United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102W)
EPA-542-N-95-006
September 1995
Issue No. 13
<3rERA Ground Water Currents
Developments in innovative ground water treatment
** NEWS FLASH **
** GROUND WATER REMEDIATION CENTER **
By Rich Steimle, EPA Technology Innovation Office
The EPA has selected the
National Environmental
Technology Applications
Center (NETAC) to es-
tablish and operate the
National Ground Water
Remediation Technology
Center. The purpose of
this new Center is to pro-
mote innovative technolo-
gies to clean up contami-
nated ground water. It
will compile, analyze and
disseminate information
on new ground water
remediation technologies.
The Center will maintain
an active outreach pro-
gram; and, its activities
will be guided by an exter-
nal Guidance Committee
composed of representa-
tives from interested pub-
lic and private sector
organizations. As such, it
will serve as a principal
voice for describing and
promoting the application
of the latest ground water
technologies throughout
the country. Information
from the Center will be
available to everyone.
The kinds of informa-
tion collected and distrib-
uted will focus on in situ
ground water remediation.
This information will in-
clude the status and re-
sults of research, develop-
ment and demonstration
activities; the identifica-
tion of leading researchers
and practitioners; and
patent and license agree-
ments. Tbe Center will
analyze the information
and report on the status
and trends of each tech-
nology. The information
on research activities will
be organi/ed as to status,
i.e., bench scale studies,
controlled field investiga-
tions, field demonstra-
tions and accepted use;
documentation will be
noted.
The Center will be lo-
cated within the NETAC
facilities at the University
of Pittsburgh Applied Re-
search Center (U-PARC)
in Harmarville, Pennsylva-
nia, where it will be oper-
ated in association with
the Environmental Engi-
neering Program at the
University of Pittsburgh
(Pitt). Dr. Edgar Berkey,
President of NETAC, will
serve as Center Director.
Dr. Frederick G. Pohland,
who holds the Edward R.
Weidlein Chair of Envi-
ronmental Engineering at
Pitt will be Associate
Director. The Center's
activities will be coordi-
nated closely with the
Technology Innovation
Office of EPA, which is
directed by Dr. Walter W.
Kovalick, Jr. Center re-
ports will be prepared by
technical teams drawn
as appropriate from
NETAC, Pitt and other
supporting institutions,
including Carnegie-
Mellon University.
NETAC was chosen by
EPA through a competi-
tive process. The award
is for a three-year base
period funded annually
at $250,000 per year.
GROUND WATER
CURRENTS will report
from time to time on the
developments and prod-
ucts of the Center.
For more information on
the Center, call Dr. Berkey
at 412-826-5320 or Dr.
Pohland at 412-624-
1880.
THIS MONTH IN CURRENTS
NEW CENTER
SOIL PLUGGING
VIDEO
VISITT 4.O UPDATE
PERVAPORATION
SITE SEARCH
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CENTER SUBJECTS
A SOLUTION TO BIOREMEDIATION'S SOIL PLUGGING
By Peter R. Jaffe, Ph.D., Princeton University
The results of research
sponsored by EPA's North-
east Hazardous Substances
Research Center (HSRC)
have direct application for
the design of in situ bio-
remediation of contaminated
ground water. The research
results clearly show under
what conditions soil clogging
occurs and how to mitigate
this problem.
Manipulating the ground
water by adding constituents
that enhance the growth of
microorganisms can cause
the soil to become plugged
or clogged — that is, gases
and water are no longer able
to flow through it freely.
Several factors can lead to
clogging of soils during in
situ bioremediation, includ-
ing the accumulation of
biomass in soil pores; the
precipitation of chemicals
such as iron, which can
occur as the oxygen in
ground water increases; and
the entrapment in soil of
small gas bubbles formed by
bacterial metabolism.
Biomass, precipitates and gas
bubbles all reduce the area
through which the water can
flow in the soil. If such
clogging occurs, pumping
and controlling the ground
water flow in the subsurface
will be difficult; the bio-
remediation design may even
fail.
The research focused on
identifying which types of in
situ bioremediation designs
are more likely to have
clogging; in what types of
soils clogging is more likely to
occur; and how to design and
operate a bioremediation
scheme in order to minimize
clogging of soils. In order to
address these issues, a com
puter model was developed
BIOREMEDIATION VIDEO
The Great Lakes/Mid-At-
lantic Hazardous Substances
Research Center has pro-
duced a training videotape
on bioremediation. The
video is designed to help
train state and local govern-
ment regulators in the el-
ementary concepts of
bioremediation. It defines
commonly used terms, dis-
cusses both in situ and engi-
neered reactor approaches to
bioremediation and identi-
fies some of the criteria that
establish the site- and chemical-
specific characteristics for
remediation. This video was
developed by The University
of Michigan and produced by
Michigan Stai:e University with
support from EPA's Bioreme-
diation Action Committee.
The video can be purchasedjbr
$35 by contactmgMichael Berger
by telephone at. 113-763-1312: by
FAX at 936-2195; or by mail at
The University of ^Michigan, 2028
Dana Building Arm Arbor, MI
48109-1115.
that simulates the accumula-
tion of biomass in the soils.
