EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
EP/V540/5-90/005a
August 1990
Superfund
Emerging Technologies:
Bio-Recovery Systems
Removal and Recovery of
Metal Ions from
Groundwater
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EPA/540/5-90/005a
August 1990
Emerging Technologies:
Bio-Recovery Systems Removal and
Recovery of Metal Ions from Groundwater
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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DISCLAIMER
The information in this document has been funded in part by the United States
Environmental Protection Agency under Cooperative Agreement No. CR-815318010
to Bio-Recovery Systems, Inc. The document has been subjected to the Agency's
administrative and peer review and has been approved for publication as an EPA
document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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FOREWORD
The U.S. Environmental Protection Agency (EPA) is charged by Congress with
protecting the Nation's land, air, and water resources. As the enforcer of national
environmental laws, the EPA strives to balance human activities and the ability of natural
systems to support and nurture life. A key part of the EPA's effort is its research into our
environmental problems to find new and innovative solutions.
The Risk Reduction Engineering Laboratory (RREL) is responsible for planning,
implementing, and managing research, development, and demonstration programs to provide
an authoritative, defensible engineering basis in support of the policies, programs, and
regulations of the EPA with respect to drinking water, wastewater, pesticides, toxic
substances, solid and hazardous wastes, and Superfund-related activities. This publication
is one of the products of that research and provides a vital communication link between the
researcher and the user community.
Now in its fourth year, the Superfund Innovative Technology Evaluation (SITE)
Program is part of EPA's research into cleanup methods for hazardous waste sites around the
nation. Through cooperative agreements with developers, alternative or innovative
technologies are refined at the bench-and pilot-scale level and then demonstrated at actual
sites. EPA collects and evaluates extensive performance data on each technology to use in
remediation decision-making for hazardous waste sites.
This report documents the results of laboratory and pilot-scale field testing of dead,
immobilized algal cells in a silica gel polymer to remove heavy metal ions from mercury-
contaminated groundwaters. It is the first in a series of reports sponsored by the SITE
Emerging Technologies Program.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
iii
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ABSTRACT
A series of laboratory tests and an on-site pilot scale demonstration of Bio-Recovery
Systems' AlgaSORB® technology for the removal and recovery of mercury-contaminated
groundwaters were conducted under the SITE program.
Optimum conditions were determined for mercury binding to AlgaSORB®. Conditions
under which mercury could be stripped from AlgaSORB® were also developed.
On-site, pilot scale demonstrations with a portable waste treatment system
incorporating columns containing two different AlgaSORB® preparations confirmed
laboratory tests. Over 500 bed volumes of mercury-contaminated groundwater could be
successfully treated before regeneration of the system was required. Mercury was removed
to levels below the discharge limit of 10 u.g/L.
This report was submitted in fulfillment of Cooperative Agreement Number CR
815318010 by Bio-Recovery Systems, Inc. under the partial sponsorship of the U.S.
Environmental Protection Agency. This report covers a period from October, 1988 to
January 31,1990, and work was completed as of January 31, 1990.
iv
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TABLE OF CONTENTS
Page
Disclaimer :'.
Foreword '.'
Abstract IV
Figures v
Tables • i -v.
Acknowledgements v"
I. Executive Summary ^
II. Introduction. |
III. Conclusions and Recommendations • «*
IV. Background Information • j1
A. AlgaSORB® Description and Previous Work 4
1. Introduction 4
2. Waste Streams for Which the AlgaSORB® and Other Ion Exchange •
Technology Is Applicable 6
B. The Use of AlgaSORB® and Ion Exchange to Effect Heavy Metal Waste
Minimization: Comparison to Conventional Waste Treatment 6
C. State of Development 8
D. Application of AlgaSORB® to Metal-Contaminated Groundwaters and
Wastewaters ] 'P
1. Removal of Cadmium from Water at a Superfund Site 1 0
2. Removal of Copper from Contaminated Groundwaters Containing
Halogenated Hydrocarbons 1 °
3. Removal of Mercury from Contaminated Groundwaters.. 1 1
4. Selective Removal of Lead from Wastewaters - 1 1
V. Description of Site Containing Mercury Contaminated Groundwaters 1 3
VI. Laboratory Testing , • • • 1 j>
A. Experimental Procedures 1 5
B. Results • \ °
1. Water Analysis • 1 6
2 AlgaSORB® Tests 1 7
VII. On-Site, Pilot Scale Demonstration 30
VIII. Quality Assurance • 3^
A. Verification of Modification of EPA Method 245.1 for Mercury Analysis 35
B. Analysis of EPA-Provided Standard 36
C. Mercury Spikes • 3 ^
D. Mercury Analysis in the Presence of Thiosulfate 40
E. Analysis of Samples Resulting from On-Site Testing • 41
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LIST OF FIGURES
Number
1. Recycle-Recovery System 8
2. Automatic Recycle-Recovery 9
3. Portable Wastewater Treatment System Used for On-Site Testing...: 3 1
LIST OF TABLES
Number
1. Average Composition of Mercury-Containing Groundwaters ..13
2. Seasonal Variation of Mercury Concentration in Monitoring Wells 1 4
3. Mercury Concentration in Groundwaters 1 6
4. Analysis of Effluents from a Column Packed with AlgaSORB®-602 .1 7
5. Analysis of Stripping Effluents from Column Loaded in Table 4 1 8
6.. Analysis of Effluents from a Column Packed with AlgaSORB®-602 !l 8
7. Analysis of Effluents from a Column Packed with AlgaSORB®-602 1 9
8. Analysis of Effluents from a Column Packed with AlgaSORB®-602 20
9. Analysis of Stripping Effluents from Column Loaded in Table 8 !!."!.'.'20
10. Analysis of Effluents from a Column packed with AlgaSORB®-602 2 1
11. Analysis of Stripping Effluents from Column Loaded in Table 10 ..".'.....22
12. Analysis of Effluents from a Column Packed with AlgaSORB®-601 2 3
13. Analysis of Stripping Effluents from Column Loaded in Table 12........ 24
14. Analysis of Effluents from a Column Packed with AlgaSORB®-603 ..25
15. Analyses of Stripping Effluents from Column Loaded in Table 14 2 6
16. Analysis of Effluents from a Column Packed with AlgaSORB®-602 .......2 6
17. Analysis of Effluents from a Column Packed with AlgaSORB®-603 2 7
18. Analysis of Effluents from Two Columns in Series Packed with
AlgaSORB®-624 and AlgaSORB®-640 2 8
19. Analysis of Effluents from Two Columns in Series Packed with
AlgaSORB®-624 and AlgaSORB®-640 2 9
20. Variation in Mercury Content of Groundwaters During On-Site Pilot
Scale Testing 32
21. On-Site Pilot Testing for Mercury Removal from Groundwaters .....33
22. Analysis of Effluents from AlgaSORB®-624 Column on the Portable
Treatment System 34
23. Mercury Analysis of Standards Using Sodium Borohydride as a Reductant .".35
24. Mercury Analysis of Standards Using Sodium Borohydride as a Reductant :....3 6
25. EPA-Provided Sample Information 37
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26. Mercury Analysis of EPA Water Pollution Quality Control Sample 38
27. Error and Recovery Analysis of Mercury Spikes • 39
28. Effect of Thiosulfate on Mercury Analysis • 40
29. Analysis of Mercury-Thiosulfate Samples Oxidized with Hydrogen Peroxide 40
30. Mercury Analyses of Thiosulfate-Containing Solutions Without Acid Digestion 41
31. Identification of Samples Sent to Woodward-Clyde Consultants and EER
Technologies for Mercury Analysis.. ..;.....,.. 4 2
vii
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ACKNOWLEDGEMENTS
This document was prepared under Cooperative Agreement No. CR 815318010 by
Bio-Recovery Systems, Inc., Las Cruces, NM under the sponsorship of the U. S.
Environmental Protection Agency. Naomi P. Barkley of the Risk Reduction Engineering
Laboratory, Cincinnati, Ohio was the Project Officer responsible for the preparation of this
document and deserves special thanks for her helpful comments and advice. Special
acknowledgement is given to Donald E. Sanning, Chief, Emerging Technology Section, SITE
Demonstration and Evaluation Branch, Superfund Technology Demonstration Division for
providing technical guidance and input.
Participating in the development of this report for Bio-Recovery Systems, Inc. were
Dr. Dennis W. Darnall and Michael Hosea. Special recognition is given to Sandy Svec, Dr.
Maria Alvarez, Rafael Tamez and David Marrs for laboratory and on-site pilot testing and
coordination of analysis.
viii
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I. EXECUTIVE SUMMARY
During 1989 laboratory and on-site pilot scale testing of Bio-Recovery Systems'
AlgaSORB® technology for the removal and recovery of mercury from contaminated
groundwaters were conducted. AlgaSORB®, a non-living, immobilized algal bio-mass, was
packed into columns through which the mercury-contaminated groundwaters were pumped.
Mercury concentrations in influent and effluent were measured to determine the
effectiveness of mercury removal. Once the columns showed unacceptable mercury leakage
(10 u,g/L), the columns were stripped of mercury and reused.
Several different AlgaSORB® preparations containing different algal species were
tested for effectiveness in mercury removal.
Summary Results
AlgaSORB® testing was complicated by the fact that over the sampling period mercury
concentrations in the groundwaters varied by over an order of magnitude from 150 u.g/L to
1550
In addition it was found that one variety of AlgaSORB® showed varied mercury-
binding capability with waters collected at various times. This suggested a variation in
mercury speciation over the sampling period. Because of these variations, final on-site
pilot scale testing was done with a blend of two AlgaSORB® preparations. One preparation
had a rather high mercury capacity but also exhibited a rather high leakage of mercury and
the second preparation had a lower mercury binding capacity but exhibited low leakage of
mercury.
On-site, pilot scale testing was conducted November 7 to December 1, 1989. A
portable water treatment system that contained columns of the two different AlgaSORB®
preparations was tested over the three week period. Waters were pumped through the
AlgaSORB® resins at a flow rate of 6 bed volumes per hour. Over 500 bed volumes of
mercury contaminated waters were passed through the resins before effluent mercury
concentration exceeded discharge levels of 1.0 |xg/L. These results suggest that a full-scale
treatment system would be effective for mercury removal from groundwaters. Costs
associated with such a treatment system should be typical of those associated with
commercial ion exchange systems for treatment of industrial waste waters. In contrast to
commercial ion exchange resins, however, AlgaSORB® functions well with waters which
have a high total dissolved solid content and which contain organic compounds.
