Assessment and Remediation of Contaminated Sediments (ARCS) Program
Table of Content
- Chapter 1
- Chapter 2
- Chapter 3
- Chapter 4
- Chapter 5
- Chapter 6
- Chapter 7
- Chapter 8
- Chapter 9
- Chapter 10
- Chapter 11
- List of Figures
- List of Tables
Remediation Guidance Document
US Environmental Protection Agency. 1994. ARCS Remediation Guidance Document. EPA 905-B94-003. Chicago, Ill.: Great Lakes National Program Office.
Table of ContentsREMEDIAL PLANNING AND DESIGN
- DECISION-MAKING STRATEGIES
- ESTIMATING PROJECT COSTS
- ESTIMATING CONTAMINANT LOSSES
- REGULATORY AND LEGAL CONSIDERATIONS
This chapter presents general procedures for developing sediment remedial alternatives, evaluating their feasibility, estimating project costs, and estimating contaminant losses that may occur as a result of remediation activities. Before discussing these procedures, the decision-making strategies that may be applied to sediment remediation are examined. The chapter also summaries the various Federal laws and regulations that may be applicable to sediment remediation activities.
Decision-making strategies are pathways for approaching a complex issue or problem in a logical order or sequence. A strategy can be represented as a flow chart or framework of activities and decisions to be made. Decision-making strategies are usually developed for very specific applications. The management of contaminated sediments occurs for a variety of purposes other than environmental remediation and restoration. Other purposes include the construction and maintenance of navigation channels, the clearing of sediment deposits from water supply intakes, construction within waterways, and the operation and maintenance of reservoirs and impoundments for flood control, water supply, recreation, or other purposes. There is no single decision-making strategy for the management of contaminated sediments that suits all purposes. Two established strategies that have been applied to the management of contaminated sediments are 1) a technical management framework developed jointly by the U.S. Army Corps of Engineers (Corps) and USEPA and 2) the decision framework established for Superfund projects. These two strategies are discussed below.
The Corps and USEPA have developed a management framework for determining the environmental acceptability of dredged material disposal alternatives (USACE/USEPA 1992). This framework, shown in Figure 2-1, is structured to meet the regulatory requirements of the Clean Water Act; Marine Protection, Research and Sanctuaries Act; and the National Environmental Policy Act (NEPA). This framework was developed for the management of clean as well as contaminated dredged material and has evolved from earlier decision-making strategies (Francinques et al. 1985; Lee et al. 1991).
The Corps/USEPA management framework is a tiered decision-making process. Information about the sediments to be dredged is evaluated to determine the suitability of disposal alternatives in order of increasing complexity. Sediments that are determined to be uncontaminated are suitable for a wider variety of disposal options, and decisions can be made early in the evaluation process. Sediments that are contaminated require a more extensive evaluation within the decision-making framework, have additional testing requirements, and usually have fewer disposal options.
Corps regulations (33 CFR 230-250) require that this framework be used in the management of dredged material from navigation projects and in the administration of the permit program for dredged material disposal under section 404 of the Clean Water Act. The Corps/USEPA framework may be applicable to many sediment remediation projects; however, the process does not fully address sediment treatment technologies.
The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) and Superfund Amendments and Reauthorization Act of 1986 (SARA) established and reauthorized the Superfund Program. The decision-making framework for Superfund projects is shown in Figure 2-2 and is described in detail in USEPA (1988a).
The Superfund decision-making framework has two major components: the remedial investigation and the feasibility study (RI/FS). For a Superfund site with contaminated sediments, the remedial investigation would identify the character of the sediments and the extent of contamination, among other information. The feasibility study would include an evaluation of all reasonable remedial alternatives, including treatment and non-treatment options.
Either of the decision-making strategies discussed above might be applied to a sediment remediation project with equal success. These strategies represent two different approaches to the evaluation and selection of remedial alternatives. In the Superfund strategy, remedial alternatives are evaluated in a parallel fashion (Figure 2-3) (i.e., a wide range of possible alternatives are evaluated simultaneously, and then a selection is made among the leading candidates). Another possible strategy is a linear or sequential approach to evaluating disposal alternatives (Figure 2-3). Portions of the Corps/USEPA management framework use this approach, in which, for example, disposal options are examined in order of increasing complexity until a suitable alternative is found.
Each of these approaches has advantages and disadvantages. The advantages of the parallel approach over the sequential approach can be summarized as follows:
- The approach has been widely used for RI/FS efforts at Superfund sites contained in the National Priorities List (NPL) and at other non-Superfund sites
- Most environmental consultants and regulatory agencies are more familiar with this approach
- The approach is consistent with the requirements of NEPA
- The approach generally provides decision-makers with more than one option for consideration
The primary disadvantage of the parallel approach is that the evaluation of numerous alternatives may require significant resources and time.
Projects that are on the NPL are required to follow Superfund RI/FS procedures (the parallel approach). However, many (if not most) contaminated sediment sites, including the majority of AOCs in the Great Lakes, are not NPL sites. For projects where resources, funding, or time may not allow a detailed evaluation of numerous alternatives, a hybrid approach may be considered that incorporates elements of both the parallel and sequential approaches.
A simple decision-making framework for evaluating sediment remedial alternatives is shown in Figure 2-4, and contains elements of both of the decision-making strategies discussed above. This framework contains four major activities (boxes) and one decision point (diamond). The first activity is to define the objectives and scope of the project. The next two activities involve the screening and preliminary design of remedial alternatives. The products of these activities are preliminary designs, cost estimates, and estimates of contaminant loss, which are used to determine if there is a feasible alternative that meets the project objectives. If there is more than one alternative that meets these objectives, the preferred alternative is selected. If there are no feasible alternatives that meet the project objectives, the evaluator must return to the first activity to reevaluate the project objectives and/or scope. The final major activity, once a preferred alternative has been selected, is implementation. The elements of this decision-making framework are described in the following sections, preceded by a brief definition of several relevant terms used throughout this guidance document.
A sediment remedial alternative is a combination of technologies that is used in series and/or in parallel to alter the sediments or concentrations of sediment contaminants in order to achieve specific project objectives (discussed below). The simplest alternative would employ a single technology, such as in situ capping. However, a more complex alternative, as shown in Figure 2-5, may involve several different technologies and, in the process, generate a number of separate residues or waste streams.
A component is a phase of a remedial alternative, such as removal, transport, pretreatment, treatment, disposal, or residue management. Chapters 4-10 of this report discuss the available technologies for each of these components. Nonremoval technologies (e.g., in situ containment), which could be considered components or complete remedial alternatives, are discussed in Chapter 3.
For each component, several technology types may be considered. For example, the removal component could involve the use of hydraulic or mechanical dredges. A subcategory of a technology type, referred to as a process option, is a specific equipment item, process, or operation. For example, a horizontal auger dredge is a process option under the hydraulic dredge technology type of the removal component.
To simplify the use of this document, a key assumption is made that a decision to remediate contaminated sediments in some portion(s) of a river, channel, harbor, or lake has already been made. The reasons for that decision, although critical to the successful remediation of the impacted area, are not essential to the use of this guidance; however, the objectives of the remediation project will need to be established to guide the evaluation of remedial alternatives. In addition, the scope of the remediation effort will also have to be defined as clearly as possible.
The objectives of a sediment remediation project are usually designed to correct site-specific environmental problems. In some cases, the objective is in the form of a statement of the desired results to be achieved by remediation. In other cases, the objective may be defined in the authority under which the project is initiated. For example, the objective of the remedial action plans for the Great Lakes AOCs, as defined in the Great Lakes Water Quality Agreement, is to restore the beneficial uses of each area.
The objectives of a sediment remediation project can be quantitative, qualitative, or a combination of both. In some cases, the objectives are fully quantified, such as in the case of an enforcement action where the contaminated material is localized and its source is known (e.g., an illegal fill or spill). In such cases, the objective might be defined in quantitative terms, such as to remove sediments exceeding a specified level of contamination, or to remove a specific quantity of sediment. In this case, the objectives and scope of the project are virtually the same.
