Wilson, David; Rudolfo, Nicholas’ Noble, Bruce; Lally, John; Hewitt, Ronald; Kim, Kay; Grover, Barry.. (2014). “Implementation of a Thin Layer Cap on Lake Superior in Marathon, Ontario” Presenation RPIC-FCS Workshop April 14-16, 2014 Ottawa
Summary:Principal discharges resulted from untreated pulp mill effluent and treated effluent from a chlor-alkali plant which operated from 1977 to 1984. Marathon Pulp and Paper filed for bankruptcy in 2009 and ceased operation. Investigations dating back to 1980 have measured elevated mercury and PCBs in Cove sediments. Sediments not toxic to benthic organisms, but affect upper trophic community including reproductive success of bottom feeding fish. Options considered included dredging and capping alternatives. Presence of higher levels of contamination at depth and risk of resuspension were concerns with dredge options. Thin layer sand cap provided ability to achieve adequate risk reduction and to provide enhanced natural recovery of the site. Prescribed remedy is placement of 15 – 20 cm layer of clean sand over defined contaminated hot spots.
What You Will Find Here:Construction p. 13; Monitoring p. 20
Hartman, E.; Kim, K.; Santiago, R.; Joyner, R.; Grahm, M.. (2014). “The use of a thin-layer cap to manage Hg and PCB Contaminated Sediments in Peninsula Harbor, Ontario, Canada..” Presentation
Keywords:Mercury, PCBs, Pulp Mill, Chlor-Alkali Plant, Capping
Summary:The slide show describes thin-layer capping for in-situ remediation of mercury and PCB contaminated sediments in Peninsula Harbor, Ontario. Engineering design, contracting, environmental mitigation measures, implementation and monitoring are covered. Descriptive photographs are included.
What You Will Find Here:Slides
Graham, M.; Hartman, E.; He, C.; Droppo, I.G. . (2013). “Examining thin layer cap behaviour in a freshwater industrial harbor.” J Soils Sediments. 13, 1515-1526
Keywords:Bottom shear stress, Critical shear stress, Dredging, Randle reef, Residuals, Thin layer capping
Summary:A 60 ha remediation area in Hamilton Harbor, Lake Ontario will involve dredging, capping, and thin-layer capping. The site is contaminated with PAHs and heavy metals. The study focused on predicting bottom shear stress that could compromise the thin-layer cap. Bottom shear stresses exceeded critical shear stresses from both weather conditions in shallow areas and from large cargo vessels. The thin cap may require larger grain sizes in some areas to prevent erosion. The overall effect on the remediation area is expected to be minimal from localized erosion events of up to 8 mm on a 16 cm thin layer cap.
What You Will Find Here:Materials and Methods p. 1517, Results p. 1520, Discussion p. 1522
Samuelsson, G. . (2013). “In situ remediation of contaminated sediment using thin-layer capping – efficiency in contaminant retention and ecological implication.” Stockholm University. Printed by US-AB, distributed by Department of Ecology, Environment and Plant Science (DEEP)
Keywords:Sediment Remediation, Benthic Resilience, Activated Carbon Amendment, Thin-Layer Capping
Summary:Boxcores were taken from Langangsfjord, Norway. Test capping materials included activated carbon, Kraft lignin, sand, hyperite, clay, plaster, and marble. Four papers were reviewed: on ecological effects of the capping materials, on reductions of contaminant flux by capping materials, on bioaccumulation reductions by capping materials, and on a field experiment in Grenlandfjords, Norway.
What You Will Find Here:Background p. 10, In situ remediation techniques Figure 1 p. 16, General findings p.17, Discussion p. 23
Algar et al. . (2013). “Processes, Assessment, and Remediation of Contaminated Sediments.” Ed. Reible, D.D. Springer. New York.
Keywords:Sediment Deposition, Enhanced Monitored Natural Recovery, Thin-Layer Placement and Stability
Summary:Engineered thin-layer placement is best for remediating moderately elevated concentrations, under quiescent conditions, and where there is minimal natural background sedimentation. A variety of placement techniques are discussed. Lessons from a few case studies are mentioned. The usefullness of SPI camera survies is highlighted.
