mi

Figure 9. Mixing plant for pressurized transfer of

solidifying agent

Landfill, Tsumeda District

As the dredged material would be transported across the city from the

unloading pier to the fill area, safety measures for the transportation were

required. Also, preventive measures against secondary contamination by the

dredged material were required in the landfill area that was to be reclaimed

to vegetation. Accordingly, the dredged material was treated by a special

solidifying agent before transport to the fill area (Figure 10).

Temporary pits for the solidification treatment were provided in the area

adjacent to the dredged area. As shown in Figure 5, 18 solidification pits

were required with a unit size of 9 m(W) x 11.5 m(L) x 3.5 m(H). The schedule

for solidification treatment is illustrated in Figure 11.

Kneading of the solidifying agent and the dredged material was conducted

by a special mixer, rather than a bucket in a backhoe. Target rigidity of the

treated material was 0.4 kg/cm2 .

204
Backhoe BachoeLorry Covering soil Bulldozer

* ~ .~Or ginal

Treatment - .ground Solidifying treatment pit

Excavating/Transporting Covering Process

Process

Polyaluminum

chloride (PAC) ýSulfuric

UTreated 

water

S e to landfill area)

"Neutralization SedUienaO nTa water tank

Coagulation Treatment

Spillwater Treatment

Figure 10. Solidification and spillwater treatment for

landfill area of Tsumeda District

7 day s 4 days day

[ Filling in the ... ...... Spillwater Solidifying

dredged material separa tion treatment

7 days 1 day--------------------

CuringFilling in the

nriong Transporting ---. Y dredged material I (generation -------------------- of 

strength)

Figure 11. Operation cycle of solidfying treatment pit

The disassociated water in the pits and the rainwater were fed to a temporary spillwater treatment plant that was part of the solidification treatment system.

During this work, no complaints were raised from the public about odor,

noise, or vibrations, and no problems occurred during transportation of the

dredged material through the city.

Spillwater Treatment

Description

The wastewaters discharged during the rehabilitation works contain PCBs

whose concentration exceeds the spillwater emission standard, so that they

would cause secondary contamination if drained as they were. Therefore,

proper spillwater treatment was required.

205
Basic tests made it clear that PCBs would easily adhere to suspended

solids and would rarely transfer to water. Accordingly, if the concentration

of suspended solids was limited to below 10 mg/t, the PCB concentration would

be reduced to the reference value and the other contaminants could also be

removed simultaneously. Following the practice for such a case, a combination

system of flocculation and filtration was employed in the project as the

spillwater treatment method.

The spillwater in question was the discharge water from the upstream fill

area and from the temporary solidification pits for the landfill. The waters

were fed to the spillwater treatment systems by pump, and the treated waters

were discharged to the estuaries of the Senbagawa River. A flowchart of the

spillwater treatment system is shown as Figure 12.

pil regulator Ilnorgnic coagulant PAC

•oa alnt (gF.PAMll)

Qalek fill., l.rlng •Coagulation & iediantation

R.AInfater tank tank

A tt oc it. Autu liL at., q-1uly analysis

uikk agitation C•a

tank Dl. h t.

------- 4 lonltno ,,•

nt th

Figure 12. Spillwater treatment system

encourage 

In the the flocculation coagulation process, polyaluminium chloride (PAC) was injected to of fine suspended particles, and another high molecular coagulant (Polymer KF-PA331) was injected to accelerate the coagulation and the sedimentation.

However, since it was impossible to reduce the suspended solids to below

10 mg/L with this process alone, a dual-media filter (with sand and anthracite) was installed at the final processing stage.

206
The treated water was transferred to a monitoring tank and discharged to

the river after pH and turbidity were continuously measured. If the measured

values were unacceptable, the water was returned to the system for

retreatment.

System Operation Control

Since measurement of the PCB concentration, which is a costly process,

was one of the regulation items in the emission standard, it was necessary to

determine the concentration that could be easily measured. Accordingly, a

widely known correlation between turbidity and suspended solids was used in

this case. The results of this sediment analysis are shown in Figure 13. The

emission standard for PCBs was set at 53 ppb, which could be satisfied by

reducing the concentration of suspended solids below 10 mg/t, as discussed

before. Accordingly, the PCB concentration was easily predictable by the less

expensive monitoring of turbidity. In addition, considering the relationship

of the turbidity of spillwater, the suspended solids to be treated, and the

coagulant, a pH meter and a turbidity meter with recorders were provided for

continuous monitoring of the tank.

Treatment Results

Spillwater treatment was carried out from 1985 to 1987. Though the

designated treatment volume was 18 m3 /hr, with the returned water from the

8.0

7.0 I

6.0 y = 1.186x + 0.32

y =0.897

5.0

S4.0

3.0

2.0

1.0

00 10 20 30 40 50 60

Turbidity (degree)

Figure 13. Correlation between turbidity and

suspended solids

207
proceqs and the other waters loaded upon the system, the system was actually

operated at the rate of approximately 20 m3 /hr, on the condition that the

water discharged from the solidification process should be treated within the

day.

The qualities of the discharged spillwater (the water discharged from the

monitoring tank) were as follows:

a. PCB - 0.003 mg/i.

b. Suspended solids - 10 mg/L.

c. Turbidity - 10 degrees or below.

During the rehabilitation project, the PCB concentration in the discharged spillwater was measured 70 times. The results showed that the average

(maximum and minimum) concentrations of PCBs in the raw spillwater and the

treated spillwater were 0.011 mg/i (0.166 and not detected (ND)) and ND (ND,

ND), respectively. The results of the suspended solids measurement by the

spillwater treatment process conducted in March 1986 are shown in Figure 14.

(6,800)

2500

2000

Raw mean water value - 1,600 mg/i

1500

1000

S500

2

Water after coagulation

and sedimentation

treatment

5-

Discharge Filtered

water water Discharge water mean

1986 Mar 1 5 10 15 20 25 30

Figure 14. Time course change in water quality

(suspended solids)

208
The suspended solids removal rates in the flocculation tank and the filtration

tank were 99 and 68 percent, respectively, and that of the entire system was

as high as 100 percent.

Monitoring

As required by law, inspection points and check items such as odor, vibration, and noise were set for the quality of waters (including subterranean

water), as shown in Figure 15. Monitoring was conducted at a specific frequency before, during, and after dredging, for all the contingencies (Table 2).

Water quality

inspection

' '

\ '

Joto-cho

L •A 20m a o

e d -'-Dr g e C8 • Fukuoka-choC 20

I•Pit area

Figure 15. Inspection points for water quality,

odor, vibration, and noise

The monitoring reference values and the detailed check items relating to

water quality are listed in Table 3. The measurements in the Senbagawa River,

especially at the estuaries, indicated no problems, and the values were 0.009

or below, except those between 0.01 and 0.02 at some observation points.

Considerable odor generation was predicted by the basic tests, but this

did not become a serious problem since the work was done during winter when

the temperature was low.

CONCLUSIONS

The rehabilitation project was implemented in the manner described above.

Before initiation of the project, a variety of analyses, surveys, and tests

had been conducted over a long period. During dredging, priority was placed

on the prevention of secondary contamination and safety. Eventually, the

project was completed as planned, and a natural environment was restored in

the district. It is now expected that a better environment will be created

along the river for the benefit of the inhabitants.

209
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TABLE 3. WATER QUALITY MONITORING CRITERIA

Location Purpose Check Item Frequency Reference Value

Inspection Along the boundaries between the dredged PCB Once a day* ND (50.5 g/L)

points area and the remaining areas, the

inspection points are provided to pH Once a week 7.8-8.3

monitor the water quality of the

remaining areas COD 4 times a day 3.0 mg/I (on condition that

the background value is

s3.0. It if exceeds 3.0.

the COD concentration

should be below the background value)

DO 4 times a day ý5.0 mg/I

Oil 4 times a day ND (50.5 mg/l)

Turbidity 4 times a day Depending on the analysis

results of PCB

concentration

Auxiliary In order to satisfy the reference values Turbidity 4 times a day Depending on the analysis

points at the inspection points, auxiliary results of PCB concentrapoints are provided between the tion. The turbidity is

dredging area and the inspection adjusted as required.

points to monitor the water quality based on the relation to

the analysis results at

the inspection points and

other locations

Spillwater The points are provided to monitor the PCB Once a day* 3 g/1 or below

inspection treated discharge water from the

points spillwater treatment system to prevent Turbidity 4 times a day Depending on the analysis

secondary contamination results of PCB

concentration

Observation The points are provided to monitor the PCB Once a month ND (0.5 g/L or below)

well subterranean water to prevent contamination by PCBs from the disposal area

Standard The points are provided to monitor the COD Monitoring to be

inspection background value carried out if

points the COD concentration exceeds

3 mg/I at the

inspection

points

Turbidity 4 times a day

* If the purposes of the water quality monitoring are achieved only by measuring the turbidity on the basis of the

actual correlation between PCB and turbidity, the PCB measurement frequency may be decreased to once a week.

211
AD-P006 839 11111111 Mll li Ii Jlllll 11111l

MANAGEMENT OF DREDGED MATERIAL AT TOLEDO, OHIO

J. R. Adams

US Army Engineer District, Buffalo

1776 Niagara Street

Buffalo, New York 14207-3199

ABSTRACT

Toledo Harbor, at the mouth of the Maumee River

in northwest Ohio, is the second most active port and

largest single dredging project on the Great Lakes.

Over 770,000 m3 is dredged each year. Most of this

material has been confined since 1955. In 1983, over

half of the harbor was declared suitable for openwater disposal. Monitoring of the open-water disposal

has not shown any adverse impact on water quality.

Studies of the release or bioavailability of phosphorus (P) bound to the sediments indicate that P is

released from the sediments at a rate of from 10 to

30 percent per day. On an annual basis, dredging and

disposal account for 0.4 to 0.6 percent of the total

external loading of P to Lake Erie. High-resolution

visible data from the French satellite SPOT were used

to demonstrate the total extent of the dredging plume.

Efforts will be made in the future to use the satellite for routine monitoring. The citizens of Toledo

are strongly opposed to open-water disposal operations

and are actively pursuing a long-term management

strategy oriented toward reuse/upland disposal of all

dredged material from Toledo Harbor.

INTRODUCTION

The purpose of this paper is to provide a brief history of the management of dredged material from the navigation channel in the Maumee River and the

western basin of Lake Erie at Toledo, Ohio. The project is located in northwestern Ohio where the Maumee River (Figure 1), which drains about 16,000 km2

of highly productive cropland, discharges into the western basin of Lake Erie.

Construction and maintenance of the commercial navigation project at

Toledo have been performed by the Corps of Engineers since the initial harbor

improvements were authorized by Congress in 1866. Since that time, successive

Acts of Congress have increased the project to its current length of 22 km,

depth of 9 m below low water datum, and width of 152 m.

92-16022 212

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Waterborne commerce at Toledo, which is the second most active harbor on

the Great Lakes, consists primarily of transshipment of agricultural and

mining commodities, including wheat, soybeans, coal, and iron ore. Historical

commodity movements at Toledo are given in Table 1.

The Maumee River is first among the Great Lakes harbors in volume of

dredged material. The Maumee maintains a mean daily discharge of

140 m3 sec- 1 . This flow varies widely with frequent storm discharges over

1,000 m3 sec- 1 during rainfall runoff events. During these storms, the erosion of agricultural land contributes to the Maumee River's annual sediment

load of approximately 1,000,000 metric tons (Mt). Nearly 25 km of the river

above its mouth at Lake Erie is at lake level, and much of this sediment load

is deposited in the navigation channel from which it must be removed. The

annual dredging requirement at Toledo is approximately 770,000 m3 year- 1 .

Dredged Material

Management (Pre-1975)

Prior to 1975, the sediments dredged from the Maumee River were disposed

of strictly on the basis of economics. Dredgings were disposed simply in the

least-cost manner. This may have meant either open-water or confined disposal. Between 1866 and 1955, most of the material removed from the Maumee

channel was disposed at various locations in the open lake. Since 1955 much

of the material has been placed in confinements along the banks of the Maumee

River. These areas were less costly due to reduced transportation costs and

had the added benefit of creating valuable waterfront property for both commercial and recreational use. Material from deepening projects in the lake

portion of the channel was sidecast along either side of the channel. These

deposits created artificial shoals that have been a benefit to sports fishing,

but are a hazard to navigation during periods of low water. The first island

disposal site, Grassy Island, was built in 1963 to contain mainly sediments

removed from the river portion of the channel. This area was built strictly

because it was less costly to build and use than it was to haul the material

an additional 20 km into Lake Erie.

It was, in fact, a fortunate combination of circumstances that the cost

of dike construction was lower than the cost of the long haul into the lake,

which led to confinement of the most heavily contaminated Toledo Harbor sediments for almost 20 years before it was determined that open-water disposal

would have been damaging to aquatic life and water quality in Lake Erie.

Dredged Material

Management (Post-1975)

The era of confinement of channel dredgings because of contamination

began with the completion in 1968 of a report entitled "Dredging and Water

Quality Problems in the Great Lakes." This report recommended that contaminated dredged material be placed in confined disposal facilities (CDFs) and

led to the inclusion in the River, Harbor and Flood Control Act of 1970 of a

provision for the construction of CDFs without justification beyond the need

for pollution control. Most of the very heavily contaminated material from

the Maumee River had been confined since 1955. Starting with the completion

of a new 100-ha CDF in 1975, virtually all material dredged from Toledo Harbor

was confined.

214
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Even as late as 1975, though, there were no clear-cut criteria for determining whether sediments should be confined or otherwise restricted in disposal. In 1975 the US Environmental Protection Agency (USEPA) adopted a list

of contaminants, including volatile solids, total nitrogen, chemical oxygen

demand, total phosphorus, oil and grease, mercury, lead, and zinc, and maximum

permissible concentrations for open-water disposal. In 1977 the USEPA Region V developed a more extensive list of criteria that have become known as

the "Great Lakes Sediment Criteria." These criteria used the longer list of

contaminants shown in Table 2 and the new classes of unpolluted, moderately

polluted, and heavily polluted. These classes were based on the variation in

sediment contamination in Great Lakes harbors. Moderately polluted meant that

the harbor was about average. The elutriate test was also included in the

criteria, but no numerical standards were proposed for it. Other tests, including bioaccumulation and bioassay, have been used in evaluating sediment

quality but have never been promulgated in a regulatory manner. The decision

to approve or disapprove open-water disposal has always been made through

negotiation and subjective evaluation of the results of all testing performed.

In 1981 the Buffalo District signed a memorandum of agreement with the

USEPA Region V that set forth the terms under which the testing and evaluation

of all harbor dredged material would be performed. In addition to the evaluation procedure, the Buffalo District agreed to resample each of the District's

major harbors for a full evaluation of the continuing validity of the current

dredged material management methods every 5 years.

SEDIMENT SAMPLING

Table 2 shows the 3 levels of classification and the 18 bulk chemistry

parameters that were established by USEPA in 1976 to evaluate the suitability

of harbor sediments for open-water disposal, confinement in an in-water CDF

such as the one built in the Maumee Bay, or some other more restrictive means

of disposal. With regard to the Great Lakes Sediment Criteria, the decision

on the classification of a harbor is based on the most common (or mode) of the

20 parameters.

Historically, the bottom sediments of the Maumee River have never been

grossly polluted. Table 3 gives the results of a chemical analysis in the

Maumee River in 1983. Of the parameters that indicate heavy contamination,

the level of arsenic is actually not untypical of any agricultural soil. The

level of cyanide was probably set too low in the Criteria, as over 90 percent

of all the samples fell into the heavily polluted range. The levels of iron

and phosphorus are also typical of Maumee River Basin soils.

The testing performed in 1982 was inconclusive. Although the bulk and

elutriate chemistry indicated that many areas and parameters were unpolluted

or moderately polluted, the data were spotty, and all parties agreed that confinement of all materials should continue. The area was retested in 1983 and

showed a significant reduction in the number and extent of heavily polluted

areas. Based on these and additional bioassay tests, it was determined that

sediments lakeward of lake mile 2 could be open-lake disposed. The area

upstream of lake mile 2 is still heavily contaminated and will continue to be

confined. The open-lake disposal of 434,000 m3 of sediment dredged from the

lake portion of the channel during 1985 was the first such operation at Toledo

in 10 years.

216
TABLE 2. GREAT LAKES SEDIMENT CRITERIA

Moderately Heavily

Parameter Unpolluted Polluted Polluted

Volatile solids <5% 5-8% >8%

Chemical oxygen demand <40,000 40,000-80,000 >40,000

Total Kjeldahl N <1,000 1,000-2,000 >2,000

Oil and grease <1,000 1,000-2,000 >2,000

Lead <40 40-50 >60

Zinc <90 90-200 >200

Mercury <1.0 Not applicable >1.0

Ammonia -75 75-200 >200

Cyanide <0.10 0.10-0.25 >0.25

Phosphorus <420 420-650 >650

Iron <17,000 17,000-25,000 >25,000

Nickel <20 20-50 >50

Manganese <300 300-500 >500

Arsenic <3 3-8 >8

Cadmium * * >6

Chromium <25 25-75 >75

Barium <20 20-60 >60

Copper <25 25-50 >50

Note: All ranges in milligrams per kilogram unless otherwise noted.

* Lower limits not established.

217
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MONITORING OF OPEN-WATER DISPOSAL

The Corps and the local community were justifiably concerned over the reinitiation of open-water disposal of even marginally contaminated material.

As a stipulation of the Ohio Environmental Protection Agency's (EPA) water

quality certification of the disposal operation, the Corps was required to

conduct monitoring of the disposal for violations of State water quality

standards.

In the 3 years since the resumption of open-water disposal, the Corps has

performed water quality monitoring projects to study the impacts of the

operation.

In 1985 the program consisted of weekly monitoring. The design of this

program (Figure 2) involved measurements of water quality in the plume of

sediment immediately following its release from the dredge. The sampling boat

moved into the disposal zone to make a series of measurements near the location at which the dredge would make its next disposal. Field measurements

included dissolved oxygen at 20, 50, and 80 percent of depth, pH near the surface, and secchi depth. At this time, a sample was also taken for laboratory

analysis. After the initial set of measurements, the transect was repeated at

the same stations. After the dredge had made its disposal and moved out of

the area, the sampling boat returned to the center of the disposal area and

began another sequence of field measurements along the same transect. The

same transect was then repeated at intervals of I and 2 hr after the disposal

event. At the conclusion of the final transect and before the dredge returned

for another disposal, the boat returned to the center of the area and took

another sample for laboratory analysis. Sampling took place on 10 dates during the almost 2 months of dredging operations. During this period, no violations of Ohio water quality standards were observed to result from the disposal operations.

Phosphorus Bioavailability

Probably more important than the imnediate impacts of the disposal operation itself and possible transient water quality standard violations is the

potential for the sediment to release phosphorus. The sediments dredged from

the Maumee River are much cleaner than they were 10 years ago. Toxic substances, once present in high concentrations, have been greatly reduced. However, there has been little or no change in the pollution of the sediment by

phosphorus. Considering the emphasis that has been placed on the reduction of

phosphorus transport to Lake Erie, it is reasonable that we should be concerned over the possibility that the open-lake disposal operation might be

adding a significant additional load of phosphorus to the lake.

In order to assess this question, studies were conducted of the time rate

of availability of the phosphorus associated with the sediments for algal

growth. It is known that some portion of the phosphorus adsorbed to the sediments can be released to the water. The important question that remains is:

How much phosphorus can be released before a sediment particle is again situated on the bottom in relatively the same position as before it was picked up.

Sediment samples were taken from 12 locations in the Maumee River, Bay,

and the western basin of Lake Erie. For data analysis the stations were

219
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Figure 2. Sampling plan for water quality

monitoring in 1985

grouped by: (a) the polluted area of the river channel, (b) the area of the

river and bay from which the sediments that are open-water disposed come,

(c) undisturbed areas of the open waters of Lake Erie, (d) the areas in the

lake that are used for disposal, and (e) two stations in Maumee Bay.

The phosphorus fractions that were measured in this study are listed

below. The R-NaOH-P, or reactive NaOH extractable phosphorus, is readily

available and can be extracted from the sediment particle while it remains in

the water column at a rate of between 10 and 30 percent per day.

220
a. R-NaOH-P - reactive sodium hydroxide extractable phosphorus.

100-percent available over time.

b. T-NaOH-P - more severe extraction. Available very slowly.

c. CDB-P - citrate-dithionate-bicarbonate extractable phosphorus. Only

partially available. Requires anoxia to become available.

d. HCI-P - hydrochloric acid extractable phosphorus. Apatite mineral

phosphorus. Not available.

e. TR-P - perchloric acid digestion. Not available.

Table 4 shows the results of these measurements on the 12 samples. The

river channel samples were taken from a part of the river that is still considered polluted. The reactive NaOH-P represents about 42 percent of the particulate phosphorus. The lake channel, open lake, disposal areas, and depositional area of Maumee Bay are all very similar and contain an average of

21 percent of the readily extractable phosphorus.

It is important that the phosphorus in the lake channel sediments is not

significantly different from the undisturbed areas of the lake, as that is

part of the criteria upon which the decision to confine or permit unrestricted

disposal is made. Once removed from the channel and placed on the bottom at

the disposal area, the sediment will not alter the bottom from existing

conditions.

The studies of the time rate of release of phosphorus involved placement

of the sediment in a device called a dual culture diffusion apparatus. The

sediment is placed in a darkened vessel across a semipermeable membrane from a

culture of phosphorus-starved algae in natural light. Phosphorus that is released from the sediment can pass through the membrane where it is consumed by

the algae. The algae culture is removed periodically to determine the amount

of phosphorus that has been released from the sediment.

The results of these studies indicated that the phosphorus release rate

of these sediments was about 26 percent per day. Assuming that sediments in

these tests behave as they do in the environment, I year's disposal operation

would contribute from 20 to 30 Mt of available phosphorus to the lake. This

represents only 0.4 to 0.6 percent of the available phosphorus load to

Lake Erie from all other external sources.

Water Quality Monitoring

Since the 1985 monitoring program had failed to reveal any serious water

quality problems, the Ohio EPA directed the Corps to change the design of the

monitoring program. In 1986, monitoring was performed over a much broader

area, and on transects radiating from the center of the disposal site (Figure 3). Sampling cruises were planned without regard to the timing or placement of dredging. Many more samples were taken for laboratory analysis.

In-situ measurements were made at each of the 36 stations on the transects as

before with the addition of an additional set at 1 ft off the bottom. The

program was carefully designed so that statistical methods could be used to

detect trends and subtle changes in water quality. A reference station was

221
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Toledo water intake, one was parallel to the navigation channel, one was

223
perpendicular to it, and a fourth extended due east into the open waters of

Lake Erie. Sampling was performed on two dates before dredging began, on six

dates during operations, and on two dates after dredging ceased.

The careful design and execution of this survey enabled the conclusion

that no significant impacts resulted from the disposal operations. Two very

small changes in water quality, slightly reduced pH and dissolved oxygen, were

documented along transects that extended across the disposal zone. Figure 4

shows the variation in copper concentration over the period of sampling. Only

copper is shown because it was the only metal that frequently exceeded the

water quality criteria. However, even though the criteria are exceeded on

many occasions within the disposal zone, they are also exceeded at the reference site far removed from the operation. The copper criteria were also exceeded on one of the predredging sampling cruises. The increases in copper

concentration were probably due to wind-induced resuspension of bottom sediments throughout the western basin.

Figure 5 documents the fact that the operations had little effect on the

Toledo drinking water intake. The solid line (Figure 5a) is a plot of the

daily measurements of turbidity at the intake. The squares and diamonds along

the bottom of the graph plot the turbidity of water in the disposal area and

reference site, respectively. It can be seen that the water intake is almost

always more turbid than the disposal area. When this plot is overlain with a

graph of the Maumee River discharge (Figure 5b), it can be seen that the river

plays a great role in the variation of water quality at the intake. The remaining increases in turbidity at the intake, which is in only 4 m of water,

are due to wind-induced resuspension of bottom sediments.

Remote Sensing

An additional project was included in the 1986 monitoring program. The

French satellite SPOT obtained an excellent image of the western basin on

4 June 1986. A sampling cruise was planned to coincide with the overpass so

that water quality data would be available for calibration of the satellite

data. Figure 6a shows the unprocessed satellite image with an overlay of the

navigation channel and disposal zone. When the data are classified to enhance

levels of suspended solids in the water (Figure 6b), a plume of sediment can

be seen extending to the west from the disposal zone. Suspended solids measurements confirm that the plume had very little mass. This project showed

that very small differences in suspended solids concentrations can be measured

with satellite imagery.

DREDGED MATERIAL REUSE

As was mentioned earlier, the local community is strongly opposed to

open-water disposal of dredged material in Toledo Harbor. They are also not

inclined toward the construction of additional confinements. This leaves only

the productive reuse of dredged material as a long-term management strategy

for Toledo.

While the Corps has done much research into the possibilities of reuse

and continues to provide technical assistance to the community, current

Federal law places the financial burden for the additional costs of reuse on

224
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Figure 5. Comparison of turbidity in the disposal area and at the

Toledo water intake with streamflow in the Maumee River,

15 March-15 June 1986

226
I I

a. Unprocessed image (superimposed lines show the navigation

channel, disposal area, and sampling transects)

b. Enlarged view showing the data classified to enhance

variation in sediment concentration

Figure 6. Satellite images of western basin of Lake Erie

227
the local cooperator. It is for this reason that much of the emphasis on

reuse in the Toledo area has focused on schemes that are designed to be

profitable.

At this time the Port Authority of Toledo is actively pursuing an

arrangement with a local fertilizer supplier. Dredged material is combined

with leaf litter collected from city streets, sewage sludge, and/Ir sludgE

from drinking water treatment to produce soil that can be used for landscaping. Pilot tests with this material have been very successful, but it is

still unknown whether a market can be found for the volume of material

involved.

Other reuse alternatives that have been studied include: topsoil and

fill for a golf course to be built on very flat terrain, daily cover for sanitary landfills, agricultural land spreading, stripuine land reclamation,

shoreline protection, construction fill, and ski hills.

BIBLIOGRAPHY

Adans, J. R. 1986. "Evaluation of Open Lake Disposal Operations in

Lake Erie - 1985," US Army Engineer District, Buffalo, Buffalo, N. Y.

Adams, J. R. 1987. "Evaluation of Open Lake Disposal Operations in

Lake Erie - 1986," US Army Engineer District, Buffalo, Buffalo, N. Y.

Aqua Tech Environmental Consultants. 1984 (Feb). "Analysis of Sediment from

Toledo Harbor - Maumee River," US Army Engineer District, Buffalo, Buffalo,

N. Y.

DePinto, J. V., Young, T. C., and Terry, L. 1986 (Sep). "Effect of Open Lake

Disposal of Toledo Harbor Dredged Material on Bioavailable Phosphorus in Lake

Erie Western Basin," US Army Engineer District, Buffalo, Buffalo, N. Y.

Merry, C. J., McKim, H. L., LaPotin, N., and Adams, J. R. 1987 (Nov). "Use

cf SPOT HRV Data in a Corps Dredging Operation in Lake Erie," US Army Engineer

Cold Regions Research and Engineering Laboratory, Hanover, N. H.

US Arzy Engineer District, Buffalo. 1986 (May). "Toledo Harbor, Ohio, Confined Disposal Facility - Draft Environmental Impact Statement," Buffalo,

N. Y.

US Environmental Protection Agency. 1977 (Apr). "Guidelines for the Pollutional Classification of Great Lakes Harbor Sediments," Region V, Chicago,

Ill.

228
THE BIOFILTER SYSTEM--USE OF AQUATIC PLANTS FOR WATER PURIFICATION

T. Mishima, T. Inoue,

H. Miyoshi, H. Chino

Japan Sediments Management Association

15 Sankyo Bldg., 7-12, Tsukiji 2-chome, Chuo-Ku

Tokyo, Japan

G ABSTRACT

R--- This paper describes a mechanical system for cultivating aquatic plants (waterhyacinth, watercress) in

-• _ rivers and lakes that are severely polluted, for the

W purpose of water purification. The system also ad-

-- dresses the recovery of overgrown aquatic plants and C • reutilization as fertilizer, feed, solid fuel, or

methane gas. -

Through laboratory and field tests and use of a

•i simulation model, the water purification effectiveness I

of various cultivation, growth, and removal scenarios

can be estimated.

A plan for recovery, disposal, and reutilization

of aquatic plants is described. Experiments with test

plants in Doho Pond (3.4 ha) in Ibaraki Prefecture

demonstrated effective removal of nutritive salts,

with less energy, low cost, and no waste generation.

INTRODUCTION

Because of the increase in wastewater from homes and factories, as well

as eutrophication resulting from overfertilization of fields, the quality of

water in lakes, marshes, and ponds (hereafter called the "water area") has

worsened, limiting use as service water and for industry, agriculture, fisheries, tourism, etc. To minimize eutrophication of the water area, water quality control for sewerage along the water area and for wastewater has been executed, but the improvement is not always satisfactory. It is well known that

the removal of accumulated sludges would be most effective for water quality

improvement, but is not considered the best approach from the viewpoint of

economy. To prevent eutrophication, it is necessary to remove nitrogen and

phosphorus in water as well as the sludge. To meet these needs, the water

purification method using the nutritive salt absorption ability of aquatic

plants has been widely used. However, since almost all of the interest has

been focused on the purification ability of aquatic plants, many of the tests

have proven unsuccessful because of the difficulty in removing the plants.

229
The biofilter system, a water purification system using aquatic plants,

is a total system for water purification in conjunction with reuse of the

plants collected (Figure 1). It is based on laboratory and field tests conducted over several years.

solid fuel •• river

methane gas

O... aquatic plantss

process, ing recovery removal too%##.

transport reoa

rdrying d.;,. river• &,phosphorus'& ntoe

fedstorage 7

river

compost

Figure 1. Biofilter system

The biofilter system also promotes developed of the local area, by recognizing the harmony of nature and society.

BIOFILTER SYSTEM

Description

The biofilter system consists of four subsystems: cultivation, recovery,

processing, and reutilization (Figure 2).

The cultivation subsystem is for the purpose of promoting the absorption

of nutritive salts by the proliferation and growth of aquatic plants. The

T u ofd pM be f c s puMehm ga ;K'--" e Feua whn 'llMllllIll •

Cultivation Recovery Processing Reutilization

subsystem subsystem subsystem subsystem

Figure 2. Subsystems of biofilter system

230
recovery subsystem addresses the collection, conveyance, and storage of the

aquatic plants. The processing subsystem involves the processing of the collected plants to produce feed, solid fuel, fertilizer, and methane gas. The

reutilization subsystem produces finished products from raw materials procured

through the processing and recovery subsystems.

The biofilter system has the following advantages: resource reutilization, energy savings and low cost, ease of maintenance, and creation of intimacy with water and open-air area.

Suitable Aquatic Plants

The aquatic plants suitable for this system are those that easily absorb

nutritive salts, are easily removed from the water, and can be reutilized. Of

the various aquatic plants, 13 kinds were selected for comparison (Table 1).

Based on this comparison, waterhyacinth, which grows well in water temperatures over 150 C, and watercress, which grows quickly even in low temperatures, were selected, so that alternative cultivation of these two plants

could be made, depending on the seasons.

Waterhyacinth

This plant, of Brazilian origin, is an annual and flowers from July to

October. It grows in the temperate and subtropical zones in the Southeast

Asian countries and Japan and, because it sometimes interferes with navigation

due to overgrowth, is considered a nuisance plant. It withers in low temperatures but is rated highly in the comparison of system requirements. Accordingly, this plant was selected for cultivation during the period April/May and

October/November.

Watercress

This is a perennial plant of the rape family, is of European origin, and

was introduced to Japan around 1870. Having vigorous propagating ability, it

grows thick in a clear stream, with mustachelike roots. It is therefore most

suitable as an alternative for waterhyacinth, for cultivation from late autumn

to early spring, during the time waterhyacinth is withering.

Cultivation Subsystem

This subsystem establishes a cultivation environment that allows for

propagation and growth of the plants, collection of overgrown plants from the

waterway, and absorption of nitrogen and phosphorus in the water area

(Table 2). Consequently, the removal of aquatic plants contributes to water

purification. There are two methods in the cultivation system: inner-lake

and waterway (Figure 3).

A number of advanced technologies have been employed: the technique of

aeration and agitation of water to supply nutritive salts continuously to the

roots of aquatic plants to promote propagation, the technique of flow-type

catalytic oxidation for the removal of organic matter in water, and the technique of "greenhouses" to maintain environmental conditions (Figure 4) suitable for plant growth.

