United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/AR-9a'002
August 1992
v>EPA
The Carver-'
Process®
Dehydro-Tech Corporation
Applications Analysis Report
P
i
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
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The Carver-Greenfield Process
Dehydro-Tech Corporation
Applications Analysis Report
EPA/540/AR-92/002
August 1992
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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Notice
The information in this document has been prepared for the U.S. Environmental
Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) program
under Contract No. 68-CO-0047. This document has been subjected to EPA peer and
administrative reviews and approved for publication as an EPA document. Mention of trade
names or commercial products does not constitute an endorsement or recommendation for
use.
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Foreword
The Superfund Innovative Technology Evaluation (SITE) Program was authorized
in the 1986 Superfund Amendments and Reauthorization Act. The program is administered
by the U.S. Environmental Protection Agency (EPA) Office of Research and Development.
The purpose of the program is to accelerate the development and use of innovative cleanup
technologies applicable to Superfund and other hazardous waste sites. This is accomplished
through technology demonstrations designed to provide performance and cost data on
selected technologies.
A field demonstration was conducted under the SITE Program to evaluate the
Carver-Greenfield Process®, developed by Dehydro-Tech Corporation. The demonstration
was conducted at the Risk Reduction Engineering Laboratory's Releases Control Branch
facility in Edison, New Jersey. The demonstration effort assessed the technology's ability
to treat hazardous wastes based on performance and cost. Documentation consists of two
reports: (1) a Technology Evaluation Report, which describes the field activities and
laboratory results and (2) this Applications Analysis Report, which interprets the data and
discusses the potential applicability of the technology.
A limited number of copies of this report will be available at no charge from EPA's
Center for Environmental Research Information, 26 West Martin Luther King Drive,
Cincinnati, Ohio, 45268. Requests should include the EPA document number found on the
report's cover. When the limited supply is exhausted, additional copies can be purchased
from the National Technical Information Service, Ravensworth Building, Springfield,
Virginia, 22161,703/487-4600. Reference copies will be available at EPA libraries in the
Hazardous Waste Collection. To inquire about the availability of other reports, call the SITE
Clearinghouse hotline at 800/424-9346 or 202/382-3000 in Washington, D.C.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
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Abstract
This reportevaluates the Dehydro-TechCorporation'sCarver-Greenfield(C-G) Process™
and focuses on the technology's ability to separate waste mixtures into their constituent solid,
organic, and water fractions while producing a solid residual that meets applicable disposal
requirements. This report presents performance and economic data from the U.S. Envi-
ronmental Protection Agency Superfund Innovative Technology Evaluation (SITE) dem-
onstration and three case studies.
The C-G Process separates hazardous solvent-soluble organic contaminants (in-
digenous oil) from sludges, soils, and industrial wastes. The process involves adding waste
to a solvent which extracts hazardous organics from contaminated solid particles and
concentrates them in the solvent phase. In most applications, a food-grade hydrocarbon with
a boiling point of about 400 °F is used as the solvent. Typically, 5 to 10 Ib of solvent per Ib
of solids are used. First, the waste is added to the solvent in a mixing tank. The mixture is
then transferred to a high-efficiency evaporator where the water is removed by vaporization.
Next, the dry mixture is fed to a device that separates the solvent from the solid particles.
Subsequentextractions of thedry solids may be made with clean recycled solvent. After final
ser>aradonbycentrifugmg)anyresidualsolventisremovedbyhydroextraction)adesolventizing
process that uses hot nitrogen gas or steam to separate the solvent from the solids. The final
solids product typically contains low percentages of water (<5 %) and solvent (<1%). In the
full-scale system, spent solvent containing indigenous oil is distilled to separate the
indigenous oil from the solvent. The solvent is subsequently reused in the process. Products
from the process include (1) clean dry solids, (2) a water product virtually free of solids and
indigenous oil, and solvent and (3) extracted solvent-soluble compounds (indigenous oil).
The C-G Process demonstration was conducted as a part of the SITE Program at the
Risk Reduction Engineering Laboratory's Releases Control Branch facility in Edison, New
Jersey, using drilling mud waste from the PAB Oil Superfund site in Abbeville, LA. During
the demonstration, the C-G Process pilot plant experienced no major operational problems.
During startup and shakedown, the system exhibited minor, repairable problems.
The system generated a treated solids product that passed Toxicity Characteristic
Leaching Procedure (TCLP) criteria for volatiles, semivolatiles, and metals. The system
successfully separated the feed stream into its constituent water, indigenous oil, and solids
fractions, and produced a dry final solids product containing less than 1% solvent.
Potential wastes that might be treated by this technology include industrial residues,
Resource Conservation and Recovery Act wastes, Superfund wastes, and other wastes
contaminated with organic compounds. The technology is especially applicable to wastes
with high water content. A brief overview of the results from the C-G Process case studies,
which discuss wastes treated by the technology, is presented in Appendix D.
Economic data indicate that the cost of treating wastes similar to those treated in the
SITE demonstration, including disposal of residuals, is about $523 per wet ton of feed, of
which $221 is C-G Process technology-specific and $302 is site-specific. Of the $302 per
ton site-specific cost, about $240 per ton is for the incineration of indigenous oil separated
from the feed.
IV
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Contents
Foreword iii
Abstract iv
Figures ; vii
Tables vii
, Abbreviations and Symbols viii
Acknowledgments x
1.0 Executive Summary 1
1.1 Background 1
1.2 Overview of the SITE Demonstration 1
1.3 Waste Applicability .*. 2
1.4 Economics 2
1.5 Results from the SITE Demonstration 2
2.0 Introduction .-. 3
2.1 Purpose, History, and Goals of the SITE Program 3
2.2 Documentation of the SITE Demonstration Results .'. 4
2.2.1 Technology Evaluation Report 4
2.2.2 Applications Analysis Report 4
2.3 Technology Description 4
2.4 Key Contacts 5
3.0 Technology Applications Analysis 7
3.1 Introduction...., 7
3.2 SITE Demonstration Objectives 7
3.3 Summary .of the SITE Demonstration 7
3.4 Conclusions 8
3.5 Potential Regulatory Requirements ''.'. 8
3.5.1 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).... 8
3.5.2 Resource Conservation and Recovery Act (RCRA) 12
3.5.3 Clean Water Act (CWA) 13
3.5.4 Safe Drinking Water Act (SDWA) 13
3.5.5 Clean Air Act (CAA) ., 13
3.5.6 Toxic Substances Control Act (TSCA) , 13
3.5.7 Occupational Safety and Health Act (OSHA) 13
3.6 Impact of Waste Characteristics on Technology Performance 13
3.7 Materials Handling Required by the Technology 14
3.8 Community Impact 14
3.9 Personnel Issues 14
4.0 Economic Analysis - 15
4.1 Site-Specific Factors Affecting Cost 15
4.2 Basis of Economic Analysis 15
4.2.1 Site Preparation Costs 16
4.2.2 Permitting and Regulatory Costs 16
4.2.3 Capital Equipment Costs 16
4.2.4 Startup and Fixed Costs 16
4.2.5 Labor Costs 17
4.2.6 Supplies Costs 17
4.2.7 Consumables Costs 17
4.2.8 Effluent Treatment and Disposal Costs 17
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4.2.9 Residuals Shipping, Handling, and Transportation Costs 17
4.2.10 Analytical Costs 17
4.2.11 Equipment Repair and Replacement Costs 18
4.2.12 Site Demobilization Costs 18
4.3 Summary of Economic Analysis 18
References , 18
Appendix A Carver-Greenfield Process Description 19
A.1 Background 19
A.2 The Carver-Greenfield Process System 19
A.2.1 Slurrying 19
A.2.2 Evaporation/Heat Exchange 19
A.2.3 Centrifuging 19
A.2.4 Desolventization 19
A.2.5 Distillation 20
A.2.6 Oil/Water Separator 20'
A.2.7 Vent Gases 20
A.2.8 Pilot Scale Applications 20
References .'. 21
•
Appendix B Vendor's Claims for the Technology 23
B.I Introduction 23
B.2 Process Description ; 23
B.3 Process Economics .'. 25
Appendix C Carver-Greenfield SITE Demonstration Test Results 29
C.I The PAB Oil Site 29
C.2 Description of Operations 29
C.3 Analytical Results and Discussion 30
C.3.1 Feed Characterization 30
C.3.2 Summary of the Major Analytical Parameters 31
C.3.3 Characterization of Oil Removal Efficiency , 31
C.3.4 TCLP Results 34
C.3.5 Mass Balance 35
References 35
Appendix D Carver-Greenfield Process Case Studies 37
vi
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Figures
2-1 Simplified Process Flow Diagram-The Carver-Greenfield Process 4
3-1 Indigenous Oil Removal for Test Run 1 11
3-2 Indigenous Oil Removal for Test Run 2 11
A-l General Process Schematic for Commercial C-G Systems 20
B-l C-G Process Licensed Capacity 23
B-2 C-G Process Block Flow Diagram 24
B-3 Particle Size Distribution of C-G Processed Solids from PAB Oil Site 25
Tables
3-1 Carver-Greenfield Process Averages, Test Run 1 , 9
3-2 Carver-Greenfield Process Averages, Test Run 2 10
3-3 Oil Removal Efficiency, Expressed as Percentage Removal from Waste Feed 12
4-1 Estimated Costs Associated with the C-G Process Technology . 16
B-l Particle Size Analyses-Product Solids-PAB Oil Site 24
B-2 Estimates for a Carver-Greenfield Process Plant 26
B-3 C-G Process-Economic Sensitivity Cases-PAB Oil Site 27
C-l Composition of Waste Feeds "... 30
C-2 Carver-Greenfield Process-Test Run 1 31
C-3 Carver-Greenfield Process-Test Run 2 32
C-4 Oil Parameters for Feedstock and Final Product 32
C-5 Oil Removal Efficiency Percent Removal 33
C-6 Toxicity Characteristic Regulatory Limits and TCLP Results from Test Run 1 Treated Solids 33
C-7 Toxicity Characteristic Regulatory Limits and TCLP Results from Test Run 2 Treated Solids 34
D-l Sample Composition 37
D-2 Feed Compositions 38
D-3 Deoiled Product Solids Properties 38
D-4 Wool Scouring Waste Composition 39
D-5 Commercial Plant Feed Composition 39
VII
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Abbreviations and Symbols
ARAR Applicable or relevant and appropriate requirements
BOD Biochemical Oxygen Demand
Btu British thermal unit
Btu/lb Btu per pound
CAA Clean Air Act
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
C-G Carver-Greenfield
COD Chemical Oxygen Demand
CWA Clean Water Act
DOT U.S. Department of Transportation
DTC Dehydro-Tech Corporation
EPA U.S. Environmental Protection Agency
FR Federal Register
g Gram
H/> Water
hr Hour •
kg Kilogram
L Liter
LDR Land Disposal Restrictions
Ib Pound
Ib/hr Lb per hour
mg Milligram
mg/L Mg per liter
N2 Nitrogen
NPDES National Pollutant Discharge Elimination System
ORD EPA Office of Research and Development
OSHA U.S. Occupational Safety and Health Administration
Pb Lead
PCB Polychlorinated biphenyl
POTW Publicly Owned Treatment Works
ppm Parts per million
psi Pounds per square inch
viii
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QA Quality assurance
QC Quality control
RCRA Resource Conservation and Recovery Act
RFP Request for proposal
SARA Superfund Amendments and Reauthorization Act
scf Standard cubic feet
SCFH Standard cubic feet per hour
SDWA Safe Drinking Water Act
sec Second
SITE Superfund Innovative Technology Evaluation
SOW Solids/Oil/Water Analysis
SSM Synthetic Soil Matrix
SVOC Semivolatile organic compound
TCLP Toxicity Characteristic Leaching Procedure
TPH Total Petroleum Hydrocarbons
TSCA Toxic Substances Control Act
Mg Microgram
VOC Volatile organic compound
wt Weight
IX
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Acknowledgments
This report was prepared under the direction and coordination of Laurel Staley, U.S.
Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation
(SITE) Project Manager at the Risk Reduction Engineering Laboratory, Cincinnati, Ohio.
This report was prepared for EPA's SITE program by Thomas Raptis, Deidre
Knodell, and Ken Partymiller of PRC Environmental Management, Inc., and Karl Scheible,
Gary Grey.andAshokGupta of HydroQual, Lie. PRCandHydroQual performed the process
sampling; and General Testing Corporation performed the chemical analyses for this SITE
demonstration.
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Section 1
Executive Summary
1.1 Background
In 1986, the U.S. Environmental Protection Agency (EPA)
established the Superfund Innovative Technology Evaluation
(SITE) Program to promote the development and use of
innovative technologies to remediate Superfund sites. Tech-
nologies in the SITE Program are analyzed in two documents,
the Technology Evaluation Report and this Applications
Analysis Report The Applications Analysis Report evaluates
the applicability and estimates the costs of the Dehydro-Tech
Corporation's (DTC) Carver-Greenfield (C-G) Process® based
on available data. Data not generated from the SITE demon-
stration were obtained from DTC, the technology developer.
DTC's data are based on 25 years of commercial-scale op-
erations of the C-G Process™ treating nonhazardous munici-
pal and industrial wastes.
The C-G Process was evaluated under EPA's SITE Pro-
gram, based on a Demonstration Plan agreed to by EPA and
the developer. The demonstration was conducted at an EPA
research facility in Edison, NJ, in August 1991, using drilling
mud waste from the PAB Oil and Chemical Services (PAB
Oil) Superfund site in Abbeville, LA.
The primary objectives of the C-G SITE demonstration
included the following:
• To assess how well the C-G Process effectively
separates petroleum-based hydrocarbon contaminated
drilling mud wastes into their constituent solid, oil
and water fractions
To evaluate the C-G Process's reliability
• To develop overall economic data on the C-G Pro
cess
Secondary objectives included the following:
To assess the ability of the C-G Process to remove
volatile and semivolatile organic contaminants and
metals from solids
To document the operating conditions of the C-G
Process for application to hazardous waste sites
• To characterize residuals (water, oil, and solids) rela-
tive to applicable standards for final disposal or further
treatment
This report provides information based on the results
from the SITE demonstration and related case studies; this
information is necessary if the C-G Process technology is to
be considered for use on Superfund and Resource Conserva-
tion and Recovery Act (RCRA) hazardous waste sites. Section
2 of this report presents an overview of the SITE Program,
explains how SITE Program results are documented, and lists
key contacts. Section 3 discusses the SITE demonstration
objectives and describes the C-G Process technology. It also
briefly describes the demonstration and its findings regarding
the technology's application, including potentially applicable
environmental regulations, the effects of waste characteristics
and operating parameters on technology performance, material
handling requirements, community impact, and personnel is-
sues. Section 4 summarizes the costs of implementing the
technology. Appendices A through D include the following:
1) a detailed description of the C-G Process, 2) DTC's claims
regarding the technology, 3) a summary of the SITE demon-
stration results, and 4) information from case studies prepared
by DTC.
1.2 Overview of the SITE Demonstration
The C-G Process was demonstrated at an EPA research
facility in Edison, NJ in August 1991. About 640 Ib of
drilling mud waste was treated during all phases of testing.
Drilling mud, a material that circulates around drilling augers
during oil production activities, consists of oils, solids, and
water and is difficult to separate using conventional techniques
such as sedimentation. As a result, many Superfund sites in
oil-producing states are contaminated by drilling muds similar
to those at the PAB Oil site.
The drilling mud waste at the PAB Oil site was exca-
vated, passed through a 1/4-in. screen, collected in five 55-gal
drums, and shipped to EPA's Edison, NJ facility. The dem-
onstration of the C-G Process included a series of shakedown
runs to establish optimal operating conditions, a blank run
with no waste treatment, and two test runs.
Extensive process operating data and numerous liquid
and solid samples were collected for analysis. Operating data
were monitored and recorded, including raw waste feed rate,
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nitrogen consumption rates, electrical consumption, and tem-
peratures and pressures throughout the system.
Laboratory analyses included analyses of the raw
feed and solids product for Solids/Indigenous Oil/Water (SOW)
content, a measure of the C-G Process's separation efficiency.
