&EPA
United States
Environmental Protection
Agency
Office of
Research and Development
Cincinnati, OH 45268
EPA 540/R-94/522a
February 1995
SITE Technology Capsule
Dynaphore, Inc., Forager™
Sponge Technology
Introduction
In 1980, the U.S. Congress passed the Comprehen-
sive Environmental Response, Compensation, and Liabil-
ity Act (CERCLA), also known as Superfund, committed
to protecting human health and the environment from
uncontrolled hazardous wastes sites. CERCLA was
amended by the Superfund Amendments and Reautho-
rlzatlon Act (SARA) in 1986 - amendments that empha-
size the achievement of long-term effectiveness and
permanence of remedies at Superfund sites. SARA man-
dates Implementing permanent solutions and using al-
ternative treatment technologies or resource recovery
technologies, to the maximum extent possible, to clean
up hazardous waste sites.
State and federal agencies, as well as private par-
ties, are now exploring a growing number of innovative
technologies for treating hazardous wastes. The sites on
the National Priorities List total over 1,700 and comprise a
broad spectrum of physical, chemical, and environmen-
tal conditions requiring varying types of remediation. The
U.S. Environmental Protection Agency (EPA) has focused
on policy, technical, and informational issues related to
exploring and applying new remediation technologies
applicable to Superfund sites. One such initiative is EPA's
Superfund Innovative Technology Evaluation (SITE) pro-
gram, which was established to accelerate develop-
ment, demonstration, and use of innovative technologies
for site cleanups. EPA SITE Technology Capsules summa-
rize the latest information available on selected innova-
tive treatment and site remediation technologies and
related issues. These capsules are designed to help EPA
remedial project managers, EPA on-scene coordinators,
contractors, and other site cleanup managers under-
stand the types of data and site characteristics needed
to effectively evaluate a technology's applicability for
cleaning up Superfund sites.
This capsule provides information on the Dynaphore,
Inc. Forager™ Sponge technology, a technology devel-
oped to remove heavy metal contaminants from ground-
water, surface waters, and process waters. The Forager™
Sponge process was evaluated under EPA's SITE pro-
gram in April 1994, at the NL Industries, Inc. Superfund
Site In Pedricktown, NJ. The site was originally a second-
ary lead smelting facility. The groundwater at the facility
Is contaminated with heavy metals, including lead, cad-
mium, and chromium in excess of NJ groundwater stan-
dards. Information in the Capsule emphasizes specific
site characteristics and results of the SITE field demon-
stration at the NL Industries, Inc. site. This capsule pre-
sents the following information:
• Abstract
• Technology Description
• Technology Applicability
• Technology Limitations
• Process Residuals
• Site Requirements
• Performance Data
• Technology Status
• Source of Further Information
Abstract
The Forager™ Sponge is a volume reduction tech-
nology in which heavy metal contaminants from an
aqueous medium are selectively concentrated into a
smaller volume for facilitated disposal. The technology
treats contaminated groundwater, surface waters, and
process waters by absorbing dissolved ionic species onto
a sponge matrix. The sponge matrix can be directly
disposed, or regenerated with chemical solutions. The
Sponge can remove toxic heavy metals from waters in
the presence of high concentrations of innocuous, natu-
rally occurring dissolved inorganic species.
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Printed on Recycled Paper
-------
The Forager™ Sponge technology was demonstrated
under the SITE Program at the NL Industries, Inc. Superfund
site in Pedricktown, NJ. The mobile pump and treat sys-
tem treated groundwater contaminated with heavy met-
als. The demonstration focused on the system's ability to
remove lead, cadmium, chromium, and copper from the
contaminated groundwater over a continuous 72-hr test.
The results from the demonstration Indicated that cad-
mium was reduced by 90%, copper reduced by 97%,
lead reduced by 97%, and chromium reduced by 32%.
The removal of heavy metals proceeded in the presence
of significantly higher concentrations of innocuous cat-
ions such as calcium, magnesium, sodium, potassium,
and aluminum.
The Forager™ Sponge technology was easy to oper-
ate and exhibited no operational problems over the course
of the demonstration. The system is trailer-mounted, easily
transportable, and can be operational within a day upon
arrival at a site. The spent Sponge ccin be compacted
into a small volume for easy disposal.
