February 1993
EPA/540/R-93/500
TECHNICAL PAPERS
FOURTH FORUM ON INNOVATIVE HAZARDOUS WASTE
TREATMENT TECHNOLOGIES:
DOMESTIC AND INTERNATIONAL
San Francisco, CA
November 17-19, 1992
TECHNOLOGY INNOVATION OFFICE
OFFICE OF SOLID WASTE AND EMERGENCY RESPONSE
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, DC 20460
AND
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
Printed on Recycled Paper,
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ABSTRACT
On November 17-19, 1992, the U.S. Environmental Protection Agency's Technology
Innovation Office and Risk Reduction Engineering Laboratory, Department of Energy,
Corps of Engineers, and California Environmental Protection Agency, hosted an
international conference in San Francisco, CA, to exchange solutions to hazardous waste
treatment problems. This conference, the Fourth Forum on Innovative Hazardous Waste
Treatment Technologies: Domestic and International, was attended by approximately
1,000 representatives from the U.S. and 25 foreign countries. During the conference,
scientists and engineers representing government agencies, industry, and academia
attended 42 technical presentations and case studies describing domestic and
international technologies for the treatment of waste, sludges, and contaminated soils at
uncontrolled hazardous waste disposal sites. Technologies included physical/chemical,
biological, thermal, and stabilization techniques. Presentations were made by EPA, their
Superfund Innovative Technology Evaluation (SITE) program participants, other Federal
and State agencies and their contractors, international scientists and vendors. Over 70
posters were on display.
This compendium includes the papers that were made available by authors and their
institutions. The papers are published as received and the quality may vary.
Although this document has been published by the U.S. Environmental Protection
Agency, it does not necessarily reflect the views of the Agency, and no official
endorsement should be inferred. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
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TABLE OF CONTENTS
ABR-CIS bioremediation: full-scale experiences with an in-situ treatment system
for sediment volume-reduction and contaminant mineralisation in harbours and
waterways
B. Malherbe, HAECON N.V., Harbour and Engineering Consultants 1
In Situ Bioventing of a Diesel Fuel Spill
T.L. Bulman, Campbell Environmental 22
Remediation of Ground Water Contaminated with Organic Wood Preservatives
Using Physical and Biological Treatment Technologies
J.G. Mueller, SBP Technologies, Inc 35
The Design Criteria and Economics of Operating a Full-Scale Above-Ground
Bioremediation Facility for the Treatment of Hydrocarbon Contaminated Soils
Robert Mall, KJC Operating Company 40
Biopur® An Innovative Bioreactor for the Simultaneous Treatment of
Groundwater and Soil Vapour Contaminated with Xenobiotic Compounds
J.M.H. Vijgen, TAUW Infra Consult, B.V 48
Bio-Rem Inc.'s Augmented In Situ Subsurface Bioremediation Process (TM)
Using Bio-Rem, Inc.'s Proprietary Biocultures (H-10) for the Remediation of
JP-4 Contaminated Soils at Williams AFB, AZ
David Mann, Bio-Rem, Inc 62
Bioremediation of Soils at a Waste Oil Facility
Gary Guerra, U.S. EPA, Robert S. Kerr Environmental Laboratory 64
Low Temperature Thermal Treatment LT3 Site Demonstration
Michael G. Cosmos, Roy F. Weston, Inc 71
Plasma Arc Vitrification
Richard C. Eschenbach, Retech, Inc 78
Thermal Desorption of PCB-Contaminated Waste at the Waukegan Harbor
Superfund Site (A Case Study)
Robert Shanks, SoilTech ATP Systems, Inc 90
The Babcock & Wilcox Cyclone Vitrification Technology for Contaminated Soil
J.M. Czuczwa, Babcock & Wilcox R&DD 119
HI
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The ECO LOGIC Process
DJ. Hallett, ELI Eco Logic International, Inc 129
BioGenesis"" Soil Washing Process Technology Summary
Charles Wilde, BioGenesis Enterprises, Inc 136
Steam Enhanced Recovery Process (SERP)
William R. Van Sickle, Hughes Environmental Services, Inc 142
Soil Venting to Remove DBCP from Subsurface Soil: A Case History
M.B. Bennedsen, Woodward-Clyde Consultants 146
5 Years Operational Experience with the Harbauer Soil Washing Plants
Winfried Groschel, Harbauer GmbH & Co. KG 161
Field Demonstration of Soil Washing at the King of Prussia Superfund Site
Michael J. Mann, Alternative Remedial Technologies, Inc 175
The Lurgi-DECONTERRA® Process Soil Washing
Ted J. Pollaert, Lurgi Corporation 192
Efficient and Cost-Effective Programs for Soils and Groundwater Restoration
J.J. Malot, Terra-Vac 200
Radiolytic Remediation of a TCE Ground Spill Using an Electron Accelerator
S.M. Matthews, Lawrence Livermore National Laboratory 206
Rethinking the hydraulic cage concept for hazardous waste disposal facilities
and mitigation of contaminated sites
Charles Voss, Golder Associates, Inc 212
Innovative Contracting Strategies for Equipment Procurement - Bofors Nobel
Superfund Site - Muskegon, Ml
Ted H. Streckfuss, U.S. Army Corps of Engineers 226
Remediation of Groundwater Contaminated with Volatile Organic Compounds
in the Saturated Zone at a California Superfund Site in Mountain View,
California
R.F. Battey, The Earth Technology Corporation 254
Soil Washing of Lead-Contaminated Soil at a Former Gun Club Site
Christine Parent, CAL/EPA Department of Toxic Substances Control .... 261
IV
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Improvements in the Conventional High Temperature Rotary Kiln Incineration
Technology
Markku Aaltonen, EKOKEM Limited 270
Evaluation of Grouting Technology: DOE Perspective
W. Roberds, Golder Associates, Inc 276
Du Pont/Oberlin Microfiltration Technology (SITE)
Ernest Mayer, E.I. du Pont de Nemours, Inc 296
Composting of Explosives-Contaminated Soil at the U.S. Army Depot Activity
Captain Kevin R. Keehan, U.S. Army Toxic and Hazardous Materials
Agency 313
United States/German Bilateral Agreement on Hazardous Waste Site Clean-Up
Projects
H. Stietzel, Federal Ministry for Research and Technology, Germany .... 324
Groundwater Remediation: Extraction and Removal of TCE & Cr6+ at an NPL
Site
Subijoy Dutta, U.S. EPA, Office of Solid Waste 340
The Use of Horizontal Wells in Remediating and Containing a Jet Fuel
Plume - Preliminary Findings
Mark Thacker, COM Federal Programs Corporation 346
Evaluation of Thermal Extraction Technologies for Treatment of Soils
Contaminated with Coal Tars and Wood Preservatives at the Pacific Place
Site, Vancouver, B.C.
Sandra Whiting, SCS Engineers 358
CF Systems' Solvent Extraction Technology for Site Remediation: A Post
"Site Demonstration Update"
Chris Shallice, CF Systems Corporation 373
Commercialization of Innovative Technologies - Challenges and Solutions
(A Technology Vendor's Perspective)
Frederic A. Eidsness, Jr., Canonie Environmental Services Corp 385
Bioremediation of Chromium (VI) Contaminated Solid Residues Using Sulfate
Reducing Bacteria
Louis J. DeFilippi, Allied-Signal Research and Technology 417
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ABR-CIS bioremediation : full-scale experiences with an in-
situ treatment system for sediment volume-reduction and
contaminant mineralisation in harbours and waterways
Author : ir. B. Malherbe
HAECON N.V., Harbour and Engineering Consultants,
Ghent, Belgium
ABSTRACT
The improvement of the in-situ natural microbiological degradation of organic matter
or organic compounds present a very attractive solution for the management of
(contaminated) sediments in harbours and waterways. To get efficient biodegradation
as much aerobic bacterial strains as possible have to be reactivated. This natural
biodegradation process is particularly interesting for the achievement of an in-situ
volume reduction of the deposit and/or in-situ decontamination of organic
contaminants. ABR-CIS (Augmented Bio Reclamation - Conditioning In-Situ) is such
an in-situ treatment technique which has been applied on full-scale. The projects
executed with the ABR-CIS system will be discussed and the monitoring results will
be presented. Moreover, the application of the ABR-CIS may represent major savings
with respect to the classical dredging and disposal costs.
The accumulation of mud deposits in aquatic systems goes often parallel with the
accumulation of organic micro-pollutants and nutrients and with eutrophication. This
causes problems for the management (disposal) of these sediments to be dredged for
navigation, calibration or even sanitation reasons.
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or
The "over-supply" of organic wastes in river-systems from sewers, domestic
agricultural effluents has caused a saturation of the natural biodegradation processes in
the aquatic environment (figure 1).
CONTAMINANT INPUT:
- ORGANIC COMPOUNDS
- NUTRIENTS
- OTHERS
ORGANIC MATTER INPUT:
-PLANCTON
- ALGAE
-LEAVES
- SEVWGES
IDECREASE OF OXYGEN-SUPPLY:
! - EUTROPHICATION
j - INCREASE OF VWTERDEPTH
' - FLOATING ORG. PRODUCTS
SEDIMENT ACCUMULATION:
- ANOXIC
- ENRICHED IN ORGANIC
MATTER
CONSEQUENCE: SLOW, UNCOMPLETE ANAEROBIC
BIO-DEGRADATION
Figure 1 : Mechanism of creation of saturated anoxic sediment deposits
During the search for a simple technique to re-activate aerobic mineralisation
processes, the ABR-CIS system was developed (ABR : Augmented Bio Reclamation -
CIS : Conditioning In-Situ).
This presentation goes through some elementary concepts in microbiological processes
to illustrate the potential of the ABR-CIS system which is an in-situ microbiological
treatment system of sediments.
The potentiality of ABR-CIS lies in a mineralisation of organic matter ( =
microbiological dredging) and a mineralisation of organic micro-pollutants ( =
treatment in-situ).
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BACTERIA AS PART OF THE NATURAL ECOSYSTEM OF
SEDIMENT DEPOSITS
Fine-grained sediments are deposited in a wide variety of aquatic environments. These
deposits, often called "muds", are a specific habitat for different organisms. The
specificity of mud habitats is related to the high accumulations in the deposits of
decaying biomass, adsorbed organic compounds, nutrients or man-induced
contaminants. The sediment is making part of the global aquatic ecosystem composed
of atmosphere, water column and sediment deposit. The typical aquatic ecosystem is
described by the trophic chains illustrated on figure 2.
Figure 2 : Description of ecosystem elements in aquatic environment
Micro-organisms, such as bacteria, are occuring in the atmosphere, the water column
and the sediment deposit (micro-benthos). On figure 2 it is clear that bacteria play a
fundamental role in the mineralisation of organic products in water and sediment.
Within the ecosystem bacterial activity is obviously related to the development and
activity of other organisms such as e.g. diatoms (Hamilton, 1987).
Types of bacteria occuring in mud deposits
The environment where mud is deposited is also favourable for the deposition of e.g.
dead phytoplancton (primary producers) or other fine-grained products. The presence
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in mud of the clay-humic complex stimulates particular physico-chemical and
biochemical reactions important to understand the environment of bacteria.
Bacteria are micro-organisms (diameter ca. 0,0001 - 0,02 mm). They are
systematically classified in 3 types (Vogel, 1970) :
1. Eubacteria (unicellular most common bacteria species) :
- coccae
- bacilli
- vibrionic.b.
- spirillic.b.
2. String bacteria (composed of micro-colonies interconnected with fibres).
3. Actinomycetes (sessile cells with radiating filaments).
Bacteria can also be classified according to the feeding function, i.e. :
autotrophic : assimilation of carbonic acid by photosynthesis or, more
commonly, by chemosynthesis of compounds present in the sediment or the
water ;
heterotrophic where the assimilation is done out of living or dead organic
matter; as such they are essential in the C- and N-cyclus between lower and
higher organisms.
The above mentioned classification suggests consequently that bacteria are essentially
food- and environment specific. In fact, the bacterial flora of sediments show a wide
range of adaptative variability relative to :
- the sediment texture related to the penetration of water, gases or even other
organisms ;
- the type and quantity of organic matter (governing the biodegradability or the
specific food) ;
- the bio-available oxygen content;
- the temperature;
- other organisms and their seasonal cycli (including respiration cycli) ;
- particular contaminants adsorbed to the mineral or organic mud particles and/or
with a toxicity vs. bacteria.
Bacteria are also classified according to their respiratory mode (aerobic and anaerobic
bacteria). In fact, the classification of bacteria according to the respiratory mode is the
best adapted to describe the bacterial ecosystem in aquatic and fine-grained
sedimentary environments. The reason for this is related to the relative low vertical
diffusion of atmospheric oxygen through the water column and the sediment deposit ;
all ecosystem equilibria are governed by this oxygen input which may be strongly
affected by a lot of external reasons, such as water circulation, agitation, water
depths, turbidity, dwelling organisms, ...
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Metabolism processes of bacteria
The above mentioned adaptative bacterial variability and heterogeneity related to the
cited factors is a function of the availibility through the water of essential chemical
components for bacterial growth , such as oxygen , nitrates , phosphates, sulphates,
etc. ... The biodegradation products of bacterial activity (E^S, ammonium, N2, CC>2,
H2O) are diffused back to the water column and the atmosphere.
The carbonic acid assimilation, which forms the basis of bacterial metabolism (by
photosynthesis or chemosynthesis) is done by resorption through the cell-membrane
(diffusion, osmose). To activate the assimilation, bacteria are secreting selective and
species - specific exoenzymes (biocatalysators) able to decompose and mineralize a
wide range of organic compounds.
Not only humic acids but also more complex organic chains such as phenols, PAH's ,
mineral oils, ... can theoretically be decayed by bacterial metabolism processes (fig
3).
CO, * H,0 — CH,-COOH ' —
Kzm.-a>-oen>e: *
OIO~A01PlNCZUUt
Figure 3 : Biodegradation process of naphtalene, a common PAH contaminant in
sediments
But not all organic matter is even bio-degradable and most of the mud deposits have a
lack of energy and nutrients to assure continuous bacterial activity and/or growth. The
important ecosystem cycli (e.g. diatom cycli) are of primary importance in bacterial
activity. The illustration of typical marine ecosystem cycli is illustrated on figure 4.
The spring and late-summer bloom of diatoms abundancy is clearly visible on this
diagram.
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These time cycli are important because the supply of nutrients and organic matter to
the sediment bed, the temperature and the available oxygen (from respiration or from
diffusion) will know large fluctuations. The micro-organisms will have to adapt
themselves to these fluctuations.
When living conditions are becoming worse, bacteria have interesting
defense/preservation modes, such as (Pommepuy et al., 1989) :
spore formation (formation of a thick-walled resistant spore) .
dwarfcell formation (formation of a small cell with limited metabolism) .
somnicell stage (the bacteria are putting themselves in a kind of lethargic state).
SEASONAL VARIATIONS > PRIMARY PRODUCTION
PHYTOPLANCTON.NUTRIENTS AND ILLUMINATION
j 2 r 3 L, 4 » 5 „ 6 j7j 8 ,9 8 10 o
12
PARAMETERS
NUTRIENTS DIATOMS ABUNDANCY
FLAGELLATE ABUND, "« DAILY ILLUMINATION
'DIAGRAMS ON RELATIVE SCALE
(from e«tl from WiterkwililtiUDil"
Noo'B«e 19EE i-c B "en 19891
Figure 4 : Ecosystem cycli related to primary production in marine environment
When growing conditions are becoming better the bacteria are reactivated from these
spores, dwarfcells or somnicells. The survival of the bacteria depends on their ability
to store energy reserves (e.g. in the form of glycogens).
Bacteria are able to improve the environmental conditions which they need to develop
their specific activities. They may adhere to sediment particles, to organisms or form
long chains of bacteria. This adhesion is done with polysaccharic fibres such as
glycocalix, which is secreted by the bacteria themselves. The glycocalix (Moureau
and Richelle - Maurer, 1990) has specific characteristics :
- it maintains bacteria on the substrate regardless current action ;
- it traps nutrients ;
- it retains the digestive exoenzymes ;
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- it forms a physico-chemical protection against toxins, virusses, antibiotica and
predators;
- it maintains appropriate physico-chemical conditions to allow bacterial growth and
activity.
Anyway, the survival time of bacterial population in sediments can be very long and
reach over several months to years (Rosack and Col well, 1987).
As for all living organisms and as mentioned before, the bioavailable oxygen is of
primary importance for bacterial metabolism life and growth. Therefore, by many
researchers, bacteria are rather classified according to their respiratory mode :
aerobic bacteria : bacteria which use free (dissolved) oxygen; degradation of
organic compounds is fast and complete (high burning efficiency) ;
anaerobic bacteria : bacteria which use chemically bound oxygen (no free
oxygen available): biodegradation is slow and incomplete.
Aerobic and anaerobic bacteria in sediments
When mud is deposited in an aquatic environment the oxygen supply to the sediment
deposit is limited because of several reasons :
mud is often deposited in water with slow water circulation and consequently
low dissolved oxygen contents (< 5 mg C>2/1) ;
the distance between the mud and the atmosphere increases (due to the presence
of the water column and the mud for increased water depths) ;
the mud has low permeability due to clay minerals and fine grains and
horizontal layering ; this decreases vertical oxygen diffusion ;
the presence in mud of high proportions of Fe-hydroxydes increases the COD
(chemical oxygen demand) ; in general the COD of mud deposits is high.
The main electron terminal acceptors used during the decomposition of organic matter
are in decreasing order of efficiency (Claypool and Kaplan, 1974) :
1. free oxygen;
2. nitrates;
3. sulphates;
4. (bi)carbonates.
This biochemical succession is accompanied by chemical reduction processes in the
sediment and, consequently, by a decrease of the redox potential, Eh (redoxpotential
as low as -350 mV).
This vertical layering in mud deposits has been schematised by Claypool and Kaplan
(1974) and is also illustrated on figure 5.
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F
PHASE OXYGEN SUPPLY BACTERIA £ft MINERALISATION
PRODUCTS
AIR
WATER
^\
SED1MEN
//
y.
RESPIRATION
•DISSOLVED OXYGEN AEROBIC BAG. + CO2/H20
FERMENTATION ^AcS? +/~
T OEN.TR.HCAT.ON °™™™« -
SULPHATE SULPHATE
nEPUCT,ON -=A "
BICARBONATE METHANE
„„„,„.,,«*, PRODUCING CH4/H20
REDUCTION BACTERIA
'igure 5 : Schematic presentation of bacterial layering in mud deposits
The natural vertical layering explains why most of bacterial activity in mud is
essentially anaerobic resulting thus in a slow and uncomplete degradation of organic
matter. The vertical bacterial layering will be analysed more in detail below
(Pommepuy et al., 1989).
The aerobic surface layer
This very thin layer is colonized by an abundant microbial flora (109-1010
bacteria/ml). Numbers decrease with depth because of the reduction of available
substrates (Atlas & Bartha, 1981). The bacterial population may represent from 0,2 to
2 % of the total organic matter (Meyer-Reil, 1984). The surface bacteria are mainly
Pseudomonas and Vibrio-gram negative bacilli along with other bacterial-types such as
Nirrosomonas and Nitrobacter, autotrophic bacteria which are responsible for
nitrification (oxidation of ammonium salts to nitrites and then to nitrates (Martin
1979).
Other organisms like Diatoms (Navicula, Nitschia, etc. ...) and blue algae (Spirulina.
etc. ...) are also proliferating in this aerobic surface layer especially if light is
penetrating as deep (Francis - Boeuf, 1949). Gen. Thiorodo bacterium may oxydize
sulphur compounds and is part of the sulphur cyclus (similar to the N-cyclus).
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In the presence of molecular oxygen, the surface flora use aerobic respiration to
breakdown organic matter; this type of respiration is most energetically efficient. In
this surface layer, aerobic bacterial production and decomposition of organic matter
are greatest and total organic carbon mineralisation (H2O/CO2 state) may occur.
There is intense floral competition for the utilization of released intermediate
decomposition products, and bacteria with the highest intrinsic growth rates are
favoured.
Fecal flora can settle at the same time as organic matter from anthropogenic
discharges. The main species found are fecal Streptococci and Enterobacters
Escherichia coli, Klebsiella, Salmonella. These latter bacteria are pathogenic and can
be dangerous for humans when contaminated shellfish are ingested. Hernandez (1985)
has recorded the presence of very high concentrations of fecal Streptococci in fine
harbour sediments.
Anaerobic levels
In the lower layers, there is an observed reduction in the number of bacteria and a
floral change , which may be partially explained by the appearance of gram-positive
bacteria genus Clostridium ... (Bianchi et al., 1977; Bensoussan et al. 1981). Bacterial
flora use either facultative or strict anaerobic respiration, or fermentative processes.
At all levels Ferrobacteria are occuring reducing the ferricompounds to ferro-
compounds and delivering the typical black color to reduced mud.
Fermentative bacteria
The genus Clostridium (spore-forming) may account for a major part of the strict
anaerobic fermentative bacterial population (Atlas & Bartha, 1981). These bacteria
play a major role in mineralisation of organic matter (cellulose, ...) since they are
capable of utilizing organic material which other bacteria have difficulties breaking
down, and also they synthesize exoenzymes which can hydrolyze many
macromolecules into small molecules that can be self-assimilated, or assimilated by
other micro-organisms (Marty et al., 1989). Spore Clostridia which are pathogenic
for man (Clostridium perfringens and possibly Clostridium tetani, Clostridium
botulinwri), are also found amongst these flora.
Denitrifying bacteria
Denitrifying bacterial numbers vary from 1C)4 to 10^ per gram of dry sediment (Jones,
1979). The Pseudomonas zndAeromonas strains are those most frequently isolated, as
well as some vibrobacteria. In fact it seems that we know very little about the
bacterial species involved (Heitzer & Ottow, 1976). For denitrification processes, the
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sediment must be anoxic, and there must also be nitrates in the underlying waters and
sufficient nitrate diffusion within the sediment. Two processes are involved in
denitrification : the first process includes catabolic reduction to transform nitrate
(NOs) into nitrite and into nitrous oxide (N20) and molecular nitrogen (N2). More
recently a second process has been discovered, which involves formation of an
ammoniumion (NH^) from nitrite by catabolic fermentation. Current studies have not
yet established whether or not this is a major phenomena. These two processes seem
to operate simultaneously but their importance varies according to the concentration of
organic matter. The percentage of nitrate transformed into ammonium was found to
vary from 20 to 12 % in previously studied sediments (Koike & Hattori, 1978).
Nitrobacteria and Ferrobacteria have wide varieties of species able to reduce
anorganic compounds.
Denitrification, which develops oxydation-reduction potentials that are higher than
those accomplished by sulphate reduction, takes place within the sediment above the
sulphate-reduction zone.
Sulphate reducing bacteria
In seawater, oxygen associated with sulphur, in the form of sulphate, is 200-fold more
abundant than molecular oxygen. Moreover, sulphate can be found deep within the
sediment (a few meters). In anoxic marine deposits, sulphate reduction is an important
phase in the mineralisation of organic matter (Marty et al., 1989). The abundance of
these sulphate reducing bacteria (classified in 7 genera Desulfobacter,
Desulfobacterium, Desulfobulbus, Desulfococcus, Desulfomonas, Desulfonema and
Desulfosarcina) is linked with sulphate availability and amounts of organic matter
(closeness to pollutant discharges). Their densities are estimated to be 10^-10^
bacteria/ml. These bacteria are involved in the final phases of organic matter
mineralization within anoxic sediments and could be responsible for 50 % of the
oxidation of organic carbon (Jorgensen, 1983), compared to 2-3 % for denitrification
(Fenche & Blackburn, 1979; Jorgensen, 1983).
The high activity of sulphate reducing bacteria in muds is also the cause of the typical
smell problems associated to waters with such sediment deposits.
Methane producing bacteria
At very low redoxpotential values the bicarbonate molecule is reduced by specific
bacteria to methane. Bicarbonate is available from coprecipitation from aquatic
plancton and necton deposits or from early diagenesis processes.
10
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Methane is produced e.g. in marsh areas and in the early petroleum-genesis processes
in mudstone.
Some interesting properties of bacteria
The above mentioned considerations show that bacteria, in good environmental
conditions of oxygen, nutrients, temperature, etc... can execute interesting actions to
serve man : mineralisation of organic mud or the clay-humic flocks (= microbiologic
dredging) and mineralisation of organic micro-pollutants (= decontamination
treatment in-situ).
It is important to notice some other particularities of bacteria :
at different development stages some bacteria may have plasma-filaments which
act as flagellae to execute displacements ; however, most of bacteria are sessile
organisms ;
in good environmental conditions bacteria multiply by cell (mitosis) ; each 20-
40 minutes bacteria may divide (1 organism can deliver ca. 248 successors in 24
hours) ;
the small dimensions of bacteria facilitate the dispersion ;
in contact with toxic substances bacteria secrete organic acids or produce
metabolic products, causing a bio-leaching.
Bio-leaching of metals is a well-known phenomenon used in mining (Cu, Co, Au ore
extraction), in mineral valorisation or in corrosion protection. All metals in the
aquatic environment are susceptible to microfouling by bacteria, protozoa and algae.
Regarding corrosion, bacteria are thought to be responsible for ca. 50 % of the
failures of buried pipelines and cables.
CONTEXT OF MODERN AQUATIC ENVIRONMENTS VS.
THE ABR-CIS TREATMENT METHOD
It is now obvious that the early 60's idiom "The solution to pollution is dilution" is a
bad and non-appropriate management rule regarding the protection of aquatic
environments. The large supply of nutrients to surface water systems combined with
the input of organic-rich and contaminated effluents has caused the well-known
problems of eutrophication contamination of water (direct) and contamination of
sediments (Indirect).
The problem is complex because phenomena like eutrophication and desequilibria in
oxygen-balance is also linked to the decrease of light penetration due to turbidity
increase. Turbidity increase may itself be caused by unappropriate agricultural sand-
11
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use ( increased run-off of fine sediments), over-saturation by organic compound
effluents (floating at the surface of the water) and/or other man-related activities
(dumping, dredging, ...) .
Eutrophication is a situation where the aquatic system has an over-abundanccy of
nutrients such as phosphates and nitrates, and where the natural biodegradation
process by micro-organisms has become over-saturated. The direct effect of
eutrophication is oxygen depletion and important deficits in oxygen supply. This
oxygen deficit is most important in the deeper parts of the water column and in the
sediment deposits. Indirect effects are e.g. specific and intense algae blooms,
reduction of diversity and abundancy of aquatic organism species, bad smell and other
unattractive phenomena affecting the aquatic system.
Phosphates can be treated in-situ by Ca-rich compounds or FeCl3 (precipitation).
Such treatment precipitates the phosphates to poor-soluble salts. Nitrates are difficult
to combine into insoluble compounds. The problem with nitrates and phosphates is
also the diffuse input into surface waters (from many small effluents or from run-off).
The only efficient treatment method of organic and anorganic contamination of
aquatic systems is the tackling at the source, i.e. the strong reduction or prohibition of
effluents.
Muddy sediments tend to accumulate and concentrate all kinds of organic and
anorganic contaminants from the water column through different mechanisms :
- adsorption of contaminants to humic-clay complex or Fe-compounds
- ion-exchange to clay particles (heavy metals) ;
- co-precipitation ;
- accumulation through plancton deposition.
Consequently, highly industrialised countries face serious problems of environmental
protection of the aquatic system due to the contamination of water and sediments.
Regarding the sediments the problem becomes accute because :
1. canals, waterways and rivers have to be maintained at a given (artificial ?)
design profile to ascertain safe navigation, to prevent floodings or even for
sanitation reasons (smell, pollution, ...) ; the dredged quantities to be disposed
(on land or in aquatic system) are quite important with respect to the available
disposal capacity : there is a lack of disposal facilities resulting- in drastic rise of
disposal prices (upland disposal fee in 1990 up to 80 U.S. $/m3) ;
2. industrial treatment of the sediments is generally considered as unfeasible due to
(high) treatment costs, due to low treatment production rates and to too specific
treatment methods with low efficiencies.
These facts have lead to the development of in-situ microbiological treatment methods
where the natural indigeneous bacterial flora is used and stimulated to obtain the
following :
12
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a) mineralisation of organic matter resulting in microbiological dredging ;
b) mineralisation of organic contaminants by treatment in-situ ;
c) re-establishment of normal oxygen balances in the whole aquatic system.
This experimental research has led to the development of ABR-CIS.
Optimum conditions to re-activate normal bacterial degradation processes
The transformation of organic products into basic minerals such as CC>2 and H20 is
efficiently done by aerobic bacterial degradation. From the previous chapters it
appears how the normal biodegradation processes may be inhibited, i.e. essentially by
oxygen deficits.
To re-activate the desired aerobic biodegradation one should work to get optimum
conditions in the sediment deposit i.e. :
- oxygen supply in very dispersed and very bio-available way, to allow fast
metabolism and population growth,
- temperature : bacteria are active above ca. 8°C ; the higher the temperature (up to
30-40" C) the greater the bacterial activity ;
- season : the season is important in relation to temperature and ecosystem cycli ;
- toxicity : no toxic elements to bacteria should be present in the environment;
- organic matter : type and quantity of organic matter is important for optimal
aerobic biodegradation ;
- specificity and mutant population : for particular contaminants it is important to
assure complete biodegradation without formation of toxic intermediate products.
Augmented Bio Reclamation (ABR) - Conditioning In-Situ (CIS)
The ABR-CIS-system (Augmented Bio Reclamation - Conditioning In-Situ) is a joint
effort of the companies Ebiox A.G. (Sursee, Switzerland), EMR b.v.b.a. (Ghent,
Belgium) and HAECON N.V. (Ghent, Belgium).
ABR micro-organisms are extracted and isolated from the sediment. Thereafter they
are cultured on carbon substrates, similar to the target contaminants to be treated. The
ABR micro-organisms are then grafted on wood chips for transport. ABR is a
development and a trade mark of the company Sybron.
ABR micro-organisms are aerobic and the strains are selected in order to achieve an
as complete mineralisation of the contaminants as possible.
Conditioning In-Situ, CIS is a technique in which carefully selected and blended
natural mineral products are injected into the sediment deposits. The CIS products are
rich in free and bio-available oxygen (porous structure) and supply the ecosystem with
the required oligo-elements and nutrients. CIS is stimulating and re-activating all
13
-------
indigeneous natural aerobic bacterial activity causing an increased biodegradation of
the undesired sedimentation products in the aquatic system. CIS products are
guaranteed to be harmless to components of the aquatic trophic chain, including man.
ABR-CIS is designed to be a microbiological in-situ treatment technique of organic
muddy sediments contaminated with particular organic biodegradable micro-pollutants
BTX and derivates ;
mineral oil and compounds
PAH's ;
phenols, formaldehydes;
pulp, cellulose, starch, proteins, fats ;
Process of ABR-CIS treatment
Each project is first analysed on the microbiological treatment of the mud sediments
and the organic contaminants. Therefore samples of the sediments are cultured in the
laboratory and microbiological proliferation is monitored with respirometer-testing
(oxygen uptake) and total resp. selective plate counts. When the treatability of the
mud is confirmed the ABR-CIS treatment is designed (dosage, type of bacteria,
injection scheme, ...).
The treatment process is executed as follows :
1. culture of ABR micro-organisms ;
2. blending of CIS-conditioner ;
3. mixing, drumming and transport of ABR-CIS powders ;
4. dilution and aeration of ABR-CIS powder with water of the waterway ;
5. injection of ABR-CIS suspension in the sediment by using adapted dredging
equipment or high pressure jetting ;
6. monitoring of the sediment-level and sediment-quality.
Up till June 1992, 7 ABR-CIS full-scale projects have yet been executed on industrial
scale. Volumes ranging between 100 m3 and 5.000 m3 have been treated in-site and
monitored during 12 to 20 months after injection.
Reasons for applying in-situ treatment are related to :
a) volume-reduction of the sediment (and avoiding upland disposal) ;
b) decontamination of mineral oils and/or PAH's.
14
-------
RESULTS OF MICROBIOLOGICAL TREATMENT OF
SEDIMENTS
To evaluate the efficiency of ABR-CIS treatments this last chapter will focus on some
projects already executed and the treatment results obtained.
Re-establishment of oxygen balance
The best way to measure the physico-chemical and biochemical status of a sediment
deposit regarding oxygen balances in the determination of the redox potential, Eh. It
has been stated previously that anaerobic conditions are associated to reducing
conditions, i.e. with negative Eh.
REDOXPOTENTIAL Eh (mV)
100
60
-60
-100
-200
ABR/CIS
OXYDATION |
-2SO
LJI
REDUCTION
34
0:00 04 41 1:53
DAYS (cfr. ABR-CIS-treatment)
2:24
4:10
Figure 6 : Evolution of redox potential in mud deposits after ABR-CIS treatment
(project Zonh.)
Shortly after ABR-CIS treatment the black reduced mud deposit is changing to mud
with neutral or even positive Eh-values. This is illustrated on figure 6 where Eh
values measured on the field show a quick evolution from ca. -200 m V to positive /
neutral values.
15
-------
Improvement of microbiological activity
The oxygen input by CIS allows the ABR and indigeneous bacteria to proliferate. This
is measured by taking samples at regular time intervals and by measuring the total
plate count.
This is illustrated on figure 7 where the strong increase in total plate count after
treatment can be seen.
Volume reduction of sediment deposit hy mineralisation
The biodegradation of organic matter in the mud deposit causes a volume reduction of
the sediment deposit (mineralisation of organic matter and/or disruption of the mud
flock-structure). This can be seen on comparative sounding-diagrams. This is
illustrated by cross-sectional soundings of waterways in which the sediment deposit
was treated with ABR-CIS. Figure 8 shows the volume reduction of the sediment
deposit in a small freshwater river where ABR-CIS was applied (project
Krimpenerwaard, The Netherlands, project ordered and executed in collaboration with
Consulmij B.V.).
TOTAL PLATE COUNT (CFU/g.dry »olid)
1,0006* 11
VOOOE-10
1.000E-09
ABR/CIS,
roooE-oe.
10000000 • — — •• -----
1000000 > '
10000 '
"--^
*r ,
•:
c
&* V-
—
_^__
1
i i!
I 1 i
28/6/901-8) S/9/»0(To) 8/10/90<«33) 14/11/901*70)
DATE OF SAMPLING (days w.r.t To)
Figure 7 : Increase of total plate count (TPC) after ABR-CIS treatment
16
-------
DEPTH (m)
0.6 r^
-0.6
-••
•1.6
23466
DISTANCE ALONG CROSS-SECTION (m)
DESIGN PROFILE
DATE OF SURVEY
•*-08/05/91 -8- 24/06/91
•22/07/91
Figure 8 : Volume reduction of sediment deposit after ABR-CIS treatment (project
Krimpenerwaard, the Netherlands)
A global volume reduction of ca. 50-60% of the original volume has been realized by
this microbiological dredging. Figure 9 shows a simular cross-secitonal view with
sounding results at different time intervals showing the progressive volume reduction
of the sediment deposit in a brackish/fresh water canal (Bakhuistervaart, the
Netherlands, project ordered by J. Klip B.V.).
DEPTH ( m NAP)
-0.8
-1.3
-1.8
-2
4 6 8 10 12 14
DISTANCE ALONG CROSS-SECTION (m)
16
18
20
DESIGN PROFILE
8/08/90
SOUNDING DATE
24/04/90
21/09/90
14/06/90
Figure 9 : Volume reduction of the sediment deposit after ABR-CIS treatment over
the whole deposit thickness (Bakhuistervaart, the Netherlands)
17
-------
On figure 10 the reference cross-sectional profile of the Bakhuistervaart is shown to
analyse the natural volume-evolution of the sediment deposit when this is not treated.
DEPTH I m NAP)
| NON-TREATED REFERENCE SECTION
i e » 10 12 14 ie IB 20
DISTANCE ALONG CROSS-SECTION (ml
DATE OF SURVEY
-24/04/80 -H-11/07/BO
-B/00/80 I
Figure 10 : Result of sounding survey of the canal in a non-treated section
(reference section).
A global volume reduction of ca. 50% has been realised in ca. 18 months.
Biodegradation of organic compounds
For the Bakhuistervaart project 3.100 m3 of sediments were heavily contaminated
with mineral oil (2000-3000 ppm). After ABR-CIS treatment (18 months after
injection) the mineral oil content had significantly decreased down to acceptable legal
levels (fig. 11).
MINERAL OIL CONTENT (1000 no/kg
-------
A similar in-situ biodegradation of mineral oil has been obtained in the Park River
(project Edegem ; figure 12) and the Westeindse Waterweg (project Zoeterwoude,
ordered by and executed with Consulmij B.V. ; figure 13).
MINERAL OIL-CONTENT (1000 me/kg d.m.)
3/28
4/4 4/30
DATE OF SAMPLING (month/day) 1990
e/S
LOCATION SAMPLES
(SAMPLE NR. 1 SOUTH H3 SAMPLE NR. 2 CE NTER
Figure 12 : Biodegradation of mineral oil in Edegem Park River (Belgium)
MINERAL OIL CONTENT (1000 mg/kg d.i.)
ABR/CIS
«
fc\S
fcr.
1 '-J
••.% ,
!* '\, -
&-
?;t
\..S',,
*••
hi
24/06/81
1
3IT-1
Hi
30/07/91 03/08/91 06/11/91 Ott/12/91
DATE OF SURVEY
SAMPLING LOCATION I
EDSAMPLE NR. 1 ^SAMPLE NR. II 1
Figure 13 : Biodegradation of mineral oil in Westeindse Waterweg (Zoeterwoude,
the Netherlands).
19
-------
In the Zoeterwoude project a significant contamination with PAH's occured as well
(major PAH's : Fluoranthene, Pyrene).
On figure 14 the global evolution of the contaminant-content is shown illustrating the
progressive biodegradation of the considered contaminants although less spectacular
than with e.g. mineral oil content. Some fluctuations occur in the detected PAH levels
; these are supposed to be caused by analytical uncertainties, sample representativity /
reproducability and release due to microbiological action.
TOTAL PAH CONTENT (mo/kgd.m.)
ABR-CIS
In
"
,11
i
•".
-
I . 1}
1
• i i , I
1 rn
i , ,
14/0t 30/07 lot 03/09 /10 04/11 /I! /01 /02 /03 14/04 /OC lOt IJ/07
1991 DATE OF SAMPLING 1992
SAMPLING LOCATION
tm BLANCO BCO L7J MONSTER SCO 1 D MONSTER BCO 2
•• BLANCO RIJNLANO 1 1 MONSTER RIJNLAND 1-2 dl MONSTER RIJNLANO 3'4
Figure 14 : Biodegradation of PAH's in the mud of the Westeindse Waterway
(Zoeterwoude, the Netherlands).
Further additional scientific research is necessary however to analyse the exact
biodegradation process and the variations in adsorption of contaminants to the clay-
humic complex.
ABR-CIS process costs
The project preparation product and injection costs for a typical ABR-CIS project
range between 20 and 30 U.S.S par m3 of sediment in-situ to be treated. When a 50%
volume reduction is achieved by microbiological ABR-CIS dredging, the cost of the
dredging of 1 m3 will consequently range between 40 and 60 U.S.$.
These costs must be compared with the classical dredging and disposal costs (for
contaminated sediments) :
20
-------
dredging
dewatering
disposal
total
ca. 15 U.S.$/m3
ca. 60 U.S.$/m3
ca. 80 U.S.$/m3
ca. 155 U.S.$/m3
This has been confirmed by different cost/benefit calculations executed by the
managers of the waterways treated with ABR-CIS.
In the Bakhuistervaart project the municipality has officially declared that the
application of ABR-CIS system represented a saving of ca. 70% with respect to the
classical approach of dredging and disposal.
LITERATURE
CLAYPOOL G.E. and I.R. KAPLAN, 1974. The origin and distribution of methane
in marine sediments. Mar. Sci. 3 : pp. 99-139.
FENCHEL T. and T.H. BLACKBURN, 1979. Bacteria and mineral cycling.
Academic Press.
DE MEYER Chr., MALHERBE B., DE VOS K., 1992. ABR-CIS Bioremediation
for in-situ treatment of sediments. Proc. Forum for Applied Biotechnology,
FAB '92, Brugge 24-25.09.92.
FRANCIS BOEUF Cl. and BOURCART J., La Vase, Revue Scientifique, Paris,
1942.
JONES J.G., 1979. Microbial nitrate reduction in freshwater sediments. J. Gen.
Microbiol. 115 : pp. 27-35.
MARTIN Y. et BONNEFOND J.L., 1986. Conditions de decroissance en milieu
marin des bacteries fecales des eaux usees urbaines, Oceanis 12, Fasc. 3 : pp.
403-418.
POMMEPUY M., GUILLAUD J.F., LEGUYADER P., DUPRAY E., CORNIER
M. The fate of the bacterial load of dredged sediemnts. Proc. of Int. Seminar on
the Environmental Aspects of Dredging Activities, Nantes (Fr.) 27/11-01.12.89.
ROSZAK D.B. and COLWELL R.R., 1987. Survival strategies of bacteria in the
natural environment. Microbiol. Reviews 51 no. 3 : pp. 365-379.
21
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In Situ Bioventing of a Diesel Fuel Spill
T.L.Bulman, Manager Consulting Services, Campbell Environmental
M. Newland, Environmental Control Engineer, Campbell Environmental
6 Gould St
Osborne Park
Western Australia 6017
A.Wester, Industrial Chemist, Westrail
Montreal Rd East
Midland
Western Australia 6056
A diesel fuel spill occurred at a state rail yard late in 1989. The leak occurred
from a corroded buried pipe leading from an above ground tank. Fuel accumulated at the
surface of a shallow (2.5 m) unconfmed aquifer comprising sand and silty sands of the
Guildford formation. An area near the storage tank of 2000 m2 and over a depth of 1.5
to 2.5 m was contaminated with fuel. A total of 135,000 L of fuel was recovered using
oil skimmers in groundwater drawdown wells. An estimated 50,000 L (approximately
1.5% w/w in soil) remained in situ, smeared in the areas of drawdown wells to a depth of
3.5 m.
The potential for active and passive in situ bioremediation was explored through
laboratory assessment of oil mobility and biodegradation rates and field assessment of
contaminant distribution and groundwater flow. Oxygen supply was identified as the
factor most limiting biodegradation of the hydrocarbons, while the rate of degradation
was further increased by supply of the nutrients nitrogen and phosphorus. Although the
groundwater flow velocity achievable under drawdown conditions was rapid (2 x 10~3
cm/sec) it would require many years to supply sufficient oxygen in situ to effect
bioremediation. In contrast, supply of oxygen (as air) to unsaturated aquifer material was
predicted to achieve bioremediation in approximately 18 months.
A plan for remediation was designed in which the contaminated area was
dewatered, oxygen was supplied via air extraction from cased bores slotted throughout the
contaminated zone and nutrients were supplied via a micro-irrigation system. A pilot
scale remediation on one quarter of the site is currently underway to confirm rates of
degradation achievable in the field. Progress to date has indicated hydrocarbon reductions
of 2000 to 4000 mg/kg (10 to 30%) in the unsaturated soil to a depth of 3 m over a six
month period of venting only. Dewatering in the 3 to 3.5 m zone, however, was
incomplete and subject to fluctuating water levels. A further reduction averaging 30%
took place over the subsequent six months of venting and nutrient addition and extended
to the 3.5 m depth. Further investigations to be carried out during the pilot period
include 1) an evaluation of the efficiency of oxygen supply via vacuum or air injection, 2)
the fate of nutrients in unsaturated and saturated zones, 3) extent of remediation in the
unsaturated and saturated portion of the contaminated area.
Keywords: in situ bioremediation, bioventing, hydrocarbon contamination
22
-------
INTRODUCTION
A major diesel spill from a fuel line at the State Railway (Westrail) Marshalling
Yard occurred in 1989. The spill resulted in migration of fuel through a storm water
drain to the Perth Airport Southern Main Drain, necessitating immediate cleanup action
along a 3 km length of the drain. Further investigations on the Westrail site itself
revealed an area near the storage tank of approximately 2000 m2 and over a depth of 1.5
to 2.5 m was contaminated with fuel (Figure i). Fuel recovery operations were
immediately put into effect and options were explored for complete remediation of the
site.
ELECTRICAL
STORM DRAIN
• monitoring bore
O bore (discontinued)
pumping bore
10 m
ROAD
Figure 1 Site Plan of Spill Site at Westrail Forrestfield Marshalling Yard
23
-------
Due to the number of buried services and above ground tanks in the spill area, the
proximity of a carriage shed in full use and the low slope stability of site soil, excavation
was considered undesirable for remediation of the site. The potential for active and
passive in situ bioremediation was explored through 1) site investigations of diesel
concentrations, soil and aquifer characteristics, 2) laboratory assessment of oil mobility
and biodegradation rates and 3) pilot scale evaluation of in situ bioventing. Having
collected information in laboratory and field trials, it was desired to determine if
commercially available bioremediation models would be useful in designing full scale
remediation.
SITE DESCRIPTION
SPILL DELINEATION
An initial survey to determine the extent of contamination was performed by the
Geological Survey staff of the Western Australian Department of Mines. A total of 29
holes were augered to a depth of 4 to 5 meters. Soil was recovered for analysis from
above the water table at 1.8 to 2.5 m. Soil samples could not be recovered from the
saturated zone as the sand could not be held in the core barrel. The soil samples
consisted of 2.25 m coarse to medium sand fill over Guildford Formation sediments of
silty sand. Clayey sand lenses were intersected in 5 boreholes at a depth of 4 to 4.5 m.
Each borehole was lined with slotted PVC pipe for future use in water sampling.
A total of 280 soil samples were analysed by Westrail staff and indicated a well
defined contaminated area extending in a radius of 20 to 25 m from the source of the spill
(approximately 2000 m2) from a depth of 1.5 to 2.25 m (average thickness 0.75 m). Oil
concentrations ranged from 0.01 to 10% w/w.
Free product recovery was implemented on the site through trenching and
installation of soak wells, and finally through installation of four drawdown wells supplied
with skimmer pumps.
Following recovery of approximately 135,000 L of free product, removal
efficiency was reduced to approximately 1 L/day. At this point a second set of soil cores
were collected to determine the content of fuel remaining in the soil and to collect
samples for laboratory treatabiUty testing.
24
-------
AQUIFER CHARACTERISATION
The initial site survey performed by the State Geological Survey in March 1990
described an unconfmed aquifer of coarse to medium sand with clayey lenses at 4 to 4.5
m depth. The depth of the aquifer, based on regional information, was estimated at 20
m. The natural hydraulic gradient across the site was 0.003 m/m. Subsequent intact
cores collected in August 1990 following recovery of free product identified bulk densities
ranging from 1.5 to 1.8 g/cm3, porosities of 0.28 to 0.44 and oil contamination of 1.5%
w/w in the 2 to 2.5 m depth and 2.5% w/w in the 2.5 to 4 m depth.
Pumping tests were performed during installation of the drawdown wells. These
wells were fully slotted over a 12 m depth. The depth averaged hydraulic conductivity
which was measured using these wells was 3 x 1Q4 to 2 x 10~3 cm/sec.
To evaluate the practicality of an injection/withdrawal method of bioremediation, a
field tracer test was conducted during continued water drawdown pumping. The test was
performed by injecting 1500 litres of a solution of 100 mg/kg Li as LiCl. The
concentration of Li was subsequently monitored in all monitoring wells on the site over a
21 day period. Concentrations of Li in groundwater were used to estimate the rate and
direction of groundwater movement under drawdown conditions. Under these conditions
the average gradient from the point of injection to the drawdown well was 0.1 m/m.
Discrete flow directions, however, were observed with differing flow velocities. Flow
circumvented the contaminated zone with velocities of 1.5 to 4 x 10"3 cm/sec, in
preference to the direction of the drawdown well in the contaminated zone which had a
velocity of 2 x 1CT* cm/sec.
TREATABILITY TESTING
SHAKE FLASK TESTS
Preliminary screening experiments were conducted in shake flasks using treatments
of either water or nutrient solution under aerobic and anoxic conditions. These trials
demonstrated that aerobic conditions with added nutrients resulted in the greatest rate of
microbial growth and concurrent hydrocarbon degradation. Very limited degradation
occurred under anoxic conditions, even with nutrient supplementation. Results from trials
with nutrient and oxygen supplementation and the control treatment (no oxygen or
nutrients supplied) are illustrated in Figure 2. These trials confirmed that native soil
organisms were capable of degrading the diesel, however oxygen and nutrients were
limiting to degradation.
25
-------
400
•3 300
s
rt
4-1
o
a
o
,0
u<
rt
O
o
•o
>,
200
100
control
oxygen and
nutrients supplied
10
15
20
25
time (days)
Figure 2 Results of Shake Flask Tests for Biodegradability of Diesel
Product With and Without Supply of Oxygen and Nutrients
COLUMN TESTS
Oxygen supply, in particular, was a problem in subsequent trials using saturated
soil columns supplied with a flow of well aerated water. Columns were set up to
simulate a control (water flow only) and supply of oxygen and nutrients in water at a rate
designed to simulate field conditions. Column flow rates and effluent nutrient
concentrations were monitored on a daily basis. Flow was initially restricted but
increased as oxygen and nutrient utilization increased. Over the length of the 60 cm
column roughly 50% of the added N, 80% of the added P and almost all supplied oxygen
was consumed. An encouraging increase in microorganism numbers was also noted. No
degradation of hydrocarbon was detected, however, within the 8 week study. The initial
diesel contamination of the soil was very high (15000 mg/kg) and the amount degraded
according to stoichiometric calculations (60 mg/kg) was well within experimental
uncertainty.
Trials were also conducted under unsaturated conditions in which a drip irrigation
system supplied nutrients and kept the soil moist. Microorganism counts increased 1000
fold within a few weeks and 20% of the residual hydrocarbon was degraded after 4
weeks.
26
-------
Calculations based on the stoichiometric amount of oxygen required to totally
mineralise the residual hydrocarbon content in site soil supported the results of the
column tests. Based on an assumed carbon content of 85% in the hydrocarbon,
approximately 3.5 mg of O2 would be required to mineralise 1 mg of hydrocarbon. On
the basis of measured hydrocarbon concentrations of 1.5%, supply of oxygen at a
solubility limit of 8 mg/L in water, would be insufficient to mineralize substantial
hydrocarbon in site soil within a manageable time period. In contrast, supply of oxygen
in the air phase, at a concentration of 20% by volume, would support degradation of the
hydrocarbon in site soil within 1 to 2 years.
These studies confirmed the presence of indigenous petroleum degrading
organisms. In view of its history as a fuel storage area this was not unexpected. Oxygen
and nutrients are limiting degradation, however, under field conditions. Residual diesel
concentration on the site was very high after recovery of free product. Consequently
bioremediation requires a significant supply of oxygen to meet the demand for total oil
removed. It is evident that groundwater flow through the site would make saturated phase
supply of oxygen impractical. Remediation under unsaturated conditions with supply of
oxygen through vented air was therefore viewed as the most practical approach.
PILOT TEST PERFORMANCE
OBJECTIVE
A six month pilot scale remediation was designed involving dewatering one quarter
of the site and encouraging in situ bioremediation through bioventing. The primary
objective of the pilot trial was to confirm the effectiveness of nutrient supply and
bioventing to meet proposed remediation criteria for diesel of 1500 mg/kg. The extent of
remediation was to be determined by periodic monitoring of soil for hydrocarbon
contamination and monitoring of groundwater for hydrocarbon and nutrients. A second
objective was to provide sufficient data on rates of oxygen uptake and hydrocarbon
degradation for calibration of the VIP and BIOPLUME II models. These models would
then be used to predict hydrocarbon loss for a full scale bioremediation design involving
the saturated and unsaturated zones. The design would subsequently be tested in full
scale remediation.
DEWATERING
The natural groundwater table resided at 2 to 2.5 m below grade, with seasonal
variation within that range. This was depressed by the weight of diesel in the
contaminated area and through generation of cones of depression to facilitate diesel
recovery. As a consequence, residual contamination was smeared within the 1.5 to 3.5 m
zone. Dewatering for bioventing of this zone was carried out to a designed depth of 3.5
m via electric submersible pumps installed in three shallow wells spaced around the
27
-------
northeast corner of the site (Figure 3). These wells are also supplied with skimmer
pumps for recovery of any additional oil which becomes mobilised and collects in the
wells as a result of dewatering. The deep (12 m) recovery wells and skimmers have also
continued in operation.
06WATEF1ING WELL
CARRIAGE SHED
PEWMNENT
M3NITORING WELL
BLOWER
DIRECTION OF NATURAL
GROUM)WAT6R FLO*
AIR MANIFOLD
AIR EXTRACTION WELL
PILOT WORK AREA
SCALE:
Figure 3 Schematic Diagram of Bioventing Pilot Trial - Plan View
Intermittent failure of one or more of the groundwater extraction pumps has
resulted in a fluctuating water table between 3 and 3.5 m depth for the first four months
of the pilot study. This problem was compounded by water entering the venting system
and tripping out the air extraction exhauster.
AIR SUPPLY
Soil aeration has been performed via air extraction from 9 bores installed to 4 m
with 50 mm PVC casing slotted between 2.5 and 4.5 m bgl (Figures 3 and 4). A coarse
sand filter pack was installed around the slotted interval with a bentonite seal to the soil
surface. The wells are joined to a valved and instrumented PVC header system
connected, through a moisture "knock-out pot", to the suction side of a small blower.
Exhaust is direct to atmosphere.
28
-------
GPOUNDWATER
NUTRIENTS
DIESEL CONTAMINATION
NUTRIENT FLOW
Figure 4 Schematic Diagram of Bioventing Pilot Trial - Section View
Influx of air is facilitated by the existing fully slotted monitoring and drawdown
wells, as well as exposed soil surfaces. Trenches which were used for free product
recovery have been back filled and provide zones of high permeability for air flow. A
vacuum of less than 2 kPa has been measured at all air extraction wells during continuous
operation. All wells are in an area of the site which is not sealed (i.e. no asphalt or
concrete cover).
Dewatering problems have resulted in intermittent function of the aeration system
over the first four month period. A strong hydrocarbon odour was initially evident in the
exhausted air, which has decreased with time.
The area of influence of the air extraction bores has been assessed by applying a 3
to 5 kPa vacuum to each well separately and measuring vacuum pressures in the other
wells. Vacuum pressures of approximately 20 Pa were measured at radii of 3 to 4 m
from the source well. Well spacing and configuration at final scale will be optimized
based on these results.
29
-------
NUTRIENT MOBILITY
The supply of nutrients to the study area was delayed and began six months after
initiation of site dewatering. Nitrogen and phosphorus are supplied through a drip
irrigation system installed 15 cm below the soil surface. Stock nutrient solution is
prepared using potable water and is added to recovered groundwater via a dosing pump
for irrigation. Addition of nutrient solution is adjusted to balance the uptake rate of
nutrients and maintain a soil moisture content of approximately 60 % of the water holding
capacity.
To date the mobility of nutrients has been monitored in groundwater only. Three
new monitoring wells fitted with dedicated bladder pumps were installed down-gradient of
the site ..(Figure 3). Groundwater concentrations of nitrogen or phosphorus measured
down-gradient of the site have demonstrated no response to nutrient addition levels. It is
planned to install soil pore water monitoring devices to collected additional data on
nutrient availability in order to better estimate uptake rates occurring in the field and
allow better optimization of nutrient addition.
OXYGEN UPTAKE
The rates of oxygen uptake in the unsaturated zone were monitored towards the
end of the six month pilot trial (July 1992). A total of 15 holes were hand augered to the
capillary zone (3 to 3.5 m) along transects through the pilot study area, with varying
distance from the air extraction wells, and into the uncontaminated and unremediated
portions of the site. Soil samples were collected from all locations. In 10 locations,
samples were taken at several depths. PVC probes fitted with soil oxygen sensors (Jensen
Instruments) were installed in all locations. To date, oxygen consumption has been
assessed at 4 locations, including in the uncontaminated and contaminated unremediated
areas of the site. Initial oxygen readings were recorded (during venting). The blower
was then turned off and oxygen concentrations were recorded over a period of 2.5 hours
and 3 days. The rate of oxygen consumption was assessed as the decrease in oxygen
content over time. Initial concentrations and rates of oxygen uptake are provided in
Table 1 with the measured hydrocarbon content. High hydrocarbon concentrations
correspond to high initial oxygen uptake rates to a maximum of approximately 2.5
%/hour. Uptake rates did not correspond to initial oxygen concentration.
30
-------
Location
unremediated
#11 (2.8m)
uncontaminated
#2 (2.8 m)
pilot area
#4 (2.8m)
(2.5 m)
#5 (2.8 m)
(2m)
(2.5 m)
DOC0
(%)
1
11
22
21
22
21
21
DO Rate0
(%/hr)
-0.4
-0.429
-2.43
-2.4
-2.49
-0.686
-1.37
Diesel
(mg/kg)
3800
0.2
3600
na
7700
0.2
860
Microbial Number
(CFU/gram)
9 x 102
4x 102
8x 103
8x 103
8x 103
5 - 70 x 103
8x 103
Table 1. Diesel concentrations, microbial numbers and initial oxygen concentrations and
uptake rates measured during bioventing pilot trial
DIESEL CONCENTRATIONS
Diesel concentrations in soil are currently available for five monitoring periods.
The first three periods were prior to the pilot study, as follows; 1) prior to free product
recovery (March 1990), 2) following recovery of most free product (September 1990), 3)
immediately prior to the pilot test (June 1991). The last two monitoring periods included
4) following six months venting but prior to nutrient supply (January, 1992) and 5)
following six months of both nutrient supply and bioventing (July, 1992). Cores taken
following free product recovery were located according to distance from drawdown and
oil recovery wells. Those taken following the initiation of venting were located according
to distance from the air extraction wells.
31
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35000
MONTHS
Figure 5 Average Trend of Diesel Concentrations in Pilot Trial Area
During Product Recovery and Bioventing Operations
The trend of overall concentration (averaged over depth and location) with time is
illustrated in Figure 5. The line illustrated has been fitted to all data using a distance
weighted least squares smoothing routine (SYSTAT). The majority of the decrease in
concentration (55%) occurred over the period of free product recovery of 15 months. A
further 13% decrease occurred over the following 6 months, during the period of
dewatering and venting. During the subsequent 6 month pilot trial period (venting and
nutrient supply) hydrocarbon concentrations decreased by 18% of the original
concentration, or 50% of the concentration remaining after free product recovery.
This decrease in concentration is not consistent over the site, however. The
concentrations measured at specific depths are illustrated in Figure 6 for the four
sampling periods during remediation of the site. A distance weighted least squares
routine was used to illustrate average trends in hydrocarbon concentration with depth.
The initial spill was located in the 2 to 2.5 m depth. The first six months of product
recovery involved cones of depression which reduced the average concentration but
extended it over a greater depth (2 to 3.5 m) in some locations. More extensive
dewatering lowered the water table to 3.5 m and extended the contamination over a
greater depth (2 to 4.5 m) prior to the pilot test (t=15). Following 6 months of venting,
the average concentrations decreased in the unsaturated zone above a 3 m depth.
32
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Concentrations remained high, however, in the 3 to 3.5 m depth interval which
constituted a fluctuating water table depth (t=21). Following 6 months of venting and
nutrient supply (t=27), average concentrations had decreased over all depths.
35000
30000
25000
J 20000
w
VI
s
S 15000
10000
5000
(4>t=21
(2>t=
(3)1=15
METRES
Figure 6 Average Trends of Diesel Concentrations in Pilot Trial Area
at Discrete Depths at 6, 15, 21 and 27 month Sampling Periods
During the course of the pilot trial a sequence of visible changes was also
observed in free hydrocarbon collecting in the monitoring wells. Initially increased
darkening (oxidization) was observed in the free product followed by formation of a gel
(emulsification) and a grey slime. Finally only clear water was evident in the wells. A
small amount of free product continues to collect in certain monitoring wells within the
pilot study area, while FP2, outside the study area, shows evidence of oxidization and
emulsification.
Although average concentrations in both Figures 5 and 6 show decreases with
time, the range of concentrations showed little change over the last 12 months of study.
Work is continuing on analysis of the data according to distance from air extraction wells
and oxygen supply.
33
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CONCLUSIONS
Both venting alone and bioventing with the addition of a nutrient supply have
proven a valuable adjunct to free product recovery for attainment of cleanup criteria. The
average rate of hydrocarbon removal was greater with the supply of nutrients and venting
than with venting alone. Much work remains to be done in relating the decrease in
hydrocarbon concentration to localised oxygen and nutrient supply within the pilot area.
Data collected to date suggest that the cleanup criteria of 1500 mg/kg will be met within
the next 12 month period. The data will also provide a good basis for design of the full
scale remediation.
34
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REMEDIATION OF GROUND WATER CONTAMINATED WITH ORGANIC WOOD
PRESERVATIVES USING PHYSICAL AND BIOLOGICAL TREATMENT TECHNOLOGIES
J.G. Mueller; S.E. Lantz; R.L. Thomas:
SBP Technologies, Inc., Gulf Breeze, Fla. 32561, Tel.:1 904 934 9282
D.P. Middaugh; P.H. Pritchard:
U.S. EPA, ERL, Gulf Breeze, Fla. 32561, Tel.:1 904 934 9200
Abstract
Pilot-scale field studies at the American Creosote Works Superfund Site, Pensacola,
Florida, evaluated two technologies for their ability to treat ground water contaminated with
creosote and pentachlorophenol (PCP): 1) Hyperfiltration (volume reduction), and 2)
Bioremediation using specially-selected microorganisms (terminal destruction). The
hyperfiitration unit was operated in a cross-flow mode yielding "concentrate" (containing excluded
chemicals) and "permeate" (clean, aqueous material passing through the membrane.) Operating
over a 6-day period on site, a total of 6,300 gallons of creosote- and PCP-contaminated ground
water (average total semi-volatile concentration was 88.5 mg/L) was processed thereby reducing
the volume of contaminated material >80% while removing >95% of the PAHs. Simultaneously,
the concentration of chlorinated dtoxins and furans were reduced from 22.5 ppb in the feed to
0.047 ppb (cumulative) in the permeate. Based on chemical analyses and biological toxicity and
teratogenicity assays, the permeate stream was acceptable for direct discharge.
A two-stage, continuous-flow, sequential inoculation bioreactor strategy for the
bioremediation of ground water contaminated with creosote and pentachlorophenol (PCP) was
also evaluated. Performance of continually stirred tank reactors using specially-selected
microorganisms was assessed according to chemical analyses of system influent, effluent and
bioreactor residues, a chemical mass balance evaluation, and comparative biological toxicity and
teratogenicity measurements. When specially-selected bacteria capable of utilizing high-
molecular-weight polycyclic aromatic hydrocarbons (HMW PAHs) as primary growth substrates
were used in pilot-scale bioreactors (454 L), the concentration of creosote constituents was
reduced from ca. 1,000 ppm in the ground water feed (flow rate = 114 L/day) to <9 ppm in the
system effluent (removal efficiency of >99%). Notably, the cumulative concentration of 8 HMW
PAHs (containing 4 or more fused rings) was reduced from 368 ppm in the ground water feed to
5.2 ppm in the system effluent. Moreover, the toxicity and teratogenicity of the bioreactor effluent
was significantly reduced. Biodegradation of PCP was limited (ca. 24%) due in large part to poor
inoculation and a high degree of abiotic loss (bioaccumulation and adsorption).
Introduction
Since 1988, SBP Technologies, Inc. (SBP) has been developing the concept of a "multi-
phasic bioremediation strategy" in cooperation with the U.S. EPA Environmental Research
Laboratory at Gulf Breeze, Florida (1-3). This strategy integrates physical and biological treatment
processes for effective and cost-efficient remediation of a variety of substrates (soil, sediment,
aqueous) contaminated by myriad hazardous wastes; organic and inorganic wastes and mixtures
thereof. Depending on the nature of the contaminated substrate (i.e., soil or aqueous material),
the treatment strategy may consist of several discrete phases. For example, treatment of soil or
sediment contaminated with organic and inorganic wood preservatives could entail three phases:
Phase 1, soil washing; Phase 2, dewatering of soil slurry, volume reduction of wash waters, and/or
fractionation of pollutant chemicals by hyperfiitration; and Phase 3, terminal destruction of
concentrated pollutants or recovery/recycling of valuable resources (eg. heavy metals).
35
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In the event that the concentrated pollutants are biodegradable, terminal destruction is
accomplished most effectively via some form of bioremediation. Since the material has already
been concentrated, bioreactor systems are usually more appropriate than other approaches (eg.,
land farming). For pollutants not amenable to biological treatment (eg., heavy metals), then other
technologies, such as incineration, chemical oxidation or solidification, become
more cost effective due to the reduced volume of material requiring treatment.
Other advantages of the multi-phasic strategy using integrated technologies include: 1)
Holistic approach to site remediation: simultaneous treatment of surface water, ground water, soil
and sediment, 2) Ability to treat complex mixtures of organic, inorganic and radioactive wastes, 3)
Pollutants are immediately removed from contaminated matrices and separated into discrete
fractions which greatly facilitates biological degradation, 4) Toxic compounds (i.e., metals,
radionuclides) are removed or recycled prior to biological treatment, 5) Contained systems are
amenable to the future integration of intergeneric microorganisms capable of degrading
recalcitrant compounds, 6) Sole source utilization of high-molecular-weight PAHs by patented
microorganisms facilitates the efficient removal of recalcitrant, carcinogenic and teratogenic
creosote constituents which commonly persist during conventional biological treatment, 7) Ability
to recover/recycle valuable products from hazardous waste sites/industrial effluent: heavy metal
(lead, chromium), petroleum products, 8) Entirely mobile treatment systems foron-site
remediation, and 9) Flexible, versatile systems with broad applicability that can be specially
designed and readily modified for particular needs.
In this paper, we describe pilot-scale field demonstrations of two technologies for the
treatment of ground water contaminated with organic wood preservatives (creosote,
pentachlorophenol) and associated chemicals (chlorinated dioxins/furans): 1) hyperfiltration
(volume reduction), and 2) bioremediation using specially-selected microorganisms (terminal
destruction). These studies were performed at the American Creosote Works Superfund site
(ACW), Pensacola, Florida, in cooperation with the U.S. EPA Superfund Innovative Technology
Evaluation (SITE) Program. The other component of the multi-phasic treatment strategy, namely
soil washing, was not demonstrated since this is basically a "proven" technology, with experience
and expertise being provided by Dredging International, Belgium, and their subsidiaries.
Hyperfiltration System
Technology description: The hyperfiltration system consists of porous, sintered,
stainless steel tubes coated with multi-layered inorganic and polymeric "formed-in-place"
membranes. Membranes are coated at microscopic thickness on the inside diameter of the
stainless steel tubing by the recirculation of an aqueous slurry of membrane formation chemicals
exclusive to SBP. Membranes are specially designed and formulated on a site-specific basis
according to the characteristics of the chemical pollutants and the contaminated substrate. As
shown in Figure 1, the hyperfiltration unit operates in a cross-flow mode yielding "concentrate"
(containing excluded chemicals) and "permeate" (clean, aqueous material passing through the
membrane.) The device can perform filtration ranging from microfiltration to hyperfiltration. In-
house and independent analyses have demonstrated the ability of SBP membrane systems to
extract (retain) heavy metals, caustics and various organic pollutants including petroleum
products, PCP, chlorinated dioxins/furans and creosote (4). Most recent efforts are geared
toward the design and construction of hyperfiltration systems for the recovery of heavy metals
(eg., arsenic, mercury), PCBs, and chlorinated solvents such as TCE.
Pilot-scale field demonstration; Ground water was removed from the shallow aquifer at the
ACW site and transferred to an equilibration tank where oil-phases were passively separated
(upper and lower oil phases and aqueous phase). The resultant aqueous phase was used as the
feed water containing an average total semi-volatile concentration of 88.5 ppm with
phenanthrene (17.1 ppm) and naphthalene (12.9 ppm) as the major contaminants plus 22.5 ppb
cumulative chlorinated dioxins/furans. Operating over a 6-day period on site, a total of 23,850 L of
creosote- and PCP-contaminated ground water was processed (ca. 4000 L7day) with the
objectives of 80% volume reduction and >90% removal efficiency of monitored contaminants.
Process operating data collected included flow rates, temperatures, pressures and electrical and
potable water usage. The feed water, permeate, concentrate and wash water were analyzed for
volatile organic compounds, semi-volatiles, chlorinated dioxins/furans, total dissolved and
36
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suspended solids, oil and grease, total organic carbon and chemical oxygen
demand.
Figure 1: Cross section illustrates stream flow within tubing.
Stainless Steel Tubular Housing
Porous Stainless Steel Tubing
oncentrate
ermeate
Biodegradation System
Technology description: In conjunction with the U.S. EPA Environmental Research
Laboratory at Gulf Breeze, Florida (GBERL), SBP isolated and characterized the first axenic
bacterial cultures capable of utilizing high-molecular-weight PAHs as sole sources of carbon and
energy for growth (U.S. Patent No. 5,132,224). The action of these and other organisms toward
43 priority creosote constituents has been reported previously (5-8). These findings represent a
major advancement in bioremediation technology since the targeted pollutants (i.e.,
fluoranthene, pyrene, benzo[a]pyrene) typically persist during conventional biotreatment
operations (eg.,land farming). Unfortunately, this same group of compounds represents the most
serious threat to human and environmental health. Thus, with the use of these proprietary
microorganisms, the efficiency and applicability of bioremediation technologies has been greatly
expanded to include creosote, coal tar and related wastes.
Pilot-scale field demonstration: A two-stage, sequential inoculation, bioremediation
process was field-tested with ground water, highly contaminated by creosote and PCP, recovered
from the ACW Superfund Site. The first stage of the pilot-scale system used a 454 L completely
stirred tank reactor (EIMCO, Denver, CO) designated FBR1 (field bioreactor 1). The second stage
of the process made use of three, 227 L stirred tank batch reactors (bioreactors FBR2a, 2b and
2c). The bioreactor was operated at a flow rate of 114 L/day with raw ground water containing ca.
1000 ppm semi-volatile creosote constituents and ca. 15 ppm PCP. Additional information on
bioreactor design and operation, including inoculation, sampling and analyses, can be found
elsewhere (7). Efficiency and performance of the bioremediation system using bioreactors and
specially-selected microorganisms was assessed according to chemical analyses of system
influent, effluent and bioreactor residues, a chemical mass balance evaluation, and comparative
biological toxicity and teratogenicity measurements. Liquid/liquid extraction of PCP and creosote
constituents from bioreactor feeds, aqueous effluents, settled biomass and reactor residues was
performed as previously described (3,8); creosote and PCP were extracted from activated carbon
samples as described previously (3,8). Toxicrty and teratogenicity analyses using embryonic fish,
Menidia beryllina, Microtox™ assays, Mysidopsis bahia and Ceriodaphnia dubia tests were
performed as previously described (4,7,8).
Results and Discussion
Hyperfittration system: Over the entire course of the 6-day period, the goal of reducing
the volume of contaminated material >80% was consistently achieved. For every 1000 gallons of
feed water processed, 200 gallons of concentrate were generated and 800 gallons of permeate
was produced. Chemical analyses showed that >95% of the PAHs were removed, and the
concentration of chlorinated dioxins and furans were reduced from 22.5 ppb in the feed to 0.047
37
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ppb (cumulative) in the permeate. The system was less effective in removing the lower-molecular-
weight contaminants, specifically phenol (30% removal efficiency). However, physical analyses
and biological toxicity and teratogenicity assays showed that the permeate stream was acceptable
for direct discharge to the public water treatment plant.
Biodegradation system: Mass balance chemical analyses showed that ca. 64, 77, and
70% of the Group 1 (2 ring PAHs), Group 2 (3-ring PAHs) and Group 3 PAHs (4 or more fused
rings) were biodegraded, respectively (Table 1). Relatively poor performance toward PCP (24%
bfodegraded) was attributed to the use of inocuia of insufficient quality (incomplete induction and
tow cell viability) which was not discovered until after the time of application. During continuous-
flow operations, an average 113 L of ground water feed containing approximately 31, 539,368,
106, <1 and 25 mg/L Group 1 PAHs, Group 2 PAHs, Group 3 PAHs, heterocycles, phenolics, and
PCP, respectively, was added to FBR1 on a daily basis. Based on these removal efficiencies, the
system effluent contained, on average, 0.1,1.6,5.2,1.8 and 5.6 mg/L Group 1,2 and 3 PAHs,
heterocycles, and PCP, respectively. A secondary treatment process using the same
hyperfittration unit to separate of residual contaminants has been developed in the event that
reactor effluent of this quality requires subsequent treatment prior to discharge.
Table 1. Mass balance evaluation3 of pilot-scale studies on the biodegradation of 30 monitored
creosote constituents and PCP by specially-selected microbial strains.
Chemical
Group
Group 1
PAHs
Group 2
PAHs
Group 3
PAHs
Hetero-
cyclics
PCP
Total
System
Input
28256.2
484936.8
331599.9
95506.3
12061.9
System
Discharge
(Output)
47.2
1298.8
5548.0
1603.0
2674.0
Removal0
99.8
99.7
98.3
98.3
77.8
Residue
Settled
Bio mass
fry*
186.0
1320.0
5160.0
1090.0
2376.1
n
Bioreactor
and lines
10020.6
107811.1
88115.3
28437.7
Amount
Volatilized0
44.3
32.9
1.5
47.4
4101.8 <1.0
Amount
Biodegraded (%)d
17958.1
374474.0
232775.1
64328.2
9151.8
(63.6)
(77.2)
(70.2)
(67.4)
(24.1)
Cumulative values following 14 days of field operation (8 days continuous-flow operation);
b% removal - (total system input - system discharge)/total system input x 100;
Calculated value based on intermittent measurements; d% biodegradation =
100 x total system input - (system discharge + biomass residue + line residue + volatilization!
total system input
Whereas analytical chemistry data indicate toss of parent compounds, it is often wrongly
assumed that this loss correlates with a removal of the hazards associated with the original wastes.
This is especially true in the case of bforemediation where slight modification of contaminants can
result in their apparent "degradation". Therefore, in these studies, a series of toxicity and
teratogenicity assays were performed on all starting materials, bioreactor effluent and membrane
permeate. For both the hyperfittration and bioreactor technologies, toss of parent compound
correlated with a significant reduction in the toxicity/teratogenicity of treated material, potential
hazard associated with the treated wastes along with a decrease in the concentration of parent
compound. Based on Microtox™ assays, the reduction in toxicity of ground water by specially-
selected microorganisms was approximately 230- and 130-fold for FBR1 and FBR2, respectively;
tests with mysids indicated a 34- to 75-fold reduction in toxicity for FBR1 and FBR2, respectively,
when compared to ground water. In tests with daphnids, a 75- to 100-fold reduction in toxicity was
noted. Exposure of Menidia embryos to a 1% concentration of ground water resulted in rapid
embryotoxicity (100%). In contrast, the FBR1 effluent was teratogenic (an indication of reduced
38
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toxicity), and 86% of the embryos exposed to effluent from FBR2 developed normally and
hatched without discernible terata; these larva were essentially identical to controls.
Conclusions
The effectiveness of two key components of SBP's multi-phasic remediation strategy was
rigorously evaluated under field operating conditions and ultimately proven at the pilot-scale:
volume reduction via hyperfiltration, and biodegradation of persistent organic contaminants in
bioreactors using specially-selected microorganisms. The integrated use of physical and
biological treatment technologies expands the applicability of bioremediation technologies, and
provides a cost-effective, viable remedial approach for creosote- and similarly-contaminated sites.
Acknowledgments
Technical assistance was provided by Myke'He Hertsgaard, Barbara Artelt, Beat Blattmann,
Maureen Downey, Sol Resnick (Technical Resources, Inc), Cherie Heard, Ellis Kline, Edward
Kouba and Arjan Van Buul (SBP Technologies, Inc). Assistance from Richard Colvin, Derek Ross
(The ERM Group, Exton, PA), Scott Beckman, K.C. Mahesh (SAIC), Kim Kreiton (U.S. EPA,
RREL, SITE Program), and Madolyn Streng (U.S. EPA, Region IV) is also gratefully
acknowledged. Financial support for these studies was provided by the U.S. EPA SITE Program,
Cincinnati, OH. This work was performed as part of a Cooperative Research and Development
Agreement between the Gulf Breeze Environmental Research Laboratory and SBP
Technologies, Inc. (Stone Mountain, GA) as defined under the Federal Technology Transfer Act,
1986 (contract no. FTTA-003).
References
[1]. Mueller, J.G., P.J. Chapman, R. Thomas, E.L. Kline, S.E. Lantz, S.E., Pritchard, P.H.:
Development of a sequential treatment system for creosote-contaminated soil and water: bench
studies. Proceedings U.S. Environmental Protection Agency's Symposium on Bioremediation of
Hazardous Wastes: U.S. EPA's Biosystems Technology Development Program. EPA/600/9-
90/041, p. 42-45 (1990).
[2]. Mueller, J.G., Lantz, S.E., Blattmann, B.O., Chapman, P.J.: Alternative biological treatment
processes for remediation of creosote-contaminated materials: bench-scale treatability studies.
EPA/600/9-90/049. 89 p. (1990).
[3]. Mueller, J.G., Lantz, S.E., Blattmann, B.O., Chapman. P.J.: Bench-scale evaluation of
alternative biological treatment processes for the remediation of pentachlorpphenol- and
creosote-contaminated materials: slurry-phase bioremediation. Environ. Sci. Technol. 25:1055-
1061 (1991).
[4]. Middaugh, D.P., Mueller, J.G., Thomas, R.L., Lantz, S.E., Hemmer, M.J., Brooks, G.T.,
Chapman, P.J.: Detoxification of creosote- and PCP-contaminated groundwater by physical
extraction: chemical and biological assessment. Arch. Environ. Contam. Toxicol. 21:233-244
(1991).
[5]. Mueller, J.G., Chapman, P.J., Blattmann, B.O., Pritchard, P.H.: Isolation and characterization
of a fluoranthene-utilizing strain of Pseudomonas paucimobilis, Appl. Environ. Microbiol.
56:1079-1086 (1990).
[6]. Mueller, J.G., Chapman, P.J., Pritchard, P.H.: Action of a fluoranthene-utilizing bacterial
community on polycyclic aromatic hydrocarbon components of creosote. Appl.
Environ. Microbiol. 55:3085-3090 (1989).
[7]. Mueller, J.G., Lantz, S.E., Middaugh, D.P., Colvin, R.J., Ross, D., Prftchard, P.H.: Strategy
using bioreactors and specially-selected microorganisms for bioremediation of ground water
contaminated with creosote and pentachlorophenol. Environ. Sci. Technol. (submitted).
[8]. Mueller, J.G., Middaugh, D.P., Lantz, S.E., Chapman, P.J.: Biodegradation of creosote and
pentachlorophenol in groundwater: chemical and biological assessment. Appl. Environ. Microbiol.
57:1277-1285 (1991).
39
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THE DESIGN CRITERIA AND ECONOMICS OP OPERATING
A PULL-SCALE ABOVE-GROUND BIOREMEDIATION FACILITY
FOR THE TREATMENT OF HYDROCARBON CONTAMINATED SOILS
by
Robert Mall
Environmental Specialist
KJC Operating Company
40
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SUMMARY
The bioremediation of soil contaminated with certain hydrocarbons,
has been demonstrated as an effective and economical alternative
waste treatment technology. This paper focuses on a project which
was specifically designed and implemented to treat soils
contaminated with a synthetic heat transfer fluid.
INTRODUCTION
Due to increasing hazardous waste disposal costs, rapid regulatory
changes, and a corporate policy of sound environmental practices,
the operators of the world's largest solar electric generating
systems (SEGS) embarked on a program to eliminate the need for off-
site disposal of hydrocarbon contaminated soils.
The SEGS technology employ line-focus parabolic trough mirror
collectors to focus and concentrate sunlight onto heat collection
elements (HCE). The HCE's are filled with a unique heat transfer
fluid (HTF) which is circulated through the solar fields and heated
to between 600 and 750 degrees Fahrenheit. The HTF is pumped
through a series of heat exchangers, generating steam which in turn
passes through a turbine generating electricity. HTF is an
eutectic mixture of 26.5% Biphenyl and 73.5% Diphenyl Oxide.
Accidental releases of HTF from the SEGS systems sometimes result
in contamination of soil. Historically, this meant excavation,
transport, and disposal in a class I hazardous waste landfill. In
an effort to reduce the cost of disposal, conserve limited landfill
space, and implement a soils recycling program, bioremediation was
studied as an on-site alternative treatment technology.
TREATMENT PROCESS DESCRIPTION
The treatment technology employs solid phase bioremediation which
is environmentally controlled to optimize degradation processes.
By utilizing naturally occurring microorganisms, HTF soil
contaminants are metabolized into harmless by-products. Treatment
is conducted within a fixed containment facility.
MEDIA AND POLLUTANTS TREATED
The waste stream consists of well-defined coarse and medium grained
sands and a small percent of clayey silts and gravel contaminated
with HTF (biphenyl and diphenyl oxide).
PROJECT DEVELOPMENT STATUS
Two pilot scale projects, conducted over an 18-month period, were
successful in reducing HTF concentrations to below the target
"clean-up" level of 1000 ppm. The positive results achieved
prompted the implementation of a full-scale project. A full-scale
treatment demonstration project has been underway for the last 24
months.
41
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INITIAL AND FINAL POLLUTANT CONCENTRATION
Initial contaminant concentrations vary with the quantity of HTF
released and surface area of contamination. Concentrations
typically average about 7,500 parts per million (ppm); with an
observed range from less than 2,000 ppm to as high as 20,000 ppm.
Treatment requires approximately 90 days to accomplish contaminant
removal to below 1000 ppm. Treatment to levels less than 100 ppm
are possible, however this lower treatment level is contingent upon
initial concentrations, favorable environmental conditions and is
generally time dependent.
PROCESS LIMITATIONS
Treatability studies have shown that the most critical limiting
factors are:
1. Soil pH
2. Moisture
3. Temperature
4. Nutrients
5. Oxygen supply
(6 to 8)
(40 to 60 % of saturation)
(65 to 85 degrees F)
(Variable)
(Variable)
The ability of the operator to manage these conditions will
determine whether an ideal environment can be created to stimulate
bacterial population growth and enhance the degradation process.
To enhance aerobic bacterial growth and reduce the potential odor
problems associated with anaerobic conditions, the soils are tilled
on a^ 72-hours schedule. A good oxygen supply, in concert with a
sufficient moisture contentr stimulates bacterial growth and
promotes mobility,
PROCESS WASTE STREAMS
If properly managed, the process produces no residual hazardous
waste or other conditions of concern. Treatment is viewed as a
form of "geo-reclamation"; the recycled material is to be used as
"clean" backfill on site.
AGENCY INVOLVEMENT
As with any project of this nature, it is necessary to consult with
a variety of regulatory agencies. It is important to gain a full
understanding of the regulatory conditions before spending too much
time and money on development. In order to avoid duplication of
agency requirements, a workshop should be set up to bring all
concerned parties together to discuss the project in full. In the
case of this facility, a meeting was held to discuss and establish
the treatment process and goals. The proposed facility design and
construction parameters were compared to regulatory statutes for
adequacy and compliance.
42
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Sampling protocol and monitoring requirements, as well as
regulatory concerns and comments, were addressed. The "lead"
agency was established and the necessary approvals obtained.
The California State agencies involved in the project are:
CAL\EPA - Region 4 (Facility Permitting Unit) (CAL\EPA)
CAL\EPA - Alternative Technology Division (ATD)
Regional Water Quality Control Board (RWQCB)
Air Pollution Control District (APCD)
County Environmental Health Services (EHS)
California Energy Commission (CEC)*
* Conditions of Certification issued by the CEC required
their involvement in this project. The CEC would not
normally be involved in waste treatment projects.
DESIGN AND CONSTRUCTION CRITERIA
There are several factors which must be considered when determining
a facility's design. While economic considerations may dictate the
options selected, regulatory requirements will ultimately direct or
limit those options.
The primary consideration should be environmental protection. This
usually means containment features to ensure prevention of
groundwater and vadose zone degradation, but may also include
contaminant emissions to the atmosphere.
Regulatory requirements will dictate minimum protection standards
and tolerances. The selection of materials used for containment
should also consider durability, exposure to environmental
elements, load factors, and the contaminant being contained and
treated.
