xvEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/540/AR-92/014
August 1993
Membrane Treatment of
Wood Preserving
Site Groundwater by
SBP Technologies, Inc.
Applications Analysis Report
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
-------
EPA/540/AR-92/014
August 1993
Membrane Treatment of Wood Preserving
Site Groundwater by SBP Technologies, Inc.
Applications Analysis Report
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
"1^ Printed on Recycled Paper
-------
Notice
The information in this document has been funded by the U.S. Environmental Protection Agency under the auspices of the
Superfund Innovative Technology Evaluation (SITE) Program under Contract No. 68-CO-0048 to Science Applications
International Corporation. It has been subjected to the Agency's peer and administrative review, and it has been approved
for publication as an EPA document. Mention of trade names or commercial products does not constitute an endorsement or
recommendation for use.
-------
Foreword
The Superfund Innovative Technology Evaluation (SITE) Program was authorized in the 1986 Superfund Amendments. The
Program is a joint effort between EPA's Office of Research and Development and Office of Solid Waste and Emergency
Response. The purpose of the program is to assist the development of hazardous waste treatment technologies necessary to
implement new cleanup standards which require greater reliance on permanent remedies. This is accomplished through
technology demonstrations designed to provide engineering and cost data on selected technologies.
This project was designed to evaluate the effectiveness of SBP's formed-in-place membrane process on wood preserving
waste contaminated groundwater and establish the potential applicability at other Superfund or hazardous waste sites. This
process separates contaminated water into a large volume of relatively uncontaminated permeate potentially suitable for
discharge and a smaller volume of a contaminant-rich concentrate suitable for biodegradation or other means of final
destruction. The study was carried out at the American Creosote Works facility in Pensacola. Florida, a site where wood
preserving operations had been carried from 1902 to 1981 using creosote and. more recently, pentachlorophenol. The study
is summarized in this Applications Analysis Report and described in more detail in the companion Technology Evaluation
Report.
Additional copies of this report may be obtained at no charge from EPA's Center for Environmental Research Information,
26 West Martin Luther King Drive, Cincinnati, Ohio 45268. using the EPA document number found on the report's front
cover. Once this supply is exhausted, copies can be purchased from the National Technical Information Service, Ravensworth
Bldg., Springfield, VA, 22161, 703-487-4600. Reference copies will be available at EPA libraries in their Hazardous Waste
Collection.
E. Timothy Oppelt. Director
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
111
-------
Abstract
This document provides an evaluation of the SBP Technologies, Inc. (SBP) formed-in-place membrane hyperfiltration process.
The purpose of the technology is to reduce the volume of waste requiring further treatment through such techniques as
immobilization or destruction. This volume reduction technology, when coupled with other technologies, may reduce total
treatment costs and minimize off-site transportation of hazardous materials. Using cross-flow filtration to minimize fouling,
the membrane filtration system separates contaminated groundwater and other waste waters into a small, concentrated stream
that can be treated biologically or otherwise, and a relatively clean permeate that can be discharged, reinjected. or reused with
little or no additional treatment. In hyperfiltration, pollutants are separated on the basis of molecular weight, molecular size,
polarity, or charge.
This report summarizes the utility and application of SBP's membrane system to the treatment of organic contaminated
wastewater. This analysis utilizes information from the Superfund Innovative Technology Evaluation (SITE) Program's
demonstration at the American Creosote Works wood preserving site in Pensacola, Florida as well as data from other SBP
investigations. Conclusions were reached concerning the technological effectiveness and economics of the process and its
suitability for use at other sites and with other waste waters.
During the SITE demonstration, operations were carefully monitored to establish a database against which the vendor's claims
for the technology could be evaluated. These claims were that the filtration system would (1) provide an 80% volume
reduction for the contaminants in the feed stream; and (2) achieve 90% removal of semivolatile contaminants, based on a
comparison of the concentrations in the feed stream and those in the permeate from the filtration system.
Based on the demonstration study using the system as configured and as used, an 83% reduction in the volume of the
contaminated feed water was achieved. However, the system achieved a 74% overall removal of the designated semivolatile
components, which included low molecular weight phenols and polynuclear aromatic hydrocarbons (PAHs). The filtration
system was much more effective at removing the PAHs than phenols. The average removal efficiencies were 92% for PAHs
and 18% for phenols.
Capital and operating costs for the system are estimated to be between $220 and $1,740 per thousand gallons (on an annual
basis), dependent on the type and magnitude of contamination encountered in the waste stream.
-------
Contents
Section Page
Notice ii
Foreword iii
Abstract iv
Figures vii
Tables viii
Abbreviations and Symbols ix
Conversion Factors xii
Acknowledgements xiii
Executive Summary 1
1.1 Inlroduction 1
1.2 Conclusions 1
1.3 Discussion of Conclusions 2
2. Introduction 5
2.1 The Site Program 6
2.2 Site Program Reports 6
2.3 Purpose of the Applications Analysis Report 6
2.4 Process Description 6
2.5 Key Contacts 7
3. Technology Applications Analysis 8
3.1 Introduction 8
3.2 Mechanisms of Membrane Separations 8
3.3 Applications of Membrane Processes for the Treatment of Hazardous Waste 9
3.4 Features of SBP's Hyperfiltration System H
3.5 Demonstration Results 11
3.6 Discussion of Demonstration Results and Applications 12
3.7 Applicable Wastes 16
3.8 Site Characteristics 16
3.9 Environmental Regulations Requirements 16
3.10 Materials Handling Requirements 17
3.11 Personnel Issues 19
3.12 Potential Community Exposures 19
-------
4. Economic Analysis 20
4.1 Introduction 20
4.2 Conclusions of Economic Analysis 20
4.3 Issues and Assumptions 21
4.4 Basis for Economic Analysis 21
4.5 Results 26
4.6 Remediation of a Hypothetical Site 26
Appendix A. Process Description 29
A.I Introduction 29
A.2 Process Description 29
Appendix B. Vendor's Claims 31
B.I Introduction - Hyperfiltration System 32
B.2 Results BTEX/Petroleum Hydrocarbons Hyperfiltration 32
B.3 Conclusions - Hyperfiltration System 32
B.4 Introduction - Bioremediation System 32
B.5 PAH and PCP Contamination and Bioremediation 32
B.6 Bioremediation Results 34
B.7 Technology Applications 34
Appendix C. SITE Demonstration Results 36
C.I Introduction.. 36
C.2 Field Activities 37
C.3 Test Procedures 37
C.4 Results 38
VI
-------
Figures
Page
Figure 1. Cross-Flow Filtration 30
Figure 2. Schematic of SBP Filtration System 30
Figure 3. Simplified Process Flow for SBP Technologies Inc.'s Bioreactor System 34
Figure 4. American Creosote Works Site 36
Figure 5. Feed Pressure vs. Run Time 38
Figure6. Flux vs. Run Time 38
Figure 7. Molecular Weight vs. Order of Magnitude Reduction (ORD) 39
vn
-------
Tables
Page
Table 1. Feed and Permeate Semivolatiles - Total Concentrations and Contaminant Reductions 13
Table 2. Individual Semivolatile Concentrations and Rejections 14
Table 3. Conventional Parameters 14
Table 4. Estimated Costs for SBP Filtration Unit 23
Table 5. SBP Labor Requirements and Rates 24
Table 6. Hypothetical Site Cost Analysis 28
Table 7. Classes and Characteristics of PAHs 33
Table 8. Summary of Bioremediation Results of PAH and PCP Removal 34
Table 9. Average Characteristics of Feed Stream to SBP Unit 37
Table 10. Overall Semivolatile Rejection Efficiency for SBP Filtration Unit 39
Table 11. Mass Contribution of Semivolatiles in all Streams 39
Table 12. Behavior on Extended Filtration 40
Table 13. Dioxins/Furans in Process Streams 41
Table 14. Volatiles in Process Streams , 41
vni
-------
Abbreviations and Symbols
BOD biochemical oxygen demand (mg oxygen/liter)
BTEX benzene, toluene, ethyl benzene, and xylenes
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980
COD chemical oxygen demand (mg oxygen/liter)
GCMS gas chromatograph/mass spectrometer
gpd gallons per day
gpm gallons per minute
HSWA Hazardous and Solid Waste Amendments to RCRA - 1984
kwh kilowatt-hour
Mgd million gallons per day
mg/L milligrams per liter
ng/kg nanograms per kilogram
ng/L nanograms per titer
NPL National Priorities List
O&G oil and grease
ORD Office of Research and Development
OSHA Occupational Safety and Health Administration or Act
OSWER Office of Solid Waste and Emergency Response
PAHs polynuclear aromatic hydrocarbons
ix
-------
PCBs polychlorinated biphenyls
PCP pentachiorophenol
PEL Permissible Exposure Limit
POTW publicly owned treatment works
ppb parts per billion
ppm parts per million
ppt parts per trillion
psi pounds per square inch
PVC polyvinyl chloride
QA/QC quality assurance/quality control
RCRA Resource Conservation and Recovery Act of 1976
RI/FS Remedial Investigation/Feasibility Study
RREL Risk Reduction Engineering Laboratory
SAIC Science Applications International Corporation
SARA Super-fund Amendments and Reauthorization Act of 1986
SITE Superfund Innovative Technology Evaluation
SBP SBP Technologies, Inc., formerly Southern Bio Products, Inc.
TDS total dissolved solids (mg solids/liter)
TOC total organic carbon (mg carbon/liter)
TPH total petroleum hydrocarbons
TSS total suspended solids (mg solids/liter)
VOCs volatile organic compounds
-------
Conversion Factors
English (US) x
.Factor
Metric
Area:
Flow Rate:
Ift2
Iin2
1 gal/min
1 gal/min
1 Mgal/d
1 Mgal/d
1 Mgal/d
1ft
lin
lyd
lib
lib
1ft3
1ft3
Igal
-M- ^»-M.
Igal
x
x
X
X
X
X
X
X
X
X
X
X
X
X
X
X
9.2903 x 10-2 =
6.4516
6.3090 xlO'5 =
6.3090 xlO'2 =
43.8126
3.7854xl03
4.3813 xlO'2 =
0.3048
2.54
0.9144
4.5359 xlO2
0.4536
28.3168
2.8317 xlO'2 =
3.7854
3.7854xlO-3 =
m2
cm2
m3/s
L/s
L/s
m3/d
m3/s
m
cm
m
g
kg
L
m3
L
m3
Length:
Mass:
Volume:
ft = foot, ft2 = square foot, ft3 = cubic foot
in = inch, in = square inch
yd = yard
Ib = pound
gal = gallon
gal/min (or gpm) = gallons per minute
Mgal/d (or MGD) = million gallons per day
m = meter, m2 = square meter, m3 = cubic meter
cm = centimeter, on2 = square centimeter
L = liter
o =gram
kg = kilogram
m3& = cubic meters per second
Us = liters/sec
= cubic meters per day
XI
-------
Acknowledgements
This report was directed and coordinated by Ms..Kim Lisa Kreiton, EPA SITE Project Manager in the Risk Reduction
Engineering Laboratory - Cincinnati, Ohio.
This report was prepared for EPA's Superfund Innovative Technology Evaluation (SITE) Program by Dr. Scott W. Beckman,
'Dr. Herbert S. Skovronek, Mr. Omer Kitaplioglu and a cast of thousands at Science Applications International Corporation
for the U.S. Environmental Protection Agency under Contract No. 68-CO-0048. The Work Assignment Manager for this
project was Dr. Scott W. Beckman.
The cooperation and participation of Ms. Heather M. Ford. Dr. David J. Drahos. Dr. Ron Thomas, and supporting staff of
SBP Technologies, Inc. throughout the course of the project and in review of this report are gratefully acknowledged.
Mr. Charles Logan of the Florida Department of Resources (DER) and Ms. Madolyn Streng, the Remedial Project Manager
of USEPA's Region IV, provided invaluable assistance and guidance in initiating the project and in interpreting and
responding to regulatory needs of the project.
Finally, the project could not have been carried out without the efforts of the many SAIC and S-Cubed personnel who were
responsible for the actual sample collection and analyses.
xu
-------
SECTION 1
EXECUTIVE SUMMARY
1.1 Introduction
The SBP Technologies, Inc. membrane filtration system,
using a formed-in-place hyperfiltration membrane, has been
used to treat a creosote and pentachlorophenol (PCP)
contaminated groundwater stream at a Pensacola, Florida site
on the Superfund National Priorities List. Operational and
cost data were collected for that investigation and are the
basis for the evaluation of this process.
SBP's membrane technology can be used as an integral part
of a remediation system to significantly reduce the volume
and toxicity of contaminated wastewater. The technology is
particularly suited for the treatment of contaminated
groundwater as part of a pump and treat system. The
technology reduces risks to human health and the
environment by transferring the contaminants to a smaller
volume facilitating destruction or detoxification by other
technologies. The technology is particularly applicable to
the treatment- of dilute waste streams, where the
concentration of the contaminants into a reduced volume
would result in significant cost savings as well as minimize
off-site treatment. The reduced-volume concentrated residual
could be further treated on-site. or transported off-site for
treatment and disposal.
The system is simple to operate, reliable and requires a
minimum of operator attention or maintenance once the
membrane has been formed. The stability of the system
makes it particularly suitable for long-term use as is
necessary for extended pump and treat remedial programs
The demonstration at the American Creosote Works was
designed to evaluate the two most critical process parameters
for membrane systems; volume reduction and contaminant
reduction. A summary of the demonstration results for these
critical processes parameters are presented below.
1.2 Conclusions
Based on the results of the SITE demonstration project at the
American Creosote Works site in Pensacola, Florida and
information concerning other studies provided by the vendor,
SBP Technologies, Inc., for different wastes at other sites,
several conclusions can be drawn. The conclusions are
organized based on the evaluation factors of volume
reduction and contaminant reduction. In addition, unit
operability and waste applicability are also presented. These
factors are critical in applying the technology to other sites
and wastes.
1. Contaminant Reduction - The SBP filtration unit (as
configured) effectively removed high molecular weight
compounds from the feed stream, but smaller molecular
weight compounds were not removed.
The formed-in-place membrane system is quite effective
(92%) at removing polynuclear aromatic hydrocarbons
(PAHs) found in creosote from the feed water and
producing a permeate with little of these materials.
However, the membrane - as used in the demonstration
- is not very efficient at removing phenolics. Rejections
were in the range of 18% for phenolics. (see Appendix
B for vendor discussion.)
Overall, based on a comparison of total concentrations
of a predesignated list of creosote-derived PAH and
phenolic semivolatile contaminants in the permeate
versus the feed water, the system did not meet the
-------
claimed rejection efficiency of 90%. On the combined
basis, rejection was 74% over the six days of tests.
On the basis of the PAH rejections of over 90%, the
permeate would be expected to be acceptable for
discharge to POTWs with little or no polishing.
Other pollutants found in contaminated waters at wood
treatment facilities (e.g., polychlorinated dioxins and
furans) also are concentrated in the reject stream based
on results of this and other SBP studies. The permeate
retains little of these species.
Other constituents commonly encountered at such sites
including colloidal oils and suspended solids are also
extensively removed by the membrane process. Removal
efficiencies for oil and grease were 93%. Suspended
solids were removed to non-detectable levels. These
materials did not appear to have an adverse effect on
the filtration process.
2. Volume Reduction - The system effectively concentrates
organic contaminants into a concentrate of much smaller
volume.
The volume of wood preserving waste contaminated
waste water was reduced by over 80%. This means that
only 20% of the volume of the feed water would require
further treatment to immobilize or destroy the organic
contaminants.
During an extended run of the system, the volume of
contaminated waste water was reduced by 96.3%. This
represents the maximum volume reduction capability of
the unit for the waste stream tested.
3. Operability -The filtration unit operated consistently and
reliably over the six day testing period. The unit was
easy to operate and maintain.
The filtration unit operated in a batch mode for six
hours each day, for six days, and processed
approximately 1,000 gallons of feed per day. Over the
six day test period, permeate flux was a relatively
constant 0.0085 gallons/min/ft (coefficient of variation
< 10%). Based on a total membrane area of 300 ft2 for
the system, the permeate flow rate for the four module
filtration unit averaged 2.6 gpm.
. Excessive fouling of the membrane, necessitating
frequent cleaning or regeneration, was not encountered.
However, the membrane system did exhibit a gradual
and controllable fouling which required periodic
cleaning.