The Forager™ Sponge technology was evaluated
based on the seven criteria used for decision making as
part of the Superfund Feasibility Study (FS) process. Results
of the evaluation are summarized in Table 1.
Technology Description
The Forager™ Sponge is an open-celled cellulose
sponge which contains a water-insoluble polyamlde
chelating polymer for the selective removal of heavy
metals. The polymer is intimately bonded to the cellulose
so as to minimize physical separation from the supporting
matrix. The functional groups in the polymer (i.e., amine
groups in the polymer backbone and pendent carboxyl
groups) provide selective affinity for heavy metals in both
cationic and anionic states, preferentially forming coordi-
nation complexes with transition-group heavy metals
(groups IB through VIIIB of the Periodic Table). The order
of affinity of the polymer for metals is influenced by solu-
tion parameters such as pH, temperature, and total ionic
content. The following affinity sequence for several repre-
sentative ions is generally expected by Dynaphore:
Al*
Au(CN)
> SeO -2
Ca+*> rv
AsO
n++ > Zn++> Ni
Hg++> CrO/2
> Co+
UO4'2
Ag+>
The high selectivity for heavy metals, and the low
selectivity for alkali and alkaline earth metals (Na+, K+,
Mg**, and Ca++), is especially useful for the treatment of
contaminated natural waters which may contain high
concentrations of these Innocuous chemical species. These
monovalent and divalent cations do not interfere with or
compete with absorption of heavy metals, therefore al-
lowing for maximum removal of heavy metals from con-
taminated waters.
The Sponge is highly porous which promotes high
rates of absorption of ions. Absorbed ions can be eluted
from the Sponge by techniques typically employed for
regeneration of ion exchange resins. Following elution,
the Sponge is ready for the next absorption cycle. The
useful life of the media depends on the operating envi-
ronment and the elution techniques used. Where regen-
eration is not desirable or economical, the Sponge can
be compacted to an extremely small volume to facilitate
Table 1. FS Criteria Evaluation for the Forager ™ Sponge Technology
FS Criteria
Overall Protection of
Human Health and
the Environment
Protects human health
and the environment
by removing
contaminants from
groundwater or
surface water.
Minimizes or
eliminates the
further spread of
contaminants within
the aquifer.
Compliance with
federal ARARs
Requires compliance
with RCRA treatment,
storage, and
disposal regulations
and pertinent
radioactive and
mixed waste
regulations.
Well construction
activities may
require permits.
Long-Ten n
Effectiveness and
Permanence
Permanently removes
contamination from
the affected
matrix.
Residuals fron i the
process must be
disposed of in an
appropriate
manner.
Reduction of Toxlcity, Short-Term
Mobility, or Volume Effectiveness
Through Treatment
Volume reduction Presents minimal
technology which risk to workers
transfers contam- and the
inants from community.
aqueous media
to a smaller
volume.
Ability to compact
Sponges to small
volumes may be
advantageous for
radioactive or mixed
waste.
Implementability
Easily implement-
able and trans-
portable.
Requires minimal
site preparation
and utilities
(water & elec-
tricity).
Cost
$340/1,000
gal with
regenerate
ion.
$238/1,000
gal with
Sponges
regener-
ated
twice pro-
viding for
3 useful
cycles.
Disposal of treated
waters may require
compliance with
Clean Water Act
and Safe Drinking
Water Act,
'Actual cost of a remedial technology Is site-specific and Is dependent on factors such as the cleanup level, contaminant concentrations and
types, waste characteristics, and volume necessary for treatment.
-------
disposal. The metal-saturated Sponge can also be Incin-
erated with careful attention given to the handling of
resultant vapors.
The Sponge can be used In columns, fishnet-type
enclosures, or rotating drums. For this demonstration, the
Sponge was utilized In a series of four columns. Each
column was comprised of a 1.7 ft3, pressurized acrylic
tube containing about 24,000 half-in. Sponge cubes con-
tained within a fishnet bag. The columns were mounted
on a mobile trailer unit.
