PB88-166780
WASTE MINIMIZATION AUDIT REPORT:
CASE STUDIES OF MINIMIZATION OF
SOLVENT WASTES <\ND ELECTROPLATING
WASTES AT A OO'J INSTALLATION
Versa r, in c o r porate d
S p r i n g f i e 1 d , V A
Feb 88
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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PB88-166780
EPA/600/2-88/010
February 1988
WASTE MINIMIZATION AUDIT REPORT
Case Studies of Minimization of Solvent Wastes
and Electroplating Wastes at a DOD Installation
By:
Marvin Drabkin and Paul Sylvestri
Versar Inc.
Springfield, Virginia 22151
EPA Contract No. 68-01-7053
Work Assignment No. 85
Project Officer
Mr. Harry Freeman
Hazardous Waste Environmental Research Laboratory
Cincinnati, Ohio 45268
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT.
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
REPRODUCED BY
U.S. DEPARTMENT OF COMMERCE
NATIONAL TECHNICAL
INFORMATION SERVICE
SPRINGFIELD. VA 22161
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TECHNICAL REPORT DATA
(flease read Instructions on the reverse before completing)
1. REPORT NO.
EPA/600/2-88/010
2.
3. RE
4. TITLE AND SUBTITLE
WASTE MINIMIZATION AUDIT REPORT Case Studies of
Minimization of Solvent Wastes and Electroplating
Wastes at a DOD Installation
7. AUTHOR(S)
M. Drabkin and P. Sylvestri
5. REPORT DATE
February 1988
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Versar, Inc.
Springfield, VA 22151
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
-'"The report results of a waste minimization audit carried out in 1987 at a tank
reconditioning facility operated by the DOD. The audit team developed
recommendations for reducing the generation F006 wastewater treatment sludge, and
F002, and F004 solvent wastes. In addition to detailing recommendations for the
subject streams the report outlines the US EPA recommended procedure for conducting
waste minimization
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (Tliil Report)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
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Notice
This report has been reviewed by the U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
11
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Foreword
The term, "waste minimization," is heard increasingly at meetings and
conferences of individuals working in the field of hazardous waste
management. Waste minimization is an umbrella term that includes the
first four categories of the EPA's preferred hazardous waste management
strategy which is shown below:
1. Waste Reduction: Reduce the amount of waste at the source,
through changes in industrial processes.
2. Waste Separation and Concentration: Isolate wastes from mixtures
in which they occur.
3. Waste Exchange: Transfer wastes through clearinghouses so that
they can be recycled in industrial processes.
4. Energy/Material Recovery: Reuse and recycle wastes for the
original or some other purpose, such as for materials recovery
or energy production.
5. Incineration/Treatment: Destroy, detoxify, and neutralize wastes
into less harmful substances.
6. Secure Land Disposal: Deposit wastes on land using volume
reduction, encapsulation, leachate containment, monitoring, and
controlled air and surface/subsurface water releases.
In general, the idea underlying the promotion of waste minimization is
that it makes far more sense for a generator not to produce waste rather
than develop extensive treatment schemes to insure that the waste stream
poses no threat to the quality of the environment.
In carrying out its program to encourage the adoption of waste
.minimization, the Hazardous Waste Engineering Research Laboratory has
supported a program to carry out waste minimization audits in a wide
variety of industrial settings. This report contains the results of
several such audits carried out to reduce the generation of cadmium/cyanide
and solvent wastes. It will be useful to individuals interested in
identifying opportunities for reducing those waste streams.
If further information, please contact the Alternative Technologies
Division of the Hazardous Waste Engineering Research Laboratory.
Thomas R. Hauser
Director
Hazardous Waste Engineering Research Laboratory
111
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ABSTRACT
The U.S. Environmental Protection Agency is encouraging hazardous
waste generators to develop programs to reduce the generation of
hazardous waste. To foster such programs, the Agency's Office of
Research and Development Hazardous Waste Engineering Research Laboratory
(ORD/HWERL) is supporting the development and evaluation of a model
hazardous waste minimization audit (WMA) procedure using the EPA
hierarchy of waste minimization (WM) options, with source reduction being
more desirable and recycle/reuse less desirable. Treatment options,
although not considered WM, were evaluated if neither of the former
alternatives was available. The WMA procedure was tested initially in
several facilities in 1986. WMAs were conducted at generators of a
number of generic hazardous wastes, including corrosives, heavy metals,
spent solvents, and cyanides.
In 1987, the HWERL WMA program has concentrated on ORD's top priority
RCRA K and F waste list. Audits were conducted at generators of K071 and
K106 wastes (mercury cell chloralkali plants), K048-K052 wastes (sludges
and solids from petroleum refining), F002-F004 wastes (spent solvents),
and F006 wastes (wastewater treatment sludges from electroplating
operations). The present report covers a WMA carried out at a DOD
installation responsible for the rehabilitation of worn Army tanks. This
audit was aimed at developing WM options for F002, F004, and F006 listed
wastes.
Two source reduction options were developed by the audit team for
F002 and F004 wastes with attractive payback periods and substantial
potential savings in waste solvent disposal costs. A number of source
reduction and recycle/reuse options were developed for the electroplating
wastes which, if successfully implemented, could result in substantial
savings in F006 waste disposal costs as well as achieve compliance with
the DOD installation's NPDES permit limitations for cadmium and cyanide.
iv
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CONTENTS
Page
Notice of Disclaimer ii
Foreward i i i
Abstract i v
Table of Contents v
Figures vi i
Tables viii
1. Introduction 1-1
2. Waste Minimization Program 2-1
3. Waste Auditing Methodology 3-1
Preparation for the Audit 3-1
Host Site Pre-Audit Site Visit 3-6
Waste Stream Selection 3-6
Host Site Waste Minimization Audit Visit 3-7
Generation of Waste Minimization Options 3-9.
Preliminary Evaluation and Rating of Options 3-12
Presentation and Joint Review of Options with
Plant Personnel 3-13
Final Audit Report 3-15
Waste Auditing - Some Do's and Don'ts 3-15
4. Listed Waste F006 - Waste Minimization Audit Case
Study 4-1
Facility Description 4-1
Equipment Layout Description 4-2
Process Description 4-11
Waste Stream Description 4-19
Current Waste Management Profile 4-20
Postulated Waste Minimization Options 4-23
Projected Costs for the Proposed WM Options 4-29
Summary and Discussion 4-32
5. Listed Wastes F002 and F004 - WMA Case Studies 5-1
Facility Description 5-1
Equipment Layout Description 5-1
Process Description 5-6
Waste Stream Description 5-8
Current Waste Management Profile 5-9
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CONTENTS (continued)
Page
Postulated Waste Minimization Options 5-10
Projected Costs and Site Area Requirements
for the Proposed Waste Minimization Options 5-13
Summary and Discussion 5-16
6. References 6-1
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FIGURES
Number Page
1 Components of Waste Minimization, Their Hierarchy, and
Definitions 3-10
2 Elements of Source Reduction 3-11
3 Simplified Schematic: Automatic Barrel Cadium Plating
Line 4-12
4 Simplified Schematic: Manual Cadmium Plating Line 4-15
5 Simplified Schematic: Manual Chromium Plating Line 4-17
6 IWTP Flow Schematic 4-21
7 Production Area Layout and Wastewater Discharge
Schematic for Building 129 , 5-2
8 Production Area Layout and W.nstev/ater Discharge
Schematic for Building 130 5-3
9 Production Area Layout and Wastewater Discharge
Schematic for Building 409 5-4
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TABLES
Number Page
1 Waste Minimization Program Elements 2-3
2 Waste Audit Teams and Resident Support Groups for the
Audits at a DOO Installation Generating Listed Wastes
F006, F002, and F004 2-5
3 Initially Proposed Waste Minimization Audit Procedure ..... 3-2
4 Recommended Waste Minimization Audit Procedure 3-3
5 Waste Minimization Audits - Information Needs List
for Listed Wastes F006, F002, and F004 at a DOD
Installation 3-4
6 Waste Minimization Audits Generalized List
of Information Sources 3-5
7 Summary of Source Control Methodology for the A/3
Powder Formulation Process: Illustration of
Development of Options Ranking 3-14
8 Dimensions, Construction, and Capacity of Major
Cadmium/Chromium Electroplating Line Equipment -
Building 114 '. 4-3
9 Operating Specifications of Major Cadmium/Chromium
Electroplating Line Equipment - Building 114 4-5
10 Dimensions, Construction, and Capacity of Major
Chromium Electroplating Line Equipment - Building 114 4-8
11 Operating Specifications of Major Chromium
Electroplating Line Equipment - Building 114 4-9
12 Tabulated Projected Costs: WM Options for the
DOD Installation F006 Wastes 4-30
vm
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TABLES (continued)
Number Page
13 Paint Stripping Solvent Handling Capacity at the DOD
Installation 5-5
14 Chemical Constituents and Their Ranges of Concentrations
in the Paint Stripping Solvents Used at the DOD
Installation 5-6
15 Ingredients and Usage Locations of Paint Stripping
Solvents Used at the DOD Installation 5-7
16 Tabulated Projected Costs and Required Site
Modifications: WM Options for DOD Installation
F002 and F004 wastes 5-14
IX
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SECTION 1
INTRODUCTION
The national policy objectives established under the 1984 Hazardous
and Solid Waste Amendments to the Resource Conservation and Recovery Act
of 1976 include the goal of reducing or eliminating hazardous waste as
expeditiously as possible. To promote waste minimization activities, the
Hazardous Waste Engineering Research Laboratory (HWERL) of the U.S.
Environmental Protection Agency (EPA), Office of Research and Development,
has undertaken a project to develop and test a waste minimization audit
(WMA) procedure. It is envisioned that such a procedure would be useful
to generators of hazardous waste as they search for waste minimization
alternatives.
A number of authors have recognized the potential value and
desirability of conducting waste audits, although they have suggested
differing approaches and scope "limits for such audit activities (U.S.
Congress 1986, USEPA 1986a, Fromm and Callahan 1986, Pojasek 1986, Kahane
1986, League of Women Voters, Mass. 1986). This HWERL project expands on
a recently developed and tested audit procedure (EPA 1987, EPA 1987a, EPA
1987b) by conducting actual WMAs in cooperating industrial and government
facilities. The present project includes an audit at a DOD installation,
and is one of several current audit efforts being supported by HWERL.
Section 2 of this report presents the elements of an overall waste
minimization program, of which the audit procedure is an important
component. Section 3 describes the WMA procedure, its development, and
its final recommended form. Section 4 presents the results of a WMA
performed at a DOD installation with a facility that generates listed
waste F006. Section 5 contains the results of a WMA performed at the same
installation with a facility that generates listed wastes F002 and F004.
Conclusions and recommendations,resulting from these audits are presented
in the respective sections.
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SECTION 2
WASTE MINIMIZATION PROGRAM
Structured programs designed to improve the cost, energy efficiency,
safety, and other environmental aspects of an industrial undertaking are
not a new concept. During World War II, the General Electric Corporation
developed standardized procurement procedures for reducing product cost
without sacrificing functionality. Later, similar procedures were
developed and applied to lower the costs of design and construction
projects. This activity, known as value management, value engineering,
or value analysis, is currently ?. well established government
requirement. In fact, it was mandated by the U.S. EPA for all
construction projects involving wastowater treatment plants. A
subsequent study of 156 treatment plants ihowed that cost reduction
programs saved $95 million, (-.; a 12 to 1 return on investment (Zimmerman
and Hart 1982).
Environmental compliance audits and reviews are also becoming more
common and are acquiring tha status of an industry norm. The primary
objective of an environmental audit is to determine the status of a
corporation's compliance with Federal, State, and local environmental
laws and regulations (Truitt et al. 1983). Additionally, such audits
often can provide information to aid risk assessment and corporate
planning.
Energy conservation audits are performed to reduce energy consumption
per unit production. It was estimated that energy audits helped save
chemical process industries about $1 billion between 1974 and 1979
(Parkinson 1979). Other related structured programs include safety
reviews, hazard analyses, or failure mode and effects analyses. Waste
minimization programs can be considered to be in the same category as
these programs.
The principal objective of a waste minimization (WM) program is to
reduce the quantity and/or toxicity of waste effluents leaving the
production process in a manner consistent with the goals of protecting
human health and environment. Unlike environmental audit programs, a WM
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program does not seek to determine or improve the regulatory compliance
status of a facility. Rather, it is primarily oriented toward producing
a set of effective measures to reduce waste generation.
Table 1 presents a breakdown of WM program elements. In the context
of an overall WM program, the waste auditing process (composed of
pre-audit, audit, and post-audit phases) follows the program
initiation/planning phase. During this initiation/planning phase, the
commitment of top management, to reduce waste generation must first be
established. This is often done with a formal directive signed by the
chief executive officer of the firm or an administrator of a government
organization. The organizational commitment to start a WM program is
often associated with a goal setting process, e.g., duPont is currently
implementing an annual 5 percent waste reduction goal.
A corporate WM program may be organized in a typical pyramid
structure, with command and monitoring functions centered at the
corporate level and implementation responsibility totally delegated to
individual plants. A corporate-level independent expert task force may
be formed to assist individual plants in setting up and executing their
own WM programs.
At the plant level, the WM program may follow the scheme successfully
used at Union Carbide for energy conservation efforts. At Union Carbide
plants, a plant program coordinator is appointed and supported by a
committee. The coordinator then selects and oversees individuals in each
department who are responsible for devising and/or carrying out WM
activities in their departments (Williams 1976).
This program planning phase should include the selection of audit
teams to carry out the next program phase. The audit team leader should
have a strong technical background, demonstrated problem solving ability,
and, if possible, experience associated with the relevant process(es).
In addition, the leader should possess strong management and
communication skills. It would be preferable for the leader, or at least
some members of the audit team, to have no previous association with the
plant, so as to bring a fresh and unbiased perspective to the audit
process. Such outsiders can be independent consultants or qualified
personnel from other plants.
