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OCR for page 280
REMEDIAL TECHNOLOGIES USED AT
INTERNATIONAL JOINT COMMISSION AREAS OF CONCERN
Ian Orchard
Environment Canada
ABSTRACT
This paper discusses the need for various technological
options for the remediation of contaminated sediments in 39
of 42 nearshore areas in the Great Lakes basin. These areas
have been designated as "areas of concern" by the Interna-
tional Joint Commission, established by the United States
and Canada for the restoration and enhancement of water
quality in the Great Lakes. There are three broad cate-
gories of options for dealing with contaminated sediments
leave them alone, remediate in situ, or dredge them. No
technologies are presently available within the Great Lakes
basin that can be used to remediate; the only real action
alternative based on available technology is to dredge up
contaminated sediments.
Although considerable experience and technology is
available to dredge large volumes of sediment, the disposal
~ ~ ~ ~ ~ . Presently, only shore-
oase~, confined d' sposal facilities and upland landfill dis-
posal of the entire volume of dredge material appear to be
possible for large-scale operations. The lack of available
space to build confined facilities and to locate landfills
has resulted in an urgent need for the development of alter-
native techniques.
Some concentration (separation), inactivation, and des-
truction techniques are operational elsewhere in the world
but they remain largely at the laboratory (bench) scale or
pilot-scale stages in the Great Lakes. Consequently, the
focus of this paper will be upon the work of the sediment
subcommittee of the International Joint Commission in the
identification of appropriate remedial technologies for con-
0t this material remains a problem
will be upon the work of
laminated sediment
BACKGROUND
The government of Canada and the United States signed the Boundary
Waters Treaty on January 11, 1909, which outlined the rights of each
country in the use of Great Lakes waters. In the 1960s, growing public
concern about the quality of water in the lower Great Lakes resulted in
280
OCR for page 281
281
studies by both governments aimed at assessing the nature and extent of
water quality degradation. As a consequence of these studies, Canada
and the United States entered into agreements in 1972 and 1978 on Great
Lakes water quality aimed at restoration and enhancement of water
quality.
An International Joint Commission (UC) established under the Boun-
dary Waters Treaty functions as the administrative mechanism for ensur-
ing compliance between the parties under the agreement. In 1987 a pro-
tocol amending the 1978 agreement was signed between the governments.
This protocol placed a greater emphasis on the governments to undertake
specific initiatives so as to address the continuing contamination of
the Great Lakes. The IJC has assumed a more evaluative role in ensur-
ing that the parties meet the terms of the agreement. The U.S. Environ-
mental Protection Agency (EPA) is the main agency responsible for deli-
very of U.S. obligations under the agreement and Environment Canada
(DOE) is the main Canadian agency.
The development of remedial options for contaminated sediment dates
back to the dredging subcommittee of the IJC, which was created under
the Great Lakes Water Quality Agreement of 1978. At that time the com-
mittee's objectives were to develop guidelines and criteria for dredg-
ing activities, maintain a register of dredging projects, exchange
information on technology and research, and identify criteria for the
classification of polluted sediments in areas that were continually
dredged.
In 1986, the sediment subcommittee was created when it became clear
that one of the key elements in the development of remedial action
plans for areas of concern was the need to refine existing assessment
techniques for polluted sediment as well as identify implementable reme-
dial options for polluted sediment. Two work groups were created under
the sediment subcommi ttee . The remedial options work group produced a
draft report in November 1987. The report is currently being subjected
to scientific and technical review. Its objectives report are to
1. review existing technologies for the remediation of ecosystem
related impacts due to sediment contaminants;
2. evaluate the effectiveness and feasibility of existing technol-
og~es;
3. develop a system for evaluating the most applicable technology
to be used for remediating identified ecosystem impacts due to
sediment contamination in the nearshore areas of the Great Lakes
basin;
a. identify research needs to further test existing technologies or
establish new approaches to mitigate sediment contaminant
problems;
. establish in conjunction with the assessment work group and
other committees, work groups or task forces, as necessary, a
monitoring program to assess any adverse effects on the eco-
system that may result from moving or otherwise isolating
existing contaminated sediments from their present location.
OCR for page 282
282
REMEDIAL OPTIONS
The remedial options work group is evaluating remedial options for
polluted sediment using the following criteria:
1. Description of Options
· Stages associated with the implementation of the option (out-
line of the procedures involved)
· Is it currently used by jurisdictionts)?
· Has it been field validated?
· Specific case studies associated with the option (refer to
title or give short summary of findings)
Feasibility
Engineering/design feasibility
· Cost (engineering, not socioeconomic costs)
· Time frame, from conceptualization through implementation.
· Limitations--geographic, engineering, scientific, technical,
etc.?
· Can the option be implemented to deal with large-scale con-
tamination (harborwide or can it deal with a small area size
limitation)?
· Does this option deal with different degrees or ranges of
contamination?
3. Environmental/Regulatory Criteria
· What guidelines/criteria exist relative to the implementation
of this option?
· What assessment criteria are available during implementation
and for follow-up (how clean is clean)?