High-density polyethylene (HOPE) or similar materials are widely
used for this type of application, and are easily installed and
relatively inexpensive. Natural clay barriers can also satisfy
containment requirements, however, they can be very expensive to
install because of intensive labor requirements and import costs.
To prevent run-on and/or run-off from precipitation, the facility's
containment area properly configured and the perimeter
appropriately graded. In some cases, the entire facility can be
covered or, at additional cost, a roof constructed over the
treatment area. This may be necessary in areas where average
ambient temperatures are below 65 degrees Fahrenheit for prolonged
periods of time, or regions where high precipitation occurs. Cost
figures for roofing applications are not considered in this paper.
Because water is applied to the facility, leachate collection and
recovery systems (LCRS) must be installed directly below the
treatment zone. The LCRS acts as a first line of defense against
a possible release from the facility.
43
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The LCRS allows collected fluids to be returned to the treatment
zone and warns of a possible facility breach. Should fluids enter
the LCRS, inspection and repair of the facility should occur
immediately following confirmation that the fluid is leachate.
Installation of vadose zone and groundwater monitoring devices are
often required to detect possible releases beyond the LCRS and into
the unsaturated zone or water table below the facility.
Once appropriate containment and monitoring systems have been
determined, facility sizing should be calculated. Facility
dimensions should be sufficient to handle only the anticipated rate
and volume of waste material generated. A minimal storage
structure should be appropriately sized and considered as a
contingency, should unusual events require temporary storage of
material prior to treatment.
It may be of value to partition the treatment zone into two or
three individual treatment areas to allow a staggering of start and
end dates of smaller batch treatment processes.
FULL-SCALE FACILITY AS DESIGNED
This full-scale facility's design incorporates primary and
secondary containment features, a triple LCRS installation,
equipment access requirements and environmental control devices.
The facility is 225' long, 60' wide and 2.51 deep with an annual
throughput capacity of approximately 1,500 cubic yards or roughly
2,000 tons.
The facility was constructed with 7 inches of reinforced concrete
as the primary containment structure. The concrete was coated with
a chemically resistant sealant. An elaborate triple-liner system
of HOPE was installed below the concrete. This required secondary
containment is made up of two 40 mil and one 80 mil HOPE liners.
There is a "geo-fabric" material between the two 40 mil liners
which acts as a wick to assist in the recovery of fluids which may
collect between these two liners. A LCRS exists between the
concrete and the upper 40 mil liner; between the two 40 mil liners;
and between the lower 40 and bottom 80 mil liners.
The area between the 40 and 80 mil liners was backfilled and
compacted with 2' of native soil, and designated the lower vadose
(unsaturated) zone; the third LCRS acts as the primary vadose zone
monitoring system, therefore no additional subsurface monitoring
devices (i.e. lysimeters, neutron probe casings, etc.) were
installed below the 80 mil liner.
A broadcast watering system was installed and set up on a timing
device to maintain proper soil moisture content. Soil moisture
readings are taken every three days.
44
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MONITORING REQUIREMENTS
Because of the relatively small size of this facility, it was not
practical to install groundwater monitoring wells for purposes of
detecting a leak from the facility. The depth to groundwater is
greater than 150 feet, and contaminant pathways are not well
defined. As a result, it would be virtually impossible to
construct a well monitoring system that could adequately detect any
degradation of the groundwater due to a leak from this facility.
Hence the triple liner and LCRS system. The LCRS are monitored on
a quarterly basis.
ECONOMICS
An economic comparison of various alternatives to the operation of
a bioremediation facility show that it is cost-effective to
construct and operate a bio-facility. This assumes, however, that
either a substantial volume of waste exists, or is expected to be
generated over the operating life of the project.
INITIAL CAPITAL COST
Pilot-scale testing conducted at this site cost about $15,000.00
over 18 months. The full-scale facility has thus far required
agency fees totalling $85,000.00, including financial assurance for
eventual facility closure.
Full-scale facility construction requirements and associated costs
made up the bulk of first year capital expenses. Facility design,
plan check fees, material and labor, as well as administrative
oversight, has resulted in a capital expenditure of approximatelv
$220,000.00. *
Total project costs amounted to about $320,000.00. Actual costs
may be higher if the purchase of earth moving and tilling equipment
is required.
TREATMENT COSTS
Annual treatment costs for bioremediation are relatively low by
comparison to other methods of treatment. Costs are directly
related to manpower and equipment needs, as well as materials
consumed (i.e. nutrients, water, etc.). Sampling and analytical
costs will vary depending upon the frequency of sampling and the
type and quantity of tests performed on each sample.
Overall operating costs will also be contingent upon the size of
the facility and number of treatment batches completed. For this
facility (which processes three 500 cubic yard batches per year),
the total annual cost of operation runs approximately $35,000.00.
This figure includes all of those factors indicated above.
45
-------
ECONOMICS OF OPERATIONS
In deciding whether on-site bioremediation is practical, the focus
is primarily on economic payback. By comparison to some of the
alternatives, such as landfilling, incineration, solidification,
thermal desorption, and vapor extraction, bioremediation can be
very attractive.
The key questions as to whether or not on-site bioremediation is
attractive or not are:
How much waste do I currently have to treat?
How much am I generating over what period of time?
Are there regulatory limitations in dealing with this waste stream?
Do I have land availability to conduct on-site treatment?
Am I under some time constraint to solve the problem?
Do I have the means in-house to attend to on-site treatment?
Is the waste stream hazardous or not? And finally,
What are my long term goals?
If the answers to the above questions are favorable towards
implementing an on-site bioremediation facility, the operating
costs are minimal and payback can be relatively rapid. The factors
that play a role in facility operating costs are: frequency of soil
aeration (labor), purchase of supplemental nutrients, water,
sampling and analytical expenses, and administrative oversight.
For this particular facility, and a total first-year investment of
$220,000.00 (construction), and $35,000.00 (operations), on-site
bioremediation produced a per treated cubic yard cost of about
$170.00, or $30.00 per yard less than the cost for landfilling the
waste. In the second year, given the same volume treated, the
cost drops to about $26.00 per yard without amortization of
facility construction. An additional cost reduction, to about
$21.00 per cubic yard, was realized once sampling and analytical
parameters were reduced to minimum requirements. Experience gained
over time will allow the operator to reduce sampling to the minimal
requirements.
A comparison of the first year costs of selected alternatives, are
generally competitive. In the second and subsequent years of
operation, the cost of conducting on-site bioremediation is
dramatically less on a per volume basis. For example: Treating
1,500 cubic yards of contaminated soil would result in the
following first-year expenditure, using the treatment or disposal
method shown in the following chart. In the second year, there is
a significant difference in the cost of bioremediation compared to
the other methods.
46
-------
METHOD
Incineration
Solidification
Landfill
Thermal Desorption
Bioremediation
1st year
$787,500.00
$165,000.00
$322,500.00
$300,000.00
$255,000.00
2nd year
NO CHANGE
it
ii
n
$39,000.00
3rd year
NO CHANGE
n
n
$31,500.00
These comparison figures are averages of actual quotations and
information obtained from articles printed in various industry
publications for the method indicated. The bioremediation figures
are actual costs based on this project.
It should be remembered that the economic variables affecting
individual on-site bioremediation projects will be influenced by
regulatory requirements, the cost of construction materials and
facility scale, the type and concentration of the contaminant being
treated, the climatic conditions of the area, and the amount of
waste to be treated annually. Therefore, each of these factors
must be considered individually and specifically for each project.
CONCLUSION
This project and the effectiveness of bioremediation has proven
itself, both environmentally and economically. In a world of
tighter and tighter regulatory requirements, rising cost of
hazardous waste treatment and disposal, and public awareness of
environmental problems, there is no doubt that on-site
bioremediation is a sound, cost-effective solution to a variety of
hydrocarbon contaminated soil problems.
47
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Biopur*
An Innovative Bioreactor for the Simultaneous Treatment
of Groundwater and foil Vapour Contaminated with Xenobiotic Compounds
TAUU Infra Consult B.V.. P.O. Box 479, 7400 AL Oeventer, The Netherlands,
Introduction
At many places the soil, groundwater and soil vapour are contaminated with organic
compounds. A bioreactor was developed to treat groundwater and soil vapour simultaneously.
This system is called Biopur*. Contrary to conventional physico/chemical methods,
biological treatment does not cause waste problems and is therefore an attractive method.
The Biopur* system is patented.
Background
Biological groundwater treatment in fixed film reactors, has been used by TAUW Infra
Consult B.V. since 1986. Trickling filters were used initially, followed by Rotating
Biological Contactors (RBC). Groundwater heavily contaminated with benzene, mono-chloro-
benzene and HCH could be treated. Removal efficiencies of up to 98X were obtained.
Furthermore, at in situ remediation sites, there was a need to develop a system to treat
soil vapour in combination with groundwater. For these reasons the Biopur* was developed.
The Biopur* is a fixed film bioreactor with polyurethane as a carrier material for the
bioroass. The flow of air and water is co-current to prevent the volatile compounds being
stripped (see Figure 1).
Cenpartaent filled with
Polyurethane iponeei therein
air and water * '•'
are being treated
Treated grounduater
Figure 1; An Overview of an In Situ Application of the Biopur* Reactor for the
Simultaneous Treatment of Soil Vapour and Groundwater
48
-------
Results - Pilot Plant Scale
The Biopur* was tested for groundwater treatment at pilot plant scale, the results of one
experiment are given in Table 1.
Table 1; Results of Pilot Plant Research
Site
Former Gasworks
Configuration 1
BTEX
PAH (16 EPA)
Mineral Oil
Configuration 2
BTEX
PAH (16 EPA)
Mineral Oil
HRT Influent
(hours)
-------
Table 2: Results of Full Scale Experiments
Site
Raalte I
BTEX
Mineral Oil
Overslag
BTEX
Mineral Oil
Utrecht
BTEX
Mineral Oil
Raalte II
BTEX
Mineral Oil
HRT Influent
(hours) «i9/O
0.25
650
< 100
1
39
350
0.25
1300
323
1.2
261
1050
Effluent
Otg/l)
< 0.5.
< 100
< 1
55
3
36
< 1
50
Removal
Efficiency X
> 99.9
not applicable
> 97.4
84.2
99.7
88.8
< 99.6
95.2
Results • Simultaneous Treatment of Groundwater and Soil Vapour
The Biopur* was used at a site to simultaneously treat contaminated grounduater and soil
vapour. A mass balance of the system is shown belou.
soil
vapour •-"•
(50 m3/h)
210 g/h
Biopur*
•> < 3 g/h exhaust fumes
groundwater — 10 g/h
(15 ra3/h)
-»• < 2 g/h effluent
The mass balance shows that 5 kg of petrol was removed daily with hydraulic retention
times of less than 15 minutes.
The exhaust fumes did not contain detectable organic compounds (<0.1 ppm) and could be
disposed of without being treated. The treated groundwater from the site was discharged
into surface water.
Treatment Costs
Related to the entire remedial action the treatment costs of soil vapour and groundwater
were less than DM 0.40 per m of groundwater. For calculation purposes only, the treatment
of the soil vapour was free of charge.
In Table 3 a comparison of the treatment costs of four types of groundwater purifying
plants is given.
50
-------
Table 3: Comparison of the Treatment Costs of Four Types of Groundwater Purifying Plants
Type
Costs (DM) per m of grounduater
10 m /hour 20 m /hour 40 m3/hour
1
2
3
4
Biopur*
Rotating biological contactor
Stripper/activated carbon
Stripper/compost filter
0.53
0.78
0.85
1.16
0.44
0.65
0.54
0.87
0.35
0.59
0.36
0.72
Conclusions
(1) Groundwater contaminated with organic compounds, such as BTEX, PAH, mineral oil end
chlorinated hydrocarbons can be treated by using the Biopur* process.
(2) The Biopur* can be used for simultaneously treating biological groundwater and soil
vapour.
(3) Using the Biopur* process good removal results were obtained with relatively short
hydraulic retention times.
(4) Application of the Biopur* process in groundwater/soiI vapour treatment is cost
effective.
We are prepared to discuss specific problems and to find a way of cooperating in complex
environmental fields.
Should you require further information please contact:-
B.A. Butt (H.Sc.)
Head, Water Technology Sector
Telephone number +31-5700-99862
H.B.R.J. van Vree (H.Sc.)
Project Leader, Research & Development
Telephone number +31-5700-99561
51
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to
Optimizing Bioventing in Shallow Vadose
Zones and Cold Climates: Eielson
AFB Bioremediation of a JP-4 Spill
Gregory D. Sayles, Ph.D.1
and
Robert E. Hlnchee2, Richard C. Brenner1, Catherine M. Vogel3 and Ross N. Miller4
'U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH
2Battelle Memorial Laboratory
Columbus, OH
3 U.S. Air Force Civil Engineering Services Agency
Tyndall AFB, FL
4 U.S. Air Force Center for Environmental Excellence
Brooks AFB, TX
-------
Eielson AFB: Background
JP-4 jet fuel contaminated
unsaturated soil
CA
• Contamination from leaks in
underground fuel distribution system
Soil contaminated from 2 to 6 ft
(groundwater at 6 ft)
-------
Eielson AFB: Background (continued)
U.S. EPA, U.S. Air Force, and Battelle
began work here in July 1991
3-year study
Funded by
- U.S. EPA Bioremediation Field Initiative
- U.S. Air Force
-------
Eielson AFB: Project Objectives
Document bioventing in a cold climate
- average annual air temp = 0*C
Evaluate various soil warming methods to
enhance bioventing rates
- active warming with warm water
- passive solar warming
-------
\
o\
N
Schematic of Eielson AFB Three Test Plots
Passive
Site Trailer
Active
Warming
System
Control
Groundwater monitoring well
Air injection/withdrawal well
Three-level soil gas probe
Three-level thermocouple probe
25'
Scaie
50'
-------
Cross-Section of EPA Active Plot Showing General
Site Lithology and Bioventing System Construction Details
Ground Surface
- Plastic Sheeting
I— Styrofoam Insulation
Groundwater
Monitoring
Well (MW-3)
Three-Level
Thermocouples
Air Injection/Withdrawal Well
/ Three-Level
r Soil Gas Probe
B
C(S6)
— Plywood
- Blue Vinyl
Cover
rial B
Valve A
Brown Sand
and Gravel
Heat
Tape
Backfill
fi h > > > > > > >
;. A-Vxy^ V A-
%%%%%%%*& Sand and Gravel x;\
8S\\\N\VN
- i**>W.%W.%V
Gray Sandy Gravel
Sand
Bentonite
10-
-------
Oxygen Concentration in Three Test Plots and Background
August 22, 1991 to July 11, 1992
25-
Initiation of Air Injection
Initiation of- r-Pressure Pulse
Soil Heating
Reduction of Water Circulation
on Soaker Hose
1 1 1 1 1 1 1 1 T
Sept. Oct. Nov. Dec. t, Jan. Feb. Mar. Apr. May June July
1991 1992
Active Warming
Passive Warming
Contaminated Control
Uncontaminated Background
-------
Soil Temperature in Three Test Plots and Background
VO
28
24
20
16
fi
12
0)
Q.
£ 8
-4
Active Warming
Uncontaminated Background
Contaminated Control
Passive Warming
Sept. Oct. Nov. Dec. Jan. Feb. Mar. April May June July Aug.
Time (Days)
-------
Biodegradation Rates at Eielson AFB
8
10
I 8
^
O)
6-
O)
5
DC
I 4
I
2
O)
0)
0
• Active Warming
• Passive Warming
A Contaminated Control
October
January
April
August
-------
Eielson AFB: Conclusions
o\
Active soil warming is successful
Optimization of active heating
and aeration necessary
Passive solar heating looks
very promising
Biodegradation via bioventing is
occurring year-round in all plots
-------
BIO-REM, INC.'S AUGMENTED IN SITU SUBSURFACE
BIOREMEDIATION PROCESS (TM) USING BIO-REM, INC.'S
PROPRIETARY BIOCULTURES (H-10) FOR THE REMEDIATION
OF JP-4 CONTAMINATED SOILS AT WILLIAMS AFB f AZ
In 1987, ten 25,000 gallon JP-4 aviation jet fuel tanks were
removed from the Primary Fuels Storage Area at Williams AFB, AZ.
Extensive contamination was discovered; laboratory analysis
revealed contaminant levels in excess of 88,000 ppm of JP-4, and
the site was closed and subsequently placed on the National
Priority List (Superfund List) for future clean-up. In August of
1991, after the base had been listed for closure by the U.S.
Government, an award .was made for the initial clean-up of the
contaminated site, designated as Operable Unit-2 of this
Superfund site.
In September of 1991, the clean-up contract was awarded to a
construction firm from Stockton, California to excavate and pile-
remediate 16,000 cubic yards of JP-4 contaminated soil. However,
due to State of Arizona and Maricopa County, Arizona Air Quality
standards and regulations concerning volatile organic compound
(VOCs) emissions, this methodology was rejected. The Bio-Remfs
Augmented In Situ Subsurface Bioremediation Process (TM) and Bio-
Rem's H-10 microaerophilic bacterial cultures were selected to
remediate the site.
REMEDIATION METHOD: The initial stages of the bioremediation of
the Fuels Storage Area at Williams AFB, AZ began in April of
1992. Over 320 borings and monitor wells were placed on the
site. Bio-Rem H-10 Product was propagated and subsequently
placed into the contaminant plume, through these borings and
wells, over a period of ten (10) days. Then the site was covered
with plastic sheeting to reduce evaporation.
I. Technical Information.
A. Description of Technology.
Bio-Rem, Inc.'s Process and BiocuJture are commercially
available and have been used in over 75 sites in 14 states. The
Augmented In Situ Subsurface Bioremediation Process (TM)
incorporates four (4) steps in the subsurface bioremediation of
hydrocarbon contamination in soil and water. This process occurs
totally underground. It utilizes Bio-Rem, Inc.'s Product "H-10",
a proprietary blend of microaerophilic bacteria and
micronutrients. After placement, Bio-Rem H-10 does not require
additional injections of nutrients, oxygen, or oxygen-producing
compounds (i.e. hydrogen peroxide). Furthermore, the by-products
of the degradation process are naturally occurring elements;
therefore, this process complies fully with Title I of the Clean
Air Act.
62
-------
10,000
5,000
1,000
500
400
300
200
100
0
BIO-REM, INC.
WILLIAMS AFB, ARIZONA
10/8 10/22
-------
BIOREMEDIATION OF SOILS AT A WASTE OIL FACILITY
Gary Guerra
On-Scene Coordinator, USEPA Region VI
Dallas, TX
John Matthews
Bert Bledsoe
Environmental Scientists
Robert S. Kerr Environmental Research Laboratory
Ada, OK
Daniel F. Pope
Senior Staff Scientist
Dynamac Corporation
Ada, OK
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OK 74820
64
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Bioremediation of Soils at a Waste Oil Facility
The Baldwin Waste Oil site is located approximately 1.5 miles north of Robstown, a small town near Corpus
Christi, Texas. Site weather is typical of Gulf Coast conditions: the summers are hot and humid, and winters are mild
with frost conditions averaging about seven days each year. The site, an abandoned waste oil facility occupying
slightly more than one acre, is surrounded by agricultural lands. The north half of the facility is occupied by two
tank farms surrounded by earthen containment dikes and a caliche drive. The south half is a low area with
vegetation and debris, bordered on three sides by a drainage ditch located just inside the property line. A small pond
filled with sludge and water is located beside one group of tanks. Oil, water, and sludges were located in fifteen
large storage tanks, five 55 gallon drums, numerous small containers and two containment berms surrounding the
two groups of storage tanks. Areas between the tanks are covered with a sludge layer.
During operation, the facility received a large portion of its waste oil from the local navigation district
ballast pits, used to store waste oil collected from slop tanks of ocean-going oil tankers. Waste oil was transported
to the site and pumped into one of several mixing tanks where the oil was blended with solvents (benzene, toluene
or xylene) for resale.
The native soil at the site is the Victoria clay. Characteristics of this clay material include: low permeability,
high water-holding capacity, high compressibility, high to very high shrink-swell potential, poor drainage, low to
depressed relief, low shear strength, and high plasticity. A particle size analysis of the Victoria clay soil indicated
a sand content of 43%, a silt content of 10%, and a clay content of 46%. A caliche fill material, classified as a silty
clay, is also present Particle size analysis of the caliche material indicated a sand content of 53%, a silt content
of 10%, and a clay content of 36%. Analysis of soil samples indicated levels of benzene, ethylbenzene, toluene,
xylene (BTEX) of 50 ppm or less; elevated levels of lead, chromium, barium, arsenic, and total petroleum
hydrocarbons.
The remedial plan for the site provided for removal of tanks, barrels, buried piping, debris and sludges.
However, approximately 1500 to 2200 cubic yards of contaminated soils that had been under an oily sludge layer
on the tank farm area remained to be disposed. This soil contained levels of total petroleum hydrocarbons up to
50,000 ppm. Treatment processes considered for the soil included incineration or in-situ bioremediation based on
the land treatment concept. Bioremediation technology was chosen for pilot testing to determine the feasibility of
the innovative use of this technology in-situ during the removal action. The treatment goals to be achieved during
the removal program are concentrations of less than 1% oil and grease (O&G) and 10,000 mg/kg total petroleum
hydrocarbons (TPH).
Bioremediation based on the land treatment concept involves use of natural biological, chemical and physical
processes in the soil to transform organic contaminants. Biological activity apparently accounts for most of the
transformations of organic contaminants in soil. Bioremediation is carried out by utilizing techniques for enhancing
the development of the microorganisms and bringing them in contact with the contaminants. Conventional land
treatment has been shown in a number of instances to be a viable treatment alternative for soils contaminated with
oils and hydrocarbons. However, there was some concern that compounds or elements might be present at the
Baldwin site which could inhibit microbial activity in a land treatment unit. Laboratory tests conducted by Dr. Alan
Marker of the University of Oklahoma indicated the presence of a population of active petroleum hydrocarbon
degrading microorganisms, so it was decided to conduct a pilot scale land treatment study in the field.
The pilot scale land treatment system was designed to evaluate the feasibility of utilizing in-situ remediation
of the contaminated soils. Objectives of the pilot scale demonstration were to:
1) Demonstrate the efficacy of in-situ bioremediation for the oil contaminated soils at Baldwin Waste
Oil site under field conditions;
2) Collect statistically defensible data on which to base conclusions of bioremediation efficacy;
3) Identify potential problems in implementing a full-scale bioremediation project;
65
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4) Collect data which will be necessary for the full-scale implementation of in-situ bioremediation at
the site.
The pilot system was constructed outside the bermed area so the system could be left in place during
removal operations associated with the site tank waste disposal and demolition. A treatment plot approximately 33
feet long and 12 feet wide was constructed with the bottom sloped (about 2-4% slope) toward the middle of the area
and about a 1-2% slope toward one end. A two foot berm was provided to prevent any run-on or run-off from rain
or irrigation. A high density polyethylene liner was anchored within the bermed area and covered with five inches
of pea gravel and eight inches of sand to allow for drainage and help protect the liner during tilling of the unit. A
slotted PVC pipe was installed down the medial axis of the plot for leachate collection.
The two contaminated soil types (the native clay and caliche fill material) were kept separate in the
treatment plot in order to determine the effect of soil type on treatment management and efficacy. For sampling,
the plot was divided into six cells (6 ft by 10 ft.), with three cells representing each of the two soil types. The north
side of the treatment unit (cells NW, N, ME) contained the caliche material, and the south side of the treatment unit
(cells SW, S, SE) contained the native clay material. An eight inch thick layer of each contaminated soil was placed
on the plot, and two inches of composted chicken manure was tilled into the soil for conditioning and as a source
of nutrients. The manure contained about 11,000 ppm EDTA extractable phosphate phosphorus, 30,000 ppm EDTA
extractable potassium, 2.4 % total kjeldahl nitrogen (TKN), and 14% total organic carbon. Nutrient content of the
amended soil is shown in Table 1. Nitrogen and phosphorus were monitored throughout the study, and fertilizer was
added as needed to maintain the appropriate levels of these nutrients. A movable overhead irrigation system was
used to add water as needed. Leachate from the pilot unit was collected for analysis.
Samples for the starting concentration (Week 0) were collected after the compost had been tilled into the
soil. Samples taken at later sampling times were taken immediately after tilling to aid in sample homogenization.
Five evenly spaced subsamples were taken within each cell. These subsamples were mixed to get one composite
sample for each cell. Volatile organic compounds were measured on grab samples to minimize loss of the volatile
components. The grab samples were taken at three locations in each cell using a soil coring sampler with acetate
sleeves.
Week 0 soil samples were analyzed for nutrients, pH, oil and grease (O&G), total petroleum hydrocarbons
(TPH), volatile organics (VOC), semi-volatile organics (S VO), polynuclear aromatic hydrocarbons (PAHs) and total
organic carbon (TOC) (See Tables 1 - 3 and Figure 1). O&G, TPH, pH, and nutrients also were measured at Weeks
3, 6, 10, 21, 28, 36.40 and 43 as operational parameters to determine the course of treatment. Once the operational
parameters reached a steady state at Week 43, the full suite of analyses was performed to determine the treatment
cndpoints.
The project was started in November of 1991 since November is normally the beginning of the annual dry
season for the Robstown area. However, the rainfall for the next ten weeks was far above normal (Figure 3). The
project was proposed to end by the 12th week, but the unusually high and continued rainfall precluded tilling and
other operations at the site during this period, so the project was extended. Significant degradation of O&G and TPH
occurred during this period even though the LTU was saturated at times. Analyses of leachate from the pilot unit
indicated TPH and O&G levels were below detection limits. Treatment levels at the 43rd week were considered
acceptable since TPH and O&G concentrations approached or were below the removal program cleanup goals.
Volatile organics and semivolatile organics, present at low parts per billion levels at the beginning of the study, were
at nondetect levels by the end of the study. Based on reduction of TPH and O&G to cleanup goals and reduction
of volatile and semivolatile organics to nondetect levels, in-situ bioremediation based on the land treatment concept
has been selected as the remediation alternative for full scale clean up under the removal program.
The pilot scale demonstration study was conducted through the cooperative effort of USEPA Region VI
Superfund Program and their Technical Assistance Team contractor (Ecology and Environment, Inc.), and the
USEPA Robert S. Kerr Environmental Research Laboratory Subsurface Fate and Transport Technology Support
Center and their technical support contractors (Dynamac Corporation).
66
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Tabk 1. Status Of LTU Soil At Week 0
Electrical Phosphate
Sample Location .. Conductivity Total Total Kjeldahl Phosphorus
(Cell) mmhos/cm Organic Carbon % Nitrogen % ppm
SW 4.5
S 5.4
SE 5.2
NW 5.4
N 5.1
NE 5.2
1.1
2.4
1.1
1.0
1.3
1.2
0.06
0.20
0.05
0.16
0.13
0.13
42.8
76.1
68.5
42.4
38.0
40.3
Potassium
ppm
1250
1176
1283
1144
1048
1175
Table 2. Total Petroleum Hydrocarbons In LTU Soil
Sample
Location Type
. to
NW
NW D
NW R
NE
N Mean
S
SW
SW D
SW R
SE
SMean
Week 0 Week 3
31900
38100
48700
39567
14400
14300
14500
14400
Table 3. Oil And Grease In
Sample
Location Type
N
NW
NW D
NW R
NE
N Mean
S
SW
SW D
SW R
SE
5 Mean
22300
21200
25400
22967
7800
25200
19800
17600
LTU Soil
WeekO Week 3
5.8
8.6
8.4
7.6
2.1
3.8
2.4
2.7
2.5
2.6
4.1
3.0
0.9
2.9
2.3
2.0
Total Petroleum Hydrocarbons (mg/kg)
Week 6 Week 10 Week 21 Week 28 Week 36
16100
17900
19500
17833
5800
7300
9100
7400
Week 6
3.5
25
2.7
2.9
1.6
1.4
1.5
7.5
16000
13400
15600
15000
4200
4700
95OO
6133
Oil and
Week 10
5.2
2.4
3.0
5.5
0.9
2.6
1.9
1.8
40590
12770
25750
26370
6876
4292
11390
7519
Grease (%
Week 21
5.1
2.0
3.5
3.5
1.5
1.0
1.9
1.4
17570
16345
16090
16668
6675
9728
7075
7826
Dry Weight)
Week 28
2.1
1.9
2.0
2.0
0.8
1.2
1.3
1.1
10590
9479
13120
11063
4248
4845
6450
5181
Week 36
1.9
1.9
2.2
2.0
1.4
1.2
1.5
1.3
Week 40
8929
7415
6759
7007
10240
8070
5024
4586
5761
4713
9454
5908
Week 40
1.2
1.0
0.8
0.9
1.4
1.0
0.5
0.6
0.7
0.5
1.3
0.7
Week 43
6854
8015
6917
8426
9264
7895
3771
2233
2707
4375
5361
3689
Week 43
1.2
1.3
1.2
1.6
1.6
1.4
0.7
0.6
0.7
0.9
1.0
0.8
67
-------
TOTAL PETROLEUM HYDROCARBONS IN LTU SGML
NORTH CELLS
soooo
44000
4OOOO <
UJ MOOO'
I30000
f 2 5000
20000
E 18000
10000
(000
0
W**k21
WMk43
TOTAL PETROLEUM HYDROCARBONS IN LTU SOIL
SOUTH CELLS
80000 *
49000
40000<
u ttOOOi
i 30000'
« 25000
^20000
fe 1SOOO
10000
5000
0
WM*O
WMk21
Jomptng CXrt*
WMk2«
WMkW
W««k40
WMk43
Figure 1. TPH in LTU Soil.
68
-------
10 • <
• ' >
»< >
S 7..
OH. 4 GREASE WLTU SOU-
NCR TH CELLS
Sonping Dot*
OB. & GREASE IN LTU SOU.
SOUTH CELLS
•i. 7< '
E ••
5 s
a «•
=!
o
WMk3
WMK 10 WMK n
Samplng Da)*
Figure 2. % O&G in LTU Soil.
MONTHLY PRECIPITATION
Figure 3. Rainfall During the Pilot Study.
69
-------
WeekO
Week 6
Week 43
Figure 4. Gas Chromatography Chromatogram of a Hexane Extract of Treated Soil.
70
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Low Temperature Thermal Treatment LT3 Site Demonstration
By Michael G. Cosmos, P.E.
Roy F. Weston, Inc.
The LT3. was used as part of a full-scale demonstration and to perform the clean up of
wastewater lagoon at the Anderson Development Company Superfund Site located in
Adrian, Michigan. The contaminate of concern in the lagoon was 4,4' methylene bis 2-
cMoroaniline commonly known as MBOCA. Roy F. Weston, Inc. (WESTON.) of West
Chester, PA, was contracted by Anderson Development Company to perform the
remediation of the lagoon and underlying soil. WESTON employed its patented (Patent No.
4,738,206) Low Temperature Thermal Treatment System (LT3) to treat the material. As
part of the consent order Anderson Development Company and WESTON prepared a
Remedial Action Plan, Health and Safety Plan and Quality Assurance Project Plan.
Following approval of these plans by United States Environmental Protection Agency (US
EPA) Region V and Michigan Department of Natural Resources, a demonstration test was
conducted as part of the US EPA Superfund Innovative Technology (SITE) program. A
rigorous testing program was conducted on eight process streams. The process streams were
sampled and analyzed for volatile organics, semivolatile organics, metals, dioxin and furans.
In addition, the stack emissions were sampled for particulate and hydrochloric acid to
determine if regulatory criteria were met.
Contaminate of Concern
MBOCA is a chemical intermediate used in the production of high-tech plastics and
urethane foams. MBOCA which is insoluble in water is a semivolatile with an extremely
low vapor pressure. MBOCA was present as a result of previous disposal operations. The
lagoon covered approximately 2 acres. The MBOCA was present in the sludge and
underlying naturally occurring clay in concentrations up to 1,600 ppm. A cleanup criteria
71
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of 1.6 ppm of MBOCA was established as the result of site specific risk analysis.
In addition to the contaminant of concern, the lagoon sludge also contained trace amounts
of other organic compounds including dichlorobenzene and toluene. The sludge also
contained a high concentration of manganese potassium permanganate which was added
during previous operations to oxidize the organics present in the lagoon.
LT3 System
The LT3 process is based upon indirect thermal heat exchanger. The screw type processor
is used to dry and heat the soil causing volatilization of the contaminates and moisture. The
process is capable of heating of the soils up to 580°F as was demonstrated during the
remedial activities at Anderson Development Company. By maintaining a constant exhaust
from the processor the evaporated water and organics are removed. The vented gases are
subsequently treated in a series of condensers. The condensers remove the bulk of the
evaporated moisture. The vapor stream is then treated by carbon adsorption packs and
exhausted to the atmosphere. The liquid phase generated in the condensers consists of
water and chemicals from the soil. The condensate is treated and either recycled as quench
water for the processed soil or shipped to an off-site treatment facility.
The LT3 is divided into three main processing areas: solids processing, emissions control and
wastewater treatment. A schematic diagram of the system is shown in Figure 1. The
general arrangement of equipment is shown in Figure 2. The LT3 equipment used on the
Anderson Development Company was mounted on three tractor trailers. The equipment
remained mounted on the trailers throughout operations.
Solid Handling System
The excavated soil and dewatered sludge from the lagoon was transported by track loader
to a double deck vibrating screen to remove debris greater than 2 inches. The screened
72
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material was then stockpiled. Awheel loader removed the screened soil from the stockpile
and fed the surge hopper. The wheel loader passed over a registered weigh scale to
determine total quantity of material treated. The surge hopper is maintained full to form
a seal at the inlet to the thermal processor
The thermal processor is constructed of two jacketed screw conveyors. The jacket and
screws are constructed with double walls that allow the circulation of a high temperature
heat transfer fluid. Each screw conveyor consists of four parallel intermeshed screws. The
two units are constructed in piggyback fashion. Intermeshing screws allow for improved
heater transfer and breaking up of soil. The high clay content soil at Anderson
Development Company did not cause balls to be formed. The screw conveyors are driven
by a variable speed drive which allows adjustment in soil discharge temperature and
residence time. During operations at Anderson Development Company the soil was
maintained at temperatures above 540 °F and residence times of 90 minutes.
The treated soil is discharged into a mixing screw conveyor. The mixing screw conveyor is
a ribbon flight conveyor where water is injected to quench and wet the soil. The material
is then stacked with a belt conveyor into daily storage piles.
Emissions Control
The volatilized organics and water from the LT3 are removed and passed through the
pollution control system. The exit gas which is typically maintained at 300°F. The gas is
drawn through a pulse-jet type baghouse dust collector. The dust collector removes
particulate matter. On a daily basis two to four drums of "fly ash" or dust are generated.
The gases are then drawn into an air cooled condenser. The air cooled condenser is a tube
type heat exchanger that uses force ambient air to indirectly cool the exhaust gases.
Temperatures exiting the air cooled condenser ranged from 125°F in summer to 40°F in
winter. The cooled exhaust gases then are drafted into a refrigerated condenser. In the
refrigerated condenser the exhaust gases are indirectly cooled to 60°F by a recirculating
73
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glycol and water solution. The glycol and water solution is maintain at 30 °F by a
refrigeration system. The exhaust gases are subsequently heated to 70°F by three inline
electric resistance heaters. By heating the exhaust gases to 70 °F the relative humidity of
gas is reduced to 70% preventing condensation in process piping and enhancing carbon
adsorption efficiency. The final emission control device is the carbon adsorption column.
Two standard carbon rental packs are used to treat the emissions prior to release. One
system is on line at all tunes. The second carbon pack is activated automatically if
breakthrough occurs.
Monitoring of the pollution control system effectiveness is provided by a Continuous
Emission Monitoring system (CEM). The CEM is used to monitor the exhaust stack for
concentrations of oxygen, carbon dioxide, carbon monoxide and total hydrocarbons. The
system also monitors the exhaust gases from the baghouse dust collector for oxygen and total
hydrocarbons.
Wastewater Treatment
The two condensers generate a liquid stream. The liquid consists primarily of water,
however, it also contains heavier organics. On the Anderson Development Project a simple
overflow decanter was used to separate out heavy condensate that contained high levels of
the insoluble MBOCA. The overflow was then filtered to remove entrained heavy. The
water was then treated by two carbon packs in series and stored in a 6,000 gallon tank. The
water at the Anderson Development project was then shipped off-site to an industrial waste
waster treatment plant for disposal.
Utilities
The operation of the LT3 requires the utilities which included 480 Volt electrical power,
natural gas and potable water. At previous operations the LT3 has used propane as a fuel.
74
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SITE Demonstration
The SITE demonstration was conducted in December 1991 on dewatered sludge from the
lagoon. The Application Analysis Report and results of the testing are currently undergoing
internal EPA review and are expected to be released shortly. The emission data from this
test have shown considerable control of organics and other pollutants.
The paniculate emission was on average less than 1.1 x KF* grains per dry standard cubic
feet. Similarly control of acid emissions were less than 6.0 X 10"5 pounds per hour.
Exceptional control of acid gases was expected since the LT3 is a desorption process and not
expected to generated destruction or combustion of chlorinated compounds.
The emissions of volatile organics were measured by a VOST sampling train. The total non
methane organic emissions were only 8.9 x 10"3 pounds per hour. Measurements of volatile
organics entering and exiting the carbon column demonstrated 95% removal of the volatile
organics by the carbon unit. Similar measurements on semivolatile organic compounds using
a Modified Method 5 sampling train demonstrated only 3.86 x 10~5 pounds per hour of
detectable semivolatile organics. The inlet and discharge streams of semivolatile organics
were used to measure a 98.4% removal of semivolatiles in the carbon bed.
Stack sampling using a Method 23 sampling train was also completed to determine the
emission of dioxins and furans. The emission of 2,3,7,8 TDCF and 2,3,7,8 TCDD were both
less than detection at <2.1 x 10'3 and <3.4 x 10'3 ng/dscm, respectively. The total emission
of TCDF was < 3.0 x 10'3 ng/dscm and total TCDD was determined to be 1.1 x -1 ng/dscm.
For further information, please contact Michael G. Cosmos, P.E., Project Director at (215)
430-7423 or Adolfo G. Murphy, Principal Project Manager at (215) 344-3724.
75
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Contaminated
soil storage
Clay Shredder
Oversize
material
Sweep gas
To atmosphere
Hot oil burner off-gases
Fuel/combustion air
Feed conveyor
Spray water
Makeup
water
Processed soil
dump truck
3-Phase
oil/water
separator
To backfill
excavation area
424-6340
To atmosphere
FIGURE 1 SCHEMATIC FLOW DIAGRAM OF THE LTl PROCESS
-------
Equipment
A. Thermal Processors
B. Fabric Filler
C. Process Control Trailer (Oflice)
D. Thermal Processor Drive Units
E. Hot Oil System
F. Air-cooled Condenser
G. Induced Draft Fan
H. Refrigerated Condenser
I. Vent Condenser
J. Glycol/Water Pumps
K. Glycol/Water Reservoir
L. Heater
M. Vapor Fan
N. Vapor Phase Carbon Columns
O. Oil/Water Separator
P. Liquid Phase Carbon Pumps
Q. Organic Collection Drums
R. Liquid Phase Carbon Columns
S. Clay Shredder
T. Drag Conveyor
U. Discharge Conveyor
V. Dump Truck
FIGURE 2 GENERALARRANGEMENT
OF LTi SYSTEM
-------
PLASMA ARC VITRIFICATION
Richard C. Eschenbach, Retech, Inc.
Abstract: The paper updates results obtained with Retech's Plasma
Centrifugal Furnace (PCF) process for treating hazardous waste. Data from
three SITE Demonstration tests with a PCF-6 in Butte, Montana, are
reported, as well as activities in Europe.
Process Concept: The Plasma Centrifugal Furnace (Figure 1) is a thermal
technology that uses heat generated from a plasma torch to treat
hazardous waste containing metals and/or organics. Metal-bearing solids
and soil are melted by the process, and organic contaminants are thermally
destroyed. The molten material forms a hard, glass-like leach-resistant
mass after cooling in a mold. The major elements of the process are the
feeder, plasma torch, rotating reactor well, afterburner, secondary
combustion chamber, and off-gas treatment system.
The process operates as follows: contaminated soil is placed in a bulk
screw feeder and gradually fed into the rotating reactor well. Solid
material is retained in the well by centrifugal force while a plasma arc
heats the material in an enriched oxygen atmosphere to temperatures
sufficient to melt soil (typically on the order of 3000°F). At this
temperature organic contamination is volatilized and burned. Any
incompletely burned gases or products of incomplete combustion formed
are incinerated by an afterburner located downstream of the reactor well.
Once a sufficient amount of feed material has been treated, the rotating
well is slowed, and the molten mass flows through a secondary chamber
into a slag collection chamber.
Initial tests with a lab-size Plasma Centrifugal Furnace having an 18"
diameter (=1.5 ft.) centrifuge (i.e. PCF-1.5) were conducted in the fall of
1987. Leach tests showed that the vitrified material which solidified in
the tub upon run termination was extremely leach-resistant (1).
The encouraging results from the lab-size unit led to acceptance of the
Retech process into EPA's second Superfund Innovative Technology
Evaluation (SITE) solicitation in 1988.
78
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In order to meet EPA's desire for a demonstration, rather than
development project, Retech designed and built a larger unit with a six foot
diameter centrifuge (PCF-6). In all PCF's, the centrifuge is located inside a
double-walled, water-cooled shell which can withstand substantial positive
or negative pressures without leakage. The PCF process is covered by two
U.S. patents (2).
Test Setup at Butte. Montana
Construction of the PCF-6 was completed in March of 1989, and a
preliminary test, supported by the EPA, was conducted at Ukiah April 25,
1989 with monitoring by Radian. The test disclosed problems with the
feeder and SCC temperature. Modifications were made, and ten additional
shakedown runs were made in Ukiah in May before the furnace was
disassembled and shipped to Butte.
The Component Development and Integration Facility (CDIF) of the U.S.
Department of Energy, in Butte, MT was picked as the test site for three
main reasons: 1) Butte had a Superfund location with pentachlorophenoi
contaminated soil leaving a high content of heavy metals - this
combination is readily treated with the PCF, 2) there was vacant lab space
at the CDIF with good support facilities, and 3) at that time the CDIF was
under the administrative supervision of the Idaho National Engineering
Lab (INEL) and INEL was interested in evaluating the utility of the PCF for
treating several different types of problem wastes at INEL.
About thirty shakedown tests were performed by MSE personnel between
October 1989 and June 1991 (MSE, Inc. is the M&O contractor for DOE at
the CDIF). Results of some of the shakedown tests have been reported (3).
During these shakedown tests, modifications were made to the original
system design. These modifications included the installation of an
afterburner in the secondary combustion chamber, the installation of a
chiller on the gas treatment system to compensate for this additional heat
input, and the elimination of the surge tank. In June the Environmental
Assessment was approved by both DOE and the EPA, and the SITE tests
were scheduled for the week of July 22, 1991.
The waste selected for treatment consisted of heavy metal-bearing soil
from the Silver Bow Creek Superfund site mixed with 10% by weight No. 2
diesel fuel. The mixture was spiked to provide 28,000 ppm of zinc oxide
and 1,000 ppm of hexachlorobenzene.
79
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Zinc was added as a tracer to determine the leachabiiity of the slag and the
hexachlorobenzene was the Principal Organic Hazardous Constituent (POHC)
used to determine organic Destruction and Removal Efficiency (DRE).
The entire process was controlled on the first level at a central control
panel. Here the torch operator, aided by T.V. monitors, controlled the
screw feeder and the position of the torch. Cameras were installed in
viewports attached to the primary chamber. All process parameters were
monitored by an automated Data Acquisition System (DAS) which collected
information every 30 seconds. Auxiliary equipment was monitored by
MSB personnel performing visual inspections and recording data every 30
minutes.
On Monday, 22 July 1991, furnace preheat started at 9:05 a.m. and feeding
of the first load commenced at 1:10 p.m. Four loads were fed, a pour was
made (277 pounds) and operations were shut down. On Wednesday, 24.
July 1991, furnace preheat started at 8:20 a.m. and feeding of the first load
commenced at 11:20 a.m. Exhaust fan problems limited the number of soil
loads to three (265 pounds of slag poured). On Friday, 26 July 1991,
furnace preheat started at 8:20 a.m. A water leak from the torch
protective sleeve interrupted the preheat; repair required three hours.
Preheat was again initiated at 12:40 p.m. and feeding of the first load
started at 3:50 p.m. Five loads were fed; feeding of the fifth load was
completed at 9:06 p.m. The melt was poured (595 pounds) starting at 9:23
p.m.
As part of the SITE Program, a sampling strategy was designed and
employed to evaluate the performance of the Plasma Centrifugal Furnace
technology developed by Retech, Inc. Samples were collected in
accordance with the "Demonstration Plan for Plasma Centrifugal Furnace
Technology" (4). Minor changes to the original sampling plan were made.
Figure 2 presents a schematic of the sampling locations for the
Demonstration Tests.
A somewhat more complete summary of the test procedure and the result
was given at the 1992 Incineration Conference (5). The detailed final
report appeared in two volumes (6, 7). An Applications Analysis Report
has also been issued by the EPA (8).
After the three SITE tests were completed, the PCF-6 at Butte was used to
treat surrogates of wastes now at INEL. These tests have been
summarized by MSE (9).
80
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Test Results at Butte
The Destruction and Removal Efficiency (DRE), used to determine organic
destruction, was determined by analyzing the feed soil and the stack gas
for the Principle Organic Hazardous Compound (POHC). For these tests, the
POHC was hexachlorobenzene, which is harder to destroy than PCB's. The
estimated mean level of hexachlorobenzene, based on ail the feed soil
samples for the three tests was 972 ppm. The 95% confidence interval for
the estimated mean was 864 to 1,080 ppm. No hexachlorobenzene was
detected in the stack gas; therefore, all DREs determined are based on the
detection limit from the appropriate tests. Table 1 gives the 95%
confidence interval for the DREs based on the confidence interval of the
feed soil and the detection limit for the particular test.
Table 1
DRE Results for Demonstration Tests
Hexach.loroben.zene
Test 1 I Test 1
1 Duplicate
Test 2
Test3
Lower 95% Confidence Interval >99.9964 >99.9982
Mean >99.9968 >99.9984
Upper 95% Confidence Interval >99.9971 >99.9986
>99.9990 >99.99989
>99.9991 >99.99990
99.9992 99.99991
As can be seen from Table 1, the estimated average DRE values for these
tests ranged from >99.9968% to >99.9999% for a highly chlorinated
compound, hexachlorobenzene. It can be reasonably assumed that this
level of DRE (if measurable) can be achieved for most chlorinated or
halogenated compounds.
Throughout each of the three Demonstration Tests, CO, C02, 02, NOX, and
total hydrocarbons (THC) were monitored continuously to present a real
time image of the combustion process and to determine if regulatory
standards were being exceeded. MSE, Inc. also monitored the same
combustion products for DOE during shakedown tests and other testing of
the PCF.
Since the installation of the afterburner in the secondary combustion
chamber, the level of total hydrocarbons exiting the system has been low
(<4 ppm) even with at least 10% organics in the feed soil.
81
-------
This gives a good indication that effective thermal destruction of the
organic compounds is occurring. Another indication of the ability of the
process to treat organic contaminated media is the low level of CO in the
exhaust (approximately 1.4 ppm) and the level of C02 (approximately 8%).
02 monitors show significant variation throughout the treatment process as
pure 02 is fed to the primary chamber at approximately 18 scfm while
waste is being fed to the furnace.
The PCF is designed to encapsulate inorganic compounds in the vitrified
slag and render the treated soil nonleachable. Testing activities have
demonstrated that the process can effectively bind inorganic compounds
into the treated soil. The Toxicity Characteristic Leaching Procedure (TCLP)
was performed on both the feed soil and the treated soil (i.e. slag). The
feed soil was tested to ensure that the material was leachable for organic
and inorganic compounds. The vitrified slag underwent TCLP to meet the
testing objectives. t
TCLP analysis of the feed soil for metals showed that the only elements
which exhibited significant leachabiiity characteristics were calcium and
the spiked zinc. The results of the TCLP metals analysis of the feed soil are
summarized in Table 2. The presence of sodium in the leachate is not
unexpected because of its high concentration in the soil and the fact that,
unlike other metals, it will have an affinity to go into solution. If the
solution is even slightly acidic (as in the TCLP) this phenomenon is
enhanced. None of the eight RCRA characteristic metals found in the feed
soil leachate were above the regulatory limit, therefore, the evaluation of
the leachabiiity of the vitrified slag was based on calcium and zinc.
Calcium was chosen, in addition to zinc, because of its tendency to leach
from the feed soil. During the Demonstration Tests, sodium was not used
in evaluating the soil leachabiiity because it is not typical of regulated
TCLP metals.
The treated soil TCLP metals analysis is also shown in Table 2. None of the
metals, with the exception of sodium, show any strong characteristic for
leaching. Sodium is probably present in the leachate for the reasons stated
above and is not considered in this evaluation. Both tracer metals, calcium
and zinc, showed significant reductions in leaching properties in the
treated soil as compared to the feed. In fact, all of the metals with the
exception of aluminum and iron showed reduced leaching characteristics.
The leachabiiity for the aluminum in both feed and treated soil is low and
the values reported for the treated soil are only estimates (less than the
quantity limit).
82
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Therefore, it is quite probable that the leachability of aluminum from the
feed soil to the treated soil did not change. The apparent increase in
leachability of iron in the treated soil occurred is because approximately
100 pounds of mild steel was placed in the furnace to aid in initiating the
arc. This considerably increased the iron content of the slag in comparison
to the feed soil.
The only organic constituents that were found to be leachable from the
feed soil were 2-methylnaphthalene and naphthalene. Although the feed
soil was spiked with a high level of hexachlorobenzene (1000 ppm), it did
not leach from the soil. No organic compounds were found to leach from
the treated slag.
The Toxicity Characteristic Leaching Procedure requires samples to be
ground into small particles. In this manner, a large amount of surface area
is available for leaching. Since the PCF produces a monolithic slag after
treatment, the surface area per pound of treated soil is much smaller than
that for the TCLP test. The TCLP results, therefore, present a conservative
assessment of the actual leachability of the monolithic slag.
83
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Table 2
TCLP Results for Demonstration Tests
Average
Compound Soil Lea
Concent
(mg/L)
Metals:
Treated Soil
Feed
chate
ration Test 1 Test 2
(mg/L) (mg/L)
Aluminum 0.23 J 0.45 J 0.41 J
Barium 0.14 0.08 0.08
Cadmium 0.07 ND ND
Calcium 175
Copper 4.6
2.1 J 2.5 J
0.15 0.35
Iron 0.06 2.5 2.95
Magnesium 8.12 ND ND
Manganese 4.82
Nickel 0.02
0.06 0.06
ND 0.01 J
Potassium 4.57 ND ND
Sodium 1475
Vanadium 0.1
Zinc 982
Semivolatiles:
1500 1400
ND ND
0.45 0.36
Mapthalene 0.397 ND ND
2-Methyinaph- 0.282 ND ND
thalene
JJeiachloro- ND
senzene
ND ND
Leachate
Test 3
(mg/L)
0.32
0.07
ND
2.05
0.3
31.1
ND
0.24
0.1
ND
1400
ND
0.3
ND
ND
ND
Concentration
Regulatory
Limit*
(mg/L)
J NR
100.0
1.0
J NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
0.13
ND - Not Detected
NR - Not Regulated
' - 40 CFR (07/01/90 Edition) §261.24, Table 2
J - Estimated result (less than five times the detection limit)
Note that slightly less than half the zinc was captured in the slag. If the
scrubber had been effective, the zinc not captured when charged could
have been subsequently re-charged.
The post-test scrubber liquor did not contain any significant quantities of
organic compounds. Nitrated compounds and phthalates were the only
compounds present. The nitrated compounds were most likely produced
from the high levels of NOX in the exhaust gas reacting with the water from
the scrubber and any organic compounds present.
84
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The phthalates and volatile organic compounds probably entered the
scrubber sump from the scrubber make-up liquor.
The lack of organic compounds in the scrubber liquor and, as stated earlier,
the absence of volatile or semivolatile organic compounds in the exhaust
gas, indicates that combustion of the organic compounds was complete.
The scrubbing unit was very inefficient in the capture of the inorganic
compounds. The scrubber did capture some of the volatile metal elements
but not at the levels that would typically be expected from a well-designed
system. As stated previously, the exhaust gas contained a variety of
metals that should have been captured by the scrubbing unit. The types of
metals found in the scrubber liquor were similar to those found in the
stack gas; that is, arsenic, iron, and zinc were the elements in abundance.
High sodium levels found in the liquor were probably a consequence of the
scrubber make-up (sodium hydroxide).
Results of the tests run by MSB for DOE after the SITE tests again showed
excellent TCLP results. Cerium was added as a surrogate for radioactive
compounds found in some INEL wastes; the mass balance for cerium was
inconclusive since less than half the feed cerium was accounted for (9).
Additional tests are planned.
Other Applications
In 1989 a Swiss firm, MGC Plasma ordered a PCF-8 furnace which was
installed in the summer of 1990 in Muttenz, a suburb of Basel (10). A gas
cleanup system built by Ceiicote was installed to permit the effluent to
meet the very strict Swiss standards. The furnace has a very unique
charging system: whole drums are inserted, five at a time, into a drum-
feeder chamber. A drum manipulator clamps the lid of the lead drum and
holds the drum in the furnace while an auxiliary cutting device opens up
the drum to dump the contents gradually into the furnace. There have
been some problems with this feeder and a different feed system is under
construction.
Retech is currently designing three more systems for three European
customers. One is a PCF-8 for treating soil contaminated with military
wastes. Most of the PCF feed in this application will arrive from a soil-
washing process which will enable at least 90% of the contaminated soil to
be returned as "clean" soil.
85
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The second is a PCF-8 for treating low/intermediate level radioactive
wastes. In this application, three categories of feed will be charged to the
furnace - organic liquids, combustible solids and metal waste. All three
categories will come to the furnace in 200 liter drums.
The third project is a smaller furnace, a PCF-2, which will be used to test
first radioactive surrogates, then radioactive mixed wastes. Figure 3 is a
schematic of this lab-size furnace.
Acknowlede ments
Much of the detail in this report came from the Butte SITE tests, and
special thanks are due to the co-authors of the paper summarizing this
work: Rob Haun of Retech, Corry Alsberg and Dan Battleson of MSB and
Trevor Jackson of SAIC. I am also grateful for the support of the EPA SITE
Demonstration Program which is conducted by the Risk Reduction
Engineering Laboratory. Ms. Laurel Staley was the Technical Project
Manager for the SITE tests.
References
1. J. W. Sears, R. A. Hill and R. C. Eschenbach, "Stabilization and
Decomposition of Toxic and Radioactive Wastes by Transferred-Arc
Plasma", 1989 Incineration Conference, Knoxville, TN
2. U.S. Patents 4,770,109 and 5,136,137
3. A. J. Viall, J. W. Sears, R. C. Eschenbach, "Test Results with the Plasma
Centrifugal Furnace", 1990 Incineration Conference, San Diego, CA
4. SAIC, Rev. 1, July 11, 1991
5. Rob Haun, R. C. Eschenbach, Dan Battleson, Corry Alsberg, Trevor
Jackson, "SITE Test Results with the PCF-6", 1992 Incineration
Conference, Albuquerque, New Mexico
6. "Technology Evaluation Report of Retech's Plasma Centrifugal
Furnace", Vol. I PB92-216 035-V1
7. "Technology Evaluation Report of Retech's Plasma Centrifugal
Furnace", Vol. 2 PB92-216 043-V2
8. Retech, Inc., Plasma Centrifugal Furnace, EPA Applications Analysis
Report, EPA/540/A5-9 1/007, June 1992
9. C. G. Whitworth, L. G. Twidwell, T. W. Jenkins and G. F. Wyss, "Slag
Chemistry and Metals Volatilization in the Plasma Arc Furnace
Experiment", Proceedings of Spectrum 92 - Nuclear and Hazardous
Waste Management International, August 1992, Boise ID
10. M. R. FUnfschilling, R. C. Eschenbach, "A Plasma Centrifugal Furnace
for Treating Hazardous Waste, Muttenz, Switzerland", Electrotech 92,
Montreal, Canada
86
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00
-0
FEEDER
SECONDARY
COMBUSTION
CHAMBER—
SLAG
CHAMBER
n
EXHAUST
STACK
PLASMA TORCH
ROTATING
REACTOR WELL
SURGE
TANK
GAS TREATMENT
\/^^^^^
FIGURE 1: COMPONENTS OF PCF SYSTEM
-------
SCREW
FEEDER
PR 1 MARY
CHAMBER
AFTER '
BURNER
SECONDARY
CHAMBER
00
00
VENT
TO
ATMOSPHER
STACK
BLOWER
JET
SCRUBBER
QUENCH
TANK
SAMPLE LOCATION
SCRUBBER
SUMP
CAUSTIC
RESERVOIR
FIGURE 2
SCHEMATIC OF SAMPLING LOCATONS
FOR THE DEMONSTRATION TESTS
-------
00
VO
REMOVABLE LID
FEEDER PORT
24 INCH I.D.
CENTRIFUGE
SLAG COLLECTION
MOLD
ROTARY
DRIVE
RP-75T PLASMA
TORCH
OFF-GAS TO SCC
4 INCH DIA. THROAT
FULL DOOR ACCESS
FOR CLEANING AND
SLAG REMOVAL
ROTARY WATER
JOINT
FIGURE 3: SCHEMATIC OF PCF-2
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THERMAL DESORPTION OF PCB-CONTAMINATED WASTE
AT THE WAUKEGAN HARBOR SUPERFUND SITE
(A CASE STUDY)
Joseph H. Hutton, P.E., Operations Manager
Robert Shanks, Technical Supervisor
SoilTech ATP Systems, Inc.
6300 South Syracuse Way, Suite 300
Englewood, Colorado 80111
(303) 290-8336
Abstract
In June 1992, SoilTech ATP Systems, Inc. (SoilTech) completed the soil treatment
phase of the Waukegan Harbor Superfund Project in Waukegan, Illinois, after approxi-
mately five months of operation. SoilTech successfully treated 12,700 tons of
polychlorinated biphenyl (PCB)-contaminated sediments using a transportable SoilTech
Anaerobic Thermal Processor (ATP) System nominally rated at 10 tons-per-hour (tph)
throughput capacity. The SoilTech ATP Technology anaerobically desorbs contami-
nants such as PCBs from solids and sludges at temperatures over 1,000 degrees
Fahrenheit (°F). Principal products of the process are clean treated solids and an oil
condensate containing the hydrocarbon contaminants.
At the Waukegan Harbor Superfund site, PCB concentrations in the sediments
excavated and dredged from a ditch, lagoon and harbor slip averaged 10,400 parts
per million (ppm) (1.04 percent) and were as high as 23,000 ppm (2.3 percent).
Treated soil contained less than 2 ppm PCBs and was backfilled in an on-site contain-
ment cell. The removal efficiency of PCBs from the soil averaged 99.98 percent,
relative to the project performance specification of 97 percent. Approximately 30,000
gallons of PCB oil, desorbed from the feed material, were returned to the potentially
responsible party (PRP) trust for subsequent off-site disposal. After modifications to
the emissions control equipment, compliance with the 99.9999 percent destruction
and removal efficiency (ORE) for PCBs in stack emissions required by the United
States Environmental Protection Agency was achieved. SoilTech demonstrated
compliance with the ORE requirement in eleven consecutive stack sampling events.
Feed rate averaged 8 tons-per-hour at a mechanical availability of 85 percent.
SoilTech revenues for the project were $700,000 in fixed costs and $185 per ton of
soil processed.
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THERMAL DESORPTION OF PCS-CONTAMINATED WASTE
AT THE WAUKEGAN HARBOR SUPERFUND SITE
(A CASE STUDY)
By
Joseph H. Hutton, P.E., Operations Manager, SoilTech ATP Systems, Inc.
Robert Shanks, Technical Supervisor, SoilTech ATP Systems, Inc.
1.0 INTRODUCTION
This technical paper outlines SoilTech's role in the Waukegan Harbor Superfund
Project. SoilTech was responsible for the soils processing phase of the project using
its unique rotary kiln known as the SoilTech Anaerobic Thermal Processor (ATP)
Technology to remediate the PCB-contaminated soils and sediments. The Waukegan
Harbor Project is the second commercial application of the SoilTech ATP Technology.
42,000 tons of PCB contaminated soils were successfully treated to nondetect levels
at the Wide Beach Superfund site in western New York in 1990 and 1991. The ATP
distills organic contaminants out of a solid matrix in an oxygen-free environment.
Oxidative degradation of contaminants such as PCBs into more harmful reaction
products is therefore prevented. Contaminants are collected in an oily condensate
which can then be economically disposed of.
Section 2.0 of this paper describes the technology and Section 3.0 discusses
treatment costs. Section 4.0 summarizes SoilTech's activities at the Waukegan
Harbor site.
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2.0 SOILTECH ATP TECHNOLOGY DESCRIPTION
The ATP Technology was originally conceived as a means to perform primary refining
of tar sands and oil shales to crude oil in the early 1970s. UMATAC Industrial
Processes (UMATAC) developed and tested the technology over a period of more than
15 years with funding from the Alberta Oil Sands Technology Research Authority
(AOSTRA). The technology has been further developed to handle a wide range of
organic contaminants such as PCBs. In 1988, Canonie Environmental Services Corp.
(Canonie) entered into an exclusive license agreement to utilize the technology for
waste treatment in the United States. Together, Canonie and UMATAC, as equal
partners, formed SoilTech. The technology, now known as the SoilTech ATP
Technology, is described below. Specific fundamental elements of an ATP plant
include the ATP System, the vapor handling equipment, the air pollution control
equipment, and the control room. Each of these elements is described below.
2.1 Anaerobic Thermal Processor
The central element of the ATP Technology is the processor itself which resembles
a rotary kiln from its exterior. However, inside the processor are three physically
distinct zones and four zones characterized by different physical processes. The four
process zones are described as the following:
1. Preheat zone;
2. Retort zone;
3. Combustion zone; and
4. Cooling zone.
Figure 1 is a cross section of the ATP which depicts each of the four zones. The form
and function of each of the zones are described below.
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2.1.1 Preheat Zone
As indicated on Figure 1, the preheat zone is the first zone of the ATP into which feed
material is conveyed. The preheat zone is charged with feed material by a system of
variable-speed material conveyors and feed hoppers as indicated on the process flow
diagram shown on Figure 2. The preheat zone is a cylindrical compartment oriented
centrally along the axis of the ATP. It is indirectly heated by conduction of thermal
energy from hot treated material exiting the processor through the cooling zone.
The material fed to the preheat zone is raised from ambient temperature to
approximately 500°F as the material travels through the preheat zone. Any light
hydrocarbons and moisture present are distilled out of the feed material and evacuated
through a vapor pipe mounted in the fixed endframe of the preheat zone (see
Figure 1). The blowers and dampers used to evacuate the vapors from the preheat
zone are configured to maintain a negative pressure of approximately 0.10-inch water
column relative to atmospheric pressure.
When material reaches the end of the preheat zone, it exits by passing through, a
circumferential grizzly and entering the proprietary sand seals before being conveyed
into the retort zone. The proprietary sand seals allow conveyance of solid material
while prohibiting the passage of vapors. This allows the retort zone to be maintained
in an anaerobic condition.
2.1.2 Retort Zone
The ATP retort zone is a cylindrical chamber oriented along the axis of the processor
at the discharge end of the preheat zone. Material enters the retort zone from two
sets of sand seals. The first set conveys preheated material from the preheat zone
into the retort zone, as previously described. The second set conveys treated material
from the combustion zone back into the retort zone. This hot recycled material
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provides the necessary thermal energy to raise the temperature of the bulk solid
i
mixture in the retort zone to temperatures of 950°F to 1,150°F. The sand seals
prevent the passage of oxygen into the retort zone and also prevent contaminated
vapors from passing into the combustion zone from the retort zone.
Solid material exits the retort zone through a third set of sand seals into the
combustion zone, as indicated on Figure 1. Heavy hydrocarbons, which enter the
retort zone on the material entering from the preheat zone, are quickly vaporized,
producing hot, decontaminated, inert solids. The distilled hydrocarbon vapors are
evacuated from the retort zone through a vapor pipe mounted through the stationary
endframe at the combustion end of the processor. The evacuated vapors are
conveyed to a system of condensing equipment. The blowers and dampers employed
to evacuate vapor from the retort zone are configured to maintain a negative pressure
of approximately 0.12-inch water column relative to atmospheric pressure.
2.1.3 Combustion Zone
The combustion zone of the ATP makes up the annular space between the inner wall
of the processor and the outer wall of the retort zone bordered by the stationary
combustion endframe and the cooling zone. As shown on Figure 1, there is no
physical barrier between the combustion zone and the cooling zone.
Treated material enters the combustion zone from the discharge sand seal of the retort
zone. Accelerator flights reverse the direction of material flow back toward the feed
end of the ATP unit. Lifting elements lift and drop the treated soil into the combustion
flue gases. Temperatures of around 1,400°F are maintained by two natural
gas/propane burners that are fired into the combustion zone through the processor
endframe. A portion of the heat requirements of the system are provided by the
oxidation of any coke present on the decontaminated solids and light, noncondensable
hydrocarbons returned to the combustion zone from the vapor condensing systems.
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As the hot treated material nears the entrance to the cooling zone, a fraction is
diverted back into the retort zone through the recycle sand seals described previously.
This recycled treated material provides the thermal energy necessary to achieve the
required desorption temperatures in the retort zone. The material that is not diverted
into the retort zone passes through to the ATP cooling zone.
2.1.4 Cooling Zone
The cooling zone is a continuation of the combustion zone. It is the annular space
between the inner wall of the processor and the outer wall of the preheat zone. In the
cooling zone, treated material continues to be lifted and dropped into the flue gases
and onto the exterior wall of the preheat zone. Thermal energy is thereby transferred
by conduction through the preheat zone wall to the incoming feed material in the
preheat zone while cooling treated material in the cooling zone. When material
reaches the end of the cooling zone, it falls through a stationary grizzly into a screw
conveyor.
2.2 Auxiliary Systems
The ATP is supported by various auxiliary systems which employ well-established
technology, most of which have been proven over many years in a wide range of
industrial applications. A simplified process flowsheet for the ATP Technology is
provided on Figure 2. A more detailed process flowsheet is included as Figure 3.
Each of these auxiliary systems is described in detail below.
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2.2.1 Vaoor Handling Equipment
The ATP plant contains two separate gas-handfing trains to process the vapors
generated in the preheat and retort zones. The basic function of each of the trains
is to remove particulate matter and cool the vapors such that water and hydrocarbons
are condensed.
2.2.2 Preheat Vapor Handling Equipment
Steam and light hydrocarbons are removed from the preheat zone through a cyclone
separator to remove particulate matter and then through a water-cooled shell and tube
heat exchanger. The liquids condensed in the shell and tube heat exchanger gravity
drain into an oil/water separator. Water collected in the separator is pumped to stor-
age and subsequent treatment. Oil collected in the separator is pumped to storage
for subsequent disposal off-site or can be used for reflux in the retort zone's vapor
handling equipment. Any noncondensable gases are passed through activated carbon
and then into the combustion zone.
2.2.3 Retort Zone Vapor Handling Equipment
The hydrocarbon vapors and contaminants, such as PCBs, are removed from the retort
zone and pulled through a vapor scrubber which removes particulate material too fine
for removal in the upstream cyclones and cools the vapors from over 1,000°F to
approximately 400°F. The vapor scrubber is a direct-contact condensing tower which
relies on closed-circuit pumping to circulate oil countercurrent to the vapor flow. The
condensed oils and contaminants are pumped to storage for subsequent disposal off-
site. Most of the PCBs are condensed in the vapor scrubber.
Vapors exiting the vapor scrubber are pulled through the fractionater. The f ractionater
is identical to the vapor scrubber but operates at lower temperatures and cools the
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vapors to approximately 250°F. Condensed oil can either be pumped to the vapor
scrubber or directly to storage.
The vapors which exit the fractionater are pulled through a water-cooled shell and
tube heat exchanger identical to the one used in the preheat system. The condensed
liquids gravity drain into a two-phase separator. The water phase is pumped from the
separator to storage for subsequent treatment. The oil phase is pumped into the
fractionater or vapor scrubber as a means of temperature and oil level control.
Noncondensable vapors are passed through activated carbon to remove residual heavy
hydrocarbons and then onto the combustion zone of the ATP through the combustion
endframe.
2.2.4 Air Emissions Control Equipment
The combustion gases are pulled under vacuum from the cooling zone by two
induced-draft fans through a cyclone separator, a quench tower, two baghouses
operated in parallel, and an activated carbon bed. The relatively low gas flow rate and
temperature assure thorough removal of particulates and residual hydrocarbons.
2.2.5 Material Handling Systems
The ATP Plant includes two independent solid handling systems for feed handling and
treated soil handling.
The feed handling system is designed to provide solid feed material to the ATP during
steady-state waste treatment operations and to provide clean sand feed to the ATP
during startup, shutdown or upset conditions. As indicated on Figure 3, the feed
system consists of two hoppers equipped with apron belt conveyors, either of which
can feed a belt conveyor that transports contaminated feed or clean sand into the
preheat zone.
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The treated soil handling system conveys treated soil from the base of the cooling
plenum via a soil conditioner equipped with water sprays and onto a conveyor belt.
2.2.6 Process Waste water Treatment System
The ATP Plant produces aqueous condensate at a rate equal to the rate that moisture
enters the processor with the feed soil. At the Waukegan Harbor site, the ATP
System produced 6 gallons-per-minute (gpm) or less of aqueous condensate which
required treatment. The water was pumped from the phase separators into storage
tanks and then through the on-site treatment system operated by Canonie. The
treatment system is designed to process up to 25 gpm.
The treatment system relies on filtration, oxidation, and adsorption operations to
remove contaminants from the aqueous condensate. Specific treatment steps include
sand filtration, Klensorb® filtration, ultraviolet enhanced oxidation, cartridge filtration
to 0.5 microns, and activated carbon filtration through multiple beds in series. The
treated water can be pumped to the process water storage tanks for subsequent use
in the plant. However, at Waukegan Harbor treated water was discharged to the sani-
tary sewer.
2.2.7 The Control Room
The plant control systems and electrical hook-ups are housed in the control room
trailer. Extensive use of microprocessor technology for process control and logic
functions allows one lead operator to run and monitor the plant from the control panel
with the assistance of two technicians in the field. All process parameters such as
temperatures, flowrates, pressures, tank levels, equipment current draws, and flue gas
quality are monitored and recorded.
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2.3 ATP Plant Utility Requirements
The ATP Plant requires electricity, fuel (natural gas or propane) and nitrogen in
addition to process water. Specifically, the plant consumes an average of 210 KVA
electricity, eight million BTU-per-hour of fuel, and 15,000 cubic feet-per-week of
nitrogen.
2.4 Staffing
The ATP System runs on a three-shift, 24-hour-per-day basis with an operating crew
of three or four people comprised of one lead operator and two or three assistant
operators working in the field. Three or four maintenance personnel work day shift
five days a week. A Project Superintendent, Project Engineer, Site Safety Officer, and
Receptionist are also on-site during day shift hours.
2.5 Health and Safety
At the Waukegan Harbor site the ATP System was located inside the exclusion zone.
Level D personal protective equipment (PPE) was used during plant set-up. An
upgrade to Level C was required as soon as processing began. The control room was
positioned in the support zone adjacent to the exclusion zone, allowing the lead
operator to work in street clothes.
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3.0 TREATMENT COSTS
Costs for treatment using the 10-tph SoilTech ATP System can vary depending on the
character of the waste material, ranging from $150 per ton to $250 per ton. Costs
depend mainly upon the following variables:
• Moisture content of feed material;
• Particle size;
• Hydrocarbon content;
• Material handling characteristics; and
• Chemical characteristics.
Mobilization and demobilization costs for the 10-tph SoilTech ATP System range from
$700,000 to $1.5 million.
As illustrated on Figure 4, the smaller 5-tph SoilTech ATP is generally more cost-
effective for projects of 5,000 tons or less, while the larger 25-tph ATP System is
more cost-effective for project of greater than 45,000 tons.
3.1 Moisture Content of Feed
Feed moisture content is a rate-limiting parameter related linearly to plant throughput
and therefore to the price of treatment. Ideal moisture content in feed material is in
the range of 5 to 10 percent. At lower moisture contents, entrained dust can create
problems in the vapor condensing systems. At moisture contents above 10 percent,
the latent heat required to distill the moisture from the feed in the preheat zone of the
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ATP System can become rate limiting. SoilTech evaluates, and when appropriate,
incorporates predrying of feed material into a project work plan when waste moisture
content might affect treatment economics.
3.2 Particle Size
Material should be smaller than 2 inches; if not, pre-screening and/or crushing may be
necessary. Where a material contains a high percentage of very fine material such as
clay, co-feeding of coarse material may be necessary. Fine material tends to reduce
the efficiency of the sand seals and will be drawn out of the processor with the flue
gases, reducing the quantity of material available for heat transfer in the combustion
and cooling zones.
3.3 Hydrocarbon Content
The SoilTech ATP System is designed to handle feed materials containing up to 10
percent hydrocarbons. With higher levels or where a substantial proportion of those
hydrocarbons have a high molecular weight and amenable to cracking, the amount of
coke formed in the retort zone may be excessive. Elevated levels of carbon monoxide
in the flue gas stream may then result. Reducing feed rate or incorporating an
additional flue gas treatment step, such as catalytic oxidation, mitigates the problem
but increases treatment costs.
3.4 Chemical Characteristics
A feedstock exhibiting unusual reactivity, corrosivity or toxicity may require pre-
treatment or special handling precautions. Treatment cost would therefore be
affected adversely.
10.1
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3.5 SoilTech Bench-Scale Unit
SoilTech is able to accurately predict treatment performance and costs based on
bench-scale testing results. The bench test unit accurately simulates conditions in the
full-scale system. Over 2,000 bench-scale tests have been conducted on a variety
of contaminated materials. Strict procedures and protocols have been developed and
are rigorously applied.
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4.0 WAUKEGAN HARBOR SUPERFUND PROJECT DESCRIPTION
The Waukegan Harbor Superfund site was listed on the EPA's Superfund Priority List.
Contamination resulted from leakage of PCBs - used as an aluminum casting lubricant
and machine tool lubricant - through floor drains from a major manufacturing facility
into an adjacent stream and Waukegan Harbor. PCB concentrations in excess of
20,000 ppm were found in the harbor sediments and stream bed. Remediation of the
site was complicated by the fact that the harbor was being used for both commercial
and recreational boating activities and was adjacent to a public beach. The client
insisted that operations not impact the day-to-day activities of the local community.
It was therefore necessary for Canonie, the prime contractor, to build a new boat slip
prior to isolating the old one. Sediments with PCB concentrations greater than 500
ppm were hydraulically dredged from the old slip and pumped to a containment cell
where dewatering was achieved before they were blended with soils from the conta-
minated stream bed.
The 1984 Record of Decision (ROD) called for stabilization of these soils and
sediments. However, SoilTech and the PRPs were able to convince the EPA that the
use of SoilTech's ATP Technology offered a more environmentally acceptable and
cost-effective solution. The EPA accepted that the SoilTech ATP System was an
innovative treatment technology that provided a significant and permanent reduction
in the toxicity and volume of PCB wastes at the Waukegan Harbor site. SoilTech's
approach fulfilled the requirements of the Superfund Amendments and Reauthorization
Act (SARA). Under the 1984 ROD, there would have been a potential future liability
posed by stabilized stored wastes.
SoilTech was contracted by Canonie to process the soils and sediments for $700,000
in fixed costs and $185 per ton of material processed. SoilTech was not responsible
for providing utilities (water, gas and electricity). Site preparation and excavation of
contaminated material were carried out by Canonie. The PRPs took full responsibility
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for disposing of the PCB condensate produced. Had SoilTech been responsible for any
or all of these additional activities, the unit price for soils processing would have been
correspondingly higher.
The project clean-up criteria called for a treated soil residual PCB level of 500 ppm,
or 97 percent removal efficiency from the soils, whichever was more stringent. The
average target clean-up level turned out to be approximately 310 ppm. Total soils
requiring treatment amounted to about 12,700 tons. Treated soils were to be placed
in one of two containment cells along with untreated soils containing less than 500
ppm PCBs before being closed with a Toxic Substances Control Act (TSCA)-approved
impermeable cap. PCB-contaminated oils extracted from the soils were returned to
the PRPs for subsequent disposal.
Since no applicable air emissions standard exists for thermal desorption, the EPA
required that SoilTech meet the 99.9999 percent (6 nines) destruction and removal
efficiency (ORE). SoilTech was also required to meet the municipal waste incineration
standard of 30 nanograms per dry standard cubic meter (ng/dscm) total dioxins and
furans applied to incineration of PCB-contaminated wastes. Discharged water was
to be less than 15 parts-per-billion (ppb) PCBs.
4.1 Sequence of Events
SoilTech arrived at the Waukegan Harbor Superf und site in the last week of November
1991. Modification and repair of key process components continued at a shop in
Indiana while the site was prepared, and support equipment was assembled and
erected. Shakedown and troubleshooting of the SoilTech ATP System was conducted
in mid-January. SoilTech began treating contaminated soils and sediments on
January 22, 1992. This date also marked the start of the 30-day proof-of-process
period.
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Between startup and March 6, 1992, the SoilTech ATP System averaged a feed rate
of 10 tph, outperforming initial projections of 9 tph. Net plant availability was over
85 percent. PCB concentrations in the feed averaged 14,000 ppm and treated soil
concentrations less than 2 ppm PCBs were attained. The average removal efficiency
from the treated soil was 99.96 percent.
During this time period, SoilTech performed seven stack tests. Although the
emissions criteria for dioxins and furans were met, SoilTech was unable to meet the
6 nines ORE for PCBs and consequently stopped operations at the direction of the
EPA.
During the next two months, SoilTech operated the ATP System intermittently to test
various modifications to the ATP and to the emission control system. Specific
modifications included:
• Increasing the volume of carbon in flue gas carbon bed;
• Removing the wet scrubber from the flue gas handling system;
* Adding carbon beds to internal gas recycle streams;
• Testing of continuous addition of powdered activated carbon upstream of
the baghouses to facilitate adsorption of PCBs;
• Reducing flue gas carbon bed temperature; and
• Testing of continuous addition of sodium bicarbonate in the combustion
zone of the ATP in an attempt to induce catalytic destruction of residual
PCBs.
In the latter phase of this period of intermittent operation and testing, SoilTech
discovered a gap in the flue gas carbon bed seal which was allowing 70 percent of
the flue gas stream to bypass the carbon bed. SoilTech corrected the poor seal before
stack testing on May 12, 13, and 14, 1992.
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Each of four stack tests conducted on those three consecutive days demonstrated
performance superior to the 6 nines ORE required. A summary of the stack testing
conducted throughout the project is given in Table 1.
It appeared that the final three tests, using powdered activated carbon in the
baghouse and then soda ash in the combustion zone, produced slightly better results
than the test conducted without these additives. The results are, however,
statistically inconclusive.
With EPA's approval SoilTech was then able to resume processing the contaminated
soils and sediments having met all of the project performance criteria.
To insure that this performance was maintained, SoilTech instituted several new
procedures and operating conditions.
• Soda ash was fed to combustion zone at 200 Ibs/hour;
• Stack temperature was maintained at 170°F with automatic waste feed
shut off at 190° F;
• The stack gas carbon bed was sampled on a daily basis. The plant was to
be shut down and the carbon bed changed when the PCB concentration
exceeds 10 ppm;
• Weekly stack testing were performed by Clean Air Engineering. Failure to
meet 6-nines ORE would necessitate immediate shutdown until the cause
had been identified and remedied; and
• The pressure drop across the stack carbon bed was maintained. The bed
was to be inspected if it drops below 5-inches water column.
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4.2 EPA Site Demonstration
On June 16, 1992 the EPA began a Superfund Innovative Technology Evaluation
(SITE) demonstration of the SoilTech ATP System. This involved three days of
rigorous sampling and testing. The test runs were conducted at typical operating
conditions. The fourth and final test was, however, run without the addition of soda
ash to the combustion zone. The other three tests were run while 200 Ibs/hr of soda
ash was added to the combustion zone. Each test run consisted of 8.5 hours of
solids and liquids sampling and 8 hours of stack sampling. During the site
demonstration, 224 tons of PCB-contaminated soils and sediments were processed.
In addition to sampling, data on critical operating parameters were collected during
each test.
Based on the preliminary results at the site demonstration, the EPA concluded the
following:
« PCS concentrations were reduced from an average of 9,761 ppm in the
untreated soil and sediment to an average concentration of 2 ppm in the
treated soil and sediment.
• Approximately 0.12 milligram (mg) of PCBs was discharged from the ATP
System's stack per kilogram of PCBs fed to the ATP.
* The majority of PCBs removed from the untreated soil and sediment were
accumulated in the waste oil discharge from the vapor cooling system.
• No dioxins, other than a low concentration 0.1 ng/dscm of octachlorinated
dibenzo-p-dioxin in one stack gas sample, were detected in the stack gas
from the ATP System. Tetrachlorinated dibenzofurans were found in both
the untreated soil and sediment (88 ng/g) and treated soil and sediment (5
ng/g) and the stack gas (0.07 ng/dscm).
9 Leachabie volatile organic compounds, semivolatile organic compounds, and
metals in the treated soil and sediment were below Resource Conservation
and Recovery Act (RCRA) toxicity characteristic standards.
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• No operational problems affecting the ATP's ability to treat the
contaminated soil and sediment were observed.
Selected results provided by the EPA are presented in Table 2. As expected, the
results confirm that SoilTech met all of the project performance criteria. Removal
efficiency for PCBs in the treated soil averaged 99.98 percent. ORE for the stack
emissions exceeded the 6 nines criteria in each test and bettered 7 nines in two of the
tests.
The results also demonstrated that dioxins and furans are not produced in the ATP.
Trace amounts detected in the waste oil, the treated soil and stack gas can be traced
back to the untreated soils and sediments.
The highest DRE for PCBs in the stack was achieved for the test in which no soda ash
was added to the combustion zone of the ATP. This indicates that the addition of
soda ash provides no reduction in the flue gas emissions produced by the SoilTech
ATP System. Further bench testing might, however, provide a more statistically
conclusive evaluation.
Processing of soils and sediments at the Waukegan Harbor site continued without
further incident and was successfully completed on June 23, 1992 when a total of
12,700 tons had been processed. A summary of production data is provided in
Table 3. Approximately 30,000 gallons of PCB-contaminated oil was desorbed from
the soils and sediments and returned to the PRPs for subsequent off-site disposal. An
average plant throughput of 8 tph had been achieved with a mechanical availability
of 85 percent.
Process water generated during operations was discharged to Canonie's water
treatment system at approximately 5 gpm and released to the sewer at a PCB
concentration of less than 15 ppb PCBs.
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5.0 CONCLUSIONS
The Waukegan Harbor Superfund Project was the SoilTech ATP Technology's greatest
challenge to date due to the high concentrations of PCBs in the feed material. System
modifications allowed the strict project performance criteria to be met and surpassed.
The SoilTech ATP Technology has demonstrated the capability to:
• Provide a significant and permanent reduction in the toxicity and volume of
PCB wastes at Waukegan Harbor,
• Reduce PCB concentrations in the soils and sediments from as high as 2.3
percent to below 2 ppm,
• Achieve a 7-nines PCB ORE in the stack gases,
• Meet or exceed all project performance criteria, and
• Provide a cost-effective and more environmentally favorable alternative to
established technologies.
109
-------
References
Montgomery, A. H., C. J. Rogers, and A. Kernel, 1992, "Thermal and Dechlorination
Processes for the Destruction of Chlorinated Pollutants in Liquid and Solid Matrices",
AlChE 1992 Summer Annual Meeting, August 9-12. Minneapolis, Minnesota.
Vorum, M., 1991, "SoilTech Anaerobic Thermal Process (ATP): Rigorous and Cost
Effective Remediation of Organic Contaminated Solid and Sludge Wastes", AWMA
Conference. Kansas City, Kansas, June.
Vorum, M., and A. H. Montgomery, "The Taciuk Process Technology for Anaerobic
Pyrolysis of Solid Wastes and Sludges". Conference on Hazardous Waste Research,
Kansas State University, Manhattan, Kansas.