This test uses an extraction procedure to quantify the percentage
of solids, indigenous oil, and water in untreated and treated
samples. Solids effluent samples were also analyzed for
Toxicity Characteristic Leaching Procedure (TCLP) criteria.
Water effluent samples were analyzed for organics and metals
content. Analytical data are summarized in Section 3.3 and
given in greater detail in Appendix C.
1.3 Waste Applicability
The C-G Process can treat wastes containing water
and organic contaminants. Commercial C-G Process plants
have treated materials with high water contents, such as meat
rendering waste, municipal sewage sludge, paper mill sludge,
brewery treatment plant sludge, pharmaceutical plant waste,
and leather dyeing waste. Because the process uses a dewa-
tering technology, it can treat waste streams containing up to
99% water. The C-G Process can treat wastes with solvent-
soluble contents ranging from parts per million (ppm) levels
up to 75%. Since the system cannot process large particles, a
grinder can be used to reduce the size of influent solids to a
maximum particle size of about 1/4 in.
1.4 Economics
An economic analysis was performed on 12 separate cost
categories. Because this analysis is based on a C-G Process
unit not yet constructed, the costs presented are order-of-
magnitude estimates (-30% to +50%). Cost estimates are
based on using a C-G Process unit with a feed capacity of 1.4
tons/hr. Based on the assumptions made in the economic
analysis, the estimated cost per wet ton for treating drilling
mud waste at a site similar to the PAB Oil site is $527, of
which $225 per ton is technology-specific and $302 per ton is
site-specific. However, these figures depend on the quantity
of waste to be treated and the level of treatment required.
Also, factors such as residual transportation and disposal costs
can vary greatly depending on specific site and waste charac-
teristics.
1.5 Results from the SITE Demonstration
The following overall conclusions about the Carver-
Greenfield Process technology are drawn from the results of
the SITE demonstration.
1) The Carver-Greenfield Process separated a petroleum
oil-contaminated waste drilling mud into its solids, oil,
and water phases. The C-G Process removed about
90% of the indigenous oil (as measured by SOW). No
detectable levels of indigenous total petroleum hydro-
carbons (TPH) were found on the solids product from
both test runs.
2) The final solids product from the demonstration is a
dry powder similar in character to dry bentonite. Isopar-
L solvent, a food grade oil, comprises the bulk of the
residual oil content on the final solids product
3) Values for all metals and organics are well below the
RCRA Toxicity Characteristic Leaching Procedure
(TCLP) limits for characteristic hazardous wastes. Ad-
ditionally, the indigenous TPH concentrations were
reduced to trace levels on the final solids product
Residues from the C-G Process may still require disposal
as hazardous materials, due to the regulatory con-
straints governing the disposal of Superfund wastes.
4) The C-G Process, as demonstrated on the PAB Oil site
wastes, does not remove metals bound to the solids
phase. The process may increase the apparent metals
concentration in the solids fraction by volume reduction.
5) The resulting water product requires further treatment
due to the presence of light organics and solvent In
some cases, the wastewater may be disposed of at a
local publicly owned treatment works (POTW).
6) A full-scale C-G Process system can process drilling
mud waste from the PAB Oil site at an estimated cost
of $523 per wet ton of feed. Of this total, $221 is C-G
Process technology-specific, and $302 is site-specific.
Of the $302 per ton site-specific cost, about $240 is for
the incineration of indigenous oil separated from the
feed. Treatment costs are highly site-specific, and
accurate cost estimation requires data from a site re-
medial investigation or waste profile, as well as specific
treatment goals. Variability in the waste characteristics
or pretreatment requirements could significantly affect
treatment costs.
Dehydro-Tech has prepared an independent cost analysis
of the Carver-Greenfield Process. It appears in Appendix B.
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Section 2
Introduction
This section provides background information about
EPA's SITE Program and discusses the purpose of the Appli-
cations Analysis Report. It also briefly describes the C-G
Process. Appendix A describes the C-G Process in detail. For
additional information about the SITE Program and the C-G
Process techriology contact the individuals listed at the end of
this section.
2.1 Purpose, History, and Goals of the SITE
Program
EPA's SITE Program is dedicated to advancing the de-
velopment, evaluation, and implementation of innovative
treatment technologies applicable to hazardous wastes and
hazardous waste sites. The SITE Program was established in
response to the 1986 Superfund Amendments and
Reauthorization Act (SARA), which recognized a need for an
alternative or innovative treatment technology research and
development program. The SITE Program is administered by
EPA's Office of Research and Development (ORD).
The SITE Program's major goals are the following:
To identify and remove impediments to the develop-
ment and use of alternative technologies
• To demonstrate promising innovative technologies and
establish reliable performance and cost information for
site characterization and cleanup
• To develop procedures and policies that encourage
selection of alternative treatment remedies at Superfund
sites
• To provide a development program that nurtures
emerging technologies
The SITE Program consists of four component programs:
(1) Demonstration Program, (2) Emerging Technology Pro-
gram, (3) Measurement and Monitoring Technologies Devel-
opment Program, and (4) Technology Information Services.
This document was produced as part of the Demonstration
Program. The SITE Demonstration Program's objective is to
develop reliable performance and cost data on innovative
technologies so that potential users can assess whether a
technology might apply to specific sites.
Demonstration data are used to assess the performance of
the technology, the potential need for pretreatment and post-
treatment processing of the waste, applicable types of waste
and media, potential operating problems, and approximate
capital and operating costs. Demonstration data can also
provide insight into long-term operating and maintenance
costs and long-term risks.
ORD selects technologies for the SITE Demonstration
Program through annual requests for proposals (RFP). ORD
staff reviews proposals to determine the technologies with the
most promise for use. To be eligible, technologies must be at
the pilot- or full-scale stage, must be innovative, and must
offer some advantage over existing technologies. Mobile
technologies are of particular interest. Cooperative agreements
between EPA and the developer set forth responsibilities for
conducting the demonstration and evaluating the technology.
The developer is responsible for demonstrating the technology
at the selected location and paying costs to transport, operate,
and remove equipment. EPA is responsible for project plan-
ning, site preparation, sampling and analysis, quality assurance
(QA) and quality control (QC), preparing reports, disseminating
information, and transporting and disposing of treated waste
materials.
Each SITE demonstration evaluates a technology's per-
formance in treating a particular waste. To obtain data with
broad applications, attempts are made to select waste frequently
found at other contaminated sites. However, because the
waste at other sites usually differs from the tested waste, a
successful demonstration does not ensure that the technology
will work equally well at other sites. Demonstration data may
have to be extrapolated using other information about the
technology to estimate the total operating range in which the
technology will perform satisfactorily.
The amount of data available to evaluate a technology
varies widely. Data may be limited to laboratory tests on
synthetic wastes or may include performance data on actual
wastes treated by a pilot-scale treatment system. In addition,
limited conclusions can be drawn from a single field demon-
stration. A successful field demonstration does not ensure
that a technology will be widely applicable or fully developed
on a commercial scale.
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2.2 Documentation of the SITE Demonstration
Results
EPA publishes the results of each SITE demonstration in
two documents: (1) a Technology Evaluation Report and (2)
an Applications Analysis Report.
2.2.7 Technology Evaluation Report
The Technology Evaluation Report provides a compre-
hensive description of the demonstration and its results. It is
intended for engineers and others making a detailed evaluation
of the technology for a specific site and waste. Readers
should gain a detailed understanding of the technology's
performance and of the technology's advantages, risks, and
costs for a given application. This information helps to make
preliminary cost estimates for the technology. This informa-
tion also aids potential users of the technology.
2.2.2 Applications A nalysis Report
The Applications Analysis Report assists in evaluating
whether a specific technology should be considered further
for a particular cleanup situation. It is intended for those
responsible for implementing specific remedial actions. The
report discusses advantages, disadvantages, and limitations of
the technology. Costs for different applications are estimated
based on data for pilot- and full-scale operations. The report
also discusses factors affecting performance and cost, such as
site and waste characteristics.
EPA encourages use of demonstrated technologies by
providing information on a technology's applicability to cer-
tain sites and wastes and on the costs of these applications.
The Applications Analysis Report draws reasonable conclu-
sions about a technology's broad-range applicability, and is
therefore useful to those considering a technology for hazardous
site cleanups. The report represents a critical step in the
development and commercialization of a treatment technology ^
2.3 Technology Description
The C-G Process separates hazardous solvent-soluble
organic contaminants (indigenous oil) from sludges, soils, and
industrial wastes. The process involves adding waste to a
solvent which extracts hazardous organics from contaminated
solid particles and concentrates them in the solvent phase. In
most applications, a food-grade hydrocarbon with a boiling
point of about 400 °F is used as the solvent Typically, 5 to 10
Ib of solvent per Ib of solids are used. First, the waste is added
to the solvent in a mixing tank (see Figure 2-1). The mixture
is then transferred to a high-efficiency evaporator where the
water is removed by vaporization. Next, the dry mixture is
fed to a device that separates the solvent from the solid
particles. Subsequent extractions of the dry solids may be
made with clean recycled solvent. After final separation by
centrifuging, any residual solvent is removed by
hydroextraction, a desolventizing process that uses hot nitro-
gen gas or steam to separate the solvent from the solids. The
final solids product typically contains low percentages of
water (<5%) and solvent (<1%). In the full-scale system,
spent solvent containing indigenous oil is distilled to separate
the indigenous oil from the solvent. The solvent is subsequently
reused in the process. Products from the process include (1)
clean dry solids; (2) a water product virtually free of solids,
Vent
Condenser
Feed
Sludge/Soil/
aste
Carrier Oil Vapor and Steam
Carrier Oil
Makeup
Figure 2-1. Simplified Process Flow Diagram — The Carver-Greenfield Process.
4
-> Light
OHSolluble
Components
Extracted
OHSolluble
Components
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indigenous oil, and solvent; and (3) extracted solvent-soluble
compounds (indigenous oil). Note that Figure 2-1 refers to
the extraction solvent as carrier oil.
2.4 Key Contacts
Additional information on the Carver-Greenfield Process
technology and the SITE Program can be obtained from the
following sources:
1. Vendor concerning the process:
Thomas C. Holcombe
President
Dehydro-Tech Corporation
6 Great Meadow Lane
E. Hanover, NJ 07936
201/887-2182
FAX 201/887-2548
2. EPA Project Manager concerning the SITE Demon-
stration:
Laurel Staley
U.S. EPA - ORD
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513/569-7863
FAX 513/569-7620
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Section 3
Technology Applications Analysis
3.1 Introduction
This section assesses the ability of the Carver-Greenfield
(C-G) Process to treat drilling mud wastes similar to waste
excavated from the PAB Oil site. This assessment is based on
the results of the SITE demonstration and on data supplied by
the technology developer, DTC. Because the results of the
demonstration are of known quality, conclusions are drawn
mainly from the demonstration results, which are summarized
in Appendix C of this report and presented in detail in the
Technology Evaluation Report (U.S. EPA, 1992). Case studies
supplied by DTC are presented in Appendix D.
The C-G Process is a patented drying and extraction
process designed to treat wastes containing solids, water, and
organics. During processing, the waste feed is fluidized with
a hydrocarbon-based solvent to extract soluble organic mate-
rials from the solids into the solvent phase. Water is then
removed from the slurry by evaporation, and the slurry is
centrifuged to separate the solids from the solvent. The solids
are processed in a desolventizer. This unit operation removes
residual solvent by evaporation and stripping by countercurrent
contacting of solids with a stripping gas, such as nitrogen. In
full-scale commercial operations, the used solvent, which
contains dissolved organics indigenous to the waste, undergoes
fractional distillation to recover the solvent and separate the
lighter and heavier indigenous organic components extracted
from the waste. The recovered solvent is recycled to the
fluidization operation, and the extracted light and heavy in-
digenous organic fractions are disposed of.
The dry solids product produced during the demonstration
did not leach metals, volatile organic compounds (VOC), or
semivolatile organic compounds (SVOC) above the RCRA
regulatory limits. Therefore, if similar TCLP results are
obtained in a full-scale remediation, the effluent solids can be
recycled as clean fill material or disposed of in a sanitary
landfill if the waste feed is not a RCRA-listed hazardous
waste. If the waste feed is a listed waste, it must be delisted
prior to disposal.
3.2 SITE Demonstration Objectives
The primary objectives of. the C-G Process SITE dem-
onstration included the following:
• To assess how well the C-G Process effectively sepa-
rates petroleum-based hydrocarbon contaminated drill-
ing mud wastes into their constituent solid, oil, and
water fractions
• To evaluate the C-G Process's reliability
• To develop overall economic data on the C-G Process
Secondary objectives included the following:
• To assess the ability of the C-G Process to remove
volatile and semivolatile organic contaminants and
metals from solids
• To document the operating conditions of the C-G Pro-
cess for application to hazardous waste sites
• To characterize residuals (water, oil, and solids) relative
to applicable standards for final disposal or further
treatment
3.3 Summary of the SITE Demonstration
In August 1991, the C-G Process was demonstrated using
about 640 Ib of drilling mud waste at a U.S. EPA research
facility in Edison, NJ. Although not considered a RCRA
hazardous waste, the drilling mud waste contains significant
quantities of indigenous oil and elevated levels of heavy
metals that could potentially leach into the environment. The
drilling mud waste was shipped to U.S. EPA in Edison, NJ
from the PAB Oil site in Abbeville, LA.
The C-G Process unit used in the demonstration was a
pilot-scale, trailer-mounted unit, capable of treating about 100
Ib/hr of waste from the PAB Oil site. The demonstration
consisted of several shakedown runs to establish operating
conditions, followed by a blank run and two test runs using
the drilling mud as waste feed. The shakedown runs, conducted
in July and August 1991, evaluated start-up and operating
conditions, feed rates, operating temperatures, nitrogen flow
rates, and other parameters.
After the shakedown runs were completed, DTC began
the blank run. Several problems were encountered during the
initial attempts to complete the blank run. The free water in
the silt/water feed produced a gummy material unsuitable for
processing, due to the potential for plugging problems. This
-------
problem is usually remedied in commercial operations by
adding a surfactant or dry treated solids to the waste feed.
Adding a surfactant produces a stable solids suspension
in the solvent for feedstocks containing free water. During the
initial blank run attenjpt, however, the SOW procedure de-
tected the surfactant chosen for start-up as indigenous oil at
unacceptable levels. Therefore, this approach was abandoned
due to the potential to produce an unsatisfactory solids prod-
uct.
The other alternative, used in some commercial operations,
is to "add-back" dry treated solids to the solvent before waste
is added. A modification of this technique was used in the C-
G Process demonstration, by which commercial dry bentonite,
a typical drilling mud component, was added to recirculating
solvent in the evaporator section. Drilling mud waste was
then added to this recirculating stream during evaporation.
Use of this technique during the demonstration caused free
water to be absorbed and evaporated, thus preventing plugging.
Each test run consisted of three individual batch extrac-
tions. During the test runs, about 640 Ib of drilling muds were
processed. Three runs were originally scheduled, but Run 3
was canceled due to scheduling limitations imposed by EPA
Region 2.
Tables 3-1 and 3-2 present average sample results for all
sample locations and parameters. Headings labeled A, B, and
C in the tables indicate the first, second, and third extractions,
respectively, for each test run. Refer to Appendix C for the
data used to develop Tables 3-1 and 3-2, as well as detailed
sampling location information.
Assessing the solids/oil/water separation efficiency of the
C-G Process was one of the primary objectives of the demon-
stration. Separation efficiency is based primarily on how well
the process removes oil indigenous to the waste. As discussed
in Appendix C, the indigenous oil consists of total petroleum
hydrocarbons (TPH), as well as other material detected as oil
by the SOW procedure. The SOW procedure is essentially a
toluene extraction, while TPH utilizes silica gel. These other
materials may be polar organics or surfactants, which are
soluble in toluene (SOW procedure) but are retained on silica
gel (TPH procedure). Since TPH is the most commonly
regulated parameter for oil content, oil removal is expressed
in terms of a new parameter, indigenous TPH. Indigenous
TPH removal is defined as feed TPH minus final product TPH
minus final product Isopar-L content. On a percentage basis,
indigenous TPH removal is the above quantity (times 100)
divided by the initial feed TPH. This calculation must be
made because Isopar-L solvent, a food grade oil not present in
the waste, is detected in the TPH procedure. This is discussed
in more detail in Appendix C and in the Technology Evalua-
tion Report (U.S. EPA, 1992). Table 3-3 presents estimated
indigenous oil and indigenous TPH removal efficiencies.
