United States
Environmental Protection
Agency
EPA/540/MR-94/522
September 1994
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
Forager™ Sponge Technology
Dynaphore, Inc.
Technology Description: The Forager™ Sponge is an open-
celled cellulose sponge incorporating an amine-containing chelat-
ing polymer that has selective affinity for dissolved heavy metals
in both cationic and anionic states. The Forager™ Sponge tech-
nology can be utilized to remove and concentrate heavy metals
from a wide variety of contaminated aqueous media such as
groundwater, surface water, landfill leachate, and industrial efflu-
ents. The polymer preferentially forms coordination complexes
with ions of transition-group heavy metals by providing Ikjand
sites that surround the metal to form the complex. The order of
affinity of the polymer for metals is influenced by solution param-
eters such as pH, temperature, and total ionic content. The
following affinity sequence for several representative ions is gen-
erally expected by Dynaphore:
Ca+
The Sponge's ability to preferentially bind toxic heavy metals
over common aqueous constituents such as Na*. K*, Ca+*. and
Mg" is particularly beneficial for the treatment of contaminated
natural waters, which may contain high concentrations of these
innocuous chemical species. In conventional ion exchange or
precipitation technologies, valuable exchange sites or chemicals
are wasted by removing these innocuous ions. The Forager™
Sponge's low affinity for these cations allows these ions, for the
most part, to pass through the system, enabling absorption of the
toxic heavy metals.
The Sponge is highly porous, thereby promoting high rates of
absorption of ions. Absorbed ions can be eluted from the Sponge
Au(CN)2- > SeO4'2 > AsO4'3 > Hg" > CrO42 > Ag*
by techniques typically employed for regeneration of ion ex-
change resins. Following elution, the Sponge is ready for the next
absorption cycle. The useful life of the media depends on the
operating environment and the elution techniques used. Where
regeneration is not desirable or economical, the Sponge can be
compacted into an extremely small volume to facilitate disposal.
The metal-saturated Sponge can also be incinerated, 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 thousand 1/2 in.
Sponge cubes confined within a fishnet bag.
Waste Applicability: According to the developer, the Sponge
can scavenge metals in concentration levels of parts per million
(ppm) and parts per billion (ppb) from industrial discharges,
municipal sewage, process streams and acid mine drainage.
Demonstration Results: The Dynaphore Forager™ Sponge Tech-
nology was demonstrated at the NL Industries, Inc. site in
Pedricktown, N.J. between April 5 to 8, 1994. Heavy-metal con-
taminated groundwater was treated over a continuous 72-hr
operational period. Groundwater was pumped through a series of
four columns at a treatment flow-rate of 1 gpm or 0.08 bed
volumes/min. The columns were situated on a trailer-mounted
unit which included a water heater to raise the influent tempera-
ture by approximately 25°F to increase reaction rates. A flow
schematic of the system is shown in Figure 1. Four columns were
reportedly needed to provide sufficient path length to meet the
demonstration treatment goals.
Groundwater
.well
Raw
influent
tank
CSPI) (
Water
heater
(SP)
Sponge
(A)
SP2)
m Sampling point
[SP3
(SP4
SP5
oonge
(B)
Sponge
(C)
Sponge
(D)
< Flow meter/totalizer unit
Treated
effluent
tank
Figure 1. Process flow diagram for the Dynaphore, Inc. Forager™ Sponge demonstration.
Printed on Recycled Paper
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Based on field and laboratory treatabilfty tests, the developer
claimed that the technology would achieve at least a 90% reduc-
tion of lead and copper, an 80% reduction of cadmium and a 50%
reduction of chromium (as trivalent chrome) in the groundwater.
Although concentrations of some of these metals exceeded cleanup
goals for the site, the groundwater was spiked with solutions of
copper, cadmium and lead to allow for effective evaluation of the
developer's treatment claims. Treatment claims were evaluated
by comparing analytical data generated by raw influent and final
effluent grab samples. According to the developer, replacement or
regeneration 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 metals of concern).
Based on the preliminary results of the SITE demonstration, the
following conclusions were reached:
• Treatment claims for copper, cadmium, and lead were achieved.
The developer, however, did not achieve treatment claims for
chromium. Specifically, the performance was as follows:
Analyte
Average
Influent Conc.(ugTI)
Removal
Cadmium
Copper
Lead
Chromium*3
537
917
578
426
90
97
97
32
Effective removal of cadmium, copper, and lead was achieved
in spite of a groundwater pH ranging from 3.1 to 3.7, a sulfate
concentration of approximately 20,000 mg/l, and disproportion-
ately high concentrations of cations such as calcium, magne-
sium, aluminum, sodium, and potassium. Concentrations of
these cations ranged from 70 mg/l for magnesium, to 6000 mg/
I for sodium. The technology's low affinity for these cations was
supported by the low removal rates of these ions.
• Although treatment claims for cadmium and lead were met,
some of the columns became saturated with these metals
during the demonstration. Specifically, the first column became
saturated with both cadmium and lead, while the second
column became saturated with only cadmium. Saturation is
reached when the effluent concentration of a given metal is
approximately equal to the influent concentration. The total
capacity of the Sponge for these two metals was significantly
less than anticipated by the developer. The capacity for copper
was much greater, as none of the columns were saturated with
copper during the demonstration.
• Regarding disposal volume, four Sponge columns were hand
compacted into one 55-gal drum during the demonstration. The
developer has shipped four Sponge columns to a hazardous
waste compacting firm to determine maximum compaction
achievable for disposal.
An Innovative Technology Evaluation Report (ITER) describing
the complete demonstration will be available in early 1995.
For Further Information:
EPA Project Manager
Carolyn Esposrto
U.S. EPA, Building 10 (MS-106)
2890 Woodbridge Avenue
Edison, NJ 08837-3679
(908) 906-6895
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/540/MR-94/522
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