The audit team must have access to all required documentation and to
a wide variety of plant personnel. During a recent internal workshop on
waste minimization conducted by a major U.S. corporation, the
participants (mostly environmental affairs managers at individual plants)
were asked who should provide support to a waste audit team. The
following responses were obtained:
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Table 1. Waste Minimization Program Elements
Program phase
Job plan* phase
Elements
I. Initiation/
Planning
II. Pre-Audit
III. Audit
IV. Post-Audit
V. Implementation
Information
Creative
Judgment
Development
Recommendation
Secure commitment/authority
Establish goals
Establish organization
Preparation for the audit
Pre-audit inspection
Waste stream selection
Facility inspection
Generate comprehensive
set of WM options
Options evaluation
Selection of options
for feasibility
analysis
Technical and economic
feasibility analysis
Report preparation
Selection of options for
implementation
Design, procurement,
construction
Startup
Performance monitoring
* Term adopted from value management program.
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Raw material suppliers;
QA/QC department;
Outside consultants;
Customer representatives;
Process engineer;
Safety engineer;
Materials engineer;
Foreman;
Plant manager; and
Purchasing agent.
In short, the organization should be prepared to provide the audit
team with access to a wide range of people both inside and outside the
firm. The teams that carried out the audits described in this report
were composed entirely of employees from outside consulting/engineering
firms. Table 2 depicts the composition of the outside audit teams and
the resident support groups.
The waste minimization auditing process (Table 1, phases II, III, and
IV), which is described in detail in the next section, provides the key
input to the implementation phase of the program, i.e., recommendations
on which WM measures are to be implemented. Once a decision is made to
proceed with the implementation of a specific WM measure, subsequent
activities follow a well established, conventional pattern. Detailed
design follows preliminary design; the procurement effort proceeds from
inquiry and definitive bids to bid analysis and the expediting stages;
and construction advances along the path determined by a detailed
schedule and budget. The budget is controlled through estimates of cost
performed at various project stages; accuracy increases as material and
labor requirements become better defined. Startup follows mechanical
completion. Finally, to ascertain the effectiveness of the changes made,
ongoing performance monitoring is undertaken.
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Table 2. Waste Audit Teams and Resident Support
Groups for the Audits at a DOD Installation
Generating Listed Wastes F006, F002, and F004
1. Outside Audit Team
Chemical engineer*, Ph.D., 37 yrs of experience, audit team leader
Chemical engineer, B.S., 4 yrs of experience
Independent consultant*, 45 yrs of experience in the metal
finishing industry
2. Resident Support Team
Plant environmental engineer
Plant process engineer
Facility supervisors
U.S. Army Pentagon Environmental Office engineers
* Technical support and review function only.
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SECTION 3
WASTE AUDITING METHODOLOGY
As was shown in Table 1, waste minimization audits are a central
feature of a WM program. The auditing process is subdivided into
pre-audit, audit, and post-audit phases. The recommended sequence of
steps shown in Table 1 (also shown in expanded form in Table 4), is based
on modifications of the originally proposed sequence, which is presented
in Table 3. Modifications were made to reflect the experience and
insights gained as a result of actual audit work. The following sections
detail each of the eight sequential steps of the recommended waste
minimization audit (WMA) procedure shown in Table 4.
PREPARATION FOR THE AUDIT
The objective of this activity is to gain background information
about the facility to be audited. Preparation should include examination
of literature references related to the activities performed at the
facility, such as EPA background documents on the industries involved,
plant permit applications, and other relevant documents pertaining to
waste discharge at the industrial facilities of interest. Proper
preparation should result in a well-defined needs list, inspection
agenda, or a checklist detailing what is to be accomplished, what
questions or issues need to be resolved, and what information should be
gathered.
For the host site audited in this report, the needs list (Table 5)
was provided to the resident support team in advance of the site visit.
This was very important in ensuring the success (and efficiency) of the
site visit, since it provided time for the facility personnel to assemble
the materials required by the audit team prior to its visit. A more
generalized list of documents and information sources is given in Table 6.
In the audits of the facilities reported herein, the availability of
the required process documentation was excellent. This documentation
proved to be invaluable in enabling the audit team to establish a set of
waste minimization options.
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Table 3. Initially Proposed Waste Minimization
Audit Procedure
Job plan element
Step
Information phase
Creative phase
Judgment phase
Development phase
Recommendation phase
1. Preparation for inspection
2. Facility inspection
3. Process and waste stream description
4. Generation of WM options
5. Preliminary evaluation and ranking
of options
6. Presentation, discussion, and joint
review of options with plant
personnel
7. Selection of options for
feasibility analysis
8. Technical and economic feasibility
analysis
9. Final report preparation
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Table 4. Recommended Waste Minimization Audit Procedure
Program phase
Activities
Product
Pre-Audit
1. Preparation for the audit
2. Pre-audit meeting and
inspection
3. Waste stream selection
needs list/
inspection agenda
notes
process description
waste descripton
with rationale for
selection
Audit
4. Audit inspection
5. Generation of a compre-
hensive set of WM options
6. Options evaluation and
selection for feasibility
analysis
notes
list of proposed
options with written
rationale
list of selected
options
options ratings by
audit team and by
plant personnel
options interim
report
Post-Audit
7. Technical and economic
feasibility analysis
8. Final report preparation
study or budget
grade estimates of
capital and
operating costs;
profitability
analysis
final report with
recommendations
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Table 5. Waste Minimization Audits - Information
Needs List for Listed Wastes F006, F002
and F004 at a DOO Installation
1. Process Flow Diagrams (PFDs) with Heat and Material Balances (HMBs)
2. Piping and Instrumentation Diagrams (P&IDs)
3. Plot plan or general arrangement of equipment
4. Process description (process flows, liquid and solid wastes
characterizations)
5. Equipment layouts (plan and elevation views)
6. Quantities and costs of chemicals
7. Dimensions and operating gallonage of all pertinent process vessels
and tankage
8. Quantities and costs of disposal for all wastes (liquid and solid)
9. Process equipment materials of construction
10. History of previous waste management projects and any related
documentation
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Table 6. Waste Minimization Audits Generalized
List of Information Sources
Design process flow diagrams (PFD) with heat and material balances
(HUB) for process and pollution control systems
Equipment list
Piping and instrument diagrams (P&ID)
Materials application diagrams (MAD)
Plot and elevation plans
General arrangement drawings
Piping layout drawings
Operation manuals, process descriptions
Permits and/or permit applications
Emission inventories
Hazardous waste manifests
Annual (or biennial) reports
Waste assays
Operator data logs, batch sheets
Materials purchase orders
Environmental audit/review reports
Production schedules
Organization chart
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Experience with other sites indicates that the availability and
quality of information varies significantly, however. It is important to
allow for this contingency and to have a fall-back position. For
example, if a piping and instrument diagram (P&ID) is not available, it
may be possible to obtain a piping layout plan instead. Similarly, if
the information cannot be obtained from the facility, that does not mean
that it is unavailable elsewhere. Much information is obtainable from
outside vendors, e.g., the costs of bath make-up chemicals or the
physical design of the process equipment. If information is truly
needed, it can be obtained with proper initiative and ingenuity, although
such action may affect project costs and schedules. In light of this
possibility, it is important to seek only that information which is
necessary to understand the process, to allow for delineation of waste
sources and current waste management techniques, and to characterize
waste generation quantitatively. Requesting unnecessary information
burdens both the provider and user (auditor) and slows down the work.
HOST SITE PRE-AUDIT VISIT
The purpose of this meeting is to become familiar with plant
operations and plant personnel. Initial contacts with plant personnel
should include solicitation of their views on the focus and function of
the audit. This will help to identify waste streams of concern to the
facility. The information needs defined in the previous step should be
discussed here and hopefully met. A guided tour of the facility should
be taken.
At this initial visit, the groundwork for a successful working
relationship with facility personnel must be laid. It should be stressed
that a cooperative attitude and active involvement by host facility
personnel are essential to the success of the audit process. The initial
point of contact at the facility (Plant Manager, Environmental
Coordinator, etc.) must be enlisted as a "Product Champion" for the
program before the audit commences. He/she must be encouraged to relay
the message of cooperation and involvement to others at the facility.
WASTE STREAM SELECTION
Suitable waste streams should be selected either following the
initial conference with plant personnel or after the first plant
inspection. Selection should be based on discussions with plant
personnel and on the independent assessment of the project team. The
criteria used to select a waste stream must include at a minimum:
Composition;
Quantity;
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Degree of hazard (toxicity, flammability, corrosivity, and
reactivity);
Method and cost of disposal;
Potential for minimization and recycle; and
Compliance status.
For the two case studies cited in this report, stream selection was
not a problem. Focusing the audits on three particular wastes (listed
wastes F002, F004, and F006) simplified the selection. These are the
principal hazardous wastes generated at the audited DOD installation.
With the selection of the waste streams, the pre-audit stage of the
procedure is completed. At this point, it is recommended that a written
description be prepared of the facility, process (or operation) and of
the waste streams. The description should encompass:
Facility location and size;
Description of operations or processes of concern, including
diagrams necessary to detail the pertinent aspects of waste
generation; and
Waste stream(s) description centering on sources and current
methods of management; this information should be supplemented
with summaries of generation rates, compositions, disposal costs,
and raw material costs, and tne rationale for waste selection
should be provided.
Descriptions of facility, process, and waste stream(s) for the
facilities involved with audits on listed waste F006 are given in
Section 4. Section 5 presents this information as related to listed
wastes F002 and F004. Such descriptions summarize all the pertinent
information acquired.
HOST SITE WASTE MINIMIZATION AUDIT VISIT
In the course of the pre-audit activities, a general understanding of
the process facility operations and, more important, of waste sources was
established. Also, waste stream selection had been finalized (in most
cases) and the information summarized in a written description of the
facility,' process, and waste stream(s).
With the needed comprehension of the process and focus in place, the
audit inspection can now be conducted. Typically, the inspection would
focus on selected aspects of the operation identified through the
pre-audit activities. The governing objective is to obtain a greater
awareness of the principal and secondary causes of waste generation and
to examine the items overlooked in the pre-audit stage.
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The audit inspection is the ultimate step in the information
gathering process. The following guidelines have been formulated as a
result of the work performed on this project:
1. Have an agenda ready. This should cover all points that still
require clarification following the pre-audit phase.
2. Plan on inspection of the various process operations of interest
at different times during the production shift for continuous
processes, in order to observe possible fluctuations in normally
steady-state operations. Expect to monitor operations over a
period of 1 to 2 days.
3. Obtain permission to interview the operators, 8-hour shift
supervisors, and foremen directly. Listen attentively and do not
hesitate to question more than one person if the answer is not
forthcoming. Try to assess the operators' and their supervisors'
awareness of waste generation aspects of the operation. Note
their familiarity (or the lack thereof) with the impacts their
operation may have on other operations, e.g., the effect of
dumping solvent spills into the existing wastewater treatment
plant, rather than metering these solutions at a controlled rate.
4. Obtain permission to photograph the facility. Photographs are
especially valuable in the absence of plan layout drawings. Many
details can be captured in photographs that otherwise could well
be forgotten or inaccurately recalled at a later date.
5. Observe the "housekeeping" aspect of the operation. Check for
signs of spills or leaks. Ask to visit the maintenance shop and
inquire about their problems in maintaining the equipment
leak-free. Assess the overall cleanliness and order of the site.
6. Assess the level of coordination of environmental activities
among various departments.
During the planning stage and the actual audit inspection itself, it
is beneficial to mentally "walk the line" from the suspected source of
waste generation to the point of exit, be it a treatment unit, storage
facility, or haulage to offsite RCRA treatment, storage, and disposal
(TSD) facilities. The audit inspection must result in a clear .
understanding of the causes of waste generation.
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GENERATION OF WM OPTIONS
Thus far, the audit process has been mainly oriented toward
information gathering and organization. These activities should have
yielded a thorough understanding of the origins of waste generation and
of the process or facility operations in general. The audit activity has
now reached the creative phase.
The objective of this step is to generate a comprehensive set of WM
options. Such activity may take the form of a "brainstorming" session
involving audit team members or may involve separate efforts by
individual members. A combination of these approaches was found to be of
value during the audits conducted for this study. In this stage of the
audit process, it is important to generate as many options as possible.
Current WM measures in the audited facility should also be listed. This
knowledge often leads to the formulation of additional options and
provides valuable insights for the option evaluation step to follow.
In generating options, most of the effort should first focus on
source reduction, followed by recycling and then treatment (if there are
no options available in either of the preferred areas). Such a hierarchy
of effort stems from the fact that environmental desirability favors
source reduction over recycling and recycling over treatment.
Current EPA-proposed definitions of waste minimization and key waste
minimization terms are given in Figure 1. A generalized guide map to
various source reduction elements is shown in Figure 2. For a discussion
of the terms and examples illustrating each element, the reader is
referred to the EPA support document for the 1986 Report to Congress on
Waste Minimization (USEPA 1986b).
To develop options, it is often necessary to examine the technical
literature. The reference section of this report lists the sources
consulted for technical material relevant to reduction or elimination of
solvent and cyanide electroplating wastes. Options can also be
formulated through discussion with manufacturers of equipment or
suppliers of process input materials.
The result of the WM options generation step should be a list
identifying each option, together with a brief description of the
rationale for its listing. For the F006 waste studied in this report, a
total of seven relevant options could be determined at the facility
audited, while for the F002 and F004 wastes, a total of four relevant
options were developed at this facility.
3-9
-------
Co
i
WASTE MINIMIZATION
SOURCE REDUCTION
RECYCLING
J
RELATIVE ENVIRONMENTAL DESIRABILITY
GREATER SSSSSSSSSSSSSSS^^
LESSER
ORDER OF EXPLORATION sv.
FIRST SSSSSSSSSSSSSSSSS^^
SECOND
FIGURE 1. COMPONENTS OF WASTE MINIMIZATION, THEIR HIERARCHY AND DEFINITIONS
-------
SOURCE REDUCTION
J
PRODUCT SUBSTITUTION
EXAMPLE:
CONCRETE MARINE PINGS
MSTEAD OF TREATED WOOD
SOURCE CONTROL
CO
I
NOTE: CAN BE EXTERNAL TO
GENERATOR
MPUTUATEMAL CHANGES
oPURTlCATTON
o SUBSTITUTION
o DILUTION
TECHNOLOGY CHANGES
oPROCESS CHANGES
o EOUIPMENT.PPING OR LAYOUT
CHANGES
o CHANGES TO OPERATIONAL
SETTNGS
o ADDITIONAL AUTOMATION
o ENERGY CONSERVATION
o WATER CONSERVATION
PROCEDURAMNSmUTONAL CHANGES
o PROCEDURAL MEASURES
o LOSS PREVENTION
o PERSONNEL PRACTICES
o SEGREGATION
o MATERIAL HANDLING IMPROVEMENTS
Figure 2. Elementsofsourcereduction
-------
PRELIMINARY EVALUATION AND RATING OF OPTIONS
Each of the options postulated in the preceding step must undergo a
preliminary engineering evaluation and rating. The objective of this
evaluation is to eliminate the measures that do not merit additional
consideration and to rank the remaining measures in order relative to
their overall desirability.
