US EPA

In-Situ Containment and Treatment of Contaminated Sediments: Engineering Cap Integrity and Reactivity

EPA Grant Number: R828773C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant R828773
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (2001) - South and Southwest HSRC
Center Director: Reible, Danny D.
Title: In-Situ Containment and Treatment of Contaminated Sediments: Engineering Cap Integrity and Reactivity
Investigators: Wiesner, Mark R. , Edge, Billy , Hughes, Joseph B , Valsaraj, Kalliat T.
Current Investigators: Wiesner, Mark R. , Edge, Billy , Hughes, Joseph B , Valsaraj, Kalliat T. , Willson, Clinton S.
Institution: Rice University , Louisiana State University - Baton Rouge
Current Institution: Rice University , Georgia Institute of Technology , Louisiana State University - Baton Rouge , Texas A & M University
EPA Project Officer: Lasat, Mitch
Project Period: October 1, 2001 through September 30, 2006 (Extended to September 30, 2007)
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (2001) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

Contaminant transport and fate in sediment caps is dependent on the structure of the sediment cap, which in turn depends upon the methods used to construct the cap. Current approaches to constructing sediment caps largely focus on stabilizing or isolating underlying contaminated materials. However, variations in current construction techniques may lead to variations in contaminant transport across the cap, as well as differences in cap aging, stability and permeability. The construction of second-generation "reactive" caps will likely require a more sophisticated understanding and control of the depositional processes involved in constructing a cap. This research will address fundamental processes controlling sediment deposition as they affect the engineering of sediment caps as currently practiced, and as applied to the development of advanced capping technologies. We will test the hypothesis that the surface chemistry of conventional capping materials can be altered to achieve a desired cap structure and/or reactivity.

Approach:

A lab-scale flume will be constructed to study the effect of release methods, materials selection, and ambient conditions such as cross-flow and salinity on cap structure. Cap structure will be quantified in macroscopic terms using parameters such as permeability, porosity, and grain-size distribution. The micro-scale structure will be characterized in terms of the fractal dimension of the deposited mass. Experiments will be conducted under conditions of stagnant deposition (column studies) using suspensions of particles ranging in size from approximately 1 m to 1 mm. Mixtures of particle sizes will be investigated including deposition of fine particles onto a gravel substrate. Various surface treatments for the capping material will be investigated through the addition of polymeric materials. Changes in capping material surface chemistry (adhesion probability and adsorptive capcity) will be quantified.

In parallel with this work, simulations of particle deposition will be performed using Lagrangian methods in which the trajectories of individual particles are calculated from second-law principles. This involves the integration of the individual stochastic equations for particle motion and the calculation of individual particle trajectories from randomly selected release points over the surface. Computer models based on Monte Carlo techniques will be developed to investigate particle deposition in 3-dimensional Euclidean space on a plane. Characteristics of the simulated caps will be compared with experimentally determined characteristics to better understand limitations in the numerical model. It is hoped that such a comparison will lead to reasonable predictions of deposit morphology as function of fundamental physico-chemical parameters for a given cap-forming technique.

Expected Results:

This work will allow us to form caps with a desired set of characteristics. Better control over cap formation and methods for constructing caps where the micro- and nano-scale properties of the cap can be designed will improve our ability to control transport and targeted reactivity of contaminants within the cap. Such improvements will allow for better long-term containment and remediation of hazardous materials in sediments.

Publications and Presentations:

Publications have been submitted on this subproject: View all 20 publications for this subproject | View all 279 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 8 journal articles for this subproject | View all 63 journal articles for this center

Supplemental Keywords:

enhanced natural recovery, reactive barrier, confined aquatic disposal., RFA, Scientific Discipline, Waste, Water, Contaminated Sediments, Remediation, Environmental Chemistry, Analytical Chemistry, Hazardous Waste, Ecology and Ecosystems, Engineering, Hazardous, Environmental Engineering, contaminant transport, fate and transport , in situ remediation, contaminant dynamics, sediment caps, computer models, contaminated sediment, kinetic studies, contaminated soil, computer modeling, contaminant transport model, treatment, kinetic models, contaminant management

Progress and Final Reports:

2002 Progress Report
2003 Progress Report
2004 Progress Report

Main Center Abstract and Reports:

R828773    HSRC (2001) - South and Southwest HSRC

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828773C001 Bioturbation and Bioavailability of Residual, Desorption-Resistant Contaminants
R828773C002 In-Situ Containment and Treatment of Contaminated Sediments: Engineering Cap Integrity and Reactivity
R828773C003 Phytoremediation in Wetlands and CDFs
R828773C004 Contaminant Release During Removal and Resuspension
R828773C005 HSRC Technology Transfer, Training, and Outreach