What You Will Find Here:Sediment Deposition p. 243, Thin-Layer Placement and Stability p. 248
Gerard Cornelissen, Katja Amstaetter, Audun Hauge, Morten Schaanning, Bjørnar Beylich, Jonas S. Gunnarsson, Gijs D. Breedveld, Amy M.P. Oen, and Espen Eek. (2012). “Large-Scale Field Study on Thin-Layer Capping of Marine PCDD/Fcontaminated Sediments in Grenlandfjords, Norway: Physicochemical Effects.” Environ. Sci. Technol., 46 (21), pp 1203012037
Keywords:Remediation, Field Demonstration, Thin-Layer Placement, Monitoring
Summary:A large-scale field experiment on in situ thin-layer capping was carried out in the polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) contaminated Grenlandsfjords, Norway. The main focus of the trial was to test the effectiveness of active caps (targeted thickness of 2.5 cm) consisting of powdered activated carbon (AC) mixed into locally dredged clean clay. Nonactive caps (targed thickness of 5 cm) consisting of clay without AC as well as crushed limestone were also tested. Fields with areas of 10?000 to 40?000 m2 were established at 30 to 100 m water depth. Auxiliary shaken laboratory batch experiments showed that 2% of the applied powdered AC substantially reduced PCDD/F porewater concentrations, by >90% for tetra-, penta- and hexa-clorinated congeners to 6070% for octachlorinated ones. In-situ AC profiles revealed that the AC was mixed into the sediment to 3 to 5 cm depth in 20 months.
What You Will Find Here:Remediation (PCDD/F p. 12030), Field Demonstration p. 12031, Thin-Layer Placement p.12031, Monitoring p. 12031, p. 12033
Kay Kim, Sue-Jin An, Roger Santiago, Victoria Renner, Rupert Joyner, Anne Borgmann, Matthew Graham, and Erin Hartman. (2012). “The Use of Thin-Layer Cap to Manage Hg and PCB Contaminated Sediments in Jellicoe Cove, Peninsula Harbour, Ontario, Canada.” Environment Canada Sediment Remediation Unit Presentation
Summary:Case study of Thin-Layer Cap in Jellicoe Cove, Peninsula Harbour, Ontario, Canada. Planning, design, construction, and monitoring is discussed.
What You Will Find Here:Remediation (Hg & PCB) p. 6, Planning p. 7, Monitoring p. 13, 56, Construction p. 30,
Cornelissen, G.; Krusa, M.E.; Breedveld, G.D.; Eek, E.; Oen, A.M.P.; Arp, H.P.H.; Raymond, C.; Samuelsson, G.; Hedman, J.E.; Stokland, O.; Gunnarsson, J.S.. (2011). “Remediation of Contaminated Marine Sediments Using Thin-Layer Capping with Activated Carbon – A Field Experiment in Trondheim Harbor, Norway.” Environ. Sci. Technol. 45, 6110-6116
Keywords:Thin-Layer Caps, Activated Carbon, PAHs, Norway
Summary:Thin-layer caps of activated carbon (AC) mixed with clay, AC alone, and AC with a sand covering were domonstrated in Norway as a remediation strategy for PAH contaminated marine sediment. The site was in 4-6 m depth water that had a tidal amplitude of 1-2 m with currents of up to 20 cm/sec. The AC slurries were made denser than surrounding water by soaking in a 10% w/w NaCl solution, and was applied using a flexible manually opperated hose. Application rates were 20 L/min. AC mixed with clay worked best for reducing contaminant flux and minimizing effects to benthic communities. Costs of AC material was about $10/m^2 and placement costs were on the same order-of-magnitude.
