United States
           Environmental Protection
           Agency
             Research and
             Development
             (RD681)
IEPA/540/A5-90/007
October 1991
&EPA
E. I. DuPont De Nemours &
Company/Oberlin
Filter Company
Microfiltration Technology

Applications Analysis Report
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                 SUPERFUND INNOVATIVE
                 TECHNOLOGY EVALUATION

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                                                 EPA/540/A5-90/007
                                                       October 1991
DuPont/Oberlin Microfiltration Technology
        Applications Analysis Report
     Risk Reduction Engineering Laboratory
       Office of Research and Development
      U.S. Environmental Protection Agency
            Cincinnati, Ohio 45268
                                           Printed on Recycled Paper

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                                                Notice
    The information in this document has been prepared for the U.S. Environmental Protection Agency's (EPA) Superfund
Innovative Technology Evaluation (SITE) program under Contract No. 68-CO-0047.  This document has been subjected to
the Agency's peer and administrative reviews 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.

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                                              Foreword
    The Superfund Innovative Technology Evaluation (SITE) program was authorized in the 1986 Superfund Amend-
ments and Reauthorization Act (SARA). The program is a joint effort between EPA's  Office of Research  and
Development (ORD) and Office of Solid Waste and Emergency Response (OS WER). 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 which are
designed to provide engineering and cost data on selected technologies.

    This project is a field demonstration under the SITE  program and is designed to evaluate the DuPont/Oberlin
microfiltration technology. The technology demonstration  took place at a former zinc  smelting facility in Palmerton,
Pennsylvania.  The demonstration effort was directed to obtain  information on  the performance  and cost of the
technology and to assess its use at this and other uncontrolled hazardous waste sites.  Documentation consists of two
reports:   (1) a Technology Evaluation Report that describes the field activities and laboratory results; and (2)  this
Applications Analysis Report that provides an interpretation of the data and discusses the potential applicability of the
technology.

    A limited  number of copies of this report will be available at no charge from EPA's Center for Environmental
Research Information,  26 West Martin Luther King Drive, Cincinnati, Ohio 45268.  Requests should include the EPA
document number  found  on the  report's cover.  When the limited supply is  exhausted, additional copies can be
purchased from the National Technical Information Service, Ravensworth Building,  Springfield, Virginia 22161, (703)
487-4600. Reference copies will be available at EPA libraries in the Hazardous Waste Collection.  You can also call
the SITE Clearinghouse  hotline at (800) 424-9346  or (202) 382-3000  in Washington, D.C., to  inquire about the
availability of other reports.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory

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                                                   Abstract
    This report evaluates the DuPont/Oberlin microfiltration technology's ability to remove metals (present in soluble or
insoluble form) and particulates from liquid wastes while producing a dry  filter cake and a filtrate that meet applicable
disposal requirements.  This report also presents economic  data from the  Superfund Innovative Technology Evaluation
(SITE) demonstration and, as available, three case studies.
    The  DuPont/Oberlin microfiltration technology combines  Oberlin's automatic pressure  filter with DuPont's  new
microporous Tyvek® filter media. It is designed to remove particles that are 0.1 micron in diameter, or larger, from liquid
wastes, such as contaminated groundwater.  Groundwater with dissolved metals must first be treated to convert the dissolved
metals into an insoluble form prior to microfiltration.
    The DuPont/Oberlin microfiltration technology demonstration was conducted under the SITE program at the Palmerton
Zinc Superfund site in Palmerton;  Pennsylvania, in April and May 1990.  During  the demonstration, the microfiltration
system achieved zinc and total suspended solids (TSS) removal efficiencies of about 99.95 percent, and a filter cake solids
content of 41  percent.  The filter cake contained no free liquids, and a composite sample from all the demonstration runs
passed both the extraction procedure toxicity test and the toxicity characteristic leaching procedure (TCLP) test. The filtrate
met applicable National Pollutant Discharge Elimination System permit limits for metals and TSS but not for pH; the filtrate
pH was typically  11.5 while the upper pH limit is 9.
    The results from three case studies are also summarized in this report. All three facilities treated process wastewaters
containing metals and TSS ranging from several parts per million to several  percent.  The filtrates at all three facilities met
their respective discharge limits. Filter cake at one facility is a mixed waste and is further stabilized and solidified with
cement prior to land disposal. At another facility, filter cake did not pass the TCLP test and is considered a hazardous waste.
No filter cake information was available from the third facility.

    Possible sites for applying this technology include Superfund and other hazardous waste sites that have groundwater and
other liquid wastes contaminated primarily  with metals and particulates. Sources of metal-bearing wastes include electro-
plating and  metal finishing facilities, electronic component manufacturers, aluminum  and other metal forming facilities, and
uranium processing facilities. Economic data indicate that the capital costs for only the microfiltration  unit and ancillary
equipment are $48,000 for a 2.4-square foot unit and about $232,000 for a 36-square  foot unit.  Annual operation and main-
tenance (O&M) costs (including analytical, labor, and disposal costs) are estimated to be about $213,000 for the smaller unit
and $549,100 for the larger unit, with corresponding annual throughputs of 525,600 gallons and  7,884,000 gallons.
                                                          IV

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                                                  Contents
                                                                                                         Page

Foreword	iii
Abstract	iv
Figures  	vii
Tables   	vii
Acknowledgements	viii

1.      Executive Summary	1

            Introduction	1
            Overview of the SITE Demonstration	1
            Results from the SITE Demonstration	,	1
            Results from the Case Studies	2
            Waste Applicability	2
            Economics	2

2.      Introduction	3

            Purpose, History, and Goals of the SITE Program	3
            Documentation of the SITE Demonstration Results	3
            Purpose of the Applications Analysis Report	3
            Technology Description	4
            Key Contacts	8

3.      Technology Applications Analysis	9

            Effectiveness of the DuPont/Oberlin Technology	9
            Site Characteristics	12
            Materials Handling Required by the Technology	13
            Personnel Requirements	13
            Potential Community Exposures	,13
            Potential Regulatory Requirements	13

4.      Economic Analysis	'.	19

            Site-Specific Factors Affecting Cost	19
            Basis of Economic Analysis	19
References
.23

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                                        Contents (Continued)
Appendices
        A. Vendor's Claims for the Technology	25

            Introduction	25
            DuPont/Oberlin Microfiltration Technology	:	25
            Applications of the DuPont/Oberlin Microfiltration Technology	26
            Summary	26
            References	26

        B.  SITE Demonstration Results	27

            Introduction	27
            Site Description	•.	27
            Site Contamination Characteristics	27
            Review of SITE Demonstration	,	27
            Experimental Design	30
            Review of Treatment Results	31
            Conclusions	35
            References	46

        C.  Case Studies	47

            Introduction	47

            Case Study  C-l, Westinghouse Savannah River Site, Aiken, South Carolina	48
             Facility Operations	48
             System Performance	;	48
             Costs	50
             Conclusions	50

            Case Study C-2, Dupont Electronics Materials, Inc., Manati, Puerto Rico	51
             Facility Operations	:	51
             System Performance	:	51
             Costs	51

            Case Study C-3, DuPont Electronics, Sun Valley, California	52
             Facility Operations	52
             System Performance	52
             Costs	52
                                                      VI

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                                                  Figures
2-1     DuPont/Oberlin Microfiltration Treatment System	5
2-2     Schematic of DuPont/Oberlin Microfiltration Unit	6
2-3     Steps in a Typical Microfiltration Unit Operating Cycle	7
B-l     PZS Site Location Map	28
B-2     Microfiltration System Sampling Locations	  33
B-3     Zinc Concentration Profiles for Phase 1 Runs	           35
B-4     TSS Concentration Profiles for Phase 1 Runs	37
B-5     Filter Cake Solids for Phase 1 Runs	38
B-6     Zinc Concentration Profiles for Phase 2 Runs	           39
B-7     TSS Concentration Profiles for Phase 2 Runs	40
B-8     Filter Cake Solids for Phase 2 Runs	41
B-9     Comparison of Filtrate Quality for Reproducibility
        Runs with Regulatory Thresholds	                  42
B-10    Filter Cake Composition for Reproducibility Runs	.,,          43
B-ll    Tyvek® Performance for Reusability Runs	.,           44
B-12    Filtrate Particle Size Distribution for Reproducibility Runs	;           45

                                                  Tables
2-1     Comparison of Sludge Dewatering Technologies	            g
3-1     Regulations Summary	_           14
4-1     Estimated Costs Associated with DuPont/Oberlin Microfiltration Systems	20
B-l     Operating Conditions for the Demonstration Runs	           32
B-2     Analytical and Measurement Methods	           34
C-l-1   Operating Data for the DuPont/Oberlin Microfiltration System	49
                                                      VII

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                                         Acknowledgments
    This report was prepared under the direction and coordination of Mr. John Martin, U.S. Environmental Protection
Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Project Manager and Demonstration Section Chief in
the Risk Reduction Engineering Laboratory (RREL), Cincinnati, Ohio. Contributors and reviewers for this report were Ms.
Linda Fiedler of EPA's Office of Solid Waste and Emergency Response, Washington, D.C.; Mr. Gordon Evans,  Mr. Paul
dePercin, and  Mr. Robert Stenburg of EPA RREL, Cincinnati, Ohio; Dr. Ernest Mayer of E.I. DuPont de Nemours and
Company, Inc., Newark, Delaware; and Dr. Thomas Oberlin of the Oberlin Filter Company, Waukesha, Wisconsin.

    This report was prepared for EPA's SITE program by Dr. Kirankumar Topudurti, Mr. Stanley Labunski, Mr. Andrew
Suminski, Ms. Carla Buriks, Mr. Michael Keefe, and Mr. Jack Brunner of PRC Environmental Management, Inc.
                                                     VIII

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                                                  Section 1
                                           Executive Summary
Introduction
     The DuPont/Oberlin microfiltration technology was
evaluated under the U.S. Environmental Protection Agency's
(EPA) Superfund Innovative Technology Evaluation (SITE)
program.   The DuPont/Oberlin microfiltration technology
demonstration was conducted at the Palmerton Zinc Superfund
(PZS) site in Palmerton, Pennsylvania, during April and May
1990.  This technology is designed to remove solids that are
0.1 micron in diameter, or larger, from liquid wastes.  Liquid
wastes with dissolved contaminants (for example, groundwater
with dissolved metals) must first be treated with a precipitating
agent to convert the dissolved contaminants into particulate
form.  The treated waste can then be filtered through the
microfiltration unit, which produces two end products: filter
cake and filtrate.  Prior to filtration, a filter aid/cake stabilizing
agent may  be added to improve the filter cake's dewatering
characteristics and bind the precipitated metals to the cake.
The microfiltration unit can be manufactured as an enclosed
unit, requires little attention during operation,  is transport-
able, and can be trailer mounted.

    The technology  demonstration had the following four
objectives:

     1.  Assess the technology's ability to remove zinc
        from  the groundwater at  the  PZS site under
        different operating conditions
    2.  Evaluate the microfiltration system's ability to
        dewater the metals precipitate from the treated
        groundwater at the PZS site
    3.  Determine the system's ability  to produce  a
        filtrate and a filter cake that meet applicable
        disposal requirements
    4.  Develop  information required  to estimate the
        operating costs for the treatment system

    The purpose of this report is to present information from
the SITE demonstration and  several case studies that are
useful for implementing the DuPont/Oberlin microfiltration
technology at Superfund and Resource  Conservation and
Recovery Act (RCRA) hazardous  waste sites.   Section 2
presents an overview of the  SITE program, describes the
DuPont/Oberlin microfiltration technology,  and lists key
contacts.  Section  3  discusses information relevant to the
technology's application, including pre- and post-treatment
requirements, site characteristics, operating and maintenance
requirements, potential community exposures, and  poten-
tially applicable environmental regulations.  Section 4 sum-
marizes the costs associated with implementing the technol-
ogy.  Appendices A  through  C include the following: the
vendor's claims regarding the automatic pressure filter and
 microporous Tyvek® filter material, a summary of the SITE
 demonstration results, and three case studies.

 Overview of the SITE Demonstration
    The shallow groundwater at the PZS site was selected as
 the  waste  stream for  evaluating  the DuPont/Oberlin
 microfiltration system. This groundwater was primarily con-
 taminated with high levels of zinc (400 to 500 mg/L) and
 trace levels of cadmium (1 mg/L), copper (0.02 mg/L), lead
 (0.015 mg/L), and selenium (0.05 mg/L). The pH and alka-
 linity of the groundwater were about 4.5  and 15 mg/L as
 calcium carbonate, respectively.

    During the SITE demonstration, the microfiltration sys-
 tem treated about 6,000 gallons of shallow groundwater from
 well RCRA-4.  Lime was added to the groundwater to raise
 the pH and precipitate the dissolved metals. A filter aid/cake
 stabilizing agent, called ProFix, was also added to the pre-
 treated groundwater prior to microfiltration.

    The SITE demonstration was performed in four phases
 and  was designed to evaluate the microfiltration system's
 ability to remove zinc from the groundwater, produce a dry
 filter cake, and produce a filtrate and a filter cake that met
 regulatory disposal requirements.  Phases 1 and 2 involved
 nine runs each, and Phases 3 and 4 involved two runs each.
 In Phase 1, chemical operating parameters (pH  and  ProFix
 dose) were varied, while the filter operating  parameters
 (blowdown  pressure and blowdown time) were kept  con-
 stant. In Phase 2, the filter operating parameters were varied,
 while the chemical operating parameters were kept constant.
 Phases 3 and 4 were performed  at the overall  optimum
 operating conditions determined during Phases 1 and 2. Phase
 3 runs were performed to evaluate the reproducibility of the
 microfiltration system's  performance.  Phase 4 runs were
 performed to evaluate the reusability of the Tyvek® filter
 material.

Results from the SITE Demonstration
    The following operating conditions from Phases 1 and 2
 were determined to be the overall optimum operating condi-
 tions for the demonstration: a precipitation pH of 9, a ProFix
dose of 12  g/L, a  blowdown pressure of 38 psig, and a
blowdown time of 0.5 minute.  At these optimum conditions,
the microfiltration system achieved zinc and total suspended
solids (TSS) removal efficiencies of about 99.95 percent and
a filter cake solids content of 41 percent.  The zinc and TSS
removal efficiencies, and the filter cake solids content, were
unaffected by  the repeated use (six cycles) of the Tyvek®
filter material.  This indicates that the Tyvek® filter media
                                                       1

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could be reused without adversely affecting the microfiltration
system's performance.

    The filter cake passed the paint filter liquids test in all
the demonstration runs. Also, a composite filter cake sample
from the 22 demonstration runs passed both the extraction
procedure toxicity and toxicity characteristic leaching proce-
dure (TCLP) tests. This indicates that the filter cake cpuld
be disposed of in a  non-hazardous waste landfill. PrpFix
comprised between 80 and 90 percent of the filter cake
solids.  The remaining solids consisted of precipitated met-
als, TSS from the groundwater, and any unreacted lime.

    The filtrate met  the applicable National Pollutant Dis-
charge Elimination System  (NPDES) permit limits,  estab-
lished for disposal into a local waterway, for metals and TSS
at the 95 percent confidence level.  However, the filtrate did
not meet  the  NPDES limit for pH.  The  filtrate pHlwas
typically 11.5, while  the upper pH limit is 9. This indicates
that the filtrate may require pH adjustment prior to disposal.

Results from the Case Studies
    Information  on  the  DuPont/Oberlin microfiltration
technology's performance at three facilities was evaluated to
provide additional performance data.  These facilities were:

    1.  Westinghouse Savannah  River Site,  Aiken,
        South Carolina
    2.  DuPont  Electronics Materials,  Inc., Manati,
        Puerto Rico
    3.  DuPont Electronics, Sun Valley, California

    Facility 1 treats process wastewaters from metal finish-
ing and aluminum forming operations and from an autoclave
testing operation. Wastewaters from the first two operations
contain 3  mg/L of uranium, 180 mg/L of aluminum, 12 mg/L
of nickel,  and generally low levels of lead, chromium, copper,
and zinc,  mostly in  dissolved form.  These wastewaters
undergo  equalization, precipitation, flocculation,, and
microfiltration.  Wastewater from the autoclave  operation
contains 16 mg/L of uranium oxides and undergoes only
equalization and  microfiltration. Prior to microfiltration, a
filter aid  (PerFLO 30SP)  and a cationic polymer (Praestol
K144L) are added to the pretreated waste. The filtrate meets
all NPDES permit limits (uranium, other metals, pH, and
TSS).  The  filter cake is a mixed waste containing 'both
hazardous and radioactive material.   Prior to disposal, the
filter cake is stabilized and solidified with cement  and  is
subject to land disposal restrictions.

    Facility  2 produces about 2,000 gallons  per day of
wastewater containing 1,000 to 5,000 parts per million (ppm)
of glass paniculate matter, called frit, and 2,000  to  10,000
ppm of TSS.  This wastewater does not require pretreatrhent;
however, prior to microfiltration, a volcanic aluminum sili-
cate filter aid and an organic polymer are added  to the
wastewater.  After microfiltration, the filtrate passes through
two cartridge filters  arranged in series.   These  additional
filters,  rated at 10 microns and 1 micron, are provided  to
ensure high removal of particulates.  According to the facil-
ity, the microfiltration system removes nearly all paniculate
matter.

    Facility 3 generates wastewater from its ceramic powder
manufacturing process. Wastewater characteristics vary daily,
depending on the specific operations performed. Generally,
the wastewater contains, a mixture of metal oxides and titan-
ates.  Lead and TSS  levels typically  range from 0.5 to 5
percent. Pretreatment is not needed since most metals are in
the  form  of  suspended  solids.  However,  prior  to
microfiltration, a diatomaceous earth filter aid and a polymer
(Praestol K122L) are added to improve the cake solids con-
tent and its dewatering characteristics.  The filtrate meets all
local sewer discharge limits and contains typically 0.2 to 0.4
ppm of soluble  lead and 5 ppm  of TSS.  The filter cake
contains about 50 percent solids, but it is considered a haz-
ardous waste based on TCLP test results.  DuPont plans to
use ProFix in lieu of diatomaceous earth to eliminate off-site
stabilization and reduce operating costs.

    Operating and maintenance costs are minimal at all three
facilities, and no major operating problems  have been cited.

Waste Applicability
    The  DuPont/Oberlin microfiltration technology can be
applied to groundwater and industrial wastewaters containing
metals in paniculate form and other suspended  solids.  Met-
als in dissolved form must first be converted to an insoluble
form prior to microfiltration. Potential sites for applying this
technology to contaminated groundwater include Superfund
and RCRA corrective action sites where groundwater is
contaminated with metals from electroplating/metal finishing
wastes, semiconductor and other electronic component
manufacturing waste  streams, metal forming and  uranium
manufacturing wastes, and  other sources  of metal-bearing
wastes.

Economics
    An economic analysis was performed that  examined 12
separate  cost categories for two microfiltration systems:  a
2.4-square foot unit, similar to the unit used during the SITE
demonstration,  and a 36-square foot  unit, the largest unit
currently in use.  This analysis assumed that the microfiltration
systems  would operate continuously  (24 hours per day, 7
days per week) for 1 year.  The economic analysis covered a
 1-year period so  that annual operation and  maintenance
(O&M) costs could be reliably estimated.  Annual O&M
costs were estimated to be $213,000  and  $549,100 for the
2.4- and 36-square foot units, respectively, with correspond-
ing annual throughputs of  525,600 gallons  and 7,884,000
gallons.  The cost analysis assumes that the filter cake and
filtrate will be  disposed of as non-hazardous wastes.  One-
time  capital costs were $369,300 for the smaller unit and
$1,251,200 for the larger unit. Minimal cost data were avail-
able from  the case  studies presented in Appendix C.  How-
ever, one of the case study facilities provided an O&M cost
of $5 per 1,000 gallons of wastewater treated.   This cost
included electricity and expenses for replacing polymer, fil-
 ter aid, and filter media.

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                                                  Section 2
                                               Introduction
    This section provides background information about the
Superfund Innovative Technology Evaluation (SITE)  pro-
gram, discusses the  purpose of this applications analysis
report, and  describes  the  DuPont/Oberlin microfiltration
technology.   The  persons  to  be contacted  for additional
information  about  mis  technology, the  SITE program, and
the demonstration site are listed at the end of this section.