In many cases, however, sediment contamination is widely dispersed and the objectives of the remediation project are more qualitative. For example, an objective might be to reduce the human health risk caused by the consumption of fish contaminated by the sediments, or to enhance the diversity of aquatic life that is depressed by sediment contamination. Such objectives may become quantified by setting specific targets for remediation (e.g., fish tissue contaminant concentration).
The objectives of a sediment remediation project may be defined through risk analysis and modeling methods, as outlined in the ARCS Risk Assessment and Modeling Overview Document (USEPA 1993a). These methods can be used to determine the environmental impacts of the no action alternative as well as various remedial alternatives. When the objectives are established by risk assessment and modeling, the ability of remedial alternatives to meet these objectives can generally be determined using the same procedures.
Defining the objectives of a sediment remediation project is often a very complicated process, requiring coordination at many levels. It is not always possible to define specific, quantifiable objectives and proceed directly to the project design and construction stage. If there is more than one proponent for a remediation project, there may be different objectives, not all of which may be compatible or feasible. In this case, project objectives and scopes may need to be formulated in an iterative fashion, as shown in Figure 2-4. This approach is especially useful when the objectives are less certain or poorly quantified.
The scope of a sediment remediation project defines the extent of the remediation in terms of both space and time. The scope is generally an extension of the project objectives. The scope may be defined through detailed analysis, including risk assessment and modeling. It may be defined by statute or through a negotiated or adjudicated settlement. The scope may also be scaled to fit funding or other constraints through an iterative process, as shown in Figure 2-4.
The spatial scope of a sediment remediation project is typically defined as an area or reach of a river, channel, harbor, or lake. The scope may be defined in terms of sediment depth or thickness. For example, the project objective may be to decrease the level of contamination in fish to some threshold by reducing the exposure to sediment contaminants. The scope might then be defined as the creation, in a specific reach of river, of a new sediment surface with an acceptable level of contamination. This new sediment surface might be created by removing existing sediments, covering them, or treating them in place.
The objectives of a project may require that the scope include (or exclude) specific technologies. For example, project objectives may require the removal of contaminated sediments or the destruction of a particular contaminant. These restrictions may be mandated by authorizing legislation or applicable regulations.
The time element of a sediment remediation project may be fixed or open ended. Restrictions on the time to complete a remediation project can have significant effects on its feasibility and cost of implementation.
Screening of Technologies
Once the project objectives and scope have been defined, the next step in the decision-making framework (Figure 2-4) is the screening of technologies. The purpose of this step is to eliminate from further consideration technologies that are not feasible or practicable, using available information. This is best done by first attempting to eliminate broad categories of options and then focusing on technology types. In the simplest context, there are two forms of remediation (containment and treatment) that can be performed on contaminated sediments under two possible conditions (in place or excavated). These options create the following four modes of sediment remediation:
- Containment in place
- Treatment in place
- Excavation and containment
- Excavation and treatment
A summary of the containment and treatment technology types for these four modes of remediation is shown in Table 2-1.
The state of development and experience with these modes of remediation are quite varied. The containment of contaminated sediments in place has been applied on a full or demonstration scale at a few locations, including the Sheboygan River and Waukegan Harbor Superfund sites on the Great Lakes. To date, the treatment of sediments in place has been demonstrated in the Great Lakes on a limited scale with a few technologies, but the results of these demonstrations are not yet available.
The containment of contaminated sediments dredged from navigation projects has been practiced for many years, and a significant amount of engineering and design information and guidance is available on this mode (Saucier et al. 1978; USACE 1980c, 1987b). The treatment of excavated sediments has been demonstrated on a pilot scale at a number of locations (including several ARCS AOCs) and implemented on a full scale at only one site on the Great Lakes. Much of the engineering and design information about treatment technologies for contaminated sediments has come from applications with materials other than sediments (e.g., soils, sludges).
The evaluator should begin the screening process by considering the four modes of sediment remediation listed in Table 2-1 in light of the objectives and scope of the project. It is possible that one or more of these modes might be eliminated categorically by the project objectives or scope. For example, if the project area is a navigation channel, and must be maintained at some depth for recreational or commercial navigation, in-place (non-removal) options might be eliminated from further consideration. In some cases, the project objectives may require treatment of a specific contaminant. This would eliminate containment options (alone) from further consideration.
For the remaining modes of sediment remediation, the evaluator should next consider the technology types available for the critical components. In-place remediation is considered a single-component alternative. It is expected that the critical component of a remedial alternative involving sediment removal will either be the treatment or disposal component. In most remediation projects involving dredging, one or both of these components will largely determine if the alternative is ultimately feasible.
The evaluator should screen technology types for the critical components based on criteria developed by or with the project proponent. The criteria for screening remedial alternatives under Superfund are defined (USEPA 1988a) as:
- Overall protection of human health and the environment
- Compliance with applicable and relevant regulations
- Long-term effectiveness and permanence
- Short-term effectiveness
- Reductions in toxicity, mobility, and/or volume of contaminants
- State and community acceptance
These criteria are appropriate for an RI/FS investigation, but require more detailed information than necessary for the screening level in the sediment remediation framework described herein. A shortened list of screening criteria for this framework might include:
- State of development and availability
- Compatibility with sediments and contaminants
The initial screening of remediation technologies is conducted using readily available information on technologies and project-specific information on sediment conditions. No new data are collected. It is generally not necessary to identify specific process options at this point. If more than one remediation technology provides the same results, it may be possible to eliminate those technologies whose costs are greater by an order of magnitude (Cullinane et al. 1986a). After potential technology types for critical components have been evaluated based on the project-specific criteria, other components needed for each complete remedial alternative need only be identified to the extent necessary to determine the overall implementability and cost. Because of the importance of this initial screening step, and because the level of information on technologies varies greatly, screening should be conducted by persons experienced in such evaluations. This guidance document and the literature review of removal, containment, and treatment technologies prepared for the ARCS Program (Averett et al. 1990 and in prep.) may be used as primary sources for this effort.
At the conclusion of the screening step, the evaluator should have identified a limited number of technology types for the critical components of each remedial alternative. With the wide diversity of sediment remediation approaches available, it is recommended that at least one alternative be considered in the next step (preliminary design) for each of the remediation modes determined to be consistent with the project objectives and scope. For a majority of cases, at least one nonremoval technology, one confined disposal option, and one or more treatment technologies should be considered.
The next step in the decision-making framework (Figure 2-4) is the development of preliminary designs for those technologies that have passed the screening-level evaluation. This step involves the design of a limited number of remedial alternatives in sufficient detail to make a selection for implementation. Some additional data on the sediments, technologies, and locations for implementation may be collected during this step.
The preliminary design is a complex process that involves many separate decisions. A remedial alternative may include a number of components, and the preliminary design process must ensure that the process option selected for each component is technically feasible, compatible with other components, and capable of meeting applicable environmental regulations and project-specific constraints.
The following aspects of a sediment remedial alternative and the preliminary design analysis are discussed briefly below:
- Material characteristics
- Materials handling
- Compatibility of components/technologies
- How to begin the design phase
- Information requirements
Material Characteristics--Sediments are soil and water mixtures transported by and deposited in aquatic environments. In most cases, the relative amounts of gravel, sand, silt, clay, and organic matter in a sediment reflect the particle size characteristics of the soil in the watershed and the sorting that occurred during transport. In a limited number of waterways, sediment physical characteristics are more influenced by the nature of the anthropogenic discharges to the system. Chemical contaminants in the sediments represent only a small portion of its mass and do not, with few exceptions, significantly alter the grain size distribution. Sediment contaminants tend to be associated more with silt and clay fractions and less with sand and gravel fractions, because fine-grained sediments, particularly those with significant organic carbon content, have a higher affinity for some contaminants. In addition, sand and gravel deposits are usually present in areas of high energy (i.e., erosion and scouring) where fine-grained sediments and contaminants have been washed away.
