September 1987
PCS Sediment Decontamination
Processes—Selection for
Test and Evaluation
Project Summary
by
Ben H. Carpenter
Research Triangle Institute
Research Triangle Park, NC 27709
Contract No. 68-02-3992
RTI Project No. 471U-3065-65
Project Officers: Donald L. Wilson, T. David Ferguson
Hazardous Waste Environmental Research Laboratory
Cincinnati, OH 45268
Hazardous Waste Engineering Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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PROJECT SUMMARY
PCB SEDIMENT DECONTAMINATION PROCESSES -
SELECTION FOR TEST AND EVALUATION
by
Ben H. Carpenter
Research Triangle Institute
Research Triangle Park, NC 27709
Contract No.: 68-02-3992
RTI Project No.: 471U-306S-65
Project Officers: Donald L. Wilson
and
T. David Ferguson
Hazardous Waste Engineering Research Laboratory
Cincinnati. OH 45268
Hazardous Waste Engineering Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati. OH 45268
September 1987
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PROJECT SUMMARY
PCS SEDIMENT DECONTAMINATION PROCESSES -
SELECTION FOR TEST AND EVALUATION
Ben H. Carpenter
ABSTRACT
Eight alternative treatments for PCB-contaminated sediments have been
assessed as candidates for immediate thorough test and evaluation. The proc-
esses are: Basic Extraction Sludge Treatment (B.E.S.T), UV/Ozone or Hydrogen/
Ultrasonics Technology, Bio-Clean Naturally-Adapted Microbe. Potassium Poly-
ethylene Glycolate (KPEG). Low Energy Extraction, MODAR Supercritical Water
Oxidation, Critical Fluid Systems (CFS) Propane Extraction, and Battelle In
Situ Vitrification.
The processes were evaluated using five criteria: the probability of
cleaning sediments to 2 ppm or less; the availability of a teat system; the
test and evaluation effort required; the time required for future availability
of a commercial treatment process; and the probable cost of treatment using
t process. These criteria were addressed by engineering analysis of avail-
e data and site visits to developers' facilities.
The processes were ranked comparatively as to the overall desirability of
thorough test and evaluation using all five criteria collectively. Two rating
methods were applied: a multiplicative model using a Desirability Function
and a linear model, d-SSYS, using weighted utility functions. Both methods
converted the process characteristics to ratings on a scale from 0 to 1 (worst
to best). The Desirability approach normalized the characteristic using the
difference between acceptable and borderline values; d-SSYS normalized the
characteristic using the difference between the maximum and minimum values.
In calculating the overall score, the factors were weighted equally in the
Desirability Function. Probable cost of treatment and test and evaluation
effort were assigned weights 4 to 5 times those of the other three character-
istics in the d-SSYS ranking. These Independent approaches gave final overall
desirability scores as follows:
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Desirability d-SSYS
Process score score
Kale Extraction Sludge Treatment, 0.623 0.8127
Resources Conservation Conpany
UV/Ozone or Hydrogen/Ultrasonics Treatment. 0.621 0.8010
Ozonic Technology, Inc.
Naturally-Adapted Microbes Process, 0.617 0.7583
Bio-Clean. Inc.
Potassium Polyethylene Glycolate (KPEG), 0.615 0.7434
Galson Research, Corp.
Low Energy Extraction. New York University 0.614 0.4529
Supercritical Water Oxidation. NODAR. Inc. 0.600 0.4738
Propane Extraction Process. 0.590 0.6214
Critical Fluid Systems
In Situ Vitrification. Battelle 0.460 0.2299
While all the processes except In Situ Vitrification appear to merit
further development for this application, those three with the highest compar-
ative ratings are recommended for immediate EPA-supported thorough test and
evaluation. These are the Basic Extraction Sludge Treatment, UV/Ozone or
Hydrogen/Ultrasonics Technology, and Bio-Clean Naturally-Adapted Microbe proc-
esses .
This recommendation does not mean that the other processes merit no fur-
Ber T and E. The Potassium Polyethylene Glycolate (Galson), Low Energy
Extraction (New York University), MODAR Supercritical Water Oxidation, and
Critical Fluid Systems Propane Extraction processes rank very close to the top
three. Thus these seven processes merit consideration for testing at least
through the preliminary phases to confirm their performances.
This project summary was developed by EPA's Hazardous Waste Engineering
Research Laboratory, Cincinnati. Ohio, to announce key findings of the
research project that is fully documented in a separate report of the same
title (see Project Report ordering information at back).
INTRODUCTION
The PCB-contaminated sediment problems in New Bedford. Massachusetts (EPA
Region I) in New York State (EPA Region II) and In Waukegan. Illinois (EPA
Region V) are reported to be the worst in the nation In terms of PCB concen-
tration and the total quantity of PCBs present. In addition, there are
numerous industrial lagoons with large quantities of PCB contaminated sedi-
ments. PCB contamination poses threats to both drinking water and the fishing
istry.