Technology Applicability
The Forager™ Sponge Is capable of removing dis-
solved heavy metals from a wide variety of aqueous
media including groundwater, surface waters, landfill
leachate and industrial effluents. The chemistry employed
for metal removal is selective, allowing for the treatment
of toxic heavy metals in the presence of high concentra-
tions of innocuous cations, such as Ca++, Mg++, Na*, and
K+. The selective affinity of the polymer is similar to com-
mercially available selective chelating resins. However,
the Sponge's unique supporting cellulosic matrix may pro-
vide the technology with distinct advantages under cer-
tain processing conditions.
The Forager™ Sponge could be potentially Incorpo-
rated into varied treatment configurations. The technol-
ogy can be utilized in a conventional pump-and-treat
remedial process, as was performed during the SITE Dem-
onstration. The Sponge can be utilized as the primary or
secondary removal mechanism, dependent on the type
and concentration of contaminants, as well as the prop-
erties of the influent wastestream. For example, the Sponge
may be used as a polishing step in conjunction with a
technology that can remove high concentrations of met-
als to moderate levels (e.g., chemical precipitation). Ac-
cording to the developer, the Forager™ Sponge
technology can also be used in applications requiring In-
situ treatment. In these applications, the Sponge can be
placed into tubular fishnet containers and emplac€>d within
wells or trenches to intercept groundwater flow. The
Sponge can be used to treat surface waters by placing
the Sponge In a fishnet configuration across channels or
within other surface water bodies.
In addition, to potential different treatment applica-
tions, the Sponge's unique matrix provides advantages In
terms of disposal and operating conditions. The metal-
laden Sponge can also be compacted into small dis-
posal volumes, which could aid In lowering disposal costs,
and is beneficial where a minimum volume of residual
waste is needed due to the properties of the contami-
nants being absorbed. For example, this may be advan-
tageous in the treatment of radiologically contaminated
waters, where the need to minimize residual waste is a
critical disposal issue.
The high porosity of the Sponge enables a low pres-
sure system to be used. For this demonstration, the four
column unit operated under an inlet pressure as low as
4.4 psig. Although not demonstrated, if sufficient head
were provided, the system could have operated by grav-
ity flow.
Technology Limitations
The technology Is considered a volume reduction
technology since the contaminants are removed from
the waste stream and concentrated into a smaller vol-
ume which can be more easily handled and disposed.
The reduced volume, either sponge or acid regenerant
solution, must be immobilized by other means on-site or
off-site.
According to the developer, the scope of contami-
nants suitable for treatment using the Dynaphore Inc.
Forager™ Sponge Technology is limited to heavy metals.
The technology's affinity and absorption capacity for given
metals can vary and Is dependent on a number of waste
characteristics Including pH, concentration and types of
cations and anions present, and the presence of
complexing agents.
The technology usefulness may be limited by its over-
all absorption capacity for the heavy metals of concern.
If frequent changeout or regeneration of the columns is
required, it could make this technology cost prohibitive. In
these applications, pretreatment may be necessary in
order to reduce the concentration of specific contami-
nants to technically and/or economically optimal levels.
Process Residuals
The residuals generated from the Sponge technology
consist of either solid sponge material or liquid (acid)
regenerant solution. These residuals will be concentrated
with heavy metals, and depending on contaminant lev-
els, may be subject to RCRA regulations as a hazardous
waste. These waste materials can be easily stored in
appropriate 55-gal drums for off-site transport and dis-
posal. For the demonstration, four Sponges were hand
compacted into one 55-gal drum. Further compaction is
possible utilizing a waste compactor. Following comple-
tion of the demonstration, the developer sent four fishnet
bags of virgin Sponges to a waste compacting firm to
determine maximum compaction achievable. Tests per-
formed revealed compaction ratios of 4:1 and 10:1 utiliz-
ing compaction forces of 20,000 Ib and 85,000 Ib,
respectively.
Treated wastewater can be discharged to a Publicly
Owned Treatment Work (POTW), into surface waters, or
reinjected through underground injection wells, if appro-
priate discharge limitations are met and the proper per-
mits are obtained. For this demonstration, the treated
effluent was suitable for off-site treatment at a local POTW.