The physical and chemical characteristics of the sediments in a waterway are site specific and may vary both laterally and vertically. Some sediment deposits have layers with distinct physical and chemical properties. In other areas, the sediment properties may be relatively homogeneous. The distribution of contaminants in a sediment deposit may reflect activities over many years or decades. Evaluators should not expect to be able to develop contaminant distribution profiles in sediments with as high a level of resolution as for other environmental media.
Most fine-grained, contaminated sediments have been deposited in recent (geologic) time and are not well consolidated, particularly in navigation channels that have been dredged in the past. Sediments may have significant amounts of oversized materials and debris. Cobbles, gravel, coal, and other bulk commodities may have been spilled from adjacent docks or passing ships. Bottles, cans, tires, bicycles, shopping carts, and entire car bodies have been recovered in dredging operations.
The amount of water in sediments is one of its most important physical properties, but there is considerable confusion about the terminology for this property (see Glossary for definitions). This manual will refer to the solids content of a sediment and avoid using the terms moisture or water content, which have a layman definition at odds with their engineering definition.
Site-specific analysis of the physical and engineering properties of sediments should always be obtained before even the most preliminary design is begun. Recommended physical and engineering properties for analysis are shown in Table 2-2 (detailed analytical procedures are available in USACE 1970). Also shown are typical values for contaminated sediments in Great Lakes tributaries.
A general rule-of-thumb is that in-place, predominantly fine-grained, contaminated sediments have a solids content of approximately 50 percent, and that dry sediment solids generally have a density between 2.5 and 2.7 g/cm. Using these values, a unit of sediment (in place) is roughly one-third solids by volume. With this solids content, sediments are only slightly fluid, and would not readily flow. The physical properties of a sediment can be altered by components of a remedial alternative. In some cases, this is done intentionally to facilitate handling or treatment. In other cases, changes to sediment physical properties by a component may increase material quantities and greatly affect costs.
Materials Handling--Each component of a sediment remedial alternative (except nonremoval) involves a significant amount of materials handling. The removal component involves the excavation of the sediment from the bottom of the waterway. The transportation component involves moving excavated sediment to a location where the material may be placed into a holding area, moved into pretreatment units, and then carried into treatment units. In addition to the solids, there are other materials that must be handled. For example, the residual water from dewatering, effluent, and leachate systems must be collected and routed. In addition, some treatment technologies create residues other than solids and water that must be handled.
One of the most important factors that affects materials handling is how the sediments are removed. Sediments that are dredged mechanically are generally removed at or near their in situ solids content. In contrast, hydraulic dredging entrains additional water with the sediments and produces a slurry that may have a solids content ranging from 10-20 percent. In creating this slurry, the total material volume increases 3-6 times. This increase in volume affects all subsequent components of the remedial alternative. For example, the use of hydraulic dredging may eliminate certain transportation options, increase the size requirements of a disposal area, and necessitate larger and more sophisticated effluent treatment systems.
A common goal of most sediment remedial alternatives is to separate the solids from the water fraction of the sediment (i.e., dewater) to the maximum extent possible. This is done to minimize disposal costs for the solids and is a requirement of some treatment technologies. Sediments may be dewatered through a variety of processes to a solids content greater than 50 percent. Depending on the process used, there may be little or no volume reduction, because water is replaced by air in the voids between the sediment solids.
Contaminated sediments may be handled and rehandled a number of times during the implementation of a remedial alternative. The costs and contaminant losses of each of these handling operations may be significant.
Compatibility--The need for and compatibility of components and technologies is determined by a number of factors, including physical requirements, material characteristics, rate of processes, and logistical considerations.
The consideration of these factors is best illustrated by example. Assume that the critical component is treatment, and the technology type being considered is solvent extraction. Most process options of this technology have similar requirements on the feed material. Process options could be constructed that are capable of treating 100-500 tonnes per day, generating three residues: solids, water, and extracted organic compounds. These process requirements will have the following effects on other components:
- The process, even with multiple units, cannot keep pace with dredging. An area for temporary storage of sediments is necessary.
- The feed material must have a high solids content. This can be accomplished by restricting dredging to mechanical methods or using hydraulic dredging followed by one or more dewatering steps.
- The feed material must have oversized material (i.e., larger than 5 mm) removed. A pretreatment component, involving screening or other technologies, must be applied.
- The water from the treatment process and the water from sediment dewatering must be treated and discharged. Different water treatment technologies may be needed for these residues, depending on the nature and concentrations of contaminants present.
- Disposal methods must be identified for the solid and organic residues. Additional treatment may be required for one or both of these residues prior to disposal.
As illustrated above, the development of a sediment remedial alternative begins by describing a single component and identifying its requirements and limitations. The other components can then be identified and technology types can be considered and evaluated for compatibility. There is no particular sequence for evaluating components. In most cases, they must be considered concurrently.
How to Begin the Design Phase--Although subsequent chapters in this document discuss remediation components in a logical process sequence (i.e., removal is followed by transport, which is followed by pretreatment, etc.), the formulation of an overall remedial alternative is not as simple as following this linear sequence to select the optimal technology for individual components. The preliminary design phase usually begins with the disposal component because it represents the terminal point of two components (removal and transport) and the disposal facility location may be used to implement other components (pretreatment, treatment, and residue treatment). Most treatment technologies will require a disposal facility and some form of pretreatment to support the treatment process. The disposal facility (or a secure land area) is needed for storing, pretreatment, and handling of dredged sediments; as a base for treatment operations; and possibly for long-term disposal of residues. While it is possible to perform these functions at different sites, there would be increased difficulties associated with obtaining lands for managing contaminated materials.
The availability and location of lands for handling or disposing of sediments can often influence the selection of remediation technologies. For example, if the only available lands for a disposal site are several kilometers from the removal site, hydraulic dredging and pipeline transport technologies may not be feasible. Some technologies, such as confined disposal, gravity dewatering, and land application of sediments, require a great deal of land. In contrast, most technologies that rely on process equipment (e.g., mechanical dewatering, solvent extraction, thermal treatment) are relatively compact and have smaller land requirements.
Selection of disposal and/or treatment sites for contaminated sediments may be the most controversial and time-consuming decision of the entire project. In fact, the public and agency acceptability of a project may be determined largely by this decision. In areas adjacent to urban waterways, land is a limited resource. It is therefore recommended that preliminary design begin with the identification of suitable lands. A technically feasible alternative without a site for implementation is of limited value.
Information Requirements--Specific types of information are required to prepare a preliminary design, evaluate its feasibility, and develop estimates of project costs and contaminant losses. A list of the most basic information required to initiate an evaluation of sediment remedial alternatives is provided in Table 2-3. Potential sources of historical information are also provided.
Additional information needed to evaluate the feasibility of specific technologies and estimate their costs and contaminant losses is discussed in subsequent chapters on each technology type. To obtain this information may require analysis of the physical and engineering properties of sediments, bench- or pilot-scale evaluations of treatment and/or pretreatment technologies, laboratory tests to determine contaminant losses, laboratory tests that simulate dewatering and residue treatment, and surveys and geotechnical explorations of lands to be used. Some of these data collection activities may be postponed until the detailed design phase of the project. Best professional judgment must be exercised in making this decision.
Ideally, more than one remedial alternative will be identified that is feasible and meets the project objectives. In this case, the project proponent must decide which alternative to recommend and support. The implementation of the selected remedial alternative may involve a number of activities, including:
- Securing funding
- Development of detailed design, plans, and specifications
- Acquiring real estate and rights-of-way
- Obtaining appropriate permits
- Contract advertisement, negotiation, and award
- Construction, operation, and maintenance
These activities are discussed briefly below.
