United States
                   Environmental Protection
                   Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
                   Research and Development
EPA/600/S2-88/010  Mar. 1988
&EPA         Project Summary
                   Waste Minimization Audit
                   Report:  Case Studies  of
                   Minimization of Solvent
                   Wastes and  Electroplating
                   Wastes at a  DOD  Installation
                   Marvin Drabkin and Paul Sylvestri
                    The U.S. Environmental Protection
                   Agency (EPA) is encouraging hazard-
                   ous waste generators to develop pro-
                   grams to reduce the generation of
                   hazardous waste. To foster such pro-
                   grams,  the  Agency's   Office of
                   Research and Development Hazardous
                   Waste Engineering Research Labora-
                   tory (ORD/HWERL) is supporting the
                   development and evaluation of a model
                   hazardous waste minimization  audit
                   (WMA) procedure using the EPA hier-
                   archy of waste minimization  (WM)
                   options,  with  source reduction  being
                   more desirable and recycle/reuse less
                   desirable. Treatment options, although
                   not considered WM, are  evaluated if
                   neither of the former alternatives  is
                   available. The WMA procedure was
                   tested initially in several facilities in
                   1986. WM As were conducted at gener-
                   ators of a number of generic hazardous
                   wastes,  including corrosives, heavy
                   metals, spent solvents, and cyanides.
                    In 1987. the HWERL WMA program
                   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 treat-
                   ment sludges from electroplating oper-
                   ations). This Project Summary covers
                   a WMA carried out  at a  DOD instal-
                   lation responsible for the rehabilitation
of worn Army tanks. This audit was
aimed at developing WM options for
F002, F004, and F006 wastes.
  The WMA carried out at the DOD
installation's electroplating facility
resulted in the development of three
source reduction options and two
recycle/reuse options for cadmium/
cyanide waste as well as two source
reduction options for chromium waste.
Successful implementation of appro-
priate combinations of these options
could  result in  the DOD installation
being able to achieve EPA delisting of
the F006 wastewater treated sludge.
Payback  period  for the incremental
investment  needed to achieve these
WM results, could range from four
months to 1.9 years depending on the
choice of options. Savings in present
F006  waste disposal costs could
amount to $120,000 annually.
  The  WMA carried out at the DOD
installation's paint stripping solvent
facilities  resulted in two alternative
source reduction options being deve-
loped by the audit team. Implementa-
tion of either of these two options could
result in payback period for the incre-
mental investment involved ranging
from  6 to 8 months with savings in
waste solvent  disposal  costs  of
$53,000 annually.
This Project Summary was developed
by EPA's Hazardous Waste Engineering
Research Laboratory, Cincinnati, OH,
to announce key findings of  the

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research project that is fully documented
in a separate report of the same title (see
Project  Report ordering information at
back).

Introduction
  The national policy  objectives estab-
lished 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 expedi-
tiously 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 under-
taken a project  to develop and test  a
waste minimization audit (WMA) proce-
dure. It is envisioned that such a proce-
dure would be useful to generators of
hazardous  waste as  they search for
waste  minimization  alternatives.  The
present  HWERL  project  expands on an
audit procedure developed and tested in
1986 by conducting additional WMAs in
cooperating industrial and government
facilities. This project  is one of several
current audit efforts being supported by
HWERL.
  This study presents the elements of a
WM program, of which the audit proce-
dure is a central component and includes
details  of the  WMA procedure, its
development, and its final recommended
form. A case study is presented using
this WMA procedure, and covers audits
performed at a  DOO installation that
includes facilities which generate listed
wastes  F002 and  F004 as  well  as  a
facility  which generates  listed waste
F006. Findings and conclusions resulting
from these audits are presented below.