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II. INTRODUCTION
The Superfund Amendments and Reauthorization Act of 1986 (SARA) directed the
Environmental Protection Agency (EPA) to establish an "Alternative or Innovative
Treatment Technology Research and Demonstration Program." In response, the EPA's Office
of Solid Waste and Emergency Response and the Office of Research and Development
established a formal program called the Superfund Innovative Technology Evaluation (SITE)
Program, to accelerate the development and use of innovative cleanup technologies at
hazardous waste sites across the country.
The SITE Program is comprised of the following five component programs:
Demonstration Program
Emerging Technologies Program
Measurement and Monitoring Technologies Development Program
Innovative Technologies Program
Technology Transfer Program
This report is the first in a series of reports sponsored by the SITE Emerging
Technologies Program. Before a technology can be accepted into the Emerging Technology
Program, sufficient data must be available to validate its basic concepts. The technology is
then subjected to a combination of bench- and pilot-scale testing in an attempt to apply the
concept under controlled conditions.
Bench- and pilot-scale testing of the Bio-Recovery Systems, Inc. AlgaSORB®
technology has been performed under the SITE Emerging Technology Program. The
AlgaSORB® technology is designed to remove heavy metals from aqueous solution. The
process is based upon the natural affinity of algae cell walls for heavy metal ions. The
sorption medium, AlgaSORB®, is composed of a non-living algal bio-mass which is
immobilized in a silica polymer. AlgaSORB® is a hard material which can be packed into
columns which, when pressurized, exhibit good flow characteristics. This technology is
useful for removing heavy metal ions from groundwaters that contain high levels of
dissolved solids.
Groundwater contamination is found at over 70 percent of the sites currently on the
National Priority List (1). Groundwaters have been contaminated with either, or both,
toxic organic molecules and heavy metal ions. The most common means of addressing
contaminated groundwater is extraction and treatment. While biological in situ treatment
of groundwaters contaminated with organics may be possible, there is no effective method
for in situ treatment of groundwaters contaminated with heavy metals. AlgaSORB® was
developed for removal of dilute concentrations of heavy metals from groundwaters. ;
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III. CONCLUSIONS AND RECOMMENDATIONS
A, Conclusions:
On-site, pilot scale testing of AlgaSORB® showed effective mercury recovery from
contaminated groundwaters. However, initial laboratory experiments showed the,' dangers in
making conclusions from a single groundwater sample. These studies showed that not only
did mercury concentration vary over the sampling period, but also the data suggested that
the chemical species of mercury varied over the sampling period as well. In the end it was
found possible to combine two different AlgaSORB® preparations to effect mercury removal
from groundwaters to levels below 10 u.g/L.
B.
Recommendations:
Work done at the site described herein indicates that a full treatment system for
mercury recovery can be installed. However, because the chemistry of other groundwater
sites will undoubtedly differ from the one tested here, laboratory treatability testing will be
required before the technology can be applied at other mercury-contaminated groundwater
sites.
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IV. BACKGROUND INFORMATION
A. AlgaSORB® Description and Previous Work
1. Introduction ,
The use of microorganisms in the treatment of hazardous wastes containing both
inorganic and organic pollutants is becoming more and more common. There have been two
approaches to the use of microorganisms in .waste treatment. One involves the use of living
organisms and the other involves the use of non-viable biomass derived from
microorganisms. While the use of living organisms is often successful in the treatment of
toxic organic contaminants, living organisms have not been found to be useful in the
treatment of solutions containing heavy metal ions. This is because once the metal ion
concentration becomes too high or sufficient metal ions are adsorbed by the microorganism,
metabolism is disrupted causing the organism to die. This disadvantage is not encountered if
non-living organisms or biological materials derived from microorganisms are used to
adsorb metal ions from solution. Instead the biomass is treated as another reagent, a
surrogate ion exchange resin. The binding, or biosorption, of metal ions by the biomass
results from coordination of the metal ions to various functional groups in or on the cell.
These chelating groups, contributed by the cell biopolymers, include carboxyl, imidazole,
sulfhydryl, amino, phosphate, sulfate, thioether, phenol, carbonyl, amide and hydroxyl
moieties (2).
Various algal species and cell preparations have quite different affinities for different
metal ions (3-4). The different and unusual metal binding properties exhibited by different
algae species are explained by the fact that various genera of algae have different cell wall
compositions. Thus, certain algal species may be much more effective and selective than
others for removing particular metal ions from aqueous solution (5).
The reaction of heavy metal ions with a non-living algal qell forms complexes which
are composed of the algal cell and the metal ions. The result of this reaction, i.e., the
formation of the alga-metal ion complex is basically why metal ions are toxic to living
organisms and explains how the toxic effect of metal ions is amplified in the food chain. The
metal ions are adsorbed to the cell even at concentrations in the mg/L-u.g/L range. The
bound metal ions, when accumulated over time, eventually interfere with metabolism by
disruption of enzyme reactions and kill the organism. If microorganisms on which metal
ions have been sorbed are used as a food source by larger organisms, the metal ions find
their way into the food chain which can eventually result in toxic effects for humans.
While the interaction of metal ions with microorganisms has been known for many
years, it is only recently that advantage has been taken of the high affinity of microorganism
cell walls to remove and recover metal ions from industrial wastewater or contaminated
groundwaters. Methods to reverse the reaction of metaj ion sorption have been developed so
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that when metal ions are recovered from dilute solutions they can be stripped off the cell
walls in a highly concentrated form. The cells can then be reused to capture more metal ions
from dilute solutions. Conditions can also be adjusted so that only one or two types of metal
ions are adsorbed from a solution containing several metal ions, or a variety of metal ions
can be sorbed from solution and then they can be selectively stripped from the algal cell one
metal at a time (2,6).
Bio-Recovery Systems, Inc. has developed a proprietary, algal based material,
AlgaSORB®, which can be used on a commercial basis to remove and recover heavy metal ions
from point-source industrial wastewater, contaminated groundwaters or mining process
streams. AlgaSORB® functions very much like a commercial ion exchange resin. It can be
packed into columns through which waters containing heavy metal ions are flushed. The
heavy metal ions are adsorbed to AlgaSORB® and metal-free water exits the column for reuse
or discharge. Once the AlgaSORB® is saturated with metal ions, the metals can be stripped
from the AlgaSORB® which is then ready for reuse. In comparison to ion exchange resins,
however, AlgaSORB® has some distinct advantages which make it superior to ion exchange
resins for certain applications (see below). In other instances ion exchange resins perform
better than AlgaSORB®. AlgaSORB® has a remarkable affinity for heavy metal ions; in some
cases the metal-binding capacity is as much as 10 percent of the dry weight of the cells. The
algae matrix is capable of concentrating heavy metal ions by a factor of many thousand-fold.
When unadulterated algal cells are packed into columns, the cells tend to aggregate and
to form cohesive clumps through which it is difficult to force water even under high
pressures. However, when the cells are immobilized into a polymeric matrix, this
difficulty is alleviated.
The algae are killed in the immobilization process indicating that sorption does not
require a living organism, and hence the algal matrix can be exposed, with little or no ill
effects, to solution conditions which would normally kill living cells. The pores of the
polymer are large enough to allow free diffusion of ions to the algal cells, since similar
quantities of metal ions are bound by free and immobilized cells. The immobilization
process serves two purposes: (I) It protects the alga cells from decomposition by other
microorganisms, (AlgaSORB® immersed in aqueous solution for over two years has shown no
decrease in metal binding efficiency) and (2) it produces a hard material which can be
packed into chromatbgraphic columns, pressurized and exhibits excellent- flow
characteristics.
In addition to the immobilized algal matrix's usefulness for the removal of the
"traditional" heavy metals from solution, it also is useful for near quantitative removal and
recovery of very low concentrations (in the parts per billion range) of precious metals s'uch
as gold, silver, platinum and palladium (7).
AlgaSORB® functions as a "biological" ion exchange resin and like other ion-exchange
resins, can be recycled. Metal ions have been sorbed and stripped over many cycles with no
noticeable loss in efficiency. In contrast to current ion exchange technology, however, a real
advantage of the algal matrix is that the components of hard water (Ca+2 and Mg+2) or
monovalent cations (Na+ and K+) do not significantly interfere with the binding of toxic,
heavy metal ions. In fact calcium or magnesium ion concentrations as high as 10,000 mg/L
have little or no effect on AlgaSORB® sorption of copper at concentrations as low as 6.5
mg/L. The binding of Ca+2 and Mg+2 to ion-exchange resins (even chelating ion exchange
resins which are relatively selective for transition metal ions) often limits ion exchange
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usefulness since calcium and magnesium ions are frequently present in high concentrations
and compete with heavy metal ion binding. This means that frequent regeneration of ion-
exchange resins is necessary in order to effectively remove heavy metal ions from solutions.
AlgaSORB® is also effective for heavy metal removal from waters containing organic
residues. Organics often foul synthetic ion exchange resins which limits their utility in
many wastewater treatment applications, including groundwater treatments. AlgaSORB®, on
the other hand, functions well in waters containing organic molecules.
2. Waste Streams for which the AlgaSORB® and Other Ion Exchange Technology is
Applicable
A major source of heavy metal wastes from industrial sources comes from the
electroplating, metal finishing and printed circuit board manufacturing industries.
Wastewaters from these industries primarily come from rinsing operations. The
rinsewaters will typically contain rather low concentrations (on the order of 100 parts per
million) of heavy metal ions. Certain of these waste streams are particularly amenable to
treatment with AlgaSORB® or ion exchange resins. The metals can be recovered and then
either recycled back into the process or recovered for use by other industries. In addition
AlgaSORB® may be useful for polishing waste streams previously treated by other methods,
but which still have metal ions present at concentrations above compliance levels.
Contaminated groundwaters and surface leachates often contain heavy metals in the low
parts per million or even part per billion range. The AlgaSORB® technology is well suited
for removing and recovering heavy metal ions from these waters, which will often contain
high concentrations of dissolved materials which are non-toxic. Often these types of waters
will contain high concentrations of sodium, potassium, calcium, magnesium, chloride or
sulfate which are innocuous and for which no treatment is needed. AlgaSORB® is capable of
preferentially removing heavy metals which are found in these streams. Toxic heavy metal
ions which can be recovered with the algal biomass include copper, nickel, uranium, lead,
mercury, cadmium, zinc, arsenic and silver among others.
AlgaSORB® has a higher affinity for precious metal ions than any other heavy metal
ions tested (5-6). Thus another area in which the AlgaSORB® technology is useful is in the
recovery of gold, silver or platinum group metals from mining process streams,
wastewaters resulting from mining operations, and industrial point source wastewater.
