United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102W)
EPA-542-N-94-009
December 1994
Issue No. 10
SPONGE TECHNOLOGY FOR GROUND WATER
TREATMENT OF METALS
By Carolyn Esposito, EPA Risk Reduction Engineering Laboratory
The Dynaphore, Inc Forager™ process streams and acid mine
Sponge is an open-celled
•cellulose sponge incorporating --
an amine-containing chelating
polymer that has selective
affinity for dissolved heavy
metals in both cationic and
anionic states. Through the
EPA'sSITE(Superfiind
Innovative Technology
Evaluation) Program, die ability
of this technology to remove
heavy-metals from contami-
nated ground water was
evaluated at the NL Industries,
Inc. site in Pedricktown, New
Jersey. The technology effec-
tively achieved a 97% removal of
copper and lead from average
influent concentrations of 917
micrograms per liter (|Jg/l) and
578 Hg/1, respectively. There
was 90% removal of cadmium
from influent concentrations of
537|Jg/l. The Forager™
Sponge can also be utilized to
remove and concentrate heavy
metals from a wide variety of
other contaminated aqueous
media such as surface water,
landfill leachate and industrial
effluents. According to the
developer, the Sponge can
scavenge metals in concentration
levels of parts per million and
parts per billion from industrial
discharges, municipal sewage,
drainage.
— Here's how the Sponge works.
The Sponge is highly porous,
thereby promoting high rates of
absorption of ions. The
polymer in the Sponge provides
ligand sites that surround the
metals to form complexes,
especially with ions of transition-
group heavy metals. The ability
of the Sponge to preferentially
bind toxic heavy metals is
particularly beneficial for the
treatment of contaminated
natural waters and has advan-
tages over conventional ion
exchange or precipitation
technologies where valuable ion
exchange sites or chemicals are
wasted because they also remove
cations such as calcium,
magnesium, aluminum, sodium
and potassium. The Forager™
Sponge's low affinity for these
cations allows these ions, for the
most part, to pass through the
system, enabling greater
absorption of toxic heavy metals.
The extent of the affinity of the
polymer for metals is influenced
by solution parameters such as
pH, temperature and total ionic
content. Absorbed ions can be
removed from the Sponge by
techniques typically employed
for regeneration of ion exchange
resins, after which the Sponge
can be reused. Alternatively, the
Sponge can be compacted for
disposal or can be incinerated.
The Sponge can be used in
columns, fishnet-type enclosures
or rotating drums. For the NL
demonstration, Sponge cubes
were confined in a fishnet taig in
a series of four columns.
Ground water was pumped
through a series of four colunms
at a treatment flow-rate of oiie
gallon per minute or 0.08 bed
volumes per minute. The
columns were situated on a
trailer-mounted unit which
included a water heater to raise
the influent temperature by:
approximately 25 degrees
Fahrenheit to increase reaction
rates. Four columns were
reportedly needed to provide
sufficient path length to meet
the demonstration treatment
goals. Although the developer
had anticipated that replacement
or regeneration of the columns
would not be necessary, some of
the columns became saturated
with cadmium and lead and had
to be regenerated during the
demonstration. The capacity of
the Sponge for copper was much
greater as none of the columns
became saturated with copper.
Although the developer's
treatment claims for copper,
cadmium and lead were achieved,
the treatment claims for chro-
mium were not met, with only
32% removal of chromium as
divalent chrome (initial concen-
trations of 426 |ig/l).
For more information and/or to get
on the mailing list for the
Innovative Technology Evaluation
Report describing the complete
demonstration, caU Carolyn Esposito
atEPA's Bisk Reduction Engineering
Laboratory in Edison, New Jersey at
908-906-6895.
THIS MONTH'S CURRENTS CONTAINS NOTES ON ONGO-
ING RESEARCH AT EPA'S ROBERT S. KERR ENVIRON-
MENTAL. RESEARCH LABORATORY.