231
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232
TABLE 2. NUTRITIVE SALT ABSORPTION ABILITY OF AQUATIC PLANTS

Concentration in

Absorption Ability, g/m2lday Cultivating Water, ppm

Aquatic Plant Nitrogen Phosphorus T-N T-P

Reed 20-40 2.0-4.5 0.8-2.0 0.04-1.0

Duckweed 0.17 0.018 2.0 0.5

Waterhyacinth 0.18-0.75 0.021-0.081 0.8-2.0 0.04-1.0

Watercress 0.34 0.076 4.6-6.0 2.4-3.0

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9

Figure 3. Cultivation subsystem

(1/day) Lii.

* Warerhvacinrh

0 Watercress

alt

I. Figure 4. Water temperature and growth

factor of aquatic __ __ I plants _________ - _______ __________

'I --

, a. I

< 0 ma ,a 26

Average Water Teerature, C
Recovery Subsystem

This subsystem collects, forwards, and stores grown aquatic plants without diffusion and conveys them to the processing subsystem (Figure 5).

collecting

Figure 5. Recovery subsystem

Processing Subsystem

This system processes the aquatic plants reaped and conveyed for conversion into raw materials required for the reutilization subsystem. Drying is

the most important process of this subsystem (Figure 6).

processing subsystem reutilization

processing for feed feed

recovery solar Processing for solid fuel

subsystem solarsolid fuel

utilization processing icompost for compost

processing for methane gas fuel

fermentation-,

Figure 6. Processing subsystem

Reutilization Subsystem

This system processes the treated materials for making any valued products such as fertilizer, feed, solid fuel, or gas fuel (Figure 7).

I- feed •agriculture

livestock

subsyproceprocessingglocal producer subsysem snfertilizer consumer factories

gas econsumers

Figure 7. Reutilization subsystem

System Design

Design of the biofilter system involved the following phases.

234
Site Investigation

The water volume, water quality, bottom material, biological conditions,

topography, and water depth of the lakes, marshes, and rivers are investigated

to determine the present conditions.

Coordination with Policies

An investigation is made to determine if the function of lakes, marshes,

and rivers is satisfactory (in terms of river conservancy, water utilization,

etc.) or if it is coordinated with any other policies.

Conceptual Plan

To make the best use of the water area, a conceptual land utilization

plan is developed, including consideration of the construction of resort, educational, and cultural installations as well as the creation of intimacy with

water and open space.

Basic Plan

On the basis of this conceptual plan, the condition for the water area

purification is estimated and the basic plan is developed (Figure 8). It is

anticipated that a simulation model for water purification will be used (Figure 9), and this is the most distinct feature of the system.

Plan Execution

After obtaining funding and selecting contractors, the design plan is

implemented.

Simulation Model for Water Purification

The simulation model for water purification is a power scientific model

to simulate the water quality index for biological oxygen demand (BOD), dissolved oxygen (DO), etc., as well as variation characteristics for the production process of plant plankton, animal plankton, and aquatic plants to be

cultivated on the basis of the simulation model by DiToro et al. (1975)

(Figure 10).

By this simulation model, the wastewater load, scale, and initial amount

of cultivation of aquatic plants are established, and the amount of purified

water, water quality, and weight of aquatic plants to be collected are estimated considering the natural environmental conditions in the area.

The water area is partitioned into sections on the supposition that the

water is completely blended, and each section is the primary model based on

the ecological model.

To express the growth of plants, it is considered best to use the logistic curve. According to it, if any limiting factors, such as nutritive

235
Purpose

Assessment items Removal Of nutritive salts in water area

* Assessment of purpose

suitability I

E Z Selection of purification system

* Assessment of environmental influence

" Assessment of rmo BOD?

legislation

NO Investigation of

flow-type catalytic

"* Assessment of economy oxidation mthod

Simulation model for

water ourification

S Setting up of scale

Is purified water meeting

Assessment items NO the requirements in wate

quality?

* Assessment of

purpose suitability YES

" Basic design for recovery system * Assessment of

legistration

S~ Selection of processing system

rrocess fo eoatPrcs

Assessment of Icooost I isod solid fue fuel I ýhet.i° ~ feed°eSo~~o economy

SMethanteai Drying

_____or__ross___I0-20 fermentation water contents

SStorage Processing for S~feed TI example for

calculation igfor-' water content SDryi~ng 5-7t

example for calculation Processi~ngforsoi

Figure 8. Flowchart of basic design, biofilter system

236
Selected purificaTion s ystei ,

Identifying wastewater load

- quality of wastewater

- NH4-N, NO3-N, organic-N

| - organic P, P04-P

N O |- c h l o r o p h y l l a a m ou n t . BO B. D O)

S-ramount of wastewater

s c a e ? - - - , S e t t i n g of s c a le 1

• J i Ident ify ing init ilal cult ivat io amou.nt of

" " ~ l~aquatic plants

Identifying recovery amount of aquatic

plants Natural env iron mental

E condition

I N u m er i c a l v a l u e c a l c u l a t i on.I a m ou n t of s u n l ig h t

water temperature

. r a in f a l l a m ou n t

quality of rainwater

evaporation amount

NO etc.

SScale of purification system, purified water qisality, weight of

plants recovered!

Figure 9. Flowchart for calculation model

~Autcplant • 6on

Prol ifer tion0

I n o r g a n i c - P P l a n t p a k o O -

a 

N itrification

Gush W i as ml t o

S~Death

Organic-P Ani mal plankton i- 'ra N

•~Death

SBottom sludge

Sedi mentation 

Gush

Figure 10. Organism model

237
salts, unsuitable growing spaces, and so forth, are found, then the growth of

plants is hindered and the growth amount shows the saturated amount. In this

case, the growth curve is represented by the logistic curve.

dWt .AWt(1 - W

where

Wt = present amount after the elapse of t hours

X = growth factor (1/day)

K = upper limit of value of Wt

Results of the simulation for cultivation experiments performed four

times for 4 years using waterhyacinth are shown in Figures 11-15. The calculated figures by means of the simulation model clearly show the variation patterns for each item and indicate that the model would be practical.

0.3

a

• 0.2

SMered value Figure 11. Growth of waterhyacinth -- Calculated value

02 6 a is A2 14 112

Number of lapsed days

3.0 3.0.

0 Measured value Measured value - Calculated value z - Calculated value

z aluatdvau + 1.0-

zo

0 -T

__ __ _ _ _ _ __ _ ' • I •

0 2 4 6 1 10 12 14 I1 61 2 0 2 4 6 1 10 12 14 16 16 29

Number of lapsed days Number of lapsed days

Figure 12. Concentration of Figure 13. Concentration of

NO 3-N organic N+NH 4-N

Solar Drying Device

The solar drying device available for the system consists of the warehouse for incoming cargo, the drying unit, and the warehouse for outgoing

cargo. The drying unit functions by a two-step process (Figure 16). The

238
84

43-

9 Measured value 40 Measured value

- Calculated value 0 .I - Calculated value

6 to4 10 I 14 is is n m•1

Number of lapsed days Number of lapsed days

Figure 14. Concentration of Figure 15. Concentration of

PO4-P organic-P

(Amount of sunlight)

(inputof aquatic plants -I- Uper Rack

(Drying device)

W0 = Initial water content M2 - Output volume

W1 = Optional water content R1 Required drying days of

W2 = Objective water content WO - Wi

for drying R2 = Required drying days of

M0 = Input volume W I W 2

Figure 16. Solar drying two-step process

dry data can be calculated by means of the relative formula (index regressive

formula) on the basis of the water contents and the accumulated sunlight,

obtained from the model experiments. The flowchart (Figure 17) shows the

basic design for the solar drying device.

DEMONSTRATION TEST

Demonstration Test Plant

In 1984, a demonstration test plant (Figures 18 and 19) was constructed

in Doho Pond (3.4 ha) located in the southwestern area of Tsukuba Science

City, Ibaraki Prefecture, Japan. One section of the water area of the pond,

the northwestern part, was designated for the cultivation of aquatic plants,

while polluted (raw) water was pumped into the plant cultivating area by a

submerged pipeline. The outline of each facility is as follows.

a. Scale of the installation - Doho Pond, 3.4 ha; circulating water

volume, 300 to 800 m3 /day.

b. Main facilities.

239
Supply of aquatic plants

[initial type of device Determining objective drying

contents S(water 

[Mdel test dataLJ ICalculation of required sunlight

amount

Fg Determining area required for d d

installation of device

Installat data Uon A sme nt NOo a 

-Cost 

Y S [wAccumulated sunlight eh Calc lation of drying abilctr

amount P 1 m2 in o t at

f plant Calculation of required days for

supply [ [drying |

48.peeidvoumfnimlqhildtiler

Drying period E r

Calculation of sCalculation entry of out- Capability of

amount in warehouse ngoing amount in te processing device for incoming cargo Iwarehouse for outgoing| Icargo -

-Warehouse scale ).n

-Cost2

lr asc design I

Figure 17. Flowchart for solar drying device

(I) Cultivation facilities.

Upper Pond: 1,800 m2 in total area and 0.9 m water depth

(waterhyacinth and watercress).

Lower Pond: 160 m2 in total area and 0.1 m water depth

(watercress).

Flow-type catalytic oxidation waterway: 42.5 m in length and

48.3 m3 in volume, animal shield filter.

Agitating aeration: air dispersion pipe, 200 m in length.

(2) Recovery system - raker (absorption type), capacity of 130 m3/hr

(amount of plant absorption: 30 percent of the total absorption

volume).

240
Fiue18-ceatcohascpa

j~~j Iqw~tas, AaI~atic Aqutiatic m n area utvto 

Ft--Iyp. .. 4 . . .. . ..'. cat1lytk I

4-1rP-1 

Olsntgito

Figure 19. Tcesati plan flowchpart

Primay P-Tortvy po241
(3) Solar drying device.

Size: 6 m wide, 14 m long, 6 m high

Solar collector, 4 x 10 m; lifter; drying racks (two-step conveyor type).

(4) Composting device - fermentation tank, effective volume of 4 m3 ;

blender and plant feeder; delivery conveyor.

(5) Pelletizing device - ring pelletizer in 450-mm diam for pellet

diameter of 6.5 mm; screw conveyor; blender.

Cultivation Facilities

Plant cultivation is performed in the upper and lower ponds as shown on

Figures 20 and 21. Waterhyacinth is cultivated in the upper pond from June to

November, and watercress in the lower pond year-round. The primary facilities

are described below.

Figure 20. Upper pond (waterhyacinth) Figure 21. Lower pond (watercress)

Pond Water Circulation Device

This device pumps pond water by means of a submerged pump for conveyance

through a water pipe to the aquatic plant cultivation area located on the

other side of the pond (Figure 18). Two submerged pumps were installed: one

at the east area and the other at the west area of the pond.

Agitating Aeration Device

Duckweed, like waterhyacinth, grows by absorbing the nutritive salts of

the surface water; therefore, it may be possible that the nutritive salts of

the surface water will be lacking at times. This device promotes the vertical

blending of the water mass so that nutritive salts in the bottom can be carried to the surface.

242
Flow-Type Catalytic Oxidation Waterway

The roots of aquatic plants adhere to microbes; therefore, the plants

must have the capacity to remove organic matter. However, in the case of

flowing water, the absorption function for nitrogen and phosphorus from the

roots must be hindered. Consequently, the flow-type catalytic oxidation

waterway, with no power drive but with filter-type shields for the removal of

organic matter, was installed (Figure 22).

Figure 22. Flow-type catalytic

oxidation waterway

Recovery System

This system consists of a raker, main unit, and separator (Figure 23).

The raker collects aquatic plants to the intake port of the main unit, and the

vacuum crusher condenses the plants with water for transport. The crushed

aquatic plants are then separated with water in the separation bath

(Figure 24).

Figure 23. Recovery system flowchart

243
Figure 24. Recovery system

% .

Solar Drying System

Since the water content of recovered aquatic plants is high, a drying

system is indispensable for processing the plants into feed, solid fuel, and

compost. For drying, a solar air dryer is employed, as shown in Figure 25.

Air is heated in a solar collector and is then blown onto the aquatic plants

placed on the drying racks. The aquatic plants are put on a pallet and moved

by either a carrier or a vertical feeder for continuous drying (Figure 26).

Vent pipe

Plants to

be dried

Glass " :'

Sunlight '•

Air

Figure 25. Solar air dryer Figure 26. Solar drying device

Compost Device

This device produces compost by means of effective fermentation of

aquatic plants. The dried and crushed aquatic plants are mixed with additives

and are subjected to aerobic fermentation for about 4 weeks in a holding tank

to produce compost (fertilizer) (see Figures 27 and 28).

Pelletization Device

This device converts aquatic plants into pellets of feed or solid fuel.

The solid fuel is produced by adding a polymer binder as additive to the dried

aquatic plants; the feed is produced by adding fish powder or molasses as an

additive to the dried plants (Figure 29).

244
Loor chain block

[ondiing cocnonive.

cr r

Figure 27. Flowchart for composting device

,j I

Figure 28. Composting device Figure 29. Pelletization device

TEST RESULTS

The water quality simulation results for the test plant are show in

Figures 30 and 31.

According to the test results, the average removal of nitrogen and phosphorus was about 60 percent. The removal effect estimated by the water purification simulation was nearly the same as that demonstrated by the test

(Figure 32). For phosphorus, the concentration for inflow water was greater

than the estimated value, so that the purified water quality was worse than

the estimated value (Figure 33). The chemical oxygen demand removal rate in

the flow-type catalytic oxidation wateray (retaining time, 0.9 to 1.6 hr)

averaged 32 percent, and the suspended solids removal rate was 53 percent.

These percentages are nearly the same as those used by the gravel pebble

catalytic oxidation system perfomed by The Ministry of Construction and by

others.

The recovered waterhyacinth (approximately 40 tons) was dried and processed into compost, solid fuel, and feed. The compost produced (3 tons) was

245
IVa

-. 4-o

CLU- >

41 @

*0 cc

0 *1.44

A 4.1

4c 0

P r.

0 -H

0 . 31 '.4

U 0 cU

9: 4 u

0 V 0 0

fps aA 1.

go 14 o 0 

W:- ai,'.

ON a

* 4 c

4)a4 CAdd : g4)

:o 04246
00

4J 0

* ~41

1 S cc.. w* 410

V -4IU-

'I V -r

4- 0' 0

* c

00

3. Cn

4 00 4' C4

- -4

136 m

4100 (A6

247 a
00 ) _-,-inflo

-0- inflow water T-N . ateriT-P

.0... purified water T-N O, pueri

748•--O/ T-P O

o .O5 • .. 0.0-1 oo]0 ------- 0--"o

06.-

1985 May Jun Jul Aug Sep Oct 1985 May Jun Jul Aug' Sep Oct

Figure 32. Water quality Figure 33. Water quality

variation (T-N) variation (T-P)

supplied to the neighboring farmhouses, to their satisfaction. The feed produced (0.3 ton) was supplied to the Stockbreeding Faculty of Tsukuba University for test use. The solid fuel (0.5 ton), having a heating value of

4,500 Kcal/kg, was used as fuel made available to the laboratory at Doho Pond.

Composition of the compost (shown in Figure 34) is detailed in Table 3. Figure 35 shows the pelletized solid fuel, and Figure 36 shows the stove used

exclusively for pelletized solid fuel production.

Figure 34. Compost

TABLE 3. COMPOSITION OF COMPOST

Element Percentage

Total nitrogen 3.1

Total phosphoric acid 2.0

Total potassium 2.1

Total carbon 21.3

C/N 7.0 (value converted as dried)

248
Figure 35. Pelletized Figure 36. Stove for

solid fuel solid fuel

pellet

production

The operational cost of the biofilter system was Yen 14.7 per 1 m3 of

treated water in 1985, which is considered lower than the expenses required

for other wastewater treatment installations on similar scales. By this test,

the biofilter system was proven to be most effective in terms of water purification, production of by-products, and operational cost.

Azuchi Town Project

As part of the municipal wastewater purification activity promoted by the

Shiga Local Government, pollution prevention work was initiated by Azuchi

Town, Shiga Prefecture, in 1983 on the inflow of the Tohichi River. This

waterway receives wastewater from the city and runs into the Nishino-ko

(285 ha), an inner lake of Lake Biwa. The work utilized aquatic plants under

the direct river purification method.

Description of Work

The facilities are described below and shown in Figure 37.

a. Treatment system - by catalytic oxidation and aquatic plant

cultivation.

b. Main facilities.

(1) Waterway, 2.5 m wide, 100 m long (total 250 m2 ).

(2) Catalytic oxidation pond, 19 m2 .

(3) Aquatic plant cultivation pond, 200 m2 .

(4) Warehouse for storing recovered aquatic plants, 45 m2 .

c. Cultivation plant.

(1) Waterhyacinth (from April to October)

(2) Watercress (from November to March of the next year)

249
A 0 J for fuel,

compost, reaping drying feed, etc.

inflow• water discharge

(miscellaneous

wastewater)

pretreatment bath cultivation bath water discharge

(catalytic oxidation pond) supervising tank

Figure 37. Diagram of system performance, Azuchi Town

d. Devices available.

(1) Reaper for aquatic plants (self-driving system on rail).

(2) Hand cart.

(3) Circulating pump.

e. Scale - 50 m3 /day, average; retaining period, 2 to 2.5 days

Test Results

The tests were initiated in May 1983 by planting the aquatic plants, and

the plant recovery work was performed once a week after the plants reached

full growth in the cultivation area. The water quality investigation results

were as follows:

Raw Water Treated Water Removal Rate

Parameter ppm ppm %

BOD 9.0 3.0 67

COD 11.3 5.2 54

T-N 3.36 1.66 50.6

T-P 0.34 0.25 26

The above-mentioned work has been proved to result in the reduction of

contamination as well as environmental improvements such as decreased accumulation of sludge and waste and reduced generation of mosquitos and odors.

Furthermore, it has proved to contribute to the elevation of regional inhabitants' environmental consciousness, by their voluntary participation in the

aquatic plant removal and drying work (Figures 38 and 39).

Ancient Castle Fair, Hikone City

In the World Ancient Castle Fair held in Hikone City, Shiga Prefecture,

Japan, from March to May 1987, wastewater coming from the restaurants and all

other facilities of the fairground had been induced to the moat where waterhyacinth was cultivated for water purification, and then discharged to

Lake Biwa. In consideration of the surrounding environment, cultivation

fences were installed to enhance the aesthetics of the landscape, having

water, greenery, and stone wall in harmony (Figure 40).

250
Figure 38. Cultivation of aquatic Figure 39. Landscaping for

plants in Juhichi environmental imRiver (Azuchi Town) provement (at

Jonohama of Azuchi

Town)

Figure 40. Watercress cultivated

in fairground moat

for water purification

CONCLUSIONS

Research on the water area purification system utilizing aquatic plants

(biofilter system) commenced in 1980 and continued to 1984. During the first

3 years (1980 to 1982), the selection of aquatic plants suitable for the system, framing of the structure of each subsystem, confirmation of the practical

use of the system through various tests, planning of the calculation model for

various basic designs suitable for each application, and other fundamental investigations were accomplished. In 1983 the demonstration test was planned

for execution in Doho Pond of Tsukuba Science City in Ibaraki Prefecture,

Japan, to verify the practical use of this system. From 1983 to 1984, the

251
cultivation facilities, recovery devices, solar drying devices, compost devices, pelletization devices, and other related facilities were developed for

the system and the operational test was performed in Doho Pond.

As the result of the test, the following features of this system have

been confirmed:

a. It is possible to employ the quantitative nutritive salt absorption

ability of aquatic plants and to absorb and remove the lowconcentration nutritive salt diffused in the water area.

b. It is possible to make use of aquatic plants effectively as compost,

solid fuel, methane gas, and feed.

c. The system is saving energy because of the use of the solar drying

system..

d. The system is easy to maintain, energy effective, and operable at low

cost.

e. It is easy to create appropriate landscape on the water side using

aquatic plants.

The biofilter system is not only a water purification technology effective for the eutrophied water area but also a biotechnology by which the recovered aquatic plants can be converted to valued by-products and by which the

surrounding environment can be improved.

This system is available for application to any water areas where water

purification is a serious issue. Further, this system promotes local

participation.

REFERENCES

DiToro, D. M., et al. 1975. "Phytoplankton-Zooplankton-Nutrient Interaction

Model for Western Lake Erie, Systems Analysis and Simulation in Ecology, III."

Watanabe, Seki, et al. 1983 (Mar). "Report of Test and Research for

Eutrophied Water Area Purification System Utilizing Aquatic Plants," Engineering Advancement Association of Japan.

252
SUMMARY OF THE CE/EPA FIELD VERIFICATION PROGRAM

R. K. Peddicord

- d Battelle Ocean Sciences

397 Washington Street

Duxbury, Massachusetts 02332

0 0

__ABSTRACT

s-usebThe Field Verification Program, jointly sponsored by the US Army Corps of Engineers (CE) and the

US Environmental Protection Agency (EPA), was a 6-year

comparative study of three methods of dredged material

The $7.2-million S-disposal. effort evaluated test

U - methods for predicting and assessing environmental impacts of upland disposal, wetland creation, and

aquatic disposal as techniques for disposing of

dredged material. The objectives of the program were

to determine (a) the reproducibility of test methods

in the laboratory, (b) the ability of laboratory test

methods to predict effects in the field, and (c) the

comparative effects of the same dredged material in

upland, wetland, and aquatic environments.

The program demonstrated that methods of predicting effluent and surface water quality are useful for

evaluating whether a particular dredged material is

suitable for disposal in an upland site. Methods that

test the toxicity and bioaccumulation in wetland

plants showed fair ability to predict the suitability

of the material for use in creation of wetlands, but

the usefulness of the upland and wetland animal bioassays for this purpose cannot be fully judged until

the reproducibility of laboratory test results is confirmed. Methods with good utility for evaluating

dredged material proposed for aquatic disposal include

toxicity, bioaccumulation, intrinsic rate of population growth, and scope for growth.

In general, upland disposal produced the greatest

and most persistent impacts. Wetland creation produced considerably less impact, and aquatic disposal

resulted in relatively minor and nonpersistent impacts. This is in keeping with the physicochemical

behavior of dredged material in these different environments. A similar ranking of effects would be expected in the disposal of other contaminated estuarine

dredged material.

253 92-16024

Iumfl uniM
INTRODUCTION

Program Objectives

In January 1982, the US Army Corps of Engineers (CE) and the US Environmental Protection Agency (EPA) initiated the 6-year, $7.2-million Interagency

Field Verification of Testing and Predictive Methodologies for Dredged Material Disposal Alternatives (referred to as the Field Verification Program or

FVP). The FVP was designed to meet both agencies' needs to (a) document the

effects of placement of the same contaminated dredged material in upland, wetland, and aquatic environments, (b) verify the accuracy of techniques now in

use to predict the suitability of the material for disposal by a particular

method, and (c) provide a basis for determining the degree to which biological

response is correlated with bioaccumulation of key contaminants in the species

under study.

To accomplish the program objectives, evaluation techniques developed by

the CE, EPA, and others were applied to dredged material from a single maintenance dredging operation in Black Rock Harbor (BRH), Bridgeport, Conn. A portion of the dredged material was placed in a typical upland disposal site, a

second portion was placed in a typical aquatic site, and a third was used for

wetland creation. This provided the technical opportunity both to verify predictive evaluation procedures and directly compare the environmental consequences of the same material under three frequently used disposal conditions.

The BRH dredging project was chosen for the program because the material to be

dredged was in an industrial area and known to contain a variety of contaminants. Although the material was not considered to pose an unacceptable

potential for adverse environmental effects, it was considered sufficiently

contaminated to rigorously test the evaluation methods and to allow comparison

of effects in upland, wetland, and aquatic environments.

Studies of each of the three major disposal environments included both

laboratory documentation of the applicability and reproducibility of the technique(s) and verification of the accuracy of the laboratory tests in predicting environmental consequences in the field. Evaluations of aquatic disposal

were conducted by the EPA Environmental Research Laboratory at Narragansett,

R. I. Upland disposal and wetland creation studies were conducted by the

US Army Engineer Waterways Experiment Station (WES) at Vicksburg, Miss.

Terminology

The terms upland disposal, wetland creation, and aquatic disposal were

carefully chosen for use in the FVP to convey the essential physicochemical

characteristics that create potentials for different impacts of disposal in

the three disposal environments. The physicochemical characteristics of

dredged material in various disposal environments are the major factors controlling the potential for contaminant-related environmental impacts of

dredged material (Saucier et al. 1978, Francingues et al. 1985).

The term upland disposal refers to placement of dredged material in conditions such that the material will dry over time and take on characteristics

typical of upland soils. The drying and oxidizing of the dredged material

that occur over time can often result in a substantial increase in acidity,

increasing the environmental mobility and potential release of metals in the

254
dredged material. The biological availability of organic contaminants can

also be altered by volatilization or oxidation of the humic materials with

which they are associated. Major subjects of environmental concern with upland disposal include effluent quality, surface runoff quality, leachate quality, and lethal and sublethal effects on colonizing plants and animals

(Francingues et al. 1985).

Aquatic disposal refers to placement of dredged material within a body of

water so that it is always covered with water and remains saturated, anoxic

beneath the sediment surface layer, and near neutral in pH. Thus, the factors

contributing to the release of metals and organic contaminants remain relatively unchanged from the predredging situation. The organisms that colonize

aquatic dredged material disposal sites are typical aquatic organisms. Major

topics of environmental concern with aquatic disposal include water column

impacts during and shortly after disposal, lethal and sublethal effects on

colonizing animals, and bioaccumulation (Francingues et al. 1985).

Wetland creation with dredged material refers to placement of material

under conditions such that, after consolidation, the surface is alternately

covered and uncovered with water, but is never exposed long enough to dry and

take on typical upland soil characteristics. Physicochemically, dredged material used in wetland creation remains saturated with water, anoxic below the

surface layer, and close to neutral in pH. Wetland creation sites tend to be

colonized by aquatic organisms adapted to an intertidal existence and by typical wetland plants. Major topics of environmental concern with wetland creation include effluent quality, surface runoff quality, leachate quality, and

effects, including toxicity and bioaccumulation, on colonizing plants and

animals.

SEDIMENT COLLECTION AND MIXING

Before dredging of the BRH channel began, sediment samples were collected

along the channel and placed in a refrigerated truck at 40 C for transportation to the WES. Upon arrival at the WES, the samples were composited into

one homogeneous sample (Folsom and Lee 1982), which was then subdivided among

the researchers so that upland, wetland, and aquatic laboratory studies were

performed with the same dredged material. The composited dredged material

samples were maintained at 40 C in sealed containers until used in laboratory

studies.

SITE CONSTRUCTION

Site Selection and Design

Site Selection

The upland disposal and wetland creation sites were located at Tongue

Point, Conn., about 4.5 nautical miles from the BRH channel (Figure 1). The

Central. Long Island Sound (CLIS) disposal site (Figure 1) was selected for the

aquatic studies.

255
8 A I DOE PO TF "O

UPLAND.WETLAND

SITE •' // ~ ~NEW :.i

(A K HAVEN""

" ~CLIS

ti " -AQUATIC 0

,.'.:"." "'.DISPOSAL .. 

: " "''""" "" t....""" ASITE •':'" 

0 25 km SOUTH REFERENCE

* SITE

Figure 1. Long Island Sound area showing the location of Black Rock Harbor,

the upland and wetland study sites at Bridgeport, and the aquatic

study site at the Central Long Island Sound disposal area

Site Design

The available surface areas for the upland and wetland sites were limited; therefore, the major objective of the site design was to match a maximum

allowable filling rate to the available volume for temporary holding or ponding of water within the site to allow settling of suspended solids before the

water was discharged. Procedures found in Palermo, Montgomery, and Poindexter

(1978) and Palermo (1985) were followed for the designs of the upland and wetland sites. Approximately 2,294 m3 of in situ channel material was placed in

the upland site to achieve the desired final substrate elevation. Total surface area of the upland site was approximately 2,583 m2 . Approximately 765 m3

of dredged material was required to construct the wetland. Final total surface area of the wetland was approximately 706 m2 . Approximately 55,000 m3 of

dredged material was disposed at the CLIS aquatic disposal study site.

256
Dredging and Disposal

Because the available sites for upland, wetland, and aquatic studies were

located away from the BRH channel, transportation and off-loading of the material from barges were required. Material for the FVP aquatic studies was removed by clamshell dredge from a strip along the entire length of the study

reach, loaded on barges, and point-dumped at a disposal buoy marking the center of the selected aquatic disposal site. The remaining undredged strip of

the channel was later used for acquiring the upland/wetland material, meeting

the requirement that the same sediment be used for upland, wetland, and aquatic sites.

EVALUATION OF PREDICTIVE TECHNIQUES

The results of each evaluative technique were expressed in terms of

quantitative data, but the relative comparisons of the techniques were expressed by qualitative ratings of good, fair, and poor. A rating of good indicates that a technique showed sufficient correspondence between tests and

between the laboratory and field for most parameters to be reliably applied in

routine evaluations. If the correspondence was not so good or was not consistently good for most parameters, the technique was rated fair. Poor

ratings indicate little or no correspondence between tests or between laboratory and field data, so that the technique cannot at present be relied upon

for routine applications.

In the context of this report, the evaluation of the utility of a technique refers to the predictive reliability of the technique as demonstrated

in the FVP. This evaluation of utility does not consider the need for the

evaluation in a particular case (cost, time requirements, etc.). Therefore, a

rating of good utility for a particular technique cannot be taken as a suggestion that it be routinely used in all dredged material evaluations.

Techniques for Predicting Upland Disposal Effects

Upland Site Design

The settling and consolidation tests used to determine the filling rates,

weir lengths, and initial storage volumes required to achieve the desired

final surface elevations in the upland site proved successful. The field verification of the laboratory predictive tests was good, in that the construction based on the test results produced the desired final surface elevations

in the upland site.

Effluent Quality

The quality of the effluent during the filling of the upland and wetland

sites was predicted from the combined results of modified elutriate tests

(Palermo 1985) and column settling tests (Palermo, Montgomery, and Poindexter

1978). The reproducibility of the predictive method in the laboratory and the

field verification of the predictions of effluent quality were good (Folsom

et al. 1988). The effluent quality prediction technique was good for predisposal evaluations of potential contaminant effects on effluent quality from

upland and wetland creation sites.

257
Surface Runoff Quality

The mean concentrations of most contaminants predicted in surface runoff

by laboratory tests (Lee and Skogerboe 1984) were in fair agreement with the

values observed in surface runoff tests conducted on the upland site after it

was filled and had dried to typical upland conditions (Folsom et al. 1988).

The procedure for evaluating surface runoff water quality showed fair utility

for predisposal evaluations of proposed upland disposal of dredged material.

Although not evaluated in the FVP, the surface runoff procedure could be useful for postdisposal monitoring applications, in which the purpose would be to

quantify existing surface runoff quality and the predictive ability of the

method would be of little concern.

Upland Plant Toxicity

The reproducibility of the upland plant toxicity method (Folsom and Lee

1981) was limited because survival of plants in the upland site was almost

nonexistent (Folsom et al. 1988). Laboratory predictions and field observations of plant survival agreed well. Even so, the utility of the technique

for predisposal evaluation of toxicity to plants under upland disposal conditions was considered fair, because the reproducibility and the exposureresponse relationship were not clear. Vegetation was successfully established

only on plots amended with lime plus horse manure, and lime plus sand plus

gravel plus horse manure. Establishment of even salt-tolerant plant species

on these plots was sparse and occurred primarily in cracks where the soil

amendments were concentrated. All other plots were completely void of

vegetation.

Bioaccumulation in Upland Plants

Reproducibility of the plant bioaccumulation test (Folsom and Lee 1981)

in the laboratory was limited because survival of plants in the upland site

was almost nonexistent. The agreement between laboratory predictions of metals bioaccumulation and the bioaccumulation observed in the field was poor

(Folsom et al. 1988). At the present time the variability in these predictions limits the utility of the upland plant bioaccumulation technique for

predisposal evaluations. The method would be useful for monitoring plant tissues after disposal; the purpose of such monitoring would be to quantitate the

actual bioaccumulation taking place on the site, and the predictive ability of

the method would be of little concern.

