U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division




Environmental dredging removes contaminated sediment from a water body without draining or diverting the water. Dredges remove a certain amount of water with the sediment. The sediments are usually dewatered on land, and the water is usually treated before discharge back to the water body or public treatment works. The contaminated sediment is then disposed of in a landfill or a confined disposal facility. Highly contaminated sediment may be treated, most often by stabilization, before disposal. Unlike navigational dredging, which stresses the quick removal of relatively clean sediment, environmental dredging is more precise with greater emphasis on controlling the resuspension of contaminated sediment. Environmental dredging can be accomplished using either mechanical or hydraulic devices. In the former a bucket is used to collect the sediment and deposit it in a hopper or other container. In the later the sediment is loosened with some form of cutter head and sucked into a holding tank. Mechanically dredged sediments contain about the same water content as the in place sediment. Hydraulically dredged sediments, on the other hand, are more like a thin slurry containing 10 to 20 percent solids.

For both mechanical and hydraulic dredging, a dewatering step is necessary to reduce the volume of material that needs to be taken to a treatment or disposal site. The water that is removed from the sediment generally requires treatment before it is returned to the surface water body. Because hydraulic dredging operates on the principle of transporting the contaminated sediment to the shore as a slurry, it produces a much larger volume of water requiring treatment. For quality control and safety, the water outside the working area is monitored and analyzed to ensure that contaminated sediment is not escaping.

To protect against resuspension during dredging, the contaminated sediment area can be enclosed with silt curtains that extend to the bottom. These curtains have floatation devices at the surface and anchors at the bottom to ensure they hug the sediment floor. They are best deployed in low current environments. Real time monitoring for increased turbidity is used as an early warning sign that sediment may be resuspending.

Text adapted directly from USEPA. 2004. Presenter's Manual for: Remediation of Contaminated SedimentsAdobe PDF Logo. Office of Solid Waste and Emergency Response, 58 pp.

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Adobe PDF LogoDredging and Dredged Material Management: Engineering and Design
U.S. Army Corps of Engineers. EM 1110-2-5025, 920 pp, 2015

This Engineer Manual presents a comprehensive summary of dredging equipment and dredged material placement techniques with considerations for the selection and use of various types of dredging equipment and techniques for placement. Information includes (1) short-and long-term fates of dredged material in the open-water environment and methods for quantifying each type of material; (2) contaminant pathways from open-water placement; (3) management and control methods for open-water placement; and (4) considerations for open-water site operation, monitoring, and management. Detailed guidance is given for diked placement of dredged material in confined disposal facilities. Chapter 5 outlines opportunities for beneficial use of dredged material and provides many case studies.

Adobe PDF LogoDredging in Sediments Containing Munitions and Explosives of Concern (MEC)
Welp, T., G. Follett, M. Crull, and C.E. Pollock.
ERDC/CHL TR-08-12, 241 pp, 2008

The document compiles information gained from experiences on past dredging projects involving MEC, describing the different types of dredges and dredging projects that can encounter MEC, how these dredges' operational methodologies can be affected by MEC, and methodology modifications that have been used to deal with MEC. The text addresses engineering controls to mitigate detonation hazards, underwater MEC detection and discrimination technologies, contracting, public awareness, safety requirements, and MEC separation techniques and (where available) subsequent impacts on production rates and costs.

Adobe PDF LogoEvaluating the Effectiveness of Contaminated-Sediment Dredging
Gustavson, K. et al
ES&T Volume 42, Issue 14, pp. 5034-5378

Adobe PDF LogoThe Four Rs of Environmental Dredging: Resuspension, Release, Residual, and Risk
Bridges, T.S., S. Ells, D. Hayes, D. Mount, S.C. Nadeau, M.R. Palermo, C. Patmont, and P. Schroeder.
ERDC/EL TR-08-4, 63 pp, 2008

This report summarizes the results of a workshop sponsored by the Army Corps of Engineers and U.S. EPA in April 2006 and attended by 50 experts from government, the private sector, and academia.