110
-------
TABLE 1
STACK TEST SUMMARY
WAUKEGAN HARBOR
Date
01-28-92
02-04-92
02-11-92
02-18-92
03-04-92
03-05-92
03-05-92
03-18-92
04-09-92
04-10-92
05-12-92
05-13-92
05-13-92
05-14-92
06-02-92
06-02-92
06-09-92
06-16-92
Feed PCBs
(#/hr)
192.50
215.50
213.40
155.70
105.60
100.80
100.80
174.90
148.60
298.50
230.40
264.60
183.00
205.70
167.40
213.60
159.15
140.80
Stack PCBs
(#/hr)
0.0144000
0.0932000
0.0690000
0.0087600
i
0.0039700
0.0012700
0.0007720
0.0009890
0.0034500
0.0009430
0.0002000
0.0000735
0.0000464
0.0000448
0.0000942
0.0001850
0.0000432
0.0000050
PCB ORE
•(%)
99.9925195
99.9567517
99.9676664
99.9943738
99.9962405
99.9987401
99.9992341
99.9994345
99.9976783
99.9996841
99.9999132
99.9999722
99.9999746
99.9999782
99.9999437
99.9999134
99.9999729
99.9999964
NOTE:
1. PCB Destruction Removal Efficiency (ORE) criterion is 99.9999 percent.
Ill
-------
TABLE 2
EPA SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION
DRAFT RESULTS
Waste Feed
Contaminant Concentrations
Contaminant
Total PCBs
Dioxin/Furan:
TCDF
PeCDF
Average Concentration
9231 ppm
86 ppb
16 ppb
Treated Soil
Contaminant Concentrations
Contaminant
Total PCBs
Dioxin/Furan:
TCDF
Average Concentration
1.972 ppm
5.4 ppb
Waste Discharge Oil
Contaminant Concentrations
Contaminant
Total PCBs
Dioxin/Furan:
TCDF
PeCDF
Average Concentration
32%
136 ppb
14 ppb
112
-------
TABLE 2
EPA SUPERFUND INNOVATIVE TECHNOLOGY EVALUATION
DRAFT RESULTS
(Continued)
Stack Gas
Contaminant Concentrations
Contaminant
Particulates
Total PCBs
Total TCDF
HCL Gas
Total Hydrocarbons
Average Concentration
0.0039 jjg/dscm
0.8330 //g/dscm
0.0790 ng/dscm
23.000 //g/dscm
ND
Output
(Ibs/hr)
0.071
1.7E-5
1.4E-9
0.00042
0
Emissions
Criteria
8.7 Ib/hr
30 ng/m3
0.2 Ib/hr
Stack Gas Emissions
Destruction and Removal Efficiencies
Test Run No.
1
2
3
4
PCBs Fed to ATP
(Ib/hr)
140.60
136.87
153.73
181.71
PCBs Exiting Stack
(Ib/hr)
18.9E-6
14.27E-6
17.15E-6
8.09E-6
ORE
(%)
99.999987
99.999990
99.999989
99.999996
NOTE:
1. Project emissions criteria for PCBs is 99.9999% ORE.
113
-------
TABLE 3
PRODUCTION DATA
WAUKEGAN HARBOR
Week
Ending
1-25-92
2-01-92
2-08-92
2-1 5-92
2-22-92
2-29-92
3-07-92
3-21-92
4-11-92
4-18-92
5-16-92
5-30-92
6-06-92
6-13-92
6-20-92
6-27-92
TOTAL
Production
(tons)
561
1,476
1,202
1,205
1,493
606
841
245
483
592
377
46
1,284
1,000
887
402
12,700
Average PCS in
Feed Soil
(ppm)
15,500
9,243
11,657
13,143
9,571
7,025
7,060
9,950
8,350
13,740
8,800
1 2,000
10,486
9,450
9,917
9,300
10,400
Average PCB
Removal
Efficiency (%)
99.97
99.95
99.98
99.98
99.98
99.98
99.99
99.97
99.97
99.99
99.99
99.99
99.98
99.98
99.99
99.95
99.98
NOTE:
1. Soil treatment criterion is 97 percent removal efficiency.
114
-------
MINIMAL
EMISSIONS
SYSTEM
LOW TEMP. STEAM
AND HYDROCARBON
VAPORS FLOW
FEED STOCKS
SAND SEAL
PRODUCT
RECOVERY
SYSTEM FOR
RECYCLE
HYDROCARBON
— ——•*• AND STEAM
VAPORS FLOW
COMPATABILITY
WITH MIXED
FEEDS
CONTINUOUS
PROCESS
SYSTEM
SPENT SOLIDS
TAILINGS
KILN END SEALS (IYP.)
AUXILIARY
BURNERS
COMBUSTION
AIR FLOW
SINGLE STEP
FEED TREATMENT
SELF-SUSTAINING
HEAT SYSTEM
HEAT TRANSFER
MECHANISM
FIGURE 1
SOILTECH ATP CROSS SECTION
-------
STACK
GAS
TREATMENT
PCB
CONTAMINATED
FEED
PREHEAT
VAPOR
ANAEROBIC
THERMAL
PROCESSOR
TREATED
SOLIDS
PCB
CONTAMINATED
OIL
i
VAPOR
TREATMENT
AIR
FUEL
WATER
WATER
TREATMENT
NON
CONDENSABLE
GAS
ORGANIC
VAPOR
TREATED
WATER
SOUR
WATER
OIL
RECOVERY
PCB
PRODUCT
OIL
FIGURE 2
SOILTECH ATP TECHNOLOGY SIMPLIFIED FLOW DIAGRAM
-------
FLUE GAS
SCRUBSfR
T-400TF
J I T-«T,
1 FUE C*S I
I BACHOUSE I
vvv
CYCUONE
T-100O"F
r~
SCRUBBER
CONDENSED
r ^
$
TMUNGS PILE
FIGURE 3
SOILTECH ATP TECHNOLOGY PROCESS FLOW SHEET
-------
00
5 TPH
o
3
12
10
8
MOST ECONOMICALLY FAVORABLE ATP
10 TPH 25 TPH
O
O
UJ
o:
a.
0
T
T
.SEE MOB/DEMOB $AON
5 TPH $500.000 $300
10 TPH $1.000.000 $200
25 TPH $3,250.000 $150
• » -' - -. . ",•••. • »•• : . t-
.. - »«•»*. . . •. •
- .. > ;,.- • •, . r . . .
10
20
30
40
50
60
QUANTITY OF CONTAMINATED MATERIAL
(THOUSANDS OF TONS)
70
FIGURE 4
EVALUATION OF OPTIMUM SIZE ATP UNIT
-------
THE BABCOCK & WILCOX CYCLONE VITRIFICATION
TECHNOLOGY FOR CONTAMINATED SOIL
J. M. Czuczwa, H. Farzan, W. F. Musiol, J. J. Warchol, S. J. Vecci
Babcock & Wilcox R&DD, 1562 Beeson Street, Alliance, Ohio 44601
INTRODUCTION
Technology Development at Babcock & Wilcox
The Babcock & Wilcox cyclone furnace is a well-established
design (over 26,000 MW installed electrical capacity) for the
combustion of high inorganic (ash) coal. The combination of high
heat release rates (450,000 Btu/cuft for coal) and high turbulence in
cyclones assures the high temperatures required for melting the high
ash fuels. The inert ash exits the cyclone furnace as a vitrified
slag.
Taking advantage of the ability of the cyclone furnace to form a
vitrified slag from waste inorganics, the cyclone furnace was used in
a research and development project to vitrify municipal solid waste
(MSW) ash containing heavy metals. The cyclone furnace produced a
vitrified MSW ash which was below EPA leachability limits for all 8
RCRA metals. The successful treatment of MSW ash suggested that the
cyclone vitrification technology would be applicable to high
inorganic content hazardous wastes and contaminated soils that also
contain organic constituents. These types of materials exist at many
Superfund sites, as well as sites where petrochemical and chemical
sludges have been disposed. Our approach for establishing the
suitability of the cyclone vitrification technology relies on the
premise that for acceptable performance in treating contaminated
soils containing organic and heavy metals constituents, the cyclone
furnace must melt the soil matrix while producing a non-leachable
slag and must achieve the destruction and removal efficiencies (DREs,
currently 99.99%) for organic contaminants normally required for RCRA
hazardous waste incinerators. The high temperature (>2,500 to
3,OOOoF), turbulence, and residence time in the cyclone and main
furnace are expected to result in high organics destruction and
removal efficiencies (DREs).
Process Description
The Babcock & Wilcox four to six million Btu/h cyclone furnace
located in Alliance, Ohio, was used to perform all pilot-scale
vitrification tests. The furnace is water-cooled and simulates the
geometry of B&W's single cyclone, front-wall fired cyclone coal-fired
119
-------
boilers.' This cyclone facility has been proven to simulate typical
full-scale cyclone units in regard to furnace/convection gas
temperature profiles and residence times, NOX levels, cyclone
slagging potential, ash retention in the slag, unburned carbon and
flyash particle size.
The pilot cyclone furnace, shown in Figure 1, is fired by a
single, scaled-down version of a commercial coal combustion cyclone
furnace. The furnace geometry is a horizontal cylinder (barrel). A
summary of the process is illustrated in Figure 2. For the present
application, natural gas and preheated primary combustion air (820«F)
enter tangentially into the cyclone burner. In dry soil processing,
preheated secondary air (820QF), the soil matrix, and natural gas
enter tangentially along the cyclone furnace barrel. For wet soil
processing, an atomizer is used to spray the soil paste directly into
the furnace. The soil is captured and melted and organics are
destroyed in the gas phase or in the molten slag layer formed and
retained on the furnace barrel wall by centrifugal action. The soil
melts, exits the cyclone furnace from the tap at the cyclone throat,
and is dropped into a water-filled slag tank where it solidifies. A
small quantity of soil also exits as flyash with the flue gas from
the furnace and is collected in a baghouse. In principle, this
flyash could be recycled to the furnace as indicated in Figure 2 to
increase the capture of metals and to minimize the volume of the
potentially hazardous waste stream.
Particulate control is achieved by way of a baghouse. To
maximize the capture of metals, a heat exchanger is used to cool the
stack gases to approximately 2000F before entering the baghouse.
Although the cyclone facility is equipped with an acid gas scrubber,
it was not used for these tests because acid gas generation (e.g.,
HC1) from the vitrification of the SSM was expected to be low.
Applicable Wastes and Soils and Possible Technology Configurations
An advantage of vitrification over other thermal destruction
processes is that in addition to the destruction of organic
constituents, the resulting vitrified product captures and does not
leach heavy metals or radionuclides. The cyclone vitrification
technology would be applicable to high inorganic content hazardous
wastes, sludges and contaminated soils that contain heavy metals and
organic constituents. The wastes may be in the form of solids, a
soil slurry (wet soil) or liquids. To be treated in the cyclone
furnace, the ash or solid matrix must melt and flow at cyclone
furnace temperatures (2400 to 3000QF). Because of the technology's
ability to capture heavy metals in the slag and render these non-
leachable, an important application of the technology is contaminated
soils which contain non-volatile radionuclides (e.g., strontium,
transuranics).
The cyclone furnace can be operated with gas, oil or coal as the
supplemental fuel. The waste may also supply a significant portion
of the required heat input. Additional air pollution control
devices, such as NOx reduction technologies, can be applied as
120
-------
STACK PARTICULATE
SAMPLING LOCATION
CONTINUOUS EMISSIONS
MONITOR (CEM)
SAMPLING LOCATION
SSM FEED
SYSTEM
SSM
SAMPLING
LOCATION
SLAG AND
QUENCH
WATER
SAMPLING
LOCATION
ID FAN
SCRUBBER
(NOT IN USE)
FURNACE
STACK
SLAKER
(NOT IN USE)
COMBUSTION
AIR
NATURAL GAS
[INJECTORS
NATURAL
GAS
SOIL
INJECTOR
INSIDE FURNACE
SLAG
TRAP
\CYCl
SLAG ^CYCLONE
SPOUT BARREL
SLAG
QUENCHING
TANK
FIGURE l. The pilot cyclone test facility at the fi&bcock & wilcox Research and Development
Division. The insert of the furnace shows the wet soil feed configuration.
121
-------
Cyclone Vitrification Process
STACK
EMISSION
CONTROL
DEVICE
FIGURE 2.
S^^S^^^l^tS1tS"firn2: J
possible, but was not demonstrated during this p?Sjfct
devices
metals capture is
-------
needed. An acid gas scrubber would be required, for example, when
chlorinated wastes are treated.
Description of the B&W SITE Emerging Technologies Project
The EPA 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. This
project was sponsored under the SITE Emerging Technologies Program.
The goal of the SITE Emerging Technologies project, is to
perform a pilot-scale test of the Babcock & Wilcox 6 million Btu/h
cyclone furnace for vitrification of an EPA-supplied synthetic soil
matrix (SSM) spiked with three heavy metals (lead, cadmium and
chromium).
This paper will present the results of both the Phase I (1990-
1991) and Phase II (1991-1992) Emerging Technologies efforts. Both
Phase I and II used an EPA synthetic soil matrix spiked with lead,
cadmium and chromium. The most important goal for both Phase I and
II was to produce a vitrified soil that passes the Toxicity
Characteristic Leaching Procedure (TCLP) limits for lead, cadmium and
chromium. Secondary goals were the measurement of volume reduction
after treatment and heavy metals mass balance. The most significant
difference between the Phase I and II is the use of dry and wet soil
feed system, respectively. The wet soil feed system was used for the
SITE Demonstration, and thus this paper emphasizes the results for
this final system configuration.
Measurement of organics destruction efficiencies, thought to be
less of a technical challenge compared with metals capture, was
reserved for a SITE Demonstration performed in November 1991.
The SITE Demonstration
A SITE demonstration was performed on the pilot cyclone furnace
in November of 1991. An EPA-supplied synthetic soil matrix spiked
with heavy metals (cadmium, chromium and lead), organics (anthracene
and dimethyl phthalate), and simulated radionuclides (cold strontium,
bismuth, and zirconium) was used.
The demonstration was designed to test the performance of the
cyclone furnace in (1) producing a non-leachable slag for metals and
simulated radionuclides; (2) destruction and removal efficiencies for
the organics, (3) producing a greater than 10 to 1 ratio of slag to
flyash; (4) capturing at least 60 percent of the least volatile
metals; and (5) reducing the volume of the treated waste by at least
25%. Results from the demonstration are expected to be published by
EPA in fall of 1992, but preliminary results are summarized here.
MATERIALS AND METHODS
123
-------
Typical Run Conditions
Typical run conditions for the Phase I and Phase II tests are
given in Table I, below. The SITE Demonstration was run under
conditions similar to those of Phase II.
Table I. Typical Cyclone Furnace Tests Conditions.
Condition
Typical Range of Values
Heat Input (natural gas fuel)
SSM Feed Rate
Excess Oxygen
1° and 2° Air Temperature
Total Air Split-Phase I
Primary Air
Secondary Air
Feed Air
Total Air Split-Phase II
Primary Air
Secondary Air
Soil Atomizer Air
Slag Temperature
Cyclone Furnace Gas Temperature
Flue Gas Exit Temperature
Baghouse Temperature
5 Million Btu/h
50 to 300 Ib/h
1.0%
8300F
25%
72%
3%
not used
96.5%
3.5%
2370-24600F
2800-3000QF
2100-2200QF
200°F
RESULTS: SITE DEMONSTRATION VENDOR'S CLAIMS
The effectiveness of the B&W Cyclone Furnace Vitrification
Technology at _ destroying organics and immobilizing heavy metals and
simulated radionuclides in a non-leachable slag was evaluated during
the SITE Demonstration. To perform this evaluation, the following
critical and non-critical Vendor's Claims were developed by Babcock &
demonstration '^ ^ ^ U'S* *™' *" 6Valuation in the
These claims are compared with performance data for the cyclone
vitrification technology below.
124
-------
Parameter
TCLP
Slag to Flyash Ratio
Non-Volatile Metals
Capture (Cr) in the
Slag
Volume Reduction
DREs
CO, THC, Particulates
Claim
Critical Claims
Produce a vitrified slag that does not
exceed Toxicity Characteristic Leaching
Procedure (TCLP) regulatory levels for
cadmium (i.e., <1 mg/L), lead (<5
mg/L), and chromium (<5 mg/L).
Achieve at least a 10 to 1 ratio (dry
weight basis) of slag to flyash.
Capture at least 60% (by weight) of the
non-volatile metal chromium from the
dry, untreated SSM in the vitrified
slag.
Achieve at least a 25 percent volume
reduction in solids when comparing
product solid to untreated SSM.
Achieve a 99.99% destruction and
removal efficiencies DREs for each
organic contaminant spike (anthracene
and dime thylphthal ate ) .
Comply with emission limits for CO,
total hydrocarbons ( THC ) , and
particulates from the stack as
stipulated by 40 CFR 264 (i.e., CO of
<100 ppm, THC of <20 ppm, and
particulates of <0.08 gr/dscf at 7%
oxygen ) .
Non-Critical Claims
ANS 16.1 Simulated
Radionuc 1 ide
Leachability
Non-Volatile
Radionuclide Capture
in the Slag
Produce a slag that immobilizes (passes
leaching standards ) radionuclides as
measured by the American Nuclear
Society test (ANS) 16.1 (i.e., ANS 16.1
calculated leachability index (LI) >6).
Capture at least 60% (by weight) of the
non-volatile metals strontium and
zirconium in the vitrified slag.
COMPARISON OF PERFORMANCE RESULTS FROM THE TWO SITE EMERGING
TECHNOLOGY PROJECTS WITH THE VENDORS CLAIMS
Synthetic Soil Matrix and Feed Conditions
125
-------
Two Superfund Innovative Technology Evaluation (SITE) Emerging
Technology projects were conducted prior to the SITE Demonstration.
These two projects, Phase I and Phase II, were conducted to establish
the feasibility of the cyclone vitrification process for dry soil
(Phase I) and wet soil (Phase II) treatment. In each project,
measurements were made to evaluate TCLP leachabilities, volume
reduction, and materials and heavy metals mass balances.
A synthetic soil matrix formulated by EPA was used for all
cyclone testing. Both clean and spiked SSM were obtained from the
EPA Risk Reduction Engineering Laboratory (RREL) Releases Control
Branch in Edison, NJ. SSM, used by EPA for treatment technology
evaluations, has been well-characterized in previous studies [ 1 ].
Clean soil was used for furnace conditions optimization. The spiked
SSM used in the Emerging Technologies projects contained 7,000 ppm
(0.7%) lead, 1,000 ppm (0.1%) cadmium, and 1,500 ppm (0.15%)
chromium.
In Phase I, dry SSM was processed at feed rates of 50 to 150
Ib/hr. In Phase II, wet SSM was processed at feed rates of 100 to
300 Ib/hr (dry basis). Approximately 11 tons of spiked and unspiked
SSM were processed during each of the two project Phases.
Performance Results
A comparison of Phase I and II results against the Vendor's
Claims developed for the Demonstration is presented below. Not all
of the Demonstration claims were tested during these projects (e.g.,
DRE, ANS 16.1 were omitted). All claims tested were met or exceeded
during these Emerging Technology projects (the Claims were finalized
on the basis of these results).
Parameter
TCLP-Cadmium
TCLP-Lead
TCLP-Chromium
Slag to Flyash
Ratio
Non-Volatile Metal
(Cr) Capture in the
Slag
Volume Reduction
Performance
Criterion
in Vendor's
Claim
1.0 mg/L
5.0 mg/L
5.0 mg/L
10:1
60%
25%
Performanc
e Measured
in
Phase I*
0.13 mg/L
0.20 mg/L
0.11 mg/L
14.6:1
80-95%
35%
Performan
ce
Measured
in Phase
II*
0.07 mg/L
0.20 mg/L
0.04 mg/L
34:1
78-95%
25%
*Average results where several measurements were made.
126
-------
COMPARISON OF PERFORMANCE RESULTS FROM THE SITE DEMONSTRATION WJ2W
THE VENDORS CLAIMS
Synthetic Soil Matrix and Feed Conditions
On the basis of the Phase I and II Emerging Technology projects,
Babcock & Wilcox was asked to perform a SITE Demonstration. For the
Demonstration, a wet SSM was used. Demonstration goals included the
vendor's claims given above.
The SSM used in the SITE Demonstration contained 7,000 ppm lead,
1,000 ppm cadmium, and 4,500 ppm chromium; 6,500 ppm anthracene;
8,000 ppm dimethylphthalate; and the three simulated radionuclides:
4,500 ppm bismuth, 4,500 ppm strontium, and 4,500 ppm zirconium. The
rationale for B&W's choice of radionuclide surrogates is as follows:
Bismuth was used as a surrogate for volatile radionuclides important
at DOE/DOD sites such as cesium (cold cesium was originally proposed
but found to be excessively expensive). Cold strontium was used as a
surrogate for radioactive strontium (the cold version of the
radionuclide is the best possible surrogate). Zirconium was
considered an excellent surrogate for radioactive thorium and uranium
from the standpoint of both volatility and chemical behavior (all are
oxophillic and tend to be in the +4 oxidation state).
A total of 3 tons of SSM were processed during the Demonstration
at a feed rate of 170 Ib/hr.
Performance Results
A comparison of the Demonstration results against the Vendor's
Claims developed for the Demonstration is presented below. All
claims tested were exceeded during the Demonstration»
SUMMARY
The Babcock & Wilcox 6 million Btu/hr pilot cyclone furnace met
or exceeded all critical and non-critical Vendor's Claims. Because
these performance results were measured on a pilot cyclone furnace
configured as a utility boiler, and by no means optimized for soil
vitrification, a unit designed for dedicated soil vitrification may
improve process performance and throughput.
REFERENCE
1. P. Esposito, J. Hessling, B. Locke, M. Taylor, M. Szabo, R.
Trumau, C. Rogers, R. Traver, and E. Earth, "Results of
Treatment Evaluations of a Contaminated Synthetic Soil," JAPCA,
39: 294 (1989).
127
-------
Parameter
TCLP-Cadmium
TCLP-Lead
TCLP-Chromium
Slag to Flyash
Ratio
Non-Volatile Metal
(Cr) Capture in the
Slag
Non-Volatile Metal
(Sr) Capture in the
Slag**
Non-Volatile Metal
(Zr) Capture in the
Slag**
Volume Reduction
DRE-Anthracene
DRE-
Dimethylphthalate
CO
THC
Particulates
ANS 16.1
Leachability-
Bismuth**
ANS 16.1
Leachability-
Strontium**
ANS 16.1
Leachability-
Zirconium**
Performance
Criterion in
Vendor's Claim
1.0 mg/L
5.0 mg/L
5.0 mg/L
10:1
60%
60%
60%
25%
99.99%
99.99%
<100 ppm
<20 ppm
0.08 gr/dscf***
LI > 6
LI > 6
LI > 6
Performance
Measured
in Demonstration*
0.12 mg/L
0.29 mg/L
0.30 mg/L
15.6:1
76%
88%
96%
28.1%
>99.996%
>99.998%
4.8-54.1 ppm
<5.9-18.2 ppm
0.001 gr/dscf***
LI = 13.4
LI = 13.1
LI = 8.7
*Average results where several measurements were made.
**Non-critical parameter.
***Corrected to 7% oxygen.
128
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THE ECO LOGIC PROCESS
D.J. HALLETT, Ph.D., President
K.R. CAMPBELL, P.Eng., Vice President
ELI ECO LOGIC INTERNATIONAL INC.
143 Dennis Street
Rockwood, Ontario
Canada
NOB 2KO
2395 Huron Parkway
Ann Arbor, MI
U.S.A.
48104
129
-------
THE ECO LOGIC PROCESS
Douglas Hallett, Ph.D.
Kelvin Campbell, P.Eng.
The ECO LOGIC Process is a high-efficiency destruction alternative to incineration
which is particularly suitable for hazardous wastes with a substantial water content. The
process is based on the gas-phase thermo-chemical reaction of hydrogen with organic and
chlorinated organic compounds. At 850°C or higher, hydrogen combines with organic
compounds in a very efficient reaction known as reduction to form smaller, lighter
hydrocarbons, primarily methane. For chlorinated organic compounds, such as PCBs, the
reduction products include methane and hydrogen chloride. This reaction is enhanced by the
presence of water, which can act as a reducing agent and a hydrogen source. Bench-scale,
lab-scale, and pilot-scale testing has shown that destruction removal efficiencies (DREs) of
99.9999% can be achieved.
The main features of the patented ECO LOGIC Process include:
1. High destruction efficiency
2. No possibility of dioxin or furan emissions
3. Continuous monitoring and process control suitability
4. Suitability for aqueous wastes
5. Mobility
6. Reasonable cost
The high efficiency of the process has been demonstrated with PCBs, PAHs,
chlorobenzenes, and organochlorine pesticides. During the demonstration testing of the pilot-
scale system at Hamilton Harbour in the summer of 1991, coal-tar PAHs at levels of 30% (dry
basis) in the harbour sediment were effectively eliminated. DREs of 99.99999% were
calculated (see Table 1), based on the total organic input and the PAHs analysed in the stack
emission. During one test, the liquid waste input was spiked with 500 ppm PCBs, with the
result that there were no detectable levels of PCB in the air emission, the processed solids, or
the liquid effluents. Based on detection limits for the stack sampling trains, a PCB DRE of at
least 99.9999% was achieved.
130
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HAMILTON HARBOUR SEDIMENT
ANALYTICAL RESULTS SUMMARY
3% ORGANIC COAL TAR
Run
PI
P2
P3
P3
Target
Analyses
PAHs
PAHs
PAHs
PCBs
Waste
Influent
Cone.
(ppm)
21,000
30,000
30,000
500
Decant
Water
Cone.
(ppb)
483
680
423
ND
Grit
Cone.
(ppm)
1.67
7.76
0.37
ND
Sludge
Cone.
(ppm)
32.8
56.1
4.3
ND
Stack
Gas
Cone.
Oig/m3)
0.27
0.23
0.14
ND
Destructk
Removal
Efficienc
(%)
99.99999
99.99999
99.99999
99.9999
* DRE = (Total Input - Stack Emissions) / (Total Input)
-------
One of the distinct differences between the ECO LOGIC Process and incineration
processes is that there is no possibility of dioxin or furan formation with the reduction process.
These compounds can .be formed by the incomplete oxidation of PCBs, but in an actively
reducing atmosphere with an abundance of free hydrogen and no free oxygen, the possibility
of their formation is eliminated.
The use of hydrogen as an active reducing agent in the process also creates a product
gas of low molecular weight without the formation of heavier hydrocarbons common to
pyrolysis processes. This product gas is suitable for continuous monitoring, and ECO LOGIC
has included in the process control design a very sophisticated on-line mass spectrometer which
can monitor organic compounds continuously in the parts per billion range. This allows the
operator and the process control system to effectively monitor destruction efficiency by
selectively analyzing for trace concentrations of known breakdown products of the hazardous
waste.
Another feature of the ECO LOGIC Process is its ability to process aqueous wastes.
Water does not inhibit, but actually enhances the reduction process, and also provides a source
of hydrogen through the water shift reaction with methane. After the destruction of the organic
contaminants in the reduction reactor, the water and the HC1 produced are removed in a
scrubber and the clean, dry product gas can be recirculated back to the reactor or used as
supplementary fuel in the propane boiler. At Hamilton Harbour, approximately 97% of the
product gas was recirculated to take advantage of the hydrogen content, and about 3% was sent
to the boiler. The boiler produced steam which was used to pre-heat the waste prior to
injection into the reactor.
Other features of the ECO LOGIC Process are the high degree of mobility and the
reasonable operating cost. The process is mounted on two standard drop-deck highway trailers
and is easily set up and taken down. The relatively small size and capital cost help keep the
operating cost per tonne fairly low. The price for processing high moisture-content matrices
such as contaminated soils, sludges, and sediments is projected to start at $400 per tonne for
the first 100-tonne/day commercial unit. High-strength PCB liquids can be processed at the
same time as environmental wastes with only a limited price increase.
132
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WASTES SUITABLE FOR DESTRUi
CHEMICALS:
Non-halogenated / halogenated biphenyls
Non-halogenated / halogenated benzenes
Non-halogenated / halogenated phenols
Non-halogenated / halogenated cycloalkanes
Non-halogenated / halogenated alkanes
Non-halogenated / halogenated dioxins
Non-halogenated / halogenated dibenzofurans
Polyaromatic hydrocarbons
* Note: Halogenated means: Chlorinated
Brominated
Fluorinated
TYPICAL WASTES;
PCBs
Pulp mill wastes
Chlorinated solvent waste
Contaminated coal tars
Solvent still bottoms
Chlorophenols / Wood treatment waste
Pesticide wastes
Landfill leachates
Lagoon bottoms
133
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The ECO LOGIC Process has been accepted into the US EPA Superfund Innovative
Technology Evaluation (SITE) Program, following the successful demonstration at Hamilton
Harbour last summer. A demonstration program in the autumn of 1992 at a landfill site in
Michigan will be funded by ECO LOGIC, Environment Canada, and Environment Ontario,
and the evaluation will be performed by the US EPA. The site is contaminated by a dense
oil containing approximately 40% PCBs. This oil will be processed along with contaminated
groundwater and contaminated soil, in separate streams, as in Table 2.
ECO LOGIC began operation in 1986 when Dr. Hallett proceeded to patent the gas
phase thermo-chemical reduction process for the destruction of high hazardous organic
chemicals. Research has led to subsequent inventions in on-line continuous emission/process
monitoring using chemical ionization mass spectrometry, and computerized process control
systems and software for hazardous waste. The company's mission is to manufacture, supply,
operate, and service high technology for the destruction or control of hazardous chemicals and
the remediation of hazardous waste landfills, lagoons, soils, and sediments.
ECO LOGIC will enter the market to supply hazardous waste destruction services itself
with its own machines, and to license and sell equipment to companies that already supply
services, or to licence and sell to large chemical producers or users where ownership is
economically advantageous. The service market is the initial focus in order to demonstrate the
machine and obtain approvals in jurisdictions where units will be licensed and sold when the
technology has buyer (versus user) acceptance.
We would encourage interested parties with organic hazardous waste problems to contact
our offices in Rockwood and Ann Arbor.
This offers potential clients the opportunity to obtain direct information on the
application of this technology to the resolution of their hazardous waste problems.
Wayland R. Swain, Ph.D.
Vice President
U.S. Operations
ELI Eco Logic International Inc.
2395 Huron Parkway
Ann Arbor, Michigan 48104
313-973-2780
Jim Nash, B.A.
Manager
Sales and Business Development
ELI Eco Logic International Inc.
143 Dennis Street
Rockwood, ON Canada NOB 2KO
519-856-9591
134
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During September and October, 1992, The U.S. Environmental Protection Agency, in
co-operation with the City of Bay City, Environment Canada, and the Ontario Ministry of the
Environment will sponsor a demonstration and evaluation of the EU Eco Logic Process at Bay
City's Middleground Landfill. This demonstration will occur under the auspices of the U.S.
EPA's Superfund Innovative Technology Evaluation (SITE) Program.
HAZARDOUS WASTE DESTRUCTION DEMONSTRATION
BAY CITY, MICHIGAN
OILY WATER (7 T/DAY)
5 kg/min contaminated water (TCE)
.05 kg/min PCB oil (40% PCBs)
(feed concentration of4000ppm PCBs)
1.
•
•
2. SOIL (15 T/DAY)
• 10 kg/min contaminated soil (1000 ppm PCBs)
• 1 kg/min contaminated water (TCE)
3. OIL/WATER (3 T/DAY)
• 1 kg/min PCB oil (40% PCBs)
• 1 kg/min contaminated water (TCE)
(feed concentration 20% PCBs)
4. 72-HOUR RUN OF 1 OR MORE OF 3 CASES ABOVE
135
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SM
BioGenesis Soil Washing Process
Technology Summary
GENERAL D^CRIPTION
° The BioGenesis soil remediation technology is capable of extracting volatile and
non-volatile oils including crude oil, chlorinated hydrocarbons, pesticides, and other
organics from most types of soil and clay. A single "Soil Remediation Unit," using
a complex bioremediating surfactant and water, washes 25 to 30 tons of soil an
hour, depending on the pollutant, contamination level, and soil type.
DEVELOPMENT STATUS
° Being introduced to the United States as part of the EPA's Superfund Innovative
Technology Evaluation (SITE) Program.
n First commercial use hi October, 1992, removing crude oil from contaminated soil
at mid-west refineries; work in progress to complete cleaning of over 5,000 cubic
yards by early 1993.
SPECIAL FEATURES
° Wastes are reduced to recyclable oil, treatable water, and active soil suitable for
onsite backfill.
° Treats both volatile and non-volatile oils.
° Complex surfactant used is safe, 100% rapidly biodegradable, and has low toxicity.
n Processing rate is 25-35 tons per hour for one washer unit.
n Organics do not combine with the surfactant.
n Surfactant enhances the biodegradation of residual contamination.
° Potentially effective on broad range of chlorinated hydrocarbons, pesticides, PCBs,
and other organic pollutants.
° Treats soils with high clay content and heavily weathered soils.
° No air pollution except that connected with excavation.
n No toxic by-products produced besides the contaminant removed.
PLANNING FACTORS
° Variables. Contaminant, amount of contamination, soil type, job size, and cleanup
target.
° Effectiveness. Heavy hydrocarbons, one wash-95%, two washes-99%+; light
hydrocarbons, one wash-97 to 99%. Residuals polished through biodegradation.
° Cost $40-180 per ton depending on the variables; average range $60-100 per ton.
EQUIPMENT & MANPOWER
n Equipment.
Earth moving equipment.
Truck mounted washer unit, 20 cubic yards capacity.
Hydrocyclones, centrifuge, and flotation units for the separation of fines.
Gravity separators and coalescing filters for oil water separation.
n Manpower. The mobile system is operated by five personnel: a system supervisor, a
test director, two operators, and a materials handler.
__ BioGenesis Enterprises, Inc.
CHICAGO, ILLINOIS' TEL (708) 827-0024 • WASHINGTON, DC' TEL(703)250-3442
136
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FULL SCALE FIELD RESULTS
3% CRUDE OIL CONTAMINATION, MINNESOTA REFINERY,
ONE WASH, METHOD 9073 TESTING, mg/fcg
- - Soil Fraction
Large Particles > 40 Mesh
Fines < 40 Mesh
TRPH Level
Before
30,800
30,800
TKPH Level
After
1,620
4,520
Extraction
Percent, One Wash,
95%
85%
BIODEGRADATIONOF RESIDUAL CONTAMINATION AFTER
, ONE WASH, METHOD 9073 TESTING, mg/kg
/, f~' ^ s
' Days After Washing
Zero
Seven
Fourteen
TRPH, Fines
< 40 Mesh
4,550
2,200
1,300
* N Cumulative
Effectiveness, Fines
85%
93%
96%
s BTEX REMOVAL EFFECTIVENESS, FINES < A
ONE WASH, METHOD 8920 TESTING, m
Contaminant
Benzene
Toluene
Ethylbenzene
Xylenes
Total BTEX
Unwashed
Soil
<0.24
<0.25
1.2
4.3
5.99
Fines
< 40 Mesh
<- ?"•
< 0.024
0.034
< 0.016
0.073
0.147
K) MESH,
g/kg
Removal
Effectiveness,
Fines, One Wash
90.0%
86.4%
98.7%
98.3%
97.6%
SIEVE ANALYSIS, UNWASHED SOIL AND FINES
Percent Passing •»-»••
Unwashed Soil
Fines
10 Mesh
72
100
40 Mesh
18
94
120 Mesh
4
33
200 Mesh
3
11
CONTACT POINT
o Charles Wilde, TEL: (703) 250-3442, FAX: (703) 250-3559
137
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BioGenesis"" Soil Washing Process
Contaminated Soli
Vacuum Oil Skimmer
Hood\ / System
'\ /
Treated Soli
J.
Atmosphere
Soil Washer
Unit
BioGenesis
Cleaner
Holding Tank 1
' Effluent from ClL
Washer Unit
Strainer
Water Calmer
^ Activated Carbon
Filters
Solids
Oil Skimmer
Holding Tank 2
Solids
Baffle
Separator
Recycle to'" •
Washer Unit
Holding Tank 3
Clean water to Disposal
138
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8M
BioGenesis Soil Washing Process
8M
The BioGenesis process is designed to treat
soils and other types of solids contaminated
with organic compounds, including volatile
and non-volatile hydrocarbons. The treat-
ment is a two-stage process; first, extract
contaminants from soil using water and Bio-
Genesis cleaner; second, accelerate the
biodegradation of residual soil contamination
and contaminant-rich wastewater.
The major components of the treatment
system include the following:
° Soil washing unit. This is the principal
component of the treatment system. The
unit holds 20 cubic yards, about 25 tons.
The washer has a perforated bottom to
introduce air for mixing and to drain
wastewater. A poly-canvas hood with
vacuum extraction covers the top of the
wash unit to collect any organic compounds
volatilized during treatment.
Oil skimmers. Oil is skimmed from the
surface of the soil and water mixture. Oil
can be skimmed two ways. A manual
method requires workers to skim oil from
the top of the water to the Baffle Separator.
A mechanical method uses rising water to
push the oil/water into a system that runs
through an elastometer belt. Oil clings to
the belt while water flows through.
Q Strainers. Strainers are located at the ends
of the oil skimmer troughs on the wash
unit. The strainers prevent floating debris
from damaging the transfer pump.
a Two 7.5-horsepower(hp) transfer pumps.
These pumps are used to transfer waste-
water from the wash unit to the baffle
separator.
° Baffle Separator. This unit is used as a
primary separator to separate oil from the
waste water through a series of baffles.
a Gravity Separator and Oil Coalesces
These units are used as a secondary sepa-
rators to separate the oil phase from the
wastewater. The unit is equipped with an
infrared (IR) detector. The detector con-
trols a diversion valve that depending on oil
concentration in the water, either returns
the water to the influent line and to the
gravity separator or to the bioreactor.
a Bioreactor. The bioreactor is a cylindrical
shaped tank with a holding capacity of ap-
proximately 5,000 gallons. At the end of
operations, wastewater from the oil/water
separators is transferred to the bioreactor.
A specially formulated BioGenesis8"
solution is added to the bioreactor to stimu-
late biodegradation of residual contamina-
tion in the wastewater. Within the
bioreactor, water is mixed by pumping it
through a spray aerator fitted above the
liquid phase. The bioreactor is covered with
an activated charcoal filter to minimize
losses due to volatilization.
One 48-foot flat bed trailer. This trailer
houses a 200-ampere (amp), 480 VAC,
139
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cooled air compressors; a vacuum source;
and a gravity separator and oil coalescer.
SM
The BioGenesis process begins by introduc-
ing approximately 1,000 gallons of water into
the wash unit. Next, contaminated soil is
added to the wash unit, normally with a front-
end loader. The wash unit is capable of
treating 20 cubic yards per batch. If volatile
organic compounds (VOC) are present, the
wash unit is covered with a retractable canvas
cover. A positive air flow is drawn through
the back of the wash unit, creating a negative
pressure within the unit. Air flow is directed
to strip away any VOCs. Volatile emissions, if
any, are passed through a granular activated
carbon filter before being vented to ambient
air.
EM
Water and BioGenesis cleaner are premixed
in a 4,800-gallon holding tank (Holding Tank
1) and pumped into the wash unit. A typical
wash requires approximately 2,500gallons of
water and 8 gallons of BioGenesis cleaner.
The resulting slurry is agitated by a series of
aerators in the bottom of the wash unit. After
the soil slurry is mixed for a period of time, air
is turned off, and water is added to raise the
fluid level to allow floating oil product to flow
out of the unit via ports located 8 inches from
the top of the unit into a holding tank
(Holding Tank 2). After the floating product
is removed, the soil slurry is agitated again for
a period determined by the operator. The
fluid level is again raised to allow for oil/water
to be removed through the ports. Soil settles
to the bottom of the wash unit.
Wash water from the bottom of the wash unit
and oil/water exiting through the ports are
pumped to Holding Tank 2 which is equipped
with an oil skimmer. After the water has
drained from the treated soil, the operator
inverts one end of the wash unit, dumping the
soil onto the ground whence it is moved by
front loader to a clean soil holding area
pending test and final clearance.
In Holding Tank 2, the oily material removed
by the skimmer is pumped to 55-gallon drums.
Material not removed by skimming is pumped
to a baffle separator. The use of the baffle
separator is optional based on the operator's
discretion. Any oily material recovered from
140
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the baffle separator is pumped to 55-gallon
drums. Water from the baffle separator is
then directed to a 4,800-gallon holding tank
(Holding Tank 3) for storage prior to reuse in
the wash unit. Approximately 15 percent of
the wash water is retained in the soil;
SM
therefore, make-up water and BioGenesis
cleaner must be added to the recycled water as
needed. Any make-up water for the next
batch of soil is supplied from Holding Tank 1.
SM
Soil washing, the BioGenesis " method,
excavates soil with earth-moving equipment,
separates contaminants in a washing process,
and returns the soil to the excavated area. It
positively removes the contaminant, works on-
site, and produces no toxic byproducts except
the contaminant removed.
Historically, difficulties with washing
chemicals, equipment efficiency, and inability
to treat soils with more than 30% clay have
impeded implementation of soil washing.
BioGenesis solves these problems with its
complex surfactant mixtures and efficient
washing equipment. BioGenesis8** soil
washing is competitive with other technologies
in almost all situations. The determining
factors of price are soil type, contaminant
type, dirtiness, job size, and cleanup target.
Once all runs are complete, the water in
Holding Tank 3 is processed through the
oil/water separation unit, which includes a
ring chamber gravity oil/water separator and
an oil coalescing filter. Water from the coales-
cer is monitored by an infrared (IR) detector
and is directed to a bioreactorif the oil
concentration is below 10 ppm. If the oil
concentration is above 10 ppm, the water is
recycled through the gravity separator and
coalescer until the oil concentration is below
10 ppm. Oily material from the gravity
separator and the coalescer is pumped to 55-
gallon drums. Sediments from the wash unit,
Holding Tank 2, the baffle separator,and the
bioreactbr are stored in storage bins and
covered with plastic sheets. Samples from the
sediment storage and treated soil storage are
collected over a period of tune and analyzed
for chemical composition.
141
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Steam Enhanced Recovery
(SERF)
William R. Van Sickle
(310)536-6547
Process
ABSTRACT
In-situ steam enhanced recovery, utilizes formation tailored injected
low pressure steam to establish temperature and pressure gradients
to improve the migration of hydrocarbons through the soil. Vapor,
free-liquid hydrocarbons and condensate are removed using specially
designed vapor extraction wells. Steam enhances removal of
hydrocarbons and allows extraction of heavier petroleum products by
elevating the vapor pressure and reducing the viscosity, thereby
inducing greater hydrocarbon mobility. The time required to remove
hydrocarbon vapors and liquids is reduced and removal efficiency is
increased, with consequent reductions in project cost. Vapors and
liquids are treated at the surface using thermal oxidation and waste
water treatment respectively.
INTRODUCTION
Steam injection remediation was a diversification of the Enhanced Oil
Recovery (EOR) process in use by the petroleum industry since the
1950's (Hong 1989). Brought to the environmental industry by the
Dutch firm of Heidemij Reststoffendiensten, laboratory studies,
research and pilot projects in the United States (Hunt, et al,
1988/1989) followed. As a result of available data and site
requirements, the Steam Enhanced Remediation Process was selected
for use at a large industrial site in Southern California (Dablow,
1991). This paper addresses unique aspects of the project as well as
provided an update of the current status.
PROJECT SITE
The Rainbow project resulted from the inadvertent puncture of a
diesel fueling manifold during construction activities. Undiscovered
1240 Rosecrans Ave., P.O. Box 10011, Manhattan Beach, CA 90266-8511 • (800) 262-HESI • FAX (310) 536-5434
142
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for about two years, estimates of 20,000 - 100,000+ gallons of fuel
leached down to the groundwater and migrated offsite to the north
and west. Sediments of the contaminated formation consists of
several feet of fill material, partially cemented sands, and clayey silts
with lenses of fine to medium sand. The fuel leak formed a column
approximately 100 feet in diameter that migrated downward,
spreading laterally as less permeable mud's were encountered. Upon
penetrating the mud's, downward migration continued, stopping
where ground water was encountered.
The plume of greater than two acres was located primarily under a
trash recycling and transfer station. Expansion requirements
required an accelerated remediation, as did the need to prevent
further offsite migration. A high volume of traffic (500 - 700 trucks
per day/6 days, two shifts) required an in-situ process that .did not
impede operations or interfere with traffic. Construction was
completed and all operating permits received to commence
remediation in April 1992.
SYSTEM DESIGN AND DEVELOPMENT
System design was based upon soil characteristics, estimated soil
volume, well spacing and quantity, and temperature/pressures
necessary for vaporization. The design was selected to accelerate the
remediation of the large area impacted. Extensive sampling and
characterization of the site were combined with bench scale testing
and modeling to determine injection and extraction well influence
radius and well placement. 37 injection wells were placed to totally
surround the plume to stop offsite migration and to move
contaminant towards the center of the plume. Oversized boilers
were specified to provide the capacity for rapid heating of the entire
site. 39 extraction wells were designed and installed for the dual
purpose for vapor and product/condensate recovery. It was
anticipated that 90% of the contaminant recovered would be liquid
phase which would be treated by an oily water separator, micron
filtration system and polished by activated carbon. Vapor treatment
utilized a packed bed thermal oxidizer. 80% of the injection wells,
extraction wells and system piping were placed in trenches and
covered. All work on the trash transfer station site was
accomplished on the third shift Monday through Saturday or on
Sundays.
143
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PROJECT STATUS
Remediation is in full swing. Significant delays were encountered as
a result of under estimations of the permitting processes and the
need to throttle down key injection wells while an alternative for the
underground fueling system was designed, permitted and installed.
At this point only small traces liquid phase hydrocarbons have been
recovered. Four thousand four hundred gallons of free product were
recovered and fourteen thousand gallons have been recovered by the
vapor extraction system in five months of effective system operation.
Approximately 1200 CFM of vapor are flowing into the thermal
pxidizer with Total Petroleum Hydrocarbons (TPH) gradually
increasing from 700 ppm to a current level of about 3,000 ppm. As a
result more than two thousand gallons per month are being
recovered.
CONCLUSIONS
The Steam Enhanced Recovery Process appears to be effectively
removing diesel fuel from the soil and perched aquifer. The plume
has been reduced to 20-30% of its original volume. System design
has allowed monitoring, control and manipulation of pressure and
vacuum gradients to protect underground tanks and to focus on
specific areas to be remediated. Monitoring wells have not detected
unwanted migration of hydrocarbons off site or into lower aquifers.
To date no interruption of site operation has occurred.
The use of the steam enhanced recovery process when applied to
appropriate substances, offers the following advantages over other
techniques:
- Enhances removal of volatile and semivolatile
hydrocarbons
- Effective for heavy hydrocarbons
- Not limited by soil concentrations
- Process easily monitored and verified
- In-situ process with minimal surface impact
The following disadvantages of steam enhanced recovery
process should be considered:
- Capital costs
- A cap may be necessary for remediation on sites with
high vertical permeability surface conditions
- Extensive permitting maybe required
144
-------
- Trained boiler technicians may be needed as part of the
O&M team
REFERENCES
Dablow, J.F., 1991 "Steam Injection to Enhance Removal of Diesel
Fuel" presented at HAZMACON 91, Santa Clara, California, April 15-
17, 1991.
Hong, K.C., 1989 "Recent Advances in Steamflood Technology",.
represented at the 1989 Indonesian Petroleum association
Convention.
Hunt, J.R. Sitar, N. and Udell, K.S., 1988 "Non aqueous Phase Liquid
Transport and Cleanup", Water Resources Research, volume 24.
Udell, K.S., and Stewart, L..D., 1989 "Mechanism of In Situ
Remediation of Soil and Groundwater Contamination by Combined
Steam Injection and Vacuum extraction", Paper No. 119d presented
at the Symposium on thermal Treatment of Radioactive and
Hazardous Waste at the AICHE annual meeting, San Francisco,
California, November 6, 1989.
145
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SOIL VENTING TO REMOVE DBCP FROM SUBSURFACE SOIL:
A CASE HISTORY
M.B. Bennedsen, F. Gomez, C.R. Kneiblher, J.D. Dean, J. Scott
Woodward-Clyde Consultants
ABSTRACT
Dibromochloropropane (DBCP) was widely used as a soil fumigant for the control of
nematodes during the 1970s. In 1979, the EPA restricted its use, primarily because of its
toxicity to mammals. In the early 1970s, a spill of about 3,100 gallons of DBCP occurred
at an agricultural chemicals distribution facility in the San Joaquin Valley of California.
Groundwater at the site is at a depth of about 100 feet. The vadose zone soils are alluvial,
moderately stratified, and vary from silty fine sands to coarse sands with some gravel. In the
1980s DBCP was detected in the area groundwater, and investigations in the vicinity of the
spill found DBCP throughout the soil column above the water table. Because of the depth
of the soils contamination, and the existing facilities at the surface, only in situ remedial
technologies were considered feasible. DBCP has a melting point of 6.7°C and low vapor
pressure at ambient soil temperatures. However, the decision was made to try soil venting
for removing the vapor phase component and possibly stimulating biodegradation of the
liquid phase component of the material. The system installed for the purpose has been
operating since January 1992, and at this time has removed several hundred pounds of DBCP
plus many thousands of pounds of CO2 from the area soil. The focus of this paper is to
provide additional information on the design and operation of the installed soil venting
system. The project is considered of interest to this conference because of the nature of the
contaminant, the use of an on-line G.C. to provide a continuous and current record of system
performance, relatively low costs for operations and because it does not interfere with on-
going facility operations.
146
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During the 1970s an estimated 3,100 gallons, or about 60,000 pounds, of 1,2-dibromo, 3-
chloropropane (DBCP) were accidentally released onto the ground surface during a rail tank
car unloading operation. The material is known to be toxic to mammals. The release
occurred at an agricultural chemicals distribution facility, in the Central Valley of California.
Soils in the area of the spill are alluvial, varying from silty fine sands to coarse sand with
some gravel, and some stratification. Soil samples, collected in the late 1980s from
throughout the vadose zone, contained detectable DBCP concentrations. Also, DBCP has
been detected in the area groundwater, which is at a variable depth, but generally in the range
of about 90 to 110 feet below the ground surface. Limiting or preventing further migration
of DBCP from the soil to the groundwater was clearly desirable.
Because of the depth of the soils contamination, and the physical constraints created by
existing facilities surrounding the spill site, only in situ remedial techniques were considered
applicable. In consultation with the State of California, Environmental Protection Agency,
Department of Toxic Substances Control, Alternative Technologies Division, and with the
concurrence of the California Regional Water Quality Control Board-Central Valley Region,
it was agreed that soil venting might be an appropriate technology in this instance. A short
term venting test (a few hours) demonstrated that venting could remove DBCP from the soils
at a significant rate. Based on the test results, and a proposed venting system design that
would prevent discharge of extracted DBCP to the atmosphere, the Department of Toxic
Substance Control granted a Variance From Permit Requirements, for a two-month, trial
program operation. At the conclusion of the trial program operation, and based on the results
of the operation, an Extension of the Variance From Permit Requirements was granted to
allow an additional year of operation. The venting process was considered experimental in
this application because the vapor pressure of DBCP, at ambient soil temperature, is about
1 mmHg, and near the lower limit generally considered appropriate for soil venting.
Three soil borings had been drilled in the area of the spill to assess the extent of the
contamination. The borings were located within the areas of maximum contamination as
determined by a soil gas survey. One of the borings was completed as a groundwater
monitoring well. For the short-term venting test, three vapor extraction/soil venting wells
were installed with 2-inch-diameter PVC casing and with screened intervals extending from
20 to 40 feet, 40 to 60 feet, and 60 to 80 feet, respectively, below the ground surface.
Figure 1 presents simplified stratigraphic data for the soils penetrated by these wells, and data
on contaminant concentrations in soil samples collected during the drilling of the wells.
The borings were on a line paralleling, and about 10 feet from the rail spur on which the tank
car was set when the spill occurred. The in-line separations between the wells were about
13 feet and 40 feet, respectively. The borings were advanced using dual-tube reverse-
circulation drilling techniques, and the boring diameters were about 10 inches. Because of
the toxic properties of DBCP,. the drill crew worked in Level B protective equipment — i.e.,
fully covered and with supplied air.
147
-------
To make a preliminary assessment of the applicability of soil venting at this site, and to
obtain design information in case the technique was judged applicable, the short term test,
mentioned above, was performed. The test demonstrated that it was possible to extract at
least 100 cubic feet per minute (cfm) of soil gas from each of the three wells, at an applied
well head vacuum of about one inch, mercury gage (1 in. Hg). Also, based on the soil gas
extracted during the test, it was estimated that a production VES would initially extract a gas
containing 10 to 15 parts per million, volumetric (ppmV) DBCP. This extraction rate was
considered sufficient to justify installation and operation of a production type soil venting
system. Again, it is noted that the short-term test was performed with the test crew utilizing
Level B protective equipment.
Based on the results of the short-term test, a vapor extraction system was designed and
installed at the site. The major system components, in the order of flow were: wells, valved
manifold, air/water separator drum (knockout tank), two carbon tanks in series, blower,
silencer, and discharge stack. To monitor the system performance, an on-line gas
chromatograph (GC) was included. The GC was equipped with an electron capture detector
and an automatic, programmable sampling pump and a multiport sampling valve connected
to the gas stream at the inlets to the first and second carbon canisters, the discharge from the
second canister, and to the atmosphere as a reference point for system blanks. The carbon
canisters were located upstream from the blower, where they would operate under negative
pressure relative to atmospheric. The objective was to prevent the possible release of
untreated, extracted soil gas to the atmosphere.
In November 1989 the system was initially operated. However, it operated for only about
100 hours before excessive pressure drops occurred in the flow through the carbon canisters,
and the lid of the number two canister collapsed. Investigation of the cause of failure
revealed that ammonia salts had plugged the carbon. Low ambient temperatures — about 30°
to 40°F — at the time of the operation, probably contributed to solids formation. During the
initial operation, a strong ammonia odor was noticed in the gas discharged from the system.
It is known that large quantities of ammonia based fertilizers are handled at this facility, and
it is expected that leaks or spills thereof resulted in ammonia being present in the extracted
soil gas. Because all work associated with installing the VES wells, and performing the
initial short-term test, had been done with the workers in Level B protective equipment, they
had had no opportunity to smell the presence of ammonia in the area soils, or in the gas
extracted from the wells during the test. In addition, the laboratory analyses on the associated
soil and gas samples were not programmed for, nor capable of, detecting ammonia.
Therefore, the initial system design included no provisions for accommodating ammonia.
Following this initial failure, the system was modified by addition of an air stream heater,
installed between the water knockout tank and the carbon tanks. Regulatory approval of the
revised design was received and authorization to operate was based on the original Variance
From Permit Requirements. A schematic diagram of the system following the modification
is included in Figure 1.
148
-------
SCHEMATIC OF SOIL VENTING SYSTEM FOR
REMEDIATING DBCP CONTAMINATED SOIL
TO
ATMOSPHERE
t,
UJ
u.
2
d j J WATER WATER
it * FILLED FILLED
WATER U-TUBE U-TUBE
800 '
9H '
43 ,
1300
__2'°°J
13'
560 '
k 260,000
. 2100'
1300
-t
280 ,
53' ,
SANDY SOIL
MEDIUM -FINE '
SAND - NO SILT
SILTY FINE
SAND '
MEDIUM -FINE
SAND
SILTY SAND
SAND - MEDIUM'
TO COARSE
.
FINE SILTY
SAND
, 4
KNOCKOUT
60 GAL. CAP. HEATER 0 | | | |©| j | | @©
1 1 1 T 1 1 ,ITI, 1 .ITT
VALVED 1 1 * • 1 * •
MANIFOLD iC\f~\ 1 1
, ) , .bKiHI ItMP |l |2
3 - r. PVC PIPES 1G^SS CONTROLLER ^ ^
l/U»t? Ht3lkS //w/*f /«s«?
1
750 3 - t/8"0 S.S. TUBES
TO AUTO SAMPLING PUMP
AND ON-LINE GAS
J9 CHROMATOCRAPH WITH
A
BIOWER T t
^99 U
u&it*
. '
ELECTRON CAPTURE DETECTOR
'NO
__ — SCREENED INTERVAL
-- °F WELL (TYP) LEGEND
•T,-— SC SAMPLING COCK
MEDIUM ""
SAND VA VACUUM CAGE
PR PRESSURE GAGE
. F|NE SAND T TEMPERATURE GAC
CALIBRATED
ORIFICE PLATE
AND U-TUBE FOR
FLOW QUANIIFICATION
40 /luuj .
60 _.. _i . J
100. _
FINE TO COARSE
SAND
750« OBCP CONCENTRATION
ON SOIL MQ/Kq BASED ON
SOIL SAMPLING AND ANALYSES
IN 1987, AND 1988
,-,
, V
APPROX. W.S. - VARIES
(O
c
-------
The addition of an electric heater, immediately downstream from the knockout tank, was
intended to maintain the gas stream at a temperature above the point at which water could
accumulate or solids form in the carbon. Also, the revised design included addition of water
filled, U-tube manometers for monitoring the pressure drops through the carbon canisters.
Start-up of the reconfigured VES occurred January 14, 1992, and the operation has been
essentially continuous since then. The balance of this report is devoted to the information
learned from the continued operation.
PROPERTIES OF DEBROMOCHLOROPROPANE
The compound l,2-dibromo-3-chloropropane (DBCP) formerly was widely used in California,
in the fruit and vegetable growing industry, as a soil fumigant for the control of nematodes.
However, since 1979, its use has been restricted to Hawaii, for cultivation of pineapples only,
primarily because of its toxicity to mammals. Acute toxicity studies have identified the
kidneys, liver, and testes as the primary target organs of DBCP. Other properties of DBCP
are:
Melting point
Boiling point
Molecular weight
Specific gravity at 20°C/20°C
Solubility in water at 19°C
6.7°C
195.5°C
236.33
2.5
<1 mg/ml
When used as a fumigant, DBCP is considered to have a half-life in the soil of about 2 years,
but of course, this factor is a variable, depending in large measure on site specific conditions,'
such as soil texture and climate. Probably it is not appropriate to extrapolate this half-life
value to concentrated releases, such as occurred at this site, and where the material has
penetrated tens of feet below the soil surface. It is likely that the material has been toxic to
all or most soil bacteria, at least in the areas where it is or was most concentrated. However,
it is noted that, based on data from investigations conducted at the site in the late 1980s, it
was possible to account for only about 1,000 pounds of DBCP in the site soils. It is further
noted that the time that has elapsed since the spill occurred (about 20 years), the quantity
spilled (about 60,000 pounds), and the residual contamination accounted for in the soil (less
than 1,000 pounds) are qualitatively consistent values for a material having a half-life of 2
to 3 years and a time frame corresponding to about 6 half-lives (64,000 -•- 26 = 1000).
PERFORMANCE MONITORING
To assess the performance of a vapor extraction system it is necessary to measure the
quantity of gas extracted from the soil and the concentrations of target compounds in the
extracted gas. On this project, flow quantification is accomplished by monitoring differential
pressures across a calibrated orifice plate inserted in the system discharge-to-atmosphere
stack. Differential pressures are measured, in inches water column (in. H2O) using a U-tube
manometer connected to the pressure taps provided with the orifice plate. A calibration
150
-------
curve, provided by the plate manufacturer, indicates flows, in cubic feet per minute, as a
function of differential pressures. The VES is equipped with a positive displacement blower
and operated at constant speed. The only significant changes in flow occur as a result of
adjusting the control valves on the pipelines to the extraction wells and thereby the vacuum
against which the blower operates. System flow to date has been within the range of 220 to
260 ambient cubic feet per minute (acfm). The estimated average flow is approximately one
million cubic feet every three days.
The concentration of DBCP in the extracted gas stream is considered the primary variable to
be monitored, for evaluating the performance of the VES. For this purpose, the system is
equipped with an on-line GC that periodically analyses the gas extracted from the ground.
For most of the operation to date, the system has been programmed to sample and analyze
the extracted gas stream every eight hours. In addition, as part of each monitoring cycle,
samples are collected and analyzed from the discharge of each carbon canister, to check for
DBCP saturation in the first carbon canister, and to document that DBCP is not being
released to the atmosphere in the gas discharged from the second canister. Also, in each
analytical cycle, a sample of atmospheric air is analyzed to serve as a system blank. In
Figure 2 is presented a copy of a typical strip chart produced by the GC during one complete
analytical cycle. It may be seen in the figure that a peak for DBCP appeared only in the
analysis of gas as extracted from the soil.
Backup checks to the data generated by the on-line GC are provided by passing calibrated
flows of gas, from the same four sources, through sampling tubes containing granulated
activated carbon (GAC), and submitting the samples to an independent, certified laboratory
for extraction and analyses. These checks are routinely made each time the WCC project
chemist visits the project site to check and adjust the overall system operation (i.e., once
every two weeks). During these site visits, calibration checks are run on the on-line GC. If
the calibration checks indicate that the results have drifted outside the range of acceptable
accuracy the unit is recalibrated and the integrator reprogrammed with a revised response
factor.
Secondary constituents of the extracted gas stream that are routinely monitored are carbon
dioxide, oxygen and ammonia (CO2, O2, and NH3). The concentrations of those three gases
are checked by the project chemist during each site visit. The checks are made using
compound specific, color reactive cartridges (Gastec™) and a hand-held, calibrated, piston-
type pump (Sensidyne™) to draw measured quantities of gas through the cartridges, in
accordance with the manufacturer's specifications. The concentration is indicated by the
length of analyte in the cartridge that changes color, and is read directly from a scale printed
on the cartridge.
151
-------
TYPICAL ON-LINE G.C. PRINTOUT
5TJ3TI
/ Carrier Gas
5-'s» < 5? /DBCP
f.
ST As extracted
from soil
RUM t 2645 SEP/16/92 82=49:36
UORKFILE 10= Al
UORKFILE HftHE-
ID- 1
ESTD
RT AREft TYPE CAL 1 AHOUIH
3.51 9779168 DSBB 6.866
3 74 748938 D PV 6.868
3 89 662346 D VE 6.866
4,86 44657 6V 6.666
4,87 37W56 PP 8.866
S.2&* 126888 PB 6 686
6.41 2 2S64E+87 SBB 1 1.P58
9.46 464868 PB 6.866
TOTAL AREP= 3.4992E+67
MUL FACTOR- 1 .6686E+68
?1 Discharge from
Carbon #1
RVH 1 2646 SEF/1C/92 H4:4%-3<;
UOftKFJLE /O- Al
UORKFUE HAKE
ID 1
NO CALT "-•:: FOUND
RT Af'EA TYPf Aft/HT ftREn^
3 7? "438«6 OTBD 6 881 4'288
1 68 I8.°5Ce D B6 6.664 1.072
TOTAL IfceAs 1 *£24E+fl7
MUI. FACTOR 1 e88eE+«6
5TJKT
-
"" 3.5*
ST Discharge from
Carbon #2
RUN i 2847 SEP/16/92 66=47=42
UORKFILE 10= AJ
UORKFILE NAME:
ID: 1
NO CAL IB PEAKS FOUND
AREA*
RT AREA TYPE Aft/HT AREiV<
3.56 953^466 DSBB 8.866 186.666
TOTAL AREA* 9535486
MIL FACTOR* 1.86eeE+68
•
s
ST Ambient Air
-Blank-
BAfflo. Al SEP/1^92 «'«'«
UORKFILE NAME:
ID: 1
NO CAL IB PEAKS FOUND
AREA*
RT AREA TYPE AR/HT AREA*
3.51 9433286 DSBB 6.666 186. 66f
TOTAL AREA= 9433286
KUL FACTOR= 1.6888E+b6
Figure 2
152
-------
DBCP REMOVAL
The concentration of DBCP in the extracted gas stream is measured by the on-line gas
chromatograph. During the course of the operation, the concentration has varied from about
1 to 13 ppmV. A typical printout from the GC is presented in Figure 2. Figure 3 is a plot
of the average daily DBCP concentration in the gas stream as extracted from the soil. The
plot of Figure 3 is based, generally, on 3 analyses per day. Also shown in the figure is a
schematic representation of extraction history by well. Much of the variation in concentra-
tions may be explained by the well, or combination of wells, being pumped. Clearly, well
VES-1 — screened at 20 to 40 feet below the ground surface — is the most productive of
DBCP and well VES-2 — screened at 60 to 80 feet below ground surface — is the least
productive of the three wells in the system. But none of the wells in the system has exhibited
the type of concentration trend that might be expected for this type of operation (i.e., starting
at a relatively high value, and a uniform progressive decrease in concentration). For example,
well VES-1 started production in mid-January at about 3 ppmV, and this concentration was
sustained for about the first month of operation. Then the concentration increased relatively
quickly (i.e., over about two weeks) by a factor of about 3, to an average of about 10 ppmV,
and this average was generally sustained for about the next two months. This was followed
by a relatively rapid decrease in concentration over the next two weeks — from about 10
ppmV to about 7 ppmV. At that time (April 9) the system was shut down to make piping
changes to allow reversing the order of flow through the two carbon canisters, as would be
required following DBCP breakthrough in the first carbon canister and carbon changeout in
that canister. The system was restarted with extraction simultaneously from Wells VES-1 and
VES-3, and it was no longer possible to track the trend in DBCP concentration for well VES-
1 by itself.
Based on the DBCP concentrations data, summarized in Figure 3, the quantity of DBCP
extracted over time has been estimated (see Figure 4). For example, during the two months
trial program operation the estimated extraction was about 60 pounds DBCP; the next three
months of production operation resulted in an additional 180 pounds DBCP extracted, and
during the next three months of production operation a further 50 pounds DBCP were
removed from the ground. In summary, during the first nine months of operation a total of
about 310 pounds DBCP were removed from the area soils. It appears that the VES
operation to date has made substantial progress towards removing the approximately 800
pounds of DBCP that were estimated, in 1988, as being present in the area soils.
OTHER GASES IN EXTRACTED GAS STREAM
Approximate measurements (Gastec™ tube) of the concentrations of carbon dioxide, oxygen
and ammonia present in the extracted soil gas have been made at about two-week intervals
since the start of the VES operation. Values that are considered to be representative of the
measurements for the three gases are as follows:
153
-------
e am6y
DBCP CONCENTRATION IN EXTRACTED SOIL GAS. DAILY AVERAGE. PPMV
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2. DBCP concentration data from on-Bne O C.
3 Total How horn we*s: 220 10 260 arobtonl
cubic feel per minuta
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Constituent
Approximate Concentrations, ppmV
Low
Median
High
Carbon dioxide
Oxygen
Ammonia
10,000 20,000 to 30,000 70,000
8,000 17,000 to 18,000 20,000
100 1,000 to 3,000 20,000
In general, the carbon dioxide concentration increases as the depth from which gas is
extracted increases, and the oxygen concentration decreases with depth. So far, no other
trends have been detected in the data on these two gases. Ammonia has consistently been
most concentrated in the gas extracted from well VES-3, which is screened from 40 to 60 feet
below the ground surface. There has been a substantial, progressive decrease in the ammonia
concentration in the gas extracted from all three wells in the system.
Throughout the VES operation, the CO2 and O2 measurements have indicated general
agreement, on a mass balance basis, between the oxygen present in the extracted CO2 and the
oxygen deficiency in the gas stream, relative to ambient air. This indicates that the CO2 is
being produced, within the soil mass being vented, at about the same rate as it is being
extracted. It is conjectured that the CO2 is being produced mainly by on-going biological
processes in the soil rather than by purely chemical reactions. The quantity of CO2 extracted
by the VES during the first nine months of operation is indicated by the following
approximate calculation:
• Average soil gas extraction rate:
about 230 cfm; or about O.SSxlO6 ftVday
• Assumed average CO2 concentration in soil gas:
about 25,000 ppmV, or 25,000 ftVlO6 ft3
• Average CO2 extraction rate:
about 8,000 frVday
• Assumed 400 ftVpound mole, at site average temperature and pressure (359
frYmole at STP):
about 20 Ib mole CO2/day
• One Ib mole CO2 = 44 Ib, or 12 Ib C/lb mole CO2
156
-------
• After 270 days of VES operation:
20 Ib mole/day x 44 Ib COj/lb mole x 270 day's
= about 240,000 Ib CO2
or about 65,000 Ib carbon removed from soil
The souice(s) of the extracted carbon is not known. Two candidate sources have been
identified: organic carbon, naturally present in the soil, and the carbon component of the
spilled DBCP. The estimated 3,100 gallons of spilled DBCP would have contained on the
order of about 10,000 pounds of carbon, so clearly DBCP cannot account for all of the carbon
that has already been extracted by the VES. But this does not exclude the possibility that
some fraction of the extracted carbon in the CO2 is the result of in situ biodegradation of
DBCP and or intermediate degradation products of DBCP. ;
In another, unrelated, site investigation, conducted near the subject site, a total of 58 soil
samples were collected and analyzed for total organic carbon. The samples were collected
at depths ranging from 1 to 80 feet below the ground surface, and it is believed the results
of the analyses are generally representative of conditions within the soil mass being affected
by the VES operation. The average organic carbon content of the 58 soil samples was 0.12
percent.
To provide a qualitative appreciation of the quantity of carbon naturally present in the area
soils, the following calculation is provided:
• Assume a cylinder of soil having a radius of 100 feet and a height of 80 feet (these
dimensions may approximate the volume, but not the shape, of the soil mass being
vented):
• Volume of soil in cylinder:
100 x 100 x n x 80 = about 2.5xl06 ft3
• Assumed average dry wt. of soil:
1001b/ft3
Wt. of soil in cylinder:
100 lb/ft3 x 2.5xl06 ft3 = 250xl06 Ib
• Wt. of carbon in the cylindrical mass of soil:
0.0012 Ib C/lb soil x 250 x 106 Ib soil =
about 300,000 Ib carbon
The above calculation clearly indicates that organic carbon, naturally present in the area soils,
can account for all of the carbon that has been extracted by the VES to this time, without
having to make unreasonable assumptions concerning the outlines or dimensions of the soil
mass being vented. It is noted that when only well VES-1 was being pumped, a vacuum of
157
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about 3.8 inches H2O was measured in the riser pipe of well VES-3. The distance between
the two wells is about, 53 feet. This would seem to indicate that in some strata and
directions, the horizontal dimension of the soil mass being vented is significantly more than
50 feet from the extraction well. A semi-log plot of vacuum versus distance from the
extraction well could be extrapolated to indicate a measurable effect probably occurs at 100
feet from the well.
The significance of the ammonia present in the extracted soil gas cannot be quantified with
the presently available information. In general, on-going biological processes in soil, as seem
to be occurring in this case, require more than simply the presence of free oxygen, which is
being supplied by the VES operation. An adequate supply of water and nutrients also is
required. These may be either naturally present in the soil or must be supplied. Because free
water generally is being collected in the knockout tank, it is believed that the air being moved
through the soil generally is at about 100 percent relative humidity and capable of supplying
the water requirements of in situ biological processes. Also, it seems likely that the nitrogen
available in the ammonia is serving as a supplied nutrient. On the assumption that the
nitrogen is necessary for continued, stimulated biological activity in the soil, and that
continuing the activity may be beneficial, with respect to remediating the DBCP
contamination in the soil, we have limited our use of extraction from well VES-3 because it
is the most productive of NH3 in the system. It is expected that pumping of wells VES-1 and
VES-2 causes ammonia present in the vicinity of well VES-3 to flow towards the two
pumped wells. If the ammonia supply is depleted at some time during the operation it will
be interesting to see if it has an effect on the CO2 production rate.
COST INFORMATION
Costs incurred on this project to date, and estimated to the end of the Extension of the
Variance From Permit Requirements — i.e. May 1, 1993 — are summarized as follows:
• Investigation to assess the extent of the contamination, including drilling, sampling,
laboratory analyses, VES feasibility test, and reporting, but not including an on-
going groundwater monitoring program
about $150,000
Cost to design, permit, purchase and install VES
about $200,000
Cost to operate VES for two months trial program, including maintenance, power,
sampling and analyses, and reporting
about $60,000
158
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Estimated costs to operate the VES for one year, (mid-march 1992 to mid-march
1993) including maintenance, power, carbon replacements and disposal, sampling
and analyses, and reporting
about $200,000
Estimated costs to complete closure, assuming VES operation is terminated in
March 1993, including: verification soil borings and soil sampling in Level C
protective equipment, sample analyses, and a final report, but not including any
post-closure monitoring
about $30,000
Total about $640,000
SUMMARY AND CONCLUSIONS
A soil venting/vapor extraction system (VES) was installed to remediate vadose zone soils
contaminated with DBCP. The system causes atmospheric air to flow through the
contaminated soil mass, where it picks up vapor phase DBCP, and is then withdrawn from
the soil through wells installed for the purpose. The system has been in essentially
continuous operation since January 14, 1992. The estimated quantity of DBCP present in
the soil, in 1988, was about 800 pounds. The DBCP spill occurred about 1971, and the
estimated quantity spilled was about 3,100 gallons, or about 60,000 pounds. The maximum
concentration of DBCP found in the soil, in the 1988 investigation, was 260 milligrams per
kilogram. Ammonia is also present in the soil mass being vented, and has been found in the
extracted soil gas at a concentration of up to 2 percent, volumetric.
The installed system includes three wells, each with a 20-foot-long screened section, and with
screened intervals spanning 60 feet, or from 20 to 80 feet below the ground surface. The
contaminated soils are of alluvial origin, moderately stratified, and vary from silty fine sands
to coarse sands with gravel. The depth to groundwater is variable, but generally 90 to 110
feet below the ground surface.
The installed system uses a positive displacement blower, capable of pumping about 220 to
260 ambient cubic feet per minute, with the actual flow dependent on the well, or
combination of wells, being pumped. In general, the blower operates at a vacuum of about
4 to 6 inches mercury column, and discharges to atmosphere.
The extracted soil gas has contained DBCP at varying concentrations, but within the range
of about 1 to 13 parts per million, volumetric (ppmV). The DBCP is removed from the
extracted gas stream by passing it through two canisters of granulated activated carbon,
connected in series, and located on the vacuum side of the blower. The cumulative DBCP
extraction, over the first nine months of system operation, was about 310 pounds. No
estimate is provided of the remaining time the VES will be operated, nor of the concentration
of DBCP in the extracted gas that will serve as a criterion for system shutdown. However,
159
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for cost estimating purposes, we have assumed operation until about March 15, 1993, as
presently covered by the Variance From Permit Requirements, granted by the Department of
Toxic Substance Control, Alternative Technologies Division. It is planned that a soil
sampling and analysis program will be implemented, following system shutdown, to allow
comparison of before and after DBCP concentrations in the soil.
In addition to removing DBCP from the site soils, the VES has removed a large quantity of
carbon dioxide. Through the first nine months of operation, at least 200,000 pounds have
been removed. It appears that the carbon dioxide is being generated at the rate it is extracted
because there is a balance between the oxygen present in the CO2 and the oxygen deficiency
in the gas stream relative to atmospheric air. The carbon in the CO2 must be present in the
soil, because only an insignificant fraction of it can be attributed to the CO2 present in the
air being circulated through the soil. Two possible sources of CO2 have been identified.
They are naturally occurring organic matter and the spilled DBCP. It is possible, but not
documented, that the soil venting has caused stimulation of microorganisms present in the soil
that are capable of biodegrading DBCP and or some of the intermediate degradation products
of DBCP. The ammonia present in the extracted gas stream may be providing nitrogen to
the soil bacteria.
The only waste stream generated by the project is the carbon in the air emissions control
system. The extracted gas stream has, at times, contained water that has collected in an air/
water separator tank located immediately downstream from the valved manifold that controls
the flow from the wells. Initially, the collected water had a pH of about 11, but after about
9 months of operation it had declined to about pH 8 or 9. The decline may be attributed to
the decrease in the ammonia present in the soil as a result of the VES operation. The
collected water has been transferred to a holding tank, from where it has been reinjected into
the extracted gas stream, at a controlled rate, immediately ahead of an air stream heater. The
heater maintains the air stream entering the carbon canisters at a temperature of at least 90°F,
in order to prevent the possible accumulation of water in the carbon canisters or the'
deposition of solids within the carbon, as occurred with the initial design of the system. The
water reinjection process has resulted in all collected water being treated and disposed.
The existing system is being operated under a Variance From Permit Requirements, granted
by the California Department of Toxic Substance Control, Alternative Technologies Division,
and an Extension of the Variance, to May 1, 1993.
The total estimated costs associated with this DBCP remediation project are about $640,000;
including $150,000 for site investigation; $200,000 for design and construction; $60,000 for
a two month trial program operation; $200,000 for one year of production operation; and
$30,000 for a post-operation, verification soils investigation. Post-closure monitoring costs
may be additional.
160
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n
n L
iNGENIEURBURO FUR UMWELT7ECHNIK
1ARBAUER GMBH & CO KG HEERSTRASSE 16 1000 BERLIN 19
5 YEARS OPERATIONAL EXPERIENCE
WITHTHE
HARBAUER SOIL WASHING PLANTS
Winfried Groschel
Harbauer GmbH & Co. KG
Dr. Hansgeorg Balthaus
Philipp Holzmann AG
161
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/. Abstract
Soil washing has become a well established soil cleaning process that offers broad applicability, a
high technological standard and consistent cleaning results. In addition, soil washing provides
production reliability and general acceptance by the public.
The first large scale Harbauer soil washing plant began operation in early 1987 in Berlin. Since that
time a wide range of soil contaminants have been successfully treated. More than 120,000 tons of
soils have been brought from 70 sites to the plant for treatment. In 1990 a mobile HARBAUER soil
washing plant started operation in Vienna.
The high efficiency of the Harbauer soil cleaning process is achieved by using a broad spectrum of
processes partly similar to those commonly used in the mining and mineral processing industries. We
can guarantee optimum cleaning results with relatively low energy consumption by selecting our
mechanical agitation processes based on the grain size fraction.
This year a third generation of soil washing plants is under construction in Berlin with completion
planned for March 1993. In mid 1993 a sophisticated soil washing plant for the removal of mercury
from soil and rubble will begin operation in Bavaria. This plant will use a special vacuum distillation
system to treat fines and other volatile and semi-volatile contaminants.
The main emphasis in the further developments of the HARBAUER soil washing system lies in the
minimization of the residues from the washing process. While we have tested various techniques to
date, vacuum distillation has proven to be the most promising additional step in the soil washing
process. It has proven successfull for a large number of volatile or semi-volatile contaminants such as
mercury, PAHs or other organics.
2.
Introduction
The first large scale HARBAUER soil washing plant began operation in early 1987 in Berlin. This
plant was designed for the treatment of contaminated soil from the former Pintsch used oil recycling
site. This soil was heavily polluted by residues from the oil refining activities. During the operation of
the soil washing plant from 1987 to 1991, the plant engineering was optimized, several treatment
stages were added and the permitted uses of the plant were expanded. This made it possible to treat
soil from other contaminated sites with different contaminants. Up to now more than 120,000 tons of
contaminated soil from approximately 70 different sites have been cleaned successfully.
The gained operational experience has been used for the design of new soil treatment plants. In 1990
a mobile HARBAUER soil washing plant started operation in Vienna. This plant was designed for
the treatment of cyanide contaminated soil and rubble.
This year a third generation of soil washing plants is under construction in Berlin with completion
slated for March 1993. This plant will be a soil washing center for Berlin and its surrounding areas. It
represents the latest developments in soil washing techniques with a broad application spectrum for
different soils and pollutants.
Another soil treatment plant for removal of mercury is under construction in Marktredwitz, Bavaria.
This plant consists of a soil washing unit and a newly developed vaccum distillation unit. It will start
operation in mid 1993.
162
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3. Process Description
To achieve a high cleaning efficiency for different types of soils and contaminants, the HARBAUER
soil washing system uses a multi-step process. Some of the process units are similar to those used in
the mining and mineral processing industry. Others have been developed especially for treatment of
contaminated soils. The primary operational steps of the HARBAUER soil cleaning system that
determine the cleaning efficiency are the following:
Process
Process Equipment
1. Dislodging of contaminants from soil
particles using multi-step mechanical
agitation
2. Separation of highly contaminated grain-size
fractions by means of classification
3. Separation of highly contaminated organic
fractions by means of sorting
4. Exchange of contaminated interstitial water
by means of rinsing and dewatering
- Bladewasher
- Stirring Reactor
- Vibration Reactor
- Hydrocyclones
- Classification Screens
- Mineral Jig
- Fluidized Bed Sorter
- Flotation
- High Pressure Water Sprays
- Countercurrent Hydrocyclone Unit
- Fluidized Bed Sorter
- Dewatering Screens
A simplified flow chart of the HARBAUER soil cleaning system is shown in figure 1. At first,
particles > 16 mm are separated using two classification screens. The oversize material has to be
crushed and can then be added again to the material feed. Usually the amount of material > 16 mm is
less than 1 %. Therefore crushing can be done in batch quantities using a mobile crusher.
The mechanical agitation takes place in three main stages (mechanical agitation I - III). Due to the
fact that the required energy for the cleaning of coarse particles is much smaller than for the fines,
the specific energy input increases in the direction of the material flow. In all agitation stages mainly
shear forces between the particles or between the liquid and the particles are activated. This
guarantees an optimum cleaning efficiency at a relatively low level of energy consumption.
After the dry classification the contaminated soil is conveyed to the first washing unit, a two-stage
blade washer (mechanical agitation I). Before entering the blade washer metal scrap will be
separated. The blade washers are followed by a classification screen (classification stage III) where
the gravel and stone fraction is separated. Before this fraction is discharged as cleaned material, light
materials like tar, wood, etc. are separated using a mineral jig (sorting stage I).
Following the classification of the coarse fraction a multi-stage hydrocyclone unit (classification
stage IV - V) is used to separate the fines < 15 ^m. These particles are concentrated through
flocculation/sedimentation/thickening. Finally they are dewatered mechanically. The second stage for
mechanical agitation is a stirring reactor followed by a fluidized bed sorter for the separation of light
materials from the sand fraction (sorting/rinsing stage n).
163
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The fine particle fraction between
15 jam and 150 \*m is treated in
sorting stage III. This is a two-
stage pneumatic flotation step
where very fine organic particles
are separated. Finally the
HARBAUER vibration screw is
used to dislodge the remaining
contaminants. In this machine the
particles are subjected to intense
vibrations using high amplitudes.
The previous and following
dewatering screen ensure that an
intensive rinsing process of the
cleaned material is achieved.
To avoid any emissions the soil
treatment system is equipped with
a process water and process air
treatment unit. The total amount
of process water which is needed
for an operational capacity of 30
t/h of contaminated soil is 120
m3/h. The water runs in different
circuits. The first treatment stage
for the process water is a large
flocculation/sedimentation unit
consisting of 6 thickeners followed
by a tilted plate separator. This
unit needs to be so large because
the soil treatment plant is able to
treat soil with up to 30 % fines
below 63 [Jim.
Transport •*— — — — __-
Charging |
Material Feed
Classification
Staee I / 200 mm
—i
1
Classification
SHeeIT/60mm
•
-:_,J | Crushing Stage j fW?~V
T (mobile) * \ia£/
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Mech. Aguanon
Staee I
r-» Sorting Stage 1 — » Etewaf™S ». /iSHpy,
Gravel
Clamif. Stage in
2.0-8.0 turn
i
__ ,, Dewnenne i. i
Staee n ...'.. '.
Gravel Fraction
Classification 1 dasaficaaon
Stage IV | Staee V T* Floccuiaaon
Mech. Agitation
Staee II
Sorting / Rinsing
Staeell
Dewitenng
Staee in
\
_ . Classificanon I t v /
Staee VT * ' • ' ' -J
, , Sand traction
Sorting Stage m J Mechanical j ^ ^........y
Dewatenn? I W* f
f
Mech. Agitation
Rinsine Staee 01
Dewitenng
Staee IV
1
Cleaned Soil
Res dues
FlowChan ^^" ££^ _
Harbauer Fa. Harbauer H
foil Wishing hgeaiaatamKr ft
— — , ; 1 Sy!ittm 11'm^lr.x.hn.fc H_
Fig. 1 Simplified Flow Chart
Light substances such as oil flow separately to a dissolved air flotation unit where they are separated.