Upland Animal Toxicity

Effects on earthworms of BRH dredged material under upland conditions

were so great that the toxicity test procedure could not be satisfactorily

evaluated. The laboratory test predicted high and rapid mortality, which was

observed in the field. However, the high salinity of the dried soil was almost certainly a major contributor and interfered with evaluation of the technique's ability to identify contaminant-related toxicity (Folsom et al. 1988).

Therefore, the utility of the upland animal toxicity test for predisposal

evaluation of proposed upland disposal of contaminated dredged material remains unknown, and research is necessary for further development of the

technique.

258
Bioaccumulation in Upland Animals

Because of the poor survival of earthworms under upland conditions, techniques for predicting bioaccumulation could not be evaluated (Folsom et al.

1988), and their utility remains unknown.

Techniques for Predicting

Effects of Wetland Creation

Wetland Site Design

The settling and consolidation tests (Palermo, Montgomery, and Poindexter

1978) used to determine the filling rates, weir lengths, and initial storage

volumes required to achieve the desired final surface elevations in the wetland site proved successful. These tests have been used extensively elsewhere, and their reproducibility was not evaluated in the FVP. The field

verification of the laboratory predictive tests was good, in that the construction based on the test results produced the desired final surface elevations in the wetland site (Simmers et al., in preparation).

Wetland Plant Toxicity

The plant toxicity test (Folsom and Lee 1981) in the wetland environment

was not evaluated for its reproducibility or ability to indicate changes in

toxicity related to changes in exposure to contaminants. The laboratory predictions of survival of Spartina were confirmed in the field, but laboratory

predictions that SporobcZus would survive were contradicted in the field. The

method should have good utility for predisposal evaluations of Spartina survival in wetlands created with dredged material, but not for evaluations of

SporoboZus survival (Simmers et al., in preparation). It appears the overall

utility of the technique depends upon the species to which it is applied; incomplete information on reproducibility also limits the utility of the method.

Further research is necessary if this technique is to be developed for routine

use.

Bioaccumulation in Wetland Plants

Reproducibility of response and the ability to detect changing bioaccumulation in response to different contaminant exposures were not evaluated. The

correspondence between laboratory predictions (Lee, Folsom, and Bates 1983)

and metals bioaccumulation in Spartina and the metals concentrations observed

in plants in the field was fair (Simmers et al., in preparation). Because of

the inconsistency and the lack of information on reproducibility, the wetland

plant bioaccumulation technique can be considered to have fair utility for

preconstruction evaluation of wetland creation with dredged material. However, for monitoring purposes, the technique seems useful, because the predictive ability of the method would not be of concern in such applications.

Wetland Animal Toxicity

The reproducibility of the method for testing the toxicity of dredged

material to sandworms Nereis virens and Neanthes succinea, mussels Modiolus

demissus, and snails Nassarius obscZetus was not evaluated. A relationship

between toxicity and exposure to contaminants was indicated by the absence of

259
survival in static laboratory tests with pure BRH dredged material, but good

survival in BRH dredged material mixed 1:3 with clean sand (Simmers et al., in

preparation). However, an exposure-response relationship was not clearly

defined. The animals survived in recirculating laboratory tests, and the same

species survived in the field, indicating fair field verification of the technique. The utility of the wetland animal toxicity test for predisposal evaluation is fair.

Bioaccumulation in Wetland Animals

The reproducibility of the test method and the ability of the method to

detect changing bioaccumulation associated with different contaminant exposures were not evaluated. Laboratory predictions of metals bioaccumulation

from the predredging BRH samples were field verified for four metals by comparing laboratory data on N. virens with field data on N. succinea, which

naturally recolonized the wetland site (Simmers et al., in preparation).

Field verification of the technique is considered poor. Although this indicates poor utility of the technique for preconstruction evaluations, the technique might be useful for monitoring where predictive ability is not of

concern. Field verification of bioaccumulation of organics was considered

fair. The utility of the wetland animal technique for preconstruction evaluations of bioaccumulation of organics is considered fair.

Techniques for Predicting

Effects of Aquatic Disposal

Aquatic Site Design

The sampling methods and calculations used to determine dredged material

volume destined for the aquatic disposal site proved reliable. The pointdumping techniques were successful, in that they resulted in a discrete,

well-defined mound at the disposal point (Gentile et al. 1988).

Toxicity

Tests of toxicity (Rogerson, Schimmel, and Hoffman 1985) were reproducible in the laboratory in that repeated tests showed good survival of all

11 test species of annelids, molluscs, arthropods, and fishes except the infaunal amphipod Ampelisca abdita, which was consistently affected. Mortality

of A. abdita was directly related to the proportion of BRH dredged material in

the sediment to which the animals were exposed. Mortality was also directly

related to the concentration of suspensions of BRH sediment. Field verification of the toxicity tests was indirect for the most part, because few of the

laboratory test species would have been expected to colonize the field site.

However, the survival of many species in the laboratory was paralleled by the

occurrence of a wide range of species at the disposal site as time progressed

(Gentile et al. 1988). Laboratory toxicity tests simulating field exposure

conditions have good utility for predisposal evaluations of dredged material

proposed for aquatic disposal.

Scope for Growth (SFG) and Bioenergetics

Scope for growth in blue mussels Mytilus edulis (Nelson et al. 1987) was

reproducible and directly related to exposure to suspensions of BRH dredged

260
material. There was good correspondence between laboratory and field SFG values in M. edulis when data collected under similar exposure conditions were

compared. Scope for growth in M. edulis has good utility for predisposal

evaluations for dredged material proposed for aquatic disposal. The technique

also has good utility for postdisposai monitoring purposes.

The bioenergetics measurements made on the polychaete Nephtys incisa

(Johns, Gutjahr-Gobell, and Schauer 1985) were also reproducible and correlated with exposure to BRH dredged material. At present, techniques for measuring bioenergetics in the field are limited to excretion and respiration, so

only these aspects of bioenergetics could be field verified. The utility of

the technique for predisposal evaluation is considered fair because only two

aspects of bioenergetics could be field verified. These two measurements

showed good correspondence between laboratory and field data. The utility of

bioenergetics techniques for predisposal evaluations or postdisposal monitoring is fair.

Adenylate Energy Charge (AEC)

Measurements of AEC in mussels M. eduZis and polychaetes N. incisa

(Zaroogian et al. 1985) in the laboratory were inconsistent and not clearly

related to exposure to BRH dredged material. There was a semblance of comparability between laboratory and field results in that field responses were also

erratic and minor. However, the utility of AEC for either predisposal evaluations or postdisposal monitoring of aquatic dredged material disposal is poor.

Sister Chromatid Exchange (SCE)

Measurements of SCE in polychaetes N. incisa (Pesch et al. 1987) in the

laboratory were not reproducible, although there was some relationship to exposure to BRH dredged material. Because of the inconsistency of response,

field verification was poor, and the utility of the procedure for predisposal

or postdisposal evaluation is poor.

Histopathology

There was not a reproducible relationship in the laboratory between exposure to BRH dredged material and histopathological response in mussels M.

edulis, polychaetes N. incisa, amphipods A. abdita, or bivalves Yoldia

ZimatuZa (Yevich et al. 1986). Field verification was fair in that minor,

sporadic responses were seen in the laboratory, and occasional scattered incidences of minor abnormalities were seen in the field. In the FVP, histopathology showed poor utility in predisposal evaluation of dredged material

proposed for aquatic disposal. In concept, histopathology could be very useful for long-term monitoring where the duration of exposure would allow for

the possible induction and manifestation of histologic changes.

Population Growth Rates

Growth, reproduction, and intrinsic rate of population growth in arthropods Mysidopsis bahia or A. abdita (Gentile et al. 1985) were reproducible and

related to exposure to BRH dredged material in the laboratory. They were not

field verified because the technique is not amenable to application in the

field. However, on the basis of the consistency of response in the

261
laboratory, the ability to detect effects at low-exposure conditions typical

of the field, and the environmental importance of the parameters measured, the

techniques are considered to have good utility for predisposal evaluations of

dredged material proposed for aquatic disposal.

Bioaccumulation

Bioaccumulation (Lake, Hoffman, and Schimmel 1985) of metals and organics

in mussels M. edulis and the polychaetes N. virens and N. incisa in the laboratory was very reproducible and was directly correlated with exposure to BRH

dredged material. When bioaccumulation data collected under the same exposure

conditions in the laboratory and field are compared, field verification of the

technique is good. The utility of bioaccumulation for both predisposal evaluations and postdisposal monitoring of dredged material in the aquatic environment is good.

COMPARISON OF EFFECTS OF DREDGED MATERIAL PLACEMENT

IN UPLAND, WETLAND, AND AQUATIC ENVIRONMENTS

Detailed quantitative comparison of effects of dredged material disposal

in upland, wetland, and aquatic environments is not possible in as comprehensive a study as the FVP because of the lack of commonality among the ecologies

of the different disposal environments. However, qualitative findings of the

FVP in terms of effects in different disposal environments can be summarized

in a few general observations (Peddicord 1988).

a. Effects tended to be more severe in the upland environment than in

the wetland or aquatic environments. This is particularly true when

the almost total mortality of some upland species is compared with

the generally low incidence of sublethal responses of animals in the

aquatic environment under actual exposure conditions.

b. At the end of the 6-year program, some plant and animal species still

were not established on the upland and wetland sites. Community

studies at the aquatic site showed rapid recolonization by a variety

of species to a benthic community typical of Central Long Island

Sound with few indications of serious long-term impacts.

c. The proportion of the species examined that showed substantial effects was much greater in the upland environment than in the wetland

and aquatic environments. The detrimental effects of upland disposal

were certainly influenced by the presence of environmental contaminants as well as by the very high salinity typical of estuarine sediments dried in upland environments.

d. Prior to the FVP, techniques for evaluating dredged material disposal

in the aquatic environment had received more developmental effort for

a longer time than techniques for evaluating upland disposal or wetland creation. Therefore, more techniques are available for aquatic

disposal evaluation than for evaluation of upland disposal or wetland

creation. The techniques available for evaluating upland and wetland

effects on plants and animals emphasize mortality and bioaccumulation. Because aquatic techniques have a longer developmental history, aquatic techniques tend to emphasize chronic, sublethal effects

262
in addition to mortality and bioaccumulation. Therefore, in the FVP,

more sublethal effects were measured in the aquatic environment than

in the upland or wetland environments.

e. Techniques for managing upland disposal sites to establish vegetative

cover proved successful. Laboratory and field data indicated that

the use of salt-tolerant plant species and extensive efforts to control soil texture, acidity, and free metals using sand, lime, and

manure would be required, and these proved effective in the field.

f. The techniques for evaluating water quality effects at upland and

wetland sites during site filling (effluent evaluations) and site operation (surface runoff evaluation) were useful predictive tools.

g. In general, BRH dredged material had a greater and more persistent

impact in the upland environment than in the wetland environment, and

impacts in the aquatic environment were the least seyere and least

persistent. Because the underlying physicochemical characteristics

that distinguish upland, wetland, and aquatic dredged material sites

are consistent wherever such sites occur, there is no reason to expect the three environments to rank differently in overall degree of

impact resulting from the dredged material. However, specific effects could differ with different dredged material.

CONCLUSIONS

The Field Verification Program has demonstrated that the environmental

effects of disposal of contaminated dredged material are greatly influenced by

the biogeochemical environment in which the material is placed. Aquatic disposal, which results in the fewest biogeochemical changes, produced the least

severe and least persistent impacts, whereas upland disposal results in the

most biogeochemical changes and produced the greatest and most persistent impacts. Wetland creation usually resembles aquatic disposal more than upland

disposal from a geochemical perspective and consequently resulted in fewer

impacts than upland disposal but more impacts than aquatic disposal.

Techniques for predicting effluent quality and plant toxicity associated

with upland disposal were verified by field studies. The effluent quality

evaluation technique was also shown to have good utility for predisposal evaluation of dredged material disposal in the upland environment. Wetland plant

and animal toxicity tests showed good predictive ability. Although plant

bioassay tests have their optimum utility for preconstruction evaluation of

wetland creation, the animal bioassay tests await confirmation of their reproducibility and ability to detect different responses to different contaminant

exposures. Both scope for growth and bioaccumulation showed good field verification of laboracorv results in the aquatic environment and have good utility for predisposal evaluation of dredged material proposed for aquatic

disposal. Laboratory toxicity results are hard to verify in the field, but

the low laboratory toxicity was consistent with the generally good survival

and recolonization seen in the field. The same is true for laboratory measurements of intrinsic rate of population increase. Both these techniques

have good utility for predisposal evaluations of proposed aquatic disposal of

263
dredged material. Several other techniques appropriate to each of the disposal environments have promise and are being refined to enhance their

utility.

REFERENCES

Folsom, B. L., Jr., and Lee, C. R. 1981. "Development of a Plant Bioassay

for Determining Toxic Metal Uptake from Dredged and/or Fill Material,"

Proceedings - International Conference, Heavy Metals in the Environment,

Amsterdam, The Netherlands, pp. 417-420.

Folsom, B. L., Jr., and Lee, C. R. 1982. "On the Adequacy of Mixing Large

Volumes of Sediment," Agronomy Abstracts, 1982 Annual Meetings, Anaheim,

Calif.

Folsom, B. L., Jr., et al. 1988. "Synthesis of the Results of the Field Verification Program Upland Disposal Alternative," Technical Report D-88-7,

US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Francingues, N. R., Palermo, M. R., Lee, C. R., and Peddicord, R. K. 1985.

"Management Strategy for Disposal of Dredged Material: Test Protocols and

Contaminant Control Measures," Miscellaneous Paper D-85-1, US Army Engineer

Waterways Experiment Station, Vicksburg, Miss.

Gentile, J. H., Scott, J. K., Lussier, S., and Redmond, M. S. 1985. "Applications of Population Responses for Evaluating the Effects of Dredged Material," Technical Report D-84-8, prepared by the US Environmental Protection

Agency, Environmental Research Laboratory, Narragansett, R. I., for the

US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Gentile, J. H., et al. 1988. "Synthesis of Research Results: Applicability

and Field Verification of Predictive Methodologies for Aquatic Dredged Material Disposal," Technical Report D-88-5, prepared by the US Environmental

Protection Agency, Environmental Research Laboratory, Narragansett, R. I., for

the US Army Engineer Waterways Experiment Station,Vicksburg, Miss.

Johns, D. M., Gutjahr-Gobell, R., and Schauer, P. 1985. "Use of the Bioenergetics to Investigate the Impact of Dredged Material on Benthic Species: A

Laboratory Study with Polychaetes and Black Rock Harbor Material," Technical

Report D-85-7, prepared by the US Environmental Protection Agency, Environmental Research Laboratory, Narragansctt, R. I., for the US Army Engineer

Waterways Experiment Station, Vicksburg, Miss.

Lake, J. L., Hoffman, G. L., and Schimmel, S. E. 1985. "The Bioaccumulation

of Contaminants from Black Rock Harbor Material by Mussels and Polychaetes,"

Technical Report D-85-2, prepared by the US Environmental Protection Agency,

Environmental Research Laboratory, Narragansett, R. I., for the US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Lee, C. R., Felsom, B. L., Jr., and Bates, D. J. 1983. "Prediction of Plant

Uptake of Toxic Metals Using a Modified DTPA Extraction," The Science of the

Total Environment, Vol 28, pp 191-202.

264
Lee, C. R., and Skogerboe, J. G. 1984. "Restoration of Pyritic Soils and the

Quantification of Erosion Control," Miscellaneous Paper EL-84-2, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Nelson, W. G., et al. 1987. "Effects of Black Rock Harbor Dredged Material

on the Scope for Growth of the Blue Mussel, Myjtilus edulis, After Laboratory

and Field Exposures," Technical Report D-87-7, prepared by the US Environmental Protection Agency, Narragansett, R. I., for the US Army Engineer Waterways

Experiment Station, Vicksburg, Miss.

Palermo, M. R. 1985. "Interim Guidance for Predicting the Quality of Effluent from Dredged Material Disposal Areas," Environmental Effects of Dredging

Technical Notes EEDP-04-1 through 04-4 (also published as Miscellaneous

Paper D-86-1), US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Palermo, M. R., Montgomery, R. L., and Poindexter, M. 1978. "Guidelines for

Designing, Operating, and Managing Dredged Material Containment Areas," Technical Report DS-78-10, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Peddicord, R. K. 1988. "Summary of the CE/EPA Field Verification Program,"

Technical Report D-88-6, prepared by Battelle Ocean Sciences, Duxbury, Mass.,

for the US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Pesch, G. G., et al. 1987. "Sister Chromatid Exchange in Marine Polychaetes

Exposed to Black Rock Harbor Sediment," Technical Report D-87-5, prepared by

the US Environmental Protection Agency, Narragansett, R. I., for the US Army

Engineer Waterways Experiment Station, Vicksburg, Miss.

Rogerson, 0. F., Schimmel, S. C., and Hoffman, G. 1985. "Chemical and Biological Characterization of Black Rock Harbor Dredged Material," Technical

Report D-85-9, prepared by the US Environmental Protection Agency, Narragansett, R. I., for the US Army Engineer Waterways Experiment Station, Vicksburg,

Miss.

Saucier, R. T., Calhoun, C. C., Engler, R. M., Patin, T. R., and Smith, H. K.

1978. "Dredged Material Research Program: Executive Overview and Detailed

Summary," Technical Report DS-78-22, US Army Engineer Waterways Experiment

Station, Vicksburg, Miss.

Simmers, John W., et al. "Synthesis of Results of the Field Verification Program Wetland Disposal Alternative," Technical Report (in preparation), US Army

Engineer Waterways Experiment Station, Vicksburg, Miss.

Yevich, P. P., et al. 1986. "Histopathological Effects of Black Rock Harbor

Dredged Material on Marine Organisms; A Laboratory Investigation," Technical

Report D-86-1, prepared by the US Environmental Protection Agency, Environmental Research Laboratory, Narragansett, R. I., for the US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

265
Zaroogian, G. E., et al. 1985. "Laboratory Evaluation of Adenylate Energy

Charge as a Test for Stress in Mytilu6 edulis and Nephtys incisa Treated with

Dredged Material," Technical Report D-85-3, prepared by the US Environmental

Protection Agency, Narragansett, R. I., for the US Army Engineer Waterways

Experiment Station, Vicksburg, Miss.

266
RELATIONSHIP BETWEEN THE ENVIRONMENT AND KASAI MARINE PARK

qzt - . •. T. Hiwatashi

"Bureau of Construction of the

( l •,.•o" Tokyo Metropolitan Government -CD

T. Tsukagoshi, H. Nakai, Y. Doyama, S. Wano 0 Bureau of Ports and Harbors of the

Tokyo Metropolitan Government

11 ._K. Irie

Japan Sediments Management Association -

INTRODUCTION

The Port of Tokyo, once called "Edo-Minato," is located in the inner part

of the Bay of Tokyo and has a history of 500 years. The Port has been developed both to handle navigation traffic and to serve as a fishing area for the

residents of Tokyo and adjacent cities. Since the Meiji age, the Port has

played an important role as the main entrance to the city for commercial

traffic.

Environmental pollution of the bay, especially of the water quality, has

been accelerated by industrial development and overcrowding (since 1955).

Fishing activities were discontinued in 1962, marking the direct influence of

pollution on the life of people around the bay.

These circumstances prompted the design of the Tokyo Metropolitan Marine

Park Project in December 1970, with the main objective of restoring the former

conditions of the bay. Construction of the project began in 1972. The aim of

the Kasai Marine Park is to function not only as a bathing resort and to stabilize the beach physically, but also to recover and maintain the natural environment around the park and to provide a recreation area for nearby residents by using refined techniques to construct an artificial beach.

The Kasai Marine Park has been established between the mouth of the

Arakawa and Edogawa Rivers near the boundary of Chiba Prefecture, located on

the eastern side of the Bay of Tokyo (Figure 1). A natural tidal flat called

Sanmaizu lies in the offshore area in front of the park, with adequate water

quality and sediment. Figure 2 illustrates the process for construction of

the park.

The tidal flats in the Kasai region were extended to the mouth of the

Sakongawa River before construction of the park began in 1972. About a third

of the tidal flats have disappeared due to reclamation of the background area

for the Kasai Marine Park, which occurred from 1973 to 1976. Most of these

tidal flats, however, were in the area where pollution of the benthic environment had been the worst.

Coincident with the reclamation, preliminary experiments on constructing

permeable banks have been conducted since 1974 with H-shaped steel and soft

267
•OO0GAWA

METROPOLITAN I •;•

StUMLUAGAWA2

S •TOKYO PORT CHIBA PORT

YO'KOH.M PORT O

CHIBA PREFECTURE

g D SURVEYED AREA

Figure 1. Project area in the Bay of Tokyo

sandy rocks. In these experiments, the artificial beach was raised from the

offshore side of the banks, using surrounding sand and an additional

160,000 m3 transported from Kashima, Ibaraki Prefecture, for a total of

200,000 m3 over the 1,400-m length and 120-m width. The experimental beach

was completed in 1975.

Since 1981, the artificial beach has been raised based on the results of

the preliminary experiments described above. Two banks that were brought to

completion in 1985, which are 1,500 m long on both the eastern and western

sides, form the base of the artificial beach.

Except for a portion of the western side, creation of the artificial

beach has been completed, using pumps to move sand from behind the banks.

This report presents the results of the experimental construction of the

artificial beach to support benthic organisms and the results of environmental

surveys in the park area, including a natural tidal flat (Sanmaizu), to allow

more effective use of the park and adjacent area.

268
KaaiMain Par

V/ 211/

1it' 11 - l•son" 

Figure 2. Construction process for

Kasai Marine Park

EXPERIMENTAL CONSTRUCTION OF THE ARTIFICIAL BEACH

The objectives of the project to establish Kasai Marine Park were to

create the artificial beach, preserve the surrounding natural environment, and

promote recreational use. Construction of the park has been carried out

simultaneously with environmental surveys because a park of this scale has not

been attempted in Japan before.

Construction of artificial beach shown in Figures 3 and 4 was accomplished to examine the preservation or recovery of the natural environment,

since we were unable to simulate these processes with an experimental model.

269
-C

I..

Figure 3. Artificial beach in the Kasai area

Subrerqed breakwater -stabLihed provisionaL banki

c- -- -10"

Figure 4. Section profile of the artificial beach

The raised area of the artificial beach has 50 to 80 percent mud composition with 0.0625-mm mean grain size diameter (Akiyama et al. 1974). The beach

was created with an inclination of 1/100, covered with fine sand (mean diameter 0.25 mm). As a result, the bank provided attachment for barnacles and

mussels, as discussed in Hiyama (1976), Akiyama (1974, 1975, 1976, 1977), and

Hiwatashi (1977). Benthic organisms appeared in the beach 3 months after

beach creation.

Figure 5 shows the changes in benthic organisms 2 years after the transport of sand to the beach. Gammaridae (Amphipoda, Crustacea) and Polychaetae

were distributed before the beach creation (Akiyama 1976), in contrast with

the latet settlement of sand dwellers such as Scopimera gZobosa (Brachyura,

Decapoda, Crustacea), SoZen strictus, and Mactra chinensis (Heterodontina,

Lamellibranchia, Pelecypoda, Mollusca). Pseudopolydora sp., Neanthes spp.,

(Spiomorpha, Sedentaria, Polychaetae), and Cyathura muromiensis (Anthuroidea

isopodae, Crustacea) showed significant increases not correlated with beach

establishment. As for the polychaetae Pseudopolydora sp., the population

almost disappeared 15 months after beach creation, in spite of the normal

early-spring peak in abundance, which is considered to be based on the seasonal or annual fluctuation.

270
300 Cyathura mnuromlensifls

[ M.. actm teeeriiormis 50C- JJ"1- flDmaia J appl~

1000 V -..... udi---FrhiniH i",--a-• ,-, ........ 1-"-.:

/ II ucuu senho.. si Peudopolydra til.

>11500[ .L _ _ _ _ _ _ _ _ _ _ _ _

rondidlelllaponka 50 C as wtlitpp.

-,. 4 0 - ,sPP. r- E Glyc0 2 5 8 9 11 15 24 28 0 2 5 8 9 11 15 24 28

Months after beach creation

Figure 5. Changes in benthos distribution after creation

of artificial beach at the Kasai area

As a result of the beach creation described above, it was noted that the

benthic fauna was dominated by sand dwellers that had recently settled in the

surveyed area. However, no effort was made to quantify the changes in the

population structure of the organisms.

SURVEYS CONDUCTED

Benthic Biota Survey

The purpose of the survey was to investigate the current distribution and

characteristics of the benthic biota around the park.

Methods

Triplicate bottom samples were collected at 12 stations (shown in Figure 6) using the Ekman-Berge sampler with a mouth of 0.12 m2 . Samples retained after sieving with 1-mm mesh were identified and counted. Samples were

taken four times: in August 1985 and in March, April, and August 1986.

Results

The number of identified species ranged between 32 and 65, with a maximum

density of approximately 5,000/m2 in March 1986. The biomass ranged between

30 and 40 g, dominated in both numbers and species by polychaetes during the

sampling period (Figure 7). Major species identified were: Paraprionospio

pinnata, Prionospio japonicus, Polydora sp., PseudopoZydora sp., Rhynchospio sp., Armandia sp., Musculus senhousia, Ruditapes philippinarum, and

Grandidierella japonicus. Three species, Pseudopolydors sp., Rhynchospio sp.,

271
C il

S -- ASA: MARINE PARK .. I .. ...

-CAuq Mar Apr Alia

1985 1986 966 1986 z

I .

1985 19a6 1986 198,6

T; ;,

10~ -C

Aug Mar Az Aug

Figure 6. Sampling stations for Figure 7. Seasonal fluctuations

benthic oiganisms of benthic organisms

and Armancdia sp., were the major inhabitants of the tidal flats. In all

cases, their abundance peaked in the spring, as shown in Figure 8, which

illustrates the distribution of A1mandia sp.

In contrast, Paraprinospio pinnata and Musculus senhousia, known as index

species of organic pollution, were found at the station situated in deep

sites. Ruditapes phl~ppinariwl7 was found throughout, from the shallow to the

deep sites.

The sampling area was characterized by the domination of both PseudcopoZydora sp. and Rhynchospic sp., especially at tidal flats in the spring; a lower

abundance of these species in the summer, along with the increase of R.

philippinarwn; the appearance of P. pinnata throughout the year, and the

abundance of G. japonicus in the summer at deeper sites.

Some differences were considered to be related to location (eastern and

western side of the beach) and also to the effect of the river discharge,

based on surveys made on the contours of the tidal flats, supplemented by mud

sampler stations. Benthic organisms found in the park area were dominated

272
KASAI MARINE, JAL *X"J

PARK-APR

I4

'C

'C /

i*

[ 4. .

II

C.C

Aug,1985 uar,1966

1 U KASA A.0 :1050 3: 50

- 4 1c 0 200 5:Oe0 -

1/ 0

Apr,.1986 Aug, 1986

l: Under l0 2:10-SO 3:50-100

4:100 -200 5: Over 200 Inds/O.12 m2

Figure 8. Distribution of Arnandia sp. on the

tidal flats of the Kasai area

by the polychaetes Neanthes japonica, Neanthes succinea, and Diopatra sugokai

and the bibalve Mactra veneriformis, which were less abundant on the western

beach than on the eastern beach.

It might be that the western beach has a smaller area of tidal flat and

steeper slopes than the eastern beach and that the southward waves occurred

mainly in summer, which directly affected the stability, consequently disturbing the habitat of benthic organisms in the area.

It is worthy of note that some effects on benthic organisms in the eastern beach would be expected from waters of Edogawa River, as the survey shows

the increase of individuals of Corbicula japonica, P. japonicus, and

Macrophthatmus japonicus and the decrease of R. philippinarum.

273
To summarize, the tidal flat, including the artificial beach in the park

area, might maintain its function as a beach, in spite of the pollution around

the park.

As for the artificial beach, it is important for the preservation of the

tidal flat to first solve the Edogawa River drainage problems on the eastern

beach and the stability problem of the western beach.

Survey of Seawater

Temperature and Salinity

Since the park is located between the mouths of the Arakawa and Edogawa

Rivers, the fluctuation of environmental conditions, especially seawater

temperature and salinity, might affect the growth and distribution of the organisms inhabiting the tidal flats around the park.

It is very difficult, however, to determine the fluctuation of the abiotic environmental factors in tidal flats because of their complex topographical characteristics and the rapid temporal changes.

The automatic salino-thermometer with memory function was used in the

survey, rather than ordinary water samplers or the electrical salinometer, to

determine the fluctuation of temperature and salinity at the representative

sampling station.

Methods

Salino-thermometers (Figure 9) were located in the bottom sediment and

exposed to seawater (Figure 10) to determine the water quality nearest the

benthic organisms at the sampling stations shown in Figure 11. At two of the

three stations, the apparatus was placed at 5 and 10 cm beneath the bottom

surface to expose their sensors.

4 =,

"P .M -OW - .

Arm IOi

41C W

T4000 CT- 2000

Figure 9. Salino-thermometers with memory function

Five surveys were conducted between May and September 1986 (each with

10-mI intervals).

274
Surface

.. . ....... -

Figure 10. Placement of the

salino-thermometer

KASAI MARINE PARK

bec

X Ea--er- boa" h

Figure 11. Sampling stations for survey of

seawater temperature and salinity, Kasai area

Results

Figu..res 12 and 13 show the fluctuations of seawater temperature and salinity at each station. Both temperature and salinity fluctuated less farther

from the mouth of the rivers. The temperature 10 cm from the bottom did not

change as sharply as that at the bottom (Figure 14).

275
St Date may,19S6 June July AuguSt September

-- S "I

I....I..

I ........ ........ .......... no......... i.i................

LA-- 14 [1:- ,- ,,.__ ___,_____ _ __ _ ,.,__ _ __ _ __ _ _

Figure 12. Fluctuations of seawater temperature

at sampling stations

tSeptember

iay,1986 1 July AugustS

A 5- 1 oo.

*i . 0 00 j to a 000 ,o 

Figure 13. Fluctuations of seali ate samper satu

Fiur 3. Fucutinso slniyat sampling stations

Mixing rates of river and seawater based on the chlorine concentration of

Edogawa River water, measured at a point 3 km from its mouth (Table 1), showed

a 2 to 1 ratio of riverwater to seawater near the mouth of the river, though

a 1 to 0.3 ratio of those far from the mouth. The dilution rates at the two

stations were 0.7 except in July. These data suggest that river turbulence

was not demonstrated during the survey periods.

276
.y,1986 Y 

t Temperature t S00 0 . . . . . . . . . . . . . . . - - 0.0

JS 0 . . 35. 0

30 0 _30. 0

20 0 020. 

St.:A-S Bottom

St-: A-5 Bottom-5.0cm

St.:A-5 Bottom-10.Ocm

Figure 14. Temporal changes of seawater temperature at the

stations at depths of 0, 5, and 10 cm

Figure 15 shows the distribution of the clam R. philippinarwn, as a

representative benthic organism in the area. Large quantities of this clam

have been found fairly near the beach in spring and offshore 4.n summer.

Table 2 shows the frequency of the seawater mass with specific gravity

lower than 1.015 at each station. It was suggested that the distribution of

clams in the area is controlled by the density of seawater, not by the properties of benthic substrate composition, as generally considered. This was

based on the decrease of seawater density that was found at the stations near

the mouth of the river in summer and the fact that the particle distribution

of bottom samples did not agree with the distribution of clams collected

coincidentally.

Park Usage Survey

The western beach will be used for shell gathering and for a fishing

area, while the eastern beach will be used for natural environment preservation, after the opening. The surveys were made to obtain baseline data for

future use.

Methods

Monthly surveys were made of the number of boats, users, and fishing

methods used in the park area at daytime low water on each holiday from April

1986 to March 1987. Questionna4 " were used to record data on the age, sex,

and visiting time of users from eipril to December 1986.

277
TABLE 1. CHARACTERISTICS OF BOTTOM WATER SAMPLES AT

STATIONS A-5, A-14, AND A-21

May June July

Mixing Dilution Mixing Dilution Mixing Dilution

Station Salinity Rate Rate Salinity Rate Rate Salinity Rate Rate

A-5 16.7 0.51 14.2 0.42 17.6 0.54

0.68 0.67 0.93

A-14 23.0 0.75 19.0 0.62 18.7 0.58

A-21 29.4 1.00 -- 28.7 1.00 -- 29.8 1.00 -

August September

Mixing Dilution Mixing Dilution

Station Salinity Rate Rate Salinity Rate Rate

A-5 10.8 0.36 12.2 0.40

0.72 0.70

A-14 13.6 0.50 15.8 0.57

A-21 23.8 1.00 -- 25.2 1.00 --

278
KASAX MARINE I ( LKASAI MARINE u- PARK -2 PARK -

"- •

7: Under 10

L4 0c

2 .. I j

S@ hilds/O.j in2,1

I 1u/1985 MaKASA6 MARINE

S/•

•5: Over 20

AptJ,1985 "" , u ,1986 I..