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The only available proven treatment technology Is dredging and expensive
J neration. Land disposal of the sediments untreated has legal restric-
B. The Environmental Protection Agency (EPA) has initiated a three-phase
research program to identify, validate, and demonstrate effective and economi-
cal chemical/biological processes for the removal/destruction of PCBs in sedi-
ments. The Phase 1 study screened 64 emerging process technologies and
selected eleven for evaluation: Potassium Polyethylene Glycolate with
Dimethyl Sulfoxide (Galson Research Corporation); O.H.N. Methanol Extraction;
Advanced Electric Reactor (J.M Huber Corporation); Acurex Solvent Wash
(Electric Power Research Institute); Bio-Clean Naturally-Adapted Microbe (Bio-
Clean. Inc.); Battelle In Situ Vitrification; Light Activated Reduction of
Chemicals ((LARC). Atlantic Research Corporation); MODAR Supercritical Water
Oxidation: Sollex Solvent Extraction; Sybron Bl-Chem 1006B; and Composting (as
studied by the Atlantic Research Corporation) (Carpenter. 1987). The evalu-
ation showed the first eight of these to have potential for reduction of PCB
concentrations to the desired background levels or less, with minimal environ-
mental impacts and low to moderate coat. All of the eight except the Advanced
Electric Reactor required further development and testing.
Phase 2 study was undertaken to establish suitable factors for fur-
assessment of candidate processes, to identify additional data needs, and
provide a basis for selection of three processes for a defensible, thorough
technical assessment, including laboratory experiemnts and field evaluation.
The study involved consultations with treatment process developers, technical
assessment of the processes, and the selection of the three highest ranking
processes for immediate teat and evaluation.
SCREENING OF CANDIDATE PROCESSES
The seven candidate processes that required further development and test-
Ing were screened at the start of this Phase 2 (Validation) study for avail-
ability of a continuing developer and a treatment system for use in test and
evaluation of the process. The results of this screening are given in Table
1. Three processes were eliminated from further consideration. The Solvent
Wash process is not available for assessment because its sponsor, the Electric
Power Research Institute, is seeking a firm to undertake the further needed
development of the process before it is ready for further consideration. The
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Process
TABLE 1. INITIAL SCREE '• OF TREATMENT PROCESSES
Contact
Continuing
Developer
Test Systeem)
Available
KPEG
OHM Extraction
EPRI Solvent Hash8
Battelle Vitrification
Bio-Clean. Inc.
NOOAR Supercritical Mater
Dr. Robert L. Peterson Yes
Galson Research Corporation
6601 Klrkvllle Road
Bast Syracuse, NY 13057
Sue Maaon No
OH Materials
16406 U.S. Rt. 224 E.
Plndlay, OH 45839-0551
(419) 423-3526
Ms. Mary McLearn No
Electric Power Research Institute
3412 HlllvleN Avenue
Palo Alto, CA 94304
Craig TlMeraan
Battelle Pacific Northwest Laboratory Yes
P. 0. Box 999
Rlchland, HA 99352
Dr. Lance B. Croable, Yes
Director of Labs
201 H. Burnsvllle Prkwy., Suite 130G
Burnsvllle. MN 65337
(612) 890-1118
Ralph A. Morgan Yes
Modar, Inc.
3200 Wllcrest, Suite 220
Houston, TX 77042
(713) 785-5615
Yes
No
No
Yes
Yes
Yes
(Continued)
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Process
TABLE 1
Continued)
Contact
Continuing
Developer
Test Syste*(s)
Available
LARC
Basic Extraction Sludge
Treatment
CP Systeas Propane
Extraction
Ultrasonics/UV Technology
Low Energy Extraction
Process
George Anspach
Atlantic Research Corporation
5390 Cherokee Avenue
Alexandria, VA 22312
Mark lose
Resources Conservation Co.
3101 N.E. Northup Hay
Bellevlew, HA 08004
(208) 828-2376
Thomas J. Cody, Jr.
CP Systems Corporation
25 Acorn Park
Cambridge MA 02140
(817) 402-1631
Edward A. Pedzy
Ozonic Technology, Inc.
90 Herbert Avenue
P. 0. Box 320
Closter, NJ 07624
(201) 767-1225
Halter Brenner/Barry Rugg
New York University
Dept. of Applied Science
26-36 Stuyvesant Street
New York. NY 10003
(212) 508-2471
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Planned
aThis process was identified as the Acurex process in the Phase 1 study.
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developer of the OHM Extraction process has chosen not to invest In this proc-
Is. The developer of the LARC process has not identified sufficient Markets
d the process is not available from the*.
Meanwhile, four technologies not assessed in the Phase 1 study have become
available: the Basic Extraction Sludge Treatment (B.E.S.T.) process
(Resources Conservation Company); the Critical Fluids Systems Propane Extrac-
tion process; the (JV/Ozone or Hydrogen/Ultrasonics process (Ozonic Technology.
Inc.); and the Low Energy Extraction process (New York University). These
have all been assessed as candidates for thorough test and evaluation. The
UV/Ozone or Hydrogen/Ultrasonics Technology provides continuity for the
radiant-energy approach previously represented by the LARC process. The other
three processes provide improved approaches to the extraction technology. The
results of Initial screening of these processes are also given in Table 1.