The evaluation should include, at a minimum, consideration of the
following aspects:
Waste reduction effectiveness (i.e., reduction of waste quantity
and/or toxicity);
Extent of current use in the facility;
Industrial precedent;
Technical soundness;
Cost (preliminary capital and operating cost evaluation). An
important economic yardstick for option evaluation is the
determination of a "payback period," which is defined here as the
incremental investment divided by the net savings in direct
operating costs resulting from implementation of the proposed
option.
Effect on product quality;
Effect on plant operations;
Implementation period; and
Resources availability and requirement.
The preliminary evaluation and valuing process would consist of the
following steps carried out by the audit team:
\
(a) Developing a written rationale for each proposed option
including a clear description of the operating principle,
estimates of waste minimization measured in pounds of waste and
in pounds of waste per unit production, estimates of potential
resource recovery measured in pounds of waste component
recyclable to the process or salable as a recovered material,
perceived advantages and disadvantages, simplified schematics of
the proposed material flow, material balance calculations,
"order of magnitude" cost estimates, references relating to
prior applications, and other relevant documentation pertaining
to the idea. These steps were carried out as appropriate for
each option developed for minimization of listed wastes F006,
F002, and F004
3-12
-------
(b) Qualitative rating of each option in three categories: waste
reduction effectiveness, extent of current use, and future
application potential. The ratings are to be done on scale of 0
to 10 by a proponent, then reviewed by the audit team leader.
It is expected that some options may receive ratings low enough to
warrant their withdrawal. The team leader may call a review meeting to
submit the ratings to a collective discussion or vote. In the case of
the audits discussed in this report, a number of such options were
withdrawn, as is discussed in Sections 4 and 5.
The product of this effort should be a table summarizing the
preliminary ratings for each option that addresses a particular waste
stream or source, along with the written documentation developed in this
phase of the audit. Table 7 is a sample table illustrating the approach
used to develop such a summary table.
PRESENTATION AND JOINT REVIEW OF OPTIONS WITH PLANT PERSONNEL
Following the technical and economic evaluations of the selected
options by the audit team, these options are prepared in the form of a
Preliminary Audit Report to be submitted to appropriate plant personnel.
Each option in the Preliminary Audit Report should be well described in
terms of the technical rationale and projected "order of magnitude" cost
estimates. Cost estimates are of particular importance to plant.
personnel who have to deal with tight operating budgets and must have
some idea of the cost of implementing an attractive-appearing option. In
this regard, calculation of "the payback period" will provide a quick
indication of the economic viability of the proposed option. Cost
estimates are also of importance to the options belonging to the category
of good operating practices. Availability of preliminary cost data along
with the presentation of this category of option circumvents quick
dismissal of these options as "trivial" by a technology-oriented plant
engineer.
The plant personnel should then be asked to review the Preliminary
Audit Report and independently rate each proposed option, revise them
based on their assessment, and incorporate any additional options they
consider applicable.
The review process would culminate in a joint meeting in which the
audit team would present the proposed options one by one. The
presentation ideally should include a detailed discussion of the
rationale and reasons for selected ratings. The plant engineers would
then present their critique or comments. The discussion should conclude
with a revised rating acceptable to both sides. If such a conclusion
cannot be reached, a further course of action must be well outlined.
3-13
-------
Table 7. Summary of Source Control Methodology for the A/B Powder Formulation
Process: Illustration of Development of Options Ranking
CO
i
Waste
reduction
Waste source
Weighing operation
Wet grind loading
and unloading
Dry grind loading
and unloading
Control methodology effectiveness
1.
2.
3.
1.
2.
3.
4.
5.
6.
7.
8.
9.
1.
2.
3.
4.
5.
Return empty containers
Use preweighed containers
Use drum covers
Overall
Use plastic funnel/collar on unit
Use smaller trays, manual operation
Place trays on rack, walk- in oven
Use elevator table on rack, walk-in even
Install roller conveyer under valve
Install fail-close valve on discharge
Pump slurry into trays over at oven
Reduce cleaning frequency
Bypass dry grinding unit
Overall
Use plastic funnel/collar on unit
Do not load while unit is operating
Inspect all seals regularly
Use drum covers
Bypass dry grinding unit
Overall
2
2
2
2.00
2
2
2
]
1
2
2
3
i
1.89
2
3
2
2
4
2.60
Extent of
current use
0
0
2
0.67
0
0
0
0
0
0
0
0
C
0.00
0
4
3
2
0
1.80
Future
application Fraction of
potential total waste
2
4
1
2.33 0.10
4
2
2
1
1
3
1
3
4
2.33 0.45
4
0
2
3
4
2.60 0.45
Current
reduction
index
0
0
0
0
0
0.
0.
0,
0.
0.
0.
0.
0.
0.
0.
0.
0,
0.
0
0.
.00
.00
.25
.25
.00
.00
,00
.00
.00
.00
.00
.00
.00
.00
.00
75
.38
.25
.00
.75
Future
reduction
index
0.25
0.50
0.06 ,
0.50
0.50
0.25
0.25
0.06
0.06
0.38
0.13
0.56
0.50
0.56
0.50
0.00
0.06
0.19
0.90
0.90
All sources
All methods
1.00
0.58
0.71
-------
The objective of the meeting is to obtain an agreement on the ratings
of various proposed options; these ratings would then be analyzed and
used to rank all the options, with the aim of selecting those that
warrant further evaluation by the plant. It also may happen that the
plant personnel may suggest new options or that such options may result
from the joint discussion.
Following the meeting, all appropriate revisions of the options
presented in the Preliminary Audit Report would be made in preparation
for the issuance of a Final Audit Report.
In the present audit effort, both the audit team and the plant
personnel were in agreement on the evaluation of each of the options
presented.
FINAL AUDIT REPORT
In accordance with the workplan, the Final Audit Report will contain,
at a minimum, the following sections:
1. Facility and process description;
2. Description of waste stream(s) origin, composition, and
quantities;
3. Detailed description of all work minimization options considered,
including simplified schematics of revised process flows (if
appropriate) and lists of any new process equipment required;
4. Detailed evaluation of technical feasibility and potential
benefits of all waste minimization options considered, together
with their preliminary economics (capital and operating costs,
estimated payback period) and final rankings (based on audit team
findings and host plant engineers evaluations); and
5. Recommendations including any research and development efforts
needed to further evaluate the recommended options.
WASTE AUDITING - SOME DO'S AND DON'TS
Some of the most important lessons learned in the pilot audits relate
to the human element of the audit process, i.e., to the interaction
between the audit team and the host facility personnel.
Obviously it is vital that host facility personnel become and remain
active participants throughout the audit process. Some nontechnical
skills of the audit team personnel, and particularly of the audit team
leader, were found to be extremely valuable here.
3-15
-------
The audit team leader must be an effective and aggressive
communicator as well as a technical expert, because this individual must
serve as a facilitator for the audit team and host facility personnel
alike. A reserved and low key attitude and behavioral style by the audit
team could lead to a passive or disinterested stance by the host facility
personnel.
The experience gained in these audits also led to a modification of
the audit method. The modified approach requires host facility personnel
to independently develop ratings for each of the waste reduction options
under consideration. The audit team's ratings for the options and the
host facility's independent ratings can then be reviewed and reconciled
in a group session. The initial approach of having the host facility
personnel merely review and discuss the audit team's ratings following
the presentation of the option ratings resulted in relatively casual,
uninvolved behavior by the host facility staff.
The pre-audit activities, particularly the pre-audit site visits,
were found to be extremely important in facilitating the audit process.
When the audit team spent a little more time getting to know the host
facility staff and the functioning of the organization, the audit process
moved more smoothly. The audit teair- found it easier and faster to
acquire needed data, because the members knew the operation and the
people a little better, and the level of cooperation by plant staff was
improved.
In summary, a WMA (and a WM program as a whole) requires that audit
team members exhibit effective communications and human interaction
skills, as well as technical insight and engineering ability. A
successful WM audit program thus requires success in both technical and
human relations areas.
3-16
-------
SECTION 4
LISTED WASTE F006 - WMA CASE STUDY
The focus of this case study is to propose ways to reduce or
eliminate the generation of listed waste F006. Generalized information
on the source and composition of this waste is available in the RCRA
listing background document (USEPA 1980). This waste is defined in 40
CFR 261.32 as follows:
F006: Wastewater treatment sludges from electroplating operations.
These sludges include cadmium and chromium hydroxides
precipitated in the central wastewater treatment facility at
the site.
A DOD installation that includes an electroplating facility
generating plating waste, was chosen as the host site.
FACILITY DESCRIPTION
The DOD installation, located in Eastern Alabama, is a major military
equipment servicing unit involved, among other activities, in the
rehabilitation of Army tanks and repair of small arms. The waste
minimization audit activities presented in this study are directed toward
these areas of the installation's activities.
With respect to tank overhaul and maintenance at the DOD
installation, the Army's M48s, M60s, M551s, and the new Ml Abrams tanks
are completely disassembled in the appropriate shops. Reusable parts and
those items that can be reclaimed are sent to satellite shops throughout
the area where they are stripped of rust, oil, and paint. As required,
various parts are plated, remachined, and surface coatings applied to
meet applicable specifications. The parts are then returned to the
assembly lines where they are used in rebuilding the tank hulls and
turrets. Assembled tanks are then tested and shipped.
With respect to small arms repair, weapons that have been classified
as "unserviceable" are sent to the DOD installation where they are
repaired. Like the tanks, the small arms are dismantled and faulty
components are replaced or repaired. The weapons parts are then
metal-finished, reassembled, and function test-fired to ensure they meet
quality standards prior to shipment.
4-1
-------
Cadmium/cyanide and chromium-bearing wastes are generated in plating
operations at the installation's plating shop (Building 114).1 At the
time of the WMA at Building 114, approximately 2,000 gallons per day of
cyanide-bearing waste were being generated and sent to the wastewater
treatment facility for treatment. This represents a considerable decline
in waste output (normal output is in the 7,000 to 10,000 gallons per day
range depending on plating shop production rate). About 35,000 gallons
per day of chromium-bearing wastewaters are sent to the wastewater
treatment facility. Normally, cadmium/cyanide or chromium plating baths
are discharged.
The combined wastewater treatment sludge (including the F006 waste
generated from treatment of cadmium/cyanide and chromium plating
wastewaters) from the industrial waste treatment facility (IWTF) averages
about 40,000 Ib/wk and is sent offsite to a hazardous waste landfill.
EQUIPMENT LAYOUT DESCRIPTION
All electroplating operations at the DOD installation are carried out
in Building 114. These include cadmium/cyanide plating, chromium
plating, and all related operations (phosphatizing, stripping, bright
dipping, degreasing, rinsing, anodizing, etc.). The dimensions and
operating specifications of the major equipment in the cadmium/cyanide
plating lines (including an automatic plating line using barrels to carry
the parts and a manually-operated rack line) are listed in Tables 8 and
9, respectively. Similar information for the manually operated chromium
plating line is shown in Tables 10 and 11, respectively.
All cadmium and chromium plating solutions are continuous filtered in
below-grade (basement level) filtration units. In order to enhance the
effectiveness of the hot rinsing operations, these rinse tanks are
equipped with air sparging devices. Agitation in plating and stripping
tanks is done either through pumparound circulation or air sparging.
During operations, overflow from the cadmium plating rinse tanks is
routed to a cadmium/cyanide sump, and then pumped to an alkaline
chlorination system for cyanide destruction (Building 506) prior to being
sent to the onsite Industrial Wastewater Treatment Plant (IWTP), as
described below. Overflow from the chromium plating rinse tanks is also
routed to the IWTP for treatment (as described below). Makeup water to
the rinse tanks is controlled by conductivity probes in these tanks.
A small amount of intermittent nickel plating is also carried out at
this facility.
4-2
-------
Table 8. Dimensions, Construction, and Capacity of Major Cadmium/Cyanide
Electroplating Line Equipment - Building 114
Vessel
No. Units Operation Size
Cadmium/cyanide manual rack^platinq line
1 1 HC1 pickling 4'x3'x6'
/
2 1 Running rinse 4'x3'x6'
3 1 Reverse current 4'x3'x6'
4 1 Cold rinse 4'x3'x6'
5 4 Cadmium plating 4'x3'x6'
5 4 Cadmium plating 16'x3'x6'
6 1 Still rinse tank 4'x3'x6'
7 1 Cold rinse 4'x3'x6'
8 1 Hot rinse 4'x3'x6'
9 2 Dichromate 4'x3'x6'
oxidizing bath
10 1 Still rinse 4'x3'x6'
11 1 Hot rinse 4'x3'x6'
Operating
capacity Vessel
(gallons) construction
450 Mild steel,
plastic-lined
495 Mild steel,
un lined
450 Mild steel,
un lined
495 Mild steel,
un lined
450 Mild steel,
un lined
1,800 Mild steel,
un lined
450 Mild steel,
un lined
495 Mild steel,
un lined
495 Mild steel,
un lined
450 Stainless
steel,
un lined
495 Mild steel,
un lined
495 Mild steel,
un lined
12
1 Drying oven
Front-loaded
adjustable shelf
Mild steel
4-3
-------
Table 8. (Continued)
Vessel
No.2 Units
Cadmium/cyanide
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
Operation Size
automatic barrel platinq line
Reverse current 32"x45"x28"
electrocleaning
Cold rinse 32"x45"x28"
HC1 pickling 32"x45"x28"
Cold rinse 32"x45"x28"
Blower for drying
workplaces
Cadmium plating
Still rinse 32"x45"x28"
Cold rinse 32"x45"x28"
Operating
capacity
(gallons)
150
150
150
150
-
1,100
150
150
Vessel
construction
Mild steel.
un 1 i ned
Hi Id steel,
un lined
Polypropylene
Polypropylene
-
Hi Id steel,
plastic lined
Hi Id steel,
un lined
Hi Id steel,
un lined
10
11
12
1 Oichromate 32"x45"x28"
oxidizing bath
1 Still rinse 32"x45"x28"
1 Hot rinse 32"x45"x28'
1 Blower for drying
workplaces
150
150
150
Polypropylene
Polypropylene
Stainless steel
Source: ODD installation in-house data.