This computer model was
based on results of laboratory
studies on the physics of soil
clogging by biomass. With
the aid of this model, re-
searchers at the Northeast
HSRC investigated clogging
during in situ bioremediation
of contaminated ground
water sites having different
soil and pollutant properties.
The results of this research
project have shown that
heterogeneous soils are more
likely than homogeneous soils
to exhibit clogging during in
situ bioremediation. This
potential for clogging has
been expressed in terms of
soil-type parameters used in
soil physics, such as a pore-
size distribution index, which
gives engineers and geo-
hydrologists a tool to assess
the potential for clogging in a
specific soil condition. In
terms of the pollutant itself, it
was shown that clogging will
be most severe in the vicinity
of injection wells when the
bioremediation design
requires that a specific
substrate for the microorgan-
isms and oxygen both be
injected simultaneously. The
model developed in this
project was used to illustrate
how to operate such injection
wells in order to minimize soil
clogging. By alternating the
injection of the food source
and the oxygen, the research-
ers estimated that the injec-
tion pressure at the injection
well could be reduced tenfold.
For more information, call
Peter Jaffe at Princeton Univer-
sity at 609-258-4653. See
also: Taylor. S.W. andPR.
Jaffe, "Enhanced In Situ Biore-
mediation and Aquifer
Permeability Reduction,"
JOURNAL OF ENVIRON-
MENTAL ENGINEERING,
ASCE,VoL 117, No. I, Jan.
1991, pp. 25-46.
VISITT UPDATE
EPA has updated the Ven-
dor Information System for
Innovative Treatment Tech-
nologies (VISITT).
VISITT 4.0 is an electronic
database that features 48
new vendors and now pro-
vides data on a total of 204
companies offering 325
technologies in 32 technol-
ogy categories. There are
236 full-scale, commercially
available technologies, an in-
crease of 35 full-scale tech-
nologies. The technologies in
VISITT have the potential to
treat a wide range of contami-
nants. The number of
VISITT 4.0 technologies that
will treat volatile organics in-
creased almost 20% from
VISITT 3.0. The number of
technologies which will treat
metals increased 30%,
semivolatile organics and
(continued on page 4)
Ground Water Currents
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SITE SUBJECTS
UPDATE ON ZENON PERVAPORATION
By Ron Turner, EPA National Risk Management Research Laboratory
The ZENON cross-flow
pervaporarion system em-
ploys a membrane to remove
volatile organic compounds
(VOCs) from aqueous ma-
trices contaminated with
liquids such as solvents,
degreasers and gasoline.
VOCs with water solubilities
of less than 20,000 parts per
million (ppm) are generally
suited for removal by
pervaporation. Pervaporation
provides an alternative ap-
proach to treating organic-
contaminated water at sites
where conventional air strip-
ping or carbon adsorption
are under consideration for
use. Unlike air stripping,
pervaporarion releases negli-
gible amounts of VOCs to
the outside air. Unlike acti-
vated carbon, the treatment
medium does not require
frequent replacement and
disposal. Periodic cleaning
of the membranes is neces-
sary to maintain the treat-
ment efficiency. The full-
scale ZENON system cm
be easily tr.msported and
requires only an electric il
source.
ZENON was evaluated
during a SITE (Superfund
Innovative Technology
Evaluation) full-scale dem-
onstration at a former waste
disposal area at Naval Air
Station N( irth Island in San
Diego, California in Febru-
ary 1995. The demonstra-
tion was cc inducted as a
cooperative,' effort among
EPA, ZENON, the Naval
Environmental Leadership
Program, Environment
Canada and the Ontario
Ministry of Environment
and Energy. Long-time
readers of GROUND WA-
TER CURRENTS may re-
call that we first reported in
our June 1994 issue (EPA
542-N-94-005) the good re-
sults from the Canadian
government's pilot scale
demonstration of Zenon's
pervaporation process. At
Naval Air Station North Is-
land the ground water con-
tained elevated concentra-
tions of trichloroethylene
(TCE), as well as other con-
taminants. The TCE influ-
ent concentrations were up
to 250 ppm. The Zenon
pervaporation system re-
moved about 98% of the
TCE at a flow rate of 10 gal-
lons per minute or less. The
average TCE concentration
in the treated water was ap-
proximately 1,380 micro-
grams per liter. Air releases
were minimal.
The ZENON membrane
material is a nonporous
organophilic polymer,
such as silicone rubber,
formed into capillary fibers
measuring less than one mil-
limeter in diameter. Silicone
rubber is highly permeable to
organic compounds and re-
sistant to degradation. The
capillary fibers are aligned
parallel on a plane and
spaced slightly apart. This
arrangement of fibers forms
one membrane layer. Sepa-
rate membrane layers are
aligned in series, with the in-
terior of the capillary fibers
exposed to a vacuum (about
one pound per square inch,
absolute). The number of
membranes used in a par-
ticular system depends on
expected flow rates, contami-
nant concentrations in the
untreated water and target
concentrations for contami-
nants in the treated water.