The operating cost for the membrane process as used at
American Creosote Works is in the range of $220 to
$1,740/1,000 gallons, depending on system size. Major
conaibutors are labor and residuals disposal. Labor costs
decrease significantly as the scale of the process
increases.
Auxiliary equipment that could be needed to support
this process is comparable to that which would be
needed for other above-ground treatment systems such
as oil/water separators and clarifiers for pretreatment,
and filters, carbon adsorbers, etc. for effluent polishing
as required.
4. Waste Applicability
With membranes similar to those manufactured for the
American Creosote Works site, the system could be well
suited for the concentration of polynuclear aromatic
hydrocarbons from wastewaters (groundwater. process
wastes, lagoon leakage, etc.) found at coke plants, wood
preserving sites, and some chemical plants.
Based on the expected mechanisms of membrane
filtration and results from this study, the technology also
may be useful for waste waters containing other large
molecules such as polychlorinated biphenyls (PCBs) and
polychlorinated dioxins and furans, particularly where
these are associated with oil or particulate matter. It
probably is also highly effective for oils, colloidal
solids, and greases.
According, to the developer, the formed-in-place
membrane can be easily modified to conform to waste
characteristics and degree of contaminant removal
desired. Therefore, the membrane can be tailored to the
unique characteristics of the waste stream.
7.3 Discussion of Conclusions
A small scale Filtration Unit with a nominal 5-10 gpm
capacity was tested at the American Creosote Works site
under the Superfund Innovative Technology Evaluation
(SITE) program. Extensive data were collected over six days
(six hours each day) of operation to assess (a) the removal
of wood preserving wastes from contaminated groundwater
at the site; (b) the operational requirements of the system:
and (c) the cost of operation. The data from this study serve
as the primary basis for the foregoing conclusions.
-------
Additional supporting evidence was provided by SBP in the
form of results from other field studies.
A Quality Assurance (QA) program was conducted by SAIC
in conjunction with EPA's QA program, including audits and
data review along with corrective action procedures and
special studies to resolve specific data quality problems. This
program is the basis for the high quality of the data derived
from the SITE project. Discussion of the QA program and
the results of audits, data reviews, and special studies can be
found in the Technology Evaluation Report for this project.
Extensive data were collected on primary pollutants (PCP,
other phenols, and PAHs) and on secondary pollutants (oil,
suspended and dissolved solids, COD, dioxins. and VOC's).
The results of this SITE project demonstrated the ability of
the formed-in-place membrane, operating in a cross-flow
mode, to minimize fouling, and to remove polynuclear
aromatic hydrocarbons from the contaminated feed water. As
operated rejection of the PAHs appears to increase with the
number of aromatic rings, from 78% for naphthalene to
94+% for the 4-ringPAHs. However, similar correlations
appear to exist with molecular weight as well as with the
partition coefftcient reflecting hydrophobicity. The permeate,
accounting for approximately 80% of the feedwater,
contained only about 12% of the predominant PAHs,
naphthalene and phenanthrene.
The removal of phenol and methyl phenols was not
comparably high under the conditions of the demonstration,
with an average rejection of 18%. The concentrations of
phenolics in the permeate could present a regulatory
problem, depending on the concentrations in the feedwater
and the final disposition of the permeate, However, the
vendor states that different membranes and tube
configurations could resolve this issue.
Secondary constituents, such as oil, suspended solids, and
dissolved solids, did not appear to interfere with operation of
the process at the concentrations present in the waste water
studied during the demonstration. Decreases in chemical
oxygen demand (COD), total organic carbon (TOC) and oil
and grease (O&G) indicated that the system removes other
organic species as well as PAHs, but not necessarily with the
same efficiency.
The SBP membrane process would be most applicable to
wastewaters containing large molecular weight organic
compounds (PAHs, dioxins/furans, polychlorinated
oiphenyls. and certain pesticides/herbicides). The system
can remove smaller weight molecular compounds (phenols,
benzene, toluene, ethylbenzene, xylenes) if larger molecular
weight compounds are not abundantly present. Removal of
smaller weight molecular compounds can be accomplished
by modifying the structure of the formed-in-place membrane.
For these applications, the pores of the membrane are
reduced, resulting in higher retentions of smaller components
as well as a reduction in the flux (throughput) of the system.
To compensate for the reduced flux, either additional
membrane modules can be added or more time will be
required to accomplish the remediation. In either case, the
overall cost may be higher.
The SBP system may be most suitable to treating relatively
dilute, but toxic, wastestreams in which the percent reduction
of contaminants will allow discharge of the permeate without
further treatment. This feature makes the unit highly suitable
for polishing effluents as part of a multi-technology
treatment train. In this system, the primary treatment
technology can be utilized to remove the bulk of the
contamination, with the filtration unit being used as a final
polishing step.
A major attribute of the SBP system is its ability to
minimize fouling. SBP effectively controlled excessive
fouling, in spite of the problematical nature of the wood
preserving waste feed, through a combination of cross-flow
operation and membrane cleaning. The membrane cleaning
process effectively regenerated the membrane to its original
clean permeate flux conditions. This enabled the membrane
to be reused, without the necessity to reformulate.
The ability to repeatedly regenerate the flux after the
cleaning procedure is a good indication that the formed-in-
place membrane is stable and can be used over an extended
length of time. In the unlikely event of an irreversible
fouling, the membrane can be cost-effectively and easily
reformed on-site with a minimum of downtime.
SBP uses a proprietary formed-in-place membrane
technology. The membrane is formed on porous sintered
stainless steel tubes by depositing microscopic layers of
inorganic and polymeric chemicals. The properties of the
formed-in-place membrane can be varied by controlling the
type of membrane chemicals used, their thickness, and the
number of layers. This important feature allows for
customization of the membrane system to a wide variety of
waste characteristics and clean-up criteria. The formed-in-
place membrane can be quickly and economically
reformulated in the field to accommodate changes in waste
characteristics or treatment requirements.
-------
The formed-in-place membrane is compatible with a wide
variety of contaminants often encountered in hazardous
wastewater streams. The SBP formed-in-place membrane is
stable under most chemical environments and will not
degrade even at high contaminant concentrations.
The extent of contaminant reduction required (overall and
for individual pollutants) can also be an important factor in
system design and operation. This will impact membrane
selection, and operational requirements such as the number
of cycles necessary to achieve the targeted volume reduction.
Generally, as the desired level of volume-reduction
increases, the overall quality of the permeate decreases, so
a balance must be maintained between throughput and
permeate quality. This will also affect the throughput
capability (as permeate) for a particularly sized system.
Other factors that could affect the removal of PAHs or other
contaminants (e.g., PCP) may include the presence of other
organics, oil and grease, suspended solids, and dissolved
solids in the feed water. While the levels of such
contamination encountered in the demonstration project had
no apparent adverse effect, it is unclear how much rejection
(of PAHs) was due to molecular size or weight and how
much was due to solubility in oil that was rejected and
coalesced by the membrane. Additional or alternative
mechanisms also may be operative.
-------
SECTION 2
INTRODUCTION
2.7 The SITE Program
The EPA's Office of Solid Waste and Emergency Response
(OSWER) and the Office of Research and Development
(ORD) established the Superfund Innovative Technology
Evaluation (SITE) Program in 1986 to promote the
development and use of innovative technologies to clean up
Superfund sites across the country. Now in its sixth year.
the SITE Program is helping to provide the treatment
technologies necessary to meet new federal and state cleanup
standards aimed at permanent, rather than temporary,
remedies. The SITE Program is composed of two major
elements: the Demonstration program and an Emerging
Technologies Program. In addition, the Program includes
research on analytical methods that can expedite cleanups at
Superfund sites.
The Demonstration Program is designed to provide
engineering and cost data on selected technologies. EPA
and the developers participating in the program share the
cost of demonstrating their innovative systems at chosen
sites, usually Superfund sites. Developers are responsible
for the operation of their equipment (and related costs). EPA
is responsible for sampling, analyzing, and evaluating all test
results and comparing these results to claims originally
defined by the developer. The result is an assessment of the
technology's performance, reliability, and cost. In addition
to providing the deveioper with carefully documented
information useful in marketing, the information, in
conjunction with other data, also will be used to select the
most appropriate technologies for the cleanup of other
S uperfund sites.
Developers of innovative technologies apply to the
Demonstration Program by responding to EPA's annual
solicitation. To qualify for the program, a new technology
must have a pilot or full scale unit and offer some
measurable advantage over existing technologies. Mobile
technologies are of particular interest to EPA.
Once EPA has accepted a proposal, EPA and the developer
work with the EPA Regional offices and state agencies to
identify a site containing wastes suitable for testing the
capabilities of the technology. EPA's contractor designs a
detailed sampling and analysis plan that will thoroughly
evaluate the technology and ensure that the resulting data are
reliable. The duration of a demonstration varies from a few
days to several months, depending on the type of process
and the quantity of waste needed to assess the technology.
While meaningful results can be obtained in a demonstration
lasting one week with some technologies, such as the SBP
formed-in-place membrane process, others, such as in-situ
bioremediation of contaminated soil, may require months.
On completion of a demonstration, EPA prepares two reports
which are explained in more detail below. Ultimately, the
Demonstration Program leads to an analysis of the
technology's overall applicability to Superfund problems.
The second principal element of the SITE Program is the
Emerging Technologies Program, which fosters the
investigation and development of treatment technologies
which are still at the laboratory scale. Successful validation
of these technologies could lead to the development of
systems ready for field demonstration. A third component of
me SITE Program, the Measurement and Monitoring
Technologies Program, provides assistance in the
development and demonstration of innovative techniques and
methods for better characterization of Supetfund sites.
-------
2.2 SITE Program Reports
The results of the SITE Demonstration Program are
incorporated in two basic documents, the Technology
Evaluation Report and the Applications Analysis Report. The
former provides a comprehensive description of the
demonstration and its results. The anticipated audience is
engineers responsible for detailed evaluation of the
technology for application to other sites and wastes. These
technical evaluators will need to understand thoroughly the
performance of the technology during the demonstration and
the advantages, risks, and costs of the technology for the
given application.
The Applications Analysis Report is directed to decision-
makers responsible for selecting and implementing specific
remedial actions at other sites. This report provides sufficient
information to enable them to determine whether the
technology merits further consideration as an option in
cleaning up specific sites. If the candidate technology
described in the Applications Analysis Report appears to
meet the needs of the site, more thorough analysis of the
technology based on the Technology Evaluation Report and
site-specific information from remedial investigations for the
site will be made. Thus, me Applications Analysis Report
helps in determining whether the specific technology should
be considered further as an option for a particular cleanup
situation and the Technology Evaluation Report provides the
detailed data for such further evaluation.
2.3 Purpose of the Applications Analysis
Report
Each SITE demonstration evaluates the performance of a
technology while treating a portion of the particular waste at
the demonstration site. Additional data from other projects
also will be presented where available, although such results
often lack the quality control and quality assurance imposed
during the SITE evaluation and, consequently, cannot be
used with the same confidence.
Usually the waste at other sites being considered for
remediation will differ in some way from the waste tested in
a demonstration. These differences may affect waste
treatability and use of the demonstrated technology at such
other sites. Successful demonstration of a technology at one
site does not assure that a technology will work equally well
at other sites. To the extent possible during the
demonstration, the operating range over which the
technology performs satisfactorily is established by
examining a broad range of wastes and sites. To a limited
extent, this report provides an indication of the breadth of
applicability of the SBP membrane filtration system by
examining not only the demonsuation test data but also data
available from other applications of the technology.
To encourage the widespread use of demonstrated
technologies, EPA will evaluate the probable applicability of
each technology to sites and wastes in addition to those
tested, and will study the technology's likely costs in these
applications, identifying unique characteristics that make the
demonstrated technology either attractive or unattractive. The
results of these analyses will be summarized and distributed
to potentially interested parties through the Applications
Analysis Report.
2.4 Process Description
SBP's membrane technology can be used as an integral part
of a remediation system to significantly reduce the volume
and toxicity of contaminated wastewater. The technology is
particularly suited for the treatment of contaminated
groundwater as part of a pump and treat system. The
technology reduces risks to human health and the
environment by transferring the contaminants to a smaller
volume facilitating destruction or detoxification by other
technologies.
SBP uses a proprietary formed-in-place membrane
technology. The membrane is formed on porous sintered
stainless steel tubes by depositing microscopic layers of
inorganic and polymeric chemicals. The properties of the
formed-in-place membrane can be varied by controlling the
type of membrane chemicals used, their thickness, and the
number of laj'ers. This important feature allows for
customization of the membrane system to a wide variety of
waste characteristics and clean-up criteria. The formed-in-
place membrane can be quickly and economically
reformulated in the field to accommodate changes in waste
characteristics or treatment requirements.
Contaminated feedwater is recirculated through the filtration
unit until the desired level of volume reduction is attained.
The filtration unit generates two process waste streams. A
relatively clean stream, called the "permeate", passes through
me membrane while a smaller portion of the feedwater.
retaining those species that do not pass through the
membrane, is retained in a stream called the "concentrate".
The permeate stream should be clean enough for disposal as
a non-hazardous waste with little or no additional treatment.
The concentrate would require further treatment to
immobilize or destroy the contaminants.
-------
2.5 Key Contacts
For more information on the demonstration of the SBP
Technologies Filtration System for contaminated
groundwater, please contact:
1. Vendor concerning the process:
SBP Technologies, Inc.
2155 West Park Court
Stone Mountain, Georgia 30087
404-498-6666
Dr. David J. Drahos, Director of Research & Development
2. EPA Project Manager concerning me SITE
Demonstration:
Ms. Kim Lisa Kreiton
U.S. EPA -ORD
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7328
3. State contact concerning the American Creosote Works
site:
Mr. Doug Fitton
Florida Department of Environmental Regulation
2600 Blair Stone Road
Tallahassee, FL 32399
904-488-0190
4. EPA Regional contact concerning the American
Creosote Works site:
Mr. Mark Fite
(4WD-SSRB)
U.S. EPA, Region IV
345 Courtland Street, NE
Atlanta. GA 30365
404-347-2643
-------
SECTIONS
TECHNOLOGY APPLICATIONS ANALYSIS
3.1 Introduction
This section of the report addresses the potential applicability
of the SBP filtration technology as a means of concentrating
organic contaminants in aqueous waste streams. The prime
benefit of concentrating contaminants is to minimize costly
treatment of the entire wastestream. In addition, by
concentrating the organic contaminants into a smaller
volume, alternative treatment technologies may be feasible
based on technical and/or economic criteria.
The ability of the filtration unit to concentrate organic
contamination from aqueous waste streams was demonstrated
on a groundwater contaminated with wood preserving wastes
(phenolics, PAHs, and PCP). The results from the
demonstration, in conjunction with information supplied by
the vendor, were used to assess the applicability of the
technology for a variety of waste types and site conditions.
The process uses a formed-in-place hyperfiltration membrane
on a stainless steel support to separate and concentrate
higher molecular weight contaminants. Contaminated
groundwater (feed) is pumped through the modules under
pressure. A portion of the feed passes through the formed-
in-place membrane forming a permeate. The membrane
retains certain contaminants resulting in a permeate that is
clean relative to the feed. The bulk of the contamination
remains in the "concentrate" fraction. The concentrate is
recycled through the unit until the desired concentration or
level of volume reduction is attained, or the level of
contaminants in the recycling concentrate inhibits the
filtration process (fouling). The system relies on a technique
called "cross-flow filtration" to minimize fouling of the
membrane and thus maximize throughput.
The properties of the two process streams (permeate and
concentrate) are of particular importance since these
characteristics define waste disposal options. The permeate
stream should exhibit significant reductions in contamination
so as to allow economical discharge to local wastewater
ueatment facilities without extensive pretreatment
requirements. The concentrate stream should be
volumetrically small, relative to the original feed, in order to
minimize the volume of waste requiring further treatment
prior to disposal. Furthermore, the filtration process should
enable the use of additional disposal options for the
concentrate (as compared to the raw feed).
The following subsections summarize observations and
conclusions drawn from the current study and supporting
information. Included in the discussion are factors such as
the application of membrane processes for waste water
reduction, benefits of the SBP system, other applicable waste
waters, site characteristics and constraints, applicability and
impact of state and federal environmental regulations, unique
handling requirements, and personnel factors. Additional
information on the technology, including a process
description, vendor claims, a summary of the demonstration
test results and case studies of other investigations is
provided in the Appendices.