The cleaned overflow of the tilted plate separator is split into three streams. Stream I is directly
reused in the first washing step of the soil treatment (circuit 1). Stream II is filtered using sand filters
and then reused (circuit 2). The third stream of the process water is cleaned using the treatment
stages of oxidation/precipitation and activated carbon adsorption. The operation of the oxidation and
precipitation stages is optional and only used for heavy metals and cyanides. The cleaned water
leaving the activated carbon adsorption stage is reused in the final rinsing processes of the soil
treatment. Approximately 15 m3/h of this water is discharged and replaced by clean water. The
sedimented solids are dewatered using chamber filter presses.
In the process air treatment unit 30,000 m3/h of air is cleaned. 15,000 m3/h are collected from the
resource material feed/dry classification/intermediate storage areas. Dust is first removed from this
Stream and then together with the other collected air stream finally cleaned using activated carbon
adsorption. The quality of the discharged air is controlled on-line using a TOC-monitor. Furthermore
the cleaned air stream will be regularly tested in a laboratory.
164
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4. Design
HARBAUER soil washing plants are subdivided in four main areas. Area I consists of a 1,000 m3
intermediate storage area for contaminated soil, the material feed and screens for dry classification at
200 and at 60 mm. If necessary a crusher can be integrated into the process here. To avoid
emissions, this area is a closed hall provided with material locks and rolling bars. The soil is
transported from here to area II using an enclosed belt-conveyor. Area n consists of all wet
mechanical separation processes and the dewatering stages for the residues. Areas III and IV are the
process water and process air treatment units. Rgure 2 shows a top view of the Berlin soil washing
plant with the required infra-structure. The minimum required space for a soil treatment plant of that
size is 8,000 m2. The whole site is subdivided into sections:
intermediate storage and material feed:
soil washing plant:
intermediate storage for cleaned soil:
storage area for containers:
roads, offices, etc.:
700m2
1,600 m2
700m2
1,000 m2
4,000 m2
n
>-
1
GBCHZC G«*OtSTB*nl
PROCESS AIR
1^ n n n n n
c
1&\-
D HALL FOR n
THICKENERS/TANKS U
-
n
O~ SOtt. TREATMENT pi pi
CeH UNIT
(£__ ,
F™"*""*"™!
SANDySILT
LJ t
l^-l GRAVEL
^S • i »r-lr.-i
JL CLEANED MATERIAL
(T) DISCHARGE
(
r -- r — i — i \
' INTERMEDIATE STORAGE 'l
| FOR CLEANED SOIL •'
= \ \ I I
". m 1 i 1
juDDDDQuLUi
I
— , ,
PROCESS WATER
TREATMENT UNIT
n n n a
a a a
RESIDUES
DISCHARGE
JUUU
UUUU
SPECIAL CONTA
CONTAMINATE]
SSSB
D i
i
~T
(t
;
,
I
BELT CONVEYOR (T; (C
JZT-, =t j.
/^
=
^w-
JNEF
3 SO
)
INT
FOB
SFOR
L/RESIDUl
ERMEDIATE STORAGE
CONTAMINATED SOIL
'
£S
MATERIAL
*
l
t
D
^
i
FEED
_-
-T)
s
1
Fig. 2 Top View of the Soil Washing Plant Berlin
165
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An example for the modular design of one of our plants is shown in figure 3. The whole plant
consists of 50 containers that are 3 m wide, 3 m high and with a length of 10 or 14 m. The individual
containers are prepiped and prewired with quick interconnections. This makes a rapid mobilization
or demobilization possible which is very important for timely delivery and cost effective use during
on-site treatment.
Fig. 3 Example for the Modular System Design
166
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5. Contaminant Specific Suitability
The most operational experience gained thus far has been gained with organic contaminants
specifically TPHs and PAHs. For TPHs the input concentrations varied between 500 and 20,000
mg/kg and for PAHs between 500 and 5,000 mg/kg. The residual concentration in the cleaned soil
has typically been < 100 mg/kg for TPHs and < 5 to 10 mg/kg for PAHs. In some unusual cases of
very high input concentrations, the maximum residual concentrations have been 300 mg/kg for TPHs
and 20 mg/kg for PAHs. Figure 4 shows typical examples.
10000
1000
Example!: PETROLEUM CONTAMINATED SOIL
(PROJECT: RUNGIUSSTR, BERLIN)
CONCENTRATION TPH (mg/kg] REMOVAL [%]
= 100,0
80,0
REMOVAL [%]H
Input (mg/kg]»
Output (mg/kg] d
10000,00
Example 2: TPH, PAH CONTAMINATED SOIL
(PROJECT: Plntsch, BERLIN)
CONCENTRATION [mg/kg]
REMOVAL [%]
100,0
1000,00 fe
60,0
REMOVAL (%]H
Input (mg/kg] •
Output (mg/kg] d
Fig. 4 Examples for Treatment Results of Soils Contaminated with Organics
167
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The clean-up efficiency for volatile organic contaminants like chlorinated solvents or BTEX is very
good. The residual concentrations always have been below the detection limits. For PCBs the input
concentrations have been relatively low ranging from 5 to 25 mg/kg. The residual concentration has
consistently been < 0.1 mg/kg or below the detection limit
Soil washing is also an effective treatment method for heavy metal or cyanide contaminated soil.
Examples are given in figure 5.
Example 3: HEAVY-METAL CONTAMINATED SOIL
(PROJECT: TRE1DELWEG, BERLIN)
10000
CONCENTRATION [mg/kg]
REMOVAL (%]
100,0
80,0
REMOVAL [%]H
Input [mg/kg] •
Output [mg/kg] E3
EXAMPLE 4: CYANIDE CONTAMINATED SOIL
PROJECT GASAG (FORMER MGP-SITE)
1000
CONCENTRATION [mg/kg]
REMOVAL [%]
Fig. 5 Examples for Treatment Results of Soils Contaminated with Heavy Metals and Cyanides
168
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6. Technical/Operational Data
The most relevant technical and operational data of the HARBAUER soil cleaning system is shown
in figure 6.1. The operational capacity ranges between 25 and 40 t/h depending on the amount of
fines in the soil. The annual capacity is 100,000 tons for two-shift-operation and 160,000 tons for
three-shift-operation. We have proven that this capacity is sufficient for a stationary plant
OPERATIONAL
CAPACITY
WASHING CAPACITY
TREATMENT
RESIDUES
LIMIT FOR
APPLICATION
SPEC. ENERGY
CONSUMPTION
SPEC. WATER
CONSUMPTION
OPERATIONAL
MATERIAL
QUANTITY OF WASTE
WATER/
OUTGOING AIR
FLOOR SPACE
REQUIRED
25 - 40 t/h depending on the portion of fines < 63 \m
The maximum washing capacity depends on the texture of the soil, the
concentration and the kind of bindings of contaminants. Treatability tests
are necessary to determine the minimum achievable residual concen-
tration. The following concentrations for cleaned material are guide
values refering to our operational experiences.
TPH PETROL. HYDROCARB. 10.0 - 200.0 ppm
BTEX 0.5 - 5.0 ppm
PAH (EPA) 1.0 - 20.0 ppm
HALOGEN. VOL. ORGANICS 0.5 - 5.0 ppm
PCB 0.5 - 10.0 ppm
PHENOLE(EPA) 0.5 - 5.0 ppm
CN (total) 1.0 - 20.0 ppm
Hg 1.0 - 50.0 ppm
Pb, Cu, Ni 50.0 - 300.0 ppm
Cd 1.0 - 20.0 ppm
- FINES < 15 Mm
- SEPARATED ORGANICS
- LOADED ACTIVATED CARBON
PORTION OF CLAY/SILT: max. 30 - 40 %
ca. 12 kWh/t
ca. 200 - 1,000 1/t
- FLOCCULANTS
- HC1, NaOH (pH-adjustment if required)
- SURFACTANTS (if required)
- ACTIVATED CARBON
INTEGRATED PROCESS WATER AND AIR TREATMENT UNIT:
CLEANED PROCESS AIR: 15,000 - 30,000 mYh
CLEANED PROCESS WATER: 200 - 1,000 1A
SOIL WASHING PLANT: 1,000 - 2,000 m2
MAX. HEIGHT: 20 m
ROADS, INTERMEDIATE
DEPOSITS FOR CLEANED AND
UNTREATED MATERIAL, ETC.: 8,000 - 10,000 m2
Fig. 6 Technical/Operational Data of the HARBAUER Soil Washing System
169
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The energy and water consumption of the treatment process is relatively low. The specific energy
consumption is 15 kWhA or approx. 450 kWh/h. The specific water consumption ranges between
200 and 1,0001/t and depends mainly on the type of soil and the input water content.
Additives used in the process are flocculants for the sedimentation, HC1 and NaOH for pH-
adjustment and activated carbon for the process water treatment. Surfactants are only used in special
cases when otherwise the required treatment results cannot be reached.
Soil washing is a volume reduction process which concentrates the contaminants in the fine particle
fraction of the soil. The economic limit for the application of soil washing is established generally by
the portion of clay or silt in the soil. The clay/soil fraction should not exceed 30 to 40 % of the
volume. This limitation exists because the amount of residues which remain following washing of soil
with more than 40 % clays will increase to such a point that the additional landfill and post treatment
costs plus the reduced operating capacity will push the soil washing per ton costs into the non-
competitive range. To help minimize the amount of residues the cut-off point of the HARBAUER
soil washing process is as low as 15 \un. In additional to the fines, solid organic matter such as roots,
leaves, humus, etc. with a high affinity to contaminants must be separated. The soil washing process
will generate a small quantity of loaded activated carbon as a waste by-product.
The quantity of filtered air ranges between 15,000 and 30,000 m3/h and the cleaned process water
discharge ranges between 200 and 1,000 1A.
7.
Costs
The investment cost for a large scale stationary soil washing plant is approximately 19 millions DM
or 12 millions US$. The costs can be broken out as follows:
Earthworks, foundations, subsurface sealings, etc.
Steel construction, buildings
Equipment
Infrastructure
2.5 millions US$
3.0 millions US$
6.0 millions US$
0.5 millions US$
It should be noted that these are the investment costs for a stationary, multi-functional plant which is
able to clean many soils with different textures and contaminant characteristics.
The specific operating costs are shown below:
• Power:
• Water/waste water
• Additives, activated carbon
• Analytics
• Labor
4.00 US$/t
2.80 US$/t
5.30 US$/t
3.00 US$A
15.00 US$/t
These numbers are specific for German costs and conditions. Most important for the specific cost per
ton is the rate of utilization. Figure 7 shows the specific cost depending on the rate of utilisation for a
plant with an annual capacity of 100,000 tons. If the plant is running at full capacity, the total costs
are 70.— US$/t. If the rate of utilisation is only 50 %, the cost will be as high as 120.-- US$/t. These
prices do not include any cost for the post treatment or deposition of residues. The most cost
effective way to run a soil washing plant however is the treatment of big quantities of soil from just
one remediation site with a specially designed plant
170
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TREATMENT COSTS SOIL WASHING [ US $ /1 ]
STATIONAL PLANT: .
MAX. OPERATIONAL CAPACITY: 100.000 Va in 2 SHIFTS
300
CO
is
8
O
o
0.
CO
200-
100-
0 10 20 30 40 50 60 70 80 90 100
RATE OF UTILIZATION [%]
Fig. 7.1 Soil Washing Cost Relative to the Rate of Utilization
8. New Developments
The main thrusts in our soil washing research is to reduce the amount of residues which have to be
post treated and to increase the application spectrum. One method is to use a flexible separation limit
for the fines which goes down even below 15 nm in grain-size. By using this method, it is possible to
adjust the optimum separation point for each type of soil which has to be cleaned. By doing this, the
amount of fine particle residues is minimized.
In some cases of heavy metal contaminated soil it is possible to reduce the level of contamination
significantly by soil washing but the required limits may not be reached. Then a chemical extraction
using low concentrated acids is applicable. Results of tests which have been done with a lead
contaminated soil are shown in figure 8.1. The input concentration in the range of 40,000 to 60,000
mg/kg was reduced under the required level of 150 mg/kg. After the treatment the fine particle
fraction showed very high lead concentrations so that this material was suitable for metallurgical
recycling. Chemical extraction without soil washing was also tested but was not successful.
171
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The most promising new techology is the vacuum distillation system. This technology can be used as
additional treatment step for the fines following the soil washing process or directly for soil which
cannot be washed due to very high concentrations of silt/clay or contaminants. It has proven that
soils contaminated with volatiles like BTEX, solvents or mercury as well as semi-volatile
contaminants like TPHs and PAHs can be cleaned
The process uses pressures in the range of 50 to 150 hPa and temperatures between 300 and 400 °C.
To ensure that no dioxines are produced, the process works under inert conditions.
Figure 8.2 shows the boiling points of the EPA PAHs under normal pressure. It can be seen that the
vacuum is necessary to reduce the boiling points of such semi-volatile substances. Figure 8.3 shows
the results of laboratory scale tests for soil from a former coking plant. The removal of the input
concentration has been > 99.9 % for PAHs, > 99 % for TPHs and even 99 % for cyanides.
CONCENTRATION OF LEAD (g/kg)
INPUT
AFTER SOIL WASHING
AFTER CHEM. EXTRACTION
Fig. 8.1 Treatment Results - Combined Soil Washing and Acid Leaching Process
172
-------
IU
ee
I
UJ
500
480
460
440
420
400
380
360
340
320
300
280
260
240
220
200
Fig. 8.2 Boiling Point of PAHs (EPA standard) at 1,013 hPa
100000
Fig. 8.3 Treatment Results Vacuum Distillation
173
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9.
Outlook
By using the HARBAUER soil washing system it is possible to clean soils with multiple complex
pollutants and problematic particulate composition. The system allows the soil to be rapidly cleaned
at site and immediately be used as backfill. As a result of the removal of clays and silt the cleaned
backfill material has a greater loadbearing capacity than the original soil prior to the washing.
We have experience from over 70 sites producing more than 160,000 tons of soil. The sites include
refineries, chemical plants, oil recovery facilities, process plants, landfills, and marine environments.
The range of contaminants includes hydrocarbons, cyanide, heavy materials, mercury, lead, VOC,
PAH, PCB, and others. In many of the soils more than one contaminant was present. Inspite of the
field experience we have gained over the years we still believe that a treatability study must be done
with each type of soil to be cleaned. Harbauer performs inhause the full range of services from
treatability studies to equipment fabrication and from plant operation to the design of special
treatment plants for unusual contaminated sites.
By 1993 there will be three large scale HARBAUER soil washing plants in operation plus other
smaller scale operations. HARBAUER is also presently involved in the planning of four other soil
treatment centers in Germany. Much of this growth and extensive research and development is
possible as a result of the acquisition of HARBAUER by the Philipp Holzmann Company. Holzmann
is Germany's largest civil engineering company and ranks in the top 10 in the world with over $ 10
billion in revenues. During the lat 12 years Holzmann has been aggressively entering the
environmental remediation field through both acquisitions and internal development. Engineering
News Record recently named Holzmann as one of the largest environmental contractors in the
world.
If you have soil washing problems that you would like to discuss with us, we operate in the U.S.
through J.A. Jones Construction Company of Charlotte, North Carolina. Jones is also a member of
the Holzmann Family of companies.
We believe that soil washing will become a more acceptable method of remediation in the U.S. as
landfill space decreases and the costs for incineration rise. Soil washing is not a panacea for every
site but when applied to the proper set of circumstances is a quick and cost effective method for
remediation of soil contamination.
174
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HELD DEMONSTRATION
of
SOIL WASHING
at the
KING OF PRUSSIA SUPERFUND SITE
MICHAEL J. MANN, P.E.
ALTERNATIVE REMEDIAL TECHNOLOGIES, INC.
and
HANS VAN DORD
HEIDEMIJ RESTSTOFFENDIENSTEN
175
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FIELD DEMONSTRATION OF SOIL WASHING AT THE KING OF
PRUSSIA SUPERFUND SITE
Overview
A soil washing demonstration run was conducted at Moerdijk, The Netherlands, on July
22, 1992. The demonstration run was conducted on soils from the King of Prussia
Technical Corporation Site (KOP) in Winslow Township, New Jersey by Alternative
Remedial Technologies, Inc. (ART) a Joint Venture Company of Geraghty & Miller,
Inc. of the U.S.A. and Heidemij Reststoffendiensten of The Netherlands.
Site investigations had been accomplished through a Remedial Investigation (RI) and
expanded by a Supplemental RI. The RI was further enhanced by the excavation of a
number of test pits. The test pits provided an excellent means to physically examine the
disposition of the target soils. Soil washing was selected as the remedy for the metals-
contaminated soil at the site in the United States Environmental Protection Agency's
(USEPA's) Record of Decision (ROD) dated September 28, 1990.
To define the soil washing system, a detailed treatability study was performed under the
EPA's "Guidance Document for the Performance of Treatability Studies under
CERCLA". The study was completed in March, 1992 and later approved by the
USEPA. The treatability study confirmed the process and optimized the system
configuration. The study did, however, leave some questions unanswered, and to
further confirm the process, a "Demonstration Run" was proposed to be conducted at
the full-scale Heidemij plant in The Netherlands.
First, approvals to ship the demonstration soils were obtained from the USEPA under
the Resource Conservation and Recovery Act (RCRA) Export Rule and then from the
Dutch VROM, the equivalent USEPA organization. For the demonstration run,
representative soils were excavated, field-quantified using the Environmental Resources
Management, Inc. (ERM) X-Ray Fluorescence (XRF) equipment, bagged in "super
sacks", and placed in sea-going shipping containers. The containers were transported to
the Port of Newark and then, by sea, to the Port of Rotterdam. In Rotterdam, the
shipment cleared customs and was transported by land to the Moerdijk treatment
facility.
At Moerdijk, the site soils were screened, blended, and processed in a state-of-the-art
soil washing facility using an integrated system of screens, hydrocyclones, flotation
cells, dewatering equipment, thickeners, and a belt filter press. The run lasted
approximately seven hours during which time samples were collected from various
intermediate stages, and, most importantly, from the process residuals, namely: sand
product, sludge cake, and oversize materials.
The collected samples were first analyzed by Daniel C. Griffith (Holland) B.V. (D.C.
Griffith), a multi-national environmental laboratory operating in The Netherlands.
Split samples were analyzed by IEA Labs, a U.S. Contract Lab Program (CLP) Lab.
176
-------
These data were consistent and confirmed achievement of the soil cleanup levels
specified in KOP ROD.
The process residuals were returned to the U.S. on October 17, 1992. The oversize and
the product sands were returned to the KOP site as clean, while the sludge cake was
disposed at the GSX Pinewood Treatment, Storage and Disposal Facility (TSDF).
Preparation Activities
Excavation Plan
The excavation of target soils at the site was performed in accordance with a
demonstration run plan. The original plan was to collect 200 short tons of target
materials to be placed in 200 super sacks, but, due to lower than expected soil densities,
the total amount of material collected was 164 short tons.
The material was shipped from the site to the Port of Newark, then to the Port of
Rotterdam, and downloaded for the trip to the soil washing facility located at Moerdijk
(near Dordrecht), The Netherlands.
At the Moerdijk site the soil was first rough screened in its received state at 4
centimeters (cm). A "gross oversize" fraction was defined as that material >4 cm, and
consisted of less than one ton, comprised mostly of plants, tree roots, and some hard
lumps of sludge. The gross oversize material was bagged for return to the site where
debris-washing studies will be conducted. The underfall material, that is everything
<4cm, was blended and staged as the process feed material.
Process Plant Configuration
The process plant was configured exactly as recommended in the KOP Treatability
Study.
The plant consisted of the following primary subsystems:
• The Feed Hopper and Conveyor
• The Wet Screening System
• The Separation System, including Hydrocyclones
• The Flotation System, including the Contact Scrubber and Surfactant Addition
• Sand Dewatering and Conveying
• Lamella Clarifiers and Thickeners
• A Belt Filter Press and Conveyer
Systems available at the Moerdijk Plant that were not used for the demonstration run
included the spiral concentrators, the 500 micron screen, and the sieve bend. These
subsystems were intentionally bypassed in order to match the proposed configuration
determined from the Treatability Study.
177
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Chronology of Demonstration Run Activities
The key activities of the demonstration run were:
May 24, 1992
May 30, 1992
May 31, 1992
June 14, 1992
June 24, 1992
July 18, 1992
July 22, 1992
July 24, 1992
August 21, 1992
October 17, 1992
Data Collected
Soil excavation began.
Soil bagging and containerizing complete.
The SV Sextant sailed for Rotterdam.
Soil arrived in Rotterdam.
Soil downloaded and arrived in Moerdijk.
Soil screened and plant cleaned out.
Demonstration run performed.
Preliminary data presented to USEPA and discussed.
Demonstration Run report submitted to USEPA Region II.
Treated soils returned to the U.S.
Detailed data were collected to evaluate the process and the effectiveness of the
treatment as measured by the ROD Soil Cleanup Standards. The data were verified by
split sample analyses using a CLP-qualified laboratory. Based upon averages from data
developed, successful compliance with the required standards was achieved.
Treatment Products. Tmg/kg)
Source
Cleanup Goal
Process Feed
Oversize
Sand
Sludge Cake
£E
483
770
420
170
4750
Qi
3571
1500
790
350
8030
m
1935
460
540
70
2630
Detailed data is included in Tables 1 through 12
178
-------
Disposition of Process Residuals
The oversize material and the product sand meet the treatment standards and will be
staged onsite and later incorporated into the restoration of the site. The gross oversize
material will be returned to the site and staged for additional studies to determine
whether a debris-washing system is appropriate for use in attaining additional volume
reductions by removing fines from the material. The sludge cake has been disposed at
an appropriate off-site facility.
Conclusions
Key conclusions drawn from the performance of the demonstration run were:
1. The system as recommended in the Treatability Study can treat the KOP soils to
levels in compliance with the requirements of the ROD.
2. The distribution of the process residuals indicates that, on a dry solids basis,
approximately 13% of the material introduced into the plant will require off-site
disposal.
3. That several design modifications for the KOP plant will improve the operations of
the facility on-site; specifically improvements in wet screening and in sludge cake
production.
The Gross Oversize, the Oversize, and the clean sand will be returned to the site. The
sludge cake consisting of approximately 55% dry solids or now approximately 20% of
the total soil treated will be disposed at an off-site facility.
For more information about this project and soil washing, contact Michael J. Mann,
P.E., Alternative Remedial Technologies. Inc.. 14497 North Dale Mabry Highway,
Suite 140, Tampa, Florida 33618. Telephone (813) 264-3506.
179
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TABLE 1
MATERIAL TO BE TREATED
King of Prussia Technical Site
Demonstration Run
Moerdiik. The Netherlands
July 22. 1992
(All tons)
Source
Sludge Band
Swale
Lagoon 1
Lagoon 6
Total
. Target *
145 (72.5%)
5 (2.5%)
25 (12.5%)
25 (12.5%)
200
Actual
122 (74.4%)
3 (1.8%)
21 (12.8%)
18 (11.0%)
164
Gross Oversize
0.5
<0.1
-0.25
-0.25
-1.0
Process Feed
121.5
3
20.5
18
163
A nominal 200 U.S. tons of material were targeted for treatment in the soil washing process.
Actual quantities received were 164 tons with a percentage relationship very similar to the
targeted ratios. All source materials were dry-screened at 4 cm and yielded a gross oversize
totaling nearly one ton. Lagoon 1 and 6 sludge, planned to be pre-screened dry as 1 cm,
were found to be too wet and approval was given by the KOP Remedial Project Manager
to conduct 1 cm screening on the 2 mm process oversize at the completion of the run. That
data is contained in Table 3.
180
-------
TABLE 2
PROCESS FEED MATERIAL
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
Influent Concentrations
(All mg/kg)
Saiople *
;•
1
2
3
4
5
6
7
8
9
Average
Cr
DCG
790
745
705
705
910
815
855
710
735
770
IEA
872
759
982
1080
675
870
Cu
DCG,
1600
1600
1300
1400
1850
1900
1500
1250
1250
1500
IEA,
1470
1080
2170
1310
1110
1430
Ni
D€G
433
415
408
420
660
473
460
393
435
460
-IEA
409
357
639
368
378
430
Dry Solids
<%)
83.5
83
85.5
85
82
85
83.5
86
86
84.4
Per the agreed plan, all discrete process materials were mixed into a feed blend pile.
Results of this activity were captured on video tape.
Efficiency of the blending operation and feed to the plant was measured via a series of nine
(9) radial hollow stem auger borings, analyzed for contaminant metals chromium, copper
and nickel. In addition, five (5) samples were split for CLP analysis by IEA Laboratories
in the United States.
Analysis of the nine samples by D.C. Griffith showed good consistency with averages and
ranges for each metal. CLP analysis by IEA on five split samples showed similar consistency
and close agreement to the results generated by the Dutch laboratory. From these data, it
was concluded that the feed pile was sufficiently blended to introduce a consistent feed to
the process.
181
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TABLES
PROCESS OVERSIZE
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
(All mg/kg)
Material
s *•
"
<4 cm >2 mm
Initial Feed (10%
misplacement)
<4 cm >2 mm
Reprocess O/S
< 4 cm > 1 cm
Screened
< 1 cm > 2 mm Screened
Concentrations""
Cr "
DCG
890
420
270
540
IEA
696
305
185
408
Cii
DCG
1400
790
335
800
IEA
1220
617
300
700
Ni
..A"* ;$ f
DCG
1200
540
970
730
IEA
932
345
730
498
%Dry
2 mm which meets the treatment requirements.
182
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TABLE 4
PRE-FLOTATION PRODUCT
King of Prussia Technical Site
Demonstration Run
Moerdiik. The Netherlands
July 22. 1992
mg/kg
- — / 'Cr \ :' :, ':., '
. ] r^ .c^il T * :
- ""Ni '- '
% DJ^ Solids
375
680
170
76%
*No splits on this sample.
This sample was a composite of samples taken every 30 minutes during processing. This
sample was taken from the underflow of Cyclone #1.
183
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TABLES
FLOTATION IMPACT
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
Sand Product
mg/kg
Process Step v" " ' x"
* -S** " K • f v-> s
s ' % >
Pre-Flotation Composite
Final Sand Product (Avg. composite of
15 Data Points)
Contamination Reduction
Percent of Flotation Input
Cr
375
170
45%
Ott -
680
350
51%
. NT'
_, s
170
70
41%
%£>ry
Solids
76
84
This table demonstrates that the use of the flotation step provides a significant reduction
in contamination residing on the sand. Flotation provides an important protection to make
sure that the sand returning to the site meets the clean-up standards.
184
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TABLE 6
PRODUCT SAND
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
(All mg/kg)
Sample
1 - 0900
2 - 0930
3 - 1000
4 - 1030
5 - 1100
6 - 1130
7 - 1200
8 - 1230
9 - 1300
10 - 1330
11 - 1400
12 - 1430
13 - 1500
14 - 1530
15 - 1600
16 - 1630
Average
Treatment
Requirement
- Cr
DCG
IEA
Oi
DCG
IEA
Ni "
DCG
IEA,
,%Dry
Solids
No sample taken, sand not discharging
98
250
185
130
115
155
76
150
140
140
235
185
205
220
205
170
483
266
97
161
129
183
195
170
195
465
370
270
240
315
145
305
280
310
520
455
465
445
430
350
3571
668
187
353
258
428
429
390
41
105
73
53
46
67
33
63
54
65
120
87
97
91
89
70
1935
119
43
77
66
98
99
80
90
81
83
84
84
83
84
84
84
84
81
83
86
83
83
84
ERM Split Sample #13 was broken during shipment. This
be placed back on the site. It clearly meets the treatment
product sand is the material to
requirements.
185
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TABLE?
SLUDGE CAKE RESULTS
King of Prussia Technical Site
Demonstration Run
Moerdiik. The Netherlands
July 22. 1992
(All mg/kg)
Sample
1
2
3
4
Average
'••• --.•:• Or
DCG
4400
4400
4700
5500
4750
IEA
4470
4760
4615
Cu
DCG
7300
7400
8100
9300
8030
TEA
7330
7950
7640
Ni
DCG
2300
2300
2700
3200
2630
JEA
2360
2670
2515
% -Dry Solids
44
46
46
44
45
This table tabulates the results of the produced sludge cake. The sludge cake contains the
treated contaminants and will be disposed at an appropriate off-site facility. Work will be
focused on improving (increasing) the produced sludge dry solids concentration. A
reasonable goal is 55% dry solids.
186
-------
TABLES
SLUDGE CAKE RESULTS - TCLP METALS
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
IEA Analyses Only
TCLP
1 Metal
Arsenic
Barium
Cadmium
Chromium
Mercury
Lead
Selenium
Silver
Regulatory-
Standard
(mg/1)
5.0
100
1.0
5.0
0.2
5.0
1.0
5.0
Results
Sample Number (i»g/l)
, 1
<0.61
<14
<0.12
2.1
<0.02
<0.65
<0.11
<0.60
2
<0.61
<17
<0.12
1.8
<0.03
<0.71
<0.11
<0.60
3
<0.62
<48
<0.12
<0.65
<0.02
<1.0
<0.11
<0.60
4 '
<0.63
<37
<0.12
<0.67
<0.02
<0.96
<0.11
<0.63
The TCLP Metal Analyses confirm that the produced sludge cake does not exceed TCLP
regulatory standards. The sludge cake is not the product of the treatment of any listed
RCRA hazardous waste and does not demonstrate any hazardous characteristics. Therefore,
the sludge cake is not a RCRA hazardous waste.
187
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TABLE 9
PROCESS WEIGHT COMPARISON
King of Prussia Technical Site
Demonstration Run
Moerdiik. The Netherlands
July 22. 1992
Feed
In/Out as Weighed
' ' (tons) '
163
% Dry Solids
x\
0.844
Dry Solids in Tons
137.5
Products
> 1 cm O/S
< 1 cm O/S
Sand Product
Sludge
Total
Recovery
9.92
12.56
104.20
36.56
163.0
—
0.96'
0.90'
0.953"
0.479"
...
—
9.5
11.3
99.3
17.5
137.5
100%
*_- Measured by DCG and adjusted for overnight drying
" - Measured by HRD
This table documents a mass balance for the demonstration run. The recovery is excellent,
and the mass distribution of produced sludge is reasonable.
188
-------
TABLE 10
CHROMIUM MASS BALANCE
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
Feed
Dry Solids in Tons
137.5
Cr mg/kg
DCG
770
IEA/
870
Cribs
DCG '
212
IEA
239
Products
> 1 cm O/S
< 1 cm O/S
Sand Product
Sludge
Total
Recovery
9.5
11.3
99.3
17.5
137.5
—
270
540
170
4750
—
...
185
408
172
4615
—
—
5
12
34
166
217
102%
4
9
34
162
209
87%
This table demonstrates the mass balance and recovery for chromium. The concentrations
for DCG use all data, while the IEA uses the split sample results. In both cases, the
recovery was excellent.
189
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TABLE 11
COPPER MASS BALANCE
King of Prussia Technical Site
Demonstration Run
Moerdijk. The Netherlands
July 22. 1992
Feed
Dry Solids in Tons
137.5
Cu mg/kg
DCG
1500
IEA
1430
Culfas
DCG
413
IEA
393
Products
> 1 cm O/S
< 1 cm O/S
Sand Product
Sludge
Total
Recovery
9.5
11.3
99.3
17.5
—
—
335
800
350
8030
—
—
300
700
387
7640
...
—
6
18
70
281
375
91%
6
16
77
267
366
93%
This table demonstrates the mass balance and recovery for copper. The concentrations for
DCG use all data, while the IEA uses the split sample results. In both cases, the recovery
was excellent.
190
-------
TABLE 12
NICKEL MASS BALANCE
King of Prussia Technical Site
Demonstration Run
Moerdiik. The Netherlands
July 22. 1992
Feed
' Dry Solids In TORS
137.5
Ni mg/kg
DCG
460
IBA
430
Niibs
DCG
127
IEA
118
Products
> 1 cm O/S
< 1 cm O/S
Sand Product
Sludge
Total
Recovery
9.5
11.3
99.3
17.5
—
—
970
730
70
2630
—
—
730
498
84
2515
—
—
18
16
14
92
140
110%
14
11
17
88
130
110%
This table demonstrates the mass balance and recovery for nickel. The concentrations for
DCG use all data, while the IEA uses the split sample results. In both cases, the recovery
was excellent.
191
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The Lurgi-DECONTERRA Process
Soil Washing
Commercml DECONTERRA® plant under construction
Dr. Eckart Kilmer
Ted J. PoUaert
192
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The DECONTERRA® process
is a multi-stage wet
mechanical separation
process for the remediation of
contaminated soil (organics
and inorganic compounds),
building rubble and railway
ballast.
As extraction agent, water is
used commonly without any
addition of detergents,
solvents, emulsifiers or acids.
In addition to the size
separation procedure, it uses
sorting techniques for
separating contaminated
particles from the clean bulk.
This is why soil types with
extremely high silt or clay
contents can still be treated
economically.
The development of this
process is based on Lurgi's
know-how in the field of wet
mechanical processing of
minerals, especially of ores
and salts, as well as of sludges
from stagnant and running
waters, and on the equipment
experience, which Lurgi has
gained building such plants.
DECONTERRA® Process
CONTAMINATED SOL (FEED)
LIGHT MATERIAL
(CONTAMINATED)
HEAVY MATERIAL
(CLEAN)
CONTAMINATION
193
-------
Process Description
The contaminated soil is
reclaimed, fed to a grizzly,
' followed by a vibratory
screen.
The coarse fraction is crushed
and, together with the fine
fraction, is transferred to a wet
attritioner drum.
In the attritioner drum, the
bulk of the adhering pollutants
is rubbed off with a controlled
input of energy and first of all
suspended in the liquid and
then bound adsorptively to the
fine particles of the soil.
The energy required for the
attrition is matched to the type
of soil and the character of the
contamination, up to 10
kWh/ton being transferred to
the material. The material
discharged from the drum is
screened in several stages.
The fraction over 20mm is
returned via the crushing
cycle back to the attrition
stage. The l-20mm fraction is
either discharged from the
process as purified end
product or subjected to a
gravimetric sizing, the heavy
material being discharged
clean, whereas the light
material, such as
contaminated coarser coal, tar
and wood particles, being
obtained as a pollutant
concentrate.
Of the fraction under 1mm, the
finest fraction is cleared from
mud and transferred to a
hydrocyclone, the overflow of
which is concentrated.
The cyclone underflow,
together with the deslimed
coarse fraction of the
classifier, is introduced into
the 2nd attrition step and
subjected to a further
purification.
The material discharged from
the 2nd attrition step reaches a
flotation system, the special
reagents of which are
matched to particular
requirements of the pollutants
involved.
The flotation underflow
contains the purified material,
which is subsequently
dewatered to a residual
moisture content of about 15-
20% and can be disposed or
piled as cleaned product.
The pollutants are
concentrated in the froth
discharged during flotation.
This froth reaches the
thickener for pre-dewatering.
The thickener underflow is
brought to a moisture content
of about 20% in a dewatering
step and being discharged as
filter cake.
The pollutant concentrate is
composed out of the following
process streams:
1. Light fraction from the
gravimetric sorting (such as
wood, tar fragments, coal,
coke, etc.).
2. Overflow from the
hydrocyclone, essentially
the fines portion of the soil
with the adsorbed pollutants.
3. Flotation froth.
Fractions 2 and 3 are obtained
together as filter cake.
It has turned out that the
process can also effectively
clean the fine grain fraction.
The process, therefore, is also
able to decontaminate soils
with a high proportion of fine
grain (less than 63 microns in
diameter). Depending on the
composition of the soil and the
nature of the contamination,
the yield of decontaminated
soil is between 70% and 90%
of the untreated soil. The
residual pollutant content in
the purified soil is clearly
below the B values of the
"Dutch list."
The process water used in the
Lurgi-DECONTERRA® plant is
recycled. The input of fresh
water, therefore, is limited to
about 25 gallons/ton,
depending on feed moisture.
In order to prevent an
accumulation of contaminants,
the process water passes a
water treatment unit, where
fines as well as dissolved
compounds are precipitated
and removed from the circuit.
194
-------
Batch Scale Tests and Pilot Plant
Lurgi has investigated and
cleaned laboratory scale
samples of 50 kg of many
different contaminated soils
from coking plants, gas works
and other locations of
contaminated waste.
The knowledge gained led to
the development of the
DECONTERRA® -process and
to the construction of a pilot
plant with a throughput of
about 1 ton/hour.
The soils tested on a
laboratory scale were also
treated in the pilot plant, in
which the decontamination
results were confirmed.
Transportable Pilot Plant
195
-------
Some of the materials tested so far:
PROJECT: Town Gas Plant Site
Material Characteristics:
Silt content: 30%
All values given in ppm
Contaminants
PAH, sum (EPA)
Naphthalene
Anthracene
Pheno anthrene
Pluoro Anthrene
Pyrene
3, 4 Benzo pyrene
Hyrdocarbons
Raw Soil Clean Soil
1,150 16
16 1.6
23 <1
180 1.7
150 2
88 <1
18 <1
1,900 50
Limit
20
200
Reduction (%)
98.6
90
99
99
98.6
99
99
97.3
Clean soil recovered: 85%
PROJECT: Non-Ferrous Smelter Site
Material Characteristics:
Silt content: 28-47%
All values are in mg/kg
Contaminants Raw Soil Clean Soil
Pb
Cu
Zn
Hg
840 42
2,615 28
1,970 87
265 36
Limit
150
100
500
50
Reduction (%)
95
98.9
95.5
86
Clean soil recovered: 75-86%
PROJECT: Ammunition Plant Site /Stadtallendorf
Material Characteristics:
Silt content: 20%
Type of soil: Residue of weathered sandstone
All values are in ppm
Contaminants Raw Soil Clean Soil
PAH
Hydrocarbon
2, 4, 6 TNT
6,400 (max)
1,500 (middle) „, 0.7
Limit
1
Reduction (%)
99.9
Clean soil recovered: 79%
PROJECT: Coking Plant Site
Material Characteristics:
Silt content: 62%
Type of soil: Sandy-clayey, with some coal and coke rests
All values are in ppm, except as noted
Contaminants Raw Soil Clean Soil
PAH
Phenol (ges.)
Cyanide
Total Carbon (%)
Cu
Hg
1,030 13
1.5 0.4
8.9 0.4
5.9 1.8
16 7.2
2 <0.5
Limit
20
0.5
1.0
10
1.0
Reduction (%)
98.8
73
95.5
70
55
75
Clean soil recovered: 76%
Many other materials have been tested. So far we have not run pesticide and/or arsenic
contaminated material, but we are set up to do so.
196
-------
Commercial Experience
The commercial plants have a
capacity of 25 MTPH. The first
one started up in June of this
year. It is cleaning up a former
smelter site which is being
converted into an office park.
Its performance confirms the
pilot plant results.
Another commercial plant with
a capacity of 40 MTPH has
been in operation since June
1990. It removes and recovers
mercury from soil removed
from a former wood treating
factory; now a shopping mall.
A third commercial plant is
cleaning soil at a former coke
oven site. It is in operation
since October 1992.
Commercial plant under construction. Attritioner drum and clarifier at the right side of the picture.
197
-------
A fourth one, to clean up the
Stadtallendorf TNT, is in
fabrication.
In general these plants are
built up of transportable
modules.
Commercial plant in operation.
198
-------
Dutch List
Since the question is asked so often, a copy of the Dutch list is
reprinted, with permission. In this list
— A, B, C are indicative values.
— A —Reference category, natural background
— B —Threshold value, postulate further investigation.
— C — Anomalous value, which indicates remediation activities.
' Vorkommen in:
StoH / Konzentration
I.Metalle
Cr
Co
Ni
Cll
Zn
As
Mo
Cd
Sn
Ba
Hg
Pb
II. Anorganische Verbindungen
WlalsN)
F(gosamt)
CNtgesamt-frei)
CNfgesamt-kompl.)
S(gesamt)
Br(gesamt)
PO'(alsP)
HI. Aromatische Verbindungen
Benzol
Athylbenzol
: Toluol
Xylole
Phenole
Aromaten (gesamt)
IV. Polycyclische aromatisclie
Kohlenwasserstoffe (PAKI
Naphthalin
Anthracen
Phenanlhren
Fluoranthen
Boden (nig/kg TS)
ABC
100 250 800
20 50 300
50 100 500
50 100 500
200 500 3000
20 30 50
10 40 200
1 5 20
20 50 300
200 400 2000
0.5 2 10
50 150 600
200 400 2000
1 10 100
5 SO 500
2 20 200
20 50 300
0.05 0.5 5
0,05 5 50
0.05 3 30
0.05 5 50
0.05 1 10
0.1 7 70
0.1 5 50
0,1 10 100
0.1 10 100
0.1 10 100
Grundwasser (ji/ll
ABC
20 50 200
20 50 200
20 50 200
20 50 200
50 200 HOO
10 30 100
5 20 100
1 2.5 10
10 30 150
50 100 500
0.2 0.5 2
20 50 200
200 1000 3000
300 1200 4000
5 30 100
10 50 200
10 100 300
100 500 2000
50 200 700
0.2 1 5
0.2 20 60
0.2 15 50
0.2 20 60
0.2 15 50
1 30 10
0,2 7 30
0,1 2 10
0.12 2 10
0,02 1 5
Vorkommen in:
Stolf / Konzentration
Cryscn
Benzolnl.-iiilhrnzttn
Bcnzo(a)pyren
Bcnzo (k) fluuronlhCMi
n(c|lH)|>
-------
Subsurface Remediation Technologies
VflC
Subsufoce Aorwdiotlon Spccioliso
Efficient and Cost-Effective Programs for Soils and
Groundwater Restoration
Joseph A. Pezzullo, P.E., Terra Vac, Princeton, New Jersey, U.S.A. and Bretton E. Trowbridge, P.E., Terra Vac, Costa
Mesa, CA, U.S.A.
ABSTRACT
As the nations of the world struggle with the complexities of
cleanup of the hazardous waste which already exists and attempt
to control and manage the discharge of more wastes, they are
caughtin a dilemmabetween a plethora of regulatory guidelines
and the limitations of technology development It is difficult to
enforceregulationsonindustry if thereisno technology available
to remediate the waste.
UsuaUy.themostseriousformofhazardouswasteisthatwhich
cannot be seen; waste that is in the soils and groundwater.
The wastes, commonly in theform of petroleum hydrocarbons,
volatile organic compounds, and inorganic compounds, slowly
leach through the soils and into the groundwater where conven-
tional methods of remediation may take decades, and the costs
may become outrageous. More effective means of subsurface
remediationmaybeaccomplishedbytreatmentofthecontamina-
tion at the source and managing the migration of the contami-
nants away from the source.
Complex subsurface contamination problems require innova-
tive solutions, and fortunately, for the most part, the advances of
technology have kept pace with the regulatory environment
This paper presents three common, yet complex, cases of
subsurface contamination where both soils and groundwater
were restored by the application of innovative and cost effective
remedial measures.
INTRODUCTION
To citizens worldwide, environmental topics pose major con-
cerns. Industrializednationsbattlethesevere, polluting effects of
hazardous waste discharges while the developing nations tor-
ment with ideas on how not follow in the footsteps of their
brethren while building their own economies.
How then to manage such a task; to clean up the hazardous
wastewWch already exists andmanagemedischargeofaU future
hazardous waste?
During the recent Earth Summit in Rio de Janeiro, nations all
over the world took it upon themselves to make a cooperative
effort toward a cleaner environment Some of the time, such
"cooperative efforts" mean individual efforts and voluntary con-
straints, but most of the time "cooperative efforts" result in
regulations.
Regulationsmaybethekey.butonefactorishowwekeeppace
between regulations and technology. After all, how can nations
enforce regulations if there are no suitable and cost effective
technologies available to solve to the problem? Hazardous waste
problems are complex and they require innovative solutions.
Notwithstanding these complexities, most casesof hazardous
waste can be grouped into three general categories; petroleum
hydrocarbons, volatile organic compounds, and inorganic com-
pounds.
One way to mitigate the problems associated with hazardous
waste in surface water is to treat the waste at the source by
controlling and treating discharges. This is an obvious, healthy,
and aesthetic move toward making the environment pristine.
However, the silent killers rest beneath the ground surface, in
contaminated soils and groundwater. Contamination which en-
ters thesoileventuallyleachesintothegroundwater; groundwater
which eventually finds its way to fresh water supply wells and also
some surface waters. Subsurface contamination is a major prob-
lem, and to treat it you do the same thing as you do for surface
water. That is, treat the problem at the source and control its
migration.
This paper presents three cases where cost effective and
innovative solutions were applied to solve a problem in each of the
three categories of subsurface contamination.
These cases represent only a sampling of the many technolo-
gies which are available, nevertheless they depict three situations
where cost effective, innovative techniques of source treatment
and migration control were utilized to solve the problems of
subsurface contamination.
SUBSURFACE CONTAMINATION
Typically, the source of subsurface contamination begins in the
soils. Surface spills, leaking underground storage tanks, heap
leachingfields, and wornorruptured pipelines arejustafewways
in which soils can become contaminated.
The contamination may exist in several different phases in the
subsurface soils as pictured in Figure 1 (next page). The aqueous
phase is that which is dissolved in the soil's water saturation. If the
contaminantis volatile, the vapor phase fills the soil's air porosity
fraction. Lesser amounts are adsorbed to the soil matrix. In
addition, there also may be free phase liquid product With all
Copyright 1991 by Terra Vac, Costa Mesa. CA, USA
200
-------
Hydrocarbon Vapor
Soil
Adsorption
Moistu
Droplet
with
Dissolv.
Hydr
Residual
Liquid
Hydro-
carbon
:loating
iquid
Hydro-
:arbon
FIGURE 1: HYDROCARBONS IN THE SUBSURFACE
these fractions describing the source of soil and groundwater
contamination, itis essential thatremedial techniques address all
phases of the contamination.
PETROLEUM HYDROCARBONS
Some of the more common contaminants in the subsurface are
petroleum hydrocarbons. Petroleum production, refining, trans-
fer, and marketing operations all contribute to the oil, gas, diesel,
and jet fuel, amongst some contaminants, which are known to be
in the soils, floating on the groundwater, or migrating off some-
where in a groundwater plume. Nearly everyone knows of a case
like this, howeverwhatmany do notrealizeis thatittakes just one
liter of gasoline to render one billion liters of water non potable.
One particular case reported by Trowbridge and Malot, 1991,
involves a residential subdivision in the northwestern U.SA
where in 1987, petroleum hydrocarbons were found in an under-
lying aquifer. The subdivision is located down gradient from
several petroleum refining, pipeline, pumping, and storage facili-
ties. The discovery of liquid phase hydrocarbons directly beneath
a residential area wat, of immediate concern.
Figure 2 is a site map that shows the location of the hydrocar-
bon plume and the apparent hydrocarbon thickness contours.
The measured liquid phase hydrocarbon thickness varies from
0.06 to 0.2 meters. The unsaturated soils above the water table
were tested, but their low hydrocarbon content confirmed that
the liquid hydrocarbons had indeed migrated to the residential
area along the surface of the water table. Groundwater levels in
the area fluctuate about one meter per year.
The geology of the site is unconsolidated alluvial deposits
overlying a sandstone and shale bedrock. The alluvium is charac-
terized by discontinuous clayey silts and silty clays to a depth of
approximately 1.5 meters. The next20 meters are a
fairly homogeneous medium to course grained
sand with gravels and cobbles. The groundwater
table begins at about 10 meters, and the aquifer is
believed to have a thickness of about 10 meters.
Initial efforts to recover free floating product
included aproductpumpingsystem; however, after
several weeks of operation and obviously much
more product in the ground, the product pumps
were collectively delivering a mere four liters per
day of product. The radius of influence of the prod-
uct pumps was insignificant, and the system was
incapable of drawing the long plume of floating
hydrocarbons into the recovery wells.
In the fall of 1988, a pilot test of the innovative
vacuum extraction system was installed to evaluate
the effectiveness of the technology for removing
liquid phase hydrocarbons from the water table.
Four vacuum extractionwells were installed forthe
pilot test Design specifications for the test were
14m3/min vapor flow, and the process system in-
cluded a vapor/water separator, extractionblowerandacatalytic
oxidizer for vapor treatment Figure 3 (next page) is a process
diagram of the pilot system.
The recovery rate of the four-well pilot test was approximately
50 gallons per day, with a radius of influence of over 30 meters per
well. Over a period of four weeks 4,500 Kg of hydrocarbons, or
the equivalent of about 5,300 liters of gasoline, were removed.
The success of the pilot system led to expansion into full scale
operations. Several more wells were installed and the process
equipment was upgraded. Interestingly enough, many wells
showed no evidence of free floating product until vacuum was
applied to the wells, indicating the effectiveness of the vacuum
extraction system in capturing and vaporizing free productmuch
faster than other pumping schemes.
Figure 4 (next page) is a crossplot of typical wellhead vapor
FIGURE 2: SITE MAP WITH HYDROCARBON
PLUME
201
-------
1500SCFM
Catalytic Oxkllz«r
FIGURE 3: PILOT SYSTEM PROCESS DIAGRAM
concentrations for one well during the pilot test The plot is
indicative of the rapid vaporization and recovery of petroleum
hydrocarbons by the vacuum extraction process.
In all, the expanded vacuum extraction system recovered
approximately 87,400 liters (23,000 gallons) of hydrocarbons
over a 350-day period. Figure 5 shows the removal trend and
cumulative amount of hydrocarbons extracted. These high ex-
traction rates and cumulative removal trends support the effec-
tiveness of vacuum extraction to vaporize liquid phase hydrocar-
bons which were otherwise not removable with traditional pump-
ingtechniques.After350days,thevacuumextractionsystemwas
I,.
i
1
o
i
Q m
D
300 '
Si
^ tf, 200 •
Da
D
100 •
13 cnfl
j
D 0 1 o
(3 _ I U
m a B@
^ D D
INSET
20
D
Q
D
0 100 200 300
Run Time (days)
400
still recovering hydrocarbons ata rate of 190 to 230 liters per day.
CHLORINATED HYDROCARBONS
Another common form of subsurface contamination are vola-
tile organic compounds (VOCs). Virtually every manufacturing
process of raw materials, from high tech industries to machine
shops and dry cleaning establishments, have used some sort of
chlorinated solvents for de-greasingor cleaningpurposes. In fact,
of the 1,700 sites on the United States National Priority list (i.e.
Superfund Sites), more than 60% have VOCs as the primary
pollutant
At one Superfund Site in Michigan, U.SA, (Malmanis et al,
1989, Malmanis et al. 1990, Trowbridge and Malot, 1991) the
8000
S 6000 -
I
100 200
Run Time (days)
300
FIGURE 4: WELLHEAD VAPOR CONCENTRATION
TREND
FIGURE 5: HYDROCARBON REMOVAL TREND
facility was used as a transfer and storage plant for handling
industrial solvents. The site had 21 buried underground storage
tanks (USTs), and a variety ofVOCs werefoundin the subsurface
soils and groundwater, including trichloroethylene (TCE),
tetrachloroethylene (PCE), trichloroethane (TCA), methylene
chloride, xylenes, acetone, toluene, ethyl benzene, and 1,1,-
202
-------
dichloroethylene. Soil concentrations were as high as 1,800 mg/
kg (ppm/, and the area of contamination covered approximately
3,250 ma. The groundwater table is situated at a depth of about 7
m. The site plan is shown in Figure 6.
The U.S. EPA designated vacuum extraction as the remedial
technology to clean the soils. The cleanup criteria were for soil
samples to be less than 10 mg/kg, with no more than 15% of the
samples above 1 mg/kg total VOCs.
A vacuum extraction system similar to the schematic in Figure
7 was installed at the site. The system included 23 vacuum
extraction wells strategically placed throughout the area of the
buried tanks. The system began operations with activated carbon
for vapor treatment; however, with extraction rates as high as
2,000 kg/day, preparations were made to switch to a catalytic
oxidizer. Since catalytic oxidation of chlorinated compounds had
previously never been permitted at a Superfund Site with VOCs,
Oroundwaur Monitoring
BUM Ing
FIGURE 6: SITE PLAN
a source test was completed which demonstrated the effective
ness of the catalytic oxidizer to destroy the chlorinated hydrocar-
bons and other compounds. Figure 8 shows the results of the
source test which achieved an overall destruction rate of 99.8%.
Free floating non aqueous phase liquids (NAPLs) were also
identified at the site, but as in case 1, many wells did not contain
any free product until vacuum was applied. Nearly 0.6 meter of
free product was identified in selected locations. Once gain, the
innovative vacuum extraction remedy showed unparalleled per-
formance for removing free floating contaminants from the
groundwater table, and Figure 9 (next page) illustrates that the
vacuum extraction system completely vaporized the free floating
product within a period of 40 days.
In all, over 20,000 kg of VOCs were removed form the soils
within two years. The soils have been declared clean by EPA to 0.1
mg/kg, yet groundwater treatment continues. A separate
groundwater treatment system has been modified to allow Dual
CATOX EFFICIENCY FOR
CHLORINATED HYDROCARBONS
COMPONENT
Acetone
Methylene Chloride
TCA
Benzene
TCE
Toluene
PCE
Xylene
Other
Total
INLET
(ug/l)
7.7
0.8
8.3
0.1
21
18
54
25
1M
319
OUTLET
(ug/l)
ND
ND
ND
ND
ND
ND
0.6
ND
ND
0.6
PERCENT
REMOVAL
___
..
^^
--.
99.8
FIGURE 7: VACUUM EXTRACTION SYSTEM
SCHEMATIC
FIGURE 8: SOURCE TEST RESULTS
Extraction™, or the simultaneous recovery of vapors and
groundwater fromthesame wells. The Dual Extraction™ system
significantly increased VOC recovery rates from the saturated
zone, and impact of applied vacuum in the wells concurrent with
groundwater pumpinggreatiy accelerated vapor phase partition-
ing of VOCs. Figure 10 (next page) is a schematic of the Dual
Extraction™ system.
To further accelerate in the groundwater cleanup, an innova-
tive nitrogen sparging system was installed in October 1991.
Known as SpargeVAC™, this in-situ water treatment functions
just like an in-ground air stripper. As fresh air or nitrogen is
injected into the saturated zone, the air rises through the
groundwater. The dissolved, adsorbed, and liquid phase VOCs
are partitioned into the vapor phase, rise to the unsaturated zone
(i.e. vadose zone), and are recovered by the vacuum extraction
203
-------
process. Figure 11 represents the SpargeVAC™ process. Tie
sparge gas used at this Superfund Site was nitrogen, as the high
iron concentrations in the groundwater raised concerns regard-
ing the formation of ferric oxide in the pore space of the aquifer
if regular compressed air was used.
The sparging system resulted in a 21-fold increase in extracted
10 20 30
Run Time (Days)
40
FIGURE 9: NAPLTHICKNESS VS. VES RUN TIME
toluene concentrations, and 300% increase in the PCE and TCE
concentrationsbeing extracted in thevaporphasebythevacuum
system.TheEPA'sgroundwaterextractionsystemhad operated
for Syears at200 m3 per day and itwas only effective in reducing
the groundwater concentrations from an initial level of about 19
ppmtoaboutSppm.
Using the SpargeVAC™ technology, the groundwater concen-
trations were reduced 93% to less than 150 ppb within four
months.There was no comparison between the effectiveness nor
the costs of conventional groundwater pumping and the superior
DUAL EXTRACTION™
FIGURE 11: VACUUM EXTRACTION/AIR
SPARGING
performance and lower costs noted with the innovative vacuum
extraction, DualExtraction™ andSpargVAC™ technologies. The
EPAhad spent more money studying the site than the innovative
remedial technologies cost to clean it
INORGANIC COMPOUNDS
The generation and release of inorganic compounds into the
soils and groundwater are yet more cases of hazardous waste
contamination which have fallen under intense scrutiny by regu-
latory agencies worldwide. Industries such as mineral explora-
tion and metal working industries are vital contributors to an
economy, yet they are also major causes of contaminated water-
ways and estuaries by heavy metals and other compounds.
However, inorganic compounds undergo several different
geochemical and biological interactions in the subsurface, and
many situations which might appear disastrous at first can be
controlled and mitigated by innovative techniques involving
chemical oxidation, natural attenuation, and en-
hanced biodegradation.
Oneinorganiccompound, cyanide, iswidelyused
in theminingindustry to leachgold silver and other
ores from processed rock. It is well documented
that cyanide undergoes numerous reactions in the
subsurface by a variety of geochemical and biologi-
cal mechanisms. Rouse and Pyrih, 1991 describe
several different physio-biochemical mechanisms
in the subsurface in which cyanide may participate.
In 1991, routine ground and surface water moni-
toring activities at a heap leaching mine facility
FIGURE 10: DUAL EXTRACTION™ REMEDIATION discovered cyanide contamination in the ground
204
-------
and surface water (Rouse and Gochnour, 1992). A schematic
- diagram of the site is depicted in Figure 12.
Although the leach pad was constructed with triple liners,
apparently a silicone seal in one of the drain pipes failed and
allowed the cyanide-bearing leachate solution to migrate out of
thepadandinto theunderlyingpadfillmaterialandsoils beneath.
Thecyarudesolutionsubsequentiymovedalongashallowburied
alluvial channel and was detected in seep springs near a monitor-
ing well. The cyanide seepage was found to contain approxi-
Pump-back trench, , H, O, Injection trench
FIGURE 12: SITE MAP
mately 80 mg/1 CN WAD (weak acid dissociable). There were
also elevated quantities of copper, gold, silver, and zinc.
The mine owner responded immediately, and a series of
trenches and ponds were constructed to capture and control
some of the migration of the cyanide and to treat the contami-
nated media. Treatment of the seepage was accomplished by
adding hydrogen peroxide to oxidize cyanide, and a recirculating
sprinkler system which enhanced the ultraviolet decomposition
of cyanide in the water.
Upon the addition of hydrogen peroxide, the water in the
trenches turned green as the copper cyanide complexes de-
graded and a copper precipitate was formed. In addition, biologi-
cal studies on the soils revealed that they contained indigenous
microorganisms which were capable of biologically degrading
the residual cyanide. The addition of phosphate fertilizer en-
hanced the process, and bacteriological counts confirmed that
the biodegradation of residual cyanide was successful.
The result was a rapid decline in cyanide concentrations
in the seepwater and soils in response to the containment,
chemical oxidation, and biodegradation processes. Total
cyanide concentrations were reduced to < 0.1 mg/1 within
one month.
CONCLUSION
The case studies presented herein are representative of
only some of the many technologies which are available to
remediate hazardous waste in the subsurface and restore
the environment Environmental problems involving sub-
surface contamination are complex; however, innovative
technologies do exist to control, mitigate and cleanup
subsurface contamination.
Moreover, an aggressive approach toward cleanup of
thesourcesofcontaminationisnearly always the mostcost
effective.
ACKNOWLEDGMENTS
The authors would like to thank SteveThompson for his
efforts in preparing the graphics for this paper.
REFERENCES
Malmanis, E.; Fuerst, D.W.; and Piniewski, RJ.; 1989,
"Superfund Site Soil Remediation Using Large-Scale
Vacuum Extraction," Proceedings HMCRI Conference,
New Orleans, U.S A, pp. 538-541.
Malmanis, E.; McClenahan, R., 1990, "Full Scale Vacuum
Extraction Remediation—Michigan Superfund Site," Air
and Waste Management Association, 83rd Annual Meet-
ing and Exhibition, Pittsburgh, PA, June 24-29,1990.
Trowbridge,B.E.,andMalot,JJ.,1991,"SoURemediation
and Free Product Removal Using In-Situ Vacuum Extrac-
tion with Catalytic Oxidation," National Groundwater As-
sociation, Dublin, Ohio, U.SA
Rouse, J.V., and Phrih, R.Z., 1991, "Geochemical Attenuation
and Natural Biodegradation of Cyanide Compounds in the Sub-
surface,"
Rouse, J.V., and Gochnour, P., "Remediation of Soil and Water
Contaminated By Cyanide Using Peroxide and Biodegradation,"
Proceedings Randol Gold Forum '92, Vancouver, British Colum-
bia, Canada, March 25-27,1992.
205
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RADIOLYTIC REMEDIATION OF A TCE GROUND SPELL
USING AN ELECTRON ACCELERATOR*
S.M. Matthews, A.J. Boegel, J.A. Loftis and R.A. Caufield,
Lawrence Livermore National Laboratory
P.O. Box 808, Mail Code L-629, Livermore, CA 95550 USA
ABSTRACT
Radiolytic decomposition of chlorinated hydrocarbons and other toxic compounds has
been experimentally measured using ionizing radiation produced by electron accelerator and
nuclear isotope sources. Decomposition products have been identified. A portable,
commercially available electron accelerator was set up at a Superfund site where vapor extraction
wells were removing trichloroethylene (TCE) from a spiU into the unsaturated soil. The
extraction vapor was passed through the accelerator beam to decompose the TCE. On site
radiolytic decomposition of TCE vapor using an accelerator is shown to be significantly less
expensive than filtration of TCE vapor using activated charcoal.
KEY WORDS
Ionizing radiation, bremsstrahlung, electron beam, chlorinated hydrocarbons, Superfund
site, radiolytic decomposition, VOC, TCE.
INTRODUCTION
Toxic compounds and hazardous materials can be radiolytically decomposed when
exposed to ionizing radiation. We have experimentally demonstrated this effect on samples of
volatile organic compounds (VOCs) and high explosives dissolved in groundwater and on
polychlorinated biphenyls (PCBs) dissolved in transformer oil. These results have been reported
elsewhere. This report describes results of a trial demonstration at a Superfund site where an
electron accelerator was used to radiolytically decompose trichloroethylene (TCE) vapor.
FIELD DEMONSTRATION
Site-300 is on the National Priority List (NPL) due to a TCE ground spill that permeated
the unsaturated subsurface soil. This Superfund site was in remediation process using vacuum
extraction wells that removed subsurface air enriched with TCE vapor. The air was passed
through an activated charcoal filter to remove TCE before release to the atmosphere. An
industrially available, portable, 2 MeV electron accelerator with a beam power of 1 kW was
brought to the site and connected into the remediation system upstream of the activated charcoal
filter so that all vapor extracted from the soil was passed through the electron beam before
*Work performed under the auspices of the U.S. Department of Energy, DOE Contract Nos.
W-7405-ENG-48.1
206
-------
reaching the filter. Electric power to the accelerator was provided by a 10 kW input.
Retrofitting the accelerator and related equipment into the Site-300 system required one week.
Vapor samples upstream and downstream of the electron accelerator were analyzed and
compared with the beam power set at six different levels. The TCE concentration in the vapor
was monitored using a field portable gas chromatograph (GC). Vapor samples were also
collected in steel spheres and sent to four independent chemical laboratories for analysis of TCE
content and reaction products. Two of these labs were EPA approved to perform a TO-14
chemical analysis scan for forty different VOCs.
The hardware that was installed at the site to radiolytically decompose the TCE vapor
is schematically shown in Fig. 1.
Electron accelerator
Electron beam
Inflow plpea
Exhauat plpea
Expoaure plenum
20 fe»t
Fig. 1. Schematic of field hardware setup to radiolytically decompose TCE
vapor from vacuum extraction wells.
The exposure plenum (5) was fabricated from sheet steel as a cylindrical chamber with
a 45° conical section at one end. The plenum diameter was 213 cm with an overall length of
610 cm. This length was chosen because it is approximately the range of a 2 MeV electron
through atmospheric air. The plenum structure was placed within a 610 cm deep hole with an
oversized diameter to allow clearance between the sides of the plenum and hole. The apex of
the plenum conical section pointed vertically upwards giving an appearance similar to a missile
in an underground silo. The electron accelerator was placed on the ground surface with the
beam pointed vertically downward, entering the plenum through a foil window placed at the
conical apex. A small shielded structure made from cement blocks was constructed about the
accelerator. This arrangement minimized background radiation exposure to personnel while the
accelerator was operating. Background exposure outside the shielded structure was 5
micrograys/hr with beam power at 40 watts. The accelerator was operated by two workers
located at a control module placed inside a truck approximately 18 meters away. The control
207
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module was connected to the accelerator by a cable.
The TCE enriched vapor was pumped from the wells by a vacuum extraction pump that
exhausted the vapor at atmospheric pressure. Plastic PVC pipe was connected to the vacuum
pump exhaust and brought the vapor to the two inflow pipes (3) where it entered the plenum.
The entering vapor was deposited at the chamber floor at atmospheric pressure and moved
vertically upward toward the two exhaust pipes (4) at the top of the plenum where the vapor
exited. The vapor was exposed to the electron beam (2) during its passage through the plenum.
The vapor exited the plenum and was routed through PVC pipes to the activated charcoal filter.
Vapor circulation through the system was provided by the vacuum extraction pump.
Maximum electron beam power was restricted to 400 watts because the accelerator was
originally designed as an industrial x-ray unit and had to be modified for this demonstration.
The vacuum extraction pump provided vapor circulation through the system at a fixed rate of
270 CFM (127 1/s). Vapor travel time through the plenum was approximately 2 min. Monte
carlo calculations of the electron beam transport through the plenum indicated, that at this
circulation rate, the vapor received a dose of 0.9 kGy with the beam power set at 400 watts.
The electron beam power was increased from zero to 400 watts in 80 watt increments to provide
data at six power levels. The accelerator ran for one hour at each power level while vapor
circulated through the system so that equilibrium could be established before gas samples were
collected.
The TCE concentration in the unirradiated vapor was measured to be 60 ppmv. The
TCE concentration in the irradiated vapor is plotted as a function of accelerator beam power in
Fig. 2.
04-
0
50 100 150 200 250 300 350 400 450
Electron Beam Power - Watts
Fig. 2. TCE concentration in irradiated soil extraction vapor as a function of
electron beam power.
208
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These TCE concentration data were gathered using the on-site portable GC and are in
good agreement with the measurements made on the collected vapor samples by the off-site
analytical laboratories. These data show that the TCE concentration in the vapor extracted from
the soil is reduced from 50 ppmv to less than 1 ppmv when the electron beam is operating at
the 400 watt power level. Data obtained from off-site analysis of the collected vapor samples
are shown in Fig.: 3. where the concentrations of organic reaction products are plotted
logarithmically as a function of exposure dose.
Q.
Q.
1.000
0.100
c
_o
*J£
2
"g 0.010-
o
c
o
o
0.001
Trfm«thylb«nz«n« Q
PCE
Chloroform — •
Carbon Titrachloridc
DlchtorerMthano
-10 10 20 50 70
Radiation Dose — kRads
90
Fig. 3. Concentration of organic reaction products in irradiated soil vapor as a
function of exposure dose.
The 90 kRad (0.9 kGy) dose shown in Fig. 3 corresponds to 400 watt beam power. The
figure shows that the TCE concentration is reduced to approximately 0.2 ppmv. A small
concentration of perchloroethylene (PCE), initially present in the vapor at 0.1 ppmv, was
reduced to 0.002 ppmv while carbon tetrachloride, initially at a concentration of 0.01 ppmv was
reduced by only 10%. Three VOCs were produced in low concentration from the TCE reaction
products. These were chloromethane and dichloromethane which were increased to a maximum
concentration of 0.008 ppmv and 0.020 ppmv respectively and chloroform which was initially
present in the vapor at a concentration of 0.01 ppmv and increased to 0.1 ppmv by exposure to
the electron beam. Trimethylbenzene was produced in the vapor at a maximum concentration
of 0.4 ppmv when irradiated to a dose of 0.35 kGy but decreased in concentration with increased
dose. It is suspected that the trimethylbenzene was formed from trace amounts of diesel fuel
that accompanied the TCE spill. Small concentrations of acetone at less than 0.1 ppmv were
also produced and then partially destroyed with increasing dose. It is not understood how the
acetone was formed.
The net concentration of organic reaction products shown in Fig. 3 amount to much less
that the initial 50 ppmv TCE concentration present in the unirradiated vapor. Most of the TCE
209
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decomposition products are suspected to be inorganic chloride and carbon dioxide. Indications
of hydrochloric acid corrosion in the plenum were present. Unfortunately, the collected gas
samples could not be analyzed for hydrochloric acid because of chemical reaction of the acid
with the walls of the stainless steel collection spheres. The increase in carbon dioxide was
calculated to be only a small fraction of the normal concentration of CO2 in air and therefore
was not measured. An analysis of other inorganic compounds in the irradiated vapor found no
oxides of nitrogen or ozone. Only oxygen, nitrogen, argon, carbon dioxide and water vapor
were found at nominal concentrations.
This demonstration was terminated after six weeks at the site because the electron
accelerator, which was borrowed from another program, had to be returned.
ECONOMICS
The experience gained with the Site-300 demonstration provided information on hardware
requirements, fabrication costs, retrofit installation problems, performance parameters, and
operating expenses. We were able to estimate the economic performance of an electron beam
remediation system and compare costs with remediation using activated charcoal filtration. Our
estimates were based upon a system sized to the TCE spill at the Savannah River Site (SRS)
where vacuum extraction wells withdraw subsoil vapor at a TCE concentration of 500 ppmv and
extraction rate of 500 CFM (2361/s). If the extraction wells operate with an average up-time
of 80%, then 17.5 metric tons of TCE would be removed annually.
A portable, 2 MeV electron accelerator with a 3 kW beam power can be coupled with
an exposure plenum similar to that used at the Site-300 demonstration. This system could
operate with an annual up-time of 80% and provide a radiation dose of 3.6 kGy to a TCE vapor
stream flowing at a rate of 500 CFM. This dose is sufficient to reduce TCE concentration from
500 ppmv to below 0.2 ppmv. Trace organic reaction products formed in the vapor are also
expected at concentrations below this level. The hardware required to construct this type of
system consists of the accelerator, exposure plenum, and shielded structure. Operating expenses
consist of salaries for two employees working 24 hours per day, annual equipment maintenance
at 10% of capitalization, electricity costs, and miscellaneous. The estimated capital costs and
annual operating expenses are summarized in Table 1.
These data indicate that the capital expenditure for an electron beam remediation system
is approximately $975,000 with an annual operating expense of approximately $465,000.
210
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Table 1. Costs for electron beam remediation system.
TCE vapor concentration - 500 ppmv.
Vapor flow rate - 500 CFM (236 1/s)
Capital Equipment
3 kW electron accelerator
Exposure plenum
Shielded facility
Retrofit installation
Miscellaneous
TOTAL CAPITAL COST
Annual Operation
Labor - two workers 24 hours per day
Maintenance at 10% capitalization
Electricity at $0.09 per kWH
Miscellaneous
TOTAL OPERATING EXPENSE
Capital Costs
$750 K
75
25
50
75
$975 K
Annual Operating Expense
$300 K
98
19
50
$467 K
The TCE could be removed from the vapor using activated charcoal filters.
Approximately 623 metric tons of activated charcoal would be needed annually to remove 17.5
metric tons of TCE from the vapor. This estimate assumes that the charcoal is recycled twice
before disposal. The TCE concentration in the filtered vapor would be 1 ppmv which is higher
than with the accelerator system. The cost for activated charcoal and disposal when loaded with
TCE is estimated at $12.50 per kg. The annual charcoal cost for the system is $7.78 million
or more than an order of magnitude higher than the annual operating cost of the accelerator
remediation system.
REFERENCE
Matthews, S.M., Boegel, A.J., et.al., (1991), High-Energy Irradiation of Chlorinated
Hydrocarbons. ANS Topical Conference MARC-H, Kona.
211
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Rethinking the hydraulic cage concept for hazardous
waste disposal facilities and mitigation of contaminated
sites1
Charles Voss
Associate, Colder Associates Inc., Redmond, Washington, USA
Abstract
In comparison with conventional hazardous waste disposal facilities, a hydraulic cage facility
relies on a zone of increased hydraulic conductivity around the control region to redirect
groundwater flow around the disposed waste. Waste containment is achieved by decreasing
the hydraulic gradient through the disposal facility. This approach is potentially more reliable
than conventional engineered barriers, such as a clay layer, because the consequence of a
breach in a low conductivity barrier is much greater than a hydraulic cage.
This paper discusses a series of analyses that were performed to investigate the performance
of a hydraulic cage in a number of rock types. Three different methods for constructing a
hydraulic cage are considered. The percentage of the groundwater a cage can divert around
a disposal facility is very sensitive to the contrast between the hydraulic conductivity of the
cage and the conductivity of the surrounding rock mass. The greater the contrast, the better
the performance. The analyses demonstrate that cages constructed using surface-based
methods can successfully improve the performance of a waste disposal site but are inferior to
underground construction techniques in most rock types. Surface-based methods are most
appropriate in rocks having a low hydraulic conductivity.
1 Introduction
A "hydraulic cage" is an engineered structure that short-circuits groundwater flow within a
site by providing a flow path with much lower resistance to flow than the natural system.
The groundwater is redirected around a central region, isolating the enclosed zone from the
regional groundwater flow system.
The hydraulic cage concept has potential application as part of waste disposal and
1 This work was supported by the U.S. Department of Energy under contract number 87-
3497.
212
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contaminated site remediation. In both instances, movement of hazardous substances
through a saturated zone takes place by advection processes. Advection, or groundwater
flow, is governed by the hydraulic conductivity of the medium (rock or soil) and the pressure
gradient over the site. The relationship is defined by the simple equation
Q=KiA
where Q is the volumetric flow rate, K is the hydraulic conductivity of the medium, i is the
gradient, and A is the cross-sectional area of flow. In order to reduce the movement of
materials either from a disposal site or a contaminated area either the conductivity or the
gradient must be reduced.
Conventional engineering methods typically rely on low conductivity barriers such as grout
or bentonite slurry walls. The difficulty with this approach is ensuring low hydraulic
conductivity for all possible pathways through the area over long-time periods. A hydraulic
cage produces a low gradient within the cage boundaries creating a stagnant groundwater
flow zone. The head (pressure) in the cage will be approximately equal to the mean value of
the heads at the upstream and downstream portions of the cage. As a result, the water in
the cage adjacent to the upstream portion will be lower than the site and water will drain
into the cage. The opposite is true at the downstream part of the cage where the water will
be discharged back into the surrounding medium. Without the pressure gradient,
contaminant transport within the cage will be dominated by diffusion, a very slow process.
The original concept of the hydraulic cage originated in the early 1980's in the Swedish High-
Level Nuclear Waste Program (SKB, Svensk Karnbranslehantering AB) (Figure 1). The nuclear
waste is stored in an array of inclined boreholes within a central storage chamber. The
chamber is surrounded by an excavated slot containing compacted bentonite and sand to seal
any fractures and provide a low conductivity barrier to flow and transport. Outside the
bentonite-sand barrier is the hydraulic cage consisting of a series of tunnel and boreholes that
reduce the gradient within the storage chamber by short-circuiting the groundwater flow
around the repository. The WP-Cave design employs a redundant barrier approach for
reducing the potential for groundwater flow and transport by providing a conventional
engineered barrier to reduce the hydraulic conductivity and a hydraulic cage to reduce the
pressure gradient.
The approach was eventually abandoned for high-level radioactive waste disposal
applications because the heat produced by the decaying waste would create thermal
gradients inside the hydraulic cage. The resulting groundwater flux would potentially negate
the isolating capability of the hydraulic cage. The concept is still attractive for other types of
waste disposal facilities that do not generate heat. A hydraulic cage could also be used to
enhance the performance of some in situ remediation technologies such as microbial
213
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Figure 1. Original WP-Core Concept
,-Tunnel
Waste
Emplacement
Boreholes
Bentonite
Boreholes
degradation by increasing the resident time of the contaminant plume.
Some of the additional advantages provided by the hydraulic cage include:
« The reliability of a hydraulic cage should be greater than a low permeability
barrier. The consequence of a breach in a traditional, low permeability barrier
is potentially more significant than a partial plugging of the hydraulic cage.
• A more favorable environment for engineered barriers such as waste canisters
and buffer materials.
• The cage could be used for dewatering of the waste containment facility during
construction, waste emplacement, and backfilling of the facility.
• The behavior of a hydraulic cage can be measured directly and with more
214
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confidence than low hydraulic conductivity barriers.
This paper discusses a series of analyses that were performed to investigate the performance
of a hydraulic cage in a number of rock types. Three different methods for constructing a
hydraulic cage are considered. Section 2 reviews earlier analyses that were performed to
evaluate the performance of the WP-Cave design. Section 3 presents two alternative
approaches for constructing a hydraulic cage using surface-based methods. The performance
of the alternative cage designs is evaluated in Section 4. Section 5 discusses additional
applications of the hydraulic cage concept in waste disposal facilities.
2 WP-Cave Performance
Earlier analyses of the WP-Cave design for nuclear waste disposal were performed by Strack
(1985), and Axelsson and Olsson (1985). Two- and three-dimensional groundwater flow
models were developed to assess the relative contribution of the two barriers (bentonite-sand
and hydraulic cage) and the sensitivity of system performance to various design assumptions
such as the number of boreholes in the cage and the thickness of the bentonite-sand barrier.
The hydrologic conditions at the site were assumed to be homogeneous and isotropic. A
relatively low hydraulic conductivity was assigned to the site based on measurements in
crystalline rock (the candidate repository sites in Sweden are located in crystalline rocks).
hydraulic cage was assumed to have a diameter of 150 m and, in the three-dimensional
model, a height of 300 m.
The
Several borehole spacing designs were considered. The minimum spacing considered was
less than 2 m with a maximum of 23.5 m. The hydraulic head in the tunnels connecting the
borehole drains was assumed to be constant (i.e., there is no resistance to flow inside the
cage).
The contributions of the hydraulic cage and the bentonite barriers to controlling groundwater
flow were assessed separately. The results of the hydraulic cage model were as follows:
• The percentage of the groundwater flow that passes through the zone within
the hydraulic cage is reduced by 70 to 99% depending on the borehole spacing.
The closer the spacing the better the performance.
• Cage performance decreases as the resistance to flow within the cage
(hydraulic conductivity) increases. Plugging of boreholes or backfilled tunnels
would reduce the amount of water diverted by the cage.
• The effectiveness of a hydraulic cage will vary depending on the site
conditions. A hydraulic cage will provide a more effective barrier in low
215
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conductivity sites.
The numerical model of the bentonite-sand barrier assumed a barrier radius of 50 m.
Variables in the analyses included the thickness and hydraulic conductivity of the barrier.
Barrier thicknesses of 1 m and 5 m were modelled with hydraulic conductivities varying by
one order of magnitude. The results are summarized in Table 1.
Table 1. Results of the Bentonite-Sand Barrier Analysis
Thickness (m)
5
5
1
Kbuife/Ktock
0.1
0.01
0.01
% Passing Barrier
63
12
52
The analyses demonstrate that the percentage of groundwater flow that passes through the
interior of the bentonite-sand barrier is sensitive to the hydraulic conductivity contrast
between the barrier and the host medium. An order of magnitude decrease in the Kb^^/K.^
ratio improves the performance by a factor of 5. The thicker barriers would be required in
low conductivity rock (e.g. crystalline rock containing few fractures) because of the low
conductivity contrast that can be achieved. The barriers would be more effective for sites
with relatively high hydraulic conductivities where the contrast would be greater.
The relative contributions of the hydraulic cage and bentonite-sand barriers depends on their
conductivity contrast with the site and the efficiency of the hydraulic cage. The contribution
of the bentonite-sand barrier would be minimal in a crystalline site with a relatively low
hydraulic conductivity (10"' to 10"12 m/s) and a cage with 3 m borehole spacing. As the
borehole spacing increases, less water is diverted by the cage and the contribution of the
barrier increases significantly. The performance of the two barriers will vary significantly
depending on site conditions. For sites with higher conductivities, such as sandstones or
fractured systems, the isolation capability of the bentonite-sand barrier would be similar or
better than the hydraulic cage.
Alternative Methods for Constructing a Hydraulic Cage
The earlier analyses summarized above demonstrated that the WP-Cave design is capable of
isolating disposal facilities from the groundwater flow field. The analyses were limited to
crystalline sites and assumed the connectivity of the cage to be ideal (i.e., there was no
resistance to flow). This section discusses two alternative methods for constructing a
hydraulic cage: hydraulic fracturing and blast fragmentation. The designs employ vertical
boreholes, similar to the WP-Cave concept, but rely on surface-based methods for
216
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hydraulically connecting the boreholes. The alternative approaches are intended as possible
means for enhancing clean-up activities at contaminated sites or as part of waste disposal
facilities where the original design may be prohibitively expensive.
Blast Fragmentation
The effectiveness of the hydraulic cage relies on developing a highly conductive and
continuous region within the rock mass. The WP-Cave design employs a series of tunnels to
connect the drainage holes within the cage and provide a low resistance pathway for
diverting the groundwater flow. An alternative method for connecting the boreholes would
be to fragment the rock between the boreholes by detonating explosives in the boreholes.
The feasibility of successfully constructing a network of interconnected boreholes using
explosives depends on several factors:
• The ability to fragment the rock over considerable distances.
• The magnitude and direction of the in situ stresses at the site.
The ability to create and propagate fractures with explosives decreases as the distance to a
free face or relief surface increases. For the case under consideration, the lithostatic and
tectonic stresses will tend to increase with depth with a corresponding increase in the rock
mass strength. In general, blast fragmentation zones having high hydraulic conductivities
will be difficult to construct at depths below 100 m.
The size and shape of fragmentation zones will also be influenced by the rock quality.
Fractures propagated during a blast will tend to terminate when they intersect existing
discontinuities such as joints or bedding planes. The impact of such features will depend on
their orientation and frequency. Vertical discontinuities oriented perpendicular to the
direction between adjacent boreholes would limit the extent of the blast induced fractures.
The impact of discontinuities will be less important in sites where the mean spacing of
discontinuities is greater than the distance between boreholes.
The in situ stress state will also influence the shape of the fragmentation field. In highly
anisotropic stress fields, fractures tend to propagate preferentially in the direction parallel to
the maximum principal stress. Notched boreholes or shaped charges could be used to focus
the energy between boreholes or the spacing between boreholes parallel to the minimum
principal stress could be decreased.
In addition to a well connected set of fractures, the hydraulic conductivity of the network
must be significantly greater than the surrounding rock mass in order to be an effective cage.
The conductivity of a blast fracture will depend on the shear dilation that occurs and the
intact strength of the rock. Dilation resulting from the dislocation of the fracture surface
217
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causes the conductivity of the fracture to increase. This effect is less pronounced in weaker
rocks where crushing of asperities would reduce the dilation of the fracture.
Hydraulic Fracturing
Hydraulic fracturing has been used extensively in the petroleum industry for improving
production in oil and gas reservoirs. A segment of the borehole containing the formation is
isolated with inflatable packers and the zone is pressured until the stresses exceed the
strength of the surrounding rock. The resulting fracture is propagated by pumping
additional fluid into the region. The fracture can be propped open to increase its aperture
(and, therefore, the conductivity) by including sand, bauxite, or ceramic particles in the
pressurizing fluid.
The use of hydraulic fracturing for constructing a hydraulic cage is limited by many of the
same constraints as blasting. Existing discontinuities will tend to limit the distance a
hydraulic fracture can be propagated and the significance of these features will depend on
fracture orientation and frequency.
The in situ stress field has a large influence on the orientation of the induced fracture plane.
Technology is available for controlling the initial geometry of hydraulic fractures although the
fracture will tend to realign parallel to the maximum principal stress as it propagates.
Nevertheless, hydraulic fracturing experts from the petroleum industry estimate that existing
hydraulic fracturing techniques could reliable connect boreholes 5 m apart even in sites with
high deviatoric stresses.
Performance of Alternative Designs
In order to consider the performance of hydraulic fracture and blast fragmentation cages,
additional analyses were performed. Four different rock types were considered based on
conditions at a number of DOE sites. A probabilistic approach was used in order to account
for the uncertainty in the site conditions and the hydraulic properties of the cages. The
assessment consisted of the following:
1. Two-dimensional finite element analyses to develop a response surface
describing the relationship between the cage performance and the hydraulic
conductivity of the cage and rock mass.
2. A literature review to develop probability distribution functions for the
hydraulic properties at different sites.
3. A probabilistic analysis of cage performance using the Monte Carlo method
and the results from steps 1 and 2.
218
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This approach reduced the number of numerical models required and provided an estimate
of the range in performance that can be expected.
Numerical Analysis
A two-dimensional finite element flow model was used to evaluate the relationship between
cage performance and the hydraulic conductivity contrast between the cage and the rock
mass. A two-dimensional model was chosen based on the results of Strack (1985) who
demonstrated that two-dimensional and three-dimensional models give very similar results
especially when the groundwater flow is assumed to be horizontal (perpendicular to the
cage).