DESCRIPTIONS OP TREATMENT PROCESSES
The Basic Extraction Sludge Treatment process pretreats the feed (sedi-
ment, sludge, oily contaminants, water) with an alkaline composition, then
admixes with triethylamine (TEA) while cooling below the critical solution
temperature (U.S. Patents 3899410. 3925201. 4002562. 40S6466). A single
Huld phase is formed from which the solid matter is separated. The liquid
is then heated to above the critical solution temperature to form an amlne-
rich phase and a water-rich phase, after which the water phase is decanted.
The amine phase contains all of the oil contaminants. It is processed to
recover the oil and contaminants, and the TEA is recycled for the processing
of additional material.
The UV/Ozone or Hydrogen/Ultrasonics Technology Involves three factors,
all of which have been shown to be effective. The UV/Ozone technology has
been demonstrated for destroying PCBs in industrial waste waters (Arisman et
al.. 1981). PCBs have been extracted from soils using Tween 80 surfactant
(Scholz and Mllanowski. 1984). They have been removed from metallic surfaces
using surfactants and ultrasonics (Smith and Sltabkhan. 1986). UV/Hydrogen
has been shown to destroy PCBs in non-aqueous solvents (Kitchens et al., 1979,
1984). Ozonics Technology. Inc. Is equipped to apply all three factors in a
comparative evaluation of ozone vs hydrogen.
The Bio-Clean process utilizes selected naturally adapted microbes to
destroy PCBs under aerobic conditions. Contaminated sediment is charged as a
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water slurry to a digester. The charge is adjusted to optlaua pH and heated
^a extract the PCBs. Surfactants May be added to promote extraction. After
Brcraction, the slurry is cooled, neutralized, and inoculated. The PCBs are
degraded in from 48 to 72 hours depending on the process conditions and the
•icrobes employed (Bio-Clean. Inc.. 1985) (Crombie, 1986, 1987) (Unteraan,
1985).
The Potassium Polyethylene Glycolate process degrades PCBs by nucleophlllc
substitution. An equal volume of contaainated sediment and reagent are blend-
ed in a reactor, and heated to remove excess water and promote the reaction.
The Galson version of the process promotes extraction of PCBs with dimethyl
sulfoxide (Peterson, 1986). The treated sediment is settled, the reagent
removed by decantation, and the solids are washed with water (Research Demon-
stration Permit Application, 1987).
The Low Energy Extraction process Involves separation of water from the
sediments, a solvent leaching with a hydrophylic solvent (e.g. acetone)
usually carried out in countercurrent stages, and transfer of the leached
organic contaminants to a hydrophobia solvent (e.g. kerosene) in which it Is
concentrated for final destructive treatment. The final treatment is a
«rate process. Residual contaminants in the water stream are adsorbed onto
ntaminated sediments. The system recycles all solvents and returns only
decontaminated sediments and water to the environment (Brenner et al., 1986).
The MODAR Supercritical Water Oxidation process feeds a water slurry of
contaminated sediments together with liquid oxygen to a pipe reactor where, at
400-600 *C and 22-25 MPa, the contaminants dissolve and react rapidly with the
oxygen. The reactor effluent is cooled by heat exchange with fresh feed.
Pressure let down and separation of sediments, liquid, and gases is carried
out in multiple stages to minimize erosion of valves and optimize equilibria
(Staszak et al.. 1987).
The Critical Fluid System Propane Extraction process uses propane at ambi-
ent temperature and 1.8 MPa (200 lb/in2) to extract PCBs along with other oily
organlcs from a water slurry of the sediment. The batch extraction is repeat-
ed as required to achieve specified reductions in contaminants. The treated
slurry is discharged after separation from the liquid propane which contains
the dissolved contaminants. The propane solution is fed to a separator where
the solvent is removed by vaporization and recycled. The contaminants are
off for final treatment in a separate process.
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The Battelle In Situ Vitrification process was developed to stabilize
fdionucllde-contamlnated soils by melting into a durable glass and crystal-
ne fora (Buelt et al.. 1987). Submerged sediments are dredged and relocated
for treatment. Four electrodes are Inserted into the sediments in a square
array. A path for electric current is made by placing a mixture of graphite
and glass frit between the electrodes. Dissipation of power through the
starter materials creates temperatures high enough to melt a layer of sedi-
ments, which establishes a conductive path. The molten zone grows downward
through the contaminated soil. At the high temperatures created (> 1700 *C)
organic materials pyrolyze, diffuse to the surface, and combust. Off-gases
are collected, monitored, and treated (Tlmmerman, 1986).
DEVELOPMENT OF EVALUATION CRITERIA
The following criteria -were used to select treatment processes for
thorough test and evaluation:
1. The likelihood that the process will acceptably clean up the PCB-
contaminated sediments;
2. The probable cost of the application of the treatment after perform-
ance is proven:
3. The relative level of T and E effort to be supported by the
Environmental Protection Agency;
4. The availability of a processing system to test; and
5. The likely future commercial availability of the process.
The standard selected for acceptable cleanup is a PCB concentration in
treated sediments (or soils) of 2 ppm or less.