Site Requirements
The Forager™ Sponge treatment unit is mounted
on a flat bed trailer and is easily transportable. The four-
column trailer unit, measuring approximately 50 ft2, is
equipped with a water heater, wastewater pump, flow
-------
meter and totalizer. Once on site, the treatment system
can be operational within a day, if all necessary facilities,
utilities, and supplies are available. On-site assembly and
maintenance requirements are minimal.
Utilities required for the trailer unit are limited to water
and electricity. Electricity requirements are dependent
upon the need to pump the wastewater, if gravity feed is
not feasible, and the need to heat the wastewater to
improve absorption of metals. The wat€>r can be pumped
with the 12-V pump equipped on the trailer. This pump
can also run off a car battery, which was done for the
demonstration. The water heater requires a 220-V electri-
cal outlet. Water will be required occasionally for regen-
eration of the Sponges, cleanup and decontamination.
Support facilities include an area for untreated and
treated groundwater storage tanks (if used), a chemical
storage area for regenerant chemicals (i.e, acids) and
any other process chemicals, and a waste drum storage
area for spent Sponges, regenerant solutions, and other
wastes requiring disposal. These areas must be constructed
to control run-on and run-off. Additionally, an enclosed
building or shed may be necessary to protect equipment
and personnel from weather extremes. During the dem-
onstration, the treatment unit was housed in a tent. Mo-
bile office trailer(s) may also be needed on site.
Support equipment for the Forager™ Sponge Tech-
nology may include a drill rig for well installation, contain-
ers for waste storage, a forklift for moving waste drums,
and a waste compactor for compaction of Sponges. In
addition to an influent equalization tank, a treated stor-
age tank may be needed if the water can not be directly
discharged to a POTW or stream, or reinjected into the
ground.
Performance Data
The Forager™ Sponge Technology was evaluated for
its ability to remove heavy metals from groundwater.
Lead, cadmium, and chromium are contaminants of con-
cern at the NL site, and are frierefore the critical param-
eters for this study. In addition, copper was also consid-
ered a critical parameter because of the high removal
efficiency observed in predemonstration treatability tests.
The developer claimed that the technology would
achieve at least a 90% reduction of lead and copper, an
80% reduction in cadmium, and a 50% reduction of chro-
mium (as trivalent chrome) in the groundwater.
In addition to the primary objective, other secondary
(non-critical) objectives included:
• determine removal efficiencies for other heavy metals present
In txhe groundwater;
• determine removal efficiencies for critical parameters across
the four columns;
• evaluate the absorption capacity and regenerative capabili-
ties of the Sponge for the critical parameters;
• gather information to estimate operating costs, (e.g., utility
and labor requirements, waste disposal costs, treatment ca-
pacity, etc.).
The technology was evaluated over a continuous 72-
hr operational period, resulting In a total treatment vol-
ume of approximately 4,300 gal. Groundwater was
pumped from the Influent storage tank through the four-
column system at a treatment flow rate of 1 gpm or 0.08
bed volumes/min. The influent temperature was raised
approximately 15° C to increase reaction rates
(i.e.,improve absorption of the critical metals). The treated
effluent was initially discharged to a 250 gal portable tank
from which it was subsequently pumped to a 20,000 gal
effluent storage tank. The stored effluent was transported
off-site for treatment at a local POTW. A flow schematic
of the system is shown in Figure 1.
According to the developer, replacement or regen-
eration of the columns was not necessary, since none of
the columns were anticipated to become saturated (i.e.,
no further absorption capacity available for the critical
metals). Four columns were reportedly needed to provide
sufficient path length to meet the demonstration goals.
Groundwater
Well
SP4
Sponge
(C)
Sponge
(D)
Treated
Effluent
Tank
= Flow Meter/Totalizer Unit
Figure 1. Process flow diagram for the Dynaphore, Inc.. Forager™ Sponge demonstration.
-------
Although concentrations of some of the critical met-
als exceeded cleanup goals for the site, the ground water
was spiked with solutions of lead, copper, and cadmium
to assure effective evaluation (quantification) of the
developer's claim.