3.2 Mechanisms of Membrane Separations
Membranes are semi-permeable barriers that are used to
isolate and separate constituents from a fluid stream. The
separation process can be accomplished through a number of
physical and chemical properties of the membrane as well as
the material being separated. Separation can occur through
processes such as size, ionic charge, solubility, and
combinations of several processes. Membranes can remove
-------
materials ranging from large visible particles to molecular
and ionic chemical species. Membrane materials are diverse
and can consist of synthetic polymers, natural fabrics, porous
metals, porous ceramics, or liquids. The surface of the
membrane can be chemically or biologically altered to
perform separations on specific chemical compounds. The
interaction of the components of the fluid stream with the
membrane is the mechanism controlling the outcome of the
separation process.
There are two basic modes of membrane separation. In
dead-end filtration specific species are trapped within the
matrix of the membrane material. The membrane "filters-
out" these species producing a relatively clean effluent. In
dead-end filtration the components that are trapped are
usually not recovered and remain within the membrane
matrix. In addition, the membrane eventually becomes
plugged necessitating the replacement of the membrane.
Dead-end filtration is principally utilized to purify a fluid in
applications where the removed species is relatively dilute.
In cross-flow filtration the fluid stream is directed parallel to
the surface of the membrane. This action inhibits the
accumulation of components within the matrix of the
membrane. The cross-flow action of the fluid keeps the
surface of the membrane clean allowing for the passage of
species smaller than the pores of the membrane. Cross-flow
filtration produces two effluent streams. The permeate is the
stream that passes through the membrane and is relatively
depleted in species larger than the pore size of the
membrane. The concentrate is the cross-flow stream that
contains the larger species that are unable to pass through
the membrane and accumulate. The concentrate can he
recycled allowing for progressive concentration of species
over time. Due to the ability of the cross-flow system to
concentrate components from the feed stream, it is
commonly used as a method to separate and recover these
components. Furthermore, the cross-flow action minimizes
plugging of the membrane (fouling) by constantly sweeping
the membrane's surface. This cleaning action extends the
life of the membrane and minimizes degradation of flow
through the membrane.
Membrane systems have many applications for the pre-
treatment and treatment of hazardous wastes. Membrane
separation is a volume reduction technology. This
technology can separate and concentrate specific
contaminants from a waste stream, resulting in a significant
reduction in the volume of waste requiring treatment. The
concentrated contaminants can then be destroyed or rendered
non-toxic. The utility of a membrane based technology is
based on its ability to reduce the volume of waste by
removing contaminants from the feed stream and producing
an effluent stream that would require little or no further
treatment. The greater the volume reduction, the more
effective the technology is in reducing ultimate disposal
costs. However, there is a balance between the magnitude
of the volume reduction, the quality of the effluent stream.
and the size and operation of the unit. A higher volume
reduction would require additional recycling, reducing the
overall flow through the system. In addition, higher levels
of contaminant removal will usually result in lower fluxes
through the membrane requiring either more membrane area
or longer processing time. The balance between throughput
and effluent quality is dictated by clean-up standards and
treatment costs. This balance will impact such factors as the
size and type of the equipment, mode of operation, time
required for remediation, treatment requirements for the
permeate, and ultimate disposal mechanism for the
concentrated contaminants.
3.3 Applications of Membrane Processes for
the Treatment of Hazardous Wastes
Membrane processes have many applications in the treatment
of contaminated waste streams. The most common
applications involve the removal and concenuation of
organic and inorganic contaminants from liquid waste
streams. The waste streams can originate from industrial
processes, contaminated groundwater. contaminated surface
water bodies, or as by-products of other treatment processes.
Membrane and filtration processes have historically been
utilized for the treatment and purification of drinking water.
For this application, filtration is used to remove a wide
variety of constituents, ranging from visible particulates
(sand filters) to ionic species (reverse osmosis). From these
conventional applications, new uses of membrane separations
have recently been applied to the treatment of hazardous
waste streams.
Membranes can be used to separate and concentrate organic
contaminants from waste streams. In these applications, the
organic contaminants are removed based on their size
(molecular weight) or polarity. Size separations rely on
membranes with specific pore size distributions. The smaller
the pores, the greater will be the removal of small molecular
weight compounds. However, as the membrane's pore size
decreases, the flux (flow per unit membrane area) also
decreases impacting the overall economics and efficiency of
the process. The polarity of an organic constituent is a
measure of it's ability to ionize in solution. Examples of
polar molecules are water, alcohols, and compounds with
hydroxyl (e.g. phenols) and carboxyl groups (e.g. organic
-------
acids). Aliphatic hydrocarbons and polynuclear aromatic
hydrocarbons are examples on non-polar organic molecules.
The chemical characteristics of the membrane can be used
to separate non-polar constituents in a waste stream from
polar constituents. For example, a membrane whose surface
is hydrophilic will allow passage of polar components while
retaining the non-polar components. These membranes can
be used to separate dissolved and emulsified oils from
aqueous waste streams.
Inorganic contaminants, such as salts and heavy metals, can
be removed and concentrated from waste streams by
membrane processes. Suspended inorganics can be easily
removed through the use of microfiltration membranes.
These membranes have pore sizes ranging from as low as
0.01 \un to several microns. Dissolved inorganics can be
removed either through the use of hyperfiltration (reverse
osmosis) membranes, or by precipitation followed by
microfiltration. Conventional reverse osmosis membranes
may require extensive prefiltration to avoid fouling, and
therefore can only be used on relatively clean feed solutions.
Chemical precipitation, followed by microfiltration, allows
for the use of microfilters which exhibit higher fluxes and
are not as sensitive to fouling.
Membrane processes can be helpful in solving many
remediation problems at hazardous waste sites.
Contaminated Groundwater
Containment and/or remediation of contaminated aquifers
typically utilizes pump and treat technologies to control
contaminant plume migration and ultimately restore the
quality of the groundwater. The recovered groundwater
usually requires treatment prior to discharge. Treatment
alternatives for the recovered groundwater are dependent on
the nature and extent of the contamination. Membrane
systems can be effectively used to significantly reduce the
quantity of groundwater requiring costly treatment
The contaminants of concern can be isolated and
concentrated into a reduced volume which can be more
easily handled. Another potential benefit of the
concentration process is that additional destructive treatment
alternatives may become feasible. For example, the
concentration of hydrocarbons from a contaminated
groundwater can produce a reduced volume waste with a
high BTU value allowing for fuel blending as a disposal
alternative. This not only reduces the quantity of
groundwater that must be treated, but also produces a more
easily treatable final waste product. As another example,
heavy metals can be concentrated from an aqueous stream
by membrane processes and immobilized by
solidification/stabilization technologies.
Membrane processes can be potentially used to recover
organic and inorganic constituents for recycle/reuse. In these
applications, the separation scheme must be developed to
produce a high quality concentrate.
Membrane processes can be applied to the removal of many
organic contaminants from waste streams. Organic
contaminants that can be removed include petroleum derived
hydrocarbons (benzene, toluene, ethylbenzene, xylenes),
polynuclear aromatic hydrocarbons, PCBs, dioxins/furans,
pesticides, and chlorinated hydrocarbons. Generally,
membrane process are more easily applied to removing
larger molecular weight, non-polar organic components
because larger pored membranes can be utilized and surface
chemistry interactions can augment size separations.
Removal of hazardous inorganic species from contaminated
groundwater requires a detailed knowledge of the water
chemistry in order to optimize the separation. In many
cases, addition of precipitating chemicals must be added in
order to induce particulate formation. Furthermore,
groundwater containing high concentrations of innocuous
inorganic constituents such as iron and divalent cations (egs.
potassium and calcium) may compete with and interfere with
the removal of toxic heavy metals. Conventional reverse
osmosis membranes are fragile and must be protected from
the corrosive nature of many highly contaminated aquifers.
Integration With Other Technologies
Membrane processes are particularly amenable to integration
with other remedial technologies enabling applications to
additional waste matrices. Ease of integration is facilitated
by the modular and scalable properties of membrane
systems. These systems can be readily integrated with other
remedial process equipment to enhance the effectiveness and
economy of these systems.
Membrane processes can be used as a final polishing tool for
remedial technologies involving discharge of process water.
In this capacity, the membrane system is utilized to remove
contaminants from a relatively dilute waste stream. The
benefit of using this polishing step is to avoid costly
overdesign of the primary remedial technology. For
example, a membrane system can be impiemented as a final
polishing step on a bioreactor. The bioreactor can be
designed to cost-effectively treat the bulk of the organic
10
-------
contamination, while the polishing membrane can be
designed to treat the aqueous phase prior to discharge.
Membrane processes can be used as a pie-treatment step for
other remedial technologies. The purpose of the pre-
treatment would be to concentrate the contaminants to a
level that is amenable for specific remedial technologies.
For example, organic contaminants in dilute aqueous
streams (e.g. groundwater, leachate) can be concentrated to
a level that could support an efficient biomass for
bioremediation technologies.
Membranes can be integrated with remedial technologies as
a component in the process. For example, membranes can
be used to recycle and recover extraction fluids used to
concentrate organic and inorganic contaminants in soil
extraction technologies.
3.4 Features ofSEP's Hyperfiltration System
The SBP Hypetliltration system has several unique features
which provides advantages over conventional membrane
processes in wastewater treatment applications. The
demonstration was designed to evaluate these features under
actual remediation conditions.
Formed-In-Place Membrane
SBP uses a proprietary formed-in-place membrane
technology. The membrane is formed on porous sintered
stainless steel tubes by depositing microscopic layers of
inorganic and polymeric chemicals. The properties of the
formed-in-place membrane can be varied by controiling the
type of membrane chemicals used, their thickness, and the
number of layers. This important feature allows for
customization of the membrane system to a wide variety of
waste characteristics and clean-up criteria. The formed-in-
place membrane can be quickly and economically
reformulated in the field to accommodate changes in waste
characteristics or treatment requirements.
Conventional membranes rely on rigid polymeric, ceramic,
or porous stainless steel membranes. These membranes are
available in discrete pore sizes and cannot be customized to
the characteristics of the feed. Furthermore, once installed
on-site it is difficult and costly to modify their separation
properties in response to variable feed characteristics.
The formed-in-place membrane is compatible with a wide
variety of contaminants often encountered in hazardous
wastewaterstreams. Many conventional reverse osmosis
membranes are made from materials such as cellulose
acetate and exhibit poor compatibility with reactive
substances often encountered in hazardous wastes. These
conventional membranes will degrade and become
inoperative when challenged with many organic compounds.
The compatibility problem becomes more critical as the level
of concentration increases. The SBP formed-in-place
membrane is stable under most chemical environments and
will not degrade even at high contaminant concentrations.
Fouling Control
A major limitation of many membrane systems is their
propensity to irreversibly foul. Fouling is the uncontrolled
build-up of materials on the surface of the membrane.
Fouling leads to a loss of flux and eventually results in
cessation of flow. If a membrane fouls, it must be cleaned
in order to restore flux. If cleaning is unsuccessful, then the
membrane is replaced.
SBP utilizes a cross-flow filtration mechanism to
continuously clean the surface of the membrane, hence
minimizing fouling. In this mode, the feed stream is
directed parallel to the membrane's surface resulting in a
cleaning action which minimizes the buildup of materials on
the membrane's surface.
Since all membranes eventually foul, a cleaning cycle is
necessary to restore flux and operability. Many membrane
systems have limited abilities to be regenerated due to
restrictions in the choice of cleaning chemicals. The SBP
formed-in-place membrane is compatible with a wide range
of chemical cleaning methods, enabling in-place regeneration
of flux. In situations where the membrane becomes
irreversibly fouled, the formed-in-place membrane can be
stripped and reformulated on-site.
3.5 Demonstration Results
The results of the demonstration test program at the
American Creosote Works site provides information relevant
to the application of SBP's technology to other waste types
and sites.
SBP's membrane technology can be used as an integral part
of a remediation system to significantly reduce the volume
and toxicity of contaminated wastewater. The technology is
particularly suited for the treatment of contaminated
groundwater as part of a pump and treat system. The
technology reduces risks to human health and the
environment by transferring the contaminants to a smaller
volume facilitating destruction or detoxification by other
technologies.
11
-------
The system is simple to operate, reliable and requires a
minimum of operator attention or maintenance once the
membrane has been formed. The stability of the system
makes it particularly suitable for long-term use as is
necessary for extended pump and treat remedial programs.
The demonstration at the American Creosote Works was
designed to evaluate the two most critical process parameters
for membrane systems; volume reduction and contaminant
reduction. A summary of the demonstration results for these
critical processes parameters are presented below. A
discussion of the demonstration results and process
performance, as they relate to applicability to other wastes
and sites, follows in the subsequent chapter.
Volume Reduction
The claim that the system can be operated to recover 80%
of the feedwater volume as permeate was achieved. Average
water recovery (volume reduction) for the first five runs was
83%. The volume reduction for the extended run (day six)
was 96%, and represents the maximum volume reduction
capability of the unit for the waste stream tested.
Contaminant Reduction
The process did not achieve the developer's claim of 90%
overall removal of the semivolatiles present in the feedwater
(on the average, a 74% reduction was achieved). However,
the process does effectively remove polynuclear aromatic
hydrocarbons from the feedwater and place them in the
concentrate. Overall, removal of polynuclear aromatic
hydrocarbons averaged 92%. Removals of individual PAHs
range from 78% to well over 94% for individual two, three,
and four ring PAHs.
Other high molecular weight pollutants, such as oils and
dioxins, are also rejected from the permeate with high
efficiency (93% for oils and >99% for dioxins). However,
removal of low molecular weight phenols is much less
effective, with values between 15 and 21%.
Depending on how a system is used, i.e.. level of volume
reduction and quality of permeate, operating plus capital cost
could be as low as $200/1,000 gallons. Capital cost for an
averaged size system is approximately $300,000.
3.6 Discussion of Demonstration Results and
Applications
The results and observations from the SITE demonstration,
coupled with information supplied from the vendor, is used
to discuss the applicability of SBP's membrane technology
to the treatment of organic contaminated wastewater. The
SITE demonstration was designed to evaluate the innovative
features of SBP's process as a volume reduction technology.
The SITE demonstration took place at the American
Creosote Works in Pensacola, Florida and utilized
groundwater contaminated with creosote and
pentachlorophenol. Creosote was chosen as a testing
material for two reasons.
1. Creosote is a complex mixture of over 250
individual compounds, dominated by polynuclear
aromatic hydrocarbons and phenolics, and exhibits
a wide range of chemical and physical properties.
The wide molecular weight distribution of the
organic contaminanta is an excellent challenge
material for a membrane process, allowing for
analysis of removal efficiencies over a wide range
of feed characteristics.
2. Wood preserving waste contaminated aquifers
represent a significant and widespread
environmental problem. Results from this
demonstration could be directly applicable to other
wood preserving waste sites.
A pumping well recovered the creosote and PCP
contaminated groundwater from the site. The groundwater.
which contained aqueous and dense free product fractions.
was allowed to settle and the aqueous phase retained for the
study. The aqueous phase was diluted with carbon-treated
potable water in order to adjust the concentration of the
semivolatiles in the feed to fully test the concentrating
capabilities of the tiltration unit.
Contaminant Reduction
The utility of a membrane system is its ability to remove
contaminants from a wastewater stream and concentrate
them into a reduced volume. The contaminant reduction is
the percent decrease in specific contaminants from the feed
to the permeate (discharge). The higher the percent
contaminant reduction, the more effective is the membrane-
at removing contaminants from the waste stream.
12
-------
It is important to note that the applicability of the technology
cannot be made solely on the percent contaminant reduction.
Since contamination is reduced as a percentage of the
concentration in the feed, the quality of the permeate is
dependent on feed concentrations. In order to assess
applicability, the predicted quality of the permeate can be
estimated by calculating contaminant reductions from the
feed. The estimated permeate quality can then be compared
to site specific discharge standards.
For the demonstration at the ACW site, the total
concentrations of semivolatile contaminants for each run are
summarized in Table 1 for the feedwater and permeate. The
system was evaluated by comparing the total concentrations
of these compounds in the feedwater against the permeate.