Description of the WMA
Procedure
  The function of the WMA procedure
is to force the use of an orderly step-
by-step  procedure for conducting an
audit at a host  site. The  initial WMA
procedure was developed in earlier work,
and  was  further refined during  the
course  of  the present EPA-sponsored
audit effort. This  procedure is applicable
to the development of both categories of
WM options (source  reduction  and
recycling/reuse) as  well as to  the
development of treatment options.
  The team employed in carrying out the
audit described  in the full report was
composed entirely  of employees of an
outside consulting/engineering firm.
Following  selection  of the host facility
there  were  eight  sequential  steps
executed by the audit team:

  1.  Preparation for the audit.

  2.  Host site pre-audit visit.
  3.  Waste stream selection.

  4.  Host site waste minimization audit
     visit.

  5.  Generation of WM options.
  6.  Preliminary WM options evaluation
     (including preparation of prelimi-
     nary cost estimates) and ranking of
     options  in three categories (effec-
     tiveness, extent of current use, and
     potential for future application).
  7.  Presentation, discussion, and joint
     review  of options  with  plant
     personnel.

  8.  Final report preparation and pres-
     entation to host site managmeent.

This procedure was followed in carrying
out the WMAs summarized below.

Results of the WMA
Conducted at a Generator of
F002 and F004 Waste: Audit
at a DOD Installation Paint
Stripping Facility
  A DOD  installation in  the  South,  a
portion of  whose facilities is devoted to
the rehabilitation of worn Army tanks
was studied in a WMA for the reduction
of F002 and F004 wastes. These listed
F wastes are partially defined in 40 CFK
261.32 as follows:

• F002: Spent halogenated solvents
   including methylene chloride.
• F004: Spent non-halogenated sol-
   vents including cresols and cresylic
   acid.

At three buildings in the  DOD installa-
tion, tank  part  paint stripping facilities
using methylene chloride solvent formu-
lationsfcontaining phenolic-type constit-
uents to enhance solvent action), gener-
ate F002  and F004 wastes. F002 and
F004 wastes include:

• Approximately 20,000 gallons  per
   year of spent methylene  chloride-
   based  paint stripping  solvent and
   about sixty, 55-gallon drums of paint
   sludge  are generated  in the paint
   stripping operations and sent offsite
   for hazardous waste disposal. Spent
   solvents are presently disposed of in
   bulk approximately every 6 months.
   Drummed  hazardous paint sludges
   are shipped offsite within 90 days of
   accumulation.

• Wastewaters  from stripped parts
   rinsing operations  are  sent to the
   onsite wastewater treatment  plant
   where biological treatment is used to
   reduce phenol level to  meet NPDES
   permit  requirements   prior  to
   discharge.

  The audit team studied possible source
reduction and recycle/reuse options for
these wastes. The focus of this effort was
primarily on ways to prolong the life of
the paint stripping solvents as the most
effective  short-term options.  The long-
term waste  reduction options,  i.e.,
development  of  non-solvent formula-
tions  and other paint  removal tech-
niques,  could  not  be meaningfully
addressed in this study.
  The most promising source reduction
options for paint stripping solvent waste
reduction were:

• Continuous centrifugation of the paint
   stripping solvent to remove paint
   sludge as it is generated  thus prevent-
   ing  buildup of this  sludge in the
   stripping tanks and  significantly
   extending the life of the  solvent.

• As an alternative to continuous cen-
   trifugation of the solvent, continuous
   2-stage basket/cartridge filtration of
   the solvent to prevent  paint sludge
   buildup.

  In summary, it is believed that success-
ful  implementation of either of these
options could result in solvent life being
extended to at least one  year prior to
replacement. In this regard, a small scale
test by a centrifuge vendor on a sample
of spent solvent heavily loaded with paint
sludge, indicated that clear solvent could
be produced by this technique. Each of
the six main paint stripping solvent tanks
at the facility  would be equipped with
either a solid-bowl type centrifuge or a
basket/cartridge type  2-stage filter.
Table 1  summarizes the results of  the
preliminary technical and  economic
feasibiliy study  of these  two options.
Annual waste  solvent disposal  cost
would  be  cut  in half (approximately
$50,000 per  year savings) if either of
these two options were adopted, with

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Table 1.
 Tabulated Projected Costs and Required Site Modifications: WM Options for DOD Installation F002 and F004 Wastes
WM
Option^
Waste Source Option Description
Proposed Equipment
Modifications
Estimated
Estimated Annual
Installed Direct Operating
Cost($) Cost*($/yr)
Required Site
Modifications
Payback
Period
(years)
   (1)
   12)
Waste paint
Continuous removal
          stripping solvent of paint sludge from
          disposal
Waste paint
                   Add a pump and solid
                   bowl centrifuge to each
               solvent (using a solid  of the six paint stripping
bowl centrifuge).
Solvent replaced
annually.