EPA has considered PCB requirements preparatory to their promulgation as
an amendment to the PCB regulations (40 CFR, Part 781, April 2, 1987, pp.
10688-10710). The proposed standards require cleanup as follows.
1. Nonrestricted area — <, 10 ppm plus 10" cap of soil £ 1 ppm.
2. Restricted area — 25 ppm.
3. Outdoor electrical substation — 25 ppm, or 50 if a warning sign is
maintained.
These standards would apply to PCB spills occurring after promulgation.
occurring earlier, and spills which are apt to result in spread of
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PCS's into other media (groundwater, surface waters, grazing landa. and
Ketable gardens) are to be decontaminated to requirements established at the
cretlon of the EPA regional officer.
These levels (10 ppm. 25 ppm, and SO ppm) are to be attained by removing
all contaminated soil exceeding these levels. The removed soil Is subject to
disposal regulations: cleanup to <2 ppm. For this reason, permits issued for
alternative destruction processes generally will require that all treated
materials and by-product waste streams must have PCB concentrations of less
than 2 ug/g resolvable chromatographic peak (2 ppm). If this condition is not
met, the effluents containing 2 ppm or greater must be disposed as if they
contained the PCB concentration of the original Influent material. If the PCB
feed material being treated by the process is over 50 ppm PCB, then the
resulting effluents must be incinerated unless an analysis is conducted and
indicates that the PCB concentration is below 2 ppm per PCB peak.
In accordance with these policy and treatments requirements, the cleanup
target for alternative treatments has been set at <2 ppm PCB.
The probable cost of treatment Is presented as the cost per cubic meter of
sediment treated, based on a system sufficiently large to process 380,000 m3
« Hudson River sediments in 2.5 years. By focusing on a specific site and
e of cleanup task, each process could be assessed using available data from
sampling and analyses to characterize the feed materials to the processes, and
comparative cost estimates for a specific application could be obtained. The
sediments from the Hudson River present a variety of sediment types for test-
ing PCB-treatment processes.
The probable cost of treatment was obtained from the developers for those
processes sufficiently supported by commercial firms, or was estimated using
as major cost elements capital costs, and operation and maintenance costs.
Treatment process requirements determined capital, energy, and maintenance
costs. Labor rates, overhead, contingency, profit, and health and safety were
costed using standard unit values for all the processes.
Since no full-scale systems exist for the processes under assessment.
capital costs were estimated by designing a full-scale system, utilizing the
data available as a basis. Equipment costs were then obtained as budget esti-
mates from manufacturers or developers, or estimated using the method of
exponents:
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Cf - Cj (Qi/Q!)n
where: Cj - coat for ith capacity (size);
Qj - itn capacity;
n - empirical constant;
Cj - cost of reference capacity; and
Ql - reference capacity.
Values for the reference capital cost and the exponent, n, were obtained
in part from the literature and In part from equipment manufacturers.
Labor hours were estimated based on an automated industrial chemical proc-
essing plant (Peters and Tlmmerhaus, 1980):
e2 - «i (Q2/Ql)n
where: ej - Operator hours per day and processing step of reference case:
62 • Operator hours per day and processing step of case 2;
Qj - Process capacity of reference case;
Q2 - Process capacity of case 2; and
n • Empirical constant.
The values used in this evaluation are: ej - 18 h/d x step;
Q! - 9.07 mt/d
n - 0.22
The number of foremen and chemists are taken to be 15 percent of the num-
ber of operators. In addition to these workers, there is one site manager.
The hourly wages are assumed to be: Operators: 15 $/hr
Foreman: 18 $/hr
Chemist: 25 $/hr
Manager: 60 $/hr
Maintenance was estimated at 10 to 15 percent of the capital cost, depend-
ing on the number of unit operations Involved and engineering practices for
the operation. The allowance for safety equipment was generally $0.30/»3 of
sediment treated ($114.000 for the cleanup of 380,000 m3 of sediment).
10
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The treatment system cost estimate was capitalized (recovered) over the
K years of operation taken as the base period. Some developers provided
atment costs that were correspondingly lower for subsequent applications.
The test and evaluation effort required was estimated based on a compari-
son of available process data with the requirements for thorough test and
evaluation. The following information must be provided to qualify a process
for a permit to test:
1. Waste characteristics;
2. Process engineering description;
3. Sampling and monitoring plan;
4. Accident and spill prevention and countermeasure; and
5. Demonstration test plan.
For these assessments, Hudson River sediments were selected as the character-
ized wastes.
Hudson River sediment samples have been classified according to their con-
tent of clay. silt. muck, muck and wood chips, sand, sand and wood chips,
«se sand, and coarse sand and wood chips (Tofflemire and Qulnn, 1979).
ments have been shown to range from clay to cobbles, with the largest mass
fraction being in the sand sizes.
The highest PCB concentration was in the muck with wood chips class, which
typically had over 30 percent silt and clay, high volatile solids and some
small but visible wood chips. The size lowest in PCB was medium sized sand or
gravel without wood chips.