The conceptual model assumed a cage diameter of 125 m with a uniform hydraulic
conductivity. The model did not include other types of barriers. The hydraulic conductivity
of the site was assumed to be 10ru m/s with a horizontal hydraulic gradient equal to 0.002.
The response surface was constructed by substituting a range of hydraulic conductivity values
for the cage and monitoring the amount of water diverted by the cage. The greater the
amount of water diverted by the cage, the better its performance. Cage performance Pa is
given by
cage
where CL,^ is the flow through the interior of the cage and Q^ is the flow through the same
region if the cage is not present. The range of hydraulic conductivity values for the cage was
10.]2 to 10., m/s. The results of the analyses are summarized in Figure 2.
The results illustrate that the amount of groundwater passing through the cage is markedly
reduced as the conductivity contrast between the cage and rock mass is increased. An order
of magnitude difference reduces the flow through the cage by only 15% while the
corresponding reduction for a cage with a two order of magnitude difference is more than
50%. The rate of change in performance slows considerably with additional increases in the
conductivity contrast The analyses by Strack (1985), and Axelsson and Olsson (1983),
assumed the head was equal at all points within the cage (i.e., the cage offered no resistance
to flow). Their results correspond to K^ values > 104 m/s.
219
-------
100%
90%
80%
70%
Hydraulic Cage QQO^
Performance
Index P 50%
40%
30%
20%
10%
0%
site
Based on Continuum
Simulation with K roct<
10'12 m/s
Rtted Polynomial
Simulation Result
10'12 10'11 ID'10 10'9 10'8 10'7
10"'
Hydraulic Conductivity of Hydraulic Cage (m/s)
'cage
Figure 2. Results from 2-D Model of Hydraulic Cage
A simple relationship between cage performance and the ratio of conductivities
was developed from a regression analysis of the results. The expression is given by:
Values for constants c, through cs are provided in Table 2. The parameter R is the ratio of
conductivities and is defined as:
220
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Table 2. Constants for Pcage Relationship.
Constant
cl
c2
c3
c4
c5
c6
Fitted Value from
Regression Analysis
6.94
-0.514
0.0176
-42.52
-14.32
8.873
The equation for Page was used to evaluate the performance of hydraulic cages in a range of
rock types. Four rock types, limestone, sandstone, basalt, and weathered limestone, were
chosen based on literature reviews of documents describing the site conditions at several
Department of Energy (DOE) defense sites. The dependent variable K,ite was estimated from
DOE site documents and conversations with hydrogeologists familiar with the areas. Because
of the uncertainty related to these estimates, the parameter was represented by a probability
distribution function that reflects the uncertainty about the expected value. Triangular
distribution functions were assumed. The minimum, maximum and expected values for K^
are listed in Table 3.
The hydraulic conductivity of a cage was assumed to be a multiple of the site conductivity.
The increase varies according to the rock type and construction method. In general, fracture
dilation in hard rocks, e.g., basalt, is greater than in sandstones or other soft rock. Therefore,
the conductivity of a hydraulic cage in the basalt site was assigned a higher range of values
than the limestone and sandstone rock types. The expected increase in conductivity for blast
fragmentation cages was assumed to be greater than hydraulic fracture cages because of the
greater number of fractures involved. The probability distributions for K^g. are also
triangular. Table 4 contains the minimum, expected, and maximum values for calculating the
cage conductivity.
221
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Table 3. K,te Values for Monte Carlo Analysis
Rock Type
Limestone
Sandstone
Basalt
Weathered
Limestone
K*. (nVs)
minimum
5 x 1010
10*
10-io
to-7
expected
3.2x10*
10s
10-9
10s
maximum
SxlO"7
lo-4
lO"7
lo-4
Table 4. Distributions for K^ multiplication factor.
Rock Type
Limestone
Sandstone
Basalt
Weathered
Limestone
Blast Fragmentation
(x'sK.J
min
75
10
75
75
exp
750
100
1000
500
max
1000
1000
105
5000
Hydraulic Fracture
(x's K,, J
min
10
10
10
10
exp
100
50
250
100
max
1000
500
5000
750
Monte Carlo Analysis
The relative performance of hydraulic fracture and blast fragmentation cages in the four rock
types was assessed using the polynomial relationship for Pagt. Values for R were calculated
by sampling from the distributions for K,,te and K^. The Monte Carlo method was used to
sample from the distributions and the process was repeated 1000 times to obtain a probability
distribution of cage performance for each of the rock types.
The results of the analysis are summarized in Figure 3. Each of the box plots represents the
results for a different combination of cage type and rock type. The box represents the .25 to
.75 percentile values for Pagt and the horizontal line the .50 percentile value. The vertical lines
222
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Qcage /Qsite
Blast Frac Blast Frac Blast Frac Blast Frac
Limestone Sandstone Basalt Weathered
Limestone
Figure 3. Results of Monte Carlo Analysis of
Hydraulic Cage Performance
extending above and below the box represent the range of values between the .05 and .95
percentile values.
The magnitude and range of the hydraulic cage performance results varies considerably
depending on the rock type and construction method. The blast fragmentation cage
performed significantly better than the hydraulic fracture cage due to the higher conductivity
that could be developed. The difference in performance is less noticeable in the basalt rock
because of the greater contrast in conductivities. The results show that there is a significant
probability that a hydraulic fracture cage would divert a relatively small percentage of the
groundwater flow in most of the rock types. The performance of the blast fragmentation
cages is much better and fairly consistent within the different rock types with the exception
of the sandstone which has the lowest conductivity of the rock types considered.
223
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5 Discussion
The expected performance of the alternative hydraulic cage designs is considerably poorer
than the original design. This reflects the difficulty in developing highly conductive fracture
networks in situ and the optimum conditions that can be engineered in an underground
facility. Nevertheless, the results indicate that the surface based methods could divert a
significant portion of the groundwater flow around an area and contribute to the isolation
capability of a disposal site retarding the movement of contaminants. Therefore, the
hydraulic cage represents an additional engineered barrier concept that should be considered
as part of an underground disposal facility.
Underground disposal facilities could be constructed using old underground mines. The
hydraulic cage could be developed using existing openings that are adjacent to a disposal
room or by developing new tunnels. An alternative would be to construct high conductivity
panels that could be placed inside the waste disposal rooms. The high conductivity panels
would be attached to the walls of the disposal rooms and low conductivity materials, such as
bentonite clays, would be added to separate the panels from the waste. The combination of
low and high conductivity barriers would improve the reliability of the inner clay barrier by
decreasing the gradient inside the storage area and reducing the significance of a breach. A
similar approach could be used for surface disposal facilities (Figure 4).
6 References
Axelsson, C-L. and T. Olsson, 1985. "Modeling of groundwater flow and streamlines through
a WP-Cave." Geosystems AB, Uppsala, Sweden.
Strack, O.D. 1985. "Report on Phases 1 ad 2. WP-Cave ground water model." Itasca
Consulting Group Inc., Minneapolis, MN.
224
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Cover
Hydraulic Cage
Slurry Wall-
HOPE Liner
Clay Liner
Figure 4. Conceptual Design of Surface Waste Disposal
Facility Incorporating Hydraulic Cage Barrier
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Innovative Contracting Strategies for Equipment Procurement
Bofors Nobel Superfund Site
Muskegon, MI
Ted H. Streckfuss and Craig Olson
U.S. Army Corps of Engineers, Omaha District
I. Site History: The Bofors Nobel Superfund Site is located six miles east of downtown
Muskegon, Michigan along Evanston Road in Edelston Township. The site is located in a
chemical manufacturing area and is currently owned and operated by Lomac, Incorporated. The
superfund site has been divided by Region V of the Environmental Protection Agency (EPA) into
two operable units, designated as Lagoon Area Operable Unit (LOU), and the Groundwater/Plant
Area Operable Unit (GOU). The LOU is irregularly shaped and includes ten abandoned sludge
lagoons and associated soils south of the Lomac facility. The POU area consists of the
contaminated groundwater located beneath the entire 85 acre site. The southern boundary of the
site is bordered by Big Black Creek, which has been chosen as the selected point of discharge.
Lakeway Chemicals, Incorporated began producing industrial chemicals in 1960. During
this period, the manufacturing facility produced such chemicals as 3,3-dichlorobenzidine (DCB),
benzidine, and azobenzene for use in alcohol based detergents and as die intermediates. Raw
materials used in the production of these components included fatty alcohols, fatty ether alcohol,
sulfur dioxide, aqua ammonia, muriatic acid, sulfuric acid, nitrobenzene, o-nitrobenzene,
methanol, benzene, sodium chloride and zinc.
During the late 1960's and 1970's, DCB, zinc oxide and other process wastes were
discharged through open trenches to the lagoons located south of the plant area. The lagoons
functioned as either direct discharge basins or overflow settling ponds. The basins do not
226
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themseleves contain a homogeneous waste material. During the 1970's, lagoon berm failures
resulted in the discharge of lagoon sludge into Big Black Creek. The use of lagoons for waste
disposal was discontinued in 1976 when the facility was connected to the Muskegon County
Wastewater Treatment System.
In 1977, Lakeway merged with Bofors Industries, Incorporated and the company name
was changed to Bofors Lakeway, Incorporated. In 1978, the State of Michigan filed a Consent
Judgement against the company. The consent judgement required Bofors Lakeway to remediate
the contamination which had occurred both on and off site. In 1981, a Consent Judgement was
entered into between the State of Michigan and Bofors Lakeway, Inc. calling for full restoration
of the air, land, and waters of the State contaminated through previous operations at the Bofors
site.
In 1981, Bofors Lakeway, Inc. merged with Nobel Industries of Sweden and the company
name was changed to Bofors Nobel, Incorporated. In order to conform with the requirements
stipulated within the consent judgement, Bofors and other investors established the
Environmental Systems Corporation of Michigan (ESCM) to own and operate the PACT™
(Powdered Activated Carbon Treatment) system and a clay lined waste disposal landfill required
by the judgement. The disposal landfill was constructed on site to accept ash from a sludge
pyrolysis process. Before the sludge pyrolysis system was implemented, however, Bofors Nobel
and ESCM filed for bankruptcy.
The Bankruptcy Court granted permission to Bofors Nobel and ESCM to procure a
broker and pursue a potential buyer. Sale of the Bofors assets to Lomac was completed in 1987.
As a part of the sales agreement, an "Agreement and Covenant Not to Sue"* was also entered
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into between the State and Bofors Nobel for the previous contamination of air, ground, and
water caused by facility operators. These agreements and covenants allowed Lomac to operate
the facility independently of previous site activities.
Because of the nature and extent of the contamination on the Bofors Nobel site, the State
of Michigan contacted the U.S. EPA to evaluate the site for possible placement on the National
Priorities List (NPL), pursuant to the Comprehensive Environmental Response, Compensation
and Liability Act (CERCLA) as amended by the Superfund Amendments and Reauthorization
Act (SARA). The EPA conducted their site evaluation, with the results calling for nomination
to the NPL in July of 1988, with listing occurring in March 1989. A Remedial
Investigation/Feasibility Study (RI/FS) was initiated in August 1987 and the Record of Decision
(ROD) for the Bofors Nobel site was signed in September 1990. The ROD addressed
remediation of the lagoons, as well as restoration of the groundwater aquifer.
n. Problem Background: One of the primary concerns associated with the contracting effort
on the Bofors Nobel Superfund Site was the procurement of equipment required to treat the
contaminated groundwater. The previously referenced Feasibility Study and the project ROD
called for Ultraviolet Oxidation (UV Oxidation) as the selected technology for destruction of
organic contaminants contained in the groundwater. The option for effluent discharge spelled
out in the ROD mandated a restrictive discharge requirement which had not been considered in
the Feasibility Study. The Feasibility Study had considered the groundwater treatment system
as necessary only for "pretreatment" prior to discharge to the sanitary sewer. The final ROD,
however, directed final effluent discharge to a cold water trout stream located on site. Rapid
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and complete evaluation of the chosen technology was performed to determine whether the low
discharge levels for the organic contaminants contained within the groundwater could be
achieved. The results of this study indicated that the technology was suitable for application on
a waste of this type.
The relatively recent development of the UV Oxidation technology has limited the
corporate competition within this field. To date, only three vendors have exhibited the
capabilities necessary to effectively treat a groundwater contaminated with both volatile and
semivolatile constituents on a full scale basis. An important factor to consider when reviewing
this treatment technology is the high operational and maintenance costs (O&M) associated with
its use. In the case of the Bofors Nobel groundwater treatment system, the O&M costs for the
UV Oxidation system were projected to comprise the majority of the annual operational expense.
Because of this fact, consideration was given to life cycle cost rather than simply capital cost
during the design and predesign phase of the project. By promoting a predesign effort that
emphasized treatment capability as well as life cycle cost, the most effective system could
ultimately be procured for the contract. Based upon the outcome of the predesign testing, a sole
source justification would be initiated to procure that UV Oxidation system deemed to be most
appropriate for this specific groundwater application. Justification would be contingent upon the
capability of the system to treat the contaminated groundwater to acceptable levels, and life cycle
cost to the end user.
HI. Nature of the Corporate Technologies: At the time contractors were being solicited for
the treatability and predesign work associated with this superfund site, there were essentially
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three vendors who had demonstrated proven technologies at non-related sites. The three
corporations have expended a great deal of energy in the promotion of their specific technology
as the "best" for implementation under conditions similar to those present at the Bofors site.
The traditional method for determining full scale operational parameters for UV
Oxidation has been to provide a specific vendor with samples of the contaminated water. The
vendor is responsible for sampling and testing the water sample for various water quality
parameters, and to then use laboratory scale equipment to determine the optimum operational
parameters for full scale equipment. An alternative that each of the vendors has available is use
of a pilot scale treatment system which is mobilized to an individual site. An on site pilot scale
system yields more accurate results regarding upsizing criteria for full scale implementation than
does bench scale treatability testing.
Following the gathering of this predesign data, the project design is normally developed
in a generic fashion, whereby any one of the three vendors would have an equal opportunity to
bid on a project and potentially be awarded the contract for supply, based upon the lowest bid.
The plans and specifications are normally prepared with a performance requirement, so that the
successful bidder is contractually obligated to perform to predetermined levels. The train of
thought on the Bofors project was to provide an opportunity to all vendors to travel to the site,
treat the contaminated groundwater, and propose a full scale system suitable for the treatment
of the contaminants. Based upon the validated laboratory data and the vendor reports, a decision
regarding the most appropriate vendor would be made, and the project design would proceed
around a specific vendor, rather than around a generic performance requirement. Life cycle cost
would figure highly in the decision making process. It was felt that the costs associated with
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the predesign effort would be more than offset by the savings associated with annual O&M over
the life of the project.
IV. Lessons Learned Guidance: At the same time that the Bofors Nobel project was planning
its predesign requirements, a nearby superfund site was performing treatability testing on a waste
stream of similar quality and clarity. The choice of a UV Oxidation vendor for the other
superfund site's treatability testing was based upon which vendor provided the lowest quote for
performing the work. The results of the bench scale treatability testing by that specific vendor
indicated that the O&M requirements for a UV Oxidation system would exceed the initial capital
cost of a complete system within approximately two years. Because of the excessive cost
associated with the UV Oxidation technology at this site, this treatment alternative was removed
from consideration. Other UV Oxidation vendors claimed they could treat the waste stream at
a significantly lower cost but were not considered because of time constraints.
Based on the results of the bench scale testing at the other superfund site, it was felt that
the alternate contracting techniques previously discussed should be investigated for application
at Bofors Nobel. Because each individual UV Oxidation vendor holds patents on their
equipment and all market their equipment as "significantly different" from the other competitors,
it was determined that the most appropriate course of action would be to compare each of the
three available UV Oxidation vendor's products under identical conditions. This decision led
to a "treat-off between the vendors at the Bofors Nobel site. All vendors were contracted to
be on site during a specific time frame, and all vendors were provided the contaminated
groundwater from a common header. The results of the testing period are discussed in
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subsequent paragraphs.
V. Buy American Act Applicability: One of the proven UV Oxidation companies selected for
the on site treatability testing is wholly owned and manufactured outside the United States. This
was a concern because of potential conflicts with the Buy American Act restrictions contained
within the federal procurement regulations. If the non-American produced equipment was found
to be most competitive, on the basis of treatment capability and cost effectiveness, the ability
and legality of a government contract to purchase the process equipment was questionable. This
issue was quickly resolved upon further investigation within the Corps. Reference to Part 25,
subpart 25.1, section 25.101 of the Federal Acquisition Regulations indicated that "Components,
as used in this subpart, means those articles, materials, and supplies incorporated directly into
the end products." The section continues "End Products, as used in this subpart, means those
articles, materials, and supplies to be acquired for public use under the contract." Further
review of the section indicated that "On acquisitions above $25,000 in value, components of
Canadian origin are treated as domestic." These issues specifically applied to the concern
regarding the use of a Canadian manufactured and supplied UV Oxidation system. With these
passages in mind and according to the FAR, the UV system marketed by the Canadian supplier
would qualify as a Buy American product if procured through a supply contract, or provided as
Government Furnished Equipment.
The equipment could be legally provided under a construction contract, but the approval
process would be lengthy and the product would have to qualify for a waiver under the FAR.
Waiver to the FAR involves one of three potential scenarios:
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a) If the cost of the Canadian product is less than the American product by ten percent
after all tariffs, taxes, and fees, the product would qualify;
b) If the usage of any other product is "impracticable", the foreign product would
qualify; and,
c) If there are no American products which meet the job requirements, the foreign
product would be acceptable.
The DoD further determined that application of the Buy American Act to the end
products of Canada and other specific countries (under subpart 225.103) would be inconsistent
with the public interest.
VI. Presentation of Concept to Applicable Entities: The concept of providing an avenue for
all competent and capable vendors to treat the Bofors groundwater from a common header had
previously not been used within the Omaha District Corps of Engineers. The task remained to
coordinate with the other parties involved in the preparation or approval of the completed set
of plans and specifications. Concurrence from the Contracting Division of the Corps, the state
of Michigan and the U.S. EPA, Region V were all necessary prior to proceeding with the
development of a workplan suitable for the on site treatability testing. By emphasizing the
expected recurrent annual O&M costs associated with a UV Oxidation system, it was shown that
the overall cost associated with the up-front (predesign) testing could be recouped, with both the
state and the government potentially saving a significant amount of money. All appropriate
agencies concurred with the concept of treatability testing with all three vendors brought on site
during the same time period.
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The capital costs associated with the unit process were also a primary consideration, but
overall life cycle costs would be the ultimate vehicle used in the selection of the successful
equipment supplier. The first and foremost criterion within the predesign treatability testing was
the capability of the individual vendor to successfully treat the combined purge well flow to
acceptable discharge levels, as defined by the state of Michigan. Upon successfully meeting this
criterion, the vendor was subsequently reviewed on the basis of expected life cycle cost.
Following completion of the treatability testing and receipt of the individual vendors final
reports, the Corps made the decision as to the most appropriate vendor to be incorporated within
the final design of the groundwater treatment plant.
VII. Performance of On-site Treatability Testing: The UV Oxidation vendors were brought
on site to determine the efficacy of their individual treatment processes. The specific testing
objectives, based upon the workplan prepared by the Corps, were as follows:
a) Evaluate the effectiveness of the individual vendor treatment systems at treating the
combined purge well flow. See Table 1 for the analytical results of the raw groundwater.
b) Determine specific design parameters such as required oxidation time and
pretreatment requirements necessitated by the site specific groundwater.
c) Monitor and define the individual vendor's electrical consumption and chemical usage
(if applicable) during the system optimization and performance periods. This information was
subsequently used to estimate and establish the requirements for the full scale systems.
d) Determine any interferences caused by the native raw water quality, and define any
pretreatment requirements necessary for adequate treatment of the contaminated groundwater in
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the proposed full scale system.
TABLE 1
DETECTED ORGANIC COMPOUNDS - UV OXIDATION PILOT TESTING
COMBINED PURGE WELL MANIFOLD
Bofors Nobel Superfund Site, Muskegon, MI
Concentration: ug/1
Volatile Organic
Compounds
Benzene
Chlorobenzene
1,2- Dichloroethane
trans 1,2-Dichloroethene
Ethylbenzene
Methylene Chloride
Tetrachloroethylene
Toluene
1,1,2- Trichloroethane
Trichloroethylene
Vinyl Chloride
Xylene
..^.i ..." "->;« •• ' ' '
Concentration: ug/1
Semi-Volatile Organic
Compounds
Benzidine
1 , 2-Dichlorobenzene
1 , 4-Dichlorobenzene
DCB
Isophorone
1,2, 4-Trichlorobenzene
2-Chloroaniline
Aniline
Dichlorobenzidine Isomer
Benzidine Isomer
Sampling Date
2/89 -
5/91(A)
ND-1800
ND-120
ND-6
ND-200""
ND-70
ND-90'0
66 - 340
ND-1500
ND-40
ND-50
ND-80
ND-40
14 Aug
1991
1400
140
ND
170m
34
15
320
750
ND
77
120
43
27 Sep
1991
1400
160
ND
170™
51
47
320
1500
ND
91
110
73
1 Oct
1991
1900
220
ND
200""
61
53
470
2000
ND
120
120
88
2 Oct
1991
1700
190
ND
ISO"'
67
200
360
1700
ND
110
150
91
" J, " ' '' , ,"'"' '" " "'''' ",""*_ '<"',' :: ,»*" *'"(' "'; "
Sampling Date
2/89 -
5/91(A)
ND-970
ND-12
ND
ND-210
ND-19
ND
71-1500
83-250
320-680
ND-1300
14 Aug
1991
360
30
ND
120
7
ND
1400'°'
140
NR
NR
27 Sep
1991
930
28
2
180
ND
4
760™
230
NR
NR
1 Oct
1991
390
18
ND
100
ND
ND
1100™
110
NR
NR
2 Oct
1991
590
23
1
110
14
3
740™
160
NR
NR
*** Data from Michigan Department of Natural Resources
<"> Reported as total 1,2-DCE
10 Methylene Chloride data from Groundwater FS (GZA/Donohue, 1989)
-------
semivolatile constituents compare favorably with results from previous sampling activities.
The existing groundwater manifold transporting contaminated groundwater to the Lomac
PACT™ facility was tapped to provide water to the treatment area established for the purpose
of the predesign testing. The four inch manifold line was then split into three feeds to service
each individual vendor's equipment. The data from the 14 August 1991 sampling round was
sent to each of the individual vendors prior to their coming to the Bofors site for equipment
setup purposes. This information allowed the vendors to tentatively establish and initial starting
point, based upon institutional knowledge gained from previous operating experience. Specific
mention was made to the vendors that well cleaning activities in early September had generated
a groundwater that was noticeably colored, and which carried a higher suspended solids
concentration than had previously been experienced. Each vendor was instructed that the
responsibility for any pretreatment activity was strictly their own. Non-potable water for use
in equipment cooling and decontamination was brought to the treatment area through the
construction of a temporary pipeline from an existing well located on site. Each vendor was
supplied electricity for their individual process through the use of a 150 kW portable generator.
The electrical usage was monitored through a microprocessor based meter on each connection.
Each vendor was instructed that the intent of the on site testing, was to treat the
contaminated groundwater to a level suitable for discharge to Big Black Creek. The preliminary
discharge standards were established by the state of Michigan, and are contained in Table 2.
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UV/OXIDATI01
PRELIMI
Bofor
1
Compound
Aniline
Azobenzene
Benzene
Benzidine
3,3' -Dichlorobenzidine
Methylene Chloride
Acetone
Butyl Benzyl Phthalate
Chlorobenzene
Dichloroazobenzene
3, 3-Dichlorobenzidine Isomer
Dichlorobiphenyl
TBD = To Be Determined
TAB]
V ON SITE
NARY DIS(
B Nobel .
luskegon,
Cone.
(ug/1)
4.0
TBD
5.0
0.04
0.06
5.0
500.0
5.0
5.0
5.0
0.06
5.0
LE 2
PILOT SCALE TESTING
2HARGE STANDARDS
Superfund Site
Michigan
Compound
1 , 2-Dichloroethane
1 , 2-Dichloroethylene
Trans-1 , 2-Dichloroethylene
Ethylbenzene
Isophorone
Phenols
Tetrachloroethylene
Toluene
Trichloroethylene
1,2, 4-Trichlorobenzene
Vinyl Chloride
Xylene
Cone
(ug/i)
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
, 5.0
5.0
5.0
5.0
Each vendor erected their equipment on the 110'x 30' asphalt pad constructed for the
pilot test. A three inch lip was constructed around the periphery of the pad to contain any
potential leakage. Any water captured on the pad was drained to the effluent tank to be
subsequently discharged to the PACT™ treatment system.
The initial three days of the on site treatability testing period were devoted to equipment
unloading and setup. Approximately two days were expended making the necessary plumbing
and electrical connections.
Two separate sampling and analysis activities were performed during the on site
treatability testing. The initial round of samples was taken by the vendors during the system
adjustment period. Each individual vendor was responsible for the sampling, shipping, and
receipt of the sample analysis in the required turnaround time. A one to three day turnaround
time was contracted during the system adjustment period. This was necessary due to the nature
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of the on site testing. This stringent turnaround time was not required for the optimization
monitoring period. The results obtained from the initial system adjustment period were used to
determine the appropriate unit dosages for the optimization period. The specific analytes were
chosen by the vendor based upon the most critical compound which dictated the chemical usage
and flow rates from their equipment.
The second sampling event occurred during the optimization monitoring period. A
specified number of samples were taken by the vendors at common sampling times. The
optimization monitoring period was a two day cycle during which time the vendors operated
their equipment ten to twelve hours a day. Each of the three systems was allowed to equilibrate
prior to being sampled.
VIII. Results and Conclusions:
A. Metals and Water Quality Data: Tables 3, 4, and 5 show the results for specific
metals and water quality parameters which were monitored during the performance period. The
data were taken to verify raw water quality and to monitor the pretreatment of the individual
vendors. All three vendors utilized a pretreatment filter on the influent line supplying the
process equipment, although the filters were of different mesh sizes. Vendor #1 utilized a
pretreatment tank prior to the pressure filters to remove iron and manganese in the raw water.
Sodium hydroxide and hydrogen peroxide were added to the holding tank to form floe particles
prior to filtration. Vendors #2 and #3 utilized conventional cartridge filters to remove suspended
solids. Table 3 indicates that the measures taken by Vendor #1 were relatively ineffective in
terms of overall removal of the iron and manganese. The pretreatment system used by Vendors
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#2 and #3 had no appreciable affect on the water quality parameters. Acid addition to improve
the performance of their individual processes was performed by both Vendors #1 and #2. The
use of acid in the process train significantly lowered the alkalinity of the groundwater, and
elevated the Total Dissolved Solids of the flow. Other water quality changes worthy of mention
include the oxidation of nitrite to nitrate and the reduction of the total COD by Vendors #2 and
#3. Vendor #1 did not experience either of these changes. The inability of Vendor #1 to affect
these changes may be attributed to a non-optimized system. All vendors experienced only a
slight reduction in the Total Organic Carbon (TOC) as the groundwater was treated. This may
be attributed to the formation of daughter products during the oxidation process.
B. Volatile Organic Compound Analysis: Tables 6, 7, and 8 provide information
relating to the performance of the vendor equipment on treating volatile organics (VOCs)
contained within the contaminated groundwater. Based upon the final reports submitted by the
vendors, tetrachloroethylene (PCE) was indicated as the most recalcitrant of the VOCs in this
water matrix. The influent concentrations of toluene and benzene are typically more than four
times higher than the PCE concentration, however, these compounds are rapidly reduced in all
of the vendor's systems. In general, the chlorinated compounds such as 1,2-Dichloroethane
(1,2-DCA), PCE and Trichloroethylene (TCE) are the most difficult to degrade due to the higher
energy associated with the molecular bonds in these saturated organic compounds. Other
compounds such as acetone and methylene chloride were present in the effluent, but these VOCs
are common laboratory contaminants, and the results may not be reflective of actual conditions.
*
In general, vendor's #2 and #3 were able to effectively treat the contaminated groundwater to
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the required discharge levels. The removal of PCE was typically down to the discharge limit
of 5 ppb. The final effluent for Vendor #3 did contain PCE and benzene above the discharge
standards during one sampling event. The reason for exceeding the discharge level is uncertain,
since the system was capable of meeting the discharge levels during the other sampling events.
Both vendors #2 and #3 had occasional hits on methylene chloride, 1,2-DCA, and TCE, but
these values were near detection limits and are within the bounds of the analytical accuracy.
Vendor #1 experienced difficulty in meeting the discharge limits for several VOCs, indicating
that their system may not have been optimized because the vendor #1 system had sampled and
met the discharge criteria during the system adjustment period.
C. Semivolatile Organic Chemical Analysis: The sample results for the semivolatiles
(SVOCs) contained within the process flow are shown in Tables 9, 10, and 11. These data
indicate that the pretreatment filters used by the vendors appeared to remove small amounts of
aniline, while other SVOC concentrations did not appear to be affected. Vendors #2 and #3
were able to reduce the levels of the SVOCs to the required levels, while Vendor #1 experienced
difficulties in the removal of several SVOCs. The Vendor #3 system did experience hits on
benzidine and isophorone for a portion of the pilot testing. Vendor #3 indicated that the timing
of those infractions was at the same time the systems hydrogen peroxide feed was experiencing
mechanical problems. Both vendors #2 and #3 were effective in reducing the concentrations of
tentatively identified compounds (TICs), while vendor #1 experienced limited success.
IX. Sole Source Procurement Strategy and Design Preparation: Based upon the data and the
reports provided b,y the vendors, the Corps of Engineers selected a vendor around which the
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design package would be prepared. Selection of a vendor was based upon a two phase screening
process. The screening process relied upon two criterion to define the most appropriate vendor
for the full scale system. The first criterion was defined as the ability of the vendors to
effectively treat the waste constituents. Following this primary screening process, the second
screening criterion was used to select the vendor to be used in the project design. The second
criterion was cost related. The vendor which indicated the lowest life cycle cost was selected
over the other vendors which met the first criteria. See Table 2A for data regarding cost data
generated by the vendors during the testing period.
Following the report review, the vendors were contacted regarding the selection results.
The groundwater treatment facility footprint was defined based upon dimensions provided by the
UV Oxidation vendor. The selected vendor was also contacted periodically during the design
phase to coordinate mechanical, electrical, and structural requirements.
A number of benefits associated with this contracting methodology became apparent as
the process design continued. Specifically, the following items were streamlined or clarified as
a result of this innovative contracting attempt:
a) The building footprint becomes easier to develop when the exact dimensions of the
required equipment are obtained from the vendor.
b) The electrical loads, known to vary considerably depending upon the selected vendor,
may be obtained early in the design. This facilitates the entire design and control sequence.
c) The process piping may be clearly defined and shown. Specific elevations may be
coordinated with the vendor to insure compatibility with the remainder of the process train.
d) Pretreatment requirements, which may vary depending upon the vendor, can be
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defined and incorporated into the process design.
e) The contract specifications are stream-lined when a specific vendor has been selected.
This allows the designer to call for specific pieces of process equipment, provided that the
appropriate approvals have been obtained prior to contract advertisement.
TABLE 2A: VENDOR PROJECTED COST DATA
Annual Cost:
Category
$/year
UV Energy1
Replace Lamps
Peroxide Use2
Acid
Base
Catalyst3
Ozone Elec.
Liquid Oxygen
Total Annual
Total Capital
Life Cycle"
Vendor #1
772,660
90,000
192,300
17,000
74,000
Not Used
Not Used
Not Used
1,145,000
1,325,000
14.22 M
Vendor #2
Alt. #1 Alt. #2
with
catalyst
735,000
189,000
448,000
33,000
147,000
19,000
Not Used
Not Used
1,571,000
1,575,000
19.27 M
without
catalyst
572,000
147,000
1,120,000
17,000
74,000
Not Used
Not Used
Not Used
1,930,000
1,575,000
23.30 M
Vendor #3
Alt. #1 Alt. #2
with O2
feed
44,300
22,600
65,700
Not Used
Not Used
2,000
113,900
441,700
690,200
1,510,000
9.28 M
with air
feed
44,300
22,600
65,700
Not Used
Not Used
2,000
219,000
Not Used
353,600
1,695,000
5.68 M
' Power costs based upon $0.06/kWh
2 Hydrogen Peroxide costs ($/gal) vary with usage rate
3 Catalyst costs represent proprietary additives or vapor phase treatment
units.
4 Life Cycle costs assume 30 year operating period at 8 percent interest.
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Within the Army Corps of Engineers, special contracting efforts were required to insure
that all appropriate FARs were complied with. The sole source justification to procure the
selected vendor began shortly after receipt of the final vendor reports. A justification and
approval (J&A) action was necessary to insure that the government was obtaining a system
capable of meeting all necessary requirements. After approval is granted for sole source
procurement, the contract documents are simplified by calling for a specific manufacturer. To
insure that there were no other vendors capable of providing suitable equipment for this
installation, a "Sources Sought" effort was initiated. The results of this request conclusively
indicated that the three vendors targeted for the "treat-off were the only vendors suitable for
this application.
X. Conclusions: The predesign, design and contracting efforts performed for the procurement
of the UV Oxidation equipment in the Bofors Nobel Groundwater Treatment Facility were
shown to be extremely effective. This contracting technique allowed the government to attempt
to procure proven process equipment, capable of meeting stringent discharge standards, and still
provide a cost effective treatment system. The ability to allow all available vendors an
opportunity to test their equipment concurrently has been shown to be an effective tool which
facilitates the procurement of high cost equipment items. Although perhaps not suitable for all
superfund sites because of project specific constraints, the "treat-off technique proved to be
very worthy of the high expectations originally targeted. In this specific instance, it is estimated
that the use of the "treat-off technique will save the government in excess of five million dollars
during an estimated thirty year operating cycle, with the cost of the predesign treatability testing
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recouped within six months. If traditional contacting techniques had been used in the
procurement of a UV Oxidation vendor, the selected vendor would not have been awarded the
contract because of higher initial capital cost. Although the selected vendor's equipment carries
a slightly higher capital expense, the life cycle cost of the process has been shown to make this
innovative contacting mechanism eminently suitable for the Bofors Nobel Superfund site.
244
-------
TABLE 3
UV OXIDATION TESTING: METALS AND UATER QUALITY
VENDOR f 1
Bofors Nobel Superfund Site, Muskegon, Michigan
Predesign Testing
ANALYTE CONC.
(ug/l)
Arsenic
Calcium
Iron
Manganese
Magnesium
Zinc
Combined Purge Well Manifold
9/27
1991
4.6
.
1530
405
.
38
ANALYTE
Concentration (mg/l)
COO (Total)
Alkalinity
Chloride
Sulfate
Ammonia Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Total Kjeldahl
Nitrogen
Phosphorus
IDS
TSS
TOC I
TOG II (Dup)
pH, Laboratory
52
248
97.5
283
9.35
0.24
0.091
11.8
0.16
743
3
14.2
15.0
7.34
10/1
1991
3.9
-
1440
408
.
44
10/2
1991
4.3
108,000
1380
401
19,300
38
52
236
92.8
210
7.26
0.17
0.077
11.6
0.16
717
<2
12.6
12.8
7.17
50
230
94.8
230
7.79
0.18
0.058
12.6
0.18
740
<2
14.0
14.0
7.20
After Pretreatment
UV Oxidation Influent
9/27
1991
4.7
-
1070
288
-
<15
55
11.8
99.5
429
10.9
0.22
0.079
12.3
0.14
1130
1
14.8
14.0
5.01
10/1
1991
4.5
-
1120
293
-
85
10/2
1991
3.9
86,600
1220
279
18,700
279
52
68.2
95.6
277
10.5
0.20
0.051
10.5
0.14
897
<1
12.5
12.4
5.85
52
74.9
97.4
334
7.89
0.18
0.064
12.0
0.15
917
<2
12.2
12.2
5.94
Intermediate
9/27
1991'"
4.5
-
1110
288
-
305
10/2
1991181
4.3
-
1050
269
-
54
UV Oxidation System
Effluent
9/27
1991ICI
5.1
-
1050
303
-
<15
76
58.3
96.9
376
9.50
0.14
0.094
11.3
0.17
910
<2
12.4
12.6
5.93
67
63.3
99.0
353
7.78
0.14
0.096
11.9
0.14
890
<2
11.9
11.9
5.92
58
9.06
99.4
396
10.9
0.17
0.097
12.4
0.15
960
0
13.2
13.1
4.95
10/1
1991
4.8
-
1180
291
-
517
71
51.0
97.3
457
6.93
0.17
0.066
11.3
0.14
930
<2
12.0
12.0
5.82
10/1
1991
4.5
-
1330
320
-
37
77
87.5
97.7
392
8.15
0.15
0.088
11.3
0.16
820
<2
12.0
12.1
6.09
10/2
1991
4.5
87,000
992
268
19,400
54
67
63.4
98.8
332
8.63
0.13
0.082
13.3
0.14
912
<2
11.9
11.8
5.85
10/2
1991
4.4
-
1420
317
-
26
70
71.7
97.6
461
7.60
0.16
0.089
11.9
0.15
983
<2
12.7
13.0
5.96
'" Intermediate Sampling Point after Lamp #3 (50% Retention Time)
"" Intermediate Sampling Point after Lamp #4 (67% Retention Time)
'C1 Effluent Sample taken on 27 September 1991 during equipment adjustment period.
- Not Analyzed For
-------
NJ
-fc.
ON
ANALYTE COMC.
(ug/l)
Arsenic
Calcium
Iron
Manganese
Magnesium
Zinc
-,
TABLE 4
UV OXIDATION TESTING: HETALS AND UHTER QUALITY
VENDOR *2
Bofors Kobel Superfund Site, Huskegon, Hichigan
Predesign Testing
Combined
9/27
1991
4.6
-
1530
405
-
38
Purge Well Manifold
10/1
1991
3.9
-
1440
408
-
44
10/2
1991
4.3
108,000
1380
401
19,300
38
After Pretreatment
UV Oxidation Influent
9/27
1991
4.5
-
1780
404
-
17
10/1
1991
4.2
-
1320
413
-
78
10/2
1991
4.3
113,000
1320
410
18,400
26
Intermediate
9/27
1991'"
5.0
.
13,700
487
.
<15
10/2
1991'"
4.5
.
13,600
500
_
41
UV Oxidation System
Effluent
9/27
1991KI
5.0
_
1590
386
_
58
10/1
1991
4.9
13,300
491
45
10/1
1991
5.1
18,800
523
78
ANALYTE
Concentration (mg/l)
1 COD (Total)
Alkalinity
Chloride
Sulfate
Ammonia Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Total Kjeldahl
Nitrogen
Phosphorus
TDS
TSS
TOC I
TOC II (Oup)
pH, Laboratory
52
248
97.5
283
9.35
0.24
0.091
11.8
0.16
743
3
14.2
15.0
7.34
52
236
92.8
210
7.26
0.17
0.077
11.6
0.16
717
<2
12.6
12.8
7.17
50
230
94.8
230
7.79
0.18
0.058
12.6
0.18
740
<2
14.0
14.0
7.20
49
248
98.0
123
7.60
0.20
0.072
12.3
0.19
750
<4
13.0
13.3
7.37
46
236
93.4
167
7.58
0.18
0.069
11.7
0.17
714
<2
13.0
13.2
7.24
49
237
94.7
238
8.64
0.19
0.051
12.2
0.15
723
<2
13.4
13.6
7.26
28
<5
95.3
658
8.80
0.27
<0.050
11.1
0.59
977
<2
9.6
9.5
2.55
39
<5
98.2
492
8.98
0.27
<0.050
11.3
0.66
967
1
10.5
10.4
2.41
67
229
97.7
267
9.72
0.27
0.096
12.2
0.85
813
1
10.7
10.8
7.00
'" Intermediate Sampling Point after Lamp #2 (67% Retention Time)
" Intermediate Sampling Point after Lamp #1 (33% Retention Time)
IC' Effluent Sample taken on 27 September 1991 during equipment adjustment period.
- Not Analyzed For
18
<5
94.8
568
7.97
0.26
<0.050
11.5
0.59
937
3
8.5
8.7
2.53
27
<5
96.9
623
8.08
0.27
<0.050
11.6
0.66
1040
3
8.4
8.1
2.57
10/2
1991
4.1
112,000
13,300
492
18,300
140
22
<5
97.8
518
9.00
0.29
<0.050
11.1
0.67
965
6
8.2
8.6
2.42
10/2
1991
4.8
16,000
509
35
39
<5
97.1
192
8.66
0.31
<0.050
13.5
0.80
1010
4
8.4
8.5
2 47
-------
TABLE 5
UV OXIDATION TESTING: METALS AND WATER QUALITY
VENDOR *3
Bofors Nobel Superfund Site. Huskegon, Michigan
Predesign Testing
ANALYTE COHC.
(ug/l)
Arsenic
Calcium
Iron
Manganese
Magnesium
Zinc
Combined Purge Well
Manifold
9/27
1991
4.6
-
1530
405
-
38
10/1
1991
3.9
-
1440
408
-
44
10/2
1991
4.3
108,000
1380
401
19,300
38
After Pretreatment
UV Oxidation Influent
9/27
1991
4.6
-
1600
400
-
51
10/1
1991
4.2
-
1290
405
-
32
10/2
1991
3.94.3
113,000
1520
410
18,400
88
Intermediate
9/27
1991'"
4.8
-
1250
408
-
<15
10/2
1991""
4.0
.
1240
406
-
49
UV Oxidation System
Effluent
9/27
1991"'
5.5
.
1470
391
-
29
10/1
1991
4.6
.
1190
394
-
243
10/1
1991
5.0
.
1260
399
-
649
10/2
1991
4.3
117,000
1350
417
19,200
93
10/2
1991
4.4
_
1200
416
_
61
ANALYTE
Concentration (mg/l)
COD (Total)
Alkalinity
Chloride
Sulfate
Ammonia Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Total Kjeldahl
Nitrogen
Phosphorus
TOS
TSS
TOC I
TOC 11 (Oup)
pH, Laboratory
52
248
97.5
283
9.35
0.24
0.091
11.8
0.16
743
3
14.2
15.0
7.34
52
236
92.8
210
7.26
0:17
0.077
11.6
0.16
717
<2
12.6
12.8
7.17
50
230
94.8
230
7.79
0.18
0.058
12.6
0.18
740
<2
14.0
14.0
7.20
47
246
97.5
239
11.20
0.21
0.075
12.2
0.18
796
<4
13.5
13.3
7.30
50
240
96.3
200
8.65
0.19
0.053
11.2
0.17
740
<2
13.0
12.7
7.18
52
233
94.8
207
7.73
0.18
0.065
11.3
0.18
738
<2
13.4
13.0
7.19
33
225
93.4
259
8.52
0.31
<0.050
11.3
0.18
738
<2
13.6
13.6
7.07
18
206
95.7
265
9.08
0.39
<0.050
11.5
0.18
724
11
10.7
11.0
7.30
<8
212
97.1
280
9.84
0.67
<0.050
11.9
0.20
770
14
7.6
7.7
7.55
16
208
91.8
252
9.50
0.37
<0.050
11.1
0.19
764
7
11.0
10.9
7.09
21
214
94.0
135
7.51
0.34
<0.050
11.6
0.18
767
7
11.2
11.2
7.16
15
207
95.3
279
8.30
0.40
<0.050
11.3
0.15
732
10
10.6
10.4
7.23
32
219
94.3
124
8.45
0.31
<0.050
10.6
0.17
748
<2
13.1
13.1
7.41
'*' Intermediate Sampling Point after Lamp #3 (50% Retention Time)
'• Intermediate Sampling Point after Lamp #5 (83% Retention Time)
10 Effluent Sample taken on 27 September 1991 during equipment adjustment period.
- Not Analyzed For
-------
00
TABLE 6
UV OXIDATION TESTING: VOLATILE ORGANIC COMPOUNDS
VENDOR *1
Bofors Kobe I Superfund Site, Huskegon, Michigan
Predesign Testing
AHALYTE COHC.
(ug/l)
Vinyl Chloride
Methylene Chloride
Acetone
1,2-Dichloroethene (total)
1,2-Dichloroethane
Trichloroethene
Benzene
Tetrachloroethene
Toluene
Chlorobenzene
Ethyl benzene
Xylene (total)
Corrfoined Purge Well
Manifold
9/27
1991
110
47
30
170
<50
91
1400
320
1500
160
51
73
10/1
1991
120
53
<140
200
<68
120
1900
470
2000
220
61
88
10/2
1991
150
200
<140
180
<72
110
1700
360
1700
190
67
91
After Pretreatment
UV Oxidation Influent
9/27
1991
77
24
150
140
<31
81
1100
290
910
120
31
33
10/1
1991
60
16
22
120
<38
77
1200
340
920
120
26
32
10/2
1991
34
73
69
91
<33
58
870
190
660
100
<33
28
Intermediate
9/27
19911*1
20
10
19
47
<10
30
310
140
200
35
6
6
10/2
1991'"
18
8
36
45
<5
27
220
110
110
26
4
4
UV Oxidation System
Effluent
9/27
1991*'
10
17
63
23
<5
16
120
71
57
14
2
<5
10/1
1991
<10
3
31
13
8
9
60
50
21
7
<5
<5
10/1
1991
8
4
25
19
8
13
87
68
34
10
1
<5
10/2
1991
4
4
25
21
10
12
83
65
31
10
1
<5
10/2
1991
13
5
24
30
10
18
120
96
47
15
2
<5
'" Intermediate Sampling Point after Lamp #3 (50% Retention Time)
'" Intermediate Sampling Point after Lamp #4 (67% Retention Time)
IC1 Effluent Sample taken on 27 September 1991 during equipment adjustment period.
-------
VO
TABLE 7
UV OXIDATION TESTING: VOLATILE ORGANIC COMPOUNDS
VENDOR *2
Bofors Nobel Superfund Site, Nuskegon, Michigan
Predesign Testing
ANALYTE CONC.
(ug/t)
Vinyl Chloride
Methylene Chloride
Acetone
1,2-Dichloroethene (total)
1,2-Dichloroethane
Trichloroethene
Benzene
Tetrachloroethene
Toluene
Chlorobenzene
Ethyl benzene
Xylene (total)
Combined Purge Well
Manifold
9/27
1991
110
47
30
170
<50
91
1400
320
1500
160
51
73
10/1
1991
120
53
<140
200
<68
120
1900
470
2000
220
61
88
10/2
1991
150
200
<140
180
<72
110
1700
360
1700
190
67
91
After Pretreatment
UV Oxidation Influent
9/27
1991
97
65
260
150
<50
92
1400
320
1500
160
50
70
10/1
1991
11
8
16
18
<5
10
170
40
170
19
5
8
10/2
1991
110
38
<37
150
<18
88
1400
320
1500
170
51
81
Intermediate
9/27
1991 '*'
<10
3
35
<5
5
<5
<5
10
<5
<5
<5
<5
10/2
1991™
<10
6
26
4
7
8
9
58
<5
<5
2
<5
UV Oxidation System
Effluent
9/27
19911C1
<10
7
73
<5
4
<5
<5
4
<5
<5
<5
<5
10/1
1991
<10
2
46
<5
4
<5
<5
2
<5
<5
<5
<5
10/1
1991
<10
4
31
<5
4
<5
<5
2
<5
<5
<5
<5
10/2
1991
<10
10
35
<5
4
4
<5
4
<5
<5
<5
<5
10/2
1991
<10
6
38
<5
3
<5
<5
<5
<5
<5
<5
<5
"' Intermediate Sampling Point after Lamp #2 (67% Retention Time)
'" Intermediate Sampling Point after Lamp #1 (33% Retention Time)
ICI Effluent Sample taken on 27 September 1991 during equipment adjustment period.
-------
to
TABLES
UV OXIDATION TESTING: VOLATILE ORGANIC COMPOUNDS
VENDOR *3
Bofors Nobel Superfund Site, Huskegon, Michigan
Predesign Testing
AHALYTE COHC.
(ug/l)
Vinyl Chloride
Hethylene Chloride
Acetone
1,2-Dichloroethene (total)
1,2-Dichloroethane
Trichloroethene
Benzene
Tetrach loroethene
Toluene
Chlorobenzene
Ethylbenzene
Xylene (total)
Combined Purge Well
Manifold
x/27
1991
110
47
30
170
<50
91
1400
320
1500
160
51
73
10/1
1991
120
53
<140
200
<68
120
1900
470
2000
220
61
88
10/2
1991
150
200
<140
180
<72
110
1700
360
1700
190
67
91
After Pretreatment
UV Oxidation Influent
9/27
1991
<100
47
180
180
<50
97
1500
350
1700
170
55
79
10/1
1991
120
23
130
200
<50
110
1800
440
1800
220
56
84
10/2
1991
97
18
<25
140
<12
86
1200
320
1500
170
48
71
Intermediate
9/27
1991'"
<10
3
41
9
8
7
35
63
3
5
<5
<5
10/2
1991"
<10
18
44
<5
3
<5
1
3
<5
<5
<5
<5
UV Oxidation System
Effluent
9/27
1991*'
<10
2
48
<5
<5
<5
<5
<5
<5
<5
<5
<5
10/1
1991
<10
6
63
<5
5
<5
1
6
1
<5
<5
<5
10/1
1991
<10
3
45
<5
4
<5
1
7
<5
<5
<5
<5
10/2
1991
<10
15
44
<5
3
<5
1
2
<5
<5
<5
<5
10/2
1991
<10
2
13
4
4
4
18
32
2
2
<5
<5
'*' Intermediate Sampling Point after Lamp #3 (50% Retention Time)
'" Intermediate Sampling Point after Lamp #5 (83% Retention Time)
ICI Effluent Sample taken on 27 September 1991 during equipment adjustment period.
-------
TABLE 9
UV OXIDATION TESTING: SEN I VOLATILE ORGANIC COMPOUNDS
VENDOR *1
Bofors Nobel Stperfund Site, Kuskegon, Michigan
Predesign Testing
ANALYTE CONC.
(ug/l)
Phenol
Aniline
2-Chlorophenol
Benzyl Alcohol
1,2-Dichlorobenzene
2-Hethylphenol
4-Methylphenol
N-Nitroso-Di-n-Propytamine
Isophorone
1,2,4-Trichlorobenzene
4-Chloroaniline
Benzidine
3,3'-Dichlorobenzidine
Combined Purge Well
Manifold
9/27
1991
8
230
3
<10
28
14
6
2
<10
4
10
930
180
10/1
1991
<100
110
<100
<100
18
<100
<100
<10
<100
<100
<100
390
100
10/2
1991
10
160
3
<10
23
12
5
1
14
3
7
590
110
After Pretreatment
UV Oxidation Influent
9/27
1991
130
64
19
6
18
48
83
<10
14
3
3
7
61
10/1
1991
51
85
7
1
24
23
30
1
14
3
7
140
130
10/2
1991
<10
<10
<10
3
28
19
23
<10
13
4
9
<50
130
Intermediate
9/27
1991'*'
100
17
20
5
9
89
77
<10
22
1
<10
<50
<20
10/2
1991""
<10
<10
<10
5
8
67
58
<10
23
1
<10
<50
<20
UV Oxidation System
Effluent
9/27
1991'°'
<10
<10
<10
<10
<10
<10
<10
<10
5
<10
<10
<52
<21
10/1
1991
32
2
8
2
1
16
16
<10
14
<10
<10
<50
<20
10/1
1991
39
5
10
3
3
25
26
<10
15
<10
<10
<50
<20
10/2
1991
35
4
10
3
3
33
29
<10
17
<10
<10
<50
<20
10/2
1991
<10
<10
14
4
5
52
43
<10
17
<10
<10
<50
<20
'" Intermediate Sampling Point after Lamp #3 (SOX Retention Time)
'" Intermediate Sampling Point after Lamp )W (67% Retention Time)
Kl Effluent Sample taken on 27 September 1991 during equipment adjustment period.
to
-------
TABLE 10
UV OXIDATION TESTING: SEMI VOLATILE ORGANIC COMPOUNDS
VEHDOR K
Bofors Hobel Superfund Site, Muskcgon, Michigan
Predesign Testing
ANALYTE COHC.
(ug/l)
Phenol
Aniline
2-Chlorophenol
Benzyl Alcohol
1 , 2-0 ich lorobenzene
2-Hethy I phenol
4-Methylphenol
N-Mitroso-Di-n-Propylamine
Isophorone
1,2,4-Trichlorobenzene
4-Chloroaniline
Benzidine
3,3'-Dichlorobenzidine
Combined Purge Well
Hani fold
9/27
1991
8
230
3
<10
28
14
5
2
<10
4
10
930
180
10/1
1991
<100
110
<100
<100
18
<100
<100
<100
<100
<100
<100
390
100
10/2
1991
10
160
3
<10
23
12
5
1
14
3
7
590
110
After Pretreatment
UV Oxidation Influent
9/27
1991
9
180
3
1
20
15
6
1
9
3
8
630
130
10/1
1991
8
170
2
<10
22
11
5
<10
<10
"3
7
540
130
10/2
1991
9
150
2
<10
22
11
6
1
<10
3
7
600
120
Intermediate
9/27
1991"'
<10
<10
<10
2
<10
<10
<10
<10
2
<10
<10
<50
<20
10/2
1991""
<10
<10
<10
2
<10
<10
<10
<10
<10
<10
<10
<50
<20
UV Oxidation System
Effluent
9/27
1991ICI
<11
<11
<11
<11
<11
<11
<11
<11
2
<11
<11
<50
<22
10/1
1991
<10
<10
<10
1
<10
<10
<10
<10
1
<10
<10
<50
<20
10/1
1991
<10
<10
<10
1
<10
<10
<10
<10
1
<10
<10
<50
<20
10/2
1991
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<50
<20
10/2
1991
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<50
<20
IAI Intermediate Sampling Point after Lamp #2 (67% Retention Time)
'" Intermediate Sampling Point after Lamp #1 (33% Retention Time)
IC' Effluent Sample taken on 27 September 1991 during equipment adjustment period.
K
-------
TABLE 11
UV OXIDATION TESTING: SEHIVOLATILE ORGANIC COMPOUNDS
VENDOR «
Bofors Nobel Superfund Site. Huskegon. Michigan
Predesign Testing
ANALYTE CONC.
(ug/l)
Phenol
Aniline
2-Chlorophenol
Benzyl Alcohol
1 , 2-D i ch I orobenzene
2-Hethylphenol
4-Methylphenol
N-Nitroso-Di-n-Propylamine
Isophorone
1 ,2,4-Trichlorobenzene
4-Chloroaniline
Benzidine
3,3'-Dichlorobenzidine
Combined Purge Well
Hani fold
9/27
1991
8
230
3
<10
28
14
6
2
<10
4
10
930
180
10/1
1991
<100
110
<100
<100
18
<100
<100
<100
<100
<100
<100
390
100
10/2
1991
10
160
3
<10
23
12
5
1
14
3
7
590
110
After Pretreatment
UV Oxidation Influent
9/27
1991
16
190
4
5
25
24
6
<10
<10
3
9
790
160
10/1
1991
<10
91
3
<10
22
12
7
3
12
3
7
620
150
10/2
1991
9
150
2
<10
21
11
5
1
<10
3
7
580
110
Intermediate
9/27
1991'"
6
<10
<10
1
2
2
4
<10
10
<10
<10
<50
<20
10/2
1991"
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<50
<20
UV Oxidation System
Effluent
9/27
19911CI
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<50
<20
10/1
1991
<10
<10
<10
<10
<10
<10
<10
<10
1
<10
<10
<50
<20
10/1
1991
<10
<10
<10
<10
<10
<10
<10
<10
2
<10
<10
<50
<20
10/2
1991
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
<10
63
<20
10/2
1991
2
<10
<10
<10
<10
<10
<10
<10
8
<10
<10
<50
<20
'" Intermediate Sampling Point after Lamp #3 (SOX Retention Time)
"" Intermediate Sampling Point after Lamp #5 (83% Retention Time)
ICI Effluent Sample taken on 27 September 1991 during equipment adjustment period.
to
(Jl
-------
Remediation of Groundwater Contaminated with Volatile Organic
Compounds in the Saturated Zone at a California Superfund Site in
Mountain View, California
R F Battey, D A Burbank, M M Milani, A N Stessman
The Earth Technology Corporation
(formerly Aqua Resources Inc.)
2030 Addison Street, Suite 500
Berkeley, California 94704
254
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Remediation of Groundwater Contaminated with Volatile Organic Compounds
in the Saturated Zone at a California Superfund Site
in Mountain View, California
Historical Site Summary
This site, located in California's "Silicon Valley", was used for the manufacture of printed
circuit boards from the mid-1960s to 1981. Various rinse waters were collected in five
underground storage tanks along one side of a row of buildings. These washing and rinsing
operations reportedly used chlorinated and other solvents. These concrete tanks have been
recently removed and replaced with engineered fill. The buildings on the site are now
occupied by a variety of small industries and service establishments.
The site is a California State Superfund Site. Investigations completed to date include a
Remedial Investigation and a Feasibility Study. A Remedial Action Plan has been devel-
oped and approved by the California Environmental Protection Agency, Department of
Toxic Substances Control. Regulatory oversight during the previous investigations and the
implementation of the Remedial Action Plan has been provided by Department of Toxic
Substances Control.
This paper will cover the remedial investigation, feasibility study, and engineering design of
remediation facilities for the contaminated groundwater using a relatively new treatment
method, which results in the destruction of contaminants, rather than their transfer to
another medium.
Site Characterization
During the remedial investigation, approximately 30 monitoring wells and 25 soil borings
have been completed at the site to characterize the extent of contamination. Figure 1
shows the site layout and locations of monitoring wells. Contamination extends through the
vadose zone into two distinct aquifers, which are separated by an clay layer aquitard. There
are two separate plumes; this discussion will cover only the eastern plume. Two extraction
wells have been installed and used to field test an ultraviolet light hydrogen peroxide
groundwater treatment process. Wells have been monitored for more than two years. The
principal contaminants in the groundwater are shown in Table 1.
Setting
Mountain View is located about 40 miles southeast of San Francisco. The temperate
climate is typical of California coastal areas, with an annual precipitation of 15 to 20 inches,
predominantly in the period from November to March. Summer daytime temperatures are
in the 70s to 80s, with nighttime temperatures in the 60s. Winter temperatures rarely drop
below freezing.
255
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The ground surface at the site is covered by buildings, pavement, and small landscape
improvement areas. Surface topography is relatively flat, and has been locally modified by
grading and other site improvements. The site is located geologically at the base of an
alluvial fan, with the regional ground surface sloping gently to the north toward San Fran-
cisco Bay.
The site geology is characteristic of an alluvial environment which was periodically inun-
dated by bay waters during interglacial periods. The lithology is characterized by inter-
bedded unconsolidated sands, silts, and clays. Three aquifers have been identified and are
referred to as Zones A, B, and C in order of increasing depth. Zone A is a shallow water
table aquifer with a low hydraulic conductivity typical of silty sands. The present saturated
thickness of this zone is only 3.0 ft, down from 6.5 ft in 1987, due to several years of
drought.
Zone B is separated from Zone A by a clay unit 5 to 15 ft in thickness first appearing at a
depth of about 25 ft. The conductive interval of Zone B is characterized by 10 to 15 ft of
sand with varying amounts of clay and gravel, which is locally interbedded with sandy clay.
The hydraulic conductivity of this zone is roughly 5 times that of Zone A. Pump tests
characterize this aquifer as leaky with a hydraulic connection to Zone A. The piezometric
surface of Zone B is approximately the same as the free groundwater surface of Zone A.
Zone C is separated from Zone B by 10 to 15 ft of clay which forms a hydraulic barrier
between the two aquifers. The piezometric surface of this zone is approximately 1 ft higher
than Zones A and B. Groundwater flow in the upper zones is generally to the north toward
the San Francisco Bay with a gradient between 0.002 and 0.003 ft/ft. Figure 2 is a cross
section showing conceptual lithology of the site.
Feasibility Study
A Feasibility Study considered a number of cleanup scenarios for both soil and groundwa-
ter. Chemical oxidation by means of ultraviolet light and hydrogen peroxide was selected as
the treatment method. Extensive field testing has shown that a Perox-Pure LV-60 ultravio-
let light hydrogen peroxidation (UV/PX) unit, manufactured by Peroxidation Systems Inc.
to be effective in reducing concentrations of VOCs to less than 1 ppb and can meet the dis-
charge limits set by a NPDES permit. The treated water will be discharged to the city
storm sewer which ultimately flows into San Francisco Bay.
The UV/PX unit was tested at flows up to 50 gpm, hydrogen peroxide concentrations in the
feed as high as 300 ppm, and power inputs up to 50 MW. Selected initial conditions will be
50 gpm feed, 200 ppm hydrogen peroxide, and four lamps operating (50 MW power).
Hydrogeologic modeling studies have shown that pumping from the Zone B aquifer at a
sufficient rate will capture the contaminated plume in Zone B and simultaneously dewater
Zone A. A parallel soil vapor extraction operation will be carried out in the vadose zone
and the dewatered Zone A.
256
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Facility Design and Construction
The criteria for design of the groundwater extraction and treatment system included:
• Use of the Perox-Pure UV/PX unit furnished by Peroxidation Systems Inc. which
was used in the full-scale field tests. The reactor vessel has been modified with a
new design to improve water flow patterns and minimize bypassing.
• Discharge limits as set by a NPDES Permit; the discharge is ultimately to San
Francisco Bay. Discharge limits for VOCs are 5.0 ug/L each for 1,2-dichloroethy-
lene, trichloroethylene, tetrachloroethylene, benzene, ethylbenzene, and xylenes, and
0.5 ug/L of toluene.
• Provision for discharge to the city sanitary sewer, ultimately to the Palo Alto Waste
Water Treatment Plant. The Industrial Waste Discharge Permit with the City of
Mountain View permits discharge of 750 ug/L of each VOC with a maximum of
1,000 ug/L total VOCs.
• Secondary containment for tanks or equipment containing Untreated groundwater
and 50% hydrogen peroxide solution, either double-walled piping or a bermed area
• Provision to enable unattended operation so that the facility may be serviced once a
week, after the startup is complete
• Automatic shutdown for high water level in the untreated, groundwater storage tank,
water on the floor of the bermed process area, and misoperation or malfunction of
the Perox-Pure unit. Conditions in the Perox-Pure unit causing a shutdown include
low groundwater feed flow rate, low hydrogen peroxide solution pump discharge
pressure, high temperature in any of several locations in the unit, and moisture in
any of several locations in the unit. • •
A detailed design was prepared for the groundwater extraction and treatment system which
included drawings and specifications. Contract documents were also prepared for a com- '
plete bidding package. Bids were received from several local contractors. Construction of
the facility is essentially complete and the startup phase is beginning.
Estimated Costs
The estimated construction cost is $185,000; this does not include the UV/PX unit (it will
be leased under a service agreement), or any .engineering costs. Estimated operating and
maintenance costs for the first year of operation are shown in Table 2 for the first year of
operation.
257
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Table 1. Principal Contaminants in Groundwater
at the Plessey Site
Contaminant
Typical Concen-
trations
(ug/L)
Ethylbenzene
Perchloroethylene
Trichloroethylene
Xylenes
1,2-Dichloroethylene
300
400
8,000
700
600
Table 2. Estimated O&M Costs at the Plessey Site (1st Year)
$1000/yr S/1000 gal
Startup (1)
Equipment Lease (2)
Utilities:
Electricity
Storm Sewer Fees
Other
Operating and Maintenance (3)
Building Rent
Regulatory Activities
Sampling/ Analysis (4)
Hazardous Waste Fees
Special Reports
Total
20.7
59.4
41.0
10.5
1.0
30.5
13.6
38.1
56.2
25.2
297
0.93
2.66
1.84
0.47
0.04
1.37
0.61
1.71
2.52
1.13
13.3
Notes (1) First year only
(2) For UV/PX unit; includes maintenance of the unit and hydrogen peroxide
supply
(3) Routine checking each week and routine reports
(4) Includes sampling labor and analytical laboratory charges
258
-------
.D7
.06
S94.
IsJ
Ui
VO
,T2
S6.
rD10
D8
D2+X +S3
S8
T3
D9
V—
S18 ,
7 1,
TANK D/
\TANK C
TftNK F/
f" 7
TANK B/
\TANK A
TANK S./
+ T5
-1+.+SI5
—• SI I
,D3
+S,3
D4'
S10
,-H-
D5
PROJECT
TRUE NORTH
NORTH
LEGEND
+ SI... - SHALLOW WELLS (A-ZONE)
+ Dl... - DEEP WELLS IB-ZONE)
x D8, D13... - DEEP WELLS (OZONE)
+ Tl... - TEST WELLS (B-ZONE)
NOTES;
WELLS
S1-S4, Dl. D2
S5-S13. D3-D8. Tl
T2, T3, D9-DII
SI4
T4
T5. D12, SIS
INSTALLED
OCT-NOV 1987
MAR-MAY 1988
NOV-DEC 1988
APR J989
JUN 1989
AUG-SEP 1990
TANK E — REMOVED JUN 1989
TANKS A. B, C. D. F --
REMOVED AUG 1991
APPROX SCALE
100 FT
FIGURE 1. MOUNTAIN VIEW SITE MONITORING WELLS
-------
MONITORING-
PRODUCTION
WELL
GROUND SURFACE
SANDY SILT
SAND LENS
WATER LEVEL
ZONES A & B
CONTAMINANT
PLUME
SANDY SILT
FIGURE 2. MOUNTAIN VIEW SITE CONCEPTUAL LITHOLOGY
-------
SOIL WASHING OF LEAD-CONTAMINATED
SOIL AT A FORMER GUN CLUB SITE
Anthony Saracino, Director of Environmental Services
Wallace - Kuhl & Associates, Inc.
West Sacramento, CA 95691
(916) 372-1434
Christine Parent, Associate Hazardous Materials Specialist
Department of Toxic Substances Control
10151 Croydon Way, Suite 3
Sacramento, CA 95827
(916) 255-3707
Abstract
The subject site operated as a rifle range, a pistol range and a trapshooting area from 1976 to 1985.
As a result of a preliminary site assessment, it was determined that surface soil contamination by
paniculate elemental lead in the form of spent bullets and shot existed in certain areas of the site.
Pilot studies performed on representative soil samples indicate that it would be feasible to separate and
remove the lead shot, slugs and fragments from the stockpiled soil using a modified sand and gravel
plant as the treatment plant. Approximately 15,000 cubic yards of contaminated soil were excavated
from various areas of the site and field screened through a one-inch vibratory screen. The finer-
grained material (approximately 9000 cubic yards) was processed in the treatment plant, which utilized
the difference in specific gravity between the paniculate lead and the soil to physically separate and
remove the lead.
The treatment plant consisted of a hopper feeder above a jigging box used to capture the larger lead
slugs and shot, and two sand screws that fed the contaminated soil onto three stacked screens. The
fine material passing the smallest screen was sent through a three-foot-diameter centrifugal separator.
The plant utilized approximately 300 gallons of water per minute, which was stored in two
recirculation settling ponds. Clarified water from the settling ponds was recirculated as part of the soil
washing and material transport water in the plant. The treated soil flowed along a drag tank and was
discharged to ground (beached).
261
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The goal of the treatment process was to remove the participate elemental lead from the fine-grained
soil so that a total lead concentration of less than 170 mg/kg for a given volume of sample was
achieved. The test results showed a high degree of effectiveness in the removal of the free lead,
although some lead remained bound to the silt, clay and organic fractions of the soil. Elemental lead
particles ranging in size from coarse slugs down to approximately 100 mesh were recovered from the
contaminated soil. The mean lead concentration for the treated soil was 181 mg/kg.
Twenty-one drums (31,970 pounds) of recovered lead were transported to a recycling facility. The
treated soil and the coarse-grained, uncontaminated material from the screening operation were used
as backfill beneath a road being constructed on site. The total cost of the soil washing operation,
including all earthwork operations, was approximately one million dollars. The project team consisted
of two consultants and a contractor who worked in conjunction with each other to oversee the remedial
action, conduct the sampling, and to operate the treatment plant.
Introduction
This paper summarizes the investigation and remediation of lead-contaminated soil at a former gun club
site in Folsom, California. The investigation and remediation were part of a Preliminary
Endangerment Assessment (PEA) performed for the site; the PEA legislation was enacted in 1989,
which allowed the State of California Department of Health Services (currently Cal EPA, Department
of Toxic Substances Control) to oversee PEA projects.
The study site comprised approximately 40 acres in Folsom, Sacramento County, California, and the
overall property is to be developed into a residential subdivision. The site was purchased by the
Orangevale Sportsman Club, Inc. in February, 1976. Three relatively isolated areas of the site were
used by the club for target shooting; the shooting was directed into soil berms designed to trap the
spent bullets. The berms were constructed of on-site materials consisting primarily of sand, gravel
and cobbles. Another portion of the site was used for trapshooting. The trapshooting operations
resulted in particulate elemental lead contamination in the surface soil.
No specific measures were taken during the time of gun club operation to contain, store, treat, or
dispose of the spent bullets and shot, except for construction of soil berms in the target area.
Approximately 1,850 cubic yards of soil from the berms containing visible lead were removed from
the site in October 1987.
The proposed development of the site required several site studies, including an Environmental Impact
Report and a Preliminary Site Assessment. As a result of these studies, a determination was made that
262
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surface soil contamination by particulate elemental lead in the form of spent bullets and shot remained
in certain areas of the site.
Regulatory Perspective
The Department of Toxic Substances Control (Department) oversight was requested by the City of
Folsom to ensure that a health based soil cleanup level was achieved. The Preliminary Endangerment
Assessment (PEA) prepared by Wallace Kuhl and Associates, Inc. further characterized the site and
defined the vertical and horizontal extent of the soil contamination after initial sampling confirmed
elevated levels of lead in the soil. The PEA is an evaluation tool that assesses what remedial action
is required to protect public health and the environment. Information and determinations gained
through conducting the PEA included:
1) Site Description and History;
2) Apparent Problem;
3) Environmental Setting;
4) Sampling Activities and Requirements;
5) Human Health and Environmental Threat Assessment; and,
6) Conclusions and Recommendations.
The PEA also incorporated a description of the remedial action. The PEA presented information and
data in a standard format to allow Departmental review of the potential for lead exposure from on-site
soils.
The soil cleanup level for lead was determined for unrestricted use of the site. The type of
contamination at the Folsom Gun Club site and the land use issue that designated change to residential
development necessitated a treatment that was protective of human health. A Health Risk Assessment
was conducted to predict whether the estimated residual concentrations of lead would pose a potential
negative impact on the health of residents who would live in the development. A level of 170 ppm
residual lead for the treated soil to be placed beneath an on-site roadway was established by a
Department staff toxicologist based on risk factors to children and pregnant women, the most sensitive
receptors.
Acceptable residual soil levels at the proposed residential lots from which the contaminated soil was
excavated was determined using the U.S. EPA's Uptake/Biokinetic Model (Model) to estimate the total
lead uptake (micrograms per day) in humans, in particular for infants and young children. This
approach was developed by the U.S. EPA because there is a lack of empirical evidence for a threshold
for many of the noncarcinogenic effects of lead in infants and young children. Therefore, the use of
263
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traditional toxicity criteria (the reference dose; RfD) in assessing risk for lead is not considered
adequate by the U.S. EPA. The Model provides a method for predicting blood lead levels in infants
and children exposed to lead in multiple environmental media (air, diet, soil, indoor dust, water, etc.).
The potential exposure pathways evaluated for the health risk assessment were:
1) ingestion of soil;
2) inhalation of fugitive dust originating from site soil;
3) ingestion of homegrown vegetables and fruit; and,
4) in utero exposure as result of maternal lead intake.
The Model, which used the residual lead concentration of 77 mg/kg for the residential lots, predicted
blood lead levels in infants and children aged 0 to 7 years to be 3.89 ug/dL, which is less than the
California Department of Health Services' threshold concentration of 5.0 ug/dL. The site exposure
pathways contributing the greatest amount to blood levels in children are ingestion of homegrown
vegetables and fruit, and ingestion of soil. Based on the results of the health risk assessment, future
residents of the development will not be adversely impacted by residual concentrations of lead in site
soil.
Another regulatory issue was to determine if lead, in essentially an elemental form, constitutes a
hazardous waste. A related issue was also addressed - do lead bullets and shot meet criteria under
the Scrap Metal Exclusion? It was determined that the lead as a result of lead bullets and shot was
not generated as a hazardous waste but was a hazardous substance. The lead in the surface soil,
therefore, constituted disposal, and would have had to have been handled as a hazardous waste if it
had been excavated and disposed of off site. Therefore, any remedial activity that involved moving
the lead-contaminated soil triggered hazardous waste requirements in Title 22, California Code of
Regulations (Title 22, CCR) and procedures mandated fay the Department.
The Department is required under Title 22, CCR to implement regulations to manage hazardous
substances and wastes in order to protect the public health and the environment. In Title 22, CCR
Section 66261.24, Characteristic of Toxicity, the Total Threshold Limit Concentration (TTLC) for lead
is 1000 parts per million (ppm) or mg/kg wet-weight. The TTLC is defined in Title 22, CCR as, "the
concentration of a solubilized, extractable and nonextractable bioaccumulative or persistent toxic
substance which, if equaled or exceeded in a waste, renders the waste hazardous." Any material with
a lead concentration exceeding 1000 ppm TTLC is to be handled as a hazardous waste.
The leachability of the lead through the soil is determined by the Soluble Threshold Limit
Concentration (STLC). The STLC is an indication of how soluble a substance or compound is through
a medium. The STLC for lead is established at 5 ppm (milligrams per liter) in Title 22, CCR and
264
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defined as, "the concentration of a solubilized and extractable bioaccumulative or persistent toxic
substance which, if equaled or exceeded in a waste or waste extract...renders the waste hazardous."
The solubility test to determine the teachability is the Waste Extraction Test (WET). The WET was
designed to reproduce leaching potential in a landfill. The WET is considered an aggressive solubility
test for metals because it uses citric acid as a buffer. This tends to pull the metal out of solution and
will not necessarily reflect what transpires in non-landfill environments subjected only to rainwater.
Therefore, deionized water was substituted for the citric acid in a subsequent WET. The WET using
the citric acid buffer on soils from the site exceeded the STLC limit of 5 ppm, whereas the test using
the deionized water did not exceed the limit. Although neither test completely reflects what occurs
in the environment, a comparison of the two allowed for a site management decision based on the
results of both methods.
Another regulatory issue addressed whether or not lead bullets and shot classifies as scrap metal.
Under Section 66260.10 Title 22, CCR, "scrap metal" is defined as one or more of the following:
1) Manufactured, solid metal objects and products;
2) Metal workings, including cuttings, trimmings, stampings, grindings, shavings, and
sandings; or
3) Solid metal residues of metal production.
The definition also lists exclusions for metallic wastes that are not considered scrap metal. These
exclusions include under Section 66260.10 subsection (b)(6), "Sludges, fine powders, semi-solids, and
liquid solutions that are hazardous wastes." The argument has been made that based on the regulatory
definition, lead bullets and shot are manufactured, solid metal objects or products and therefore are
excluded from regulation as a hazardous waste. If the lead bullets and shot are found to have
disintegrated into a fine powder (defined in Section 66260.10 as, "a metal in dry, solid form having
a particle size smaller than 100 micrometers in diameter"), then based on the exclusion in subsection
(b)(6), it would not be considered scrap metal. If the lead bullets and shot are mixed with a fraction
of lead as a fine powder, then testing is required to determine whether it has any characteristics of
hazardous waste. The site soils at Folsom did not meet the criteria for scrap metal exclusion because
fines of 100 micrometers or less were extractable from the soils. The larger question of whether lead
shot meets the definition of a scrap metal is not resolved.
265
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Soil Sampling
A surface soil sampling plan was developed to assess the extent of the lead contamination. The results
of this sampling confirmed that the areas of the site containing elevated levels of paniculate elemental
lead were near the soil berms originally constructed for the purpose of intercepting spent bullets, and
in the trapshooting area that received spent shot. Concentrated sampling in these areas defined the
limits of the surface soil contamination. The following phases of sampling for characterization,
delineation, and confirmation were conducted:
Initial Sampling
The first phase of sampling took place on January 23 and 25, 1990. A total of 47 surface soil samples
were obtained over the entire site to identify areas of potentially elevated lead concentrations and to
determine background levels of lead in soil in areas of the site away from the former gun club
operations. The samples were obtained from the upper six inches of soil. Laboratory analysis of these
samples indicated that four areas of the site contained lead concentrations greater than background
levels: three former soil berm areas and the trapshooting area.
Delineation Sampling
The second phase of sampling took place on February 14, 1990, and March 7 and 19, 1990. Fifty
surface and subsurface samples from depths ranging from zero to four feet were obtained in the areas
identified by the initial sampling as containing elevated levels of paniculate elemental lead; the
delineation samples were taken to determine the lateral and vertical extent of lead-contaminated soil
in these areas.
Based on the laboratory analyses of the delineation samples, the lateral and vertical limits of elevated
levels of lead (above 170 mg/kg) were defined.
Post-Excavation Confirmation Sampling
Subsequent to delineation of the four areas of lead contamination, the contaminated soil was excavated
and stockpiled. The former soil berm areas were then resampled to confirm that the lead-contaminated
soil had been removed. When confirmation samples indicated remaining isolated areas of residual
contamination, the process was repeated — the isolated areas were excavated, and the excavated
266
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material stockpiled. Upon completion of the excavation process, confirmation sampling indicated that
the highest concentration of lead remaining in the former trapshooting and soil berm areas was 77
mg/kg.
Stockpiled Soil
The entire stockpile of lead-contaminated soil, approximately 15,000 cubic yards, was field screened
through a one-inch vibratory screen. The uncontaminated material retained on the screen (larger than
one-inch diameter) was stockpiled separately and subsequently used as backfill beneath an on-site
asphalt-concrete roadway. The finer-grained soil passing through the screen (less than one-inch in
diameter and containing the paniculate elemental lead) comprised approximately 9,000 cubic yards and
was processed in the treatment plant.
The screened soil consisted of gravel, sand and silt. Sieve analysis data revealed that the gravel
comprised approximately half of the final weight of the soil; an average of 70 percent by weight was
retained on the No. 12 sieve and an average of five percent by weight passed the No. 30 sieve.
Treatment Plant
A modified sand and gravel plant was used to treat ("wash") the lead-contaminated soil. Sand and
gravel plants operate on the principle that alluvial sand and gravel have an average specific gravity of
approximately 2 to 3 grams per cubic centimeter (g/cc). The difference in specific gravity between
the paniculate lead (11.4 g/cc) and the soil was utilized to physically concentrate, separate and remove
the lead from the soil.
The modified plant consisted of a hopper feeder above a jigging box used to capture the larger lead
slugs and shot, and two sand screws which fed material onto three stacked screens (3/4", 1/4" and
1/8"). The fine material passing the smallest screen was sent through a three-foot-diameter centrifugal
separator. The remaining material (treated soil) flowed along a drag tank until it dropped off the end
of the plant; the treated soil was "beached" from this point outward in a triangular shape onto a gently
sloping surface previously created by earthmoving equipment. The treated soil was contained at the
furthest extent of the beached area by a three- to five-foot-high soil berm. The concentrated lead in
the jigging box and centrifugal separator was removed and stored in sealed 55-gallon drums on site.
267
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The treatment plant processed approximately 20 cubic yards of soil per hour and utilized approximately
300 gallons of water per minute; the water was stored in two recirculation settling ponds, described
below.
Recirculation Ponds
The ponds were constructed using large Caterpillar scrapers by creating two trenches approximately
150 feet long by 15 feet wide. The excavated trenches were lined with 30-mil continuous plastic
sheeting to form an impermeable barrier. Approximately 200,000 gallons of water from a hydrant on
site was used to fill both ponds to a depth of approximately five to six feet.
The pond water initially became turbid with solids (silt and clay sediment), which increased its
viscosity. The increase in water viscosity made it difficult for the lead to settle in the plant. This
problem was solved by the addition of calcium chloride to the circulating water. Calcium chloride
acted as a flocculent, causing suspended fines and clay particles in the processing water to lump
together and drop out of suspension. Empirical observations in the field showed that approximately
40 pounds of calcium chloride added to the water were required per 100 yards of processed material.
When the level of settled fines in the lower pond rose to a point near the water pump intake, the fines
were either pumped out with a trash pump, or removed using a large bucket excavator. The fines
were placed against the soil berms constructed downslope from the ponds.
Results of lead analysis in water samples obtained from the recirculation ponds showed < 10 fig/1 lead
on October 8, 1990, and 46 fig/t lead on October 17, 1990. Lead concentrations in the recirculating
processing water were below the reporting limit of 10 /zg/l in four water samples taken March 4, 7,
15, and April 3, 1991.
Reconsolidation Process
Upon completion of the soil washing process, the fines from the recirculation ponds were combined
with the treated soil (reconsolidated) using a Caterpillar D8 bulldozer equipped with three four-foot-
long ripper teeth during early April, 1991. The reconsolidation process involved continuous mixing
with the bulldozer in a grid pattern for five days (42 hours). The mixing area was approximately 630
feet long by 190 to 260 feet wide.
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After mixing operations, the reconsolidated soil was sampled in place. The grid for the sample
locations was based upon a minimum of fifty samples. At each sample location, a backhoe trench
was excavated from the surface to the bottom of the reconsolidated soil, approximately three to four
feet deep. Three discrete samples were collected from the top, middle and bottom of the trench at
each sample location.
The treated soil, following the reconsolidation process, had a mean lead concentration of 181 mg/kg.
The plastic pond liner was removed from the ponds by the excavator bucket. Three soil samples were
obtained from below each of the former ponds. The test results for these samples showed lead levels
in the native soil below the former pond sites well below 170 mg/kg.
Recovered Lead
Elemental lead particles ranging in size from coarse slugs down to approximately 100 mesh were
recovered from the stockpiled soil. The recovered lead was in the form of slugs, shot and small
particles. The slugs comprised eight to ten percent of the total weight of recovered lead. Of the
remaining lead shot and particles, 98.5 percent passed the No. 8 mesh screen.
All recovered lead (slugs, shot and particles) was stored on site in covered 55-gallon drums. Twenty-
one drums were transported on May 13, 1991 to a recycling facility. The net weight of lead as
delivered was 31,970 pounds.
Cost
The total cost for the project was approximately $1,000,000, including excavation, field screening,
recirculation pond construction, soil treatment and reconsolidation, and placement of the treated soil
beneath the roadway.
Acknowledgments
The authors would like to acknowledge the contributions of Eric Hubbard of Wallace Kuhl and
Associates, Inc., who prepared much of the Preliminary Endangerment Assessment, Western
Environmental Science and Technology (WEST), who coordinated the treatment operations, Lee R.
Shull, Ph.D. of Western Environmental Health Associates, who prepared the health risk assessment,
and Richard Brausch of the California State Department of Toxic Substances Control, who contributed
to the scrap metal exclusion analysis.
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Mr. Markku Aaltonen
EKOKEM Limited
P.O.BOX 181
SF-11101 RHHIMAKI
FINLAND
IMPROVEMENTS IN THE CONVENTIONAL HIGH TEMPERATURE
ROTARY KDLN INCINERATION TECHNOLOGY
1. INTRODUCTION
Ekokem Ltd operates two rotary kiln incinerators for hazardous wastes in
Finland. Since 1984, when the first kiln started, the company has been
developing the technology with Outokumpu Ecoenergy, a Finnish
engineering firm. As a result of this co-operation, a second kiln was
introduced in 1991.
The most significant difference compared to similar kilns, is the extremely
high temperature used in a rotary loin, 1.300 - 1.400 ' C (2.400 - 2.600 F)
This results in several advantages: high combustion efficiency, slag
vitrification and increased capacity. Refractory lining will normally be
damaged when using increased temperature. This problem has been solved
by installing a special cooling system around the kiln.
Another common source of disturbance in rotary kiln technology is
inhomogeneity of waste feed. A shredder and feed homogenizer have been
designed which allow for more solid organic material to be fed, as well as
decreasing the need for auxiliary fuel (waste oil or solvents).
270
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2. INCINERATION ONE H
Ekokem designed a new rotary kiln incinerator which has been in operation
since April 1991. An activated carbon injection system with additional bag
filter was installed in October 1992. Compared to the original incinerator
this system has several new features which give better result in combustion,
gas cleaning and solid material pretreatment.
The capacity of the new line is 25.000 tonnes/a of organic waste and 6.000
tonnes/a of waste water. The net value of the investment was
approximately 30 MUSD.