SPONGE TECHNOLOGY 1
PCS DECHL.ORINAT10N 2
SURFACTANTS 3
RESEARCH 3
Recyclaiii/Recy elab le
Printed with Soy/Canola ink on paper that contains at least 50% recycled fiber
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fi&EteSEi
NATURAL, ORGANIC MATTER SUPPORTS
REDUCTIVE DECHLORINATION OF PCE
By Candida C. West, Robert S. Kerr Environmental Research Laboratory
Recent research has shown
that organic matter extracted
from a soil horizon was able
to support reductive dechlori-
nation of tetrachloroethylene
(PCE). Ongoing research at
the site where the soil was
collected (Sleeping Bear,
Michigan) had been con-
cerned with determining the
rates of natural in situ
biodegradation of contami-
nants; and, there was specula-
tion that the presence of high
concentrations of indigenous
dissolved or colloidal organic
matter might be contributing
to the biodegradative process.
Interaction of contaminants
with indigenous organic
matter in soil, sediment and
aquifer solids are important in
controlling their fate and
transport. Organic matter
plays a major role in sorption
and potentially serves as a
biologically available source
of carbon supporting bio-
degradative processes.
Organic carbon concentra-
tions in the vadose zone are
generally assumed to decrease
exponentially from the soil
surface becoming negligibly
low to non-existent in the
saturated zone. However,
carbon distribution at the
Sleeping Bear site is highly
complex, having buried
horizons of high organic
matter and organic films on
aquifer solids.
The primary objective of
the study highlighted here
was to determine if leachable
organic matter in the vadose
zone might provide primary
organic carbon for reductive
biodegradation of PCE. The
secondary objective was to
examine if TCE saturated
water, i.e., simulating
rainwater percolating through
TCE residual, enhanced
eidlerthe-extraction-ox———
bioavailability of the organic
matter.
Organic carbon from the
Sleeping Bear site was
extracted from a high organic
carbon spodic horizon in the
vadose zone by using two
extractants: (1) distilled
water alone, and (2) distilled
water saturated with approxi-
mately 1000 parts per million
(ppm)TCE. The soil to
solution ratio was 1:2.6 grams
per gram (g/g); and, the
solution pH for the distilled
water/soil and the distilled
water with TCE/soil was 7.6
and 7.47, respectively. After
overnight extraction, remain-
ing TCE was removed from r
the TCE/water soil extracts
by purging with N2 gas prior
to dissolved organic carbon
(DOC) analysis and micro-
cosm construction. The
concentrations of dissolved
organic carbon in the water
extract and the TCE-
saturated water extract were
16 and 20 milligrams per liter
(mg/1), respectively. The
higher efficiency of carbon
extraction using TCE
saturated distilled water was
reproduced in a second
extraction experiment;
however, the mechanism for
this additional extraction is
not clear. It has been
observed that the TCE
saturated solution extracts
more colloidal material.
Different volumes (0,10, 50,
100 milliliters) of the TCE/
—waterand~water-onljrsoil—-•—
extracts were added to
replicate microcosms contain-
ing subsurface core material.
All microcosms were spiked
with 5 ppm PCE.
Chloroethene concentrations
were monitored by purge
and trap GC analysis of
subsamples at various time
points.
The microcosms were
monitored over time to
determine the utilization
(dechlorination) of PCE.
Results of the microcosm
experiments showed the loss
of PCE and the production
of daughter products over
time for both extracts when
..present insufficientconcen- „...
trations indicating that the
extracts provide a metaboliz-
able electron donor capable
of supporting microbial
cpnsortia responsible for
reductive dechlorination of
PCE. However, we do not
yet know either the specific
identity of these compounds
or the mechanism of extrac-
tion.
Potentially any organic
substance capable of being
catabolized under anaerobic
conditions should be able to
support or "drive" reductive
dechlorination. First, the
complete degradation of lafge
or complex compounds
usually requires the activity of
different types of microorgan-
isms. Second, under anaero-
bic conditions the oxidation
of organic compounds is
-linkcdTrcrthc-rcdtitetiorrof* - -
electron acceptors other than
oxygen. Previous research
suggests that, in the subsur- ,
face, reductive dechlorination
may be only a minor factor
(less than 0.1%) for the
reduction generated during
the anaerobic oxidation
reactions.
Further research activities
are needed to identify the
specific components of the
soil organic matter being
mobilized by water and
solvent/water mixtures,
including simple aromatic
compounds and organic
acids. Attempts will be made
to enrich dechlorination
^^.^
such as ferulic acid, vanillic
acid and guaiacylglycerol.