The coarse fraction (>0.42 mm) of the sediments typically contained wood
chips, sawdust, shale chips, cinders, and coal fragments. The fine size frac-
tions contained some fragments of the above, plus sand (containing quartz and
feldspar), silt, clay, and organic material.
Process engineering descriptions were developed for each process assessed.
These varied in completeness because the processes varied in stage of develop-
ment from conceptual to field tested. While unit operations were identified
and described for all processes, the descriptions were based only on per-
formance requirements. Detailed equipment specifications have not been made.
except where necessary to obtain cost estimates (e.g., high pressure compres-
_fk| and slurry pumps).
11
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The descriptions included process flow diagrams and identified all product
K waste streams. Additional process information included summaries of bench
ts, pilot tests, and field tests, if available.
Sampling and monitoring plans were then developed, baaed on the scale of
process tests required, the purposes of the tests, and the extent of data
needed to characterize the process performance and scaleup the system to full-
scale. Some of the processes, when the developers' prior experience justifies
it, can be scaled-up from bench-scale teats. Thus, the size of system indi-
cated for test and evaluation (T and E) is the size the developer feels can be
scaled-up with confidence. For the needed testa, the extent of sampling and
analyses was indicated. Methods of analysis were specified. Prom the infor-
mation developed. T and E coats were estimated.
For most of the processes assessed, test systems are available from the
developer. Most developers would need financial support of the testing time
and effort. The availability of a suitable test system and any conditions/
restrictions on its use were considered for each process.
Accident and spill prevention and counter-measures needs have been identi-
fied. Part of the estimated treatment cost is allocated to these factors.
The processes vary as to the strength and extent of their sponsorship.
^He developers are commercial firms in the waate treatment business with
resources committed to further commercialization of their process. Some
developers have a need for financial support to achieve commercialization. In
all cases, the short-term (2.5 years) effort projected in this evaluation, and
the uncertainties of further markets make the construction of a full-scale
treatment system contingent upon completion of the T and E (with attendant EPA
approval of the process) followed by a contract for the cleanup work itself.
Under these necessary conditions, all the processes assessed would be commer-
cially available. The estimated time required to make them available varies
from process to process, however, and this has been taken into consideration
in this evaluation.
PROCESS EVALUATION
All the processes assessed have merit. In selecting among them, a ranking
system has been employed for comparative simultaneous evaluation of all five
criteria characteristics (Harrington, 1965). For each process, the
12
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desirability of immediate thorough test and evaluation was expressed by a
r ability value. Dj:
where: djj = the rating of process J for criteria i for 1 from l to 5,
0.0 < d <. 1.0.
This function is a multiplicative decision model . although it »ay be
regarded as a linear model if it is utilized in its logarithmic form. The
methodology does not in its original form provide for weighting of the factors
involved. Instead, it applies equal weights to all factors. Each factor may
be weighted, however, by the application of an appropriate exponent. This is
shown as follows:
0 - (d Xld
uj, modified valj a2j 3J "• nj
where: xj - the weight of factor i
The logarithmic form is:
(3)
U + X2 lo* d2J * X3 lo« d3J * ' ' ' * xn n
0 < d < 1
The value found for each characteristic, y. was transformed to a value of
d according to the following judgements:
Value of d
1.0-0.99 Represents the ultimate level of the characteristic y.
Improvement beyond this point would have no appreciable
value .
0.99-0.80 Acceptable and excellent. Unusually good performance.
0.80-0.63 Acceptable and good.
0.63-0.40 Acceptable. Some Improvement is desirable.
0.40-0.30 Borderline acceptability.
0.30-0.01 Unacceptable. This one characteristic could lead to
rejection of the process.
13
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The scale of d so developed is a dimensionless scale to which any charac-
Krlatic nay be transformed so that it »ay be Interpreted In terms of its
sirability for the intended application. In this evaluation, the most cost-
effective final process was sought that could be available in the shortest
reasonable time.
A characteristic assessed on a numerical scale was transformed to the
scale of "d" by the basic equation:
dl . e-e0.77941[(-yi + yn)/(ylh - yu)
In this equation: yj is a value of a treatment process characteristic 1;
is the acceptable valuable of yl; and
is the borderline value of y<.
(4)
Table 2 shows the acceptable and borderline values of yj for each charac-
teristic rated.
TABLE 2. ACCEPTABLE AND BORDERLINE VALUES FOR PROCESS
CHARACTERISTICS
Character i s 1 1 c
Probability of cleaning to £ 2 ppm
Probable cost of treatment. $/m3
T and E effort, S/1000
Test system availability, rating
Time to provide commercial system, months
Acceptable
Value*
0.9
100
300
0.9
IS
Borderline
Value b
0.3
300
900
0.3
36
ad « 0.63 for these values.
bd * 0.37 for these values.
The probability of cleaning to £ 2 ppm was set at 0.9 If such performance
had been demonstrated with soils of any type, 0.8 if such performance was
projected from test data, and 0.3 if no data were available. The use of 0.9
and 0.8 distinguishes slightly between processes reaching the goal of < 2 ppm
on initial tests and those for which reaching this goal could be projected
from initial teats.
