United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
 Research and Development
EPA/600/S2-85/108  Dec. 1985
Project  Summary
Destruction  of PCBs—
Environmental  Applications  of
Alkali  Metal  Polyethylene
Glycolate  Complexes
Frank J. laconianni
  This project is a follow-up on a study
 which focused primarily on the feasib-
 ility of chemical detoxification of PCB-
 contaminated soil using Franklin  Re-
 search  Center's (FRC's NaPEG) Rea-
 gents. The research described in the full
 report involves primarily a laboratory
 study of Sodium Polyethylene Glycol,
 the most effective NaPEG Reagent in
 terms of reactivity and stability.  The
 study was aimed at identifying treat-
 ment conditions necessary for the most
 efficient decontamination in field appli-
 cations. On-site and off-site field veri-
 fication studies were also conducted
 using PCB-contaminated soil from spills
 in Buffalo, NY and Philadelphia. PA.
  I n the first phase of this study, experi-
 ments using soils contaminated in the
 laboratory were presumed to demon-
 strate that the concentration of PCBs in
 soil can be reduced to below 50 ppm by
 direct addition of the NaPEG reagent
 under ambient conditions typical of an
 in-situ treatment of a spill.
  Laboratory tests conducted during the
 second phase of this project  centered
 mainly  on the treatment of PCB-con-
 taminated soil obtained from the two
 spill sites mentioned above. The effects
 of variable reaction parameters which
 affect the rate of decontamination were
 examined in detail.
  This Project Summary was developed
 by EPA's Hazardous Waste Engineering
 Research Laboratory, Cincinnati, OH,
 to announce key findings of the research
 project that is fully  documented in  a
 separate report of the same  title (see
Project Report ordering information at
back).

Introduction
  The accumulation of polychlorinated
biphenyls (PCBs) and polychlorinated
dibenzodioxinsfPCDDs, "dioxins")insoil,
sand, and living tissue is  a  serious
problem. Although a great amount of
work has been done in the area of direct
chemical  decomposition  of these  and
other halogenated organics, relatively
little effort has been directed toward in
situ chemical detoxification.
  The "cleanup" of a contaminated site
usually involves landfilling  and is not
really a permanent  detoxification but
rather a transfer of a toxic spill from one
location to another. Landfilled toxic ma-
terials are still in the environment and
will persist there until they are chemically
destroyed.
  In the  chemistry  laboratory  at the
Franklin Research Center (FRC) during
the summer of 1978, a chemical reagent
was synthesized for use to dechlorinate
PCB oils. Since that time a series of
reagents have been developed  and are
now called MaPEGtm* Reagents. They are
essentially alkali metal polyethylene gly-
colates which produce rapid dehalogena-
tion  of halo-organic  compounds of all
types—in open air systems.
  The aerobic nature of the  NaPEG
System immediately suggested its poten-
"Mention of trademarks or commercial products does
 not constitute endorsement or recommendation for
 use by the U S. Environmental Protection Agency.

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tial for use on hazardous chemical spills.
In August 1 979, the U.S. Environmental
Protection Agency (EPA) provided grant
support to FRC to investigate the chem-
istry underlying the dehalogenation pro-
cess, concentrating on dechlorination of
PCBs. Subsequent EPA grant assistance
was provided for a limited field study of
the effects  of a NaPEG  reagent on PCB-
contammated soil.  This  research  was
described in a Project Summary entitled
"Dehalogenation  of PCBs  Using   New
Reagents Prepared from Sodium Polyeth-
ylene Glycolate—Application to  PCB
Spills and Decontaminated Soils," August
1982.
  Additional EPA grant assistance was
awarded in 1982 for the detailed investi-
gation of the effects of  variable reaction
parameters on  the rate  and extent of
chemical decontamination  of the  sub-
strate. This research focussed almost
exclusively on the direct chemical treat-
ment of PCB-contaminated soil.  The
continued  laboratory investigation was
aimed at identifying treatment conditions
necessary  for the most efficient decon-
tamination in a  direct  field application.
During the study an optimum  reagent
composition was selected based on chem-
ical  considerations. Maximum reactivity
toward   PCBs and other halogenated
organics coupled with  minimum sensi-
tivity to  reagent-deactivating side  reac-
tions was  sought in selecting the best
reagent formulation for further study. The
full  report  describes the research per-
formed and the results obtained.
 Early Experiments Using
 Laboratory-Contaminated Soils
  Laboratory experiments using simu-
 lated soil substrates spiked with  PCBs
 confirmedthat PCBs aredechlorinated by
 the NaPEG Reagents under mild, ambient
 conditions. Subsequent experiments us-
 ing actual soils spiked with PCBs clearly
 show, however, that water in soil greatly
 reduces the rate of dechlorination and the
 effectiveness of the reagents on PCBs in
 real soils These adverse effects  were
 greater than expected from the prelim-
 inary results obtained in previous studies.
 In addition,  it was found that  the most
 effective  reagent formulation for  the
 dechlorination of PCBs in controlled one-
 phase reactions  and  model substrates
 was not the most effective reagent for
 PCBs in  soil, specifically because of its
 extreme sensitivity to water. The reagents
 described in the full report are much less
 sensitive to deactivation with water.
  The next phase of experiments show
that soil freshly contaminated with 1000
ppm of Aroclor 1260 can be decontam-
inated to below 50 ppm PCBs  in only a
few days with a direct  application of
Potassium  Polyethylene  Glycol (KPEG)
350-1. Particularly  encouraging is the
fact that this reagent can be used on soil
containing some water and organics, and
that it continues to  react after several
days in open air