Adobe PDF LogoMechanical Dewatering of Navigation Sediments: Equipment, Bench-Scale Testing, and Fact Sheets
U.S. Army Corps of Engineers, ERDC TN-DOER-T7, 34 pp, 2004

A Parametric Model for Estimating Costs for Remediating Contaminated Sediment Sites Using a Dredging Method: A Budgetary & Planning Tool for Decision-Makers
Rosengard, J., J. Wallace, M. Otten, A. MacDonald, and R. Lafrenz. International Journal of Soil, Sediment and Water 3(2):#9(2010)

This paper presents a viable parametric model for assisting managers and decision-makers in developing appropriate cost estimates for the processing and disposal of dredged materials. The model can be used for planning and budgetary purposes, communicating with stakeholders, and providing guidance to senior management. This multi-variable financial model enables cost estimates for either a single site or for a portfolio of sites (while still allowing for individual site specifications) by providing cumulative costs over the overall remediation time horizon. It allows for "what if" scenarios and provides both numerical and graphical depictions of the estimates.

Adobe PDF LogoReview of Phytoreclamation and Management Approaches for Dredged Material Contaminated with Lead
U.S. Army Corps of Engineers, ERDC TN-DOER-C29, 11 pp, 2003

Adobe PDF LogoA Review of Risk-Based Approaches to the Development of Screening Criteria for Soils and Application to Beneficial Use of Dredged Material
Bailey, S.E., D.E. Averett, and P.R. Schroeder.
ERDC TN-DOER-D14, 30 pp, 2012

This technical note discusses considerations for applying criteria to beneficial use of dredged material and summarizes approaches that have been used within and outside the United States to develop risk-based screening criteria for soils. These soil criteria potentially could be used or adapted to develop screening criteria for beneficial use of dredged sediments.

Adobe PDF LogoSediment Dredging at Superfund Megasites: Assessing the Effectiveness
Committee on Sediment Dredging at Superfund Megasites, National Research Council, 316 pp, 2007

Adobe PDF LogoTechnical Guidelines for Environmental Dredging of Contaminated Sediments
Palermo, M.R., P.R. Schroeder, T.J. Estes, and N.R. Francingues.
ERDC/EL TR-08-29, 302 pp, 2008

This document supports the Contaminated Sediment Remediation Guidance for Hazardous Waste Sites (USEPA 2005) by providing detailed information regarding evaluation of environmental dredging as a remedy component. It covers initial evaluation, pertinent site conditions and sediment characteristics, environmental dredging performance standards, equipment capabilities and selection, evaluation of production, duration, and transport, methods for estimating resuspension, residuals and release, control measures, operating methods and strategies, and monitoring.

Adobe PDF LogoTechnical & Operational Guidance Series: In-Water and Riparian Management of Sediment and Dredged Material
New York Depart of Conservation, TOGS 5.1.9, 77 pp, 2004

Confined Disposal Facilities

Adobe PDF LogoDesign Guidance for Confined Disposal Facility Lateral Seepage Control
U.S. Army Corps of Engineers, ERDC TN-DOER-R7, 12 pp, 2005

Adobe PDF LogoEffects of Confined Disposal Facility and Vadose Zone Characteristics on Leachate Quality
U.S. Army Corps of Engineers, ERDC TN-DOER-C31, 15 pp, 2003

Adobe PDF LogoEvaluation of Chemical Clarification Polymers and Methods for Removal of Dissolved Metals from CDF Effluent
Bailey, Susan E., Sangchul Hwang, Michael C. Brooks, and Paul R. Schroeder
U.S. Army Corps of Engineers, ERDC TN-DOER-R10, 16 pp, 2006

Adobe PDF LogoEvaluation of Dredged Material Proposed for Disposal at Island, Nearshore, or Upland Confined Disposal Facilities — Testing Manual
U.S. Army Corps of Engineers, ERDC/EL TR-03-1, 337 pp, 2003

Adobe PDF LogoLiner Design Guidance for Confined Disposal Facility Leachate Control
U.S. Army Corps of Engineers, 25 pp, 2004