Funding--While discussion of the sources and methods for securing funding for implementation is beyond the scope of this guidance document, a few consequences of the timing of funding are worth mentioning. For large remediation projects, funding may not be available all at one time but in increments, perhaps coinciding with budgetary cycles. It may therefore be appropriate to plan the implementation of remediation in increments. The challenge is to divide the project into increments that can stand alone from environmental and engineering feasibility perspectives should the next funding increment be delayed or unavailable. For additional information on funding opportunities for RAP activities, the reader is referred to the series of Apogee Research, Inc. reports on this subject (Apogee Research, Inc. 1992a,b, 1993a,b).
Detailed Design--This step of implementation involves the detailed design of the remedial alternative and preparation of plans and specifications for construction. During this step, extensive data collection may be conducted, including pilot- or full-scale testing of process equipment, detailed surveys, and geotechnical explorations of lands to be acquired. It is not uncommon for significant changes in the project design to occur at this stage as a result of the new data collected and the application of more sophisticated design analytical methods. It is quite possible that the alternative recommended by the preliminary design/feasibility study is determined to be infeasible. By the completion of this step, virtually every aspect of the construction and operation of the remedial alternative should be designed and thoroughly reviewed to ensure the technical accuracy and engineering feasibility of the alternative.
Real Estate--The acquisition of real estate, easements, and rights-of-way for project construction and operation need to be completed before a construction contract is advertised. These acquisitions may include land for pretreatment, treatment, and disposal operations; easements for an area to mobilize dredging equipment; or a right-of-way for construction equipment and sediment transportation. Easements or rights-of-way may also have to be obtained from riparian property owners along the waterway.
Permits--Applicable permits and certifications for project construction and operation should be obtained before a construction contract is advertised. A detailed discussion of the legal and regulatory requirements for sediment remediation is provided later in this chapter.
Contracting--Contracting mechanisms and regulations are organization-specific and are beyond the scope of this guidance document. Parts of the remediation project, or the entire effort, may be contracted. Superfund remedial planning and design are often contracted separately from the remediation construction. The most common contracting approach for remediation construction is to advertise the entire remediation project as a single contract for a turn-key operation. In this case, a prime contractor would be responsible for obtaining the necessary subcontractors with the specialized equipment or experience required. An alternative approach is for the project proponent to purchase some of the equipment and contract for its operation. This approach may be advantageous if the project is large and must be conducted in a number of operational cycles, or if there are several project areas that can be remediated using the same equipment. Modifications are often required in the design and operation of a project after construction has been initiated because of changes in site conditions, changes in materials, or the failure of a component to operate as expected. These design and operational modifications should always be coordinated with the designers and with regulatory agencies.
Construction, Operation, and Maintenance--These activities are discussed in detail in Chapter 10.
Estimating Project Costs
This section discusses the development of cost estimates for sediment remedial alternatives to support the decision-making and implementation processes. There is no existing guidance on estimating costs specifically for sediment remediation projects; however, there is considerable guidance on estimating costs for general construction and some guidance for hazardous waste remediation projects. This discussion presents the cost estimating procedures used by the Corps for civil works projects and those used by the USEPA for Superfund projects. The appropriate guidance for most sediment remediation projects would include a combination of these approaches. Additional guidance for estimating the costs of specific components of sediment remedial alternatives is provided in subsequent chapters of this document.
Project cost estimates are required during all phases of a sediment remediation project, from initial planning, through detailed design, and during construction and operation. The purpose of the cost estimates will change as the project progresses. During the planning stages, cost estimates are used as a criterion for screening technologies and selecting the preferred alternative. At the detailed design stage, cost estimates are often used to compare technically equivalent features and identify those that may be suitable for value engineering (VE) studies. Following detailed design and preparation of plans and specifications, cost estimates are used to evaluate bids on project construction and operation. During construction, cost estimates are used for scheduling payments, contract negotiation, and dispute resolution.
The reliability of a cost estimate depends largely on the level of detail available at the time it is prepared. It also depends on the predictability of variables and factors used to develop the cost estimate. A thorough knowledge and understanding of the scope of work and all components associated with site remediation is necessary for the development of a reliable cost estimate, including a clear understanding of the construction operations and techniques that would be used.
Cost estimates should complement the decision path. For civil works projects, such as maintenance dredging, there are two types of cost estimates in the decision-making process: the current working estimate and the government estimate. The current working estimate is an estimate that is prepared and updated periodically during the planning and design of a project. The level of detail and reliability of this estimate reflect the current state of project evaluation and design (USACE 1980c). The current working estimate is a total project cost estimate, which includes all reasonable costs that will be required during project implementation (i.e., the estimated costs of construction and operation contracts, engineering and design efforts, construction management and real estate easements, and land acquisition). The current working estimate is used as a tool to support the decision-making process and control costs, and should be prepared with as much accuracy as possible, so that the total project cost estimate for site remediation can be relied upon at the earliest possible stage in the decision-making process.
For virtually all projects that are funded by the Federal government, and for most projects funded by other governmental agencies, a government estimate or equivalent is developed at the end of detailed design and immediately prior to the advertisement of the contract(s) for construction and operation (USACE 1982). The government estimate is used to evaluate construction contract bids, control negotiations, establish a pricing objective for procurement and contracting purposes, and serve as a guide in developing progress payment schedules. It is a detailed construction cost estimate and does not include the other noncontract items of the current working estimate. The development of a government estimate for a Federal project must follow the procedures and guidelines of the Federal Acquisition Regulation (FAR) (48 CFR Chapters 1-99).
A sediment remediation project has capital, operation, and maintenance costs. Capital costs include expenditures that are initially incurred to develop and implement a remedial action (e.g., dredging and transportation, construction and operation of a treatment system, construction of a disposal facility) and major capital expenditures anticipated in future years (e.g., capping a confined disposal facility [CDF] or decontamination of treatment equipment) (Burgher et al. 1987). The following elements should be considered in developing estimates of capital costs (Cullinane et al. 1986a; Burgher et al. 1987):
- Relocation costs
- Costs of lands, easements, and rights-of-way
- Land and site development costs
- Costs for buildings and services
- Equipment costs
- Replacement costs
- Disposal costs
- Engineering expenses
- Construction expenses
- Legal fees, licenses, and permits
- Contingency allowances
- Startup and shakedown costs
- Costs of health and safety requirements during construction
Operation and maintenance are post-construction activities needed to ensure the effectiveness of a remedial action (Burgher et al. 1987). These activities might include treatment plant operations, surface water and leachate management at a disposal facility, and monitoring and routine maintenance at disposal sites. The following elements should be considered in developing estimates of operation and maintenance costs (Cullinane et al. 1986a; Burgher et al. 1987):
- Operating labor costs
- Maintenance materials and labor costs
- Costs of auxiliary materials and energy
- Purchased service costs
- Administrative costs
- Insurance, taxes, and licensing costs
- Maintenance reserve and contingency fund
The capital, operation, and maintenance cost data needed for preparing estimates are divided into two categories, direct costs and indirect costs. The direct costs are those that are directly attributable to a unit of work. They are generally referred to as labor, equipment, and material/supply costs. The labor rate, equipment rate, and material/supply quotes are readily available from many sources, some of which are discussed in later chapters. However, production rates, hours of work, size of crew, selection of equipment and treatment plants, and schedules are estimated largely from site-specific data.
There are some differences between the civil works and Superfund guidance for estimating indirect costs. The Corps approach considers indirect costs, sometimes referred to as distributed costs, to include all costs that are not directly attributable to a unit of work, but are required for the project. These costs might include field office and home office operations, permits, and insurance. The USEPA guidance for hazardous waste remediation (Burgher et al. 1987) includes these costs, plus engineering expenses, startup/shakedown costs, and contingency allowances, as indirect costs. Indirect costs are typically estimated as a fixed percentage of the total direct costs.