Purpose, History, and Goals of the SITE Program
    In response  to  the Superfund  Amendments  and
Reauthorization Act of 1986 (SARA), EPA's Office of Re-
search and Development (ORD) and Office of Solid Waste
and Emergency  Response (OSWER) established the SITE
program  to (1) accelerate the development, demonstration,
and use  of  new or  innovative  technologies to clean up
Superfund sites, (2) foster further investigation and develop-
ment of treatment technologies that are still at the laboratory
scale, and (3) demonstrate and evaluate new or innovative
measurement and monitoring technologies.

    The primary purpose of the SITE program is to enhance
the development and demonstration, and thereby promote the
commercial  availability, of innovative  technologies appli-
cable  to Superfund sites. Major goals of the SITE program
are to:

        Identify and  remove impediments to the
        development and commercial use of alternative
        technologies
    •    Demonstrate  the more promising innovative
        technologies in  order to  establish reliable
        performance and  cost  information  for  site
        cleanup decision making
    •    Develop procedures and policies that encourage
        selection  of available alternative treatment
        remedies at Superfund sites
    •    Structure a development program that nurtures
        emerging technologies

    EPA recognizes  that a number of forces inhibit  the
expanded use of alternative  technologies at Superfund sites.
One of the  objectives  of the program  is  to  identify these
impediments and remove them or develop methods to  pro-
mote the  expanded use of alternative technologies.

    Another objective  of the SITE program is  to demon-
strate  and evaluate selected technologies.  This is a signifi-
cant ongoing effort involving ORD, OSWER, EPA Regions,
and the private sector. The demonstration program serves to
test field-ready technologies and provide Superfund decision
makers with  the information necessary to evaluate the use of
these technologies for future cleanup actions.
    Other aspects of the SITE program include developing
procedures and policies  that match available  technologies
with wastes, media, and sites for actual remediation, and
providing assistance in nurturing the development of emerg-
ing innovative technologies from the laboratory- or bench-
scale to the full-scale stage.

    Technologies chosen for a SITE demonstration must be
innovative, pilot- or full-scale applications  and offer some
advantage over existing technologies.  Mobile  technologies
are of particular interest. Each annual round of demonstrations
includes approximately 10 technologies.

Documentation oj'the SITE Demonstration Results
    The results of each SITE demonstration are incorporated
in two documents: the technology evaluation report and the
applications analysis report.  The technology evaluation re-
port provides a comprehensive description of the demonstra-
tion  and its results.  A likely audience for the technology
evaluation report are engineers resiponsible for performing an
in-depth evaluation of the technology for a specific site and
waste situation.  These technical evaluators seek to under-
stand, in detail, the performance of the technology during the
demonstration and the advantages, risks, and  costs of the
technology for the given application.   This information is
used to produce conceptual designs in sufficient detail for
evaluators to make preliminary cost estimates for the demon-
strated technology.

    The applications analysis report is intended  for technical
decision makers responsible for screening available remedial
alternatives.  The principal  use of the applications analysis
report is to assist in determining whether the specific tech-
nology should be considered further as an option for a par-
ticular cleanup situation. The report  discusses the advan-
tages, disadvantages, and limitations of the technology in  its
broadest application. Costs  of the technology  for different
applications are estimated based on available data for  pilot-
and full-scale applications. The report discusses the factors,
such as site  and waste characteristics,  that have a major
impact on cost and performance. If the candidate technology
appears to  meet the needs of  the site  engineers,  a  more
thorough analysis will be conducted, based  on  the technol-
ogy evaluation report, applications analysis report, and infor-
mation from remedial investigations for the specific site.

Purpose of the Applications Analysis Report
    To encourage the general use of demonstrated technolo-
gies, EPA will provide information on the  applicability  of
each technology to certain sites and wastes, other than  those

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already tested, and will study the costs of these applications.
Available information and data are presented  through the
applications analysis reports. These reports attempt to syn-
thesize available information on  the technology and draw
reasonable conclusions as  to its broad range applicability.
The applications analysis report is useful to those consider-
ing the technology for Superfund and other hazardous waste
site cleanups and represents a  critical step  in the develop-
ment and commercialization of the treatment technology.

    Each SITE demonstration will evaluate the performance
of a technology in treating a particular waste found  at the
demonstration site.  To obtain data with broad applications,
attempts will be made to select waste frequently found at
other Superfund sites. In many cases, however, the waste at
other sites will differ in some way from the waste tested.
Thus, the successful demonstration of a technology at one
site does not ensure that it will work equally well at other
sites. Data obtained from the demonstration may have to be
extrapolated to estimate the total operating range over which
the technology performs satisfactorily. .This extrapolation
should be  based upon both demonstration data and other
information available from case studies about the technology.

    The amount of available data for the evaluation of an
innovative technology varies widely. Data may be limited to
laboratory  tests on  synthetic wastes or may include perfor-
mance data on actual wastes treated at pilot- or full-scale
treatment systems. In addition, there are limits to conclusions
regarding Superfund applications that can be drawn from a
single field demonstration.  A successful field demonstration
does not necessarily ensure that a technology will be widely
applicable  or fully developed to a commercial scale.

Technology Description
    In February 1988, E.I. DuPont de Nemours and  Com-
pany, Inc.  (DuPont) and Oberlin Filter Company (Oberlin)
submitted  to EPA a joint  proposal for demonstrating their
microfiltration  technology  under the SITE program.  EPA
selected the DuPont/Oberlin microfiltration technology for
demonstration under the SITE program in June 1988.

    DuPont/Oberlin's microfiltration technology is designed
to remove solids from liquid wastes. It is suitable for treating
landfill leachate, groundwater, and liquid industrial wastes
containing metals (in soluble or insoluble form) and particu-
lates. Since the microfiltration system is designed to remove
particles that are 0.1 micron or larger in diameter, dissolved
contaminants must first be converted to a paniculate fprm.
For example, groundwater with dissolved metals must \ first
be treated with a precipitating agent, such as lime, to convert
the dissolved metals into  paniculate form, such as  metal
hydroxides.  After the dissolved metals are converted to a
paniculate form, the liquid waste can be filtered through the
microfiltration unit  The microfiltration unit produces; two
end products: filter cake and filtrate.  To produce a filter cake
that has a low moisture content and a filtrate that has a low
solids content, DuPont/Oberlin normally uses a filter  aid or
filter aid/cake stabilizing agent. For the SITE demonstration
conducted at thePZS site during April and May 1990, DuPont
selected a silicate-based filter aid/cake stabilizing agent known
as ProFix, which is manufactured by EnviroGuard, Inc. of
Houston, Texas.
    The microfiltration system can be manufactured as an
enclosed unit, requires little attention during operation, is
mobile, and can be trailer mounted. A typical configuration
of the DuPont/Oberlin microfiltration system (including pre-
treatment and principal treatment operations) to treat ground-
water contaminated with dissolved metals is shown in Figure
2-1.  Since the pretreatment operations  (for example,  pH
adjustment and filter aid addition) of the microfiltration tech-
nology  vary from one application to another, these opera-
tions are not described in this section. However, a discus-
sion on pretreatment  operations is presented in Section 3
under "Factors Influencing Effectiveness." Principal  treat-
ment operations  of the  microfiltration technology and its
innovative features are described below.

Principal Treatment Operations
    A  schematic  of the DuPont/Oberlin microfiltration unit
is shown  in Figure 2-2.  This microfiltration  unit  is an
automatic pressure filter that operates on pressure signals and
uses a  low-cost membrane filter, Tyvek® T-980, a  thin, du-
rable spunbonded olefin fabric developed by DuPont.  The
microfiltration  unit, developed by Oberlin, has two cham-
bers, an upper chamber for feeding waste through  the filter
media, and a lower chamber for collecting the filtrate.  The
upper chamber moves vertically, while the lower chamber is
fixed.  The Tyvek® filter lies between these two chambers.
These units are available in several sizes: the smallest unit
has a filtering area of 2.4 square feet and the largest unit has
a filtering area of 36 square feet.  According to the technol-
ogy developers, about 40 percent  of  the units in operation
have the 2.4-square foot filtering area. The unit used in the
SITE demonstration also has a filtering area of 2.4 square
feet and is 64 inches long, 33 inches wide, 83 inches high,
and weighs approximately 1,300 pounds.
    A  typical operating cycle of the microfiltration unit con-
sists of four steps: (1) initial filtration/filtrate recirculation;
(2) main  filtration/cake forming; (3) cake drying;  and (4)
cake discharge. Figure 2-3  shows the steps involved in the
operation  of the microfiltration unit.

    At the start of a typical filtration cycle, the upper cham-
ber is lowered to form  a liquid-tight seal against the Tyvek®.
The liquid feed waste containing paniculate  matter is then
pumped, at an  initial air pressure of 10 psig,  into the upper
chamber and filtered through the Tyvek*. During  this pro-
cess, solids are deposited on the Tyvek® filter. This solids
buildup increases resistance to liquid flow through the Tyvek®.
To keep the filtration rate constant, air pressure to the pump
is automatically increased throughout the filter cycle. During
the initial 30 seconds to 1 minute of the cycle, the filtrate is
recirculated to  the precipitation tank  to keep the quality of
filtrate high. At the end of 1 minute, recirculation stops and
the filtrate is drained to the filtrate collection tank.

    Liquid waste is pumped to the microfiltration unit until
the air pressure to the pump reaches 55 psig (a pressure drop
of approximately  45 psig across the filter). Liquid feed waste
to the microfiltration unit is then shut off,  and pressurized air
(30-45 psig) is fed into the upper chamber to dry  the filter
cake. The air forces any liquid remaining  in the upper cham-
ber and in the filter cake pores to pass through the Tyvek®
into the lower chamber. The air pressure applied to drain the

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                   Groundwater
                                                                                                   Filter Cake
                                                                                                   Filter Cake
                                                                                                     Storage
          LX
     Lime Slurry Tank
                                 ProFix Slurry Tank
 Figure 2-1. DuPont/Oberlin MicrofMiration Treatment System.

liquid  remaining in the  upper chamber, and dry the filter
cake, is called the blowdown pressure.  Once the liquid is
drained from  the upper chamber and the filter cake,  air
breaks through the filter cake.  After breakthrough occurs, air
continues to be fed through the upper chamber for a preset
time interval to further dry the cake. The preset time interval
is called the blowdown time.  During the cake drying period,
the filtrate is sent back to the precipitation tank to keep the
quality of filtrate high. At the end of the blowdown time, the
air supply to the upper chamber is automatically shut off, the
upper chamber is raised,  and the filter cake is automatically
discharged. Clean Tyvek® is then drawn from a roll into the
microfiltration unit for the next cycle.

Innovative Features
    The DuPonl/Oberlin microfiltration technology uses a
new, low cost membrane filter (Tyvek® T-980) that can be
fed continuously to an automatic pressure filter to dewater
sludges effectively. Through  proper  pretreatment,  such as
chemical precipitation, this  technology can be used to re-
move dissolved metals from liquid wastes at a cost lower
than several  other treatment options, such  as  precipitation
followed by clarification and conventional filtration, ion ex-
change, reverse osmosis, and electrolysis. When used in
conjunction with a filter aid/cake stabilizing agent, the DuPont/
Oberlin microfiltration technology produces a dry and stabi-
lized cake that can be landfilled.

    The DuPont/Oberlin microfiltration system has several
innovative features that make it more effective than conven-
tional microfiltration systems. The most significant of these
features is  DuPont's  Tyvek® T-980 filter media, which is
designed to remove particles that are 0.1 micron or larger in
diameter.  The high strength of this media, under both wet
and dry conditions,  permits  continuous  operation in the
microfiltration unit.  Also, the smooth, slick surface of the
Tyvek® T-980 media facilitates cake release and separation.

    Pressure filters such as the DuPont/Oberlin microfiltration
units are becoming a more popular means of dewatering
sludges and removing precipitated, metals from liquid waste
streams.  Pressure filters generally produce a filter cake with
a solids content high  enough to meet landfill requirements,

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                                                    Pressurized
                                                         Air
                           Air  Cylinder
                                                                                          Waste
                                                                                          Feed
               Filter  Cake
           Used Tyvek
              Air Bags

           Waste Feed  Chamber


                                  ®
                     Clean  Tyvek



                Filter  Belt
                  Filtrate Chamber
                                                     Filtrate
                                                    Discharge
Rgure 2-2. Schematic of DuPont/Oberlin Microfiltration Unit.
giving it a significant advantage over other dewatering meth-
ods.  Also, automation makes pressure filters more appeal-
ing. Table 2-1 compares several sludge dewatering options.

    The  DuPont/Oberlin microfiltration technology i uses
Oberlin's automatic pressure filter, which has certain advan-
tages over other  conventional  pressure filters.' The
microfiltration unit uses a continuous roll of filter media and
automatically dispenses the filter cake, eliminating the;need
for add-on systems such as plate shifters and cake vibrators.
When used in conjunction with the Tyvek® T-980 media, the
system can effectively dewater sludge at a maximum pres-
sure of 30 to 50 psig,  requiring less energy than other
pressure filters, which may operate at a maximum pressure
above 200 psig.  Also, the Tyvek® T-980 media is dispensed
from a roll and the cake discharge is fully automated. The
automatic  cake discharge and electronic controls, based on
either discrete relays and timers or programmable logic con-
trol, enable the microfiltration unit to run without significant
operator attention, except for filter aid makeup, media roll
replacement, and cake removal.

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  /.    INITIAL FILTRATION/FILTRATE RECIRCULAVON       2.  MAIN FILTRATION/CAKE FORMING
                 Pressurized  Air

                       \


                       i Valve  B (Closed)

                         Valve A (Open)
                   IMM^^^ _ Waste
                                          Feed
                              Air Bags
                              Waste Feed Chamber
nitrate
Chamber
                                    Clean Tyvek
                                      Reclrculatton

                             Valve D (Closed)
                                                              Filter
                                                              Cake
                                                            Filtrate
                        nitrate
                        Collection
                                                                                                  . Waste
                                                                                                   Feed
                                                                                    M D (Open)
                                                                                 Filtrate
                                                                                 Collection
            3.    CAKE DRYING
                                                                  4.   CAKE DISCHARGE
    Filter
    Cake
   Filtrate
               Pressurized Air
                    \

                    ( B (Open)
                      A (Closed)
                   A  i
                             D (Closed)
                                                                                    B (Closed)
                                                                                          Waste Feed
                                                                                          Chamber Raised
                                                                                              Clean Tyvek
                                                                                              Advanced
                                                                                    IH D (Closed)
Figure 2-3. Steps in a Typical Microfiltration Unit Operating Cycle.

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Table 2-1.  Comparison of Sludge Dewatering Technologies

Technology                       Advantages	^^
                                             Disadvantages
Basket Centrifuge
Low energy consumption; low chemical
consumption; low labor requirements;
prescreening not required
                                                                             Low cake solids content
Solid Bowl Centrifuge
Low chemical consumption; low
labor requirements
Low cake solids content; prescreening required;
high energy consumption
Vacuum Filter


Sludge Drying Bed
Low labor requirements
Low cake solids content; high energy consumption;
high chemical consumption; prescreening required
High cake solids content possible;                   High labor requirements; large land area
low energy consumption; low chemical consumption;    requirements; climatic influences; aesthetically
prescreening not required                         unpleasing
Gravity/Low Pressure Device
Low energy consumption; low labor
requirements; prescreening npt required
                                                                              Low cake solids content; high chemical consumption
Bell Filter Press
High cake solids content; low energy consumption      Prescreening required; high chemical consumption;
                                             high labor requirements
Plate Hlter Press
Very high cake solids content
Prescreening required; high chemical consumption;
high labor requirements; high energy consumption
 Pressure Filter
Very high cake soh'ds content; low labor requirements   Prescreening required; high chemical consumption;
                                             high energy consumption
 Note:  Based on U.S. EPA, 1982.
 Key Contacts
      Additional  information on  the  DuPont/Oberlin
 microfiltration technology, the  SITE program,  and  the
 Palmerton Zinc Superfund  site (demonstration site) can be
 obtained from the following sources:

 The DuPont/Oberlin Microfiltration Technology
         Ernest Mayer
         E.I. DuPont de Nemours and Company, Inc.
         Engineering Department L1359
         P.O. Box 6090
         Newark, DE  19714-6090
         (302) 366-3652

         Thomas  Oberlin
         Oberlin Filter Company
         404 Pilot Court
         Waukesha,WI  53188
          (414) 547-4900
                              The SITE Program
                                       John Martin
                                       U.S. Environmental Protection Agency
                                       Office of Research and Development
                                       Risk Reduction Engineering Laboratory
                                       26 West Martin Luther King Drive
                                       Cincinnati, OH 45268
                                       (513) 569-7758

                              The Palmerton Zinc Superfund Site
                                       Tony Koller
                                       U.S. Environmental Protection Agency
                                       Region 3 (3HW22)
                                       841 Chestnut Street
                                       Philadelphia, PA  19107
                                       (215) 597-6906

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                                                   Section 3
                                   Technology Applications Analysis
     This section addresses the applicability of the DuPont/
 Oberlin microfiltration technology to treat liquid wastes con-
 taining paniculate matter and metals in suspended or  dis-
 solved  form.   The technology's applicability is  presented
 based on the results from the DuPont/Oberlin microfiltration
 system demonstration performed under the  SITE program
 and other applications of the DuPont/Oberlin system pre-
 sented in Appendix C.  Since the results of the SITE demon-
 stration provided an extensive database, evaluation of the
 technology's effectiveness and its applicability to  other po-
 tential cleanup operations is mainly based on the SITE dem-
 onstration results presented  in Appendix B.  The vendor's
 claims regarding the applicability  and performance of the
 DuPont/Oberlin  microfiltration technology are included in
 Appendix A.

     A summary of the effectiveness of the DuPont/Oberlin
 microfiltration technology is presented in this section,  fol-
 lowed by a discussion of site characteristics, materials handling
 requirements, personnel requirements, potential community
 exposures, and  potential  regulatory requirements for  the
 DuPont/Oberlin technology.

 Effectiveness of the DuPont/Oberlin Technology
     The effectiveness of the DuPont/Oberlin  technology is
 presented based on the results from the SITE demonstration
 and three other case studies  of the technology.  After sum-
 marizing the results from the  SITE demonstration and the
 case studies, this report describes  factors influencing  the
 effectiveness of the technology.

 SITE Demonstration Results
     The SITE demonstration was conducted at the Palmerton
 Zinc Superfund (PZS) site in Palmerton, Pennsylvania, dur-
 ing April and May 1990. During the SITE demonstration, the
 microfiltration system  treated 6,000 gallons of groundwater
 contaminated with high levels of zinc (400 to 500 mg/L) and
 trace levels of cadmium (1 mg/L), copper (0.02 mg/L), lead
 (0.015 mg/L), and selenium (0.05 mg/L).

    The objectives  of the DuPont/Oberlin microfiltration
technology demonstration  performed under the SITE pro-
gram were to:

    •   Assess the technology's ability to remove zinc
        from the groundwater at the PZS site under
        different operating conditions
    •   Evaluate the microfiltration system's ability to
        dewater the metals precipitate from treated
        groundwater at the PZS site
        Determine the system's  ability  to produce a
        filtrate and a  filter cake that meet applicable
        disposal requirements
        Develop  information required to estimate the
        operating costs for the treatment system, such
        as electrical power consumption and  chemical
        doses
    The technology evaluation was performed in four phases.
Phases 1 and 2 involved nine runs each, and Phases 3 and 4
involved two runs each.  In Phase 1, chemical operating
parameters (precipitation pH and ProFix dose) were varied,
and the filter operating parameters (blowdown pressure and
blowdown  time) were kept constant. In Phase 2, the filter
operating parameters were varied, and the chemical operat-
ing parameters were kept constant. Phase 3 runs were per-
formed to evaluate the reproducibility  of the microfiltration
system's performance. Phase 4 runs were performed to evalu-
ate the reusability of the Tyvek® filter.

    Appendix B  summarizes information from the SITE
demonstration, including (1) site characteristics, (2) contami-
nated groundwater characteristics, (3) microfiltration system
performance, and  (4) technology evaluation results.  Key
findings of the demonstration are given below.

