Date of Award

Spring 1999

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering - (M.S.)

Department

Civil and Environmental Engineering

First Advisor

John R. Schuring

Second Advisor

Paul C. Chan

Third Advisor

Edward G. Dauenheimer

Abstract

The objective of this thesis was to develop a new process for enhancing recovery wells at hazardous waste sites. The process, known as an extended radius well (ERW), involves injection of ceramic beads directly into groundwater plumes to create drainage paths for liquid contaminants. This is a variant of Pneumatic Fracturing, which is a patented in situ remediation process developed to increase permeability of soil and rock formations by injection of high pressure gas.

The research study comprised laboratory investigations, engineering scale tests, and a field pilot demonstration. The laboratory investigations examined the properties of several candidate media to determine their gradation, permeability, mechanical strength and flowability. Ultimately, ceramic beads were chosen for use in the field demonstration. Engineering scale injection tests were subsequently conducted in a 20 yd3 (15.3 m3 ) vessel filled with silty sand to establish system operating parameters.

A field pilot demonstration of the ERW process was performed at an industrial site underlain by silty fine sands containing a plume of petroleum hydrocarbons. Two ERWs were established and pumping tests performed over an 85 day period. The two ERWs displayed average increases in product recovery of 225% and 335%, respectively, compared with previous results from conventional recovery systems. Soil borings confirmed that discrete lenses extended outward from the ERWs, and model analyses attributed the observed enhancement to an increase in effective well diameter.

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