Indigenous oil removal is also shown graphically in Figures 3-
1 and 3-2.
Indigenous oil removals are lower than indigenous TPH
removals because toluene-soluble organics in the SOW proce-
dure are not detected in the TPH procedure. Indigenous TPH
removal was essentially 100% for both test runs.
Barium and silver were the only TCLP materials de-
tected. Appendix C presents a complete summary of the
TCLP results. Silver was present at concentrations slightly
above the detection limit in the final product of the second test
run. Barium results were significantly below the regulatory
limit of 100 mg/1. However, TCLP concentrations may
increase due to the way in which the process concentrates
solids. When solids increase from 50% in the feedstock to
98% in the final product, a proportional increase in the TCLP
extract should be expected due to volume reduction. There is
no evidence, however, that actual leachability of metals is
increased by the process.
3.4 Conclusions
The following overall conclusions about the C-G Process
are drawn from the results of the SITE demonstration.
1) The C-G Process separated a petroleum oil-contami-
nated waste drilling mud into its solids, oil, and water
phases. The C-G Process removed about 90% of the
indigenous oil (as measured by SOW). No detectable
levels of indigenous TPH were found on the solids
product from both test runs.
2) The final solids product from the demonstration is a
dry powder similar in character to dry bentonite. Isopar-
L solvent, a food grade oil, comprises the bulk of the
residual oil content on the final solids product.
3) Values for all metals and organics are well below the
RCR A TCLP limits for characteristic hazardous wastes.
Additionally, the indigenous TPH concentrations were
reduced to trace levels on the final solids product
Residues from the C-G Process may still require disposal
as hazardous materials, due to the regulatory constraints
governing the disposal of Superfund wastes.
4) The C-G Process, as demonstrated on the PAB Oil site
wastes, does not remove metals bound to the solids
phase. The process may increase the apparent metals
concentration in the solids fraction by volume reduction.
3.5 Potential Regulatory Requirements
This subsection discusses specific environmental regula-
tions pertinent to the transport, treatment, storage, and disposal
of wastes generated during the operation of the C-G Process
system. The regulations that apply to a particular remediation
activity will depend on the type of remediation site and the
type of waste being treated.
3.5.1 Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA)
CERCLA, as amended by the Superfund Amendments
and Reauthorization Act (SARA) of 1986, provides for federal
authority to respond to releases of hazardous substances,
pollutants, or contaminants to air, water, and land (Federal
8
-------
Table 3-1 Carver-Greenfield Process Averages, Test Run 1
Feed- Slum'ed
Parameters Units Stock Feedstock
VOC '(W/kg)
toluene (wet wt)
ethylbenzene
total xylene (o,m,p)
acetone
2-butanone (MEK)
546
993
3658
ND
ND
A
NA
NA
NA
NA
NA
B
NA
NA
NA
NA
NA
C
NA
NA
NA
NA
NA
A
NA
NA
NA
NA
NA
Final Products
Centrate
B
NA
NA
NA
NA
NA
Centrifuge Treated
Cake Solids
C
NA
:NA
NA
NA
NA
A
NA
NA
NA
NA
NA
B
NA
NA
NA
NA
NA
C
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Cond. Cond.
Water Solvent
<250
<250
<250
4927
1067
NA
NA
NA
NA
NA
SVOC - acid extractables fag/kg)
phenol (wetwt) <100000
NA
NA NA
NA
NA
" NA NA NA NA <660 <203
NA
SVOC - base neutral
extractables
phenanthrene
2-methyl naphthalene
isophorone
(wfca)
(wet wt)
bis(2-ethylhexyl) phthalate
di-n-octyl phthalate
Metals
aluminum
antimony
barium
beryllium
boron
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
molybdenum
nickel
potassium
sodium
strontium
vanadium
zinc
SOW '
solids
indigenous oil
water
Solvent
Isopar-L
TPH
Conventional
pH
alkalinity, total
acidity, total
BOD5
COD, dichromate
nitrogen, ammonia
nitrogen, Kjeldahl
solids, suspended
sulfate
ND = not detected
NA = not analyzed
(V-9'9)
(wet wt)
(%)
(bywt)
'i
(%)
(bywt)
frg/g)
(wet wt)
standard
units
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
15950
<26183
<50000
<50000
<50000
10663
<5.0
2990
0.831
<24.7
0.578
2135
25.4
7.43
16.4
13567
41.0
1517
373
<5.0
13.3
485
135
64.5
24.3
160
52.35
17.48
21.75
-------
Table 3-2. Carver-Greenfield Process Averages,
Parameters Units
VOC (V-g/kg)
benzene (wet wt)
toluene
ethylbenzene
total xylene (o,m,p)
acetone
2-butanone (MEK)
SVOC - add extractables
none (pg/kg)
(wet wt)
SVOC - base neutral
extractables
phenanthrene (pg/kg)
2-methyl naphthalene
naphthalene (wetwt)
b!s(2-ethythexyl) phthalate
dl-n-butyl phthalate
Metals (pg/g)
aluminum (wetwt)
barium
beryllium •
boron
cadmium
calcium
chromium
cobalt
copper
iron
had
magnesium
manganese
molybdenum
nickel
potassium
sodium
strontium
vanadium
zinc
SOW (%)
solids (bywt)
Indigenous oil
water
Solvent (%)
Isopar-L (by wt)
TPH frg/g)
(wet wt)
Ignltability °C
Conventional standard
pH units
alkalinity, total mg/l
acidity, total mg/l
BODs mg/l
COD, dlchromate mg/l
nitrogen, ammonia mg/l
nitrogen, Kjeldahl mg/l
solids, suspended mg/l
sulfate mg/l
ND * not detected
NA - not analyzed
Waste
Feed
1075.67
1046.00
1886.67
8873.33
<5000
<2500
ND
8126.67
49150.00
<28417
<50000
<50000
7351.67
575.83
0.70
<21.93
04.00
7785.00
139.50
9.41
88.50
20733.00
205.17
1251.67
276.00
25.35
20.83
747.17
599.17
270.67
22.03
101.33
52.44
7.24
34.77
Test Run 2
Final Products
Slurried
Feedstock
A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
11.26
5.89
<0.1
B C
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
,NA. _ NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
9.13 9.16
0.36 0.20
<0.1 0.10
<0.1 78.5391.8493.16
89383
>100
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
24.77
40.53
<0.50
<20
100
NA
NA
NA
NA
NA
NA
NA
NA
NA
<250
<250
<250
<250
2280
<395.67
ND
<50
<100
, <50
<196.27
<20.1
13.33
<0.50
<0.50
<20.0
-------
0.40
0.35
I
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Raw
Waste
Extraction
1
Figure 3-1. Indigenous oil removal for test run 1.
Extraction
2
Process Step
Extraction
3
Final
Product
I
1
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Raw
Waste
Extraction
1
Extraction
2
Process Step
Extraction
3
-O
Final
Product
Figure 3-2. Indigenous oil removal for test run 2.
11;
-------
Table 3-3.
Oil Removal Efficiency, Expressed as Percentage
Removal from Waste Feed
Test Indigenous Indigenous
Run Oil . TPH
1
2
92.1
88.3
100
100
Register, 1990). Section 121 (Cleanup Standards) of SARA
requires that selected remedies be protective of human health
and the environment and be cost-effective. SARA states a
preference for remedies that are reliable, provide long-term
protection, and employ treatment that permanently and sig-
nificantly reduces the volume, toxicity, or mobility of hazard-
pus substances, pollutants, or contaminants. The C-G Process
is one such remedy. Section 121 also requires that remedies
selected at Superfund sites comply with federal and state
applicable or relevant and appropriate requirements (ARAR),
and it provides only six conditions under which ARARs for a
remedial action may be waived: (1) the action is an interim
measure and the ARAR will be met at completion; (2) com-
pliance with the ARAR would pose a greater risk to health and
the environment than noncompliance; (3) it is technically
impracticable to meet the ARAR; (4) the standard of perfor-
mance of an ARAR can be met by an equivalent method; (5) a
state standard has not been consistently applied elsewhere;
and (6) ARAR compliance would not provide a balance
between the protection achieved at a particular site and demands
on the Superfund for other sites. These waiver options apply
only to Superfund actions taken onsite, and justification for
the waiver must be clearly demonstrated. _
Generally, treatment using the C-G Process will take
place onsile, while product water discharge and solids dis-
posal may take place either onsite or offsite. Used solvent that
is not recycled is expected to be disposed of at an offsite
facility. Onsite and offsite actions must meet the substantive
requirements (for example, emission standards) of all ARARs;
offsite actions must also meet permitting and any other ad-
ministrative requirements of environmental regulations.
3.5.2 Resource Conservation and Recovery Act
(RCRA)
RCRA regulations define hazardous wastes and regulate
their transport, treatment, storage, and disposal. Wastes defined
as hazardous under RCRA include characteristic and listed
wastes.
Criteria for identifying characteristic hazardous wastes
are included in 40 CFR Part 261 Subpart C. Listed wastes
from non-specific and specific industrial sources, off-specifi-
cation products, spill cleanups, and other industrial sources
are itemized in 40 CFR Part 261 Subpart D. For RCRA
regulations to apply, evidence (for example, manifests, records,
and knowledge of processes) must affirm that the waste is
hazardous. Site managers may also test the waste or use their
knowledge of its properties to determine if the waste is
hazardous.
Contaminated media to be treated by the C-G Process
will probably be hazardous or sufficiently similar to hazardous
waste so that RCRA standards will be requirements. Because
the system includes waste storage in tanks, 40 CFR Part 265
standards for tank storage (Subpart J) should be met Also,
RCRA treatment requirements must be met.
Treated solids generated during treatment must be stored
and disposed of properly. If the waste feed is a listed waste,
treatment residues will be considered listed wastes (unless
RCRA delisting requirements are met). If the treatment
residues are not listed wastes, they should be tested to deter-
mine if they are RCRA characteristic hazardous wastes. In
many cases, the solid residues will not be hazardous and can
be disposed of at a nonhazardous waste landfill. If the treated
solids are found to be hazardous, the following RCRA standards
apply.
40 CFR Part 262 details standards for generators of
hazardous waste. These requirements include obtaining an
EPA identification number, meeting waste accumulation
standards, labeling wastes, and keeping appropriate records.
Part 262 allows generators to store wastes up to 90 days
without a permit and without having interim status as a
treatment, storage, and disposal facility. If treatment residues
are stored onsite for 90 days or more, 40 CFR Part 265
requirements apply.
Any facility (onsite or offsite) designated for permanent
disposal of hazardous wastes must be in compliance with
RCRA. Disposal facilities must fulfill permitting, storage,
maintenance, and closure requirements contained in 40 CFR
Parts 264 through 270. In addition, any authorized state
RCRA requirements must be fulfilled. If treatment residues
are disposed off-site, 40 CFR Part 263 transportation standards
apply.
For both CERCLA actions and RCRA corrective actions,
the treatment residuals generated by the C-G Process will be
subject to land disposal restrictions (LDR) if they are hazardous
and land disposed (U.S. EPA, 1989a). Several LDR compli-
ance alternatives exist for disposing of the treated solids if
they are hazardous: (1) comply with the LDR that is in effect;
(2) comply with the LDRs by choosing one of the LDR
compliance alternatives (for example, treatability variance, no
migration petition); or (3) invoke an ARAR waiver (this
option would only apply to onsite CERCLA disposal).
40 CFR Part 264, Subparts F (promulgated) and S (pro-
posed) include requirements for corrective action at RCRA-
regulated facilities. In addition, these subparts generally
apply to remediation at Superfund sites. Subparts F and S
include, requirements for initiating and conducting RCRA
corrective actions, remediating ground water, and ensuring
that corrective actions comply with other environmental
regulations. Subpart S also details conditions under which
particular RCRA requirements may be waived for temporary
treatment units operating at corrective action sites.
12
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3.5.3 Clean Water Act (CWA)
The NPDES permitting program established under the
CWA issues, monitors, and enforces permits for direct dis-
charges to surface water bodies. Discharges to off-site receiving
waters or to publicly owned treatment works (POTW) must
comply with applicable federal, state, and local administrative
and substantive requirements. Effluent limits are contained in
the NPDES permit issued for direct discharges to off-site
receiving waters. No NPDES permits are issued for bn-site
discharges or off-site discharges to POTWs, but all substan-
tive requirements (such as discharge limitations) should be
identified and achieved.
*
3.5.4 Safe Drinking Water Act (SDWA)
The SDWA, as amended in 1986, includes the following
programs: (1) drinking water standards; (2) underground
injection control program; and (3) sole-source aquifer and
wellhead protection programs.
SDWA drinking water primary (health-based) and sec-
ondary (aesthetic) maximum contaminant levels will generally
be appropriate cleanup standards for water that is, or may be,
used as a source of drinking water. In some cases, alternate
concentration limits will be appropriate (for example, in cases
where multiple contaminants are present). Decision makers
should refer to CERCLA and RCRA standards for guidance in
establishing alternate concentration limits.
Water discharge through injection wells is regulated un-
der the underground injection program. This program cat-
egorizes injection wells as Classes I through V, depending on
their construction and use. Reinjection of treated water involves
Class IV (reinjection) or Class V (recharge) wells and should
meet the appropriate requirements for well construction, op-
eration, and closure.
The sole-source aquifer protection and wellhead protec-
tion programs are designed to protect specific drinking water
supply sources. If such a source is to be remediated, appropriate
program officials should be notified, and any potential prob-
lems should be identified before treatment begins.
3.5.5 Clean Air Act (CAA)
Pursuant to the CAA, EPA has set national ambient air
quality and pollutant emissions standards. CAA requirements
will generally not apply to the C-G Process, although they
may apply on a source-specific basis. However, air emissions
should be monitored to ensure that they comply with CAA
standards.
• RCRA air standards generally must be met for CERCLA
response actions and RCRA corrective actions. Forthcoming
RCRA regulations (40 CFR Part 269) will address air emissions
from hazardous waste treatment, storage, and disposal facili-
ties. When promulgated, these requirements will include air
emission standards for equipment leaks and process vents, a
category that will cover any fugitive air emissions from a C-G
Process unit In addition, states' programs to regulate toxic air
pollutants, when established, will be the most significant
regulations for environmental remediation activities. Gener-
ally, air emissions from the C-G Process will be minimal, and
complying with air emission regulations should not be a
problem.
3.5.6 Toxic Substances Control Act (TSCA)
The C-G Process has the capability to handle wastes
containing polychlorinated biphenyls (PCB). TSCA require-
ments set standards for PCB spill cleanups and PCB disposal
which should be achieved if PCB waste is treated. The EPA
document—CERCLA Compliance with Other Laws Manual,
Part II: Clean Air Act and Other Environmental Statutes and
State Requirements — discusses TSCA as it pertains to Su-
perfund actions (U.S. EPA, 1989b). The proposed RCRA
corrective action regulations (Federal Register, July 1990)
state that PCB waste should be handled in accordance with
TSCA PCB spill cleanup policy. As TSCA does not regulate
direct spills to surface water or drinking water, cleanup stan-
dards for these sites are established by EPA regional offices.
3.5.7 Occupational Safety and Health Act
(OSHA)
CERCLA response actions and RCRA corrective actions
must be performed in accordance with OSHA requirements
detailed in 29 CFR Parts 1900 through 1926, especially Part
1910.120, which provides for the health and safety of Workers
at hazardous waste sites. Onsite construction activities at
Superfund or RCRA corrective action sites must be performed
in accordance with Part 1926 of OSHA (Safety and Health
Regulations for Construction). For example, construction of
electric utility hookups for the C-G Process would need to
comply with Part 1926, Subpart K (Electrical). Also, any
more stringent state requirements would need to be met
3.6 Impact of Waste Characteristics on
Technology Performance
Waste feed characteristics affecting the efficiency of the
C-G Process include the following:
1) Solids Size: The maximum size of solids that the C-
G Process can handle is 1/4 in. If necessary, soils can be
pretreated Using a grinder to a maximum particle size of less
than 1/4 in. Larger particles in the feed may decrease efficiency
and cause plugging problems.