· Does any need exist to develop assessment criteria to address
this option's relative success?
i. Long-Term vs. Short-Term Management
· Is this a quick-fix option that can be implemented in the
short-term to deal with a hot spot?
· Is this a one-shot remedy that could preclude the use of
other options in the future?
· Does this option require long-term management (is its imple-
mentation incremental over a period of time)?
The options currently being evaluated are open-water disposal, cap-
ping in place, confined disposal, lake filling, agricultural land
spreading, strip mine reclamation, decontamination treatment, and sol-
idification. The options can be classified into the following cate-
gories based on available data and need for additional testing and
field validation:
· remedial options--commonly used techniques,
· remedial options--requiring some testing and assessment,
· remedial options--proposed and tested on a limited scale, and
· remedial options--some limitation and requiring more testing.
OCR for page 283
283
A suggested guide for readers to follow has also been developed
titled "Sediment Remedial Options" (Figure 1~. The guide suggests that
one should not consider implementing a remedial option before taking
steps to identify the nature and extent of contamination. The causes
of contamination can be identified on the basis of available (or col-
lected) baseline data. One must be careful not to propose remediation
measures which only address symptoms of contamination. It can be seen
from the options listed that we still have a lot of work to do. Most
of the options identified require validation and testing.
A short summary of the four categories of remedial options fol-
lows. This is a very cursory identification and categorization of
options. For a more detailed discussion of remedial technologies the
reader is asked to refer to Technologies for the Remediation of Con-
taminated Sediments in the Great Lakes; Report of the Sediment Subcom-
mittee and its Remedial Options Work Group to the Water Quality Board
of the International Joint Commission, July 1988.
Commonly Used Techniques
.
Dredging and disposal into confined disposal facilities (CDFs) con-
structed in the nearshore zone: estimated cost, $4, 00/yd3
(capital cost).
Dredging and disposal on agricultural land: filling of low-lying
agricultural land (material) must meet all regulatory require-
ments). Estimated cost, $0.50/yd3/mi (pumping), $185,000/
ml-pipe (capital cost that can be amortized over the life of
several projects), $0.45/yd3/mi (transport).
Remedial Options Requiring Some Testing and Assessment
Subaqueous confinement: field verification proved effectiveness of
this option in preventing the movement of contaminants into water
and biota.
Capping/covering in-place: suitable for low-energy zones in the
lake; contaminants isolated by cap material.
Beach nourishment: material must match beach substrate and must
not be erodable; documented for material containing a limited
quantity of nutrients . Estimated cost, $0. 50/yd3/mi, pump-
ing, $185,000/mi (pipe) capital cost.
Remedial Options Proposed and Tested on a Limited Scale
Depositional zone placement: minimum depth 30 m of 3 x maximum
wave height must stay in place. Estimated cost, $0.26/yd3/mi
(transportation).
Solidification: proven technique for treatment of industrial/
municipal wastes . Estimated cost $4S-75/yd3 of wastes (not
including cos t of removal and disposal).
OCR for page 284
284
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285
.
.
Dewatering and separation of sediment into coarse (clean) and fine
(contaminated) fraction using centrifuges and hydrocyclones.
1. Further treatment of contaminated fraction by acid leaching/ion
exchange (for metals), thermal treatment (for mercury), solvent
extraction (for PAHs and oil).
2. Re-use of decontaminated material or landfill disposal This
option reduces the volume of highly contaminated sediments but
involves a high initial cost for equipment.
Decontamination of PCB-contaminated sediments by low-temperature
oxidation, chlorine removal, pyrolysis, removing and concentrating,
vitrification, use of microorganisms or different chemical treat-
ments.
In situ containment of contaminated sediments by synthetic mem-
branes.
In situ chemical treatment and microbiological treatment.
Various biological treatments.
Some Limitations and Remedial Options Requiring More Testing
Hydraulic control navigation relocation: suitable for docking
slips/shipping channels; minimizes resuspension of contaminants
during shipping activities.
Reclamation of strip mines and quarries: proximity of site is the
major constraint, groundwater impact must be considered. Estimated
cost, $12.50/yd3/for 200 mi transportation.
Landfill: considered as a poor use of available expensive landfill
space. Estimated cost, $3.00/yd3 (disposal), $0.45/yd3/mi
transport to site).
Upland fill: Geographic limitations, availability of land, trans-
port to the site. Estimated cost, $0.50/yd3/mi (pumping),
$185,000/mi (pipe-capital cost).
The complexity associated with the selection of suitable remedial
options can be demonstrated by Table 1, which summarizes technologies
associated with PCB-contaminated sediment. The technologies listed
have been excerpted from PCB Sediment Decontamination: Technical/
Economic Assessment of Sel ected Al ternative Treatment, Research
Triangle Institute for the U.S. EPA, December 1986.
BASELINE MAPPING
Before deciding an an appropriate remedial option, one must know
the nature and extent of sediment contamination. Baseline mapping and
sampling of an area in question is essential. Mapping identifies the
geographic extent of sediment accumulation zones versus erosional
areas. This information allows for making loading calculations (once
the accumulation rate is known). Also, mapping leads to a subjective
OCR for page 286
286
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