Vessel numbers shown are arbitrary numbers used to identify the processing units and do
not correspond to the actual site numbering system.
4-4
-------
Table 9. Operating Specifications of Major Cadmium/Cyanide
Electroplating Line Equipment - Building 114
Vessel
No. Operation
Operating
temperature
'C CF) Chemicals used
Heating method Agitation method
Cadmium/cyanide manual rack plating line
1 HC1 pickling Ambient 13% HC1
2 Running rinse Ambient Running water rinse;
water addit ion
controlled by
conductivity
measurement
3 Reverse current Ambient Non-cyanide
alkaline cleaning
solution
4 Cold rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
Cadmium plating 21 (70) 18 oz/gal NaCN, Electric
2.5-3.5 oz/gal Cd immersion
metal, 6-8 oz/gal heaters
Na2C03
Cadmium plating 21 (70) 18 oz/gal NaCN, Electric
2/5-3.5 oz/gal Cd immersion
metal, 6-8 oz/gal heaters
Pumped circulation
with continuous
filtration
Pumped circulation
with continuous
filtration
Still rinse
tank
Ambient Ambient water rinse
Cold rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
8 Hot rinse
82 (180)
Hot water rinse;
water addition
controlled by
conductivity
measurement
Steam heated
coi Is
Air sparging
4-5
-------
Table 9. (Continued)
Vessel
No. Operation
Operating
temperature
C CF) Chemicals used
Heating method Agitation method
Cadmium/cyanide manual rack plating line
10
Dichromate
oxidizing bath
Still rinse
11
Hot rinse
93 (200) 0.03 oz/gal sodium
dichromate,
0.03 oz/gal
phosphor-a acid
Ambient Cold water rinse;
Mater addition
controlled by
conductivity
measurement
82 (180) Hot water rinse;
water addition
controlled by
conductivity
measurement
Steam heated
coils,
insulated
Steam heated
coils
Air sparging
12
Drying oven
93-260
(200-500)
Electric heat
Cadmium/cyanide automatic barrel plating line
1 Reverse current Ambient Non-cyanide
electroclean ing alkaline cleaning
solution
2 Cold rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
3 HC1 pickling Ambient 13% HC1
4 Cold rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
4-6
-------
Table 9. (Continued)
Vessel
No.2
Operation
Operating
temperature
C CF)
Chemicals used
Heating method Agitation method
Cadmium/cyanide automatic barrel plating line
Blower for dry-
ing workpieces
93-160
(200-500)
Cadmium plating 21 (70)
18 oz/gal NaCN,
2.5-3.5 oz/gal Cd
metal, 6-8 oz/gal
Electric
immersion
heaters
Pumped circulation
with continuous
fiItration
6 Still rinse Ambient Cold water rinse
7 Cold rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
Dichromate 93 (200) 0.03 oz/gal sodium Steam heated
oxidizing bath dichromate, coils,
0.03 oz/gal insulated
phosphoric acid
Air sparging
Still rinse Ambient Cold water rinse;
water addition
controlled by
conductivity
measurement
10
Hot rinse
82 (180)
Hot water rinse;
water addition
controlled by
conduct ivity
measurement
Steam heated
coils
Air sparging
11
Blower for dry-
ing workpieces
Source: DOD installation in-house data.
Vessel numbers shown are arbitrary numbers used to identify the processing units and do not
correspond to the actual site numbering system.
4-7
-------
Table 10. Dimensions, Construction, and Capacity of the Major Chromium
Electroplating Line Equipment - Building 114
Vessel
No.2 Units
Chromium olatina
1 1
2 1
3 1
4 1
5 2
6 6
7 6
8 1
Operation Size
line (manual or rack line]
Chromium strip- 6'x4'x8'
ping bath (if
required for old
chromium plate)
Preheat wax tank 6'x4'x3'
(preparation for
coating of part
areas not to be
chrome plated)
Wax dipping to 6'x3'x3'
cover part areas
not be to be
chrome plated
Chromic acid etch 3'x3'x3'
Chromium plating 8'x2.5'x8'
Chromium plating 16'x2.5'x6'
Cold water rinse 4'x4'x6'
De-wax cabinet
(for removal of
coating from
parts previously
coated in areas
not chrome plated)
Operating
capacity
(gallons)
1,260
(operating level
about 7 feet)
340
(operating level
about 2.5 feet)
140
(operating level
about 2 feet)
1,050
(operating level
about 7 feet)
1.500
(operating level
about 5 feet)
160
Sufficient
capacity to
remove wax
from 600 Ib
of parts per
hour
Vessel
construction
Mild steel,
lead- lined
Mild steel,
un lined
Mild steel,
un lined
Mild steel,
lead- lined
Mild steel,
lead- lined
Mild steel,
lead- lined
Mild steel
Mild steel
Source: DOD installation in-house data.
Vessel numbers shown are arbitrary numbers used to identify the processing units and do
not correspond to the actual site numbering system.
4-8
-------
Table 11. Operating Specifications of Major Chromium
Electroplating Line Equipment - Building 114
Vessel
2
No. Operation
Operating
temperature
C CF) Chemicals used
Heating method Agitation method
Chromium plating line (manual or rack line)
Chromium strip- 60 (140)
ping bath (if
required for old
chromium plate)
Sulfuric and chromic
acids, 10 oz/gal each
Steam heated
with titanium
coils
PVC sparger for
air agitation
Preheat wax tank (120)
(preparation for
coating of part
areas not to be
chrome plated)
Steam heated
Wax dipping to
cover part areas
not to be chrome
plated
49 (180) Petroleum wax
Steam heated
Chromic acid Ambient
etch
Chromium plating 60 (140)
Chromium plating 60 (140)
Chromic acid
(33 oz/gal),
sulfuric acid
(0.03 oz/gal)
Chromic acid
(33 oz/gal),
sulfuric acid
(0.33 oz/gal)
Chromic acid
(33 oz/gal),
sulfuric acid
(0.33 oz/gal)
Steam heated
with titanium
coils
Steam heated
with titanium
coils
PVC sparger for
air agitation
PVC sparger for
air agitation
4-9
-------
Table 11. (Continued)
Operating Specifications of Major Chromium
Electroplating Line Equipment - Building 114
Vessel
No.2
Operation
Operating
temperature
C CF)
Chemicals used
Heating method Agitation method
Chromium plating line (manual or rack lina)
Cold water rinse Ambient
Cold water rinse,
water addition
controlled by
conductivity
measurement
De-wax cabinet
(for removal of
coating from
parts previously
coated in areas
not chrome plated)
Heated to
melt wax
off parts
Steam heated
Source: DOD installation in-house data.
Vessel numbers shown are arbitrary numbers used to identify the processing units and do not
correspond to the actual site numbering system.
4-10
-------
PROCESS DESCRIPTION
Cadmium/Cyanide Plating
The only source of cadmium/cyanide waste at Building 114 comes from
rinse waters from selected cleaning operations and the dragout from
cadmium plating operations. Two cadmium plating operations are in use:
an automatic cadmium-cyanide plating line using barrels to hold the work
pieces, and a manually operated cadmium-cyanide plating line using racks
to hold the workpieces. Barrels are used for plating smaller parts, such
as nuts and bolts, that do not lend themselves to being rack mounted.
The automatic line is the most heavily used of the cadmium plating
lines. This line was being used on a continuous basis for one shift a
day at the time of the audit. The line has been used up to three shifts
per day in the past. Barrel-plating can generate significant amounts of
cyanide waste because of the high level of dragout often associated with
barrel-plating.
Figure 3 represents a simplified schematic of the automatic
cadmium-cyanide plating operation at Building 114. Based on discussions
with plant personnel, details of the automatic cadmium plating operations
are as follows:
Load: Parts are loaded into a barrel attached to a trolly hoist
that runs on a track above the process tanks. The loaded barrels
then proceed through the various steps using automatic sequencing.
Electroclean: The loaded barrels are dipped into a cleaning
solution and placed on reverse current. By passing an electric
current through the parts, gasing occurs on the metal surfaces,
which enhances the removal of dirt and oil.
Rinse: A tank containing tap water serves as an overflow rinse
tank to remove dragout. The water use in the rinse tank is
regulated by a conductivity controller.
Pickle: Parts are immersed in a hydrochloric acid (HC1) bath to
further remove oil, dirt, and oxide from the metal surfaces.
Rinse: A tank containing tap water serves to remove residual
HC1 from the pickled parts. Water use in this tank is regulated
by a conductivity controller.
Dry: The pickled and rinsed parts are blown dry before
immersion in the cadmium electroplating tank.
4-11
-------
ro
Legend
Worfcplece Flow
Waste Flow
Finished
Cadmium
Plated
Parts
Wastewater
to Acid/Base Sump
Waslewater
to Acid/Base Sump
r
Electro
Clean
1
Cold
Rinse
HCI
Pickle
t
Cold
Rlns*
Blow
Dryer
Cadmium
Plate
Hot
Air
Dryer
Hot
Rinse
Cold
Rinse
Chromate
Dip
Running
Rinse
Still
Rinse
Intermittent
Disposal
Wastewater
to Cr Sump
Wastewater
to Cd/CN Sump
Figure 3. Simplified Schematic: Automatic Barrel Cadmium Plating Line
-------
Electroplate: The cleaned parts are then immersed into a
plating tank containing a cadmium-cyanide electroplating
solution. Following the completion of the preset immersion time,
the barrel is slowly raised above the tank where air is blown
across the basket to reduce the amount of dragout.
Still Rinse: A tank containing tap water serves as the first
rinse tank to remove dragout after plating. No water runs into or
out of the tank during daily operation. At the end of the shift,
water from this tank is used to replenish water loss from the
plating solution caused by evaporation. The remaining water in
the tank is discharged to the cyanide sump.
Rinse: A tank containing tap water serves as a second rinse
tank following plating. Water use in the rinse tank is regulated
by a conductivity controller.
Chromating: The plated parts after rinsing are immersed in a
solution containing dichromates to form a corrosion protective
coating on the plated surfaces. No electric current is needed.
Rinse: A tank containing tap water serves as a rinse tank to
remove dragout after chromating. The barrel remains in the water
for approximately 4.5 minutes and is allowed to hang above the
rinse tank for 30 seconds before moving to the next tank. Water
use is regulated by a conductivity controller.
Hot Rinse: A tank containing heated tap water serves as the
final rinse for the parts. The tank is agitated with air sparging
for efficient rinsing. Hot water is used to allow for quick
drying of the parts to prevent streaking.
Dryer: The plated parts pass through a dryer which blows hot
air across the barrel to quickly dry the parts.
Unload: The plated and chromated parts are removed from the
barrel.
Four separate barrels are used along the automatic line at the same
time. It takes approximately 90 minutes for one barrel to complete the
plating circuit.
Wastes discharged from the automatic barrel line include the
following:
Residual still rinse tank water after the cadmium plating tank
is filled. This water discharges to the Cd/CN sump.
4-13
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Chromium-bearing rinse water from the chromating tank. This
waste discharges to the chrome sump as discussed below under the
chromium plating line process description.
Cold water rinse discharges from the electroclean and HC1 pickle
rinse tanks, respectively.
The manually operated rack line is used for parts that cannot be
barrel-plated because of their size or configuration. Figure 4
represents a simplified schematic of the manually operated
cadmium-cyanide plating operation. After placing the parts to be plated
on racks, the following procedure is followed:
Pickle: Parts are immersed in an HC1 bath to remove oil, dirt,
and oxide from the metal surfaces.
Rinse: There is a cold water rinse using tap water. Water use
in this tank is regulated by a conductivity controller.
Electroclean: The same process is used as in the automatic
barrel line.
Rinse: Another cold water rinse using tap water is undertaken.
Electroplate: The cleaned parts are then immersed in one of six
different plating tanks containing a cadmium-cyanide
electroplating solution. One of the plating tanks is located
adjacent to the rinse tank following electrocleaning. The other
five tanks are lined up adjacent to each other in a parallel line
with a walkway between the two lines. The parts may remain in a
plating tank anywhere from 5 minutes to an hour depending on the
amount of current the operator applies and the thickness of
plating required.
Still Rinse: The first rinse tank following plating is adjacent
to the single cadmium-cyanide plating tank. No tap water runs
into or out of the tank during daily operation.
Running Rinse: A tank containing tap water serves as a second
rinse tank to further remove dragout. Water use in the rinse tank
is regulated by a conductivity controller.
Chromating: The same process is used as in the automatic barrel
line.
4-14
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Flnll
Cadn
Plan
Parti
Legend
Workplace Flow
Waale Flow
Drying
Oven
bed
ilum
id
i
f
IHot
Rlnae
1
4
1 Cold ^ Chromate ^ Hot ^ Running ^ Still
Rlnae ~ Dip ^ Rlnae ^ Rlnae ~ Rlnae
1 1 1
1 1
Weilewator to Westewaler to
Cr Sump Cd/CN Sump at
End ol ShIN
Waatawalar to
Acld/Baaa Sump
Figure 4. Simplified Schematic: Manual Cadmium Plating Line
-------
Rinse: A tank containing tap water serves as a rinse tank to
remove dragout after chromating. Water use is regulated by a
conductivity controller.
Hot Rinse: A tank containing heated tap water serves as the
final rinse for the parts. The tank is agitated using an air
sparger for efficient rinsing. Hot water is used to allow for
quick drying of the parts to prevent streaking. An air hose helps
to dry the parts after the hot water rinse.
Drying Oven: The plated parts are transferred to an oven to be
air dried, completing the plating operation sequence.
Wastes discharged from the manual rack plating line are quite similar
to those discharged from the automatic barrel plating line with the
waste-waters containing cadmium and cyanide going to the Cd/CN sump in '
Building 114 and the chromium-bearing wastewaters going to the chromium
sump in Building 114.
For both the automatic barrel plating line and the manual rack line,
concentrations of the principal chemical constituents of the plating
baths are checked periodically and makeup materials are added as
required. The cadmium-cyanide plating baths are normally analyzed
weekly. The reverse current electroclear.er and HC1 pickling tanks are
checked monthly and the pickling baths are replaced three to four times
per year. The constituent compositions of the principal baths are
included in Table 8.