The probable cost of treatment was considered acceptable if $100/n3, and
borderline if S300/m3.
T and E effort was considered acceptable up to $300,000. Values above
$900,000 were considered borderline, but could be justified if the process had
14
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potential for lowering the cost of treatment, or rated extremely well on other
fepired characteristics.
Test system availability was rated 0.9 for an available company-provided
system with experienced operating staff and resources to commercialize the
process; 0.8 if further government purchases were required to provide a
system; and 0.3 if a suitable test system were not available.
Time to provide a commercial system sized to effect cleanup of 152,000 m3
of sediment per year was considered acceptable at 18 months, but borderline if
36 months were required.
Using the values of the characteristics shown in Table 2, Equation 4 was
applied to calculate the individual ratings shown for each process in Table 3.
This table also shows the overall desirability rating of the process, calcu-
lated using Equation 1.
All the processes show acceptable "D" values. The Basic Extraction Sludge
Treatment, UV/Ozone or Hydrogen/Ultrasonics, and Bio-Clean Naturally-Adapted
Microbe processes show the highest values, and are recommended for immediate
test and evaluation.
This recommendation does not mean that the other processes merit no fur-
^fe* T and E. The Potassium Polyethylene Glycolate (Galson). Low Energy
Extraction (New York University). NOOAR Supercritical Water Oxidation, and
Critical Fluid Systems Propane Extraction processes rank very close to the top
three. Thus these seven processes merit consideration for testing at least
through the preliminary phases to confirm their performances. The Potassium
Polyethylene Glycolate process rates lower primarily because of the high esti-
mated cost of treatment.
The Low Energy Extraction process has a low rating because of the rela-
tively higher cost of development that may be necessary and the length of time
to commercialization. Uncertainty about the possible commercial sponsorship
led to the lower rating for availability of a test unit. The $827,000 Test &
Evaluation cost includes the cost of a pilot unit, however. For the other
processes, this cost was not Included because it was contributed by the
developer or had already been purchased by the government. The estimated cost
of treatment using this process is lower, however, than any other process. If
this estimated cost could be attained, the development cost for the process
adds only $2.17/n3 of sediment treated:
15
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T*ft£ 3. MMU. OSIMBIUTY OF MQIATE T AND E OF THE HOT OMIMTC PBggg
Probability of clean-
Ing tD<2ppe
d ratlfig
FT09HDM GDft OT
. »i_3
Grenenc, J/B*
d rating
T and E ei'ori
$1000
d rating
Availability of a
fyetee for a tart
jtura purdne by
govern, raoulrad
futerapunJuee by
govern, not required
d rating
Lflerty futura avall-
etnlTty or tre prooeei
OMammmm
BUIUB
d rating
OMrall detlrablllty, 0
erllett futura evedl.
latBt future avail.
KFGB.
feleon
0.9
0.63
160-191
0.54*
216
0.66
0.9
0.63
19.5
0.62
0.615
0.615
0.615
fcdar
Supercritical
Hater
O.I
0.59
86-136
0.62
483
0.56
0.9
0.63
21.5
0.59
0.60
0.60
0.60
Bio-Clem
0.8
0.63
156
0.57
166
0.68
0.9
0.63
19
0.62
0.617
0.617
0.617
W/tam-
HydrogW
Ultraetnla
Tadnology
0.8
0.59
90-120
0.63
151
0.69
0.9
0.63
21-24
0.59-0.55
0.625
0.616
0.621
CfS
Extraction
0.8
0.59
153-264
0.50
123
0.69
0.9
0.63
25
0.54
0.59
0.59
0.59
u»*»w
8.E.S.T. Extraction
0.8 0.9
0.59 0.63
133 50-57
0.59 0.68
149 ITO-eZT*
0.69 0.64
0.8
0.9
0.63 0.59
19 25
0.62 0.54
0.623 0.614
0.623 0.614
0.623 0.614
InSItu
Vltrlflcsti
0.9
0.63
443483
0.16
400
0.59
0.8
0.59
19-24
0.62-0.55
0.46
0.45
0.46
of $170,000' 1f
by epmearlng fin. A
«t of $280,000 *» «a 1n the ^k«1m to allot fcr tfe uorealnty.
16
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$827.000 + 380.000 »3 - $2.17.
•Mis would have a small impact on the final treatment cost. If added to the
estimated $76-$83/m3. From this point of view, the major obstacle to a higher
rating for this project is the 25-month development time required, and the
lack of a firmly committed commercial sponsor for the test system.
The NOOAR process has a high T and E cost, but a potential application to
a broad range of contaminants besides PCBs.
The In Situ Vitrification process has the highest estimated cost of treat-
ment, which derives in significant proportion from the cost of electricity and
consumable electrodes used in the treatment. As previously mentioned, the
advantages of in situ treatment could not be bad in the treatment of submerged
sediments. The fact that a solid mass is the product presents a problem in
disposal. The process appears best suited for in-situ fixation of radioactive
wastes.
