United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-87/057 Nov 1987
Project Summary
Waste Minimization Audit Report:
Case Studies of Minimization of
Solvent Waste from Parts
Cleaning and from Electronic
Capacitor Manufacturing
Operations
To promote waste minimization
activities in accordance with the national
policy objectives established under the
1984 Hazardous and Solid Waste
Amendments to the Resource Conser-
vation and Recovery Act of 1976
(RCRA), the Hazardous Waste En-
gineering Research Laboratory (HWERL)
of the USEPA Office of Research and
Development has undertaken a project
to develop and test a waste minimization
(WM) audit procedure.
As part of this project, a total of 6
WM audits were carried out in four
separate facilities. This report presents
the results of an on-site WM audit per-
formed at an electronic capacitor
manufacturing facility for solvent
wastes. The report also describes the
WM audit procedure as it has developed
from the initial (pre-project) sequence
of steps, to the modified (post-project)
sequence that reflects the experience
gained during this HWERL project.
This Prefect Summary was developed
by EPA's Hazardous Waste Engineering
Research Laboratory, Cincinnati, OH, to
announce key findings ot the research
project that Is fully documented In a
separate report of the same title (see
Project Report ordering Information at
back).
Introduction
To promote waste minimization activi-
ties in accordance with the national policy
objectives established under the 1984
Hazardous and Solid Waste Amendments
to the Resource Conservation and Re-
covery Act of 1976 (RCRA), the Hazardous
Waste Engineering Research Laboratory
(HWERL) of the USEPA Office of Research
and Development has undertaken a pro-
ject to develop and test a waste minimiza-
tion (WM) audit procedure.
As part of this project, a total of 6 WM
audits were earned out in four separate
facilities. The full report presents the
results of the on-site WM audits per-
formed at two facilities that generate
solvent-bearing wastes. It also describes
the WM audit procedure as it has
developed from the initial (pre-project)
sequence of steps, to the modified (post-
project) sequence that reflects the ex-
perience gained during this project The
4 other audits, 2 dealing with cyanide
wastes and 2 dealing with heavy metal
and corrosives wastes, are discussed in
two separate reports.
Waste Minimization Audit
Procedure
The main objective of the full report is
to provide useful guidelines for the con-
duct of a WM audit. The following sections
discuss how a WM audit fits into an
overall WM program and provide brief
descriptions of the principal elements of
a WM audit.
The Role of the WM Audit
In a WM Program
The primary objective of a waste
minimization program is to reduce the
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quantity and/or toxicity of waste effluents
leaving the production process. The es-
sential elements of a WM program include
the initiation and planning of the program,
the planning and execution of a WM
audit, and the implementation of the
recommended measures that emerge from
the audit process.
During the program initiation phase,
the commitment of top management to
reduce waste generation must be estab-
lished, which results in the development
of an organizational structure for the WM
program and in the setting of waste
reduction goals for the entire organization.
The next step involves characterization of
waste generation rates and waste char-
acteristics. The program planning step
follows, with the selection of the audit
team(s) to carry out the actual auditing
phase. The auditing process constitutes
the most important element of the overall
WM program, since it provides the key
inputs for the generation of WM options,
as well as for the decisions of which
waste minimization measures should be
implemented. Following the audit, selec-
tion of options for implementation are
made based on feasibility analysis. Finally,
WM measures go through the sequence
of design, procurement, construction,
startup, and performance monitoring.
Waste Minimization Audit
Procedure
The execution of a waste minimization
audit can be divided into three distinct
phases, as shown in Table 1. The overall
objective of the pre-audit phase is to
gather and analyze the information
necessary to select a waste stream(s) for
the facility audit. The audit phase follows,
the objective of which is to develop a
comprehensive set of WM options and to
screen them. The product of the audit
phase is a list of options selected for
further evaluation. A technical and
economic feasibility analysis is performed
for each selected option during the post-
audit phase of the program. This phase
ends with the preparation of a final report.
The following paragraphs provide a brief
description of each audit step.