Figure 15. Horizontal distribution of the clam

R. philippinarwn on the tidal flats

TABLE 2. MONTHLY FREQUENCY OF SEAWATER SPECIFIC GRAVITY

LOWER THAN 1.015 AT STATIONS A-5, A-14, AND

A-21 FROM MAY TO SEPTEMBER 1986

Station, % Date A-_ A-14 A-2_I AveraMe,

May 4.5 33.3 0.0 13.5

June 72.2 71.8 0.0 44.3

July 100.0 56.9 0.0 48.8

August 100.0 100.0 56.7 84.1

September 100.0 100.0 37.3 77.6

279

•ili munnlia i i e ~~~PR m i a PARK 
Results

Three rainy days occurred during the 12 monthly.surveys. However, these

probably had little effect on fishing use since the precipitation was <0.5 mm.

Winds were calm on all survey days, except in April 1986, when the wind was

approximately 10 m/sec.

Figure 16 shows the boats counted in the park area along with the shell

gatherers on the Sanmaizu tidal flats. After that time, boats in general

'a as.rn, beach

it Western 5each

SAll area

S as 0 Coinerclai boata

SRecreation boats 2 isherles boats Total

i I I i i t i • Is 3 3

Figure 16. Monthly numbers of commercial, recreational, and fisheries boats

appeared fewer, with commercial boats (such as ferry boats) being counted more

at specified periods than recreational boats. Around the artificial beach,

38 boats appeared near the eastern beach while only a few were seen near the

western beach, except in April.

Though not in the park area, many boats fishing for the common brackish

goby, Acanthogobius flavimanus, appeared at the mouth of the Edogawa River

from September to November; also, several boats were resting on the artificial

beach.

280
Table 3 shows that users appeared more on the Sanmaizu from April to August, but more on the eastern beach after August. (See Table 4 for monthly

frequency of visitors during the period April-December 1986.)

The questionnaire data indicated that users aged 30 to 40 appeared more

and also that many families visited the park from April to June, so that lower

ages increased. Users from Tokyo were dominant, followed by users from

Saitama or Chiba Prefecture.

As for the fishing methods, we observed the use of gill nets, tow nets,

dredges for clam gathering, brush traps, and pot traps, which were used near

the artificial beach.

Counts of users in the park area revealed that, at present, most users

visited the eastern beach or the Sanmaizu, which is planned for development

for conservation, while only a few visited the western beach, which is planned

for recreational development. Further investigations are considered necessary

for management and the maintenance of the park area before completion of the

western beach.

CONSIDERATIONS FOR THE FUTURE

Investigation of the fauna around the Kasai Marine Park, with regard to

fish distribution (Nakamura 1960) and shells collected at Sanmaizu tidal flat

(Suzuki 1971), has been included as part of the working report on the fishery

area of the Bay of Tokyo. The results have shown that sites around the park

were leading fishing areas in Japan until 1960, with a plentiful commercial

fishery including molluscs such as R. philippinarum, Meretrix meretrix,

Anadara subcrenata, Anadara broughtonii, Lateolabrax japonicas, and Sillage

sihcmaa.

The pollution of the inner parts of the Bay of Tokyo, however, has been

accelerated, mainly by the rapid industrial development and reclamation of

lands around the Bay since the 1960s. Such conditions have continued to the

present, with a peak in 1970, causing increased anaerobic conditions in the

fishing area accompanied by red tides, hypoxia, and abiotic area, which prevent the growth of organisms in the bay.

Therefore, this area has gradually decreased as an effective fishery and

has experienced a decline in biological productivity. This decline might be

supported by the report that the commercial shell fishery in the bay has decreased because of the mass mortality of the clams R. philippinarwm and

M. meretrix in summer and autumn (Tamura 1970).

Recently, recognition has been given to the important roles of tidal

flats, not only as resting areas for migrating birds and as the nursery

grounds of fish fry, but also for their notable capacity for selfpurification. Also, because most of the tidal flats are situated near the

cities, the areas are likely to be affected by human activities.

Figures 17-19 show the sampling stations and the profiles of total sulfur

and chemical oxygen demand (COD) of the bottom samples in the inner parts of

the bay. The bottom conditions around the park have remained relatively good

281
A 1 0.0- - 000 0 0 en0 cn C 0' 0 00000 .4

W 0

9O. A t000 0 000 0 000 0 000 0 0000 0

SU.,

ZZ

m0 -0 A 1 0-0 - 000- 000 0 0- - "-'00 M

cc v

00

-0Z A I c 0 - 000 0 0 0 It OO0 U24n1 0 0.(' en c- -C - N4

mb] 

z 0

- 00 A 1 -4 "00'0 O N 00 .. 0 4 V4'0 

c;' 34 CU.4 -4 % N4 

zA I 00-N 4'- N-0 (.4 0 0 - 00' C4(f -7 m

w. C.) .

Z.

0 m0

0 r~

,c' -5 A 1 (..N N 0 00 '1 ' ' n 0 .010

N C4. m In -en 0 N1 .0' C-4

4/2 1.4D

V) .0 -). A I n 0' 00-c - Doe).Oo a,- N'D~ 0(Y 0-0.0 -

A C0 0-0. en('0a, 1 q0 40 2 I 2ODN

~ 0' A n OD'0 0' 00. (700 C7 2' -'.74 0 0002 - 0'~~~~ý ~4 ~ '0 ('4 W '2 N 00 .0

4.. r -14-

w~ 40 u 4 w 4 4 4

VZ w 0~. 0 w 0 - N '.C. w 4- 0 w wv0 0 0' O O N

C u - . N ) u0 A t.0 U.U. lf4i .0 No Or. - 3.' c.- 0 0 -1 N i (. 100 U.'- Z

428
TABLE 4. MONTHLY FREQUENCY OF VISITORS TO

KASAI PARK, APRIL-DECEMBER 1986

Total

First-Time 1-2 Visits/ 3-4 Visits/ 5+ Visits/ No.

Date Visitor Year Year Year Total Users

27 Apr

Number 8 5 1 5 19 380

Percentage 42.1 26.3 5.3 26.3 100

11 May

Number 14 3 4 5 26 1,312

Percentage 53.8 11.5 15.4 19.2 100

8 Jun

Number 13 3 4 5 25 1,781

Percentage 52.0 12.0 16.0 20.0 100

20 Jul

Number 14 3 4 1 22 647

Percentage 63.6 13.6 18.2 4.5 100

24 Aug

Number 3 12 3 8 26 374

Percentage 11.5 46.2 11.5 30.8 100

7 Sep

Number 1 1 4 3 9 393

Percentage 11.1 11.1 44.4 33.3 100

5 Oct

Number 0 0 0 1 1 202

Percentage 0.0 0.0 0.0 100.0 100

3 Nov

Number 1 0 0 3 4 47

Percentage 25.0 0.0 0.0 75.0 100

7 Dec

Number 0 0 0 0 0 1

Percentage ..........

283
TOXYO METROPOLITAN

SUIOAGAWA RIVER ARANIAWA RIVER

ZOOAAWAWA VIVSR

LL "orr 0 THE COAST

Or KASAI

T JAGAWA

RIVER)

C I I C C Cm

Figure 17. Sampling stations for sulfur and COD

compared with other areas of the Bay. Although the commercial fishing activities have been severely affected, the area around the park has not declined to

the extent that inhabiting organisms have become extinct.

The artificial beach of Kasai Marine Park is scheduled for completion in

1988. This area will provide recreational facilities for the metropolitan

residents (approximately 120 million people) and will preserve the sole tidal

flat remaining in the region. To satisfy these two purposes, balanced

management of the park is of extreme importance.

The expansion of the Sanmaizu tidal flat is predicted to recede toward

the coast over time (see Figure 20). A tremendous decrease has been observed

in the abundance of short-necked clams, Ruditapes philippinarum, and the common brackish goby, Acanthogobius flavimanus, compared with numbers from 1970.

Therefore, it will be a significant future objective to establish suitable

survey methods for dealing with these situations and to properly manage the

park.

284
I-s

S OFF THE COAST OF KASAI

"-----" OF oA ST OFASAI

Q U.

'4ill 0--. --. 0 am.

I ',•. iIl"

OFF THE COAST OF KASAI

~~Figure 19 . Annual fluctuation COtoseieta of smpe

i,28

• a I, . Ii. . . .

'\ i \I

...-.- a.3

OOFF COAST THE OF KASA!

Figu Fiure19 . Annual fluctuation ODnseintotal of le

sufrcntnsi5sdmn

• .. • =m~~i mm mmm m m mm mmmo
/ A Sl MAftlYi PARK

...

Figure 20. Annual fluctuation of the

Arakawa Point Zero Meter

contour

REFERENCES

Akiyama 1974, 1975, 1976, 1977

Akiyama et al. 1974

Hiwatashi 1977

Hiyama 1976

Nakamura 1960

Suzuki 1971

Tamura 1970

286
VOLUME CHANGE PREDICTION OF PUMP-DREDGED CLAYEY SOILS

H. Shinsha, Y. Makimoto, Y. Watari

Japan Dredging and Reclamation Engineering Association

2-8, Toranomon, 1-chome, Minato-ku, Tokyo, Japan

- ABSTRACT

In the disposal of dredged material in reclama-

- tion areas, the relationship between the volume of the NO

dredged soil and the volume of the reclamation area

must be rectified for proper disposal.

This report describes the results of a study on =__

the state of sedimentation of soil particles and the

state of consolidation of deposited soil for a tested

reclamation area, an analytical method for self-weight

consolidation of deposited soil, a comparison between

the measured and theoretical results for an indoor

deposition model, and a simple method for predicting

the required volume for a reclamation area.

INTRODUCTION

In the disposal of soft, diluted dredged materials into reclamation areas

using a dredging pump, the relationship between the volume of the dredged soil

and the volume of the reclamation area needed to confine the slurry must be

rectified. This will ensure that the planned height and the actual thickness

of the deposited soil layer after disposal are the same. In estimating the

height of the deposited layer, a number of geotechnical problems remain to be

solved. At present, it does not seem possible to make an acceptable prediction of the thickness of the deposited soil layer (Koba and Miyake 1985).

The following problems have been identified: (a) the phenomenon of

separate deposition in the reclamation area, (b) the method of analysis used

for self-weight consolidation of deposited soil in the continuous deposition

process of soil particles, and (c) the identification of the consolidation

characteristics of deposited zoil in the low-stress region.

In the study of the sedimentation of dredged cohesive soil and the characteristics of the deposited soil, experiments are conducted primarily using

one-dimensional settling containers (Yano, Tsuruya, and Yamauchi 1984; Yano,

Imal, and Tsuruya 1977). A dilute soil-water mixture with the water content

adjusted to a prescribed value is placed in a cylindrical container, the contents are agitated, and settling of the soil particles is observed. From the

ensuing process of self-weight consolidation, the characteristics of consolidation of the deposited soil are determined. While this method has merits--

the experiment is simple and only a small sample is required--it also has

demerits. The phenomena as they occur in an actual reclamation area cannot be

287
correctly reproduced, because the reclamation area allows for expansion in

three dimensions, whereas the model allows only one-dimensional expansion. To

more correctly reproduce the settling state onsite, the study described herein

used a two-dimensional deposition model (Watari, 9iinsha, and Amiboshi 1936).

Terzaghi (1942) made it clear for the first time that the consolidation

phenomenon of clay can be analyzed. During the reclamation of Osaka South

Port, Mikasa (1963) analyzed the consolidation in the cohesive soil formed by

disposal of dredged soil and pointed out that, in analyzing the consolidation

of soft and weak clayey ground, it is necessary to take into consideration:

(a) the influence of self-weight, (b) a nonlinear stress-strain relationship

(the change in the coefficient of permeability with stress), and (c) the

changes in layer thickness. He proposed a consolidation equation that takes

these factors into consideration. Other methods, such as those of Gibson

England, and Hussey (1967) and Monte and Kkizek (1967) have also proposed consolidation equations that take these three factors into consideration. On the

other hand, as a result of the rapid progress of finite element method (FEM)

analysis since its introduction in recent years, it has become possible to

solve the consolidation problem by using a solution to Biot's consolidation

equation (Sandhu 1982; Yokoo, Yamagata, and Nagaoka 1971). In this paper, the

influence of self-weight, the nonlinear relationship between stress-strain,

the change in the coefficient of permeabtlity with stress, and the changes in

layer thickness are investigated using !EM analysis (Watari et al. 1984),

along with a comparison between the analytical and experimental results.

Lastly, a prediction diagram for the thickness of the deposited soil

layer formed by dredging, prepared from the results of the analysis of selfweight consolidation of the deposited soil, is shown, and interpretation of

the diagram is discussed.

SEDIMENTATION AND CONSOLIDATION OF SOIL

PARTICLES IN THE RECLAMATION AREA

When dredged material is disposed in a reclamation area, the result is:

a. Because the dredged soil is diluted with a large volume of seawater

at the dredge suction port and in the discharge pipe, the initial

soil structure of the dredged soil is destroyed, and slurry is created with a water content at the outlet of the discharge pipe ranging

from about 500 to 2,000 percent.

b. When the soil-water slurry is disposed in the reclamation area, it is

again diluted by seawater in the reclamation area, and soil particles

are transported to other parts of the reclamation area by the currents generated from the disposal process.

c. During this transportation process, the soil particles form flocs,

which settle out.

Some sample investigations on actual reclamation areas are described

below. Figure I shows an aerial view of the dredging and reclamation work

conducted in Yanai in Yamaguchi Prefecture. The dredging was conducted in the

anchorage area and the gut area (see Figure 1). The results of preliminary

soil surveys showed that the dredged soil contained a large amount of sand,

288
/Relamation Area

Discharge PiPe

40P""Dred-e 4000ps-A Dredge

Gut. " /00

SOpIiwaY: N,'' 0 10- ,

"'OOps Dredge 0

0 3U ............ 0 Anchorage

* Soil survey .

points 4000ps-B Dredge 0/

'1

Figure 1. Aerial view of dredging and reclamation area

about 60 percent in terms of weight. The total volume of dredged soil was

2,400,000 m3 , and dredging was done with four pump dredges over a period of

about 8 months.

To examine the settlement of soil particles during disposal and the

changes in soil properties resulting from consolidation of the deposited soil,

a stationary floating platform was set up at the four points (A, B, C, and D

in Figure 1) in the reclamation area. Samples were taken at 0.5-m intervals

from the water surface. The water and sand contents of samples from site D

are plotted in Figure 2. For those results where the water content (W) was

higher than 1,000 percent, the turbidity (Tb) was measured and converted into

concentration of suspended solids (SS), and the water content was obtained

from the following equation:

8

W = SS (%) (1)

where y w is the unit weight of water.

The result W < 1,100 percent was obtained by compensating the results

obtained by the drying method (JIS A 1203) (tmai, Tsuruya, and Yano 1979) for

salinity. From Figure 2, a comparison of the point where the water content is

nearest to 1,000 percent and a point 50 cm higher (one measuring point higher)

shows that the water content increases to 105 to 106 percent for a decrease in

depth of only 50 cm, a rapid increase of 1 to 2 orders. In view of the fact

that the condition W < 1,000 percent represents deposited soil and the condition W < 105 percent represents suspension, the deposition surface that

289
IIi . f i li l

• 2 -x l0"...... ......

.2 0 Hach April May 1June Jut Aug. Sep. Oct. Nov.

water content, weiqht (%) 0 Sand Ms (W)

10' I lISIW 10 |IlID U IUU 

10, i *ilflUnI 10' Ul UUUIUit 10. U11 | 11.1 ' 20 40

+ 6 ll~1/14• . . .

"66 U- 5/7l •.- e614w .... ...

- 4 - - . . . wa• ter level 4/2'a T,

2 ---

te

-2

deposit tA6

Figure 2. Measured water and sand contents (at site D)

is the interface between the two conditions should be located in this layer at

a depth of 50 cm. Imai (1980) classified the soil particle settlement in seawater into three categories according to the observations from an indoor settling experiment. These categories are consolidation settling, interface

settling, and flocculated free settling. If this classification is applied,

flocculated free settling is occurring at the present site. This flocculated

free settling is defined as the state in which the clay particles form flocs,

which freely settle without interfering with each other.

As is evident from Figure 2, with the continuous disposal of dredged material, the level of the deposited soil surface rises gradually. On the other

hand, the water content in the deposited soil layer decreases. This decrease

in water content is attributed to the progress of self-weight consolidation.

METHOD OF ANALYSIS FOR CONSOLIDATION OF SOFT CLAY LAYER

Consolidation Analysis

by Finite Element Method

When consolidation of an elastic body in analyzed by FEM, the five basic

equations shown below are used to formulate the finite element.

290
Equation for equilibrium

a (- " h)h) ~ F = 0 (2)

Equation for stress-strain

aoa

a- - E(a') (3)

Equation for strain-displacement

d de = (1 + e) (4)

Equation for void fluid motion (Darcy's law)

k ah v = -az (5)

Equation for assumed continuity

a- = - 3v (6)

TF a z

where

a - total stress

h = water head

z = vertical coordinate in three dimensions

F = weight of unit volume of soil

a' = effective stress

c= strain

E - modulus of elasticity

e = interstitial ratio

v = flow speed of interstitial fluid

k - coefficient of permeability

291
Now to obtain a solution that satisfies basic Equations 2 through 6,

introducing a functional based on the variational principle and rearranging

the equations on the assumption that the first variation of the functional has

a stationary value, we obtain the following equation:

(K)(u) + (C)(h) = (R)

(7)

(C)T(u) + (H)(h) = 0

where

(K) = transformed rigidity matrix

(u) and (h) = node displacement and water head at node, respectively

(C) = coupling matrix

(R) = external force

= = differential with respect to time

(H) = permeability matrix

However, since Equation 7 has a time differential term, it is difficult

to formulate Equation 7 as it is. Hence, integrating the lower Equation 7

with respect to t and using the integral approximation of Equation 8 called

the a - algorithm (Nakanodo 1984), we obtain

t 1

ft h(T)dT = Atfah1 + (1 - a)h0 1 (8)

0

Equation 7 can be rearranged as follows:

T=-u aA~ (9) [; -] aAtH] [ Ct[T Uo + (1 - 1)AtHh

where suffixes 0 and I represent the values when t = t0 and t0 + At

respectively.

When only the self-weight consolidation of clay is considered, the initial water head h at each node occurring due to the self-weight can be

obtained from Equation 10.

292
Y'z

hoi (10)

where

Y; = initial weight of unit volume of submerged clay

zi = depth from ground surface to node i

When this h is obtained prior to the consolidation calculation, and

assuming that an excess water head of ho0 is present in the initial stage,

Equation 9 can be rearranged as follows:

K, C u 1 K,C u 0

CT, _aAtH h CT, (1 - a)AtH h0

The initial (uO) is a null matrix (all elements 0).

Consolidation is calculated as follows. First, (uIV hi) after AtI

is obtained by substituting ( h0 )T at t = 0 into Equation 11. Then,

(U2 , h2 ) at t - At1 + At 2 is obtained by replacing (u1i h at

t = At1 by (u0 ' ho)T . By repeating this replacement in sequence, the total

consolidation process can be obtained. Here, a = I was adopted in the

calculation of consolidation.

Consideration of Nonlinearity

It is known that the stress-strain relationship is not linear (elastic).

In a nonlinear analysis of elasticity, therefore, it is necessary to change

the modulus of elasticity in discrete steps. However, since the way the modulus of elasticity changes during the consolidation process is unknown, in the

present experiment, it was assumed so as to satisfy the conditions of convergence described below.

First, an infinitely small element of finite length Az0 in the clay

layer is considered, and for the initial state, let us assume that the whole

of the clay layer has a uniform interstitial ratio e0 . Then, the excess

interstitial water pressure generated by the self-weight of clay will be disturbed linearly as shown in Figure 3. Next, let us assume that the excess

interstitial water pressure after At hours decreases as shown in Figure 3b,

that it was distributed linearly, and that the quantity of the interstitial

water pressure that dispersed is converted into effective stress. As a

293
0 hrr.

S,-Ab,) r . p*#ApI

aa t

Az~ ~ Pore PO Por ~ a~rrctive

Pru ur Posure atgs e

z fAz.i 0 hi.,.r. (i.,-Ah•.,)r.

(a) initial state (b) At elapsed (Apt -Aht r.) time (Api.,-ahl., -)

Figure 3. Conceptional drawing of the state of consolidation

result, the effective stress will be distributed P + AP at the top end and

P0 + APi+I at the bottom end. This describes clay elements with a uniform

P0 at the initial stage having different stresses after time At . On the

other hand, in consolidation analyses by FEM, the modulus of elasticity Ei(p)

must be constant within the elements. When this Ei (p) is written as Ei(p)

E (p) must be the mean value of the coefficient of elasticity as it varies

with the element.

The linear equation log e - log p is used to represent the relationship

between the void ratio of clay and the effective stress, as described in the

following section:

log e = a + 0 log p (12)

Then, since the modulus of elasticity can be represented by E(p)

(1 + e) dp/de , the following equation will hold:

E(p) E~p) = + e6 e)p (13)

And, let us assume that as a result of giving At and (p) and calculating

the consolidation, the result as shown in Figure 3b was obtained, and that the

settling of this element, SL,i , can be given as the difference between displacement at node i and node i+1.

ASL,i = uI - u +1 (14)

294
In addition, taking the nonlinearity of the stress-strain relationship into

consideration, the settling, ASnonL,i resulting from the increase in the

effective stress of this element can be obtained with reference to Figure 4 as

follows:

z+zoi e e0 - e

AS f e-e dz non-Li z I + e0

where Az0 i dz = -Pidp

Pi+l

Hence,

exp (a/0.4343)Az 0 i P i+0 - 0+

ASnon-L,i 1 + e0 0 L (8+ I)(Pi+1 - P)J (15)

By satisfying the condition ASL,i = ASnon-L,i in the FEM analysis, nonlinearity of the stress-strain relationship can be considered.

0

Figure 4. Conceptional drawing op p9.p..Apa of the state of the £~ effective stress i

hg n rty t t Ps

Change in Permeability with Stress

To calculate consolidation, both the coefficient of permeability and the

modulus of elasticity are needed. Here, the relationship between coefficient

of permeability and stress was assumed to be

log k - b + E log p (16)

Now, supposing that the e - p relationship can be represented by Equation 12

295
and that the coefficient of permeability can be represented by a function of

effective stress, the coefficient of permeability ki(p) forms a pair with

Ei(p) . In other words, if Ei(p) is determined, P can be found from

Equations 12 and 13, and ki(p) can be obtained by substituting this pt

into Equation 16. Here, ki(p) and Ei(P) are taken as a pair.

Changes in Layer Thickness

Changes in layer thickness were considered as follows. Settling of the

element after time t 1 can be obtained by satisfying the equation AS Lj(1)

= AS nonL,(1) in the consolidation calculation in which At is given,

where (1) in AS L,i(1) indicates the first time At 1 was given, and the

decrease in layer thickness was calculated from AZ (1) = AZ 0- AS L,i(1)

In the next consolidation calculation, changes in layer thickness are considered by increasing time At , using the layer thickness after deducting the

consolidation settling.

A flowchart of the consolidation calculation is given as Figure 5, where

START

Soil contets

f .. o.n, a, I

Boundary Cndition U }f Initial ecess h water head. a (0)

Prlumptiof of

I / Elastic Cosolidation

PFi ureption a o l Calculation resumptionflo c an

NO.6

A zi W -A&S -S L. I (L)

Output

A zj W,) f, (L). atLM

Veso.

ED a

Figure 5. Consolidation calculation flowchart

296
H0 represents the initial layer thickness, n is the number of divisions,

f0 = 1 + e0,j (the number of convergence calculations), and i is the number

of consolidation calculations.

MEASURED AND THEORETICAL RESULTS FOR TWO-DIMENSIONAL DEPOSITION MODEL

Deposition Test

To identify the state of sedimentation and deposition of soil particles

in the reclamation area, tests were conducted using the test equipment shown

in Figure 6 and the test conditions described in Table 1.

0 140 cm 400cm

A C D E F G H

I S! I I 25

7 i Cotine (3 x 0' 5 tI

I I

Figure 6. Tes equipment

SI i I i I I I I

L- •140 cm

aate-soil t e Sea dater

I ~1T .1!

Figure 6. Test equipment

The test equipment consists of a 140-cm-diam x 100-cm-high agitating vessel and a 3-cm (W) x 400-cm (L) and 65-cm (H) depositing vessel. The test was

conducted as follows. First, soil and seawater were placed in the agitating

vessel and agitated. Then, in that state, the diluted soil-water mixture was

siphoned into the depositing vessel at a fixed rate. The agitation is continued during siphoning to uniformly distribute particle sizes throughout the depositing vessel. An overflow weir is built into the end of the depositing

vessel to maintain a constant water level in the vessel. The soil sample was

prepared by mixing Tokyo Port clay and Toyoura sand at a dry weight ratio of

6:4.

Case I is continuous flow; in Case II, the diluted soil-water mixture was

agitated for 6 hr and allowed to stand in the container for 18 hr. This cycle

was repeated four times. Toyoura sand was mixed into the sample to examine

separation in the dredged soil deposit, but the results (Watari, Shinsha, and

Amiboshi 1936) are not described in this report.

Figure 7 and Photo 1 show the water content of the upper suspension and

297
TABLE 1. SOIL CHARACTERISTICS AND EXPERIMENTAL CONDITIONS*

WL Clay Silt Sand

s (Z) p (%) (%) (%)

Tokyo port mud 2.60 83.3 43.2 57 35 8

Wo q Disposal

Sample (%) (1/min) Condition

Case I clay;6 1,000 0.712 Continuous

+sand;4

Case II clay;6 1,000 0.700 Separate

+sand ;4

* G - specific gravity of solids, WL = water content at the liquid S

limit, Ip - plasticity index, and q = flow rate.

water content N M

e :urbidiamter s .

25 _ ••-•j••o ---- 0€" :t. •in

Figure 7. Water content distribution (Case I)

settling of soil particles during the siphoning period. The water content in

the suspension showed little change during siphoning, and the deposited soil

and suspension are clearly delineated in the photograph. Figure 8 shows the

deposition during the siphoning period in Cases I and II.

Continuous siphoning of the diluted soil-water mixture increased the

deposition level, with the highest level at the end of the container.

Analytical Method

Where soil particles settle and deposit from the suspension phase, Monte

and Kkizek (1967) proposed the following concept of the critical state. This

concept refers to a phenomenon in which soil is deposited only when soil particles have settled and reached the bottom surface and the effective stress of

the soil is generated. Following this concept of critical state and representing the interstitial ratio in the critical state by e* , the consolidation analysis of continuous deposition of soil particles needs only consider

the case in which the soil in the state of e* deposits continuously and

self-weight consolidation is generated.

298
x 10,

*1 I 0 -

M 3810

o 0 1wo IE

=30 3

20. I

00

x10'

10,x 

1440 "A I90 CM 4620 8 D E F G H

3 0 X6 - In I I

0 ' //Photo 1. State of sedlmenta210 0 H H 20. . tion of soil 0- 

particles

0- 0 Soil deposit 0 (5

b. Case II

Figure 8. State of deposition

The following method was used to obtain the value of e*

a. Assuming the linearity of log e - log p , a linear equation that

coincides well with the results of consolidation test is obtained.

b. Assuming that the initial ei is in a uniform state, the distribution of water content where ei is changed variously is calculated.

c. The results of calculation are compared with the measured result, and

the value of ei closest to the measured result is selected as e*

Figure 9 shows the e and p relationship of the deposited soil in the

e - log p coordinates. In the diagram, effective stress of less than

2 x 10-3 kg (force)(kgf)/cm2 was obtained from the distribution of water

content after self-weight consolidation. That is, the interstitial ratio

e = G W was obtained, and effective stress at the position

i-i

s AZ + 1/2 • Az was obtained from Equation 17. The relationship Ziof e and p was plotted on the diagram.

299
i-i

p(zi) = j Aj + 1/2 Yj Az, (17) iJ-I

The first point near p = 2 x 10-4 kgf/cm2 corresponds to the depth

about I cm from the deposition surface after self-weight consolidation. It

was difficult to obtain the e p relationship in the lower stress region.

12

Tokyo port mud

! hint.D0

I

2 '

10: 10" L 10

effective stress P (kaf/cat)

Figure 9. Interstitial ratio-effective stress relationship diagram

The result 3 x 10-3 < p < 0.5 kgf/cm2 was obtained from the consolidation test using seepage force (Imai 1979), and the result p > 0.5 kgf/cm2 ,

from the standard consolidation t-st. As shown in Figure 9, the e - p relationship of clay covering the low-stress region tends to form a convex curve

on the e - log p coordinates. This relationship is shown in the

log e - log p coordinates in Figure 10. It is considered that an almost

10

. e0 Plog. O 26 -0.1B7logp

10. 10"3 10" 10" 1 10

effective stress p (kaf/cat)

Figure 10. Interstitial ratio-effective stress

relationship diagram

linear relationship holds true for the log e - log p coordinates. Figure 11

is a comparison of measured and calculated results based on water content

after self-weight consolidation at site D. The calculated result in the

diagram shows the value, as illustrated in Figure 12, obtained on the assumption that, at depth z , the initial effective stress of clay (po) that balances the self-weight of clay is zero. The scattered measured results shown

300
in Figure 11 indicate that the measured and calculated results do not satisfactorily coincide. However, with the gradual increase of ei , the calculated values of water content after consolidation differ very little. In the

calculation of consolidation, e* - 16 is used.

void ratio a

• ,.16

Figure 11. Distribution of void 0

ratio after self- 0

weight consolidationD)

(at site D)

0 .easured

o ;calculated 12r

over consolidation

area f- ..... .zH fa excess porepressure t

T z distribution

z

0 (PC) r'H,

(After self-height

(Intial state) consolidation)

Figure 12. Typical drawing of consolidation load

To calculate consolidation, the depositing rate of the clay in state e*

is needed, together with e* , e - p , and k - p relationships. The depositing rate H*/t is obtained from the following equation.

H* -- = n "Qs 1 + e* (18)

t A.t*I+e

where

H* = height of the deposited soil in state e*

n = volume compensation for separately depositing sand

Qs = volume of diluted soil-water mixture siphoned over t hours

A = depositing area of clay

e = interstitial ratio of dilute soil-water mixture

301
Comparison Between

Measured and Analytical Results

With respect to site D of the two-dimensional deposition test, soil

constants are arranged as follows. For the k - p relationship, the

effective stress is obtained in the range of p > 4 x 10-3 kgf/cm2 only, as

shown in Figure 13. This equation of relationship is extended to the

low-stress region.

"* Interstitial ratio in critical state, e* - 16

"* Equation for e - p relationship, log e - 0.268 - 0.187 log p

(p, kgf/cm2 )

"* Equation for k - p relationship, log k = -5.333 - 0.796 log p

(k, cm/min)

"* Depositing rate, Case I, H*ft - 1.45 cm/hr

Case II, H*/t = 1.75 cm/hr

Point. D

'a.

i0.' 0

I0" 1 0 -- 10" 1 LO

effective stress p (gf/ce')

Figure 13. Coefficient of permeability-effective

stress relationship diagram

Figure 14 is a comparison between measured values and analytical values

for the increasing process of the deposited soil thickness during the disposal

period and the ensuing sedimentation with respect to Cases I ant II at site D.

In the finite element analysis, the deposition height AH* for

At - 60 min was calculated on the assumption that the dredged soil is

deposited for 5 min followed by standing for 55 min. Continuous deposition

was calculated on the assumption that this cycle of operation continued. In

the element-division of AH* , n = 5 was used, and the analysis was conducted on the assumption that the total number of elements will increase as

clay deposition progresses. As shown in Figure 14, in both Case I and

Case II, the measured and calculated results of the process of deposition

thickening during the disposal period and the ensuing settling agree very

302
Tokr sort ned

Ptett. 0

o measured -: calculated

-0 a •I'l•~.