Adobe PDF LogoScreening Evaluations for Upland Confined Disposal Facility Effluent Quality
Schroeder, Paul, Trudy Estes, and Susan Bailey
U.S. Army Corps of Engineers, ERDC TN-DOER-R11, 12 pp, 2006

Geotechnical Properties

Adobe PDF LogoGeotechnical Design Considerations for Contained Aquatic Disposal
U.S. Army Corps of Engineers, ERDC TN-DOER-N5, 19 pp, 2000

Adobe PDF LogoGeotechnical Properties and Sediment Characterization for Dredged Material Models
U.S. Army Corps of Engineers, ERDC TN-DOER-N13, 14 pp, 2001

Adobe PDF LogoIn Situ Expedient Test Methods to Determine Geotechnical Properties of Dredged Materials
U.S. Army Corps of Engineers, ERDC TN-DOER-N12, 11 pp, 2001

Adobe PDF LogoPredicting Geotechnical Parameters of Fine-grained Dredged Materials Using the Slump Test Method and Index Property Correlations
U.S. Army Corps of Engineers, ERDC TN-DOER-D1, 15 pp. 2004

Adobe PDF LogoVariability in Geotechnical Properties of Sediments and Dredged Materials
U.S. Army Corps of Engineers, ERDC TN-DOER-D2, 16 pp, 2004

Re-Suspended Sediment

Adobe PDF LogoLiterature Review of Effects of Resuspended Sediments Due to Dredging Operations
Anchor Environmental CA, L.P.
Los Angeles Contaminated Sediments Task Force, 140 pp, 2003

The layout of this paper first briefly presents the types of equipment commonly used during dredging. Next, a description of the mechanisms of sediment resuspension is provided as well as a presentation of typical dredging project sediment resuspension concentrations. Next, the literature pertaining to documented physical and chemical effects to the aquatic environment caused by resuspended sediments is presented, followed by a discussion on available best management practices. Lastly, a conclusions and recommendation section describes possible future data needs for the region.

Adobe PDF LogoProtocol for the Field Measurement of Sediment Release from Dredgers: A Practical Guide to Measuring Sediment Release from Dredging Plant for Calibration and Verification of Numerical Models
Wallingford, H.R., Ltd and & Dredging Research Ltd, 83 pp, 2003

This protocol is an evolving document that will occasionally be updated as field experience is gained. Some of the techniques described here have not yet been fully evaluated. In particular, the sampling of trailer overflow using the flow-through samplers described in Section 7.2 (as opposed to simple 'bottle' samplers has not yet been clearly demonstrated to be necessary. The results of the Rotterdam experiment during which the flow-through samplers were used are still being analyzed but preliminary indications are that such samplers are required.

Adobe PDF LogoRates and Effects of Sedimentation in the Context of Dredging and Dredged Material Placement
U.S. Army Corps of Engineers, ERDC TN-DOER-E19, 12 pp, 2005

Adobe PDF LogoSedimentation: Potential Biological Effects of Dredging Operations in Estuarine and Marine Environments
U.S. Army Corps of Engineers, ERDC TN-DOER-E20, 14 pp, 2005

Adobe PDF LogoSilt Curtains as a Dredging Project Management Practice
U.S. Corps of Engineers, ERDC TN-DOER-E21, 18 pp, 2005

Case Studies

Adobe PDF LogoEngineering Performance Standards Hudson River PCBs Superfund Site Volume 5: Appendix - Case Studies of Environmental Dredging Projects
USEPA, Region 2, 146 pp, 2004

Field Study on Environmental Dredging Residuals: Ashtabula River, Volume I. Final Report
Foote, E., G. Durell, S. Williams, J. Hardin, M. Mills, R. Brenner, C. Jones, and J. Magalen.
EPA 600-R-10-126, 82 pp, 2010

Extensive monitoring studies and physical and chemical measurements were carried out prior to, during, and after dredging along a 1,100-ft study area of the Ashtabula River. In addition to estimating the volume and concentration of contaminated sediment residuals remaining after completion of dredging, field efforts focused on comparing pre- and post-dredging sediment mass and concentration characterization data to assess the PCB concentration relationship of the residual sediment to the contaminated material removed. The residuals data indicated consistent sediment and PCB mass removals greater than or equal to 95%. The data also revealed that the sediment residuals layer was composed of more highly contaminated sediments originating from higher elevations in the vertical sediment profile, rather than the lower-concentration sediments removed from immediately above the final post-dredge sediment surface.