For preliminary cost estimates, indirect costs (as defined by the Corps) may be estimated as 10-15 percent of direct costs. The USEPA guidance (Burgher et al. 1987) offers the following numbers for estimating specific indirect costs:
- Engineering expenses (7-15 percent of direct capital costs)
- Legal fees, licenses, and permits (1-5 percent of total project costs)
- Startup and shakedown costs (5-20 percent of capital costs)
- Contingency allowances (15-25 percent of total capital costs)
When screening-level construction cost estimates are prepared, there are generally few details available that would warrant a detailed analysis of direct and indirect costs; total unit price data are often used instead. However, when a detailed construction cost estimate is required in the later stages of design and implementation, direct and indirect cost data are estimated separately.
The level of confidence of a cost estimate depends on the level of detail available at the time it is prepared. One method to improve the confidence in the cost estimate is to assess and include appropriate contingencies in the estimate. A contingency is a form of allowance to cover unknowns, uncertainties, and/or unanticipated conditions that are not possible to adequately evaluate from the available data. Computer software, such as HAZRISK (Diekmann 1993) and REP/PC (Decision Sciences Corp. 1992), is available to perform a more formal assessment and assign contingencies. If these programs are not available, the contingency rates shown in Table 2-4 may be used instead. These rates are empirical and are only a guide. USEPA contingency allowances for feasibility studies (between 15 and 25 percent of capital costs) are in general agreement with the numbers shown in Table 2-4.
Cost estimates are one of the criteria used to screen remediation technologies for further consideration. The screening cost analysis for an RI/FS investigation involves order-of-magnitude costs to eliminate alternatives with costs that are 10 times or higher than costs for other alternatives (Burgher et al. 1987). The accuracy of costs at the screening level for RI/FS investigations should be between +100 and -50 percent (Burgher et al. 1987).
At the screening level, the project cost analysis is very crude and limited to available information on the sediments, site conditions, and technologies being considered. Because the level of detail is minimal at this phase, historical data and parameters of similar past projects are recommended for the development of the cost estimate. Substantial amounts of historical cost data for some components of sediment remediation (i.e., removal, transport, disposal, and residue management) are available and are summarized in later chapters of this document. The USEPA has developed a Remedial Action Cost Compendium (Yang et al. 1987) that shows the range of actual costs at Superfund projects.
Historical cost data on the pretreatment and treatment components are very limited, and in some cases the only data available are projections made by technology vendors based on bench- or pilot-scale applications. Cost projections for technologies that do not already have full-scale equipment with some operating history should be approached with a certain amount of skepticism. One of the major factors in the cost of many innovative treatment technologies is the investment required for the development, scaleup, construction, and testing of full-scale equipment. The amortization of these development costs greatly affects their unit costs and the degree of uncertainty associated with those costs. Very few remediation projects are able to bear these development costs alone, and few companies are willing to make this investment unless there is a clear indication that there will be a dependable market for the technology at several remediation sites. One potential solution to this handicap is for interests from several AOCs having similar sediment contamination problems to join forces in financing the development or acquisition of a remediation technology.
During the preliminary design phase, a limited number of remedial alternatives are evaluated in sufficient detail to make a selection for implementation. This phase is comparable to the feasibility study for Superfund projects. The preliminary design should contain sufficient engineering and design information that could readily lead into the next phase (the detailed design). The cost estimate should be prepared based on the latest information available and should include all reasonable costs required in the implementation phase. The estimate should incorporate costs for additional engineering and design, real estate easements and land acquisition, and construction costs. This cost estimate will serve as a baseline current working estimate for project management through the implementation phase.
The process for evaluating costs during a Superfund feasibility study includes the following steps (Burgher et al. 1987):
- Estimation of costs
- Present worth analysis
- Sensitivity analysis
- Input to alternatives analysis
The accuracy of cost estimates for feasibility studies for Superfund projects should be within the range of +50 to -30 percent (Burgher et al. 1987).
This phase should include preparation of a detailed design and the plans and specifications for contracting the construction and operation of the remedial alternative. During the detailed design, cost estimates can be used to compare technically equivalent features in a process known as VE. VE is directed at analyzing the function of construction, equipment, and supplies for the purpose of achieving these functions at reduced life-cycle cost without sacrificing quality, aesthetics, or operations and maintenance capability (USACE 1987f).
During the development of plans and specifications, a detailed government estimate is prepared. This government estimate is used to evaluate bids on project construction and operation contracts. Bids are evaluated for balance as well as dollar amount. Corps regulations for civil works projects will not allow a contract award if the low bid exceeds the government estimate by more than 25 percent. During construction, cost estimates are used for scheduling payments, contract negotiations, and dispute resolution.
The accuracy of a cost estimate depends on the reliability of the information used in its development. For some of the components of a sediment remedial alternative there are a large number of sources of cost data available. A list of a few sources that could be consulted for cost estimates is shown in Table 2-5.
Construction costs may vary significantly from one region of the country to another. To convert approximate costs, area adjustment factors may be applied. Some Federal agencies, such as the U.S. Departments of Labor and Energy, maintain regional cost information. The Corps maintains a Civil Works Construction Cost Index System (CWCCIS), which may be used as a guide for regional construction cost adjustments.
Several computer software programs have been developed for cost estimating and are in general use. The Corps has developed a Micro-Computer Aided Cost Engineering System (MCACES) that is being used worldwide for construction cost engineering. This software is available commercially from Building Systems Design (1992). The U.S. Department of Energy has developed a summary of available cost estimating software applicable to environmental remediation projects (Youngblood and Booth 1992), and the reader is referred to this document for more information on how to obtain these software packages. Software has been developed by or for the USEPA (CORA and RACES), the U.S. Air Force (ENVEST and RACER), and the U.S. Department of Energy (FAST, MEPAS, and RAAS). If computer software is not available, manual estimating techniques are readily available (USACE 1980c, 1982).
Cost information provided on sediment remediation technologies in this document has been adjusted to January 1993 price levels using the indices in the Engineering News Record (ENR).
Estimating Contaminant Losses
No remedial alternative for contaminated sediments is without some environmental consequence. The balancing of environmental benefit vs. cost is a critical part of the evaluation of sediment remedial alternatives. Ideally, the alternative that maximizes this benefit:cost relationship would be selected. However, the costs, as well as social, legal, and political considerations, all have important roles in the final decision.
Environmental damages and benefits are not easy to quantify in measures that are readily comparable. Risk assessment is one of the methods to quantify the environmental effects of a project or condition. Risk assessment procedures determine the potential harm caused by exposing humans or other organisms to contaminants. Contaminant exposures may be measured directly or predicted using mathematical models, and may occur through various media (e.g., air, water, solids, biota) and exposure routes (e.g., inhalation, ingestion, dermal contact). A detailed discussion of risk assessment and modeling in relation to contaminated sediment remediation is provided in the ARCS Risk Assessment and Modeling Overview Document (USEPA 1993a).
To evaluate risks to human health or the environment, the exposure conditions must be fully characterized. To use mathematical models to predict the exposure conditions, the loadings of contaminants must be estimated and used as input to the model(s). The losses of contaminants from sediment remedial alternatives may be estimated through a number of techniques that were evaluated by the ARCS Program.
Contaminant loss is the movement or release of a contaminant from a remediation component into an uncontrolled environment. Examples of loss include spillage or leakage during dredging and transport, seepage from a capped in situ site or from a CDF, and residual contamination in the treated discharges from a disposal facility or sediment treatment unit. Contaminants that remain within a controlled area or process stream, or are modified or destroyed by a process, are not considered losses. The term loss is reserved for the uncontrollable or unintentional discharge of contaminants.
Contaminant loss can occur during each component of a sediment remedial alternative through one or more pathways. For example, the potential pathways for contaminant loss from a CDF include surface runoff, effluent, seepage, leachate, volatilization, dust, and uptake by plants and animals (Figure 2-6). The contaminant loss from a component is the sum of the individual losses through the various pathways, and the contaminant loss from a remedial alternative is the sum of the losses from each component.