        The DuPont/Oberlin microfiltration system
        achieved  the following: (1) zinc  and total
        suspended solids (TSS) removal efficiencies of
        99.69 to  99.99  percent  and (2)  solids  in  the
        filter cake of 30.5 to 47.1 percent. At the overall
        optimum conditions (precipitation pH  of 9,
        ProFix dose of  12 g/L, blowdown pressure of
        38 psig, and blowdown  time of 0.5 min.), the  ,
        zinc and TSS removal efficiencies were about
        99.95 percent, and the filter cake solids were
        about 41 percent.
        ProFix contributed a significant portion  (80 to
        90 percent)  of  solids to the  filter cake. The
        remaining solids were due to precipitated metals,
        TSS from  the untreated groundwater, and any
        unreacted lime.
        The zinc and TSS  removal efficiencies and the
        filter cake percent solids were unaffected by the
        repeated use (six cycles) of the Tyvek® filter
        media. This  indicates that the Tyvek®  media
        could be reused without adversely affecting the
        microfiltration system's performance.
       The filtrate met the applicable National Pollutant
        Discharge Elimination System (NPDES) permit

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        limits, established for discharge  into a  local!
        waterway, for metals andTSS at the 95 percent
        confidence level. However, the filtrate did not
        meet the NPDES limit for pH. The filtrate pH
        was typically 11.5, while the upper discharge
        limit is 9.
    •   The filter cake passed the paint  filter liquids
        test for all runs. Also, a composite filter cake
        sample from the demonstration runs passed the
        extraction procedure (EP) toxicity and toxicity
        characteristic leaching procedure (TCLP) tests.

Other Case Studies' Results
    Several   other  studies  on  the  DuPont/Oberlin
microfiltration system have been carried out. DuPont/Oberlin
has made the results  from  three case studies available to
EPA. These studies are summarized in Appendix C. A brief
summary of  the effectiveness of the  DuPont/Obeirlin
microfiltration technology at the three facilities is presented
below.

    The first case study describes the effectiveness of two
DuPont/Oberlin microfiltration units in treating wastewaters
from a metal finishing and aluminum forming operation and
from an autoclave process both at the Westinghouse Savan-
nah  River site in Aiken, South Carolina. The wastewater
from metal finishing and aluminum forming operations con-
tains about 3 mg/L of uranium, 180 mg/L of aluminum', 12
mg/L of nickel, and low levels of lead, zinc, copper, and
chromium mostly in dissolved form. The wastewater from
the autoclave process contains about 16 mg/L of insoluble
uranium oxides.

     At the Savannah River site, wastewater containing soluble
metals is  treated by equalization, precipitation, flocculation,
and microfiltration, and wastewater containing insoluble metal
oxides  is treated by  equalization and microfiltration. ;The
Savannah River site used Tyvek® 1042B as the filter media
for several years. However, during peak flow situations, the
two DuPont/Oberlin  systems could not  provide adequate
treatment. Therefore, DuPont conducted several tests to im-
prove the treatment capacity of the filters. During these tests,
DuPont's efforts  to upgrade the microfiltration systems in-
cluded using'new filter media (Tyvek"1 T-980),  filter aidi and
polymer additive.

     Performance of the microfiltration systems was maxi-
mized and their combined  capacity was upgraded by using
Tyvek* T-980 filter  media, in conjunction with PerFLO
30SP filter aid and Praestol K144L cationic polymer. The
volume of filter cake requiring  disposal decreased  by 15
percent. The filtrate and filter cake met both EP toxicity and
TCLP tests. The filtrate also met all NPDES  requirements.
The filter cake is solidified and stabilized  with cement prior
to its disposal as  a mixed waste.

     The second case study describes the removal of particu-
late matter present in  a wastewater  slurry at the DuPont
Electronics Materials, Inc. (DEMI) facility in Manati, Puerto
Rico. DEMI produces a wastewater slurry at a rate of 2,000
gallons per day. The slurry contains 1,000 to 5,000 parts per
million (ppm) of glass particulates and 2,000 to 10,000 :ppm
of TSS. The plant uses a filter aid and an organic polymer
prior to microfiltration. The microfiltration  unit uses Tyvek®
T-980  filter media.  After microfiltration, the filtrate passes
through two cartridge filters arranged in series. These addi-
tional filters, rated at 10 microns and 1 micron, are provided
to ensure high levels of paniculate removal.  According to
DEMI, the microfiltration system removes nearly all panicu-
late matter.

    The third case study describes the removal of suspended
metals from two liquid waste streams produced by the Com-
ponent Materials Division of the DuPont Electronics facility
located in Sun Valley, California. The compositions of the
two waste streams vary according to daily operations at this
facility. However, lead and TSS levels typically range from
0.5 to 5 percent.  The facility  uses  two  7-square foot
microfiltration units that are in two  different locations 1/4 -
mile apart. The microfiltration units  use Tyvek® T-980 filter
media, a filter aid, and a polymer.

    The filtrate meets Los Angeles  sewer effluent limits of
26 ppm  and 5 ppm  for TSS and  zinc, respectively. The
moisture content of the filter cake is about 50 percent. The
filter cake is classified as hazardous waste because it fails the
TCLP test. DuPont plans to use ProFix instead of diatoma-
ceous  earth to eliminate  off-site stabilization  and reduce
operating costs.

    In summary, the DuPont/Oberlin microfiltration technol-
ogy has been demonstrated to be effective in removing TSS
and metals (soluble and insoluble) from liquid wastes. The
technology has also been demonstrated to produce a filter
cake of 40 to 50 percent  solids that passes the  paint filter
liquids test, making the filter cake suitable for land disposal.
However, whether the filter cake must be disposed of as a
hazardous waste or non-hazardous  waste has to be deter-
mined on a case-by-case basis. Also, in some cases, the
filtrate may require post-treatment for pH adjustment prior to
discharge into a waterbody.

Factors Influencing Effectiveness
    Several factors influence the effectiveness of the DuPont/
Oberlin  microfiltration technology. These factors  can  be
grouped into three  categories: (1) waste characteristics,  (2)
operating parameters, and (3) maintenance requirements. Each
of these is discussed below.

Waste Characteristics
    The ability of the DuPont/Oberlin microfiltration system
to remove dissolved metals depends  on certain key waste
characteristics. These include organic and inorganic ligands
(a negatively charged ion or a molecule that forms a complex
with  positively charged metal  ions), the oxidation state of
metallic contaminants, and  oil and grease. Several organic
and inorganic ligands can complex with metals and make the
metals less amenable to precipitation. Organic ligands such
as amino acids  and humic  compounds are known to form
complexes  with  several heavy metals  (for example, with
copper). Inorganic  ligands such as ammonia, cyanide, and
chloride are known to form stable complexes with zinc, iron,
and mercury, respectively. Therefore, it is important to mea-
sure the ligand concentrations and  properly design the pre-
treatment operations to precipitate metals effectively. Another
key waste characteristic is the oxidation state  of metallic
                                                         10

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contaminants.  For example,  hexavalent  chromium is less
amenable to precipitation than trivalent chromium. Therefore,
if chromium is present in the hexavalent state, it needs to be
reduced to the trivalent state prior to precipitation for effective
removal. In addition to these waste characteristics, high lev-
els  of oil and grease may decrease the system's treatment
efficiency.

Operating Parameters
    Operating parameters are those parameters that are var-
ied during treatment to achieve desired removal efficiencies.
Typically,  such  parameters include precipitation pH, filter
aid/cake stabilizing  agent (for pretreatment,  if required),
blowdown  time, and blbwdown pressure (for microfiltration
of sludge). In addition to these  parameters, several  other
operating parameters become important  depending on the
type of pretreatment required. For example, if metals need to
be oxidized or reduced prior to precipitation, the oxidant or
reductant dose and the pH at which this pretreatment must be
carried  out will have to be controlled properly. Only the
typical operating parameters are discussed in this report.

    Precipitation pH depends on the metal to be precipitated
and the type of solid phase formed during precipitation (hy-
droxide, carbonate, or sulfide). The solubility of most metals
follows a U-shape curve because of the amphoteric nature of
most solid phases formed during metal precipitation. This
indicates that usually there is an optimum pH or pH range at
which the solubility of a given metal is at its minimum. The
removal of this metal from liquid wastes  can be maximized
by keeping the precipitation pH close to  the optimum. In a
real-world  situation, however, the liquid  wastes will have
either multiple pH optima or an overall optimum pH range.
Such situations may require conducting sequential precipita-
tion of metals (in case of multiple optima) or setting the
precipitation pH in the overall optimum range (in case of no
multiple optima).  Selection  of precipitation pH could be-
come more difficult, if the liquid waste contains ligands that
form complexes with target metals. In   such a  case, the
precipitation pH should be selected such that the metal com-
plexation is minimized.  However, if such  an approach does
not yield adequate metal removal,  the ligand and/or complex
should be removed prior to metal  precipitation.

    DuPont normally uses a filter aid to improve sludge
dewatering characteristics or a filter aid/cake stabilizing agent
to stabilize the cake and improve  sludge dewatering charac-
teristics. DuPont normally screens several  commercial  prod-
ucts for each application. Typically, higher chemical additive
doses are required to meet TCLP limits. However, a higher
dose  also results  in greater chemical costs and more dry
solids handling.

    Blowdown pressure is the  pressure at which air is ap-
plied to drain residual liquid from  filter cake pores during the
cake drying step of a filtration cycle. Blowdown time  is the
time for which air is applied after it breaks through the filter
cake. Since blowdown pressure and blowdown time control
the filter cake dryness,  these are the key operating param-
eters of the DuPont/Oberlin microfiltration unit. The higher
the values  of these parameters, the higher will be  the filter
cake dryness. However, it should  be noted that as the  target
blowdown pressure increases, so  will the required capacity
and pressure rating of the air compressor. Also the filtration
cycle time (processing time) will increase, if the blowdown
time is increased.

Maintenance Requirements
    The maintenance requirements for the DuPonl/Oberlin
system summarized here are based on a review of the opera-
tion  and maintenance manual  for the microfiltration unit
(Oberlin, 1984) and other published literature (WPCF, 1984;
Karassik, 1986). Regular maintenance by trained personnel
is essential for the system's successful operation. The fol-
lowing components require  routine  maintenance: (1)
microfiltration unit, (2) air compressor, (3) pumps, and (4)
miscellaneous components. A brief summary of the mainte-
nance requirements for  each of these components  is pre-
sented below.

    The microfiltration  unit  hais  several components that
require periodic maintenance. For example, the platen seals
in both the upper and lower platens (chambers) will wear out
and need replacement approximately once a year. Similarly,
air bags will wear out and need replacement once every 3 to
5 years. Seals in the air cylinder (located on  the top of the
filter frame) will also age and leak air. If properly lubricated,
these will require replacement approximately once every 5
years. Standard leak  checks  should be performed  once a
month to identify when platen seals or air bags need re-
placement. The Tyvek® filter media roll also needs to  be
replaced, as needed.  Several moving parts, such as the air
cylinder and pillow  block beaiings, should  be lubricated
with proper lubricants once  every 6  months for smooth
operation of the DuPont/Oberlin unit.

    Oberlin normally uses a reciprocating type of compres-
sor to supply pressurized air to I'Jie microfiltration unit. The
compressor valves should be removed and inspected after
the first 3 months of operation.  The condition of the valves
after this initial inspection will  serve as  a guide to the
frequency of future inspections.  It is generally recommended
that  the valves be inspected at least once a year. The
compressor's shaft packing should also be inspected at fre-
quent intervals, and this packing should be adjusted or re-
placed as often as required. Bearing and piston clearances,
rod alignment, and cylinder bore condition should be checked
at least annually and  adjustments or replacements made to
correct any abnormal conditions.  Since the microfiltration
unit has pneumatic controls, a moisture trap and an air dryer
should be installed at the discharge end of the compressor to
prevent malfunctioning of the microfiltration unit.

    The operation of the DuPont/Oberlin microfiltration
system  typically requires  three to four pumps. Since the
type, size, design, and construction materials of these pumps
may vary from one application to the other, the operators
should review the manufacturer's instruction manuals before
attempting to service any of the pumps. Only general guide-
lines regarding the maintenance of the pumps are outlined
below.  Pumps should be checked twice each shift (When
the operators are on  duty), and any irregularities in their
operation should be addressed immediately following
manufacturer's guidelines. This applies particularly to changes
in the sound of a running  pump, abrupt changes in bearing
temperatures, and stuffing box leakage. The free movement
                                                        11

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of stuffing box glands should be checked semiannually, gland
bolls should be cleaned and oiled, and the packing should be
inspected to determine whether it requires replacement. The
pump and driver alignment should be checked and corrected
if necessary. Oil-lubricated bearings should be drained and
refilled with fresh oil. Grease-lubricated bearings should be
checked to see that they contain the correct amount of grease
and that the grease is still of suitable consistency. During
semiannual  inspections,  worn  out  bearings  should  be re-
placed. A complete overhaul of the pumps is required peri-
odically for smooth operation. The frequency  of complete
pump overhauls will depend on the  pump  service, the pump
construction and materials, the liquid pumped, and an evalu-
ation of the costs of overhaul versus the cost of power losses
resulting from increased clearances or of unscheduled down-
time. Some pumps on very severe service may need a cbm-
plete overhaul monthly, while other applications may require
overhauls only every few years.

    Other components of the DuPont/Oberlin  microfiltration
system, such as valves, flow meters, and pipelines, should be
checked  for leaks and  clogging. The metals precipitation
tank, lime slurry tank, filter aid/cake stabilizing agent slurry
tank, and filtrate collection tank should also be checked for
leaks. Finally, the electrical motors for the mixers used in
tanks should be maintained following manufacturer's guide-
lines.

Site Characteristics
    In addition to influent characteristics and effluent dis-
charge requirements, site characteristics are important when
considering  the use of DuPont/Oberlin's microfiltration tech-
nology. Site-specific factors have  both positive and negative
impacts on  the application of DuPont/Oberlin's technology,
and these should  be considered  before this technology is
selected for  site remediation. These  factors include site grea,
site preparation, site access,  climate, utilities, and services
and supplies.

Site Area
    DuPont/Oberlin units are available in several sizes, with
filtration areas ranging from 2.4 to 36 square feet. During the
SITE demonstration, a  2.4-square foot unit  was used. An
area of 30 feet in  length and 20 feet in width was adequate
for the DuPont/Oberlin  unit and  associated equipment, ex-
cluding influent and  effluent storage tanks.  Larger units
would require slightly larger areas. For example, for the; 36-
square foot  unit, an area of 50 feet  in length and 30  feet in
width should be provided. Areas required for  influent ;and
effluent storage tanks, if needed, may vary depending ort the
flow rate and turnaround time  for any effluent analysis re-
quired prior to disposal of the effluent. Also, an area of 20
feet in length and 15 feet in width is required for  indoor
office space and any on-site laboratory work.

Site Preparation
    The area containing  the DuPont/Oberlin system tanks
should be relatively level. It can  be paved or covered with
compacted soil or gravel. The site geotechnical characteris-
tics (for example, soil bearing capacity) should be evaluated
to identify whether any foundation is required to support the
microfiltration treatment system and storage tanks.

    To clean up contaminated groundwater, extraction wells
and a groundwater collection and transmission system should
be installed so that the groundwater can be pumped to a
central facility where  the DuPont/Oberlin system  will be
located on-site.  Unless the  DuPont/Oberlin microfiltration
system is designed for outdoor use, a temporary tent-like
enclosure will be needed to protect the system from inclem-
ent weather. Tanks will likely be required for untreated and
treated groundwater. Drums or other suitable containers will
also  be needed to store the filter cake. Also, an equipment
and personnel decontamination facility should be provided,
along with one  or more portable chemical toilets or other
suitable sanitary facilities.

Site Access
    Site access requirements for the treatment equipment are
minimal. The site must be accessible to tractor-trailer trucks
of standard size and weight. The roadbed must be able to
support such a vehicle delivering the DuPont/Oberlin system
and tanks.

Climate
    Below-freezing temperatures and heavy rain could have
an adverse impact on the operation of the DuPont/Oberlin
system.  If  below-freezing temperatures are expected for a
long period of time, the DuPont/Oberlin system and influent
and effluent storage tanks should be insulated or kept in a
well-heated shelter, such as a building or shed. The DuPont/
Oberlin system should also be protected from heavy rain.

Utilities
    The  DuPont/Oberlin system requires  potable water and
electricity.  Potable water is required for preparation of lime
and filter aid slurries, for equipment cleanup, and for personnel
decontamination. In some applications, to conserve water,
filtrate may be used instead of potable water.

    The  microfiltration unit typically requires 240-volt, 3-
phase, 60-Hz electrical service. Additional electrical power
(110-volt, single phase), is needed mainly for operating the
mixers in the process tanks,  lighting the office trailer, and
operating the on-site laboratory and office equipment. Elec-
tricity is also needed to provide heat in the on-site trailer and
equipment  shelter area.

    A telephone is required to order supplies, contact emer-
gency services, and provide normal communications.

Services and Supplies
    A number of services and supplies are required for the
DuPonl/Oberlin  microfiltration technology.  Most  of these
services and supplies can be readily obtained.

    In case any of the pumps, mixers, or the air compressor
malfunctions,  or if any flow meters or pipelines crack, an
adequate on-site supply of spare parts or  access to a nearby
industrial supply center is an important consideration.

    An adequate supply of several materials is essential for
the DuPont/Oberlin microfiltration system. These materials
include (1) treatment chemicals (if needed), such as lime, to
                                                         12

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 adjust pH and precipitate metals, (2) filter aid/cake stabiliz-
 ing agent, such as ProFix, and (3) Tyvek® T-980 filter media.

    Laboratory facilities to perform analyses, such as metals
 and TSS in liquids, and TCLP test and moisture content in
 the filter cake, are required to monitor the treatment system's
 performance. If such facilities are not available on-site, it
 would be prudent to enter into a contract with a local analyti-
 cal laboratory for an ongoing monitoring program.

 Materials Handling Required by the Technology
    Materials handling requirements for the DuPont/Oberlin
 microfiltration technology would involve the handling of (1)
 pretreatment materials and (2) residuals. These are described
 below.

 Pretreatment Materials Handling
    Pretreatment materials  handling requirements for  the
 DuPont/Oberlin  technology  depend on the type of waste
 being treated. If the technology  is applied to  remove only
 paniculate matter, minimal  pretreatment  is required.  The
 pretreatment may involve addition of a filter aid to improve
 dewatering characteristics of the waste. However, if the tech-
 nology is applied to remove dissolved  metals, pretreatment
 generally involves metal precipitation (through  addition  of a
 hydroxide, carbonate, or sulfide source) and filter aid addi-
 tion. The pretreatment could become more extensive if (1)
 the metals need to be oxidized or reduced prior to precipitation
 or (2) any metal complexing agents present in  the waste
 require removal or destruction prior to metal precipitation.

    Even if no pretreatment is needed, the liquid wastes may
 need to be pumped to an  equalization  tank to reduce flow
 and contaminant concentration fluctuations. The installation
 of an equalization tank would also require additional plumb-
 ing connections.

 Residuals Handling
    Two major  types of residuals are generated from  the
 DuPont/Oberlin  microfiltration system:   (1) treated water
 (filtrate) and (2) filter cake.

    Filtrate could be disposed of either on- or off-site, once
 it meets the applicable regulatory requirements described at
 the end of this section.  Examples of on-site disposal options
 for the filtrate include groundwater recharge and  temporary
 storage on-site for sanitary use. Examples of off-site disposal
 options are discharge into  rivers, creeks, storm sewers,  and
 sanitary sewers. Bioassay tests may be  required in  addition
 to routine chemical and physical  analyses before the filtrate
 is  disposed. The pH of the filtrate  may  also need  to be
 adjusted prior to its  disposal depending on  (1)  the pH at
 which  metal precipitation is  done, (2) the filter aid added,
and (3) the disposal  site.  During the SITE demonstration,
the filtrate met the NPDES permit limits for disposal into a
local waterway for metals and TSS.  However,  it did  not
meet the  discharge limit for pH.  The treated water pH was
typically  11.5 while  the upper discharge limit was 9. The
filtrate pH was higher than the precipitation pH because of
the addition of ProFix (filter aid/cake stabilizing agent).