For the demonstration,
contaminated water was
(continued on page 4)
SITE SEARCH -- NAPL CONTAMINATED SITE WANTED
EPA's National Risk Man-
agement Research Laboratory
(NRMRL) in Ada, Okla-
homa is conducting an evalu-
ation of innovative technolo-
gies for extracting nonaque-
ous phase liquids (NAPLs)
from subsurface environ-
ments. NRMRL is searching
for a second site to repeat an
evaluation currendy in
progress at Hill Air Force
Base (Hill AFB), Utah where
ten side-by-side evaluations
are being conducted in highly
controlled cest cells con-
structed with scalable joint
sheet piles keyed into a clay
confining layer. The first
approach tested used spirit
grade alcohol for solubilizing
thecontan linants. The
cosolvent was successful in re-
moving from 80% to 100%
of the target constituents in
approximately ten pore vol-
umes. The remaining tests at
Hill AFB v/ill be completed
before the end of fiscal year
1996.
The research program calls
for repeating the evaluation at
additional sites with different
hydrologic environments. We
are seeking a highly contami-
nated NAPL site which meets
the following minimum crite-
ria: (1) the site must be on
government property; (2) the
confining layer must be
within 40 feet of soil surface;
and (3) site owners and regu-
lators should be willing to
actively support the activity.
A short list of proposed sites
will be prepared by the
middle of October 1995.
Work is scheduled to begin in
the Spring of 1996. Field
work at the site will be com-
pleted by the Summer of
1999.
Those interested in proposing a
potential test site should contact
CarlG. Enfield, NRMRL, Ada,
Oklahoma at 405-4363530.
Ground Water Currents
-------
(VISITTfrom page 2)
other organics increased 15%
and 65% respectively.
EPA has made the V1SITT
4.0 software and user manual
available for downloading
(free) on the Internet acces-
sible Clean-Up Information
Bulletin Board System
(CLU-IN). For instructions
on downloading VISITT
from these resources, contact
the VISITT HELP LINE at
800-245-4505 or 703-883-
8448. VISITT software is
also available from EPA's File
Transfer Protocol (FTP)
site on the Internet
(FTP.EPA.GOV). It can
also be obtained from the fol-
lowing electronic information
resources: America Online
(AOL); Defense Environ-
mental Network for Informa-
tion eXchange (DENDQ
(Telenet: 128.174.5.51).
VISITT 4.0 diskettes (3.5")
and user manual can be ob-
tained by sending a request
to EPA/NfCEPI either by
mail (P.O. Box 42419, Cin-
cinnati, OH 45242-0419) or
by FAX (513-489-8695).
EPA requests that, whenever
possible, you download di-
rectly from one of the elec-
tronic bulletin board.s rather
than ordering the diskette
due to limited funds tor du-
plicating diskettes.
(ZENON'from page 3)
pumped from an equalization
tank thr< >ugh a prefilter to re-
move debris and silt particles
and then into a heat ex-
changer rJhat raised the water
temperature to about 165 de-
grees F (75 Degrees C). The
heated contaminated water
then flowed into a perva-
poration module that con-
tained dense polymeric mem-
branes. The organophilic
composition of the mem-
brane caused the organics to
adsorb to the membrane
(capillary fibers). The organ-
ics migrated to the interior of
the capillary fibers and were
then extracted from the
membrane by the vacuum.
Contaminated water that
passed through the
pervaporation module was
depleted of organics and ex-
ited the ZENON system for
sewer discharge. The organic
vapor (called permeate) that
adsorbed to the membrane
and which was extracted by
vacuum was condensed and
vented downstream of the
condenser, thus minimizing
air releases.
The condensed liquid per-
meate, containing highly
concentrated organic com-
pounds and significandy re-
duced in volume, generally
separates into aqueous and
organic phases, rendering the
organic fraction potentially
recoverable. The organic
phase permeate is pumped
from the containment vessel
to storage, while aqueous
phase permeate can either be
returned to the pervaporation
module for further treatment
or removed for disposal.
For more information, con-
tact Ron Turner at EPA's Na-
tional Risk Management Re-
search Laboratory at 513-569-
7775. Detailed information
on the technology's capabilities
and the results of the ZENON
SITE demonstration will be
discussed in the forthcoming
SITE Technology Capsule
(Document No. EPA/540/R-
95/51 la) and the Innovative
Technology Evaluation Report.
To get on the mailing list for
these documents, send a FAX
request to Ron Turner at 513-
569-7787.
MAILING LIST/ORDER INFO
To order additional copies of Ground Water Currents, or to be included on the permanent mailing fist, send a fax request to the National
Center for fnvtronnwsntal Pubficattons and information (NCEPQ at 51 ;M8$-86$5, or send a mail request to NCEPI, P,O, Box 424J? > Cincinnati, OH 45242-2419,
Please refer' to the document number on the cover of che issue if avaBabfe.
Gfound Water Currents welcomes readers' comments and contributions. Address correspondence to:
Crourxf Water Currents, NCEPI. P.O. Box 42419, Cincinnati, OH 45242-24{9,
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102W)
EPA-542-N-95-006
September 1995
Issue No. 13
Ground Water Currents
Developments in innovative ground water treatment
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