10

0

0 I 1| J I II II1|l Ii, IIIIII I I

10 to0 10, 101

elapsed tie t (ale)

Toky port med

Foist. D

0 mSe~asued calculated

20 e." 16 8 A H'1.7lSce/hor

100

to o0' i0o tO to0

elapsed tin t bmi)

Figure 14. Comparison between experimental and

analytical results (Case I)

well. Figure 15 shows, for example, the changes in interstitial ratio in the

deposited soil layer with time and the dispersion process of excess interstitial water pressure (calculated result) in Case I.

PRFDICTION OF HEIGHT OF DEPOSITED SOIL LAYER

Figure 16 shows the relationship between the volume of dredged material

and the volume of the reclamation area. The parameters needed for drafting a

dredging and reclamation plan are listed below.

Dredging area -- Total volume of dredged soil, VD f AD * zD

Mean interstitial ratio of dredging area, eD

Reclamation area -- Area, AR ; planned deposition height, HR

Other -- Dredging period, tD

303
Void ratio e Excess pore pressure T.-h ( xlO--Kig/cm/ )

6 . I 8 I I 10 . . 12 I= . 14 I I 16 0 I i ý I I 1 I . I I 2 I1

26.3 m1_2m (-31.7 )•

..... ; Dumping period

2 (64. 3) -- Rest period 2M0 0 (64.3)

202

(89.8) S7200 7200 (89.8)

14300 (98.0) 14300 (98.0)

2- , - 720

/ /

S . t00

Figure 15. Changes in interstitial ratio and excess interstitial

water pressure over time (Case I)

(Dredging si te) , ,-. _ (Reclamation site)

;Ao Period : to E Area ;Aa SArea 

L Dredging depth zo L. Planing height of

soil deposit :Hi

Discharge pipe Soil-wafer mixture

Pump-.dredger - ;. (.-., U-/0 ,.,)

ratio e

""__ Soil deposit

Dredid soils / zo Average void ratio Clayey soils _LL, .... '_/

Figure 16. Conceptional drawing of relationship of dredged

material volume and reclamation area volume

When the total volume of dredged material VD is dredged and deposited

in the reclamation area, if the deposition height H (t D) in the reclamation

area coincides with HR after disposal of the total volume of dredged soil,

the most ideal dredging and reclamation conditions have been met.

The deposition heights during continuous disposal of dredged cohesive

304
soil were calculated by the FEM at various depositing rates, H*/t . The FEM

results are shown in Figure 17. Tokyo Port clay was used as the soil constant. The diagram can be used as follows.

a. First, the total soil height that will deposit per unit area in state

e* in the reclamation area is obtained by

= VD (I + e*) AR(I + eD)

When the total soil height H* and H corresponding to the disposal

rate H*/tD are obtained from Figure 17, this H corresponds to the

soil deposition height H (tD). 'C7

=H W

H" Cm)

Figure 17. Prediction of deposition

(Tokyo Port clay)

b. To dispose H* into the reclamation area to height HR , H ( HR)

and H*/t corresponding to H* can be used for the disposal rate.

However, when H and the point corresponding to H* are located at

a position below and right of the state after self-weight consolidation shown as H*/t - 1/- , it is not possible to dispose the total

volume of dredged soil into the reclamation area.

c. Wien HR , AR , and H*/tD are set up, the dredged soil volume VD

that can be disposed into the reclamation area can be obtained by

reading HR and H* corresponding to H*/tD and substituting this

H* into Equation 19.

Also, according to Figure 17, when H is assumed as 3 m and H*/t is

changed, H* becomes 7.2, 12.8, and 23.1 m where H*/t is 40 cm/day,

10 cm/day, and I/- , respectively. This shows that the slower the dredged

305
material is disposed, the faster self-weight consolidation of the deposited

soil layer progresses, making it possible to dispose more dredged material in

the reclamation land.

CONCLUSIONS

This paper described the state of sedimentation of soil particles and the

state of consolidation of deposited soil for an actual reclamation area, and

discussed a method for predicting of deposited soil layer thickness of dredged

cohesive soil which the authors have studied for years. Specifically, an

analytical method of self-weight consolidation, experimental verification of

the analytical results, and a simple method for predicting deposited soil

layer thickness are described. For the self-weight consolidation analysis of

the deposited soil, the concept of critical state, proposed by Monte and

Kkizek (1967), was used. It was then necessary to calculate consolidation

from a very low-stress condition, and more detailed study is needed on the

consolidation characteristics of the clay in the ultralow-stress region. In

this regard, it is particularly important to evaluate the coefficient of permeability in the range of p < 5 x 10-3 kgf/cm2 . As to the prediction of

deposited soil layer thickness shown in Figure 17, it is regrettable that

there is no example in which analytical results are compared with reclamation

site data. Further analysis of the site data and study of a prediction method

closely based on reality are required.

ACKNOWLEDGMENTS

The authors would like to express appreciation to Mr. Ryoya Yamaguchi for

help with the indoor experiments and Mr. Yasushi Takano for the analyses and

arrangements of diagrams.

REFERENCES

Gibson, R. E., England, G. L. and Hussey, M. J. L. 1967. "Theory of OneDimensional Consolidation of Clays," Geotechniques, Vol 32, No. 5, pp 28-28.

Imai, G. 1979. "Development of New Consolidation Test Procedure Using Seepage Force," Soil and Foundations, Vol 19, No. 3, pp 45-60.

Imai, G. 1980. "Settling Behavior of Clay Suspension," Soil and Foundations,

Vol 20, No. 2, pp 61-77.

Imai, G., Tsuruya, K., and Yano, K. 1979. "A Treatment of Salinity in Water

Content Determination of Very Soft Clays," Soil and Foundations, Vol 19,

No. 3, pp 84-89.

Koba, H., and Miyake, M. 1985. "Partial Review of Dredged Material Disposal

Techniques," Management of Bottom Sediments Containing Toxic Substances, Proceedings of the 10th U.S./Japan Experts Meeting, T. R. Patin, ed., US Army

Corps of Engineers, Water Resources Support Center, pp 222-236.

Mikasa, M. 1963. "Consolidation of Soft and Diluted Clay," Kashima Shuppan

Kai.

306
Monte, J. L., and Kkizek, R. J. 1967. "One-Dimensional Mathematical Model

for Large-Strain Consolidation," Geotechniques, Vol 26, No. 3, pp 495-510.

Nakanodo, H. 1984. "Application of Finite Element Method to Ground and Foundation Engineering and Aseismic Engineering," Proceedings of Chushikoku Branch

Meeting of Doboku Gakkai, pp 1-10.

Sandhu, R. S. 1982. "Finite Element Analysis of Coupled Deformation and

Fluid Flow in Porous Media," Numerical Methods in Geomechanics, Proceedings,

NATO Advanced Study Institute, pp 203-277.

Terzaghi, K. 1942. Theoretical Soil Mechanics, John Wiley and Sons, Inc.,

New York, N. Y.

Watari, Y., Higuchi, Shinsha, H., and Hamasaki. 1984. "One-Dimensional Consolidation Analysis by Finite Element Method," Annual Report of Technical Research Laboratory, Penta-Ocean Construction Co., Ltd., Vol 13, pp 89-97.

Watari, Y., Shinsha, H., and Amiboshi. 1936. "Sedimentation and Separate

Deposition of Dredged Cohesive Soil," Study Report by Faculty of Engineering,

Hiroshima University, Vol 34, No. 2, pp 175-187.

Yano, Imai, and Tsuruya. 1977. "Nendo no Chinko Jikken," Proceedings of the

12th Geotechnical Meeting, pp 231-234.

Yano, Tsuruya, and Yamauchi. 1984. "Separate Deposition of Dredged Cohesive

Soil," Tsuchi To Kiso, Vol 32, No. 5, pp 23-28.

Yokoo, Y., Yamagata, K., and Nagaoka, H. 1971. "Finite Element Method Applied to Biot's Consolidation Theory," Soils and Foundations, Vol 11, No. 1,

pp 29-46.

307
INVESTIGATIONS OF SUBAQUEOUS BORROW PITS AS DISPOSAL SITES FOR

CONTAMINATED DREDGED MATERIAL FROM NEW YORK HARBOR

.. .J. F. Tavolaro and M. A. Paula

""• US Army Engineer District, New York

Operations Division

26 Federal Plaza

New York, New York 10278-0090

R. M. Cerrato

Marine Sciences Research Center

State University of New York

Stony Brook, New York 11794

ABSTRACT

Past underwater sand mining has left many large

depressions, called subaqueous borrow pits, on the

floor of the Lower Bay of New York Harbor. Research

has shown that borrow pits are natural "sinks" for

contaminant-laden sediment and that they contain

stressed benthic communities different from those

found in nonpit areas. The disposal and capping of

contaminated dredged material into borrow pits would

obviate possible impacts at the ocean disposal site

while reclaiming lost portions of the sandy bottom of

New York Harbor. A demonstration project to prove the

feasibility of borrow pit disposal was begun by the

New York District (NYD). The project was not completed because of litigation, although research in

other parts of the country showed that borrow pit disposal was technically feasible. Based on this information, the NYD is implementing an operational program

for dredged material disposal into existing or new

borrow pits. A Federal EIS is being prepared. A sediment characterization scheme has been developed to

determine material eligible for borrow pit disposal.

Evaluative criteria, based on physical and biological

criteria, were used to rank existing pits in order of

preference. Similar criteria were used to determine

the areas in the Lower Bay that would be adequate for

excavation of a new pit. A monitoring/management program is being developed to ensure that disposal operations in borrow pits are properly implemented without

adverse impacts.

BACKGROUND

The floor of the Lower Bay of New York Harbor is composed predominantly

of sand and gravel that were deposited as the last glaciers receded from this

area about 18,000 years ago. It has been estimated that the surficial sand

308
deposits under the Lower Bay alone have a total volume of about 2.6 billion

cubic meters (Bokuniewicz, Cerrato, and Hirschberg 1986). Over the past several decades, sand and gravel have been mined from the floor of the Bay for

use as construction aggregate and fill. Between 1950 and 1980, more than

32 million cubic meters of sand and gravel was dredged from the Bay

(Bokuniewicz, Cerrato, and Hirschberg 1986). This mining activity has produced a number of subaqueous borrow pits of varying size and depth. The principal ones are shown in Figure 1.

Since 1973, sand mining activity in the Lower Bay has been restricted

primarily by environmental concerns, and over the past decade a number of

studies have been conducted to address those concerns. For example, some

authors used mathematical models of the waves and tides to examine whether the

borrow pits affected beach erosion (Kinsman et al. 1979, Wong and Wilson

1979). Their results indicated that the pits were large enough to noticeably

affect the waves and tides. Both the tidal range and the wave energy reaching

the shore were slightly increased by the presence of the pits. These changes

would tend to aggravate shoreline erosion although the magnitude of the impact

was considered small and difficult to assess.

A second concern arose from the fact that the pits on the West Bank were

natural traps for mud. Little or no mud is deposited on the sandy bay floor

around the pits, but in them, mud was accumulating at rates between 4 and

9 cm/year, or about 100 times faster than typical natural rates in other estuaries (Bokuniewicz, Cerrato, and Hirschberg 1986). The presence of the pits

has changed about 1,053 acres (426 ha) of the seafloor from sand to mud. In

fact, if mud continues to accumulate in pits as rapidly as it has over the

past 10 years, the pits will completely fill within 50 to 100 years. Because

of the affinity of many contaminants for fine-grained sediments, the pits are

also sinks for contaminants in the Lower Bay (Benniger, Lewis, and Turekian

1975).

The mud accumulating naturally in the pits on the West Bank has a high

organic content, and there was concern that the degradation of this organic

matter would deplete the oxygen in the bottom water during the summer. In

1978, measurements showed that the pits on the West Bank did affect the oxygen

demand, and lower oxygen concentrations were found there when compared with

sandy shallow areas (Swartz and Brinkhuis 1978). Dissolved oxygen concentrations low enough to stress animals (<3.5 ml/f) were observed near the bottom

of the pits on several occasions (Conover, Cerrato, and Bokuniewicz 1985; National Marine Fisheries Service 1984; Swartz and Brinkhuis 1978).

Since the physical environment in the borrow pits differed substantially

from the ambient seafloor, an additional concern was the effect of the pits on

the community structure of the benthos within and adjacent to them. To address this concern, a seasonal benthic study was conducted between July 1980

and June 1983 (Cerrato and Scheier 1984). Results indicated that the fauna in

borrow pits were distinctly different from the ambient seafloor in terms of

species composition and in temporal patterns of abundance, species richness,

diversity, and equitability. The fauna within the borrow pits were dominated

by opportunistic species and were characterized by very large seasonal changes

in abundance and species richness (Figure 2). Extremely low abundances generally occurred during the warmer months, suggesting oxygen stress as a possible

cause for the observed pattern. In contrast, the benthic fauna at a control

309
Ad

to 0

ca

Ar

* it 0

* 0

144

310
.ocz

100

16 1

1979 166 166.3

U UMt+ central

a. Average abundance (per square meter)

14

12 2

11

to

9 9

7

3 S

2

0-

1979 1681 163

" Seer " P+ 4

b. Average number of species (per sample)

Figure 2. Comparison of benthic abundance and species

richness at a borrow pit on the West Bank and

at a control area approximately 2 km southwest

311
area were more stable and diverse over time. Evidence was also found that the

borrow pits affected the structure of the benthos at locations close to the

pits.

Given the documented impacts of existing borrow pits, filling them and

reclaiming the sandy seafloor would appear to be a desirable goal. Even the

smallest suitable pit, however, has a capacity of over 1.5 million cubic meters, and the total capacity of pits on the West Bank alone exceeds 19 million

cubic meters. The cost of filling these pits would be prohibitive unless a

source of free material is available. Dredged material can provide that material and, in addition, burying dredged sediment in subaqueous borrow pits has

its own advantages. Most of the dredged material from New York Harbor is

contaminated by agricultural, urban, or industrial products. Whatever the

disposal technique used, it is desirable that the material be contained in a

disposal site and isolated from the marine environment to the greatest possible extent. Subaqueous pits are attractive containment sites because mud is

accumulating in them at very rapid rates, and the pit walls are sufficiently

steep to limit the spread of dredged sediment during discharge (Bokuniewicz

1979). If the dredged material is deposited in the pit and covered, or

capped, then not only could the Bay floor be restored to its premined condition, but the dredged mud could also be buried beyond reach of most burrowing

animals and beyond the depth of disturbance by storm waves (Bokuniewicz,

Cerrato, and Mitchell 1981). Burial keeps the mud in a reduced state so that

particle-bound contaminants are unlikely to migrate. Burial in the pits also

eliminates problems of ground-water contamination that may be a concern with

landfill operations.

DEMONSTRATION PROJECT AND LITIGATION

Present investigations into the feasibility of using borrow pits for the

disposal of dredged material began in 1979. Borrow pits were identified as

possible sites for the disposal of large quantities of dredged material and,

in special cases, for highly contaminated dredged material (Connor et al.

1979). For this reason, investigations of borrow pits were included in the

Dredged Material Disposal Management Plan for the Port of New York and New

Jersey, which also investigated other disposal alternatives such as containment

facilities and upland disposal for dredged material (Coch et al. 1983,

Suszkowski and Mansky 1981, Tavolaro and Zammit 1986).

In 1980, at the request of the New York District, the Marine Sciences Research Center of the State University of New York, Stony Brook (SUNY), began

site-specific research on use of borrow pits. They identified 10 questions

that needed to be addressed to determine if borrow pit disposal was feasible

in New York Harbor, concerning the physical aspects of the creation of the

deposit and the physical, chemical and biological integrity of the cap

(Bokuniewicz, Cerrato, and Hirschberg 1986). Later, two additional questions

were raised concerning gas generation within the deposit, potentially disrupting the cap, and the value of borrow pits to finfish populations of the Lower

Bay.

Relevant literature was summarized, site-specific environmental information was obtained from representative borrow pits, and dredged material disposal modeling was performed. All indications were that borrow pit disposal

with capping appeared to be feasible and practicable. However, to determine

312
if borrow pits could be used on an operational basis, a demonstration project

was the next logical step. The demonstration project involved disposing

dredged material into one small portion of an existing borrow pit offshore of

Staten Island, NY, capping it, and monitoring the deposit for 6 months to determine the environmental impacts (Mansky 1984). Since this borrow pit was

very large, the demonstration project was designed as a three-phase operation

to isolate its southern tip for the experiment. Phase I would be the construction of a sand berm to isolate the southern tip, Phase II would be the

disposal of the dredged material behind that berm, and Phase III would be the

sand cap over the entire deposit (Figure 3).

The Phase I berm was successfully placed in December 1981 by the Corps of

Engineers Dredge GOETHALS. Approximately 167,000 m3 of sand dredged from

Ambrose Channel was used for berm construction. This left a disposal area

behind the berm that was 200 m in diameter and 14 m deep. Before Phase II

could begin, a local Staten Island conservation group, the Natural Resources

Protective Association (NRPA) interceded. They strongly opposed the demonstration project because they considered the borrow pit to be in a prime recreational fishing area. They gathered a large amount of public support for

their cause and enlisted the aid of their local US Congressmen and State

elected officials to raise concerns to both the State regulatory agencies and

the NYD. They so strongly opposed the demonstration project that they sued

the State of New York for issuing a Section 401 Water Quality Certification

for the project.

Specifically, their lawsuit stated three causes of action:

a. An environmental impact statement (EIS) was not submitted, which they

felt was necessary to fully address the environmental impacts of the

project.

b. The project was not reviewed under the State Coastal Zone Management

Program policies (at the time, the New York State program was not yet

in full effect).

c. Ocean disposal testing criteria, which were used to evaluate dredged

material for disposal in the borrow pit, were not felt to be stringent enough in such a highly utilized sport fishing area as the Lower

Bay.

A temporary injunction caused delays while the issues were argued in

court. The State of New York Supreme Court, Richmond County (Staten Island),

decided that there was enough "disparity of scientific opinion" to "hold these

motions in abeyance" until a neutral scientific panel "mutually selected by

the parties" determined the impacts of the demonstration project and reported

to the court. New York State appealed the decision, but the Appeals Court

ruled that it was not "appealable" because a decision had not been rendered,

but merely delayed until the scientific panel had made its report. Efforts by

the State to assemble a scientific panel acceptable to both parties failed,

further delaying the demonstration project.

Meanwhile, fisheries surveys of borrow pits in New York Harbor had been

funded by the NYD to determine in detail the resource potentially being

affected by the demonstration project. The first surveys were performed by

313
2(;

40

60 2u

MAIN SHIP CHANNEL

PROPOSED A cp

BERM

401

.10

20 C 11

o 1800'

a. Plan view of borrow pit (depth contours in feet)

-_0i

-20, EXISTING BOTTOM

- 30

OEPTt4 FT 4

-50

A PHASE I COMPLETION A'

.10.

-20 "EXISTING BOTTOM

O•EPTH. F T -. 40,1,, .,,.-, l

-50

A PHASE I1 AND III COMPLETION A

b. Cross section A-A' (1 in. = 400 ft)

Figure 3. Proposed borrow pit demonstration project

314
the National Marine Fisheries Service (NMFS) and SUNY, comparing the fisheries

characteristics of two representative borrow pits with an undisturbed sandbottomed control area (Conover, Cerrato, and Bokuniewicz 1985; Pacheco 1983).

The same sampling locations were covered by both groups for a 1-year period,

with each group using slightly different trawling equipment. The NMFS study

used an unlined trawl to catch only adult populations of fish that would appeal to recreational fishermen. The SUNY study used a 65-mm cod-end liner to

catch juveniles and smaller species. Both studies showed that although borrow

pits did not support permanent fish populations and were not an important food

source for migratory species, they did tend to congregate fish in higher numbers than the surrounding flat, sandy bottom for most of the year.

These results led us to look into the matter further and expand the fisheries surveys to include more than just the three previously sampled areas.

Another year-long survey was initiated (NMFS 1984) to consider fish occurrence

in eight locations, including other borrow pits, navigation channels, shoal

areas, and flat sandy and muddy bottoms. This study further reinforced the

previous conclusion that borrow pits do not support permanent or unique fisheries resources in the Lower Bay. Further analysis of all fisheries surveys

showed that two types of stations were represented by the sampling, i.e.,

shallow sand-bottomed (Group I) and deeper, mud-bottomed (Group II). Group I

stations were generally lower than Group II stations in terms of catch, number

of species, and weight of species, but there were apparently no significant

differences between stations included in each Group (Bokuniewicz, Cerrato, and

Hirschberg 1986).

Based on this neu information, the State of New York revoked the Section 401 Certification for the demonstration project, despite our protests.

This revocation made the lawsuit a moot issue, therefore resolving it. The

NYD reapplied for a Section 401 Certification, this time submitting the recently completed fisheries studies at the State's request as "new and relevant" information. They decided that a State EIS was required (previously it

was not) pursuant to the New York State Environmental Quality Review Act. It

should be noted that the lack of an EIS was one of the litigant's original

complaints. The NYD began preparing a State EIS for the demonstration

project.

Meanwhile, other pertinent research on the effectiveness of capping and

borrow pit disposal had been completed (Brannon et al. 1985, 1986; Sumeri

1984; Truitt 1986). The NYD realized that the demonstration project as

planned was no longer necessary. The questions it was designed to answer had

already been answered, and the results showed that borrow pit disposal could

be done effectively. The NYD suggested that all parties work toward developing an operational program of borrow pit disposal, selecting an existing pit

or an area environmentally suitable for construction of a new borrow pit, or

both. Surprisingly, both the State of New York and the NRPA agreed to work

with the NYD toward this end. The NRPA stated that they were not opposed to

borrow pit disposal, in principle, but were mainly concerned that the site

ultimately chosen for disposal be acceptable from their perspective. They

also believed that existing pits are "productive," and only new pit sites

should be explored.

The NYD withdrew the Section 401 Certification application for the demonstration project, applied for new certification for an operational program,

315
and proceeded to prepare a Federal EIS on borrow pit disposal. The State of

New York agreed to overlap the respective regulatory processes to the maximum

extent possible, with the ultimate intent of granting a Section 401 Certification for use of the disposal site selected for an operational program (assuming that a suitable site could be found).

SUBAQUEOUS BORROW PIT FEDERAL EIS

The NMFS, the US Environmental Protection Agency (EPA), the New York

State Coastal Management Program, and the New Jersey Department of Environmental Protection all agreed to be cooperating agencies on the EIS, which is now

in preparation. Although the US Fish and Wildlife Service is not a cooperating agency, it has expressed general support for the project. The NYD is continuing to coordinate will all parties, including Staten Island Federal and

State elected officials, who continue to remain interested in the effect of

the project on their constituents.

The document is to be released as a Supplemental EIS (SEIS) to the 1983

Dredged Material Disposal Alternatives EIS prepared by the NYD (US Army Engineer District, New York 1983, 1987). The 1983 EIS evaluated all possible alternatives for dredged material disposal for the Port of New York and New

Jersey. One of the conclusions of the Alternatives EIS was that subaqueous

borrow pits are the preferred alternative for the disposal of contaminated

dredged material that exhibits potential for toxicity or bioaccumulation.

The goal of the borrow pit Federal SEIS process is to obtain all necessary regulatory approvals for implementation of an operational program for the

disposal of dredged material from the Port of New York and New Jersey into

subaqueous borrow pits. The SEIS is a site-designation document with the anticipated result being the authorization to use an existing borrow pit and/or

to construct a new pit to be used as a disposal site.

Sediment Characterization

A characterization scheme for the types of sediment that would be deposited was developed based on the standard bioassay/bioaccumulation tests required by the Ocean Dumping Testing Criteria for dredged material (EPA/CE

1977). Category I material has acceptable toxicity and bioaccumulation effects on tested marine organisms and would not be considered for borrow pit

disposal. These sediments are considered suitable for unrestricted ocean disposal. Placement of a sand cap over them to prevent adverse environmental impacts to the marine environment would not be necessary. Category II sediments

have some toxicity or bioaccumulation effects and would not be considered for

unrestricted ocean disposal. Presently, Category IT sediments can be disposed

in the ocean, provided they are expeditiously capped to protect against adverse impacts. Category IT sediments would be candidates for borrow pit disposal. Category III sediments have unacceptable toxicity or bioaccumulation

effects and do not meet the Ocean Dumping Testing Criteria. These sediments

would not be considered for ocean disposal but would be candidates for borrow

pit disposal. In summary, sediments of Categories TI and III would be considered for borrow pit disposal, while Category I sediment would be disposed

in the ocean.

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After developing the sediment characterization scheme, the next task was

to estimate the approximate volume of dredged material per year that woIld be

eligible for borrow pit disposal. This yearly average would be used to compute the pit capacity needed for a suitable long-term (10 years) disposal

site. Data from the development of the currently used Ocean Dumping Testing

Criteria (1980 to the present) were reviewed to calculate what percentage of

dredged material required capping. It was determined that approximately

7 percent of the dredged material deposited in the ocean disposal site since

1980 required capping. This amounted to nearly 1,760,000 m3 of dredged material. Adding another 135,000 m3 of material that was not allowed to be disposed of in the ocean during this time gives a total of approxirately

1,900,000 m3 that would have been eligible for borrow pit disposal. Possible

increases in the volume of dredged material that would not meet the criteria

for unrestricted ocean disposal, as well as additional amounts of dredged material that may be needed for use as interim caps, increases the volume requirements of a borrow pit disposal site. Taking into consideration the

yearly average of the above, as well as modifications to the Testing Criteria

that could increase that average and the possibility of interim caps, it was

determined that a borrow pit disposal site should have a minimum capacity of

3,000,000 m3 .

Evaluative Criteria

for Existing Borrow Pits

The first consideration in evaluating borrow pits in lower New York Harbor is that the pit meet the minimum physical requirements for retention of

the deposited dredged material (Wong and Wilson 1979). These requirements include a minimum water depth to the ambient bottom of at least 5.5 m, and a

minimum pit radius of 228 m. The depth requirement is to prevent erosion of

the deposited sediment by wave action. The minimum radius requirement takes

into consideration average barge size, water depth, the character of the sediment, the slope of the pit walls, and the dynamics of the bottom surge as it

'aukes contact with the pit bottom and spreads outward. Of the 20 existing

pits identified in lower New York Harbor and adjacent areas, only seven pits

(Nos. 2, 3, 4, 6, 7, 14, and 15) meet the minimum requirements (see Figure 4).

Three of these pits (Nos. 2, 3, and 4) are in the West Bank area of lower New

York Harbor, two (Nos. 6 and 7) are in the East Bank area of the Harbor, and

the remaining two (Nos. 14 and 15) are in Jamaica Bay, a body of water east of

the Harbor.

The seven existing borrow pits that passed the minimum criteria were then

evaluated by using physical and biological criteria to qualitatively rank them

in order of preference as a disposal site. The physical criteria included the

following factors:

a. Pit size and depth--adequate volume to be a long-term dredged material disposal site. One of the Jamaica Bay pits (No. 14) has the

largest capacity, followed by the two pits on the East Bank.

b. Erosion potential--the location of a given pit in relation to wave

and current action, which would affect the stability of disposed material. Jamaica Bay pits, being in a sheltered body water, would

have the greatest protection from erosional effects.

317
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c. Need for modifications--the degree to which a pit would require

physical modification, such as the need to dredge and maintain access

channels from main channels to the pit site. Pits 4 (West Bank)

and 6 and 7 (East Bank) would need the least amount of modification.

d. Water quality impacts--the short-term impacts associated with dispersion of suspended material during disposal operations. Projections of suspended material plumes and hydrographic conditions at

given pit locations were evaluated. The most exposed pit (No. 7)

would be the best suited to disperse and dilute the suspended material plume resulting from disposal operations.

e. Conflicting uses--possible conflicts in the use of certain pits as

disposal sites, which may contravene planned uses of the areas in

which the pits are located. For example, the East Bank pits are located in an area that has been designated as a possible sand-mining

area by the State of New York. A borrow pit disposal site in this

area may create a conflict with the sand-mining activities.

The biological criteria were developed to compare and rank the pits to

determine which pits would have the least biological constraints for use as a

disposal site. The biological criteria included the following factors:

a. Benthic impacts. The possible effects of borrow pit disposal on

benthic communities within and adjacent to pits were evaluated using

existing data (Bokuniewicz, Cerrato, and Hirschberg 1986; Cerrato

and Scheier 1984; McGrath 1974), as well as the preliminary results

of an extensive benthic survey of lower New York Harbor funded by

the NYD (Cerrato, Bokuniewicz, and Ellsworth, in press). These

studies suggest that pits on the West Bank of the Harbor generally

contain stressed benthic communities with low diversity and fairly

low abundances, as compared with the East Bank pits, which were generally characterized by high benthic abundances and diversity. The

pits in Jamaica Bay were also determined to have a poorer benthic

community as compared with the East Bank pit community.

b. Fishery impacts. The use of existing borrow pits by fishery resources in lower New York Harbor was evaluated by using past studies

of borrow pit areas (Conover, Cerrato, and Bokuniewicz 1985; NMFS

1984; Pacheco 1983), as well as a new comprehensive fishery study of

the Lower Harbor (Woodhead and McCafferty 1986). Among all the existing pits, the Jamaica Bay pits were determined to have the lowest

value of fishery resources, and would be most preferable as disposal

areas from a fisheries standpoint. The West Bank pits had a higher

fisheries value than the Jamaica Bay pits, and the East Bank pits

were found to have the highest value of all the pits evaluated.

c. Wildlife/wetlands impacts. The only existing pit sites where this

would be a concern would be the two pits in Jamaica Bay, which has

extensive wetland areas and is a migratory stopover for waterfowl.

Combining the rankings of the biological and physical criteria, pit 4 on

the West Bank, which was used in the demonstration project, was determined to

be the most preferred disposal site. This pit would have the least physical

319
and biological constraints of the existing pits evaluated. The two large

Jamaica Bay pits (Nos. 14 and 15) would be next on the preferred list, followed by the large West Bank pit (No. 3) and the large East Bank pit (No. 6).

It should be noted, however, that these five pits are very closely ranked, so

the differences in preference are not great. The remaining smaller pits are

ranked similarly and are the least preferred.

Evaluate Criteria

for New Borrow Pits

Criteria were also developed to evaluate locations for the construction

of new borrow pits. One purpose of constructing a new borrow pit would be to

avoid possible impacts to biological communities in and around existing pit

sites. Further, new pit construction allows for the specific design of a pit

as a dredged material disposal site, which provides operational advantages to

using an existing pit site. A negative impact of new pit construction would

be the disturbance of a previously undisturbed portion of the lower New York

Harbor bottom, which could affect the benthic and fisheries communities in and

around the site. To lessen these possible impacts, new pit sites should

ideally be chosen in areas of low biological use and productivity. Moreover,

new pits must be in areas that have usable sand or gravel deposits to avoid a

disposal problem that would result from constructing a pit in mud-bottom

areas. The sand or gravel deposits could be excavated by private concerns,

who would be allowed to keep the material in return for excavation of the pit.

Another consideration for construction of a new pit is that no existing cultural or archeological resources, such as sunken ships, be disturbed. This is

not a concern in using existing pits because, presumably, any cultural or archeological resources were disturbed during the original sand-mining operations that created the pits.

The first step in determining new borrow pit disposal sites was the evaluation of four areas in lower New York Bay suggested by the environmental

groups (New York Bight Restoration Group 1984) affiliated with the Dredged

Material Disposal Management Plan for the Port of New York and New Jersey.

This evaluation was based on their review of existing biological and hydrographic data and information from recreational and commercial fishermen in the

area.

Criteria based on physical and biological factors were then developed to

determine which proposed new pit areas uld have the fewest constraints as an

operational borrow pit disposal site. The physical criteria for new pit sites

were:

a. The suitability of the sediment type for use as construction-grade

sand or gravel. A previous survey shows several types of sediments

in the Lower Bay suitable for use in construction activities, with

the East and West Bank areas containing the greatest amounts of these

types of material (Kastens, Fray, and Schubel 1978).

b. Water depth and hydrological regime. The new pit site should not be

situated in water too shallow to allow the safe navigation of disposal barges nor be subject to wave disturbance that could disrupt

320
the deposited dredged material. The new site should not be situated

in an area of extreme water depths that could cause operational

problems.

c. Shore erosion effects from the construction of a new borrow pit.

Mathematical models (Wong and Wilson 1979) were evaluated to determine if new pit construction in the Lower Bay could affect the rate

of shoreline erosion in adjacent areas, such as Staten and Coney

Islands. It was determined that any erosional impacts would be

minor, but construction of a new pit on the West Bank of the Lower

Bay would be preferable.

