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Stemco LP

Year Submitted: 2008

Process: Process Liquid Filtration

Industry: Automotive Parts Manufacturer

Wastes Reduced: Zinc

Location: Longview TX

No. of employees: 350

Contact: Larry Minton

Phone: 903 758 9981


Stemco operates a zinc phosphatizing process as a part of our elastomeric seal production operation. To maintain product quality, we were emptying our zinc phosphate tank every two weeks. Precipitated solids were causing non-bonds on our rubber/metal parts.

P2 Application:

A filter press was added to remove the precipitated solids from the zinc phosphate bath. The filter press allowed us to extend the life of the zinc phosphate solution from 2 weeks to 6 months. Zinc phosphate usage was reduced by 59 % with a cost savings of $15,257/year. Zinc phosphate waste was reduced 95 % with a cost savings of $2,850/year. The cost of the filter press was $12,186 which gave us an 8 month payout on the investment.

  • Total Cost Savings: $18,000.00
  • Comments: The cost of the filter press was $12,186 which gave us an 8 month payout on the investment.

Details of Reductions

  • 21,348.0 - lbs of   Zinc Phosphate
    Comments: Drums of material for disposal reduced from approximately 40 per year to 4 per year. Approximate weight of a drum = 593 pounds(40-4=36x593=21,348 pounds reduced per year). Each drum cost $75 for disposal. Actual savings noted was $2,800 in disposal costs.
  • 11,267.0 - lbs of   Zinc Phosphate
    Comments: Purchased 46 drums per year prior to P2 implementation. Afterward purchased 27 drums per year. Each drum of zinc phosphate cost $803. (46-27=19x$803 = $15,257) Each drum weight is approximately 593 pounds. (593 x 19 = 11,267)
Source: Zero Waste Network

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