What You Will Find Here:Field experiment p. 6111, Results on carbon application p. 6112, Results on reduced PAH concentrations and flux p. 6113, Effects on benthic community p. 6114
Winther, Aina. (2011). “Thin layer capping with biochar on marine sediments contaminated with PAHs, and the effect of different caps on marine sediment contaminated with dioxins.” Thesis Norwegian University of Life Sciences
Keywords:Remediation, Thin layer, Design
Summary:Capping contaminated sediment with clean materials is a remediation method that has proved efficient. Passive capping materials physically isolate the contaminated sediment from the receiving environment and active materials sorb the contaminants, thereby making them inaccessible. Activated carbon is one active capping material that is effective in reducing the diffusion of contamination from the sediment. The objective of this thesis was to investigate if biochar could be applied as an active capping material in remediating contaminated sediment. Another part of the thesis was to investigate thin layer capping with three different materials on dioxin contaminated sediment in the Grenland fjords, as a part of the Opticap project. Field work was conducted in the Ormerfjord and the Eidangerfjord in the Grenland fjords. The aim was to test the efficiency of the capping materials 1) activated carbon and clay, 2) crushed limestone, and 3) clay in order to reduce dioxin diffusion. According to the results, all caps were efficient in reducing the dioxin flux from the sediment, and the flux was the lowest in the crushed limestone field, though there are variations between the measurements. Dioxins in free aqueous phase were also reduced in the capped fields, but there were no clear trends in which cap was the most efficient, due to currents and exchange of sea water. The dioxin flux from the sediment was measured with semi-permeable membrane device (SPMD) and the dioxins in free aqueous phase were measured with polyoxymethylene (POM). The measurements were done by employing a flux chamber which was put on the sea floor and collected at different time points.
What You Will Find Here:Remediation p. 10, Thin layer capping p. 21, 40, 59 Design p. 15, (Freundlich Isotherms p. 35 )
Gerard Cornelissen, Marie Elmquist Krus, Gijs D. Breedveld, Espen Eek, Amy M.P. Oen, Hans Peter H. Arp, Caroline Raymond, Goran Samuelsson, Jenny E. Hedman, Øystein Stokland, and Jonas S. Gunnarsson. (2011). “Remediation of Contaminated Marine Sediment Using Thin-Layer Capping with Activated CarbonA Field Experiment in Trondheim Harbor, Norway.” Environ. Sci. Technol., 45 (14), pp 61106116
Keywords:Remediation, Monitoring, Field Demonstration
Summary:In situ amendment of contaminated sediments using activated carbon (AC) is a recent remediation technique, where the strong sorption of contaminants to added AC reduces their release from sediments and uptake into organisms. The current study describes a marine underwater field pilot study in Trondheim harbor, Norway, in which powdered AC alone or in combination with sand or clay was tested as a thin-layer capping material for polycyclic aromatic hydrocarbon (PAH)-contaminated sediment. Several novel elements were included, such as measuring PAH fluxes, no active mixing of AC into the sediment, and the testing of new manners of placing a thin AC cap on sediment, such as AC+clay and AC+sand combinations. Innovative chemical and biological monitoring methods were deployed to test capping effectiveness. In situ sediment-to-water PAH fluxes were measured using recently developed benthic flux chambers.
What You Will Find Here:Remediation (PAH p. 6110), Monitoring (PAH flux p. 6113, Benthic Community Analyses p. 6112, Biotic Indices p. 6115 ), Field Demonstration p. 6111,
Lampert, D.J.; Sarchet, W.V.; Reible, D.D.. (2011). “Assessing the Effectiveness of Thin-Layer Sand Caps for Contaminated Sediment Management through Passive Sampling.” Envion. Sci. Technol. 45, 8437-8443
Keywords:Thin-Layer, Sand Caps, PAHs, Pyrene, Modeling, Analytical Solution, Passive Sampling, Microcosm
Summary:Passive sampling using polydimethylsiloxane coated fibers was used to monitor PAH migration in thin-layer sand caps with bioactivity in the lab. The method for monitoring allowed for freely dissolved pore water concentrations at 1 cm increments in the cap. Measurements were compared to models where analytical solutions were provided. The passive sampling measurements were correlated with bioaccumulation in the worm, Ilyodrilus templetoni.