The magnitude of contaminant loss may vary greatly between remedial components and pathways and is influenced by the type of contaminant being considered. The losses through one pathway may be thousands or hundreds of thousands of times greater than the losses through other pathways in the same component. The losses through some pathways or from some components may be considered insignificant for specific evaluations. As a result, it is worthwhile to assess the relative importance of different pathways of contaminant loss before proceeding with detailed estimates. The contaminant losses discussed in this document are not meant to be the final determinant in the complete environmental efficacy of a particular sediment remedial alternative, however. The losses are intended to be used as loadings in the implementation of a contaminant fate model as described in the ARCS Risk Assessment and Modeling Overview Document (USEPA 1993a).
A detailed investigation of contaminant losses from sediment remediation components was conducted for the ARCS Program (Myers et al., in prep.). This study identified contaminant migration pathways, examined existing predictive techniques for estimating contaminant losses, and evaluated their applicability and reliability. This study (Myers et al., in prep.) should be used as the primary reference for developing contaminant loss estimates for sediment remedial alternatives. Key points from this study are summarized below.
Predictive techniques for estimating contaminant losses generally fall into one of two categories: a priori techniques and techniques based on pathway-specific laboratory testing. A priori techniques are suitable for planning-level assessments. Techniques that use pathway-specific test data provide state-of-the-art loss estimates.
The state of development of predictive techniques for estimating contaminant losses from remediation components varies with the component and the loss pathways. For some remediation components there are no pathway-specific tests available. In these cases, a priori techniques may be the only techniques available; however, a priori techniques are not always available for all pathways of all components.
The confidence and accuracy of the contaminant loss estimates depend on the state of development and the amount of field verification data available. In some cases, there may be a substantial amount of field data available, but predictive techniques are not designed to produce data that are directly comparable to field data. In this case, confidence is low and accuracy is unknown. For the prediction of contaminant losses during dredging, field data on turbidity and suspended solids downstream of dredging operations may be available; however, predictive techniques are used to estimate contaminant flux in the water column at the point of dredging. In some cases, predictive techniques (e.g., prediction of leachate losses) have a sound theoretical basis, but few field verification data exist. In this case, confidence is high and accuracy is unknown.
Losses During Dredging
Predictive techniques for sediment losses during hydraulic and mechanical dredging are available for conventional dredging equipment. Predictive techniques are not available for innovative dredging equipment options. The available predictive techniques provide estimates of sediment losses in terms of mass loss per time at the point of dredging. Exposure concentrations are not estimated. To estimate exposure concentrations, the predicted fluxes of sediments and the associated chemical contaminants must be incorporated into water quality or exposure assessment models. Techniques for estimating contaminant losses during dredging are still in the early development stage. Techniques have been proposed, but field validation data are scarce. The available techniques are inherently a priori, although laboratory tests have been considered. Efforts are ongoing in the Great Lakes to develop predictive techniques for estimating contaminant losses during dredging, at the point of dredging. As previously discussed, confidence is low for the prediction of losses during dredging, and accuracy is unknown.
Losses During Transportation
Techniques for estimating losses of sediments and the associated chemical contaminants during the transportation of dredged material are not available for most transportation modes. Pipeline breaks, scow spillage, and truck accidents can be expected to occur, but the frequency of such occurrences associated with dredged material transportation has not been documented, and there has been little effort to quantify the associated losses. Predictive techniques for losses from scows due to volatilization of contaminants are available, but have not been field verified.
Losses During Treatment
The limited database for treatment of contaminated sediments and the strong influence of sediment characteristics on treatability preclude the use of a priori loss estimates for most treatment technologies. Laboratory techniques are available for estimating losses for most treatment technologies. Most treatment technologies will generate waste streams that, unless decontaminated, constitute a loss pathway. Even destruction technologies will have some estimable loss because no treatment process is perfect. Treatment process losses can be in the form of contaminated solid residuals requiring disposal (with attendant losses) or in the form of contaminated fluids. Fluid losses include gaseous emissions, discharged process wastewater, and other liquid releases.
Predictive techniques for contaminant losses during treatment are based on a materials balance of the process treatment train. A process flow chart should identify waste streams through which contaminants can escape treatment or control. However, detailed information is not usually available until after treatability studies have been completed. The technical basis for using data from treatability studies to estimate contaminant losses is well developed, but there are few verification data for full-scale dredged material treatment processes.
Loss estimates based on treatability studies are anticipated to be reliable and accurate. A high degree of confidence is expected for those treatability studies with good materials balance. If the materials balance is poor, then confidence will be low.
Losses During Disposal
Predictive techniques are available for most of the key pathways by which contaminants are lost from CDFs and confined aquatic disposal sites. Predictive techniques vary in their stage of development, depending on the disposal alternative and pathway. A priori techniques are available for estimating losses from confined aquatic disposal sites; however, there are few field verification data for these techniques. A priori and test-based techniques for estimating effluent losses during hydraulic filling of confined disposal sites are well developed, but techniques for estimating losses during mechanical disposal at in-water and nearshore CDFs are more crude and have only been conducted at a few sites (USACE Chicago District 1986).
Scientifically sound a priori and test-based techniques are available for estimating losses from CDFs by leaching. Predictive techniques for leachate loss have not been field verified. Well-developed, test-based techniques are available for estimating runoff losses at CDFs, but there are no a priori predictive techniques available for runoff. The only predictive techniques available for estimating volatile losses from CDFs are a priori techniques. Estimation techniques for volatile losses from dredged material are available, but have not been field verified.
Confidence and accuracy for a priori loss estimates from CDFs and confined aquatic disposal sites are low. Confidence and accuracy for test-based loss estimates vary with the stage of development of the test and interpretation procedures. Confidence and accuracy are high for estimating effluent loss during hydraulic filling of CDFs. Confidence is high for test-based estimates of leachate losses, but accuracy is unknown. Confidence and accuracy are high for estimation of test-based runoff loss.
Level of Effort Required
A priori techniques require less effort than the test-based techniques for estimating contaminant losses. The computational frameworks for both types of techniques are similar so that computations performed using a priori techniques usually do not have to be reconstructed for the test-based techniques. The major difference in effort is the time and money required for test-based loss estimates. A priori loss estimates can be used to guide resource allocation for pathway- and remediation component-specific testing.
Most a priori techniques can be implemented using spreadsheet software for desktop computers. Some aspects of leachate loss estimation require running the Hydrologic Evaluation of Landfill Performance (HELP) computer model (Schroeder et al. 1984). This model runs on desktop computers and is required for both a priori and test-based estimates of leachate losses. Obtaining appropriate coefficients for the a priori equations can be a significant effort. A standardized default database for model coefficients is not currently available.
Test-based predictive techniques require substantial time and money if a full suite of tests are conducted. Resource requirements are relatively small for some key pathways such as effluent losses. Other pathways, such as runoff losses, currently require a large volume of sediments and the tests take several months to complete.
Type of Data Required
The minimum data required for most a priori techniques are bulk sediment chemistry and project-specific design information. The project-specific design information needs are numerous, but this information is usually available at the preliminary design phase. For CDFs, for example, a dredging schedule, dredge production rates, site geometry, foundation conditions, dike design, disposal mode (hydraulic or mechanical), and other similar types of information are needed.
For remedial alternatives involving treatment, data from bench- or pilot-scale treatability studies are needed. If sediment-specific treatability data are not available, the data for a similar sediment and treatment process can be used. Pilot-scale data should be considered, if available. Information on anticipated processing rates and pretreatment and/or storage facility designs will also be needed.
Protocols for pathway-specific tests identify data requirements. A complete program for estimating contaminant losses for an array of alternatives and components should be carefully planned and coordinated to reduce replication of effort and ensure comparability among the various pathways evaluated.