B. The Use of AlgaSORB® and Ion Exchange to Effect Heavy Metal Waste Minimization:
Comparison to Conventional Waste Treatment
The conventional method for treating wastewaters in electroplating or printed circuit
board manufacturing plants has been to commingle all metal-containing wastewaters which
are then sent to a central location for treatment. Treatment methods vary depending upon
what metals are present in the stream, but the most common treatment is precipitation of
the metals as hydroxides. If metal cyanide complexes are present, cyanide is usually
oxidized prior to metal precipitation. Likewise, if hexavalent chromium is present, it is
usually reduced to trivalent chromium prior to precipitation. The metal hydroxide
precipitates are then dewatered and most commonly sent to a hazardous waste landfill. Since
August 8, 1988, these metal-containing sludges can no longer be sent to a hazardous waste
landfill unless they are stabilized so that the toxic metal ions cannot be leached from the
sludge. A variety of agents such as Portland cement, fly ash or other pozzolanic materials
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can be used to stabilize the sludge, but whatever the stabilization method, the disposal costs
have increased dramatically since August 1988. In addition both state and federal regulatory
agencies are moving toward the future complete ban of land disposal of metal hydroxide
sludges in any form.
In addition to high sludge disposal cost, another disadvantage of the conventional
treatment system is the difficulty in many instances of reaching effluent metal
concentrations low enough to meet discharge standards. This is because hard-to-treat
waters are often commingled with easy-to-treat waters thereby making all the wastewater
hard-to-treat. For example, in printed circuit board manufacturing operations there are
typically three different types of copper-bearing wastewaters which must be treated:
copper sulfate from acid copper baths, ammoniacal copper from alkaline etchers and
chelated (usually EDTA, quadrol or tartrate) copper from electroless copper baths. Copper
sulfate responds very well to hydroxide precipitation, but the ammonia complex of copper
and the EDTA chelate of copper are very difficult to treat with conventional hydroxide
precipitation. Thus expensive chemicals such as sodium borohydride or dithiocarbamates
are added to the entire wastewater stream in order to treat the ammoniacal and chelated
copper which usually make up only a small proportion of the total waste streams.
When the conventional hydroxide precipitation of metals is used, usually sodium
hydroxide or lime along with other reducing agents or flocculating agents are added to
produce the metal hydroxide sludge. Once the sludge is removed from the wastewater the
water is generally discharged to a sewer. There is no opportunity for reuse or even partial
reuse of the water because the effluent water has too many dissolved salts to be effective as a
rinsewater. The cost of deionizing this water is generally much higher than the cost of
deionizing fresh tap water and hence water reuse is generally not a viable economic option.
Generators of toxic metal sludges are held liable, without proof of fault, for cleaning
costs and natural resource damage at hazardous waste disposal sites at which the generator's
waste is disposed. Therefore if the owners of a hazardous waste dump happen to mismanage
the site so that toxics are allowed into the environment, it is the generator who is ultimately
responsible for clean-up. Thus any process by which sludge can be minimized or eliminated
will reduce liability for the generator.
Bio-Recovery Systems' technology has been incorporated into an effective recovery-
recycle approach to wastewater treatment for the electroplating, metal finishing and
electronics industries. The concept is illustrated in Figure 1 for a treatment system that
allows for recovery of metals and recycling of process waters. In this scheme rinsewaters
derived from each individual plating bath are segregated and passed through columns
containing AlgaSORB® or specialty ion exchange resins. Metal ions are removed from the
rinsewaters which can then be discharged directly or returned to the rinse tanks for partial
water reuse. Because salts tend to build-up in the rinsewaters, deionization of the
treatment effluent may be needed if it is to be reused in critical rinses. Otherwise a bleed-
off of water to the sewer is adequate to keep salt-build up at acceptable levels. Such an
approach can often decrease water usage by 50 to 90 percent.
Once the columns of ion exchange resins or AlgaSORB® are saturated with metals, the
metal ions can be stripped from the columns. The concentration of the stripped metals is
approximately 10 g/L. In certain instances these stripped metal ions can be added back to
the plating bath. In instances where this is not acceptable, the metal can be recovered
through electrowinning or metalwinning. Alternatively the metal ions can be further
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concentrated by evaporation and sent to one of a number of companies which are now
established to recycle such materials. Whichever approach is taken, however, the
elimination of sludge production results in lower operational costs due to decrease in
chemical costs, decrease in water usage, elimination of sludge disposal costs and
minimization of future liability.
RECYCLE-RECOVERY SYSTEM
WORK
PLATING
TANK
/-^ JL
jr _x_^»_x-tx>
RINSE
TANK
RINSE
TANK
•~l
CONCENTRATE
PURIFIED
WATER
Figure 1. Recycle-Recovery System. Segregated rinsewaters from a plating process
are directed through a recovery system where metal ions are recovered, and the
rinsewaters are directed back to the rinse tanks. The concentrated recovered metals are
sent back to the plating process tank where possible.
C. State of Development
Bio-Recovery Systems is currently manufacturing arid installing wastewater
treatment systems for use in recovering heavy metals from industrial point sources in the
electroplating and printed circuit board manufacturing industries. Figure 2 shows one such
system which has been designed for a printed circuit board manufacturer. The heart of the
system is comprised of columns (B) which contain the metal-adsorbing materials.
Rinsewaters which contain only a single type of plating or etching chemistry are segregated
and plumbed to individual columns. When the columns become saturated with metal ions, a
specific metal ion sensor signals the controller (A) to begin a regeneration cycle to strip the
metals from the materials in the column and to send the stripped metal ions to one of the
holding tanks (D). Once regeneration is complete, the controller automatically returns the
regenerated column back into service. The stripped metals are then recovered as the
metallic elements in the metaiwinning unit (E).
The system shown in Figure 2 is capable of treating 30 L/min (8 gal/min), however
larger flow rates (up to hundreds of gallons per minute) are accommodated by simply adding
either more metal-adsorbing columns or by using larger diameter columns.
The system shown in Figure 2 was designed for a printed circuit board
manufacturer, but the same1 type of system is also employed for metal finishing and
electroplating facilities.
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c
B
Figure 2. An Automatic Recycle-Recovery Wastewater Treatment System. A. controller.
B. metal adsorbing modules. C. deionized water system/ D. holding tanks for pH adjustment,
regenerant chemicals. E. metalwinning module.
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Different chemistries are encountered in metal finishing rinsewaters, but the approach to
treatment of these waters is basically the same as that encountered in a printed circuit board
manufacturer's facility, i.e., wastewaters are segregated for treatment so that maximum
reuse, of metals and water can occur.
D. Application of AlgaSORB® to Metal-Contaminated Groundwaters and Wastewaters
In 1986 and 1987 Bio-Recovery Systems was awarded Small Business Innovative
Research (SBIR) contracts from the United States Environmental Protection Agency (EPA)
to research and develop the AlgaSORB® technology for commercial applications. Results from
these contracts, some of which are summarized below, show the efficiency of AlgaSORB® for
heavy metal removal from a variety of sources. These successful laboratory tests led to
Bio-Recovery's participation in the SITE program, through submission of a pre-proposal to
the Emerging Technology Program.
1. Removal of Cadmium from Waters at a Superfund Site
Officials from EPA Region II arranged to supply samples from a well at a Superfund
site in New Jersey, the Waldick Aerospace Devices site. These waters were contaminated
with cadmium at a level of 0.13 mg/L. The waters at a pH of 6.0-7.1 also contained, among
other organics, 0.66 mg/L of a halogenated hydrocarbon, tetrachloroethylene.
A column containing AlgaSORB® (0.7 cm i.d. x 13 cm high) was prepared, and the
Waldick Aerospace waters were passed through the column. Five mL fractions of water
exiting the column were collected until 500 mL (100 bed volumes) of Waldick waters were
passed through the column at a flow rate of one-sixth of a bed volume per minute (total bed
volume was 5.0 mL). Each fraction of effluent was analyzed for cadmium using graphite
furnace atomic absorption spectrometry. All effluent fractions showed that cadmium
concentration was near or below 0.001 mg/L after the passage of the 100 bed volumes of the
cadmium-containing solution. Because the experiment was stopped after the passage of 100
bed volumes through the column, it is not possible to state explicitly what volume of solution
could be treated before cadmium breakthrough would occur. However, experience has shown
that if a test material is capable of treating at least 100 bed volumes of metal-bearing
water, use of that material is economically feasible. The essential point is that AlgaSORB®
removed cadmium well below those levels which are allowed in drinking water. The current
drinking water levels for cadmium stand at 0.005 mg/L.
After 100 bed volumes of the cadmium-containing solution had passed through the
AlgaSORB®-containing column, cadmium was stripped from the column by passing 0.15M
H2SO4 through the column. Analysis of the column effluents showed that nearly 90 percent
of the cadmium was stripped from the column with the passage of two bed volumes of
sulfuric acid Jhrough the column. Most of the remainder of the cadmium appeared in the
next two bed volumes. Mass balance calculations showed that, within experimental error,
all of the bound-cadmium was stripped from the column.
2. Removal of Copper from Contaminated Groundwaters Containing Halogenated
Hydrocarbons
Bio-Recovery Systems obtained groundwaters which had been contaminated with
copper, tetrachloroethylene and dichloroethylene by a printed circuit board manufacturer.
These waters contained a total dissolved solid content (TDS) of nearly 2000 ppm and had a
10
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total calcium and magnesium content of approximately 300 ppm. Past experience had shown
that ion exchange resins were not effective in treating these waters for copper removal
because of i) the high mineral content and ii) the propensity of the resins to become clogged
with the organics in these waters. However, experiments showed that 400 bed volumes of
the copper containing waters could be passed through a column (0.7 cm i.d. x 13 cm high)
containing AlgaSORB® without effluents from the column containing more than 0.01 ppm of
copper. The experiments were stopped at 400 bed volumes, so undoubtedly larger volumes
of waters could have been treated before unacceptable levels of copper appeared in the
effluents.
After 400 bed volumes had been passed through the AlgaSORB® column, the bound
copper was, within experimental error, completely stripped from the column by passing
0.5M H2SO4 through the column. Again, as with the previously described cadmium
stripping, the copper was almost completely stripped within the first few bed volumes of
eluent.
