The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	A theoretical analysis of volatile contaminant removal by the pneumatic fracturing process
Author:	Ding, Yuan
View Online:	njit-etd1995-049 (xiv, 144 pages ~ 5.2 MB pdf)
Department:	Department of Civil and Environmental Engineering
Degree:	Doctor of Philosophy
Program:	Civil and Environmental Engineering
Document Type:	Dissertation
Advisory Committee:	Chan, Paul C. (Committee co-chair) Schuring, John R. (Committee co-chair) Dauenheimer, Edward G. (Committee member) Hsu, C.T. Thomas (Committee member) Lei, George Y. (Committee member) Raghu, Dorairaja (Committee member)
Date:	1995-10
Keywords:	Fracture mechanics--Environmental aspects. Pneumatics--Environmental aspects. Volatile organic compounds--Environmental aspects. Hazardous waste site remediation.
Availability:	Unrestricted
Abstract:	A mathematical model that simulates the process of contaminant removal from a pneumatically induced fracture within a porous medium is presented. It includes: (1) model development; (2) parameter evaluation; (3) statistical sensitivity analysis; and (4) model validation. Based on the dual porosity approach, a mathematical model for a fractured porous formation is developed for both two dimensional and axial symmetrical cases. This model constitutes a pair of coupled partial differential equations for the porous medium and discrete fracture, respectively. The initial and boundary conditions have been determined based on field considerations of a soil vapor extraction system. By means of Laplace transforms, analytical solutions of the equations are obtained in explicit forms of exponential and error functions. The four principal physical parameters used in the model include tortuosity, retardation factor, fracture aperture, and extraction flow rate. Fracture aperture and flow rate are related to the characteristics of geologic formation and operational system, while tortuosity and retardation factor are related to geochemical characteristics. Guidelines for determination of these parameters are provided. In addition, a statistical analysis is performed to evaluate the sensitivity of mass removal to variations in these parameters. A linear relationship between the standard deviations of mass removal and tortuosity or retardation factor is obtained. The sensitivity of mass removal to the fracture aperture is found to be minimal; however, aperture affects mass removal indirectly through extraction flow rate. Mass removal is determined to be sensitive to flow rate in low flow ranges only.