Final Engineering Performance Standards Hudson River PCBs Superfund Site (April 2004)
USEPA, Region 2, 1370 pp. 2004

The Hudson River ROD calls for targeted environmental dredging of approximately 2.65 million cubic yards of PCB contaminated sediment from the Upper Hudson River. These five volumes develop the performance standards for dredging related resuspension, residuals, and productivity.

Adobe PDF LogoInvestigations of Controlling Factors for Air Emissions Associated with the Dredging of Indiana Harbor and Canal (IHC) and CDF Operations
Thibodeaux, L.J., K.T. Valsaraj, R. Ravikrishna, K. Fountain, and C.L. Price.
ERDC/EL TR-08-17, 142 pp, 2008

In an investigation of specific factors that control air emissions associated with the dredging of IHC sediments and related CDF operations, three primary objectives were proposed: (1) measurements of Henry's Law constants and sediment/water desorption constants for various chemicals from IHC sediments; (2) measurement of volatile emissions from IHC sediments exposed to air; and (3) the reformulation of models developed for estimating air emissions from contaminated sediments dredging and handling activities. The data produced during these investigations have been compiled into this final report.

Methods and Metrics for Evaluating Environmental Dredging at the Ashtabula River Area of Concern (AOC)
Mills, M., R. Brenner, J. Schubauer-Berigan, J. Lazorchak, and J. Meier.
EPA 600-R-16-322, 215, 2016

Environmental dredging relies on rapid mechanical removal of the contaminated sediment layer and subsequent off-site confined disposal. Environmental dredging was selected as the remedy of choice for remediation and cleanup of the Ashtabula River area of concern (AOC), a highly contaminated sediment site in northeastern Ohio. PCBs constituted the primary COC for this site, with PAHs and inorganic chemicals comprising secondary COCs. Dredging on this AOC was carried out from fall 2006 through fall 2007. The site was extensively characterized in the spring and summer of 2006 prior to dredging. A comprehensive evaluation and monitoring program was conducted by EPA during the dredging period, immediately following dredging in early 2008, and then through 2011 to assess long-term recovery. This report summarizes and interprets the results of the 6-year study to monitor pollutant fate and transport and ecosystem recovery through the use of bathymetry; sampling and chemical analysis of sediment, water, and indigenous fish; and deployment and follow-up retrieval and analysis of macrobenthos and passive samplers.

Review of Mechanical and Hydraulic Dredging at Two Sediment Remediation Sites
Wescott, J.
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy 16:90-99(2011)

This paper compares and contrasts the methods for sediment dredging at two sediment remediation projects for EPA's Great Lakes National Program Office: the West Branch of the Grand Calumet River in Hammond, IN, and the Ottawa River in Toledo, OH. The author focuses on the specific site conditions that influenced selection of each approach as well as lessons learned during construction activities at both locations. The Ottawa River sediments contained PCBs at concentrations both above and below 50 ppm.

Adobe PDF LogoSMWG Review and Analysis of Selected Sediment Dredging Projects (Revised)
Nadeau, Steven C.
The 2nd Meeting of the National Research Council Committee on Dredging Effectiveness at Superfund Megasites, June 7, 2006, Irvine, California, 129 pp, 2006

This is a PowerPoint presentation that provides detailed descriptions of approach used, equipment used, results, costs, and lessons learned on nine sites.

Adobe PDF LogoThe U.S. EPA's Great Lakes Legacy Act Ashtabula River Clean-Up
Cieniawski, Scott
USEPA, Great Lakes Program Office, 46 pp (PPT), 2008

This is a PowerPoint presentation given to the USEPA Technical Support Program's National Sediment Forum. It contains a novel treatment system for handling PCB contaminated hydraulic dredge produced sediments.

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