2) Solvent Soluble Content: The C-G Process can treat
wastes with solvent soluble contents from low ppm levels to
75% and higher.
3) ; Moisture Content: Waste streams of up to 99%
water can be successfully treated with the C-G Process. Wastes
containing high water contents can be pretreated with a de-
watering device if suitable.
4) Selection of Solvent: Waste characteristics gener-
ally govern the choice of carrier solvent. Extraction of
indigenous oil and organic materials from solids can be
13
-------
improved by using additives or specific solvents with a high
degree of solvency for target organic components.
3.7 Materials Handling Required by the
Technology
For an onsite remediation, materials handling is relatively
straightforward. Waste can be excavated and treated concur-
rently. The C-G Process feed hopper is used to store waste prior
to treatment. Carrier solvent can be transported to the site in
drums or in bulk, and is easily pumped to the C-G Process unit
as needed during processing. The Isopar-L solvent used in the
demonstration is a food-grade isoparaffinic oil with a high
boiling point (400 "F) and low toxicity, and does not require
special handling. Treated solids are transferred directly from the
dcsolventizer to 55-gal drums or to other containers, as required.
Residual water can be pumped to an on-site tanker truck for
offsite disposal or routed to a POTW. Contaminated carrier
solvent is pumped from the distillation unit to 55-gal drums or
other vessels for offsite disposal. Materials handling issues
specific to the demonstration are described below. During the
demonstration, the C-G Process unit was operated in a batch
mode using fresh solvent for each extraction, due to the small
quantities of waste available. In present full-scale commercial
operations, and at an actual site remediation, the C-G Process
unit will operate in batch or continuous mode along with solvent
distillation and recycle, thereby significantly reducing the need
to handle individual drums of carrier solvent
EPA performed all materials handling at the Edison facility
during the demonstration. The waste was pretreated to the
maximum particle size of 1/4 in. during excavation. Isopar-L
solvent was stored in 55-gal drums onsite. About 1,600 Ib of
solvent were charged to the fluidization tank using a fork lift.
The intent was to have a solvent to feedstock solids ratio of 10:1.
At a full-scale remediation, Isopar-L would be pumped to the C-
G Process unit from bulk tanks, thus minimizing solvent han-
dling requirements. Steam was supplied by an onsite boiler
adjacent to the C-G Process unit.
The final solids product and recovered water was virtually
free of toxics and did not require special handling. Product
water was collected in 55-gal drums. Solvent product contain-
ing organic constituents and solvent required special handling.
It was collected in 55-gal drums for disposal as a hazardous
waste and stored in a containment area. The required signs were
posted throughout the containment area.
3.8 Community Impact
The demonstration's impact on the community surrounding
the EPA facility was minimal. Potential hazards to the commu-
nity at a Superfund remediation include the following:
• Air emissions
Dust releases
• Transportation hazards
Air emissions from the C-G Process are extremely low due
to the closed configuration of the evaporator. Dust releases
from both pretreatment and processing can be minimized with
dust control equipment At a full-scale remediation, the most
significant local impact would be the erection of the evaporation
tower, a structure several stories tall, and hazards of removing
the contaminated carrier solvent from the site.
3.9 Personnel Issues
During the demonstration, the C-G Process unit operated
10 hr/day. Two operators were needed to run the C-G Process
pilot-scale unit; however, larger scale C-G Process units may
require additional operators. At the EPA facility, steel-toe shoes
and safety glasses were required. In addition, respirators were
provided for use in emergencies. Emergency eye-wash stations,
first aid kits, and fire extinguishers were located throughout the
facility.
The C-G Process contains many safety features in its
design. The unit can be shut down quickly if problems occur or
if the range of predetermined operating conditions is exceeded.
Nitrogen removes residual oil from solid particles, preventing
explosive atmospheres from forming. Also, the solvent has an
extremely low volatility, and thus does not readily generate
explosive or hazardous atmospheres.
14
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Section 4
Economic Analysis
An important goal of the SITE Program is to develop
reliable cost data for innovative and commercially available
hazardous waste treatment The purpose of this economic
analysis is to estimate costs for a full-scale remediation using
the Carver-Greenfield (C-G) Process at a Superfund site. The
C-G Process unit used during the SITE demonstration was a
pilot-scale plant, capable of treating about 100 Ib of waste per
hour (DTC, 1989). During the actual demonstration, the C-G
Process unit treated about 640 Ib of drilling mud wastes in two
test runs.
Due to its relatively low throughput, the pilot-scale C-G
Process unit is not cost-effective for a full-scale Superfund
site remediation. Therefore, costs are based on a mobile C-G
Process unit designed to treat 1.4 tons/hr at a site similar in
size and waste characteristics as the PAB Oil Superfund site.
The cost analysis presented in this section is based on treating
a total of 23,000 tons of waste.
Capital cost data for the C-G Process were obtained
primarily from DTC. Other sources of cost information
included EPA experience in CERCLA remediations and the
SITE demonstration. The costs associated with the C-G
Process have been placed into 12 cost categories applicable to
typical cleanup activities at Superfund and RCRA sites. These
cost categories are discussed in this section as they apply to
the C-G Process. Table 4-1 presents estimated costs per ton
for waste treated at a typical Superfund site with waste
material similar to the drilling mud treated in the demonstra-
tion. Treatment costs are based on treatment at the waste
location. Costs presented in this analysis are order-of-mag-
nitude estimates (-30% to +50%).
4.1 Site-Specific Factors Affecting Cost
A number of site-specific factors affect the cost of the C-
G Process. These factors can vary greatly depending on the
site being remediated. Factors affecting costs generally include
1) the volume of waste to be treated; 2) waste characteristics
such as water content, particle size distribution, and type and
concentration of contaminants in the waste; 3) treatment
goals; and 4) residual disposal costs.
4.2 Basis of Economic Analysis
The C-G Process can be applied to several types of waste,
including wastewater sludges, contaminated soils, and petro-
leum refinery wastes, such as dissolved air flotation (DAF)
sludge. This economic analysis is based on petroleum-based
drilling mud waste as the feed. Costs are presented in terms of
dollars per wet ton of feed. Not all the cost categories for
treating this particular material may apply to other types of
waste. Therefore, only applicable categories should be used
when estimating the costs for a given site.
In this economic analysis, the C-G Process unit is as-
sumed to operate 24 hr/day, 7 days/wk, and 52 wk/yr. A 24-
hr operation with an on-line factor of 70% is used. It is not
economical to shut down the C-G Process unit daily because
the energy and time required to heat the evaporator and other
heat exchange surfaces to operating temperatures entail high
costs if the system is shut down and restarted each day. The
70% factor accounts for time required to respond to operational
problems, as well as maintenance operations. Estimates for
on-line factors of 50% and 60% are discussed in Section 4.3.
For this analysis, certain assumptions, derived from the
demonstration, were made regarding the waste feed and the
operating conditions.
Assumptions Regarding Untreated Waste Feed
• The waste is a petroleum-based drilling mud similar to
the material used in the demonstration, with the follow-
ing composition by weight 52% solids; 17% indig-
enous oil; and 31% water.
• Waste is excavated and treated concurrently at the site.
The raw waste must be screened to a maximum particle
size of 1/4 in. Although drilling mud solids consist of
very small particles, some clumps of solids requiring
screening were observed during the demonstration.
Assumptions Regarding Operating Conditions
• Technicians will collect all samples and perform equip-
ment maintenance and minor repairs.
• The system operates at a waste feed rate of 1.2 yd3/hr (1.4
tons/hr).
• Operating the system requires five workers: one super-
visor, one feed operator, two system operators, and one
maintenance operator.
15
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Table 4-1. Estimated Costs Associated With the C-G Process
Technology
($ per ton of waste)
Site Preparation Costs
Site design and layout
Survey and site investigations
Legal searches
Access rights and roads •
Preparations for support facilities
Utility connections
Auxiliary buildings
Technology-specific requirements 55.00
(excavation)
Total Site Preparation Costs 55.00
Permitting and Regulatory Costs
Permits
System monitoring requirements
Development of monitoring and protocols
Total Permitting and Regulatory Costs
Capital Equipment Costs
Major equipment 21.85
Support equipment
Equipment rental
Total Equipment Costs 21.85
Onsite Startup and Fixed Costs
Mobilization.transportation to and from site 0.37
assembly 0.74
Shakedown and testing 1.16
Contingency 2.20
Total Startup and Fixed Costs 4.47
Labor Costs
Feed operators 25.51
Maintenance mechanic 30.61
System operator 81.64
Engineering/Supervisor 25.51
Total Labor Costs 163.27
Supplies Costs
Isopar-L <5>$1.50/gal 8.90
Total Supplies Costs 8.90
Consumables Costs
Cooling water 0.44
Fuel (steam) 7.35
Nitrogen 5.84
Electricity 1.73'
Total Consumables Costs 15.36
Effluent Treatment and Disposal Costs
Non-contact cooling water
Total Effluent Treatment and Disposal Costs
Residuals & Waste Shipping, Handling, & Transport Costs
Waste disposal (incineration @ $200/drum) 239.64
Onsite facility costs
(backfill solids on site) 7.23
Offsite facility costs
(wastewater disposal at POTW) 0.15
Total Residuals & Waste Shipping,
& Transport Costs 247.02
Analytical Costs
Operations
Environmental monitoring
Total Analytical Costs
Equipment Repair & Replacement Costs
Design adjustments
Facility modifications
Scheduled maintenance
Equipment replacement
Total Equipment Repair & •»
Replacement Costs
Site Demobilization Costs
Disassembly
Site cleanup and restoration
Permanent storage
Total Site Demobilization Costs
Total Operating Costs ($/TON)
4.79
4.79
2.78
2.78
523.44
4.2.1 Site Preparation Costs
Site preparation costs include access rights, site layout,
legal searches, roads, utility connections, and excavation and
pretreatment of waste. This cost analysis assumes that pre-
liminary site preparation will be performed by the responsible
party. Site preparation costs will vary depending on the type,
condition, and geographical location of the site. Sites where
excavation is difficult will have significantly increased site
preparation costs. Also, waste requiring extensive pretreat-
ment will increase costs in this category.
Estimates for site preparation are based on an excavation
rate of about 1.2 yd3/hr. Minimum requirements are one
backhoe, available for $4,000/mo, one supervisor at $40/hr,
and one excavator operator at $30/hr, yielding an excavation
cost of about $55/ton (Means, 1991). For the purposes of this
cost analysis, it is assumed that excavation will occur con-
currently with waste treatment Pretreatment costs involve
operation of screening equipment and are included in equip-
ment operating costs of the C-G Process equipment, Section
4.2.5.
4.22 Permitting and Regulatory Costs
Permitting and regulatory costs depend on whether treat-
ment is performed on a Superfund or a RCRA corrective
action site and on the fate of the treated waste. Section 121(d)
of CERCLA, as amended by SARA, requires that remedial
actions be consistent with ARARs of environmental laws,
ordinances, regulations, and statutes. ARARs include federal
standards, as well as more stringent state or local standards.
ARARs must be determined on a site-specific basis. Because
permitting costs can vary greatly depending on the site, they
are not included in this analysis.
4.2.3 Capital Equipment Costs
Capital equipment costs include the cost of the trailer-
mounted C-G Process unit and the auxiliary equipment, which
includes a distillation column and screening equipment. Total
equipment costs are estimated at $1.3 million. The capital
costs shown in Table 4-1 are based on information provided
by Dehydro-Tech and assume financing at 7%/yr over 10 yr.
4.2.4 Startup and Fixed Costs
Startup and fixed costs include mobilization, crane rental,
and labor expenses for assembly and shakedown of the sys-
tem. Mobilization includes both transportation and assembly.
16
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Transportation costs are based on transporting three trailers.
A 1000-mile basis is assumed, with a $4,000 permit fee for
one oversize trailer, with an overall transportation cost of
$1.50/mile. The C-G Process requires a 5-ton crane to lift the
vertical evaporator into place. Crane rental costs include an
operator and are estimated at $2,000/wk for two wk. Shake-
down operations involve testing each major unit operation
(evaporation, centrifugation, and deoiling), and establishing
operating parameters for the waste stream; these costs would
primarily consist of labor charges, and are estimated at $ 12,800.
Onsite startup costs are based on one month of labor costs
for four persons at $40/hr, plus travel and living expenses, and
total about $100,000, including contingency. Contingency
costs include unforeseen events, such as additional time to
optimize the process operation for a particular waste stream,
and are estimated at $50,000. Actual startup costs would vary
with site conditions and include factors such as available land
and utility connections.
4.2.5 Labor Costs
Labor costs are based on the following: one feed operator
at $25/hr (three shifts/day), two system operators at $40/hr
(three shifts/day), one maintenance mechanic at $30/hr (three
shifts/day), and one engineer/supervisor at $75/hr (one shift/
day). The feed operator operates screening equipment and the
feed hopper. Rates include overhead and administrative costs.
Existing C-G Process units use local personnel for all system
operations. It is therefore assumed that after startup and
shakedown is complete, local workers will operate the unit.
4.2.6 Supplies Costs
Supplies consist of Isopar-L, the carrier solvent. Based
on data from ongoing operations and from the demonstration,
about 6 gal/ton of feed (8.3 gal/hr) of Isopar-L will require
replacement due to losses in the bottoms of the distillation
operation. This results in a total cost of about $202,000, or
$8.90/ton. However, this cost depends on the oil content of
the waste, the physical properties of the organic contaminants
and the efficiency of the distillation operation.
4.2.7 Consumables Costs
Consumables costs include costs for cooling water, steam,
nitrogen, and electricity. The quantities used depend on the
waste feed rate, the water content of the waste, and the scale
of operation. In this analysis, bulk pricing for steam is
estimated at $5 per million British Thermal Units (Btu).
Based on operating data from existing operating units, the C-
G Process plant is estimated to use about 1.47 million Btu per
ton of waste, resulting in a unit cost for steam of $7.35/ton.
The cooling water systems used by full-scale C-G Pro-
cess plants are closed-loop, limiting water costs to the operat-
ing costs of an onsite cooling tower. These costs are based on
using a 205-gal/min tower, and are estimated at $0.05/ 1,000
gal, or $0.44/ton.
The C-G Process uses nitrogen in deoiling operations.
Nitrogen consumption depends on the levels of residual oil
required in the final solids product, and may depend on local
requirements at a particular site. Nitrogen use is estimated at
about 1,620 standard ftVhr (SCFH). A nitrogen cost of $5/
thousand ft3 results in a unit cost of $5.84/ton.
The C-G Process unit requires 480-volt, three-phase elec-
tric power. The electric power requirements are primarily for
motors, pumps, and the centrifuge in the system. With a
usage rate of about 40 kilowatts and a cost of electricity of
$0.06 per kilowatt-hour, unit cost for electric power is $1.73/
.ton.
4.2.8 Effluent Treatment and Disposal Costs
The full-scale C-G Process unit uses a completely closed
system to circulate non-contact cooling water. As stated
earlier, the cooling water used in a full-scale remediation
would be pumped through an onsite cooling tower and would
require very little makeup. Therefore, disposal costs for this
stream are insignificant and are not included in this cost
analysis.
4.2.9 Residuals Shipping, Handling, and
Transportation Costs
During the demonstration, the C-G Process unit produced
three residual streams: a dry solids product, a water stream,
and an oil phase, consisting of a mixture of the Isopar-L and
indigenous organic wastes.
The dry solids product passed TCLP criteria and exhib-
ited very low levels of petroleum hydrocarbons. Therefore,
disposal costs are based on backfilling this material at the site,
at a cost of $15/ton. If, however, solid residues must be
disposed of at an off-site landfill, costs will increase to about
$45/ton. This cost reflects transportation, disposal, and other
customary charges for offsite disposal in a sanitary landfill
within 100 miles of the waste site.
