Project Abstract

Development of a Systematic Methodology for Optimally Designing Vegetative Systems for Remediating Contaminated Soil and Groundwater

Principal Investigators

John C. Tracy
South Dakota State University
E-mail: TRACYJ@MG.SDSTATE.EDU

T.J. Van Lent
South Dakota State University

Vernon R. Schaefer
South Dakota State University
E-mail: SCHAEFEV@MG.SDSTATE.EDU

Goal

The goal of this project is to develop a systematic approach to the design and management of vegetative remediation schemes and to implement this approach in a decision support system that can be used by environmental professionals to evaluate the potential use of vegetative systems for remediating a contaminated site.

Rationale

Several previous and current research projects have investigated the potential for vegetation to aid in remediation of soils and groundwater that are contaminated near the soil surface. One of these projects produced models that can predict the fate of hazardous organic substances in the root zone of a soil. Preliminary comparisons between developed models and laboratory experiments were favorable, yet two significant modeling limitations were observed. First, the models could only simulate a limited number of contaminant degradation processes. Second, the models require a large amount of information about a site where vegetation is being considered as a remediation option. These limitations could prevent use of the models in predicting potential benefits of a vegetative remediation system designed by environmental professionals involved in soil and groundwater remediation projects. To overcome these limitations requires development of a methodology that can synthesize the required modeling data from information that is available about a remediation site and use the model to systematically arrive at an efficient remediation design.

Approach

Objectives of this project related to the efficient design of vegetative remediation systems will be achieved by developing a general methodology based on systems theory. This involves forming a systems statement that includes the quantitative definition of goals of the remediation project, design variables that can be manipulated to attain these goals, and practical and legal constraints that limit attainment of these goals. Several conventional and heuristic solution procedures will be used to solve the systems statement. The most robust and computationally efficient procedures will be selected for continued use in this project. Once developed, the design procedure will be applied to a field site within U.S. EPA Regions VII and VIII that has near surface soils and groundwater contaminated with hazardous organic substances. Then a graphically-based decision support system will be developed from this design experience for future use by environmental professionals.

Status

Development and analysis of conventional gradient programming solutions to solve the design systems statement, and development and analysis of heuristic solution methods to solve the design systems statement are essentially completed. Existing vegetative remediation models have been modified to incorporate a wider range of field conditions and these models are being validated. Investigators will also study the use of the modified models and design methodology to develop a pump-and-treat style vegetative remediation system. A Windows-based interface for the design and operation support system has been developed and has been applied to two field sites contaminated with hazardous organic contaminants. Preliminary results are very promising and potential applications of the program are being vigorously pursued. This project is in its third year.

Clients/Users

This project will be of interest to government agencies, such as the U.S. Department of Defense and U.S. Department of Energy, and to industry.

Keywords

Modeling, vegetation, phytoremediation, plant remediation.