Based on the physical criteria for the construction of new borrow pits,

areas in both the East and West Banks appear similar in preference, with East

Bank areas having deeper sand deposits with a range of construction uses but

also a greater possibility of shoreline erosion. The biological criteria for

new site selection consisted of the following:

a. Benthic criteria. Existing data (Cerrato, Bokuniewicz, and

Ellsworth, in press; McGrath 1974) were used to identify areas of

low benthic abundance and diversity.

b. Fishery criteria. Recent fishery surveys of the Lower Bay (Woodhead

and McCafferty 1986), coupled with previously mentioned existing

fishery data (Conover, Cerrato, and Bokuniewicz 1985; Pacheco 1983),

were used to identify areas of low fish usage.

Based on the combined benthic-fisheries criteria, it was determined that

the most preferred new pit sites (the sites with the lowest biological use)

are in the East Bank and in northeast Raritan Bay (Figure 4).

After considering both the physical and biological criteria, it was determined that an area approximately 1 by 2 km in the East Bank adjacent to

Ambrose Channel is the most preferred area for siting a new pit (Figure 4).

This is an area of comparatively low benthic abundance and diversity and fishery usage. Further, it has ample construction-grade sand resources that would

be attractive to sand-mining interests. The next preferred site is an area

4.5 by I km in Raritan Bay (the "NE Raritan Bay" site in Figure 4). It should

be noted that these two proposed pit areas are large tracts, and any new pit

would occupy only a small portion of an area.

To comply with existing regulations protecting marine archeological and

cultural resources, a remote sensing survey of the two proposed pit areas is

being done to ensure that undocumented resources would not be destroyed during

construction of a new pit. If archaeological resources are identified, the location of the proposed pit could be shifted to other sections within the new

pit areas to avoid impacts.

MONITORING AND MANAGEMENT

A monitoring and management plan is being developed by the NYD to ensure

that disposal operations in borrow pits are properly implemented without adverse impacts. The physical aspects of the monitoring program would outline

procedures for proper filling of the pit, measuring the integrity of the

321
sediment cap on the deposited material, and determining whether any sediment

is escaping during disposal operations. These procedures would involve bathymetric surveys, grain size analyses, and the use of remote sensing apparatus.

The biological aspects of the monitoring program would focus on determining

whether contaminants from the borrow pit disposal site are bioaccumulating in

marine organisms. Benthic organisms will be sampled along a transect crossing

the borrow pit site and adjacent areas, as well as a control pit site. Organisms at these sampling stations will be tested to determine if there are differences in the uptake and bioaccumulation rates between the borrow pit site

and the control site. If there are statistically significant differences, a

determination would be made whether the differences are environmentally significant and whether the borrow pit disposal site is the cause of this

situation.

The management plan that is being developed for the operational program

will encompass a wide array of topics, from the sediment characterization

scheme, to the monitoring program, to a decision framework that will determine

what steps have to be followed to ensure that a borrow pit disposal site is

operated at an optimal level with minimal environmental impact.

CONCLUSION

From the evaluative criteria and the input of all of the interested governmental agencies, environmental and industrial interests, and others involved in the project, it appears that the best method for implementing an

operational program for disposal in borrow pits is to use an existing pit

while at the same time beginning construction of a new pit.

The draft SEIS will be released for public comment and review in January

1988.

REFERENCES

Benniger, L. K., Lewis, D. M., and Turekian, K. K. 1975. "The Use of Natural

Lead-210 as a Heavy Metal Tracer in the River-Estuary System," Marine Chemistry in the Coastal Environment, American Chemical Society Symposium Series

No. 18, pp 202-210.

Bokuniewicz, H. J. 1979. "Stability and Fate of Dredged Sediment," Proceedings, 11th Dredging Seminar/Western Dredging Conference, Baltimore, Md.

Bokuniewicz, H. J., Cerrato, R. M., and Hirschberg, D. 1986. "Studies in the

Lower Bay Associated with the Burial of Dredged Sediment in Subaqueous Borrow

Pits," Marine Sciences Research Center Special Report 74, State University of

New York, Stony Brook.

Bokuniewicz, H. J., Cerrato, R. M., and Mitchell, A. 1981. "Criteria for

Caps at Subaqueous Disposal Sites," Proceedings, Seminar on Dredging and Related Problems in the Mid-Atlantic Region, Ecological Analysts, Inc., Sparks,

Md., pp 272-278.

322
Brannon, J. M., Hoeppel, R. E., Smith, I., and Gunnison, D. 1985. "Long-Term

Effectiveness of Capping in Isolating Dutch Kills Sediment from Biota and the

Overlying Water," Miscellaneous Paper EL-85-37, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

• 1986. "Effectiveness of Capping in Isolating Dutch Kills Sediments from Biota and the Overlying Water," Miscellaneous Paper D-86-2, US Army

Engineer Waterways Experiment Station, Vicksburg, Miss.

Cerrato, R. M., Bokuniewicz, H. J., and Ellsworth, J. In press. "Siting Containment Islands in New York Harbor," Marine Sciences Research Center, State

University of New York, Stony Brook.

Cerrato, R. M., and Scheier, F. T. 1984. "The Effect of Borrow Pits on the

Distribution and Abundance of Benthic Fauna in the Lower Bay of New York Harbor," Marine Sciences Research Center Special Report No. 59, State University

of New York, Stony Brook.

Coch, C., Tavolaro, J., Krauser, R., and Tischbein, P. 1983. "Alternatives

to Open Water Disposal of Contaminated Dredged Material," Management of Bottom

Sediments Containing Toxic Substances, Proceedings of the 9th US/Japan Experts

Meeting, T. R. Patin, ed., US Army Corps of Engineers, Water Resources Support

Center, pp 176-197.

Connor, W. G., Aurand, D., Leslie, M., Slaughter, J., Amr, A., and

Ravenscroft, F. 1. 1979. "Dredged Material Disposal Within the New York District: Present Practices and Candidate Alternatives," MITRE Technical Report

MTR-7808, prepared for the US Army Engineer District, New York, New York.

Conover, D. R., Cerrato, R. M., and Bokuniewicz, H. J. 1985. "Effect of

Borrow Pits on the Abundance and Distribution of Fishes in the Lower Bay of

New York Harbor," Marine Sciences Research Center Special Report No. 64, State

University of New York, Stony Brook.

Environmental Protection Agency/Corps of Engineers Technical Committee on Criteria for Dredged and Fill Material. 1977. "Ecological Evaluation of Proposed Discharge of Dredged Material Into Ocean Waters; Implementation Manual

for Section 103 of Public Law 92-532 (Marine Protection, Research, and Sanctuaries Act of 1972)," Environmental Effects Laboratory, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Kastens, K. A., Fray, C. T., and Schubel, J. R. 1978 (Mar). "Environmental

Effects of Sand Mining in the Lower Bay of New York Harbor," Marine Sciences

Research Center Special Report No. 15, State University of New York, Stony

Brook.

Kinsman, B., Schubel, J. R., Carroll, G. E., and Glackin-Sundell, M. 1979.

"A Suggestion for Anticipating Alterations in Wave Action on Shores Consequent

Upon Changes in Water Depth in Harbors and Coastal Waters," Marine Sciences

Research Center Special Report No. 27, State University of New York, Stony

Brook.

323
Mansky, J. M. 1984. "Capping of Dredged Material Disposal Management for New

York Harbor," Management of Bottom Sediments Containing Toxic Substances, Proceedings of the 8th US/Japan Experts Meeting, T. R. Patin, ed., US Army Corps

of Engineers, Water Resources Support Center, pp 78-93.

McGrath, R. A. 1974. "Benthic Macrofaunal Census of Raritan Bay -

Preliminary Results," Proceedings, Third Hudson River Ecology Symposia.

National Marine Fisheries Service. 1984. "Seasonal Occurrence of Finfish and

Larger Invertebrates at Eight Locations in Lower and Sandy Hook Bays," Northeast Fisheries Center, Sandy Hook Laboratories, Highlands, N. J.

New York Bight Restoration Group. 1984. "An Alternative Strategy for Disposal of Dredged Materials from the Greater New York Harbor Region: A

Citizens Proposal," Report to the Steering Committee and Public Interest Coordination Group of the Dredged Material Disposal Management Plan for the Port

of New York and New Jersey.

Pacheco, A. L. 1983. "Seasonal Occurrence of Finfish and Larger Invertebrates at Three Sites in Lower New York Harbor," NMFS Northeast Fisheries Center, Sandy Hook Laboratories, Highlands, N. J.

Sumeri, A. 1984. "Capped In-Water Disposal of Contaminated Dredged Material," Dredging and Dredged Material Disposal, Vol 2, Proceedings, Conference

Dredging '84, R. L. Montgomery and J. W. Leach, eds., American Society of

Civil Engineers, pp 644-653.

Suszkowski, D. J., and Mansky, J. M. 1981. "The Disposal of Sediments

Dredged from New York Harbor," Management of Bottom Sediments Containing Toxic

Substances, Proceedings of the 6th US/Japan Experts Meeting, US Army Water

Resources Support Center.

Swartz, S. M., and Brinkhuis, B. H. 1978. "The Impact of Dredged Holes on

Oxygen Demand in the Lower Bay, New York Harbor," Marine Sciences Research

Center Special Report No. 17, State University of New York, Stony Brook.

Tavolaro, J. F., and Zammit, J. 1986. "Dredged Material Disposal Management

Studies for the Port of New York and New Jersey," Management of Bottom Sediments Containing Toxic Substances, Proceedings of the 12th US/Japan Experts

Meeting (in preparation), US Army Corps of Engineers.

Truitt, C. L. 1986. "The Duwamish Waterway Capping Demonstration Project:

Engineering Analysis and Results of Physical Monitoring," Technical Report

D-86-2, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

US Army Engineer District, New York. 1983 (Mar). "Disposal of Dredged Material from the Port of New York and New Jersey," Final Environmental Impact

Statement, New York, N. Y.

_ 1987 (Sep). "Use of Subaqueous Borrow Pits for the Disposal of

Dredged Material," Preliminary Draft Supplemental Environmental Impact Statement, New York, N. Y.

324
Wong, K., and Wilson, R. E. 1979. "An Assessment of the Effects of Bathymetric Changes Associated with Sand and Gravel Mining on Tidal Circulation in the

Lower Bay of New York Harbor," Marine Sciences Research Center Special Report

No. 18, State University of New York, Stony Brook.

Woodhead, P. M. J., and McCafferty, S. S. 1986. "Report on the Fish Community of Lower New York Harbor in Relation to Borrow Pit Sites," prepared by

Marine Sciences Research Center, State University of New York, Stony Brook,

for US Army Engineer District, New York, New York, N. Y.

325
DISPOSAL AND TREATMENT OF CONTAMINATED DREDGED MATERIAL

K. Fujii, T. Maekawa in Japan Dredging and Reclamation Engineering Association

2-8, Toranomon 1-chome, Minato-ku, Tokyo, Japan

ABSTRACT S___ 

__ This paper describes the dredging and upland dis- i ___ posal of about 30,000 m3 of polychlorinated biphenyl

(PCB)-contaminated (>10 ppm) dredged material for the

purpose of determining a treatment method that is safe

IQW and does not induce secondary contamination.

A cutterless pump dredge was used, and the

dredged material was transferred to the discharge

basin by pipeline. The dredging depth averaged 76 cm,

as compared with the planned depth of 70 cm. No increase in turbidity was observed during dredging.

The basin was subdivided, and the residual water

treatment was carried out by transferring the dredged

material alternatively to each basin, where dredging

and plain sedimentation were conducted. The seIregated water was sand filtered. About 400,000 m of

water was disposed, with turbidity under 10 degrees

(draining standard was below 30 degrees) throughout

the work.

The final disposal was made by draining the disposal area, surrounding it with embankment, and covering with impervious sheeting. The dredged material

was allowed to solidify, and the surface was covered

with sand and gravel and sealed with asphalt.

INTRODUCTION

The contamination that results from municipal and industrial wastes

deteriorates the quality of the water and the bottom sediment and has significant impact on marine life. These contaminants tend to accumulate on the

bottom, creating a source of pollution. Therefore, in developing a water

purification plan, it is necessary to remove this pollution source by dredging

or isolating it from the water area, in addition to controlling inflow to the

area.

This paper describes the development of a plan for the removal and

disposal of PCB-contaminated dredged material, with emphasis on safety and

minimizing secondary pollution. Also discussed are methods of treatment,

facilities, and actual results obtained in the residual water treatment tests.

326

92-16028 Di | |ll I HiI]!I IIN liI Ii
DISPOSAL AND TREATMENT PLAN

Background

Polychlorinated biphenyls have been widely used in insulating oils and

synthetic resin plastics because of their insulation and incombustibility.

They have also been added to ship paints in quantity for improved waterproofing and durability. However, the manufacture and sale of PCBs was forbidden in 1972 because their toxicity had been proven.

The work reported herein arose from PCB contamination that occurred

before the ban. In the dockyard, as ships were repaired, paint fragments were

washed or chipped off, and had been drained and piled in the foreground area.

In the disposal and treatment of the dredged materials, especially those

containing harmful materials, it is necessary to dispose of them using a safe,

secure, and efficient method, with considerable care about the environmental

effects--not inducing secondary pollution by stirring and diffusion, as well

as preventing escape from the disposal area.

This project involved dredging in the area shown in Figure I and upland

disposal, considering the following basic policies.

a. The subject material is removed by dredge and discharged at the

disposal area.

areae4

Figure 1. Project location

327
b. The dredged material is to be allowed to settle in the disposal area.

The segregated water is controlled under the disposition rule and

drained into the sea after the drain water standard is fulfilled.

c. In the final disposal, the dredged material, which will have been

reduced as much as possible, is to be sealed in the area.

Preliminary investigations and tests were conducted, the results of which

are referred to as the "Interim Policy Concerning Treatment and Disposition of

the Bottom Material." This involved examination of the disposal and treatment

engineering system, with the main object to prevent secondary pollution. This

procedure is shown in Figure 2.

Preliminary Tests and Method Selection

The preliminary tests that were conducted included examination of the

bottom material to confirm the range of the work and to select engineering

methods (Table 1).

Table 2 shows the selection criteria for work methods concerning dredging, transportation, discharge, residual water treatment, and final disposal,

based on the disposal and treatment plan for the project.

Operational Conditions

Dredging Area

The range of the contaminated bottom material (PCB content >10 ppm) was

determined to be: area (A) = 40,000 m2 , thickness (t) = 40 cm, and volume

(V) = 16,000 m3 .

In order to clear the work area of contaminated material, 5 m in area and

30 cm in depth were added to the contaminated range of area. Final dimensions

were: A = 43,550 m2 , t = 70 cm, and V = 30,500 m3 .

Dredged Material Characteristics

The average properties of the bottom material are shown in Table 3. The

PCB elution and all other contaminants were below acceptable standards.

Water Depth

The water depth in the dredging area was in the range of 9.9 to 20.7 m

from the existing ground level and tide level. On the quay side of the

removal area, a 25-m section makes a steep slope, the cross section of which

is represented in Figure 3.

Discharge Basin and Final Disposal Area

An area of about 60,000 m2 was designed for disposal, including the discharge basin and the residual water treatment facilities. The final disposal

area was created by reducing the area of the discharge basin.

328
Bottom material Bottom material Bottom material

analysis analysis analysis

harmful material IPCB IIhvsa al Pro ert

Disposal area Removal standard Soundin

structural standardI

Decision of disposal Decision of removal ecision of area structure extension/area, redging method

drededcolues, soil

Planned~ DeciSionpofifional cnito

disaraofa outincare bain

Execuionpoifina

Fuex2.mixationato rcdr fdso

Vo e cand e treatment plan in et rdgn

tes Pai sd29n
TABLE 1. OUTLINE OF PRELIMINARY TESTS

Residual

Water Final

Area Test Parameter Dredging Disposal Treatment Disposal Monitoring

Dredging Bottom material PCB (content) X X X X X

area examination

Harmful material

(elution)

Cr, Cd, CN, Pb, As, X X X X X

T-Hg, Org-P, PCB

Organic materials - X X X X X

Ignition loss,

sulfide

Physical property X X I X X

Grading, water content, weight of soil

constituents, liquid

limit, plastic limit

Water pH, COD, DO, PCB, SS, X X

examination turbidity, degree of

transparency

Sounding Water depth, existing X X

ground shape

Hydrologic Flow direction, flow X X

regime speed

examination

Disposal Topographical Ground height, X X

area survey topography

Geographic N-value, water con- X

examination tent, weight of soil

constituents, grading, unconfined compression strength

Residual Water corre- PCB, SS, turbidity, X

water lation test degree of

treatment transparency

Sedimentation Volume of material, X

test consolidation, tur-

(plained, bidity, and pH of

coagulated) segregated water

Sand filtering Amount, turbidity, SS X

test

Discharge Discharged Water content, grading X

basin material

property

examination

Discharge Dredged material X volume volume

examination

Solidification Unconfined compress'on X test strength

330
TABLE 2. SELECTION OF METHODS

Activity Feature To Be Examined Method Selected

Dredging Shallow dredging (little unnec- Exclusive pump dredge

esary dredging)

Accurate dredging of stipulated Cutterless submarine type

thickness along the existing

ground (No "left-over"

material)

No water pollution should occur

Adaptability for water depth

Compatibility with transportation and discharge methods

Transportation Accuracy Pipeline connection from

No leakage dredge to discharge

basin

Disposal Discharge basin of partition Embankment closing

type Impervious sheeting

Stability of surrounding

embankment

Adequate basin size

Ease of final disposal

Residual water Adherence to drainage Two-part partition of

treatment standard basin. Stationary sediStable treatment throughout work mentation by alternating

period discharges

Adaptability for the volume of Sand-filtering treatment

treatment of segregated water

Final Disposal area of partition type Embankment partly sheet

disposal Stability of disposal area pile

Sealing of disposal area Solidification of dredged

material

Impervious sheeting, overlaid with asphalt

Residual Water Quality Standards. Table 4 summarizes these standards.

DREDGING

Since the quay side made a steep slope of about 17 percent and was littered with obstacles such as wire, this part was worked first by grab dredge

and then by a mixed-air jet pump. The remaining area was dredged by an exclusive pump dredge (cutterless submarine type). Figure 4 shows the dredging

work areas.

331
TABLE 3. BOTTOM MATERIAL PROPERTIES

Parameter Average Value (Range)

Water content, % 156.1 (127.8-210.7)

Weight of soil 2.670 (2.649-2.688)

constituents

Grading

Gravel, % 0.1 (0-0.5)

Sand, % 1.8 (0-5.8)

Silt, % 44.3 (36.0-53.3)

Clay, % 53.8 (45.0-64.0)

Soil classification Clay

Liquid limit, % 109.3 (101.8-123.3)

Plastic limit, % 30.4 (27.4-35.2)

Organic material

Ignition loss, % 11.0 (1.3-16.4)

Sulfide, mg/g 1.53 (0.03-4.78)

Contaminant

Hg compound, mg/i <0.0005*

Cd compound, mg/i <0.02*

Pb compound, mg/i <0.2*

Cr compound, mg/i <0.05*

As compound, mg/i <0.02*

CN compound, mg/i <0.1*

Org-P compound, mg/i <0.0001*

PCB compound, mg/i <0.001*

* Below acceptable standard.

Total distance

0 5I n .. .. 15

-10.00m

Quay

- 15 Cmrn S•/ Exlstinq qteund

Figure 3. Existing ground shape of

dredging area

332
TABLE 4. STANDARDS FOR RESIDUAL WATER

Parameter Standard Value

PCB Below 0.003 mg/t

Suspended solids Below 30 mg/i

Turbidity Below 30 degrees

Hg and alkyl Hg and other Below 0.005 mg/i

Hg compound

Alkyl Hg compound None detected

Cd and its compound Below 0.1 mg/i

CN compound Below 1.0 mg/1

Org-P compound Below 1.0 mg/k

Pb compound Below 1.0 mg/i

Cr compound Below 0.5 mg/i

As and its compound Below 0.5 mg/i

Dredging __ area

90m 210M 80M

Pump dredging

A = 38,300m2

V = 26,810 m3

Grab & mixed-air

Extra jet pump dredging

dredging area A - 5,250 m2

S 'V = 365m 3

Pump dredging area

Sm

Pollution

prevention

membrane

quay

Grbanti mixed-air jet pump

dredging area

Figure 4. Dredging area by work type

333
Pump Dredging

Figure 5 shows the process used for transfer and discharge of dredged

material by pump dredging.

Exclusive Shore pipe

pump dredger

7N A==Discharge

Dredgin g Transportation,

Cutterless discharge

submarine pump dredge Pipe

D2400PS 650m/m L - 1340m

Figure 5. Pump dredging work flow

The dredge used is described in Table 5 and shown in Figure 6 and

Photos I and 2.

Grab Dredging

In grab dredging, a closed-type grab was used to prevent generation and

diffusion of turbidity. A pollution-prevention membrane (340 m long, 10 m

deep) was stretched around the work area. This process is illustrated in

Figure 7.

TABLE 5. SPECIFICATIONS OF PUMP DREDGE DAINI-TAIAN MARU

Feature Description

Hull, total length 81.50 m

Length between verticals 47.40 m

Width 14.50 m

Depth 3.50 m

Draft 2.25 m

Dredging depth 25.00 m

Ladder pump, 2,300 m3 /hr x 23 m x 500 rpm, 1 unit

driving motor (underwater variable-speed

type), 300 kW

Onboard pump, 3,000 m3 /hr x 68 m x 356 rpm, I unit

diesel driving engine, 2,400 ps

Ladder winch, electric, single-barrel type I unit

(20 t x 18 m/min x 100 kW)

Swing winch, electric, double-barrel type I unit

(11 t x 0-16 m/min x 75 kW)

Spud winch, electric, double-barrel type I unit

(16 t x 18 m/mmn x 75 kW)

334
Loai* eqginutipmeentmte

Locattn eeasuiepmenen

speeds Dtigging wte

Main generator change ing winch

Prime oer for onboard pump Engine roominh o

Figure 6. Pump dredge

-P

Photo 1. Pump dredge Photo 2. Bow of pump dredge

335
, Clamshell Grab dredge

Pollution • dm rc

prevention

membrane a

IGrab dredge Barge Clamshelll Closed dump [Closed type 2 m 3 .500 m 3 2 m 3 I truck 11 t

Figure 7. Grab dredging

Mixed-Air Jet Pump Dredging

After grab dredging, the mixed-air jet pump dredge (Figure 8) was used.

Closed

Wihnte6 -n- disposa area Quay

prevwenins

emembrane

v SMixed-a Dredsincouri ir Jeit ...... .......Loadi rr angemet of Ithradsposjalo dscharge rai

S pump 250 ps 1ag 31:111and pump] Closed dump iPontoon 200 t ' 500DIJ ir-inch I t ck t l

Figure 8. Mixed-air jet pump dredging

CONSTRUCTION OF DISCHRGE BASIN

Within the 60,000-m 2 disposal area, a discharge basin and residual water

treatment facilities were installed. The discharge basin was erected with

embankment by spot excavation. Inside, an impervious sheet was spread to prevent water seepage and scouring. The arrangement of the disposal area is

shown in Figure 9 and Photo 3.

336
u

r_ r

00

0 w0

3- 0 v 0w

00C 1 0 01C

.0 -H

0 0

6 SI #o is $ 0 

Dicarg ai )icar ai

.4 .4 4 ,-.

4337
* 4" --- .-

I I

Photo 3. View of disposal area

RESIDUAL WATER TREATMENT

The residual water was treated by two-part separation of the discharge

basin, alternating discharge and sedimentation. The segregated water was

sand-filtered. This treatment is illustrated in Figure 10.

SpillwayS' Drain pipe

M i x t u r e ------.. . . • - - -

__-_ n• _Jl I NI • I q. tJ--__• Effluence

Seetleable onfailyion sotlds 

sedimentation)

Figure 10. Residual water treatment

DISPOSAL

The accumulated material in the discharge basin was enclosed in an area

about half the size of the basin. The final disposal area is shown in

Figure 11.

The structure of the final disposal area Includes embankment, as for the

discharge basin, partially closed in by sheet piling and covered with impervious sheeting. The dredged material was allowed to solidify, and was transferred to the final disposal area and covered with sand (10 cm thick), gravel

(15 cm thick), and asphalt. Figure 12 illustrates the final disposal process,

and Figure 13 presents a cross-sectional view of the disposal area.

338
le I /G .

.' !.... .......... .. I n*i......... . .. .I .I..

I•:~~~~= ..... --Z 2- ,,,,

*• 1 S***IIuI[ 'iiiI I

"!'.. S:l I IIIII~ .I I l disposal II . -' . •~ ~ ~ ~ ~ I31 r I.' IIII.• I-,ff. I II IS II ~Steel• "'I°I

Figure - - 11. Fina disposal l arI

~iIIi ___iiiiii_________

*I OS, -a....... ,lr**" ,, ,,ig "

D hI basin . . . * . . " HO sump DIic

Figure basiFinal barea dsposal 

retrenched baand • hllw

bai Discharge -- ,DischargebaiQ 

Bai nc a g ba i _• m retre chmen

re t relchment

SLo final

I[~ ~ ~ ~~~~~~d s'ase pos Itcag area•Isliiie aeia Discharge basin 1 r

solidifiedsa matrea

I S r 

Overlay

Figure 12. Final disposal process

MONITORING

ensure Monitoring that no secondary of the dredging polluthon and was disposal activities was conducted to occurring. A diagram of the monitoring stations and a summary of the monitoring plan are presented in Figure 14 and

Table 6, respectively.

339
86.0

+8.3 89 Ovra Asphalt paved

+6.6 Solidified material Crushed

+6-8stone

_TA :Sand

material

Impervious

sheet

Figure 13. Cross-sectional view of final disposal area

I .uod~t IBMio

Figure 14. M onitorigsain

Dredgini Eien

Shallow

A dredgig is sumary pesentd ofisthare as opeatina Tblee7 codtosadefinyofhepp

AcacBorderlce oTf rrk

""are a . sea

S40

AL• ubolrdlnete station

Figure 14. Monitoring stations

TEST RESULTS

Dredging Efficiency

A summary of the operational conditions and efficiency of the pump

dredging is presented as Table 7.

Accuracy of Dredging

Representative dredging cross sections are shown in Figure 15. The

average dredging depth was 76 cm, in the level area and 97 cm In the sloping

area.

340
9: 4)c

a 09

04Q)

-4 4) U I

r-L 4) 0 6

O 10

10 1

z 0) U~4 00=4G

04 04 04 eO -O 0, . .4 "4 

44)

Z.*0 = U 4 

0 .0 

Vt. f

0

41 0 41 10 V)

4)

0 ft4 ~ ~ 4 4 4

04 - 0 CcI U- -

ccc c - u40- 4o a to 41)4 001 31- 4.

- I-L

04 I V -C4 . I- 

.04S.. .

341,
TABLE 7. PUMP DREDGING EFFICIENCY*

Operational Feature Value

Work days 26

In-situ sediment volume 33,370 m3

Dredged material (sediment + water) 417,020 m3

Operation hours 195

Dredging rate (in-situ) 171 m3 /hr

Dredging rate (sediment + water) 2,131 m3 /hr

Solids concentration (percent) 8.0

* Dredging width, 40-60 m; swing speed, 4-6 m/min; dredging depth, 40 cm (first dredging), 30 cm (repeat).

------- lann

- l&• ~- i? oe

areI1 -l. ' * " ' . . S-I• .. 1

Slope area - Level areaSlope area -- Level ae

9-,250-n. .mm--5-,

Figure 15. Cross-sectional view of pump dredging

Use of the exclusive (cutterless) pump dredge requires greater depth

accuracy than the cutter pump because the dredging would be ineffective if all

contaminated material were not dredged, and excess dredging would create management and disposal problems. The dredge was equipped with a depth control

device that recorded the dredging depth continuously. As a result, accuracy

was obtained, with little additional dredging required to achieve the planned

depth of 70 cm (6 cm for the level area, 27 cm for the sloping area).

Turbidity

Figure 16 shows the results of water quality monitoring at the principal

stations during dredging. Throughout the work period, turbidity was <5 degrees (standard value: <25 degrees), confirming that dredging created no

problems of generation and diffusion of turbidity.

Volumetric Change

Dredged material increases in apparent volume by being mixed with water,

and after dredging, does not compress and dehydrate until a mound forms in the

discharge basin. Changes of volume must be considered in planning the

342
Standard value. %25 degrees

4

, .3-

2830 1 3 57 Iti72l357I 57913 135 1719 212325>91

Jaur erayMarch April

Grab dredging Mixed-air jet Pump dredging pump dredging

Standard value. 4 $sg/I

3

28 30 1 3 5 7 9 11 13 1517 19 212325 27 1 5 791113 151'71A9123 A21272931 24

January Pebruarv March IAprilI

Grab dredging Mixed-air jet Pump dredging pump dredging

Standard value. 7 < n t 9

9.0-------------------------------------------------------------

8.0 9.

7.0 ýStandard value

28 30 1 3 5 7 9 1113 15 1719 2123 25 2) 1 3 5 7 9 113' 5 17 19 2123 27 31 A2 4L Jour Verur March April

Grab dredging Mixed-air jet Pump dredging

pump dredging

Standard value. '2mgI

11

K10

9 Standard value

t80 35L 7' 911'131517191235?1 A A2'3 '5L 7 9 A1'3 Is17 1'92123 25 Z7 32 44

January February March April

Grab dredging Mixed-air jet Pump dredging

Figure 16. Results of water quality monitoring

343
discharge volume. The modulus of volume change was 1.41, comparing the total

dredged volume of 37,500 m3 with the discharge basin volume of 52,900 m3

4 days after completion of dredging.

Residual Water Quality

Figure 17 shows the turbidity of the treated water after sand-filtering.

The treated water volume through the work period amounted to 388,100 m3 , the

turbidity of which remained less than 10 degrees. This clearly met the

standard value of 30 degrees.

Standard value, <30 degrees

Figure 17. Residual water quality 6

after treatment '.4

=2

18 20 22 24 26 28 3031 1 3 5

March April

INVESTIGATION OF RESIDUAL WATER TREATMENT METHODS

Since pollution by PCBs was a major concern, meticulous treatment of

residual water was emphasized during the planning stage of the project. Various tests were conducted at each step of the treatment processes to identify

the basic design elements for developing the best possible treatment method.

Generally, the focus of residual water treatment is on suspended solids

(SS). Processes applied include solid-liquid segregation such as plain sedimentation, coagulated sedimentation, and filtering.

In consideration of the work objectives and the residual water quality

standards, the treatment methods were applied separately or in combination.

Figure 18 shows these methods.

Water Quality Standards

Standards provided in the Prime Minister's Office Ordinance stipulate

that the "water quality standards of the seawater draining from the residual

water outlet" have a PCB concentration below 0.003 mg/i. Standards for this

project include SS and turbidity as visual indices, in addition to PCB. Since

heavy metals generally adhere to soil grains, SS in water and heavy metal

concentration are said to have correlation. Therefore, correlation tests for

PCB, SS, and turbidity were conducted, as shown in Figures 19 and 20.

Correlation among items is clearly indicated and, in the case of PCB and

SS, the cohesion rate was about 1/36 against the theoretical line (in which

all PCB is adhered to soil grains). The PCB content of the sample grain was

344
No aggLutinate added

Mixture M Agluicharte baein - 100-200 PP_ effluence

Agglutinate No added < 00-200 P

---- f ischar e basin SMixture effluence

No agglutinate added No agglutinate added

@ Mixture -f Dischargebasi -. - Sedimentation basin " effluence

No •) agglutinate lx~re---• added '•-------Sedmenatin schr~ebas'n Agglutinate added bsin } 50-100 1pH• affluence

Agglutinate added Aglutinate added •5-0 I

® Mixture---fischer e basin -- --- ed --- o b ,,effluence

No agglutinate added U& Iutinate added < 20 PPM

tlixture -- Dischar e basein fn " F-----nb iter bd effluence

Agglutinate added Anglutinste added < 20 PPM 2) Mixture - Dechar e besin Sedimentati.. basin Filter bed effluence

Figure 18. Residual water treatment methods

Drain water standarA value 3 ppb

- ,, Theoretical line too /" / f (PCB 25.9 mg/kg dry)

to' is s" Theoretical (PCB 100 1•k. line drvl ba

0. s / (l'C lO drISSI 0 .97?x(Tbl-3.73

I0. -• Ol.S~lll

I0 - -

I0 I0'I'I'0 • • • • I • I

SS, I0/ Tubidtydegee

of ,0 mgk

Z C20-4D 0.. 