For more information, call
Candida WestofEPA's
Robert S.Kerr Environmental
Research Laboratory at 405-
436-8551. Also, for a fuller
discussion of this research,
see: Lyon, William G.,
Candida C. West, Michelle
L. Osborn and Guy Sewell,
"Microbial Utilization of
Vadose Zone Organic
Carbon for Reductive
(continued on page 4)
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SURFACTANT CONSORTIUM AND PUBLICATIONS
The Robert S. Kerr Environ-
mental Research Laboratory has
organized a Consortium for
Surfactant-Based In Situ Aquifer
Remediation Technologies
(Consortium) and will publish
proceedings of the meetings.
The Consortium is described
below, together with informa-
tion on ordering not only
Consortium Proceedings but
also information on a recent
eraluatib'n'bfcationic'surfac-' ~"
tants.
Consortium for Surfactants
A meeting of representatives
from 11 universities, the
Department of Energy, the
Department of Defense and
the U.S. Geological Survey
and several private industries,
including surfactant technol-
ogy users and surfactant
manufacturers was held in
Norman, Oklahoma at the
University of Oklahoma on
November 30,1994. The
Consortium was organized by
Robert S. Kerr Environmen-
tal Research Laboratory
(RSKERL) personnel for the
purpose of providing a central
organization for the evalua-
tion and implementation of
surfactant-based innovative
technologies for in situ
aquifer remediation. A total
of45*parti"cipantswere —--•.--
present for the Consortium
which included a breakout
into five discussion groups
related to surfactant use:
surfactant chemistry/compat-
ibility, hydrogeology.,
microbiology, regulatory.
issues and implementation.
The consensus of the group
was that this organization
would be useful for sharing
information on developments
in research on demonstra-
tions of surfactants, to '
provide peer review of work:
plans and manuscripts on
in situ surfactant use, to
provide education on the use
and implications of surfac- •
tants in the subsurface and to
develop protocols for imple-
mentation of surfactant-
based subsurface remediation.
The Consortium is planning
to hold regular annual
meetings and to publish the
Proceedings of the meetings,!
To get on the mailing list '
for a copy of the November
1994 "Proceeding of the
Consortium for Surfactant-
Based In Situ Aquifer
Remediation Technologies,"
send a fax to Dr. Candida
West at RSKERL at 405-436-
8703 who will send you your \
copy of the Proceedings after
they are printed.
RESEARCH
The EPA's RobertS. Kerr
Environmental Research'
Laboratory (RSKERL) has
some important research in
progress relating to ground
water remedktion. What
follows is a brief description of
some of these efforts.
Surfactants.
Working under two coopera-
tive agreements with the
University of Oklahoma,
Dr. Candida West of RSKERL
is involved with research
directed at the surfactant
IN PROGRESS
enhanced remediation of
subsurface material cdhtanii-"
nated with dense non-aqueous
phase liquids (DNAPLs). The
primary emphasis of the
research is to show the
efficiency of recovery of the
surfactant solution. The first
effort, conducted by Dr. David
Sabatini, is designed to develop
an environmentally acceptable
system for enhancing pump-
and-treat systems. The
approach involves measuring
the efficiency and effectiveness
of specific classes of surfactant
systems for solubilizing and
mobilizing residual and ' ;
free-phase DNAPLs. Studies
are being carried out to test
chosen systems for ionic matrix
sensitivities, biodegradability,
solid phase interactions
and transport properties.
Dr. Robert Knox will utilize the
findings of the first phase of
the investigation to design and
conduct a small-scale field study
ofsurfactant-enhanced
contaminant removal and
surfactant recovery using a
recirculating well system at the
Cationic Surfactants
The RSKERL has pub-
lished an Environmental
Research Brief on "The Use
of Cationic Surfactants to
Modify Aquifer Materials to
Reduce the Mobility of
Hydrophonic Organic
Compounds," by John C.
Westall, Julia Wagner and
Hua Chen of Oregon State
University and Bruce J.
Brownawell of the Waste
Management Institute,
Marine Sciences Research
Center at SUNY.