1. Preparation for the audit
The objective of this step is to gain
background information about the facility
to be audited. Preparation should include
examination of information sources re-
lated to the processes, operations, and
waste management practices at the
facility. The result of proper preparation
should be a well-defined needs list, in-
Table 1. Recommended Waste Minimization Audit Procedure
Activities
Program
Phase
Product
Pre-Audit 1. Preparation for the audit
2. Pre-audit meeting and inspection
3. Data compilation and waste
stream selection
Audit 4. Facility inspection
5. Generation of a comprehensive
set of WM options
6. Options evaluation
7. Selection of options for feasibility
analyses
Post-Audit 8. Technical and economic feasibility
analysis
9. Final report preparation
• needs list/inspection agenda
• notes
• facility and process description
• waste description
• rationale for selection
• notes
• list of proposed options with written
rationale
• independent options ratings by audit
team and by plant personnel
followed by joint review
• list of selected options
• options interim report
• study or budget grade estimates of
capital and operating costs;
profitability analysis
• final report with recommendations
spection agenda, or a checklist detailing
what is to be accomplished, what ques-
tions or issues need to be resolved, and
what information needs to be gathered.
The needs list should be provided to the
facility before the actual site visit to allow
the facility personnel to assemble the
materials needed by the audit team in
advance.
2. Pre-audit meeting
The next step is a pre-audit meeting
with plant personnel. This initial contact
should include solicitation of plant per-
sonnels' views on the focus and function
of the audit. The information needs
identified in the previous step should be
discussed. A tour of the facility should be
performed to familiarize the audit team
with the operations performed. During
this meeting, it is important to establish a
key facility contact.
3. Data compilation and waste
stream selection
Selecting the principal waste streams
or waste producing operations for the
audit provides the audit team with the
focus for the effort. The criteria used for
waste stream selection include waste
composition, quantities, degree of hazard,
method and cost of disposal, perceived
potential for minimization, and compliance
status.
After all pertinent data are collected,
they should be assembled in the form of
a written facility description. The descrip-
tion should include facility location and
size, description of pertinent operations
or processes, and a description of the
waste streams centering on sources,
generation rates, and current methods of
management. The report should include
a written justification for selection of a
waste stream(s) for study.
4. Audit inspection
The audit inspection is the ultimate
step in the information gathering process.
The governing objective of this step is to
evolve a fuller understanding of primary
and secondary causes of waste generation
for the selected waste streams, and to
cover the items missed in the pre-audit
phase. The audit inspection must result
in a clear understanding of waste gen-
eration causes. Useful guidelines for this
step include having a detailed inspection
agenda ready in advance, scheduling the
inspection to coincide with the particular
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operation that is of interest, obtaining
permission to interview plant personnel
directly, obtaining permission to photo-
graph the facility, observing the "house-
keeping" aspects of operation, and
assessing the level of coordination of
environmental activities between various
departments.
5. Generation of WM options
The objective of this step is to generate
a comprehensive set of WM options. It is
important at this point to list as large a
number of options as possible, including
WM measures currently in place in the
audited facility. Option generation should
follow a hierarchy to reflect the environ-
mental desirability of source reduction
over recycling, and of recycling over
treatment. Options can be generated by
examining the technical literature,
through discussion with manufacturers
of equipment or suppliers of process input
materials, and through the use of a
checklist. Table 2 provides a checklist
suitable for solvent wastes.
6. Options evaluation
Each of the options postulated in the
preceding step must undergo a prelimi-
nary qualitative evaluation. The objective
of this evaluation is to weed out the
measures that do not merit additional
consideration and to rank the remaining
measures in the order of their overall
desirability. The evaluation should con-
sider aspects such as waste reduction
effectiveness, extent of current use in the
facility, industrial precedent, technical
soundness, cost, effect on product quality,
effect on plant operations, implementation
period, and implementation resources
availability. It is recommended that the
evaluation process be performed inde-
pendently by both the audit team and the
host facility personnel. A rating system
has been developed to rank the measures
in a consistent pattern and to provide a
framework for resolving the differences
in opinions.