Grab samples for analysis of critical parameters were
collected from the raw influent, final effluent and Inter-
mediate column effluent points (see Figure 1). In addition,
equal volume 24-hr composite samples were collected
for total metals, chemical oxygen demand, total sus-
pended solids, total dissolved solids, sulfate, arid gross
alpha and gross beta radioactivity, Process measurements
for flow rate, total volume, pressure. pH, and temperature
were also monitored at these locations. Since the devel-
oper reported that replacement or regeneration of the
columns was not necessary, side tests on laboratory scale
columns treating standard metal salt solutions were per-
formed to aid in evaluating the absorption capacity and
regenerative capabilities of the Sp>onge.
Analytical results of critical parameters for the raw
influent and final effluent are presented in Table 2 and
depicted in Figure 2. These data show that treatment
claims for cadmium, copper, and lead were achieved.
The developer, however did not achieve treatment claims
for chromium. The treatment claim was based on com-
paring the mean concentration of the raw influent to the
mean concentration of the final effluent.
As shown in Figure 2, effective removal of chromium
(based on the 50% claim) was achieved within the first 10
hr of operation until performance markedly decreased.
The decrease in removal efficiency could be the result of
the Sponge's higher affinity for the other critical metals.
Although the cadmium claim was met based on the
overall effluent average, final effluent cadmium concen-
trations were below desired performance levels (107 ug/
L) at approximately the 61st hr of operation. This is due to
the lower than anticipated absorption capacity for cad-
mium which resulted in saturation of the first two columns
within the test period.
The technology had the greatest efficiency for cop-
per. One column was sufficient to meet the developer's
90% removal claim for approximately 53 hr of the 72-hr
test. Copper concentrations for columns 2,3, and 4, were
at or near detection limits throughout the demonstration
test. With regard to lead, three columns were sufficient to
meet the developer's 90% claim for approximately 61 hr
of the demonstration test.
Although claims for cadmium and lead were met,
some of the columns became saturated with these rnet-
als during the demonstration. Specifically, the first column
became saturated with both cadmium and lead, while
the second column became saturated with only cad-
mium. Saturation is defined when the effluent concentra-
tion of a given metal is approximately equal to or greater
than the Influent concentration. The first column was
saturated with both cadmium and lead at approximately
the 49th hr. Approximately 10 hr later, cadmium satu-
rated the second column. None of the columns were
saturated with copper during the demonstration test.
Based on a non-linear extrapolation of the data, the first
column would have become saturated with copper af-
ter approximately 4 days of continuous operation.
Based on data from the 72-hr demonstration, the
actual absorption capacity for the critical metals was
significantly lower (approximately 10 to 100 times lower)
than the developer's predemonstration estimates. These
estimates were based on absorption capacity tests on
standard metal salt solutions rather than the groundwa-
ter. The developer theorizes that anlon species such as
sulfate and phosphate may have interfered with the
effective removal of these metals. These results show the
need to conduct treatabillty tests on each wastestream
proposed for treatment to determine the true absorption
capacity of the system prior to implementing the tech-
nology.
Effective removal of cadmium, copper, and lead
was achieved in the presence of a groundwater pH
ranging from 3.1-3.8, a sulfate concentration of approxi-
mately 20,000 mg/L, a TDS concentration of approxi-
mately 23,000 mg/L, and disproportionately higher
concentrations of other cations such as magnesium (72
mg/L), potassium (82 mg/L), aluminum (149 mg/L), cal-
cium (224 mg/L), and sodium (6,000 mg/L).The
technology's low affinity for these cations was supported
by the near zero removal rates of these ions. Table 3
presents a summary of data for the non-critical heavy
metals.
In addition to the regeneration of the small test col-
umns, the developer conducted regeneration tests in his
laboratory on Sponge cubes taken from the demonstra-
tion columns. Both tests showed that regeneration Is fea-
sible for lead, copper, and cadmium. Regeneration of
chromium was evaluated only for the small test columns
and showed only partial regeneration.
The cost to treat heavy metal contaminated ground-
water over a one year period with the Dynaphore, Inc.