ND 0.02 PPbTog th0 S0 0 20 no 4s0 p in a0 h

SS, Mg/E Turbidity, degrees

Figure 19. Correlation between Figure 20. Correlation between

PCB and SS SS and turbidity

25.9 mg/kg, and the SS corresponding to the standard value 0.003 mg/i was calculated to be 30 mg/i from the theoretical line of the maximum concentration

of 100 mg/kg.

Though the SS standard concerning dredging is not provided in law, the

Water Pollution Prevention Act and related local government regulations concerning specific factory facilities stipulate less than 30 mg/i as the daily

average and 35 mg/i as the maximum. It was determined for this project that

!30 mg/i SS will achieve the PCB standard value.

345
Since analyses of PCB and SS take time and monitoring during dredging was

difficult, turbidity (30 degrees) was selected as the control value, since it

can be readily determined.

Table 4 lists the residual water quality standards that were based on the

considerations described above and legal requirements.

Treatment Tests

Plain Sedimentation Test

The turbidity change of the segregated water by plain sedimentation

(sediment content, 5 to 30 percent) is shown in Figure 21.

1.0W -... Concentration 5% -- Concentration 10%

S. --- Concentration 15%

'.. -Concentration 20%

V -•_W - Concentration 30%

Settling time, minues

Figure 21. Turbidity of segregated water

by plain sedimentation

Coagulated Sedimentation Test

Two methods of coagulation, one to add coagulant to dredged material

directly (direct method) and the other to add segregated water in the discharge basin (shower method), were considered. Figure 22 shows the turbidity

change by the direct method; Figure 23 shows the treated water turbidity after

30 min by the shower method and the required amount of coagulant to lower the

turbidity below 30 degrees.

Concentration 52 Concentration 102

Na ade Concentration 15%

a No aglutinate added No amlutinate .added

Spa4 2pa added

10 \. 10 W H, 10 1 

Settling tiM, Sinutea Settling tLIM *in.tes Settling tiM, minutes

Figure 22. Turbidity of segregated water by coagulated

sedimentation (direct method)

346
Turbidity of

treated water

a'--- Polyset used

--. -&PAC used PAC needed

..... both PC and ght

polyner used

"PAC needed need

Turbidity of created water SS of raw water Agglutinate needed for wter SS of raw "ter

after 30 sIn a/I with 30 degrees of turbidity W&t

Figure 23. Coagulated sedimentation (shower method)

Volumetric Change Test

The modulus of volume change, which is indispensable in calculating the

discharge basin volume, is shown in Figure 24 with regard to plain and coagulated sedimentation of dredged material with water content 5 to 15 percent.

Sand Filtering Test

Using the filter device shown in Figure 25 and two kinds of sand, the

rate of filtration versus sand thickness and filter head and also the filtered water density versus the raw water were computed. The results are shown

in Table 8 and Figure 26.

Selection of Treatment Method

Based on a comparison of the test results and treatment methods, the

following conclusions may be drawn:

a. As to the natural stream sedimentation in the discharge basin, the

concentration estimated from the water area load was 110 to 600 mg/i

and the coagulated stream sedimentation was 25 to 600 mg/i. This is

because the precipitation function in the discharge basin deteriorates as the work progresses. It is difficult to maintain the treatment standard throughout the work period. (Treatment methods I

and 2, see Figure 18.)

347
No agglutinate added Concentration 5%

Concentration 5%

= • Concentration 101 r. W

S No a glutinate added F 15- 

oal

••'• 5 Conentraion 1Z - 15

Concentration 20 • ] --- .. , Concentat-ion-30% 0 -4|0

10~~~ Co0 5 -4-p 2 mde

jadded

0 1 30 0 I0' (r0' I I0 L0 -1' 1O'

Settling time, minutes Settling time, minutes

Concentration 10% a Concentration 15%

SU 3 ppm added 4

10 10 ..... No a 4 PM added

.4 a No lutinate added /

5 5 PP 'PM_

- 0 ad aeddedd

0 1 10 & 10 0' 1

Settling time, minutes Settling time, minutes

Figure 24. Volumetric change modulus of dredged material

Raw water

Residual

water

Crushed

stone 10-201"

Vinyl

chloride pipe 6, IODm)

Figure 25. Sand-filter test

equipment

Crushed stone -

348
720

IS

0 e

I1 n t 100- 4O Sao.

$41

O170 0 110 

and filter head

f. ~ ouec ~ 60 aneofdded Sh thickessa 130 7 asi.5 to1.O h

lated sdi (Fittered ahwn (heiteede d sfandtiat Boices

ased0 tettreutadteop San athicknaecs dtonssttonr

(ti l terd sandsBandh

sereaed0ae weecoe stem san thoickngess-qes

130L

ia 20 30

Rate of filtration, r/hr

Figure 26. Rate of filtration by sand thickness

and filter head

f. The volume change of dredged material in 7 days is 1.5 to 1.8 in the

case of natural sedimentation and 1.9 to 2.1 in the case of coagulated sedimentation, showing the tendency of aggutinate to increase

volume.

Based on the test results and the operational conditions, stationary

sedimentation treate ylt in the discharge basin and sand-filtering of the

segregated water wer..' chosen as the most promising techniques.

Treatment Facilities

When stationary sedimentation treatment is done in a single operation

daily, the time for sand-filtering and draining of the segregated water is

inadequate to attain the desired result, and the scale of the facilities as

well as the water volume must be very large. Therefore, the discharge basin

was subdivided, and discharge and sedimentation were alternated. Figure 27

shows the treatment cycle, and Table 9 outlines the use and scale of the

treatment facilities.

The sand-filter basin (Photo 4) was designed with a filter head of

190 cm, a sand thickness of 130 cm from the planned water volume of

1,650 m3 /hr, and a filtering speed (as an example) of 3.0 m/hr. Thus, the

349

L
TABLE 8. TREATMENT RESULTS

Turbidity of Raw Turbidity of Treated Elimination

Water, degrees Water, degrees Rate, Z

Filter Head 150 cm, Sand Thickness

90 cm, Sand A

75 2 97

100 2 98

Filter Head 150 cm, Sand Thickness

130 cm, Sand A

50 2 95

103 2 98

160 3 98

220 2 99

265 2 99

315 2 99

b. In the case in which the segregated water is treated in the natural

sedimentation pond after the stream sedimentation in the discharge

basin, its SS structure of small grains is very slow to precipitate;

therefore, it is difficult to fulfill the standards. (Treatment

method 3.)

c. Likewise, in the case of coagulated sedimentation, it is assumed that

the amount of agglutinate can be managed to attain the desired result, but •he basin should be 40 to 45 m wide and 120 to 130 m long

to fulfill the facilities design standard (basin stream velocity

<40 cm/min and settling time 3 to 5 hr). Therefore, it is difficult

to'obtain the land to construct such facilities. (Treatment

methods 4 and 5.)

d. By the sand-filter treatment, the density of treated water (2 to

3 mg/t) can be obtained from the raw water (50 to 300 mg/t), which is

highly efficient and stable. (Treatment methods 6 and 7.)

e. The natural stationary sedimentation in the discharge basin can proJuce 30 to 65 mg/1 of segregated water in 3 hr, and the coagulated

stationary sedimentation, 20 to 55 mg/1.

350
1st day 2nd day

Hours 2 24 1 1? 1! 3618 22, 0 2 4 61If 12 14 16 1• 20 22

DisDhar e IýMw

Discharge Stationary sedimentation -h 7

basin _____

Treatment

Preparation 1hr •"_

Discharge 16hr

Discharge Stationary sedimentation .hr

basin .h i Treatment 9.hr

Preparation _1_

Figure 27. Residual water treatment cycle

TABLE 9. RESIDUAL WATER TREATMENT FACILITIES

Facility Purpose Features Scale

Discharge Storage and precipi- Volume change rate: 200 m x 86 m x 3.3 m

basin tation of dredged 1.73 45,000 m3

material Storage volume: (2 basins)

20,800 m3

Marginal height:

0.5 m

Spillway Draining of segregated Rainfall increase 4.4-m width

water to sump est. 1.2 hr (2 units)

(1,350 m3 /hr)

Shallow Storage of water from Storage volume: 78 m x 25 m x 3.3 m

sump spillway for 2.1 hr 2,870 m3

(1,350 m3 /hr) (I pond)

Sand-filter Filtering of residual Volume, safety 15 m x 20 m

basin water rate: 1.2 (3 ponds)

(1,650 m3 )

Monitoring Observe filtered water Storage volume: 45 m x 17.6 m

pit quality for 0.6 hr x 2.5 m

1,000 m3

(1 pond)

Drainway Drainage to sea of (1,650 m3 ) * 650 m/m

filtered water that L = 380 m

meets the standard (2 routes)

351
Photo 4. Sand-filter basin

required filter area was calculated and designed to be 550 m, with three ponds

each with the area of 15 by 20 m. Two ponds were put into operation, and the

third was set aside for sand exchange.

The cross section of the sand-filter basin is shown in Figure 28, and the

arrangement of the infiltration gallery is shown in Figure 29. The monitoring

pit is shown in Photo 5.

Hnnitoring pit 414 Sand-filter basin

lo 3• " 49 0 " t don low

Rence slsotesnfletete are pot in| Fig 3

infiltrationOn

watr urbdiy anged bewe 0ad10dges hCruh tned ato. be higher

Crushed stone 2O-4Om/m

ý..ushed stone 40-500/m

She ple 1100

Figure 28. Cross section of sand-filter basin

Treatment Results

Results of the sand-filter treatment are plotted in Figure 30. The raw

water turbidity ranged between 10 and 100 degrees, which tended to be higher

in the latter part of the work period. However, the treated water turbidity

was kept stable at <10 degrees throughout the period, a highly satisfactory

result. The total volume of treated water was 388,100 m 3 .

CONCLUSIONS

In disposal of dredged material, especially that containing harmful materials, prevention of secondary pollution that may accompany the work is of

utmost importance. This paper reported a project that involved dredging and

352
Kana drain

2.&P

Cutoff concrete

1 T5 .. Shutter valve

Orn 5.2" 3m?7m AIMt 5 2M .41mfl23251 S2h ?.525M -Sam

IS O5m__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

aS a s

Figure 29. Arrangement of infiltration gallery of the sandfilter basin

Photo 5. Monitoring pit

353
TrI Trted uantityA

0 70.

Turbidity of V the raw water % 12.00

4D-

-64

20- Turbidity of4J0

the treated water

10 -.. b - ~ 4 LOW 20

12 13 14 15 16 17 18 19 20 1 2 223-7214 25 26 27 A9 2 30 3 1 1 12 31 4'1

March April

Figure 30. Results of sand-filter treatment

upland disposal of PCB-contaminated material. In this project, preliminary

investigations were conducted to select safe and effective work methods. The

work progressed safely as planned. No serious problems occurred, and the

objectives were met. The landfill area is now used as a parking lot.

Care and countermeasures to prevent adverse environmental effects are

always required in conducting water projects, regardless of the sediment quality. Therefore, the fundamental problems reported herein can be applied to

other dredging work. However, since the landfill disposal has inherent problems, such as volume change of dredged soil and estimation of residual water

concentration, continuous studies may be required.

354
LAKE RESTORATION BY DREDGING

R. F. Gorini

Port of Vancouver, PO Box 1180

Ir0 Vancouver, Washington 98666-1180

ABSTRACT t(0 This paper is a summary overview of the $17 million Vancouver Lake Restoration Project, the largest

project of its type ever undertaken through the Fed- gO... eral Clean Lakes Program. It was funded jointly by

the US Environmental Protection Agercy, the Washington

State Department of Ecology, and the Port of Vancouver. Although the project was conceived in 1965, a

nationwide program to help fund such projects did not

exist until 1976. Then, final approval was not

received until 1981, after many volumes of studies and

reviews. Construction was completed in June 1983,

after 30 months--6 months ahead of schedule and

underbudget.

A great deal of time, money, and energy was expended to demonstrate to Federal and state environmental agencies that dredging was a key tool in effecting

this lake's restoration. Their collective resistance

to this notion has been challenged by the project's

success. This paper focuses primarily on the dredging

aspects of the project. It identifies the concerns

raised, the dredging and materials handling methods

used, and the relative success of the techniques, not

only in terms of operational effectiveness but in

terms of environmental protection.

BACKGROUND

Vancouver Lake is a 2,600-acre (6,425-ha) lake lying in the floodplain of

the lower Columbia River in the southwestern corner of Washington State on the

west side of the City of Vancouver and north--across the Columbia River--from

the City of Portland, Oreg. It is within a 45-min drive of the million-plus

residents of the Portland-Vancouver metropolitan area and, in its restored

condition, has become an immensely popular recreational resource for our regional community.

Until the early years of this century, Vancouver Lake was a relatively

clear, moderately deep (6 to 8 m) lake cleansed twice yearly by the spring and

fall freshets of the Columbia River. Over the years, construction of dams on

the Columbia and dikes on the lowlands surrounding the lake virtually eliminated this natural flushing system.

5 92-16029 II IIIII II liIIII 111I
At the same time, urbanization in the 27-square mile (70-km2 ) drainage

basin feeding the lake's only tributary contributed substantial siltation and

pollution. At the start of project construction in early 1981, the lake's

depth averaged 1 m (at low water). It was not safe for human use and was in a

highly advanced state of eutrophication.

APPROACH

The $17 million Vancouver Lake Restoration Project is the largest project

of its type ever undertaken ir the United States under the National Clean

Lakes Program. By the phrase, "of its type," I refer specifically to a project having three key elements:

a. Limiting the inflow of pollutants from both urban and agricultural

nonpoint sources.

b. Flushing the lake with relatively clean Columbia River water.

c. Deepening and contouring the bottom of the lake.

Limiting the inflow of pollutants involved three actions, all of which are

being phased in over several years:

a. Elimination of septic tanks in the basin by a major expansion in the

city's sewer system.

b. Institution of a storm drainage and runoff control management plan in

the tributary drainage basin.

c. Establishment of an agricultural practices management program to control erosion, manage the application of fertilizers, and contain animal wastes to prevent entry to the waterway.

Flushing the lake with relatively clean Columbia River water was the key,

however. In constructing the 4,300-ft (1,310-m) flushing channel from the

Columbia River, we were merely imitating the natural system, based on the fact

that water flows downhill.

Specifically, the water flows on an 18-in. (46-cm) gradient over the

length of the channel and enters two 7-ft (2-m) culverts fitted with flap

gates that lead into the lake. Whenever the river water elevation is higher

than the lake water elevation, the riverflow opens the gates and flushes the

lake; at equilibrium or lower, the lake waters close the gates and backflow is

prevented.

Before construction, it was estimated that the waters of the lake turned

over every 25 to 28 years; with the flushing system in place, the waters of

the lake are renewed every 21 days or so. The improvement in water quality

has been significant.

The benefits of this system are twofold. First, and most obvious, is the

cleansing action itself. Secondly, the infusion of this "new" water inhibits

algae blooms. In short, the lake becomes a better habitat for fish and safer

for human contact.

356
As complex as this hydrological problem was, the key was dredging the

lake and handling the dredged material--about 9 million cubic yards (almost

6.9 million cubic meters). The intent and purpose of the dredging was threefold. The first and most important objective was to aid the flushing action.

The point was not simply to deepen the lake, but to contour and sculpt the

bottom of the lake to maximize the benefits of the flushing action.

Second, deepening selected portions or segments provided sump areas for

heavy sediments to settle. Three were built--one where the river enters the

flushing channel, one where the flushing channel enters the lake, and one

where the lake enters its only outlet, appropriately called "Lake River."

These "holes" also provide for ease of any future maintenance dredging, for

that is where the sediments collect.

Third, dredging and periodic overdredging provided environmental and

recreational benefits. This deepening allowed more year-round boating and

fishing and closer-to-shore swimming areas. The holes provided deeper and

cooler water for the fish species in the lake, and the deepening somewhat reduced turbidity caused by wind and wave action stirring the bottom sediments.

Several concerns had to be addressed:

a. What kinds of materials would be dredged.

b. How much material should be dredged.

c. Where in the lake would dredging occur.

d. Were any of the materials contaminated.

e. How would contaminated sediments be handled and disposed.

f. How would the uncontaminated sediments be handled and disposed.

.. What types of equipment would be used for dredging.

h. How would dredging occur, that is, where and when.

i. What would the total environmental impacts be and how would they be

minimized.

As it turned out, the bulk of the sediments dredged were fine silts, some

with clay, others more sandy in nature. There were also pockets of sands,

sands and gravel, and clays. Dredge production throughout was greater than

predicted.

Determination of the amount of material was the result of a carefully designed hydrological plan to maximize the benefits of flushing, including channel width, depth, distance from shore, and specific locations for overdredging

and for disposal of certain materials. The "operations plan," as it was

called, was executed with very few problems.

After much study it was discovered that some areas of the lake had contaminated sediments, specifically, with heavy metals and certain pesticides.

357
However, the studies and bioassays also demonstrated that these contaminants

were bound up in the soil particles and not available to the biota. This also

proved true with land disposal. No leaching of contaminants into the ground

water occurred. In short, no unique dredging or disposal methods were necessary to handle these sediments.

As one might imagine, identifying disposal sites for such a large volume

of material proved difficult. During the project, we constructed one island,

modified the shoreline on the east side of the lake, and filled about

600 acres of uplands (about 243 ha) in five locations (Figure 1).

Because of the nature and quantity of the material, the upland disposal

sites were constructed with large cells to provide sufficient time for decanting the dredged material before the return water went back to the lake. In

fact, the lake became the last "settling pond" in the chain; however, no water

quality standard violations occurred during the entire project.

Inttially, we had intended to build two islands, using silt curtains.

However, these did not perform as predicted. They did not contain the fine

sediments, and the outer rim of the one island that was built finally had to

be constructed using a clamshell dredge. In place of the second island, we

filled a portion of the east shore. Silt curtains proved only marginally successful in containing that site.

The Port went through a lengthy evaluation of dredging methods and

equipment, including the "Pneuma" system used in Japan and Europe, a system

that, in spite of its lower production and higher operating costs, might have

been required had our studies not shown that the contaminated sediments posed

no danger.

The contractor used a 24-in. (64-cm) cutter suction dredge (after dry

land excavation to the water table) to construct the flushing channel from the

Columbia River. As indicated above, a clamshell was used in constructing the

outer edge of the island.

The real ingenuity of the contractor was demonstrated in the lake dredging. Because of the shallow water, the boom on a 30-in. (76-cm) cutter suction dredge was shortened. However, to maximize production, the hull length

was doubled by welding another dredge hull with it. The ,arc of the dredge

swath was huge. Finally, to minimize costs, the dredge was electrified. An

18,000-ft (5,500-m) electrical cable supplied power. Further, transponders

were set up at key locations around the lake. The dredge captain always knew

exactly where he was operating relative to the dredging plan.

SUMMARY

The lake project not only resulted in improved water quality and aquatic

habitat but provided additional wetlands (east shore), additional waterfowl

habitat (the island), and better and higher agricultural land (the sediments

are quite fertile). The project actually increased the shoreline length in

the lake. Usage of the park on the lake's west shore went from a few hundred

visitors per day during the summer months to several thousand.

358
F ig ire I. Vincouver Lake, 1%'nshington, restoration project nrea

359
The Vancouver Lake Restoration Project has, thus far, been a success.

The water quality improvements exceeded prediction, and after nearly 5 years,

it appears that dredging maintenance will be much less than had been

predicted--once every 5 to 7 years in the flushing channel sediment sump

(estimated at 40,000 to 45,000 yd3 (about 3,060 to 3,440 m3 ) and perhaps once

every 40 to 50 years in the lake itself. Moreover, the environmental and recreational benefits are substantial.

That success would not have occurred without two key ingredients. First,

the documentation developed by the US Army Engineer Waterways Experiment Station's Dredged Material Research Program was vital in demonstrating that the

dredged materials would behave as predicted. Second, the dredging industry

and our contractor, Reidel International, in particular, demonstrated an ingenuity and knowledge that not only overcame problems and reduced costs, but

proved irrefutably that dredging is a tool not only for waterways development

but for environmental restoration and enhancement as well.

In conclusion, projects such as this one affirm that man can lay a kind

hand on the environment. Conferences such as this allow us to share these experiences and our growing knowledge and practical expertise. One wishes such

understanding could be spread to a broader audience.

360
AD-PO06 847-

THE LONDON DUMPING CONVENTION (LDC): REGULATION OF DREDGED

MATERIAL THROUGH GUIDELINES FOR APPLICATION OF THE

ANNEXES TO DREDGED MATERIAL

R. M. Engler

Environmental Laboratory

US Army Engineer Waterways Experiment Station

Vicksburg, Mississippi 39181-0631

ABSTRACT

The prevention of pollution of coastal/marine

waters is a major concern of the 61 nations signatory

to the LDC. The goal of the LDC by the member countries is to take all practical steps to prevent any

pollution of the sea and marine life, damage to amenities, or interference with other legitimate uses of

the sea (Article I of the LDC). All waste materials

dumped into the sea or proposed for sea dumping, including dredged material, are regulated on a global

basis by member nations through the LDC. The LDC construction is quite simple and straightforward. The

Articles comprise the legal framework, while the Annexes (i.e., I - Prohibited Materials, II - Materials

Requiring Special Care, and III - Provisions for Developing Regulatory Criteria) are the technical framework for implementation of the Articles. Technical

Guidelines for interpreting the Annexes comprise the

day-to-day working-level application of the LDC. The

LDC was formed in 1972 and did not distinguish among

waste materials. All were handled in precisely the

same manner, even though there were no technical reasons to do so. Through the application of the LDC,

guidelines were developed that began to separate

dredged material from other materials (e.g., sewage,

industrial waste). Recently (October 1986), after

several years of technical negotiation at the annual

LDC Consultative and Scientific Group meetings, special guidelines for dredged material were developed.

This paper will discuss the evolution of the "Guidelines for the Application of the Annexes to the Disposal of Dredged Material," their implementation, and

their meaning to the dredging and port interests.

INTRODUCTION

The Convention on the Prevention of Marine Pollution by Dumping of Waste

and Other Matter--known as the London Dumping Convention or LDC--was negotiated in November 1972. After ratification by 15 member nations, the LDC

3192-16030

Hl 11111l IlH II ~IllI
came into force in the United States on August 30, 1975. The contracting rstions have met annually since September 1976. There are now 61 nations signatory to the LDC.

The policy, regulatory, and technical aspects of the US Army Corps of

Engineers (USACE) and the US Environmental Protection Agency (EPA) ocean dumping programs for dredged material are directly affected by the United States

being signatory to the LDC. Domestic criteria must, at a minimum, be equivalent to and contain all of the basic constraints set forth in the iuternational regulations.

A Scientific Group (SG) was formed to make technical and scientific

recommendations to the LDC concerning the ecological aspects of regulating

dumping at sea. The SG met in September 1977 and has since met annually

approximately 6 months prior to each annual LDC meeting.

Intersessional working groups of experts meet on an ad hoc basis to

develop special guidelines, to discuss legal implications, and to intensely

evaluate new approaches to the technical aspects of the international regulations. Examples are groups to develop guidance for incineration at sea,

guidelines for the implementation of Annex III, guidance for allocation of

substances to the prohibited or special-care lists, and guidelines for the

application of the LDC annexes to disposal of dredged material.

The Deputy Director of Civil Works, USACE, and a representative of the

Assistant Secretary of the Army for Civil Works generally attend the annual

meetings of the LDC as Army policy representatives. The author is the Corps'

technical representative at LDC, SG, and special intersessional experts

meetings.

Application of the LDC

The signatory countries take all practical steps to prevent any pollution

of the sea that is liable to create hazards to human health, to harm living

resources and marine life, to damage amenities, or to interfere with other

legitimate uses of the sea (Article I of the LDC).

The construction of the LDC is simple and straightforward. The articles

that comprise the legal framework of the Convention develop the formal regulatory foundation. The annexes (i.e., Annex I - Prohibited Materials,

Annex II - Materials Requiring Special Care, and Annex III - Provisions for

Developing Regulatory Criteria) develop the technical framework for implementation of the articles. Interim technical guidelines for interpreting the

annexes of articles comprise the day-to-day working-level application of the

LDC. The simplicity ends here.

Many legal and technical terms and constraints were ill defined or even

undefined by the founders, leaving to the signatory countries the very difficult job of implementation through their domestic procedures. The LDC meets

annually and conducts business on a consensus basis after debating the issues

at hand. A vote is rarely taken and is regarded as the choice of last resort.

Issues, questions, legal and technical positions, rule changes, modifications,

or proposals can be submitted to the annual consultative meetings only by member nations and debated and acted upon by said member nations. Technical and

362
legal issues can also be referred to intersessional groups for further study

or resolution. The LDC is an active and dynamic treaty organization that

tries to incorporate the state of the art in its deliberations while remaining

responsive to many opposing views regarding ocean disposal.

Activities from LDC VIII to LDC X

LDC VIII met in February 1984 and endorsed comprehensive Annex III Implementation Guidelines for all material proposed for ocean disposal. The structure of the Annex III Guidelines includes the following sections:

Section A - Characteristics and Composition of the Matter.

Section B - Characteristics of Dumping Site and Method of Deposit.

Section C - General Considerations and Conditions.

The LDC VIII concluded that all parts of the Annex III Guidelines might not be

applicable to dredged material, tasked SG VIII to review this issue, and asked

member nations to submit technical proposals to SG VIII.

SC VIII met in March 1985, and the US submitted proposed Annex III Guidelines for dredged material. Discussion led to the consensus that special

guidance might be necessary, but the group could not agree on the final structure of and the absolute need for the guidelines. The SG VIII then recommended that an intersessional group of dredging experts meet to discuss the

need for and the structure of guidelines for dredged material disposal. The

expert group was proposed to meet in November 1985 (pending approval of LDC

IX) and consider guidelines for application of Annexes I, II, and III to

dredged material.

LDC IX met in September 1985 and agreed on the need for separate standalone dredged material guidelines for implementing the LDC annexes. The meeting approved an intersessional experts work group to develop the guidelines

and limited attendance to those nations that made technical submissions.

The Intersessional Work Group on Dredged Material met in November 1985

and developed and approved the technically acceptable Guidelines for the

Application of the Annexes to the Disposal of Dredged Material. The structure

of the dredged material guidelines is such that it replaces Section A of the

Annex III Guidelines and subsequently includes Sections B and C of the

Annex III Guidelines in their entirety. The sections of the dredged material

guidelines are: Introduction (Background); Conditions Under Which Permits for

Dumping of Dredged Material May Be Issued; Assessment of the Characteristics

and Composition of Dredged Material; and Disposal Management Techniques. The

dredged material guidelines are shown in their entirety in Appendix A of this

document.

The SG IX met in April 1986 and approved a slightly modified but technically acceptable version of the dredged material guidelines. The LDC X met

in October 1986 and unanimously approved the dredged material guidelines with

deletion of a minor section that did not legally comply with the LDC. The

adoption of the dredged material guidelines is considered a major

363

!J
breakthrough, where the unique characteristics of dredged material are recognized such that the regulation represents a holistic approach to contrasting

ocean disposal with land disposal alternatives.

The guidelines are founded on a comprehensive domestic and international

research base. These guidelines separate the regulation and assessment of

dredged material from that of sewage sludge and industrial wastes and include

exemptions and exclusions appropriate to dredged material. The guidelines

present the availability of ocean disposal management techniques and define

critical LDC terminology, "rapidly rendered harmless" and "special care," in

terms of a disposal management strategy.

The guidelines also require a review of alternatives to ocean disposal

through a comparative assessment of human health and environmental risks,

hazards (safety), economics, and exclusion of future uses of disposal areas.

Furthermore, the guidelines recognize that, for dredged material, "sea disposal is often an acceptable disposal option" and encourages productive/

beneficial uses such as marsh creation, beach nourishment, land reclamation,

or construction material.

Future Meetings

Future meetings of the LDC and SG will address the overall structure of

the annexes in regard to developing a waste management strategy that considers

all disposal media. Consideration will be given to the need for the existing

Annex I prohibited and Annex II special-care lists (black/gray lists) of substances proposed for ocean disposal. These lists are deemed quite arbitrary

and do not necessarily lead to adequate protection of the ocean or alternative

disposal environments.

ACKNOWLEDGMENT

This paper summarizes work carried out by the US delegation (USACE, EPA,

NOAA, DOE, DOD, DOT, and State Department) to the London Dumping Convention

(LDC VII, 1983; LDC VIII, 1984; LDC IX, 1985; and LDC X, 1986). The technical

basis was largely dependent on research investigations conducted under the

Dredged Material Research Program, Long-term Effects of Dredging Operations

Program, Field Verification Program, Dredgi.ig Operations Technical Support

Program, and field-reimbursable work funded by the US Army Corps of Engineers.

Permission to publish this material was granted by the Chief of Engineers.

REFERENCE

International Maritime Organization. 1986 (Oct). "Report of the Tenth Consultative Meeting of Contracting Parties to the Convention on the Prevention

of Marine Pollution of Dumping of Wastes and Other Matter," London, SEI.

APPENDIX A

The Guidelines are presented in their entirety in the following appendix

and form the general technical guidance, application, and interpretation of

the LDC Annexes as they apply to the ocean disposal of dredged material.

364
GUIDELINES FOR THE IMPLEMENTATION AND

UNIFORM INTERPRETATION OF ANNEX III

TO THE LONDON DUMPING CONVENTION

and

FOR THE APPLICATION OF THE ANNEXES TO THE DISPOSAL

OF DREDGED MATERIAL

Article IV(2): Any permit shall be issued only after careful consideration of

all the factors set forth in Annex III, including prior

studies of the characteristics of the dumping site, as set

forth in Sections B and C of that Annex.

Annex III: Provisions to be considered in establishing criteria governing

the issue of permits for the dumping of matter at sea, taking

into account Article IV(2), include:

Interpretation:

Each authority or authorities designated in accordance with Article VI

for the issue of general and special permits for the disposal of wastes and

other matter at sea shall, when considering a permit application, carefully

study all the factors set out in Annex III. This includes the establishment

of procedures and criteria for:

I deciding whether an application for sea disposal should be pursued

in the light of the availability of land-based disposal or treatment

methods;

2 selecting a sea disposal site, including the choice and collection

of relevant scientific data to assess the potential hazards to human

health, harm to living resources and marine life, damage to amenities, or interference with other legitimate uses of the sea.

A - CHARACTERISTICS AND COMPOSITION OF THE MATTER

1 INTRODUCTION

1.1 In accordance with Article IV(1)(a) of the Convention, Contracting

Parties shall prohibit the dumping of dredged material containing substances

listed in Annex I unless the dredged material can be exempted under paragraph 8 (rapidly rendered harmless) or paragraph 9 (trace contaminants) of

Annex I.

1.2 Furthermore, in accordance with Article IV(1)(b) of the Convention, Contracting Parties shall issue special permits for the dumping of dredged

365
material containing substances described in Annex II and, in accordance with

Annex II, shall ensure that special care is taken in the disposal at sea of

such dredged material.

1.3 In the case of dredged material not subject to the provisions of Articles IV(1)(a) and IV(1)(b), Contracting Parties are required under Article IV(1)(c) to issue a general permit prior to dumping.

1.4 Permits for the dumping of dredged material shall be issued in accordance

with Article IV(2), which requires careful consideration of all the factors

set forth in Annex III. In this regard, the Eighth Consultative Meeting, in

adopting Guidelines for the Implementation and Uniform Interpretation of

Annex III (resolution LDC.17(8)), resolved that Contracting Parties shall take

full account of these Guidelines in considering the factors set forth in that

Annex prior to the issue of any permit for the dumping of waste and other

matter at sea.

1.5 With regard to the implementation of paragraphs 8 and 9 of Annex I to the

Convention, the Fourth Consultative Meeting adopted Interim Guidelines

(LDC IV/12, Annex 5) which provide advice concerning the conditions under

which permits may be issued for dumping wastes containing Annex I substances,

and concerning the evaluation of the terms "trace contaminants" and "rapidly

rendered harmless."