Over the six day period, an average overall rejection of 74%
was achieved. Thus, starting with a feedwater containing on
the average 90 mg/L of total designated semivolatile
components, the composited permeate, accounting for 80%
of the original feedwater volume, contained on the average
23 mg/L. This did not meet the vendor's claim for 90%
removal, largely because of the noted inefficiency with
phenolics. This is not totally unexpected since the
membrane, as formulated, was not expected to remove
species with molecular weights less than 200.
TABLE 1. Feed and Permeate Semreototites - Total Concentrations and
Contaminant Reductions
Total Semivolatile Concentrations
mg/L
Feed Permeate Contaminant Reduction
Run1
Run2
Run3
Run4
Run5
Run6
104
91
92
104
85
60
18
24
26
22
23
24
83
74
72
79
73
60
A summary of the average concentrations for individual
semivolatile compounds in the feed and permeate, along with
the associated rejections, for the six day demonstration are
presented in Table 2. The results of the demonstration
indicated that the pilot unit was capable of removing over
94% of some PAHs but only 15 - 21% of the phenoiics.
The permeate generated during the process was discharged
directly to the local POTW.
These results indicate, as expected, that the membrane is
more effective in removing larger molecular weight
components (PAHs) than the smaller molecular weight
molecules (phenoiics). With a complex feed such as
creosote, it is difficult to achieve high reductions of all
components and at the same time deliver adequate
throughput. In this application, the membrane was
formulated to maximize reduction of the more toxic
poiynuclear aromatic hydrocarbons. Passage of the phenolic
compounds into the permeate did not pose a significant
disposal problem since the local POTW could accept the
phenols in their treatment system. At other sites, careful
attention should be made to local discharge requirements and
available treatment facilities.
The SBP membrane process would be most applicable to
wastewaters containing large molecular weight organic
compounds (PAHs, dioxins/furans, polychlorinated
biphenyls, and certain pesticides/herbicides). The system
can remove smaller weight molecular compounds (phenols,
benzene, toluene, ethylbenzene, xylenes) if larger molecular
weight compounds are not abundantly present. Removal of
smaller weight molecular compounds can be accomplished
by modifying the structure of the formed-in-place membrane.
For these applications the pores of the membrane are
reduced, resulting in higher retentions of smaller components
as well as a reduction in the flux (throughput) of the system.
To compensate for the reduced flux, either additional
membrane modules can be added or more time will be
required to accomplish the remediation. In either case, the
overall cost may be higher.
The SBP system may be most suitable to treating relatively
dilute, but toxic, wastestreams in which the percent reduction
of contaminants will allow discharge of the permeate without
further treatment. This feature makes the unit highly suitable
for polishing effluents as part of a multi-technology
treatment tram. In this system, the primary treatment
technology can be utilized to remove the bulk of the
contamination, with the filtration unit being used as a final
polishing step.
If the concentration of contaminants in the permeate does
not meet clean-up requirements, then the permeate can be
recycled back through the membrane to achieve the targeted
effluent quality. Recycling of the permeate has the
disadvantage of requiring additional membrane modules, or
additional time, both of which increase treatment costs.
A number of mechanisms could explain the contaminant
reduction results, including rejection by the membrane on the
basis of molecular weight or molecular size, rejection and
coalescence of dispersed oil in which specific components
13
-------
are soluble, or even rejection simply by adsorption of the
PAHs on inert suspended solids.
Examination of the results for the conventional parameters
tested in the feed and permeate (Table 3) provides some
insight into the separation mechanism. High concentrations
of oil and grease found in the feedwater suggests that
considerable oil remained in a dispersed or colloidal form.
This oil would be removed by a membrane with
ultrafiltration or hyperfiltration characteristics. Since the
PAHs are more soluble in oil than in water, concurrent
removal of the PAHs entrained within the oil may have
occurred. The phenols with relatively high solubility in
water are, also as expected, removed more poorly. This also
is reflected in the poor rejections calculated for TOC and
COD. Other contaminants, not quantified by the semivolatile
analysis, also may contribute to the high TOC and COD in
the permeate.
TABLE 2. Individual Semivolatile Concentrations and Rejections (average of
six daily runs)
TABLE 3. Conventional Parameters
ANALYTE
Phenol
2-Methyl phenol
4-Methyl phenol
2,4-Dimethyl phenol
Benzole Acid
Pentachlorophenol
Naphthalene
2-Methyl Naphthalene
Acenaphthylene
Acenaphthene
Dibeazofuran
Fhiorene
Fhenanthrene
Anthracene
Flnoranthene
Pyrene
Benzo(a) anthracene
Cluyseue
Benzo(b) flnoranthene
Benzo(k) flnoranthene
Benzo(a)pyrene
FEED
(mg/L)
4.90
2.31
6.92
1.82
(1 .42)
(2.42)
12.67
4.52
(0.14)
6.64
4.86
5.92
17.06
1.96
7.01
4.70
1.24
1.13
(0.«D
«M9
(0.31)
PERMEATE
(mg/L)
3.66
1.93
5.75
1.54
2.16
1.88
2.87
0.46
(0.02)
0.51
0.41
0.37
0.59
0.07
0.10
0.05
'0.03
'0.03
'0.03
'0.03
'0.03
REJECTION
(%)
20.6
16.5
16.9
15.4
a
a
77.7
89.6
a
91.7
91.6
93.6
96.6
36.5
96.6
36.9
>97.6
>97.4
a
a
a
Values in parentheses represent analytes with estimated values that are above instrument I limits
but below quantitation limits
' Analytes not delected are presented ty an ', and the values represent one-fialf fle
quantitation limit.
a -Individual refections not calculated due to estimated values.
Analyte
Feed
(mq/L)
Permeate
(mg/L)
Rejection
%
Average of six runs
IDS
TSS
237
34
OIL/GREASE 191
TOC
COD
Volume
121
379
Reduction
190
<4
14
92
362
20
>88
94
24
7
The utility of a membrane separation system for treating
hazardous wastestreams is also dependent on the magnitude
of volume reduction. The volume reduction is a measure of
the percent of the feed water that can be generated as
cleaner permeate. The higher the volume reduction, the
greater the potential utility of the membrane system.
Volume reduction cannot be solely used as an indicator of
membrane performance. The quality of the permeate must
also be considered when evaluating the applicability of the
technology. A high volume reduction with low permeate
quality is not acceptable since the permeate will not be
dischargeable and will require further treatment. When
designing a membrane separation system, volume reduction
and permeate quality must be balanced in order to develop
a cost-effective treatment meeting site-specific clean-up
criteria.
For the six-day demonstration at the American Creosote
Works an 80% volume reduction was achieved each day.
This level of volume reduction was set as a target prior to
the demonstration and was easily attained. The level of
volume reduction was achieved by continuously recirculating
the concentrate through the system. On the last day of
operation the process was allowed to run until the unit could
no longer function, representing the maximum volume
reduction for that feed. The maximum volume reduction
was 96%.
The relationship between volume reduction and permeate
quality is exemplified by results from the demonstration.
During the six day demonstration, grab samples of the
permeate stream were collected at the beginning, middle, and
end of each run. The purpose of these samples is to
document changes in permeate quality during the course of
the batch filtration. The analysis of the data reveals an
increase in total semivolatile content of the permeate from
the beginning to the end of each run. Six day average
permeate concentrations of total semivolatiles were 19.24
14
-------
mg/L at the beginning of the run, 24.17 mg/L in the middle,
and 29.95 mg/L at the end of the run. In addition, on day
six, when the unit was allowed to run to a maximal volume
reduction of 96%, the final permeate semivolatile
concentration was 47.25 mg/L.
These changes in permeate quality during the filtration are
due to increasing semivolatile contents of the recirculating
concentrate. As the batch filtration proceeds, the surface of
the membrane is challenged with progressively higher
concentration of contaminants. Since the membrane can
only reject a certain proportion of the feed stream, the
concentration of contamination in the permeate will increase.
When applying a membrane solution to a wastewater
problem it is crucial to evaluate the balance between
permeate quality and volume reduction. Maximizing volume
reduction is important since it impacts economics by
minimizing the volume of wastewater requiring treatment.
However, the quality of the discharged water is critical and
must be maintained during the filtration process. Treatability
testing is necessary to determine the optimal balance
between permeate quality and volume reduction.
Fouling Control
Fouling is the loss of flux due to the buildup of components
on the surface of the membrane. All membranes exhibit
some degree of fouling and eventually require cleaning to
restore flux. Many membranes foul readily and are not
amenable to cleaning for flux restoration. If flux cannot be
restored, then the membrane must be replaced resulting in
considerable expense and downtime.
A major attribute of the SBP system is its ability to
minimize fouling. SBP effectively controlled excessive
fouling, in spite of the problematical nature of the wood
preserving waste feed, through a combination of cross-flow
operation and membrane cleaning. Flux and pressure data
collected during the demonstration indicated gradual and
slight fouling of the membrane. This slight fouling was
reversed after each two-run cycle by a membrane cleaning
procedure. Analysis of the washwaters from the cleaning
process indicated that approximately 8% of the mass of
semivolatiles remained in the system and were removed
during the washing process. The membrane cleaning process
effectively regenerated the membrane to its original clean
permeate flux conditions. This enabled the membrane to be
reused, without the necessity to reformulate.
The ability to repeatedly regenerate the flux after the
cleaning procedure is a good indication that the formed-in-
place membrane is stable and can be used over an extended
length of time. In the unlikely event of an irreversible
fouling, the membrane can be cost-effectively and easily
reformed on-site with a minimum of downtime.
Operational Reliability and Implementability
Operational reliability and implementability is important in
deciding the applicability of the technology to other
wastestreams and sites. Experiences from the Demonstration
represent the most extensive compilation of operability data
for the SBP system at a hazardous waste site.
The system proved to be quite stable and required a
minimum of attention over the six days of study. System
performance was relatively constant during the six day test.
With feed concentrations of total semivolatiles ranging from
60.4 to 103.8 mg/L, the percent rejection averaged 74%.,
with a narrow standard deviation of 7.5. SBP Technologies
was able to reproducibly achieve targeted volume reductions
of 80%. Other than adjustment of the pressure to maintain
flux and the cleaning of the unit, which consumed about 2
hours every other day, there was little need for an operator.
In a commercial installation some means of on-line
monitoring (eg., changes in pressure, contaminant
concentration, etc.) could alert the operator to out-of-
specification operation or out-of-compliance permeate. It is
estimated that the unit could be run by two operators (health
and safety requirements). Additional units could easily be
operated by the existing personnel.
Other than the cleaning operation every other day, there was
no downtime during the demonstration. With the exception
of the pump there are no moving parts to break down or
require service.
The process equipment and supplies for the system are
commercially available. This includes the filtration modules.
membrane forming chemicals, pumps, tanks, process
controls, gauges, and flowmeters.
The membrane formation procedure requires a high level of
expertise and may require trial and error methods to achieve
the desired separation characteristics. However, these are
not obstacles to implementation since the process is
inexpensive and rapid.
The process is easily scalable and can be modified by adding
or deleting modules in response to processing requirements.
15
-------
The addition of modules does not affect the mode of
operation, except for additional support equipment (pumps,
tanks, plumbing).
Based on the observations from the demonstration, it is
feasible that the membrane system can be effectively and
reliably operated over an extended time period as would be
necessary for pump and treat remediations.
3.7 Applicable Wastes
While this study of the SBP Hype&ration Unit was limited
to a single wastewater, the groundwater available at the
American Creosote Works site, the results of the study along
with other results provided by the vendor suggest that the
technology would have applicability to other contaminated
groundwaters and process waters. The developer believes the
system can treat wastes with 100 to 500 mg/L of COD
where the molecular weight of the contaminants to be
concentrated are over about 200. However, the
characteristics of the membrane can be modified to treat
smaller molecular weight compounds. More dilute feedwater
will necessitate additional cycles to achieve the desired
concentrations in permeate and concentrate streams.
However, the more dilute feedwaters would also allow for
higher fluxes. Other than having an impact on cost and
throughput, this should not adversely affect operation.
Wastestreams exceeding the target concentration range (100
- 500 mg/L COD) would require reduced cycling to achieve
the required level of concentration. The effect of elevated
feedwater concentrations on the rejection of individual
components may also need to be determined by laboratory
resting. Data from this study indicates ,a reduction in
permeate quality as the concentration of the feed increases.
Based on the results obtained at the ACW site with the
membrane formulated to treat wood preserving wastes, the
composition of the groundwater can determine the
applicability of the system. Groundwater rich in PAHs would
probably be suitable while feedwater where smaller
molecular weight compounds are a major pollutant would
probably not be appropriate. However, the vendor claims
that membranes could be formulated to separate small
molecular weight species (BTEX) such as those found in
hydrocarbon contaminated wastewaters (see Appendix B).
Since the former wood-preserving facility had not used the
newer chromated copper arsenate preservative, no
information on the removal of metallic contaminants was
obtained.
Cross-flow filtration using the formed-in-place membrane
may also be applicable to other wastestreams containing
different high molecular weight organic contaminants. This
might include polychlorinated biphenyls (PCBs) as might be
encountered from a spill from a PCB transformer leak,
particularly since the same preferential solubility in oil noted
earlier may prevail. On the same basis, the system may be
useful for separating other emulsified or dispersed organics
which do not lend themselves to simple physical phase
separation. The system is also well suited to significantly
reduce the concentration of dioxins and furans in wastewater.
Reduction of dioxins/furans encountered in this
demonstration was greater than 99.9%.
The developer believes the membrane can be customized to
achieve different rejection characteristics that could be
applied to a wide range of contaminants (see Appendix B).
3.8 Site Characteristics
The pilot-plant unit used in the demonstration program
required a level base large enough to accommodate the unit,
and storage tanks for the feed, concentrate, and washwater.
As was used for the SITE demonstration, a covered concrete
pad is recommended to protect the equipment from the
elements as well as contain the accidental release of
contaminated materials.
Clean water and power were the only utilities needed. If
necessary, the relatively small amount of clean water needed
for washing of the membrane could be trucked in and
power for the compressor could be provided by an on-site
generator. While it was not studied, it may be practical to
use permeate for washing. Where the unit was being used to
treat groundwater, power also would have to be provided for
the well pumps.
Acquisition of groundwater for the unit may require the
development of an extraction well network, consisting of the
appropriate pumps, regulators, and plumbing.
Permit requirements and the mode in which the filtration
unit is operated may make it necessary to have additional
space for storage tanks for equalization of the permeate until
analyses can confirm acceptability for the POTW or surface
water body discharge.
3.9 Environmental Regulation Requirements
Anticipating that the SBP system would be used on
groundwater at a contaminated site, concerns would be local
16
-------
well-drilling requirements and storage of pumped
groundwater. Depending on the size of these wells, their
productivity, and the capacity of the treatment system being
installed, storage tanks may be needed as a reservoir, to
separate free oil (if needed), and to provide equalization of
feed and permeate. Such tanks must meet regulatory
requirements for design (permits, materials, etc.), consistent
with their size and placement.
Discharge of the permeate to a POTW would certainly
require a NPDES/pretreatment permit (or state equivalent).
Depending on the operational mode used, the permit may
require continuous monitoring. This would prevent
averaging of high concentrations of contaminants in the
permeate late in a cycle with the low concentrations during
the early stages. Permits that allow equalization or
compositing of permeate during a cycle would be less
restrictive.
The reject stream (concentrate) from the filtration process
will contain elevated concentrations of the higher molecular
weight contaminants. In the case of creosote, these will
largely be PAHs. several of which are considered
carcinogenic. Consequently, the concentrate will probably
have to be considered hazardous and any subsequent
treatment could require that the facility have a "Treatment,
Storage, and Disposal" permit.
The washwater generated will also need to be addressed.
Since it contains me same PAH (and phenolic) constituents,
it too will be hazardous. Because of the chemicals added,
recycle into the concentrate or disposal with the concentrate
may not be possible unless pretreated.
Additional regulations approved in 1991 under the "Third
third" rule of the Resource Conservation and Recovery Act
of 1976 (RCRA) and the Hazardous and Solid Waste
Amendments of 1984 (HSWA) lists certain wood preserving
wastes as hazardous (F032, F034. F035). Required
treatment for these wastes has not yet been defined. In
addition, RCRA and HSWA could also designate the
permeate, the concentrate, the washwater. and any other
wastes subsequently generated as a residual from a
hazardous waste under the "derived from regulation".
