INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

CASE STUDY # 140

1.   Headline:  Process modifications in a machine shop results
     in savings.

2.   Background:  See below

3.   Cleaner Production Principle:  process modification

4.   Description of Cleaner Production Application:  A six tank
     metal surface preparation (phosphating) and cleaning
     process, a filtration system and a residuals concentration
     process replaces a manual process, using acetone, for
     removing surface oils from metal parts.  The wiped parts
     had been subsequently cleaned in three rinse tanks.  The
     new process uses counterflow to efficiently utilize the
     rinse waters.  The residuals are concentrated by liquid
     evaporation and sludge concentration, using steam heat
     from the boiler in the winter and a new gas boiler in the
     summer.  A distillation unit permits additional savings
     through acetone and other solvent recovery and reuse.

     Material/Energy Balance and Substitutions

     FEEDSTOCKS: Water, acetone, chemicals

     WASTES: Wastewaters, acetone

     MEDIUM: Liquid

5.   Economics

                              CAPITAL COST:
                              $38,967.68

                              OPERATION/MAINTENANCE:  $500/yr
                              gas per boiler

                              MONTHS TO RECOVER:     Not
                              reported

                              DISPOSAL & FEEDSTOCK:
                              $14,418/yr

6.   Advantages

     FEEDSTOCK REDUCTION: 45% reduction in acetone, 96% in
     water, and 50% in chemicals

     WASTE PRODUCTION: Reduced to less than 500 lbs/yr

     IMPACT: The new metal fabrication system addresses
     previous operational problems, reduces material costs, oil
     accumulation, labor requirements, and residual waste
     disposal costs.  Hazardous sludge generation is reduced to
     less than one 55 gallon drum.


7.   Constraints:  No information provided.

8.   Contact and Citation:  "Case Summaries of Waste Reduction
     by Industries in the Southeast", Schecter, Roger N., Hunt,
     Gary, July, 1989, Page 40.

9.   Keywords:  United States, USA, metal, machine shop,
     process modification, cleaning, surface preparation,
     filtration, rinsing, distillation, solvent, acetone, ISIC
     3499.

10.  Reviewer's Comments:  This case study part of a core
     collection of case studies from North Carolina, USA and
     was originally abstracted for the US Environmental
     Protection Agency's Pollution Prevention Information
     Clearinghouse.  It underwent a UNEP IE funded technical
     review in 1994 for quality and completeness.  It was
     edited for the ICPIC diskette in July 1995.


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