7. Selection of options for
feasibility analysis
Following the evaluation process by
the two independent groups, the two sets
of ratings are compared and discussed in
a joint meeting in order to develop ratings
which are mutually acceptable. The pro-
duct of this meeting is a WM options list
with revised ratings. The final ratings are
then used as a basis for the selection of
options for additional feasibility analysis.
The number of measures promoted to the
feasibility evaluation stage depends on
the time, budget, and resources available
for such study.
8. Analysis of technical and
economic feasibility
The specific WM options selected for
additional evaluation must be analyzed.
Study-grade (e.g., ±30% accuracy) esti-
mates for the capital and operating costs
can be obtained from preliminary vendor
information or factored estimation tech-
niques. Once the costs are obtained, the
analysis is focused on an estimation of
profitability, based on conventional
methods (payback period, internal rate of
return, or net present value).
9. Final report preparation
As the concluding step of a WM audit,
a final report should be prepared to
summarize all the pertinent data, results,
and recommendations.
Results of Waste Minimization
Audits for Solvent Wastes
Waste minimization audits were con-
ducted at two facilities generating
solvent-bearing wastes. The following is
a summary of the reports prepared for
each facility.
Facility S-1A/B
Facility S-1A/B, located in Southern
California, is a major aviation, industrial,
and seaport complex supporting anti-
Table 2. Source Reduction Options Checklist for Solvent Wastes
General Options
Alternate cleaning agents
Alternate paint stripping agents
Equipment cleaning
Dedication
Quality control
Mechanical cleaning
Inert blanketing
Equipment modification
Bag filters
Metal mesh filters
Clean-in-place systems
Waste handling
Segregation
Standardization
Reuse
Recycling
Heat Recovery
Comments
— Possible replacements include steam and alkaline cleaners.
— Possible replacements include caustic, cryogenics, abrasives, and thermal paint stripping
methods.
— Uncontrolled use of solvent for cleaning can be a major waste generator.
— Reduces the need for equipment cleaning between batches of product.
— Reduces the generation of off-spec batches. Equipment that produces off-spec material must
be cleaned before it can be reused.
— Use of wipers to remove deposits from tank walls can reduce the need for cleaning with
solvent. Pipelines can be "pigged" before flushing.
— Prevents the drying of materials inside the equipment.
— Can reduce the need for cleaning or reduce the waste volumes produced.
— Retain less material than cartridge filters. Can be cleaned and reused.
— Can be back-washed during system flush thereby generating no filter waste.
— Often designed to recycle cleaning agent. High pressure spray systems often eliminate the
need for using solvents to remove heavy deposits.
— Proper handling is crucial to the success of recycling solvent waste.
— Increases the likelihood that a solvent waste can be successfully recycled.
— Increases the amount of recyclable waste thereby improving the economics.
— Dirty solvent can often be reused in less critical cleaning operations or be used as pan of the
product formulation.
— Requires the use of a continuous or batch still.
— Many solvents can be used as fuel in industrial boilers/furnaces.
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Options for Cold Cleaning Tanks
Tank location
Tank lids
Removable
Hinged
Roll type
Water seal
Tank vents
Parts handling
Precleaning inspection
Entrance/exit speed
Pan drainage
Rack maintenance
Cleaning efficiency
Degree of agitation
Two-step counter-current sequence
Emulsifiers
Vapor degreaser
Options for Vapor Degreasers
Operation
Heat input
Cooling water temperature
Pans spraying
Overloading
Maintenance
Leaks
Water separator
Stabilizer level
Cross-contamination
Sludge removal
Solvent recovery
Modification
Freeboard height
Freeboard chillers
Silhouette entries
— Tanks near heat sources or drafts can exhibit large evaporative losses.
— Frequent use reduces evaporative losses.
— Seldom used if heavy.
— Often used. Piston effect can cause emissions.
— Best. Disturbs vapor zone least.
— Used with chlorinated solvent. Water quality should be routinely monitored.
— Excessive use increases emissions. Flow rate should be less than SO cfm/ft2.
— Proper handling can extend solvent life and reduce losses.
— Pans should be relatively dry. Excessive water can lead to acid formation when chlorinated
solvents are used.
