Metals and Welding Laboratory
February 26, 2015 By Peaks to Prairies

Waste Stream Assessment:

Estimate what percentages of your waste fall into these common categories.  Add your own categories if necessary.

___% Metal ___% Packaging and Containers
___% Finishing Chemicals* ___% Other

*Surface preparation – paints, strippers, solvents, waste water

Now look at where you can reduce waste, reuse materials or recycle. Try to make use of metal working materials made from recycled materials. Use environmentally friendly products when possible. When dealing with products that can only be disposed of, choose the least hazardous option.

Use this checklist to identify possible problem areas.

Metal Finishing Chemical Wastes

All finishing chemicals – Do You?
  • Keep product lids secure and closed tightly to prevent spills and evaporation.
  • Store containers off the ground and in an area where they won’t corrode. (Store over spill containing pallets when possible.)
  • Remember that any water contaminated with such chemical waste becomes waste itself.
  • Ask your local painting supply company about regulations in your area, recycling opportunities and proper disposal methods.
Cutting fluids – Do You?
  • Conserve as much as possible.
  • Filter solid matter that builds up in fluid.
  • Follow all manufacturers recommendations on fluid use and maintenance.
  • Research and choose the optimum fluid for your common processes and materials.
  • Select a fluid which may be easily recycled or select a fluid that is least harmful to the environment.
Metal coating materials – Do You?
  • Determine if coating material is hazardous. Dry paint may not be considered hazardous.
  • Use coating with high solid content (usually 35% or more), as they require fewer coats.
  • Teach students proper and efficient application techniques.
  • Consider water-based coatings.
  • Buy only as much as you need.
Strippers and solvents – Do You?
  • Solvents can be expensive, treat them so and conserve them.
  • Consider less hazardous strippers when possible.
  • Reuse solvents and strippers (use dirty solvent to first loosen metal coating and then proceed with fresh; filter solvents to prolong life.)

When you must dispose of strippers and solvents: use a legitimate recycling facility or permitted hazardous waste treatment facility.

Water – Do You?
  • Reuse rinse water for metal working processes
  • Dry wipe or brush pieces before rinsing to prolong the life of your rinse water
  • Remember never to put waste water down a storm drain, sump or septic system. Inquire with your local water authority and follow their recommendations. This waste water could be put into a municipal treatment system.
Absorbents (sawdust, kitty litter and others) – Do You?
  • Remember that absorbents used to absorb hazardous materials will become hazardous and require special disposal.
  • Use drip trays and pans to prevent spills.
  • Use squeegees to recover product and cleanup spills
  • Use rags that can be “wrung” out to recover product.
Shop towels/rags – Do You?
  • Avoid disposable shop rags and use a shop towel recycling service
  • Wring out shop towels to reclaim solvents and other products (use proper personal protection e.g., gloves).
  • Avoid chemicals which may hinder laundering of shop towels (e.g., perchloroethylene and toluene).
  • Keep clean and dirty shop towels separate and well-labeled containers.
Aerosol cans – Do You?
  • Return defective cans to supplier; do not throw away.
  • Use refillable spray canisters for cutting fluids.
  • Remember that only totally empty cans may be landfilled.

Metal Waste

Scraps – Do You?
  • Efficiently cut and use metal to get the most from each piece.
  • Reuse scraps for future projects.
Metal dust and shavings – Do You?
  • Always wear personal protective clothing and respirator when when working around metal dust
  • Collect shavings/dust and store in a bucket. (Check with metal recycler for possible recycling.)
  • Try to keep metal shavings out of sump and drains.
Containers and Packaging of Metal Working Supplies – Do You?
  • Return empty containers to the distributor for re-use when possible
  • Train students to scrape paint containers clean so they are lawfully “empty”.
  • Reuse and recycle paper and cardboard as recommended under General Housekeeping.
  • Buy products with as little packaging as possible.
  • Separate reusable and recyclable packaging materials from those that can only be disposed of.

Adhere to all WATER QUALITY, AIR QUALITY and ENERGY CONSERVATION recommendations listed in General Housekeeping.