3. Removal of Mercury from Contaminated Groundwaters
Bio-Recovery was provided with water samples from a mercury-contaminated
groundwater site. The site had been contaminated with mercury years ago as a result of a
process used to manufacture chlorine from seawater. The groundwaters contained 2-3 ppm
of mercury (both inorganic and organic mercury), had a total dissolved solid content of
7,200 mg/L and contained over 900 mg/L of calcium and magnesium. Passage of these
mercury-containing waters through an AlgaSORB® column (0.7 cm i.d. x 13 cm high)
resulted in effluents which contained mercury at levels below 0.006 mg/L as determined by
analysis using cold vapor generation and atomic absorption spectrometry. The customer
requires effluents of below 0.01 mg/L for discharge.
These experiments show, as had earlier experiments, that AlgaSORB® is effective in
removing both inorganic and organic mercury from aqueous solutions even in the presence of
very high concentrations of calcium, magnesium and other dissolved salts.
4. Selective Removal of Lead from Wastewaters
The printed circuit board industry frequently plates a tin-lead alloy onto printed
circuit boards as a base for solder connections. The tin-lead alloy is plated from a solder
bath which often contains tin and lead fluoborates. Since tin discharge is not currently
federally regulated, the major problem in treating rinsewaters derived from tin-lead solder
baths is lead removal. One particular AlgaSORB® preparation is especially amenable for this
application since it strongly binds lead and allows the majority of the tin to pass through.
A sample of a tin-lead plating bath was obtained from a printed circuit board
manufacturer. The bath composition included lead fluoborate, stannous fluoborate, boric
acid and peptone. The bath rinsewaters commonly contain 10-60 mg/L of lead and about
twice as much tin.
A column containing AlgaSORB® (3.3 mL total bed volume) was prepared and the tin-
lead containing waters (27.4 mg/L of lead; 49 mg/L of tin) which had first been adjusted to
pH 5.0 were passed through the column at a flow rate of one-third of a bed volume per
minute. Two-bed volume fractions of the effluent were collected, and each of these fractions
was analyzed for tin and lead by atomic absorption techniques. All effluent fractions showed
11
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lead concentrations at or below the detection limit of 0.1 mg/L for the first 300 bed
volumes, after which lead began to appear in the effluents. Influent tin-lead passage was
stopped after passage of 325 bed volumes through the column after which the column was
stripped of lead by elution with 0.5M nitric acid (8).
All fractions eluted through the AlgaSORB® column were also analyzed for tin. Because
tin is more weakly bound than lead, tin began to exit the column after passage of only 33 bed
volumes of influent. Thus the AlgaSORB® column showed marked preference for lead over
tin. When the column was stripped of lead (after 325 bed volumes) the small amount of tin
bound on the column was also fully recovered in the nitric acid stripping solution (8).
12
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V. DESCRIPTION OF SITE CONTAINING MERCURY-CONTAMINATED GROUNDWATERS
A number of years ago an industrial process using mercury resulted in soil
contamination with elemental mercury. The mercury subsequently percolated through the
soils and contaminated groundwater. At some point the mercury was oxidized to the bivalent
oxidation state and was found at various concentrations in the groundwaters depending upon
the monitoring site. Currently, the groundwaters are extracted from an upper perched
groundwater table via a drainage gallery. A facility has been constructed to treat extracted
groundwaters by the use of precipitation with dithiocarbamates, followed by polishing with
activated carbon and a specialty ion exchange resin. The water is pumped from the gallery at
mercury concentrations of 0.1-3.0 ppm and is currently treated to allowable discharge
limits of 10 ppb mercury.
Wells monitoring the groundwater during the late 1980's showed seasonal variations
in the mercury concentrations. It appears that mercury levels decrease in the dry seasons
compared to the rainy season. Chemical speciation of the mercury in the groundwaters was
not rigorously determined, but speciation studies on soils overlying the groundwater
indicated the predominant species was oxidized inorganic mercury. The composition of other
elements in the groundwater seems to change with the seasons as well, but an average
composition is given in Table 1. Variations in mercury content over a four year monitoring
period in waters from two wells, about 150 feet from one another, are shown in Table 2.
;
TABLE 1. AVERAGE COMPOSITION OF MERCURY-CONTAINING GROUNDWATERS
Constituent
Concentrations (ma/L)
Chloride
Sodium
Calcium
Magnesium
Total Dissolved Solids
PH
5,800
2,900
460
440
11,000
8.0
Several hypotheses concerning mercury speciation in the groundwaters were
considered by other contractors in the mid-1980's. Based upon available groundwater
chemistry data and the presence of high chloride ion concentrations, it was considered likely
that the predominant dissolved inorganic forms of mercury included chloride complexes.
They were thought to vary from HgCI+ through HgCU"2- Uncomplexed ionic mercury could
be either divalent or monovalent.
13
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TABLE 2. SEASONAL VARIATION OF MERCURY CONCENTRATION IN MONITORING WELLS
Month/Yr
Oct/1
Nov/1
Dec/1
Jan/2
Mar/2
Apr/2
May/2
Sep/2
Dec/2
Feb/3
Sep/3
Dec/3
Apr/4
May/4
Jun/4
Aug/4
Sep/4
Oct/4
Well 1
(mtf/L)
9.60
3.35
0.29
5.50
3.80
10.00
4.20
7.70
6.10
6.20
8.50
2.70
4.00
4.00
4.40
5.80
7.70
13.00
Well 2
(mg/L)
0.370
0.293
0.426
0.230
0.390
0.200
0.300
0.370
0.510
0.500
0.240
0.140
-
0.260
0.170
0.180
0.086
0.240
Furthermore, with many different anions present in the water, inorganic mercury could be
present in a variety of complexed forms.
It was also established in the mid-1980's that the groundwaters contained
significant quantities of organic compounds. It is therefore possible that some of the
mercury in the groundwater could also be in the form of organo-mercury complexes. Less
than one percent of the mercury present in soils at the site was found to be organo-mercury.
However for an aggregate of several ppm in the recovered groundwater, even less than one
percent organo-mercury could be important considering the maximum allowable discharge
concentration was 10 ppb mercury. This was one of the reasons that activated carbon was
selected as a part of the treatment system. Rather than spend a great deal of time in
determining mercury speciation in the groundwaters, it was decided to approach the
problem on a direct, empirical basis. This led to the current waste treatment process
involving precipitation, carbon adsorption and ion exchange.
14
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VI. LABORATORY TESTING
A. Experimental Procedures
Mercury analyses were performed using the EPA Method 245.1 of cold vapor atomic
absorption spectroscopy (9) with the exception that sodium borohydride was used as a
reductant rather than stannous sulfate, upon the recommendation of the instrument
manufacturer, Perkin Elmer. The validity of this modification in EPA Method 245.1 was
substantiated by experiments described in Section VIII.
A Perkin Elmer Model 3030B AAS instrument was calibrated daily for mercury, and
a calibration verification record was maintained using data collected by the analysis of EPA
certified check standards. Preparation of standards for mercury analysis was performed in
accordance with the specifications in Methods for the Chemical Analysis of Water and Wastes
(9). Spiked samples were analyzed with each batch of samples to determine if matrix
interference existed, and frequent blanks were run to ensure there was no mercury carry
over during analysis.
i
Mercury concentrations in groundwaters, column effluents and regenerating
solutions were determined by linear regression calibration curves generated from four
point standard calibration analysis (9).
Samples collected in the field pilot studies were split and sent to Woodward-Clyde
Consultants, EER Technologies and Bio-Recovery Systems for mercury analysis.
Laboratory tests on the efficiency of mercury adsorption on AlgaSORB® were
conducted using small glass columns (1.5 cm i.d. x 20 cm) which contained 25.0 mL of
sorbent. Mercury-containing groundwaters were pumped through the column at flow rates
which varied from 6-20 bed volumes per hour. Effluents from the columns were collected
using a fraction collector and mercury content was determined. Once the columns became
saturated or leaked mercury above discharge limits (10 ppb), the column was stripped with
10 bed volumes of a selected stripping reagent followed by 10 bed volumes of deionized
water. Analyses of stripping effluents were performed to verify stripping.
More complete experimental procedures and data analyses are found in Section VIII.
Quality Assurance.
15
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B. Results
1. Water Analysis
Samples of groundwater were collected at various times during 1989. With one
exception all samples were acidified to pH 2 with nitric acid in the field prior to transport
for laboratory studies. Once the samples were received at Bio-Recovery Systems, the
solutions were neutralized to the original or desired pH with dilute sodium hydroxide.
Laboratory and field studies were complicated by the fact that over a 10 month period,
mercury concentrations changed by an order of magnitude. Table 3 shows mercury
concentration variation over the sampling period. While variations in mercury speciation
were not determined, laboratory studies with AlgaSORB® implied that the mercury
speciation varied over the sampling period. (See below).
TABLE 3. MERCURY CONCENTRATIONS IN GROUNDWATERS
Sample Number
103-13089
176-42089
177-42089-1
177-42089-2
265-070589
343-090189
368-100489
369-100489
Original
pH
8.5
8.0
8.0
8.0
7.9
7.8
7.9
7.9
Mercury
Concentration
ffifl/n
150
435
144
215
1120
620
1550
1550
Date
Collected
01-30-89
04-20-89
04-20-89
04-20-89
07-05-89
08-31-89
10-04-89
10-04-89
Variations in mercury content of samples 176-42089, 177-42089-1 and 177-
42089-2 are due to the method of preservation. Two five-gallon water samples were
collected on April 20, 1989. One sample, 177-42089-1, was not acidified in the field and
was transported unpreserved to Bio-Recovery where 5 L was removed for testing. The
remainder of sample 177-42089-1 was then acidified to pH 2, stored for use, and
designated as sample 177-42089-2. Sample 176-42089 was acidified in the field and was
transported to Bio-Recovery Systems for testing. It is clear that some mercury was lost
(perhaps due to container-wall adsorption) from sample 177-42089-1. Upon
acidification of the sample a slight increase in the mercury concentration was observed.
The waters shown in Table 3 were used for subsequent laboratory tests with
AlgaSORB®. Water samples were adjusted to various pH values and reanalyzed for mercury
just prior to AlgaSORB® testing. Thus mercury concentrations shown in subsequent tables
may vary slightly from those shown in Table 3.