Consequently, these streams also would be considered
hazardous. A recent court decision leaves the interpretation
of this matter unclear at this time.
Under the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) and the
Superfund Amendments and Reauthorization Act of 1986
(SARA), EPA is responsible for determining the methods
and criteria for the removal of contamination from a
Superfund site. The utility and cost-effectiveness of the SBP
filtration unit as one segment of a treatment system would,
to an extent, be dependent on the final level of remediation
deemed appropriate and necessary at a particular site by
EPA. However, since the use of remedial actions by
treatment that ". ..permanently and significantly reduces the
volume, toxicity, or mobility of hazardous substances" is
strongly recommended (Section 121 of SARA), inclusion of
the SBP filtration system could be attractive as part of the
remediation for a site contaminated with wood preserving
chemicals.
Chlorinated dioxins/furans are known to be produced during
pentachlorophenol manufacture. Limited testing during this
demonstration indicated that low concentrations of certain of
these materials, particularly the octa isomers, were present
in the groundwater and were concentrated in the concentrate.
The highly toxic 2.3,7,8-tetrachlorodioxin (TCDD) was not
found. Subsequent treatment or disposal of the concentrate
would need to address this matter in more detail.
3.10 Materials Handling Requirements
Materials handling requirements for the SBP unit involve
1) the acquisition of feed material for the unit,
2) pretreatment. and 3) residuals (permeate and concentrate)
management.
Acquisition of Feed
If the SBP filtration unit is part of a system used to treat
groundwater, the first need is a well drilling rig to provide
the well(s) from which the feedwater is to be obtained. Once
the wells are drilled and developed, each must be equipped
with a pump to draw up the necessary feed water. Local well
drilling requirements would have to be taken into
consideration.
Pretreatment
At some sites pretreatment may be necessary (as it was at
this site) to remove free oil and even suspended solids. Since
the developer has indicated that the filtration unit is most
effective when operating with a feed water having a COD
range of 100 -500 mg/L and is most effective in rejecting
materials with molecular weights greater than about 200.
pre-testing will be necessary to assure that these
requirements are consistently met. If the vendor's system is
provided with relatively clean ground- or process water, no
pretreatment may be necessary.
17
-------
Permeate Disposal Options
The applicability of this membrane technology at a site is
dependent on the quality of the permeate, site-specific
discharge criteria, and the availability and accessibility of
local public or industrial wastewater treatment facilities. It
is important to conduct a treatability study to assess the
quality of the permeate and to determine options for
disposal. If the permeate quality is not amenable for
discharge to surface waters or local treatment facilities, then
the technology is not applicable to the site.
Prior to the initiation of the demonstration at the ACW site
in Pensacola, a limited filterability test was conducted on
contaminated groundwater to determine if the permeate
would be accepted by the local POTW. The permeate was
subjected to biological testing (Ceriodaphnia) and chemical
analysis to determine its suitability for discharge. The
permeate passed the local POTW's criteria and was directly
discharged to a local sewer hook-up.
Several additional options are available for permeate disposal
and are dependent on waste and site conditions, as well as
local discharge regulations and treatment options.
. The permeate quality may meet local standards for
direct discharge to local surface water bodies. This
would occur only if the level of contaminants in the
permeate was extremely low and meeting the strict
requirements for surface discharge.
. The permeate could be treated on-site with additional
treatment equipment to reduce contaminant levels for
either surface water body discharge or sewer discharge.
Treatment, such as with activated carbon, may be
necessary to reduce contamination to acceptable limits.
The use of additional treatment equipment will increase
remediation costs and may necessitate additional
disposal requirements.
. The permeate may be recycled through the filtration
unit, or processed through a smaller unit, to further
reduce contaminants for surface water body or sewer
discharge. The secondary filtration unit may have
different membrane characteristics as the primary unit
to remove species that were not retained or require
greater reductions. This option would also add to the
overall cost of the remediation since additional
equipment and time would be required.
. If it is not feasible to reduce contaminant concentrations
to levels adequate for on-site discharge, and if no local
sewer hook-up is accessible, then it may be necessary
to transport the permeate by tanker truck to an
acceptable treatment facility. This option would only
be economically feasible if the membrane process
drastically reduced the volume of a wastestream that is
very costly or difficult to treat (e.g. dioxin contaminated
wastewater).
Concentrate Disposal Options
The SBP membrane process minimizes the quantity of waste
requiring extensive treatment by concenuating the
contaminants into a reduced volume while producing a
cleaner permeate for discharge. Since the contaminants are
not desuoyed by the process it is necessary to consider
disposal options for the reduced volume concentrate stream.
If the treatment options for the concentrate stream do not
reduce overall treatment costs or provide a reduction in risk
to human health and the environment, then the membrane
system is not a feasible remedial technology.
Optimally, a disposal option that can permanently destroy or
immobilize the contaminants in the concentrate stream on-
site is preferable to off-site transportation and disposal.
A portion of the concentrate from the SITE demonstration
was utilized by SBP to develop a bioremediation technology
that could be coupled co the filtration unit to produce a
treatment system for on-site destruction of a major portion
of the waste. The system uses a two-stage bioreactor
containing several naturally occurring strains of soil bacteria
capable of mediating PAH and PCP contamination. SBP
uses the membrane system' to reduce the quantity of
wastewater input into the bioreactors and to optimize
contaminant concentrations to support the biomass. The use
of the concentrate as a feed to the bioreactors extends the
utility of this volume limiting technology by reducing the
volume of wastewater that must be processed, therefore
reducing equipment costs and site space requirements. The
results from SBP's bioremediation studies are presented in
Appendix B.
Additional disposal options available for the concentrate
stream are discussed below.
The concentration process enhances the calorific value
of most organic wastes. This enables the utilization of
thermal technologies as a means of destroying the
organic contaminants. The feasibility of using and
choosing a thermal technology is based on the nature of
the organic contaminants. Concentrates from petroleum
18
-------
based contamination could be readily used for fuel
blending, while concentrates from other sources (such
as wood preserving wastes) would require careful
testing to determine selection of the appropriate thermal
technology. Thermal destruction could be accomplished
on-site (mobile units) or transported off-site.
Concentrates containing highly toxic constituents, such
as PCBs and dioxins/furans. which are not amenable to
biodegradation or thermal treatments, can be chemically
neutralized by processes such as dechlorination. The
neutralized waste could then be disposed of in a
conventional manner.
3.71 Personnel Issues
The system requires little attention once operation is
underway. Flux must be maintained by manually adjusting
pressure. In a larger-scale system, this could be
accomplished automatically. Similarly, the transfer of
concentrate back to the feed side of the unit would be
automated, requiring an operator only to monitor the
permeate quality and flux. Washing of the system with clean
water every two days required about 2 hours. The
frequency of washing can vary with the waste and the
operating mode. It is estimated that two operators would be
necessary, primarily for health and safety concerns.
In order to assure protection of workers during the
remediation, all on-site personnel should have an OSHA 40
hour health and safety training and an annual 8-hour
refresher course.
3.72 Potential Community Exposures
Contaminant exposure to the community from the SBP
filtration unit is minimal. Potential community exposure
may occur during the filtration of volatile organic
compounds and can be contained through the implementation
of emission control equipment. Potential exposure of
contaminants could occur from the accidental discharge of
waste and process water from the equipment and well
distribution network. This could be minimized by placing
all tanks and equipment on containment structures, and
utilizing leak detection systems for plumbing.
19
-------
SECTION 4
ECONOMIC ANALYSIS
4.7 Introduction
The primary purpose of this economic analysis is to estimate
costs (excluding profit) for commercial-scale remediation
using the SBP filtration unit. With realistic costs and a
knowledge of the bases for their determination, it should be
possible to estimate the economics for operating similar-
sized systems at other sites utilizing scale-up cost formulas.
Among such scale-up cost formulas available in the literature
for chemical process plant equipment is the "six-tenths rule".
The six-tenths rule is an exponential method for estimating
capital costs from existing equipment costs. If the cost of a
piece of equipment of size or capacity q, is C,, then the cost
of a similar piece of equipment of size or capacity q2 can be
calculated from:
The value for n in this study was taken as 0.6.
it was assumed that the performance of commercial-scale
equipment will be the same as that demonstrated here. This
economic analysis is based on assumptions and costs
provided by SBP, on results and experiences from this SITE
demonstration, and on best engineering judgement as
practiced by the authors. The results are presented in such
a manner that if the reader disagrees with any of the
assumptions made here, other conclusions can be derived
irom such other assumptions.
Certain actual or potential costs were omitted because site-
specific engineering aspects beyond the scope of this SITE
project would be required. Certain functions were assumed
to be the obligation of the responsible party or site owner
and also were not included in the estimates.
Cost figures provided here are "order-of-magnitude"
estimates, generally +50%/-30%, and are representative of
charges typically assessed to the client by the vendor,
exclusive of profit.
An economic analysis for the remediation of a hypothetical
site is presented in sub-section 4.6. This exercise
demonstrates the application of the costing information
derived from this study to a realistic remediation scenario.
4.2 Conclusions
The total annual cost to operate a 12-module filtration unit
ranges between 35 14.180 and $1,209,700, depending on
whether effluent treatment and costs are considered, the
flow rate through the unit, the cleanup requirements, and
the cost of effluent treatment and disposal (if required).
Effluent treatment and disposal costs, if considered, could
account for up to 60% of the total cost. Labor can
account for up to 40% of total annual costs. Processing
costs are more dependent on labor costs than equipment
costs.
The cost per 1,000 gallons can be broken down by flow
rate as follows (for with and without effluent treatment
and disposal costs):
With Effluent Treatment Costs
24 cpm 12 gpm 7.2 gpm
$228-522/1,000 gal $456-1,044/1,000 gal $760-1,739/1,000 gal
20
-------
Without Effluent Treatment Costs
24qpm 12gpm 7.2 qpm
$222/1.000 gal $444/1,000 gal $739/1,000 gal
As expected, the cost category having the largest impact
and variability on total cost was effluent treatment and
disposal.
4.3 Issues and Assumptions
This section summarizes the major issues and assumptions
used to evaluate the cost of SBP's filtration unit. In general,
assumptions are based on information provided by SEP.
Certain assumptions were made to account for variable site
and waste parameters and will, undoubtedly, have to be
refined to reflect site-specific conditions.
System Design and Performance Factors
The SITE demonstration used a four-module filtration unit.
For a full-scale remediation, twelve of the same modules
instead of four would be used with a portable generator for
power, a mix tank, and a single pump and motor.
No assumptions as to the site size or volume of waste to be
treated were made. It was assumed that the same unit would
be operated at different flow rates for a one year period to
obtain the desired results. For example, at the maximum
assumed flow rate of 24 gpm, 2.6 million gallons of waste
would be treated in 230 days of operation. The annual cost
was then divided by the volume of waste that would be
treated at a particular flow rate to obtain $/1000 gal.
days per week. The extra hour each day will be used for
cleaning and maintaining the unit. A site supervisor will
visit the site for approximately two to three days each month
for oversight purposes. The two-person crew could operate
up to three 12-module systems. If more modules are
required, additional manpower would be needed.
Utilization Rates and IMaintenance Schedules
The filtration unit was assumed to be utilized for 230 days
out of a possible 365 days a year. Scheduled maintenance
was assumed to be performed during normal operating hours.
Financial Assumptions
For the purpose of this analysis, capital equipment costs
were amortized over a 7-year period with no salvage value.
Interest rates, time-value of money, etc. were not taken into
account.
The following is a list of additional assumptions used in this
study.
Access to the site is available.
Utilities, such as electricity, water, telephone, is
easily accessible.
The permeate stream will not require further
treatment.
A hook-up to the appropriate outlet (sanitary
sewer, storm sewer, surface water body) is
available on or near the site.
There are no wastewater pre-treatment
requirements.
4.4 Basis for Economic Analysis
System Operating Requirements
No assumptions regarding percent rejection or outlet
contaminanr concentrations were made. Based on results
from the SITE demonstration, a volume reduction of 80%
between waste and concentrate was assumed. Costs per
1000 gal. treated were calculated for 24. 12 and 7.2 gpm
flow rates: the last corresponding to what was demonstrated
in the SITE program. Flow rates, the amount of recycle,
and the initial concentration of contaminants may impact
costs significantly.
One equipment operator/supervisor and one technician will
operate the unit and be on-site eight hours per day, although
the system will be operated only seven hours per day, five
In order to compare the cost-effectiveness of technologies in
the SITE program, EPA breaks down costs into 12
categories shown in Table 4 using the assumptions already
described. The assumptions used for each cost factor are
described in more detail beiow.
Site Preparation Costs
The amount of preliminary preparation will depend on the
site and is assumed to be performed by the responsible party
(or site owner). Site preparation responsibilities include site
design and layout, surveys and site logistics, legal searches.
access rights and roads, and preparations for support
facilities, decontamination facilities, utility connections, and
auxiliary buildings. These preparation activities are assumed
21
-------
to be completed in 500 staff hours, At a labor rate of
$50/hr. this would equal $25,000.
Other significant costs associated with site preparation
include construction of a pad and cover, well drilling as well
as buying and installing a groundwater pump, holding tanks,
and associated plumbing.
The cost to construct a concrete pad and cover to support the
unit and protect the unit from the elements is estimated to be
520,000.
Based on the SITE demonstration, the cost to drill a well
was assumed to be $5,000. To achieve the appropriate
maximum groundwater extraction rate of 24 gpm. three
recovery wells are required, resulting in a cost of
approximately $15,000. A 5200 gal. holding tank cost
55,000. Using the "six-tenths rule" to scale-up, the cost of
a 10,000 gal. tank for a full-scale remediation was assumed
to cost $7,400. Three tanks will be required, resulting in a
cost of $22,200. A 1/2 horse-power pump cost $1,035 for
the SITE demonstration. A pump for each well would cost
a total of $3,105. These additional costs amount to about
$40,000.
Therefore, the total site preparation costs for a full-scale
remediation would be about 385,000 as shown in Table 4.
Permitting and Regulatory Costs
Permitting and regulatory costs include actual permit costs,
system health/safety monitoring, and analytical protocols.
Permitting and regulatory costs can vary greatly because
they are very site- and waste-specific. For this cost estimate,
permitting and regulatory costs are assumed to be 5% of the
equipment costs. This assumption is based on operation at
a Superfund site. At RCRA corrective action sites
permitting and regulatory costs may be higher and an
additional 5% of the equipment cost should be added.
Equipment Costs
Capital equipment costs are for a twelve-module filtration
(unit equipped with a portable generator for power, a mix
tank, and a single pump and motor ail mounted on a trailer
with associated instrumentation, alarms and controls.
Variation in equipment costs from site to site should not be
significant. However, based on the cleanup requirements
and the material being treated, the flow rate through the
system may vary dramatically resulting in a wide range of
costs per unit treated.
Based on SBP's capital cost estimate of $300,000 for 12
modules, each module would cost $25,000.
As recommended by SBP, equipment costs were amortized
over 7 years, with no salvage value at the end of that time
period, giving an annual cost of $42,850 as shown in Table
4, without any interest factor.
SBP's filtration units are mobile and are designed to move
from site to site. Transportation costs are only charged to
the client for one direction of travel and are usually included
with mobilization rather than demobilization. Transportation
costs are variable and dependent on site location as well as
on applicable oversize/overweight load permits, which vary
from state to state. The total cost will depend on how many
and which state lines are crossed.
The system is designed to be ready to operate as mounted on
the trailer so mobilization costs should be primarily the cost
of travel and the time to connect the plumbing and adjust the
membranes if necessary. The startup labor cost is included
in the total labor cost component and includes relocation and
or hiring expenses.
The cost of health monitoring programs has been broken
down into two components - OSHA training, estimated at
$l,000/person and medical surveillance, estimated at
$500/person for a total cost of $l,500/person. For two
people, on-site, this would be $3,000 Depending on the
site, however, local authorities may impose specific
guidelines for monitoring programs. The stringency and
frequency of monitoring required may have significant
impact on the project cost. A conservative estimate of
$5,000 was assumed as shown in Table 4.
Labor
Labor costs may be broken down into two major categories:
salaries and living expenses. SBP estimates that the
equipment will require two on-site personnel for operation
and maintenance. Due to the extended time requirements for
major groundwater restoration projects, SBP plans for hire
local operators or relocate personnel to the site. These
actions would minimize costs associated with living
expenses. A cost of $5,000 is estimated for hiring and or
relocation.