    The filter cake may be landfilled if it passes the paint
filter liquids test. Whether the filter cake can be disposed of
 at a nonhazardous landfill depends on its ability to meet the
 applicable regulations described in the "Regulatory Require-
 ments" section. During the SITE demonstration, the filter
 cake was disposed of as a nonhazardous waste. However, at
 the DuPont Electronics facility In Sun Valley, California, it
 is disposed of as a hazardous waste. DuPont plans to use
 ProFix instead of diatomaceous; earth  to eliminate off-site
 stabilization and reduce operating costs.

     The DuPont/Oberlin system also generates spent Tyvek®
 filter media, which requires disposal.   The spent Tyvek®
 media can  also  be disposed  of at either a hazardous or
 nonhazardous landfill, depending on whether it meets the
 applicable regulations.

 Personnel Requirements
     Since DuPont/Oberlin's microfiltration unit is automated,
 little operator attention is required; one operator per shift
 would be adequate. This person should be capable of (1)
 preparing pretreatment chemical slurries, such as lime and
 filter aid, and adjusting their flow rates to achieve the desired
 doses, (2) operating the pneumatic and electronic controls on
 the microfiltration unit, (3) collecting solids and liquid samples
 and performing simple physical/chemical analyses and mea-
 surements (for example, measuring pH, temperature, flow
 rate, and TSS), and (4) troubleshooting minor operational
 problems.  Analytical work  requiring higher skills (for ex-
 ample, performing metals analysis and the TCLP test) can be
 performed by a local laboratory.

    Each operator also should have an OSHA-required, ini-
 tial 40-hour health and safety training and an annual 8-hour
 refresher course before operating DuPont/Oberlin's system at
 hazardous waste sites.

 Potential Community Exposures
    Contaminant  exposure  from the DuPont/Oberlin
 microfiltration system to the community is minimal.  When
 treating wastes containing volatile contaminants,  such as
 mercury, proper care should be taken to control the emissions
 from the metals precipitation tank. Other types of exposures
 include paniculate emissions from lime and filter aid han-
 dling and significant noise (estimated to be 80 to 90 decibels)
 from the air compressor.

Potential Regulatory Requirements
    This subsection discusses specific environmental regula-
 tions pertinent to the transport, treatment, storage, and dis-
posal of wastes generated during I he operation of the DuPont/
Oberlin microfiltration system. The regulations that apply to
a particular remediation activity will depend on the type of
remediation  site and the type of waste being treated.  Table
3-1 provides a summary  of regulations  discussed  in this
subsection.

Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA)
    CERCLA, as amended by the Superfund Amendments
and Reauthorization Act (SARA) of 1986, provides for fed-
eral authority to respond to releases of hazardous substances,
pollutants, or contaminants to air, water,  and land (Federal
Register, 1990a).  Section 121 (Cleanup Standards) of SARA
                                                        13

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Table 3-1.  Regulations Summary
Act
Applicability
Application To DuPont/Oberlin Microfiltration System
                                                                                                                   Citation
CERCLA      Superfund Sites
                             The Superfund Program authorizes and regulates the cleanup of environmental
                             contamination. Applies to all CERCLA site cleanups.
                                                                                                                   40 CFR Part 300
RCRA


SDWA
CWA


CAA
CERCLA and RCRA Sites
Water Discharges Water
Rcinjcction, and Sole
Source/Wellhead Water
Source!!
Discharges to Surface
Water Bodies

Ambient Air Quality
TSCA
Other
               PCB Contamination
               Radioactive Wastes
AEAand
RCRA
Mixed Wastes
RCRA defines and regulates the treatment, storage, and disposal of hazardous
wastes.

Maximum contaminant levels and contaminant level goals would be appropriate
standards to consider in setting water cleanup levels at RCRA corrective
action and CERCLA response action sites. (Water cleanup levels are also
discussed under RCRA and CERCLA.) Reinjection of treated water would be
subject to underground injection control program and sole-source and
wellhead water sources to their respective control programs.

NPDES requirements of CWA would apply to both CERCLA and RCRA sites
where treated water is! discharged to surface water bodies.
                                                                                                                    40 CFR Parts 260-270
                                                                                                     40 CFR Part 141
CAA emission standards might apply to fugitive air emissions, if any,
from the DuPont/Oberlin microfiltration system (if the contaminant source and
treatment technology are sufficiently similar to a source and technology
regulated by the CAA). RCRA and CERCLA air emission requirements and any
state programs will be the primary air requirements for use of the DuPont/Oberlin
technology at CERCLA or RCRA sites.

TSCA regulates PCB jspill cleanups. If PCB-containing wastes are treated, TSCA
requirements will generally be appropriate in determining cleanup standards and
disposal requirements,

Agencies regulating the treatment, storage, and disposal of radioactive wastes
include: (1) the EPA, (2) the NRC, (3) the DOE, and (4) the states. Decisions
regarding appropriate'regulations should be based on: (1) the type of radioactive
constituents present and how they were generated; (2) the jurisdiction a site
is under; and (3) requirements that are most protective and appropriate for given
site conditions.
AEA and RCRA requirements apply to the treatment, storage, and disposal of
wastes containing both hazardous and radioactive components. OSWER and DOE
directives provide guidance for addressing mixed wastes.
                                                                                                                    40 CFR Parts 122-125
40 CFR Parts 50,
60, and 61
                                                                                                                    40 CFR Part 761
                                                                                                     40 CFR Parts 141,440
                                                                                                     (water); 10 CFR Parts
                                                                                                     20,30, 40, 61,70 (air
                                                                                                     and water discharges,
                                                                                                     treatment and
                                                                                                     disposal,  exposure
                                                                                                     limits);
                                                                                                     40 CFR Part 190
                                                                                                     (radiation doses);
                                                                                                     40 CFR Part 192
                                                                                                     (radon releases,
                                                                                                     cleanup standards);
                                                                                                     AEA(NRC licensees);
                                                                                                     DOE Orders

                                                                                                     AEA and RCRA
OSHA
All Remedial Actions
OSHA regulates on-site construction activities and the health and safety of
workers at hazardous waste sites. Implementation and operation of the
DuPont/Oberlin microfiltration system at CERCLA or RCRA sites must
meet OSHA requirements.
29 CFR Parts
1900-1926
29 CFR Part 1910.120
(hazardous waste
operations and
emergency response)
Note: Abbreviations included above are spelled out in this subsection's text
                                                                    14

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requires that selected remedies be protective of human health
and the environment and be cost-effective.  SARA states a
preference for remedies that are highly reliable, provide long-
term protection, and employ  treatment that permanently and
significantly reduces the volume,  toxicity, or mobility  of
hazardous  substances,  pollutants,  or contaminants.  The
DuPont/Oberlin microfiltration technology is one such  rem-
edy.  Section 121 also requires that  remedies selected  at
Superfund sites comply with federal and state applicable  or
relevant and appropriate requirements (ARAR), and it provides
only six conditions under which  ARARs for a remedial
action may be waived:  (1) the action is an interim measure
and the ARAR will be met at completion, (2) compliance with
the ARAR would pose  a greater risk  to health and the
environment than noncompliance, (3) it is technically im-
practicable to  meet  the ARAR, (4)  the standard of perfor-
mance of an ARAR can be met by an equivalent method, (5)
a state standard has not been consistently applied elsewhere,
and  (6) ARAR compliance would  not  provide a balance
between the protection achieved at a particular site and de-
mands on the Superfund for other sites.  These waiver options
apply only to Superfund actions taken  on-site, and justifica-
tion for the waiver must be clearly demonstrated (U.S. EPA,
1988).

    Generally, contaminated  water  treatment  using the
DuPont/Oberlin microfiltration system will take place on-
site, while treated water discharge,  filter cake disposal, and
filter media disposal may take place either on-site or off-site.
On-site  and off-site actions  must meet the substantive re-
quirements (for example, emission standards) of all ARARs;
off-site  actions must also meet  permitting and any other
administrative requirements of environmental regulations.

Resource Conservation and Recovery Act (RCRA)
    RCRA regulations define hazardous wastes and regulate
their transport, treatment, storage, and disposal. Wastes de-
fined as hazardous under RCRA include characteristic and
listed wastes.

    Criteria for identifying characteristic hazardous wastes
are included in 40 CFR Part 261 Subpart C. Listed wastes
from non-specific and specific industrial sources, off-specifi-
cation products, spill cleanups, and other industrial sources
are itemized  in 40  CFR Part  261  Subpart D.  For  RCRA
regulations to apply,  evidence  (for  example, manifests,
records, and knowledge of processes) must affirm that the
waste is hazardous. Site managers may also test the waste or
use their knowledge of  its  properties to determine if the
waste is hazardous.

    Contaminated water to be treated by the DuPont/Oberlin
microfiltration system will probably be hazardous or suffi-
ciently similar to hazardous  waste so  that RCRA standards
will be requirements. Because the  DuPont/Oberlin
microfiltration system  includes waste storage  in tanks, 40
CFR Part 265 standards for tank storage (Subpart J) should
be met.  Also, RCRA treatment requirements must be met.

    Filter cake and spent filter media generated during treat-
ment must be stored and disposed of properly.  If the water
treated is a listed waste, treatment  residues will be consid-
ered listed wastes (unless RCRA delisting requirements are
met).  If the treatment residues are not listed wastes, they
should be tested to determine if they are RCRA characteristic
hazardous wastes. Treatment residues  should also be tested
using EPA Method 9095 (paint filter  liquids test) to deter-
mine if they contain free liquids. Wastes containing no free
liquids are excluded from various leak  detection and second-
ary containment requirements for disposal.   Usually, the
DuPont/Oberlin treatment residues will not contain free liq-
uids.  If the residuals are not hazardous  and do not contain
free liquids, they can be disposed of at a nonhazardous waste
landfill.  If the filter cake or filter media is hazardous, the
following RCRA standards apply.

    40 CFR Part  262 details istandards for  generators  of
hazardous waste.  These requirements include obtaining  an
EPA  identification number,  meeting waste  accumulation
standards, labeling wastes, and keeping appropriate records.
Part 262 allows generators to store wastes up to 90 days
without a permit and without  having interim status as a
treatment, storage, and disposal facility. If treatment residues
are stored on-site for 90 days or more, 40 CFR Part 265
requirements apply.

    Any facility (on-site  or  off-site) designated for perma-
nent disposal of hazardous wastes must be in compliance
with RCRA.  Disposal facilities must fulfill permitting, stor-
age, maintenance, and closure r<;quirements  contained in  40
CFR Parts  264 through 270.  In addition, any authorized
state RCRA requirements must be fulfilled.   If treatment
residues are disposed off-site, 40 CFR Part 263 transporta-
tion standards apply.

    For both CERCLA actions and RCRA corrective ac-
tions, the treatment residuals generated by  the DuPont/Oberlin
microfiltration system will be subject to land disposal restric-
tions (LDR) if they are hazardous and land disposed (U.S.
EPA, 1989a). Several LDR compliance alternatives exist for
disposing of the filter cake and spent filter media if they are
hazardous:  (1) comply with the LDR that  is in effect, (2)
comply with the LDRs by choosing one of the LDR compli-
ance alternatives (for example, itreatability variance, no mi-
gration petition), or (3) invoke am ARAR waiver (this option
would only apply to on-site CERCLA disposal).

    40 CFR Part 264, Subparts F (promulgated) and S (pro-
posed) include requirements for  corrective action at RCRA-
regulated facilities.  In  addition, these  subparts generally
apply to remediation at Superfund sites.  Subparts F and S
include requirements for initiating and  conducting RCRA
corrective actions, remediating  groundwater,  and ensuring
that corrective  actions comply with  other environmental
regulations.  Subpart S also  details conditions under which
particular RCRA requirements may be waived for temporary
treatment units operating at connective action sites (Federal
Register, 1990b).

Clean Water Act (CWA)
    The NPDES permitting  program established  under the
CWA issues, monitors, and enforces permits for direct dis-
charges to surface  water bodies. Discharges to off-site re-
ceiving waters or to publicly owned treatment works (POTW)
must comply with applicable federal, state, and local admin-
istrative and substantive requirements.  Effluent  limits are
                                                        15

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contained in the NPDES permit issued for direct discharges
to off-site receiving waters.  No NPDES permits are issued
for on-site discharges or off-site discharges to POTWs, but
all substantive requirements (such as discharge limits) should
be identified and achieved.

Safe Drinking Water Act (SDWA)
    The SDWA, as amended in 1986, includes the following
programs:  (1) drinking  water standards, (2) underground
injection control (UIQ program, and (3) sole-source aquifer
and wellhead protection programs.                     ,

    SDWA drinking water primary (health-based) and sec-
ondary (aesthetic) maximum contaminant levels will gener-
ally  be  appropriate cleanup standards for water that is, or
may be, used as a source of drinking water.  In some cases,
alternate concentration limits  will be appropriate  (for ex-
ample, in cases where multiple contaminants are present).
Decision makers should refer to CERCLA and RCRA stan-
dards for guidance in establishing alternate concentration
limits.

    Water  discharge through injection  wells  is regulated
under the UIC program.  This program categorizes injection
wells as Classes I through V, depending on their construction
and  use.  Reinjection of treated water involves Class IV
(reinjection) or Class V (recharge) wells and should meet {the
appropriate requirements for well construction, operation,
and closure.

    The sole-source aquifer protection and wellhead protec-
tion programs are designed to protect specific drinking water
supply sources. If such a source is to be remediated, appro-
priate program officials should be notified, and any potential
problems should be identified before treatment begins.

Clean Air Act (CAA)
     Pursuant to the CAA, EPA has set national ambient air
quality  and pollutant emissions standards.  CAA  require-
ments will generally not apply  to  the DuPont/Oberlin
microfiltration system, although they may apply on a source-
specific basis (see radioactive waste regulations  discussion).
However, air emissions should be monitored to ensure that
they comply with CAA standards.

    RCRA air standards generally must be met for CERCLA
response actions and RCRA corrective actions. Forthcorning
RCRA regulations (40 CFR Part 269) will address air emis-
sions from hazardous waste treatment, storage, and disposal
facilities. When promulgated, these requirements will include
air emission standards for equipment leaks and process vents,
a category that will cover any fugitive air emissions frohi a
DuPont/Oberlin microfiltration system.  In addition, states'
programs to regulate toxic air pollutants, when established,
will be the most significant regulations for environmental
remediation activities.  Generally, air emissions  from i the
DuPont/Oberlin microfiltration system will be minimal, and
complying with air emission regulations should not be a
problem. To minimize air emissions, however, pretreatment
might be required for water containing volatile organic con-
taminants.
Toxic Substances Control Act (TSCA)
    The DuPont/Oberlin microfiltration system has the capa-
bility to handle wastes containing polychlorinated biphenyls
(PCB), although PCBs are not removed by the system. TSCA
requirements set standards for PCB spill cleanups and PCB
disposal which should be achieved if PCB waste is treated.
The EPA document CERCLA Compliance with Other Laws
Manual, Part II:  Clean Air Act and Other Environmental
Statutes and State Requirements discusses TSCA as it per-
tains to Superfund actions (U.S. EPA, 1989b). The proposed
RCRA corrective action regulations  (Federal Register, July
1990) state that PCB  waste should be handled in accordance
with TSCA PCB spill cleanup policy.  As TSCA does not
regulate direct spills to  surface water or  drinking water,
cleanup standards  for these sites are established by EPA
regional offices.

Radioactive Waste Regulations
    The DuPont/Oberlin microfiltration system has the capa-
bility to treat water contaminated with radioactive materials.
Decisions concerning what is an appropriate requirement for
a site contaminated with radioactive waste should be based
on the following factors:   (1) what type of radioactive con-
stituents are present and how they contaminate the site, (2)
whose regulatory jurisdiction the site falls under,  and (3)
which  regulation is  most protective or appropriate.  The
primary agencies that regulate the cleanup of radioactively
contaminated sites are EPA, the Nuclear Regulatory Com-
mission (NRC),  the Department of Energy  (DOE), and the
states.   In addition,  nongovernmental agencies may issue
advisories or guidance, which should also be considered in
developing a protective remedy.

    The SDWA has established maximum contaminant lev-
els for radionuclides in community water as a concentration
limit for alpha-emitting radionuclides and as an annual dose
limit for the ingestion of beta/gamma-emitting radionuclides.
These  standards are appropriate in setting cleanup standards
for radioactively contaminated water.  Discharge of treated
water from radioactively contaminated sites could be subject
to 40 CFR Part 440 Subpart C, which establishes radionuclide
concentration  limits  for liquid effluent from facilities that
extract and process uranium, radium, and  vanadium ores.
The  DuPont/Oberlin microfiltration system has  the potential
to treat water to well within the radioactivity limits established
by these regulations. However, treated water should be tested
to ensure that such limits are not being exceeded.

     Any fugitive radioactive air emissions  that result from
the DuPont/Oberlin microfiltration system must achieve ra-
dionuclide emissions standards promulgated under the CAA
(codified in 40 CFR Part 61).

     The Environmental Radiation Protection Standards (40
CFR Part  190) promulgated under the authority of the Atomic
Energy Act (AEA) set standards for radiation  doses to the
general public caused by normal operations within the uranium
fuel  cycle. These requirements should be considered at sites
where such contamination is being treated or disposed.
Standards regulating  the  stabilization, control,  and disposal
of uranium and thorium mill tailings are included in 40 CFR
Part 192.  These regulations set cleanup, control, and release
                                                        16

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standards for radioactive materials.

    NRC regulations cover the possession and use of source,
by-product, and special nuclear materials by NRC licensees.
These regulations apply to sites where radioactive contami-
nation exists.  10 CFR Parts 20, 30, 40, 61, and 70 cover
protection of workers and the public from radiation, dis-
charges of radionuclides to air and water, and waste treat-
ment and disposal requirements for radioactive waste.  The
filter cake and spent filter media generated by microfiltration
of radioactive water might be regulated under these parts if
they contain residual radioactivity.

    DOE  requirements are included in a series of internal
DOE orders that have the same force as regulations at DOE
facilities.  These DOE directives should be considered when
developing protective remedies at CERCLA sites or RCRA
corrective action sites, although they apply directly only to
DOE sites.  DOE orders  address exposure limits for  the
public, concentrations of residual radioactivity in soil and
water, and management of radioactive wastes  (U.S. DOE,
1988).

Mixed Waste Regulations
    Use of the DuPont/Oberlin microfiltration system at sites
with radioactive  contamination might involve the treatment
or generation of mixed waste. Mixed waste contains both
radioactive and hazardous components (as  defined by  the
AEA and RCRA) and is subject to the requirements of both
acts. When the  application of both regulations results in a
situation that is inconsistent with  the AEA (for example, an
increased likelihood of radioactive exposure), AEA require-
ments supersede RCRA requirements.

    EPA's Office of Solid Waste and Emergency Response
(OSWER), in conjunction with the NRC, has issued several
directives to assist in the identification, treatment, and dis-
posal of low-level radioactive mixed waste. Various OSWER
directives include guidance on defining, identifying, and dis-
posing of commercial mixed low-level radioactive and haz-
ardous waste (U.S.  EPA,  1987).   If the DuPont/Oberlin
microfiltration system is used to ireat low-level mixed wastes,
these directives should be considered.  If high-level mixed
waste or transuranic  mixed waste is treated, DOE internal
orders  should be considered when  developing  a protective
remedy (U.S. DOE, 1988).

Occupational Safety and Healtlli Act (OSHA)
    CERCLA response actions and RCRA corrective actions
must be performed in accordance with OSHA requirements
detailed in 29 CFR Parts 1900 through  1926, especially Part
1910.120, which provides for the health and safety of work-
ers at hazardous waste sites. Ora-site construction activities
at Superfund or RCRA corrective action sites must be per-
formed in accordance with Part 1926 of OSHA (Safety and
Health  Regulations for Construction).   For example, con-
struction of electric utility hookups for the DuPont/Oberlin
microfiltration system would need to comply with Part 1926,
Subpart K  (Electrical).  Also, any  more stringent state  re-
quirements  would need to be met.
                                                       17

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                                                   Section 4
                                            Economic Analysis
    The  costs associated  with  the DuPont/Oberlin
microfiltration technology have been placed into the 12 cost
categories that are applicable to typical cleanup activities at
Superfund and Resource Conservation  and Recovery Act
(RCRA) corrective action sites (Evans,  1990). These cost
categories are defined and discussed in  this  section as they
apply  to  the DuPont/Oberlin microfiltration technology,
thereby forming the basis for the estimated costs presented in
Table 4-1. The annual operating and maintenance costs, as
well as one-time costs presented in Table 4-1, are for two
microfiltration systems with filtration areas of 2.4 square feet
(demonstration  unit) and 36 square feet (largest unit avail-
able). The costs presented in this analysis are order-of-magni-
tude (-30 to +50 percent) estimates, as defined by the Ameri-
can Association of Cost Engineers (Humphreys, 1984).