For both lines, plating solution tanks are completely cleaned once a
year. The plating solution is pumped to a holding tank and the plating
tank is thoroughly cleaned. Because of dragout of contaminant-laden
solutions and the continuous filtering of the plating and chromating
baths, replacement of these bath solutions is not required.
Hard Chrome Plating
Hard chrome plating at Building 114, while an important operation,
has a significantly lower plating volume than are cadmium plating.1
Chrome plating at Building 114 is a manual operation, often requiring
masking of various areas of the parts being plated. Figure 5 represents
a simplified schematic of the chromium plating operation. Based on
discussions with plant personnel, details of the chromium plating
operation follow:
Cadmium plating volume is approximately 100 times the chromium
plating volume.
4-16
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Legend
Workplace Flow
Watta Flow
Dryer
I
I"
-J
De-Wax
«-
Cold
Rlnaa
4-
Chroma
Plating
Waatewater to
Cr Sump
Finished
Chromium
Plated
Parts
Figure 5. Simplified Schematic: Manual Chromium Plating Line
-------
Chrome Stripping: When the old metal plate layer must be
removed, the parts are dipped into a tank containing a mixed acid
stripping solution, with the tank operating as a reverse current
stripper. The length of immersion time depends on the thickness
of the metal layer to be stripped.
Masking: Many parts that require hard chrome plating only need
a particular section of the piece to be plated. In most cases,
the chrome plate is needed to provide a specified hardness and
thickness to an engineered piece. To prevent the entire piece
from being plated, the area to be plated is covered with a special
tape and the piece is submerged in a hot wax. After the wax
cools, the tape is removed and the plating process continues. The
following tanks are used during the masking operation:
- Pre-heat wax: The piece is immersed in a heated bath to
preheat the surface before applying the wax. Pre-heating
results in a better adherence of wax.
- Wax dip: The piece is submerged in a tank of hot wax to mask
the areas not to be plated.
Pumice Rinse: The area to be plated is scrubbed with a mixture
of pumice, a gritty material, and water to help clean and roughen
the surface for better adhesion of the plated layer.
Pickling: The piece is immersed in a chromic acid bath to etch
and clean the surface, thus improving adhesion of the plated
layer. Chrome-plated parts, found to lack the required thickness
of metal, are reimmersed in the chromic acid bath before being
placed back into the chrome plating solution.
Chrome Plating: The cleaned and etched part is immersed into a
plating tank containing a chromic acid solution. The operator has
eight chrome plating tanks from which to choose. The length of
plating time depends on the amount of current applied and the
desired thickness.
Rinse: A tank containing tap water serves as a rinse tank to
remove the dragout after plating. Water use in the rinse tank is
regulated with a conductivity controller.
De-wax: A heated bath melts the wax off the parts upon
completion of the plating process.
4-18
-------
Wastewater discharges from the chromium plating line, including cold
water and hot water rinse tank overflows, are sent to the chromium
collection sump in Building 114. In addition, chromating tank rinse
water wastes from both the automatic barrel cadmium plating line and the
manual rack cadmium plating line contain appreciable chromate dragout,
requiring these discharges to be sent to the chromium waste sump in
Building 114. All chromium waste discharges are sent to the IWTP for
hexavalent chromium reduction and trivalent chromium precipitation.
Concentrations of the principal plating bath components are checked
periodically and makeup materials are added as required. The chromating
baths are normally analyzed weekly, while the chrome plating baths are
checked on a monthly basis. The constituent compositions of the
principal baths are found in Table 10.
Plating solution tanks are completely cleaned once a year. The
plating solution is pumped to a holding tank and the plating tank is
thoroughly cleaned. Because of dragout of contaminants-laden solution
and the continuous filtering of the plating and chromating baths,
replacement of these bath solutions is not required.
WASTE STREAM DESCRIPTION
The only appreciable cadmium/cyanide wastewaters at the DOD
installation are the rinse waters used to remove the dragout of plating
solutions from electroplating operations and certain parts cleaning
operations in Building 114. The major source of chromium wastewater is
the rinse waters used to remove the plating solution dragout on plated
metal parts in Building 114. Treatment of these wastewaters is described
below.
Current data on Building 114 wastewaters and the contaminants of
concern (Cd, CN, and Cr) are as follows:1
Waste Avg. wastewater flow Avq. contaminant concentration (mq/1)
stream (gallons per day) Cd CN Cr
Cd/CN sump 2,000 21 25
Cr sump 34,500 -- -- 116
Source: Letter from U.S. Army Environmental Hygiene Agency to
M. Drabkin, April 30, 1987, "Preliminary Data for the Anniston Army
Depot."
4-19
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CURRENT WASTE MANAGEMENT PROFILE
At the DOD installation, the hazardous wastes described above are
treated at the IWTP. The IWTP complex was extensively modified and
rebuilt in 1979. This system is designed to treat five separate wastes
generated at the DOD installation. These wastes include:
(A) Cadmium/cyanide wastewaters;
(B) Chromium wastewaters;
(C) Phenol- and other organics-bearing wastewaters;
(D) Steam cleaning wastewaters; and
(E) Miscellaneous metal finishing wastewaters.
Treatment of these wastes at the IWTP results in the generation and
disposal (in a hazardous waste landfill) of approximately 1,000 tons per
year of F006 waste. A schematic of the treatment process in use at the
IWTP is shown in Figure 6.
The two wastes of concern in the present WMA, streams (A) and (B),
are treated as follows:
(A) Cadmium/cyanide wastewaters. The only known sources of Cd/CN
wastewater at the DOD installation originate from plating operations
performed in Building 114. Dragout rinses from the plating operations
are routed to a sump in the basement of this building from where this
waste is pumped to one of four cyanide reactor/holding tanks in Building
506. Cyanide destruction via alkaline chlorination is performed in these
holding tanks on a batch basis, with subsequent transfer, chemical
coagulation, and precipitation of cadmium as cadmium hydroxide at the
IWTP.
The sequence of treatment steps includes the following:
1. Sump pumping from the basement of Building 114 to reactor
holding tanks in Building 506.
2. Cyanide destruction at Building 506 using HTH (CaHOCl), on a
batch basis, in one of four (2,400-gallon) reactor tanks.1
3. Transfer pumping to the IWTP.
4. Waste equalization in a completely mixed 10,000-gallon basin.
It is currently planned to change the treatment reagent from HTH to
liquified chlorine (a system for using the latter reagent is
available at the site). Use of chlorine rather than CaHOCl is
expected to improve operating efficiency of the alkaline
chlorination unit.
4-20
-------
OVERFLOW TO f.t.T.
WASTE SLUDOE TOC.S.T.
CNHOMI WASTE
PHENOL WACTE
NEACTOni AT ILDO IO«
LU»M HOLDNA TAMI
LUDOE CAKE
TO lECUME
LANOflLL
FH.TE*
CHEMICAL
STOMAOE
AND CONIMOL
UllOINO
STEAM CLIANMQ WAITtl
Of M(HAL WASTE
Figure 6. IWTP FLOW SCHEMATIC
Source: Halcoln Pirnie, 1986. Initial Report.
Industrial Wastewater Minimization Program
-------
5. Transfer pumping to flocculation vessels.
6. Lime addition to effect cadmium precipitation as the hydroxide
at a pH of 11 (in one of two Cd clarifiers).
7. Polymer addition and flocculation in two parallel BSD-gallon
fiberglass tanks.
8. Clarification (first clarifier) within a basin having a capacity
of approximately 14,000 gallons and a surface area of 210 ft2.
i
9. Flow equalization and pressure filtration.1
10. Sulfide addition for additional cadmium precipitation as the
sulfide (in the other of the two Cd clarifiers).1
11. Clarification (second clarifier) within a basin having a
capacity of approximately 14,000 gallons and a surface area of
210 ft2.1
12. Effluent discharged to influent of General Metal Finishing
treatment system. This treated waste is ultimately discharged
through the DOD installation sanitary treatment system discharge
point under a State of Alabama NPDES permit.
13. Collection of the clarifier underflows in a sludge holding tank,
followed by dewatering in a plate and frame filter press and
discharged to a hazardous waste landfill.
(B) Chromium wastewaters. Chromium wastewater at the DOD
installation primarily originates from plating operations in Building
114. Dragout rinses from selected stripping and plating operations are
sent to the IWTP for treatment in a series of steps as described below.
1. Sump pumping from the basement of Building 114.
2. Transfer pumping from Building 506 to the IWTP.
1 This is a recent modification in operating procedures.
4-22
-------
3. Influent pumping to one of three reactor tanks (12,500 gallons
each) for batch Cr"1"6 reduction to Cr+3 followed by lime (or
NaOH) and polymer addition for hydroxide precipitation. Batch
chromium treatment at the IWTP involves reduction of the
hexavalent (+6) ion to the trivalent (+3) form. The first step
for Cr+° reduction is to lower the pH 2.5 to 3.0 with sulfuric
acid followed by the addition of sodium metabisulfite (reducing
agent). Operators are utilizing the color change from yellow to
green as an indication that the hexavalent ion has been
reduced. Once the hexavalent chromium has been reduced to the
trivalent state, lime (or caustic) is added to raise the pH from
8.0 to 9.0, which precipitates chromium (+3) hydroxide from
solution.
4. Clarification of the treated wastewater within two parallel
clarifiers, each having a capacity of approximately 14,000
gallons and a surface area of 210 ft . The chromium hydroxide
settles in the two clarifiers with the aid of polymer addition.
5. Effluent discharge to influent of General Metal Finishing
treatment system and ultimate discharge through the sanitary
treatment system discharge point.under a State of Alabama NPDES
permit.
6. Collection of the clarifier underflows in a sludge holding tank,
followed by dewatering of the sludge in a plate and frame filter
press and discharge to a hazardous waste landfill.
POSTULATED WASTE MINIMIZATION OPTIONS
Waste minimization options for reducing or eliminating the generation
of listed hazardous waste F006 from electroplating operations in Building
114 were developed by the audit team using the approved EPA hierarchy:
source reduction options being more desirable and recycle/reuse options
less desirable. Treatment options (not considered as waste minimization)
were only explored if no source reduction or recycle/reuse options were
available for these wastes. The options considered under these
categories are discussed below.
Cadmium/Cyanide Wastes Generated in Building 114
Compliance with the current NPDES permit limit requirements for total
cyanide and, to a lesser extent, cadmium, remains the most serious
problem in meeting State permit requirements at the DOD installation.
The present total cyanide limit is 0.5 mg/1 (daily average). During the
period from mid-August to mid-November 1986, the IWTP was out of
4-23
-------
compliance for total cyanide in more than 50 percent of the daily average
values recorded during this period. Of the noncompliance values
determined for total cyanide, most appeared to be primarily levels of
nonamenable cyanide, i.e., complex cyanides not susceptible to
destruction by the alkaline chlorination process in use at the IWTP. In
the case of the cadmium compliance level (the NPDES daily average value
being 0.1 mg/1) over the same period, the IWTP performance was far
better, with only 2 out of 32 measured values of treated effluent cadmium
found to be out of compliance. Thus, waste minimization efforts were
directed principally at cyanide waste generation (and, to a lesser
extent, cadmium waste generation) in order to alleviate the problem of
compliance with the IWTF discharge.
(1) Source reduction options. The following source reduction
options were considered for reduction and/or elimination of Cd/CN wastes.
Option (a). Minimizing rinse water usage. Both the automatic barrel
line and manually operated rack lines employ a cold water rinse
immediately following the alkaline electroclean (reverse current
cleaning) and HC1 pickling of the workpieces. This rinse is done in
single tanks, each fed separately with tap water as required. Referring
to Figure 1, if the cold rinse.water discharge following alkaline reverse
current cleaning on the automatic barrel line is piped to the HC1
pickling rinse tank, a reduction in rinse water flow would be achieved,
neutralization of the acidic rinse water would occur, and wastewater flow
to the IWTP would be reduced. There would be a relatively inexpensive
piping and pumping cost involved in implementing this option. The same
approach can be taken with the Cd/CN rack line (Figure 2), with the cold
water rinse following reverse current cleaning being pumped to the cold
water rinse tank following the HC1 pickling operation. This option does
not directly affect cadmium/cyanide waste reduction, but should
significantly reduce the amount of waste requiring treatment at the IWTF.
Option (b). Destruction of cyanides by reverse current treatment.
The electrolytic destruction of both simple and complex cyanides can
occur at the anode of an electrolytic cell using reverse current
electrolysis. At a high enough current density and sufficient residence
time, cyanides will be oxidized to nitrogen and CO? at the anode. It
is proposed to use this reaction as a means of destroying waste cyanide
in the still rinse tanks immediately following the Cd/CN plating tanks,
as well as in the electroclean rinse tank in each of the cadmium plating
systems in Building 114 (see Figures 1 and 2). These systems are out of
operation during 16 hours each day (plating operations are carried out on
the 8:00 to 4:00 shift). During this 16-hour period following shutdown
of the cadmium plating lines, the following sequence of steps would occur
(as applied to the still rinse tank in the automatic barrel line):
4-24
-------
1. Water from the still rinse tank would be used to raise the
cadmium plating bath to its desired level.
2. The still rinse tank is then filled with water from the adjacent
running rinse tank. The still rinse tank water is kept
thoroughly mixed through the use of an air sparger (preferred
over a mechanical agitator because of faster circulation of fluid
through the tank).
3. Passivated 316 stainless steel cathode plates and 316 stainless
steel anode plates are placed along opposite walls of the still
rinse tank. An anode to cathode surface area ratio of 1 to 1 is
used and the maximum available electrode surface area is employed.
4. Cyanide is destroyed in the still tank by using 8 to 20 amps per
square feet of anode. A residence time of up to 16 hours is
available for cyanide destruction. A current density as high as
possible is used with care taken not to overheat rectifier
contacts. If overheating occurs, the amperage is reduced.
5. At the end of 16 hours the rectifier is turned off and the anode
and cathode plates are removed. Some cadmium may plate out on
the cathodes. The recovered cadmium is stripped from these
plates and used during the regular plating operations.
An analogous procedure can be used for the cadmium rack plating line,
destroying the cyanide in the still rinse tank in use in that line.
The only additional equipment unavailable to carry out this option is
appropriate sets of 316 stainless steel anode and cathode plates. All
other equipment, including suitable rectifiers to supply the high current
density needed for cyanide destruction is currently on hand at the DOD
installation.