— Avoid speeds greater than 11 feet per minute to avoid drag-out of vapor.
— Pans should be properly racked so that solvent drains freely.
— Cracks can drag-out solvent and corrosion can contaminate the solvent.
— The greater the efficiency, the more pans cleaned per volume of solvent.
— Can be increased by installing a pump/jet. a mixer, or an ultrasonic unit.
— Allows a higher degree of spent solvent contamination to be reached.
— Provides additional cleaning action by dissolving grease and soil.
— Can clean at much higher contamination levels than can cold cleaning tanks and provides a
much better cleaning action.
If too high, will increase solvent loss to the atmosphere.
Solvent vapor will not be recovered if too high and undue condensation of moisture from the
atmosphere will occur if too low.
Spraying pans above the vapor line bypasses the emission control equipment.
Overloading coHaspes the vapor zone which causes air to be drawn into the unit. Solvent loss
occurs as the zone reforms and the air is expelled.
Cooling coil/steam leaks can introduce excessive water into the unit.
Failure to routinely purge (remove water) can lead to acid formation.
Stabilizers are added to chlorinated solvent to prevent acid formation.
Trace amounts of different solvents can lead to acid formation.
Routine removal reduces the amount of solvent absorbed by the sludge and the potential for
acid formation.
Vapor degreasers can be operated as a still to recover solvent.
Increased height can reduce solvent vapor loss due to turbulence/drafts.
Can be used to create a blanket of cold air which suppresses vapor loss.
Reduce the open area of the unit thereby reducing vapor loss.
submarine aircraft, helicopters, and air-
craft carriers of the Pacific Fleet. Facility
S-1A operations are mostly performed by
military personnel, while facility S-1B
operations are performed by civilians.
There are over 100 solvent end use
points in the entire base. Solvent is used
in many servicing operations, especially
parts degreasing and paint stripping. Due
to the magnitude and diverse nature of
the operations performed, four stations
were selected from the ten initially audited
for a detailed analysis. The stations
selected were Station #1 - Cold Cleaning
Tank, Station #4 - Ball Bearing Cleaning,
Station #6 - Vapor Degreasing, and
Station #7 - Epoxy Paint Stripping. These
stations represent a fair cross-section of
the types of activities that occur at the
base.
For the four stations selected, a total of
36 source reduction options were con-
sidered. Several of these options were
then selected for further investigation,
based on their high future reduction
index. Additional information was ob-
tained from further searches of the avail-
able literature and from contact with
equipment vendors. The measures evalu-
ated in detail included: use of a closed
tank and increasing the cleaning efficiency
of Station #1 by increasing the degree of
agitation; increasing the cleaning effici-
ency of Station #4 by employing a two-
step counter-current cleaning sequence;
reclaiming solvent from spent 1,1,1-TCE
at Station #6 by using the degreaser as a
still; and continuous filtering of stripper
solution at Station #7 (see Table 3).
Measures that involved changes in oper-
ating procedures only were not considered
for additional analysis.
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Tab/* 3. Summary of Source Control Options Investigated for Facility S-1
Control
Station Method
Waste Reduction
Capital
(gal/yr) Cost
Savings Payback
Closed
Tank (d)
Increased
Agitation
75(37) 495 $2,910 $ 360 8.1 Years
620 (a)
4
6
7
Counter-
Current
Cleaning
Level
Alarm
Sludge
Removal
50(33)
62(40-50)
50(64)
300
246
364
$ 600
$ 600
$6,820
$ 220
380 (a)
$ 980 (b)
$2,770
2.7 Years
1.6 Years
7 Months
3.0 Years
(a) Assumes no credit for the waste solvent.
(b) Excludes savings due to reduced disposal costs.
(c) Quantity in parentheses represents percent reduction in virgin solvent use.
(d) Modification of the existing tank would not be viable.
Facility S-2
Facility S-2, located in Southern Cali-
fornia, is a major manufacturer of multi-
layer ceramic capacitors used primarily
by the telecommunications and military
electronics industries. Production opera-
tions are performed in two separate
buildings located within close proximity
to each other. Ceramic materials are
formulated in the Annex Building and
then transferred to the Main Facility
where the capacitors are formed. Various
finishing operations are performed at both
buildings.