Site-Specific Factors Affecting Cost
    A number of factors affect the estimated cost of a DuPont/
Oberlin microfiltration system. These factors are highly site-
specific and rather difficult to identify if accurate site loca-
tion and site data are unavailable. The factors that will affect
the cost generally include: volume of groundwater or other
type of liquid waste to be treated; type and concentration of
contaminants in the water; physical site  conditions (such as
site access and availability of utilities); required support fa-
cilities, extraction wells for contaminated groundwater, auxil-
iary equipment, and buildings; geographical  location (avail-
ability of supplies and consumables, availability of service
for equipment); treatment goals to be met; discharge permit
requirements; and frequency of equipment  repair and  re-
placement.

Basis of Economic Analysis
    The DuPont/Oberlin  technology can be applied to treat
several types of  liquid wastes  including contaminated
groundwater, landfill leachate, and industrial wastewater. For
the purpose of this economic analysis, contaminated ground-
water was selected as the liquid waste since it represents (1) a
waste commonly found at Superfund and RCRA corrective
action sites and (2) a waste treatment scenario that covers
several cost categories. It should be noted that all the catego-
ries for the contaminated groundwater scenario may not ap-
ply to other types of liquid waste. Therefore, when estimating
the costs  for a given scenario, only applicable categories
should be used.

    For the purpose of this economic analysis, it is assumed
that a DuPont/Oberlin microfiltration system will treat con-
taminated groundwater on a batch cycle, 24 hours per day, 7
days per week for 1 year.  The average time of  each cycle is
assumed to be 20 minutes. The ratal volume of groundwater
treated  during each  cycle is difficult  to estimate since it
depends on the (1)  concentration of the contaminants of
concern in the groundwater, (2) amount of filter aid used,
and (3) size of the microfiltration unit  During the technol-
ogy  demonstration,  a  2.4-square foot microfiltration unit
treated approximately 20 gallons of groundwater during each
cycle.  Therefore,  it is assumed that  the  36-square foot
microfiltration unit will be capable of treating 300 gallons of
groundwater during each cycle.

    During a 1-year period, the 2.4-square foot unit will treat
approximately 525,600 gallons, and the 36-square foot unit
will treat approximately 7,884,0()0 gallons.  A 1-year period
of time was chosen  for this analysis so that an  estimated
annual operation and maintenance cost  could be developed.
It should be noted, however, that most groundwater remedial
actions cover a significantly longer period of time (such as
10 to 30 years) and may require multiple treatment units.

    For this analysis, the following assumptions were made
regarding the untreated groundwater, operating conditions,
and filtrate.  The groundwater is acidic (has a pH of less than
7), has negligible ligands and organic contaminants, and is
primarily contaminated with heavy metals (such  as lead or
zinc) at levels of up to 500 mg/L. The microfiltration system
operating conditions are as follows:  a precipitation pH of 9
(a lime dose of 1.5 g/L to raise the pH from  4.7); a filter aid
dose of  12  g/L; a blowdown time  of 0.5 minute; and a
blowdown pressure of 38 psig. The contaminated groundwa-
ter will be  treated to  meet National  Pollutant  Discharge
Elimination System (NPDES) requirements for discharge into
a nearby surface water.

    The following is  a list of other assumptions used for this
analysis:

        The site is located in the Midwest.
        Utilities such as electricity and telephone lines
        will be overhead.
        Suitable access roads are available.
        Contaminated groundv/ater is in  a  shallow
        aquifer.
        A heated temporary tent-like enclosure will be
        required to house equipment.
        The installation cost of the microfiltration system
        at the site is assumed to be 3 to 5 percent of the
        capital equipment cost (depending on size) and
        is included in the capital cost.
        One technician will be: required per  shift to
        operate and maintain the equipment, collect all
        required samples,  and  perform  equipment
        maintenance and minor repairs.
                                                        19

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Table 4-1. Estimated Costs Associated with DuPont/Oberlin Microfiltration Systems
Cost Categories
                                                     Estimated Costs (1990 $)
                                                      2.4 sq. ft."   36 sq.ft.8
Site Preparation b
Permitting and Regulatoryb
Capital Equipment11
Startup and Fixed b
Labor6
Supply and Consumable0
Utility °
Effluent Monitoring0
Residuals and Waste Shipping, Handling, and
Transporting0
Analytical0
Equipment Repair and Replacement c
Site Demobilization15
209,200
2,300
47,800
80,000
133,400
16,900
5,500
15,000
3,700
36,000
2,500
30,000
843,200
11,200
231,800
80,000
133,400
220,000
82,500
15,000
55,200
36,000
7,000
85,000
  Total One-Time Costs

  Total Annual Operation and Maintenance Costs
                                                       369,300  1,251,200

                                                       213,000   549,100
 Notes:
During a one-year period, it is assumed that the 2.4-sq. ft. unit will treat
aboutS25,600 gallons and the 36-sq. ft. unit will treat about 7,884,000
gallons.
One-time costs.
Annual operation and maintenance costs.
          Labor costs associated with major equipment
          repairs or replacement are not included.
          The filter cake and used filter  media will be
          considered nonhazardous wastes, and will be
          disposed of in a permitted sanitary landfill.
          A composite sample will be taken weekly from
          the filtrate discharge and analyzed for  heavy
          metals and pH.
          Filter aid will  be purchased in sacks for the
          2.4-square foot unit and in bulk for the 36-
          square foot unit.
          No pretreatment other than lime addition and
          filter aid addition is required.
          The filtrate will require pH adjustment (post-
          treatment)  to meet applicable discharge limits
          (typically 6 to 9).
          Site  demobilization  does   not   include
          transportation of the microfiltration equipment.
                                               A discussion of each of the 12 cost categories and the
                                           elements  associated  with  each category  is  provided in
                                           Table 4-1.

                                           Site Preparation Costs
                                               The costs associated with site preparation include plan-
                                           ning and  management, system design (as well as design of
                                           auxiliary systems and controls), legal searches, access rights,
                                           construction work, emergency and safety equipment, shake-
                                           down, and start-up.

                                               Site preparation costs will vary depending on the type,
                                           condition, and geographical location of the site.  Sites that
                                           require major clearing or sites that are located in the northern
                                           part of the country  will have significantly increased site
                                           preparation cost. Utilities must be  installed in accordance
                                           with national codes and local ordinances.
                                                           20

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    In addition  to  the above items,  site preparation costs
include an untreated groundwater storage tank,  an office/
laboratory trailer, an air compressor, a temporary tent-like
structure for the microfiltration  system,  a pH adjustment
system, and treated groundwater discharge piping.

    For this analysis, site preparation costs are estimated to
be  approximately  $209,200  for  the  2.4-square  foot
microfiltration unit  and $843,200  for  the 36-square foot
microfiltration unit (R.S. Means Co. Inc., 1989; McArdle, et
al, 1988). Installation of a groundwater extraction and trans-
mission system, which was not included in this analysis, may
considerably increase the site preparation cost.  The cost for
this system was  not estimated because it is highly site-spe-
cific.

Permitting and Regulatory Costs
    Permitting and  regulatory costs will vary depending on
whether treatment is performed on a Superfund or a RCRA
corrective action site and on how the effluent, filter cake, and
filtrate are disposed.  Section 121 (d) of the Comprehensive
Environmental Response, Compensation, and  Liability Act
(CERCLA), as amended by the Superfund Amendments and
Reauthorization Act (SARA), requires that remedial  actions
be consistent with  applicable  or relevant and appropriate
requirements  (ARAR) of environmental laws, ordinances,
regulations, and  statutes.  ARARs include federal standards
and criteria, as well as  more stringent standards  or  criteria
promulgated under state  or local jurisdictions, and must be
determined on a site-specific basis.

    At  RCRA corrective action  sites, analytical protocols
and annual monitoring records will have to be kept, which
will increase the regulatory costs. For these situations, an
additional 5 percent should be added to the cost estimated for
this category. Contaminated soil removed during the installa-
tion of monitoring and extraction wells will have to be disposed
of in compliance with RCRA or state requirements. Soil that
will be disposed of at a permitted landfill will have to meet
federal or state land disposal restriction requirements.

    Permitting and regulatory costs are assumed to be ap-
proximately 5 percent of the capital equipment costs for a
treatment operation  that is  part  of  a Superfund remedial
action.

Capital Equipment Costs
    Capital equipment  costs  include the  cost of the
microfiltration system and the required auxiliary equipment,
as well as the installation cost. Based on information pro-
vided by Oberlin, these costs are $45,500 for the 2.4-square
foot unit and $225,000 for the 36-square foot unit. Installa-
tion costs are assumed to be approximately 3 to 5 percent of
the capital cost (depending on size).  The total capital cost is,
therefore, estimated to be $47,800 for the 2.4-square foot unit
and $231,800 for the 36-square foot unit. These costs include
only the equipment furnished  by the microfiltration  system
manufacturer.
Startup and Fixed Costs
     Startup costs  include those costs required to establish
operating procedures, train operators, perform initial shake-
down of equipment and analysis procedures, and initiate an
environmental monitoring program.

     To ensure safe, economical,  and efficient operation of
the system, an operator  training program will be required.
The costs associated with developing the operator training
program will include developing a health and safety program
and associated documents, providing health and safety train-
ing, and providing operation and maintenance training for
the microfiltration system.

     All new operators will need health and safety training.
In addition, since all operators  will be responsible for daily
monitoring and operation of the  equipment, operation and
maintenance training will be required and will be provided
by equipment manufacturers and the engineer responsible for
designing the system. Startup training costs are estimated to
be approximately $30,000.  This estimate is based on four
40-hour health and safety training courses, 4 weeks of opera-
tion and maintenance training  (including "hands-on"), and
one week follow-up training for equipment troubleshooting.

    Mobilization and shakedown  costs include  transporta-
tion of the equipment to  the site, initial  setup, initial startup
and trial runs, and equipment optimization.  These costs are
site-specific and will  vary depending on the location of the
site, complexity of controls, and the degree of automation.
For this analysis, mobilization, shakedown, and equipment
startup are assumed to be $50,000. Total startup and fixed
costs are estimated to be approximately $80,000.

Labor Costs
    After the construction, equipment installation, initial
startup, and optimization are completed, the operators will
assume operation of the system. The system will operate on a
batch cycle,  with  an operator  monitoring operation of all
auxiliary equipment and making necessary adjustments to
compensate for changes in metal  concentration,  pH, and
temperature of the groundwater.   The operator will  also
prepare the required chemicals, such as lime slurry for pH
adjustment and filter aid, and will collect the required samples,
dispose of filter cake, and operate auxiliary equipment. This
analysis assumes that four operators will operate this system
on a shift basis 7 days per  week, 24 hours per day.   It is
assumed that the operators will  Ije paid $15 per hour (fringe
benefits are not included). The annual operating labor cost
will be $131,400 for the operators.  All operators will require
an annual health and safety  refresher course, which is esti-
mated to cost $2,000 annually.  Total annual labor costs are
estimated to be $133,400.

Supply and Consumable Costs
    Supplies and consumable costs for  the DuPont/Oberlin
microfiltration system include filter aid, lime for pH control,
filter media,  hydrochloric acid  for effluent pH adjustment,
and other miscellaneous  supplies.   The quantities of filter
aid, lime, filter media, and hydrochloric acid used will de-
pend on the size of the system and the concentrations of the
metallic contaminants in  the groundwater.  These costs are
                                                        21

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estimated to be approximately $16,900 for the 2.4-square
foot unit and $220,000 for the 36-square foot unit. Except
for hydrochloric acid, costs are based on the average cost of
supplies and consumables incurred during the SITE demon-
stration of the  DuPont/Oberlin system.  Hydrochloric acid
costs are estimated based on lowering the filtrate (effluent)
pH from 11.5 to between 6 and 9.

Utility Costs
    The DuPont/Oberlin system operates on 240/480V three-
phase electric power.  In addition  to electric power, the
system requires high pressure air at approximately  100 psig.
Since the air compressor is driven by an electric motor, only
total electric power requirements  will be  evaluated.  The
system also requires potable water at 40 psig for equipment
washing and preparation of lime and filter aid slurries. About
150  gallons of potable water should be adequate per 1,000
gallons of water treated.   In some applications, to conserve
water filtrate may be used instead of potable water.

    The total electric power requirements will greatly de-
pend on the total quantity of groundwater treated as well; as
the size of the microfiltration unit used, the size of the
compressor used, and the size of all  auxiliary equipment,
which is also electrically driven.  It  is estimated  that the
electric power cost will be approximately  $8.46 per 1,000
gallons treated. For this  analysis,  it is assumed  that the
power cost is $.10 per kilowatt-hour. It should be noted that
the cost of power can vary  by as much as 50  percent,
depending on the local utility company rates.

    The cost of water required is estimated to be about $2,00
per 1,000 gallons treated.  It should be noted that this cost
can vary by as much as  1,000 percent depending on  geo-
graphic location, availability of water, distance to the nearest
water main, and other factors.  If water is to be delivered by
truck, this cost will be higher yet.

    The cost of heating and ventilation of the required tent-
like  enclosure for the microfiltration equipment and office/
laboratory space is  not included in this analysis.  This cost
will  greatly depend on geographic location, availability of
natural gas (cost of electric heat is much higher), and many
other factors.

Effluent Monitoring Costs
    This cost category covers effluent monitoring for com-
pliance with NPDES permit limits. Effluent monitoring will
be performed by the microfiltration system operators. Efflu-
ent will be discharged to a nearby surface water or reinjected
into  the groundwater if permitted by local and state regula-
tions. The cost estimate for effluent monitoring will greatly
depend on local and state requirements. For this analysis, it
is assumed that the effluent will be  discharged to a nearby
surface water by gravity, and the cost associated with moni-
toring is $15,000 per year.

Residuals  and  Waste  Shipping,  Handling,  and
Transportation Costs
    The DuPont/Oberlin  microfiltration system  produces
considerable amount of filter cake, which requires special
handling and disposal.  Used filter media also needs to be
disposed of. For this analysis, all these materials are assumed
to be nonhazardous and, therefore, may be disposed of in a
permitted sanitary landfill.  These costs will depend on geo-
graphic location, distance to the permitted landfill from the
site, as well as other factors such as the concentrations of
regulated metallic contaminants in the groundwater, the de-
gree of treatment, and the quantity of filter aid used.

    Waste  shipping, handling, and transportation costs are
based on the generation of 70 pounds of filter cake per 1,000
gallons of groundwater treated and an estimated disposal cost
of $200 per ton. The annual handling,  shipping, and disposal
costs are estimated to be $3,700 for the 2.4-square foot unit
and $55,200 for the 36-square foot unit.

Analytical  Costs
    Analytical  costs  include  sample shipment, laboratory
analysis, data reduction and tabulation, quality assurance and
quality control (QA/QC), and reporting.  Monthly laboratory
analysis  costs are estimated to be approximately $2,000,
while data  reduction and tabulation, QA/QC, and reporting
should cost approximately $1,000 per month. This analysis
assumes that four treated water samples will be taken every
month  and analyzed for metals.  Total estimated  analytical
costs, therefore, are approximately $36,000 per year.

Equipment Repair and Replacement Costs
    During the course of operation, some parts of the system
may require repair or replacement Since insufficient data is
available on  the  long-term reliability of a microfiltration
system, no cost can  be assigned. For this analysis, it  is
assumed that the  annual equipment repair and replacement
cost is $2,500  for the 2.4-square foot microfiltration unit
system and $7,000 for the 36-square foot unit system. This
cost, however, does not include any major repairs or replace-
ments.

Site Demobilization Costs
    Site demobilization will include operation shutdown and
decommissioning of equipment, site cleanup and restoration,
disconnection of utilities, closing  of groundwater extraction
wells,  and  disposal of decontamination waste and any other
wastes.  Site demobilization  costs will vary depending on
whether the treatment operation was conducted at a Superfund
site or  at a RCRA corrective action site.  Demobilization at a
RCRA corrective action site will require  detailed closure
plans and permits, which are not required at a Superfund site.
This analysis assumes site demobilization costs  will only
cover costs of disassembling  and  transporting all equipment
and removing all exposed piping and electrical lines. This
estimated cost  is based on previous  similar projects. The
estimated demobilization cost for  the 2.4-square foot unit is
$30,000 and $85,000 for the 36-square foot unit. Decommis-
sioning and disposal of buildings, permanent tanks, and ex-
traction/monitoring  wells is not included  in  this  cost esti-
mate.
                                                         22

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                                              References
Evans, G., 1990. Estimating Innovative Technology Costs
    for the SITE Program, Journal of Air andWaste Man-
    agement Association, 40:7 1047-
    1051.

Federal Register, 1990a. National Oil and  Hazardous
    Substances Contingency Plan; Final Rule, Volume 55,
    No. 46, March 8.

Federal Register, 1990b. Proposed Rules for Corrective
    Action for Solid Waste Management Units at Hazardous
    Waste Management Facilities, Volume 55, No. 145,
    My 27.

Humphreys, K.K.,  1984. Project and Cost  Engineers'
    Handbook, 2nd Edition. Marcel Dekker, New York, New
    York.

Karassik, I.J., 1986. Pump Handbook, 2nd Edition, McGraw-
    Hill Book Company, New York, New York.

McArdle, J.L., et al,  1988.   "Leachate Treatment Unit
    Processes- -Physical/Chemical Treatment Operations,
    Neutralization,"  Treatment of Hazardous Waste
    Leachate—Unit Operations and  Costs, Pollution
    Technology  Review No. 151, Noyes Data Corporation,
    Park Ridge, New Jersey.

Oberlin,  1984.  Oberlin  Pressure Filter Instruction  &
    Maintenance Manual, Oberlin  Filter  Company,
    Waukesha, Wisconsin.

R.S. Means Co. Inc., 1989. Means Construction Cost Data,
    47th  Annual Edition.   Construction Consultants and
    Publishers, Kingston, Massachusetts.
U.S. DOE, 1988. Radioactive Waste Management Order,
    DOE Order 5820.2A, September 26.

U.S. EPA, 1982. Process Design Manual for Dewatering
    Municipal Wastewater Sludges,   EPA/625/1-82/014,
    Cincinnati, Ohio.

U.S. EPA, 1987. Joint EPA/NRC Guidance on Mixed Low-
    Level Radioactive  and Hasiardous Waste:  OSWER
    Directives 9480.00-14, June 29; 9432.00-2, January 8;
    and 9487.00-8 August 3.

U.S. EPA, 1988.  CERCLA Compliance with Other Laws
    Manual (Interim Final), OSWER, EPA/540/G-89/006.

U.S. EPA, 1989a. Superfund LDR Guide #1, Overview of
    RCRA Land Disposal Restrictions (LDRs), U.S. EPA
    Directive 9346.3-01FS.

U.S. EPA, 1989b.  CERCLA Compliance with Other Laws
    Manual:  Part II. Clean Air Ac land Other Environmental
    Statutes and State Requirements, (Interim Final), OSWER
    Directive 9234.1-02.

WPCF, 1984. Prime Movers:  Engines, Motors, Turbines,
    Pumps, Blowers & Generators, Manual of Practice OM-
    5, Water Pollution Control Federation, Washington, D.C.
                                                    23

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                                                 Appendix A
                                 Vendor's Claims for the Technology
Introduction
    Many industries face the challenge of removing heavy
metals from groundwaters and industrial wastewaters to meet
stringent discharge or disposal limits. Conventional technolo-
gies, such as chemical precipitation followed by clarification
and sand filtration, are generally unsuitable to meet the strin-
gent limits, while advanced technologies such  as  ion  ex-
change, ultrafiltration,  and  reverse  osmosis  are expensive
options for heavy metal removal. The metals precipitate gen-
erated during  the chemical  precipitation  process is usually
landfilled.  However, the Resource Conservation  and Recov-
ery Act (RCRA) requires that the precipitate pass the paint
filter  liquids test before  it  can be  landfilled. RCRA  also
requires that the precipitate pass the toxicity characteristic
leaching  procedure (TCLP)  test  for  its disposal at  a
nonhazardous  waste landfill. For these reasons, the metals
precipitate must be adequately dewatered (to pass the paint
filter liquids test) and stabilized (to pass the TCLP test).

