Date of Award

2000

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

First Advisor

Donald Dean Adrian

Abstract

Explosives contamination in soils is an environmental concern for the public due to their toxic effects. The United States Department of Defense (DoD) is particularly concerned with explosives contamination in soils due to the thousands of sites for which it is responsible for remediating. To date, the most common technology utilized for remediating explosives contamination in soils has been incineration. However, costs for incineration have been estimated to range from approximately $250 to $3250 per ton and are generally inversely related to the volume of soil. The use of advanced oxidation processes (AOPs), including dark and illuminated forms, was evaluated as an alternative to incineration. The dark processes involve the use of oxidizers without ultraviolet illumination. Dark AOPs evaluated during this study were Fenton's reagent (hydrogen peroxide and ferrous salts), peroxone (a mixture of hydrogen peroxide and ozone), and ultrasonics. The illuminated processes involve the use of ultraviolet illumination which supplies the photon energy to break chemical bonds. Two types of ultraviolet lights were evaluated during this study; low pressure ultraviolet light (LPUV) and medium pressure ultraviolet light (MPUV). Only soils from the Yorktown Naval Weapons Station (YNWS), Newport News, Virginia, were used. They contained approximately 1430 mg/kg trinitrotoluene (TNT), 4.5 mg/kg trinitrobenzene (TNB), 35.4 mg/kg cyclotetramethylene-tranitrainine (HMX), and 36.8 mg/kg hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Since HMX and RDX concentrations were below the treatment criteria prior to testing, TNT and TNB were the main focus. Dark AOPs were applied to soil slurries and filtrate from soil slurries while illuminated AOPs were applied to raw soil and filtrate from soil slurries. Based on preliminary evaluations, peroxone and LPUV/ozone treatment of filtrate from a YNWS soil slurry were selected for optimization. Optimization involved evaluation of treatment time, three solids loadings, and two oxidizer concentrations for each oxidizer. The optimal LPUV/ozone treatment was 20% solids and 2% ozone. The optimal peroxone treatment was 20% solids, 100 parts per million (ppm) hydrogen peroxide, and 2% ozone. Degradation rates were first order with respect to TNT, HMX, and RDX and were first order intermediate with respect to TNB.

ISBN

9780599853195

Pages

449

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