APPLICATION OF ALTERNATIVE PROCESS SELECTION METHODOLOGY
While this project was under way, an alternative process selection method-
ology became available at HWERL. The methodology is available as a computer
•Bgram entitled "d-SSVS. A Computer Model for the Evaluation of Competing
Uncertainties," (Klee. 1987). This method was applied In addition to the
Desirability Function approach.
The D-SSYS calculates weights for each evaluation factor using values of
weight ratios assigned by the user. Weight ratios were assigned to emphasize
the Importance of the ranges of treatment cost and test-and-evaluatlon cost.
The range of ratings for probability of cleaning to <2 ppm PCBs is only 0.1
(Table 3), Indicating that all the processes might reasonably be expected to
meet the requirement. The availability of a test system was not considered as
Important as the total test and evaluation cost. The time required to make a
commercial process available showed a range of only six months, and was judged
of lesser importance than the two major costs assessed. All ratios among the
five factors that resulted from these assignments are shown below as a matrix.
For example, the ratio (test system avallablllty)/(T and E cost) is shown as
the intersection of Row 4 and Column 3 as 0.2.
17
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Clean to 2 ppm
Cost
T and E Cost
Test system availability
Early com. availability
Clean
to
2 ppm
1
5
S
1
1.25
Cost
0.2
1
1
0.2
0.25
T & E
Cost
0.2
1
1
0.2
0.25
Test System
Availability
1
5
5
1
1.25
Early
Commercial
Availability
0.8
4
4
0.8
1
Prom these ratios and the following tabular algorithm, the factor weights
(W) were generated.
Factors
Clean to 2 ppm
T and E Cost
Future commercial proc.
Test system availability
Cost
Ratios
0.2000
4.
1.
0.
000
25
2000
0.20
1.00
0.25
0.20
5.000
Weights.
0.0755
0.3774
0.0943
0.0755
0.3774
2.65
The procedure for weight generation is as follows:
Construct an Intermediate weighting scale (the w-column) by the follow-
ing procedure. Opposite that last factor enter a "1". The remaining
numbers in this column are formed by the product of its predecessor and
Ratio value opposite it in a sort of zigzag route up the column. For
example, the first w-value, 0.20 is the product of the second w-value
(1.00) and the first Ratio-value (0.2000).
• Total the w-values. This total is 2.65. Construct a column of stan-
dardized weights by dividing each element of the w-column by this total
to obtain the W-column. The elements in the W-column will, perforce.
total one.
The program then scales the factor scores to obtain a linear utility func-
tion:
y1 « b0 + bj (factor score)
0 < y1 < 1.
(5)
In applying the scaling procedure to the two factors "Probability of
Cleaning to £ 2 ppm" and "Availability of a Test System," It is noted that
these are positive factors (the higher the factor score, the better the proc-
"s_L and the 'y1 values are obtained by:
18
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score}j - •inimua score}4
maximum score£j - minimum scorejj
(6)
The other three factors are noted to be negative (the higher the factor score,
the worse the process) and the y1 values are obtained by:
maximum scorej.| - acorejj
maximum scorejj - minimum score
ij
(7)
The yjj values for the five factors by which each of the eight processes
were assessed are given In Table 4.
TABLE 4. SCALED RATINGS OF EIGHT TREATMENT PROCESSES
Clean
2
KPEG (Gal son)
MODAR
Bio-Clean
UV/OZ or H2/Ultrasonlcs
§ Propane Extraction
.S.T.
Energy Extraction
In Situ Vitrification
to
pp»
1
0
0
0
0
0
1
1
Probable
Tr. Cost
0.60
0.87
0.67
0.89
0.45
0.77
1
0
T & E
Cost
0.75
0.043
0.89
0.93
1
0.93
0
0.26
Test System
Availability
1
1
1
1
1
1
0
0
Early
Commercial
Availability
0.92
0.58
1
0.42
0
1
0
0.58
Depending on the users degree of risk that he is willing to accept. d-SSYS
fits a utility function to the y1 values via the following function:
utility « y'f . (8)
The exponent f is evaluated by presenting the user with a structured lottery.
d-SSYS requires s comparison between two simple lotteries for each factor
rated.
Lottery 1
SOX chance of most undesirable rating.
SOX chance of most desirable rating.
19
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Lottery 2 « | X value of the ratine for certain.
I
Using probable treatment cost as an example, RTI selected for Lottery 1:
SOX chance of a treatment cost of $313/m3
SOX change of a treatment cost of $80/m3
and an X value equal to the mathematical expectation of Lottery 1 for
Lottery 2:
(0.5 X $313) + (O.S X 80) « $196.50/m3.
The value of $196.50/m3 on the y' scale is
$313 - $196.6
y« - « 0.5
$313 - $80
The utility of Lottery 2 is easily determined, since it is equal to the
utility of Lottery 1:
(0.5)(utility of $313/m3) + (0.5)(utility of $80/m3) -
(O.S x 0.0) + (0.5 x 1) - 0.5.