16
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2. AlgaSORB® Tests
Acidified groundwater samples collected on January 30, 1989 (Sample 103-
13089) were adjusted to pH 6 and were pumped through an AlgaSORB®-602 column at a
flow rate of 10 bed volumes per hour. Table 4 shows mercury contents in the effluents
were well below the 10 ppb discharge limit through the passage of over 200 bed volumes of
sample. Table 4 also shows results
TABLE 4. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-602*
Bed Volume
of Effluent
Ha fua/L)
Spiked
Ha (u.a/L}
Recovery (%} Error (%)
1 -4
5-8
5-8t
9-12
13-16
21-24
105-108
121-124
141-144
141-144t
161-164
181-184
185-188
201-204
221-225
241-244
256-260
0.6
0.8
7.8t
0.5
0.5
0.8
2.1
2.7
2.0
7.7
4.4
4.6
1.7
3.5
11.7
30.0
16.7
0
10.0
70
30
0
10.0
57
43
* Influent mercury concentration was 150 \ig/L at pH 6.0.
f QA samples
Water sample 103-13089
for matrix spikes. Once 260 bed volumes of groundwater were passed through the column,
attempts were made to strip the column with 3.0 M sodium chloride. Table 5 shows results
of stripping experiments. While some mercury was stripped with sodium chloride, mass
balance calculations showed that only 30 percent of the loaded mercury was recovered in
stripping. Based upon this poor recovery, sodium chloride was deemed to be inappropriate
as a stripping agent.
17
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TABLE 5. ANALYSIS OF STRIPPING EFFLUENTS FROM COLUMN LOADED IN TABLE 4*
Bed Volumes
of Effluent
Ha (u.a/U
1 -4
5-8
9-12
13-16
17-20
1290
515
208
1.
0.8
* Stripping solution was 3.0 M NaCI.
A second column of AlgaSORB®-602 was prepared and groundwater sample
103-13089 which was adjusted to pH 5 was loaded onto the column at a flow rate of 10 bed
volumes per hour. Table 6 shows results of mercury analysis of effluent fractions.
TABLE 6. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-602*
Bed Volumes
of Effluent
Ha (u.a/L\
Spiked
Ha (ua/Ll
Recovery (%)
Error (%)
1 -4
17-20
37-40
37-40t
57-60
73-76
77-80
93-96
1 13-116
133-136
133-136t
149-152
0.50
0.80
0.65
10.7t
4.0
2.2
5.6
2.3
3.0
2.5
9.9t
6.5
0
10.0
0
10.0
100
74
26
* Influent mercury concentration was 150 jxg/L at pH 5.0.
t QA samples
Water sample 103-13089.
Good mercury retention by the AlgaSORB® was observed through the passage of 152 bed
volumes of groundwater. Similar mercury binding performance was observed at pH 6
(Table 4) and at pH 5.0 (Table 6).
18
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Sample 177-42089-1 (unpreserved at pH 8.0) was adjusted to pH 5.0 and was
loaded onto an AlgaSORB®-602 column at a flow rate of 10 bed volumes per hour. A total of
168 bed volumes of effluent was collected and analyzed for mercury. Table 7 shows results
of these analyses. After passage of 168 bed volumes, mercury concentration in the effluent
was 27 ppb, which is a much higher leakage rate than observed with the same adsorbent on
sample 103-13089. (Table 6 shows effluents had mercury contents below 7 ppb after
passage of 152 bed volumes of sample 103-13089.)
Sample 176-42089 (acid preserved) was loaded onto another AlgaSORB®-602
column at a flow rate of six bed volumes per hour and at pH 5.0. Seventy six bed volumes of
effluent were collected, and then the column was stripped of mercury by the passage of 10
bed volumes of 1.0 M sodium thiosulfate followed by 10 bed volumes of distilled water. Once
the first loading and stripping cycle was completed, it was repeated twice more.
TABLE 7. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH
AlgaSORB®-602*
Bed Volumes
of Effluent
1 -4
17-20
33-36
33-36t
69-72
1 17-120
165-168
Spiked
Hg f(xg/L^ Hg (\ig/L\
42
2.0
3.8 0
14.6t 10
8.3
12.8
26.8
Recovery 1%) Error (%)
108 8
Influent mercury concentration was 144 ng/L at
QA sample
5- Water sample 177-42089.
Table 8 shows results of mercury analysis on effluents from the three loading cycles.
Again high leakage of mercury was observed with this water sample. Table 9 shows results
of the three stripping cycles. Mass balance calculations showed that 84, 88 and 76 percent
of bound mercury was stripped in stripping cycles 1, 2, and 3, respectively.
19
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TABLE 8. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-602*
Cvcle
1
2
3
Bed Volumes
of Effluent
1 -4
21-24
21-24t
37-40
57-60
73-76
1 -4
21-24
21-24t
41-44
57-60
73-76
1 -4
21-24
37-40
37-40t
53-56
73-76
Ha (\ia/L)
27
22
3lt
68
88
124
23
14
23.5t
37
44
53
8.8
1 1
11.8
28t
40
68
Spiked
Hg f|ia/L> Recovery (%) Error (%)
0
10 88 12
0
10 95 5
0
10 163 63
* Influent mercury concentration was 400 jxg/L at pH 5. Water sample 176-42089.
t QA sample
TABLE 9. ANALYSIS OF STRIPPING EFFLUENTS FROM COLUMN LOADED IN TABLE 8
Cvcle
1
2
3
Bed Volumes
of Effluent
1 -4
5-8
9-12
13-16
17-20
1 -4
5-8
9-1 2
13-1 6
17-20
1 -4
5-8
9-1 2
13-16
17-20
Ha fp.g/L)
5380
352
171
13
2.6
5300
625
352
141
60
4730
640
278
15
1 0
20
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A different lot of AlgaSORB®-602 was prepared and again tested on groundwater
sample 176-42089. The water was loaded at pH 5 onto a 25 mL column containing
AlgaSORB®-602 and after passage of 76 bed volumes the column was stripped with 10 bed
volumes of 1.0 M sodium thiosulfate and 10 bed volumes of deionized water. After the first
loading-stripping cycle a second loading-stripping cycle was done. Data for loading is shown
in Table 10 and for stripping in Table 11. Table 10 again shows high rates of mercury
leakage. Stripping of bound mercury was effective, however, with mass balance calculations
showing that 99 and 92 percent of bound mercury were stripped in cycles 1 and 2,
respectively.
TABLE 10. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-602*
Bed Volumes
Cvcle Of Effluent
1 1 -4
17-26
37-40
37-40f
53-56
73-76
2 1 -4
5-8
17-20
21-24
21-24f
37-40
37-40t
47-44
57-60
61 -64
69-72
73-76
Spiked
Hgf|xa/L^ Hg(|a.g/L^ Recovery (%)
9.9
10.1
6.8 0
21. 8f 10 150
14.6
31.0
77.5
1.4
3.1
2.1 0
14. 9f 10 128
7.2 0
14. 2f 10 70
8.6
7.6
10.0
7.6
11.5
Error <%}
50
28
30
* Influent mercury concentration was 400 jxg/L for Cycle 1 and 200 (ig/L for Cycle 2 and for both
cycles the pH was 5.0. Water sample 176-42089.
t QA samples
21
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TABLE 11. ANALYSIS OF STRIPPING EFFLUENTS FROM COLUMN LOADED IN TABLE 10
Cycle
1
2
Bed Volumes
of Effluent
1 -4
5-8
9-1 2
13-16
17-20
1 -4
5-8
9-1 2
13-16
17-20
Ha fua/n
6250
1020
230
16.4
5.3
2900
365
198
16.6
8.8
AlgaSORB®-602 clearly showed different mercury binding characteristics on water
sample 103-13089 (Table 4 and 6) as compared to sample 176-42-89 (Table 7, 8, 10).
Unacceptable mercury leakage was observed with the 176-42089 samples as compared to
the 103-13089. This suggests that the mercury speciation may have changed during the
time period between sample collections. >
Different algae have different mercury binding characteristics due to different
biopolymers present in the cell walls. Thus a different AlgaSORB®, AlgaSORB®-601, was
synthesized containing a different algal species and was tested on the 176-42089 waters.
Waters at pH 5.0 were loaded into an AlgaSORB®-601 column at a flow rate of 10 bed
volumes per hour. Mercury was stripped with thiosulfate as described earlier. Data for
four loading and stripping cycles on AlgaSORB®-601 are shown in Tables 12 and 13.
AlgaSORB®-601 was more effective in binding mercury than was AlgaSORB®-602. Table
12 shows that mercury leakage was below 10 ppb during all four loading cycles through the
passage of over 100 bed volumes of sample 176-42089.
22
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TABLE 12. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-601'
Cvcle
1
2
3
4
Bed Volumes of Effluent
1-4
21-24
37-40
37-40f
73-76
77-80
89-92
97-100
121-124
137-140
153-156
1-4
17-20
37-40
37-40|
17-20
68-72
73-76
85-88
101-104
117-120
132-135
1-4
21-24
21-24|
37-40
57-60
67-70
71-74
71-74f
91-94
97-100
107-110
117-120
121-124
121-124f
127-130
131-134
1-4
49-52
67-70
71-76
97-100
109-112
129-132
137-142
Ho: ((ifl/n Spike Hp (\itf/L\ Recoverv (°/0\ Error (%\
0.5
1.5
1.8 0
11. 5f 10.0 98 2
5.1
2.1
4.5
5.5
10.8
15.2
21.0
2.2
3.1
2.7 0
10.0f 9.0 82 18
3.1
8.9
3.8
5.9
9.8
16.5
31.2
0.7
1.4 0
10.2f 10.0 88 12
3.3
5.1
5.7
2.2 0
10.3 10.0 81 19
3.9
4.7
4.8
6.3
2.2 0
12.1f 10.0 00 1
4.4
4.5
1.1
5.3
7.1
2.1
3.6
5.2
7.2
7.3
Influent mercury concentrations were 506, 502. 255 and 283 (xg/L for Cycles 1, 2, 3, 4, respectively. All
influents were at pH 5.0. Water samples 176-42089 for Cycles 1 and 2; 177-42089 for Cycles 3 and 4
f QA sample.
23
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TABLE 13. ANALYSIS OF STRIPPING EFFLUENTS FROM COLUMN LOADED IN TABLE 12
Cvcle
1
2
3
4
Bed Volumes
of Effluent
1 -4
5-8
9-1 2
13-16
17-20
1 -4
5-8
9-1 2
13-16
1 7-20
1 -4
5-8
9-1 2
13-16
17-20
1 -4
5-8
9-1 2
13-16
17-20
Hq (mq/L)
15,700
620
235
4
0.6
14,100
1,500
34
7.8
4.2
5,450
770
390
4.2
3.0
4,100
830
425
3.8
1.6
Mass balance calculations showed 84, 92, 75 and 59 percent of the bound mercury was
stripped from the columns during stripping Cycles 1, 2, 3 and 4, respectively (Table 13).