Regulatory and Legal Considerations
When conducting a sediment remediation project, it may be necessary to obtain various permits or certifications as required by existing environmental laws and regulations, from appropriate Federal, State, or local agencies. For example, permits may be required for specific remedial activities or for discharges that may result from these activities. A summary of activities and discharges that may require a permit or other form of authorization under Federal law are listed in Table 2-6.
The discussion that follows focuses on Federal environmental regulations. For some of these regulations, the permitting and enforcement authority has been transferred or delegated to the State. In addition, many states have other laws and regulations that may be applicable to one or more sediment remediation activities. The regulations discussed herein and listed in Table 2-6 are not all inclusive, and the proponent of a sediment remediation project should ensure that the requirements of all applicable Federal, State, and local laws and regulations are addressed.
Any structure or work that affects the course, capacity, or condition of a navigable water of the United States must be permitted under section 10 of the Rivers and Harbors Act of 1899 (33 U.S.C. 403). This permit program is managed by the Corps, and the regulations addressing this program are contained in 33 CFR Parts 320-330 (Regulatory Programs of the Corps of Engineers). Activities associated with a particular sediment remedial alternative that would likely require a section 10 permit include the placement of an in situ cap on contaminated sediments in a waterway, dredging activities, the mooring of vessels, and the construction of any structure in the waterway. Permits issued under the authority of section 10 of the Rivers and Harbors Act of 1899 and section 404 of the Clean Water Act (see below) are typically handled concurrently by Corps district offices. The Corps coordinates section 10 permits with the U.S. Coast Guard, which issues a notice to navigation of when and where the construction activities will take place.
Any development activities in an approved State coastal zone must be consistent to the maximum extent practicable with the State plan developed under the Coastal Zone Management Act of 1972 (16 U.S.C. section 1455b et. seq.). Federal funds for Coastal Zone Management (CZM) plan development are administered by the National Oceanic and Atmospheric Administration (NOAA). Activities associated with a sediment remediation project likely to require a CZM consistency determination by the State include dredging, in situ capping, and construction and operation in the coastal zone of facilities for sediment rehandling, treatment, and disposal. Four Great Lakes states (Michigan, New York, Pennsylvania, and Wisconsin) have approved CZM plans.
The disposal of dredged or fill materials to waters of the United States is regulated under the Clean Water Act (33 U.S.C. section 1251 et. seq.). Clean Water Act section 404 in particular designates the Corps as the lead Federal agency in the regulation of dredged and fill discharges, using guidelines developed by the USEPA in conjunction with the Corps. Regulations addressing this permit program are again contained in 33 CFR Parts 320-330 (Regulatory Programs of the Corps of Engineers). Activities associated with a particular sediment remedial alternative that would likely require a permit under Clean Water Act section 404 authority include the placement of an in situ cap on contaminated sediments in a waterway or wetland, the discharge of any dredged sediments or treatment residues into a waterway or wetland, and the discharge of effluent, runoff, or leachate from a disposal facility for sediments.
As noted above, Clean Water Act section 404 permits for the disposal of dredged or fill materials into waters of the United States are issued through Corps district offices. Some nationwide and regional permits have been issued to cover specific types of discharges. Only one state (Michigan) has been delegated Clean Water Act section 404 permitting responsibilities as provided under Clean Water Act section 404(g). Permit applicants must provide sufficient information for the permitting office to complete an evaluation of the discharge under the authority of section 404(b)(1) of the Clean Water Act. The Clean Water Act section 404(b)(1) evaluation considers the overall impacts of the proposed discharge, including ecological, social, and economic effects.
Finally, Clean Water Act section 401 authorizes states to issue a water-quality certification for proposed dredged and fill disposal activities. Issuance of this certification indicates that the proposed dredged or fill disposal will not violate State water quality standards, after allowance for dilution and dispersion of contaminants. A dredged or fill discharge section 404 permit may not be processed without a Clean Water Act section 401 certification or waiver.
Water discharges resulting from a sediment remedial alternative may be regulated under various sections of the Clean Water Act. The administration of regulations developed pursuant to the Clean Water Act is the responsibility of the USEPA, the Corps, or the State, depending on the applicable section of the act.
Clean Water Act section 307 directed the USEPA to develop pretreatment standards for industries. The National Pretreatment Program was subsequently established to ensure that major industrial and commercial users of municipal sewer systems pretreat their discharges so that the discharges from publicly owned treatment works remain in compliance with their discharge permits. Technology-based standards were developed by the USEPA (40 CFR 403) to be implemented at municipal publicly owned treatment works.
The responsibility for the administration of the pretreatment program has been delegated by the USEPA to four of the Great Lakes states (Michigan, Minnesota, Ohio, and Wisconsin). Local municipalities and sanitary districts are responsible for the management of pretreatment programs for their wastewater systems and must issue pretreatment permits to significant users. One activity associated with a sediment remedial alternative that could require a pretreatment permit would be a discharge of water from a sediment disposal facility or treatment system into a municipal wastewater treatment facility through a sanitary sewer.
Clean Water Act section section 404 and 401 apply to the discharge of effluent, runoff, or leachate from a disposal facility for sediments. These regulations were discussed above.
Clean Water Act section 402 is the National Pollutant Discharge Elimination System (NPDES). This is the principal program for the regulation of point-source discharges of pollutants and is managed by the USEPA. The responsibility for NPDES permitting has been delegated by the USEPA to all of the Great Lakes states (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin). Activities associated with a sediment remedial alternative that would likely require an NPDES permit include a continuous point-source discharge of water from a sediment treatment system and the storm water discharge from a sediment disposal or treatment site. As discussed above, the discharge of water from a dredged material disposal facility is regulated under Clean Water Act section section 404 and 401. The USEPA Region 5 has stated that a point-source discharge of leachate from a CDF should be regulated under the NPDES program.
Storm water discharges from disposal and treatment sites during initial construction would also be regulated under the NPDES program. Most states have general permits that may cover these construction activities. The storm water runoff inside an operating CDF or treatment site would most likely have to be captured, routed, and treated before discharge. This runoff might be combined with other water discharges from pretreatment and treatment processes or effluent or leachate collection. In this case, the storm water discharge would be regulated as part of these other discharges under the NPDES program or section section 404 or 401 of the Clean Water Act.
The Resource Conservation and Recovery Act (RCRA; 42 U.S.C. section 6901 et. seq.) broadly defines solid waste as:
. . . any garbage, refuse, sludge from a waste treatment plant, water supply plant or air pollution control facility and other discarded material, including solid, liquid, semisolid, or contained gaseous material resulting from industrial, commercial, mining, and agricultural operations, and from community activities, but does not include solid or dissolved material in domestic sewage, or solid or dissolved materials in irrigation return flows or industrial discharges which are point sources subject to permits under section 402 of the Federal Water Pollution Control Act, or source, special nuclear, or byproduct material as defined by the Atomic Energy Act of 1954, as amended.
Subtitle D of RCRA authorizes states to issue solid waste disposal permits. As illustrated above, the RCRA definition of solid waste is very general, and few states have regulations that specifically identify sediments or dredged material as a category or class of solid waste. The Corps has a policy that dredged material is not a solid waste and is not subject to solid waste regulations. However, some Federal and State agencies do not concur with this policy. As a result, the application of solid waste regulations to contaminated sediments is still open to question.
A technical framework for designing disposal facilities for dredged material has been developed jointly by the Corps and USEPA and is discussed in Chapter 8 (USACE/USEPA 1992). This framework identifies potential pathways for contaminant loss and migration and uses testing procedures developed specifically for sediments to evaluate the contaminant losses or impacts through these pathways. Environmental controls, such as barriers, caps/covers, and leachate collection systems are used only when sediment-specific testing and site-specific evaluation demonstrate a need. This strategy is quite different from the minimum technology approach that is used under RCRA and most State solid waste regulations. The minimum facility requirements for solid waste disposal identified in RCRA (40 CFR 257-258) were structured for municipal solid waste. These requirements include a minimum design for liners, caps, and leachate collection. They also include restrictions on disposal of liquids in landfills that may be difficult to apply directly to dredged sediments containing substantial amounts of water.