The technical feasibility of this option will be ascertained through
an experiment to be carried out in the still rinse tank on the automatic
barrel line. If this technique proves successful, it is believed that
the bulk of the cyanide present in the wastewater discharged to the Cd/CN
sump in the sump in Building 114, would be destroyed (including the
nonamenable complexed cyanides), with the existing alkaline chlorination
system in the IWTP acting as a backup or polishing step to assure that
the total cyanide compliance level is achieved.
Option (c). Improve dragout recovery. A drain board positioned
between the cadmium plating bath on the manual rack plating line and the
adjacent still rinse bath can capture the solution dripping off of a
workpiece and channel it back to the plating bath. This is a simple but
effective operation and can be incorporated into the present
4-25
-------
electroplating process. The drain board can be made of plastic,
corrosion-resistant metal, or any other nonreactive materials. The board
should be placed slightly sloped toward the plating tank so that drained
solution can be routed back to the bath. Once fastened to the tanks, the
drain board can serve as a workpiece rest area to allow for adequate
drainage in 10 to 30 seconds. The drain board should be cleaned
periodically to prevent the accumulation of dirt and the resulting
drag-in of contaminants into the cadmium plating bath.
Spray or fog rinsing applied directly over the heated cadmium plating
tanks in the manual rack plating line can also substantially reduce the
solution dragout rate as well as reduce water consumption. The spray or
fog nozzle uses water and air pressure to produce a fine mist. Spraying
water droplets directly onto a workpiece is much more efficient than
immersing a workpiece into a liquid water bath. A major limitation is
that spraying is not effective on oddly shaped parts, since the spray
cannot make contact with the entire surface of the object. Sufficiently
high surface evaporation rates must exist for those plating tanks using
the technique.
(2) Recycle/reuse options. One recycle/reuse option appeared to be
available for the Cd/CN wastes generated by the plating operations in
Building 114, as described below:
Option (d). Evaporation of Cd/CN plating system wastewater. Plating
system wastewaters from both the Cd/CN automatic barrel line and rack
line currently total about 2,000 gallons per day at a CN concentration of
25 mg/1. If Option (b) proves unsuccessful in destroying CN in the
plating line still rinse tanks, another commercially available option
would be evaporation of this wastewater stream in suitable equipment, and
returning the concentrated CN solution to the respective Cd plating tanks
in the two plating lines. Sufficient evaporation of this waste stream
would be required to maintain a water balance in the plating lines, i.e.,
replacement of the daily water losses from the respective Cd plating
tanks. Appropriate amounts of sodium cyanide reagent and cadmium metal
would be added to the plating baths as needed to maintain concentration
levels in these baths. With installation of this option, the alkaline
chlorination unit presently being operated at the IWTP for CN destruction
can be shut down, and maintained on standby only, since there would be no
CN discharge from Building 114.
Typical systems and costs for evaporation of waste CN plating
solution are described in the plating industry trade literature
(Williamson and Natof, 1985) as well as in EPA documentation (USEPA 1985).
Implementation of this option is assumed to require evaporation of
90 percent of the generated Cd/CN wastewater in order to recirculate 200
gpd of the concentrated CN solution to the two plating lines (replacing
4-26
-------
200 gpd of water that is assumed to be required as dally makeup to the
two plating lines). The evaporation system would be located in the
basement level of Building 114 near the Cd/CN wastewater collection
sump. The evaporator is assumed to be of the vacuum type, with
evaporator body and tubes of borosilicate glass for highly corrosive
duty. The total installed cost of the evaporation unit (including vacuum
evaporator, product and water reuse-water feed tanks, condensate and
product return pumps, rinse water filter, all piping, electrical work,
and installation), is estimated as $79,000 for a feed rate of 75 gallons
per hour, 24 hours per day, 250 days per year. Direct operating costs of
this unit are estimated as $27,000 per year including steam, electricity,
direct labor, cooling water, and maintenance. The payback period for
this unit cannot be estimated since savings in Cd/CN wastewater treatment
costs resulting from shutdown of the alkaline chlorination unit, are not
available. However, the IWTP would be in compliance with respect to one
of its most significant current problems - meeting the NPDES CN discharge
limits.
Option (e). Recovery of cadmium from Cd/CN plating wastes. A
similar concept employed for cyanide destruction (reverse current
electrolysis as described in option (b)), can be employed to recover
cadmium from the still rinse tank immediately following the cadmium
plating tank in each of the Cd/CN plating lines in Building 114. In this
case, cadmium would plate out on the passivated cathode in the tanks at a
low current density (2 to 5 amps per square foot of cathode surface).
The concentration of cadmium in these tanks, while presently not known,
should be the highest of any of the rinse tanks employed in the plating
line, since this tank receives the dragout from the cadmium plating
tanks. A preliminary estimate of the dragout into this tank in the
automatic barrel line is 2.5 Ib of cadmium metal per 8-hour shift
(SAIC 1986). The recovered cadmium would be recycled to the cadmium
plating tanks by inserting the cadmium-coated plates into the plating
tanks during the 8 hours of plating operations.
Application of the reverse current electrolytic technique to the
still rinse tanks in the two Cd/CN electrolytic lines during the 16-hour
downtime period can reduce the cadmium level significantly in the
wastewater to the Cd/CN sump in Building 114. Since cyanide destruction
has the primary emphasis (option b), the reverse current operation would
operate for maximum cadmium plateout for only that portion of the 16-hour
period (at low current density) consistent with sufficient time allowed
for maximum cyanide destruction. The recovery of the relatively small
amount of cadmium metal for its value alone could not be justified
because of the cost of labor and power involved. However, the lower
overall cadmium level in the Cd/CN wastewater achievable by this method,
does reduce the treatment load at the IWTP significantly, thereby
lowering treatment costs and ensuring the achievement of the NPDES
cadmium compliance level in the effluent from the facility.
4-27
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Chromium Wastes
(1) Source reduction options. The following source reduction
options were considered for reduction and/or elimination of chromium
wastes.
Option (f). Improved dragout recovery. A drain board positioned
between each chromium plating bath and its adjacent rinse tank can
capture the solution dripping off of a workpiece and channel it back to
the plating bath. This is a simple but effective operation and can be
incorporated into the present electroplating process. The drain board
can be made of plastic, corrosion-resistant metal, or any other
nonreactive material. The board should be placed slightly sloped toward
the plating tank so that drained solution can be routed back to the
bath. Once fastened to the tanks, the drain board can serve as a
workpiece rest area to allow for adequate drainage in 10 to 30 seconds.
The drain board should be cleaned periodically to prevent the
accumulation of dirt and the resulting drag-in of contaminants into the
chromium plating baths.
Spray or fog rinsing applied directly over the heated chromium
plating tanks can also substantially reduce the solution dragout rate as
well as reduce water consumption. The spray or fog nozzle uses water and
air pressure to produce a fine mist. Spraying water droplets directly
onto a workpiece is much more efficient than immersing a workpiece into a
liquid water bath. A major limitation is that spraying is not effective
on oddly shaped parts, since the spray cannot make contact with the
entire surface of the object. Sufficient surface evaporation rates must
exist for those plating tanks that will use the technique.
Another method of spray rinsing using a spray chamber in place of a
running rinse tank could also be utilized along the chromium plating
line. The existing rinse tanks could be fitted with spray nozzle rings.
It will be necessary to install one spray nozzle ring for every foot of
the tank's depth to provide adequate rinsing of the workpiece. The
limitation on oddly-shaped objects still applies to this type of spray
rinsing system. Not only will this technique significantly reduce water
requirements but it may also be able to generate a more concentrated
chromium waste stream that is more susceptible to recycle/recovery
techniques than are rinse waters from a running rinse tank.
Option (g). Reduction of chromium loss in ventilation hoods. To
reduce the amount of chromium-bearing vapors being sucked up into the
ventilation hoods mounted over the heated chrome-pi ating tanks, the
addition of plastic balls to cover the surface of the hot chromate
plating solution is recommended. The balls would provide surface areas
on which to condense the entrained chrome-bearing mist leaving the hot
4-28
-------
plating solution. No data are available on the present chromium losses
resulting from entrainment through the hood vents. However, it is
believed that using this method could greatly reduce chromium loss, and
equipment and maintenance costs would be minimal.
(2) Recycle/reuse options
Option (h). Evaporation of chromium-bearing rinse waters. There is
increased interest in the use of evaporation for recovery of
chromium-bearing solutions from electroplating wastewaters, since the
equipment involved is relatively inexpensive to install and operate,
making it a useful tool for minimizing hazardous waste generation. Many
atmosphere evaporators are in use for recovery of dragout from hexavalent
chromium plating operations.
Application of evaporative recovery to the Cr sump wastewater from
Building 114 involves concentrating the chromium content from an average
of 116 mg/1 to approximately 250 gm/1 (about a 2,000 to 1 concentration
factor). For the daily average discharge rate of 34,500 gal/day, this
involves the evaporation of all but 17 gal/day of water - clearly an
uneconomical approach. In addition, the amount of potentially
recoverable chromium (as chromic acid) of 33 Ib/day at an approximate
recoverable value of $50/day, is not economically justifiable for the
capital and operating expense involved. This option could become of
greater interest if the rinse water volume generated from the Cr plating
line is materially reduced by techniques such as those discussed under
option (e).
PROJECTED COSTS FOR THE PROPOSED WM OPTIONS '
As additional input for evaluating the feasibility of the proposed WM
options for the F006 wastes discussed above, projected costs (order of
magnitude cost estimates) have been developed, and the results are
summarized in Table 12. Two estimates of the payback period may be
derived from the installation of the WM options presented in Table 12 and
consideration of the present cost of disposal of the hazardous F006
sludge generated by the IWTP:
- An estimate of payback if the proposed source reduction options
(a)(l) and (2), (b)(l) and (2), (c)(l) and (2), (f), and (g) and
recycle/reuse options (e)(l) and (2) are installed. In this
scenario, the total annual cost in 1986 of disposal of the F006
sludge in a hazardous waste landfill was approximately $160,000
($160/ton). Assuming that the F006 can be suitably delisted by
EPA, and the nonhazardous waste resulting from this delisting can
be disposed of in a local sanitary landfill at a cost of $40/ton,
then the annual savings in disposal costs would be $120,000.
4-29
-------
Table 12. Tabulated Projected Costs: WM Options for DOD Installation F006 Wastes1
WM
option
Option
Waste source type
Proposed equipment
Option description modifications
Estimated
installed
cost (S)1
Estimated annual
operating cost
($/yr)
(a)(l) Cd/CN Barrel Plating Source
Line reduction
Use of electroclean rinse
waters as feed to pickling
rinse water tank
Water piping and pump
$ 1.000
$ 500
(a)(2) Cd/CN Manual Plating Source
Line reduction
Use of electroclean rinse
waters as feed to pickling
rinse water tank
Water piping and pump
1.000
500
(b)(l) Cd/CN Barrel Plating Source
Line reduction
-C*
i
to
o
(b)(2) Cd/CN Manual Plating Source
Line reduction
Destruction of cyanides in
sti11 rinse tank
Destruction of cyanides in
sti11 rinse tank
Insertion of SS cathodes and 2,000
anodes in still rinse tank
and operation in a CN
destruction mode during
plating line downtime
Insertion of SS cathodes and 2.000
anodes in still rinse tank
and operation in a CN
destruction mode during
plating line downtime
10,000
10,000
(c)(l) Cd/CN Manual Plating Source
Line reduction
(c)(2) Chromium Manual Source
Plating Line reduction
Improved dragout recovery;
drain board, spray/fog
rinsing nozzles over
plating tank
Improved dragout recovery;
drain board, spray/fog
rinsing
Add drain board between Cd 1,500
plating tank and still rinse
tank; install spray/fog rinse
Add drain board between Cr 1,500
plating tank and still rinse
tank; install spray/fog rinse
nozzles over plating tank
1.000
1,000
-------
Table 12~" (Continued)
WM
option Waste source
(d) Both Cd/CN Plating
Lines
Option
type
Recycle/
reuse
Option description
Evaporation of Cd/CN rinse
water discharge and recycle
Estimated
Proposed equipment installed
modifications cost ($)
Install evaporation unit and 79,000
auxiliaries in Building 114
Estimated annual
operating cost
($/yr)
27.000
to both plating lines in
appropriate quantities to
maintain individual plating
bath water balances
basement near Cd/CN waste
sump
Cd/CN Barrel Plating
Line '
Recycle/reuse Plating out of cadmium in
still rinse tank
Insertion of SS cathodes and Use the same
anodes in still rinse tank equipment
to operate in a Cd plating as in (b)
mode during plating line
downtime
20.000
CO
Cd/CN Manual
Plating Line
Recycle/reuse
Plating out of cadmium in
still rinse tank
Insertion of SS cathodes and Use the same
anodes in still rinse tank equipment
to operate in a Cd plating as in (b)
mode during plating line
downtime
20,000
(f) Chromium Manual Source Improved dragout recovery:
Plating Line reduction replacement of running
rinse tank with spray chamber
(g) Chromium Manual Source Reduction of chromium metal
Plating line reduction losses from hood vents over
plating tanks
Install suitable banks of 5.000
spray nozzles in empty
running rinse tank
Add layer of plastic balls Nil
on surface of chromium
plating tanks
2.000
Nil
1
Order of magnitude costs (,+ 50 percent accuracy).
-------
After deducting the incremental operating costs associated with
the installed WM options listed above, the payback period would be
14,000/55,000 or approximately 4 months.
- An estimate of the payback if the proposed source reduction
options (a)(l) and (2), (c)(l) and (2), (f), and (g) and
recycle/reuse options (d) and (e)(l) and (2) are installed. In
this scenario, the net annual savings in waste disposal costs
would again be $120,000 (assuming that the F006 waste can be
suitably delisted). After deducting the incremental operating
costs associated with the installed WM options listed above, the
payback period would be 89,000/48,000 or 1.9 years.
None of the proposed source reduction or recycle/reuse options would
require any additional space requirements (except for option (c) for
which adequate space is believed to be available in the basement of
Building 114), or extensive modification of existing equipment.