Ekokem has created its own philosophy in respect of hazardous waste
combustion, where:
the temperature in the rotary kiln is extremely high (1.300 -
1.400 °C)
waste is homogenized and fed uniformly to the kiln
after burning chamber is designed to ensure complete
mixing and sufficient retention time for the whole
gas stream
the gas cleaning technology is the best available to
reach the extremely tight emission limits
The advantages of this method of operation are:
to reach the highest possible combustion efficiency
to have an insoluble vitreous slag resulting in lower
costs of landfilling or utilization
increased capacity of the kiln
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2.1 The Kiln Cooling System
If a temperature of < 1.100 °C is applied in the kiln, the after burning
chamber must be operated at a higher temperature using auxiliary fuel.
These are normal operational conditions in most European incinerators.
There are some disadvantages, such as, lower combustion efficiency in the
kiln and the fact that some types of waste (for example PCB) cannot be
incinerated efficiently. Also heavy metals will not evaporate from the slag.
Moreover, the slag is not melted and a protective layer of molten slag is not
formed.
Ekokem operates both kilns at 1.300 - 1.400 °C temperature made possible
only by a special cooling system.
External cooling of the kiln has been in succesful operation at Ekokem
since October 1987. The improvements have been the following:
- Lifetime of refractory lining has more than doubled
- Capacity has increased 10 - 20 % on an annual basis
- Operating hours per year have increased
- The thickness of refractory lining can be reduced
- PCB waste can be incinerated due to increased temperature
- Heavy metals such as lead are totally evaporated from the slag
Steel barrels are oxidized and dissolved
- Thermal stress on refractory lining and shell is reduced
The main objective of the cooling system is to keep all parts of the kiln
shell at a constant temperature. Cooling must also be maintained during
power failures. Inside the refractory lining, the formation of a layer of solid
and high viscous slag takes place, which protects the lining from erosion
and corrosion.
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An important factor of the control of kiln operation is the understanding of
molten slag chemistry. The viscosity and other properties can be influenced
by proper feed and additives thereby avoiding disturbances caused by
uncontrolled slag properties.
The quality of slag is shown in Table 1. The low solubility means that the
material is not classified hazardous or toxic and it can be used in
construction of roads, etc.
2.2 Pre-Treatment and Feed to the Kiln
Pre-treatment starts with the reception of waste and a rigid laboratory
control on incoming materials. Waste oil and oily wastes should be treated
to separate oil, water, paste and solid fractions and then individually fed to
the incinerator. Chlorinated solvents should be separated from normal
solvents.
Barrels form the most difficult handling problem in the pre-treatment area.
The main difficulties are the disposal of empty barrels and barrels that
cannot be emptied because of solidified content or risk of polymerization of
the contents.
The trend is towards a highly automated barrel handling system which
meets the requirements of the working environment and fire safety
regulations. Handling includes a shredder system for the steel barrels which
allows the steel scrap to be added to the bulk material.
273
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The contents of the barrel are separated into different fractions to be fed
separately to the incineration line. In the future, feeding of complete barrels
will virtually be unknown, with the probable exception of infectious waste
and some special wastes.
The bulk material is usually fed to the incinerator with a grab crane,
typically in 1 ton batches. Even though the bulk material is well blended,
the batch introduced to the kiln will cause variations in the oxygen content
of the flue gases and consequently problems in CO emissions. A solid waste
feed homogenizer has been installed resulting in stable combustion and a
better control of emissions. Table 2 shows emission standards for both the
Ekokem kilns.
The patented cooling system has already been adapted to several European
rotary kilns.
Table 1
Slag Suitability After EI'A-Tcst
El'A limits ing.!
Il.i
A*
Cd
Cr
1'b
Sc
AH
UK
100
s
1
s
s
1
s
0,2
F.kokcm slag ing/I
0,2 - 0,3
0,005 - 0.018
0,001 - 0,004
0,001 - 0,004
0.01 - 0,03
< 0.01
< 0.002
< 0.0005
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'I able 2
Limit Values for Incineration Lines 1 & 2 (dry, 12 % O2)
Dust mg/ni3
HC1 nig/in3
HF mg/m3
CO mg/m3
Cx Hj. mg/m3
Hg //g/m3
TCDD-ekv ng/m3
Incinerator 1
30
50
2
70
20
50
1,0
Incinerator 2
10
20
2
70
20
50(I)
1,0 *>
(1) Obligation to study the possibility to reach value 30 ,/ Obligation to study the possibility to reach value 0,1 ng/m3
275
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EVALUATION OF GROUTING TECHNOLOGY! DOE PERSPECTIVE
by
Dr. W. Roberds
Colder Associates Inc., 4104 148th Ave NE, Redmond WA 98052; (206)883-0777
and
Dr. A. DuCharme
Sandia National Laboratories, Org 6301, POBox 5800, Albuquerque NM 87185; (505)844-5571
ABSTRACT The US Department of Energy (DOE) must make a variety of decisions within their
environmental management (EM) program regarding (1) development and transfer of improved
EM technologies and (2) application of the optimum EM technologies at specific sites. To assist
in this decision-making process, a methodology has been developed for evaluating EM
technologies in terms of (1) the degree to which they would accomplish specific EM activities and
satisfy specific requirements, under various conditions, if they were available, and (2) the costs
and risks (if any) associated with their becoming available. For demonstration purposes, this
methodology was applied to (1) the preliminary evaluation of the generic application of a
Ukrainian clay-based grouting technology to the DOE complex, and (2) the detailed evaluation
of the specific application of a French silicon-based grouting technology to DOE's underground
storage tanks at Hanford, Washington. Based on these evaluations, justifiable recommendations
regarding further development and transfer of these technologies were made.
INTRODUCTION
The US Department of Energy (DOE) manages an extensive complex of facilities throughout the
United States which are concerned with radioactive and hazardous wastes. DOE is responsible
for environmental management (EM) of these facilities. In this role, they must make significant
decisions regarding (1) application of the optimum available EM technologies at each site, and
(2) improvements in available EM technologies. The potential consequences of poor decisions
in these areas include unnecessary hazards (short- and long-term), expense, and/or delays, as
well as possibly inadequate performance. Hence, a methodology is needed to help ensure that
appropriate decisions are made. As discussed herein, this methodology consists essentially of
evaluating EM technologies with respect to specific DOE needs, both for individual facilities and
the complex as a whole.
The context of the methodology within the DOE EM program is first discussed. The application
of the methodology to the evaluation of two grouting technologies is then presented.
DOE EM PROGRAM
The US Department of Energy (DOE) is responsible for environmental management (EM),
consisting of waste management (WM) and environmental restoration (ER), at a number of
facilities throughout the US.
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EM Activities - The various types of EM activities have been identified through a simple EM
system process chart, as illustrated in Figure 1. Although broadly defined, this chart is believed
to represent a comprehensive set of EM activities (DuCharme et al, 1992a):
Waste
Characterization
Waste
Treatment
WM
Waste
Generation/
Minimization
Waste
Trasportation/
Storage
Waste
Disposal
Characterization
(Secondary Wastes)
ER
Monitoring
In-Situ Treatment
or Site Waste
Removal
In-Situ
Containment
(adapted from DuCharme et al, 1992a)
Figure 1 DOE EM Activities
Waste Management (WM) - An initial waste stream is generated through various
processes. During generation, the amount of waste can be minimized through specific
procedures. The waste should be characterized and can possibly be treated, where
treatment may include further waste minimization and require additional post-treatment
characterization. Such treatment may be conducted off-site, thus requiring transportation
of the waste to the treatment facility. Whether treated or not, the waste must ultimately
be transported to a disposal facility. The disposal facility, in turn, must be characterized
prior to disposal and monitored after disposal.
Environmental Restoration (ER) - If an operating disposal facility is found by monitoring
to not perform adequately, or if an existing contaminated site (e.g., a closed disposal
"facility") is found by characterization to not perform adequately, it can be: (1) remediated
(cleaned up) to various degrees by in situ treatment or by removal of the contaminated
277
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materials; and/or (2) mitigated (contained). Containment may: (1) precede remediation,
either as a stop gap measure until remediation can be conducted or to prevent further
contamination during the remediation process; or (2) follow remediation if the
remediation process is incomplete and residual contamination remains on-site. If
mitigated, then monitoring must continue to ensure adequate performance, with
subsequent additional mitigation or remediation possible. If remediated, a secondary
waste stream is generated, which must be characterized, treated, transported and
disposed of in similar ways as the primary waste stream.
BM Conditions - EM activities will be conducted under specific conditions at each site. These
conditions have been broadly but comprehensively categorized as follows (DuCharme et al,
1992a):
• Waste
specific types of waste (i.e., contaminants);
amount of each type (e.g., in terms of an operating period and rate of newly
generated wastes, and/or in terms of current concentrations and volumes of
previously disposed wastes); and
waste form (e.g., dissolved in groundwater, packaged in barrels, vitrified, etc.).
• Site (see Figure 2)
waste environment;
transport characteristics from the waste to potential receptors, which in turn are
a function of the engineered barriers, the geology, the geohydrology, and the
climate; and
potential receptors, including distance and demographics.
* Waste-site relationship (configuration, Figure 2)
release rates; and
pathways.
• Infrastructure (framework within which the waste/site system operates)
regulatory;
institutional; and
public.
EM Program Requirements - EM activities must be conducted within specific requirements:
• Technical - Functional requirements (eg, minimum capacity) may be established for
specific activities (eg, waste disposal). Similarly, performance requirements (eg, maximum
allowable dose) may be established for other activities (eg, in situ containment). In
addition, cost and schedule, as well as safety, will generally be of concern, and may be
mandated (eg, by negotiated agreement).
• Institutional - As policy, there will be a minimum acceptable level of confidence, either
implied or stated, that the technical requirements will be satisfied. This requires high
confidence that the proposed approach for conducting the EM activities will work as
anticipated, which in turn suggests high confidence that the technologies involved will
278
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Meteorology
Demographics
Form
Concentration
Volume
(adapted from DuCharme et al, 1992a)
Figure 2 ER Site Conditions
be available when needed and moreover will be accepted (eg, by the regulators and the
public).
EM Program Decisions - A wide range of technologies are currently available for conducting the
various EM activities and satisfying the specified requirements. Improvements on these
technologies, as well as new innovative technologies, can be developed and/or transferred (if
necessary), and thus become available in the future. Significant decisions must be made by DOE
regarding: (1) programs for developing and/or transferring EM technologies; and (2) technologies
for conducting EM activities at specific sites.
Technology Attribtltes - The various technologies can accomplish specific activities and satisfy
specific requirements to various degrees, depending on the specific conditions involved. For
example, advanced incineration can be used to treat primary organic wastes, thereby reducing
the volume for disposal, while meeting air emission requirements. Each technology has a specific
set of relevant "attributes", which include:
• effectiveness in satisfying specific activities/requirements under various conditions;
• application cost (fixed and variable);
• rate of application;
• hazards associated with its application; and
• acceptability (ie, to regulatory agencies, institutions, public, etc.) of application. "
If the technology is not yet available, then the cost and time associated with it becoming available
(eg, through research and development, and/or transfer), and the likelihood of it ever becoming
279
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available, must also be considered. The likelihood of future availability is a function of the
current status of developmenl/transfer, the plans for completing development/transfer, and
potential problems associated with developmenl/transfer.
Evaluation Process - Decisions on technologies for site specific applications and for
developmenl/transfer programs can be made based on comparative evaluations of their attributes
with those of "base case" technologies, in conjunction with tradeoffs made among the attributes.
For example, one technology might be preferred over another even though it is less effective
because it can be applied faster and cheaper. As illustrated in Figure 3, the evaluation approach
consists of first screening the technologies with respect to applicability to specified EM
activities/conditions. The potentially applicable technologies are then comparatively evaluated
against Base Case alternatives in terms of their relative effectiveness in solving the specific EM
problems, and the costs, schedule, safety issues and acceptability issues associated with their
application, assuming that they are available (ie, fully developed and transferred). These
comparative evaluations can then be combined with value judgements regarding tradeoffs among
the various factors to establish a rating for the specific application of that technology. If the
application rating is positive, the technology (once available) would be preferred to the Base Case
alternative. If the application rating is not positive, the technology would not be preferred to the
Base Case alternative, regardless of availability, so that any remaining developmenl/transfer
should not be carried out. However, if the technology is preferred over the Base Case alternative
but is not yet available, then the likelihood of successfully completing development and transfer
of the technology, and the associated cost and schedule, must also be considered. These
evaluations can then be combined with the application rating, the priority of that application,
and value judgements regarding tradeoffs among the various factors to establish an overall rating
for the development, transfer, and application of the technology. In this evaluation, the cost of
making such a technology available should not necessarily be borne by any one site, but spread
among all those sites where it would be used. Based on the overall rating, a decision would be
made whether to continue development and transfer of a specific technology.
International Program - Within EM and complementary to other programs in accomplishing
DOE's EM mission, DOE instituted the International Program Division (IPD), previously called
International Technology Exchange Program (ITEP), with the following primary goals:
• Import - Transfer foreign EM technologies which are more effective ("better"), cheaper,
faster, safer or more acceptable to apply to DOE's EM activities/conditions/requirements
than those technologies currently available in the US.
• Export - Identify foreign EM needs (ie, specific site activities, with associated conditions
and requirements) for which currently available US technologies are more effective
("better1^, cheaper, faster, safer or more acceptable to apply than those foreign
technologies currently available (ie, market opportunities).
Within IPD/ITEP, a methodology has been developed for definitively evaluating candidate
technologies, consistent with the above evaluation process (DuCharme et al, 1992a). Such
evaluations are done at two levels: (1) preliminary evaluations with respect to generic, system-
wide applications for screening a large number of candidates for potential development (if
necessary) and transfer; and (2) detailed evaluations with respect to site-specific applications.
280
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Specific
WM/ER Problem
i
Potential
Application to Specified
WM/ER Activities/
Conditions
Base Case
Alternative
Technology
Cost-
Schedule*
Safety
Issues *
Acceptability
Issues*
Effectiveness*
Value
Judgements
(Tradeoffs)
Do not apply or
consider further
Likelihood of
Success**
Value
Judgements
(Tradeoffs)
Continue /
Development/
Transfer
(Cancel
Development/
Transfer
Attributes of application of candidate technology if available (ie., fully developed and
transferred), compared to application of Base Case alternative technology.
r For full development and transfer of candidate technology.
(adapted from DuCharme et al, 1992a)
Figure 3 Comparative Evaluation of EM Technologies
EnviroTRADE - Ultimately, the site-specific evaluations will be accomplished through a
computerized relational data base (ie, EnviroTRADE) which is being developed within IPD/ITEP
281
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by Sandia National Laboratories for DOE (Harrington and Harlan, 1992). EnviroTRADE will
consist of the following compatible modules:
• World-wide EM needs data base, describing the relevant conditions and requirements for
various EM activities at sites around the world (including the responsible parties),
categorized by country;
• World-wide EM technology data base, describing the relevant attributes of technologies
(including application parameters, availability and contacts); and
• Decision module for matching EM technologies and EM needs, either to identify and rank
appropriate technologies for user-specified needs, or to locate potential applications (ie,
markets) for user-specified technologies.
GROUTING TECHNOLOGY EVALUATION
In order to demonstrate the use of the methodology for evaluating EM technologies and thereby
assisting DOE to make rational and informed decisions regarding (1) development and transfer
of foreign technologies and (2) application of technologies at specific sites, similar but different
technologies have been evaluated at various levels:
Ukrainian clav-based groutine technology is adequately described in other papers
(Spickelmier, 1992; Verma, 1992). Its attributes are briefly summarized, and then the
technology is evaluated in a preliminary fashion for generic applications to determine
whether its development and transfer should continue.
• A. French silicon-based gel grouting technology is described. It is evaluated in a detailed
fashion with respect to application at a specific site, ie, to provide containment of the
single shell underground tank wastes at Hanford, Washington, to determine whether it
should be considered further for this application.
Grouting in general can be used to create a low permeability barrier for in situ containment, eg,
prior to remediation as a stop gap measure, during remediation to prevent transport of mobilized
wastes, or for the long-term. Grouting can also be used to redirect and concentrate a
contaminant plume for remediation. The resulting seals are applicable to containment of various
contaminants from basins/ponds, storage tanks, trenches/cribs, containerized wastes, and
leaks/spills.
UKRAINIAN CLAY-BASED GROUTING TECHNOLOGY
A specific clay-based grout which may provide improved containment has been identified
through ITEP puCharme et al, 1992a and b). The clay-based grout was developed by the
Ukrainian company SPETSTAMPONAZHGEOLOGIA (STG), which translates to "grouting and
geological enterprise". This grouting technology can and has been applied to a variety of
problems, especially to provide relatively impermeable barriers (eg, during construction of shafts)
in fractured or karstic water-bearing rocks. Of particular interest is its potential application in
282
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providing a barrier to contain hazardous wastes at similar sites managed by DOE.
Properties - The clay-based grout consists of the following components:
• 89% clay slurry at densities up to 87 pcf, which in turn consists of kaolin (or possibly illite
if kaolin is unavailable) mixed with water;
• less than 10% cement or processed tailings; and
• 1 to 2% of structure-forming reagents, such as sodium silicate.
The resulting grout is reported to have the following beneficial properties:
« chemically stable in a variety of conditions;
• long-term pliability so that small ground displacements can be accommodated without
compromising barrier characteristics;
• low shrinkage and erodability so that barrier characteristics are not compromised by
changes in groundwater conditions;
• non-toxic; and
• low cost relative to other chemical- or cement-based grouts.
Evaluation - The clay-based grout is very viscous, and thus can only be applied effectively in
"open" geologic systems, ie, fractured or karstic rock. In such cases, compared to other chemical-
or cement-based grouts, application of the clay-based grout is believed to have the following
attributes, based on preliminary subjective evaluations:
• more effective because it is more pliable and long-lasting;
• cheaper;
• similar rate of application;
• similar safety issues; and
• more acceptable (once transferred and demonstrated) due to its better performance and
use of natural, geologic, non-toxic materials.
Due to a lack of experience with this technology in the US, however, there are significant
uncertainties in these attributes, especially in the range of site and waste conditions for which
the grout would be effective and the duration of such effectiveness. Such issues must be
adequately resolved, eg, by demonstration testing in the US, before development of the
technology can be considered complete and it can be used for DOE projects. Such a
demonstration has been proposed, and has been estimated to take on the order of two years to
complete. In addition to completing technical development, the technology must also be
transferred to the US before it is available for application. This has been at least partially effected
by STG forming a joint venture with Morrison-Knudsen to market the technology in the US.
Recommendation - Based on the preliminary evaluation of the clay-based grouting technology,
it appears that it should be considered further, once it becomes available, where containment in
"open" geologic systems is needed at DOE sites.
FRENCH SILICON-BASED GROUTING TECHNOLOGY
A specific inorganic, silicon-based grout which may provide improved containment has also been
identified through ITEP (DuCharme et al, 1992a and b). The silicon-based grout ("KLEBOGEL")
was developed by the French company Societe Franchise Hoecsht (SFH). This grouting
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technology has been applied to a variety of problems, primarily to provide additional strength
for granular soils during excavation, but it has reportedly also been used successfully in oil
reservoir secondary recovery to plug a permeable zone around an oil reservoir, under extreme
conditions (60-80°C and 1000m depth). It is now being considered as a means to provide a
barrier to contain hazardous wastes around underground storage tanks (USTs) at Hanford
Washington for Westinghouse Hanford Company (WHQ, a DOE contractor.
Evaluation Process - The detailed evaluation of the silicon-based grout for this specific
application involved significant interactions between the evaluators and the technology owner
(ie, SFH), and between the evaluators and the potential users (ie, DO^VVHC). As illustrated in
Figure 4, this was accomplished through the following steps:
SFH -*-
Detailed
Description of
Attributes of
Silicon-based
Grouting
Technology
Technical
Experts
(Including
Operators)
Description of
Hanford-UST
Technology
Requirements
WHO
Review of
Description of
Attributes of
Silicon-based
Grouting
Technology
Description of
Attributes of
Hanford-UST
Base Case
Technology
Comparative Evaluation of Silicon-based
Grouting Technology (w.r.L Base Case
Technology) - Tradeoffs among
Differences in Attributes
SFH-*-
WHO4-
Bring SFH and
WHO Together
to Pursue
Application of
Silicon-based
Grouting
Technology to
Hanford-UST
Silicon-
based Grouting
Technology
Preferred?
Terminate
Further
Consideration
of Application of
Silicon-based
Grouting
Technology to
Hanfard-DST
UST - underground storage tanks
WHO - Westinghouse Hanford Company, DOE contractor at Hanford, Washington
SFH - Societd Francase Hoechst, French developer of silicon-based grouting technoloav
(adapted from DuCharme et al, 1992a) ay
Figure 4 Detailed Site-Specific Evaluation of French Silicon-Based Grouting Technology
1. The list of relevant technology attributes was sent to the technology developers (ie SFH)
for them to fill out
2. Technical experts (including operators) reviewed the foreign participants' description and
assessment of their technology's attributes. These reviews were then resolved with the
foreign participants.
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3. The end users (ie, WHC) identified and described (in similar terms) their specific
technology requirements for the USTs, and the domestic base case for comparison.
4. A quantitative comparative evaluation (i.e., differences in attributes) of the silicon-based
grouting technology with respect to the base case technology for the Hanford USTs was
conducted, involving WHC in determining appropriate tradeoffs among the attributes.
5. If the evaluation of the silicon-based grouting technology is favorable (ie, it is potentially
better, safer, cheaper, faster, and/or more acceptable compared to the base case
technology), then SFH will be brought together with WHC to pursue application of their
technology to the Hanford USTs. Otherwise, application of the silicon-based grouting
technology would not be pursued further for the Hanford USTs, although it may still be
applicable for USTs at other DOE sites or for other facilities (eg, cribs, trenches, or ponds)
at various sites (including Hanford).
Generic Properties - The silicon-based grout consists of various portions of sodium silicate, "silica
sol" (a dispersive suspension of very fine silica particles), "glyfix" (acid-based hardener) and tap
water. They produce an amorphous, silicon-dioxide gel, with about 5-10% solids. The recipe is
proprietary and confidential, and can be varied on-site to suit observed conditions. As
demonstrated in the laboratory, the resulting grout has low permeability (ie, less than 10"9 m/s),
is very flexible, has low shrinkage (even under high temperatures) and is chemically stable, as
long as it is not allowed to dry out. The materials are non-toxic and EPA/NEPA approved
(although for other purposes). Prior to setting, the grout has very low viscosity (ie, 5 cPoise,
similar to water), which allows it to be injected in relatively low permeability ground (including
very fine sands); conceptually, grouting in highly permeable ground may require a first stage
grouting using fast sets or more coarse, viscous types of grout (eg, bentonite). The viscosity
increases rapidly at setting (to an amorphous gel). The setting time can be controlled over a wide
range (from minutes up to 2 days), in order to achieve proper penetration during injection, by
changing the mixture. The cost of the grout material is a function of the mixture, which in turn
is determined by the desired setting time. A fast set mix (up to 2 hours) does not include silica
sol and costs about $l/gal, whereas a slow set mix (up to 2 days) includes silica sol and costs
about $2/gal.
Generic Procedures - Access and equipment for drilling boreholes, and mixing and injecting
grout on site are necessary. Boreholes are drilled around and possibly below the site at an
appropriate spacing. These boreholes must be sufficiently stable and porous to allow subsequent
grout injection, and spaced closely enough to ensure adequate overlap. The thickness and
continuity of the barrier will be a function of borehole spacing and grout penetration
characteristics. For lateral containment, the boreholes are vertical whereas for vertical
containment (eg, below tanks), the boreholes must be inclined or even horizontal. Such inclined
or horizontal boreholes are typically much more difficult to drill and especially stabilize. A
promising technique for drilling horizontal boreholes below the site is "micro-tunnelling". It
should be noted that drilling will produce secondary wastes (contaminated soil) which must be
disposed of.
The grout is mixed per specification (proprietary and confidential) in a standard batch plant, and
injected into specific zones of the boreholes. The penetration distance of the grout into the
ground around a borehole is a function primarily of the following:
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• Grout Viscosity - As previously noted, the viscosity of the grout is initially very low until
it sets, at which point it increases rapidly and penetration effectively ceases; hence, the
penetration distance is a function of the setting time, which can be varied over a wide
range. Injection conditions (eg, increased temperature, dissolved organics, aluminates and
salt content) may modify the setting time.
• Ground Permeability - The ground must be sufficiently permeable (ie, more permeable
than clay) to allow adequate grout penetration at injection pressures below those which
cause hydraulic fracturing, and yet not too permeable (ie, less permeable than gravel)
which would cause excessive grout loss. If the ground is too permeable (ie, >10"3m/s),
then a first stage of grouting with bentonite cement or clay suspension, for example, may
be necessary. The permeability of the ground will be a function of a variety of factors,
including the moisture content in the vadose zone. Variability in soil or moisture
conditions can cause preferential penetration, resulting in incomplete barriers. Similarly,
injection in the saturated zone requires water displacement, which may be incomplete,
and may result in dilution of the grout
• Injection Pressure - The injection pressure should be maintained below that which would
cause hydraulic fracturing.
The general penetration characteristics of the grout are known to be relatively good from "soil
consolidation" applications, although uniform penetration is not as important an issue in that
case. It is anticipated that grout penetration of several meters can be obtained with an
appropriate mix.
In order to be effective, the grouted zone must be continuous across the potential contaminant
transport paths and maintain a low permeability (over the required time frame). Hence, the
resulting barrier must be verified and possibly monitored with time. During injection, this might
be done by monitoring injection pressures and volumes. After injection, this might be done by
geophysical testing, eg:
• by ground penetrating radar in the grout holes or in nearby monitoring wells; and/or
• by DC resistivity surveys using sensors embedded in the grout holes
o for cross-hole analyses in the plane of the barrier, and
o for borehole-to-surface analyses across the barrier at various locations, although
this might not be appropriate for horizontal barriers below a site.
Generic Issues - Grouting can be used in ground which is sufficiently permeable to achieve
adequate penetration (eg, silty fine sands through coarse sands), although it may be difficult to
drill stable open holes in such ground especially if not vertical However, the sealant may not
be chemically compatible with all wastes or site conditions. Also, uniform penetration may be
difficult to achieve in heterogeneous site conditions (ie, soils, moisture, stresses), although two-
stage grouting might be effective. It may be difficult under any conditions to install and verify
a continuous grouted zone over large areas, especially below a site.
The specific technical issues associated with the generic application of the silicon-based grouting
technology to containment of hazardous wastes include:
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• Horizontal Drilling - Although vertical drilling procedures are well established, horizontal
drilling techniques (including micro-tunneling) have not been applied in contaminated
granular soils. Hence, there is a question whether stable horizontal grout holes can be
drilled. This is a generic grouting issue, rather than specific to the silicon-based grout
• Injection Conditions - The penetration distance for specific site conditions is uncertain
until field-tested. Similarly, the uniformity of penetration in heterogeneous conditions (ie,
relating to soils, moisture/water, and stress) is also unknown. Again, these are generic
grouting issues, rather than specific to the silicon-based grouting technology. However,
the effects of various injection conditions (eg, presence of non-neutral pH, dissolved
organics, aluminates and/or salts) on the gelation process have not yet been determined.
Adverse injection conditions might be modified by neutralizing (eg, with other chemicals)
or removing (eg, by sweeping with deionized water), although this might mobilize
existing contamination.
• Verification - The geophysical methods required for verification have not yet been tested
on the grout. Again, this is a generic grouting issue, rather than specific to the silicon-
based grouting technology.
• Long-term Integrity - The potential chemical reactions of the grout with various wastes
and injection conditions have not yet been determined. Although the grout properties,
both short-term (including setting times) and long-term, are anticipated to be good, based
on general chemical stability considerations, they may be affected by the following: (1)
interactions with the waste, either during injection or subsequently; (2) biodegradation
in the vadose zone; (3) dehydration; and (4) other chemical-physical reactions (eg,
diffusion). For example:
o If the site is highly acidic or alkaline, the gelation process* could be affected or the
gel could dissolve over time.
o Water soluble organics might diffuse into the gel, or be contained within the gel
if not displaced during injection, and the gel might then be subject to
biodegradation.
o The gel might diffuse ionically into very low salt content water over time.
o The gel might dissipate if evaporation is possible, although this is considered to
be a very slow process at the depths of interest
o The characteristics might change with time if subject to hydrolysis (eg, due to
radiation).
o The gel may be affected by changes in temperature, although based on limited
testing such effects (eg, shrinkage) are not significant for moderate changes in
temperature and as long as evaporation does not occur. High temperatures affect
the setting time, but apparently not the other properties.
o Cations may react with the silicates to form salts, although if the salts are formed
on the outer boundary only, they may be beneficial and inhibit any dissolution
of the gel with time.
o The presence of aluminates, caustic soda, sodium hydroxide, or potassium oxide,
for example, during injection may have significant negative effects.
Availability - The issues identified above must be adequately resolved before development can
be considered complete.
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SFH, which is a subsidiary of Hoechst AG (Germany), has developed the silicon-based grout
mixture (KLEBOGEL) and considers it to be proprietary and confidential. Hoechst AG also has
an American subsidiary, Hoechst Celanese Co. in Charlotte NC, which is thus affiliated with SFH.
SFH has expressed the desire to work with DOE. Hence, transfer of the technology to the US
should pose few problems.
No special equipment or expertise is needed for installation, so that a competitive environment
exists for contractor services. Special contractors may be needed, however, for drilling horizontal
grout holes and for geophysical verification.
Generic Alternatives - The alternative to KLEBOGEL is other clay-, paraffin-, chemical- or
cement-based grouts. Depending on the specific grout being compared, KLEBOGEL is generally:
more effective in reducing permeability (due to its low viscosity and extremely small particle size,
which allows greater penetration) although it may be less stable over the long-term; more costly;
possibly less acceptable, although it is NEPA-approved, due to long-term integrity issues; and
equally fast and safe to apply.
Hanford USTs - The DOE has 334 USTs for storing radioactive and hazardous wastes at their
operations across the US, with 149 single shell tanks (SSTs) and 28 double shell tanks at Hanford.
A total of 79 of these tanks, 66 of which are located at Hanford, are either known or are assumed
to leak, thereby contaminating the soil and groundwater. In addition to the USTs, other facilities
(eg, cribs, piping and trenches), either at Hanford or elsewhere (eg, INEL), experience similar
problems.
The Hanford SSTs are single shell reinforced concrete with carbon steel liners, which are of
various dimensions and buried at shallow depth. Some of them have corroded and otherwise
deteriorated over the years to the point that they are now leaking their contents into the
subsurface. The contents are liquid mixed wastes, which were relatively well known at the time
of placement (due to controlled procedures), with the possible exception of some additional
undocumented solvents. However, over time, (1) the supernates were pumped off, but not
characterized, so that some wastes may have been selectively removed, (2) water was added
(sometimes many 10,000s of gallons) when the contents leaked, possibly removing the more
soluble wastes, and (3) chemical reactions have occurred, changing the remaining wastes. For
example, several tanks are of special concern: one tank has high heat, so that 8000-10000 gallons
of water are added per month for cooling, which presumably evaporates; one tank experiences
hydrogen gas buildup, which vents (or "burps"); and another gas has relatively high
concentrations of ferrocyanide which (if high enough) could be explosive.
The subsurface consists primarily of more than 100 feet of permeable soils (sands and gravels
with some fines), overlying fractured basalt. The soil around and to some depth (about 8 feet)
below the tanks was excavated and reworked during tank construction. The groundwater is
relatively deep (about 200 feet), with a significant gradient towards the Columbia River several
miles away. Near the tanks, the pH is generally somewhat alkaline (pH of 8-10), with elevated
temperatures (up to 60-75°C). Below leaking tanks, there is a vertical plume of contaminants,
extending to various depths depending on the extent of leakage but generally contained within
the vadose zone.
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Requirements for Hanford USTs - The Hanford USTs are to be totally remediated according to
a specific schedule, per the Hanford Federal Facility Agreement and Consent Order (ie, the "Tri-
Party Agreement - TPA"). In the TPA, the DOE has committed to a demonstration of a full-scale
closure method for the USTs by 2004. This will require the following activities: (1)
characterization of waste, tanks, and the site; (2) treatment and disposal, either insitu or retrieval;
and (3) site closure and monitoring, depending on whether any wastes remain in-place. Options
for insitu treatmeni/disposal consist of stabilization, grouting or in situ vitrification, all of which
would result in residual wastes in-place when closed. Options for retrieval and
treatmeni/disposal include mechanical excavation or hydraulic sluicing followed by various
treatment/disposal options, which may result in mobilization of wastes during removal and some
residual wastes in-place when closed. Waste separation techniques could be implemented as part
of treatment, to reduce the amount of wastes to be disposed of.
Functional requirements for remediation are currently being developed (Rouse et al, 1992; Boomer
et al, 1990). The primary performance requirements for the technology include occupational
safety (e.g., dose), public safety (e.g., dose), and groundwater protection (e.g., concentrations).
The long-term performance requirements are currently being considered for a period of 300-1000
years after closure.
Base Case Technology for Hanford USTs - Consistent with the specified requirements, the
reference base case technology is as follows:
• Removal of the wastes within the tanks by hydraulic sluicing followed by treatment and
disposal. Treatment and disposal consist of mixing the wastes with cementitious grout
to stabilize it, and placing the grout in vaults in the 200 Area.
• No subsurface containment is currently planned at the tank sites, because all of the waste
is supposed to be removed. However, following treatmeni/disposal, the site would be
closed per RCRA requirements (ie, an engineered cover), unless complete remediation has
been effected and verified.
Potential Application of Technology to Hanford USTs - The candidate technology, as described
above, can be applied to help satisfy the Hanford UST requirements by enhancing specific
treatmeni/disposal options, as well as closure. Specifically, the silicon-based grouting technology
can be applied to the following areas:
• Retrieval and Treatment/Disposal - Create barrier below site to reduce leakage into the
groundwater to acceptable levels, during retrieval (especially hydraulically). Such a
barrier is an additional feature, since none is currently contemplated, and might make the
hydraulic retrieval option much more attractive. Such a barrier could incorporate a sump
to collect and remove any contaminants. ,
• In Situ Treatment/Disposal Options - Create barrier below site to reduce leakage into the
groundwater to acceptable levels, both during and after treatment During treatment,
such a barrier is an additional feature, since none is currently contemplated. Similar to
above, such a barrier could incorporate a sump to collect and remove any contaminants.
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• Site Closure - If residual wastes remain in-place from retrieval and treatment/disposal,
then the site must be closed as a landfill Similarly, if the in situ treatment/disposal option
is adopted, then the site must be closed as a landfill, assuming that residual wastes will
remain in-place. In either case, a barrier below the site will supplement a cover to reduce
leakage into the groundwater to acceptable levels. Conversely, if no residual wastes
remain in-place (above the potential subsurface barrier), then the subsurface barrier
would not contribute to meeting system performance requirements, and would be
unnecessary.
Concerns with the base case (or any other) technology include increased waste volume (including
secondary waste such as drill cuttings or leachate) and increased mobilization of waste (eg, due
to drilling fluid), as well as other aspects of short- and long-term performance.
Application Costs - The primary cost components for application of the silicon-based grouting
technology are the material costs and the drilling costs. These and the total costs have been
estimated for a bowl-shaped subsurface barrier with a nominal diameter of 75 feet and a nominal
depth of 50 feet (ie, similar to a barrier surrounding a typical individual tank at Hanford), as
illustrated in Figure 5, as a function of borehole spacing and grout type (ie, fast or slow set),
based on the following assumptions:
^ 05
tn .2
O *5
O &
3.2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
material fast ($1/gal)
drilling ($250/lf)
0 10 20
Borehole Spacing, s (ft)
(adapted from DuCharme et al, 1992a)
30
40
Figure 5 Costs of French Silicon-Based Grouting Technology Applied to Hanford USTs
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• average soil porosity of 0.2;
• grouting overlap of 33% with the grouted zone on either side (along the plane of the
barrier, assuming a cylindrical grouted zone) in order to ensure barrier continuity, so that
the average barrier thickness is about 1.5 times the borehole spacing;
• average drilling costs of $250/lf (although the typical costs for conventionally drilling
vertical 2.5-4 inch diameter boreholes in contaminated material at Hanford is reported to
currently be approximately $1500-2000 per linear foot, the total footage involved and the
use of streamlined techniques should bring this cost down);
• total material costs of $l/gallon for fast set grout and $2/gallon for slow set grout; and
• all other costs (eg, for shipping, mixing, injecting and verifying) are insignificant
The optimal (ie, lowest total cost) borehole spacings would thus be 12 and 8 feet for the fast and
slow grouts, respectively. However, it must be recognized that there is a maximum allowable
borehole spacing for each grout type, depending on its maximum penetration distance. For a
33% overlap between adjacent holes, the maximum spacing cannot exceed 6/5 of the maximum
penetration distance, or the designed overlap will not be achieved and "windows" in the barrier
may occur. The penetration distance, in turn, depends on the site conditions, but might
reasonably be expected to be on the order of 6 and 12 feet for the fast and slow grout,
respectively, in soils similar to those at the Hanford UST. Hence, although the optimal spacing
(ie, 12 feet) for the fast grout cannot be achieved, the maximum possible spacing (ie, 7 feet)
results in a lower total cost ($1.0 million vs. $1.2 million) than the achievable optimum spacing
for the slow grout and would be preferred. Different optimal spacings and total costs would
result for different maximum penetration distances.
Application Rate - The rate of application is determined primarily by the rate of drilling. The
grout can generally be mixed and injected in less time than it takes to drill the borehole and the
drill rig is not necessary for this procedure. Hence, the drill rig can be drilling boreholes
continuously while previously completed boreholes are grouted. This process may be accelerated
by using multiple drill rigs. The total time required to install the bowl-shaped subsurface barrier
described above, with a borehole spacing of 7 feet, would be about 93 days if the combined rate
of drilling is, for example, about 50 ft per day (ie, considering multiple shifts and multiple drill
rigs) and if other activities (eg, drill rig setup) result in about a one day delay per borehole. This
would increase to about 93 days if the borehole spacing decreased to 7 feet.
Safety of Application - There are no significant safety issues associated with the grout itself, since
it is non-toxic and US EPA National Environmental Policy Act (NEPA) approved. However, there
are the normal operating safety issues associated with drilling, mixing and injection operations,
especially at a hazardous waste site, although these operations are generally carried out at the
periphery of the site in order to contain the waste. The grout materials are nonflammable,
inorganic, alkaline or acid chemicals, which after mixing are weakly alkaline.
Acceptability of Application - The technology is relatively cost-effective, ie, potentially improving
site performance at reasonably low cost In addition, the grout material will be US supplied, can
be installed by local contractors, has been used previously in the US (for other purposes) and is
EPA NEPA approved (although for other purposes). However, it may be difficult to construct
and verify seal continuity over large areas and for long times. Hence, although such seals might
be acceptable for short-term containment (eg, prior to or during remediation), they might not be
acceptable as the sole barrier for long-term containment but only as a supplement to other
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technologies; it should be noted that it may not be acceptable in any case to leave any waste in-
place. Natural analogues and especially successful field demonstrations (eg, for the UST-ID)
would make this technology more acceptable (from an institutional, regulatory, and public
standpoint).
Comparative Evaluation of Technology Applied to Hanford USTs - The candidate technology
has been evaluated with respect to the base case in terms of their likely differences in attributes.
These assessed differences in attributes are very approximate, based on judgement, and should
subsequently be analyzed in greater detail if found to be important These assessments are
summarized below and in Table 1:
Table 1 Comparison of Candidate Technology with the Base Case Technology
ATTRIBUTES
Performance
Costs*
Schedule*
Safety*
Acceptability
1 ESTIMATED FRACTIONAL
IMPROVEMENT IN
ATTRIBUTES RELATIVE TO
BASE CASE
1+0.6
-0.2
-0.1
-0.1
+0.4
Total Score
RELATIVE WEIGHTS
Performance
0.6
0.1
0.1
0.1
0.1
+0.36
Cost
0.1
0.6
0.1
0.1
0.1
-0.04
Acceptability
0.1
0.1
0.1
0.1
0.6
+0.26
Includes additional costs associated with development and transfer, but does not include
additional savings associated with decreased likelihood of subsequent remediation.
Performance - Releases to groundwater and thereby dose to the public will be reduced
significantly (about 60%) over the long term due to the presence of a subsurface barrier,
even considering issues regarding installation and long-term integrity.
Costs - Costs will be increased slightly (about 20%) due to activities associated with in situ
grouting (including development and transfer costs), although the expected total life cycle
costs would not increase as much due to a decreased likelihood of subsequent expensive
remediation.
Schedule - The schedule will be increased slightly (about 10%) due to the additional
activities associated with in situ grouting (including development and transfer time),
although the expected total life cycle schedule would not increase as much due to a
decreased likelihood of subsequent remediation.
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• Safety - Operating hazards will be increased slightly (about 10%) due to the additional
activities associated with in situ grouting, although the expected total life cycle hazards
would not increase as much due to a decreased likelihood of subsequent hazardous
remediation activities.
• Acceptability - Acceptability will be increased moderately (about 40%) due to the
unproved long-term performance and decreased likelihood of subsequent remediation
provided by the supplementary subsurface barrier.
Tradeoffs among the various attributes can be made by assessing and applying relative weights
to the differences in attributes, and then summing the weighted differences (DuCharme et al,
1992a). The relative weights, however, will be a function of the absolute level of the attributes
of the Base Case technology, so that a specific percentage improvement in an attribute will have
greater weight if the initial value is larger. In the absence of such information for the Base Case
Technology, several sets of relative weights have been used to cover the possible range in values,
as summarized in Table 1:
• Performance Dominated - If improvement in performance is six times more important
than improvement in any of the other factors, which are otherwise equally important, the
total score for the candidate technology is +0.36, and it is thus strongly preferred.
• Cost Dominated - If improvement in cost is six times more important than improvement
in any of the other factors, which are otherwise equally important, the total score for the
candidate technology is -0.04, and it is thus slightly not preferred.
• Acceptability Dominated - If improvement in acceptability is six times more important
than improvement in any of the other factors, which are otherwise equally important, the
total score for the candidate technology is -f 0.26, and it is thus moderately preferred.
Hence, based on the assessed differences in attributes between the candidate technology and the
Base Case technology and on various sets of relative weights (where each set reflects an emphasis
on improving a different factor), it can be concluded that the candidate technology is preferred
unless cost improvement is more than about 5 times as important as improvements in other
factors.
It should be recognized that this evaluation did not include the additional savings associated
with a decreased likelihood of subsequent remediation. The sensitivity of these results to the
assessed differences in attributes (including consideration of such potential savings), as well as
to relative weights, should also be evaluated.
Proposed Issue Resolution - Issues associated with the application of the silicon-based grouting
technology relate primarily to waste compatibility, long-term integrity, grout penetration (distance
and uniformity), and barrier verifiability. In addition, for horizontal barriers, issues relate to the
ability to drill stable horizontal grout holes.
Laboratory and field tests for barrier construction are necessary to resolve these issues and
complete development of this technology for this application, and are being proposed for the
UST ID. This would include three phases: (1) laboratory bench scale testing to determine waste
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compatibility, long-term integrity and post soil injection performance; (2) single borehole injection
tests to determine penetration characteristics under field conditions; and, if warranted, (3)
multiple borehole injection tests to determine barrier characteristics. The laboratory tests would
include enhanced 9CV90 testing, as recommended by EPA guidelines, supplemented with radiation
and high heat Accelerated testing would use simulated wastes for the Hanford UST, which is
a Battelle-PNL recipe and is itself hazardous. All the testing phases would include consideration
of verification, ie, testing of the electrical resistivity and dielectric properties of the grout in the
laboratory and calibration of the geophysical testing in the multi-hole field test (eg, by subsequent
drilling and sampling, or even excavation and inspection, of the barrier). The field tests would
be conducted, for safety and economics, at a similar but uncontaminated site. Additional work
may be necessary to customize the material for specific soiVwaste conditions and for refining the
horizontal drilling and verification techniques. Natural analogues (if any) for the grout will be
investigated.
The time to complete development of this technology (ie, demonstration at Hanford UST) is
estimated to be on the order of less than two years. This does not include development of
horizontal drilling techniques or new geophysical verification techniques.
Recommendation - The detailed evaluation suggests that the silicon-based grout represents an
improved technology for application to the Hanford USTs, and thus warrants further
consideration.
CONCLUSIONS
DOE must make a variety of decisions within their EM program regarding (1) development and
transfer of improved EM technologies and (2) application of the optimum EM technologies at
specific sites. To assist in this decision-making process, a methodology has been developed for
evaluating EM technologies in terms of (1) the degree to which they would accomplish specific
EM activities and satisfy specific requirements, under various conditions, if they were available,
and (2) the costs and risks (if any) associated with their becoming available. For demonstration
purposes, this methodology was applied at different levels of detail to two grouting technologies:
• The generic application of a Ukrainian clay-based grouting technology was evaluated in
a preliminary fashion. It was determined that this technology, if available, represents a
potential improvement over other grouts in "open" geologic systems. Hence, development
and transfer to the US should be completed if containment in such conditions is a large
enough problem for DOE to justify the development/transfer costs.
• The specific application of a French silicon-based grouting technology to the Hanford
USTs was evaluated in a detailed fashion. It was determined that this technology, if
available, represents a potential improvement over the current base case technology for
the Hanford USTs, even when the costs of making the technology available are
considered. Hence, development and transfer to the US should be completed, and if
successful its application to the Hanford USTs should be strongly considered.
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REFERENCES
Boomer et al, 1990, "Functional Requirements Baseline for the Closure of Single-Shell Tanks,"
WHC-EP-0338, draft report by Westinghouse Hanford Company to US Department of Energy -
Office of Environmental Restoration and Waste Management, June.
DuCharme, A., W. Roberds, and R. Jimenez, 1992a, "Matching Leading DOE Waste Management
and Environmental Restoration Needs with Foreign-Based Technologies", report prepared for US
Department of Energy - Office of Environmental Restoration and Waste Management,
International Technology Exchange Program, October.
DuCharme, A., R. Jimenez, and W. Roberds, 1992b, "International Technology Transfer to Support
the Environmental Restoration Needs of the DOE Complex", Proceedings of the Nuclear and
Hazardous Waste Management International Topical Meeting - Spectrum 92, Boise ID, August
Harrington, M., and C. Harlan, 1992, "EnviroTRADE: An Information System for Providing Data
on Environmental Technologies and Needs Worldwide", Proceedings of the Nuclear and
Hazardous Waste Management International Topical Meeting - Spectrum 92, Boise ID, August
Rouse et al, 1992, "Underground Storage Tank - Integrated Demonstration Functional
requirements", WHC-EP-0566, draft report by Westinghouse Hanford Company to US
Department of Energy - Office of Environmental Restoration and Waste Management, April
Spickelmier, K., 1992, "Former USSR's Largest Grouting Firm Speaks to US Audience", Mining
Engineering. August
Verma, T., 1992, 'Potential Application of the Ukrainian Grouting Technology in the
Environmental Restoration Area", US EPA Fourth Forum on Innovative Hazardous Waste
Treatment technologies: Domestic and International, San Francisco, California, November.
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DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY (SITE)
Dr. Ernest Mayer
E. I. du Pont de Nemours, Inc.
Du Pont Engineering, Louviers 1359
P. O. Box 6090
Newark, DE 19714
(302) 366-3652
Abstract
The novel Du Pont/Oberlin Microfiltration Technology has recently been
demonstrated in EPA's Superfund Innovative Technology Evaluation (SITE)
program. Its key features are fine microfiltration at low cost using Du Font's new
Tyvek®* T-980 flashspun olefin filter media coupled with Oberlin's reliable
automatic pressure filter (APF) and Enviroguard's PROFIX" filter aid for metals
stabilization.
This new microfiltration technology is best suited for contaminated heavy metal
wastewaters and groundwaters. The SITE demonstration (1990) actually removed
Zn, Cu, Cd, Se and Pb from the Palmerton, 'PA Zinc smelting Superfund site.
Basically, 99.95% removal of Zinc and Total Suspended Solids (TSS); and firm,
dry (41% solids) cakes that passed both the "Paint Filter Test" and TCLP were
demonstrated. Thus, this new technology provides low cost metals
removal/stabilization all in one simple operation.
This paper will describe this new technology in detail, and will present some typical
application results. It will also detail where it has been applied since the SITE
demonstration.
* Du Font's trademark for its flashspun HOPE nonwoven filtration media.
" Enviroguard's trademark for its patented filter aid/stabilization agent.
296
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DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY (SITE)
Dr. Ernest Mayer
E. I. du Pont de Nemours, Inc.
Du Pont Engineering Louviers 1359
P. O. Box 6090
Newark, DE 19714
(302) 366-3652
TYVEK'T-980 MEDIA
Du Pont has commercialized a new filter media based on flash spinning technology for
Tyvek spunbonded olefin. It has an asymmetric pore structure, a greater number of submicron
pores, and a smaller average pore sizel. As a consequence, it has superior filtration properties
and longer life, and in many instances it can compete with microporous membranes, PTFE
laminates, and various melt-blown medial. Its key property is its tight pore structure at a very
low cost compared to competitive products. Table I outlines the media cost per gallon of waste
filtered and shows that the T-980 grade, which is the lowest basis weight manufactured
(0.9 oz/yd2) and the only grade evaluated here, is very cost effective. In most applications the
T-980 grade was sufficient so the added cost for a higher basis weight grade was not
warranted. For example, T-980 produced slightly poorer effluent quality than the 'standard'
0.45(1 microporous membrane at a fraction of the cost; equivalent effluent quality to the PTFE
laminate at a fraction of the cost; and much better effluent quality than typical 1- and 5- micron
melt-blowns at equal or significantly lower cost (depending on application 2). Tests with actual
wastes showed the greatest cost benefit (Table I). A similar cost benefit was obtained in
operation with a low-level radioactive plating waste at the Savannah River Plant2-3. This
installation realized almost a $350M annual savings when T-980 media was used with a more
efficient filter aid. An added benefit is its superior strength compared to microporous
membranes and the PTFE laminate media. This strength permits its use in robust automatic
pressure filters 4. The high strength 5 coupled with the tight, ~1- micron pore structure 1 led
to its use in the EPA Superfund SITE program 6~9.
OBERLIN AUTOMATIC PRESSURE FILTER (APF) **
T-980 media requires a suitable filter housing. The Oberlin Filter Company's automatic
pressure filter (APF) was chosen for its simplicity and fully automatic operation 10. Their APF
has other advantages, namely:
• Completely automatic, unattended operation save for disposable media roll
replacement and chemical treatment makeup. Standard PLC control.
• Enclosed operation for safety and handling of hazardous wastes.
• Fairly high operating pressure (up to 60 psig).
297
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• Complete in-line treatment-chemical addition, ie, filter aids and polymer flocculants.
• Automated shutdown flushing capability.
• Cake washing capability to remove hazardous filtrate, if required.
• Automatic, positive dry cake discharge.
• Direct submicron filtration without the need for further downstream processing.
• Reliable, low-maintenance performance.
• Completely automatic safety interlocks and enclosures and/or purging, if required.
• Explosion-proof design, if required.
• Completely integrated pumping system(s), if required.
• Dirty-media takeup and doctoring, brushing, or washing, if required (automatically
accomplished during takeup); and, optional media reuse if desired.
DU PONT TYVEK®/OBERLIN MICROFELTRATION TECHNOLOGY
Thus, the Du Pont Tyvek/Oberlin Microfiltration technology has some unique
advantages, especially its completely automatic submicron, low-cost filtration and its dry cake
discharge 6. This dry cake discharge feature is precisely why the resultant cakes pass the
modified EPA "Paint Filter Test" for land disposal n and in some instances pass the new EPA
TCLP (Toxic Characteristic Leaching Procedure) test for hazardous components 12"15,
provided a stabilization agent is used (i.e., Profix*** was used in the SITE program 9). Dry
cake/submicron filtration in one operation is why the Microfiltration technology was selected at
Savannah River over conventional crossflow microfilters and ultrafilters. In plating-waste
treatment the simple, one-step Microfiltration technology replaced the conventional three-step
clarifier/overflow sand filter/underflow recessed filter press process. However, the purpose of
this paper is to highlight case histories where the Microfiltration technology has been
successfully applied. The technology is most suitable for hazardous wastewater where the
solids loading is not too high (i.e., generally less than about 5000 ppm). Examples include
contaminated grpundwater, plating wastewaters, low-level radioactive wastes, plant equip-
ment/floor washings, cyanidic wastes, plant wastewaters that contain heavy metals, and metal
grinding wastes 2,3 & 6_ jn most of these cases Profix was used per the SITE technology 9 to
accomplish automatic, submicron, low-cost microfiltration and stabilization all in one simple
operation.
Enviroguaid's trademark for its patented filter aid/stabilization agent.
298
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CASE HISTORIES
•Many successful case histories have been presented previously 2, but a few are worth
repeating here, especially those involving heavy metals removal and stabilization. Other new
applications are also presented.
Savannah River Operation
Table n details actual Savannah River plant wastewater treatment specifically aimed at
aluminum and uranium removal3. The data were obtained from two T-980/Oberlin units
which had been operating for about four years. Aluminum forming and metal finishing
operations generate a high content of solids, aluminum, and turbidity. These solids can be
reduced below the National Pollution Discharge Elimination System (NPDES) limits with the
Microfiltration technology at very high 1200 gfd (gallons/sq ft/day) rates16. This rate is about
six times higher than the ultrafilter (UF)/reverse osmosis (RO) system (200 gfd) originally
considered. Pilot testing also showed that the UF/RO system repeatedly fouled with this
waste, requiring aggressive cleaning agents which significantly added to the waste volume.
Plans are now underway to evaluate Profix in this operation.
Electronics Manufacturing Plant Wastewater
This plant's effluent exceeded the local sewer authority's lead discharge limit. As a
consequence, the plant was mandated to cease discharge and dispose of their wastewater in an
off-site hazardous waste landfill at a $0.55/gallon cost. Two Microfiltration systems were
installed instead of crossflow microfilters because their dry cake feature significantly reduced
waste volume^ These units repaid their cost in three months of operation based on disposal
cost savings alone 16.
Table HI details actual plant operation and compares the Microfiltration effluent with the
plant's discharge limits. As shown, these units reduced the effluent Total Suspended Solids
(TSS) and lead levels to well below the plant's required discharge limits at high 800 gfd flux
rates. In addition, these units routinely achieved >50% solids dry cakes that could be disposed
of in a RCRA-approved landfill (at significant cost savings compared to the concentrate from
the crossflow microfilters). Subsequent evaluation of the-Profix filter aid/stabilization agent
per the SITE technology 9 actually improved flux and resulted in stabilized cakes (passed
TCLP).
Electronics Plant Cartridge Replacement
This plant's effluent had to be polished by absolute 0.45-micron cartridge filters to meet
heavy-metal discharge limits. Cartridge costs exceeded $1200 daily plus significant labor
charges 16. A Microfiltration system was installed at significant cost savings compared to
these cartridges or a crossflow microfilter which was also considered. Payback was on the
order of three months; the system produced dry cakes suitable for landfilling off-site, and
significant labor savings resulted.
Table IV demonstrates that the Microfiltration system easily met the TSS and lead
discharge limits at very high 1500 gfd flux. Cakes were also quite dry at ~50% solids.
299
-------
Clarifier Underflow Heavy Metals Removal
This plant was faced with a land ban of their main claiifier metal hydroxide underflow
sludge (2-3% solids) because it did not pass the EPA "Paint Filter Test" n. This clarifier
treated the entire plant effluent and removed primarily lead, zinc, and copper. To satisfy the
RCRA land ban restrictions, the plant hired an expensive ($400/day) mobile dewaterer who
used a manual, recessed-chamber filter press that produced sloppy cakes. These cakes had to
be shovelled into dumpsters for off-site disposal. The Microfiltration technology was installed
about three years ago. Table V shows excellent effluent quality at very high, 10,000 gpd
capacity and 900 gfd flux. The cakes were sufficiently dry (50% solids vs. 40% requirement)
to pass the "Paint Filter Test" and were acceptable to the hauler/landfill operator at a significant
cost saving to the plant The Microfiltration system operates automatically at significant labor
savings compared to the manual press. Profix has been evaluated here and was implemented
recently since the resultant cakes pass TCLP particularly for lead (Table V). As a result, off-
site disposal costs were reduced about $200M annually.
Battery Manufacturing Heavy Metals Removal
This plant consistently exceeded their permitted discharge limits from their conventional
clarifier/underflow press system and considered an overflow polishing sand filter.
Simultaneously, they heard of our Microfiltration technology and decided to evaluate it as a
polishing filter. Testing showed that it could replace the entire clarifier/press installation.
Table VI shows excellent metals removal, TSS reduction, and excellent effluent turbidity
(0.5 MTU). Flux is quite high at 2400 gfd and capacity from the single system exceeds
60,000 gpd. These benefits are in addition to dry cakes that could be easily disposed of in a
RCRA-approved landfill.
Heavy Metals Removal from Chemical Plant Wastewater
This plant was faced with severe heavy metal discharge restrictions based on recent EPA
chronic toxicity regulations (ie, 15 ppb Cu, 60 ppb Pb, 130 ppb Ni, 150 ppb Or, and 300 ppb
Zn). In addition, this mixed heavy metals waste had to be stabilized to meet the "third-third"
EPA BDAT (Best Demonstrated Available Technology) regulations for land disposal
2,12 & 13> jon exchange was first evaluated, but it could not meet the low ppb limits for all
the metals and its regenerant required off-site stabilization at high cost As a result, the
Microfiltration technology was next evaluated since it could produce dry, stabilized cakes, but
previously it never achieved these low metals limits. An extensive pilot testing program was
conducted and finally, it was demonstrated that these limits could be achieved quite routinely
(Table VII). In addition, these low metals limits were obtained at a very high 3600 gfd flux;
and the resultant "dry" cakes passed the TCLP test for all eight toxic metals (per EPA "third-
third" regulations issued May 8,1990 12 & 13). As a consequence, the Microfiltration
technology was selected and one large system (along with a Profix addition system) has been
operating successfully for one year; and a second system is being installed now.
Groundwater Lead Removal
A RCRA hazardous site required lead removal from contaminated groundwater to a level
of less than 50 ppb to meet primary drinking water standards as well as the chronic toxicity
criteria. The responsible party hired an outside consulting firm to study and recommend a
suitable treatment scheme. Unfortunately, their piloted treatment process could only achieve
300
-------
4 ppm; and their recommended activated carbon polishing step also could not achieve the low
required 50 ppb lead discharge limit. The Microfiltration technology was then evaluated and
outstanding <10 ppb lead removals were obtained (Table Vin). As a result, this technology
will be used and a single large system is being installed. Profix was used here and the cakes
passed TGLP for lead.
Chemical Plant's Groundwater Metals Removal
This plant had .groundwater contaminated with metals and organics, and hired an outside
consulting firm to study and recommend a suitable treatment scheme. Unfortunately, their
piloted sarid filter scheme couldn't achieve the required low metals levels; and as a result the
Microfiltration technology was evaluated. As can be seen from Table IX, it achieved
outstanding metals removal (i.e., below detection limits) at a very high 4000 gfd flux. In
addition, filtrate turbidity, TSS, and cake % solids were all excellent; and the cakes passed
TCLP. As a result, the system is now being installed to treat this groundwater.
Groundwater Hexavalent Chrome Removal
This Superfund site required groundwater chrome removal to the 50 ppb level. Simple
sodium bisulfite chrome reduction followed by Microfiltration resulted in excellent chrome
removal to below the 50 ppb detection limit, as well as excellent filtrate TSS and turbidity
(Table X). Flux was very high at 3600 gfd and the resultant cakes were stabilized. However,
the client opted for ion exchange (DC) since only one metal was present and it reduced solid
waste volume. In this case, IX was a better choice for the client; and illustrates that all metals
removal technologies have their niche.
Groundwater Mixed Metals Removal
This mixed organics/metals contaminated groundwater was chemically treated to destroy
the toxic organics and the resultant effluent was treated by the Microfiltration technology
(Table XI). As can be seen from Table XI, excellent metals removals were obtained basically
to the detection limits. Flux was reasonable (1750 gfd) considering the high 50 ppm Fe
content; cakes passed the new TCLP test; and filtrate turbidity and TSS were outstanding at
0.05 NTU and 0.03 ppm, respectively (i.e., better than distilled water). In this case, the
regulatory limits were later relaxed so direct discharge was possible; and the Microfiltration
technology was not required.
Wastewater Mixed Metals Removal
This plant required stringent heavy metals removal to meet chronic aquatic toxicity
criteria. A variety of technologies were evaluated, but the Microfiltration technology provided
the best overall metals removal of this waste (Table XII) as most were removed to below
detection limits. The resultant cakes also passed TCLP, which,was also a big factor since other
technologies required additional post-treatment to produce stabilized solids.
Wastewater Zinc Removal
This wastewater required zinc removal to 1 ppm prior to discharge; and in this case, only
the Microfiltration technology was evaluated because selective ion exchange could not achieve
the 1 ppm limit. Table Xin shows that the Microfiltration system easily achieved the 1 ppm Zn
301
-------
limit as well as excellent Cd, Pb, and Cu removals like in the SITE demonstration 9 where
these metals are normally associated with Zn smelting. In addition, filtrate turbidity and TSS
were excellent and flux was reasonably high (1000 gfd) for this high 3000 ppm TSS waste.
Cakes again passed the TCLP test In this case, despite the promising microfiltration results
the plant opted to incinerate this waste.
Explosives Plant Pb Removal
This plant sends their Pb wastewater off-site for treatment and stabilization at considerable
expense. They heard of the Du Pont/Oberlin Microfiltration technology and evaluations in
Table XIV demonstrated complete feasibility as Pb was removed to well below the proposed
discharge limits and cakes passed TCLP at a reasonably high 2000 gfd flux. As a
consequence, a small system has been started up recently.
Chelated Wastewater Cu Removal
This plant had two wastewater streams which required Cu removal to meet the 50 ppb toxic
discharge limit as well as to protect the on-site biological waste treatment system. One stream
contained chelated Cu (Case II) while the other was chelated as well as heavily contaminated
with organics (Case II). Ion exchange and oxidation with iron were tried on Case I stream
with litSe success while hot sodium sulfide precipitation was successfully demonstrated for
Case H after the organics were removed. However, it was later found that complete organics
removal could not be assured so the Microfiltration technology was evaluated on both streams.
Table XV shows that Cu removal to 10 ppb was obtained at high 4200 gfd flux (Case I) and
<200 ppb Cu at 300 gfd flux for Case H The higher -200 ppb Cu in Case II was due to the
copious ~50% organics present, but combined waste discharge was below 50 ppb. In
addition, both cakes passed TCLP and even organics were stabilized when a mixed
Profix/organic stabilizer (FO1) was used. Economics showed that Case I treatment costs
amounted to low $1.60/1000 gallons while Case II about $130/1000 gallons, but Case H
disposal cost savings amounted to about $1350/1000 gallons due to the high level of organics
present that could be recovered and recycled. As a consequence, a project is being
implemented to install a Microfiltration system.
ACTUAL EPA SITE DEMONSTRATION
The Du Pont/Oberlin microfiltration technology was demonstrated by the EPA under the
SITE program in April - May, 1990 at the Palmerton, PA Superfund site 7-8-9-& 16. This
site's groundwater is contaminated with heavy metals by runoff from a huge 2.5 mile long
cinder bank as a result of a zinc smelting operation. As expected, the groundwater contained
high concentrations of zinc as well as manganese, lead, cadmium, copper and selenium (Table
XVI). The Microfiltration system was able to remove 99.95% of the zinc, 99.95% of the TSS,
produce dry cakes that passed the "Paint Filter Liquids Test", 41% cake solids, filtrate that met'
NPDES discharge limits, and cakes that passed both the EP Toxicity and the new TCLP test,
because the new filter aid / stabilization agent (Profix) was used 7«8-9-& *6.
SUMMARY
These cases and actual operating applications demonstrate the utility of the Du Pont/
Oberlin microfiltration technology to remove heavy metals at very high flux rates and to
simultaneously produce dry cakes that pass the EPA "Paint Filter Test", and in some cases, the
302
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new EPA TCLP leaching test (if Prefix filter aid/stabilization agent is used per SITE
demonstration - Refs. 2,6,7,9). This technology is quite competitive when compared to
microfilter cartridges, crossflow microfilters, and ultrafilters. In some instances, the system
can replace the conventional three-stage metal finishing treatment process of clarifier,
underflow filter press, and overflow polishing sand filter. Thus, the waste engineer/consultant
now has a simpler, one-step process for treating and stabilizing hazardous metal-bearing
wastewaters and groundwaters.
REFERENCES
1 H S. Lim and E. Mayer, 'Tyvek® for Microfiltration Media," Fluid/Particle Separation
Journal. 2(1): 17, (March, 1989).
2. E. Mayer, "Du Pont/Oberlin Microfiltration System for Hazardous Wastewaters," Paper
presented at US EPA Second Forum on Innovative Hazardous Waste Treatment
Technologies", Philadelphia, PA, May 15-17,1990.
3. H. L. Martin, "Wastewater Filtration Enhancement," Paper presented at 10th Annual
AESF/EPA Conference on Environmental Control for the Metal Finishing Industry,
Orlando, FL, January 23-25, 1989.
4. E. Mayer, "New Trends in SLS Dewatering Equipment," Filtration News. 24
(May/June, 1988).
5 Du Pont Tyvek® Bulletin E-24534, "Tyvek® Engineered Specifically for Filtration,"
(1988).
6. E. Mayer, Request for Proposal, SITE-3 Solicitation, Demonstration of Alternative
and/or Innovative Technologies, "Groundwater Remediation Via Low-Cost
Microfiltration for Removal of Heavy Metals and Suspended Solids," (February, 1988).
7. K. Topudurti, S. Labunski, and J. Martin, "Field Evaluation of a Microfiltration
Technology to Treat Groundwater Contaminated with Metals" Proceedings of 11th
National Conference, Superfund '90, Washington, DC, November 26-28,1990,
pp 425-432.
8. G. L. Stacy and S. C. James, "The Superfund Innovative Technology Evaluation (Silt)
Program," Control Hazardous Materials. 4(1): 23 (January/February, 1991).
9. EPA Final Technology Evaluation Report: "SITE Program Demonstration of the
Du Pont/Oberlin Microfiltration Technology," (July 1991).
10. Oberlin Filter Co.'s Bulletin, "Oberlin Pressure Filter," (February, 1988).
11. N. J. Sell, "Solidifiers for Hazardous Waste Disposal," Pollution Eng.. 20(8): 44 (August,
1988).
303
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12. Federal Register, Vol. 51, No. 114 (June 13, 1986); and updates: Vol. 53, No. 159
(August 17,1988) and Vol. 55, No. 61 (March 29,1990).
13. J. Newton, "Understanding the Toxicity Characteristic Rule," Pollution Eng.. 22(9)- 90
(September, 1990). B w
14. J. Biedry, "Managing Waste to Meet Federal Land Ban Rules," Pollution Eng.. 22(10)-
46 (October, 1990). '*" U }'
15. J. Hauck and S. Masoomian, "Alternate Technologies for Wastewater Treatment,"
Pollution Eng.. 22(5): 81 (May, 1990).
16. EPA Final Applications Analysis Report: "Du Poni/Oberlin Microfiltration Technology "
(May, 1991).
304
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TABLE I
MEDIA
COST PER GALLON WASTE FILTERED
Actual Costs/Gallon Filtrate (cents/gal)*
Media
Microporous Membrane
Tyvek® T-980
PTFE Laminate
Melt-blown PP
Melt-blown PP
Nom.
Rating
(urn)
0.45
1
0.8
1
~5
Overall
Filtrate
Quality
Excellent
V. Good
V. Good
Good
Poor
600 ppm
ACFTD"
29
1.3
41
2.4
1.5
Low-Level
Radioactive
Waste
69
1.7
63
6.5
4.0
Lead-
Bearing
Waste
14
0.3
12
1.3
0.8
Based on actual media costs, flux rates, and measured life cycles.
AC Fine Test Dust (ACFTD) challenge tests.
TABLE H
ACTUAL SAVANNAH RIVER PLANT OPERATION
WITH DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
. Aluminum (ppm)
Lead (ppm)
Zinc (ppm)
Copper (ppm)
Uranium (ppm)
Capacity (gpd)
Flux (gfd)
Actual State
Raw
Waste
110
687
127
1.6
0.5
2.0
2.3
35,000
•
discharge permit values.
T-980/
Oberlin
0.32
1.4
0.95
0.2
<0.1
<0.1
0.01
60,000
1,200
NPDES
Limits*
~
31
3.2
0.43
0.32
0.21
0.5
—
—
305
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TABLE Hi
ACTUAL ELECTRONICS MANUFACTURING PLANT WASTEWATER
WITH DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Lead (ppm)
Barium (ppm)
Cadmium (ppm)
Capacity (gpd)
Flux (gfd)
Cake % Solids
Cakes Pass TCLP?
Raw
Waste*
>1,000
1,000
20
25
2
2,500
—
—
No
Du Pont/
Oberlin
0.3
<1
0.04
-------
TABLE V
CLARIFIER UNDERFLOW HEAVY METALS REMOVAL
WITH DU PONT/OBERLIN MICROFILTRAT1ON TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Lead (ppm)
Zinc (ppm)
Copper (ppm)
Capacity (gpd)
Flux (gfd)
Cake % Solids
Cakes Pass TCLP?
Raw
Waste*
>1,000
17,000
40
410
1,050
6,800
—
—
No
Du Pont/
Oberlin
1.0
2.5
<0.01"
0.2
1.2
10,000
900
50
Yes
Discharge
Limits
NR
20
5.0
5.0
5.0
—
—
40
Must pass
TABLE VI
DIRECT FILTRATION FOR HEAVY METALS REMOVAL
FROM A BATTERY MANUFACTURING PLANT
WITH DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY ***
Property
Turbidity (NTU)
TSS (ppm)
Nickel (ppm)
Cadmium (ppm)
Zinc (ppm)
Cobalt (ppm)
Capacity (gpd)
Flux (gfd)
Raw
Waste
175
1,600
30-50
15-40
0.2-1.0
0.4-1.5
40,000
—
Du Pont/
Oberlin
0.5
<1
<0.10
<0.05
<0.10
<0.05
60,000
2,400
Discharge
Limits
NR
20
2.27
0.4
1.68
0.22
— .
—
* Existing plant clarifier underflow sludge was prevbusly hauled off-site to hazardous landfill.
*• Detection limit
•** Replaced clarifier and underflow press.
NR <= Not Regulated.
307
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TABLE VII
HEAVY METALS REMOVAL FROM CHEMICAL PLANT WASTEWATER
WITH DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Copper (ppb)
Lead (ppb)
Zinc (ppb)
Nickel (ppb)
Chromium (ppb)
Capacity (gpd)
Flux (gfd)
Cakes Pass TCLP?
Raw
Waste
>100
100
2,000
100
3,500
400
1,000
75,000
—
No
Du Pont
Oberiin
0.06
<0.2
<5
<5*
<10*
<5*
<100*
130,000
3,600
Yes
Discharge
Limits"
<0.2
<1
15
60
250
130
150
...
._
Must Pass
TABLE VHI
GROUNDWATER LEAD REMOVAL
WITH DU PONT/OBERUN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Lead (ppb)
Flux (gfd)
Cakes Pass TCLP?
* Detection limits
Based on EPA
NR m Not Regulated
Raw
Groundwater
<10
120
20,000
—
No
Chronic Toxicity tests
Du Pont/
Oberiin
0.1
<0.2
£10
1,400
Yes
Discharge
Limits "
NR
30
50
«.»
Must Pass
308
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TABLE IX
CHEMICAL PLANT GROUNDWATER METALS REMOVAL WITH
DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Fe (ppm)
Ba (ppb)
Cr (ppb)
Ni (ppb)
Zn (ppb)
Cake % Solids
Flux (gfd)
Cakes Pass TCLP?
Raw
Groundwater
100
80
40
900
45
50
300
—
—
No
TABLE
Du Pont/
Oberlin
0.17
0.3
-------
TABLE XI
GROUNDWATER METALS REMOVAL WITH
DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Fe (ppb)
Cr (ppb)
Ni (ppb)
Zn (ppb)
Flux (gfd)
Cakes Pass TCLP?
Raw
Groundwater
160
180
50,000
40
300
14,000
—
. No
TABLE
Du Pont/
Oberlin
0.05
0.03
<100*
10
<5*
<10*
1750
Yes
XII
Discharge
Limits ••
NR
30
NR
150
130
300
...
Must Pass
MIXED WASTEWATER METALS REMOVAL WITH
DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Fe (ppm)
Cr (ppb)
Cu (ppb)
Zn (ppb)
Cake % Solids
Flux (gfd)
Cakes Pass TCLP?
* Detection limit
Based on EPA
NR = Not Regulated
Raw
Groundwater
<1000
1200
80
1800
1000
14,000
—
—
No
*
Chronic Toxicity Tests.
Du Pont/
Oberlin
0.2
0.4
-------
TABLE XMI
WASTEWATER ZINC REMOVAL WITH
DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY
Property
Turbidity (NTU)
TSS (ppm)
Zinc (ppm)
Cd (ppm)
Pb (ppm)
Cu (ppm)
Flux (gfd)
Cake Pass TCLP?
Raw
Wastewater
>1000
3000
1500
0.15
0.70
0.25
—
No
TABLE
Du Pont/
Oberlin
0.06
0.13
<0.01*
-------
TABLE XV
WASTEWATER Cu REMOVAL WITH DU PONT/OBERLIN
MICROFILTRATION TECHNOLOGY
Property
1. Chelated Case:
Turbidity (NTU)
TSS (ppm)
Fe (ppb)
Cu (ppb)
Flux (gfd)
Cakes pass TCLP?
2. Organics Case:
Turbidity (NTU)
TSS (ppm)
Cu (ppm)
Flux (gfd)
Cakes pass TCLP?
- with PROFIX
-withPROFIXFOl
Organics Recovery
(Vol %)
Raw
Wastewater
20
25
500
2,500
No
>1000
30,000
1600
NO
~10%
Du Pont/
Oberiin
<0.3
<0.2
20
10
4200
Yes
2
<0.2
300
Yes
(Metals Only)
(Metals & Organics)
98.6%
Discharge
Limits
50
Must Pass
0.2
Must Pass
Cannot Discharge
TABLE XVI
DU PONT/OBERLIN MICROFILTRATION TECHNOLOGY DEMONSTRATION
BY EPA AT PALMERTON, PA SUPERFUND SITE
Property
Turbidity (NTU)
TSS (ppm)
Zinc (ppm)
Manganese (ppm)
Lead (ppm)
Cadmium (ppm)
Copper (ppm)
Selenium (ppm)
Cake % Solids
Cakes Pass EP Tox?
Cakes Pass TCLP?
* Detection Limit.
NPDES discharge
NRs Not Regulated.
Raw
Waste
>1,000
1,700
500
50
0.1
0.5
0.2
0.1
—
No
No
limits.
Du Pont/
Oberiin
0.1
0.8
0.25
40
Yes
Yes
Discharge
Limits"
NR
30
2.4
NR
0.7
0.2
NR
NR
NR
NR
Must Pass
312
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U.S. ARMY CORPS OF ENGINEERS
TOXIC AND HAZARDOUS MATERIALS AGENCY
Composting of Explosives-Contaminated Soil
at the U.S. Army UmatiSIa Depot Activity
Composting
Composting is a controlled biological process by which
biodegradable materials are converted by microorganisms to
innocuous, stabilized by-products. Inmost cases, this is achieved
by the use of indigenous microorganisms. Explosives -contaminated
soils are excavated and mixed with bulking agents such as wood
chips, and organic amendments such as animal, fruit and vegetative
wastes. Maximum degradation efficiency is controlled by
maintaining moisture content, pH, oxygenation, temperature and the
carbon to nitrogen ratio. There are three process designs used in
composting; aerated static piles, windrowing, and mechanically
agitated in- vessel composting (Figure 1) . This technology requires
substantial space to conduct the composting operation and results
in approximately a two fold volumetric increase in material due to
the addition of amendment material.
The first composting demonstration for explosives -contaminated
soils conducted at Louisiana Army Ammunition Plant (L&AP)
demonstrated that aerobic, thermophilic composting is able to
reduce the concentration of explosives (TNT, RDX and HMX) and
associated toxicity to acceptable health based clean-up levels.
However, an economic analysis determined that full scale
implementation of composting of explosives -contaminated soils using
previously investigated design parameters was not economically
competitive with incineration. An optimization field demonstration
was initiated at a National Priority List (NPL) site at Umatilla
Depot Activity, Hermiston, OR, to investigate several process
design parameters that would make this technology more cost
effective. In addition, extensive chemical characterization and
toxicity studies were conducted on the final composted product.
313
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General Site Information
Umatilla Depot Activity (UMDA) , Henniston, OR, was selected as
the site for the compost optimization field study. Between 1950
and 1965, a washout facility for recovering explosives from
unserviceable munitions was operated at UMDA. Pressurized hot
water was used to melt out explosives from munition bodies and
upon cooling and settling, the explosives were recovered Large
quantities of water were contaminated with explosives "in this
operation. It was standard practice, at the time, to discharge this
water into unlined settling basins. Explosives contained in these
waters consisted of TNT, RDX and HMX. in 1987, these washout
lagoons were placed on Environmental Protection Agency's EPA
National Priorities List (NPL) because of the presence of
explosives in the water table aquifer some 50 feet beneath the
lagoons. ^The explosives concentration levels in the washout
lagoons soils approach a maximum concentration of 10% (100 000
mg/kg} . Explosives contaminated soils from these lagoons were hand
excavated for this composting optimization study. The mean
concentrations of TNT, RDX and HMX were 13,380, 1,071, and 274
, respectively.
Optimization Field Study OtHeetivea and Deaicm
The primary objective of this composting optimization field
study was to increase the quantity of soil processed in a
composting treatment system per unit time. Since soil throughput
is dependent on the rates of degradation and the percent soil
loading, the key variables investigated in this study were
amendment mixture composition and percent contaminated soil
loading. In addition, two technologies were evaluated, aerated
static pile and mechanically agitated in-vessel composting systems.
Amendment selection was based on adiabatic testing using a
combination of fifteen readily available agricultural wastes. The
amendments selected and their approximate cost are provided in
Table 1. Percent soil loading was investigated using seven 3 cubic
yard aerated static pile systems which were constructed from
fiberglass to model actual static pile conditions (Figure 2) The
tests were used to investigate soil /amendment ratios using 6 7
10, 20, 30 and 40 volume percent of explosives -contaminated soil
and composted for 90 days. Different soil amendment ratios and
amendment mixture compositions were investigated using a special
seven- cubic yard pilot scale mechanically agitated in-vessel (MAIV)
system which was constructed according to rigorous explosive saf etv
standards by Fairfield Engineering Co., Marion, Ohio (Figure 2)
314
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The mechanical pilot system uses rotating augers attached to the
rotating cover to mix the compost. The first two tests
investigated two different amendment compositions using 10%
contaminated soil volume. The final two tests were used to
investigate soil/amendment ratios using 25 and 40 percent volume of
explosives contaminated soil with the optimum amendment composition
selected from the previous tests. The MA.IV tests were composted
for 44 days.
The static pile systems and the MAIV system were housed in
greenhouses to protect them from the environment and prevent the
spreading of contamination from explosives contaminated dust. A
computer-based data acquisition and control system was used to
monitor and regulate the environment in each of the compost
systems. Temperatures were kept from exceeding 55°C using forced
aeration and the moisture content maintained between 45 - 50
percent. Compost samples were taken at various time intervals,
homogenized and split into two fractions. Chemical analysis for
the presence of TNT, RDX and HMX were conducted by High Performance
Liquid Chromatagraphy methods on the first fraction while the
second fraction was subjected to toxicity testing.
Since the implementation of this technology will be based on
it's ability to meet health based clean-up criteria, the second
objective was to conduct a chemical characterization and
toxicological evaluation of the resultant composted material.
Leachates from the EPA Synthetic Precipitation Leachate Test
(referred to as the "Clean Closure Leaching Test or CCLT) and
organic solvent leachates were subjected to Ames bacterial
mutagenicity tests, acute and chronic toxicity tests using the
aouatic crustaceans Ceriodaphnia dubia. and a rat oral toxicity
screening of finished compost. Characterization included
determination of the explosives and TNT metabolites in the composts
and organic solvent extracts.
Optimization Study Results
The composting optimization study confirmed the LAAP composting
study results which indicated that composting can effectively treat
TNT RDX and HMX contaminated matrices. The optimization study
indicated that both static pile and MAIV composting technological
approaches for implementing composting are effective in degrading
explosives. The percent reduction of explosives observed in the
tests are provided in. Table 2. In the static pile tests, the
majority of the degradation occurred in the first 44 days of
composting while in the MAIV tests the majority of the degradation
occurred in the first 10 days. The results of this optimization
315
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study indicated the amendment composition is an important parameter
in achieving maximum reduction of RDX and HMX. The maximum loading
level for both technologies appears to be 30 volume percent and
mixing is important in achieving rapid and extensive destruction of
explosives. Since mixing is an important process design parameter
a composting windrow field demonstration has been initiated. '
Chemical characterization and toxicity testing on the finished
compost sponsored by the U.S. Army Biomedical Research and
Development Laboratory and conducted by the Oak Ridge National
Laboratory (ORNL) concluded that composting can effectively reduce
the concentrations of explosives and bacterial. mutagenicity in
explosives-contaminated soil, and can reduce the aquatic toxicity
of leachable compounds. .The CCLT leachate toxicity to humans was
estimated by comparing the concentrations of TNT, RDX and HMX with
100 times their EPA Drinking Water Equivalent levels (a 100 fold
dilution of leachate in drinking water supplies was assumed, as in
RCRA) . The CCLT leachates from the composts met this criteria
indicating the toxicity to humans is not a serious concern The
ORNL noced that small levels of explosives and metabolites,
bacterial mutagenicity, and leachable toxicity do remain after
composting; however, they do not pose a serious health concern. In
fact, no mortality or toxic effects were observed in a rat oral
toxicity screen.
Chemical analysis of the finished compost indicated that the
nitro groups in_TNT were reduced to amino groups, producing first
the monoamino-dinitrotoluenes and then diamino-mononitrotoluenes
These metabolites have been shown to be less mutagenic than the
parent compound in previous studies. The observed TNT metabolites
did not quantitatively account for the decreases in TNT
concentrations. The ultimate fate of the biotransformed explosives
still remains unknown; however, extensive organic extraction and
alkaline digestion of a compost inoculated with radio-labelled TNT
suggested that a major portion of the bio trans formed TNT was
chemically bound to the compost and not mineralized. The nature
and significance of the biotransformation product-soil binding will
continue to be investigated.
UMDA Washout Lagoon Feasibility Studv
As the composting optimization study was concluding at UMDA in
1991, the Remedial Investigation (RI) of these washout lagoons was
also nearing completion. The washout lagoons soils were broken out
from the other sites in the RI and made the subject of a separate
Risk Assessment and Feasibility Study (FS) . An FS was conducted in
accordance with the Comprehensive Environmental Response,
316
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Compensation, and Liability Act of 1980, as amended by the
Superfund Amendments and Reauthorization Act of 1986. The FS
summarized the baseline risk assessment, the remedial action
objectives, screened potential remedial technologies and evaluated
in detail the most promising remedial technologies. Since there
are no federal cleanup standards for explosives contaminated soils,
the cleanup standards were developed based upon the remedial action
objectives in the Risk Assessment and the evaluation of various
treatment alternatives.
The remedial action objectives were used to determine a range
of soil volumes and treatment standards to be considered for
remediation. Four potential excavation scenarios, including a
cleanup to background, were considered thus providing varying
degrees of contaminant removal and risk reduction. The state
cleanup standard requires that soils should be cleaned up to
background if possible, or if not, to a level which is protective
of human health and the environment. Soil sample analysis within
the lagoons determined that 90% of the explosives contaminants were
in the 5 feet of soil below the bottom of the lagoons. Cleanup to
background (i.e., excavation to groundwater at 47 feet deep) was
evaluated, but the small amount of additional protection provided
would be very expensive ($14 million) . It was determined that
excavation of the soil to a depth of approximately 5 feet below the
lagoons to a cleanup standard of 30 parts per million for TNT and
RDX would reduce the excess lifetime cancer risk to 7 x 10"6 in a
future industrial land use scenario; well within the acceptable
ranges specified by EPA (i.e., between 1 xlO"* and 1 x 10"6) . This
represents a volume of soils of approximately 6,800 tons.