22
-------
TABLE 4 Estimated Costs for SBP Filtration Unit
COST COMPONENT TOTAL
1. Site Preparation Costs * $85,000
2. Permitting & Regulatory Costs * $15,000
3. Equipment Costs (amortized over 7 years) $42.850
4. startup* $5,000
5. Labor $199,080
6. Consumables and Supplies
Health & Safety Gear $3,000
Maintenance Supplies $500
7. Utilities
Telephone $6,600
Electricity $2,000
Sewer/Water $2,000
8. Effluent Treatment & Disposal (Concentrate) 513,9154695,520
9. Residuals/Waste Shipping, Handling $46,000
and Transport Costs
10. Analytical Costs $60,000
11. Facility Modification, Repair & Replacement $37,150
12. Demobilization Costs * $10,000
TOTAL (WITHOUT CONCENTRATE DISPOSAL) $514,180
TOTAL (WITH CONCENTRATE DISPOSAL) $528,095-$!,209,700
* one-time costs
23
-------
Site supervision will require periodic visits from the main or
regional office to oversee the progress of the remediation.
Per diem is assumed to be $125 per day per person, but may
vary widely by location. This rate is a liberal estimate
assuming that cleanups may occur in some of the more
expensive areas of the country. Travel to and from the site
(periodic supervision) is estimated to be $800/visit. One
rental car is assumed to be obtained at a rate of $55/day.
Supervisory and administrative staff will consist of an off-
site program manager at $75/hour. The SBP filtration
system will operate 7 hours per day, 5 days per week. One
equipment operator/ supervisor at $50/hr. and one technician
at $35/hr. will be on-site 8 hr./day. The labor requirements
and rates are detailed in Table 5.
Consumables and Supplies
There are two items to consider under this cost category.
The first is health and safety gear which include hard hats,
safety glasses, respirators and cartridges, protective clothing,
gloves, safety boots, and a photoionization detector monitor,
all estimated at $l,500/person. For two people this totals
$3,000.
The second item is maintenance supplies (spare parts, oils,
greases and other lubricants, etc.) estimated at 1% of the
annual amortized capital costs or approximately $500. The
cost of membrane forming chemicals are inconsequential
(less than $200).
Utilities
Telephone charges are estimated at $500/month plus an
additional 10% for fax service or $550/month. This will
total $6,600 annually.
Electric usage is estimated by SBP to cost about $10/day or
52.000 annually. Combined sewer and water usage costs is
assumed to be about $0.05/1000 L ($0.20 per 1000 gal).
Based on the SITE demonstration results, approximately 150
gallons of water were used to flush a 4-module system.
Hence a 12-module system was assumed to use three times
as much water or about 500 gallons/day. This would cost
about $10/day or $2,000 a year as well. This does not
consider discharge of permeate, which may incur additional
cost.
TABLES. SBP Liter Requirement!vtd Rate*
Living and Travelling Expanses: 3 days/month for 12 months
Per Diem $125/day/person x 1 person x
3 days/week x 12 weeks
Rental Car $55/day x 7 days/week x
52 weeks
Travel $800/trip x 12 months
Salaries:
Program Manager - S75/hr(1) x 8 hr/day x
36 days
$4,500
$1,980
$9,600
$21,600
Operator/Supervisor -$50/hr(1) x 8 hr/day x
230 days = $92,000
Technician -$35/hr(1) x 8 hr/day x
230 days
Relocation/Hiring
Total Labor
$64,000
$5,000
$199,080
(1) Includes salary, benefits, and administration/overhead
costs but excludes profit.
Effluent Treatment and Disposal
Two process streams are produced by the filtration unit. The
permeate is considered to be essentially free of contaminants
and is assumed to meet standards appropriate for discharge
to a POTW. The concentrate is the reduced-volume portion
of the waste stream containing the enriched contaminants.
This stream would require further treatment such as
biological degradation, incineration, fuel-blending, or some
other process appropriate to the type and concentration of
contaminants.
The filtration system being evaluated is a volume reduction
technology, and as such minimizes the volume of wastewater
that would require treatment. For this demonstration, the
technology was demonstrated as a method to reduce the
volume of wood preserving waste contaminated groundwater.
Therefore, treatment of the concentrate is not part of the
demonstrated technology and it is not necessarily appropriate
to consider costing for this parameter. However, the cost for
ueating these effluents can be a substantial factor in
designing a remediation program. Based on these issues,
overall costing wiil be calculated both with and without
effluent treatment and disposal costs.
24
-------
Two concentrate disposal options are considered in this
exercise. The first, bioremediation, is a system developed by
SBP Technologies. SBP claims that their biodegradation
system provides on-site destruction of PAH contaminants.
At this time, the bioremediation system has not been tested
as a full-scale process. SBP has provided a projected cost
estimate of 10-40 cents per gallon of groundwater
contaminated with 100-2000 ppm of PAHs for its full-scale
bioremediation system.
The second disposal option for the concentrate is more
conventional and was derived from the demonstration.
Based on the characteristics of the concentrate, fuel blending
is considered a viable disposal option, resulting in a cost of
$1.50/gallon.
It is important to note that effluent treatment costs can be
very high and are dependent on specific waste and site
conditions. Cost estimates for this exercise were based on
waste and site characteristics of the demonstration.
Based on the SITE demonstration, the concentrate accounts
for 20% by volume of the contaminated groundwater
influent stream to the filtration unit. The volume of
concentrate generated each day and the range of costs for the
three different flow rates suggested by SBP are shown in me
following table for the bioremediation system and
conventional disposal:
Gallons of Waste Treated/Day
24gpm
10.060
Gallons of Concentrate
Generated/Day (assumes 20%) 2.016
Annual Treatment Costs
Eioremediation
Annual Treatment Costs
Conventional
$46,370
$185,470
12gpm 7.2gpm
5,040 3,024
1,008 605
$23,169 $13,915
$92,736
$66,660
$696.520 $347,760 $208,725
Effluent treatment and disposal costs can range from
$14,000-$700,000 depending on the flow rate through the
filtration unit, the mode of treatment, and the cost of
treatment in SBP's bioremediation system. The reader is
cautioned that SBP's bioremediation process was not
investigated here and the effectiveness and costs of this
process have not been independently verified.
Residuals/Waste Shipping. Handling and Transport Costs
Waste disposal costs including storage, transportation and
treatment costs are assumed to be the obligation of the
responsible party (or site owner), it is assumed that residual
or solid wastes generated from this process would consist
only of contaminated health and safety gear, used materials,
etc. Landtilling is the anticipated disposal method for this
material and costs were once again derived from the
demonstration test. Twenty-six 208 L (55 gal) drums of
waste were generated during the demonstration test. This
resulted in approximately four drums of solid waste
generated each day of operation. However, due to intensive
sampling activities during the demonstration, excessive solid
waste was generated. Under actual remediation conditions,
substantially less waste would be generated. It is estimated
that approximately one drum of solid waste would be
generated each day of operation. At a disposal cost of
$200/drum, the total yearly cost of disposal is estimated to
be $46,000.
Analytical Costs
Standard operating procedures do not require planned
sampling and analytical activities. Periodic spot checks may
be executed at SBP's discretion to verify that equipment is
performing properly and that cleanup criteria are being met,
but costs incurred from these actions are not assessed to the
client. The client may elect, or may be required by local
authorities, to initiate a sampling and analytical program at
their own expense.
For this cost analysis, one sample per day for 100 days at
$600/sample was assumed to be required by local authorities
for monitoring and permitting purposes. This would total
approximately $60.000.
Facility Modification Repair and Replacement Costs
Since site preparation costs were assumed to be borne by the
responsible patty (or site owner), any modification, repair,
or replacement to the site was also assumed to be done by
the responsible party (or site owner). The annual cost of
repairs and maintenance was estimated by SBP to be
$37,150.
Demobilization Costs
Site demobilization will include shutdown of the operation,
final decontamination and removal of equipment, site
cleanup and restoration, permanent storage costs, and site
security. Site demobilization costs will vary depending on
whether the treatment operation occurs at a Superfund site
or at a RCRA-corrective action site. Demobilization at the
latter type of site will require detailed closure and post-
closure plans and permits. Demobilization at a Superfund
25
-------
site does not require as extensive post-closure care; for
example, 30-year monitoring is not required. This analysis
assumed site demobilization costs are limited to the removal
of all equipment and facilities from the site. It is estimated
that demobilization would take about two weeks and consist
primarily of labor charges. Labor costs include salary and
living expenses. See "Labor Costs" for information on labor
rates. Demobilization is estimated to be $10,000.
Grading or recompaction requirements of the soil will vary
depending on the future use of the site and are assumed to
be the obligation of the responsible party (or site owner).
4.5 Results
Table 4 shows the total annual cleanup cost to range
between $514,180 and $1,209,700. This is based on me
assumption that the remediation will take one year. Most
applications for this technology will require several years, as
in pump-and-treat remedial projects. Since many of the cost
factors are one-time, the overall $/gallon cost will go down
as the length of the project increases. This is illustrated in
the hypothetical site example in the subsequent sub-section.
The total cost is also highly dependent on whether
concentrate treatment and disposal is considered as part of
SBP's technology and responsibility. Concentrate disposal
costs can vary widely, and are dependent on technical and
regulatory issues related to the waste characteristics.
Therefore, if concentrate disposal costs are considered, this
category could account for up to 60% of the total costs.
Without concentrate disposal, labor is the dominant cost,
accounting for approximately 40% of the cost. Equipment
costs represent a relatively minor component. Furthermore,
the system can be easily scaled-up by adding 12-module
units. SBP indicates that up to three 12-module units could
be operated without adding additional labor. This would
significantly reduce overall treatment costs. The smallest
cost categories appear to be those associated with startup,
and consumables and supplies. All other cost categories
appear to contribute to the total cost about equally (i.e. 5-
10%).
The costs per 1,000 gal is dependent on the flow rate, the
duration of the project, whether concentrate disposal is being
considered, and the cost of effluent treatment and disposal.
These ranges are shown below and are based on a one year
project.
With Concentration
Disposal
24 gpm 12gpm 7.2 gpm
Cost par thousand gallons of feed
$228 $456 $760
$522 $1,044 $1,739
Without Concentrate
Disposal
$222 $444 $739
In all of the above analyses, it should be remembered that
costs for 10 out of the 12 cost components were considered.
One of the cost components not included here was
permitting and regulatory expenses. Additional effluent
treatment and disposal for the permeate was assumed to be
not required. If these factors are taken into account, costs
could significantly increase.
4.6 Remediation of a Hypothetical Site
The economic analysis presented in the preceding sections
is based on costs for a one year remedial project. The
dominant application of the membrane system is expected to
be for groundwater restoration projects. Since groundwater
restoration projects can last for ten to twenty years, a
hypothetical economic analysis is presented to illustrate the
application of the twelve factors in developing a multi-year
project.
The hypothetical site contains groundwater contaminated
with wood preserving wastes (creosote and PCP) in
composition and concentrations similar to the feedwater
tested in this demonstration. The remedial plan calls for
containment of the groundwater plume, with eventual aquifer
restoration. A hypothetical model predicts that
approximately two million gallons of groundwater is
contaminated, and that 10 pore volumes of groundwater
(twenty million gallons) must be treated to restore the
aquifer. The groundwater will be extracted from me shallow
aquifer (ten to thirty feet below surface) through three wells.
The remedial design will utilize three 12-module filtration
units operating at 7.2 gpm/unit for a combined throughput of
2 1.6 gpm. Treatability testing identified that an 80% volume
reduction could be achieved, with the permeate meeting
discharge standards to me local POTW. The concentrate
from the process will be treated on-site by a bioremediation
technology similar to SBP's proposed system at a cost of 40
cents/gallon, [see Appendix B.) Based on these conditions.
and the economic assumptions previously stated, the
remedial time-frame will be ten years. Approximately
2.100.000 gallons of groundwater will be treated each year
26
-------
by the filtration unit, and 420,000 gallons of concentrate by
the bioremediation system. The total volume of groundwater
fo be treated for the ten year project is 21 million gallons.
Table 6 is a summary of the costs for each of the twelve
criteria as they relate to the conditions set forth in the
hypothetical analysis. Based on the requirements of the
hypothetical site, the overall treatment costs for the
remediation is $300/1,000 gallons. It is important to note
the overall $/gallon treatment cost is highly dependent on the
length of the remediation project. The longer the project.
the lower the $/gallon treatment cost.
27
-------
TABLE 6. Hypothetical Site Cost Analysis
Ten Year Project (1993 Dollars)
1. Site Preparation $85,000
2. Permitting and Regulatory $15,000
3. Equipment $900,000
4. Startup 55,000
5. Labor $1,990,800
6. Consumables and Supplies 535,000
7. Utilities $106,000
8. Effluent Treatment and Disposal 81,669.248
9. Residuals $460,000
10. Analytical $600,000
11. Facility Modification Repair and Replacement $371,500
12. Demobilization 310.000
$6,247,548
28
-------
APPENDIX A
PROCESS DESCRIPTION
A.1 Introduction
This section of the report presents a concise description of
the SBP Filtration Unit and its operation at the American
Creosote Works site. Factors involved in site and waste
selection are presented in this section or in the body of the
report to assist engineers and scientists in evaluating the
suitability of the process for their own needs at Superfund
and other hazardous waste sites. Results of the
demonstration, including summaries of analytical test results,
are presented in Appendix C.
A.2 Process Description
Membranes are being used increasingly for the removal of
dissolved and colloidal contaminants in wastewater streams.
Reverse osmosis (hyperfiltration) is well known for its
ability to concentrate ionic species while ultrafiltration has
found broad utility for the removal of dispersed colloidal oil,
non-settlable suspended solids, and larger organic chemical
molecules. One of the major problems these processes have
faced is the fouling or blinding of the membranes after
limited use. Various approaches have been developed in an
effort to minimize this deterrent. Cross-flow filtration, where
the contaminants are constantly flushed or washed from the
membrane surface by the feedwater stream, is one of these
approaches. The SBP unit goes further. Rather than a thin
polymeric membrane requiring careful handling to avoid
perforation, a membrane is created on a stainless steel
microfilter support by the introduction of a mixture of
carefully selected (and proprietary) chemicals. This approach
imparts special properties and allows a degree of
customization that may be difficult to achieve with
conventional membranes. The resulting "formed-in-place"
membrane can be designed to provide properties similar to
conventional hyperfiltration or ultrafiltration. as needed for
a specific application.
The filtration unit consists of porous sintered stainless steel
tubes arranged in a modular, shell-and-tube configuration.
Multi-layered inorganic and polymeric "formed-in-place"
membranes are coated at microscopic thickness on the inside
diameter of the stainless steel tubing by the recirculation of
an aqueous slurry of membrane formation chemicals. This
"formed-in-place" membrane functionally acts as a
hyperfilter. rejecting species with molecular weights as low
as 200. in addition, surface chemistry interactions between
the membrane matrix and the components in the feed play
a role in the separation process. A relatively clean stream,
called the "permeate", passes through the membrane while
a smaller portion of the feedwater, retaining those species
that do not pass through the membrane, is retained in a
stream called the "concentrate" or "reject".
For efficient operation of a membrane filtration system, it is
necessary to prevent the buildup of dissolved and particulate
species on the surface of the membrane and in the
membrane pores. The buildup of contaminants, termed
"fouling", can lead to a steady decline in the permeate flux
(flow per unit area of membrane surface), eventually causing
cessation of flow. To prevent or retard excessive fouling, the
SBP filtration unit is operated in a cross-flow mode (Figure
1) In cross-flow mode the feed stream is directed parallel to
the surface of the membrane. Material larger than the surface
29
-------
porosity is temporarily retarded on the membrane surface
and then swept clean by the cross-flow action - if the fluid
velocity is sufficient. Meanwhile, the portion of the stream
containing the smaller species passes through the membrane.
The goal of cross-flow filtration is not to trap components
within the pore structure of the membrane.
The SBP test unit used in this demonstration operates with
four modules aligned in parallel. The filtration unit is
approximately 13 feet long, 5 feet wide, and 7 feet high and
contains an estimated total membrane area of up to 300
square feet. Automatic level controls provide for unattended
operation with continuous feed to the tank. Concentrate
recycle flow also can be controlled automatically. Figure 2
provides a schematic of the filtration unit.