SUMMARY AND DISCUSSION
The F006 waste generated from electroplating processes is a large
volume waste product. For the DOD installation, approximately 1,000 tons
per year of this waste are sent offsite for disposal in a hazardous waste
landfill. In addition to the required disposal of this waste in a
hazardous waste landfill, the installation is required to meet low levels
of Cd, Cr (total), and CN in effluents covered by an NPDES discharge
permit. Currently (and for some time in the past) the DOD installation
is having great difficulty in meeting the CN discharge limit. The
facility was also having difficulty in meeting the required Cd level in
the effluent, but since installation of WM option (e)(l) and (2) in
mid-summer of 1987 (see Table 12), this problem appears to have been
eliminated.
In summary, the results of the WMA conducted at Building 114 of the
DOD installation by the EPA-sponsored audit team, clearly indicated that
a number of source reduction and recycle/reuse options may be implemented
in Building 114, with a potential payback ranging from 4 months to
1.9 years depending on the choice of options. One recycle/reuse option
(recovery of cadmium metal from the still rinse tanks in each of the
Recent NPDES effluent data furnished by the DOD installation appear
to prove this point. Prior to the mid-summer installation of WM
option (e)(l) and (2), Cd levels during the March-June 1987 period
exceeded NPDES levels for over 50 percent of the daily Cd values
measured. During the July-September 1987 period, not one exceedance
of the permitted Cd levels occurred for the 40 days of measured Cd
levels.
4-32
-------
plating lines) has already been tested by the facility and found to be
feasible, and, as indicated above, has resulted in a significant
reduction in Cd levels in the NPDES effluent, assuring compliance with
the required effluent level. With respect to a reduction of the CN level
in Building 114 Cd/CN wastewater (affecting the CN level in the NPDES
discharge), one source reduction option may be available: reverse
current destruction of CN in the still rinse tank during the plating line
daily downtime period. This option is currently being evaluated at the
facility. A recycle/reuse option, concentration of Cd/CN plating rinse
water and return to the plating tanks, is commercially available and may
represent the solution to the NPDES CN compliance problem if the source
reduction option proves infeasible. A number of source reduction options
for reducing Cr levels in that plating line rinse water waste, are also
available to reduce Cr levels in the F006 sludge, as well as to reduce
the total amount of this sludge.
4-33
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SECTION 5
LISTED WASTES F002 and F004 - WMA CASE STUDY
The focus of this case study is to propose ways to reduce or
eliminate the generation of listed wastes F002 and F004. These wastes
are defined in 40 CFR 261.32 as follows:
F002: Spent halogenated solvents including methylene chloride; and
F004: Spent nonhalogenated solvents including cresols and cresylic
acids.
A DOD installation that includes a facility generating these solvent
wastes from paint stripping operations, was chosen as the host site.
FACILITY DESCRIPTION
(See Section 4)
EQUIPMENT LAYOUT DESCRIPTION
Solvent stripping operations for removal of epoxy paints (and to a
lesser extent) polyurethane paints from various tank parts rehabilitated
at the DOD installation, are carried out principally in Buildings 129,
130, and 409. Most of the large tank components are stripped by dry
abrasives, with the more intricate and delicate components being dipped
in stripping solvents. Wastewaters carrying solvent dragout from the
paint stripping operations are routed to the IWTP for treatment. Figures
7, 8, and 9 present schematics of the production area layouts and
wastewater discharge points in these buildings, respectively. Table 13
summarizes the tank capacity for organic solvents in use for paint
stripping operations in Buildings 129, 130, and 409.
5-1
-------
GENERAL WASTE A
CHROMIUM OVX*
'£ . \N
O-TR w
AREAS '
-*v
^
*^
y
\
\
*_/
.>
i
>
/- STEAM
/ CLEANING
/ STATION
, / \ /
^
03
,?=-=
-S
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SUMP
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f=
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a
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/-FORCE
/ MAIN
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-g:Ur
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u
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,
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f
r STEAM
CLEANING
STATION
\ /
r:~~~.i}
*=>
ij
§n ipi fc
8s 1
c
I
1
X. - / / STEAM
N. / STORM// GENERAL WASTE
/~r\ ^y^ D^ J/r CHB°ME 'f'
/ / \ ffJ^L ^
/ \ " /*
1TANK CONTENTS /^
A - Vapor Degreaser y^
B - Alkali Strip 4/
C - Hot H20 Rinse (To QW)
D - Alkali Strip
E - Empty
F - OH
Q - H3PO 4
H - Penaacola Strip
1 - Penaacola Strip
i - Hot H2O Rinse (To Phenol)
K - Alkali Corrosion Remover
L - Empty (Formaly Cold HgO Rinse)
M - Empty (Formaly H3PO4)
N - Oil
O - Chromic Acid
P - Cold H2O Rinse (To GW)
Q - Phosphatlzlng
^gure 7. PRODUCTION AREA LAYOUT AND WASTEWAIER DISCHARGE SCHEMA
1 i
TIC FOR BUILDING 129*
I
^Source: Malcolm Plrnle, 1986. Initial Report.
'Industrial H««:tPV«»r.pr M1rHml7«t.1on Prnoram
-------
CHROMIUM
PIPES ARE
CONTAINED
WITHIN FLOOR
TRENCH
CHROMIUM
STEAM
GENERAL WASTE
'NOTE: TANK *N' DRAINS
TO CHROME WASTE
TO TRENCH
PIPES ARE CONTAINED
WITHIN FLOOR TRENCH
FLOOR TRENCH
DRAINS TO
GENERAL WASTE
STEAM FORCE MAIN-/
FLOOR TRENCH
DRAINS TO
GENERAL WASTE
CHROMIUM
PAINT BOOTH
-FLOOR TRENCH
STEAM FORCE
A-VAPOR DEQREASER
B-HOT HO RINSE (TO QW)
D-ALKALI CORROSION REMOVER
E-HOT H2O RINSE (TO QW)
F-PENSOCOLA STRIP
Q-HOT H2O RINSE (TO PHENOL)
H-PENSOCOLA STRIP
I-ABERDEEN STRIP
J-HOT HO RINSE (TO QW)
K-HOT HO RINSE
L-ALKALl CORHOSION REMOVER
M-H PO
N-HOT H20 RINSE (TO CHROMIUM)
O-CHROMIC ACID
SUMP PUMP
Figure 8. PRODUCTION AREA LAYOUT AND WASTEV/ATER DISCHARGE SCHEMATIC FOR BUILDING 13O
'Source: Malcolm Plrnle, 1986. Initial Report.
Industrial Wastewater Minimizalton Program
-------
TANK CONTENTS
A - AlkcM Conation RvmovM
B - Hoi M2O nWiM ( I o OW)
C - Alkali Conoiton R*mov«f
O - Hoi H20 f«ni« (To QW)
6 - HjPO^
F - H3P04
Q-MCI
H - Hat H2O Wn«« (To OW)
I- ON
J- AlMrOMn Strip
K - Hoi HjO MnM(To Cr or Phenol)
in
i
tAMO (lONinC 4
FAIMI SIOMAOf DOOM
PAINT
OOIH
OH VINO OVEN
II*
TO IWI
lP 1
»-
u
-
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rA
o
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m
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IN
O
rT
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&
^
T
rH "
trie
AT
B
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1
1
<
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NO
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OL «
ri
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at
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r
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-
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III
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/""'', '/"""
/ / ""*
/ /
0 IT T" J K
\ n it
| /- OtNillAt. WACTI
171 Bf-i""'
J ^TO IWIP^-IO IWtP
PAINT
OOTN
-CNHOMI
WAITtLINI
OHVINa OVCN
Alll CLACT HOOM
CNBOMf WA«Tt
UMPA ruur
- - TO iwir
Figure 9. PRODUCTION AREA LAYOUT AND WASTEVV^TER DISCHARGE SCHEMATIC FOR BUILDING 409
Source: Malcoln Plrnle, 1986. JnlUal ReportL
Minimization Proqram
-------
Table 13. Paint Stripping Solvent Handling Capacity
at the DOD Installation
Building No.
129 West
130
409
Tank capacity Trade name of paint
Tank No. (gallons) solvent formulation
1
2
1
2
3
1
Total
1,200 Pensacola
1,100 Pensacola
2.150 B and B
1 , 558 Aberdeen
1,558 Aberdeen
3.000 Aberdeen
10.566
Source: DOD installation in-house data.
These numbers are arbitrary designations assigned to these units and
do not correspond to the actual site designations.
Formulation compositions discussed in Process Description portion of
Section 5.
This formulation is currently replaced with an experimental paint
solvent formulation intended to provide better stripping performance
on urethane painted tank parts.
5-5
-------
PROCESS DESCRIPTION
When refurbishing tank vehicles at the DOD installation, an extensive
amount of paint stripping must be performed on each vehicle. Paint
formulations for years have largely been comprised of epoxies and
enamels, although developmental work and successful testing of new
product coatings by the Army has recently required the DOD installation
to begin to use a new urethane coating system. This new urethane finish
is more resistant to conventional stripping formulations presently used
at this installation.
Discussions with plant personnel indicated that a significant
percentage of the parts associated with tank refurbishing are stripped
with dry abrasives, such as steel shot and other granulated materials.
However, there are some components whose use, geometry, or product
specifications require that they be stripped by other than dry abrasives,
such as by chemical strippers in a liquid bath. These chemical
formulations vary from alkali to acidic solutions, with bath temperatures
ranging from hot to ambient. The organic stripping solutions are all
used at ambient temperature. The majority of the chemical (paint)
stripping formulations are acidic in nature and contain various organic
chemical combinations depending upon the manufacturer selected. Table 14
summarizes the organic chemicals used and the ranges of concentration in
the various formulations employed for paint stripping.
Table 14. Chemical Constituents and Their Ranges of Concentrations
in the Paint Stripping Solvents Used at the DOD Installation
Range of percentages used in the
Chemical various stripping formulations
Methylene chloride 40 to 88%
Phenol 5 to 25%
Cresol 0 to 5%
Formic acid 5 to 15%
Methanol 5 to 20%
A summary of the different types of paint stripping solvents used in
each of the production areas, as well as the ingredients in each solvent,
is given in Table 15.
5-6
-------
Table 15. Ingredients and Usage Locations of Paint Stripping
Solvents Used at the DOD Installation
Building -
location
Paint solvent
trade name1*
Principal
ingredients
Comments
129 West
130
409
Pensacola Strip
(Type I)
B and B Strip
Aberdeen Strip
Aberdeen Strip
Methylene chloride
Cresol
Oleic acid
Phenol
Methylene chloride
Cresol
Methylene chloride
Cresol
Formic acid
Methylene Chloride
Cresol
Formic acid
Used on Al, Mg,
and steel parts
Used on Al and
steel parts
Al parts only
Al parts only
1 The percentage of each of these ingredients will vary, depending upon
the paint solvent formulator selected. In addition, the solvents may
also contain
any combination of the following: benzene, alcohols, EDTA, solvents,
naptha, and chromates.
Operation of the paint stripping solvent tanks consists of suspending
baskets of the painted tank parts to be stripped in the appropriate
solvent tank, followed by immersion in a hot water rinse in an adjacent
tank. Details of the solvent point stripping operations at the various
locations in the DOD installation are as follows:
- Building 129 West has two tanks that contain the phenolic-based
Pensacola stripping formulation. Paint stripping within this area
is normally performed on aluminum transmission cases as well as on
magnesium parts. Following the stripping operation, most of the
dragout is manually sprayed and hosed off from the workpiece
before it receives a hot rinse in an adjacent tank. The rinse
water from the manual spray rinsing step flows into a floor drain
and is directed to the steam cleaning system. The overflow from
the hot rinse tank was recently disconnected from the steam
cleaning system and routed to the phenol waste collection system
(see Figure 7 for the waste discharge arrangements).
5-7
-------
- Building 130 currently has three tanks containing concentrated
stripping solutions, two of which are Aberdeen Strip
(nonphenolic-based); the third tank contains B and B strip, which
is a cresol-based paint stripper. Parts which have been soaked in
any one of these three tanks are rinsed in one common hot water
rinse tank which is connected to the phenol waste collection
system (see Figure 8 for waste discharge arrangements).
- Building 409 has one stripping tank that contains a
nonphenolic-based compound (Aberdeen Strip). This tank is used
exclusively for Al parts. An intermediate step or manual spray
rinse (such as previously described for operations in Bldg. 129)
is not utilized within this process. An adjacent rinse tank
containing hot water with air agitation is the only means for
dragout rinsing from each workpiece withdrawn from this tank.
(See Figure 9 for the sump and piping arrangements at Building
409.)
Paint stripping of steel parts is also performed in either of two hot
alkali tanks, with an adjacent hot water rinse tank.
WASTE STREAM DESCRIPTION
Listed wastes F002 and F004, which contain varying percentages of the
constituents methylene chloride, phenol, cresol, and formic acid (the
latter an Appendix VIII listed constituent), are generated principally
from two sources:
(1) Rinse waters used to remove the dragout of chemical stripping
formulations from paint stripping tanks in Buildings 129, 130,
and 409.
(2) Periodic discharges of the spent paint stripping solvents and
associated paint sludges from their respective tanks resulting
from excessive buildup of paint sludges in these tanks. This
usually occurs twice a year during plant turnaround times (July
and December).
Treatment of wastes in item (1) is accomplished in the IWTP as described
below. The waste discharges in Item (2) are currently sent offsite for
disposal in hazardous waste landfills.
5-8
-------
Data on the flow and composition of wastes under item (1) are
limited. The available data are presented below:1
Avg. wastewater flow
Building No. (gallons per day) Avq. phenol concentration (mq/1)
129 Data not available Data not available
130 3A000 gallons/week2 225
409 964 92
The volume of spent solvents discharged under item (2) can be
estimated from data in Table 2. The composition of these wastes at the
time of discharge is variable, but the basic constituents and ranges of
concentration to be expected are shown in Tables 13 and 14.
CURRENT WASTE MANAGEMENT PROFILE
At the DOD installation, the hazardous spent solvent wastes discussed
above are currently managed, as described in the following section.
Spent Solvent-Bearing Wastewater Treatment at the IWTP
The IWTP complex at the DOD installation is described in Section 4.
Among the five wastewater streams treated at this facility are phenolic-
and other organics-bearing wastewaters. These wastewaters are treated as
shown below.
Wastewaters containing phenolic and other organic compounds are
presently treated in a separate biological pretreatment facility in the
IWTP. The treatment steps include:
1. Influent pumping to the biological treatment system.
2. Aerated flow equalization in a 22,500-gallon basin.
3. Transfer pumping to the aeration basin.
4. Activated sludge treatment, with aeration basin capacity of
approximately 79,000 gallons.
