According to a fact sheet from the (ADEM) Alabama Department of Environmental
Management's Pollution Prevention Unit, the keys to pollution prevention in the
printing industry are
- material substitution,
- ink recycling and
- minimization of changeover.
With that in mind, ADEM offers printers these suggestions for minimizing the
pollution their facilities generate.
- Segregate spent fix baths from rinse waters and developer solutions.
- Silver recovery is more efficient on the more concentrated spent fix waste stream.
- Optimize bath life and reduce wastewater quantity by adjusting chemical
replenishment rates and washwater flow rates on photoprocessors.
- Keep lids on bulk solutions to prevent oxidation and contamination while in storage.
- Use materials on a first in, first out basis so as to not exceed shelf life
and thus reduce waste. Do not get rid of expired products by discharging to the wastewater treatment system.
- Purchase ink from distributors that will take back unused or spent ink.
- Special nondrying aerosol materials can be sprayed on ink fountains to keep them from drying out overnight. Fewer ink fountain cleanings will be required.
- Purchase new developing machines that use less rinse water and have
squeegees or air blades to reduce dragout from chemical baths to rinse water.
- Add acetic acid to the fix bath. This keeps the pH low, maximizing soluble complexes and extending bath life.
- Recycle inks to make black inks, or filter out inks instead of discharging
to the sewer.
- Change from alcohol-based to water-based inks and aqueous-type cleaning
- Save rinse water and transfer to an ink-splitting device that absorbs the
various ink pigments on a cellulose-based, porous material. Then, depending on state and local regulations, the nearly clear filtrate may be permitted to flow to the sanitary sewer, while the pigment-colored cellulose may be sent along with other wastes to the local landfill.
Benefits of water-based inks and cleaning agents
- They reduce solvent emissions by 80 percent or more.
- They reduce toxicity of liquid and gaseous wastes by approximately 90
- Wastes that were previously classified as hazardous can be recycled or
disposed of as nonhazardous, thus saving disposal costs.
- There is no difference in raw material costs for inks and cleaners,
productivity may increase, no capital expenditures are required, insurance
costs may decrease and nondisposable wiping materials provide a savings.
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