The remedial alternatives evaluated in detail were no action,
excavation followed by incineration, and excavation followed by
composting. Incineration is a proven method of destroying
explosives contaminants and could reduce the concentrations and
associated toxicity by 99.99 percent. Composting is an innovative
bioremediation technology for which extensive site-specific
treatability studies have been conducted. The optimization study
demonstrated the MAIV composting can reduce the TNT and RDX
concentrations by greater than 97 to 99 percent and reduce the
toxicity by 90 to 98 percent. Windrow composting is expected to be
comparably effective. Static pile composting was not considered
because of it's inability to meet the established cleanup criteria
in the treatability studies. The FS evaluated the cost of
implementing MAIV composting, windrow composting and incineration
for several excavation scenarios. Table 3 provides the estimated
cost of implementing these remedial alternatives at UMDA.
317
-------
The alternatives were evaluated for overall protection of human
health and the environment; compliance with applicable or relevant
and appropriate requirements (ARARs) ; long-term effectiveness-
reduction in toxicity, mobility, and volume; short-term
effectiveness; implementability; and cost. The no action
alternative failed to provide overall protection to human health
and the environment and did not comply with ARARs. The FS showed
that windrow composting would be expected to meet the remedial
action goals at a cost of approximately $2 million, as compared to
$4.1 million for incineration. The FS indicated that windrow
composting may be the most cost-effective application of this
technology due to the high capital costs of MAIV. Composting was
proposed to the public and regulatory agencies and was selected as
the final source control remedial action of the washout lagoons in
a Record of Decision on September 1992. A composting windrow field
demonstration is currently being conducted at UMDA to obtain design
information for the full-scale remediation contract. The U S Army
Corps of Engineers - Seattle District will initiate* the
implementation of the remedial action in 1993.
Conclusion
Composting is an emerging, innovative technology for the
remediation of explosives-contaminated soils. Treatability studies
have demonstrated that composting is able to reduce the
concentration of explosives (TNT, RDX and HMX) and associated
toxicity to acceptable health based clean-up levels. The UMDA
Washout f Lagoon FS has provided a cost analysis which indicates
composting is a cost effective alternative to incineration for
sites with less than approximately 20,000 tons of contaminated
soxl. The implentation of composting to remediate the explosives
contaminated washout lagoon soils at the U.S. Army Umatilla Depot
Activity will be the first application of bioremediation at an NPL
site for explosives-contaminated soils.
Army Technical
DRXTH-TE, Composting of Explosives, U.S. Army Report, DRXTH-TE,
Juy 82 »
AMXTH-TE-CR-86077, Composting Explosive/Organic Contaminated Soils
Atlantic Research Corp., May 1986.
318
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AMXTH-IR-TE-88242, Field Demonstration-Composting of Explosives-
Contaminated Sediments at the Louisiana Army Ammunition Plant
(LAAP), September 1988.
Evaluation of Composting Implementation: A Literature Review, TCN-
89363, July 1990.
CETHA-TS-CR-89276, Proceedings for the Workshop on Composting of
Explosives Contaminated Soils, September 1989.
CETHA-TE-CR-90027, Composting of Explosive-Contaminated Soil
Technology, October 1989.
Unnumbered Report, Evaluation of Composting Implementation, August
1990.
CETHA-TE-CR-91053, Final Report for the Composting Optimization
Field Study at Umatilla Army Depot Activity (UMDA) , November 1991.
ORNL/TM-11573, Phase I, Characterization of Explosives Processing
Waste Decomposition Due to Composting, .January 1990.
ORNL/TM-12029, Phase II, Characterization of Explosives Processing
Waste Decomposition Due to Composting, November 1991.
CETHA-BC-CR-92014, Risk Assessment for Explosive Washout Lagoons
(Site 4), Umatilla Depot Activity Hermiston, Oregon, March 1992,
CETHA-BC-CR-92016, Explosives Washout Lagoons Soils Operable Unit
Supplemental Investigation Technical and Environmental Management
Support of Installation Restoration Technology Development Program
Umatilla Depot Activity, Hermiston Oregon, April 1992.
CETHA-BC-CR-92017, Feasibility Study for the Explosives Washout
Lagoons (Site 4) Soils Operable Unit Umatilla Depot Activity,
Hermiston, Oregon, April 1992.
Contacts
Captain Kevin Keehan or Mr. Wayne Sisk
U.S. Army Toxic and Hazardous Materials Agency
ATTN: CETHA-TS-D
Aberdeen Proving Ground, MD, 21010-5401
(410) 671-2054 or DSN 584-2054
319
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Table 1; Amendment Mixture Composition and Cost
Amendment
Sawdust
Apple pomace
Chicken manure
Chopped potato
Horse manure/straw
Buffalo manure
Alfalfa
Horse feed
Cow manure
COST PER TON
Mixture A
30 %
15 %
20 %
35 %
$15
Mixture B
50 %
10 %
32 %
8 %
$200
Mixture C
22 %
6 %
17 %
22 %
33 %
$11
320
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Table 2: Results of Umatilla Composting Optimization Tests
Test
% Soil
static
pile
0
7
10
10
20
30
40
MATV
10
10
25
40
Amend-
ment
Mix
A
A
A
C
A
A
A
A
B
C
C
Initial
cone.
TNT
mg/kg
0
1144
1008
3850
5716
7908
9858
3452
3126
5208
6950
Final
cone.
TNT
mg/kg
0 .
107
200
41
331
174
2086
90
5.6
14 '
209
% Reduction
TNT RDX HMX
N/A
91
96
99
94
98
79
97
99
99
gr
N/A
73
46
93
16
22
0
90
99
97
18
N/A
'39
21
80
5
11
2
29
95
68
0
half-
life
days
0
6.6
6.4
6.9
14.8
16.1
24.9
5.2
'5.1
6.4
14.9
Table 3: Estimated Cost per Ton to Implement Remedial Alternatives
Depth of Excavation
Tons of Soil
2 Feet / 3,700
5 Feet / 6,800
20 Feet / 30,000
47 Feet / 47,000
Windrow
$386/ton
$288/ton
$206/ton
NAa
MATV
$651/ton
$481/ton
$330/ton
NAa
INCINERATION
$740/ton
$660/ton
$280/ton
$300/tonb
Notes: "Composting was not considered a viable alternative ror tnis
large volume of soil due to the requirements for large quantities
amendments. blncludes the cost for special construction techniques
used for vertical sided excavation.
321
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FIGURE 1: COMPOSTING PROCESS DESIGNS
U)
ts>
to
STATIC PILE COMPOSTING
MECHANICALLY AGITATED IN-VESSEL
COMPOSTING
WINDROW COMPOSTING
-------
FIGURE 2: COMPOSTING PROCESSES DEMONSTRATED DURING THE UMDA OPTIMIZATION STUDY
OJ
Deflector
\
On]
To Blower
Insulation
Wood Chips
AERATED STATIC PILE SCHEMATIC
Totally enclosed
reactor
MECHANICAL IN^VESSEL COMPOSTER
SCHEMATIC
-------
United States/German Bilateral Agreement on Hazardous Waste
Site Clean-up Projects
Stletzel, H.1, Sannlng, D.2, Berberich, 6.3, Steffens, K.3
1 Federal Ministry for Research and Technology, Refevat 523
Heinemannstr 2, 5300 Bonn 2, Germany
2 U.S. Environmental Protection Agency, RREL, 26 West Martin Luther
King Drive, Cincinnati, OH 45268, USA
3 Arbeitsgemeinchaft focon-PROBIOTEC - SchillingsstraBe 33 -
D-5160 Duren 5, Germany
324
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The problem of contamination to land and groundwater from improper
disposal of hazardous materials/waste are common to all industrialized
countries. Research and the development of technologies to deal with these
environmental problems is very costly and requires the highest level of
creativity and ingenuity. All countries resources and technical talents are
limited. Good researchers do not operate in a vacuum. Sharing technical
ideas and the expenses of developing new and innovative technologies for
dealing with contaminated land and groundwater appears to be a good idea based
on past experience. Cooperation at an international level is an economically
cost effective way to access hard-to-get and very worthwhile information. To
complicate the situation a wide variety of local and national circumstances/
factors lead to the development of varying standards and techniques used to
determine the effectiveness of various technologies to deal with these
environmental problems. In order to reduce environmental overload, close
international cooperation is indispensable, both in terms of measures
implemented and in the field of research and development, including the
exchange of information and experiences. Furthermore coordination of
environmental demands in different countries lessens the everpresent,
potential trade barriers and imbalances in competitiveness.
Against this backdrop a United States/German Bilateral Agreement on
hazardous waste site cleanup projects has been developed. The two lead
agencies are the United States Environmental Protection Agency (USEPA), Office
of Research and Development (ORD), and the Federal Republic of Germany (FRG),
Federal Ministry for Research and Technology (BMFT). By leveraging existing
resources and programs within the bilateral agreement each agency will enhance
the potential impact of these activities to the overall hazardous waste site
problems within their respective countries.
The goals of this bilateral agreement are:
• Facilitate understanding of each side's approach to the
remediation of contaminated sites ("as if-approach": as
if the foreign project had taken place in their own country)
• Demonstrate innovative remedial technologies
• Compare quality assurance programs
• Facilitate technology transfer
The technical approach to remediating a hazardous waste site is subject to a
different set of environmental and social factors in each country; therefore,
the usefulness of a particular technology can only be determined if it has
been evaluated in the light of these considerations within both countries.
Six sites on each side were selected for the cooperation. Detailed executive
summary reports on each of the German sites are being prepared by the
contractors working for the BMFT. These reports will be reviewed by
designated USEPA/RREL Technical Program Managers to determine what additional
analytical-type Quality Assurance (QA) and Quality Control (QC) measures
should be incorporated into the remedial action demonstration by the Germans
to meet the U.S. EPA Superfund Innovative Technology Evaluation (SITE))
criteria for determining the effectiveness of the individual technologies
being utilized at the sites.
The USEPA/RREL has prepared similar reports for the U.S. sites. The BMFT will
325
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review these reports to determine what additional analytical QA/QC measures
should be implemented into these remedial action demonstrations to meet German
criteria for determining the effectiveness of the individual technoloqies
being utilized at the EPA sites.
In the Federal Republic of Germany support for environmental related
research and development has a central function in the Federal Government's
environmental policy. In its environmental research program the Federal
Ministry for Research and Technology defined priority areas for the awarding
of research grants in fields particularly interfering with the environment.
The present promotion concept for the area of waste management and abandoned
hazardous sites (1989 - 1994) presents the future research and development
priorities in accordance with environmental priorities. In 1989 a special
program, the "Model remediation of representative hazardous waste sites" was
launched. The aim of this program is to develop further the state of the art
and to demonstrate new clean-up technologies as well as to assess their
applicability to actual hazardous waste sites. For the practical
demonstration the remediation projects are funded where physical-chemical -
thermal and biological techniques or combinations of these techniques are
applied. Special emphasis is given to their efficiency of clean-up, their
ability to generate a reusable soil, their costs and their environmental
impact. Six of these R&D projects were selected for the .EPA/BMFT bilateral
cooperation on hazardous waste site clean-up projects.
In order to obtain results within a given time frame the schedule of the
remediation projects affects the selection. The German project sites, the
remediation technologies being applied, and the types of contamination being
remediated are listed in table 1. (The technologies likely to start in 1993
and therefore that will be preferentially studied in the bilateral agreement
are underlined)
326
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Table 1: German Remediation Projects
German Sites
GASWERKE MUNCHEN
VARTA SUD,
Hannover
KERTESS, Hannover
HAYNAUERSTRASSE
58, Berlin
BURBACHER HUTTE,
Saabrucken
TNT STADTALLENDORF
Technologies
Soil-Washinq + Volume
Reduction of Residuals
Soil -Washing (+ Acid
Extraction)
Ground Water Pump +
Treat,
Soil Vapor Extraction
In-situ Soil-Washinq
Soil-Washinq.
Microbioloqy (ex situ).
Rotary Kiln Thermal
Treatment.
Fluidized Bed Inciner-
ation of Residuals
Thermal Treatment,
Soil -Washing,
Microbiology
Soil -Washing +
Incineration of
Residuals
Type of Contamination
PAH, Cyanides, Lead
Pb, Sb, As, Cd
CHC + Degr. Products,
CFC, HC, Honoaromatics
CHC, PHC,
Monoaromatics,
PAH, PCB, PCDD, PCDF
Sul fides, Cyanides, Pb,
Hg, Phenols, HC,
Honoaromatics
Munitions, TNT +
Degradation Products,
heavy metals
A brief description of the activities at these sites is as follows:
Gaswerke Munchen
The remediation of a former coal-gasification and gas-distribution facility in
Munich, Germany, is coordinated by an interdisciplinary working group
comprised of the site-owner, the city and state authorities and various
technical consultants. The entire site of the former gas-works is about 32.5
hectare (81.25 acres) in size and is located about 1 km northeast of the city
center. Various site investigations since 1982 showed that both the soil and
the ground water are contaminated with PAHs and the top most layer of soil is
further contaminated by lead. Slightly elevated concentrations of aliphatic
hydrocarbons and cyanides were found throughout the site, with some higher
peaks in limited areas. One of the hot-spots of the contamination (the "C 1
area", approx. 1 acre) was found to pose a substantial hazard to the ground
water and will be remediated in a first phase of the overall site remediation
which is subsidized by the Bundesminster fur Forschung und Technologie (BMFT).
Soil washing was identified to be the appropriate remediation technology.
25,000 t of gravel will be treated on-site using a soil washing process that
will be selected out of five optional technologies which are presently in an
off-site pilot scale testing-phase. The five plants apply batch processes
with or without detergents. Different systems are used for the separation of
327
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the clean soil from the contaminant bearing fines. To supplement the
treatment process, innovative treatment technologies like steam desorption and
vacuum distillation will be applied in parallel with soil-washing for the
treatment of the soil-washing residues.
Data on the contamination and the cleanup criteria identified are listed in
table 2:
Table 2
Pb
CN total
PAH
HC aliphatic
Soi 1 -Contami nati on
in mg/kg
maximum average
> 5,000 100 -1,000
> 1,000 > 50
> 7,000 < 500
> 10,000 < 500
Cleanup
soil
mg/kg
< 150
< 50
< 20
< 500
Criteria
eluate (pH7)
M9/1
-
< 50
< 0.2
VARTA-Sud, Hannover
The goal of this project is the remediation of the "Varta-Sud" area which was
contaminated by emissions from an adjacent battery factory between 1938 and
1989. The remediation of the site owned by the City of Hanover is being
coordinated by a consultant with the support of the "Varta-Sud Assessment
Group" which consists of independent scientists and engineers. The site is
located northwest of Hanover and covers an area of 4.5 hectare (approx. 11
acres). From October 1989 to April 1991 the site investigation was performed
showing lead, antimony and cadmium as main contaminants in the soil. Major
hot spots are deposits of sediments from a creek ("RoBbruchgraben") which was
used for waste water discharge by the battery factory. Slags from smelting
and coal firing are distributed unhomogenously throughout the area and are of
concern, as well as, landfills of debris, slags and residues from the battery
production. Besides the heavy metals, a PAH contamination of unknown origin
was detected in the south-eastern part of the site. The groundwater is not
yet substantially contaminated with heavy metals. Some typical values are
presented in table 3.
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Table 3
Pb
Sb
Cd
2 PAH
landfill material
maximum concentration
[rag/kg]
38,000
11,000
1,300
1,000
slag/soil mixture
range of concentrations
[mg/kg]
120 - 5,000
3 - 380
0.1 - 14
0.05 - 10
At present (November 1992), the results of investigations and trial runs of
different physical treatment technologies (water extraction, high pressure
soil washing, chemical extraction, or combinations) are being evaluated.
Concepts for the volume reduction of residues are designed. Decisions
concerning the further proceeding in the project are expected by winter 1992.
KERTESS, Hannover
The project involves the remediation of an industrial area which was used for
the handling and storage of organic solvents and detergents, as well as
aromatic and halogenated hydrocarbons from 1946 until 1985. The owner of the
site is the DB German Railroad (Deutsche Bundesbahn). The area is about 1
hectare (2.5 acres) in size and is located in the southern part of the City of
Hannover. Site investigations in 1975 detected groundwater contamination and
in 1976 the first remediation attempt (groundwater extraction and treatment)
started. Due to the lack of efficiency of these measures the project
management was reorganized and a new remediation concept was designed.
Major contaminants are chlorinated and aromatic solvents found in the vadose
zone and on the bottom of the underlying aquifer (DNAPL). Table 4 lists
average concentrations of selected contaminants as well as cleanup criteria
identified by the State Secretary of Environment:
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Table 4
trichloroethene
perch! oroethene
chloroform
vinyl chloride
benzene / toulene
2 CHC / 2 VOC*
2 BTX
Cleanup Criteria
2 CHC
ground water [mg/m3]
4,160
6,050
65
410
110 / 310
18,300 / -
1,220
< 10 - 20 mg/m3
soil gas [mg/m3]
4,185
2,150
80
120
230 / 270
- / 14,935
200
< 1 mg/m3
* chlorinated
Berlin: Haynauer Str.58
The site "Haynauer StraBe 58" is situated in the south of Berlin, in the
district of Steglitz and has an overall size of 3,100 m The site was used
for the reconditioning of solvents, chemical wastes and waste oils. The
contamination of the site happened between 1952 - 1960. In 1980, the company
was closed down. Major contaminants are petroleum hydrocarbons (PHC), BTEX,
volatile chlorinated hydrocarbons (CHC), polychlorinated biphenyls (PCB),
PCDD/F were found in the debris of demolition works.
Clean-up standards for soil are fixed by the "Berlin List":
• petroleum hydrocarbons (PHC)
BTEX
• total high-volatile chlorinated
hydrocarbons (CHC)
• total PCBs
150 mg/kg
2.5 mg/kg
2.5 mg/kg
0.5 mg/kg.
For ground water the following clean-up standards are fixed:
CHC
• BTEX
. PHC
* PCBs
25
10
250 /ig/1
0.25 iig/1.
The remediation concept for this site is a combination of different individual
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technologies:
• PCDD/F-contaminated debris are treated thermally in a rotary kiln
• full-scale, off-site soil washing plant will be used for the main
portion of the contaminated soil (40,000 t)
• residuals will be incinerated in a fluidized bed process or treated
microbiologically
• slightly contaminated soil will be treated microbiologically
• full scale soil vapor system is used for the decontamination of soil
vapor
• ground water is treated.
The soil of the site will be excavated emission-free in three phases.
Remediation phase 1 was started in fall 1991 and finished in August 1992. In
this step an overall contained third of the site (approx. 700 m ) was
excavated to a depth of 7 m below ground level. An amount of 7,100 m3 soil
was treated by soil washing, 600 t microbiologically.
reembedded on site.
The cleaned soil was
Soil vapor extraction has been performed since 1990. In the first half of
1993 the thermal treatment process will be started for the residuals and
debris as well as the ground water treatment.
In fall 1992 the 2nd remediation phase was prepared. About 1,600 m2 of the
site was covered in order to avoid emissions during excavation. Work was
finished in October 1992. Soil excavation was started in November 1992.
Again the contaminated soil is treated by soil washing and microbiologically.
Burbacher Hutte
The "Burbacher Hutte", founded in 1857 is located in the western part of
Saarbriicken. In times of peak productivity the Burbacher Hutte reached its
maximum size with approx. 60 ha (600,000 m).
Contamination of the soil started when the steelworks was founded in 1857 and
continued until the end of the 1980's when all production plants were
demolished. In the past, there were different individual production plants,
e.g. coke factories, benzene works, gas generation plant etc. which caused
specific contamination at the Burbacher Hutte site. The following main
contaminants were found in different parts of the site:
BTEX
phenols
PAHs
heavy metals (e.g. lead and mercury)
sulfides and cyanides.
In addition, in some areas of the site ammonium has been detected at elevated
concentrations.
In 1991 - 1992 full-scale pilot-tests were performed with different
technologies on-site and off-site:
• soil extraction
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• bioremediation
• soil washing and
• high temperature incineration.
At present the results of these pilot-tests are being evaluated. The
remediation concept will be a combination of these different technologies for
the various, individual groups of contaminants.
A decision on a suitable combination of technologies is expected to be made in
late fall of 1993. Start of the actual remediation will be in 1994 after
passing the permitting process.
Stadtallendorf
The former ammunition and explosives factory Stadtallendorf is located approx.
100 km north of the city of Frankfurt. The production area of the former DAG-
site had a size of ca. 4.2 km with 413 buildings having an overall base of
ca. 62,000 m . In March 1941, the TNT production was started. Within the
following 3 years the production raised from zero to 5,400 tons per month.
The overall production and processing amounted to ea. 126,000 tons of TNT and
27,000 tons of other explosives. Production stopped on March 28, 1945. After
World War II the U.S. Army used the site as storage for ammunition, gear and
tools. Between 1946-1949 almost all production plants were demolished or
blasted. Today, the site of Stadtallendorf is mainly characterized by mixed
use including residential areas, industrial sites and the former ammunition
and explosives factory. About 3,000 inhabitants of Stadtallendorf are living
and working in the former bunkers or in the converted production buildings or
related facilities remaining on the site.
Between 1938 and 1945 the site of the ammunition factory was contaminated
with:
• explosives, e.g. TNT, H.N.D., RDX;
« raw materials and pre-fabricates of the explosives production, e.g.,
toluene, mono-and dinitrotoluenes;
• degradation products, e.g. (di-)nitro-aminotoluenes;
• miscellaneous pollutants like phenols, heavy metals and others.
Contamination of soil and groundwater at Stadtallendorf was caused by unsafe
production methods, uncontrolled waste disposal, insufficient waste water
treatment, accidents, leakages and others.
The envisaged remedial technology for contaminated soil is a combination of
soil washing with a high-temperature combustion of the contaminant-bearing
residues. For soil decontamination the clean-up targets are defined as
1 mg/kg for explosive-related contaminants. Soil washing and thermal treatment
is to be started in 1995.
At present additional investigation of a 6 ha hot spot area are being
conducted. In a trianguarily shaped grid additional borings are being carried
out at the former production plants (TNT Groups 1-3 ruling plants). First
results indicate that the main contamination with varying concentrations was
found at a depth of 0-lm below ground level. The detailed results of this
investigation phase will be the foundation of the future remedial concept.
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Furthermore, a new analytical method for the analysis of TNT by means of HPLC
and electro-chemical detection was performed by a scientific expert team
because there was no analytical standard procedure for TNT in Germany This
analytical method will be published in January 1993.
The United States sites are summarized with their main characteristics
in table 5.
Table 5. U.S. Remediation Projects
U.S. Sites
Waukegan Harbor Site
(Outboard Marine
Corp.), IL
Kelly Air Force Base
San Antonio, TX
Electro-Voice NPL
Site Buchanan, MI
Lawrence Livermore,
Site 300, GSA
Altmont Hill, CA
Indiana Wood
Preservers Site
Bloomington, IN
Pennsylvania Power &
Light (PP&L) Brodhead
Creek Site
Stroudsburg, PA
Technologies
Anaerobic Thermal
Treatment on Site
Radio Frequency
Induced Heating
Subsurface
Volatilization and
Ventilation System
(SVVS)
Advanced Oxidation,
Perox-Pure
Bioremediation
Contained Recovery of
Oily Waste (CROW)
Types of
Contamination
PCB, Oil & Grease
VOC'S, SVOC'S, TPH
BTEX, PCE, TCE, 1,
1-DCE
VOCs, TCE, PCE
Creosote/Coal Tar,
PAHs Naphthalene,
Anthracene
Organic Liquids, Coal
Tars, PAH, Phenols
A brief description of these activities at these sites is as follows:
Outboard Marine Corporation (OMC), Waukegan, Illinois
Outboard Marine Corporation (OMC) used PCBs as a hydraulic fluid at the
Waukegan Harbor facility. As a result of leaks and spillage major parts of
Waukegan Harbor's 37 acres and parts of the manufacturing facility were
contaminated with PCBs up to 10,000 ppm (mg/kg). The OMC site remediation
included dredging and excavating the PCB contaminated sediments and soils;
treating the high PCB concentration soils and sediments; and placing low
concentration PCB soils and sediments in one of several isolation cells.
Thermal desorption was the selected treatment technology for the high
concentration PCB soils and sediments. SoilTech's Anaerobic Thermal Processor
(ATP) treated these solids after natural dewatering occurred. The ATP system
mixes and heats the solids in the processing unit, which consists of four
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zones; preheat, retort, combustion and cooling. Temperatures in the preheat
zone (400 - 650 ) cause the water and volatile organic compounds (VOCs) in the
solids to vaporize. The higher temperatures in the retort zone (900 -
1,150 F) cause (1) heavy organics to vaporize and (2) thermal cracking of
hydrocarbons creating coke and low molecular weight gases. In the combustion
zone the coked solids are combusted and either recycled to the retort zone or
passed into the cooling zone. Gases from the preheat and retort zones are
cooled and condensed to recover the water and organics; while the
noncondensable organics are burned in the combustion zone.
In June 1992 a USEPA SITE Demonstration was performed on the Soil Tech ATP
system operating at the OMC Waukegan facility. Three replicate test runs were
conducted at the typical operating conditions used during the OMC site
remediation. Each test run consisted of 8.5 hours of solids and liquids
sampling and 8 hours of stack sampling. A total of 224 tons of PCB
contaminated soil and sediment was treated during the Demonstration.
Extensive process operating data were collected to document the ATP operating
conditions. Key findings from the OMC/SoilTech SITE Demonstration included:
1) PCB concentrations were reduced from an average of 9,761 ppm in the
untreated solids to an average of 2 ppm in the treated solids.
2) Approximately 0.12 milligrams of PCBs were discharged from the ATP stack
per kilogram of PCBs fed to the ATP (0.12 mg/kg or 99.9999% ORE).
3) The majority of PCBs removed from the solids during treatment were
accumulated in the organic storage from the gas condensation.
4} No dioxins, other than a low concentration (0.1 nanograms (ng) per dry
standard cubic meter (dscm) of octachlorinated dioxin, were detected in
the stack gas from the ATP system. Tetrachlorinated furans were found
in both the untreated (88 ng/g) and treated (5 ng/g) solids and the
stack gas (0.07 ng/dscm).
5) teachable VOCs, semi volatile organic compounds (SVOCs) and metals in the
treated solids were below RCRA toxicity characteristic standards.
6) No operational problems affecting the ATP's ability to treat the
contaminated solids were observed.
KELLY AIR FORCE BASE - San Antonio, Texas
Site S-l, located near the northern boundary of Kelly Ait Force Base was
used from 1960 to 1973 as an intermediate storage area for wastes awaiting
off-base reclamation. Waste liquids consisting of mixed solvents, carbon
cleaning compounds and petroleum oils and lubricants were hadled here. Spills
and storage tank flooding resulted in soil contamination from these chemicals.
At the conclusion of waste handling operations in 1973, the area was
backfilled and regraded. This resulted in soil contamination at depths of up
to 27 to 30 feet. The vadose zone extends to this depth.
Volatile and Semi-volatile organic contamination at the site occurs at
concentrations ranging from 8.5 to 104,000 ppb. Total Petroleum Hydrocarbon
(TPH) concentrations range from 20 to 17,000 ppm. Specific contaminants found
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at the site include a variety of short chain chlorinated hydrocarbons such as
1,2-Dichlorobenzene, 1,4-Dichlorobenzene and 1,3-Dichlorobenzene, aromatic
hydrocarbons such as benzene, ethyl benzene, chlorobenzene and styrene and
polycyclic aromatic hydrocarbons such as Dibenzo Anthracene, Benzo Pyrene and
Benzo Fluoranthene. Some very low concentrations of PCBs have also been
detected.
In-Situ Radio-Frequency Heating will be studied at site S-l to determine
its efficacy in removing volatile and semi-volatile organic contamination from
vadose zone soils. This technology was developed by the Illinois Institute of
Technology Research Institute (IITRI) and will be demonstrated for the Air
Force with the assistance of Haliburton NUS. The system consists of a 120kW
RFH power source, excitor and ground electrodes, a vapor barrier and a vapor
treatment system.
For the test, the excitor and ground electrodes will be placed in the
ground at S-l in a predetermined array. Thermocouples will be placed in the
ground with the electrodes to monitor ground temperature. Heat generated by
radio-frequency radiation will heat the soil to approximately 150 C. The
elevated temperature combined with steam distillation resulting from the
vaporization of soil moisture will sweep organic contamination from soil. A
vacuum will be maintained on the soil area under treatment in order to capture
released contamination. A vapor barrier installed atop the soil treatment
area will prevent the release of contaminant laden gasses to the atmosphere.
These gasses will be.captured by the vapor barrier and treated by both
condensation and carbon filtration.
Development of the demonstration plan is currently under way. Electrode
placement and pre-test soil sampling should occur in early 1993. System set up
and treatment of 500 cubic yards of contaminated soil from S-l will take place
in mid-1993. Post test soil sampling will be completed by the end of July
1993. Data analysis and reporting will be completed as soon as possible
thereafter.
SVVS Demonstration, Buchanan, Michigan
This SITE Program Demonstration will assess the effectiveness of the Soil
Volatilization and Ventilation System™ (SVVSK) developed by Billings & Assoc.,
Inc. of Albuquerque, NM and offered under license through Halliburton NUS.
The technology is a combined air-sparging/soil-vacuum-extraction technique
which moves air into the water table through injection wells and draws air
from the vadose zone through extraction wells. At some installations, one
injection and multiple vacuum wells are placed in the same soil boring,
resulting in a "well nest." In this installation, injection and vacuum wells
are placed in individual borings. The movement of air through the subsurface
stimulates the activity of aerobic microorganisms resulting in a quicker
remediation of organic contamination than by soil vacuum extraction (SVE)
alone. Vapors collected in the SVE portion of the system can be treated in
Biological Emissions Control™ (BEC™) units reducing or removing the need for
carbon adsorption or other expensive emissions controls.
The Demonstration site chosen is the Electro-Voice site, a Superfund
(National Priority List [NPL]) site in Buchanan, Michigan. This site in
southwestern Michigan is an operating factory producing electrical sound
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amplification equipment. Formerly, liquid painting residues were discharged
to a "drywell," a lined pit backfilled with gravel, next to the factory
facility. This practice was discontinued and the drywell filled with soil and
construction debris in 1973.
Sampling conducted during the NPL process revealed a sludge-like layer
at the bottom of the former drywell. Initially, peak soil concentrations were
observed for alky!benzenes (454,000 ppb), benzene (350 ppb), 2-butanone (4,900
ppb), 1,1-dichloroethane (200 ppb), l,2(cis)-dichloroethene (200 ppb)
ethyl benzene (95,000 ppb), styrene (3,400 ppb), tetrachloroethene (14,000
ppb), toluene (330,000 ppb) trichloroethene (590 ppb), and total xylenes
(710,000 ppb). During sampling prior to the Demonstration, peak soil
concentrations were sought for toluene (96,000 ppb), ethyl benzene (64,000
ppb), m,p-xylene (190,000 ppb), o-xylene (29,000 ppb), benzene (210 ppb), 1,1-
dichloroethene (130 ppb), trichloroethene (18,000 ppb), and tetrachloroethene
(16,000 ppb).
The SVVS™ technology is to be evaluated for its ability to meet a
claimed 30% reduction in seven combined contaminants (benzene, toluene,
ethylbenzene, xylene [BTEX], tetrachloroethene [PCE], trichloroethene [TCE],
and 1,1-dichloroethene [DCE]) in the vadose zone within 12 months of
operations. Further, data collected during the SITE Demonstration will
investigate the relative contribution of the two primary mechanisms of
removal: bioremediation and air-stripping. Finally, the effectiveness of the
BECW unit at meeting State of Michigan air emissions standards will be
evaluated. Vinyl chloride levels in the soil will also be monitored. In
order to assess the claimed 30% reduction, twenty soil borings will be located
within the 113 m area before the start of operation, and twenty more soil
borings will be obtained following 12 months of operation. From each soil
boring, seven soil samples will be obtained for Volatile Organic Contaminant
(VOC) analysis with special quality assurance/quality control measures
performed for the seven "critical analytes" and vinyl chloride. Analyses of
the gasses entering and leaving the BEC™ unit will be conducted periodically
throughout the 12 months. Additionally, soil gas measurements, groundwater
analyses, soil VOC levels from the saturated zone, and in-situ biological
respiration data will be obtained.
Lawrence Livermore National Laboratory; Site 300 Demonstration,
Altamont Hill, California
The perox-pure™ technology is designed to destroy dissolved organic
contaminants in groundwater or wastewater through an advanced chemical
oxidation process using ultraviolet (UV) radiation and hydrogen peroxide.
Hydrogen peroxide is added to the contaminated water, and the mixture is then
fed into the treatment system. The treatment system contains four or more
chambers in the reactor. Each chamber contains one high-intensity UV lamp
mounted in a quartz sleeve. The contaminated water flows in the space between
the chamber wall and the quartz tube in which each UV lamp is mounted.
UV light catalyzes chemical oxidation or organic contaminants in water
by its combined effect upon the organics and reaction with hydrogen peroxide.
First, many organic contaminants that absorb UV light may undergo a change in
their chemical structure or may become more reactive with chemical oxidants.
Second, and more importantly, UV light catalyzes the breakdown of hydrogen
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peroxide to produce hydroxyl radicals, which are chemical oxidants.
Site Description:
Site 300 is a high-explosive test area, established by LLNL in 1955. It
is comprised of 11 square miles and is about 60 miles east of San Francisco,
and 15 miles east of Livermore, California. Operations at Site 300 include
hydrodynamic testing; charged particle beam research; physical, environmental,
and dynamic testing; and high-explosive formulation and fabrication. The
demonstration took place in a section of Site 300 called General Services Area
(GSA). This area is contaminated with VOCs, including trichloroethane (TCE),
tetrachlorethane (PCE), 1,1-dichloroethane (1»1DCE), 1,2-dichloroethane (1,2-
DCE), and 1,1,1-trichloroethane (1,1,1-TCA).
Additional monitoring measures included the following:
• VOC Purge and Trap GC-MS (method 8240), additionally to the target
compounds, TIC (10 largest peaks) are identified applying NBS-search
• SVOC Method 8270 (GC-MSO, additionally to the target compounds, TIC (10
argent peak?) are identified applying NBS-search.
« AOX/TOX During each run of the plant at the fed-line and at the
effluent-line on sample each is taken for TOX (method 9020). "AOX"
including the purging step was performed with 20% for the samples
additionally. Thus, a basis for a comparison between the two methods
will be available, the risk of errors due to poor data quality is
minimized. A summary of the results will be supplied.
Indiana Wood Preservers (IWP) Site, Bloomington, Indiana
The IWP site was operated from 1976 to 1987. A solution of
creosote/coal tar was used as an agent for preservation of railroad ties. IWP
utilized the Boulton process which involves the application of an initial
vacuum, the pressure impregnation of the creosote/coal tar solution into the
railroad ties. There is a total of 35,000 gallons of liquid and 355 cubic
yards of sludge/contaminated soil existing in two holding ponds, as well as
890 cubic yards of contaminated debris in a waste pile on site.
Bioremediation was chosen for the treatment of the contaminated soils
removed from the holding ponds. Because of the limited amount of space
available at the site, it was decided that the biodegradation would take place
in constructed compost piles. This treatment process would also add
additional organic sources to allow co-metabolism to assist in the degradation
as well as the direct mineralization of the polynuclear aromatic hydrocarbons
(PAHs) present in the contaminated soil. Preliminary studies were conducted
degraded.
The compost piles are made of a mixture of 17 parts of soil, 4 parts of
horse manure, and one part of straw. Each compost pile is 20 meters long, 10
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meters wide, and 2.5 meters high. As the pile was being built, hollow plastic
piping was placed from the outside of the pile leading into the heart of the
pile. This piping was added all around the pile and at different heights in
order to allow air into the pile to supply oxygen for the microbial
degradation of the PAHs. Laboratory studies had shown an average oxygen
consumption rate of 64.8 mg 02/kg hour.
The compost piles have been built and are in operation. The analytical
test results have not yet been received. Consideration is being giverv to a
series of treatments consisting of biological treatment, followed by chemical
treatment with Fenton's reagent (hydrogen peroxide and ferrous iron salt,
which is a powerful radical oxidant), followed by additional biodegradation to
attempt to bring the final PAH concentration of the treated soil to a level
significantly below that which could be achieved by biodegradation alone.
Pennsylvania Power and Light (PP&L), Brodhead Creek Site,
Stroudsburg, Pennsylvania
The Brodhead Creek Superfund site in Stroudsburg, Pennsylvania has been
selected for the demonstration of the contained recovery of oil wastes (CROW)
process. The primary contaminant at the site is coal tar produced as a
byproduct of a coal gasification plant. Identifiable contaminants include
benzene, polynuclear aromatic hydrocarbons (PAHs), and phenols. A large
amount of coal tar has migrated through the surficial aquifer and is now
pooled in a depression approximately 6 meters wide and 18 meters long. The
aerial extent of the pooled coal tar will be better defined during a predesign
sampling effort tentatively scheduled for early December 1992.
The CROW process was selected in a record of decision (ROD) as an
interim remedy to reduce the amount of free coal tar pooled at the base of the
aquifer. The CROW process will use a system of injection and recovery wells to
remove the coal tar. Water heated to a temperature of approximately 90
degrees Celsius will be injected at the base of the aquifer through sic to
eight injection wells on all sides of the pooled coal tar. Dual completion
recovery wells located in the center of the coal tar pool will be used to
recover ground water and coal tar. The lower completion recovery well is
designed to recover the injected water and coal tar; the upper completion
recovery well is intended to maintain a copy of cooler ground water over the
treatment area. The maintenance of a cool water cap over the treatment area
is intended to prevent contamination from migrating into the unsaturated zone.
The fluids produced from the recovery wells will be sent to an oil-water
separator for treatment. Most of the outflow water from the oil-water
separator will be reinjected by the CROW process, while the remainder of the
water will be treated in a bioreactor and discharged to Brodhead Creek. If
the water does not meet the requirements of a National Pollutant Discharge
Elimination System (NPDES) permit, treatment in the bioreactor will be
followed by carbon adsorption. The U.S. Environmental Protection Agency (EPA)
Region 3 has set the cleanup criteria at 60 percent removal of the free coal
tar measurable in monitoring wells. Remediation Technologies, Inc. (ReTech),
the prime contractor supervising the remedial effort for the potentially
responsible parties, has indicated that the CROW process will be operated
until the amount of recovered contamination has stabilized.
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The Superfund Innovative Technology Evaluation (SITE) program will
monitor all phases of CROW process installation, operation, and post-operation
sampling. The steps that will be undertaken to design and build the CROW
process include predesign sampling, process design, construction, and
operation. If the current schedule is followed, the predesign sampling will
occur in December 1992, the design will be completed by May 1993, construction
will be completed by the end of July 1993, and the system will be operated
from August 1993 through October and possibly into December 1993. During the
predesign sampling, the SITE program will collect samples of the site soil and
pure coal tar. The samples will be used to refine and validate the analytical
methods. The SITE program demonstration will include soil and ground-water
sampling and monitoring of operational parameters. Soil samples will be
collected before and after the CROW process operation to determine the
reduction of subsurface contaminants. The ground water, injected water, and
recovered water will be sampled to determine the amount of contamination
recovered. During CROW process operation, the SITE program will monitor
pumping rates' injected, recovered, and ground-water temperatures; and water
levels. The data collected will be used to evaluate the effectiveness of the
CROW process at the Brodhead Creek Superfund site and to determine the factors
that will affect the CROW process at other sites.
Acknowledgement: The authors would like to express their appreciation to the
following Project Managers from the Risk Reduction Engineering Laboratory for
their technical contributions:
Kim Kreiton
Paul dePercin
Ron Lewis
Norma Lewis
Laurel Staley
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Groundwater Remediation: Extraction and Removal of TCE & Cr6* at an NPL Site
Subijoy Dutta, P.E.,
' U.S. EPA, OSW/CAPB/PSPD/ATS, OS-341; 401 M St. SW, Washington D.C. 20460.
Phone: 202-260-1371; FAX #202-260-0096
This case study focuses on the engineering analysis of a treatment process used in a
National Priority Listed (NPL) site in a midwestern State within the continental United States. The
primary contaminants intended to remove from the groundwater at this site are Trichloroethylene
(TCE) and hexavalent chromium (Cr6+)
The groundwater treatment plant, for this site belonging to an aircraft repair and paint
company, is designed for a flow rate of 150,000 gal./day (567 m3/day). The cleanup period is
estimated to be 30 years. The treated water is planned for industrial reuse at the same facility.
The waste characteristics of this NPL site are very common to many aerospace industries
and other industrial sites. The cleanup method used at this site for TCE and Cr6+ removal could
be used in similar other sites since it renders a high (99.99%) contaminant removal efficiency and
offers an environmentally clean method with very minimal sludge/waste generation.
Based upon the result of a study, involving a complete engineering analysis of several
different processes that are available for removal of organics, mainly trichloroethylene-(TCE), and
metals, primarily hexavalent chromium (Cr6*), the following treatment train was selected for this
NPL site.
+ Organic Removal Process
* Metals Reduction Process
+ Metals Precipitation process
* Final polishing process
below:
The treatment processes for the groundwater treatment plant (GWTP) are summarized
1 . The Organic Removal process consists of the Aquadetox system, developed by Dow
Chemical and patented for removal of high boiling organic compounds. This process has been
found to be effective in removal of most of the organic compounds, which are listed as hazardous
by the U.S. Environmental Protection Agency (EPA). The stripping technology, whether an air
stripper or a steam stripper, can provide 99.9999% removal efficiency. The effluent from this
process is expected to have non-detectable concentration (less than 1 ppb) of the organic
contaminants. The Aquadetox process is also accepted under the EPA's Superfund Innovative
Technology Evaluation (SITE) program. This technology, working at over 10 locations, eliminates
any carbon polishing of the effluent water. The conventional air stripping provides only about 90-
95% removal of volatile organic compounds.
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2. The Metals Removal Process consists of the following:
" The incoming groundwater contaminated with hexavalent Chromium (Cr6+) is treated by
a reduction process first. This reduces the Cr6* to the trivalent form, Cr3+. The metal is then
removed as precipitate from the groundwater.
In the first stage of treatment, the pH is lowered to 2.5 by the addition of 98% Sulfuric acid
(H2SO4); a pH probe in the tank controls this addition. The stream is made acidic to facilitate the
reduction reaction. The reducing agent to be used in the process is sodium metabisulfite
.3 +
. This chemical reduces the hexavalent chromium, Cr , to trivalent chromium, Cr
The automatic addition of sodium metabisulfite is controlled by an Oxidation Reduction
Potential (ORP) measuring instrument. Proper reduction of chromium can be seen readily by a
color change from yellow to blue in the treatment tank.
After being reduced, the stream from the first stage flows to the second stage tank for
primary precipitation treatment. The pH is raised to 9.0 to precipitate the trivalent chromium as a
chromium hydroxide. This is accomplished by adding a 50% sodium hydroxide solution; the
amount of addition is controlled by a pH probe. Chromium is an amphoteric metal which means
that it is highly soluble at both a low pH as well as at a high pH. For this reason the pH is
maintained at the optimum value of 9.0. Practically, this value can not be precisely controlled due
to the addition of the sodium hydroxide in large quantity. If the pH differs greatly from this value,
excess trivalent chromium remains in the solution. At a pH of 9.0 the trivalent chromium and other
heavy metals precipitates as metal hydroxides. The sludge generated by this process is expected
to be 75% less than that generated by the Ferrous Sulfate process, which is commonly used in
old metal processing/plating industries,
A secondary precipitation of these metals occurs in the pH adjustment tank, where the pH
is maintained at 9.0 (for further precipitation) by adding sodium hydroxide or sulfuric acid as
required. Thus if the pH goes to a value of 10.0, it is lowered to 9.0 by adding sulfuric acid.
Likewise, if the pH falls to 8.0, sodium hydroxide is added to raise the pH to 9.0. This addition
is controlled by a pH probe located within the tank. The precipitated metal hydroxides exists as
light density particles.
The treated water is then transferred to the flash mix tank of the clarifier, using a centrifugal
pump. The pumping is controlled automatically by a level monitoring probe which cycles the
pump on or off. To promote flocculation, a polyelectrolyte is added to the stream.
The effluent from the precipitation process has a chromium concentration of about 20-50
parts per billion (ppb). The effluent then passes through the final polishing process to further
reduce the concentration of chromium and other heavy metals to 10-15 ppb.
3. The Fine Filtration Process involves a Polymer Enhanced Cross Flow Sand Filtration.
341
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This sand filtration system.Dynasand™ is a patented process. It has some unique features in sand
filtration. It is a continuous, backwash, upflow, deep and granular media filter. The filter media is
continuously cleaned by recycling the sand internally through an airlift pipe and sand washer. The
regenerated sand is redistributed on top of the sand bed allowing for a continuous uninterrupted
flow of filtrate and reject water.
Feed is introduced into the bottom of the filter, then flows upward through a series of riser
tubes and is evenly distributed into the sand bed through the open bottom of an inlet distribution
hood. The influent flows upward through the downward moving sand bed with solids being
removed. The clean filtrate exits from the sand bed, overflows a weir, and is discharged from the
filter. Simultaneously, the sand bed, along with the accumulated solids, is drawn downward into
the suction of an airlift pipe which is positioned in the center of the filter. A small volume of
compressed air is introduced into the bottom of the airlift. The sand, dirt, and water are
transported upward through the pipe at a rate of about 200 gpm/ft2. The impurities are scoured
louse from the sand during this turbulent upward flow. Upon reaching the top of the airlift, the
dirty slurry spills over into the central reject compartment. The sand is returned to the sand bed
through the gravity washer/separator, which allows the fast settling sand to penetrate, but not the
dirty liquid. The washer/separator is placed concentrically around the upper part of the airlift and
consists of several stages to prevent any short circuiting. By setting the filtrate weir above the
reject weir a steady stream of clean filtrate flows upward, countercurrent to the sand, through this
washer section and acts as a liquid barrier that carries away the dirt and reject water. Since the
sand has a higher settling velocity than the dirt particles, it is not carried out of the filter. The sand
is redistributed by means of a sand distribution cone. The sand bed is continuously cleaned while
both a continuous filtrate and a continuous reject stream are produced.
For an effluent of 10 ppb to 20 ppb at a flow rate of 65 to 70 gpm, a Filter with a Polyblend
emulsion polymer feed system is recommended for the polishing process. This proven process
has been successfully used at an AT&T plant in Mesquite, Texas and in a Groundwater treatment
plant of Stauffer Chemical Co. in Martinas, California. The effluent chromium level of 10 ppb was
attained by using just the sand filters at that treatment facility. A simplified flow chart of the
proposed groundwater treatment process is shown on Rgure 1.
342
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A
Carbor
Beds
^
Clear
Emiss
*
. I
T Ste^m Cond.
1 1
Stripping Tower
u
Solvent
Storage
Metals
Removal
Process
Sand
Filtration
Unit
Filter Press
Clean
Affluent
to
Industrial
Reuse
FIGURE l Flow chart of the proposed groundwater treatment plant
-------
The annual operating cost of this system is very low compared to the reverse osmosis or
ion exchange systems, since the Dynasand™ system gets continuously regenerated. The only
operational cost involved in this process is the electric utility cost and the polymer cost. Labor cost
is minimal in this operation.
The automated control mechanism routes the water through the optional polishing process
if, and only if, the concentration of chromium in the effluent is over 50 ppb, or any other desired
value. The polishing process involves fine filtration. The whole process is completely automated
which cuts down a significant cost of this long-term cleanup operation.
REFERENCES
1. Aldrich, James R., "Effects of pH and proportioning of Ferrous and Sulfide Reduction
Chemicals on Electroplating Waste Treatment Sludge Production", Proceedings of the 39th
Annual Purdue Industrial Waste Conference, West Lafayette, IN, May 1984.
2. Christensen, Erik, R., and Delwiche, John, T. "Removal of Heavy Metals From Electroplating
Rinsewater by Precipitation, Flocculation, and Ultrafiltration", Water Research, Vol. 16 (1982)
p. 730-744.
3. Collie, M.J. "Industrial Water Treatment Chemicals and Processes Developments since
1978", NDC Publications, NJ 1983. Chemical Technology Review No. 217, Pollution
Technology Review No. 98, 1983.
4. Cushnie, George C., Jr. "Electroplating Wastewater Pollution Control Technology", Pollution
Control Review No. 115, Noyes Publications, 1985.
5. DeFilippi, Richard P., "Ultrafiltration", a part of "Filtration, Principles and Practices, Part I",
Mercel Dekker Inc., New York and Basel, 1980, p. 475.
6. Eilbeck, WJ. and Mattock, G. "Chemical Processes in Waste Water Treatment" Ellis
Norwood Limited, England, 1987.
7. Faust, Samuel D., and Aly, Osman, M. "Chemistry of Water Treatment", Butterworth
Publishers, 1983.
8. Fisco, R., "Plating and Industrial Waste Treatment at the Expanded Plant of Fisher Body,
Elyria, OH", Proceedings of the 25th Purdue Industrial Waste Conference, Purdue
University,
May 1970.
9. Fresenius, W. and Schneider, W. "Waste Water Technology", Springer-Verlag Berlin
344
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Heidelberg, 1989.
10." Germain, J. , Vath, C., and Griffin, C., "Solving Complex Waste Disposal Problems in the
Metal Finishing Industry", Presented at the Georgia Water Pollution Control Association
Meeting, Sept. 1968.
11. Glynn, W., Baker, C., LoRe, A., and Quaglieri, A. "Mobile Waste Processing Systems and
Treatment Technologies", Pollution Technology Review No. 147, 1987.
12. Gould, J. "The Kinetics of Hexavalent Chromium Reduction by Metallic Iron", Water
Research, Vol. 16 (1982), p. 871-877.
13. Henold, Kenneth L, and Walmsley, Frank "Chemical Principles, Properties, and Reactions",
Addison-Wesley Publishing Company, 1984.
14. Middlebrooks, E. Joe "Water Reuse", Ann Arbor Science Publishers Inc., 1982.
15. Naval Facilities Engineering Command (NFEC), Technical Memorandum no. 71-85-01,
"Manufacturer/user study of selected recovery-related plating technologies", Port Hueneme,
California, October 1984.
16. Patterson, James, W., "Industrial Wastewater Treatment Technology", second edition,
Butterworth Publishers, Boston, 1985.
17. USEPA, "Treatability Studies for the Inorganic Chemicals Manufacturing Point Source
Category", Publication no. 440/1-80/103, July 1980.
18. USEPA, "Development Document for Effluent Limitations Guidelines and New Source
Performance Standards for the Fabricated and Reclaimed Rubber Segment of The Rubber
Processing Point Source Category", USEPA Publication No.440/1-74/030a, Group I, Phase
II, December 1974.
19. USEPA, "An Investigation of Techniques for Removal of Chromium for Electroplating
Wastes", Publication no. 12010 EIE 13/71, 1971.
345
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THE USE OF HORIZONTAL WELLS IN
REMEDIATING AND CONTAINING
A JET FUEL PLUME -
PRELIMINARY FINDINGS
by Daniel Oakley, Science & Technology, Inc.;
Mark Thacker and Karen Singer, CDM Federal Programs Corporation;
Jack Koelsch. Martin Marietta Energy Systems, Inc.;
and Bill Mabson, Dynamac Corporation
ABSTRACT
A Pilot Study/Demonstration Study (PS/DS) is being performed at Williams Air Force Base in
Chandler, Arizona, to demonstrate the ability of horizontal wells to remediate and contain a jet fuel
plume. The jet fuel plume is floating on the water table at approximately 220 ft below ground
surface. The associated dissolved plume flows east-southeast in the shallow aquifer that is
approximately 25 ft thick.
One horizontal well is installed in an east-west direction with the screen located approximately 15 ft
below the floating jet fuel. This well is parallel to the long axis of the plume. During the PS/DS,
this well will be evaluated for the ability to capture the most contaminated section of the plume.
Based on testing of the first horizontal well, a second horizontal well may be installed in a north-south
direction near the downgradient edge of the dissolved plume. This well will be perpendicular to the
long axis of the plume. During the PS/DS, this well will be evaluated for the ability to act as a
barrier to plume migration.
A short-term pumping test has been performed on the horizontal well. Short- and long-term pumping
tests have been performed on vertical extraction wells also installed at the site. Preliminary findings
of these pump tests are compared and discussed.
1. INTRODUCTION
The U.S. Air Force Air Training Command is conducting a Pilot Study/Demonstration Study (PS/DS)
at Williams Air Force Base in Chandler, Arizona, which is listed on the Environmental Protection
Agency National Priorities List. The purpose of this PS/DS is to evaluate the ability of horizontal vs
vertical extraction wells for the remediation and containment of a jet fuel plume at the liquid fuels
storage area (LFSA). The PS/DS is performed under an interagency agreement between the
Department of Defense and the Department of Energy that is being administered by Martin Marietta
Energy Systems, Inc.'s, Hazardous Waste Remedial Actions Program (HAZWRAP). CDM Federal
Programs Corporation has been contracted by HAZWRAP to conduct the PS/DS.
The LFSA covers approximately 5 acres and has been used since 1942. The fuel storage system was
composed of numerous underground storage tanks and several thousand feet of 4-in.- and 6-in.-diam
delivery pipes. Most of this fuel storage system has been removed. Leaking tanks and fuel lines
346
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have resulted in a JP-4 jet fuel plume in the uppermost aquifer. This plume consists of a free product
plume (650,000-1,400,000 gal) (IT Corporation 1992) and an associated dissolved contaminant plume.
Beneath the site, an unsaturated zone of intermixed clay, silt, sand, and several gravel zones and thin
caliche layers extends to a depth of 220 ft below land surface (bis). These deposits are representative
of channel, floodplain, terrace, and alluvial fan deposition (Laney and Hahn 1986). The shallow
aquifer is approximately 25 ft thick and is composed of intermixed clay, silt, and sand. Underlying
the shallow aquifer is a clay aquitard approximately 20 ft thick. Below the aquitard is a semiconfined
aquifer that is several hundred feet thick and is used as an irrigation and drinking water supply.
Investigations between 1984 and 1992 resulted in the installation of 31 shallow and 5 deep monitoring
wells (Fig. 1). Potentiometric data from the site indicate that groundwater flow in both aquifers is to
me east-southeast. The eastern extent of the aquitard is currently unknown, although it has been
identified in diree downgradient compliance wells more than 1000 ft from the LFSA. Apparent
product thickness measurements from wells within the free product plume vary from <0.1 ft to > 10
ft. Groundwater sampling results indicate a large dissolved contaminant plume in the shallow
unconfmed aquifer associated with die free product plume.
2. PROJECT PURPOSE AND SCOPE
The purpose of die PS/DS is to compare the effectiveness of horizontal and vertical extraction wells
in containing and remediating contaminated groundwater from the shallow unconfined aquifer. Before
contracting installation of the first horizontal weil, a groundwater model was used to help evaluate
potential effectiveness of horizontal wells at this site. The model, which will be discussed in more
detail later, indicated that horizontal wells would be an effective means of capturing die contaminant
plume.
Based on die plume geometry, hydrogeological characteristics, and modeling results, it was
determined mat die optimum placement of the first horizontal well would have an east-west
orientation with a screen 500 ft in length located approximately 15 ft below the floating jet fuel (235
ft bis). This weil, parallel to die long axis of die plume, is the longest and deepest horizontal well
ever installed for environmental cleanup applications. During die PS/DS, this well will be evaluated
for the ability to capture die most contaminated portion of die plume. If testing of mis horizontal well
indicates efficient plume recovery, a second horizontal well with a screen 500 ft in lengdi will be
installed in a north-south orientation near the downgradient edge of the dissolved plume. This weil
will be perpendicular to die long axis of the plume. During the PS/DS, this well will be evaluated for
the ability to act as a barrier to plume migration.
Two vertical extraction wells were installed near die upgradient edge of the free product plume to
compare die efficiency of horizontal and vertical wells at this site . Both a 4-in.- and a lO-in.-diam
extraction well were installed to evaluate the increase in efficiency widi well diameter. Two
additional monitoring wells were installed for use as observation wells during aquifer testing.
Upgradient of the plume, four 4-in.-diam injection wells were installed in the unsaturated zone.
Groundwater will be extracted during long-term tests from the horizontal and vertical extraction wells,
treated in a wastewater treatment plant, and reinjected into the shallow unconfined aquifer. This
347
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00
Approximate Extent SL Surface Location
of Free Product ....
EH Exit Hole
Fuels Wastewater
Treatment System
(FWWTS)
200 10QO JQO 200 300
SCALE IN FEET
5 ppb Benzene
Figure 1. WELL LOCATION MAP.
-------
should prevent dewatering of this relatively thin, low-yielding aquifer and accelerate the rate of
cleanup by creating a groundwater mound upgradient of the plume.
3. PRELIMINARY MODELING
A three-dimensional model (DYNFLOW) using a horizontal finite element grid of 725 nodes and
1344 elements was used to simulate the potential effectiveness of horizontal wells at this site. Based
on previous aquifer test results, a horizontal hydraulic conductivity (KJ of 1 ft/day was used.
Vertical hydraulic conductivity (KJ/Kh was varied between 1/10 and 1/100. Specific yield was
assumed at 0.20. The elevation of the horizontal wells was evaluated at 5 and 15 ft below the
groundwater surface. Pumping rates were varied from 13 to 40 gpm and test duration from 10 to 360
days. Figure 2 illustrates me predicted groundwater surface after 360 days of pumping at 15 gpm
from two horizontal wells wim screens located 15 ft below the groundwater surface. The leading
edge of the contaminant plume is engulfed within the zone of capture. Therefore, the preliminary
results indicated that two horizontal wells should effectively contain the contaminant plume.
4. VERTICAL WELL INSTALLATION
The two vertical extraction wells were installed to a depth of approximately, 250 ft with a mud rotary
drill rig. The saturated zone was cored, and screen slot size was determined based on sieve analysis.
Forty feet of 0.010-in. slotted, wire-wrapped, stainless steel screen was placed to extend 10 ft above
the static water table. A carbon steel riser was installed above the screen to ground surface. The
annuius was backfilled with 20/40-size quartz sand to 3 ft above the screen. A 2-ft-thick bentonite
seal was installed above the sandpack. The annuius was then backfilled to ground surface with
cement bentonite grout. Monitoring well construction was similar except for the use of 0.020-in.
slotted screen and PVC riser material.
The four injection wells were installed to a depth of 200 ft with a mud rotary drill rig. Construction
specifications were 100-180 ft of 0.020-in. slotted, inverted V-wire wrapped, stainless steel screen
with stainless steel riser to the ground surface. The annuius was backfilled in the same manner as the
extraction wells.
5. HORIZONTAL WELL INSTALLATION
The horizontal well was installed using river crossing technology to a depth of 235 ft. Two boreholes
were abandoned because of drilling or installation difficulties before successful installation of the first
horizontal well. The custom-made rig used for installation included a hydrauiically operated, gear-
driven feed frame trailer, a control trailer, and a mud tank/mixer trailer. The gear-driven feed frame
trailer is raised at one end, and the odier end is placed in a mud pit to set the entry angle. For this
well, the entry angle was 20° to the ground surface.
349
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Ul
o
•230-
BUCHANNON ST.
LEGEND
Reinfection Well
f* '\ Approximate Extent
of Free Product
Fuels Wastewaler
Treatment System
(FWWTS)
5 ppb Benzene
-240—Water Level Contour
•HHB Well Screen
SL Surface Location
EH Exit Hole
Figure 2. MODELING OF EXTRACTION AND REINJECTION.
Extraction/Reinjection Rate - 15 GPM/Well
360 Day Water Level Contours
200 100 _JL JOO 200 300
SCALE IN FEET
-------
Figure 3 illustrates the well installation technique. A pilot hole (step i) is drilled at a 20° angle and
becomes horizontal at 860 ft measured length (235 ft true vertical depth). The pilot hole is then
steered horizontally for 500 ft, and the angle is then built to 16° toward an exit location 1250 ft
beyond the end of the horizontal section. The pilot hole is drilled with 6-in.- diam drill string and a
9-in.-diam tricone bit. The drill string is steered using a bent subassembly and a drill bit with one
jet. Increasing the borehole angle up or down, left or right, is achieved by orienting the bent
subassembiy in the desired direction and jetting while advancing the drill string without rotation.
Drilling a straight hole without changing the angle is accomplished by rotating the drill string while
jetting.
A downhole magnetic guidance system, located in the probe directly behind the drill bit, is connected
to the surface by wire line and determines the real-time inclination and azimuth of the bent
subassembly. Based on this information and the pipe length, trigonometry is used to determine the
borehole location. Secondary confirmation of the borehole location is obtained by halting drilling
operations every 30 ft (one joint length) and applying an electrical current to a wire loop on the
surface, thereby creating a magnetic field of known geometry and intensity over the padi of the
borehole. This magnetic field is measured at the probe and modeled. The location of the probe is
then determined relative to the proposed borehole path.
The downhole location equipment is a proven technology for river crossing boreholes, which are
usually no deeper than 100 ft bis. Drilling of the three boreholes during this project showed that the
secondary confirmation tools lost depth accuracy below 150 ft. The secondary confirmation tool
azimuth readings generally remained accurate throughout the three boreholes. The primary downhole
magnetic guidance system remained accurate for depth and azimuth throughout the three boreholes.
A downhole gyroscopic tool was used to confirm the borehole location for the first two boreholes.
This tool confirmed that the boreholes were within 2.5 ft (plus or minus) of the proposed depth.
After the pilot hole is successfully installed, a 16-in.-diam reamer bit is attached to the drill string at
the exit location and pulled back to the entrance location, thereby enlarging the borehole (step 2).
Drill string is shuttled from the entrance to the exit location and added behind the reamer bit so that a
complete drill string remains in the borehole. After completing the first ream, an 18-in.-diam
reamer bit is added at the exit location and pulled back by the same method, further enlarging the
borehole (step 3). After completion of the second ream, the 16-in.-diam reamer bit is again attached
to the drill string at the exit location. Immediately behind the reamer bit is a swivel assembly.
Behind this swivel assembly are the well completion materials. The swivel assembly allows rotation
of the drill string and reamer bit without rotation of the well completion materials. This minimizes
stress on the well completion materials during installation. All well completion materials are welded
together and placed on rollers on the ground surface before installation. The well materials are then
pulled into place from the exit to the entrance location for well completion (steps 4 and 5).
Figure 4 illustrates well construction specifications including 500 ft of prepacked, 0.008-in. slotted,
wire-wrapped, stainless steel screen with 40/60 sandpack. The inside diameter of the screen is 6.0 in.
and the outside diameter is 10.75 in. The prepack sandpack is 1.7 in. thick. Epoxy-coated carbon
steel riser material 11 in. in diameter and 860 ft long is installed from the screen to ground surface.
Well development was accomplished by first attaching a fire hose to the well and flushing water down
the well, out the screen, and up the annulus, exiting at both the entrance and exit locations. The well
was flushed for 6 hours at 150 gpm until returns cleared significantly. The exit borehole was then
351
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Ground Surface
Horizontal
able
1250-ft —
600-1 +— 500-1 -H
Directional drill 9-in. pilot hole
•Boo-t—Jt— soo-fl.
2) 16-in. putt ream
eOO-fl. J- 500-ft. -I1 1250-ft.-
3) 18-in. pull ream
N)
Rfinghead
Borehole
Dri Slam
Ground Surfact
0.220-
Horizontal
-800-fl-
-500-fl-
-izsan.
Pulling well completion materials
into place
Scnen
End Cap •
Ground Surface
Horizontal
-BOO-flr
Abandoned
BordKle
5) Completed horizontal well
Not to Scale
Figure 3. DRILLING AND HORIZONTAL WELL INSTALLATION PROCEDURE.
Williams Air Force Base
-------
Entry
-Cament/grout
seal to surface
Cement/grout—,
seal to surface \
Exit
235 ft.
11-ln. epoxy-eoated
steel riser
Centralized—
submersible /
pump /
Native materials
Miiih i,!• i 111,
•••—••mTTTTTI
IUHHin P i"1' in ''I
V-40.75-IR. OJ}., 6JWn. I.D.
stainless steel
prepack screen
500ft.
Not to Scale
Figure 4. HORIZONTAL WELL CONSTRUCTION DIAGRAM.
plugged and a jetting tool inserted in the screened section of the well. An environmentally safe
spotting fluid designed to break up mudcake on the borehole walls was pumped into the well screen at
three locations. The borehole was then allowed to sit for 24 hours before another high volume flush
was performed. The entrance borehole was then plugged and a pump placed in the well. Pumping
was performed with the pump located in different sections of the well screen until the water became
clear of suspended solids.
6. AQUIFER TESTS
Aquifer tests of the vertical and horizontal wells were performed to provide data for development of a
more realistic interpretation of the aquifer underlying the site.
7. VERTICAL WELL AQUIFER TESTS
Step-drawdown and constant rate 72-hour aquifer tests were performed on the 4-in.- and lO-in.-diam
vertical extraction wells, EX-01 and EX-02. Additionally, EX-02 was pumped for 21 days. Water
levels were recorded using data loggers and transducers placed in monitoring wells MW-30 and
MW-31 and extraction wells EX-01 and EX-02. All wells are fully penetrating and screened in the
same interval.
353
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Before conducting the first aquifer test, background water levels were monitored. Barometric pressure
and precipitation measurements from the Sky Harbor Airport in Phoenix were obtained during the
testing periods to evaluate their effect on water levels. Eight-hour step-drawdown tests initially were
performed on the vertical extraction wells to determine the specific capacity of the wells and to
choose the optimum pumping rate for die long-term tests. Constant rate pumping tests were
performed on the two vertical extraction wells. After completion of each constant rate test, recovery
of the water table was monitored.
8. VERTICAL WELL RESULTS
Vertical extraction well EX-01 was pumped at a constant rate of 3.8 gpm for 72 hours. Well EX-Q1
is 254 ft deep and screened between 212 and 252 ft bis. Before the start of pumping, the static water
level was 215.4 ft bis. Transducers were placed in the pumping well (EX-01) and three observation
wells fMW-31, MW-30, and EX-02) to record drawdowns. Wells MW-31, MW-30, and EX-02 are
27, 102, and 127 ft, respectively, from the pumping well, EX-01.
After 72 hours, a total of 14.6 ft of drawdown was measured in the pumping well. Drawdowns in
the observation wells ranged from 0.61 ft in MW-30 to 0.42 ft in EX-02. In general die data
indicate steep cones of depression surrounding the pumping well because of low transmissivity of the
formation.
Distance drawdown plots indicated the largest drawdown was recorded in observation well MW-30,
more than 100 ft from the pumping well. This suggests an increased hydraulic connection between
EX-01 and MW-30 relative to the other observation wells. This is possible considering the site
stratigraphy of interbedded sands, silts, and clays. Well MW-31 recorded the next largest drawdown
and is widiin 27 ft of the pumping well.
Time vs drawdown plots from the pumping and observation wells resemble delayed gravity drainage
as described in Fetter (1988). The corrected drawdowns in EX-01, MW-31, and MW-30 were used
to determine hydraulic conductivity and specific yield values using the Neuman Method (1975) for
delayed gravity drainage. Horizontal hydraulic conductivities calculated from observation well data
ranged from 9.62 ft/day to 11.73 ft/day. Calculated vertical hydraulic conductivities ranged from.
0.07 ft/day in MW-30 to 0.08 ft/day in MW-31. These correspond to a k/k,, ratio of approximately
1/140. Specific yields (Sy) ranged between 0.023 (MW-30) and 0.286 (MW-31). The time
drawdown plot for MW-30 may not have reached the late curve, resulting in the lower values of Sy
Time drawdown data for EX-01 resulted in a hydraulic conductivity of 3.0 ft/day. Recovery data
from EX-01 was used to calculate a hydraulic conductivity of 2.58 ft/day.
Extraction well EX-02 was pumped for 72 hours at approximately 2 gpm. Drawdown in the
observation wells increased until 1100 minutes into the test. At this time, the drawdown declined
steadily until the last day of the 3-day test when it began to rise in a curve similar to the initial
drawdown. Total rainfall for the month before this test was three times the monthly average. The
sudden drop in drawdown may be partially caused by delayed gravity drainage from low permeability
clays. Because of the later anomalous data, drawdown data from MW-30 for the first 1000 minutes
of the test was used to calculate a hydraulic conductivity of 1.8 ft/day.
354
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Sustained pumping rates from the two vertical extraction wells varied considerably. Also distance
drawdown plots did not decrease linearly with increased distance from the pumping well. These
findings indicate heterogeneous, nonisotropic conditions. Increasing well diameter did not increase
recovery. Recovery rates are a function of formation properties and well efficiency.
9. HORIZONTAL WELL AQUIFER TEST
A 3-day constant rate aquifer test was performed on the horizontal well. The pump was placed in the
middle of the screened section, and a transducer was installed inside a drop pipe placed at the
beginning of the horizontal section. Transducers were installed in monitoring wells LI-06, W-01, W-
03, W-05, and W-08 surrounding the horizontal screened section.
During the test, hand water level and product-water interface measurements were taken to confirm
transducer readings and to determine the effect that pumping has on the product-water interface.
10. HORIZONTAL WELL RESULTS
The pumping test on the horizontal well consisted of pumping the well at 9.8 gpm for 3 days. Wells
within 30 ft of the horizontal well recorded drawdowns of less than 0.40 ft indicating a steep cone of
depression similar to that observed in the vertical well aquifer tests. During the test, product
thicknesses rose steadily in the observation wells within the free product plume. The water table
decline in the cone of influence was minimal. The apparent product thickening is likely the result of
removing the skimming system from these wells 48 hours before initiating the test.
The value of hydraulic conductivity from the horizontal well test data was calculated using the
following analytical equation for flow to a trench (Powers 1981).
_Q = KfH2 - h2
2X 2880 L
where:
Q = discharge (gpm)
X = length of trench (screen) (ft)
K — hydraulic conductivity (gpd/ft2)
H = saturated thickness at distance L from trench (ft)
h = saturated thickness above screen at end pumping (ft)
L = distance between trench and point where H
is measured (ft).
355
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Calculated hydraulic conductivities ranged from 0.14 to 0.33 ft/day. These values are much lower
than those calculated from the vertical well aquifer test data. This is not unexpected because of the
adverse impact to the formation from the three attempts at well installation. Upon completion of an
on-site treatment system, the well will be developed further and pumped to obtain additional data.
11. FUTURE MODELING EFFORTS
Currently the finite element numerical model (DYNFLOW) developed by CDM Federal is being
adapted to include site geologic conditions as well as calculated hydraulic properties at the site.
Results of aquifer tests from the horizontal well will be used for transient calibration of the model.
This will enhance the model's capability to predict aquifer response to pumping in the horizontal well.
12. SUMMARY AND CONCLUSIONS
The PS/DS being performed to evaluate the ability of horizontal vs vertical extraction wells to
remediate and contain a JP-4 plume will require additional data before definitive conclusions can be
reached. Four-in.- and lO-in.-diam vertical extraction wells and a 6-in.-diam horizontal extraction
well have been successfully installed. Only preliminary aquifer testing of the horizontal well has been
performed.
Aquifer test results from vertical extraction wells show low transmissivity and vertical hydraulic
conductivity and a very steep cone of depression. Therefore, a tight vertical well spacing (25-50 ft)
would be required to remediate the site with vertical wells. These tests also indicate that increasing
well diameter does not increase the recovery rate in this heterogeneous formation.
A short-term aquifer test performed on the horizontal well also shows a very steep cone of
depression. Based on the initial results, a horizontal well may perform more effectively as a barrier
than for plume recovery at this site. After further testing, a decision will be made as to whether a
second horizontal well will be installed at this site.
Future testing of the horizontal well will include pumping at different locations in the horizontal well
screen, long-term (30 day) and short-term tests, low and high pumping rate tests, an evaluation of
whether product recovery from the skimming pumps is increased during water table depression, and
pumping from two pumps simultaneously in the horizontal well.
356
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REFERENCES
Fetter. C. W. 1988. Applied Hydro geology, Second Edition. Merrill Publishing Company,
Columbus, Ohio.
IT Corporation 1992. U.S. Air Force Remedial Investigation/Feasibility Study, Williams Air Force
Base, Arizona, Remedial Investigation Report, Liquid Fuels Storage Area - Operable Unit 2
Vol. 1.
Laney, R. L. and Hahn, M.E. 1986. "Hydrogeoiogy of the Eastern Part of the Salt River Valley
Area, Maricopa and Pinard Counties, Arizona," U.S. Geological Survey, Water-Resources
Investigations Report 86-4147.
Neuman, S. P. 1975. "Analysis of Pumping Test Data From Anisotropic Unconfmed Aquifers
Considering Delayed Gravity Response," Water Resources Research, Vol. 11, No. 2.
Powers, J.P. 1981. Construction Dewatering, a Guide to Theory and Practice, John Wiley & Sons.
357
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EVALUATION OF THERMAL E)CrRACTION TECHNOLOGIES FOR TREATMENT OF
SOILS CONTAMINATED WITH COAL TARS AND WOOD PRESERVATIVES
AT THE PACIFIC PLACE SITE, VANCOUVER, B.C.
Sandra Whiting, Gregory Helland, John Kinsella
SCS Engineers, Bellevue, Washington
358
-------
INTRODUCTION
The British Columbia Ministry of Environment, in cooperation with Environment Canada's
Demonstration of Site Remediation Technologies (DESRT) Program, conducted treatability studies of
several treatment technologies to evaluate their effectiveness for the treatment of soil from a
contaminated site.
The site is a 185 acre area of industrial land located in Vancouver, B.C. Historically, a wide variety
of industrial activities operated on the site, including two manufactured gas plants, sawmills, boat
building, metal plating, wood preservation, carpet cleaning, railway yards, and fuel storage. In
particular, coal tars and metal oxide wastes from the coal gasification plants and wood preservatives
were mixed with fill material. Contaminants detected at elevated concentrations on the site included
polycyclic aromatic hydrocarbons (PAHs), cyanide, lead, sulfur, total petroleum (extractable)
hydrocarbons, and chlorophenols.
The technologies evaluated included incineration, thermal extraction, bioremediation, and
stabilization/solidification. This paper focuses on the testing of two innovative thermal extraction
technologies: the Chemical Waste Management XTRAX process; and the UMATAC Industrial
Processes AOSTRA Taciuk Processor. This paper includes a brief description of each technology,
procedures utilized in each study, results, and estimated costs for full-scale treatment.
CHARACTERISTICS OF SOILS TESTED
Soil samples were collected from the site by excavating pits to the desired depths; the targeted soils
were then mixed in the excavation using the bucket of the excavator. After mixing, samples were
coarsely screened and placed into shipping containers. All samples were shipped to vendors in
accordance with the Canadian Transportation of Dangerous Goods Regulations and the U.S.
Department of Transportation Regulations.
Four different sample types, with varying concentrations of PAHs, chlorophenols, oil and grease, and
metals, were provided for testing in the thermal extraction systems. As would be expected from
such a site, the fill was heterogenous and contaminant concentrations exhibited a wide variability,
even between split samples. In general, all the soil samples were poorly sorted (well graded) and
were characterized as consisting primarily of fine to coarse sand with approximately 17 to 34% silt
and clay. Samples also contained debris such as brick fragments, metal fragments, and wood
chunks. Sample moisture content ranged from 10 to 45% and averaged 25%. The pH of each
sample was near neutral (6.9 to 7.2) except for Sample 1, which had a pH ranging from 4.2 to 5.0.
The chemical characteristics of each of the four samples are summarized below.
Sample 1. This sample location is characterized by the presence of coal tars; the average
concentration of total PAHs in Sample 1 was 3,375 mg/kg. Oil and grease concentrations ranged
from 29,000 to 200,000 mg/kg with average concentrations of 112.0OO mg/kg. Total cyanide
concentrations in Sample 1 were between 2,900 and 5,000 mg/kg. Sample 1 also was notably high
in total sulfur (ranging from 1 to 17 percent).
Sample 2. Total PAHs in this sample ranged from 42 to 348 mg/kg (averaging 117 mg/kg). Oil and
grease concentrations ranged from 4,200 to 15,600 mg/kg. Lead concentrations were between 116
and 5,600 mg/kg in this sample. Zinc was also high, averaging 2,347 mg/kg.
359
-------
Samp/e 3. This sample was collected from an area historically used as a dip tank for wood treating.
Pentachlorophenol concentrations ranged from 9 to 309 mg/kg (averaging 136 mg/kg) and
tetrachlorophenol ranged from 125 to 500 mg/kg (averaging 242 mg/kg). PAHs were also detected
in this sample, averaging 260 mg/kg total PAHs. Oil and grease ranged from 8,300 to 23,200
mg/kg.
Samp/o 4. Sample 4 was characterized by high concentrations of lead, ranging from 8,000 to
12,500 mg/kg. Total PAHs averaged 151 mg/kg; oil and grease concentrations averaged 700
mg/kg.
TREATABILJTY STUDY PROCESS
The vendors were required to perform detailed chemical and physical analyses of the soil samples
using specified analytical protocols, prior to treatment and at the end of the treatment period. In
addition, detailed analysis of treatment by-products or residuals was also required.
The major objectives of the treatability studies were to:
Determine or validate technology effectiveness.
Develop pricing data for full-scale operation.
Evaluate the likelihood of delisting treated waste under B.C. procedures.
Demonstrate compliance with emissions and effluent standards.
Provide information potentially useful for other contaminated sites.
Cleanup goals were established for the treatability study program in order to evaluate technology
performance. The "British Columbia Standards for Managing Contamination at the Pacific Place
Site', developed by the British Columbia Ministry of Environment, formed the basis for the target
clean-up levels for organic contaminants. The clean-up goals are included in Tables 1 and 2.
A brief description of each thermal extraction technology, the study procedures used in testing, the
testing results and estimated costs are discussed in the following sections.
X*TRAX
Technology Description
The X*TRAX system, developed by Chemical Waste Management, Inc., is a low temperature thermal
separation process that vaporizes or steam strips organic compounds from soils or sludges. It
consists of an externally fired rotary dryer and gas treatment system. A simplified flow diagram of
the X*TRAX system is provided in Figure 1.
Soils or sludges are fed into a rotary dryer and heated. Treated solid residues exit the dryer and are
collected in a hopper. Nitrogen is used as a carrier gas for the volatilized organics which are
transported from the rotary dryer to a gas treatment system.
The gas treatment system includes a spray tower/scrubber, primary and secondary shell-and-tube
heat exchangers for condensing the gases. In the full-scale X*TRAX system, most of the nitrogen
gas is recycled, except for about 10 percent that is vented to the atmosphere. The bench-scale
system is equipped with two activated carbon filters for treating residual organics in the gas stream.
360
-------
Liquids and particulates (and less volatile organic compounds) from the spray tower are passed
through a gravity phase separator and are then filtered to separate out solids. Condensed liquids
from the heat exchangers are composited, filtered, and phase separated for further treatment as
necessary.
Review of the flow diagram indicates that the X*TRAX system produces several treatment residuals:
Treated solids from the dryer
Phase separator water (this is continuously recycled to the spray tower)
Phase separator filtrate (particulates and some organics)
Phase separator oil
Filtrate from condensate
Condensed water
Condensed oil (not always produced in lab-scale tests)
Emissions
The full-scale X*TRAX system is a transportable unit capable of treating up to 125 tons per day of
soil with a moisture content of 20%. CWM also operates a pilot-scale unit that is mobile and can
treat about 5 tons per day of material containing 30% moisture.
Testing Program
Bench-scale treatability testing was conducted using a laboratory-scale X*TRAX unit which uses the
same components as the full-scale X*TRAX system. Samples 1, 2, and 3 were individually tested at
two operating temperatures: 482°C and 371 °C. In all cases, residence time was 85 minutes Prior
to processing, the samples were screened through a 1/4 inch sieve and then homogenized The
feed was sampled once each hour, beginning and ending at steady state conditions. The feed
samples were composited for each temperature condition and later submitted for laboratory
analyses. An average of about 7 kilograms of each soil sample was fed to the system. Feed rate
ranged from 8 to 13 grams per minute, depending on the sample type.
Treated solids and condensates were collected and weighed every 15 minutes. Solids were
composited for each steady state condition and then were subsampled for analytical testing The
condensates and phase separator liquid were filtered through 25 micron filter paper The filtered
condensate was poured into a separatory funnel from which samples for analysis were taken The
filter cakes and phase separator water products were subjected to chemical and physical analyses.
Because of the small scale, no organic liquid phase products were generated in these studies nor
were emissions collected and analyzed.
Results
The analytical results indicate that the X*TRAX process was effective at removing organic
compounds from contaminated soils and meeting the treatment goals for the treatability study
Table 1 provides a summary of results for the 482°C operating condition.
In Sample 1, the highly contaminated sample, total PAHs (16) were reduced by 99.93 percent at the
482°C operating condition. The concentrations of PAHs (as well as other organic constituents) in
the treated soil were well below the established treatment goals. Similar PAH and other organic
compound removal efficiencies were achieved in Samples 2 and 3.
Pentachlorophenol was reduced by an average of approximately 98 percent, and
2,3,4,6-tetrachlorophenol by an average of approximately 92 percent for all three samples tested.
361
-------
Figure 1. X*TRAX Flow Diagram
ON
to
LIQUID NITROGEN
GAS
HEATER
DRYER
r
TREATED
SOLIDS
HOPPER
GAS
GRAVITY
PHASE
SEPARATOR
T
LIQUID
SOLIDS
FEED
GAS
SPRAY
TOWER/
SCRUBBER
RECYCLED NITROGEN
FULL/PILOT-SCALE
1
CONDENSER
(PRIMARY)
GAS
LIQUID
CONDENSATE
L_
TO
ATMOSPHERE
CONDENSER
I(SECONDARY)
GAS
•M-
LIQUID!
M
CONDENSATE
I
CARBON
FILTER
(LAB-SCALE
ONLY)
FILTRATION
\
WATER OIL FILTER CAKE
T
FILTRATION
Source:
Modified from "Pacific Place Project Treatability Technical Study for British Columbia Hazardous Waste Management Corporation", Chemical
Waste Management of Canada, Inc.
-------
Concentrations of chlorophenols in some of the treated soils appeared to be slightly above the
treatment goals.
The vendor reported that concentrations of dioxins and furans in the Sample 1 feed soil (3.7 ppt
TCDD equivalency) decreased after processing through the X*TRAX system (to 1.6 ppt TCDD
equivalency).
Total metals concentrations in the samples did not change significantly as a result of the X*TRAX
treatment process, nor did the solubility of the metals appear to be affected by treatment, based on
extraction testing. Total cyanide in the treated soils from Sample 1 was reduced from 2,500 mg/kg
to 6 mg/kg in the lower temperature run and to less than 0.5 mg/kg in the 482°C run.
Organics concentrations in the condensed water and phase separator water produced during the
treatability study were generally very low or insignificant except for oil and grease and total
phenolics. Oil and grease concentrations ranged from less than 5 to 24 ppm. Total phenolics were
detected at high levels in both condensed and phase separator water (54 and 58 ppm, respectively)
from Sample 3 soils and in condensed water from Sample 1 soils (5.51 ppm). These concentrations
exceed the B.C. effluent standard for phenols.
There were insufficient products to allow for the analysis of liquid-phase organics. Analysis of
emissions during the treatability study was not performed due to the small scale of the equipment.
Examination of the analytical testing performed on treatment residuals from this study shows that a
significant proportion of the PAHs from all sample types and chlorophenols in Sample Type 3 were
removed in the spray tower and were deposited on the phase separator filter cake. A small amount
of the total PAHs and chlorophenols were also removed from the piping between the dryer exit and
the spray tower ("carryover holdup"). Some of the cyanide was also removed on the phase
separator filter cake and from the piping between the rotary dryer and the spray tower.
Estimated Treatment Costs
The vendor estimated a unit cost for soils treatment and disposal of condensed liquids and filtrates
at about $600(US) per ton. The cost assumed treatment of about 27,000 tons of soil, and included
mobilization, labor, health and safety, sampling and analysis, and ambient air monitoring.
