Tip Sheet #4

WASTE ORIGIN: Solvent Parts Cleaning Operations
WASTE TYPES: Petroleum-based Solvents, Volatile Organic Compound (VOC) Air Emissions, and Soils

WASTE REDUCTION AND RECYCLING METHODS:

• Install lids or silhouettes on tanks, and cover tanks when not in use.
• Use less toxic solvents (e.g., dibasic acid esters, terpenes, amines, alcohols).
• Substitute less hazardous solvent degreasers (e.g., petroleum solvents instead of chlorinated solvents).
  
• Replace solvents with aqueous cleaners.
• Replace solvents with mechanical or thermal alternatives (e.g., air blast systems, dry stripping, and cleaning with blasting media).
• Standardize type of solvent used in all operations.
• Consolidate cold cleaning operations into centralized vapor degreasing operation.
• Locate cold cleaning tanks away from heat sources.
• Minimize vapor diffusion:
  • Check parts for excessive water contamination;
  • Cover water separator;
  • Check water jacket for proper water flow and temperature on outside of degreaser;
  • Extend freeboard;
  • Use cold traps above freeboard chillers;
  • Locate degreasers away from drafts, windows, fans, or use baffles (air flow over tank should not exceed 131 feet per minute).
• Maintain proper solvent level in sump.
• Control the amount of heat supplied to vapor degreasers.
• Install safety limit switches (condenser flow switch and shut-off device for sump heat and a spray safety switch).
• Avoid spraying parts above the vapor zone or cooling jacket.
• Avoid solvent vapor drag-out by controlling speed of withdrawal (less than 11 feet per minute).
• Allow sufficient time in the degreaser.
• Limit workload size (use baskets with an area less than 50 percent of degreaser opening).
• Avoid cross-contamination of solvents (e.g., 1,1,1-Trichloroethane and
• trichloroethylene).
• Use appropriate makeup solutions for solvent bath.
• Remove sludge from solvent tanks frequently.
• Extend solvent life by pre-cleaning parts by wiping, using air blowers, or pre-dipping in cold mineral spirits dip.
• Reclaim or recover solvent on- or off-site (gravity separation, filtration, distillation, fuel
• use).
• Distribute parts on rack to allow good cleaning and minimize solvent hold-up.
• Slow speed of parts removal from vapor zone.
• Rotate parts to allow condensed solvent drop-off.

Sources

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