What You Will Find Here:Introduction p. 8437, Materials and Methods p. 8438, Analytical Solution for Bioturbation Layer p. 8440, Analytical Solutions for Isolation Layer and Combined Bioturbation and Chemical Isolation p. 8441, Bioaccumulation Predictions p. 8442
Merritt, K.A.; Conder, J.; Kirtay, V.; Chadwick, B.; Magar, V.. (2010). “Review of Thin-Layer Placement Applications to Enhance Natural Recovery of Contaminated Sediment.” Integrated Environ. Assessment and Management. 6, 4, 749-760
Keywords:EMNR, Thin-layer placement, Sediment, Monitoring
Summary:Thin-layer placement concept is discussed for sediment remediation. 3 case studies are covered and pilot-studies are highlighted. Surface sediment concentration reductions were documented at all sites. Actual risk reduction following thin-layer placement is less conclusive. Some recontamination of the thin-layer is common.
What You Will Find Here:Wyckoff/Eagle Harbor p. 750, Ketchikan Pulp Company p. 753, Bremerton Naval Complex p. 754, Other sites p. 755, Lessons Learned p. 757.
Becker, D.S.; Sexton, J.E.; Jacobs, L.A.; Hogarty, B.; Keeley, K.. (2009). “Biological responses to sediment remediation based on thin layer placement near a former pulp mill in Ward Cove, AK (USA).” Environ. Monit. Assess. 154, 427-438.
Keywords:Benthic macroinvertebrates, Organic enrichment, Sediment toxicity, Thin layer placement
Summary:Approximately 28 acres of Ward Cove, AK was covered with a thin layer of clean, fine grained sand (TOC, 0.15%) in 2001, to cover sediment with elevated ammonia and 4-methylphenol (4MP) concentrations resulting from a former sulfite pulp mill. The placement significantly reduced TOC and percent fine grained sediment in surficial layers. In general, reductions in solid phase ammonia and 4MP were observed as a result of thin-layer placement. The most noticeable change was a reduction in polychaete, C. capitata, and an increase in two bivalve molluscs, Axinopsida serricata and Parvilucina tenuisculpta, populations following thin layer placment. The change in benthic community is attributed to a reduction in organic enrichment and substrate change resulting from the placed material.
What You Will Find Here:Methods and Materials p. 429, Results and Discussion p. 432
McDonough, K. M.; Murphy, P.; Olsta, J.; Zhu, Y.; Reible, D.; Lowry, G.V.. (2007). “Development and Placement of a Sorbent-amended Thin Layer Sediment Cap in the Anacostia River.” Soil and Sediment Contamination. 16, 313-322.
Keywords:Sorbent Amendments, Coke, Geotextiles, Remediation, Thin Capping
Summary:Laminated polyester fabrics (geotextiles) can be used to apply thin layer sorbant materials followed by 15 cm of sand placement. A 1100 m^2 area, 1.1 to 5.6 m deep area in the Anacostia River was used to demonstrate this technology in 2004. Flow velocities ranged from 0.003 to 0.4 m/s and plots were contained in a silt curtain during placement. The technique did not lead to significant resuspension or recontamination of the placement area, with the exception of slight elevations of naphthalene. The mats could be placed at a rate of 100 m^2/hr with a crane and divers. Overall placement costs ranged from $29-33/m^2.
What You Will Find Here:Materials and Methods p. 316, Results and Discussion p. 319
Murphy, P., Marquette, A., Reible, D., and Lowry, G.. (2006). “Predicting the Performance of Activated Carbon-, Coke-, and Soil-Amended Thin Layer Sediment Caps..” J. Environ. Eng., 132(7), 787794
Keywords:Design, Capping, Remediation, Model Development, Attenuation
Summary:This study compares the effectiveness of commercially available sorbents that can be used to amend sand caps to improve their ability to prevent contaminant migration from the sediments into the bioactive zone. Amendments evaluated include coke, activated carbon, and organic-rich soil. The properties relevant to advective-dispersive transport through porous media sorption, porosity, dispersivity, and bulk density are measured for each material, and then used as inputs to a numerical model to predict the flux of 2,4,5-polychlorinated biphenyl PCB through a sand cap amended with a thin 1.25-cm sorbent layer. Systems with and without groundwater seepage are considered.
What You Will Find Here:Design (material selection p. 789, material characterization p. 788, groundwater seepage p. 790), Capping, Remediation (PCB), Model Development (Freundlich p. 789, Flux p. 789 – sorption, porosity, dispersivity, bulk density, simulated cap performance, half-life p. 792), Attenuation p. 791
Joseph Gailani, Douglas Clarke,Timothy Welp. (2006). “Working With Nature Beneficial Use Studies.” Presentation
Keywords:Beneficial Use Case Study, Regulatory, Planning, Cost, Monitoring, Construction
Summary:Overview presentation on beneficial use methods of placement and case study discussion.