Forager™ Sponge Technology is estimated at $340/1,000
gal, assuming the Sponges are not regenerated and are
replaced upon saturation and $238/1,000 gal, assuming
the Sponges are regenerated twice providing for three
Table 2. Treatment Performance for Critical Metals
Parameter
Cadmium
Chromium
Copper
Lead
90% Confidence
Interval for
Avg. Influent
Cone. (ug/L
537 ± 11
426 ±31
917 ±14
578 ± 12
90% Confidence
Interval for
Avg. Effluent
Cone. (ug/L
56 ±13
290 + 30
25 + 0
18±3
90% Confidence
Interval for
Percent Removal
90 ±2.7
32 ±5.8
97 + .04
97 ±.59
Developer's
Treatment Claim
80
50
90
90
-------
i
I
1
O
5=
Uj
500
400
300
200
700
Cr(+3)
Cd
Cu
Pb
10 20 30 40 50
Elaps&d Time (hours)
60
70
D Cadmium
Chromium
O Copper
80
A, Lead
Figure 2. Final effluent - critical metals.
Table 3. Data Summary for Non-Critical Heavy Metals
Parameter
Avg. Influent Cone. (ug/L)
Avg. Effluent Cone. (ug/L)
Avg. Total % Removal
Aluminum
Arsenic
Barium
Beryllium
Calcium
Cobalt
Iron
Lithium
Magnesium
Manganese
Mercury
Nickel
Phosphorus
Potassium
Sodium
Strontium
Vanadium
Zinc
149,000
47.7
50.2
15.9
224,000
176
199,000
460
71,700
5870
0.39
378
1520
82,300
6,030,000
557
1310
1300
152,000
44.4
46.3
13.9
248,000
146
199,000
473
72,300
5880
0.21
107
557
83,700
6,130,000
562
53.2
1190
-2
7
8
13
-11
17
0
-3
-1
-1
46
72
63
-2
-2
-1
96
9
-------
useful treatment cycles. This cost estimate assumes ground-
water characteristics are similar to the demonstration
ground water and cadmium, lead, and copper are treated
to demonstration performance claims utilizing a four-col-
umn, pump-and-treat unit similar to the demonstration
unit. The system would operate 24 hr a day, 7 days a
week at a flow rate of 1 gpm resulting in a total treatment
volume of approximatley 525,000 gal.
A significant portion of the cost is attributable to the
frequent replacement or regeneration of the Sponges
due to the limited absorption capacity for cadmium in
this groundwater. The developer believes that a modifi-
cation of the polymer may Improve Its overall absorption
capacity for the critical metals which would greatly aid in
lowering treatment costs. Additionally, further cost reduc-
tion may be achieved through the use of larger scale
units which could handle higher flow rates (see below)
and the use of an industrial compactor to compact
Sponges to lower disposal costs.
Technology Status
To date, this SITE demonstration represents the first full-
scale use of this technology. The trailer mounted-unit was
built exclusively for this SITE Demonstration. This unit can
be modified to Include additional columns of the same
size. Additionally, a larger scale unit can also be con-
structed. This unit uses larger columns and would be just
as effective as the smaller system, but could operate at
approximately double the flow rate.
Dynaphore, Inc. has formed a liaison with a known
environmental remediation firm, Adtechs Corporation of
Herndon, VA, to provide the necessary expertise in per-
forming full-scale remediations at contaminated waste
sites.
Potential in-si1u applications, as previously discussed,
may be promising. However, insufficient data is currently
available which demonstrates the viability of this treat-
ment option. The effectiveness and cost of in-situ applica-
tions have not been evaluated in this study nor has the
developer commercially utilized the technology in these
applications. EPA is, however, planning to conduct a
second demonstration which will evaluate the technol-
ogy in an in-situ scenario.
Disclaimer
While the technology conclusions presented in this
report may not change, the data has not been reviewed
by the Quality Assurance/Quality Control Office.
Source of Further Information
EPA Contact:
U.S. EPA Project Manager
Carolyn Esposito
U.S. EPA, (MS-106)
2890 Woodbridge Avenue
Edison, NJ 08837
(908)906-6895
Technology Developer:
Norman Rainer
Dynaphore, Inc.
2709 Willard Road
Richmond, VA 23294
(804)288-7109
-------
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
Please make all necessary changes on the below label,
detach or copy, and return to the address in the upper
left-hand comer.
If you do not wish to receive these reports CHECK HERE D;
detach, or copy this cover, and return to the address in the
upper left-hand corner.
BULK RATE
POSTAGES FEES PAID
EPA
PERMIT No. G-35
EPA/540/R-94/522a
------- |