A copy of the Environmental
Research Brief (Document No.
EPA/600/S-94/002) can be
ordered from CERIat
513-569-7562.
U. S. Coast Guard Station in
Traverse City, Michigan.
Ske Characterization.
An essential part of any aquifer
remedktion project is a site
characterization that provides
information necessary to select,
design, operate and evaluate an
appropriate remedial technol-
ogy. Carl Enfield at RSKERL is
working with Captain Jeffrey
Stinson under an Interagency
Agreement to thoroughly
characterize a site at Tyndall Air
Force Base using ground
(continued on page 4)
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Rtseard) continuedfiom page 3
penetrating radar and other
seismic techniques, cone
penetrometer investigations and
fiber optic spectroscopy. The
goal of the project is to deter-
mine the feasibility of using
selected technologies to enhance
the performance of a pump-
and-treat system. A second site,
selected from nine Department
of Defense test facilities, will also
be included in this investigation.
Cosolvent-Enhanosd
Remediation.
LynnWoodofRSKERLis
conducting a research project
under a Cooperative Agreement
with the University of Florida to
evaluate the feasibility of using
miscible organic cosolvents such
as alcohols to remediate
subsurface environments
contaminated by nonaqueous
phase liquid (NAPL)
hydrophobicorganic chemicals.
The project, entitled "Field-
Evaluation of Cosolvent
Enhanced In-Situ
Remediation," is being carried
out as a pilot-scale field study at
Hill Air Force Base in Utah
using sheet piling cells to provide
hydraulic containment
Chromate and TCE
Treatment
A RSKERL research team has
evaluated the use of elemental
iron as a surface treatment
alternative for chromate and
trichloroethylene (TCE)
extracted from contaminated
ground water at the U.S. Coast
Guard,Support Center at. _„ ._;-
Elizabeth City, North Carolina.
The field test involved the use of
two 55-gallon drums packed
with two different types of
elemental iron mixed with
aquifer material from the site.
Influent concentrations of
8 milligrams per liter (mg/I)
chromate, 717 micrograms per
liter (pg/T) TCE, 194 |Jg/l c-DCE
and 51 Mg/1 vinyl chloride were
used. Effluent chromate
concentrations were below
detection (0.005 mg/1) using
flow rates ranging from 0.5
to 4.0 liters per minute.
Reductions in the concentra-
tions of organic compounds
ranged from 14 to 99 percent
depending upon the flow rate.
An array of these large "col-
umns" is proposed as a means
of intercepting the leading edges
of overlapping plumes of
chromate and TCE at the site.
Potential long-term plans are to
install a permeable reactive wall
at the site composed of
elemental kon to passively
remediate both the chromate
and TCE ground water
contamination.
GROUND WATER
CURRENTS is monitoring the
progress of these research efforts.
We will provide additional
finding of this research as they
become available.
PCE continued from page 2
Dechlorination of PCE,"
_suh.n?!9~d toJOURNAL_OF
:. : ONMENTAL
,::^NCE 6-HEALTH;
Wilson J. T., D. H. Kampbell
and J. Armstrong, "Natural
Bioreclamation of
Alkylbenzenes (BTEX) From
a Gasoline Spill in Ground-
water," in R. E. Hinchee and
B. C. Alleman, eds.,
PROCEEDINGS OF THE
SECOND INTERNATIONAL
SYMPOSIUM ON IN SITU
BIORECLAMATION, .
April 5-8, 1993, San Diego,
CA; West, C. C., W. G. Lyon,
D. L. Ross and L K.
Pennington, "Investigation of
the Vertical Distribution and
Morphology of Indigenous
Organic Matter at the Sleeping i
Bear Site, Michigan, "ENVI-
RONMENTAL GEOLOGY
(in press).
MAIl-ING LIST/ORDER ttNFO
To Ortfaf additional wpie* of Own* ttfeferOmrafe or to teftvdufef on the psnaaaeat
*ribn«te« (NCEPf) at 5 \ WHWCT5, sr«w** mull «v***> NCEP), P.O.
Please refer to the doeumenr number «f*-tfee cover of *e issue ff avafeWe,
, Onctoo*.
,
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