    The DuPont/Oberlin  microfiltration technology can treat
metal-bearing wastewaters to meet regulatory requirements at
a reasonable cost. The  use of this  technology  has  solved
many problems found in  the metal forming and metal work-
ing industries, eliminating many  disadvantages  of conven-
tional treatment technologies, particularly chemical precipi-
tation followed by clarification and sand filtration. A descrip-
tion of the DuPont/Oberlin microfiltration technology and its
applications are presented below.

DuPont/Oberlin Microfiltration Technology
    The DuPont/Oberlin microfiltration technology is  a
physical separation process for removing submicron particles
from liquid wastes. The submicron particles from liquid wastes
are removed using a  spunbonded  olefin filter media, known
as Tyvek® T-980 (developed by E.I. DuPont de Nemours and
Company, Inc.), and an automatic pressure filter  (developed
by Oberlin Filter Company). The  Tyvek® filter media has  a
high tensile  strength (wet and dry) and is manufactured and
sold in rolls, making it suitable for use with the Oberlin filter,
which  uses  a roll feed  and discharge. Another important
feature of the Tyvek® media is  its smooth and slick surface
which facilitates excellent separation of filtered solids from
its surface. Tyvek® can remove submicron particles at a cost
almost 97.5 percent less than  other competitive filtration
media, such as microporous membranes  (Lim and  Mayer,
1989).

    When liquid wastes  contain dissolved metals, DuPont/
Oberlin pretreats the wastes to convert the metals  into an
insoluble form (precipitate)  using  chemicals, such as lime,
caustic, sodium carbonate,  or sodium  sulfide.   After  the
metals are precipitated, a filter slid/stabilizing agent, known
as ProFix (manufactured by EnviroGuard, Inc. of Houston,
Texas),  is added  to  the metals precipitate prior  to
microfiltration to produce a dry and stabilized filter cake.

    A brief description of the  Oberlin pressure filter and its
capabilities are presented below.

Oberlin Pressure Filter Equipment
    The  Oberlin pressure filter is a versatile, rugged, and
industrial-scale solid/liquid separation unit.  A schematic  of
the Oberlin pressure filter is shown in Figure 2-1. The filter
has two compartments—an upper compartment, or filter
platen; and a lower compartment, or filter chamber. The
platen moves while the chamber is fixed in place. The filter
media lies between these two compartments.

    At the beginning of a filtration cycle, airbags lower the
filter  platen against the filter chamber.  Platen seals on the
perimeter of the compartments fomi a liquid-tight seal around
the filter media. The liquid waste containing solids is pumped
into the platen and forced by the pump pressure through the
filter  media. The filtered liquid is collected in  the lower
compartment and drained out.

    When  the pressure  inside  the  filter  reaches 30-50 psig
(maximum, depending  on  the model),  the feed pumping
stops, and pressurized air is fed into the platen forcing the
remaining liquid through the filter cake and media. After the
cake  is dried (as  determined  by  back pressure and time
elapsed), the platen is lifted by an  air cylinder. The cake is
then automatically  discharged  either  by using an endless
conveyor belt or by simply pulling the spent filter media by a
motor driven reroller.  After the cake discharge, the filter
platen automatically descends  zmd a new filtration cycle
starts.

    The filter is made of carbon steel.  All parts can be lined
with 304/316 stainless  steel or coated with Halar or other
metals such as Alloy 20, if required. The filter does not
require a special foundation; a flat area is adequate. Electri-
cal controls are based on either discrete relays and timers or
programmable logic controllers (PLC). Filters with explosion
proofing  option (for treating  munitions wastes) are also
available.

Oberlin Pressure Filter Capabilities
    The Oberlin pressure filter has  a few unique capabilities
to produce  a high  quality filtrate and a dry cake  while
treating liquid wastes. These capabilities are listed below:
                                                        25

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        It operates at a relatively high pressure (up to
        50 psig) to ensure long operating cycles.
    •   It is truly an automatic filtration system designed
        for unattended operation (except for filter aid
        slurry preparation, cake removal, and filter media
        roll replacement). Its operation is precisely
        controlled through a PLC to minimize operator
        attention.
        It  has a horizontal filtering area to allow
        relatively thick filter cake to  form.  Also, the
        cake formed in this process is dry because the
        moisture present in the cake  is  forced  out by
        pressurized air or nitrogen.
    •   The  filter  is  skid-mounted  for  easy
        transportation.
    •   The operating costs are kept  low through the
        use of standard industrial controls for the filter.

Applications of the DuPont/OberlinMicrofiltration
Technology
    The DuPont/Oberlin microfiltration technology has been
used to:

     •   Treat wastewater containing uranium, aluminum,
        lead, cadmium, nickel, copper, and zinc to meet
        fairly stringent National Pollutant Discharge
        Elimination System limits at metal forming
        operations in uranium manufacturing processes.
     •   Treat lead-bearing wastewaters from a ceramics
        manufacturing plant.
     •   Remove  heavy  metals  from  a  battery
        manufacturing facility's wastewater.
     •   Remove lead solids from  an  electronics
        manufacturing plant's wastewater.
        Remove  lead  from  a munitions  plant's
        wastewater.
     •   Remove copper, zinc, cadmium, and lead from
        another munitions plant's wastewater.
     •   Remove iron, lead, chromium, nickel, copper,
        and zinc from contaminated groundwater prior
        to volatile organic compounds  removal by
        stripping,                                 !
    •    Remove iron,  lead, chromium, copper,  zinc,
        silver,  and nickel from  a chemical  plant's
        wastewater prior to discharge. Discharge limits
        are very low for this application (for example,
        13 ppb for copper).


    Details on some of these applications can be found in a
paper presented at the Second U.S. EPA Forum on Innova-
tive Hazardous Waste Treatment Technologies, Philadelphia,
Pennsylvania (Mayer, 1990).  As  can be seen from  these
applications, the technology is well suited for a variety of
wastewaters  and groundwaters, if the metals can be con-
verted into an insoluble form prior to filtration.

Summary
    Over the past 8 years, the DuPont/Oberlin microfiltration
technology has evolved into a viable technique for removing
heavy metals from contaminated groundwaters and industrial
wastewaters. It is basically a  submicron  filtration process
that removes practically all suspended  metals  much  more
effectively than conventional techniques (such as precipitation
followed by clarification,  and  sand filtration).  It also pro-
duces a dry cake that will pass the paint filter liquids test and
the TCLP test. It accomplishes this in a simple, one-step
operation  that is totally automatic except for media replace-
ment, filter aid makeup, and cake removal. Systems are now
available that can also automate these steps, if desired.

References
Lim,  H.S., and E. Mayer,  1989.  Tyvek for Microfiltration
    Media, Fluid Particle Separation Journal, 2:1:17-21.
Mayer, E., 1990. DuPont/Oberlin Microfiltration System for
    Hazardous Wastewaters, presented at the Second U.S.
    EPA Forum on Innovative Hazardous Waste Treatment
    Technologies: Domestic and International, Philadelphia,
    Pennsylvania.
                                                        26

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                                                Appendix B
                                     SITE Demonstration Results
 Introduction
     In February 1988, E.I. DuPont de Nemours and Com-
 pany, Inc. (DuPont) and Oberlin Filter Company (Oberlin)
 submitted a joint proposal for their microfiltration technol-
 ogy to U.S. Environmental Protection Agency's (EPA) Of-
 fice of Research and  Development (ORD) and Office of
 Solid Waste and Emergency Response (OSWER) under the
 Superfund Innovative  Technology Evaluation (SITE) pro-
 gram. EPA selected the DuPonl/Oberlin microfiltration tech-
 nology and identified the Palmerton Zinc Superfund (PZS)
 site as an appropriate site for the technology demonstration.
 The technology was demonstrated at the PZS site  in April
 and May 1990 through a cooperative effort between ORD,
 OSWER, EPA Region  3, DuPont, and Oberlin. This appen-
 dix briefly describes the PZS site and summarizes the SITE
 demonstration activities and demonstration results.

 Site Description
    The  site  is  located  in  the Lehigh Valley along the
 Aquashicola Creek in the town of Palmerton, Pennsylvania.
 Figure B-l is a map of the site.  The site includes all areas of
 possible contamination  resulting from operations at the Zinc
 Corporation of America (ZCA) industrial complex. The ZCA
 complex  consists of two zinc smelting plants.  West of the
 town is  the West Plant, located  where the  Lehigh River
 meets the Aquashicola  Creek. The East Plant is located on
 the southern bank of the Aquashicola Creek.

    Zinc smelting operations at the PZS site began in 1898
 and 1915 at the West and East Plants, respectively. In 1980,
 primary zinc  smelting  at the ZCA facility ceased  and the
 West Plant was shut down.  Secondary  metal refining and
 processing operations continue in the East Plant.

    During the last 70 years, zinc smelter operations have
 resulted in 33 million tons of zinc residue accumulating and
 forming an extensive cinder bank along the southern bound-
 ary of the East Plant. This cinder bank has contaminated the
 surrounding areas,  including the  groundwater and surface
 water. Because of the  contamination, the cinder bank was
 placed on the National Priorities  List (NPL No. 339) in
 December 1982. Under an Administrative Order of Consent
 dated September 24, 1985, ZCA agreed to conduct a reme-
 dial investigation/feasibility study (Rl/FS) of the on-site sur-
 face water and groundwater, as well as the cinder bank.  The
 RI/FS work was carried out by ZCA's contractor, R.E. Wright
 Associates, Inc.

Site Contamination Characteristics
    Air emissions from smelting operations at the East and
 West Plants, and  the cinder bank,  have contaminated the
 surrounding environment.  The primary constituents of con-
 cern are cadmium, copper, lead, and zinc. Cadmium, copper,
 and lead commonly occur  as  minor constituents  in zinc
 sulfide ore, which was the primary raw material used in
 smelting operations at the Palmerton smelting plants.  Previ-
 ous studies as well as the RI/FS have shown heavy metals in
 measurable amounts in  soils in the surrounding Palmerton
 area, with the highest concentrations present in soils immedi-
 ately surrounding the East and West Plants. Emissions from
 the smelters  also caused the defoliation of  approximately
 2,000 acres on Blue Mountain.

     Data from the draft RI report (ZCA, 1987) was used to
 select the shallow aquifer at the site as the candidate waste
 stream  for  the  technology demonstration.  Groundwater
 samples collected by EPA in June 1989 indicated that the
 shallow groundwater is contaminated with high levels of zinc
 (400 to 500 mg/L) and  trace levels  of cadmium (1 mg/L),
 copper  (0.02 mg/L), lead (0.015 mg/L), and selenium (0.05
 mg/L).

 Review of SITE Demonstration
     The SITE demonstration was divided into three phases:
 (1) site preparation; (2)  technology demonstration; and (3)
 site demobilization. These activities and a review of technol-
 ogy and equipment performance  during  these phases are
 described below.

 Site Preparation
     Approximately 10,000 square feet of relatively flat ground
 surface  was used for the microfilttation system and support
 equipment and facilities, such a.s a filtrate  storage tank,
 nonhazardous and potentially hazardous waste storage con-
 tainers, office and field laboratory trailer, and a parking area.
 A temporary enclosure covering approximately one-third of
 the demonstration area was erected to provide shelter for the
 microfiltration system during inclement weather. A second-
 ary containment  area was provided  for the tanks  holding
 treated and untreated groundwater to collect  any spills or
 leakage.  Site preparation included setting up major support
 equipment, on-site support services, and utilities.

Major Support Equipment
    Support  equipment for the  microfiltration  system in-
cluded storage tanks for untreated and treated groundwater,
storage tanks for equipment washdown and decontamination
rinse waters, equipment for  treated effluent disposal, a
dumpster, a forklift with operator, a bulldozer with operator,
pumps, sampling equipment, health and safety-related gear,
and a van. Specific items include:
                                                      27

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                          Palmerton

                          Allentown
                       Philadelphia
SCALE:  1"  = 1 Mile
              Pennsylvania
Figure B-1.  PZS Site Location Map.
                                                         28

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        One 1,600-gallon tank mounted on a truck to
        transport the groundwater required to perform
        all test runs. Groundwater was collected from
        well RCRA-4, transported to the demonstration
        area, and pumped into a  6,000-gallon storage
        tank.
        One 6,000-gallon filtrate storage tank sized to
        contain the filtrate from all test runs.
        One 4,500-gallon storage tank to contain the
        equipment washdown and decontamination rinse
        waters.
        One 1,000-gallon storage tank to store tap water
        required  for   equipment  and  personnel
        decontamination.
    •   One 1,000-gallon storage tank to store deionized
        water required for equipment decontamination.
        One 1,600-gallon storage tank to temporarily
        store (1) the metals precipitate sludge remaining
        at the  end of each run, (2) filtrate collected
        during the cake drying cycle, and (3) equipment
        washwater.  This waste was temporarily stored
        in this tank until it was treated and pumped to
        the 4,500-gallon storage tank for appropriate
        disposal.
    •   One solid waste dumpster to store nonhazardous
        wastes prior to disposal.
        A number of 55-gallon drums to contain filter
        cake, used filter media,  and  used disposable
        health and safety gear prior to disposal.
        A high-pressure steam cleaner for decontam-
        inating  the storage  tanks  and  sampling
        equipment at the end of the demonstration.
    •   A bulldozer with operator to  clear and grade
        the demonstration area.
        A forklift with operator for setting up equipment
        and for moving drummed wastes.
    •   One pump  for  transferring the  contaminated
        shallow groundwater from well RCRA-4 to the
        tank truck,  and from  the tank truck to the
        untreated  groundwater  storage tank.   An
        additional pump was needed to transfer the
        filtrate from the filtrate storage tank to a tank
        truck.
        An air compressor and related equipment for
        generating compressed air at 90 psig minimum
        and 40 scfm capacity.  This compressed air was
        used in operating the microfiltration unit.
        Sampling equipment to sample filter cake and
        aqueous media.
        Analytical  equipment  for measuring field
        parameters at the demonstration site.
        Health and safety-related equipment, such as a
        first-aid kit  and protective coveralls,  latex  or
        similar inner gloves, nitrile outer gloves, steel-
        toe boots and  disposable overboots, safety
        glasses, and a hard hat.
    •    A van to  transport oversight personnel and
        supplies.

On-Site Support Services
    On-site laboratory analyses were  conducted in a  field
 trailer measuring 12 by 44 feet. The field trailer also served
 as an office for field personnel and provided shelter and
 storage for small equipment and supplies.  A personal com-
 puter and printer were used for data processing. Two chemi-
 cal toilets were located near the trailer.

 Utilities
    Utilities required for the demonstration included water,
 electricity, and telephone service. Water was required for the
 equipment and personnel decontamination and for drinking
 purposes. During operation  of the demonstration  unit, per-
 sonnel and  equipment decontamination required  about 50
 gallons  per day  (gpd) of tap water. Deionized water needs
 for final equipment decontamination were approximately 50
 gpd.  Drinking water needs were 5  to 10 gpd.

    Electricity was needed for the microfiltration system, the
 office  trailer,  and  the laboratory equipment.   The
 microfiltration system required 240-volt, 3-phase, 60-Hz, and
 20-amp electrical service.  Additional electrical power (110-
 volt,  single-phase) was needed mainly for operating the
 microfiltration system's agitators, lighting the office trailer,
 and operating the on-site laboratory and office equipment. A
 portable generator was used during the initial 2 weeks of the
 demonstration because Pennsylvamia Power and Light Com-
 pany could not provide the electrical connection due to rainy
 weather.

    Telephone service was required mainly  for ordering
 equipment,  parts, reagents  and other chemical  supplies;
 scheduling deliveries; and making emergency  communica-
 tions.

Technology Demonstration
    This section discusses operalional and equipment prob-
lems and health  and safety  issues associated with  the SITE
demonstration.

Operational Problems
    The SITE team experienced a few operational  problems
during the demonstration.  Some of these problems resulted
in changes in the demonstration schedule and duration, while
the others required making field decisions to solve  the prob-
lems.  These operational problems  and their resolutions are
described below.

        Pennsylvania Power and Light Company could
        not  provide electrical  power connection for
        onsite operations during the first 2 weeks  of
        demonstration. The SITE, team rented a portable
        generator to perform the field work during this
        period.  Although the generator could provide
        adequate power supply, field personnel had to
        make frequent trips to diesel fuel  stations  to
        obtain diesel for the generator.  Sometimes, the
        voltage fluctuations by the generator resulted in
        minor problems  in the  operation of field
        analytical instruments.
        According to the technology developers, several
        additional dry runs had to be performed because
        the  groundwater characteristics  during the
        demonstration were slighfly different from those
        for  the treatability studies performed  in June
                                                       29

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        1989. In the dry runs, it was found that the
        volume  of filtrate generated in each filtration
        cycle was significantly less than the quantity
        the developers anticipated. Because of this, the
        filtrate collection and recirculation  tanks were
        too large to implement the sampling procedures
        planned for  the demonstration. To solve this
        problem, significant  modifications  were made
        to the tanks used, the sampling approaches, and
        the number of cycles per run. This resulted in
        equipment  modifications  and  demonstration
        schedule changes.

Equipment Problems
    The SITE team experienced a few equipment problems
during the demonstration.  These problems resulted in (1)
repeating  the demonstration runs,  (2) onsite equipment
maintenance, and (3) changes in the demonstration schedule
and duration. These  equipment problems and their resolu-
tions are described below.

    •   At the beginning of the demonstration, the filter
        aid pump did not deliver the rated flow rate due
        to cold  weather. For example, when the pump
        was set at its maximum, it delivered only 16
        gallons  per hour (gph) instead of 40 gph. After
        the hydraulic oil in the pump warmed up and
        the filter pump was recalibrated onsite, the pump
        was able to deliver the desired flow rate.
    •   The filter feed pump  flow rate could not be
        controlled properly because of the excessive air
        supply  to the pump.  The developer replaced
        the 0.5-inch air line with 0.25-inch air line and
        this solved the problem.
        The moisture trap of the compressor was not
        adequate to dry  compressed  air  for proper
        functioning of  the microfiltration system.
        Because of this, the pneumatic controls of the
        microfiltration system  malfunctioned, and the
        pump flow rates could not be controlled properly
        in some runs. The moisture in the air lines had
        to be removed every  few hours to minimize
        moisture accumulation. The demonstration runs
        impacted by this problem had to be repeated.
     •   The ProFix  pump and  the  lines  clogged
        frequently.  To minimize this problem, ProFix
        was sieved through a Number 10 mesh size
        screen  and also ProFix slurry was diluted from
        9 percent to  6 percent.   According  to the
        developer, all commercially available ProFix is
        now screened to eliminate this problem.
     •   In one run, the filter media reroller did not
         function properly. The  filter media did not reroll
         automatically at the end of some filtration cycles
         because the  reroller  did  not have  adequate
         tension. The developer discovered that it was
         because the clutch on  the reroller  slipped. The
         clutch  was then repaired for proper functioning
         of the microfiltration unit.
     •    During the latter runs, it  was found  that the
         scraper bar on the microfiltration unit punctured
         the filter media because the scraper bar surface
        was not smooth. This problem was resolved by
        removing  the  scraper bar  and using a  new
        segment of filter  media.  This run was  also
        repeated.   The  developer  states  that  most
        commercially  available filters have  smooth
        scraper bars.

Health and Safety Considerations
    In general, health hazards associated with the demon-
stration resulted from the possibility  of exposure to the con-
taminated groundwater. Although the treatment system was
entirely closed, the potential routes  of exposure during the
demonstration were inhalation, ingestion, and skin and  eye
contact from possible splashes or spills during sample col-
lection.

    All personnel working in this area had, at a minimum,
40 hours of health and safety training and were under routine
medical surveillance.  Personnel were required to wear pro-
tective equipment appropriate for the activity being per-
formed.  Steel-toe boots were required in the exclusion zone.
Personnel  working in direct contact with contaminated
groundwater were in modified Level D protective equipment,
including safety shoes, latex inner gloves,  nitrile or Viton
outer gloves, and safety glasses.

Site Demobilization
    Decontamination was  necessary for the DuPont/Oberlin
demonstration unit, untreated groundwater storage tank, treated
effluent storage tank, and sampling equipment.