At the American Creosote Works site, groundwater was
pumped from a well to an aboveground storage tank where
a quiescent period of several hours allowed oil and
suspended solids to coalesce and separate. The feedwater
stream to the filtration unit was drawn from the mid-section
of the storage tank to minimize introduction of these
materials. The pump that drew material from the tank also
provided the compression for the system to operate,
approximately 750 psig.
The permeate leaving the filtration unit was sampled as
required and then discharged in accordance with permit
requirements. The concentrate was collected in a smaller
tank until the desired volume was accumulated. It is then
recycled as feed until the desired final concentration and
volume are achieved. This mode of operation was selected
for the demonstration in anticipation of a companion study
of a proprietary biodegradation process for the concentrate.
Alternate operating modes can be used to achieve other
goals, depending on disposal plans and options for the
permeate and the concentrate.
Influent
Permeate
o
°o T o Concentrate
O Species > 200 Molecular Weight
0 Species < 200 Molecular Weight
Figure 1. Cross-Flow Filtration
Groundwater
V
1
F«ed
Membrane
~ Filtration -O
Feed Tank
*
i
*» Membrane
Filtration Unit
Permeate I*
Disposal *
^ Cotic,enJtr.ate. Recycle* i
Concentrate
^ Storage
Tank
r
Sampling Points
Figure 2. Schematic of SBP Filtration System
30
-------
APPENDIXB
VENDORCLAIMSANDCASESTUDIES
Note: Information contained in this appendix was provided by SBP Technologies, Inc. and
has not been independently verified by the SITE Program.
B. 1 Introduction - HyperfiltrationSystem
SBP's hyperfiltration system, which consists of porous
stainless steel tubes internally coated with specially
formulated chemical membranes, has been demonstrated to
successfully treat water contaminated with a number of
hazardous or toxic materials. In this system, contaminated
ground and surface waters are pumped through the filtration
system tubes and contaminants are collected inside the tube
membrane while "clean" water permeates the membrane and
tubes. The system has been shown to be highly versatile
and able to effectively remove a variety of materials from
contaminated waste streams, including petroleum
hydrocarbons, benzene, toluene, ethylbenzene. xylene.
chlorinated dioxins. chlorinated furans, and heavy metals.
This extent of versatility is provided largely by the
application of several types of chemical membranes with
distinct permeability and ion exchange capabilities.
As discussed in this Applications Analysis Report, SBP used
this hyperfiltration technology in a pilot-scale field study,
performed in conjunction with the U.S. EPA Superfund
Innovative Technology Evaluation (SITE) Program. At the
American Creosote Works (ACW) site in Pensacola, Florida.
groundwater has been encountered with significant wood
preserving waste contamination, of which a significant
percentage is high molecular weight carcinogenic
polynuclear aromatic hydrocarbons (PAHs) and
pentachlorophenol (PCP), typically associated with the wood
treatment industry.
In this field study, one type of chemical membrane was used
to coat the porous stainless steel tubing, with an aim to
provide the optimal separation efficiencies for the higher
molecular weight contaminants. These are generally
;egarded to be most "hazardous" molecules and are generally
more resistant to degradation in the environment. The
results confirmed that this membrane system was very
effective in removing >95% (w/v) of the high molecular
weight polynudear aromatic hydrocarbon (PAH)
contaminants, the most carcinogenic components, during the
monitored demonstration run. However, on the average,
approximately 20% of the lower molecular weight phenolic
contaminants were removed by this membrane type. SBP
feels that this percentage can be improved by adjusting
membranes and flows in the field. The latitude to tinker
with the system was not available during the formal
demonstration period.
In the ACW study, the relatively heavy concentrations of
contaminants in the feed material for the hyperfiltration unit
precluded effective use of other "tighter" types of
membranes as the first pass barrier due to the potential for
fouiing. Optimally, a combination system employing the
initial membrane used here to remove high molecular weight
contaminants, followed by a "tighter" membrane to remove
lower weight phenoiics from the permeate of the first
membrane would have been more likely to provide the full
spectrum of contaminant removal desired.
31
-------
8.2 Results BTEX/Petroleum Hydrocarbon
Hyperfiltration
A. BTEX/Gasoline Contaminated Waste Stream
Other waste streams, highly contaminated with lower
molecular weight molecules, have been successfully
hyperfiltered and concentrated using alternate chemical
membrane types than that used in the ACW field site
demonstration. One example has been the hyperfiltration of
waste water from certain oil refining operations containing
significant amounts of benzene, toluene, ethylbenzene. and
xylenes (BTEX), as well as other petroleum hydrocarbons.
A summary of the hyperfiltration results of this treatment is
as follows:
Contaminant Original Feed Sample
Permeate Sample % Removal
Benzene
Toluene
Ethyl-benzene
Xylenes
TPH
2200 ppb
7640 ppb
2590 ppb
12200 ppb
483 ppm
34 ppb
92 ppb
15 ppb
100 ppb
3.5 ppm
98.5%
98.9%
99.4%
99.2%
99.3%
B. Contaminated Landfill Liquids
In a separate study, condensate from a methane-recovery
operation at a municipal landfill was treated for the removal
and concentration of a large spectrum of contaminants,
including naphthalene, heavy metals, and BTEX. The results
of this are:
Contaminant Original Feed Sample
Permeate Sample % Removal
Toluene
Ethyl-benzene
Xylenes
Naphthalene
177 ppm
268 ppm
561 ppm
90.4 ppm
<5 ppm
<5 ppm
<10 ppm
<10 ppm
>97.2%
>98.1%
>98.2%
>89.0%
'All permeate readings were below the detectable limits for the analysis method
used in this study.
B.3 Conclusions - Hyperfiltration System
These results demonstrate the capacity and versatility of the
hyperfiltration system in treating a variety of waste streams
and achieving effective volume reduction in removal of
contamination from groundwater. municipal landfill
leachates, or contaminated petroleum waste streams. The
vaiue of this technology can be further enhanced by coupling
it with a biodegradation process. This can be achieved by
usmg the hyperfiltration concentrate as a biorcactor feed
stream, as well as by using the hyperfiltration system to
polish bioreactor effluent to yield two streams: one, a clean
stream suitable for discharge; and the other, a polished
concentrate to feed to the bioreactor. This creates a closed
loop for targeted contaminants, and provides for an efficient
continuous flow remediation design.
B.4 Introduction - Bioremediation System
In addition to the application of hyperfiltration technology to
the remediation of creosotecontaminated groundwater from
the American Creosote Works (ACW) site, effective
biodegradation of creosote and pentachlorophenol has also
been achieved at this site by SBP using specially selected,
non-engineered microorganisms in a pilot-scale bioreactor
system. The combination of these two systems,
hyperfiltration and bioremediation. provides a novel and
reliable means to first concentrate the waste feed to the
bioreactor to an optimal level for efficient bioremediation
activity, as well as to provide for a final polishing step using
hyperfiltration of bioreactor effluent.
For this study on the ACW site, a bi-phasic bioreactor
design was utilized, operating in a semi-continuous flow
process, having a hydraulic retention time of four days.
Groundwater, with contaminant concentrations as high as
7.000 ppm creosote, was ueated on-site. This
demonstration achieved a removal efficiency of greater than
99% for total polynuclear aromatic hydrocarbons (PAHs).
This includes a removal rate of 98% for the most
recalcitrant, and most hazardous fraction of the PAHs and
88% for PCP. The field test proved that SBP's
biotechnology application for hazardous waste remediation
can be effective at an actual waste site. SBP is ready to
apply this bioremediation approach for on-site treatment of
PCP and PAH-contaminated soil, sludge and water.
B.5 PAH and PCP Contamination and
Bioremediation
PAHs are a widespread contaminant of soil and groundwater
typical of creosote wood treating facilities, manufactured gas
plants, refineries and related industries. Bioremediation has
been attempted for PAH constituents in several studies and
field applications, but until now. biodegradation using
indigenous bacterial strains has been able to achieve only
50% to 75% removal dFAHs. The untreated portion is
generally comprised of the recalcitrant high molecular
weight (HMW) PAHs which are those compounds with 4. 5
or 6 fused rings and are the PAH components which are
known or suspected carcinogens (see Table 7). Similarly.
32
-------
PCP, a common wood preservative, has proven difficult to
biodegrade under field conditions.
TABLE 7. Classes and Characteristics of PAHs
Low Molecular Weight PAHs - relatively non-hazardous,
relatively easy to degrade.
naphthalene
2-methylnaphthalene
1-methylnaphthalene
biphenyl
2.6-dimethylnaphthalene
2.3-dimethylnaphthalene
Medium Molecular Weight PAHs - some potentially
hazardous to human health, more complex but still
biodegradable by many bioremediation systems.
acenaphthylene
anthacene
fluorene
phenanthrene
2-methylanthmcene
anthmquinone
High Molecular Weight PAHs - several carcinogens, very
slow rates of biodegradation without specialized microbes.
fluoranthene
pyrene
benzo(b)fluorene
chtysene
benzo(a)pyrene
benzo(a)anthmcene
bento(b)fluomnthene
benzo(k)fluomnthene
indeno(l,2.3-c,d)pyrene
Since 1987, SBP, in collaboration with USEPA scientists at
the Gulf Breeze (Florida) Environmental Research
Laboratory (GBERL), has isolated and identified several
strains of naturally occurring soil bacteria capable of
mediating PAH and PCP degradation at rates in excess of
those achieved by undifferentiated communities of
indigenous microbes. The strains are identified as:
CRE 1-13: low and medium weight PAH degraders
comprised of an assemblage of 13 Pseudomonads.
EPA 505: a strain of Pseudomonas paucimobilis capable
of high rate degradation of HMW PAH constituents.
SR3: a strain of Pseudomonas sp. which degrades PCP.
All organisms have been shown to mineralize their target
contaminants. Additionally, EPA 505 has been patented for
use in the degradation of high molecular weight PAH.
Through a Cooperative Research and Development
Agreement with EPA, SBP has the exclusive license to
market the PAH degraders along with rights to certain other
environmental biotechnology developed at GBERL.
The SBP bioremediation process was tested on groundwater
from the ACW Superfund Site in Pensacola, Florida. The
ACW site was an active wood treatment facility from 1902
to 1981. Both creosote and PCP were used as wood
preserving agents during the site's operation. Waste liquids
from the process were placed in unlined surface
impoundments on-site. These impoundments often
overflowed into drainage ditches which discharged into local
waterways. In addition, wastes have migrated into the
shallow aquifer, contaminating both soil and groundwater.
The ACW Superfund site has large volumes of shallow
groundwater contaminated by creosote and PCP. In order to
prove the capability of the SBP organisms to degrade these
contaminants under field conditions, a highly contaminated
groundwater was chosen as the test matrix.
Groundwater was pumped from the aquifer via an existing
monitoring well. The extracted groundwater was stored in
an equalization tank prior to the test From this tank, the
contaminated feed was pumped to the two-stage bioreactor
treatment system (see Figure 3). Each bioreactor had a
hydraulic capacity of 200 gallons and was designed to
provide mixing and up-lift type aeration.
The bioreactors were operated sequentially, i.e., the
contaminated water was transferred to Bioreactor 1 (BR1) at
a pre-set flow rate of four days. After four days, when BR1
was full, the water was allowed to overflow into Bioreactor
2 (BR2). Laboratory grown concentrates of CRE 1-13
(specialized degraders for the low and medium weight
PAHs) were added to BR1, along with nutrients and sparged
air, and the tank was mixed. Similarly, BR2 was inoculated
with EPA 505 (HMW PAH-degradmg strain) and SR3 (PCP
degrader) during its eight days of operation. Treated flow
from BR2 was held in a tank for testing; after testing, the
water was discharged to the city sanitary sewer.
33
-------
Contaminated
Groundwater
CRE 1-13
1
r
Bioreactor
No. 1
Nutrients &
Air
Nutrients &
Air
Discharge to City
Sanitary Sewer
Figure 3. Simplified Process Flow for SBP
Technologies Inc.'s Bioreactor System
During operation of the bioreactors, samples were collected
for the analysis of key operating parameters, such as
dissolved oxygen, nutrient levels, total organic carbon and
suspended solids. Microbial analysis was performed to
assess the cell concentration of the specialized bacteria being
added. All cultures were prepared in advance and added to
the bioreactors to obtain a final concentration of
approximately 1 X 106cfu/mL. Additional samples were
collected to measure the contaminant concentration across
the bioreactor, as well as in rhe various portions of the
treatment system, in order to calculate a mass balance.
B.6 Bioremediation Results
The overall PAH and PCP degradation performance of
SBP's treatment system is shown below.
TABLE 8. Summary of Bioremediation Results of PAH and PCP Removal
Contaminant Influent
(mg/L)
Low Molecular Weight PAHs 31
Med Molecular Weight PAHs 539
High Molecular Weight PAHs 368
Pentachlorophenol 256
Effluent
(mg/L)
8.1
1.6
52
31
% Removal
<99
>98
98
88
These results represent a significant advancement in PAH
bioremediation. Not only has the total PAH been reduced to
<1% of its original concentrations, the HMW PAH. a class
of compounds which are typically not removed in biological
remediation systems, have been reduced by 98-plus percent.
This removal has the additional significant characteristic of
having been mediated by an organism specially and
specifically isolated, cultured and introduced into the
bioremediation system to remove this class of compounds,
and this has been accomplished under typical field
remediation conditions.
To further validate the treatment technology, the
contaminated groundwater was subjected to tests for toxicity
and teratogenicity before and after treatment (sampled before
carbon treatment). As determined by McrotoxTM, embryonic
Menidia beryllina, Mysydopsis bahia, and Ceriodaphnia
dubia bioassays, these indicators of potential threat to human
health and the environment were significantly reduced.
These data show that the treatment system was effective in
removing the hazardous properties of the waste material,
while simultaneously demonstrating that no metabolic by-
products or toxic intermediates were created by the microbial
biotransformation of the waste constituents.
A mass balance was performed by comparing the total
influent loading of PAHs to the residual PAHs left in the
treatment system at shutdown. The HMW PAHs were found
to be 80% removed (20% remained in the residual). In a
scaled-up system with higher volume of waste water mated.
the removal efficiently at steady state would approach the
percent removal from influent to effluent (98%).
B. 7 Technology Application
SBP's approach to bioremediation of hazardous waste sites
is a "multi-phase" strategy, meaning that the technology is
adaptable to the treatment of soil, sludges, leachates,
groundwater and surface water. By the multi-phase
approach, the waste matrix is modified and managed :o
support the greatest level of specialized organisms survival
and highest biodegradation rates. Examples are given below.
Bioremediation is applicable to a wide range of organic
contamination. SBP has focused on research, development
and field implementation of biotechnology-based approaches
to some of the more difficult hazardous waste constituents.
in particular wood preserving wastes and solvent
contamination. SBP has bioremediation solutions for:
PAHs (e.g., creosote, coal tar)
Chlorinated Aliphatic (e.g.. TCE)
34
-------
Pentachlorophenol
Petroleum Hydrocarbons
Treatment of contaminated liquids such as water, leachate,
filtrate, groundwater, storm water, surface water and
industrial process waste water can be accomplished by
several of SBP's technologies. Certain waste streams can be
concentrated by our hyperfiltration units; the permeate is
clean water and the "concentrate" contains the reduced
volume of the pollutants. These concentrated contaminants
can often be bioremediated. thus minimizing the waste
stream. Other liquids may be treated directly, either by
biological processes, or in the case of volatiles, air stripping
with biotreatment of the pollutants in a gas phase bioreactor,
or "biofilter".
SBP has developed several approaches for the handling of
contaminated soil. Solid phase systems are used when
biostimulation of indigenous bacteria is appropriate. Slurry
phase reactors, either in-vessel or in situ are used for soils
or sludges requiring better control of microbial systems. A
multi-phase approach combining soil washing and
hyperfiltration to reduce volume and bioreactor treatment of
the washwater is appropriate for heavily contaminated
wastes.
35
-------
APPENDIX C
SITE DEMONSTRATION RESULTS
C.I Introduction
The goal of this demonstration project was to study the
effectiveness of the SBP formed-in-place hypefiltration
membrane unit, operating in a cross-flow mode, for the
concentration of PAHs (and PCP) from contaminated
groundwater found at a wood treating site. The original plans
called for a companion study of a proprietary biodegradation
process for the concentrate: however, a decision was made
during this study not to carry out that portion of the study.