What You Will Find Here:Beneficial Use Case Study p. 12, p. 13, p. 16, Long Distance Conveyance p. 6, Regulatory p. 8, Planning p. 9, Cost p. 10, Monitoring p. 17, Thin-Layer Placement p. 23
Onuf, C.P.. (2006). “Laguna Madre: Seagrass Status and Trends in the Northern Gulf of Mexico: 1940-2002.“
Keywords:Laguna Madre, redhead duck, shoal grass, Gulf Intracoastal Waterway (GIWW), seagrass
Summary:The history and characteristics of Laguna Madre is provided. The results of dredging the Gulf Intracoastal Waterway (GIWW) to connect the upper and lower Laguna Madre is discussed. This includes the increased turbidity caused by dredging and the resuspension of dredged material. The connection of the upper and lower Laguna Madre has caused a reduction in salinity which has opened a niche for other types of seagrass besides shoal grass, such as manatee grass and turtle grass. Dieback of the seagrass meadow has resulted in nutrient releases and algal blooms (brown tide).
What You Will Find Here:Scope of Area p. 29, Bottom cover Table 1 p. 33, Effects of Dredging p. 36, Brown Tides p. 38, USACE influence p. 39
USACE/Interagency Coordination Team (ICT). (2002). “Laguna Madre GIWW Dredged Material Management Plan.“
Keywords:Dredged Material Management Plan (DMMP), Interagency Coordination Team (ICT), Corps of Engineers (USACE), Placement Areas (Pas)
Summary:Each placement area for the Laguna Madre Gulf Intracoastal Waterway is reviewed. Best management practices are used for dispersing dredged material such ase energy dissipating devices for spreading out thin layers and decreasing the chance of burying sea grasses. Dredging windows are set from November through February when seagrass is dormant and less effected by turbidity. Generally elevated turbidity due to dredging activity is limited to an area 3/4 to 1 mile from the discharge point and remains up to 3 months after disposal is complete. It has been determined that if no more than 3 inches of dredged material is placed seagrass can recover in 3-5 years. Typical issues in the placement areas involve: hauling or pumping distances being too long for ocean disposal, recuirements of protecting seagrass, or critical habitat for piping plover or black skimmer. The preservation of cabins are also common issues with dredge material placement. The use of the placement areas for dredged material was surveyed between 1949 and 1995.
What You Will Find Here:General Guidelines p. 2, Reach 1 issues with Ocean Placement p. 3, Pas 213-219 issues p. 17, PA 221 Circulation problems p. 18, Issues with Thin-Layer Placement in Reach 5 p. 19, Erosive Currents PA 233 p. 23
Turner, R.E.. (2002). “Approaches to Coastal Wetland Restoration: Northern Gulf of Mexico.” Kugler Publications.
Keywords:Dredged Material, Thin-Layer Placement
Summary:The history of thin-layer placement is covered. Thin-layer placement thicknesses for revegetation are discussed. A case of a failed thin-layer placement on very soft sediments is disscussed. The ability to convert shallow open water to vegetated marsh is possible. Important planning considerations are listed. Cost comparisons relating high-pressure spray placement to bucket dredging are provided. Monitoring of thin-layer placement may involve different attributes of plant health and several different soil/sediment parameters.
What You Will Find Here:Dredged Material Wetlands p. 77, Thin-Layer Placement p. 115
Palermo, M.R.; Clausner, J.E.; Rollings, M.P.; Williams, G.L.; Myers, T.E.; Fredette, T.J.; Randall, R.E.. (1998). “Guidance for Subaqueous Dredged Material Capping.“
Keywords:Guidance, Dredged Material, Capping, Subaqueous
Summary:This document provides guidance for subaqueous dredged material capping. Carefully considered design, construction, and monitoring are needed. There is an interdependence between all components. The basic requirement is that the cap thickness is placed and maintained. Biological, physical, and chemical characteristics of sediment are needed. Site selection is important and should be a low-energy environment. Compatability between equipment and placement technique is required. Many types of equipment are available. Scheduling must consider both exposure of contaminated material to the environment, and other constraints. Evaluation of potential wate column effects due to placement of contaminated material must be performed. Capping is less costly than confined disposal.