Disposal costs of residual water from waste treatment are
based on disposal of about 1.6 million gal of water to a local
POTW. Total water disposal costs are estimated at $2/1000
gal, resulting in a unit cost of $0.15/ton of waste.
Residual oil disposal includes the original volume of
Isopar-L carrier solvent, all makeup solvent, and all indig-
enous oils from the waste. The total volume of oily waste is
estimated at 1.52 million gal. Disposal costs are based on a
unit cost for transportation and incineration of $200/55-gal
drum, resulting in a unit cost of about $240/ton of waste
treated.
4.2.10 Analytical Costs
Analytical costs include those for laboratory analysis,
data reduction and tabulation, QA/QC, and reporting. These
costs are for verification of treatment effectiveness and do not
include waste characterization. Analytical costs will vary
according to the types of contaminants and regulatory require-
ments for the waste and therefore are not included in this cost
analysis.
17
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Equipment Repair and Replacement
4.2.11
Costs
During operation, some parts of the unit may require
repair or replacement. For this analysis, annual equipment
repair and replacement costs are assumed to be about 3% of
capital costs, or $4.79/ton.
4.2.12 Site Demobilization Costs
Site demobilization normally includes items such as op-
eration shutdown and decommissioning of equipment and
disconnection of utilities. This analysis bases demobilization
costs only on disassembly of process equipment, and are
estimated at $2.78/ton. Transportation costs are included in
the mobilization category. Disassembly consists of lowering
the vertical falling-film evaporator with a crane. Crane rental
costs are estimated at $2,000/wk for two wk.
4.3 Summary of Economic Analysis
Considering the 12 cost categories and the assumptions
made in this economic analysis, the estimated cost per ton for
treating drilling mud wastes at 1.4 tons/hr is'$523/ton. This
cost includes pretreatment, startup, capital, operating, and
residual disposal costs for a C-G Process mobile unit treating
waste at a Superfund site similar to the PAB Oil site with an
on-line factor of 70%. Of the $523 per wet ton cost, $221 is
C-G Process-specific and $302 is site-specific. Of the $302
per ton site-specific cost, about $240 is for the incineration of
indigenous oil separated from the feed. Variations in the on-
line factor increases technology-specific costs only. An on-
line factor of 60% results in a unit cost of $560/ton, while a
50% on-line factor increases the cost to $61 I/ton.
As mentioned earlier, costs presented in this analysis are
order-of-magnitude estimates (-30% to +50%) and are rounded
to the nearest dollar. Also, factors that affect the estimated
cost of the C-G Process unit are highly site-specific. Variabil-
ity in site and waste characteristics and in residual transporta-
tion and disposal costs could significantly affect the costs
presented in this economic analysis.
References
Dehydro-Tech Corporation (DTC), 1989. The Carver-
Greenfield Process, a proposal in response to U.S. EPA RFP-
004.
Federal Register, 1990. National Oil and Hazardous
Substances Contingency Plan; Final Rule, Volume 55, No. 46,
March 8.
R.S. Means Company, Inc. (Means), 1991. Means Site
Work Cost Data, 10th Annual Edition, Construction Consult-
ants and Publishers, Kingston, MA.
PRC Environmental Management, Inc. (PRC), 1991.
Demonstration Plan for the Carver-Greenfield Process, U.S.
EPA SITE Program (May).
U.S. Environmental Protection Agency (U.S. EPA), 1989a.
Superfund LDR Guide #1, Overview of RCRA Land Disposal
Restrictions (LDRs), U.S. EPA Directive 9346.3-01FS.
U.S. EPA, 1989b. CERCLA Compliance with Other
Laws Manual: Part II. Clean Air Act and Other Environmen-
tal Statutes and State Requirements, (Interim Final), OSWER
Directive 9234.1-02.
U.S. EPA, 1992. Technology Evaluation Report. SITE
Program Demonstration of the Dehydro-Tech Corporation
Carver-Greenfield Process, EPA/540/XX-92/XXXX (to be
published).
18
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Appendix A
Carver-Greenfield Process Description
A.I Background
The primary purpose of the C-G Process is to separate
multi-phase mixtures into their respective solids, indigenous
oil, and water fractions. The process is based on suspending
solids containing water and oils in a "carrier" oil or solvent.
This solvent keeps the viscosity of the mixture low, permits
high heat transfer rates, and prevents scaling or fouling of heat
transfer surfaces as the water in the mixture evaporates. The
resultant product solids are virtually water-free (<5% by
weight). Organics indigenous to the materials processed are
extracted by the carrier solvent. In the demonstration, these
consisted of petroleum-based hydrocarbons and other oil-
soluble organics. Thus, the separation process produces dry
solids, from which the indigenous oils and organics have been
extracted.
A.2 The Carver-Greenfield Process System
The C-G Process involves slurrying the feed material
with a carrier solvent; evaporating water from the slurry in a
high-efficiency multi-effect evaporator; separating the solvent
from the feed solids in a centrifuge; and evaporating the
solvent from the solids., The used carrier solvent is distilled to
separate the indigenous oils and organics and to recover
reusable solvent Residuals (products) from the process include
(1) a concentrated mixture of the extracted indigenous oil and
organics, (2) water substantially free of solids and oils, and (3)
clean, dry solids. The following sections briefly describe the
major unit operations in the C-G Process, as shown in the
general schematic flowsheet for commercial systems (Figure
A-l). First, the process is described as it would be applied on
a commercial scale. The final section discusses application on
a pilot scale.
A.2.1 Slurrying
The first step involves slurrying the feedstock with a
solvent The particular solvent used depends on the applica-
tion and the disposal method for the extracted materials.
Generally, a hydrocarbon-based solvent with a narrow boiling
range around 400 °F is used for hydrocarbon or organically
contaminated solids. Five to ten Ib of solvent/lb of waste
solids is typically needed for slurrying. Any dense'debris in
the feed is first separated; if necessary, the feed solids are
ground to particle sizes of less than 1/4-in. The feed charac-
teristics and the process objective generally determine the
solvent-to-waste solids ratio. Higher ratios promote fluidiza-
tion for easy transfer of the slurry and increase efficiencies for
extracting soluble organics into the solvent.
A.2.2 Evaporation!Heat Exchange
The solvent/feed slurry is circulated through an energy
efficient single or multi-effect evaporator system to remove
the water. The solvent is thoroughly mixed with the solids to
achieve extraction of indigenous oils (including petroleum
based oils) and solvent soluble organic compounds. The
multi-effect evaporation is counter-current to the fluid slurry
and the steam. For example, in the two-effect evaporator
shown in Figure A-l, steam from a boiler heats the recirculating
slurry in the second effect (at about 250,°F, under slight
vacuum). Steam from the recirculating stream leaves the
second effect at a lower temperature (212 °F) and heats the
recirculating slurry in the first effect, which operates under
higher vacuum, thereby reducing the boiling point of water.
Because of the lower boiling points, heat from the steam can
be reused. Thus significantly greater amounts of water can be
evaporated per unit of boiler steam, in a multi-effect system.
Process design and operation typically removes equal amounts
of water in each effect. The number of effects in the evaporator
system depends on the slurry characteristics and water content.
Generally, commercial systems have two to four effects.
The evaporation step can enhance organics extraction
efficiency by breaking up emulsions holding the compounds
in the solids. In addition, volatile compounds in the feed are
stripped in this step and are condensed with the vaporized
water and small quantities of solvent. Any pathogens or
microorganisms in the feed are also destroyed by the heat,
yielding a sterile final product.
A.2.3 Centrifuging
The slurry is sent to a centrifuge from the evaporation
section to separate most of the solvent from the solids. The
solids are then either reslurried with clean (recirculated) sol-
vent for additional extractions or treated to remove residual
solvent The centrifuge cake is typically about 50% solvent or
greater (with extracted organics) and 50% solids. The centrate
will essentially be the solvent with extracted indigenous oil
and organics and less than 1% solids (fines). The solvent may
be recycled after separating the solvent from the indigenous
organics by distillation.
A.2.4 Desolventization
After final centrifuging, residual solvent is removed from
the solids by desolventization. This process relies on evapo-
ration and gas stripping to separate the solvent from the solids.
The heated stripping gas (such as nitrogen or steam) is scrubbed
19.
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Feed Preparation
Vacuum
Multi-Effect Evaporation
Solids/Oil Separation
Fluid/zing Solvent Vapor and Steam
Descol Ventlzer
Recovered Solvent
Fluldlzlng
Solvent
Makeup
Water-Oil-Solvent
Separator clean
Water
., I Indigenous
(Sludge)
on
Stripper Deolled
Dry
Sterile
Solids
Condensate/OII Separation
Figure A-1. General process schematic for commercial C-G systems.
Oil Recovery/Steam Generation
(of solvent vapor) and recirculated to the desolventizer. The
final dry solids product is clean and typically contains less
than 3% water. The residual oil and indigenous organics
levels in the solids depends on extraction efficiency, the
number of extractions, and the initial levels in the feed. The
desolventizer will not evaporate most of the heavy indigenous
oils remaining in the centrifuge cake; these remain with the
solids fraction.
A..2.5 Distillation
Fractional distillation separates extracted impurities from
the solvent, producing a recovered solvent substantially free
from impurities and a concentrated stream of extracted "light"
and "heavy" organics (relative to the boiling point of the
solvent). The recovered solvent is reused in the slurrying
process. The concentrated streams of extracted indigenous
oils and organics can either be incinerated (for example, in the
boiler as shown in Figure A-1) or reclaimed.
A.2.6 Oil/Water Separator
The water removed from the slurry in the evaporation
step is collected in a decanter after condensation. Water-
immiscible solvent condensed with the evaporated water is
removed, leaving relatively clean water, virtually free of
solids, with a low residual solvent content. It may contain
low-boiling water-soluble compounds extracted from the feed
waste and can typically be treated with standard wastewater
treatment technologies, either onsite or at an offsite treatment
plant Treatment options will depend on the characteristics of
the feed waste.
A.2.7 Vent Gases
All unit operations are closed, and the vent gases are
collected in a single stream. The major sources of vent gas are
the evaporation section and the desolventizer, but losses are
small due to high efficiency condensers. The vents are treated
for residual organics reduction by passing the gas through
granular activated carbon canisters.
A.2.8 Pilot Scale Applications
Commercial-scale systems normally operate continuously.
The mobile pilot unit used in the SITE demonstration differed
in several aspects from the commercial system:
• A single-effect evaporation step was used for drying,
and extraction was done on a batch basis.
20
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• The distillation step for separation and recovery of the
solvent was not performed because DTC did not have
pilot-scale distillation equipment at the time of the
demonstration. Commercial systems have a separate,
dedicated multi-stage distillation operation. Fresh sol-
vent was used for each evaporation and extraction.
• Nitrogen was used as the stripping gas for the
desolventizer operation, and would be recommended
for most commercial operations.
The C-G Process was first commercialized in 1961. Since
then it has been licensed in over 80 plants around the world to
dry municipal and industrial sludges and other biomass wastes.
Three commercial municipal sludge plants are operating in
Japan, treating municipal and industrial primary and waste
activated sludges and night soil with solids contents of 4.5%
and higher. In the United States, the City of Los Angeles
operates one C-G Process plant. Two other similar municipal
sludge facilities are under construction. Another municipal
sludge facility in Ocean County, NJ is producing fertilizer.
In recent years Dehydro-Tech Corporation (DTC), the
sole licensor of the C-G Process, has conducted a number of
pilot plant studies to establish whether the C-G Process is
suitable for processing petroleum sludges and other industrial
wastes at appropriate Superfund sites. Results of this work is
summarized in Appendix D.
In 1984, waste samples from an oil refinery were treated
in the C-G Process pilot plant in East Hanover, NJ. The waste
samples were from DAF sludge, API separator bottoms, tank
bottoms, bio-sludge, and primary/secondary emulsions. The
waste samples were mixed in different proportions to produce
three feed mixtures. Starting with feed materials having a
high indigenous oil-to-solid ratio (in the range of 25 to 40),
the C-G Process produced solids containing only 3.8% to
5.4% indigenous oil. The hazardous compounds originally
present in the feed materials, such as benzene and phenol,
were also removed from the solids.
In 1985, DTC used the C-G Process to treat slop oil
samples from an oil company's wastewater pond. The slop oil
sample was successfully separated into its solid, water and oil-
soluble (indigenous oil) products at the pilot plant in East
Hanover, NJ. The original slop oil was unsuitable for
landfilling due to hazardous compounds, such as benzene,
toluene and chromium. Test results for final solid products
revealed that the final dry product met all the requirements for
non-hazardous landfilling, as specified by EPA.
References
PRC, 1991. Demonstration Plan for the Carver-Greenfield
SITE Demonstration Program Report (June).
21
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Appendix B
Vendor's Claims for Carver-Greenfield
Process Technology
B.I Introduction
The patented Carver-Greenfield (C-G) Process® repre-
sents an important new approach to remediating soils, petro-
leum K-wastes, spent drilling muds, and other hazardous
sludges containing petroleum-based contaminants, such as
fuel oils, PCBs, and polynuclear aromatics (PNAs). The
process is well-proven and has been used extensively over the
past 30 yr to dry and extract compounds from a variety of wet,
oily solids. The C-G Process™ can efficiently separate oily
soils and sludges into three products for final disposition: (1)
indigenous oil compounds, (2) evaporated water, and (3) dry,
decontaminated soil.
Dehydro-Tech Corporation (DTC) has licensed over 80
C-G Process facilities worldwide over the past 30 yr to solve
waste disposal problems in a variety of fields. 53 of these*
licensed facilities are designed to dry and deoil slaughter-
house wastes (from rendering plants). The other plants are
designed to evaporate water and extract indigenous oil from a
broad spectrum of materials, including municipal and indus-
trial sewage sludges, wool scouring wastes, petrochemical
sludges, wood pulp wastes, pharmaceutical wastes, dairy and
food products, textile and dye wastes, animal manure, etc.
Growing environmental concerns have accelerated the demand
for the technology in recent years, as indicated by the increase
in cumulative licensed capacity shown in Figure B-l.
Many of the current applications of the C-G Process have
processing requirements very similar to ofly soil and sludge
treatment For example, dewatered municipal sewage sludge
typically contains over 20% solids and has a high ash ("sand")
content. Commercial C-G Process plants extract and recover
the indigenous sewage oil (which represents about 10 weight
percent of the total solids) and dry the solids to less than 5%
moisture.
B.2 Process Description
A simplified process flow diagram of a commercial de-
sign including 3 extraction stages is shown in Figure B-2. As
a first step, the pre-screened oily soil and sludge are fed to a
water evaporation section, where they are mixed with a water-
immiscible solvent to form a slurry. Different types of solvents
are used, depending upon the feed properties and desired
product characteristics. For soil remediation applications,
alcohols or food-grade mineral oils having a boiling point of
about 400 °F are typically used.
In the evaporation section, the water in the feed is evapo-
rated from the slurry and the first stage of extraction takes
place. In addition to extracting contaminants from the solids,
the solvent fluidizes the solids and ensures a low slurry
viscosity as the solids become dry. The solvent also prevents
scaling and fouling of the heating surfaces, thereby ensuring
good heat transfer. By evaporating the water, problems with
emulsions are avoided, even with "difficult-to-process" feeds.
The vapors leaving the evaporation section are condensed
and any water-immiscible solvent present is easily decanted
from the water. The solvent containing extracted oil leaves
the first stage of extraction and is separated from the extracted
oily contaminants in a distillation column. The concentrated
recovered oil is removed for disposal. The clean, distilled
solvent is recycled to the third stage of extraction.
The solids leaving the evaporation section are fed to two
additional stages of countercurrent extraction to achieve a
higher degree of decontamination. The residual solvent left
on the solids after the third extraction is recovered by heating
and purging the solids with steam or nitrogen
("desolventizing").
Capacity (Dry Tons per Day)
200 _
64 66 68 70
78 80 82 84 86 88 90 91
Year of Startup
Figure B-1. C-G process licensed capacity.