Yet a third alga was immobilized to produce AlgaSORB®-603. This adsorbent was
tested in the same manner as AlgaSORB®-602 (Tables 4, 6) and AlgaSORB®-601 (Table
12) on groundwater collected 4-20-89 as well as on a new groundwater sample collected
7-5-89 (Sample 265-070589). All water samples were loaded onto an AlgaSORB®-603
column at pH 5 and at flow rates of 10 bed volumes per hour. After loading, the columns
were stripped with thiosulfate as described earlier. Data for three loading and stripping
cycles are shown in Tables 14 and 15. AlgaSORB®-603 was more effective for mercury
removal than either AlgaSORB®-601 or AlgaSORB®-602 for Sample 176(177)-42089.
Mass balance calculations showed that 95, 86 and 99 percent of bound mercury was
recovered in stripping cycles 1, 2 and 3, respectively (Table 15).
24
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TABLE 14. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlciaSORB®-603*
Cvcle
1
2
3
Bed Volumes
of Effluent
1 -4
17-20
37-40
37-40f
57-60
73-76
77-80
93-96
93-96f
113-116
133-136
149-152
153-156
157-160
161-164
169-172
177-180
1 - 4
21-24
37-40
37-40f
57-60
73-76
77-80
89-92
97-100
1 17-120
137-140
149-152
1 -4
21-24
61-64
89-93
100-103
104-108
104-108t
113-116
121-124
129-132
137-140
Spike
Ha (\ig/L) Hg fp.g/L^ Recovery (%)
2.8
2.1
1.4 0
10. 8f 10.0 94
3.5
4.5
3.5
2.2 0
12.4t 10.0 102
8.0
11.7
16.6
6.2
8.1
8.0
9.9
11.1
0.5
0.9
1.0 0
8.7f 10.0 77
4.1
6.1
8.9
5.9
6.1
8.9
10.6'
14.3
6.6
1.6
3.9
8.8
10.5
4.0 0
13.2t 10.0 92
14.2
16.8
24.6
34.0
Error (%]
6
2
23
8
* Influent mercury concentration for Cycle 1 was 268 ng/L and was Sample 177-42089. Influent
mercury concentration for Cycles 2 and 3 were 1160 and 910 p.g/L, respectively and was
Sample 265-070589. All Cycle influents were at pH 5.0
t QA samples
25
-------
TABLE 15. ANALYSIS OF STRIPPING EFFLUENTS FROM COLUMN LOADED IN TABLE 14
Cvcle
1
2
3
Bed Volumes
of Effluent
1 -4
5-8
9-1 2
13-16
17-20
1 -4
5-8
9-1 2
13-16
17-20
1 -4
5-8
9-1 2
13-1 6
17-20
Ha (jia/U
10,800
540
192
4.4
3.8
31,000
1,250
3,200
2.0
0.8
28,200
2,290
1,250
7.0
0.6
AlgaSORB®-602 was also tested on water Samples 265-070589. Results of that
testing, under conditions as used for other sample testing, are shown in Table 16.
TABLE 16. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-602*
Bed Volumes
of Effluent
1-41.3
21-24
41-44
41-44f
57-60
69-72
Ha ua/Ll
3.4
0.8
8.1f
27.0
72.5
Spike
Ha fun/Li
0
10.0
Recovery (%} Error (%)
73 27
Influent mercury concentration was 940 ng/L at pH 5.0. Water sample 265-070589.
t QA sample
The mercury concentration in water at the site had increased to nearly 1 mg/L by the time
sample 265-070589 was taken and AlgaSORB®-602 showed unacceptable leakage rates.
26
-------
New water samples were collected on 9-1 -89. Since AlgaSORB®-603 appeared to be
the best formulation for waters collected on 4-20-89 and 7-5-89, it was tested on water
sample 343-090189. Data are shown in Table 17. Conditions of pH and flow rates were
those described earlier. It is clear from Table 17, that very high unacceptable mercury
leakage occurred.
AlgaSORB®-603 had proved to be effective in mercury recovery from samples 177-
42089 and 265-070589 which contained 268 ppb and 1160 ppb, respectively, of
mercury (Table 14). Table 17 shows that at mercury levels of 620 ppb in sample 343-
090189, poor mercury recovery was observed with AlgaSORB®-603. These data again
suggested that mercury speciation was changing in waters taken from the site which would
account for the variation in mercury binding for different water samples.
Because of the inconsistency of performance of various AlgaSORB® preparations with
different water samples, a different approach was taken.
TABLE 17. ANALYSIS OF EFFLUENTS FROM A COLUMN PACKED WITH AlgaSORB®-603*
Bed Volumes
of Effluent
Ha (aa/Ll
1
7
1 3
1 9
2.6
36.0
37.0
42.0
* Influent mercury concentration was 620 jj.g/L at pH 5.0. Water Sample 343-090189.
Work performed previous to this study indicated that two other AlgaSORB®
preparations, AlgaSORB®-624 and AlgaSORB®-640, may be effective for mercury removal
even if mercury concentration and/or mercury speciation changed in solutions. AlgaSORB®-
624 had shown high mercury binding capacities but also rather high mercury leakage on the
order of 20-40 ppb. AIgaSORB®-640, on the other hand, showed rather low mercury
binding capacities, but at the same time, produced effluents which contained mercury in the
low ppb range. Thus two columns, one containing AlgaSORB®-624 and the other containing
AlgaSORB®-640 were prepared and connected in series. Groundwater Sample 343-090189
was adjusted to pH 7.9, the native pH, and was first passed through the AlgaSORB®-624
column and then through the AlgaSORB®-640 column. Data for these experiments are shown
in Table 18. Table 19 shows repeat experiments of Table 18 using water sample 369-
100489, collected on October 4, 1989.
27
-------
TABLE 18. ANALYSIS OF EFFLUENTS FROM TWO
COLUMNS IN SERIES PACKED WITH AlgaSORB®-624 and AlgaSORB®-640*
Bed Volumes
of Final Effluent
Ha (ua/L)
12
34
43
60
80
104
113
121
130
140
159
170
180
190
200
210
230
0.0
0.0
0.6
1.8
3.3
3.4
2.9
3.9
4.4
3.2
7.5
4.0
3.5
0.1
0.1
0.1
2.3
Influent waters were sample 343-090189 (mercury concentration 620 (ig/L) for the first 90
bed volumes. Sample 368-100489 (mercury concentration of 1550 (xg/L) provided influent for
bed volumes 91-230.
28
-------
TABLE 19. ANALYSIS OF EFFLUENTS FROM
TWO COLUMNS IN SERIES PACKED WITH AlgaSORB®-624 AND AlgaSORB®-640*
Bed Volumes
Hg (H9/L)
1 2
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
228
264
276
300
324
333
0.3
0.2
' 0.3
0.3
0.3
0.5
0.5
0.7
0.7
0.8
0.8
0.9
0.9
1.0
0.8
0.8
0.9
0.9
0.6
1.2
2.1
2.0
1 .9
Influent waters were Sample 369-100489 (mercury concentration 1550 jxg/L) at pH 7.9.
29
-------
VII. ON-SITE, PILOT SCALE DEMONSTRATION
On-site, pilot scale demonstrations were conducted using AlgaSORB®-624 and
AlgaSORB®-640 as adsorbents. A small portable water treatment system manufactured by
Bio-Recovery Systems was used for these studies (Figure 3). This portable unit is designed
so that columns ranging in size from 1-4 inches in diameter can be placed on the unit. For
the pilot testing one inch diameter columns were used. Based upon laboratory experiments
it was predicted that one-inch diameter columns would become saturated with mercury in
3-4 weeks at flow rates of 10 bed volumes per hour.
One column was filled with AlgaSORB®-624 and the second column was filled with
AlgaSORB®-640. Each column had a volume of 0.4 L. The two columns were run in series so
that groundwater, with no pH adjustment, was directed first through the AlgaSORB®-624
column and then through the AlgaSORB®-640 column. Effluent samples were collected from
a sample port between the two columns as well as from effluent emanating from the second
column. Effluent samples were split into three portions. One portion was sent to
Woodward-Clyde Consultants for immediate mercury analysis (within 12-24 hours of
collection). Another portion was acid-preserved and sent to EER Technology for mercury
analysis, while the third portion was preserved and sent to Bio-Recovery Systems for
analysis.
On-site pilot scale testing was conducted from November 6 to December 1, 1989.
The site was available for testing only from 7:OOAM-3:30PM each day. At the end of a
treatment day, the system was simply shut down and then restarted the next day. Flow rates
through the system were 10 bed volumes per hour.
By the time the on-site testing had begun in November, the mercury concentrations
In the groundwaters had changed from about 1500 ppb (in October) to 780 ppb on
November 7. During the three week on-site test period the mercury concentration
continued to vary. Table 20 shows mercury concentration variations during the on-site test
period. Mercury was found to vary from as low as 330 ppb to as high as 1000 ppb.
30
-------
Figure 3. Portable Waste Treatment System Used for On-Site Testing
-------
TABLE 20. VARIATION IN MERCURY CONTENT
OF GROUNDWATERS DURING ON-SITE PILOT SCALE TESTING
Pate
Mercury*
Concentration (\ig/\-)
11/07/89
1 1/08/89
11/09/89
11/10/89
11/14/89
11/15/89
1 1/16/89
1 1/17/89
11/20/89
11/21/89
1 1/27/89
11/28/89
11/29/89
11/30/89
780
500
332
490
810
700
730
690
850
970
1000
1000
730
590
Each day during on-site testing, a
through the columns.
water sample was analyzed for mercury content before any water was pumped
Results of mercury analyses on effluents from the complete test system, i.e., from
the effluent from the second column are shown in Table 21. Table 21 shows analytical data
for only a portion of all collected samples. Full data with matrix spikes and QC/QA data are
found In Appendices A and B.
32
-------
TABLE 21. ON-SITE PILOT TESTING FOR MERCURY REMOVAL FROM GROUNDWATERS*
Bed Volumes
of Effluent
7-8
85-86
163-64
229-230
289-290
313-314
343-344
379-380
415-416
449-450
467-468
503-504
533-534
587-588
Bio-Reqovery
Analysis
9.5
5.3
2.1
1.4
1.8
1.9
5.5
2.0
1.8
4.9
4.0
5.8
7.7
10.5
...Mercury Concentration
Woodward-Clyde
Analysis
14.2
8.0
3.6
1.4
2.6
2.4
9.3
3.1
3.2
7.8
7.2
9.6
10.0
13.0
...fuo/U
EER Technologies
Analysis
1 1
<10
<10
<10
<10
<10
10.0
<10
<10
10.0
<10
<10
<10
15
A portable water treatment system was equipped with two columns connected in series. The first column was filled
with AlgaSORB®-624 and the second was filled with AlgaSORB®-640. Groundwaters were pumped through the system at
a flow rate of 6 bed volumes per hour. Effluent samples were collected and sent to Woodward- Clyde Consultant, EPA
(EER Technologies Corporation) and Bio-Recovery systems for analysis.
