Environmental Innovative In-Situ Remediation of Restoration ER-1501 Contaminated Sediments for Simultaneous Control of Contamination and Erosion
Background:
Current technologies for remediating contaminated sediments include removal followed by treatment and disposal; in situ isolation of the sediments from the environment by covering the sediment with a sand or gravel cap (i.e., passive capping); and monitored natural recovery, which involves monitoring processes that isolate, degrade, transform, and immobilize contaminated sediments under natural conditions. However, these remedial alternatives offer only temporary solutions, do not address a wide variety of organic and inorganic contaminants, may not be applicable for both marine and freshwater sediments, and may be destructive to the benthic environment.
cross-link networks to act as plugging agents that bind and stabilize metals, radionuclides, and other contaminants (e.g., PAHs) in porous media, while being stable to biodegradation. Phosphate amendments, organoclays, and the cross-link products of one or more biopolymer products will complement each other to stabilize a wider range of organic and inorganic compounds than any of them could individually. Moreover, the liquid amendment (phytate) may penetrate and disperse after surface application to stabilize deeper sediments and retard the release of contaminants in the event of future disturbances of the surface.
Objective:
The objective of this project is to develop an active capping technology that contains and stabilizes a wide range of contaminants (metals, polycyclic aromatic hydrocarbons [PAH], and polychlorinated biphenyls [PCB]) in different aquatic environments (marine and freshwater) by designing in situ stabilization treatments that combine chemical and biological amendments. The system will simultaneously reduce contaminant toxicity and/or bioavailability while creating a resistant barrier that reduces the disturbance of subsurface sediments, thus combining many of the advantages of active and passive methods. Stabilization mechanisms as well as physical, chemical, and biological processes occurring within the active cap and top sediment layer will be investigated.
Contaminant processes in a broad range of environments will be addressed by novel active caps.
Expected Benefits: Process/Technology Description:
The active capping technology will consist of in situ application of phosphate materials (apatite and calcium phytate), organoclays, and biopolymer products. Solid amendments that settle to the bottom will be introduced first while soluble compounds (phytate and biopolymer products) will be injected into the solid layer, although researchers will investigate additional ways to minimize dispersal of water-soluble compounds. The amendments will be tested individually and together in different proportions as an active capping layer applied to the top layer of sediments. The treatment is based on the proven ability of phosphate-based materials to stabilize metals and radionuclides, of organoclays to bind nonpolar pollutants such as PCBs and PAHs, and of biopolymers and their Active capping has the potential for in situ remediation of a variety of contaminants in a range of sediments while providing long-term stabilization. This project also will improve understanding of chemical and biological processes in treated sediments. (Anticipated Project Completion 2009)
Contact Information:
Dr. Anna Sophia Knox Savannah River National Laboratory Building 773-42A-231 Aiken, SC 29808 Phone: (803) 725-7021 Fax: (803) 725-7673 E-mail: anna.knox@srnl.doe.gov
REVISED 08/02/06