23
-------
Evaporation
1st Solvent
Extraction
Treated
Solids
Figure B-2. C-G process block flow diagram.
Each of the three products generated when treating oily
soils and sludges with the C-G Process are in a form that is
convenient for final disposition. In many cases, the solids are
decontaminated and can be landfilled. If the treated solids
still contain unacceptable levels of inorganic compounds,
such as heavy metals, this reduced volume of waste can be
chemically "fixed" to make the metals non-leachable. Re-
moval of the petroleum contaminants greatly improves the
effectiveness of chemical fixation techniques. The extracted
oil-soluble compounds can be refined and reused or, alterna-
tively, burned to destroy the hazardous compounds and/or to
produce steam. The evaporated water recovered from the feed
can usually be sent directly to a wastewater treatment plant
Particle Size of Processed PAB Oil Site Solids
The particle size analysis of the product solids from the
C-G Process demonstration on the PAB Oil Site material
reveals that the process can treat solids having smaller particle
sizes than have been typically capable of being handled by
conventional soil washing techniques. Table B-l summarizes
the particle sizes analyzed by laser light scattering
(MICROTRAC).
The data from Table B-l has also been plotted on Figure
B-3 as superimposed curves on Figure 1. Soil Washing Appli-
cable Particle Size Range (EPA/540/2-90/017, 9/90, Engi-
neering Bulletin: Soil Washing Treatment). The plot of the
ultimate particle sizes fall within the "Difficult Soil Washing
Regime (HI)" while the agglomerated particles are barely
within the "Soil Wash with Specific Washing Fluid Regime
(II)". This shows that the C-G Process has been demonstrated
to be capable of processing materials which have been shown
heretofore to be difficult or impossible to process using pres-
ently developed soil washing techniques.
Table B-1. Particle Size Analyses-Product Solids-PAB Oil Site
Particle Size,
microns
704
498
352
249
176
125
88
62
44
31
22
15
11
8
6
4
3
2
1
Ultimate Particles,
% Passing
—
—
100.0
99.8
98.8
97.3
94.7
89.2
79.9
68.4
57.0
48.0
40.8
36.6
20.7
9.3
1.3
0.0
Agglomerated Particles,
% Passing
100.0
• 89.0
78.5
70.2
63.7
58.1
53.3
46.8
• 40.8
34.9
27.9
21.5
16.6
12.9
9.8
6.6
4.3
2.1
0.8
Average Size
12.0 Microns
73.4 Microns
24
-------
Gravel
Average
Ultimate Particles
Agglomerated Particles
Difficult
Soil Washing
(Regime III)
Soil Wash with
Specific Washing Fluid
(Regime II)
Economic Wash
with Simple Particle
Size Separation
(Regime I)
0.001 0.002 0.006 0.01 0.02
0.063 0.1 0.2 0.6 1
Diameter of Particle in Millimeters
10 20
50 100
Figure B-3. Particle size distributions of C-G processed solids from PAB Oil Site.
B.3 Process Economics
Table B-2 shows the estimated economics for a commer-
cial C-G Process plant designed to remediate the PAB Oil site
in about 2.7 years. The plant can treat 2,771 Ib/hr of spent
contaminated soil and spent drilling muds with the following
composition:
Component
Water
Indigenous Oil
Solids
Total
Weight Percent
31.0
17.0
52.0
100.0
An overall material balance is given at the bottom of
Table B-2. With an assumed on-stream factor of 67%, this
plant can treat 8,132 tons/yr. Based on a preliminary equip-
ment list, it was estimated that it would cost about $1,300,000
to install the battery-limits equipment. An initial solvent
charge would cost about $15,000. The overall cost of $173,4297
yr for utilities and chemicals reflects the 67% on-stream
factor.
Project Economics for the PAB Oil Site
Table B-3 presents the Base Case Economics and 4
sensitivity cases for processing 23,000 tons of PAB Oil Site
material having the composition shown above. Costs are
based on the EPA's 12 "standard" cost categories presented in
Section 4 of the main body of this report. Appropriate
comments are given below on the individual cost categories as
related to the C-G Process.
The 4 sensitivity cases include:
Case 1. On-stream factor of 0.5 vs. 0.7 in Base Case.
Case 2. $0/Bbl credit for residual oil vs. $20/Bbl in Base
Case.
Case 3. Capacity of 1.88 tons/hr feed vs. 1.4 tons/hr in
Base Case (higher investment, shorter processing
time).
Case 4. Capacity of 2.5 tons/hr feed vs. 1.4 tons/hr in Base
Case (higher investment, shorter processing time).
There are also two distinctive classifications into which
the 12 cost categories fall; technology specific, and site specific.
Table B-3 divides the 12 cost categories into these two
classifications. While there may be some discussion on which
costs are technology and site specific and, in fact, some
components of a particular cost category could fall into both
for a given technology/project, in this case they have been
allocated according to their presentation by the EPA in Sec-
tion 4 (Table 4-1) of this report.
Technology Specific costs are those relating to the par-
ticular technology being evaluated and would be incurred
while treating the specific feed regardless of where the treat-
ment were taking place. By considering the technology
specific costs only, the costs under the control of the technology
developer can be itemized and a more valid comparison can
be made between competing processes.
Site Specific costs are; those relating to a specific site and
would be incurred independently of which technology were
used for remediation.
The following paragraphs discuss the bases and other
considerations of the 12 cost categories included in the evalu-
ation of the C-G process for the SITE Program.
25
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Tablo B-2. Estimate* for Carver-Greenfield Process Plant
Basis • •
Assumes Installation of battery-limits equipment on trailers on September 1991 and operation of plant at a clear and level site in the US.
Assumes a conservative *on-stream" factor of 67%. Does not include feed excavation, recovered water treatment, recovered oil disposal, or
solids storage/transportation. Initial costs do not include facilities for utility supply.
Initial Costs • •
Installed Equipment Cost $1,300,000
Initial Solvent Charge $15,000
Initial Cost $1,315,000
Utilities and Chemicals
Steam (250 psig)
Power
Cooling Water
Makeup Solvent
Makeup Nitrogen
Quantities
1.54 Mil BTU/hr
37KW
205gal/min
8.3gaVhr
1620 SCFH
Unit Costs
4$/MilBTU
6 cents/KWH
5 cents/k gal
1.5$/gal
5$/MSCF
$/hr
6.16
2.22
0.61
12.45
8.10
29.55
Operating Costs
$Aon feed
4.43
1.60
0.44
8.96
5.83
21.26
$/vr
36,159
13,031
3,610
73,082
47,547
173,429
Material Balance (Ib/hr)
Water
Indigenous Oil
Solids
Solvent
Nitrogen
Total
Feed
859
471
1441
0
&
2771
Makeups
0
0
0
55
122
775
Treated
Solids
13
9
1301
13
Q.
1336
Evap.
Water
838
0
0
1
Q.
839
Recov.
Oil
0
462
140
40
a.
642
Vent
8
0
0
1
m
129
3/2/92
4.2.1. Site Preparation (Site Specific) Costs which in-
clude excavation at a cost of $75.55/hr when operating at
design rates was calculated by the EPA (Table 4-1). It is
assumed that the quantities handled are relatively small for the
equipment required so that the feed for the higher capacity
cases can be processed at the higher rates at the same hourly
cost as in the Base Case so savings are realized because of the
shorter processing time.
4.2.2. Permitting and Regulatory (Site Specific) Costs
vary greatly depending on the site and consequently the EPA
and DTC have chosen not to include them in this evaluation.
4.2.3. Equipment (Technology Specific) Costs are based
on a the capital requirements for the C-G Process unit (1.3 M$
for the Base Case) and per the EPA should be amortized at
7%/yr over 10 yr, i.e. the equivalent of paying back the
principal and interest on a mortgage over a 10-yr period. At
the level of plant capacity considered here the investment cost
is scaled at the 0.5 power of capacity.
4.2.4. Start-up and Fixed (Technology Specific) Costs are
based on estimates of transportation, mobilization, and start-
up expenses for the processing unit and are considered based
on a one-month time period to accomplish this. The estimated
EPA costs of 126 k$ are used in Table B-3. It is assumed that
these costs are independent of capacity so are the same for all
cases.
4.2.5. Labor (Technology Specific) Costs are based on
DTC manning and labor cost estimates which would require 1
feed operator ($40/hr, 3 shifts/day), 1 system operator ($40/hr
each, 3 shifts/day), 1 maintenance mechanic ($40/hr, 1 shift/
day), and 1 halftime supervisor (not necessarily onsite; $60/
hr, 1 shift/day). It is projected that the same manning is
required for the equipment in the higher capacity cases so that
savings are realized in these cases because of the shorter
processing times.
4.2.6. Supplies (Technology Specific) Costs for the C-G
Process include only the cost of the Isopar-L solvent and since
the make-up solvent requirement is calculated based on a per
ton of feed basis, the cost is constant at all capacities.
4.2.7. Consumables (Technology Specific) Costs are the
utility costs for the C-G plant operation. As with the supplies
category above, since the consumable requirements are cal-
culated on a per ton of feed basis, the cost is constant at all
capacities. Note that while the heat requirements are given in
terms of steam in Table B-2, EPA has chosen to define the
heating medium as natural gas. On this basis it is assumed
that natural gas is fired at 75% efficiency to make steam and
the heating requirement based on steam has been increased
accordingly to reflect this basis on Table B-3.
4.2.8. Effluent Treatment and Disposal (Site Specific)
Costs are considered to be insignificant by the EPA and are
not included here.
26
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Table B-3. C-G Process- Economic Sensitivity Cases- PAB OH Site
Base Case Case 1 Case 2(1)
Feed Tons 23000
On-Stream Factor 0.7
Design Hourly Rate, Feed Tons/hr 1.4
Daily Rate, Feed Tons/day 33.6
Elapsed Time, Days 977.9
Years 2.68
Estimated Investment, $M 1.3
Base Case
Cost Category Calc
Site(S)/Technology(T) Specific Basis
4.2.1 Site Preparation/S 75.55 $/hr
Excavation
4.2.3 EquipmenVT 1.3M$
4.2.4 Start-up and Fixed/T 126k$
4.2.5 Labor/T
Feed'Operator 1 0perator
Maintenance Mechanic . 1 Mechanic
System Operator 2 Operator
Supervision 0.5 Position
Total
4.2.6 Supplies/T, Isopar-L 5.93 gal/ton
4.2.7 Consumables/T
Cooling Water 8.79kgal/Ton
Fuel (steam) 1.47 MBtu/Ton
Nitrogen 1 160 SCF/Ton
Electricity 28.6 kwh/Ton
Total
4.2.8 Effluent Treatment & Disposal/S
4.2.9 Residuals Treatment, etc./S
Oil 1.56Bbl/Ton
Solids 0.482 Ton/Ton
Water 72.2 gal/ton
Total
4.2. 10 Analyticals/S
4.2.11 Facility Maintenance/T 1.3M$
4.2.12 Demobilization/S 63 k$
Total Operating Costs($ Ton Feed)
Site Specific Operating Cost ($/Ton Feed)
Technology Specific Operating Costs
23000 23000
0.5 0.7
1.4 1.4
33.6 33.6
1369.1 977.9
3.75 2.68
1.3 1.3
Base Case
Unit
Cost/Basis
1.4 Tons/hr 53.96 . 53.96
7%/Yr amort 21.56 30.18
10 Yrlife
23000 Tons 5.48 5.48
40$/hr,3S/D
40$/hr,1S/D
40$/hr,3S/D
60$/hr,1S/D
105.44 147.62
1.5$/gal 8.90 8.90
0.05 $/kgal
5$/MBtu
5$/kSCF
0.06$/kwh
15.31 15.31
r
20 $/Bbl Credit
15$/Ton
• 2$/kgal
-23.90 -23.90
3% Inv/yr 4.54 6.36
23000 Tons 2.74 2.74
194:03 246.65
30.06 30.06
163.97 216.59
CaseS
23000
0.7
1.88
45.12
730
2
1.51
$/Ton Feed
53.96
21.56
5.48
105.44
8.90
15.31
7.30 ;
4.54
2.74
225.23
61.26
163.97
Case 4
23000
0.7
2.5
60
547
1.5
1.74
•
40. 19
18.65
5.48
78.52
8.90
15.31
-23.90
3.93
2.74
149.82
16.29
133.53
30.22
16.16
5.48
59.05
8.90
15.31
-23.90
3.41
2.74
117.37
6.32
111.05
($/Ton Feed)
(1) Case 2 assumes no credit for Residual Oil sale vs. $20/Bbl (42 gal) credit in other cases.
4/15/92
4.2.9. Residuals Treatment (Site Specific) Costs although
classified as site specific are illustrative of the advantage of
the C-G Process technology for this type of site remediation:
The clean water separated using the C-G Process can be
processed in a POTW at a cost of $2.00/$k gal vs the cost for
processing some contaminated waters separately which can
be significantly higher.
The clean solids at reduced volume (in this case about 0.5
ton/ton feed) can be landfilled at $15/ton clean solids or about
$7.50/ton feed vs. contaminated feed material at $45/ton feed
(per EPA) or more depending on its hazardous characteristics
(see below).
The separated residual indigenous oil, containing trace
amounts of solvent but for the PAB Oil Site containing no
27
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hazardous contaminants, can be sold to an oil refinery for a
credit. For the Base Case and 3 Sensitivity cases it was
assumed to be sold at a crude oil value of $20/Bbl (42 gal/
Bbl), $31.20/ton feed, so that the net treatment cost for all the
residuals is a credit of $23.90/ton feed. If the residual oil is
disposed of at no cost/no credit (Case 2) the cost of residual
treatment is $7.30/ton feed. Contrast these costs with hazard-
ous materials disposal estimates for incineration at $200/55
gallon drum used in Table 4-1 which includes $240/ton of
feed for incineration of the indigenous oil alone or $880/ton
(4.4 drums/ton feed) if the total drilling mud waste feed were
incinerated.
4.2.10. Analytical (Site Specific) Costs are site specific
and for this reason EPA and DTC have chosen not to include
them.
4.2.11. Faculty Maintenance (Technology Specific) Costs
are normally investment related on an annual basis and a
typical level of 3% Inv/yr has been chosen by EPA and DTC.
These costs vary both with investment level and time required
for processing.
4.2.12. Demobilization (Technology Specific) Costs have
been proposed by DTC to be about half of the Start-up and
Fixed Costs and are shown on this basis in Table B-3.
The following ranges of operating costs are shown on
Tables B-3 and 4-1:
Base Case Sensitivity Table 4-1
$/ton feed Case Range, Base Case
Technology Specific 164 111-216 221
Costs
Site Specific Costs 30 6-61 302
Total Costs 194 117-247 523
From the above it is concluded that C-G Process technol-
ogy specific costs are typically in the range of $100-220/ton of
drilling mud waste feed and would be expected to be compa-
rable for similar feeds. Site specific costs, which include the
cost of residuals disposal, range from minimal (<$10/ton) to
more than $300/ton of drilling mud waste feed and in the cases
presented here are very sensitive to the assumed residuals
disposition and associated costs or credits.
28
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Appendix C
Carver-Greenfield SITE
Demonstration Test Results
This appendix summarizes the Dehydro-Tech
Corporation's (DTC) Carver-Greenfield (C-G) Process SITE
demonstration. A detailed presentation of the SITE demon-
stration results can be found in the Technology Evaluation
Report. The SITE demonstration was conducted at an EPA
research facility in Edison, NJ, using drilling mud wastes
from the PAB Oil and Chemical Services (PAD Oil) Superfund
site in Abbeville, LA. The waste was transported to EPA's
Edison, NJ research facility and was processed over a three-
week period. The resulting residuals included concentrated
oils, water, and a nonhazardous solids product.
C.1 The PAB Oil Site
The PAB Oil site is located in Vermilion Parish, LA, on
about 16.7 acres of property adjacent to Highway 167, north
of Abbeville. PAB Oil began operation in 1979 under provi-
sions of a permit issued September 25,1979, by the Louisiana
Department of Natural Resources, Office of Conservation. It
received and disposed of oil-field drilling mud wastes and salt
water generated from oil and gas well operations.
