62    FULL-SCALE ELECTRON BEAM TREATMENT OF
HAZARDOUS WASTES-EFFECTIVENESS AND COSTS
Charles N. Kit rue/. Associate Professor
Department of Management Science
Thomas D. Waite, Professor
Department of Civil Engineering
University of Miami
Coral Gables, Florida 33124
William J. Cooper, Director
Michael G. Nickelsen, Research Associate
Drinking Water Research Center
Florida International University
Miami, Florida 33199
INTRODUCTION
Extensive research regarding the effectiveness of high energy electrons in treating aqueous based
waste streams has been conducted over the last year and one half. The full scale research facility at the
Virginia Key Wastewater Treatment Plant in Miami, Florida includes a 1.5 MeV, 50 ma electron
accelerator and is plumbed to handle waste flow at 120 gpm. Source streams connected directly to the
plant are potable water, chlorinated oxygenated secondary effluent, and sludge containing 2 to 8%
solids. Six thousand gallon tank trucks can also be connected to the plant influent lines for large batch
experiments.
Bacterial disinfection experiments have been conducted as well as experiments on halogenated and
aromatic organic compounds such as 1,1,1 trichloroethane, trichloroethylene(TCE), chloroform,
benzene and toluene.1,2,3 Recent efforts have concentrated on these and other hazardous organic
compounds regulated by the USEPA and identified as frequently occuring wastewater and groundwater contaminants.
This paper will present a description of electron beam technology, summarize the removal effectiveness of the process based on experiments conducted to date, and provide first approximation cost
estimates of full scale treatment.
ELECTRON BEAM TECHNOLOGY
Electron beams have been in commercial use since the 1950s. Early applications involved the
crosslinking of polyethylene film and wire insulation. The number of applications has since grown to
include sterilization of medical supplies, rubber vulcanization, disinfection of wastewater, food preservation, curing of coatings, etc. Today there are several hundred electron processing systems
installed for industrial applications in over 25 countries.
Electron beam processing involves exposing the material to be irradiated to a stream of high energy
(fast) electrons. These electrons interact with the material in less than 10"12 seconds to produce
electrons of lower and lower energy. Eventually a large number of slow electrons with energies less
than 50 eV is produced and these electrons interact with molecules to produce excited states of these
molecules, positive ions and electrons. Eventually the electrons slow to thermal energies and get
trapped. In materials of low dielectric constant most electrons do not escape the pull of the positive
ions formed when they were produced. The electrons are attracted back to the positive ions causing a
chemical reaction. This is termed direct radiolysis. In high dielectric materials such as water and
aqueous solutions, most electrons escape the pull thus leaving both the positive ions and electrons free
to react with the water or waste components in it. This is referred to as indirect radiolysis. Since the
ratio of direct to indirect radiolysis of a waste is approximately the weight fractions of waste to water4
the radiolysis of water is the primary mechanism of destruction using high energy electrons. The
45lh Purdue Industrial Waste Conference Proceedings, © 1991 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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