Continuous removal
                                            solvent tanks; unit
                                            operates at about 5 gpm
                                            flow rate.
                   Add a pump and two-
                   stage filtration unit to
solvent (using a two-  each of the six paint
stage filtration unit),   stripping solvent tanks
                   (first stage is basket type
                   filter for large pieces and
                   second stage is a porous
                   metal filtration cartridge
                   for micron-size particles).
          stripping solvent of paint sludge from
          disposal

                         Solvent replaced
                         annually.
50,000       5,000      Adequate floor space is   0.5
                        available in front of
                        each of these stripping
                        tanks to permit
                        installation without
                        major existing
                        equipment relocation.

60,000       9,000      Adequate floor space is   0.67
                        available in front of
                        each of these stripping
                        tanks to permit
                        installation without
                        major existing
                        equipment relocation.
1AII options shown are source reduction options.
2Other than the cost of replacing spent paint stripping solvent, which is estimated separately.
payback periods ranging from 0.5 to 0.7
year.


Results of the WMA
Conducted at a Generator of
F006 Waste: Audit at the DOD
Installation Electroplating
Facilities
  Electroplating operations at the DOD
installation are conducted in one building
and include cadmium plating of miscel-
laneous cleaned  and/or  remachined
tank parts using cadmium/cyanide (Cd/
CN) solutions  in  either an  automatic
barrel  plating  line or  a  manual  rack
plating  line.  Chromium (Cr)  plating of
appropriately prepared tank  parts is
conducted in  a rack  plating  line. Both
plating  operations are  fairly standard-
ized.
  The  facility  has been  experiencing
significant problems in  meeting NPDES
permit limitations for Cd and CN in the
treated wastewater discharge. Thus, the
audit team focused primarily on waste
reduction options which could reduce or
eliminate Cd and CN levels in  the  raw
waste (principally rinsewaters from both
Cd  plating lines). Approximately 2,000
gallons  per  day of these wastewaters
typically containing 20  mg/l  of Cd  and
25  mg/l CN are discharged from  the
electroplating  facility.  About  35,000
gallons  per day of  Cr-bearing waste
averaging 110 to 120 mg/l Cr  are  also
discharged from this facility.
                                 A study of the electroplating operations
                               that  generate F006  waste (including
                               discussions between the audit team and
                               plant personnel), led the audit team to
                               develop a total of five WM  options for
                               Cd/CN plating-related waste  and two
                               WM options for Cr plating-related waste.
                               These  options include  commercially
                               demonstrated processing techniques
                               designed to minimize or eliminate Cd, Cr,
                               and CN levels in the rinsewater wastes
                               as well as  reducing  the amounts  of
                               wastewater. These options together with
                               their estimated  capital and operating
                               costs are summarized  in Table 2. One
                               proposed source reduction option: elec-
                               trolytic reverse current destruction of CN
                               (both simple and complexed) in the still
                               rinse tanks of the two Cd plating lines
                               during  the plant downtime period,  is
                               currently being evaluated at the facility.
                               One  proposed recycle/reuse  option:
                               recovery of Cd from the two plating lines'
                               still rinse tanks, has since been  imple-
                               mented and appears to have  resulted in
                               the  facility being able to consistently
                               meet the Cd limit in their NPDES permit.
                                   It is believed that  successful imple-
                               mentation of appropriate combinations of
                               these WM options could  result  in the
                               DOD  installation being able  to achieve
                               EPA delisting of the F006 wastewater
                               treatment sludge as well as meeting Cd
                               and  CN permit  limits in the NPDES
                               discharge.  Payback  periods  for the
                               incremental investment involved range
                               from 6 months to 1.9 years.  Savings  in
                               the present F006 waste disposal  costs
                                                         could amount to $120,000 annually if the
                                                         F006 waste can be delisted.