On July 20,1980, an amendment to Statewide Order 29-
B became effective, establishing new requirements for offsite
drilling mud and salt water disposal facilities. Existing facilities
were granted temporary authority to operate, with 90 days to
comply with the new requirements. PAB Oil reported that it
stopped receiving oil-field wastes in August 1982 because of
its inability to meet the new requirements. Its interim authority
to operate the disposal site was revoked by the Department of
Natural Resources on November 10,1982, and PAB Oil was
ordered to proceed with a closure plan for the site. By 1983,
the company reportedly lacked the funds for a proper closure.
It is now out of business, and the wastes are still on site. The
site was placed on the National Priority List (NPL) on March
31, 1989, because of its potential to contaminate the Chicot
Aquifer, which is a major source of drinking water in the area
(U.S. EPA, 1991).
The material contained in the PAB Oil site pits and
surrounding levees is an oily drilling mud which meets DTC's
description of a preferred waste type for the SITE demon-
stration. DTC's SITE proposal indicated the technology
could apply to oil-soluble organic contaminants as well as
petroleum sludges and petroleum-based oil contaminated soils.
In May 1991, about 1,000 kilograms of this material were
collected, loaded into drums, and shipped to EPA's Edison,
NJ research facility for treatment during the demonstration.
C.2 Description of Operations
Drilling mud waste was stored in drums within a bermed
storage area in Building 245 at the EPA facility. Prior to
initial system startup, EPA and the SITE team contractor
reviewed the Demonstration Plan for the Carver-Greenfield
Process (PRC, 1991) with DTC personnel. During startup, the
system was checked for problems that would prevent smooth
operation of the equipment
Pilot plant shakedown started the third week of July and
continued into early August. Silt and later bentonite were
used for the shakedown. Isopar-L was used as the extraction
solvent Several problems were encountered and solved dur-
ing the shakedown. A gummy material formed when the silt
was wetted, plugging some process lines. The upper jacket of
the desolventizer leaked, discharging heavy heating oil from
the jacket into the solids in the unit. This temporarily inter-
rupted the pilot plant shakedown. The whole system was
cleaned and flushed with Isopar-L to remove residues.
In the next shakedown attempt, DTC used a surfactant
with the silt to avoid forming the gummy substance during
start-up. The shakedown went smoothly, and a dry final
product resulted. Laboratory analysis of the final product,
using SOW procedures, showed the presence of about 4%
indigenous oil. Clean silt was then analyzed by the SOW
procedure and was found to be free of indigenous oil. This led
to the conclusion that the surfactant was detected as indigenous
oil in the SOW procedure. It was decided, based on this
conclusion, that surfactant would not be used in either the
blank run or waste runs since it could to contribute oil
contamination to the product solids.
After shakedown was complete, DTC attempted to com-
plete the blank run on July 29,1991. A silt fraction was used
as feed solids instead of sand, as earlier stated in the Demon-
stration Plan. No surfactant or add-back was used while
charging silt to the fluidization tank. Most of the operational
changes made for the blank run were implemented by DTC to
overcome the difficulties encountered during shakedown.
The blank run was attempted again on August 1, 1991.
Operational modifications for this run were preapproved by
EPA. Bentonite was used as the solid matrix instead of sand
or silt due to its higher water holding capacity and its closer
similarity to PAB Oil waste solids. DTC did not use surfac-
tant or add-back while charging the feed in the fluidization
tank. The initial blank run also ran into several operational
29
-------
problems and was canceled. The line between the centrifuge
feed tank and (the centrifuge became plugged with gummy
material. Despite repeated efforts to clear the blockage, the
gummy slurry could not be pumped to the centrifuge. The
scrubber was also blocked, due to the sticky nature of the
slurry.
Although these attempts to start the blank run failed, each
attempt provided information which helped optimize opera-
tions. In retrospect, the shakedown runs should have used the
same feedstock as the blank run. This would have likely
prevented the false starts for the blank run.
The SITE demonstration started on August 4,1991. The
initial run was a blank run. Prior to the blank run, no waste
feed was admitted to the system. Bentonite was used as the
solid matrix since it simulated the waste solids. Blank run
samples were collected in accordance with the Demonstration
Plan.
Waste feed processing began after the blank run. Two
waste feed test runs (Runs 1 and 2) consisting of three
extraction steps each were conducted during this phase of the
demonstration over two consecutive weeks. During the waste
feed runs, samples were collected at various process points.
These samples included waste feed, raw solvent, slurried
feedstock, centrate, centrifuge cake, condensed water, con-
densed solvent, solids product and vent gas. The number of
samples collected at each location, the frequency, and the
rationale for sampling and analysis parameters are discussed
in Section 3 of the Demonstration Plan (PRC, 1991), as well
as in the Technology Evaluation Report (U.S. EPA, 1992).
The following briefly discusses each sampling location:
Location 1—Waste Feed: The waste feed was sampled
from the cement mixer just before transfer to the fluidization
tank. These samples were analyzed for SOW, solvent, TPH,
VOC, SVOC, metals, and ignitability.
Location ^-Solvent: The fresh solvent (Isopar-L) was
sampled, prior to the blank run, from a randomly selected
drum. It was analyzed for solvent, VOC, SVOC, and metals.
Location 3—Slurried Feedstock: The fluidized feedstock/
solvent mixture was sampled from the fluidization tank recir-
culation pump. Samples were taken for each extraction phase.
All samples were analyzed for solvent, SOW, and TPH to
confirm the ratio of solvent to solids.
Location 4—Centrate: The centrates from each extrac-
tion were sampled from the centrate tank. Samples were
analyzed for SOW, solvent, VOC, SVOC, and TPH.
Location 5—Centrifuge Cake: Grab samples of the cen-
trifuge cake were taken in each extraction. The samples were
analyzed for solvent and SOW.
Locations 6 and 7—Condensed Water/Solvent: During the
first extraction, the water was evaporated and condensed.
Solvent vapors at this point were also condensed and subse-
quently collected with condensed water in a single drum. The
vapor losses from second and third extractions were also
collected in the drum. The water phase was manually sepa-
rated from the oil phase using a separatory funnel. Condensed
water samples were analyzed for solvent, TPH, VOC, SVOC,
metals, and conventional pollutants. Condensed solvent
samples were analyzed for solvent, TPH, and metals.
Location 8—Solids Product: The final solids product
was collected in a stainless steel drum. The drum contents
were mixed before samples were taken. Samples were analyzed
for SOW, solvent, TPH, VOC, SVOC, metals, ignitability,
and TCLP.
Location 9^-Vent Gas: All gases that were not con-
densed were passed through a granular activated carbon can-
ister that had a measured quantity of carbon. At the end of the
full batch run, the canister was opened and samples of activated
carbon were taken using a sample thief. Each carbon sample
was analyzed for solvent
C.3 Analytical Results and Discussion
This section discusses the analytical results of the C-G
SITE demonstration. First, the feedstock characterization
results are discussed. Second, the complete analytical dem-
onstration is presented, including VOC, SVOC, metals, and
TPH. Third, indigenous oil removal efficiency is discussed.
The next topic discussed is the TCLP results for the final
product Finally, the mass balance of materials during the
treatment process is discussed. The Carver-Greenfield Process
Technology Evaluation Report (U.S. EPA, 1992) provides a
complete presentation of the analytical results.
C.3.1 Feed Characterization
The analyses used to characterize the waste feed included
SOW, TPH, solvent, VOC, SVOC and metals. The compo-
sition of raw waste feed used in the first and second test run is
shown in Table C-l.
The two waste feeds were similar in solids content but
differed in indigenous oil and water content. The waste feed
in the first test run was lower in water content but had a higher
indigenous oil content than the second test run waste feed.
The feedstock analyses for Runs 1 and 2 are presented in
Tables C-2 and C-3.
In feedstock for Test Run 1 (Table C-2), only xylene was
found at detectable levels. Other volatile compounds (toluene
and ethylbenzene) and semivolatile compounds (phenanthrene
and 2-methyl naphthalene) were found at concentrations less
than the method detection limit. In feedstock for Test Run 2
(Table C-3), ethylbenzene and xylene were found at detect-
able levels while again other volatiles (benzene and toluene)
and semivolatiles (phenanthrene, 2-methyl naphthalene, and
Table C-1. Composition of Waste Feeds
Test Run Solids (%) Indigenous Oil % Water (%)
1
2
52.35
52.44
17.47
7.26
21.75
34.7
30
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Table C-2. Carver-Greenfield Process- Test Run 1
Parameters
Units
S1
S2
S3
Feedstock
54
S5
SVOC - acid extractables
. none (V-9/kg)
(wetwt)
SVOC - base neutral extractables
phenanthrene
All analyses below detectable limits
(wet wt)
2-methyl naphthalene (wetwt)
Metals
aluminum
barium
beryllium
boron
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
nickel
potassium
sodium
strontium
vanadium
SOW
solids
indigenous oil
water
Solvent
Isopar-L
TPH
total
Ignitability (°C)
NA - Not analyzed
16700
100000U
(V9/9)
(wet wt)
52.67
17.06
24.21
155000
>100
16300
10900
52.03
17.07
22.61
137000
>100
14000
10200
13700
10200
51.90
16.96
20.96
138000
>100
52.70
17.04
21.30
143000
NA
19200
14300
52.87
18.23
20.75
165000
NA
S6
voc
toluene (l*-9/kg)
ethylbenzene (wet wt)
total xylene (o,m,p)
585
883
3480
470
965
3710
-
620
1090
3870
545
1100
3730
573
935
3500
480
983
3660
15800
11500
11400
3590
0.80
47.9
0.709
2180
25.6
7.42
16.1
13100
39.8
1510
365
13.9
426
140
67.8
24.0
159
10800
3170
1.08
20 U
0.592
2060
25.2
7.07
16.2
14500
41.8
1520
351
13.3
370
147
62.5
29.1
154
11700
3140
0.833
20 U
0.576
2110
26.1
8.11
15.8
13200
38.6
1560
373
13.7
532
126
67.6
25.9
156
10500
1600
0.779
20 U
0.481
2140
25.7
7.02
17.2
14000
41.9
1540
347
13.1
496
128
63.0
23.4
168
10800
3310
0.76
20 U
0.567
2170
25.9
6.98
16.5
13100
38.1
1610
350
' 13.1
586
140
64.6
23.3
163
8780
3130
0.731
20 U
0.545
2150
24.0
8.01
16.5
13500
45.7
1360
450
12.4
497
126
61.7
19.9
162
51.91
18.52
20.67
143000
NA
naphthalene) were found at levels less than the detection limit.
The major metals in both feedstocks were aluminum, barium,
calcium, iron, and magnesium. TPH levels ranged from
80,000 to 150,000 jig/l, confirming the high oil values of the
SOW analysis. The feedstock had no detectable Isopar-L
solvent and had an ignitability temperature greater than 100
C.32 Summary of the Major Analytical
Parameters
The demonstration's primary purpose was to show how
well the C-G Process removed indigenous oil from the waste
material. This was assessed by characterizing indigenous oil
content using the SOW, TPH and Isopar-L solvent proce-
dures. Tables C-2 and C-3 summarize analytical results for
the two test runs.
C.3.3 Characterization of Oil Removal
Efficiency
The efficiency of the C-G Process for the PAB Oil SITE
demonstration was based strictly on its ability to remove
indigenous oil. Indigenous oil removal is based on the results
of the SOW, TPH, and solvent analytical procedures. The
indigenous oil result determined in the SOW procedure in-
31
-------
Table C-3. Carver-Greenfield Process- Test Run 2
Parameters Units ST
Feedstock
S2
S3
54
S5
S6
voc
bonzene
toluene
ethylbenzene
total xytene (o,m,p)
fag/kg)
(wet wt)
1250 U
763
1860
8820
688
803
1960
9000
1250 U
1150
2060
9270
1250 U
1130
1510
7870
1250 U
1210
2140
10000
766
1220
1790
8280
SVOC - add extractables
none
All analyses below detectable limits
(wet wt)
SVOC - base neutral extractables
phenanthrene
2-methyl naphthalene (wet wt)
naphthalene
11000
45500
50000U
11500
50900
17600
12100
55800
17500
1090
36600
50000U
1070
48800
16200
12000
57300
19200
Metals
aluminum
barium
beryllium
boron
cadmium
calcium
chromium
cobalt
copper
iron
lead
magnesium
manganese
molybdenum
nickel
potassium
sodium
strontium
vanadium
zinc
SOW
solids
Indigenous oil
water
Solvent
Isopar-L
TPH
total
Ignitabitlty (°C)
frg/g) 7380
(wet wt) 653
0.65
31.6
3.90
8000
140
9.15
83.8
20000
207
1260
266
23.8
20.6
711
609
261
21.5
1000
(%) 52.31
7.37
36.62
(%) <0.1
frg/g) 79200
>100
7150
688
0.63
20 U
4.10
7630
138
8.89
87.2
19300
196
1190
264
24.8
19.7
726
579
236
20.8
1030
53.00
7.78
34.95
<0.1
78600
>100
7100
666
0.73
20 U
4.07
7570
137
10.0
87.8
19700
208
1230
284
26.4
19.7
707
597
279
22.6
990
52.69
7.05
34.07
100
7230
450
0.79
20 U
4.01
7980
140
9.54
93.7
25500
205
1300
285
26.8
20.7
778
622
286
22.2
1030
52.06
6.51
34.74
<0.1
82500
NA
7610
520
0.74
20 U
3.82
7840
141
9.33
92.2
19800
213
1260
276
25.6
21.9
785
607
298
22.4
1020
52.08 x
7.69
33.63
<0.1
103000
NA
7640
478
0.68
20 U
4.12
7690
141
9.52
86.3
20100
202
1270
281
24.7
22.4
76
581
264
22.7
1010
52.50
7.03
34.61
0.10
98100
NA
NA - Not analyzed
Table C-4. Oil Parameters for Feedstock and Final Product
SOW
Isopar-L
Calculated Oil
Solids
Oil
Water
TPH
As Solvent As TPH
Indigenous Indigenous Non-TPH
Oil TPH Oil
Test Run 1
Feedstock
Final Product
Test Run 2
Feedstock
Final Product
52.35
96.56
52.44
98.31
17.48
1.38
7.24
0.85
21.75
0
34.7
0
14.7
0.79
8.9
0.66
0
0.93
0
0.99
0
0.84
0
0.89
17.47
1.38
7.24
0.85
14.7
0
8.9
0
2.77
1.38
0.85
32
-------
Table C-5. Oil Removal Efficiency Percent Removal
Test Run 1
Test Run 2
True
Indigenous Oil
92.1 ,
88.3
Indigenous
TPH
100
100
Table C-6. Toxiclty Characteristic Regulatory Limits and TCLP Results from Test Run 1 Treated Solids
Parameters
Regulatory
Limits
(mg/l)
Average
Biased
(mgfl)
Average
Unbiased
(mg/l)
Average
Recovery
VOC
benzene 0.5
carbon tetrachloride '~" 0.5
chlorobenzene 100.0
chloroform 6.0
1,2-dichloroethane 0.5
1,1-dichloroethene 0.7
methyl ethyl ketone 200.0
tetrachloroethene. 0.7
trichloroethene 0.5
vinyl chloride 0.2
SVOC - add extractables
m+p-cresol 100.0
o-cresol (combined)
pentachlorophenol 100.0
2,4,5-trichlorophenol 400.0
2,4,6-trichlorophenol 2.0
SVOC - base neutral extractables
1,4-dichlorobenzene ~ 7.5
2,4-dinitrotoluene 0.13
hexachlorobenzene 0.13
hexachloroethane 3.0
nitrobenzene 2.0
pyridine 5.0
hexachloro-1,3-butadiene 0.5
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.05 U
0.10 U
0.10 U
0.20 U.
0.10 U
0.1 OU
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.05 U
0.10 U
0.10 U
0.20 U
0.10 U
0.10 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
97.00
96.33
98.67
97.00
98.67
97.00
75.33
95.00
94.00
99.00
35.00
40.33
64.67
53.67
58.67
44.00
55.00
55.00
42.33
57.00
30.67
42.33
Metals
arsenic
barium
cadmium
chromium
lead
mercury
selenium
silver
5.0
100.0
1.0
5.0
5.0
0.2
1-0
5.0
0.50 U
1.18
0.10 U
0.10 U
0.10 U
0.002 U
0.50 U
<0.152
0.50 U
1.17
0.10 U
0.10 U
0.10 U
0.002 U
0.50 U
<0.130
108.33
100.33
108.67
105.67
105.00
68.33
100.33
81.00
U - indicates compound was analyzed for but was not observed at quantifiable concentrations •
Biased values incorporate compound-specific matrix interferences detected by spike analysis for each regulated
compound
eludes a broad range of organics soluble in toluene. Petro-
leum hydrocarbons, as well as other polar and nonpolar organics
are detected in the SOW procedure. The TPH procedure
detects only nonpolar organics, which includes the Isopar-L
solvent. The solvent procedure uses gas chromatography and
detects only the Isopar-L solvent This overlapping nature of
the SOW, TPH, and solvent procedures makes it difficult to
determine true indigenous oil removal directly.