    The storage tanks were steam-cleaned at the end of the
demonstration program. Filtrate collected during the demon-
stration was tested and discharged into an on-site treatment
facility.  Filter cake, along with disposable protective cloth-
ing such as coveralls, was collected in 55-gallon drums and
disposed of at a permitted nonhazardous waste landfill.

    After the demonstration program was completed and on-
site equipment was disassembled and decontaminated, equip-
ment and  site demobilization activities began. Equipment
demobilization included loading the  skid-mounted  units on a
flat-bed trailer and transporting them off-site, returning rented
support equipment, and disconnecting utilities.

Experimental Design
    The objectives of the technology demonstration were to:
 (1) assess the technology's ability to remove zinc from the
groundwater at the PZS sjte under different operating condi-
 tions, (2) evaluate the system's ability to dewater the metals
precipitate from  treated  groundwater at the PZS site, (3)
 determine the  system's ability to produce a filtrate and a
 filter cake that meet applicable  disposal requirements; and
 (4) develop the information required to estimate the operat-
 ing costs for the treatment system,  such as electrical power
 consumption and chemical doses.

 Testing Approach
     The technology evaluation was performed in four phases.
 Phases 1 and 2 involved nine runs each, and Phases 3 and 4
 involved two runs each.   In Phase 1, chemical operating
 parameters (precipitation pH and ProFix dose) were varied,
                                                         30

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 and the filter operating parameters (blowdown pressure and
 blowdown time) were kept constant.  In Phase 2, the filter
 operating parameters were varied, and the chemical operat-
 ing parameters were kept constant.  Phase 3 runs were per-
 formed to evaluate the reproducibility of the microfiltration
 system's  performance.  Phase  4 runs were performed to
 evaluate the reusability of the Tyvek® Filter.

     Table B-l summarizes the operating conditions for the
 demonstration runs. For Phase 1 runs, the initial operating
 conditions (Run 1) were based on a pilot-scale treatability
 study performed by DuPont/Oberlin on the PZS site ground-
 water.  During the demonstration,  the chemical operating
 conditions and the filter operating conditions were optimized
 in Phases 1 and 2, respectively. Since Run 5 conditions were
 selected as  the  optimum operating conditions for Phase 1,
 these were set as the initial conditions for Phase 2.  Phases 3
 and 4 were performed at Run 13 conditions because these
 conditions were selected as the overall optimum operating
 conditions.  This experimental design assumes that there is
 no interaction effect between the chemical  and filter operat-
 ing parameters.  Although this assumption is not critical to
 evaluating the microfiltration system based on the  technol-
 ogy demonstration objectives,  the  technology  developers
 agreed with this assumption based on their experience.

 Sampling and Analytical Procedures
    Solids  and water samples  were collected  from the
 microfiltration system at the locations shown on Figure B-2.
 The following measurements  were considered critical  to
 evaluating the microfiltration system:  (1) zinc in the untreated
 groundwater and filtrate, (2) total suspended solids (TSS)
 before and  after the microfiltration  unit,  (3) free  liquids
 (paint filter liquids test) and moisture content in the filter
 cake, and (4)  pH of the untreated groundwater and filtrate.
 Several noncritical  measurements were also performed, in-
 cluding the extraction procedure (EP) toxicity test and toxic-
 ity characteristic leaching procedure (TCLP) test for the filter
 cake, and particle size distribution for the  filtrate.  For the
 critical  measurements, about three to six replicate samples
 were  collected depending on the data variability.  Duplicate
 samples were collected for noncritical measurements.

    EPA-approved  sampling, analytical, quality assurance,
 and quality  control (QA/QC) procedures were followed  to
 obtain reliable data.  Details on QA/QC procedures are pre-
 sented in  the demonstration plan (PRC, 1990).  Table B-2
 summarizes  analytical and measurement methods.

Review of Treatment Results
    This section summarizes the results of  both critical and
noncritical parameters for the DuPont/Oberlin microfiltration
system  demonstration  and evaluates the  microfiltration
technology's effectiveness in treating groundwater contami-
nated with zinc.

Summary of Results for Critical Parameters
    Results  for  the critical  parameters were evaluated for
each of the four phases.

Phase 1 Results
    The total zinc concentrations in the untreated groundwa-
 ter and filtrate are presented in Figure B-3 for varying pre-
 cipitation pH and ProFix doses.  The zinc concentrations in
 the untreated groundwater, ranging from 417 to 493 mg/L,
 were reduced to about 0.1 mg/L (except  in Run 6), yielding
 a typical removal efficiency of Beater  than 99.9  (3 logs)
 percent. In Run 6, the filtrate zinc concentration was an order
 of magnitude higher than the typical filtrate  zinc level; this
 increased concentration  cannot be explained.  No definite
 trend was identified for effluent zinc levels or zinc removal
 efficiencies with varying pH or ProFix dose.

     During the demonstration, a simple of the influent to the
 microfiltration unit was filtered through a standard 0.45-pm
 membrane filter (commonly used to measure dissolved) met-
 als) to compare the resulting filtrate with T-980 filtrate. In all
 cases, the zinc concentration was  less in the T-980 filtrate,
 indicating the possible superior performance of Ty vek® T-980
 filter media.

    Figure  B-4 presents the TSS  concentration profiles for
 influent and filtrate. These data show that the influent TSS
 concentrations ranged from 6.5601 to 18,900  mg/L, and the
 filtrate TSS concentrations ranged from  8.4  to 31.5  mg/L.
 The TSS  removal efficiencies  ranged from  99.69 to 99.95
 percent.  Neither filtrate TSS levels nor TSS removal effi-
 ciencies seemed to follow a definite trend with varying pH or
 ProFix dose.

    The filter cake solids levels are presented on Figure B-5.
 This figure shows that cake solids ranged from 30.5 to 47.1
 percent.  This figure also  shows mat the cake percent solids
 increased as the pH or ProFix dose increased.  The filter cake
 passed the  paint filter liquids test  in all runs, making it
 suitable for landfilling.

    The filtrate pH was typically about 11.5,  irrespective of
 the precipitation pH due to the high  pH (about 12.6) of the
 ProFix slurry added at the influent to  the microfiltration unit.

    At the end of Phase 1, Run 5 conditions were selected as
 the optimum chemical operating conditions based on (1) zinc
 and TSS removals, (2) zinc and TSS levels in  the filtrate, (3)
 percent solids in the filter cake, and (4) the cost of treatment
 chemicals (lime and ProFix).

 Phase 2 Results
    Figures B-6, B-7, and B-8 present  the  concentrations
 profiles for  zinc, TSS, and filter cake solids, respectively.
 These results are similar to Phase 1 results. The filter cake
 passed the paint filter liquids test in all Phase 2 runs, and the
 filtrate pH was typically about 11.5 (same as that in Phase 1
 runs).

    A  dissimilarity  was noted between  the Phase 1 and
 Phase 2 results for Tyvek® T-980 filtrate and 0.45-|im fil-
 trate.   In the Phase  2  runs, the zinc concentrations in the
Tyvek® T-980 filtrate were not always less man the 0.45-|jm
 filtrate.  This dissimilarity cannot be explained.

    At the end of the Phase 2 runs, Run 13 conditions were
selected as the optimum  operating conditions based on the
criteria discussed for Phase 1,  plus  waste processing time
(which includes blowdown time).
                                                        31

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Table B-1.  Operating Conditions for the Demonstration Runs
Phase Run No.
1 1
2
3
4
5
6
7
8
9
2 10
11
' 12
13
14
15
16
17
18
3 19
20
4 21
22
Precipitation pH
8
9
10
8
9
10
8
9
10
9
9
9
9
9
9
9
9
9
9
9
9
9 I
ProFix Dose (g/L)
6
6
6
12
12
12
14
14
14
12
12
12
12
12
12
12
12
12
12
12
12
12
Time (Min)
2
2
2
2
2
2
2
2
2
0.5
2
3
0.5
2
3
0.5
2
3
0.5
0.5
0.5
0.5
Pressure(psig)
45
45
45
45
45
45
45
45
45
30
30
30
38
38
38
45
45
45
38
38
38
38
Phase 3 Results
    The total zinc concentration in the untreated groundwa-
ter in Runs 19 and 20 (reproducibility runs performed at Run
13 operating conditions) was 465 mg/L.  This was reduced
by 99.95 and 99.94 percent, resulting in 0.24 and 0.28 mg/L
of zinc in Runs 19 and  20,  respectively. These  removal
efficiencies agree with the removal efficiency achieved in
Run  13 (99.95 percent), indicating that the microfiltration
system's performance in removing zinc was reproducible.
    The TSS  concentrations  in  the influent  to the
microfiltration unit were 14,300 and 14,000 mg/L in Runs 19
and 20, respectively.  These were reduced by 99.95 percent,
resulting in 7.7 and 6.8 mg/L of TSS in Runs  19 and 20,
respectively. This removal efficiency also  agrees  with the
TSS removal efficiency observed in Run  13 (99.91 percent),
indicating that the system's performance in removing TSS
was reproducible.
                                                        32

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   Groundwater
                                                                                                  Liquid Sampling Location


                                                                                                  Solids Sampling Location
                                                                                                             — To
                                                                                                             Disposal
                         To
                      Disposal
                                                                                                          To  Liquid
                                                                                                       Waste Storage
                                                                                            nitrate
                                                                                         Recirculation
                                                                                             Tank
Figure B-2. Microfiltration System Sampling Locations.
                                                                33

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Table B-2. Analytical and Measurement Methods
Parameter
Metals (total)
Metals (dissolved)
EP Toxicity
TCLP
Metals (total)
Free Liquids
Moisture Content
TSS
Acidity
Particle Size
Temperature
pH
Turbidity
Volume
Mass
Electricity
Consumption
Notes a L = Liquids
S = Solids
O = Others
Matrix'
L
L
S
S
S
S
S
L
L
L
L
L
L
S,L
S
0

Method
Type
Lab
Lab
Lab
Lab
Lab
Field,
Field
Field
Field
Lab
Field
Field
Field
Field
Field
Field

Method Reference
SW-846 3010/6010b
SW-846 3005/6010b
SW-846 1310b
SW-846 3010/6010b
40 CFR Part 268°
SW-846 3050/6010
SW-846 9095b
SM209F1
MCAWW 160.2e
MCAWW 305 le
Coulter Corporation
Manufacturer Spec.
MCAWW 170.1e
MCAWW 150.16
MCAWW 180. le
NAf
NAf
NAf

Title
Metals by ICP
Metals by ICP
Extraction
Metals by ICP
Toxicity
Characteristic
Leaching
Procedure
Metals by ICP
Paint Filter
Liquids Tests
Percent Solids
Residue
(filterable)
Acidity
(Titrimetric)
Particle Size
Analysis
Temperature
pH
Turbidity
Volume
Mass
Electricity
Consumption

b U.S. EPA. 1986.
c. 40CFR.1988
d APHA.AWWA.andWPCF, 1989.
c U.S. EPA, 1983
f NA = Not available
                                                   34

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    Figure B-9 compares regulatory thresholds with (1) the
95 percent upper confidence limits (UCL) for filtrate metals
Cadmium, lead, and zinc) and TSS and (2)  the  average
filtrate pH value,  the regulatory thresholds are those that
would be required  for  discharge  into  a local  waterway
(Aquashicola Creek) if an NPDES permit were required. The
UCLs were calculated using  the one-tailed Student's t-test.
To calculate UCLs for cadmium and lead, which were present
below detection  limits, their mean concentrations  were esti-
mated using standard statistical procedures. Figure B-9 shows
that the filtrate met the NPDES limits for metals and TSS.
However, the NPDES limit for pH was not met.

    Figure B-10 presents the composition of the filter cake in
the reproducibility runs. Percent solids in the filter cake was
about 41. Of these solids, about 80  to 90 percent were from
ProFix, and the remaining were from (1) TSS present in the
untreated groundwater: (2) metals precipitated during  the
treatment; and (3) any unreacted lime from pH adjustment.

    As a quality control check, a mass balance was per-
formed for zinc and TSS  in Runs 19 and 20. The mass
balance results for zinc showed that the  difference between
zinc in and zinc out was about  15 percent, which is within
analytical precision (+ 25 percent).  Similarly, TSS measure-
ments were also within analytical precision (± 30 percent).

Phase 4 Results
    The results for the Tyvek® reusability runs (Runs 21 and
22) are presented on Figure B-ll.  In these runs, the same
portion of Tyvek® was used repeatedly for six cycles. Samples
were composited after the first three cycles (Run 21) and the
last three cycles (Run 22).   Figure  B-ll shows that  the
microfiltration unit's performance was unaffected even after
multiple uses of Tyvek®.

Summary of Results for Noncritical Parameters
    The  demonstration also  evaluated  the  results  for
noncritical parameters such as filter cake toxicity characteris-
tics and the filtrate particle size distribution. Toxicity charac-
teristics were considered a noncritical  parameter because EP
and TCLP metals were  present at very low levels in  the
untreated groundwater.  The particle size distribution mea-
surement was included primarily to  evaluate the developers'
claim that the Tyvek® filter can remove particles down to 0.1
micron (|J.m).  The filter cake toxicity characteristics were
determined using EP and TCLP tests. A composite filter cake
sample collected from the  demonstration runs passed both
these tests, indicating that the filter cake could be disposed of
as a nonhazardous waste.

    Figure B-12 presents the filtrate particle size distribution
and TSS results for the reproducibility runs. The particle size
was measured using a Coulter counter with a 0.5-to 500-|j.m
measurement range. The data presented  on this figure indi-
cate that the majority of particles present in the filtrate were 1
to 4 pun  in size. The TSS data for these runs were used
together  with  the particle size distribution to estimate  the
particle concentration  in  each size  range. In Run  13  for
example, filtrate particles ranging from 1 to 2 pm and greater
than 8 pm were present at 6.3 mg/L and 0.63 mg/L, respec-
tively.  These results do not support the developers' claim
that the Tyvek® filter can remove particles down to 0.1 pm.
Similar observations were made for Runs 19 and 20.

    After reviewing the particle size distribution  and TSS
data, DuPont stated that the TSS  measured in the filtrate was
the result of postprecipitation of calcium carbonate solids.
DuPont provided X-ray diffraction data for the TSS  collected
on  a 0.45-jim  filter by  processing the  filtrate  from  the
microfiltration unit in  Phase 1 runs. The X-ray diffraction
data showed a much stronger peak for calcium carbonate
solids than for zinc solids; however, quantitative data were
not available.  DuPont also stated that the filtrate turbidity it
measured immediately after sample collection typically ranged
from 0.1 to 0.3 NTU  and that TSS  values were about  0.2
mg/L.  These levels are lower than those observed  by EPA,
although EPA analyzed its samples well within the holding
times specified by EPA-approved analytical methods. DuPont
observed that both turbidity and TSS levels in the  filtrate
samples increased overnight, indicating postprecipitation ef-
fects.  Such observations were not made during the pilot-
scale tests performed before the  demonstration, perhaps  be-
cause die batch of groundwater  used during the pilot-scale
testing was different from that used during the demonstra-
tion.

Conclusions
    The DuPont/Oberlin microfiltration system achieved the
following: (1) zinc and TSS removal efficiencies of 99.69 to
99.99 percent and (2) solids in the filter cake of 30.5 to 47.1
percent.  At the optimum conditions (Run 13), the  zinc and
TSS removal efficiencies were about 99.95 percent and  the
filter cake solids were about 41 percent.

    ProFix contributed a significant portion (80 to 90 per-
cent) of solids to the filter cake.  The remaining solids were
due to precipitated metals, TSS from the untreated ground-
water, and any unreacted lime.

    The zinc and TSS removal efficiencies and the filter
cake percent solids were unaffected by the repeated use (six
cycles) of the Tyvek® filter media. This indicates that  the
Tyvek® media could be reused without  adversely  affecting
the microfiltration system's performance.

    The filtrate met the applicable NPDES permit  limits,
established for disposal into a local waterway, for metals and
TSS at the 95 percent confidence  level. However, the filtrate
did not meet the NPDES permit limit for pH. The filtrate  pH
was typically 11.5, while the permit limit is 6 to 9.

    The filter cake passed the paint filter liquids test for all
runs.  Also, a composite filter cake sample from the demon-
stration runs passed the EP toxicity and TCLP tests.
                                                        35

-------
                              Zinc Concentration, mg/L
      .01
             .1
10
100
                                                                           1,000
          lUlUIUUlUIUttl.
           Run1  i
           illllililll!l!il.06
pH  9
      10
UilitlUUlUMM
 Run 2
               !.07
          lUUUIUIUUIUU
          Run3
                  XJ8J
                                                                  417
                                                                  417
                                                                                     LOW
                                                                                     PROFIX
                                                                                     DOSE
                                                                                     (6Q/L)
        .01
                    .1
                                        10
             100
             1,000
  pH  9
                                                                                   MEDIUM
                                                                                   PROFIX
                                                                                   DOSE
                                                                                   (12Q/L)
                                                              100
                                                                         1,000
                                                                                     HIGH
                                                                                     PROFIX
                                                                                     DOSE
                                                                                     (149/L)
                       Untreated Groundwater
                                                                   Filtrate
Figure B-3. Zinc Concentration Profiles for Phase 1 Runs.
                                                 36

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                                TSS Concentration, mg/L
                                    100          1,000         10,000
   100,000
                                                                                    LOW
                                                                                    PROFIX
                                                                                    DOSE
                                                                                    (69/L)
    PH
                                                 1,000         10,000
                                                       I  I  I I I I I
    100,000
    pH  9
            .•'".".  .'".-'V  ll,31.5
            MEDIUM
            PROFIX
            DOSE
            (12g/L)
                                                                          100,000
             HIGH
             PROFIX
             DOSE
             (14Q/L)
                         Influent to Microfiltration Unit
Filtrate
FigureB-4. TSS Concentration Profiles for Phase 1 Runs.
                                                37

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                                  Cake Solids, %
                      10
   pH  9
                                          LOW
                                          PROFIX
                                          DOSE
                                          (6g/L)
                      10
20
                                                                             MEDIUM
                                                                             PROFIX
                                                                             DOSE
                                                                             (12g/L)
                                                                             HIGH
                                                                             PROFIX
                                                                             DOSE
                                                                             (149/L)
Figure B-5. Filter Cake Solids for Phase 1 Runs.
                                            38

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                            Zinc Concentration, mg/L
                                                     100      1,000
 Slowdown
 Time, min.
                                                       LOW
                                                       SLOWDOWN
                                                       PRESSURE
                                                       (30psig)
                                                     100      1,000
 Slowdown
 Time, min.
                                                       MEDIUM
                                                       SLOWDOWN
                                                       PRESSURE
                                                       (38psig)
              .01
         .1
           0.5
 Slowdown
 Time, min.
Run 17 lilt
10
100      1,000
                           HIGH
                           SLOWDOWN
                           PRESSURE
                           (45psig)
                           Untreated Groundwater

Figure B-6. Zinc Concentration Pofiles for Phase 2 Runs.
                                          Filtrate
                                           39

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                              TSS Concentration, mg/L
                                 100       1,000
                                      i  L.'... '..'.. '..'.I i   .'
                                                       10,000     100,000
                                                          .1  — ' — ' — ' ' ' ' "
  Slowdown  2
  Time, min.
                                                                        LOW
                                                                        SLOWDOWN
                                                                        PRESSURE
                                                                        (30psig)
             0.5
  Slowdown
  Time, min.
     10        100
~i—i i i i iii	"i  i i i~n
               Run 13
                       1:10.9
               Run 14
                       18.3
                 Run 15
                                           1,000
                                      -j ....... i i i 1 1 1 n   i
                                                        10,000      100,000
                                                            "i—i—i i i 111
                                                     12,500
                                                     9,460
                                                      15,100
                                                     MEDIUM
                                                     SLOWDOWN
                                                     PRESSURE
                                                     (38psig)
                                              1,000      10,000      100,000
           0.5


Slowdown  2
Time, min.
                                                                          HIGH
                                                                          SLOWDOWN
                                                                          PRESSURE
                                                                          (45pslg)
                  Klllliil  Influent to Microfiltration Unit    [ i:;;,:,!;,:,;!  Filtrate

Rgure B-7. TSS Concentration Profiles for Phase 2 Runs.
                                             40

-------
                                  Cake Solids, %
 Blowdown
 Time, min.
LOW
BLOWDOWN
PRESSURE
(30psig)
 Slowdown
 Time, min.
Run 14 ';;;j:";:',!i: -, .;j!S"_ ,!jj|jt  ' ^X!  ' .. ..''Ijiji.;;''", |'|"''41.8
MEDIUM
BLOWDOWN
PRESSURE
(38psig)
 Slowdown
 Time, min.
HIGH
BLOWDOWN
PRESSURE
(45psig)
Figure B-8. Flilter Cake Solids for Phase 2 Runs.
                                           41

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    10,000E
     1,000
  0)
  O   100
  10
  O5
        10
Regulatory Threshold

      RT = 200
                                                 Metals
                                                 RT = 700
                                                                                Zinc
                        TSS
                                                                PH
        40
  J    30


   I

  _F
  O    20
  to
  O5
        10
                        RT = 30
                                               14
                                                             12
                                           ID   8

                                           X

                                            °-  6



                                                4



                                                2




                                                0
                                                                     . 13  4.
 IRun r

k- 19  y.-
I 20  jr.
Rgura B-9. Comparison of Filtrate Quality for Reproduclbility Runs with Regulatory Thresholds.
                                                  42

-------
Figure B-10. Filter Cake Composition for Reproducibility Runs.
                                                           43

-------
                                  Zinc Concentration, mg/L
                                       1             10           100
                                            1,000
                        10
TSS Concentration, mg/L
   100          1,000        10,000        100,000
                                       Cake Solids, %
                                  30                     40
                                             50
                     Untreated Groundwater
                     Influent to Microfiltration Unit
Rgure B-11. Tyvek" Performance for Reusability Runs.
                             ;M/:n;,   Filtrate
                                     Filter Cake
                                                44

-------
                         10
Number of Particles, percent


     20           30           40
                                                          34.6
50
                                   rss =
                                   18.3 mg/L
                                                                                  RUN 13

   N

   CO

   ^)

   O
                                                 RUN 19

   N
   CO
   JO)
   o

   '
                                                 RUN 20

Figure B-12. Filtrate Particle Size Distribution for Reproducibility Runs.
                                               45

-------
References
APHA, AWWA, and WPCF, 1989.  Standard Methods for
    the Examination of Water and Wastewater, 17th Ed.,
    Washington, D.C.