What You Will Find Here:Sediment Characterization p. 16, Equipment and Placement Techniques p. 26, Sediment Dispersion and Mound Development and Site Geometry p. 51, Cap Design p. 64, Longterm Cap Stability p. 79, Cap Monitoring p. 98, Chemical Containment p. B1, LTFATE p. F1, Frequency of Erosion p. G1,
Donald R. Cahoon Jr. & James H. Cowan Jr. . (1988). “Environmental impacts and regulatory policy Implications of spray disposal of dredged material in Louisiana wetlands.” Coastal Management, 16:4, 341-362, DOI: 10.1080/08920758809362067
Keywords:Wetland Loss, High-Pressure Spray, Low-Pressure, Cost, Field Demonstration, Regulatory, Monitoring
Summary:The high pressure spray nozzle can be aimed in any direction so that the spoil can be deposited discontinuously in order to completely avoid small natural drainage streams or sensitive habitats. In saline marsh, the sprayed spoil has been observed to remain mostly in place during dredging, with little or no run-off into the canal and turbidity levels in the canal were kept low because of the use of hydraulic suction. This new disposal methodology differs importantly from conventional low-pressure hydraulic dredging and the industry standard, bucket dredging, in terms of dimensions of the spoil area, spoil deposition pattern, cost of dredging, and purported environmental impacts.
What You Will Find Here:Wetland Loss p. 342, High-Pressure Spray (Solid deposition pattern p. 345), Low Pressure Spray p. 243, Cost p. 243, p. 347, p. 359, Field Demonstration (Qualitative p. 351), Spray Dredging, Regulatory (Environmental Impacts p. 348, Policy p. 349, p. 359) Monitoring p. 360
Stevenson Environmental Services, Inc.. “Silver Lake Pilot Study Sediment Capping.“
Keywords:subaqueous cap, thin-layer lifts, geotextile, pilot study, turbidity curtain, armor stone
Summary:A one acre area was capped in Silver Lake. The pilot area was sectioned into 3 units that each received different capping treatments. Two of the areas had a geotextile placed before sand-soil mixtures. The placement of the mixtures utilized a conveyor system, mix tank, pumps, pipeline, a slurry dissipator barge, and barge structures. Turbidity curtains were installed to keep suspended solids in the remediation area. There were some challenges placing the geotextiles in the wind and waves.
What You Will Find Here:Webpage
Stern, J.H.; Colton, J.; Williston, D.. “Comparison of Monitored Natural Recovery (MNR) and Enhanced Natural Recovery (ENR) Effectiveness.” Poster.
Keywords:Dredging, Capping, Lower Duwamish Waterway, Residuals, Thin-Layer Placement, PCBs
Summary:Dredging, followed by thin-layer capping and monitoring was performed at the Lower Duwamish Waterway. Modeling to understand the effect of sedimentation on the recovery times showed timeframes of 10-20 years were required. Thin-layer capping could more quickly reduce risks of bioaccumulation in fish according to the model.
What You Will Find Here:Poster
Wilber, D. H.; Clarke, D.G.. “Defining and Assessing Benthic Recovery Following Dredging and Dredged Material Disposal.” Western Dredging Association (WEDA) conference paper
Keywords:Meta-Analysis, infauna, thin-layer, salt marsh, mud flat habitat
Summary:Benthic recovery rates range from several months to several years. If depths of placed material is limited to 20-30 cm, pre-existing benthos can migrate vertically. Areas with high wave and current energy are often held at early successional stages, and therefore recover more rapidly. Mud habitats recover faster (6-8 months) than sand and gravel (2-3 years). Proximity to unaffected areas also influences recovery time. Thin layer (< 15 cm) of beneficial use sediment in marsh habitats typically takes two growing seasons for plant recovery. Summary tables are provided. What You Will Find Here:Physical factors affecting recovery p. 604, Beneficial use p. 611