SEDIMENT CAPPING

Application Description

As attention turns toward contaminated sediment remediation, traditional remediation methods, such as dredging and sand caps, provide widely varying results due to many environmental, operational, and economic factors. As a result, active capping continues to offer many advantages which can be tailored to each specific application, including both partial and full sediment capping.

Sediment capping involves the sub-aqueous placement of a barrier layer of material over contaminated sediment. Sediment capping reduces the potential for contaminant exposure by preventing resuspension and transport to other non-affected areas.

Problems that exist with traditional methods

• Consistency of protection
• Accuracy of mass removal techniques
• Effect of mass removal upon downstream areas
• Composition of treatable contaminants
• Space considerations of traditional sand caps
• Complexity of sub-aqueous installation
• Cost of dredging
• Cost of disposal of dredged material

CETCO Offers

• Reactive capping media available in either bulk or as a reactive mat allowing for wider variety of applications.
• Combinations of reactive core materials allow for a wide range of treatable contaminants.
• Adsorptive capacity reduces required cap thickness, thus increasing navigable depth when compared to traditional methods.
• Composite layer stabilizes sediments, minimizing re-suspension and reducing downstream impact.
• Consistent sheet size allows for highly accurate placement and maximum coverage.
• Product properties insure verifiable coverage of sediments due to fully contained, defined mass per area of reactive material.
• Reduces multi-step dredging process into fast, easily adjustable, consistent installation.
• Reductions in volume of fill material needed combined with speed of installation offer significant economic benefit.

Products

• Granular Organoclay^®, offered in both bulk and defined mass per unit area, creates a permeable barrier for contaminated soil and solids in river and stream beds.
• Organoclay MRM, specially designed for Mercury and Arsenic removal, can be used in capping applications to provide a permeable barrier in situations where either of these two metals are present in the contaminants.
• Reactive Core Mat^® is designed to provide a simple method to place active materials into subaqueous sediment caps. RCM allows for thin, stable layers of reactive media to be evenly placed in a very precise manner.
• Pro-Text 2000 – Sand Mats are designed to be placed over earthen or synthetic surfaces to guard against damage by erosion, scouring, heavy equipment or other forces.
• Bentonite Tablets offer methods to create impermeable barriers for sediment capping applications.
• Geosynthetic Clay Liners very low permeability, self sealing characteristics, and controlled quality act to isolate contaminants from contact and groundwater in sub-aqueous applications.