|
Fate and Transport of PCBs in the Subsurface
SSP&A
staff served on an expert panel assembled by the Texas Eastern
Transmission Corporation. The charge to this panel was to develop
feasible remedial alternatives for sites where soil and groundwater have
been contaminated with polychlorinated biphenyl (PCB) compounds. Dr.
Charles Andrews, President of SSP&A,
served as Director of this panel that defined the chemical properties of
PCBs and their degradation products. The panel conducted laboratory and
field studies of biodegradation, surfactant chemistry and transport, PCB
transport and sorption, and DNAPL behavior in the subsurface; and
evaluated field testing methods for PCB solubilization and recovery in
fractured and porous media.
Pump and
Treat Groundwater Remediation
Dr. Chunmiao Zheng, developer of the MT3D code and liaison of SSP&A,
is currently leading an interdisciplinary research team at the
University of Alabama to develop a comprehensive framework for designing
pump-and-treat groundwater remediation systems. The project integrates
groundwater simulation, optimization, and parameter estimation
techniques to design groundwater pump-and-treat systems that meet
various physical, environmental, and budgetary constraints. The key
components of the framework are Modflow and MT3D, two of the most
popular flow and transport simulation models used in groundwater
remediation designs. These simulation models are being coupled with an
optimization model to automatically determine optimal well locations and
pumping/injection rates under realistic field conditions.
Parameterization and Predictive Analysis in Environmental Modeling
Watermark Numerical Computing (creator of PEST), SSP&A,
and the Department of Environmental Engineering, University of
Queensland are undertaking collaborative research to improve
environmental data processing through the use of numerical models,
pooling resources and expertise to improve the use of computer
simulation in environmental management. The theme of much of this
research is parameter estimation and predictive uncertainty analysis.
Performance
Limitations of Soil-Vapor Extraction as a Remedial Technology
SSP&A
participated in a comprehensive assessment of soil-vapor extraction (SVE)
as an effective technology for remediation of volatile organic compounds
(VOCs). The study was initiated as part of an evaluation of the
effectiveness of a SVE system in operation at a Superfund site. Although
the extraction system had removed a significant quantity of VOCs from
the soil, clean-up levels had not been met, and the mass of contaminant
remaining was found to be several thousand times greater than that
predicted by the initial studies on the performance of the extraction
system. Site conditions such as variability in the physical and chemical
characteristics of the soils were found to have a profound influence on
the performance of the SVE system. The research summarized the
fundamental chemical and physical phenomena that can influence the
effectiveness of SVE systems on a practical field-scale, and described
the scientific basis upon which the performance of the systems can be
evaluated and predicted. |