With the exception of the first fraction collected, Table 21 shows that well over 500
bed volumes of mercury-contaminated groundwaters were treated before mercury
concentrations in the effluents approached the 10 ppb discharge limit.
During on-site testing, samples were collected from the sample port between the two
columns and were sent to Woodward-Clyde for mercury analysis. These samples represent
water treated only by AlgaSORB®-624 prior to entering the AlgaSORB®-640 column. Data
from these analyses are shown in Table 22. These data show rather constant leakage of
mercury from the first column in the range of 20-100 ppb over the testing period. The
data in Table 20, 21, and 22 confirm laboratory experiments which showed AlgaSORB®-
624 was capable of removing the majority of the mercury and AIgaSORB®-640 was capable
of polishing effluents from AlgaSORB®-624 to permitted discharge levels.
33
-------
TABLE 22. ANALYSIS OF EFFLUENTS FROM THE AlgaSORB®-624
COLUMN ON THE PORTABLE TREATMENT SYSTEM
Bed Volumes
of Effluent
Mercury Concentration*
(ua/Ll
1-261
262
281
316
333
352
382
413
429
446
47,0
495
518
542
561
585
Not Determined
28
40
33
38
33
26
90
120
38
46
53
54
68
61
107
Analysis by Woodward-Clyde Consultants.
34
-------
VIII. QUALITY ASSURANCE
The objective of this program was to demonstrate effective mercuiy removal and
recovery from groundwaters. The critical data needed to support this objective were
measurements of mercury concentrations in water prior to treatment and after treatment.
A quality assurance project plan was developed for these measurements and was approved in
December, 1988.
A. Verification of Modification of EPA Method 245.1 for Mercury Analysis
Since the manufacturer of the cold vapor apparatus used in this study recommended
the use of sodium borohydride instead of stannous sulfate or stannous chloride as a reducing
agent, initial experiments were designed to verify the validity of using sodium borohydride
as a reductant.
Two standard stock solutions containing mercury at a concentration of 1000 ppm
were purchased, one from VWR and the other from J. T. Baker. The VWR standard was used
solely by the analyst while the J.T. Baker standard sample was used solely by the QA chemist
for spikes.
In initial tests a 100 ppb serial dilution of the VWR mercury standard was prepared
by the project supervisor. This 100 ppb sample was used by the analyst to calibrate the
atomic absorption spectrometer and by the QA chemist to prepare spiked samples to check
calibration. These experiments were designed to verify that techniques employed by the
analyst and QA chemist were comparable. Results are shown in Table 23. ,
TABLE 23. MERCURY ANALYSIS OF STANDARDS USING SODIUM BOROHYDRIDE AS A
REDUCTANT
Sample
1
2
3
4
5
6
Actual Mercury
Concentration (fig/L)
6.0
6.0
12.0
12.0
18.0
18.0
Analyzed Mercury
Concentration fjig/L}
6.0
6.0
11.3
10.6
15.4
16.1
Percent
Error
0.0
0.0
6
1 1
1 4
1 1
A second series of experiments were designed whereby the project supervisor
prepared a 100 ppb mercury-containing sample from the VWR stock for the analyst and a
35
-------
100 ppb mercury-containing sample from the J.T. Baker stock for the QA chemist. The
analyst used his 100 ppb sample to calibrate the instrument and the QA chemist used her
sample for spikes to check calibration. Results of these experiments are shown in Table 24.
TABLE 24. MERCURY ANALYSIS OF STANDARDS USING SODIUM BOROHYDRIDE AS A
REDUCTANT
Sample
1
2
3
4
5
6
7
8
9
1 0
1 1
12
Actual Mercury
Concentration <\ia/L)
6.0
6.0
11.0
11.0
16.0
16.0
6.0
6.0
12.0
12.0
18.0
18.0
Analyzed Mercury
Concentration (]iq/L
5.7
5.6
10.7
9.5
15.3
15.8
5.1
5.3
10.0
11.3
16.7
16.7
Percent
Error
5
7
3
1 4
4
1
1 5
1 2
1 7
6
7
7
B. Analysis of EPA-Provided Standard
The EPA Environmental Monitoring Systems Laboratory in Cincinnati sent
Bio-Recovery Systems a standard Water Pollution Quality Control Sample for testing. The
sample contained 15 different metal ions including mercury which.was present both in
inorganic and organic forms. The ampule containing the standards was opened by snapping
the top at the break area on the neck, and 10.0 mL of the concentrate was transferred to a
1.0 L volumetric flask, brought to volume and analyzed. Actual concentrations of metals in
the sample are shown in Table 25. Actual mercury content in the EPA sample was 5.0 u.g/L.
Results from Bio-Recovery analysis of the sample are shown in Table 26. According to EPA,
analyzed mercury values must fall within the range of 3.85-6.25 u,g/L in order to be
within the 95 percent confidence interval. Table 26 shows that 8 of the 11 analytical
determinations for mercury were within the 95 percent confidence level.
36
-------
TABLE 25. ERA-PROVIDED SAMPLE INFORMATION
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory - Cincinnati
WATER POLLUTION QUALITY CONTROL SAMPLE
TRUE VALUES FOR TRACE METALS -1
The true values (T.V.) given below represent the actual weighing and all subsequent
dilutions as given in the sample preparation instructions. The mean (X), standard deviation
(S) and 95% confidence interval (X ±2S) are calculated from regression equations
generated from date from previous Performance Evaluation Studies. Table 25 represents
the statistics when the sample preparation instructions are followed.
STATISTICS USING SAMPLE PREPARATION INSTRUCTION
(All values expressed as u,g/L)
Parameter
S
Al
As
Be
Cd
Co
Cr
Cu
Fe
Hg
Mn
Ni
Pb
Se
V
Zn
500
100
100
25
100
1 00
100
100
5.0
100
100
100
25
250
100
506.0
99.2
99.4
24.4
99.5
99.8
99.1
100.2
5.05
98.8
100.4
100.1
22.8
250.9
99.8
39.4
9.60
5.37
1.64
6.31
7.68
4.83
8.78
0.60
5.21
6.20
7.50
2.73
15.5
5.44
427
80.0 -
88.7 -
21.2 -
86.8 -
84.4 -
89.4 -
82.7 -
3.85-
88.4 -
88.0 -
85.1 -
17.4 -
220
89.0 -
585
118
1 10
27.7
1 1 2
115
109
118
6.25
109
113
115
28.3
282
1 1 1
37
-------
TABLE 26. MERCURY ANALYSIS OF EPA
WATER POLLUTION QUALITY CONTROL SAMPLE*
Trial
Number
1
2
3
4
5
6
7
8
9
1 0
1 1
Analyzed Mercury
Concentration (\ig/L)
6.4
6.9
6.1
6.7
5.4
5.3
5.2
5.1
5.2
4.6
4.8
Within 95 percent
Confidence Interval
No -
No -
Yes
No -
Yes
Yes
Yes
Yes
Yes
Yes
Yes
2.4%>6.25
10.4%>6.25
7.2%>6.25
The actual mercury contraction in the sample was 5.0 (ig/L.
confidence level is 3.85-6.25
The accepted range at 95 percent
38
-------
C. Mercury Spikes
During the course of testing various AlgaSORB® preparations for efficiency of
mercury binding, the analyst was given samples of groundwater effluents from AlgaSORB®
columns which had been spiked by the QA chemist with amounts of mercury unknown to the
analyst. Section VI shows tables including the amount of spiked mercury as well as the
percent error and the percent recovery of the mercury spikes. However Table 27.
summarizes all mercury spikes. From a total of 36 spiked samples, analysis of 26 samples
TABLE 27. ERROR AND RECOVERY ANALYSIS OF MERCURY SPIKES
Spike
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
, 10
10
. .. 10
10
10
10
10
10
10
10
10
10
Percent
Error
32
43
3
0.5
26
27
67
213
23
40
12
5
63
50
28
30
3
19
12
19
1
42
15
215
19
0.5
8
6
2
23
8
7
130
147
27
10
Percent
Recovery
68
57
97
100.5
74
127
167
313
123
140
84
95
163
150
128 ,
70
97
81
88
81
99
142
115
315
81
100.5
108
94
102
77
92
93
230
247
73
110
39
-------
were within the allowable 35 percent error range giving a 73% accuracy level on spike
recovery.
D. Mercury Analysis in the Presence of Thiosulfate.
During the course of stripping the bound mercury from the AlgaSORB® columns using
1.0 M sodium thiosulfate, an analytical problem was encountered. The presence of
thiosulfate appeared to interfere with mercury analysis (Table 28.)
TABLE 28. EFFECT OF THIOSULFATE ON MERCURY ANALYSIS*
Actual Mercury
ffia/D
0
1000
2000
Analyzed Mercury
(\IQ/L]
1
356
528
Percent
Error
64
74
* All mercury standard samples contained 1.0 M Na2S2O3
Further investigation revealed that acid digestion of samples containing high
concentrations of thiosulfate produced the interference. Thus attempts were made to
alleviate the interference by oxidizing the thiosulfate with hydrogen peroxide at different
pHs prior to acid digestion. ' Results of these experiments, shown in Table 29 indicated
peroxide oxidation did not alleviate the problem.
TABLE 29. ANALYSIS OF MERCURY-THIOSULFATE SAMPLES OXIDIZED WITH HYDROGEN
PEROXIDE*
Oxidation
pH
2
5
8
2
5
8
2
5
8
2
5
Ratio of Peroxide
to Thiosulfate (Molart
1.0
1.0
1.0
2.0
2.0
2.0
5.0
5.0
5.0
10.0
10.0
Actual
Mercurv <[ia/L)
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
Analyzed
Mercurv (\ia/L)
270
155
210
240
130
105
290
150
160
105
105
Percent
Error
73
85
79
76
87
90
71
85
84
90
90
All mercury standard samples were in presence of 1.0 M Na2S2O3
40
-------
The analytical interference problem was finally overcome by eliminating the acid
digestion as prescribed in EPA Method 245.1. Table 30 shows results of these analyses.
