United States
                         Environmental Protection
                                      Risk Reduction
                                      Engineering Laboratory
                                      Cincinnati OH 45268
                         Research and Development
                                      EPA/600/S-92/013 June 1992
                         Waste Minimization Assessment for a
                   Manufacturer of Water Analysis Instrumentation

                              F. William Kirsch and J. Clifford Maginn*
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small- and medium-sized manufacturers
who want to minimize their generation of hazardous waste but
who lack the expertise to do so. Waste Minimization Assess-
ment Centers (WMACS) were established at selected universi-
ties and procedures were adapted from the EPA Waste Minimi-
zation Opportunity Assessment Manual (EPAJ625/7-B8/003, July
1988).  The  WMAC team  at Colorado State University per-
formed an assessment at a plant manufacturing instruments
for water analysis—approximately 50,000 units/yr. Primary op-
erations  include production of cabinets and  assembly of
instruments. Sheet metal and small metal parts are usually
chemically treated for desired finishes. Cabinet fabrication in-
volves  forming sheet metal, drilling, surface preparation, and
painting. Most manufacturing involves assembly,  and many of
the electronic and optical  components are purchased from
external suppliers. The team's report, detailing  findings and
recommendations, indicated that most waste is generated as
spent reagents and rinse water from metal  surface finishing,
but greatest savings could be obtained by filtering and pasteur-
izing metal cutting fluid for  recycle and separating its organic
and aqueous phases when disposal becomes necessary.

This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory, Cincin-
nati, OH, to announce key findings of an ongoing research
project that  is fully documented in a separate  report of the
same title available from the authors.
The amount of hazardous waste generated by industrial plants
has become an increasingly costly problem for manufacturers
  University City Science Center, Philadelphia, PA 19104
                         and an additional stress on the environment. One solution to
                         the problem of hazardous waste is to reduce or eliminate the
                         waste at its source.

                         University City Science Center (Philadelphia, PA) has begun a
                         pilot project to assist small- and medium-size  manufacturers
                         who want to minimize their formation of hazardous waste but
                         who lack the in-house expertise to do so. Under agreement
                         with EPA's Risk Reduction Engineering  Laboratory, the Sci-
                         ence Center has established three WMACs. This assessment
                         was done by engineering faculty and students at Colorado
                         State University's (Fort Collins) WMAC.

                         The waste minimization assessments are done for small- and
                         medium-size manufacturers at no out-of-pocket cost to  the
                         client. To  qualify for the assessment, each client must fall
                         within Standard Industrial Classification Code 20-39, have gross
                         annual sales not exceeding $50 million, employ no more than
                         500 persons, and  lack in-house expertise in waste minimiza-
                         tion. The potential benefits of the pilot project include minimiza-
                         tion of the amount of waste generated by manufacturers, re-
                         duced waste treatment and disposal costs for participating
                         plants, valuable experience for graduate and undergraduate
                         students who participate  in the program, and a cleaner envi-
                         ronment without more regulations  and higher costs for manu-

                         Methodology of Assessments
                         The waste minimization assessments require several site visits
                         to each client served. In general, the WMACs follow the proce-
                         dures outlined in  the EPA Waste Minimization Opportunity
                         Assessment Manual (EPA/625/7-88/003, July 1988). The WMAC
                         staff locate the sources of hazardous waste in each plant and
                         identify the current disposal or treatment methods and their

                                                  i£3) Printed on Recycled Paper

associated costs. They then identify and analyze a variety of
ways to reduce or eliminate the waste. Specific measures to
achieve that goal are recommended, and the essential sup-
porting technological and economic information is developed.
Finally, a confidential report which details the WMAC's findings
and recommendations including cost savings, implementation
costs, and payback times is prepared for each client.

Plant Background
The plant produces instruments used for water analysis. The
plant operates 4,394 hr/yr to produce  approximately 50,000

Manufacturing Process
The plant  produces colorimeters, spectrophotometers,  pH
meters, Ion-selective electrodes, t'rtrators, BOD and COD in-
struments and reagents, turbidimeters, controllers and test kits.
Most manufacturing involves assembly with many components
purchased from external suppliers. Other manufacturing opera-
tions are sheet-metal forming, machining, metal surface prepa-
ration, soldering, and painting. Electronic components are wave-
soldered onto prefabricated circuit boards. (Circuit boards are
obtained from outside suppliers).