Because of the uncertainty about the applicability of State solid waste regulations to contaminated sediments, most disposal site designs will reflect a compromise between a sediment-specific design and the design dictated by a State's municipal solid waste requirements.
RCRA and the Toxic Substances Control Act (TSCA; 15 U.S.C section 2601 et. seq.) provide for the regulation of materials that are classified as hazardous and toxic, respectively. Regulations developed pursuant to RCRA address the storage, treatment, and disposal of hazardous wastes (40 CFR 260-270). The USEPA is responsible for the administration of RCRA and has established three lists of hazardous wastes under Subtitle C. If a waste is not listed as hazardous, it may still be covered by RCRA if it exhibits one of four hazardous waste characteristics: ignitability, corrosivity, reactivity, or toxicity.
A low percentage of contaminated sediments will meet the regulatory definitions of hazardous or toxic materials. In some remediation projects, isolated areas or hot spots of sediments containing TSCA- or RCRA-regulated materials may be located and require different handling than the remainder of the less-contaminated sediments. Contaminated sediments, except for sediments and sludges from specific industrial processes, are not listed as hazardous wastes under RCRA. The USEPA policy is that sediments containing one or more listed hazardous wastes require handling as a hazardous waste. The Corps policy is that dredged material is not a solid waste and is not subject to RCRA regulations. As a result of this policy disagreement, there is some confusion about the application of RCRA regulations to contaminated sediments. The USEPA Region 5 and the Corps are currently preparing guidance for the construction of disposal facilities for contaminated sediments that will address the regulatory intent of RCRA and TSCA.
Sediment remedial activities that might require a RCRA permit include the storage, treatment, and disposal of contaminated sediments (or the residue from a pretreatment or treatment process) that are defined or characterized as hazardous under RCRA. The owner/operator of a facility that generates RCRA-hazardous materials must obtain a permit. States are delegated RCRA permitting authority by the USEPA in a piecemeal fashion as the State regulations are adopted. Some Great Lakes states do not have the authority to issue RCRA corrective actions.
RCRA and its amendments include a ban on the land disposal of specific wastes (including dioxin), requiring adequate treatment prior to land disposal. The design and operating requirements for a RCRA-hazardous landfill are defined in 40 CFR 264, Subpart N and in USEPA (1989d).
TSCA regulates the manufacture, use, distribution, handling, and disposal of a very limited number of materials defined as toxic substances. In effect, this Act regulates the disposal of only two substances, asbestos and polychlorinated biphenyls (PCBs). The latter of these is generally more relevant to contaminated sediment remediation. TSCA is applicable to any material, specifically including dredged material, that contains 50 ppm or greater PCBs. Sediment remedial activities that are regulated under TSCA include the handling, transport, treatment, and disposal of a sediment or treatment residue that contains 50 ppm or greater PCBs.
TSCA is managed by the USEPA, and this authority cannot be delegated. TSCA regulations (40 CFR 761.60) specifically identify three disposal alternatives for PCB-contaminated sediments and municipal sewage sludges: incineration, disposal in a licensed chemical waste landfill (40 CFR 761.75), or other alternatives accepted by the USEPA Regional Administrator. Some states have additional regulations addressing PCB-contaminated materials independent of TSCA.
The permitting requirements of TSCA vary with the remediation technology to be applied. Some technologies have been preapproved for treatment of PCBs, and no additional permitting may be necessary. The remediation target for treatment technologies under TSCA is to reduce the levels of PCB contamination to less than 2 ppm.
The 1970 amendments to the Clean Air Act (44 U.S.C. section 7401 et. seq.) directed the USEPA to establish National Ambient Air Quality Standards (NAAQS) that would provide safe concentrations of specific pollutants. NAAQS have been established for six pollutants: sulfur dioxide, particulate matter, ozone, carbon monoxide, nitrogen dioxide, and lead. In addition, National Emission Standards for Hazardous Pollutants (NESHAPS) have been established for seven pollutants: beryllium, mercury, vinyl chloride, asbestos, benzene, radionuclides, and arsenic. The USEPA regulations for the air program are codified in 40 CFR 52-61.
Under the 1990 amendments to the Clean Air Act, 189 hazardous air pollutants are to be regulated. Sources of these pollutants will be identified and regulations developed according to source categories. These sources will be required to use the maximum achievable control technology. Maximum achievable control technology standards for air emissions from solid waste storage and disposal facilities are to be developed in 1994.
The development of discharge regulations and permitting of point-source emissions are the states' responsibilities. States are required to develop State implementation plans, which assess the extent of air quality degradation and include plans for meeting the NAAQS in nonattainment areas (areas that are not in compliance with the standards) and for maintaining the NAAQS is areas that are in compliance. Regional plans for improving air quality in nonattainment areas are typically developed and managed by county or municipal governments, in cooperation with State regulatory agencies. However, the USEPA can enforce an approved State implementation plan. Sediment remedial activities likely to be subject to these regulations would be the point-source emissions from a pretreatment or treatment process to the atmosphere. Area emissions from disposal facilities may become regulated in the near future.
The Occupational Safety and Health Act (OSHA; 29 U.S.C. section 651 et. seq.) authorized the Secretary of Labor to set mandatory occupational safety and health standards. The secretary directed OSHA to develop these standards and administer their compliance. OSHA has established minimum safety and health requirements for general construction (29 CFR 1926). The Corps has developed a Safety and Health Requirements Manual (USACE 1987e), which is used to assure that Corps personnel and contractors maintain compliance with OSHA regulations. These include requirements for personnel training, medical surveillance, allowable exposure limits, and personal protective equipment (PPE).
Section 126 of SARA directed that standards be developed to protect the health and safety of workers engaged in Superfund remediation activities. OSHA standards for hazard communication, set forth in 29 CFR 1910.1200, require employers to provide information to workers exposed to hazardous chemicals. This information consists of lists of all hazardous chemicals at the site (workplace) and material safety data sheets. Workers at sites with hazardous wastes are also required to be trained to recognize the health effects, proper handling, spill control, PPE, and emergency procedures.
Section 309 of the 1970 amendments to the Clean Air Act and the NEPA of 1970 (42 U.S.C. section 4321 et. seq.) require preparation of a detailed statement when a Federal action may significantly impact the quality of the human environment. One of two types of NEPA documents must be prepared for any major Federal action: an environmental assessment (EA) or an environmental impact statement (EIS). The more detailed EIS is required when significant impacts to an important resource are anticipated.
The USEPA administers the NEPA program, but the agency that has the lead in the Federal action is responsible for preparing and coordinating the NEPA document. The NEPA document is filed with the USEPA, which publishes a notice of availability in the Federal Register.
A sediment remediation project conducted by a Federal agency or with Federal funds would require NEPA compliance. In addition, the issuance of a permit under a Federal regulatory program requires NEPA compliance. The permittee is required to provide the information and data required for a NEPA document to the permitting agency, which then prepares the EA or EIS.
There are many State and local regulations that may have to be addressed as part of a sediment remediation project. These regulations include, but are not limited to:
- Zoning ordinances
- Transportation restrictions
- Riparian authorities
- Right-of-way restrictions
- Utility easements
- Water withdrawal regulations
- Floodplain/floodway construction restrictions
The applicability of these and other State and local regulations would need to be addressed on a site-specific basis.
For example, the owners of properties adjacent to a waterway may have certain riparian rights, which can impact sediment remediation activities. These may include the rights to any lands or fill constructed in the waterway, the rights to water withdrawal, and the ownership of any materials below the ordinary high water mark. The riparian doctrine, a development of English common law, is followed in most Great Lakes states. The permission of all riparian owners would be required for virtually any sediment remedial alternative.