The major solvent waste generating
operations audited at the facility include:
cleaning of ball mills, slurry transfer pots,
and slurry application systems with RM-
513 (a proprietary solvent) and recycled
1,1,1-Trichloroethane (TCA); general
cleaning with isopropyl alcohol (IPA) and
recycled TCA; and the on-site recovery of
spent TCA (see Table 4).
A total of 22 options were initially
postulated for the reduction of solvent-
bearing waste from the audited opera-
tions. Following discussions with facility
personnel, seven of the options were
selected for further investigation based
on their high future reduction index.
Additional information was obtained from
further searches of the available literature
and from contact with equipment vendors.
The options evaluated in further detail
include segregate and recycle RM-513
based off-spec slurry, segregate, stan-
dardize, and recycle cleaning solvents,
segregate and recycle RM-513 flushing
solvent, convert application system filters
to bag/wire mesh type, segregate and
recycle isopropyl alcohol waste, and
install secondary recovery system for TCA
primary recovery waste.
Observations and
Recommendations
The following observations and recom-
mendations were made as the result of
the pilot audits:
• For one of the two facilities audited,
the availability of the required pro-
cess documentation was not satis-
factory. Experience with these and
other sites indicated that the avail-
ability and quality of the information
varies significantly. Much informa-
tion is available, however, from out-
side sources such as vendors,
chemical suppliers, and literature.
Tab/* 4. Summary of Solvent Waste Minimization Options Investigated for Facility S-2
Waste Source
Ball Mills and Transfer Pots
Minimization Option
Segregate and recycle RM-513 wastes.
Standardize solvent used and recycle.
Waste Reduction
gallons/year percent
720(a)
2.15O(a)
28.8
86.O
Net Annual
Savings(f)
$6,040
$19,130
Capital
Costs
$25,750
$25,750
Payback
Yearsfgf
4.3
1.3
Slurry Application Systems
General Cleaning With
Isopropyl Alcohol
TCA Primary Recovery
All Waste Sources Shown
Above
Segregate and recycle cleaning waste. 725(c)
Use bag type filters. —
Use metal mesh type filters. —
Segregate and recycle cleaning waste. 2,350
Install a secondary recovery system. 2,015(b)
Use a common batch still for above methods. 5,810
96,7
90.0(d)
lOO.O(e)
$5.400
$1,260
$6,660
$25,750
$23,950
$9,830
SO.Ofd) $11.650 $25.750
73.3 $7.100 $25.750
54.3 $30,190 $25.750
4.8
19.0
1.5
2.2
3.6
0.9
(a) Based on waste volumes before solidification.
(b) Based on the volume of waste shipped off-site for treatment.
(c) See notes (a) and(b) above.
(d) Assumed value.
(e) Filters would be backwashed with the flush solvent so that no additional solvent would be required for cleaning.
(f) Net annual savings is the difference between the actual savings due to reduced raw material and disposal costs and the operating and
maintenance costs.
(g) Payback period equals the capital cost divided by the annual savings. The payback period does not account for depreciation.
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Pre-audit activities, particularly the
pre-audit site visits, were found to
be extremely important in facilitating
the audit process. Cooperation by
the plant staff was improved when
the audit team spent more time
getting to know the host facility staff
and how their organization func-
tioned.
Participation in the options ratings
process is much improved when the
host facility personnel are required
to independently develop ratings of
each of the WM options under
consideration.
Good operating practices recom-
mendations must be presented with
their economic dimension stressed
in order to retain the interest of the
host facility personnel. Otherwise,
they can be seen as trivial and trite.
This report was prepared by staff of Jacobs Engineering. Pasadena. CA 91101.
Harry Freeman is the EPA Project Officer (see below).
The complete report, entitled "Waste Minimization A udit Report: Case Studies
of Minimization of Solvent Waste from Parts Cleaning and from Electronic
Capacitor Manufacturing Operations," (Order No. PB 87-227 013/AS: Cost:
$18.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Officer can be contacted at:
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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