Discussion
Based on the data provided in the treatability study report, the X*TRAX process appears to be an
effective technology for removing organic contaminants from the tested soils. However, several
treatment residuals are produced that require proper management/disposal (i.e., filtrates, condensed
oil, condensed water, phase separation water).
During full-scale operation of the X*TRAX, condensed water and phase separator water produced
during the treatment are typically applied to the treated soil to control dusting. As noted above, the
concentrations of some organic contaminants in the two wastewater streams were of concern,
making the use of the water for dust control a questionable practice. However, CWM reports that in
full-scale treatment the water is tested first to ensure that the quality of the water is acceptable (for
disposal of the treated soil) before it is applied to the treated soil.
The treatability study could not provide data on condensed organic-phase liquids, and full-scale data
pertaining to this waste stream were not available at the time of the testing program. However, if
free-phase organic liquids were produced during full-scale operation, it is likely that they would
require incineration at an approved hazardous waste incinerator.
363
-------
TABLE 1. Selected Organic Contaminant Concentrations, X*TRAX TreatabllHy Study
Contaminant
PAHs
Benzo(a)anthracene
Chrysene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(g,h.i)perylene
Pyrene
Benzo(a)pyrene
lndeno(1 ,2,3-cd)pyrene
Acenaphthene
Acenapthylene
Anthracene
Fluoranthene
Fluorene
Napthalene
Phenanthrene
Total PAHs
Chlorophenols
2,4,6-Trfchlorophenol
2.4,5-Trichlorophenol
2,3,4,6-Tetrachlorophenol
PsntachloroDhenol
Sample 1
Run Feed
(ppm)
<0.014
65
60
27
190
220
400
61
<0.005
45
100
530
110
1,300
320
3,428
<0.42
<0.66
<0.66
<1 8
482 'C
Treated Soil
(ppm)
0.18
0.20
<0.001
0.050
<0.0047
0.35
<0.010
0.033
<0.005
<0.008
0.057
0.68
<0.0006
0.41
0.29
2.25
<0.42
<0.66
<0.66
<1.8
Sompte Type 2
Run Feed
(ppm)
3.2
3.5
4.3
5.1
<0.0047
4.4
9.5
3.7
<0.005
<0.005
8.8
6.3
1.8
<0.005
3.5
54.1
<0.07
1.6
2.4
9.4
462* C
Treated
Soil (ppm)
<0.014
<0.001
<0.001
<0.0004
<0.0047
<0.0025
<0.010
<0.001
<0.005
<0.008
<0.0007
<0.0007
<0.0006
<0.005
<0.005
0
<0.07
<0.11
0.58
<0.30
Sampto Typ« 3
Run Feed
(ppm)
12
11.0
9.1
6.8
8.9
36.0
18.0
6.8
<0.008
<0.008
5.3
43.0
4.3
<0.005
27.0
192.6
<0.07
<0.11
<0.30
<0.035
482' C
Treated
Soil (ppm)
<0.001
<0.001
<0.004
<0.0047
<0.0025
<0.010
<0.001
<0.005
<0.008
<0.0007
<0.0007
<0.0006
<0.005
0.18
0.18
<0.07
<0.11
<0.11
<0.3
TreatmBntGoate
(Pacific Place Level
B Standard*
(ppm)
1
1
1
1
1
10
1
1
10
10
10
10
10
5
5
20
0.5
0.5
0.5
0.5
-------
AOSTRA TACIUK PROCESSOR
Technology Description
The AOSTRA Taciuk Processor (ATP) is owned and operated by UMATAC Industrial Processes in
Calgary, Alberta (the technology is also known as the SoilTech ATP Plant in the U.S.). The ATP is a
thermal extraction technology that separates organics from solids by pyrolysis and distillation. A
flow diagram of the ATP is provided in Figure 2. For the treatability study testing, UMATAC was a
subcontractor to Newalta Corporation of Calgary.
The processor consists of a rotary kiln with a preheat zone, operating at about 260°C; a reaction
zone, operating at between 317°C and 649°C; and a combustion zone, operating at 538°C to 815°C.
Water vapor and the more volatile organics are extracted in the preheat zone. Oils and heavier
organics are removed in the reaction zone. Both the preheat and the reaction zones are maintained
in anaerobic conditions to prevent oxidation of the organics. The combustion zone bums coke from
thermal cracking that forms on the solids in the reaction zone. Oxygen is added to the system in
the combustion zone.
The flue gas from the combustion zone is passed through a baghouse and a wet scrubber. Carbon
absorption is sometimes added for final gas scrubbing in full-scale treatment. Treated solids are
discharged from the kiln as tailings. The steam and organics produced in the preheat zone and the
organics separated out in the reaction zone are withdrawn under vacuum and are condensed in
separate vapor trains. The condensed water generally requires treatment before disposal. The oily
waste must either be incinerated or used as fuel for the processor.
As can be determined from examination of the process flow diagram, this treatment process
produces several treatment by-products:
• Preheat Zone
Vapor stream: water, oil, gas (recycled to combustion unit)
Solids stream: heated, dried solids (to reaction zone)
• Reaction Zone
Vapor stream: cyclone solids, bottom oils (removed at 150°C - 210°C),
heavy oils (removed at 100°C - 150°C), light oils (removed in heat
exchanger), sour water, off gases (flared or recycled to combustion zone)
Solids stream: coked solids (to combustion zone)
• Combustion Zone
Flue gas stream: cyclone fines, baghouse fines, scrubber water, scrubber
solids, cleaned gas
Solids stream: treated tailings
365
-------
Oi
o\
Figure 2. Aostra Taciuk Process (ATP) Flow Diagram
-n STACK
WATER
OIL FUEL
FLUE GAS
TREATMENT
FEED
t
VAPOR
TREATMENT
PREHEAT
VAPOR
ATP
PROCESSOR
VENT
GAS
OFF GAS
OIL
VAPOR
SOUR
WATER
T
WATER
OIL
RECOVERY
PRODUCT OIL
TAILINGS
Source: "Treatability Study Report, Pacific Place Soils Remediation Project", Newalta Corporation, June 30,1992.
-------
Testing Program
Both bench- and pilot-scale studies were conducted using the ATP. In addition, a bench-scale
wastewater treatment study was performed to evaluate the effectiveness of a combination of
standard treatment technologies for treating preheat water and sour water. Only the pilot-scale
study is presented here.
Based on the success of the batch-scale testing program, pilot-scale testing in UMATAC's 5 tonne
per hour prototype unit was undertaken. A total of four tests were performed using the 5 tonne per
hour ATP. Samples 1 and 3 were processed separately and a blend of Samples 1, 2, and
4 and a blend of Samples 2 and 4 were also tested. Because of the high sulfur content in Sample 1
and the concern that the sulfur dioxide emissions would be exceeded, UMATAC added sand in a
four-to-one ratio to the sample material before processing. The vendor also added sand to the third
and fourth test runs to reduce moisture content.
Each test lasted between 3.4 and 4.4 hours; feed rates ranged from 2.7 to 4.1 tonnes per hour,
depending on the sample type. Exit temperatures in the reaction zone averaged 526°C. Exit
temperatures in the combustion zone averaged 648°C.
During each test run, samples of the feed and samples of the treated tailings (treated soils,
baghouse ash, and cyclone ash) were collected every 30 minutes. Composite samples of each of
these were submitted for analytical testing. Condensates, both water samples and oil samples, were
also collected every 30 minutes and analyzed from each run.
Monitoring of stack emissions was also performed during three test runs to demonstrate compliance
with emissions standards and for calculating destruction and removal efficiencies (ORE) and mass
balances.
Results
Comparisons of the concentrations of selected organic compounds in the feed material and the
treated soils and ash are provided in Table 2.
In general, the ATP achieved nearly 100 percent removal of organic contaminants from the soil
samples. The concentrations of PAHs in the tailings were all less than detection limits (practical
quantitation limits of 0.33 - 0.53 ppm). It should be noted that concentrations of organics in the feed
were low due to dilution from the addition of sand before processing. For example, after dilution
with sand, the concentration of total PAHs in the Sample 1 run averaged about 46 mg/kg. In the run
combining Sample Types 1, 2, and 4, total PAH concentrations averaged 309 mg/kg. These
concentrations are considerably lower than those found in undiluted soil samples.
Analyses of dioxins and furans were performed for the second run (Sample 3 soils). Concentrations
in the feed, treated soils, and ash streams were all less than 1 ppm. The data provided by the
vendor is suspect, however, due to poor surrogate recoveries reported by the vendor's laboratory.
Useful information about reduction of chlorophenolic compounds was not generated in this testing
program because the concentrations of chlorophenols in the soils received by UMATAC were
non-detectable (6.6 ppm detection limit).
Some volatile organic compounds were detected at high levels (as high as 300 ppm) in baghouse
ash, most notably toluene and xylene. No explanation of these levels was offered by the vendor.
Cyanide was reduced to less than detection limits in the treated soils containing soil from Sample 1.
Generally, low concentrations of cyanide were detected in cyclone dust and baghouse ash.
367
-------
TABLE 2. Selected Organic Contaminant Concentrations, ATP Treatablllty Study
Contaminant
TEH"'
Oil & Grease
Phenols
Total
Chlorophenols1'1
Dloxlns/Furans'3'
Total PAHs m
BTEX B
.
Ftttd
Soil
(ppm)
145
118
<0.01
ND
NT
46.2
ND
Sampt
Treated
. Soil
(PPm) .
ND
26
<0.01
ND
NT
ND
ND
• 1 +Sand
Cycfon*
Duct
(PPm)
ND
22
<0.01
ND
NT
<
ND
BaghouM
Ash
(ppm)
ND
13
0.53
ND
NT
3.3
ND
Sampled
Feed
Sol!
(ppm)
ND
1180
0.13
ND
0.566
2.17
ND
Treated
Soil
(ppm)
ND
21
0.01
<
0.005
ND
ND
Cyclone
Duct
(PPm)
ND
65
0.02
ND
0.553
<
30
BaghouM
A*h
(ppm)
ND
74
0.05
ND
. 0.596
16.5
133
Sample 1, 2, 4 + Sand
F««d
Soft
(PPm)
ND
159
0.05
ND
NT
309.2
<
Treated
8ofl
(ppm)
ND
<5
<0.01
ND
NT
<
ND
Cyctott*
Duct
(PPm)
ND
7
<0.01
ND
NT
<
ND
Bftghout*
Ach
(PPm)
ND
9
<0.01
ND
NT
3.2
130
Treatment Goalt
PucWIcPlac* :
Lov.lB
Standards (ppm)
150
1000
1.0
1.0
NA
20
5.0, 30. 50. 50
Notes: (1) Total Extractable Hydrocarbons (Modified EPA Method 8015), average of duplicate columns. Detection limit In ash streams ranged from 9 to 48 ppm.
(2) Detection limit for pentachlorophenol in treated soils and ash was 1.65 ppm.
(3) Data suspect due to poor surrogate recoveries.
(4) Detection limits for PAHs ranged from 0.33 to 0.462 mg/kg.
(5) Detection limits for BTEX ranged from 20 to 70 mg/kg.
< = Below detection limit
NT = not tested
ND « not detected
Data from: Treatabllity Study Report, Pacific Race Soils Remediation Project," Newalta Corporation, June 30, 1992.
o\
GO
-------
In general, the concentrations of metals were reduced somewhat in the treated soils from what was
reported in the feed, and were higher in the cyclone dust and baghouse ash (particularly arsenic,
copper, lead, tin, and zinc).
The testing program produced about 2.5 tons of oil (1.6 tons of which was from make-up oil for
the hydrocarbon vapor stripper). In general, the oils contained very low levels of inorganics (except
for calcium and sulfur) and low levels of benzene, toluene, ethylbenzene, and xylene (BTEX). The
vendor did not analyze the oils for PAHs or chlorophenols. However, data from the third party
laboratory analyses of the oils, indicated significant concentrations of PAHs in the oils, as would be
expected. Dioxins and furans were also present in significant concentrations (ranging from 0.5 to
130 ppb TCDD toxicrty equivalence) in the bottoms oil from processing Samples 1 and 3 (oil from
the blended run was not analyzed for dioxins or furans). This is based on data from the third party
laboratory. The data from the vendor's laboratory, which also reported high levels of TCDD, are
suspect due to poor surrogate recoveries.
Stack Emissions
During the testing programs, sulfur dioxide limits were exceeded in both tests using Sample 1
material. This, according to UMATAC, was due to the scrubber on the prototype equipment which
can only achieve 50 to 60 percent sulfur dioxide removal.
Particulate limits were exceeded in the second and third test runs (emissions were not monitored in
the fourth test). According to the vendor, this was due to damaged bags in the baghouse that were
not discovered until testing was completed.
Total oxides of nitrogen exceeded the emissions criteria for NO2 in one test run. Since NO2 was not
directly measured, the vendor has stated that it is possible that the NO2 limit was not exceeded.
Carbon monoxide limits were also exceeded. This was explained by the vendor as attributable to
low combustion efficiencies attained during the testing program.
All metals discharges were well below emissions standards. Dioxins and furans were not measured
in emissions samples as planned, because of insufficient sample volume.
The vendor calculated DREs for PAHs using both the B.C. Special Waste Regulation method, and
Alberta Environment's method (which takes into account more of the waste streams). Using the B.C
method for calculation, the vendor reported DREs ranging from 98.41 to 100.00%. DREs of 99.99%
were not achieved for anthracene, fluoranthene, naphthalene, phenanthrene, and pyrene in one or
more test runs.
In general, all of the water products from the processor (preheat, sour, and scrubber water) were
found to be contaminated with various compounds that would require treatment before discharge.
Contaminants present in significant concentrations in one or more of the water samples included oil
and grease, phenols, ammonia, hexavalent chromium, aluminum, lead, manganese, and cyanide.
Naphthalenes were detected in the sour water and preheat water in the parts per billion range. The
scrubber water also proved to contain several contaminants in excess of effluent limits including oil
and grease, aluminum, arsenic, zinc, manganese, total suspended solids, cyanide, and ammonia.
Estimated Treatment Costs
The vendor estimated a unit cost for soils treatment and disposal of condensed liquids and filtrates
at about $200 (US) per ton. The cost assumed treatment of about 27,000 tons of soil, and included
mobilization and demobilization, materials preparation, labor, health and safety, sampling and
analysis, quality assurance/quality control, site preparation, and closure.
369
-------
Discussion
In general, the ATP demonstrated that it was effective at removing organic compounds and cyanide
from the contaminated soils and at meeting the treatability study goals. However, it is not certain
how the pilot-scale processor would have performed had the feed soils not been diluted with sand
and the concentrations of contaminants been higher in the feed.
Emissions standards for metals were met in the study. However, meeting stack emissions for
conventional parameters (SO2, CO, NO2, and particulates) proved problematic for the ATP in this
treatability study. The vendor has concluded that this is due to the use of old equipment that was
not properly functioning. It is expected that some of these problems could be corrected by
improvements in the system (for example, by using properly functioning baghouse filters and a more
efficient scrubber). However, sulfur levels in Sample 1, if they are as high as those found in the
study soils, may require dilution of the soils and/or reduced throughput to meet SO2 emissions
standards, thus increasing treatment costs. Carbon monoxide emissions are indicative of poor
combustion efficiency. The vendor has indicated that CO emissions could be controlled by adding
an afterburner to the unit. However, it is uncertain whether such a modification will be effective, and
it may increase treatment costs.
ORE calculations were based on measurements of PAHs in the soils and the stack emissions. Due
to the variability of contaminant concentrations in the feed soils, the DREs may be somewhat
uncertain. However, the vendor's ORE calculations show that the ORE performance standard of
99.99% was not met for several of the PAH compounds. This may be partly due to the low
concentrations of PAHs in the feed, which make it more difficult to meet DREs.
Based on data from both the vendor's laboratory and the third party laboratory analyses of oils,
significant concentrations of dioxins and furans were found in the oils. Since only very low levels of
dioxins and furans were detected in feed samples (from this and other studies), this may mean that
the ATP is creating dioxins. However, a mass balance has not been calculated to verify this
hypothesis. No information was obtained for evaluating the concentrations of these compounds in
stack emissions.
SUMMARY AND CONCLUSIONS
Bench-scale testing of the Chemical Waste Management XTRAX process and the AOSTRA Taciuk
Processor were performed using soils contaminated with PAHs, chlorophenols, lead, cyanide, and
varying levels of oil and grease. Pilot-scale studies were also performed using the ATP. Based on
the results of the treatability studies, both of .these technologies were effective at removing organic
contaminants from the treatability study soils. Organics in the treated soils ranged from
non-detectable levels to the low parts per billion range and were virtually all less than the treatment
goals.
Stack emissions in the ATP were acceptable for metals but were unacceptable for several
constituents (SO2, CO, NO2, and particulates). The use of equipment in poor repair, limited the
extent to which the emissions results from the testing program could be evaluated and used to
predict performance in full-scale operation.
Emissions in the X*TRAX system were not measured in the study, due to the small quantity of soils
processed. Therefore, additional information from full- or pilot-scale operation of the unit would be
needed to assess compliance with any applicable emissions standards.
370
-------
Of concern in thermal extraction systems is the potential for the production of dioxins and furans
when precursors (particularly chlorophenols) are present. In the ATP test results, concentrations of
these compounds in feed soils and treated soils and ash were insignificant. However, significant
concentrations of dioxins and furans were observed in the condensed oils. In the X*TRAX system,
dioxin and furan concentrations in the feed and treated soil were insignificant and well below
regulatory levels. No dioxin testing was performed on the condensate phases or the off-gases
because these treatment residuals were not produced in sufficient quantities for analytical testing.
Therefore, the question of whether dioxin and furan generation may occur in the X*TRAX system
was not answered in this treatabiiity study.
In conclusion, based on the results of these treatabiiity studies, both the X*TRAX and the ATP
systems appear promising for the treatment of soils contaminated with manufactured gas plant
wastes and wood preservatives. However, additional research or data on full-scale operation of
these systems is needed to address the potential production of dioxins and furans, before either
technology is selected for treatment of soils containing precursors.
371
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CF Systems
Solvent Extraction Technology
For Site Remediation
A Post "Site Demonstration Update"
372
-------
CF SYSTEMS' SOLVENT EXTRACTION TECHNOLOGY
FOR SITE REMEDIATION
A POST "SITE DEMONSTRATION UPDATE"
INTRODUCTION
In September 1988, CF Systems' Solvent
Extraction Technology, on a pilot-scale,
was tested and evaluated under EPA's
Superfund Innovative Technology Evalua-
tion (SITE) Program. The final Applica-
tions Analysis Report (EPA/540/A5-90/002)
was issued in August 1990. This current
paper contains a synopsis of that demon-
stration, an update on recent develop-
ments of the technology, and a review of
the commercial scale application of the
technology.
CF Systems' proprietary Solvent Extrac-
tion Technology uses a liquefied gas, such
as propane, butane or carbon dioxide, as
the solvent to extract organics from solids,
sludges and wastewaters. The solvent,
containing extracted organics, is separated
from the treated product and the solvent
is recovered by distillation in the Solvent
Recovery System, condensed and recycled
to the extraction system. The extracted
organics are discharged from the system
and typically sent either to a disposal or
recycling facility.
The unique physical properties of a lique-
fied gas, such as low viscosity, density
and surface tension, result in a solvent
which has a significantly higher rate of
extraction in comparison to conventional
solvents. Additionally, these enhanced
physical properties accelerate the rate of
settling of the soil/solvent mixture follow-
ing extraction which broadens die applica-
bility of the process to include the treat-
ment of fine days and silty sediments.
Due to high volatility, liquefied gas sol-
vents are easily and economically recov-
ered from die treated waste matrix by
distillation. This minimizes the potential
for solvent residues in the treated soils
and aqueous streams as well as in the
extracted organics.
Materials that can be successfully and
economically extracted include:
• Petroleum-derived hydrocarbons
• Chlorinated hydrocarbons, including
PCBs, dioxins, and pesticides
• Phenols, alcohols, and organic acids
Areas of applications of this Technology
include:
• Remediation of contaminated sludges,
soils, sediment, and fill at Superfund,
production and disposal sites thus:
- eliminating the need for off-site
disposal
- meeting mandated clean-up
standards
- recovering or separating organ-
ics for recycle or disposal
•- Integration with refining, petrochemi-
cal, and industrial processes to:
- minimize or eliminate hazardous
waste production
- minimize treatment costs
- recover product or by-product for
recycle or resale
• Removal of organic contaminants from
wastewater streams to:
- meet regulatory standards for waste-
water discharge
- recover product for recycle
- minimize treatment and disposal
costs
373
-------
• On-site treatment of hazardous wastes
at refineries or petrochemical units to:
- meet existing and projected stan-
dards for land disposal
- minimize waste volumes and dispos-
al costs
- minimize liabilities of transportation
and disposal of hazardous waste
CF Systems is a subsidiary of Morrison
Knudsen Corporation, a $2 billion diversi-
fied services company with primary em-
phasis in the engineering, construction,
and environmental sectors. CF Systems
supplies engineered solvent extraction
systems and remediation services to the
refining, process, and environmental in-
dustries. Several commercial-scale sys-
tems employing the proprietary technolo-
gy have been built and the technology has
been specified for the remediation of a
Superfund sites.
CF Systems successfully completed its first
commercial Best Demonstrated Available
Technology (BDAT) treatment operation at
the Star Enterprise Refinery in Port Ar-
thur, Texas. The propane-based solvent
extraction unit processed listed refinery
wastes (F and K) and produced treated
solids that met land-disposal treatment
levels. The unit was operated continuous-
ly from March, 1991 to March, 1992 and
had an on-line availability in excess of
90%.
The first commercial wastewater treatment
unit was put into service in October, 1991
at the Clean Harbors waste treatment
facility located in Baltimore, Maryland.
This unit is a COo-based extraction unit
designed to treat large volumes of waste-
water containing hydrocarbon contami-
nants.
CF Systems has been selected by the Tex-
as Water Commission (TWC) and the EPA
as the sole-source supplier of a solvent
extraction system for remediation of the
United Creosoting Superfund site in
Conroe, Texas. This unit will employ a
batch process to treat non-pumpable sol-
ids containing poly aromatic hydrocarbons
(PAHs) and dioxins. The unit capacity
will be in excess of 200 tons per day
(TPD).
SITE DEMONSTRATION
PROGRAM
The SITE program demonstration of the
CF Systems solvent extraction technology
was conducted to obtain specific operating
and cost information that could be used to
evaluate the potential applicability of the
technology to Superfund sites. The dem-
onstration was conducted concurrently
with dredging studies managed by the
U.S. Army Corps of Engineers at the New
Bedford Harbor Superfund site in Massa-
chusetts.
Contaminated sediments were treated by
CF Systems' Mobil Demonstration Unit
(MDU), which had a rating of 20 barrels
per day of sludge feed, on a once through
basis. The MDU used a liquefied propane
and butane solvent mixture to extract
organics from contaminated sediments.
During the tests, treated sediments were
recycled through the unit to simulate the
design and operation of a full-scale, four-
stage unit. Recent MDU operation has
employed a batch processing technology,
similar to that now proposed for full-scale
remediation.
The MDU was tested on sediments ob-
tained from New Bedford Harbor, Massa-
chusetts which contained PCB concentra-
tions of 350 and 2,575 parts per million
(ppm). Table 2.1 summarizes the feed
and treated solids PCB concentrations for
two of die tests.
The objectives of the SITE testing included
an evaluation of:
(1) the unit's performance,
(2) system operation,
(3) health and safety considerations,
374
-------
(4) equipment and system materials
handling problems,
(5) projected system economics.
The conclusions drawn from the test re-
sults are given in Table 2.2, with an evalu-
ation of the findings versus current devel-
opments in table 2.3. The primary conclu-
sions were:
Polychlorinated biphenyl (PCB)
extraction efficiencies of 90 percent
were achieved for New Bedford
Harbor sediments containing PCBs
ranging from 350 to 2,575 ppm.
Concentrations of PCBs in the clean
sediment were as low as 8 ppm.
Some operating problems occurred
during the SITE tests; such as, inter-
mittent retention of solids in system
hardware and foaming in the treated
sediment collection tanks.
Operation of the MDU at New Bed-
ford did not present any threats to
the health and safety of the opera-
tors or local community.
The projected cost of applying the
technology to a full-scale cleanup at
New Bedford Harbor ranged from
$148 to $447 per ton. The predicted
onstream factor for the full-scale
commercial unit is the variable that
introduces the greatest uncertainty
to the cost estimates.
Table 2.1
Summary of "Site Test Data"
Stage
Number
Feed
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
Stage 7
Stage 8
Stage 9
Stage 10
Test 2 PCB
Cone.
(ppm)
350
77
52
20
66
59
41
36
29
8
40
Cumulative
PCB
Removal %
78
85
94
81
83
88
90
92
98
89
Test 4 PCB
Cone, (ppm)
2575
1000
990
670
325
240
200
Cumulative PCB
Removal %
61
62
74
87
91
92
375
-------
Oi
>J
ON
Performance Test Objective
Removal Efficiency
Foaming
Flow Control
Solids Retention
Extract Quality
Health & Safety
On-Stream Factor
Propane Loses
PreTreatment /PostTreatment
Remediation Costs
Table 2.2
New Bedford Harbor SITE Demonstration Findings
Findings
The technology can separate organics from harbor sediments, sludges, and soils. PCB
extraction efficiencies greater than 90 percents were achieved for New Bedford Harbor
sediments and treatment levels as low as 8 ppm PCBs were attained.
Foaming of treated sediments occurred.
Solvent flow fluctuated widely and caused the solvent to feed ratio to fall below specifications.
Solids were retained in process hardware.
Solids were observed in organic extracts.
No significant releases of pollutants to the atmosphere or surrounding area soils occurred.
Results of the demonstrations tests show that the CF Systems technology is capable of
operating without risk to personnel or the surrounding community.
For the purposes of the economic evaluation an 85 % availability was assumed. This level of
availability was considered optimistic in the Applications report.
Propane losses were not quantified in the evaluation; however, they were reported to be
significant.
Pretreatment (removal of coarse solids) was required to maintain feed sediment particle sizes
below 1/8 inch. Post-treatment such as thermal destruction of the concentrated extract may be
necessary.
The Applications Analysis Report estimated total treatment costs for New Bedford Harbor
(Pile to Pile) to be $450/ton for Hot Spots and $150/ton for the Base Case. These were
considered to be optimistic in view of the required availability to achieve these costs.
-------
Table 2.3
Historical Performance Comparison SITE Program to Present Day
Test Objective Performance/ New Bedford
Design Criteria || Demonstration
Removal Efficiency
Foaming
Flow Control
Solids Retention
Extract Quality
Health & Safety
On-Stream Factor
Propane Loses
Pretreatment / Post-Treatment
Remediation Costs
Test 2: 92 % PCB
Test 4: 97.5% PCB
Caused Poor
Performance
Caused Poor
Performance
Cross Contamina-
tion
Disposal Costs
No Problem -
Design Criteria
85% Estimate
10% Of Feed
Sieving
-------
BENCH AND PILOT SCALE
WORK
CF Systems has been operating a bench-
scale testing facility since 1980 and its
experience in performing laboratory-based
feasibility studies for both commercial
clients and governmental agencies is con-
siderable. The composition of samples
sent to CF Systems for testing has ranged
from dry soils/sludges to sediments and
wastewaters. These samples have origi-
nated from a variety of sources including,
Superfund and RCRA Closure sites, on-
going waste streams generated from in-
dustrial operations, and planned remedia-
tion sites. The results obtained from these
bench-scale extractions have been used to
develop a broad experimental data base
for the extraction of organics from hazard-
ous wastes using a variety of liquefied
gases as extractive solvents. These data
are the foundation for the different sol-
vent extraction units CF Systems has de-
signed and built. Typical bench-scale data
is given in Table 3.1.
The MDU, used for the New Bedford
Harbor study, has been modified to allow
for operation in a Batch treatment mode
for non-pumpable wastes and sludges.
This, and other changes in the system
design and operation, has resulted in
significant enhancement of the technology
for remediation service.
The following is an outline of some of the
studies carried out at bench scale and pilot
scale.
Massachusetts Superfund Site
CF Systems was contracted to perform a
bench scale treatability study to determine
the feasibility of using liquefied propane
as a solvent to remediate PCB-contaminat-
ed soils from a Superfund site in Massa-
chusetts. This study was done as part of
the remedial design phase of work at this
Superfund site, and was performed at CF
Systems testing facility under a TSCA
R&D permit granted from EPA Region I.
The results from this study (Table 3.2),
indicate that the composite sample (i.e.,
697 ppm PCBs) was reduced to 0.36 ppm
after six stages of extraction. The second
"hot spot" sample, which contained 13,800
ppm PCBs in the feed, was reduced to 1.5
ppm after six stages of extraction. The
percent reduction of PCBs from these two
soil samples was calculated to be 99.95%
and 99.99% respectively, and are an indi-
cation of the high PCB removal rates that
can be achieved using liquid propane as a
solvent.
Star Enterprises Refinery, Port Arthur,
Texas.
The pilot-scale Mobile Demonstration Unit
(MDU) had its initial start-up at Star En-
terprise's Port Arthur refinery in Septem-
ber, 1987. Waste materials processed
through the unit included contaminated
soils from a clay pit, ditch skimmer
sludge, and tank bottoms. The resulting
treated solids product streams were ana-
lyzed by Star and the concentration of
individual components, including PAHs
and volatiles, were found to be well below
the regulatory levels established for the
treated solids.
PCB-contaminated NPL site in Augusta,
Maine
This bench-scale treatability study was
carried out to determine die feasibility of
using CF Systems' solvent extraction pro-
cess to treat five soil and sediment sam-
ples collected from a PCB-contaminated
Superfund site in Augusta, Maine. A
variety of soil types (i.e., clay, fill, and
sediment) were processed and it was dem-
onstrated that liquefied propane extraction
was capable of reducing the PCB levels to
below 1 ppm. The overall PCB removal
efficiency for this study exceeded 99%,
with PCB concentrations in the treated
solid as low as 30 ppb. Results from this
378
-------
bench-scale study resulted in a contract
for CF Systems to conduct a Pilot Scale
Remedial-Design Treatability Study at the
site.
PCB-contaminated Naval Station site in
Adak, Alaska.
The purpose of this bench-scale treatabili-
ty study was to determine the feasibility
of using CF Systems' solvent extraction
process for the remediation of PCB-con-
taminated soils at a Superfund site in
Alaska. Samples were collected from the
site and tested. The results of this study
indicated that solvent extraction utilizing
liquid propane as the extractive solvent
was an effective treatment process for the
remediation of PCB-contaminated soils.
Analytical results showed that an overall
PCB reduction of 99% was achieved in the
study.
Waterways Experiment Station,
Vicksburg, Mississippi.
In April of 1989, CF Systems conducted
a pilot-scale technology demonstration
for the EPA at the Waterways Experi-
mental Station in Vicksburg, Mississippi.
CF Systems utilized its Mobile Demon-
stration Unit (MDU) for this study. The
purpose of this demonstration was to
develop treatment standards for the
KO48-KO52 listed refinery wastes, and
CF Systems' solvent extraction process
was in fact the
only solvent extraction technology to be
field-tested for that purpose. The results
of this treatability study were used by the
EPA to develop BOAT treatment stan-
dards for five listed refinery wastes.
United Creosoting Superfund Site,
Con roe, Texas
CF Systems conducted a pilot-scale treat-
ability study for EPA Region VI and the
Texas Water Commission at the United
Creosoting Superfund site in Conroe,
Texas. The objective of this treatability
study was to evaluate the effectiveness of
CF Systems' solvent extraction process
for the remediation of soils containing
creosote-derived organic contaminants,
such as PAHs, PCPs, and Dioxins.
Treatment data from this field demon-
stration showed that the overall concen-
tration of PAHs were reduced by 95.7%
in the two soil samples, and subsequent
full-scale treatment data indicates that
PAH reductions of > 99% are possible
through the optimization of extraction
operating conditions. Based on the
results of this pilot-scale study, CF Sys-
tems' critical fluid solvent extraction
process was selected for full-scale remed-
iation at the United Creosoting Super-
fund site.
379
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OJ
00
o
TABLE 3.1
SELECTED CF SYSTEMS TREATABILITY STUDIES
Concentration (PPM)
Client
Texas Water Com-
mission
Metcalf & Eddy
Occidental
Chemical
Central Maine
Power
U.S. Navy
NY Dept. of Envir
Conservation
Metcalf & Eddy
Kerr McGee
Site
United Creosoting
Superfund Site
Pine St. Canal
Superfund Site
No. Tonawanda
O'Connor Superfund
Site
Adak Naval Air Station
Booth Oil Site
Norwood Superfund
site
Wood Treating Site,
OK
PCOC's
PAHs
PCPs
Dioxins
PAHs
Dioxins
PCBs
PCBs
TPHs
PCBs
TPHs
PCBs
Dioxins
PAHs
PCPs
Feed
2324.0
33.9
312.0
240.
23. ppb
113.
305.
7850.
12.4
40.3
13,800.
7.068 ppb
In progress
After Removal
Treatment | Efficiency
51.7
5.59
14.8
16.
0.6 ppb
3.4
2.2
34.
<0.24
0.24
1.4
0.09924 ppb
In progress
97.7%
83.5%
95.3%
93.4%
97.4%
97.0%
99.3%
99.6%
>98.%
99.4%
>99.9%
>99.9%
-------
Table 3.2
PCB Contaminated Superfund Site
Solvent Extraction Results
Sample
PCB in Feed
PCB After
Extraction Stage
No.
1
2
3
4
5
6
Composite
Sample
(ppm)
697.0
14.0
1.4
2.9
0.2
0.07
0.3
Cumulative
% Removal
97.99
99.80
99.58
99.97
99.99
99.96
Hot Spot
Sample
(ppm)
13800
178
26.8
10.3
5.3
2.6
1.4
Cumulative
% Removal
98.71
99.81
99.93
99.96
99.98
99.99
COMMERCIAL-SCALE
PROCESS
CF Systems' proprietary Solvent
Extraction soil treatment process involves
the use of liquefied gases, such as
propane, as the solvent to extract and
separate organic contaminants from soils
and sludges. The unique physical
properties of a liquefied gas, such as low
viscosity, density, and surface tension,
result in a solvent with significantly
higher rates of extraction in comparison to
conventional solvents. Additionally, the
enhanced physical properties accelerate
the rate of gravity settling of the
soil/solvent mixture following extraction
which broadens the applicability of the
process to include the treatment of fine
clays and silty sediments. Due to high
volatility, liquefied gas solvents are easily
recovered from the waste matrix which
minimizes the potential for solvent
residues in the treated soils.
CF Systems has successfully completed
the first commercial on-site BOAT
treatment operation at the Star Enterprise
Refinery in Port Arthur, Texas. The
propane-based solvent extraction unit
processed listed refinery K- and F-wastes
and produced treated solids that met land-
ban requirements. The unit operated
continuously from March 1991 to March
1992, with an on-line availability in excess
of 90%. Following fixation for heavy
metals, the treated solids were disposed of
in a Class I landfill. During operation,
100% of the feed material was treated to
meet the land-ban specifications. Multiple
feeds, including API separator solids, slop
oil emulsion solids, slop oils, and
contaminated soils were treated. Typical
381
-------
treatment results for a refinery waste are
given in Table 4.1.
The first commercial wastewater treatment
unit was put into service in October 1991,
at the Clean Harbors waste treatment
facility in Baltimore, Maryland. This unit
is a CO2-based extraction unit designed to
treat large volumes of wastewater
containing hydrocarbon contaminates.
Recovered hydrocarbons will be disposed
of in an incinerator while treated
wastewater will be discharged to the local
POTW.
CF Systems has been selected by the
Texas Water Commission (TWC) and the
EPA as the sole-source supplier of a
solvent extraction system for remediation
of tlie United Creosoting Superfund site
in Conroe, Texas. This unit will employ a
batch process to treat non-pumpable
solids containing poly aromatic
hydrocarbons (PAH's) and dioxins. Unit
capacity will be in excess of 200 tons per
day.
Process Description
The CF Systems solvent extraction process
for remediation of organic-contaminated
soils and sediments is comprised of the
following systems:
A Feed Delivery System
An Extraction/Gravity Settling System
A Treated Solids Filtration System
A Solvent Recovery System
A Vent Gas Recovery System
Feed Delivery
Soil delivered to the process battery limits
is screened to less than 1/4 inch to remove
oversized material. Oversize materials are
segregated and reprocessed to an accept-
able size through the use of mechanical
size reduction equipment. Oversized
material can also be washed to remove
attached "fines' and surface
contamination. The screened soil is sent
to the extractor(s) via an enclosed
conveyor/screw auger system. In most
cases, die process does not require other
forms of soil pretreatment, such as
dewatering or the addition of chemical
reagents.
Extraction System
The extraction system is comprised of one
or more agitated extraction vessels where
contaminated soil is contacted widi
liquefied propane. The number of
extraction vessels and die size of die
vessels and agitators determine the rate of
throughput and die degree of organics
removal. Exact configuration of the
extraction system is determined during
the bench test phase of die project.
Contaminated soil is fed to die extractors
where it is contacted with liquid solvent
pumped from die Solvent Recovery
System. Following die extraction step,
the agitators are stopped and settling of
the soil from the solvent occurs. Settling
of soil from the solvent occurs rapidly in
the extraction vessel due to die enhanced
physical properties of the solvents.
Following settling, die solvent/organics
phase is drained to the Solvent Recovery
System where the solvent is recovered.
The extraction-settling-draining process is
repeated in the extraction vessel until die
extraction is complete. The final step
involves injecting water into the extraction
vessel in order to displace residual liquid
propane, which is insoluble in water, and
is displaced from die top of die extractor.
This final water displacement step in die
extractor vessel forms a treated soil/water
slurry that is fed to a belt filter press
operation.
Filtration System
This system includes the soil/water slurry
day tank, belt filter press, and all required
drums and pumps for routine filter press
operation. Treated filter cake from the
382
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filter press has high compressive strength,
and is suitable for land disposal. Treated
filter cake also has the appropriate
moisture content for the addition of
solidification/stabilization reagents for the
fixation of metals, if required.
Solvent Recovery System
This system contains an extract surge
vessel, the main solvent recovery still, a
solvent condenser and a solvent recycle
pump. The solvent/organics mixture
(extract) flows from the extract surge drum
to the main solvent recovery still, where
the solvent is vaporized using steam, hot
oil or the heat from a vapor recompression
cycle.
Solvent vapor from the still is condensed
and flows to the solvent storage drum.
The solvent recycle pump takes a gravity
suction from this drum and pumps liquid
solvent, on demand, to the extraction
system.
From the main solvent recovery still
reboiler, organic-rich extract flows to a low
pressure organics recovery drum, where
residual solvent is removed from the
extracted organics and sent to the Vent
Gas Recovery System. Recovered
extracted organics are sent to storage and
disposal.
Vent Gas Recovery System
A low pressure compressor recovers low
pressure solvent vapor from the organics
recovery drum, recovered organics storage
and from low pressure vents from the
treated soils system. The compressed
recovered solvent is returned to the main
still for recycling.
CF Systems' Solvent Extraction: Benefits
The primary benefit of using CF Systems'
solvent extraction process at large scale
organic-contaminated sites is low
treatment costs. The low operating (i.e.,
utility) requirements for this process
results in treatment costs in the range of
$100 to $350 per ton at sites containing
greater than 10,000 cubic yards of soil.
The process has been commercially proven
at Star Enterprises where it operated for
over one year, 24 hours a day, seven days
per week, with an on-line availability
exceeding 90%.
The systems is totally enclosed, with no
process vents or emissions, thereby
reducing the level of complexity associated
with obtaining required permits.
No chemical additives or reagents are
required for this process, and the organics
are extracted and recovered unchanged
and unreacted. For most applications, the
pretreatment requirements are minimal,
consisting of size reduction to less than 1
inch particle size diameter.
The process is operated at ambient or
near-ambient conditions, thereby
eliminating die potential for the formation
of toxic compounds and their subsequent
release to the environment.
383
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Table 4.1
TYPICAL TREATED SOLIDS - REFINERY WASTE
Compound
Volatiles
Benzene
Ethylbenzene
Toluene
Xylene
Semi-Volatiles (PAH)
Naphthalene
Phenanthrene
2-Methyl Phenol
Anthracene
Benzo(A)-
Antliracene
Pyrene
Chrysene
Benzo(A)-
Pyrene
Phenol
4-Methylphenol
Bis(2-E.H.)
Phthalate
Di-n-Butyl
Phthalate
Typical Feed
(mg/kg)
65
130
250
480
350
450
10
37
5
35
19
5
10
10
10
ND
Product
(mg/kg)
<1.0
<1.0
<1.0
1.5
1.8
<1.0
ND
<1.0
ND
<1.0
ND
ND
<1.8
ND
ND
. ND
Percent
Removal
>98
>99
>99.4
99.7
99.5
99.8
N/A
>97
N/A
>97
N/A
N/A
>90
N/A
N/A
N/A
BOAT
(mg/kg)
14
14
14
22
42
34
6.2
28
20
36
15
12
3.6
6.2
7.3
3.6
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COMMERCIALIZATION OF INNOVATIVE TECHNOLOGIES -
CHALLENGES AND SOLUTIONS
(A Technology Vendor's Perspective)
Frederic A. Eidsness, Jr., Director of Government Relations
Michael J. Taylor, P.E., Senior Vice President
Alistair H. Montgomery, Director -
Corporate Waste Treatment Technologies
Canonie Environmental Services Corp.
6300 South Syracuse Way, Suite 300
Englewood, Colorado 80111
(303) 290-8336
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COMMERCIALIZATION OF INNOVATIVE TECHNOLOGIES-
CHALLENGES AND SOLUTIONS
A Technology Vendor's Perspective
INTRODUCTION
Commercializing innovative technologies for the remediation of hazardous waste is a
task fraught with obstacles and challenges. Experience in the field indicates that
many of the obstacles and challenges can be overcome when the industry, including
owners, regulators and purveyors of innovative technologies, work together.
However, should the various parties continue to operate from their own isolated
spheres without considering the others' needs, goals and constraints, then the use of
innovative technologies will be stifled and new cost-effective solutions will not be
applied to the hazardous waste problems of today and the future.
Even with more harmonious institutional relations, the current mind-set of the federally
driven "command and control" regulatory program for cleaning up contaminated sites
thwarts the commercial development and application of innovative technologies. That
mind-set is the false assumption that complex sites with complex wastes can be
adequately understood based on "studies" that justify a selected design of a total site
remediation system that will work. Consequently, hazardous waste generators are
being asked to sign on up-front for implementation of a "total solution" with imperfect
knowledge, unproven technology and astronomical costs. These risk-posing factors
flow downhill from site owners to remediation contractors and vendors in the form of
contracts, hence, the deterrent to owners, contractors and vendors to invest in the
development and use of innovative waste treatment technologies.
i
This paper discusses several key obstacles which emerge from this mind-set that must
be overcome to foster innovative technologies in the market place. Solutions to
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overcoming these obstacles are also presented. These obstacles and solutions are
based on reaMife experiences of bringing, or attempting to bring, innovative
technologies to the commercial level in the hazardous waste industry of today.
With a co-operative spirit, a more workable approach to remediating sites and a few
changes in the contractual methods of handling these endeavors, innovative
technologies can be developed and commercialized to achieve more cost effective
solutions to our hazardous waste problems.
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OBSTACLES AND APPROACHES TO SOLUTIONS
Predicting Performance (or Lack Thereof)
Comprehensive long-term performance of innovative technologies cannot be predicted
with any degree of certainty for the complex waste and subsurface conditions that
exist at hazardous waste sites. Yet innovative technologies often may represent the
most cost-effective method of cleaning all or portions of the site. However, in today's
regulatory approach, agencies are asked to chose and owners are asked to accept a
technology based on site investigatory information and to guarantee that the
technology will work to clean the site to often unrealistically low levels of
concentration. Without the certain predictability, the innovative technologies often
do not make the first cut. Even if the technology is selected, the purveyors of the
technology cannot predict long-term performance to the unrealistic low levels for the
ill-defined complex conditions based on the limited investigatory site information.
They therefore do not bid the work, or have to add such high contingencies that the
technology does look financially attractive. Only if they are allowed to apply their
technologies in a step-wise sequential remediation approach with near-term realistic
goals can they successfully apply and commercialize their technologies.
Reducing Microscopic Regulation
The current ad-hoc system for determining residual waste stream performance
standards during construction impedes innovation. The characteristics and volumes
of residual wastes generated by the application of treatment technologies during the
construction phase are not predictable at bench-scale or even pilot-scale testing
because of the varying site conditions and waste characteristics encountered as site
remediation proceeds. Yet, engineering designs attempt to define in absolute terms
the performance standards and emission rates that must be met during construction.
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When remediation is undertaken under the Superfund program where Potentially
Responsible Parties (PRP) have assumed the lead role, residual waste stream
performance standards and rates are typically incorporated into Remedial Action Plans
which themselves are considered a part of Consent Decrees and Records of Decision.
Therefore, any change in performance standards resulting from site conditions during
full-scale remediation may require agreement of all the parties to the decree including
the EPA, Department of Justice, State and PRPs. When Superfund projects are
financed by the Fund and construction administered by the U.S. Army Corps of
Engineers (COE) under an agreement with EPA, contractors and technology vendors
are faced with convincing the COE. For historic, cultural reasons, the COE tends to
treat remediation projects as standard civil engineering public works project where
engineering designs tend to be viewed as sacrosanct.
Within this ad hoc decision framework, risks and uncertainties abound. Vendors are
expected to warrant that they can meet these prescribed emissions performance
standards and limitations. Failure to meet them usually results in shutdowns and
protracted negotiations. Enforcement actions and penalties are a possibility.
The market responds to these risks and uncertainties in the only way it can, by
increasing contingencies and bid prices, taking the chance the problem will not arise
and fighting it out with the owners and regulators (the change order route) if it does,
or declining to bid the technology. None of these alternatives is a good option
financially or in terms of developing and maintaining good vendor and technology
reputation in the industry.
A decision protocol is needed that will allow performance standards to be established
based on full-scale proof-of-process testing on site wastes that will assure the
technology will operate to its best capability and assure that the off-site public is
protected and the on-site condition does not worsen. Such a decision protocol should
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allow technologies to be operated uninterrupted from proof-of-process through to
completion, provided that the off-site public is protected.
Risk Sharing
To realize savings through the use of cost-effective, innovative technologies, the
regulators, the owners of the site and the vendors of the technologies must share the
risk as well as the benefits. Each of these entities needs to understand that it cannot
regulate, contract and/or receive payments as would when more developed, mature
technologies are used. The risk sharing and the rewards must be fair and equitable
to all concerned. Regulators must accept the premise that as long as the short-term
treatment activities do not pose an unacceptable risk to the off-site public or worsen
the on-site condition, the technology should be allowed to operate.
Institutional Attitudes and Mechanisms
In our industry today there is a tendency to think that the key to any problem, in this
case the commercialization of innovative technologies, has at its core an "engineering
solution." In reality, the problems are institutional and, once resolved, the engineering
component, that which most of us are trained to concoct, can be brought to the table.
The main barriers to commercialization of innovative technologies are, at their core,
institutional problems. In summary, they include: regulator's "command-and-control"
and enforcement mentality; regulators, owners and contract administrators penchant
to view the use of innovative technologies as no different than standard civil
engineering projects; tendency to pass on risk to remediation contractors and
technology vendors; and, a mind-set "letting the perfect be the enemy of the good"
in terms of designing solutions to complex hazardous waste sites.
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Canonie Environmental Services Corp. (Canonic) has had the most success in
commercializing technologies where the risks have been shared and the institutional
mechanisms for the project have been well developed and mutually understood by the
parties involved. Case studies discussed herein include such projects as the McKin
Super-fund site where the Low Temperature Thermal Aeration (LTTA®) Technology
was originally developed and commercialized; the Gould Superfund site where the
patented Waste Battery Treatment System is being commercialized; and the San Jose
Superfund site where the Accelerated Vacuum Extraction Process was developed and
applied on a commercial scale.
Canonie also has commercialized innovative technologies on projects where the risk
sharing and the institutional mechanisms were less than desired and the results have
not been satisfactory. Even when the technology was technically successful, the
financial burden on the vendor and the schedule of performance have been so
adversely effected that participation on future projects of the type become very
unattractive and commercialization of the technology is severely curtailed. Such was
the case on the Wide Beach Superfund Site and the Waukegan Harbor Superfund Site
where the SoilTech Anaerobic Thermal Processor (ATP) Technology was applied in
two different modes for the first commercial applications of this technology.
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COMMERCIALIZATION EXPERIENCES - CASE STUDIES
Case Study #1 - McKin Superfund Site
The Mckin Superfund site provides a good example of how innovative
technologies can be applied at a commercial level while still being developed, if
the parties are cooperative and the risks are shared^ This project was done during
the early days of the Superfund program when such innovation and risk sharing
were common. Low Temperature Thermal Aeration fLTTA^J was the innovative
technology developed and used in the successful cleanup. At that time, no
commercial thermal aeration systems existed.
The McKin Superfund site was formerly a liquid waste storage, treatment and
disposal facility for volatile organic solvents, chemicals and heavy oils. As a
result of improper operation, the soils and ground water were impacted by VOCs
and oils. The site was also subject to a high degree of public exposure because
it was within 300 feet of several residences. This site was ranked No. 32 on the
National Priorities list at the time of the Record of Decision (ROD) in 1985.
The ROD had called for the soi/s to be excavated and disked on the surface to
remove the VOCs prior to being backfilled. However, the VOC concentrations
were to be kept below a certain level at the site boundary. Disking to remove
VOCs would certainly have caused exceedances at the boundary and would have
taken an unacceptably long time to complete.
Canonie, while working with one of the main PRPs, realized that ex-situ
processing was the only way to accomplish the intent of the ROD without
causing unacceptable emissions. However, to design, build and permit a system
would have caused the project to go far beyond the specified completion date,
resulting in substantial costs, and still would not result in a proven commercial-
level treatment technology.
Canonie was aware of an existing asphalt aggregate dryer that had an air permit
to work in the area of the McKin Site. A technical review indicated that the heat
and mixing action in the dryer would vaporize the organics in the soil and clean
the soil to meet the specified criteria. The vapors could not, however, be released
into the air. Therefore, to capture the vapors and assure that the provisions of
the dryer air permit were not violated, Canonie engineered an extensive and
innovative air treatment train using primarily existing air treatment components
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from other projects or commercially available, including vapor phase carbon and
slurry scrubber. This combination of existing and engineered systems was the
initial formulation of the patented Canonie L TTA * system.
At the time the LTTA® treatment train was proposed to the owners and :th^
agencies on the McKin project, there was no guarantee that the system would
clean the soils, would not violate emission standards at the site boundary or
would not cause microscopic emission excursions of the internal components of
the system: Yet the system offered the owners the potential for substantial cost
savings and the ability to meet the project schedule. All that was needed was an
agreement to share some of the risk of applying the system at full production
level and a cooperative spirit in entering the project.
No threat to the residents living near the site could be tolerated, and they had to
be part of the overall plan. Consequently, a door-to-door campaign was
implemented to discuss what was to occur, what precautions were going to be
taken and what the risks and rewards (i.e., the cleanup of the site) would be.
The public supported the total program.
The system was mobilized and test runs were conducted. The system was
adjusted to improve performance. Full production was implemented under the
monitoring of emissions and treated soils by the regulatory agencies which was
conducted at the boundaries of the site and not at the microscopic emission
points at, or internal to, the equipment. Equipment performance criteria for less
innovative types of technology were not imposed on the unit (i.e., the agencies
did not try to apply incineration performance criteria merely because this was a
new type of thermal device). The owners, in cooperation with the equipment
developer/vendor, monitored the costs.
The project was the first NPL site cleanup to be successfully completed in EPA
Region L The remediation was used by the EPA as an example of success of the
Superfund program. The owner received a clean site at less than the original
estimated cost and the contractor was adequately reimbursed for his efforts.
Most important, the public was the all-around winner.
Case Study #1 (Continued) - McKin Superfund Site
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Case Study #2 • Wide Beach Superfund Site
The application of the innovative SoilTech ATP Technology to remediate PCB-
contaminated soiis at the Wide Beach Superfund Site represents an case wherein
technical success can be achieved in spite of non-cooperative behavior on the
part of some of the parties, provided, however, that the developer/vendor is
willing to take a large portion of the financial and performance risk.
The Wide Beach Superfund site was a residential area on the shores of Lake Erie
near Buffalo, New York, where PCB-contaminated oils had been used for dust
suppression on community roads. The PCBs existed throughout the roadways as
well as in driveways and lawns. The ROD called for the PCB-contaminated soils
to be excavated and treated with a dehalogenation process, a new and
developing technology. The original estimated quantity to be treated was nearly
20,000 tons. The project was managed by the COEas the Contracts Manager for
the EPA.
Even though dehalogenation had never been accomplished at a commercial level
anywhere in the world, the COE wrote a standard performance specification and
solicited unit-price hard bids for the work. The successful bidder for the
treatment portion of the contract was a technology developer/vendor of a batch
process for dehalogenation which had been doing some test work on the site.
The technology was, however, not developed much beyond the bench-scale, or
at most the pilot-scale level, and application of this process to full-scale
remediation was speculative at best. The technology developer was supported
in the bidding and contracting efforts by the prime contractor, who was
responsible for the excavation and other miscellaneous work.
When the prime contractor began to realize the excessive risks he had assumed,
he began to seek alternate solutions. He discovered that Canonie, through its
subsidiary company, SoilTech, had a technology developed to commercial level
that would desorb the PCBs from the soil. The addition of the dehalogenation
capability looked feasible, but was not proven. Desorption was a developing
innovative technology already, and adding the dehalogenation process made
matters even more innovative and speculative.
Since the contractual and bidding mechanism for this project was not geared
toward risk sharing and application of innovative approaches, the prime contractor
could only apply the SoilTech ATP Technology with dehalogenation systems
added by submitting a Value Engineering Proposal with fixed unit prices. SoilTech
was asked to supply these prices and to take all the risk that
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performance would be successful. There was no mechanism for nor willingness
by the COE to allow any risk sharing or to allow adjustments for changing site
conditions, equipment performance on this innovative application, or other
adjustments typically required to respond to the needs of applications of
innovative technologies at the commercial level on a first-time basis. The COE's
attitude was (and continues to be) that the developer and vendor should take all
the performance and financial risk.
On the Wide Beach project, Canonie and SoilTech elected to take the risk.
Canonie/SoilTech had to agree that no compensation would be received for the
mobilization and testing if the processing was not successful in this first-time
commercial level application. This was a gamble of over $ 1 million, not something
a small company with a new innovative technology would be likely, or able, to
take.
The gamble proved to be a technical winner. The SoilTech A TP Unit successfully
removed and dechlorinated the PCBs in the soil and provided soils with non-
detectable levels of PCBs after treatment. The gamble, however, turned out to
be a financial disaster due to the rigid contractual position of the COE and its
inability and unwillingness to share in any of the risk.
As with most Superfund work, the site characterization was valid to define the
extent of the contamination, but was inadequate in defining the parameters
necessary to apply and adequately price the application of the treatment
technology, especially an innovative treatment technology.
When excavation began, it was discovered that the majority of the soils to be
treated were very clayey in nature, more so than expected from the site
characterization. Even though the equipment had to be adjusted significantly and
the production rate had to be slowed (with attendant cost impacts) to accomplish
the technical success {not an unusual occurrence when applying innovative
technology at the commercial level for the first time), the COE would not consider
an adjustment in the quoted unit price. The developer/vender of the technology
(Canonie/ SoilTech) was told to keep working regardless of the costs and
difficulty.
Case Study #2 (Continued) - Wide Beach Superfund Site
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The project continued, and the quantities of treatment doubled; again, not an
unusual occurrence at a CERCLA site. The innovative application of the SoilTech
A TP Technology with dechlorination capabilities continued to perform well and:
cleaned over 42,000 tons of soils to non-detectable levels. This was the first
commercial application at this scale world-wide and was hailed by EPA and the
scientific community as a major success. {The technology received a national
award in the Association of Bay Area Governments for the best innovative tech-
nology.) However, the COEhas denied all claims and continues to administer the
contract as if the work were standard ordinary construction work,
Case Study #2 (Continued) - Wide Beach Superfund Site
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Case Study #3 - Gould Battery Superfund Site
Gould Battery Superfund site in Portland, Oregon, is another example of how
innovative treatment technology can be developed and applied through joint
cooperation among the owners, the regulators and the technology vendors. This
project is a first-of-a-kind and has significant potential for the remediation of
similar sites nation-wide.
Automobile batteries were recycled at the site over a period of 32 years. Lead,
copper and other metals were extracted from the batteries by crushing,
separation and smelting methods. The waste materials, principally battery
casings and furnace products (matte, slag, etc.) were used as fill material both
on and around the property. The site was placed on the NPL in 1983 and a
Remedial Investigation/Feasibility Study (RI/FS) was completed in 1988. The
ROD issued in 1988 specified excavation, treatment and recycling of fill material
as the preferred remediation method. Specifically, the selected remedy
contemplated recycling plastics, hard rubber (ebonite), metallic lead and lead
oxide/lead sulfate products from the process. The feasibility study, however,
failed to demonstrate that the requirements of the ROD could be achieved with
any known treatment, technology, including processes then being used
commercially for automobile battery recycling.
At this point in the project, the owner and the EPA entered into a Consent Decree
to conduct predesign studies to collect information on the treatment, recycling,
and health and safety aspects of the project. Canonie was retained to perform
this work, which resulted in the successful development of innovative technology
for the treatment of the wastes on the Gould Superfund site.
In electing to pursue the predesign studies route, the EPA avoided the pitfall of
specifying a remediation approach which could not be met with existing
technology and which would have resulted in a costly failure for both the
regulators and the owners. Realizing there was no precedent for remediating
abandoned battery wrecking sites, Canonie sought to develop a treatment
approach which would minimize the risk associated with technology innovation.
Canonie accomplished this by characterizing the site from a treatment rather than
contamination standpoint. Existing unit processes, used previously in the mining
industry, were selected for the conceptual process flowsheet, but configured in
such a way as to meet the site regulatory requirements for the remediation. The
process developed by Canonie hot only produced the required recyclable
products, but addressed water treatment and off-site disposal issues byreducing
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or eliminating toxic chemicals from the process. Public health exposures to dust
and air borne lead emissions were mitigated by developing and incorporating a
wetting agent/dust control system which is totally compatible with the process.
This approach resulted in a significant reduction of the remediation cost over
projections made during the R//FS phase* Most importantly, the treatment
technology was developed through the stages of bench-scale, pilot-scale and on-
site demonstration. • •
In the Gould project the risks were shared in some proportion by the participants.
The owner paid for the technology development, but may receive revenue from
its application on other sites. The EPA took the risk that a process and/or
approach could be developed to meet the requirements of the ROD. The
technology developer (Canonie) took the risk that the remediation project could
be completed at a cost substantially below the amount projected in the RI/FS.
By performing the work on a target value basis, Canonie had the incentive to
complete the project at even lower costs if possible.
The confidence built among the participants during the predesign studies phase
was sufficient to persuade the owners to negotiate the remediation contract with
Canonie on a sole-source basis. This relationship continues to strengthen during
the construction phrase of the project through the participation of the owners,
regulators, and the contractor in resolving problems as the remediation
progresses.
Case Study #3 (Continued) - Gould Battery Superfund Site
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Case Study #4 - Waukegan Harbor Superfund Site
The SoilTech ATP Technology applied at the Waukegan Harbor Superfund site
represents an example of a technical success for an innovative technology, but
where the variable nature of the site conditions and where micro-monitoring of
the equipment operation by the agencies caused unwarranted financial burden on
the developer/vendor of the technology.
The sediments of the Waukegan Harbor and an adjacent stream were heavily
impacted with PCBs with concentrations in excess of 20,000 parts per million
(ppm). This site ranked No. 86 on the National Priorities List. Remediation
alternatives were limited because the harbor was located adjacent to a public
beach and was used for both recreational and commercial boating activities.
The selected remedy was to excavate or dredge the contaminated soils, then
remove 97 percent of the PCBs and dispose of the resultant soils in an on-site
vault. Innovative technologies were required to remove the PCBs from the soils
since, at the time of the ROD, incineration was the only method used for
treatment of PCB contaminated soils. Solvent extraction and thermal desorption
were considered. The SoilTech A TP Technology thermal desorber was selected.
Even though SoilTech had not been applied commercially and, in fact, a
commercial transportable unit did not exist, the technology was well advanced
with operating pilot units of similar size to the planned transportable unit. ;
Canonie agreed to a lump-sum contract to perform the excavation and dredging
and to treat the estimated 19,000 tons of material by thermal desorption using
the SoilTech A TP Technology. On the basis of this contract, the transportable
unit was manufactured at a cost of more than $5 million, to be immediately sent
to the Waukegan site to process the soils.
A provision was included in the work plan at the insistence of the agencies that
stack emissions had to meet "six-nines" Destruction Removal Efficiency (DRE) for
PCBs, a requirement that was not applicable to this technqlogy {but one the
agencies felt comfortable with) because the SoilTech ATP Unit did not destroy
PCBs and the emissions volume was orders of magnitude below that of an
incinerator. However, the agencies were adamant and the developer/vender of
the technology had little choice but to accept this stipulation in the work plan if
the project was going to progress. There were some indications from bench-scale
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work that this could be achieved and, if it was close, the developer/vender
assumed that the agencies would be reasonable, given the difference between
this technology and the incineration technology for which the criterion was
established. •••••- '••'-:/•"»'^h-^^:-*:-••;,-'•• •K^y^^--^"^- ••••: -, ..i^xA-,^^..,.,
Within the first few days of excavation at the s/te; unanticipated PAH-
contaminated soils were discovered and the whole project was stopped so the
agencies could determine what to do. The resultant delays lasted for well over
two years. Meanwhile, the technology developer/vendor was sitting with a $5
million piece of equipment having to pay debt service with no income.
Notification of delays were given to the owner and delay claims are being
discussed, but this did not help the technology developer with the difficult
financial conditions caused by the delay. Eventually, when the extent of the
delay was finally clear, SoitTech was able to find another interim project, but not
without unanticipated costs and interruptions in the overall commercialization plan
for the technology. Without strong financial backing, this initial perturbation
could have resulted in the end of this technology's commercialization.
Eventually the Waukegan project was once again under way. The SoilTech ATP
Unit was mobilized to the site, test work was done and production level
processing began. The soil types and water content were ideal for the unit and
production progressed at rates near the name plate capacity. The soils clean-up
criterion was near 500 ppm PCB. The cleaned soils had levels of less than 4 ppm
maximum and often were non-detectable. The project was going to be a
technical, schedule and financial success, when the agencies again brought the
whole process to a halt for failure of the A TP Unit to demonstrate the requisite
ORE of 99.9999 percent after repeated tests (the ATP was demonstrating
99.9996 percent ORE).
Risk assessments conducted by EPA indicated that the health risk at the boundary
of the site was less that Iff9, a level two orders of magnitude below requirements
cited in the Site Health and Safety P/an. The owner's experts determined that the
amount of natural volatization ofPCBs from stockpiled waste awaiting processing
in the ATP would exceed the mass of emissions that would result from
completing the project with a demonstrated ORE of 99.9996 percent The site's
citizens advisory committee was appraised of the situation and voted to
recommend completion of the SoilTech portion of the project since, at the time
of shutdown, more than 50 percent of the contaminated material had been
treated. ' " ' -
Case Study #4 (Continued) - Waukegan Harbor Superfund Site
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Faced with these arguments, EPA allowed the project to restart and proceed to
completion. However, it choose the lengthy administrative remedy of modifying
the Consent Decree to relax the emissions standard to 99.999 percent DRE. TJhis
required agreement on the part of the owner, the State\,ot[MicJifgan and the
Department of Justice. '" """ '' S:f:^;S::i::<; S^^fe^SK'^^i!:^?^'^!-^^:
The decision to relax the emissions standard was a difficult one for the EPA
Region as this Region has a commendable track record of successful pollution
control by imposing strict "technology-based" standards and, in the 1970s
established the knowledge base within EPA that allowed EPA to promulgate
nationallyenforceable Best Available TechnologyEconomically'Achievable effluent
guidelines for industrial discharges under the National Pollutant Discharge
Elimination System (NPDES) program in the early 1980s. However, the
administrative remedy of modifying the Consent Decree proved to be more
complicated and time consuming than anticipated.
During the negotiation process, however, the equipment and labor were sitting
idle. Frantic efforts were underway by the on-site crews supported by technical
staff in an attempt to make the equipment meet the criterion so operations could
continue. Carbon beds were added, dehalogenation agents were tried and other
near-research-level attempts were incorporated. None of these efforts improved
the performance of the unit to clean the soils, added to public health or
environmental protection or in any way helped the remediation of the project.
Finally, approximately two months after the processing was halted and before the
criterion change process could be culminated, the developer demonstrated a DRE
of 99.99999 percent, accomplished in cooperation with the Region and EPA's
Risk Reduction Laboratory in Cincinnati, Ohio, by additions and adjustments to
the equipment and plugging a hole in the carbon bed that had remained
undetected during previous attempts at improving air emission controls.
The cost to the developer/vender was, however, over $500,000, the remediation
of the site gained nothing, and the developer/vendor missed a window of
opportunity for another project.
Case Study #4 (Continued) - Waukegan Harbor Superfund Site
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Case Study #5 - San Jose Superfund Site
The development and application of a commercial-level Accelerated''Vacuum'.
Extraction System at the San Jose Superfund Site is a good example of the way
an innovative technology can be effectively commercialized by risk sharing among
all parties involved. •
The San Jose Superfund site resulted from leakage of an underground tank
containing waste so/vents. The so/vents reached the underlying drinking water
aquifers and caused significant concern. The remediation was accomplished in
a classic example of the Sequential Risk Mitigation approach advocated by
Canonie including pump and treat, source removal, containment with a slurry wall
and contaminated soils remediation. The use of the Accelerated Vacuum
Extraction System was part of the on-site soils remediation.
At the time of the soils remediation requirement, the owner of the property had
accomplished much of the remediation through the sequential application of
several different innovative technologies and approaches. The remaining
contamination was concentrated in the vadosezone of the on-site soils. The site
was sufficiently remediated that prospective buyers were interested in the
property. However, the property could not be sold with the soils contamination
remaining at levels above those considered acceptable to the agencies.
Canonie assessed the situation and presented two options to the owner.
1. Regular Vacuum Extraction using many wells pumped at low rates with
small pumps. This was the system most were using at the time to
accomplish soils aeration. The capital cost was low; however, the time to
remediation could be long and somewhat unpredictable, and the operation
and maintenance costs could be high.
.' •-.••:.'•.. f <• V^
: ' ' " 4
2. Accelerated Vacuum Extraction consisting of an innovative system
designed by Canonie to accomplish acceptable levels in the soils in a time
frame consistent with the impending sale and development of the property.
The capital costs were higher, but if the system performed as predicted,
the overall costs would be lower diie to the tower operation and
maintenance costs. The system was, however, unproven at commercial
levels.
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Canonie worked with the agencies to establish turn-off criteria for both systems
based on realistic anticipation of the performance of the respective technologies.
The accelerated system was more difficult to discuss since the agencies had not
seen such a system perform.
The owner elected to go with the accelerated system and worked with Canonie
on its development and application. The owner shared in the financial risk and
in the risk that the system might not perform as predicted. The agencies shared
in the risk by not imposing unrealistic operating performance criteria and agreeing
to reasonable shut-off criteria. •
The system was built and installed. The performance was near that projected.
The chemicals were removed from the ground on a schedule almost identical to
that predicted. The site was remediated and ready for sale at the time indicated.
The cooperation of all parties for this application of an innovative technology was
excellent. The developer was not financially burdened nor did he receive windfall
profits. The owner received remediation at a lower overall cost than with a more
conventional system. Since the owner also paid for the equipment, it was
available to do another project for the owner at no additional capital. The
agencies were able to show a site remediated in a timely manner. The project
was a success to all concerned because of the cooperative risk sharing of all
parties involved.
Case Study #5 (Continued) - San Jose Superfund Site
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PROPOSAL TO EPA
Canonie's experience at commercializing innovative hazardous waste treatment
technologies as depicted above represents considerable technical success, but not
always financial success. Ultimately, the viability and credibility of the hazardous
waste remediation industry (including regulators and regulated alike) will depend upon
two interrelated issues, financial success of those whom we rely upon to develop and
commercialize technologies and a regulatory approach which will foster cleanup of
hazardous waste sites quicker, cheaper and in a manner that will minimize risks and
liability for generators and site owners.
In response to this need, Canonie has made an unsolicited written proposal to EPA
entitled, "Accelerating Superfund from the Remediation Contractors' Perspective."
The precepts of this proposal as they relate to commercialization of innovative
technologies are:
1.
The selection of hazardous waste treatment technologies should be
made on the basis of reducing risk on a sequential basis by tackling the
parts of the problem that pose the greatest overall risk to the public first.
In doing this, a site should be viewed in a holistic sense and the arbitrary
distinction made by the current regulatory structure of "operable units"
be eliminated.
2.
Hazardous waste treatment technologies should be selected only
according to a realistic expectation that they can remediate a waste to
a certain level of clean-up.
3. Once selected, the technology should be allowed to operate without
microscopic regulation, provided the off-site public is protected and the
on-site conditions do not worsen.
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4. The marketplace will foster the development of innovative technologies
whose performance capability continues to improve simply because of
the desire of site owners and contractors to limit liability and risks.
The following summarizes Canonie's recommendations to EPA.
Sequential Risk Mitigation
Sequential Risk Mitigation as depicted on Figures 1 and 2 is a comprehensive and
structured approach to investigating, engineering and remediating complex hazardous
waste sites utilizing the "observational approach" to construction. Selection of
remedial actions and technologies is made in a sequential fashion (see example shown
in Figure 3) according to five levels of probable range of risk or status of
contamination that are estimated for the site (described in Figure 2).
Employing a repetitive approach of "investigate," "select," "implement," and
"observe," sites are remediated in a sequential fashion without much of the ritual (and
attendant "transaction" costs) of the RI/FS and remedial design phases of the current
Superfund program (or their RCRA equivalents). Knowledge obtained by observing the
effects of previous levels of remediation activity serves as the basis to select the next
remedial actions and technologies appropriate to the next desired level of cleanup.
The role of risk assessment in the Sequential Risk Mitigation model is significantly
different than that currently promulgated by EPA. We recommend that traditional risk
assessment methodologies to determine long term cleanup goals be deferred until the
site reaches Level IV. Canonie's proposed use of risk assessment is much more
truncated as it is designed for a different purpose, to determine the probable "range
of risk" that a site represents or would represent without intervention. This "range of
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risk" serves only as a bench-mark to determine the appropriate remediation strategy
and to measure progress as the site passes through various phases (levels) of
remediation.
Because sites are approached holistically, and interim goals for remediation are the
subject of remedial actions (not 100 percent solutions based on studies of operable
units), innovative approaches will be fostered.
Emissions Control During Construction
To address the central question of health protection during the operation of on-site
technologies, each site should be viewed as an "envirosphere" as depicted on
Figure 4. This figure shows various sources of emissions that can be predicted to
occur at the site during the remediation phase. EPA would establish a "Boundary
Condition" for the contaminants of concern, based on an acceptable level of the
temporary risk involved. The "Boundary Condition concept" is illustrated in Figure 5.
The site owner and/or remediation contractor would develop a "Site Emissions Control
Plan" (SECP). Methodologies for estimating and modeling emissions would be EPA-
approved.
Project construction would be allowed to proceed without interruption, provided site
boundary conditions are not exceeded. Treatment technologies could be operated in
a flexible manner.
In addition to the boundary conditions monitored for health protection during
construction activities, the policy framework would adopt a "technology-based"
component which would assure that the selected separation/treatment remediation
technologies perform to their maximum efficiency under site conditions. The
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RURAL AREA
URBAN AREA
FIGURE 4
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BOUNDARY
WASTE WATER
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DISPOSAL OF
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determination of "Best Technical Performance" would be made during the "proof-of-
process" phase based upon a "Proof-of-Process Plan" prepared by the
owner/contractor during the RD phase.
Together, the Boundary Condition and Best Technical Performance components form
a policy framework for establishing emissions performance standards which can be
characterized as the "Best Technical Performance That is Health Protective."
We view the combining of both health- and technology-based considerations as critical
to address concerns of the public regarding health protectiveness. The EPA is also
assured that the primary treatment/separation technologies achieve a greater degree
of emissions control efficiency than would otherwise be allowed on the basis of
human health. If the proof-of-process phase is extended to determine the best
technical performance on the contaminated medium as well as residual air emissions,
remediation to levels below the action limit established in the ROD represents a factor
of safety against future liability.
Summary
In summary, the following rules should apply to the selection and operation of
innovative technologies and approaches toward more cost-effective site remediation:
Selection of Technologies for Remediation
1.
Investigation of sites should be limited to gathering that only information
needed to select an RA to reduce the health risk from one level to the
next.
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2. An RA technology should be selected based on the health risk level of
the site and the ability of that technology to reduce the health risk by at
least one level.
3. Observation should be made during the implementation of an RA to allow
realistic, pertinent, cost-effective selection of an RA to take the site to
the next lower level of health risk.
Operation Constraints
1. A health- and risk-based boundary condition, which is determined by the
EPA, should be established for the site.
2. Exceedance of the boundary condition would result in the shut-down of
operation of the separation/treatment technology.
3. On-site proof-of-process testing should be the basis for determining the
best technical performance of the technology on site wastes. Operating
parameters and emissions limits will be established at this time to assure
the technology will perform to its capability, even when the resulting
emissions are more protective than allowed under the health-based
boundary condition.
5.
Continuous operation of the separation/treatment technology should be
allowed, provided proof-of-process testing demonstrates that boundary
conditions are not exceeded.
In the event that emissions limits or specified operating conditions are
exceeded following proof-of-process testing, but the boundary conditions
are not exceeded, the owner/contractor should be provided a reasonable
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response time to return the operation of the technology to a state of
compliance without interrupting the operation. The EPA-approved SECP
would define contingency actions and time frames.
6. EPA should not take enforcement action against the owner for failure to
meet emissions limits or operating conditions provided that the failure did
not arise from knowing endangerment or willful misconduct.
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CONTRACTUAL MECHANISMS TO SHARE RISK
Contractual methods of risk sharing are imperative and feasible for application of
innovative technologies. The totally successful projects discussed above utilized such
types of contracting methods.
Unlike standard well-defined construction projects, lump sum or fixed unit prices are
often not good contracting methods for applying innovative technologies. Such
contracts assign financial risk to the innovative technology contractor. Many such
contractors cannot define the magnitude of that financial risk and consequently
cannot bid the work or must add such levels of contingency that their technology
looks unattractive.
Contract methods more suited to innovative technologies include target-valve-
incentive, daily-rate-cost reimbursement or time-and-materials cost reimbursement
contracts with not-to-exceed limits. These contract types give incentives to the
contractors to make their technology perform, yet limit their financial exposure.
Contractors should not, however, be given "blank checks." Checks and balances are
required. A technology can receive a bad reputation and not be selected on future
jobs if significant cost overruns occur on cost-reimbursable type contracts. This can
be as detrimental to the technology's future as significant financial distress to the
innovative technology contractor on fixed price contracts.
Cooperation in developing an appropriate contract should be part of this plan, but all
parties must be good business people. A "win-win" situation can be established
whereby technical success is coupled with financial success for both the contractor
and the owner.
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CONCLUSION
Cost-effective development and commercialization of innovative waste treatment
technologies to remediate hazardous wastes can be fostered by a more cooperative
spirit on the part of regulators, owners and vendors with each making a concerted
effort to understand the goals and constraints of the other and a willingness to share
the risk, and a change in mind-set in planning, designing and physically cleaning up
contaminated sites. The regulatory decision process needs to be redefined to allow
innovative technologies to be selected on the basis of a realistic expectation of
performance to a specified level of cleanup. Sequential Risk Mitigation incorporates
the observational approach to construction wherein remedial actions are selected to
address the most serious health risk first, with subsequent levels of cleanup defined
on the basis of observations and experience obtained in the previous stages of
construction.
Once construction is under way, the contractors and vendors must be allowed to
modify operations to adjust to changing site and waste conditions encountered
without microscopic regulation, interruption of operations of the technology and
without fear of enforcement provided that the adjacent public health is protected.
Canonie's proposals for "Sequential Risk Mitigation" and the decision model for
residual waste emissions control during construction can be implemented within the
current Superfund statutory and policy framework. If adopted, transactional costs will
be reduced and the 80/20 rule applied - eighty percent of the problem solved at
twenty percent of the cost.
Without a comprehensive revamping of the regulatory approach along the lines
suggested herein and in Canonie's report to EPA entitled "Accelerating Superfund
from the Remediation Contractors Perspective," more cost-effective innovative
technologies will not be developed and applied on a wide scale.
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PREPRINT EXTENDED ABSTRACT
PRESENTED AT THE U.S. EPA FOURTH FORUM
ON INNOVATIVE HAZARDOUS WASTE TREATMENT TECHNOLOGIES-
DOMESTIC & INTERNATIONAL
SAN FRANCISCO, CALIFORNIA, NOVEMBER 17-19, 1992
• . i. • '
BIOREMEDIATION OF CHROMIUM (VI) CONTAMINATED
SOLID RESIDUES USING SULFATE REDUCING BACTERIA
Louis J. DeFilippi, PhD, Allied-Signal Research and Technology. 50 E. Algonquin Rd.. Des
Plaines IL. 60017-5016 Tel (708) 391-3251: FAX (708) 391-3776
Cr(VI)-containing residues -are of concern when present in the environment.
Chromate [hexavalent chromium, Cr(VI)] is a strong oxidant and has toxic potential.
Dissolved Cr(VI) has a propensity to pass through mammalian cell membranes and, due to its
water solubility, also has the potential for groundwater migration. This material often arises
from the chromium roasting process, where chromium in iron-containing ore is oxidized to
chromates to enable separation of the water-soluble chrbmates from insoluble ferric oxide.
The residues from the aforementioned process contain Cr(VI) usually in a highly alkaline
environment arising from the presence of rather high levels of lime (CaO), which is used in
large quantities in the chromium ore roasting process. For example, water in contact with
solid waste arising from lime extraction of roasted chromium bearing ores possess a pH of
between 10 and 11. An extreme pH necessitates pH adjustment prior to microbiological
treatment, but this often leads to saline conditions that are not conducive to bacterial
proliferation.
The naturally occurring reduction of Cr(VI) to Cr(in) by hydrogen sulfide produced
by sedimentary sulfate reducing bacteria has been noted by R. H. Smillie, et al. (1).
However, until recently it was believed that sulfate-reducing bacteria were considered to be
unsuitable for treating chromium-containing industrial waste waters because of the inherent
toxicity of chromium to microorganisms.
We previously described a bioremediation system (2,3), based upon the generation of
H2S by sulfate reducing bacteria, to effectively reduce Cr(VI) present in saline aqueous
fractions to the low toxicity, low solubility state, Cr(ffl). We have no™ extended this
approach to include bioremediation of solid residues in contact with a liquid aqueous
fraction, especially when salinity is high. We feel the use of a sulfide intermediate to effect
bioremediation is superior to direct bacterial reduction for a number of reasons, especially
that H2S may "seek out" Cr(VI) by diffusing to microenvironments poorly accessible or
inhospitable to microorganisms or their nutrients. For lime-containing waste the process
involves the addition of a suitable acid, such as HC1, to effect a pH between 6.0 and 9.5,
followed by treatment with an acclimated, anaerobic sulfate reducing bacterial inoculum.
For example, 5.1 g tailings containing 950 ppm Cr(VI) and 16,000 ppm total Cr were
loosely packed into a 0.7 X 17 cm glass column and then treated (down-flow) with 1.5 mL 1
M HC1, then water, then the inoculum. A black layer (indicative of metal sulfides) 1 cm
thick formed at the surface while below an off white precipitate [indicative of Cr(OH)3] was
dispersed. Treatment continued until < 0.006 ppm Cr(VI) was detectable in the effluent. In
another experiment untreated solid residue exhibited 103 ppm TCLP extractable Cr(VI).
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After bioremediation this value dropped to < 0.0002.
We have field-tested a similar approach on a 2,000 gal/wk scale. In this particular
instance the pH of the groundwater was in the neutral range so that no pH adjustment of the
groundwater was necessary in situ. The heart of the bioremediation system was a 1,000 gal
fermenter. In it was fermented a solution of sodium sulfate, ammonium sulfate, super
phosphate and molasses dissolved in estuarine (brackish) water. The function of the
fermenter was to effect an acidogenic phase of the fermentation in a reactor where the pH
could be readily controlled. In it the molasses carbon source was fermented, and the initial
production of anaerobic, sulfate reducing bacteria and H2S-containing fermented broth
occurred. The balance of the metabolic process occurred in situ. During the acidogenic
stag* of the fermentation the pH of the broth dropped due to the formation of VFAs (volatile
fatty acids). The pH was maintained at about 8 tnrough the addition of soda ash (sodium
carbonate). Each batch of fermentation fluid was deemed to be ready for injection when the
pH of the broth ceased to change.
The fermented broth and bacteria were applied to two experimental plots, a
percolation site, which was designed for remediation of the Vadose zone through flooding of
that zone, and an injection site, designed for remediation of the water saturated zone. The
percolation site consisted of an open-bottomed box fitted with a lid and a Calgon H2S
scrubber that effected retention of fermentation broth over a specified area. It is one half of
a percolation and leachate recirculation option that is a potential system for contaminated soil
and groundwater remediation. The injection site consisted of a single injection well. Both
sites were surrounded by a number of piezometer (pipes) for groundwater monitoring.
We found that the bioremediation of Cr(VI) on site was successful within certain
limitations. Possibly the most critical factor in success is the geology of the site. Where
remediation was most complete, the conductivity properties of the soil or residue were
consistent with the presence of high conductivity and, therefore, preferential paths of flow.
Where there was lack of maintenance of anaerobic conditions of Vadose zone areas due to
rapid draining of fermented broth there was less than optimal reduction of Cr(VI).
We have performed cost estimates for the main raw materials used for the
bioremediation of lime-laden sites. By titration of existing surface residue we determined
that it would require about 4.3 mEquiv/g to attain a pH of 8. For a site containing
1,000,000 tons of residue this translates to 3.9 x 109 equivalents, and the same number of
moles of the monoprotic acid HC1. This is equivalent to 16,700 tons pure HC1 or 46,400
tons of 22° Be" (12 M HC1) material. At $68/ton this is $3.2 x 106. Waste acid is often
available for a considerably lower price.
The concentration of Cr(VI) is typically 3.5 g/kg, wet weight. Again, for a site
containing 1,000,000 tons of residue this translates to 6.1 x 107mol of Cr(VI). The
stoichiometry of the reduction of Cr(VI) [as CrO4=] to Cr(m) [as Cr(OH)3] is as follows:
2CrO<" + 3H2S + 2H2O — > 3S + 2Cr(OH)3 + 4OH'
thus requiring 9.2 X 107 mol H2S. Since H2S is generated from SO4= on a one to one molar
basis, an equivalent number of moles SO4" is needed. At $90/ton this is $1.3 x 106 plus
shipping. A portion of this cost is defrayed by the use of sulfate naturally present in sea or
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estuarine water.
The cost of the carbon source is quite variable. Waste molasses is possibly obtainable
at nearly shipping costs. Items such as "sugar water" are available free in the Industrial
Waste Exchange Program. When these are not available, com syrup, 43 Be", is available for
$11.22/100 Ibs. Although one mole of glucose is required for the production of three moles
sulfide, taking into account metabolic needs there is a requirement for 3.8 x 107 mol glucose.
At $0.20/lb this comes to $3 x 106. Capital costs at well as ongoing pumping and analytical
needs would be an additional factor.
(1) Smillie, R.H., Hunter, K. and Loutit, M., "Reduction of Chromium (VI) by BacteriaUy- ;
Produced Hydrogen Sulfide in a Marine Environment," Water Research, 15_, 1351 (1981).
(2) DeFilippi, L. J. and Lupton, F. S., Proceedings ofR&D92 National Research &
Development Conference on the Control of Hazardous Materials, San Francisco CA, pp. 138-
141, February 4-6, 1992.
(3) Lupton, F. S., DeFilippi, L. J., and Goodman, J. R., U.S. Patent 5,062,956 (1991).
*U.S.GOVERNMENT PRINTING OFFICE:! 99 3 -750 -002/60163
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