1.6 Notwithstanding the general guidance referred to in paragraphs 1.4 and

1.5 above, subsequent deliberations by Contracting Parties have determined

that the special characteristics of dredged material warrant separate guidelines to be used when assessing the suitability of dredged material for disposal at sea. Such guidelines would be used by regulatory authorities in the

interpretation of paragraphs 8 and 9 of Annex I, and in the application of the

considerations under Annex III. These Guidelines for the Application of the

Annexes to the Disposal of Dredged Material have been prepared for this purpose and, more specifically, are intended to serve the following functions:

.1 to replace the Interim Guidelines for the implementation of paragraphs 8 and 9 of Annex I as they apply to dredged material; and

.2 to replace section A of the Guidelines for the Implementation and

Uniform Interpretation of Annex III (resolution LDC.17(8)).

2 CONDITIONS UNDER WHICH PERMITS FOR DUMPING OF DREDGED MATERIAL MAY BE

ISSUED

2.1 A Contracting Party may, after consideration of the factors contained in

Annex III, issue a general permit for the dumping of dredged material if:

.1 although Annex I substances are present, they are either determined

to be present as a "trace contaminant" or to be "rapidly rendered

harmless"; and

366
.2 the dredged material contains less than significant amounts* of substances listed in part A of Annex II and meets the requirements of

part C of Annex II.

2.2 If the conditions under 2.1.2 above are not met, a Contracting Party may

issue a special permit provided the condition under 2.1.1 has been met. Such

a special permit should either prescribe certain special care measures and/or

give limiting conditions to diminish the pollution source.

2.3 The assessment procedures and tests described in the following sections

are considered to apply equally to the interpretation of "harmlessness" (paragraph 8 of Annex I) and "trace contaminants" (paragraph 9 of Annex I) when

applied in association with sections B and C of the Annex III guidelines.

3 ASSESSMENT OF THE CHARACTERISTICS AND COMPOSITION OF DREDGED MATERIAL

This section replaces the Guidelines for the Implementation and Uniform

Interpretation of Annex III, part A, and provides an interpretation for the

assessment of dredged material. It should be considered in conjunction with

parts B and C of the Guidelines on Annex III.

I Total amount and average composition of matter dumped (e.g. per

year).

2 Form, e.g., solid, sludge, liquid, or gaseous.

For all dredged material to be disposed of at sea, the following

information should be obtained:

- gross wet tonnage per site (per unit time)

- method of dredging

- visual determination of sediment characteristics

(clay-silt/sand/gravel/boulder)

The following interpretations of "significant amounts" were agreed to by

the Eighth Consultative Meeting:

Pesticides and their by-products

not covered by Annex I and

lead and lead compounds: 0.05% or more by weight

All other substances in Annex II,

paragraph A: 0.1% or more by weight

367
In the absence of appreciable pollution sources, dredged material may be

exempted from the testing referred to in these Guidelines in the following

section if it meets one of the criteria listed below; in such cases the provisions of Annex III, sections B and C, should be taken into account:

.1 Dredged material is composed predominantly of sand, gravel or rock

and the material is found in areas of high current or wave energy

such as streams with large bed loads or coastal areas with shifting

bars and channels;

.2 Dredged material is for beach nourishment or restoration and is composed predominantly of sand, gravel, or shell with particle sizes

compatible with material on the receiving beaches; and

.3 In the absence of appreciable pollution sources, dredged material

not exceeding 10,000 tonnes per year from small, isolated and single

dredging operations, e.g. at marinas or small fishing harbors, may

be exempted. Larger quantities may be exempted if the material proposed for disposal at sea is situated away from known existing and

historical sources of pollution so as to provide reasonable assurance that such material has not been contaminated.

3 Properties: physical (e.g. solubility and density), chemical

and biochemical (e.g. oxygen demand, nutrients) and biological

(e.g. presence of viruses, bacteria, yeasts, parasites).

For dredged material that does not meet the above exemptions, further

information will be needed to fully assess the impact. Sufficient information

may be available from existing sources, for example from field observations on

the impact of similar material at similar sites or from previous test data on

similar material tested not more than five years previously.

In the absence of this information, chemical characterization will be

necessary as a first step to estimate gross loadings of contaminants. This

should not mean that each dredged material should be subjected to exhaustive

chemical analysis to establish the concentrations of a standard wide-ranging

list of chemical elements or compounds; knowledge of local discharges or other

sources of pollution, supported by a selective analysis, may often be used to

assess the likelihood of contamination. Where such an assessment cannot be

made, the levels of Annex I and I substances must be established as a

minimum.

Where this information, coupled with knowledge of the receiving area,

indicates that the material to be dumped is substantially similar in chemical

and physical properties to the sediments at the proposed disposal site, testing described in the following section might not be necessary.

Where chemical analysis is appropriate, further information may also be

useful in interpreting the results of chemica: testing, such as:

- density;

368
- per cent solids (moisture content);

- grain size analysis (7 sand, silt, clay); and

- total organic carbon (TOG).

In addition, there are several other parameters which may facilitate the

interpretation of the behavior, fate, and effects of dredged material (e.g.

sediment transport, pollutant transformation, sediment mitigative properties).

Sampling of sediments from the proposed dredging site should represent

the vertical and horizontal distribution and variability of the material to be

dredged. Samples should be spaced so as to identify and differentiate between

non-contaminated and contaminated locations.

4 Toxicity.

5 Persistence: physical, chemical, and biological.

6 Accumulation and biotransformation in biological materials or

sediments.

The purpose of testing under this section is to establish whether the

disposal at sea of dredged material containing Annex I and II substances might

cause undesirable effects, especially the possibility of chronic or acute

toxic effects on marine organisms or human health, whether or not arising from

their bioaccumulation in marine organisms and especially in fooe species.

The following biological test procedures might not be necessary if the

previous characterization of the material and of the receiving area allows an

assessment of the environmental impact. If, however, the previous analysis of

the material shows the presence of Annex I or Annex II substances in considerable quantities or of substances whose biological effects are not understood,

and if there is concern for antagonistic or synergistic effects of more than

one substance, or if there is any doubt as to the exact composition or properties of the material, it may be necessary to carry out suitable biological

test procedures. These procedures should be carried out on the solid phase

with bottom dwelling macrofauna and may include the following:

- aLute toxicity tests;

- chronic toxicity tests capable of evaluating long-term sub-lethal

effects, such as bioassays covering an entire life cycle; and

- tests to determine the potential for bioaccumulation of the

substance of concern.

Substances in dredged material, when entering the marine environment,

may undergo physical and chemical alteration that directly affects the release, retention, transformation, and/or toxicity of these substances. This

369
shall be taken into particular account when carrying out the various tests

mentioned above and when interpreting the results of these tests for actual or

future dumping site conditions.

7 Susceptibility to physical, chemical, and biochemical changes

and interaction in the aquatic environment with other dissolved

organic and inorganic materials.

Contaminants in dredged material, after dumping, may be altered by physical, chemical, and biochemical processes to more or to less harmful substances. The susceptibility of dredged material to such changes should be

considered in the light of the eventual fate and effects of the dredged material. In this context, field verification of predicted effects is of considerable importance.

8 Probability of production of taints or other changes reducing

marketability of resources (fish, shellfish, etc.).

Proper dump site selection rather than a testing application is recommended. Site selection to minimize impact on commercial or recreational fishery areas is a major consideration in resource protection and is covered in

greater detail in section C2 of Annex I11.

4 DISPOSAL MANAGEMENT TECHNIQUES

4.1 Ultimately, the problems of contaminated dredged material disposal can be

controlled effectively only by control of point source discharges to waters

from which dredged material is taken. Until this objective is met, the problems of contaminated dredged material may be addressed by using disposal management techniques.

4.2 The term "disposal management techniques" refers to actions and processes

through which the impact of Annex I or Annex II substances contained in

dredged material may be reduced to, or controlled at, a level which does not

constitute a hazard to human health, harm to living resources, damage to amenities, or interference with legitimate uses of the sea. In this context they

may, in certain circumstances, constitute additional methods by which dredged

material containing Annex I substances may be "rapidly rendered harmless" and

which may constitute "special care" in the disposal of dredged riaterial containing Annex II substances.

4.3 Relevant techniques include the utilization of natural physical, chemical and biological processes as they affect dredged material in the sea; for

organic material these may include physical, chemical, or biochemical

degradation and/or transformation that result in the material becoming nonpersistent, non-toxic and/or non-biologically available. Beyond the considerations of Annex 111, sections B and C, disposal management techniques may

include burial on or in the seafloor followed by clean sediment capping,

370
utilization of geochemical interactions and transformations of substances in

dredged material when combined with seawater or bottom sediment, selection of

special sites such as in abiotic zones, or methods of containing the spoil in

a stable manner (including on artificial islands).

4.4 Utilization of such techniques must be carried out in full conformity

with other Annex III considerations such as comparative assessment of alternative disposal options, and these guidelines should always be associated with

post-disposal monitoring to assess the effectiveness of the technique and the

need for any follow-up management action.

B - CHARACTERISTICS OF DUMPING SITE AND METHOD OF DEPOSIT

Matters relating to dump site selection criteria are addressed in greater

detail in a study prepared by GESAMP* (Reports and Studies No. 16:

Scientific Criteria for the Selection of Waste Disposal Sites at Sea,

IMO 1982) which should be considered in conjunction with these

guidelines.

I Location (e.g. co-ordinates of the dumping area, depth and distance

from the coast), location in relation to other areas (e.g. amenity

areas, spawning, nursery and fishing areas and exploitable

resources).

Interpretation:

Basic site characterization information to be considered by national

authorities at a very early stage of assessment of a new site should include

the co-ordinates of the dumping area (latitude, longitude), as well as its

location with regard to:

- distance to nearest coastline

- recreational areas

- spawning and nursery areas

- known migration routes of fish or marine mammals

- sport and commercial fishing areas

- areas of natural beauty or significant cultural or historical

importance

* IMO/FAO/LNESCO/WMO/WNO/IAEA/UN/LNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution.

371
- areas of special scientific or biological importance (marine

sanctuaries)

- shipping lanes

- military exclusion zones

- engineering uses of seafloor (e.g. potential or ongoing seabed mining,

undersea cables, desalination or energy conversion sites)

2 Rate of disposal per specific period (e.g. quantity per day, per

week, per month).

Interpretation:

Although the amounts of matter to be dumped (e.g. per year) are considered under paragraph Al above, many operations, e.g. those related to dredging, are of shorter periods. In order to assess the capacity of the area for

receiving a given type of material, the anticipated loading rates (e.g. per

day) or in the case of existing sites, the actual loading rates (frequency of

operations and quantities of wastes or other matter disposed of at each

operation per time period) should be taken into consideration.

3 Methods of packaging and containment, if any.

4 Initial dilution achieved by proposed method of release.

Interpretation:

The data to be considered under this item should include information on:

- type, size and form of packaging and containment units

- presence of any Annex I or Annex II substances as packaging material

or in any matrix that might be used

- marking and labelling of packages

- disposal method (e.g. jettisoning over ship's side; discharge of

liquids and sludges through pipes, pumping rates, number and location

of discharge pipe outlets (under or above waterline, water depth,

etc.)). In this connexion the length and speed of the vessel when

discharging wastes or other matter should be used to establish the

initial dilution

372
5 Dispersal characteristics (e.g. effects of currents, tides and wind

on horizontal transport and vertical mixing).

6 Water characteristics (e.g. temperature, pH, salinity, stratification, oxygen indices of pollution - dissolved oxygen (DO), chemical

oxygen demand (COD), biochemical oxygen demand (BOD) - nitrogen

present in organic and mineral form including ammonia, suspended

matter, other nutrients and productivity).

Interpretation:

For the evaluation of dispersal characteristics, data should be obtained

on the following:

- water depths (maximum, minimum, mean)

- water stratification in various seasons and weather conditions (depth

and seasonal variation of pycnocline)

- tidal period, orientation of tidal ellipse, velocities of minor and

major axis

- mean surface drift (net): direction, velocity

- mean bottom drift (net): direction, velocity

- storm (wave)-induced bottom currents (velocities)

- wind and wave characteristics, average number of storm days per year

- concentration and composition of suspended solids

Where the chemical composition of the waste warrants, it may be appropriate to evaluate pH, suspended solids, persistent organic chemicals, metals,

nutrients and microbiological components. BOD and COD or organic carbon

determinations in the suspended or dissolved phase, together with oxygen measurements, may also be appropriate where organic wastes or nutrients are

concerned.

7 Bottom characteristics (e.g. topography, geochemical and geological

characteristics and biological productivity).

Interpretation:

Maps and bathymetric charts should be consulted, and specific topographic

features which may affect the dispersal of wastes (e.g. marine canyons) should

be identified.

373
The geochemical observations of sediments in and around the disposal

site should be related to the type of waste(s) involved. The range of chemical constituents should be the same as that provided for the characterization

of the waste or other matter, with the minimum range of data set out in paragraph Al above.

In areas where wastes may reach the bottom, sediment structure (i.e. the

distribution of gravel, sand, silt and clay) as well as benthic and epibenthic

community characteristics should be considered for the site area.

Mobility of sediments due to waves, tides or other currents should be

considered in any waste disposal site assessments. The possibility of seismic

activities in the area under consideration should be investigated, in particular when hazardous wastes in packaged form are concerned. The distribution of

sediment types in an area provides basic information as to whether dumped

solids with certain characteristics will accumulate at a site or be dispersed.

Sorption/desorption processes under the range of dump site redox and pH

conditions, with particular reference to exchanges between dissolved and fine

particulate phases, are relevant to the evaluation of the accumulative properties of the area for the components of the waste proposed for dumping and for

their potential release to overlying waters.

8 Existence and effects of other dumpings which have been made in the

dumping area (e.g. heavy metal background reading and organic carbon

content).

Interpretation:

The basic assessment to be carried out of a site, either a new or an

existing one, shall include the consideration of possible effects that might

arise by the increase of certain waste constituents or by interaction (e.g.

synergystic effects) with other substances introduced in the area, either by

other dumpings or by river input and discharges from coastal areas, by exploitation areas, and maritime transport as well as through the atmosphere. The

existing stress on biological communities as a result of such activities

should be evaluated before any new or additional disposal operations are

established. The possible future uses of the sea.area should be kept under

consideration.

Information from baseline and monitoring studies at already established

dumping sites will be important in this evaluation of any new dumping activity

at the sand site or nearby.

9 In issuing a permit for dumping, Contracting Parties should consider

whether an adequate scientific basis exists for assessing the consequences of such dumping, as outlined in this Annex, taking into

account seasonal variations.

374 Engler - 14
Interpretation:

When a given location is first under consideration as a candidate disposal site, the existing data basis should be evaluated with a view to establishing whether the main characteristics are known in sufficient detail or

accurately enough for reliable modelling of waste effects. Many parameters

are so variable in space and time that a comprehensive series of observations

have to be designed to quantify the key properties of an area over the various

seasons.

If at any time, monitoring studies demonstrate that existing disposal

sites do not satisfy these criteria, alternative disposal sites or methods

should be considered.

C - GENERAL CONSIDERATIONS AND CONDITIONS

1 Possible effects on amenities (e.g. presence of floating or stranded

material, turbidity, objectionable odour, discolouration and

foaming).

2 Possible effects on marine life, fish and shellfish culture, fish

stocks and fisheries, seaweed harvesting and culture.

Interpretation:

Particular attention should be given to those waste constituents which

float on the surface or which, in reaction with seawater, may lead to floating

substances and which, because they are confined to a two-dimensional rather

than a three-dimensional medium, disperse very slowly. The possibility of

reaccumulation of such substances caused by the presence of surface convergences which may lead to interferences with amenities as well as with fisheries and shipping should be investigated.

Information on the nature and extent of commercial and recreational

fishery resources and activities should be gathered.

Body burdens of persistent toxic substances (and, in the case of shellfish, pathogens) in selected marine life and, in particular, commercial food

species from the dumping area should be established.

Certain grounds although not in use for fishing may be important to fish

stocks as spawning, nursery or feeding areas, and the effects of sea disposal

on these grounds should be considered.

The effects which waste disposal in certain areas could have on the habitats of rare, vulnerable or endangered species should be recognized.

375
Besides toxicological and bioaccumulation effects of waste constituents,

other potential impacts on marine life, such as nutrient enrichment, oxygen

depletion, turbidity, modification of the sediment composition and blanketing

of the seafloor, should be addressed.

It should also be taken into account that disposal at sea of certain substances may disrupt the physiological processes used by fish for detection and

may mask natural characteristics of seawater or tributary streams, thus confusing migratory species which consequently lose their direction, go unspawned

or fail to find food.

3 Possible effects on other uses of the sea (e.g. impairment of water

quality for industrial use, underwater corrosion of structures,

interference with ship operations from floating materials, interference with fishing or navigation through deposit of waste or solid

objects on the seafloor and protection of areas of special importance

for scientific or conservation purposes).

Interpretation:

Consideration of possible effects on the uses of the sea as outlined in

paragraph C3 should include interferences with fishing, such as the damaging

or fouling of fishing gear. Any possibility of excluding the future uses of

the sea dumping area for other resources, such as water use for industrial

purposes, navigation, erection of structures, mining, etc., should be taken

fully into account.

Areas of special importance include those of interest for scientific

research or conservation areas and distinctive habitats of limited distribution (such as seabird rookeries, kelp beds or coral reefs); information should

also be provided on all distinctive habitats in the vicinity of the proposed

site which might be affected by the material to be dumped. Attention should

also be given to geological and physiographical formations of outstanding

universal value from the point of view of science, conservation or natural

beauty.

4 The practical availability of alternative land-based methods of

treatment, disposal or elimination, or of treatment to render the

matter less harmful for dumping at sea.

Interpretation:

Before considering the dumping of matter at sea every effort should be

made to determine the practical availability of alternative land-based methods

of treatment, disposal or elimination, or of treatment to render the matter

less harmful for dumping at sea.

376
The practical availability of other means of disposal should be considered in the light of a comparative assessment of:

- human health risks

- environmental costs

- hazards (including accidents) associated with treatment, packaging,

transport and disposal

- economics (including energy costs)

- exclusion of future uses of disposal areas

for both sea disposal and the alternatives.

If the foregoing analysis shows the ocean alternative to be less preferable, a license for sea disposal should not be given.

In the special case of dredged materials, sea disposal is often an

acceptable disposal option, though opportunities should be taken to encourage

the productive use of dredged material for, for example, marsh creation, beach

nourishment, land reclamation or use in aggregates. For contaminated dredged

materials, consideration should be given to the use of special methods to mitigate their impact, in particular with respect to contaminant inputs. In

extreme cases of pollution, containment methods (including land-based disposal) may be required, but very careful consideration should be given to the

comparative assessment of the factors listed above before this option is pursued. Further advice on the management of contaminated dredged materials is

given in the Guidelines for the Application of the Annexes to the Disposal of

Dredged Material adopted by the Tenth Consultative Meeting by Resolution LDC

23(10).

377
AD-P006 -848 1111 I 11 1! 11111 111111 ll illll Jll 

"-. REGIONAL DEMONSTRATION OF BENEFICIAL USES OF

EXCAVATED MATERIAL IN THE CHESAPEAKE BAY

H. G. Earhart

US Army Engineer District, Baltimore

PO Box 1715

Baltimore, Maryland 21203-1715

ABSTRACT

The National Marine Fisheries Service (NMFS) and

the Corps of Engineers have cooperatively developed

and implemented regional demonstrations of beneficial

uses of excavated material using two Baltimore District Federal maintenance dredging projects. At the

Slaughter Creek, Dorchester County, Maryland, Federal

project, the excavated material and the contractorprovided oyster shell cultch was used to rehabilitate

an existing unproductive oyster bar. At the Twitch

Cove, Smith Island, Somerset County, Maryland, Federal

project, the excavated material and a wave-energy dissipating structure called a Longard tube were used to

create a submersed aquatic eelgrass (Zostera sp.) bed

in a moderately high-energy area. The Slaughter Creek

and Twitch Cove projects were completed in July 1987.

The submersed aquatic grass bed associated with the

Twitch Cove project was transplanted in September

1987. The success of both projects will be monitored

in fall 1987 and spring 1988.

INTRODUCTION

The Chesapeake Bay region has recently received national attention in the

form of Federal funding for a multistate resource management program. The

Corps of Engineers continues to participate with the environmental community

in endorsing the objectives of the initiative and the legislative mandates of

the Corps programs (Cole and Brainard 1978).

Background

Historically, the Baltimore District, Corps of Engineers, has made beneficial use of excavated material in a variety of applications, including beach

nourishment, shore erosion protection and stabilization, wetland and bird

habitat development, and sand dune creation (Earhart, in press). The applications of the concept have verified the advantages, which are costeffectiveness, environmental enhancement, long-term placement site potential,

reliable channel maintenance and project programming, and finally, public

acceptance.

92-16031 378

I IN I II IIII III
In January 1986, the National Marine Fisheries Service requested the

Corps of Engineers to evaluate the potential for shellfish habitat development

in the Chesapeake Bay using excavated material. As a result, an interagency

working group was established in June 1986 to develop a proposal implementing

the beneficial use concept as part of the Corps' maintenance dredging program.

Members of this interagency working group are listed below.

a. National Marine Fisheries Service, Washington, D. C.

b. National Marine Fisheries Service, Oxford, Md.

c. Maryland Department of Natural Resources, Annapolis, Md.

d. Corps of Engineers

(1) Water Resource Support Center, Fort Belvoir, Va.

(2) North Atlantic Division, New York, N.Y.

(3) Baltimore District, Baltimore, Md.

(4) Norfolk District, Norfolk, Va.

e. Maryland Port Administration, Baltimore, Md.

f. Virginia Marine Resource Commission, Newport News, Va.

The current maintenance dredging program was reviewed, and a list of

potential dredging projects was scrutinized for potential implementation. In

January 1987, the proposal was endorsed by the Corps of Engineers and the

National Marine Fisheries Service. The endorsement represented an opportunity

to implement the beneficial use concept f or application on a national level

and to document the continued effort to environmentally enhance the Corps'

maintenance dredging program.

Site Selection

The interagency working group selected two Federal maintenance dredging

projects for the beneficial use demonstrations. The Slaughter Creek Federal

channel is located in Dorchester County, Maryland (USAED, Baltimore 1980).

The waterway separates Taylors Island, Maryland, from the mainland, which is

approximately 20 miles southwest of Cambridge. The other site is located at

the Federal channel at Twitch Cove, Smith Island, Somerset County, Maryland

(Figure 1). Smith Island is approximately 20 miles west of Crisfield, Md.

SLAUGHTER CREEK PROJECT

The authorized project dimensions for the Slaughter Creek channel are

7 ft deep, 100 ft wide, and approximately 2,000 ft long (Figure 2). The

channel was last dredged in 1981. The previously used placement option was a

10-acre upland site approximately 1 mile west of the channel.

The proposed beneficial use placement site is a 100-acre open-water site

approximately 1 mile northeast of the channel. The area is a Maryland-charted

379
CORPS OF ENGINEERS U. S. ARMY

SLAGHTR REE, DRCESTERRAi

Figure00UTY 1.R ChspaeLoAtiNDma

380ý - -
CORPS OF ENGINEERS U S. ARMY

A N EXCAVATED MATERIAL

G t. H 0 P, PLACEMENT SITE

YUSED CHANNEL TO BE EXCAVATED

PLACEMENT SITE (7'd x 100iw x 2000'I)

10 ACRES) --

f P"1E. LIMT O

FtEDERAL PROJECT

ft -t

VLORS

0 06 

0

SLAUGHTER CREEK, MD.

REVISEO SEPTEM8EA 1985

Figure 2. Slaughter Creek project map

381
public oyster bar (Maryland Department of Tidewater Fisheries 1983). However,

the bar is unproductive due to unstable and unsuitable substrate conditions

for oyster reproduction.

Approximately 16,863 yd3 of material was removed and deposited in the

open-water placement site. The channel sediments were composed of 60 percent

fine sand and 40 percent silts (Figure 3).

Beneficial Use Demonstration

Slaughter Creek Proposed Plan

ro 12 Inch Hydraulic Dredge

Disch.irqe Pipe co

c-o -o 0

> ~0 C

8 Inch Oyster Shell Cap Excavated

Material Mound

Channel Excavation -- - -------- 300 Fi-.j Shell Area = 2.1 Acres

Quantity 14 1 17 Cubic Yaids "600 . -- Ft ,S Channel Sediment

Not To Scale Plan View composition = 60% Fine Sand

40% Silt

Figure 3. Slaughter Creek conceptual plan

The existing unsultaSle bottom was stabilized with the excavated material. An 8-in. oyster shell cap was placed on top of the excavated material

as cultch to encourage oyster larvae settlement. Upon completion of the project, a 2.1-acre unproductive charted oyster bar was rehabilitated and is expected to provide an acceptable bottom for the oyster spawning season

beginning in late June 1987.

A monitoring plan has been developed to determine the amount of shell

that is lost due to burial into the newly created bottom. This will be accomplished by analyzing hydrographic survey data, shell depth, exposed shell, and

spat surveys in the fall of 1987 and spring of 1988. Construction was completed in June 1987.

One of the advantages of the beneficial use concept is the costeffectiveness of the concept. A cost savings of 46 percent was documented at

Slaughter Creek (Table 1).

TWITCH COVE PROJECT

The second site selected was the Federal project at Twitch Cove. The

authorized channel is 7 ft deep, 60 ft wide, and approximately 5,000 ft long

382
TABLE 1. SLAUGHTER CREEK PROJECT ECONOMICS

Feature Historical* Current** Savings

Placement $67,452 $48,280 $19,172

($4.00/yd 3 ) ($2.86/yd 3 )

Dike construction $48,000 0 --

Shell cap 0 $21,435 $26,565

Mobilization/

demobilization $49,200 $20,000 $29,200

Total $164,652 $89,715 $74,937

(46%)

* Based on 1981 Slaughter Creek low bidder's price (updated to

March 1987 costs).

** Based on April 1987 low bidder's price for the Slaughter

Creek project.

(Figure 4). The previously used placement site was a 15-acre upland site

northwest of the channel. The proposed placement site is located south and

approximately 5,000 ft from the channel.

Historically, there has been an abundance of submersed aquatic grass

Zostera marina (eelgrass) along the eastern coast of Smith Island (Orth et al.

1985). The placement site is currently one of the few areas along the coast

that lacks eelgrass. One hypothesis for the lack of eelgrass in the placement

site is that the wave energy may be too strong to allow the immature plants to

become established and that the area may exceed the optimum depth required for

the growth of eelgrass.

The conceptual plan was based on alleviating the conditions as previously

hypothesized. A wave-dissipating structure called a Longard tube was filled

with sand from a barge and strategically placed to break the predominant wave

energies (Longard Corporation 1983) (Figure 5). The remaining excavated material was placed behind the wave-dampening structures to decrease existing

water depths to encourage submersed aquatic grass stabilization.

Placement of the excavated material and filling of the tubes were completed in July 1987. The 3-acre area of Z. marina was transplanted in

September 1987.

The Longard tubes and the transplants will be monitored twice during the

growing season. Submersed aquatic vegetation density, survival, and general

condition will be measured. A savings of $22,586, approximately 7 percent of

the 1981 project costs, was documented for the Twitch Cove project (Table 2).

383
SA- Ia * u

0~~1U1 42,OAT gOQ

$ANa -s N

EST~ PREVIOUSLY USED.ZPLACEMENT SITE -

- N~2 (15 ACRES)

/ - - CHANNEL TO BE EXCAVATED'

£ ~ XAATED X M -MATERIAL

£ ~ Y. PLCEMNT SITE

_A C C 0 INAs I - I RTL G N A

j\~ K~7TWITCH COVE AND

50 - BIG THOROFARE RIVER, MO)

SOUNDINGS A~f~ N Fffr

Figure 4. Twitch Cove project map

384
Beneficial Use Demonstration

Twitch Cove Proposed Plan

Submerged Aquatic Vegetation (SAV)-3 Acres of Zostera Marina (Eelgrass)

A

DISCharge_________

F rom

Dredget io

and

Barged

S~hogei,ne ope

3 Acre Longerd Tubes

SAV0 )

,Channel Excavation Ouantity-24.395 Cubic Yards

Channel Sediment Composition-40% Fine Sand No4 To Sca•e

60% Silts

Figure 5. Twitch Cove conceptual plan

TABLE 2. TWITCH COVE PROJECT ECONOMICS

Feature Historical* Current** Savings

Placement $83,919 $64,680

($3.44/yd 3 ) ($2.65/yd 3 )

Plant modification 0 $50,345

Dike construction $100,000 0

Longard tubes 0 $23,580

Transplants 0 $57,900

Subtotal $183,919 $196,505 +$12,586

Mobilization/

demobilization $120,000 $84,828 $35,172

Total $303,919 $281,333 $22,586

(7%)

* Based on 1981 Twitch Cove low bidder's pLice (updated to March

1987 costs).

** Based on May 1987 low bidder's price for the Twitch Cove

project.

385
CONCLUSIONS

The beneficial use of excavated material is an innovative concept that is

economically attractive, enhances the environment, and provides environmentally acceptable placement sites. The Baltimore District and the environmental community of the Chesapeake Bay will continue to pursue beneficial uses of

excavated material.

REFERENCES

Cole, James, and Brainard, Michael. 1978. "Evaluation of Laws and Regulations Impacting the Land Use of Dredged Material Containment Areas," Technical

Report D-78-55, prepared by Science Applications, Inc., La Jolla, Calif., for

US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Earhart, H. Glenn. In press. "Beneficial Uses of Excavated Material in the

Chesapeake Bay," Proceedings of the Regional Conference on the Beneficial Uses

of Dredged Material, USAED, Baltimore, Baltimore, Md.

Longard Corporation. 1983. "Longard Tube Applications Manual," Fredericksburg, Va.

Maryland Department of Tidewater Fisheries. 1983. "Natural Oyster Bar,"

Chart 15, Annapolis, Md.

Orth, Robert, et al. 1985. "Distribution of Submerged Aquatic Vegetation in

the Chesapeake Bay and Tributaries," Virginia Institute of Marine Sciences,

Gloucester Point, Va.

US Army Engineer District, Baltimore. 1980. River and Harbor Project Map

Book, Maps 32 and 53, Baltimore, Md.

/

'•••.•386
JAPANESE CLOSING REMARKS

13th US/JAPAN EXPERTS MEETING

T. Nishimura

Director, Environment Division

Bureau of Ports and Harbours

Ministry of Transport, Japanese Government

Tokyo, Japan

I would like to say a few words as the Japanese Co-Chairman. First, I

would like to express our gratitude to Co-Chairman COL Richard Rothblum, to

Mr. Hamons, members of the Corps of Engineers, and those who coordinated and

managed this US/Japan Experts Meeting so smoothly. I think the 13th US/Japan

Experts Meeting has been very successful and fruitful. It has been an honor

for me to serve as Co-Chairman.

I would like to express my personal thoughts briefly. It is regrettable

that bottom sediments contain a multitude of toxic materials, including heavy

metals, PCBs, and by-products of industry in many harbor areas, waterways, and

lakes in both our countries. Many efforts have been funded to manage contaminated bottom sediments.

In Japan, the system that regulates dredging projects (including acts,

regulations, budgeting, etc.) was established in 1972. During fiscal years

1972-1986, Japanese municipal governments completed or continued 37 projects

involving contaminated bottom sediments, at a cost of more than $800 million

(US). I have been personally involved with the Minamata project--the largest

harbor area restoration project in Japan. This project is scheduled for completion in March 1990.

It will take over 10 years to complete the contaminated bottom sediment

management program that has been outlined for the harbor areas, waterways,

rivers, and lakes of Japan. A great deal of time, money, and effort will be

expended.

I think that there are points of similarity and nonsimilarity between the

contaminated bottom sediment management projects of the USA and Japan. A similar point is that a major portion of the effort has been directed toward convincing concerned organizations and area residents as to the value and safety

of dredging projects. A point of nonsimilarity is represented by the environmental regulation systems of our countries, both for the purpose of observing

the London Dumping Convention, as mentioned by Dr. Robert Engler.

In spite of the level of US and Japanese expertise, I think we must continue to pursue a highly advanced technology (including planning, design, execution, and monitoring) to manage contaminated bottom sediments successfully.

In this sense, it is very important to continue the US/Japan Experts Meeting

for the exchange of technical information. I have been pleased to learn that

Co-Chairman COL Rothblum, Mr. Murden, and many other US engineers also share

this opinion.

387
We shall hold the next meeting in November 1989 in Japan. I anticipate

that many Japanese mayors would like to host the meeting in their city, so I

shall choose carefully. In conclusion, I would hope that many of the engineers who attended the 13th US/Japan Experts Meeting will visit Japan in

November 1989.

Thank you for your attention.

388

388