Source: Letter from U.S. Army Environmental Hygiene Agency to M.
Drabkin, April 30, 1987, "Preliminary Data for the Anniston Army
Depot."
This is a batch dump once a week. No total continuous flow data are
available for the phenol-bearing wastewater stream discharged to the
IWTP.
5-9
-------
5. Final clarification within one clarifier, having a capacity of
approximately 4,000 gallons.
6. Sludge from the clarifier recycled to the aeration basin.
7. Discharge of the clarifier overflow to the DOD installation
sanitary treatment system and final effluent discharge under a
State of Alabama NPDES permit.
8. Discharge of waste-activated sludge to the DOD installation
sanitary treatment system.
Disposal of Spent Solvents (F002 and F004 Wastes)
The bulk discharge of spent phenolic and nonphenolic organic paint
stripping solvents is accomplished during July and December of each
year. The various spent solvents in each tank in Buildings 129, 130, and
409 are vacuumed into tank trucks and sent offsite for disposal as
hazardous waste. Paint stripping sludges, which are drawn off the bottom
of each of these tanks, are placed in 55-gallon drums and sent to the
hazardous waste landfill. In 1986, about sixty 55-gallon drums of paint
stripping sludge were shipped to this landfill. Based on two changes of
solvent per year in each paint stripping solvent tank and the data in
Table 13, it is estimated that approximately 21,000 gallons per year of
spent paint stripping solvent are discarded at the DOD installation.
This material is disposed of through a centralized DOD waste disposal
agency at a cost of $5/gallon (as of July 1987). Thus, the annual
disposal cost for this waste is currently estimated as $105,000 per year.
POSTULATED WASTE MINIMIZATION OPTIONS
Waste minimization options for reducing or eliminating the generation
of listed hazardous wastes F002 and F004 from paint stripping operations
in Buildings 129, 130, and 409, were developed under the approved EPA
hierarchy: source reduction options being more desirable and
recycle/reuse options less desirable. Treatment options (not considered
as waste minimization) were only considered if no source reduction or
recycle/reuse options were available for these wastes. The options
considered under these categories are discussed below.
--* Wastewaters Generated in Buildings 129. 130. and 409
Source reduction options
Option (1). Reduction of dragout. In the operation of the solvent
paint stripping process for miscellaneous tank parts in Buildings 129,
130, and 409, the baskets of stripped parts are suspended over the
5-10
-------
solvent tanks for sufficient time to allow excess solvent to drip off the
parts back into the tanks. However, there is an unavoidable dragout of
solvent when odd-shaped parts are placed in the baskets (causing hang-up
of liquid between and in the interstices of these parts), as well as that
caused by solvent retention resulting from surface tension effects. A
deliberate effort could be made to minimize this situation by:
Loading the baskets less full of parts to be stripped;
Stacking the parts appropriately to allow space between them
for the solvent to escape; and
Placing parts containing hollows, crevices, etc., in an
inverted position to allow for more complete drainage.
Recycle/Reuse Options
Option (2). Recovery of solvent. With the dissolved organic levels
in the rinse water waste only in the 250 mg/1 range (as phenol) and the
organic components being mixed in varying proportions in the waste, no
recovery process, e.g., solvent extraction or carbon adsorption, appears
either technically or economically feasible for this purpose.
Treatment Options
Option (3). Modification of phenolic wastewater treatment system.
While treatment is not considered a waste minimization option, the
present treatment system for the phenol-bearing wastewater was studied to
determine if possibilities existed to improve the operation. From phenol
waste stream treatment data supplied for the period from August to
November 1986, it was noted that excursions above the Alabama discharge
limit (approximately 25 percent of the reported data were above the daily
average limit of 0.2 mg/1 for phenol in the treated wastewater), for
phenol occurred primarily during the first part of the week (Monday
through Wednesday). This could be due to a large fluctuation in the
phenol concentration in the influent to the biological treatment system
caused by a large batch dump of this wastewater from Building 130 (a
3,000-gallon dump at the beginning of the work week). This discharge
would significantly affect the phenol concentration of the feed to the
biological treatment system, since this dump is blended with relatively
small flows (under 1,000 gallons per day each) from the other two sources
of phenol-bearing wastewater discharged to the IWTP. Large fluctuations
in the phenol feed concentration appear to affect the biological system
performance, since the system does not fully recover and perform properly
until the latter part of the week.
5-11
-------
A proposed solution to this problem would be to install another 3,000
gallon storage tank in Building 130, and discharge the waste from the
existing 3,000-gallon tank on a uniform basis, i.e., 600 gallons per day,
while the second tank is accumulating waste rinse waters from the solvent
rinsing operations.
Solvent Waste Generated in Buildings 129. 130. and 409
Source reduction options
The following source reduction options were considered to reduce
and/or eliminate solvent wastes generated in Buildings 129, 130, and 409.
Option (4). Continuous solvent cleanup using centrifugation. The
various methylene chloride-based solvents in use in these buildings for
stripping paint from miscellaneous tank parts, are currently replaced
tw'ice a year because of paint sludge buildup in the solvent. The paint
sludge ranges from gelatinous small particle size material to discrete
particles of paint averaging one-quarter inch in size. If this material
can be continuously removed from the solvent as it is formed by the
strfpping action of the latter, then the requirement for replacement of
the solvent on a semiannual basis may be eliminated, and the only solvent
replacement costs would be due to normal evaporation losses, dragout, and
losses resulting from entrainment in the sludge.
One method chosen for consideration as a continuous sludge removal
mechanism is the use of a solid bowl centrifuge. Each of the six tanks
in the three buildings having solvent paint stripping operations would be
equipped with a batch solid bowl centrifuge, feed pump, and a removable
bowl for manual sludge solids cleanout. On a daily basis, each
centrifuge would collect about 1 to 2 gallons of sludge solids.1 At
the end of the shift, the bowl containing the accumulated solids would be
removed and replaced with a spare bowl. The solids would be scraped out
of the bowl and collected in a sludge solids drum. The drums would then
be accumulated over a 90-day period and shipped to a hazardous waste
landfill. Approximately 50 drums of this material would be generated per
year.
Using this WM technique, it is believed that the waste stream of
approximately 21,000 gallons per year of paint stripping solvent
presently disposed of as hazardous waste could be eliminated. However,
in evaluating the economic feasibility of this option, it is assumed that
complete replacement of paint stripping solvents would be required once a
year.
This is considered to be a conservative estimate based on six
55-gallon drums of sludge collected every 6 months from each tank
when the paint solvent tanks are emptied.
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A sample of sludge collected from the bottom of an Aberdeen strip tank in
Building 409, is currently being evaluated by a centrifuge vendor to
determine the required operating parameters for this equipment.1
Option (5). Continuous solvent cleanup using filtration. An
alternative technique for solvent cleanup, assuming that centrifugation
is not effective for this purpose, would be the use of continuous
filtration. In this case, a dual or two-stage unit would be used: the
first stage consisting of a plastic bag filter to remove larger pieces of
paint sludge (down to 25 microns in size) and a second stage consisting
of a porous metal cartridge filter to remove sludge particles down to one
micron in size. Each of these filter units would be housed in a "duplex"
housing equipped with.two of the filter media. This installation would
permit continuous filtration to occur should a bag or cartridge element
become prematurely plugged. Normal filtration operation is envisioned as
requiring a switchover to a fresh bag and cartridge once per day at the
end of the shift. The filter bag and cartridge (loaded with paint
sludge) would be collected in 55-galIon drums and shipped to a hazardous
waste landfill at appropriate intervals. It is believed that use of this
technique would maintain the solvent in a continuously clean condition,
thus eliminating the need for disposal of approximately 21,000 gallons
per year of this material. Again, however, when evaluating the economic
feasibility of this option, it is assumed that complete replacement of
paint stripping solvents would be required once a year.
Recycle/reuse options.
No recycle/reuse options were developed for the paint stripping
solvents in use in Buildings 129, 130, and 409.
PROJECTED COSTS AND SITE AREA REQUIREMENTS FOR THE PROPOSED WM OPTIONS
As additional input for evaluating the overall feasibility of the
proposed WM options discussed above, projected costs (order of magnitude
cost estimates) and any modifications to the plant locations where these
options would be implemented, have been developed, and the results are
summarized in Table 16 for F002 and F004-related options.
A preliminary communication from the centrifuge vendor indicates
that centrifugation can successfully separate the paint sludge from
the solvent, producing a clear solvent product.
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Table 16. Tabulated Projected Costs and Required Site Modifications: WH Options for DOD Installation F002 and F004 Wastes
WH
Option Waste source
Proposed equipment
Option description modifications
Estimated
installed
cost ($}
Estimated annual
direct operating
cost2 ($/yr)
Required site
modifications
Payback
period
(years)
(1) Oragout from painted parts
stripping tanks resulting
in waste rinse waters
(3) Dragout from painted parts
stripping tanks resulting
in waste rinse waters
Modification of paint
stripping operations to
minimize dragout
Modification of discharge
to biological treatment
plant to avoid wide flow
fluctuations
Install second 3.000-gallon
tank in Bldg. 130 to hold
week's rinse water accumula-
tion while full 3,000-gallon
tank is discharging wastfi-
water at metered rate.
8,000
Floor space is believed
to be available for this
tank; no major existing
equipment relocation
would be required.
in
i
(4) Waste paint stripping
solvent disposal
Continuous removal of
paint sludge from
solvent (using a solid
bowl centrifuge) to avoid
necessity of solvent
disposal when sludge
content gets too high
Add a pump and solid bowl
centrifuge to each of the
six paint stripping solvent
tanks; unit operates at
about 5 gpm flow rate.
50.000 5.000 Adequate floor space is
available in front of
each of these stripping
tanks to permit installa-
tion without major exist-
ing equipment relocation.
0.5
(5) Waste paint stripping
solvent disposal
Continuous removal of
paint sludge from
solvent (using a two-
stage filtration unit)
to avoid necessity of
solvent disposal when
sludge content gets
too high
Add a pump and two-stage
filtration unit (first stage
is basket type filter for
large pieces and second stage
is a porous metal filtration
cartridge for micron-size
particles.
60,000 9,000 Adequate floor space is
available in front of
each of these stripping
tanks to permit installa-
tion without major exist-
ing equipment relocation.
0.67
All options shown are source reduction options except for (3), which is a treatment option, i.e., not a WM option.
Other than the cost of replacing spent paint stripping solvent, which is estimated separately.
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There would be no cost involved in implementing the proposed source
reduction options for reducing phenol-bearing wastewater generation. The
alternative option which is revamped handling of phenol-bearing
wastewater (not a WM option) in order to overcome present operating
difficulties of consistently meeting the required treated effluent phenol
levels, would cost about $8,000 to install. There would be no
incremental operating costs, and adequate space is believed to be
available in Building 130 to accommodate the equipment involved.
For those WM options aimed at reducing or eliminating the source of
F002 and F004 solvent wastes, payback periods have been estimated for two
alternatives; these alternatives are presented below:
(a) The use of solid bowl centrifuges installed at each of the six
paint stripping tanks for continuously removing paint sludge.
This would result in an annual savings in purchased solvent cost
of $48,000 if annual replacement of solvent was required instead
of the present semiannual replacement. By discarding spent
paint stripping solvent annually instead of semiannually, annual
hazardous waste disposal costs would be cut in half, i.e., about
$53,000 instead of the currently estimated $105,000. In this
scenario, the estimated payback period would be 50,000/96,000,
or approximately 6 months.
(b) Should centrifucution not be an appropriate treatment for paint
stripping solvent cleanup, the other alternative available is
the use of two-stage cartridge/bag filtration equipment
installed at each of the six solvent tanks for continuously
removing paint sludge. If solvent were replaced annually
instead of semiannually, the annual savings in purchased solvent
cost would be $45,000. In this scenario, using $53,000 per year
as the net savings in waste paint stripping solvent disposal,
the estimated payback period would be 60,000/89,000, or
approximately 8 months.
Since the payback period for these two proposed WM options is
essentially the same, choice of the appropriate option would depend on
their technical feasibility. Assuming that both options are technically
feasible, the audit team believes that the continuous centrifugation mode
of paint stripping solvent cleanup is the preferred option from the
standpoint of ease of operation. Over the long term, however, the lower
maintenance cost of the filtration option could be the deciding factor in
the choice of one of these WM techniques.
5-15
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SUMMARY AND DISCUSSION
The DOD installation currently generates F002 and F004 spent paint
stripping solvent wastes in three main areas: Buildings 129, 130, and
409. These hazardous waste materials are discharged as both contaminated
rinse waters from the paint stripping operations performed on tank parts
and as spent halogenated solvent formulations from the stripping tanks
themselves. The IWTP is presently able to handle treatment of the
wastewaters so that they can be discharged under an NPDES permit (based
on meeting a phenol level in the treated wast.ewater). Occasionally,
sudden surges in wastewater discharges from Building 130 will cause
difficulties in the ability of the IWTP to meet the phenol level in the
treated discharge. The spent paint stripping solvents themselves are
presently not reclaimed, but are periodically discharged (along with
paint sludges) as hazardous wastes for disposal.
, In summary, the results of the WMA conducted at Buildings 129, 130,
and 409 of the DOD installation by the EPA-sponsored audit team, clearly
indicated that reduction of the organic waste treatment load at the IWTP
was available through a source reduction option (minimization of paint
stripping solvent dragout by revised operating procedures) and a non-WM
option (revamped method of discharge of phenols-bearing wastewaters from
Building 130). Additionally, two source reduction options appeared to be
available to significantly reduce waste F002 and F004 solvent discharges
from these three locations, through the use of continuous centrifugation
or filtration operations (to continuously remove paint sludge generated
by the stripped tank parts) at. the six paint stripping locations in these
buildings. Specifically, paint stripping solvent replacement can be
conducted on an annual basis instead of a semiannual basis, thus halving
the annual F002 and F004 waste disposal cost. Using a continuous
centrifuge process, a preliminary estimate of the payback period would be
approximately 6 months. If a continuous filtration process were used, a
prelminary estimate of the payback period would be about 8 months.
Preliminary testing by a centrifuge vendor of a sample of paint
sludge-loaded stripping solvent indicates that this process is
technically feasible.
5-16
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SECTION 6
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