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Table 2. Tabulated Projected Costs: WM Options for DOD Installation F006 Wastes1
WM Option Proposed Equipment
Option Waste Source Type Option Description Modifications
(a)(1) CD/CN Barrel Plating
Line
fa)(2) Cd/CN Manual
Plating Line
(b)( 1 ) Cd/CN Barrel Plating
Line
(b)(2) Cd/CN Manual
Plating Line
(c)(1) Cd/CN Manual
Plating Line
(c)(2) Chromium Manual
Plating Line
fd) Both Cd/CN Plating
Lines
fej(l) Cd/CN Barrel Plating
Line
(e)(2) Cd/CN Manual
Plating Line
(fj Chromium Manual
Plating Line
(g) Chromium Manual
Plating tine
Source
reduction
Source
reduction
Source
reduction
Source
reduction
Source
reduction
Source
reduction
Recycle/
reuse
Recycle/
reuse
Recycle/
reuse
Source
reduction
Source
reduction
Use of electroclean rinse
waters as feed to pickling
rinse water tank
Use of electroclean rinse
waters as feed to pickling
rinse water tank
Destruction of cyanides
in still rinse tank
Destruction of cyanides
in still rinse tank
Improved dragout
recovery;
drain board, spray/fog
rinsing nozzles over
plating tank
Improved dragout
recovery; drain
board, spray/fog
rinsing
Evaporation of Cd/CN
rinse water discharge
and recycle to
both plating lines
in appropriate
quantities to
maintain individual
plating bath
water balances
Plating out of cadmium
in still rinse tank
Plating out of cadmium
in still rinse tank
Improved dragout
recovery:
replacement of running
rinse tank with spray
chamber
Reduction of chromium
metal losses from
hood vents over
plating tanks
Water piping and pump
Water piping and pump
Insertion ofSS cathodes and
anodes in still rinse tank
and operation in a CN
destruction mode during
plating line downtime
Insertion ofSS cathodes and
anodes in still rinse tank
and operation in a CN
destruction mode during
plating line downtime
Add drain board between Cd
plating tank and still rinse
tank; install spray/fog rinse
Add drain board between Cr
plating tank and still rinse
tank; install spray/fog rinse
nozzles over plating tank
Install evaporation unit and
auxiliaries in Building 114
basement near Cd/CN
waste sump
Insertion of SS cathodes and
anodes in still rinse tank
to operate in a Cd plating
mode during plating line
downtime
Insertion ofSS cathodes and
anodes in still rinse tank
to operate in a Cd plating
mode during plating line
downtime
Install suitable banks of
spray nozzles in empty
running rinse tank
Add layer of plastic balls
on surface of chromium
plating tanks
Estimated Estimated Annual
Installed Operating Cost
Cost {$)' l$/yr)
$ 1,000
1,000
2.000
2.000
1,500
1,500
79,000
Use the
same
equipment
as in (b)
Use the
same
equipment
as in (b)
5,000
Nil
$ 500
500
10,000
10,000
1,000
1,000
27.000
20,000
2O.OOO
2,000
Nil
^Order of magnitude costs (± 50 percent accuracy).

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     M. Drabkin and P. Sylvestri are with Versar, Inc., Springfield, VA 22151.
     Harry F. Freeman is the EPA Project Officer (see below).
     The complete report, entitled "Waste Minimization Audit Report: Case Studies
       of Minimization of Solvent  Wastes and Electroplating Wastes at a DOD
       Installation," {Order No. PB 88-166 780/AS; Cost: $14.95, subject to change)
       will be available only from:
             National Technical Information Service
             5285 Port Royal Road
             Springfield. VA 22161
             Telephone: 703-487-4650
     The EPA Project Officer can be  contacted at:
             Hazardous Waste Engineering Research Laboratory
             U.S. Environmental Protection Agency
             Cincinnati,  OH 45268
                                                                                                    62SOICO'
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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