Based on available information, including a Remedial
Investigation/Feasibility Study (RI/FS), the American
Creosote Works site in Pensacola, Florida was selected for
the investigation. The site was included on the National
Priorities List on the basis of the RI/FS study which
suggested that the groundwater under the site was heavily
contaminated with both PAHs and PCP.
The American Creosote Works site had been used for wood
treatment from 1902 to 1981. Creosote was the preservative
used until the 1970's when a shift was made to
pentachlorophenol in a light oil. Over the years, wood
impregnation was carried out in open troughs, resulting in
spills and drippage which seeped into the ground. Figure 4
presents the general layout of the facility and indicates the
location of the well that was drilled to assess the suitability
of the site for the SITE demonstration project. This well was
selected as the source of groundwater for this demonstration.
The well yielded sufficient groundwater voiume and flow but
the output was contaminated with free product. Field COD
tests were used to determine that five-fold dilution of the
groundwater with city water was necessary to meet the 100 -
500 mg/L COD input guideline for feedwater to the pilot
filtration unit. Approximately 700 gallons of the groundwater
was pumped from the well on alternate days. The
groundwater was allowed to settle for several hours, and the
aqueous phase pumped to a separate tank. The contaminated
aqueous phase was diluted with 2,800 gallons of carbon-
treated city water to bring the contaminated level of the feed
in the desired range of 100 to 500 mg/L COD.
Approximately 1,000 gallons of this diluted stream was used
as the feedwater to the filtration unit per day. The average
characteristics of this feed stream are shown in Table 9, and
are based on composite samples taken on each day over the
six days of the demonstration.
Figure 4. American Creosote Works Site
36
-------
TABLE 9. Average Characteristics of Feed Stream to the SBP Filtration Unit
Analyte
Average
IDS (ppm)
TSS (ppm)
TOC (ppm)
COO (ppm)
Oil/Grease (ppm)
Semivolatiles (PPD)
Phenol
2-Melhylphenol
4-Methylphenol
2,4-Qimethylphenol
Pentachlorophenol
Benzole Acid
Naphthalene
2-Mettiylnapttialene
Acenaphthylene
Acenaphthene
Dibenzofuran
fluorene
Phenanthrene
Anthracene
fluoranttwne
Pyrene
3enzo(a)Anttiracane
Chrysena
8enzo(b)Fluoranthene
8enzo(k)Fluoranttiene
8enzo(a)Pyren9
237
34
121
379
199
4,900
2,308
6.917
1,817
(2,425)
(1,421)
12,867
4.525
(138)
6.842
4,875
5.925
17.083
1,983
7,008
4,700
1,235
1.127
(460)
(428)
(312)
( ) estimated value
To achieve the desired volumes and concentrations, the
feedwater was introduced during the first two hours
(approximately) of each day's run. For the remainder of each
day's run, the reject (concentrate) was recycled, becoming
the feed, while the permeate was continuously removed and
discharged to the POTW after samples were composited for
analysis. Each day's run was terminated when the
flowmeters indicated that the desired 800 gallons of
permeate had been discharged, leaving approximately 200
gallons of concentrate.
Samples were analyzed for oil and grease, dissolved and
suspended solids, volatile organics, TOC. COD, and
dioxins/furans in addition to the list of designated
semivolatile organics used in evaluating the developer's
claims.
C2 Field Activities
SBP personnel were responsible for preparing the membrane,
operating the system over the test period (six days), and
washing of the unit on alternate days. Separation of the oil
and other readily separable material and dilution of the
groundwater with city water were field decisions that were
agreed to by SBP and EPA to meet the operational
requirements of the filtration unit. EPA's contractor
personnel monitored flow rates and sampled feed, permeate,
concentrate, and washwater while the system was operating.
While some leaks were encountered during the shakedown
of the filtration unit, no breakdowns occurred during the six
days of testing. The flux (transport of liquid across the
membrane) did have a tendency to decrease during each day
of operation, but this was accommodated by manually
increasing the pressure.
C.3 Test Procedures
As noted earlier, the system was operated by introducing
approximately 1,900 gallons of the diluted feedwater (about
1 volume of groundwater to 4 volumes of city water) over
a two hour period at a rate of about 8 gpm. At that time,
recycle of the concentrate was initiated and continued until
approximately 800 gallons of permeate was generated and
approximately 200 gallons of concentrate was collected.
Based on operational parameters (flux, pressure), the
developer determined that washing of the unit was necessary
every other day. At the end of the second day, the fourth
day, and the sixth day approximately 200 gallons of city
water, to which cleaning chemicals had been added, was
flushed through the system and collected. This material was
also analyzed.
Grab samples of the feed stream were collected every 1.5
minutes during the initial two-hour single pass phase, while
permeate grab samples were collected every 45 minutes over
the whole run. Laboratory samples were prepared by
compositing the grab samples on a flow proportional basis.
After the initial single pass, the concentrate was recycled for
approximately four hours in each test and one composite
sample was taken at the end of each run. All samples were
transferred to bottles, inhibited or preserved as called for by
the individual test methods, labelled, sealed, and shipped in
ice-tilled coolers to off-site laboratories by overnight
express.
Instantaneous flow and accumulated volumes of feed and
permeate were measured automatically using calibrated
flowmeters. Volume of the final concentrate was determined
by the difference between the feed and permeate volumes.
The temperature and pH in the three streams were measured
in the field and recorded to assure that there was no gross
change in characteristics that could affect filtration
-------
effectiveness. Sampling points are indicated on the schematic
of the system, shown in Figure 2. The sampling schedule,
analytical protocols and results, and QA/QC protocols are
described fully in the Technology Evaluation Report. The
ongoing QA program allowed for the collection and
reporting of high quality data.
At the end of the sixth day of operation, after all the
required samples had been taken, the process was allowed to
continue for several hours, further concentrating the
contaminants. Additional samples of the permeate were taken
about every 25 gallons to observe whether there was a fall-
off in contaminant rejection rate.
C4 Results
The following results are all based on the composite
analytical results and field data obtained on each day. The
Technology Evaluation Report presents the complete data for
grab and composite samples taken each day of feed,
permeate, reject, and washwater.
Operation of Unit
The filtration unit operated in a batch mode for six hours
each day, for six days, and processed approximately 1,000
gallons of feed per day. Over the six day test period,
permeate flux was a relatively constant 0.0085
gak'ons/min/ft2 (coefficient of variation < 10%). Based on
a total membrane area of 300 ft2 for the system, the
permeate flow rate for the four-module filtration unit
averaged 2.6 gpm.
The unit was cleaned every two days with approximately
200 gallons of city water and membrane cleaning materials.
Over the two day period, the surface of the membrane
gradually fouled, requiring an increase in feed pressure in
order to maintain a constant permeate flux. The cleaning at
the end of each two-day period was sufficient to restore the
original flux. Figure 5 depicts the pressure adjustment over
each two day period necessary to maintain the constant flux
(Figure 6).
MO*
#ws *« MWI
i (min)
Figure 5, feed Pressure vs. Run Time
|3
K 3-.«* f~
« «G7 f*
S ,ao«>.
M '
2 \1QOS f»
A. «J*4 i-
a **
a 31
TilH«<
Figure 6. Flux vs. Run Time
Semivolatile Contaminant Analysis
Contaminant Reduction
It was agreed between SBP and EP.4 that a selected list of
semivolatile organic compounds would be used to assess the
effectiveness of ihe Filtration Unit. The analytes consisted
of all quantifiable semivolatile compounds (Method 8270)
detected in the feed.
Rejection efficiency was defined as the change in total
concentration for these contaminants between the feed and
the permeate:
38
-------
% Rejection = 10Q-Cr X
Q
where
C, = total concentration of contaminants in feed
Cp = total concentration of contaminants in permeate
On the basis of composite samples, rejection for the total
designated contaminants averaged 74% over the six days, as
shown in Table 10.
Analysis of the data reveals that the system is very effective
for the rejection of polynuclear aromatic hydrocarbons and
much less effective for phenols. Separated in this fashion,
rejection for the PAHs averaged 92% over the six days
while rejection for the phenols averaged 18%.
TABLE 10. Overall Semivolatile Rejection for the SBP Filtration Unit
Ju-
I 1.4
M
11*
190
13« 13* 170
Motocafcr Weigfct
Figure 7. Molecular Weight vs. Order of
Magnitude Reduction (ORD)
Mass Balance
Day Feed Permeate Concentrate
(ppm) (ppm) (ppm)
Rejection
1
2
3
4
5
6
104
91
92
104
85
60
18
24
26
22
23
24
206
585
248
242
199
538
83
74
72
79
73
60
A more accurate means of quantifying and graphically
representing rejection is to calculate the reductions on a
logarithmic basis. For exatnple. attempting to graph
differences between 90% and 99% rejections does not fully
depict the fact that a ten-fold reduction has occurred. In
order to accurately represent this process, it is necessary to
calculate the order of magnitude of rejection (ORD) as the
log value of the ratio of the contaminants concentration in
the feed to the concentration in the permeate. The equation
is written as:
ORD = Log OCp)
Therefore, an ORD of 2.0 means that a 100 fold decrease in
contamination has occurred in the permeate relative to the
feed. An ORD of 1.0 means a 10-fold decrease has
occurred.
For the semivolatile constituents, it appears that rejection
follows the molecular weight of the chemical. Figure 7
presents the average ORD over the six days versus the
molecular weight of the individual compounds.
Combining the masses of pollutants in the permeate and the
concentrate on a daily basis did not provide a good material
balance, relative to the feed. Only when the material in the
washwater was also included was all the material accounted
for. Based on the volume of washwater used in each
washing operation, approximately 200 gallons, about 8% of
the masses of the designated pollutants are retained on the
membrane or in the liquid in the system. Table 11 provides
a summary of the contribution of the different streams for
each two-day period between wash operations. The relative
distribution of pollutants in the washwater was very similar
to that in the concentrate, with PAHs far exceeding the
phenols. However, the concentration of pollutants in the
washwater was similar to the feedwater.
TABLE 11. Mass Contribution of Total Semivolatiles in all Streams (2 day
totals)
Days Feed Perm Cone Wash Total Recovery
(Influent) Effluent
gms gms gms gms gms %
1 &2
3&4
5&6
777
778
581
140
159
151
566
320
i 11
46
84
32
742
563
710
95
72
122
6 day recovery = 94%
Extended Operation
After the system yielded the desired 200 gallons of
concentrate on the sixth (last day) of the test and all
necessary samples had been taken, operation of the system
was continued with further recycle of the concentrate as long
39
-------
as possible to observe the behavior of the unit (i.e., the rate
of fouling and the quality of the permeate). The extended
operation resulted in only thirty seven gallons of concentrate
remaining, representing a 97% volume reduction. However,
during this time the rejection efficiency decreased, as
expected, as concentration continued (Table 12).
TABLE 12 Behavior on Extended Fiibation
Additional Gallons of
Permeate Produced
25
50
75
100
150
Semivolatile Rejection %
(calculated from initial Feed)
47.5
48.5
60.0
32.3
21.7
Conventional Parameters
In addition to the designated semivolatile pollutants, the
removal of several conventional parameters from the
feedwater was also evaluated. These included total dissolved
solids (TDS), total suspended solids (TSS), chemical oxygen
demand (COD), total organic carbon (TOC), and oil and
grease (O&G). Comparison of feed and permeate confirm
that the membrane is capable of removing larger molecules
such as oil and suspended solids, but is not nearly as
efficient in the removal of dissolved material (TDS) or
otherwise-unidentified organic species (COD and TOC).
Such results, summarized in Table 3, suggest that the
membrane is operating predominantly as a hyperfiltration
membrane. In addition, considerable concentrations of
organics remain in the permeate even though the PAHs are
efficiently removed. For example, the ratio of
semivolatiles/COD decreases significantly, from about 0.2 in
the feedwater to about 0.07 in the permeate, demonstrating
that semivolatiles are not the major contributor to the COD,
and that significant unidentified, smaller molecular weight
compounds can pass through the membrane.
Polvchlorinated Dibenzo-p-Dioxins/Dibenzofurans
Polychlorinated dioxins (PCDDs) and furans (PCDFs) are
often encountered in the manufacture of pentachlorophenol
and can remain with the commercial product. To investigate
this matter, selected samples of the three streams taken on
the first, second, and sixth day of the demonstration were
scanned for the various dioxins and furans using high
resolution GC coupled with low resolution MS. A number of
the more highly chlorinated dioxin and furan species were
found in the feed water and in the reject at significantly
higher concentrations, but analyses of the permeate indicated
efficient removal of these pollutants. The 2,3,7,8-TCDD
isomer was not found above the detection limit in any
sample of feed, permeate, or concentrate. The 2,3,7,8-TCDF
isomer was found in only one sample of feed and one
sample of concentrate, in both cases the value was <0.5 ng/L
(ppt). The major dioxins and furans were the octa species.
These results are consistent with rejection by molecular
weight or oil solubility, but not by number of rings.
4fl
-------
TABLE 13. Qioxins/furans in Process Streams
Dayl
Feed Perm. Cone. Removal
(ng/L) (ng/L) (ng/L) %
Day
2378 TCCD
12378PeCDD
123478 HxCDD
123678 HxCDD
123789 HxCDD
1 234678 HpCDD
OCDD
2378 TCDF
12378 PeCDF
23478 PeCDF
123478 HxCDF
123678 HxCDF
234678 HxCDF
123789 HxCDF
1234678 HpCDF
1234789 HpCDF
OCDF
4 »
1
4 »
53.0
74.6
1980 1.6
14670 38.9
«
f *
4 *
11.2
3.2
8.5
.
346
28.3
1030 3.3
,
.
277.7
13.3
3836
42365
.21
.
.
52
8.7
30.4
.
1066
76
2596
99.9
99.7
99.7
. An '.'indicatesttieisomer was absent ortwlowdetection IJmitsinstream.
Day3
Feed Pwm. Cone. Removal
(ng/L) (ng/L) (ng/L) %
2378 TCDD
12378 HxCDD . .
123478 HxCDD 2.4 '
123678 HxCDD 47.7 .
123789 HxCDD 6.7
1234678 HpCOO 1460
OCDD 13250 7 . 9
2378 TCDF .37
12378 PeCDF . .
23478 PeCDF
123478 HxCDF 8.1
123678 HxCDF .
234678 HxCDF
123789 HxCDF .
1234678 HpCDF 300
1234789 HpCDF .
OCDF 224
116
9.9
3630
34135 99.9
28.4
4.2
17.0
689
40.1
1223
An '' indicates the isomer was absent or below detection limits in stream.
Feed
(ng/L)
2378 TCDO
12378PCDD
123478 HxCDD 1.9
123678 HxCDD 30.6
123789 HxCDD 4.4
1234678 HpCOO 1370
OCDD 9200
2378 TCDF .39
12378 PeCDF
23478 PeCDF .
123478 HxCDF 5.1
123678 HxCDF 1.5
234678 HxCDF 5.1
123789 HxCDF
1234678 HpCDF 1 9 6
1 234789 HpCOF 14.1
OCDF 473
Perm.
(ng/L)
,
4
.
*
.
.36
8.8
.
.
4
4
4
4
t>
.
t
.50
Cone.
(ng/L)
*
8.1
334
27.6
8950
90400
1.5
.
1.7
111.7
34.2
42.6
,
2055
126.2
5235
Removal
99.97
99.90
99.89
. An V indicates the isomer was absent or bebw detection limits in stream.
Volatile Organics
Analyses for volatile organics (VOCs) were carried out
during the runs on days 1, 3, and 6 because the developer
was somewhat concerned that the high pressures used in the
system might force volatiles through the membrane into the
permeate. All VOC concentrations were low in the
feedwater; the same species were also found in the permeate
and the concentrate but at lower concentrations. The
principal VOC was acetone, but the expected BTEX species
were also present.
TABLE 14. Volatiles in procen Streams
Feed
\tgfl.
ng/L
Mettwtene Cfitonde
Acetone
Caiton Oisuifide
2-Butanone
Benzene
Toluene
Eihvt Benzene
Styrene
Xylenes
*
2
32
16
20
12
18
43
t
<5
31
7
16
(7)
7
26
*
<5
32
<5
<5
<5
<5
------- |