40 CFR, Part 268, 1988. Toxicity Characteristic Leaching
    Procedure (Appendix I).

U.S. EPA, 1983.  Methods for the Chemical Analysis of
    Water and Wastes,  EPA-600/4-79-020  U.S. EPA
    Environmental  Monitoring and  Support  Laboratory,
    Cincinnati, Ohio.
PRC, 1990.  Demonstration Plan for the DuPontlOberlin
    Microfiltration  System, prepared  for U.S. EPA, April
    1990
U.S. EPA 1986.  Test Methods for Evaluating Solid Waste,
    Volumes IA-IC: Laboratory Manual Physical/Chemical
    Methods; and  Volume  II:   Field Manual, Physical/
    Chemical Methods, SW-846,  Third Edition, Office of
    Solid Waste, Washington, D.C.

ZCA, 1987.  Draft Remedial Investigation Report for the
    Palmerton Zinc Superfund Site, Palmerton, Pennsylvania.
                                                      46

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                                               Appendix C
                                               Case Studies
Introduction
    This appendix summarizes case studies on the use of the
DuPont/Oberlin microfiltration technology. These case stud-
ies describe the performance of full-scale DuPont/Oberlin
microfiltration units treating industrial wastewaters. The in-
formation  available for these case studies varies from de-
tailed analytical and cost data to relatively little information
on system performance and cost. The following case studies
are summarized in this appendix:
Case Study
Facility and Location
    C-l     Westinghouse Savannah River Site, Aiken,
            South Carolina

    C-2     DuPont Electronics Materials, Inc., Manati,
            Puerto Rico

    C-3     DuPont Electronics, Sun Valley, California
                                                      47

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                                             Case Study C-l
                                 Westinghouse Savannah River Site
                                         Aiken, South Carolina
    This case study presents the results of full-scale testing
and use of a DuPont/Oberlin microfiltration system at the
Weslinghouse Savannah River site (SRS) in Aiken, South
Carolina. The microfiltration system uses Tyvek® T-980 filter
media to remove submicron particles from wastewater.  SRS
began using this system in July 1985 to treat wastewater from
its metal finishing and aluminum forming operations and
from an autoclave process.

    A series of tests were conducted to evaluate the effec-
tiveness of the DuPont/Oberlin microfiltration system at the
SRS.  The performance of the filtration unit was studied as a
function of several variables including filter media, filter aid,
and polymer additive. The results of these tests are presented
below. The information presented in this case study is based
on a paper presented by Mr. Hollis Martin of Westinghouse
at the American Electroplaters and Surface Finishers/Envi-
ronmental Protection Agency (EPA) Conference on Ppllution
Control for the Metal Finishing Industry in January 1989, as
well as current data on system operations provided by Mr.
Martin.

Facility Operations
    The Savannah River Plant produces nuclear materials for
the U.S. Department of Energy (DOE). The facility is man-
aged for DOE by Westinghouse as of April 1, 1989 (prior to
that by DuPont).  Fuel and target assemblies for the nuclear
reactors of the Savannah River Plant are fabricated in the
300-M area of the facility. Metal finishing, aluminum form-
ing, and various  cleaning operations in the 300-M area pro-
duce effluents that discharge to a wastewater treatment plant.
Principal metals  in the wastewater include uranium, alumi-
num, nickel, lead, zinc, copper, and chromium. These metals
are removed from the effluent by wastewater equalization,
precipitation,  flocculation, and  microfiltration.    A second
waste stream, consisting of insoluble metal oxides from auto-
clave test effluent, is treated by a separate wastewater equal-
ization and microfiltration system. The chemical composi-
tions of wastewaters from 300-M area and autoclave opera-
tions are shown in Table C-l-1.

    Prior  to  undergoing pressure filtration, 300-M  area
wastewater is acidified to pH 3,  and aluminum sulfate is
added to ensure phosphate removal. The pH is then raised to
approximately 8 by addition of sodium hydroxide to precipi-
tate the metals.   This pretreated wastewater is filtered using
the microfiltration system, which is the primary unit opera-
tion in treating 300-M area  wastewater. The filtrate is  ana-
lyzed and discharged to Tims Branch Creek in  South Caro-
lina. The average composition  of the filtrate discharged in
June  1990 and  associated  National Pollutant Discharge
Elimination System (NPDES) limits are presented in Table
C-l-1. The filter cake contains both hazardous (F006) and
radioactive material; therefore, it is considered a mixed waste.
Prior  to disposal, the filter cake is  stabilized and solidified
with cement.  The treated filter cake is subject to hazardous
waste land disposal restrictions.

System Performance
    The performance of the DuPonl/Oberlin microfiltration
systems was  evaluated following changes  in filter media,
filter aid, and polymer additives. These investigations were
motivated by a rising peak demand for the two filtration
units and a consequent need for greater efficiency. The ef-
fects of these changes and a summary of the maintenance
provided for the system over the last 5 years are presented
below.

Filter Media
    The Oberlin pressure filtration systems were installed at
the 300-M area of the Savannah River Plant in July 1985.
The filtration  area of each unit is 24 square feet.  Originally,
Tyvek® 1042B was chosen because of its high filtration effi-
ciency and good sheet tensile and tear strength compared to
other  filter media. When DuPont developed a new Tyvek®
series specifically designed for filtration applications, DuPont
conducted tests comparing the new Tyvek® T-980 media with
the original Tyvek® 1042B. Wastewater from the 300-M and
autoclave areas were used to test the two Tyvek® materials; the
same batches  of wastewater were used for the comparison.

    Tyvek® T-980 increased the cycle time and average flow
rate through the filter by  13 and 11 percent,  respectively, for
effluent from  the 300-M area operations.  The filtrate turbid-
ity did not differ significantly between the two filter media.
For the autoclave wastewater, the cycle time remained ap-
proximately the same; however, the average flow rate through
the filter increased by 9 percent, and the  filtrate turbidity
decreased by  40 percent.  The increased filtration flow rate
observed for both systems using Tyvek® T-980 indicates that
the new  filter  media  increases  the  efficiency  of the
microfiltration system.

    Tyvek® T-980 was also compared to other filter media,
such as a wet cast microporous membrane, biaxial stretch
polytetrafluoroethylene laminated membrane, and melt blown
polypropylene media. The performance of these media com-
pared to Tyvek® T-980 for filtering the 300-M area wastewa-
ter was investigated.  Tyvek® T-980 outperformed other filler
media by producing  a clearer filtrate with  the best cake
release from the media.  Furthermore, the  filter  cake from
Tyvek® T-980 had the highest solids content. A high solids
                                                       48

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Table C-l-1. Operating Data for the DuPont/Oberlin Microfiltration System
Contaminant
   300-M
Wastewater*
   mg/L
Filtrate
mg/L
Autoclave
Wastewater"
mg/L
                                                                                       NPDES Permit Limits
Filtrate
mg/L
Daily Max.
  mg/L
Monthly Average
   mg/L
Uranium
Aluminum
Nickel
Lead
Zinc
Copper
Cadmium
Chromium
Nitrate (as N)
Phosphate (as P)
pH
Total Suspended
Notes: a
b
c
2.59
180.0
12.14
0.79
0.54
0.18
<0.1
0.1
685.0
4.46
8.4
Solids 800
0.03
1.97
<0.1
0.1
<0.1
<0.1
<0.1
<0.1
634.0
3.00
8.3
5
16.3 < 0.1
0.25 < 0.1
0.04 < 0.1
0.04 < 0.1
< 0.1 < 0.1
0.04 < 0.1
< 0.1 < 0.1
< 0.1 < 0.1
0.03 < 0.1
0.11 <0.1
NAC NA
300 <4
1.0b
6.43
2.46
0..69
0..64
0,42
0.1
1..24
l,355.0b
16.7b
6.0 - 10.0
60
0.5"
3.2
1.23
0.43
0.32
0.21
0.05
0.62
677.0b
6.83b
NA
31
The values are monthly averages based on daily analyses.
These values are only guidelines.
Not available.
content generally indicates a lower volume of waste requir-
ing disposal.

Filter Aid
    Fine grades of diatomaceous earth were initially used as
filter aids in 300-M area wastewater treatment with the Tyvek®
1042B media.  When a significant concentration of 1 to 3
micron particles (nickel and iron) were present, Celite 577
was used; when wastewater contained particles greater than 3
microns, Standard Super-Cel was used.  These  filter aids
were  tested against PerFLO 30SP, a new high-grade filter
aid. DuPont compared the performance of selected combina-
tions  of filter media and filter aid while  filtering the same
batch of wastewater.

    Investigations using 300-M area  wastewater focused on
the traditional combination of Tyvek® 1042B  and  Celite 577
and the new combination  of Tyvek® T-980 and  PerFLO
30SP. Compared to Tyvek® 1042B and Celite 577, the com-
bination of Tyvek® T-980 and PerFLO 30SP produced better
results:  the filtrate contained 45 percent less  suspended
solids and the average flow rate through the  filter increased
by a factor of 2.5.   In addition, the filtration cycle time
                            doubled.  The increase in both the filtration cycle and the
                            flow rate resulted in approximately 5 times as much waste-
                            water filtered per cycle, and 80 percent less filter media was
                            used. The amount of filter aid required decreased 20 percent
                            with PerFLO 30SP compared to Celite 577.

                                A different set  of filter media/filter aid combinations
                            were used to test filtration of the autoclave wastewater.  In
                            this test series, Tyvek® T-980 was investigated using both
                            Celite 577 and PerFLO 30SP and compared to Tyvek® 1042B
                            and Standard Super-Cel.  Although PerFLO 30SP greatly
                            improved the performance  of the 300-M area wastewater
                            filtration system, it did not enhance the performance of the
                            autoclave wastewater filtration system. The combination of
                            Tyvek® T-980 and Celite 577 yielded the best results.  Al-
                            though the  feed cycle remained constant for all combina-
                            tions, flow  rate increased 45 percent and the turbidity de-
                            creased 90 percent when Celite 577  was used.  The micro-
                            structure of PerFLO 30SP, compared to diatomaceous earth
                            filter aids, limited the ability to caplure very fine metal oxide
                            particles found in the autoclave effluent.
                                                        49

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Polymers
    During early operation of the microfiltration units, an
anionic polymer was added to the wastewater to increase
filtration efficiency.  However, the polymer activation tank
was too large, allowing the polymer to age and form an
unfilterable slime.  Therefore, use of polymer was tempo-
rarily discontinued.

    Improvements in polymers and activation systems stimu-
lated new interest in polymer addition.  Laboratory tests
indicated that 0.5 mg/L Praestol A3040L anionic polymer
would triple the filtration rate of metal hydroxide wastewater
containing 500 to 600 mg/L total suspended solids (TSS),
and 8 mg/L Praestol K144L cationic polymer would double
the filtration rate of metal phosphate wastewater containing
800 to 1,000 mg/L TSS when used with PerFLO  30SP filter
aid and Tyvek® T-980 filter media.   Unique anionic and
cationic polymer addition systems  were installed for full-
scale evaluation.

    The performance of the polymers met with laboratory
expectations.  Presently, 8 mg/L of Praestol K144L is used to
enhance metal phosphate  removal  from the wastewater.
Polymer addition further enhances the Tyvek® T-980/PerFLO
30SP combination by decreasing filter media and filter aid
usage by 7 and 3.4 times, respectively.

Maintenance
    Due to a hydraulic problem in the filter feed system (not
part of the DuPont/Oberlin system), the filters have cycled at
four times their normal rate. Despite this excessive cycling,
maintenance  during the 5 years  of operation was minimal.
The media support belt is replaced about every 3 months,
and the diaphragm of the filter fed inlet valve is replaced
annually.  The high pressure air bags on the upper platform
were replaced once in the past 5 years as a precaution.  The
belt chains were replaced one time after a mechanic improp-
erly installed a replacement belt The Wilden M2 filter aid
feed pump diaphragms are replaced about every 6 months.
The top platen seal was replaced once in the past 5 years.

Costs
    Solids removal capacity of the 300-M area and auto-
clave  wastewater treatment  facilities  has been greatly in-
creased by the improved filter aid and media.  The cost of
PerFLO 30SP filter aid is half that of fine grades of diatoma-
ceous earth; moreover, 20 percent less is needed.  The new
filter media (Tyvek® T-980)  also costs less to manufacture,
and 80 percent less is used. The operating and maintenance
cost, including polymer, filter aid, and filter media, is about
5 dollars per 1,000 gallons of wastewater processed.
Conclusions
    Performance of the  DuPont/Oberlin microfiltration sys-
tem for  removing suspended metal hydroxides and metal
phosphates from wastewater is maximized by using Tyvek*
T-980 as the filter media, in conjunction with PerFLO 30SP
filter aid and Praestol K144L cationic polymer. The volume
of filter cake requiring disposal decreased by 15 percent.
Results of extraction procedure toxicity and toxicity charac-
teristic  leaching procedure (TCLP) analyses of the  listed
F006  mixed waste produced by this configuration satisfy
land disposal restrictions. EPA is reviewing the Westinghouse
petition for delisting  the spent filter rolls.  The effluent from
the microfiltration unit meets all NPDES requirements.
                                                        50

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                                             Case Study C-2
                                DuPont Electronics Materials, Inc.
                                         Manati, Puerto Rico
    This case study presents information provided by DuPont
Electronics Materials, Inc. (DEMI) on the application of the
DuPont/Oberlin microfiltration system at the company's fa-
cility in Manati, Puerto Rico. Little information is available
for this case study regarding facility operations, system per-
formance, and costs.

Facility Operations
    Operations at the  DEMI facility produce a wastewater
slurry of 2,000 gallons per day. The slurry contains 1,000 to
5,000 parts per million (ppm) of suspended "frit" (calcinated
or partly fused, high-lead content glass material) and 2,000
to 10,000 ppm of total suspended solids.

System Performance
    The objective of the facility's microfiltration  treatment
unit is to remove suspended particulates from the wastewater
slurry ranging from 0.5  to  30 microns in size.   Before
filtration, two additives are combined with the wastewater to
assist in filtration: a filter aid and an organic polymer. The
filter aid is an amorphous volcanic aluminum silicate.  Ap-
proximately 12 pounds of filter aid is added per filtration
cycle (440 gallons of process  water).  Approximately 10
milliliters of 0.1 percent quaternary acrylamide cationic poly-
mer is added per cycle.
    The microfiltration system uses Tyvek® T-980 filter me-
dia.  According to DuPont, the microfiltration system re-
placed 0.45 micron cartridges, which were costing the plant
$1,200 per day. Additional filter cartridges rated at 10 and 1
micron (Filterite U10AW20U and U1AW20U, respectively)
are used following the microfiltration system to ensure that
particles less than 1 micron in size have been removed. This
additional filtering is conducted in case any operational prob-
lems have occurred with the microfiltration system.  The
microfiltration system, with filter cartridges, removes nearly
all particles between 0.5 and 30 microns.

    The filtration system is operated automatically and re-
quires only plant air and electricity (110 volts).  Each treat-
ment cycle lasts approximately 20 to 30 minutes and pro-
cesses  about 440 gallons of frit-containing  water. No data
were available for blowdown times, operating pressures, or
other operating parameters.

Costs
    Maintenance and operating costs for this system are low.
The system only requires attention for 5 minutes every half
hour for the operator to add polymer and filter aid manually.
Valves, diaphragms, and other minor parts require occasional
replacement.
                                                      51

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                                            Case Study C-3
                                          DuPont Electronics
                                        Sun Valley, California
    The Component Materials Division of DuPont Electron-
ics  manufactures  ceramic  dielectric powders  used  in  the
multilayer ceramic capacitor industry. This case study is
based on data provided by the facility; more detailed infor-
mation describing facility  operations, system performance,
and costs are not available.

Facility Operations
    The ceramic powders  manufacturing process produces
two  liquid waste streams  containing a complex array of
metal oxides and titanates.  Elements with the highest con-
centrations are barium, titanium, neodymium, bismuth,  and
lead.   The compositions  of the two waste streams vary
according to daily operations, but lead and total suspended
solids levels are typically in the range of 0.5 to 5.0 percent.
The treatment objective is to reduce the concentration of
metals to meet applicable effluent limits. Most of the metals
are in the form of suspended solids; there is no chemical or
physical pretreatment before filtration.

System Performance
    The  facility uses two 7-square foot Oberlin pressure
filters (model HB) to remove suspended solids from waste-
water. These two units are in two different locations  1/4-
mile apart. A single treatment unit processes 350  to  400
gallons per hour in a cycle time of 15 to 20 minutes. The  two
units operate at a blowdown time of less than 5 minutes with
an  airbag pressure  of 120 psi.. Each  filtration unit uses
Tyvek®T-980 as the filter media.
    Diatomaceous earth (Superaid) is used as a filter aid.
Agglomeration is  promoted  with a polymer flocculent
(Praestol K122L) at a dosage of 50 ppm in one unit and 300
ppm in the other, depending on the type of waste each unit
treats.  Both the filter aid and polymer flocculent are added
automatically in-line to the filters.

    The effluent streams from the pressure filtration treat-
ment units satisfy Los Angeles sewer effluent limits of 5.0
ppm for soluble lead and 26.0 ppm total suspended solids.
Typical effluent characteristics are 0.2 to 0.4 ppm soluble
lead and 5 ppm total suspended solids. The effluent concen-
trations of other metals are unknown.

    The moisture content of the filter cake is approximately
50 percent.  The filter cake is  classified as hazardous waste
because it does not meet TCLP test requirements. Therefore,
it is disposed of in a hazardous waste landfill.  DuPont plans
to use ProFix in lieu of diatomaceous earth to eliminate off-
site stabilization and reduce operating costs.

Costs
    Operating  costs are related primarily to  filtration sup-
plies. The monthly costs of Superaid, K122L polymer, and
Tyvek® T-980 are  $150, $20, and  $50, respectively.  The
systems require approximately 1 to 2 hours of operator time
per day, including equipment cleaning.

    Maintenance costs are very low. In 5 years of operation,
the two systems experienced no major downtime or repair
requirements.
                                                       52

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Agency
                                      Cincinnati OH 45268
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