Metal forming and machining operations result in spent hydrau-
lic oil and  spent cutting  fluid,  both shipped for  disposal by
incineration. Spent  reagents from  steel surface  preparation
(alkaline detergent,  phosphoric acid descaler, and iron phos-
phate conversion coatings) and  aluminum surface preparation
(caustic, suKuric acid, and ferric sulfate)  are combined with
rinse water, treated for Ph adjustment by caustic addition, and
sawered as Industrial wastewater.

Spent solvent from degreasing operations is sent to a recycler,
and recovered solvent is purchased for use in the plant. Waste
solvents from a chemical laboratory and waste solvent-based
paints and thinners are disposed of as hazardous waste.

Existing Waste Management Practices
  • The plant returns waste solder to  the  supplier and
    sells metal chips and cuttings as scrap.
  • A dry booth is used for painting to avoid generation of
    contaminated rinse water and  reduce generation of
    spent solvents.
  * An internal drainage system eliminates miscellaneous
    discharges  to the sewer, and  screens placed over
    internal drains prevent entry of melted chips and turn-
  * In the anodizing line, parts are rinsed over a black dye
    tank to reduce drag-out to the rinse tank, extending
    the life of the rinse water.
Waste Minimization Opportunities
The type of waste currently generated by the plant, the source
of the waste, the quantity of the waste, and the annual man-
agement costs are given in Table 1.

Table 2 shows the opportunities for waste minimization that the
WMAC  team recommended for  the plant. The type of waste,
the minimization opportunity, the possible waste reduction and
associated savings, and the implementation cost along with the
payback time are given in the table. The quantities of hazard-
ous waste currently generated by the plant and possible waste
reduction  depend  on the production  level of  the plant. All
values should be considered in that context.

It should be noted that, in  most cases, the economic savings of
the minimization opportunities  result from the need for less raw
material and from reduced present and future costs associated
with hazardous waste treatment and disposal. Other savings
not quantifiable by this study include a wide variety of possible
future costs related to changing  emissions  standards, liability,
and employee health. It should also be noted that the savings
given for each opportunity reflect the savings achievable when
implementing each waste minimization opportunity  indepen-
dently and do  not reflect duplication  of savings that  would
result when the opportunities are implemented in a package.

Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, two additional measures were considered.
These measures were not completely analyzed because of
insufficient data or minimal savings as indicated below.  They
were brought to the plant's attention for future reference, how-
ever, since these approaches to  waste reduction may increase
in attractiveness with  changing plant conditions.

  • Replace  solvent-based paint with  electrostatic coat-
    ing, which might  be used  on 70%  of painted produc-
    tion. However, investment  cost for such a  system
    would be high with a long payback, since present cost
    for disposal of waste  paint and thinner is small.

  • Re-establish a cooperative  approach to cutting fluid
    management. A  balance  should be struck between
    the  desire to minimize waste cutting fluid, which  pro-
    motes  recycling, and the need for product  quality,
    which does not emphasize recycling.

This research brief  summarizes a part of the work done under
Cooperative Agreement No. CR-814903 by  the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Emma Lou

Table 1, Summary of Current Waste Generation
Waste Generated
Spent cutting fluid
Spent hydraulic oil
Waste paint and thinner
Spent reagent solutions
Source of Waste
Cutting fluid is discarded when bacteria buildup has become excessive
or viscosity difficult to control. Spent fluid is disposed of by incineration.
Hydraulic oil is filtered and reused. When it can no longer be used, it
is disposed of by incineration.
Paint spray nozzle cleaning operations result in waste paint and thinner.
Steel surface preparation and aluminum anodizing result in spent reagent
600 gal
450 gal
150 gal
487,500 gal
and rinse waters
     solutions. Spent detergents, descaler, conversion coatings, caustic, ferric
     sulfate, and sulfuric add solutions and rinse waters are pH-adjusted and
     discharged as industrial wastewater.
Spent solder flux
Spent degreaser solvent
The flux bath is drained when solderability approaches an unacceptable
level. The spent flux is disposed of as hazardous waste.
Spent solvent from degreasing operations is shipped to a recycler.
Recovered solvent is purchased for use in the process.
300 gal
20 gal
Table 2.  Summary of Recommended Waste Minimization Opportunities
Waste Generated
Spent cutting fluid
Minimization Opportunity
Use existing equipment to filter and pasteurize
Annual Waste Reduction
Quantity Percent
300 50
Spent hydraulic oil
spent cutting fluid for recycling. When disposal is
needed, treat the spent fluid with sulfuric acid.
Neutralize and sewer the resulting aqueous phase
and dispose of the organic phase as hazardous

Ship the spent hydraulic oil to a recycler rather than
a disposal facility for cost savings.
                                                                                              •U.S. Government Printing Office: 1992— 648-080/60014

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