TABLE 30. MERCURY ANALYSES OF THIOSULFATE CONTAINING
SOLUTIONS WITHOUT ACID DIGESTION*
1 0
20
1000
1000
1000
500
500
500
1 0
5
1000
1000
1000
500
500
500
8.2
16.2
1070
1070
1020
540
540
510
9.3
4.5
1010
1030
1060
560
520
530
roiocui E:nui
1 8
1 9
7
7
2
8
8
2
7
1 0 ,
1
3
6
1 2
4
6
* All mercury standard samples contained 1.0 M Na2S2O3
Table 30 clearly shows that elimination of the acid digestion step also eliminated the
interference in the mercury analysis. Thus all AlgaSORB® column eluents resulting from
stripping with thiosulfate were analyzed without the acid digestion step.
E. Analysis of Samples Resulting from On-Site Testing.
During on-site pilot scale testing of AlgaSORB® for mercury recovery from
groundwaters, Effluents from A!gaSORB®-containing columns were collected, preserved,
split and sent to EER Technologies (Cincinnati), Woodward-Clyde Consultants (Oakland) and
Bio-Recovery Systems for mercury analysis. Results from Bio-Recovery Systems analysis
and QC data have been reported earlier in Section VII. Sample numbers, and bed volumes of
column effluent and influent to which sample numbers correspond are listed in Table 31.
Appendices A and B show mercury analysis and QC data for Woodward-Clyde and EER
Technologies, respectively.
41
-------
TABLE 31. IDENTIFICATION OF SAMPLES SENT
TO WOODWARD-CLYDE CONSULTANTS AND EER TECHNOLOGIES
FOR MERCURY ANALYSIS
Sample Number
436-110789
437-110789
438-110789
439-110789
440-110789
441-110789
442-110789
443-110789
444-110889
445-110889
446-110889
447-110889
448-110889
449-110889
450-110889
451-110889
452-110889
453-110889
457-110989
458-110989
459-110989
460-110989
461-110989
462-110989
463-110989
464-110989
465-110989
466-110989
Description*
Influent
Blank
1-2 BV
7-8 BV
13-14 BV
19-20 BV
25-26 BV
31-32 BV
37-38 BV
43-44 BV
49-50 BV
55-56 BV
61-62 BV
67-68 BV
73-74 BV
79-80 BV
Blank
Influent
85-86 BV
90-92 BV
97-98 BV
103-104 BV
109-110 BV
115-116 BV
121-122 BV
127-128 BV
Blank
Influent
Hq (ua/U
780
0.4
0.5
14.2
2.6
2.4
2.2
3.7
4.1
7.1
7.1
7.6
7.3
8.1
8.0
8.1
ND
500
8.0
8.4
10.4
10.7
10.4
10.4
10.9
10.5
ND
332
Samole Number
473-111389
474-111389
475-111389
476-111389
477-111389
478-111389
479-111389
480-111389
481-111389
482-111389
487-111489
488-111489
489-111489
490-111489
491-111489
492-111489
493-111489
494-111489
495-111589
496-111589
497-111589
498-111589
499-111589
500-111589
501-111589
502-111589
503-111689
504-111689
Description
Blank
Influent
133-134 BV
139-140 BV
145-146 BV
151-152 BV
157-158 BV
163-164 BV
169-170 BV
175-176 BV
Blank
Influent
181-182 BV
187-188 BV
193-194 BV
199-200 BV
205-206 BV
211.212 BV
217-218 BV
223-224 BV
229-230 BV
235-236 BV
241-242 BV
247-248 BV
Blank
Influent
253-254 BV
259-260 BV
* Hq fua/U
0.5
490
13.0
3.3
2.8
3.1
3.0
3.6
3.0
3.1
ND
810
2.5
2.7
4.8
2.5
2.2
2.7
4.1
2.3
1.4
2.1
2.3
2.7
ND
700
4.3
2.6
BV, unless otherwise indicated, designates bed
collected into a single fraction.
volumes of effluent from the second column
42
-------
TABLE 31. - continued
Sample Number
505-111689
506-111689
507-111689
508-111689
509-111689
510-111689
511-111689
512-111689
513-111689
514-111789
515-111789
516-111789
517-111789
518-111789
519-111789
520-111789
521-111789
522-111789
526-111789
524-111789
525-111789
526-112089
Description*
265-266 BV
271-272 BV
277-278 BV
283-284 BV
289-290 BV
Blank
Influent
Lead Col Effluent
@ 262 BV
Lead Col Effluent
@281 BV
295-296 BV
301-302 BV
307-308 BV
313-314 BV
319-320 BV
325-326 BV
331-332 BV
337-338 BV
Blank
Influent
Lead Col Effluent
@316 BV
Lead Col Effluent
@ 333 BV
Influent
Hg (\ig/L)
2.6
2.7
2.6
2.9
2.6
ND
730
28
40
4.0
2.4
2.4
2.4
2.5
2.3
2.4
2.8
ND
690
33
38
850
Sample Number Descriotion* Hn fim/l \
527-112089
528-112089
529-112089
530-112089
531-112089
532-112089
533-112089
534-112089
535-112089
536-112089
537-112089
538-112189
539-112189
540-112189
541-112189
542-112189
543-112189
544-112189
545-112189
546-112189
547-112189
548-112189
549-112189
343-344 BV
349-350 BV
355-356 BV
361-362 BV
367-368 BV
373-374 BV
379-380 BV
385-386 BV
Lead Col Effluent
@ 352 BV
Lead Col Effluent
@ 382 BV
Blank
Influent
Blank
391-392 BV
397-398 BV
403-404 BV
409-410 BV
415-416 BV
421-422 BV
427-428 BV
431-432 BV
Lead Col Effluent
@413BV
Lead Col Effluent
@ 429 BV
9.3
4.1
0.3
0.5
0.8
2.6
3.1
4.1
33
26
3.0
970
1.3
4.3
3.4
6.3
4.6
3,2
2.9
2.7
2.5
90
120
BV, unless otherwise indicated, designates bed volumes of effluent from the second column
collected into a single fraction.
43
-------
TABLE 31. - continued
Samel© Number
550-112789
551-112789
552-112789
553-112789
554-112789
555-112789
556-112889
557-112889
558-112889
559-112889
560-112889
561-112889
562-112889
563-112889
564-112889
565-112889
566-112889
567-112889
588-112989
589-112989
590-112989
Description*
Influent 1
Blank
437-438 BV
443.444 BV
449-450 BV
Lead Col Effluent
@ 446 BV
Influent 1
Blank
455-456 BV
461-462 BV
467-468 BV
473-474 BV
479-480 BV
485-486 BV
491-492 BV
497-498 BV
Lead Cot Effluent
@ 470 BV
Lead Col Effluent
@ 495 BV
Influent
Blank
503-504 BV
Ha (u.a/U
,000
0.1
12.2
8.0
7.1
38
,000
1.0
10.5
7.7
7.2
6.9
7.2
7.5
7.5
7.7
46
53
730
.08
9.6
Sample Number
591-112989
592-112989
593-112989
594-112989
595-112989
596-112989
597-112989
598-112989
599-112989
600-113089
601-113089
602-113089
603-113089
604-113089
605-1 13089
606-113089
607-113089
608-113089
609-113089
610-113089
Description
509-510 BV
515-516 BV
521-522 BV
527-528 BV
533-534 BV
539-540 BV
545-546 BV
Lead Col Effluent
@ 518 BV
Lead Col Effluent
@ 542 BV
Influent
Blank
551-552 BV
557-558 BV
563-564 BV
569-570 BV
575-576 BV
581-582 BV
587-588 BV
Lead Col Effluent
@ 561 BV
Lead Col Effluent
@ 585 BV
* Hg (MI/IT)
10.1
9.7
9.9
10.3
10.7
10.7
10.6
54
68
590
.08
13.9
12.1
12.8
13.2
13.2
13.2
13.0
61.0
107.0
BV, unless otherwise indicated, designates bed volumes of effluent from the second column
collected into a single fraction.
44
-------
IX. REFERENCES
1. Hanson, B., J. Haley, C. Enfield, and J.GIass, "Effectiveness of Groundwater Extraction-
Technical Consideration, Field Experience, Policy Implications, Proc. 10th National
Conference Superfund '89, November 27-29, 1989, Hazardous Materials Control
Research Institute, Silver Spring, MD., 1989, pp. 501-502.
2. Darnall, D.W., B. Greene, M. Hosea, R.A. McPherson, M. Henzl and M.D. Alexander
"Recovery of Heavy Metal Ions by Immobilized Alga," in Trace Metal Removal frnm
Aqueous Solution, R. Thompson ed.. London: Royal Society of Chemistry, Special
Publication No. 61, pp. 1-24 (1986).
3. Greene, B. and D. W. Darnall. "Algae for Metal Binding," in Microbial Metal Recovery.
H. Ehrlich, J. Brierley, and C. Brierley, eds., New York, NY: McGraw-Hill, 277-302
(1 990).
4. Robinson, P.K., A.L. Mabe and M.D. Trevan, "Immobilized Algae" A Review Process
Biochemistry 21: 122-127 (1986).
5. Bedell, G.W. and D.W. Darnall, "Immobilization of Non-Viable, Biosorbent Algal
Bio-mass for. the Recovery of Metal Ions", in Biosorbents and Blosorptlnn Recovery of
Heavy MelalS. B. Volesky ed., Boca Raton, FL: CRC Press, in press. (1990).
6. Darnall, D.W., B. Greene, M. Henzl, J.M. Hosea, R.A. McPherson, J. Sneddon and M D
Alexander, "Selective Recovery of Gold and Other Metal Ions from an Algal Biomass"'
Environmental Science and Ter.hnnlngy ?n- 206-208 (1986).
7. Greene, B.,M, Hosea, R.McPherson, M. Henzl, M.D. Alexander and D.W. Darnall
Interaction of Gold (1) and Gold (111) Complexes with Algal Biomass", Environmental
Science and Technology 20:627-632 (1986).
8. Darnall, D.W., A.M. Gabel and J. Gardea-Torresdey. "AlgaSORB® A New Biotechnology
for Removing and Recovering Heavy Metal Ions from Groundwater and Industrial
Wastewater , in Proc. of the 1989 A & WMA/EPA Intl. Symp. on Hazardous Waste
Treatment: Biosystems for Pollution Control, Air & Waste Management Association
Pittsburgh, pp 113-124 (1989).
9. Methods for the Chemical Analysis of Water and Wastes. EPA-600/4-79-020 US
Environmental Protection Agency, Revised March 1983 and subsequent EPA-600/4
Technical Additions Thereto, Cincinnati, Ohio, 1983.
45
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