United States
Environmental Protection
Agency
EPA/540/F-92/009
October 1992
&EPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION I
Emerging Technology Bulletin
Electron Beam Treatment for Removal of Trichloroethylene and
Tetrachloroethylene from Streams and Sludge*
Florida International University and the University of Miami
Technology Description: Irradiation of aqueous solutions
with high-energy electrons results in the formation of the aqueous
electron, &a , hydrogen radical, H-, and the hydroxyl radical, OH-.
These reactive transient species initiate chemical reactions ca-
pable of destroying organic compounds in aqueous solution, in
most cases, oxidizing them to carbon dioxide, water, and salt. No
sludge is formed and no pretreatment is necessary. The reaction
by-products are non-toxic and thus this process represents a new
technology for the restoration of contaminated water, soils, and
sediments.
At one end of the system, an aqueous solution containing the
hazardous organic chemical(s) is directed over a weir where it
falls in a thin sheet (approximately 4 millimeters thick). At the
other end of the system, a 1.5-million volt insulated core trans-
former (ICT) electron accelerator generates electrons and accel-
erates them to about 97% the speed of light. These accelerated
'This is the firstin aseries of bulletins thatwill report results of research conducted
through this cooperative agreement.
electrons are propelled in a concentrated beam down a high-
vacuum tube toward a scanner that scans the beam to a rectan-
gular ishape and directs it toward the aqueous solution that is
flowing over the weir. It is at this point, when the electrons
penetrate the waste stream, that treatment occurs. Studies were
conducted at 120 gal/min and can be easily scaled up for larger
applications (Figure 1). The process is essentially pH indepen-
dent in the range 3-11.
Waste Applicability: This process can treat complex mix-
tures 'of hazardous chemicals in drinking water, groundwater,
wastewater, and water containing up to 5% suspended solids. It
can tie used to remove various organic chemicals including
chloroform, bromodichloromethane, dibromochloromethane,
bromoform, carbon tetrachloride, TCE, PCE, frans-1,2-
dichloroethene, c/s-1,2-dichloroethene, 1,1-dichloroethene, 1,2-
dichloroethane, hexachloroethane, 1,1,1-trichloroethane, 1,1,2,2-
tetraclnloroethane, hexachloro-1,3-butadiene, methylene chloride,
benzene, toluene, chlorobenzene, ethylbenzene, 1,2-dichloroben-
Vault Exhaust Fan
Window
Exhaust Fan
ICT Controls
Influent
Controls
1.5MeV50
mAICT
Electron
Accelerator
Treated Effluent
Sampling Area
Vault Exhaust Duct
Influent Line
Figure 1. Elevation of the Electron Beam Research Facility, Miami, FL
Printed on Recycled Paper
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1,3-diehlorobenzene, 1 ,4-dfchlorobenzene, m-xylene, o-
xylen®, dieldrsn, and phenol,
Results: Several different experiments with electron
b«am irradiation of aqueous streams were conducted. These
experiments had as their focus the effect of water quality, solute
coacettlraifon, and Irradiation dose on removal efficiency for TCE
and PCE, To develop a more quantitative understanding of the
factors that affect the removal efficiency of TCE and PCE from
water by electron beam, experiments were designed that in-
cluded the variables identified as important in the preliminary
studies, 1,9,, total carbonate alkalinity, bicarbonate/carbonate ion
spacfatfort, solute concentration, and tha presence and absence
of clay. The waters used for the detailed experiments were
potable water and raw and secondary wastewaters* Potable
water is delivered to the plant with a pH of approximately 9 and
an aJMiniiy ol 45 to 80 mg L* as CaGO3, For these conditions
the tfcsbooa$e,ibarbonate fon speciatfon is 7.41 x 10-* M / 4,77 x 10*
H respectively. By lowering the pH of the wafer, using concentrated
HCl, to pH ?, the specEatfon is afiered to 6.98 x 1&< M / 4. 93 x 1Q-7M.
Add Atonal HCf lowered the pH to 5 and essentially eliminated the
OMbooaSa al
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