^^m Equation 8:
f - (In utility)/ln y' (9)
f - (In 0.5)/ln 0.5 • 1
Note that if Lottery 2 had been set at a lower cost for certain, f would
have been greater than 1 and the function would have been a risk-taking one,
in that one would be willing to pay more for Lottery 1 in the hope of gaining
a treatment cost of $80/m3.
The remaining utilities for each factor are then calculated using Equation
8 (Klee, 1987, p. 23).
Using the ratings scaled by Equation 8, the program computes an overall
deterministic score for each treatment process as the sum of the scaled factor
ratings times the scaled factor weights. Using the factor ratings of Table 44
(which equal the utility when f - 1) and the weights cited above, the follow-
ing deterministic scores were obtained for the treatment processes (Table 5).
20
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TABLE 5. DETERMINISTIC SCORES FOR TREATMENT PROCESSES
Proce88 Score
Basic Extraction Sludge Treatment 0 8127
UV/Ozone or Hydrogen/Ultrasonics 0 8010
Bio-Clean Naturally-Adapted Microbe 0 7583
Potassium Polyethylene Glycolate. Galaon 0 7434
Critical Fluid Systems (CFS) Propane Extraction 0 6214
MOOAR Supercritical Water Oxidation 0*4738
Low Energy Extraction. New York University 0
In Situ Vitrification. Batteile '
The highest scores were attained by the Basic Extraction Sludge Treatment,
UV/Ozone or Hydrogen/Ultrasonics Technology, and Bio-Clean Naturally-Adapted
Microbe processes, the same processes that ranked highest using the Desir-
ability Function ranking methodology. These are recommended for Immediate
test and evaluation.
In the application of this ranking, probable treatment cost and test and
evaluation cost were assigned weights 4 to 6 times those of the other three
gctors. This Increased emphasis on the costs involved did not change the top
Pree processes. With different weights assigned, it would be possible to
obtain a different ranking of the processes.
CONCLUSIONS
Eight emerging treatment processes for decontamination of PCB-contaminated
sediments have been evaluated as candidates for thorough test and evaluation
(T and E) using a test system judged of sufficient size by the developer to
provide performance, cost, and sealeup data for a large commercial plant. The
processes assessed include: Basic Extraction Sludge Treatment (B.E.S.T); Bio-
Clean Naturally-Adapted Microbe; Critical Fluid Systems Propane Extraction;
Potassium Polyethylene Glycolate. Galson; Low Energy Extraction. New York
University; MODAR Supercritical Water Oxidation; UV/Oxone or Hydrogen/Ultra-
sonics Technology; and Batteile In Situ Vitrification.
The processes were evaluated using as criteria:
• The probability of cleaning sediments to <2 ppm PCBs;
• The probable cost of treatment:
21
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• The relative level of Test and Evaluation effort to be supported by
EPA;
• The availability of a processing system to test; and
• The likely future commercial availability of the process.
While all the processes except perhaps In Situ Vitrification merit further
development for treatment of sediments, comparative simultaneous evaluation of
their ratings on a scale of 0 to 1 gave the following results:
Relative Desirability of
Thorough Test and Evaluation
Desirability d-SSYS
Process score score
Basic Extraction Sludge Treatment, 0.623 0.8127
Resources Conservation Company
UV/Ozone or Hydrogen/Ultrasonics Treatment. 0.621 0.8010
Ozonic Technology, Inc.
Naturally-Adapted Microbes Process, 0.617 0.7583
Bio-Clean. Inc.
Polyethylene Glycolate (KPEG), 0.615 0.7434
Research, Corp.
Extraction. New York University 0.614 0.4529
Supercritical Water Oxidation, MODAR, Inc. 0.600 0.4738
Propane Extraction Process, 0.590 0.6214
Critical Fluid Systems
In Situ Vitrification, Battelle 0.460 0.2299
The Basic Extraction Sludge Treatment Process (Resources Conservation
Co.), UV/Ozone or Hydrogen/Ultrasonics Technology, and Bio-Clean Naturally-
Adapted Microbe processes have the highest ratings, and are recommended for
immediate thorough test and evaluation. This evaluation was confirmed using
the d-SSYS Computer Model for the Evaluation of Competing Alternatives (Klee.
1987).
The Potassium Polyethylene Glycolate (Galson). Low Energy Extraction (New
York University), MODAR Supercritical Water Oxidation, and Critical Fluid
Systems Propane Extraction processes ranked very close to the top three.
These processes have potential for treatment of a broad range of hazardous
contaminants and are recommended for at least those preliminary phases of
^ough test and evaluation which confirm performance and establish process
Peters for pilot-scale tests.
References cited are identified fully in the full report.
22
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Ben H. Carpenter is with the Research Triangle Institute, Research
Triangle Park. NC 27709. Donald L. Wilson and T. David Ferguson are the
EPA Project Officers (see below). The complete report, entitled "PCB
Sediment Decontamination Processes - Selection for Test and Evaluation."
(Order No. PB , Cost , subject to change),
will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: (703) 487-4650
The EPA Project Officer can be contacted at:
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati. OH 45268
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