On-Site Treatment of
PCB-Contaminated Soil
  The first completed on-site experiment
in the application of reagent  to contam-
inated soil was carried out by FRC per-
sonnel in Buffalo, NY, in  August 1983.
This experiment produced inconclusive
results in contrast to those obtained under
laboratory-controlled conditions.
  The only known major problem which
has adversely affected the results of this
initial field study involves the inhibiting
effect of water on the chemical degrada-
tion rate.  Subsequent  laboratory tests
demonstrated simple techniques that may
be used to minimize the adverse effects of
water on the rate of decontamination.
  The results of more recent, systematic
laboratory investigations are much more
encouraging than the preliminary on-site
test. The level  of PCBs in contaminated
soil can be reduced from  approximately
1000 ppm (highly contaminated) to below
50  ppm  by  direct chemical treatment
under relatively mild conditions. This
suggests that the direct on-site chemical
treatment of PCB-contaminated soil is a
promising process.
  Results using PCB-contaminated soil
from the Philadelphia, PA, site  showed
that significant dechlorination is achieved
by  simply air  drying the  soil  at room
temperature prior to the application of the
reagent. Without this pretreatment, in-
significant  decontamination was ob-
served for the relatively wet soil, even
when KPEG350-1 was used.
  When the soil sample  was  obtained
from the site in May 1984, it was noticed
that the treated soil was  still very wet.
Also, water condensation was observed
under the plastic sheet that covered the
plot. The sheet may keep the rain out, but
it also tends to keep moisture in. This was
probably not a  major disadvantage, how-
ever, because  without the cover, all but
the soil  particles closest to the surface
would retain most of their excess mois-
ture, even in extremely dry atmosphere.
In light of this, thorough mixing of the soil
in air, prior to reagent application, should
be an essential minimum pretreatment.
   Excess water, if not adsorbed, can be
 easily removed by exposing all of the soil
 to the surface, even at ambient temper-
 atures.  If such a treatment is performed
 on-site, especially on a warm, dry day, the
 promising  results obtained in the  labo-
 ratory tests may be verified. At this time,
 the various inhibiting effects of water are
 the  only known major problems which
 have adversely affected the results of this
 initial field study.  Air drying is a very
 important  step which should  greatly
 minimize these effects in field tests.
   The on-site treatment of soils contam-
 inated with PCBs and other halogenated
 aromatics looks very promising, based on
 the  results obtained in the laboratory
 studies. Considerable work remains to be
 done in the area of process development,
 particularly with respect to reducing the
 inhibiting effect of water and optimizing
 conditions for soil decontamination.
  Various solvent pretreatment and soil
heating  methods, for  example, deserve
additional and scaled-up  investigation.
Some of these techniques are currently
being studied  in the laboratory.  Field
testing must continue, however, not only
to verify laboratory results, but to provide
first-hand experience in real-world situa-
tions that is necessary for the develop-
ment of  a field process.


Conclusions
  The results of the overall study show
that  FRC NaPEG  Reagents can signif-
icantly reduce the concentration of PCBs
in contaminated soils under  controlled
laboratory conditions. There  are,  how-
ever, several areas in which improvement
and  optimization  must be achieved  in
order to develop a viable and economical
process  for  chemically treating PCB-con-
taminated soils in the field.  The most
recent results  of laboratory experiments
suggest that:

 • Application of reagent to wet soil is not
   as effective in reducing the concentra-
   tion of PCBs. The water present in a
   typical reaction sample greatly dilutes
   the reagent. Air  drying of  the soil is
   necessary prior to treatment.
 • Increased temperature is, as expected,
   more effective in reducing PCB  con-
   centration in soils.
 • Increasedtemperaturealsoeases mix-
   ing of reagent and soil; this should aid
   the continued reduction of PCB in soil
   over a period of time.
 • An increase in reaction time shows
   continued decrease in the concentra-

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tion of PCBs in the soil, particularly of
the more active components
A  greater reagent to soil ratio  has
shown the best results. This is likely
due  in part to increased contact of
reagent with PCBs  This effect  can
perhaps  be duplicated  by  a better
method of  mixing.  In addition, in-
creased reagent to soil  ratio means
less  soil  water contamination in the
reagent. This should also increase the
rate of dechlorination.
The syringe application method, which
minimizes the amount of atmospheric
water  coming  in  contact with  the
reagent,  is  sufficient; no additional
advantage is realized by applying the
reagent to the soil under nitrogen.
Kerosene added to the soil as a solvent
pretreatment is more effective in real-
izing dechlorination than toluene, or
no solvent at  low reaction tempera-
tures, but not significantly more effec-
tive  than no solvent pretreatment,
when  reactions are conducted at
higher temperatures.
The reagent diluted with kerosene or
toluene prior to application to the soil
is not as effective in dechlorinating the
PCBs as the reagent alone applied to
the soil.
Frank J. laconianni is with Franklin Research Center, Philadelphia, PA 19103.
Charles J. Rogers is the EPA Project Officer (see below).
The complete report, entitled "Destruction of PCBs—Environmental Applications
  of Alkali Metal Polyethylene Glycolate Complexes," (Order No. PB 86-105
  293/AS; Cost: $11.95, subject to change)  will be available only from:
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
        Hazardous Waste Engineering Research Laboratory
        U.S. Environmental Protection Agency
        Cincinnati, OH 45268

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
     BULK RATE
POSTAGE & FEES PAID
        EPA
   PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-85/108

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