The indigenous oil fraction of the SOW procedure for the
feed stock and final products represents those oils that origi-
nate solely from the waste material. Because TPH, which is a
widely used parameter for regulating land application of
sludges, soil contamination and fill suitability, detects the
Isopar-L solvent, the only way to estimate indigenous TPH in
the product solids is to subtract the Isopar-L solvent result
from the TPH result.
33
-------
Table C-7. Toxlclty Characteristic Regulatory Limits and TCLP Results from Test Run 2 Treated Solids
Parameters
Regulatory
Limits
(mg/l)
Biased
(mg/l)
Average
Unbiased
(mg/l)
Average
Recovery
VOC
benzene 0.5
carbon tetrachloride 0.5
chlorobenzene 100.0
chloroform 6.0
1,2-dichloroethane 0.5
1,1-dichloroethene 0.7
methylethyl ketone 200.0
tetrachhroethene 0.7
trichtoroethene 0.5
vinyl chloride 0.2
SVOC - acid extractables
m+p-cresol 100.0
o-cresol (combined)
pentachlorophenol 100.0
2,4,5-trichlorophenot 400.0
2,4,6-trichlorophenol 2.0
SVOC - base neutral extractables
1,4-dichlorobenzenB 7.5
2,4-dinitrotoluene 0.13
hexachtorobanzene 0.13
hexachloroethane 3.0
nitrobenzene 2.0
pyridina 5.0
hexachtoro-1,3-butadiene 0.5
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.20 U
0.10 U
0.10 U
0.20 U
0.10 U
0.10 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
0.05 U
0.20 U
0.10 U
0.10 U
0.20 U
0.10 U
0.1 OU
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.10 U
0.05 U
94.67
93.00
94.67
96.33
96.33
100.67
87.33
95.00
93.67
98.67
37.00
44.00
91.00
61.00
67.00
47.00
55.00
59.00
45.00
54.00
27.00
46.00
Metals
arsenic
barium
cadmium
chromium
lead
mercury
selenium
silver
5.0
100.0
1.0
5.0
5.0
0.2
1.0
5.0
0.5 U
• 3.44
0.10 U
0.10 U
0.10 U
0.002 U
0.50 U
0.10 U
0.5 U
2.91
0.10 U
0.10 U
0.10 U
0.002 U
0.50 U
0.10 U
91.67
85.00
84.33
84.00
86.33
55.67
82.67
61.33
U - indicates compound was analyzed for but was not observed at quantifiable concentrations
Biased values incorporate compound-specific matrix interferences detected by spike analysis for each regulated compound
Table C-4 summarizes the relevant oil parameters for
feedstock and final product samples from both test runs. The
calculated oil values denoted as "true indigenous oil" and
"indigenous TPH" are derived as previously discussed. The
difference between these two values is oil not detected by the
TPH procedure. Non-TPH indigenous oil ranged from 0.85%
in Test Run 2 to 1.28% in Test Run 1. Table C-5 shows oil
removal efficiency for both test runs based on the results in
Table C-4.
This approach qualitatively characterizes oil removal.
This is because quantifying oil removal is difficult due to the
overlapping nature of the analyses. Final product TPH or oil
by the SOW procedure can be directly determined if this is the
objective. If, however, the objective is to remove the oil
indigenous to the waste, understanding of the analytical meth-
ods and calculation involving the results of these methods is
necessary. Tables C-4 and C-5 reflect this method of oil
removal characterization.
While the final product TPH ranged from 0.66% to
0.79% in both test runs, no indigenous TPH was detected in
both final products. Final product indigenous oil by the SOW
procedure ranged from 0.85% to 1.38%. Using the calculated
true indigenous oil and indigenous TPH values, indigenous ,oil
removal ranges from 88% to 100%.
C.3.4 TCLP Results
The raw pit waste sample from PAR Oil Site was col-
lected in November 1990 to characterize the waste for the
demonstration and was analyzed by TCLP. The waste sample
passed TCLP, and therefore was not a RCRA-characteristic
waste.
TCLP tests were performed on the treated solids product
of Test Runs 1 and 2. Tables C-6 and C-7 present the results L
for Test Runs 1 and 2, respectively. These tables also include
the appropriate RCRA regulatory criteria. The results indi-
34
cate that the treated solids product in test runs 1 and 2 was not
a RCRA-characteristic waste.
C.3.5 Mass Balance
A mass balance was performed on the C-G Process using
materials inventory data (total waste feed, solids, water and
indigenous oil phases) for each test run. Mass balancing
accounts for components of the waste feed and other process
inputs as compared to products and residuals. Mass balance
closure determines the amount of each constituent in the
waste feed and other inputs which can be accounted for in the
products and waste streams of the process. A gross mass
balance accounts for only the major components such as
solids, soil and water. Detailed mass balances account for
other components, such as organics and metals.
A gross i mass balance performed on the C-G Process
showed about 96.2% combined recovery of all the constituents
for Test Run 1, and a 96.4% recovery for Test Run 2. On a
constituent basis, 81.2% solids, 112.2% water and 97.3% oil
phases were recovered in Test Run 1. Similarly, 78.9%
solids, 95.8% water and 98.3% oil phases were recovered in
Test Run 2. A detailed mass balance of the C-G Process is
discussed in the Carver-Greenfield Process Technology
Evaluation Report (U.S. EPA, 1992).
References
PRC, 1991. Demonstration Plan for the Carver-Greenfield
SITE Demonstration Program Report (June).
U.S. Environmental Protection Agency (U.S. EPA), 1991.
Data Summary Report, PAB Oil and Chemical Services Su-
perfund Site, Vermilion Parish, Louisiana.
U.S. EPA, 1992. Technology Evaluation Report. SITE
Program Demonstration of the Dehydro-Tech Corporation's
Carver-Greenfield Process, EPA/540/XX-92/XXXX (to be
published).
35
-------
Appendix D
Carver-Greenfield Process Case Studies
Note: This appendix to EPA's Applications Analysis
Report was prepared by Dehydro-Tech Corporation (DTC).
Claims and interpretations of results in this Appendix are
those made by the vendor and are not necessarily substantiated
by test or cost data. Many of DTC's claims regarding cost and
performance can be compared to the available data in Section
4 and Appendix C of the Applications Analysis Report.
This appendix summarizes case studies on the Carver-
Greenfield Process. The following case studies are covered:
Case Study
Description
D-l Refinery Slop Oil from Northeast U.S.
D-2 Petroleum Sludge from East Coast Refinery
D-3 Wool Scouring Waste at Burlington Industries
Case Study D-l
Material Processed: Refinery Slop Oil
An oil refinery "slop oil" containing 12 weight percent
solids and 72 weight percent water from a wastewater pond in
the Northeast was processed by DTC for treatability evaluation
and plant design guidance. This material was separated into
its solid, water, and indigenous oil fractions in DTC's stationary
pilot plant. The equipment used in the stationary pilot plant is
similar in design and operation to that of the mobile pilot plant
used for the SITE demonstration.
A 39.2-lb charge of slop oil sample was slurried with 80
pounds of a narrow boiling paraffinic solvent (boiling point =
370 to 380 °F), to which had been added about 0.4 Ib of a
surfactant to aid suspension, and pumped around in a forced-
circulation evaporation system. Water was evaporated at the
rate of 35 to 45 Ib/hr at 11 in. of Hg vacuum and 180 to 235 °F
until there was less than 1 weight percent water on the solids
product The dried slurry was cooled and centrifuged batchwise
in a Fletcher centrifuge with a perforated bowl at 1200 G
force. The centrifuge cake contained about 48 weight percent
solids, 4.6 weight percent indigenous oil, and 47 weight
percent solvent.
The centrifuge cake was split into two samples. Sample 1
was solvent extracted once. Sample 2 was solvent extracted
twice. These solid samples were deoiled in a vacuum oven at
300 °F and 29 in. of Hg vacuum. After deoiling, the solid
samples contained 2 weight percent and 0.2 weight percent
indigenous oil and less than 0.1 weight percent solvent, as
shown in Table D-l.
The pH of the feed slop oil was 7.3 and that of the water
condensate 6.0.
The forced circulation evaporation system was charged
with 104 pounds of a solvent/indigenous oil mixture and the
solvent was evaporated at about 250 "F and 26 in. Hg vacuum.
Steam was added to assist stripping at the end of the run which
produced an indigenous oil product with less than 0.8 weight
percent solvent
According to the refiner, the original slop oil was unsuit-
able for landfilling due to the presence of a variety of com-
pounds. The Rocky Mountain Laboratory in Boulder, CO
tested the dry solids after treatment in the C-G Process and
determined that both samples met all the prevailing require-
ments for non-hazardous landfilling as specified by the EPA.
Sufficient process and design data was developed from
the above testing to design a commercial unit to process this
slop oil.
Table D-1. Sample Composition
Slop Oil
Component (weight %)
Solids 12.0
Indigenous 16.0
Hydrocarbons
Water 72.0
Solvent 0.0
Total 100.0
Fresh Slurry
(weight %)
3.9
5.3
23.7
67.1
100.0
Solids (weight %)
Sample 1
97.8
2.0
-------
circulation the feed was heated and the solids dried by evapo-
rating the water present Two stages of evaporation were
simulated. The feed compositions and operating conditions
for drying are. listed in Table D-2.
During the water evaporation approximately 12 weight
percent of the indigenous oil in the feed was vaporized and
condensed with the water.
The dry slurry was centrifuged while hot in a Fletcher
basket centrifuge using a solid bowl at 1200 G force. The
collected solids were reslurried in a narrow boiling solvent
(BP=370 to 380 °F) and filtered using a Buchner funnel. The
filter cake solids were deoiled in a vacuum oven at about 250
°F and 28 in. of Hg vacuum.
The deoiled product solids properties are listed in Table
D-3.
Although the solids recovered were very fine, all the feed
mixtures were processed without difficulty. This case showed
that starting with feed materials having a high indigenous oil
to solids ratio (in the range of 25 to 40), the C-G Process was
able to produce solids containing only 3.8% to 5.4% indigenous
oil. Lower levels could be achieved, if required, by further
extractions with a suitable solvent. The refinery advised DTC
that the hazardous compounds present in the original feed
materials, such as benzene and phenol, had been effectively
extracted from the solids.
Sufficient process and design data was developed from
the above testing to design a commercial plant
Case Study D-3
Material Processed: Wool Scouring Waste
Table D-2. Feed Compositions
Feed Materials Feed Mix A
Feed Mix B Feed Mix C
DAF Sludge 26.5% 26.5% 26.5%
API Separator Bottoms, — — 2.9
Tank Bottoms — 12.3 —
Bio Sludge 10.2 10.2 11.3
Emulsions 63.3 51.0 56.4
Total 100.0% 100.0% 100.0%
Feed Components
Solids 1.5% 1.6% 2.1%
Water 44.0 35.2 44.7
Indigenous Oil 57.6 63.8 53.2
Total 103.1% 99.6% 100.0%
Operating Conditions
First Stage-
TemperaturB,°F 150 152 152
Vacuum, inches Hg 23.0 23.0 23.1
H2O Evaporated, Ib/hr 33.8 27.8 30.2
CondensatepH 9.0 8-9 8-9
Second Stage-
Temperature, °F 197 198 201
Vacuum, inches Hg 12.0 11.0 11.8
H2O Evaporated, Ib/hr 30.0 30.2 32.0
CondensatB pH' 5.0 5-6 5-6
A number of samples of wool scouring waste and indus-
trial activated sludge from the Burlington Industries,
Clarksville, VA plant was furnished to DTC for treatability
testing in DTC's stationary pilot plant The processing objec-
tives were twofold: to treat the waste streams suitably for
discharge to the environment and to extract lanolin as a valued
by-product from the oil in the wool scouring waste.
The ranges of composition of each feed which were
processed separately and in mixtures in the pilot plant were:
The ratio of wool scouring waste to activated sludge to be
processed together was about 18 to 1.
Numerous pilot plant runs were made to determine the
optimum processing scheme for these materials on a com-
mercial scale. Formulation of the design basis for the scale-up
included determining:
a) the required number of evaporation stages for effi-
ciently removing the high quantity of water present in the
wool scouring waste,
b) the optimum stage for adding a hydrocarbon solvent
to minimize solids deposition and to permit the water evapo-
ration to be completed,
c) the appropriate stage to add the activated sludge to
the wool scouring waste being processed, and
d) the optimum processing conditions for recovery of
lanolin.
Based on the results of the pilot plant work, a commercial
plant was designed and installed at the Burlington Industries
facility in Clarksville, VA for the following combination of
feeds:
The commercial plant, started up in 1985, includes an
energy efficient five-stage multi-effect evaporation system,
centrifuge, a three-stage solids deoiling system, an acidifica-
tion system, evaporation facilities for solvent recycle, and a
solvent stripping unit for product lanolin recovery. The
recovered product water is discharged to a waste treatment
facility and the solids are incinerated.
The original design anticipated fluidizing the wool scour-
ing waste in a narrow-cut paraffinic solvent and feeding it to
the first four evaporator effects operating at 120, 140, 160,
and 180 °F, respectively. The fourth stage product would be
acidified and mixed with the remaining solvent and the acti-
vated sludge and fed to the fifth stage which operated at 260
Table D-3. Deoiled Product Solids Properties
Feed Mix A Feed Mix B Feed Mix C
Solids
Water
Indigenous Oil
Solvent
Total
95.5%
<0.1
4.3
<0.1
100.0%
96.0%
<0.1
3.8
<0.1
100.0%
94.4%
<0.1
5.4
<0.1
100.0
38
-------
Table D-4. Wool Scouring Waste Composition
Activated Sludge Wool Scouring Waste
Water, wt%
Solids, wt%
Oil,wt%
pH
83.5-85.1
12.7-15.8
1.8-2.2
6.0-6.5
94.4-98.8
0.7-3.4
0.6-2.2
6.1-8.1
Table D-5. Commercial Plant Feed Composition
Activated Sludge
Composition Flow Rate
(wt%) (Ib/hr)
Wool Scouring Waste
Composition Flow Rate
(wt%) (Ib/hr)
Water
Solids
Oil
Total
85.0
12.8
2.2
100.0
1,880
283
50
2,213
94.4
3.4
2.2
100.0
37,600
1,342
880
39,822
Subsequent to start-up, the expected feed analysis of the
wool scouring waste became less than 1.5 weight percent
solids and less than 1 weight percent oil (versus design values
of 3.4 and 2.2 weight percent, respectively). Equipment
modifications were made to accommodate this change and
presently the evaporation of water from the wool scouring
waste takes place without solvent present in the first three
stages of the evaporator. Solvent is added to the fourth and
fifth stages and activated sludge is added to the fifth stage.
During typical operations product solids contain an average of
0.6 weight percent water and 0.9 weight percent solvent.
Solvent is not detected in the effluent water condensate.
Steam consumption is about 0.3 Ib of steam per Ib of water
evaporated.
The unit has been operating reliably since 1985.
-------
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
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EPA
PERMIT No. G-35
EPA/540/AR-92/002
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