| Contents Notes |
The study summarized here evaluated, on a technical and economic basis, the effect of substituting water-based inks for solvent-based inks in a flexographic printing process. To reduce volatile organic compound (VOC) emissions by switching from the use of solvent-based inks to water-based inks, several equipment modifications and a feedstock substitution were completed: dryer capacity enhancement, press roller modification, ink handling equipment upgrade and installation of an in-line corona treatment system. Water-based inks containing 72.5% less VOC were used in lieu of, and in conjunction with, traditional solvent-based inks. The ink substitution reduced the emissions generated from the printing process. For each percent increase in water-based ink use, VOC emissions were reduced 14 lb. This was based on usage of about 2250 lb of solvent-based ink/wk, which caused a VOC emission of about 1570 lb. Typically, the substitution did not adversely affect product quality or non-hazardous scrap waste generation. The average reduction of 95% of liquid F003 waste from waste ink and cleaning solvents recorded during the study period resulted from operational practice changes and employee training. To complete the economic evaluation, the costs of press modifications, ancillary equipment, waste disposal, inks, and solvent were obtained. A payback period and project net present value were calculated. The project has a positive net present value of $39,165 and a payback period of 2.5 yr, based on 21% utilization of water-based ink. If full conversion to water-based inks is implemented, the payback period is theoretically reduced to 0.54 yr. Additional benefits from reduced VOC emissions and liquid hazardous waste have been an improved working environment: reduced indoor air pollutants, reduced handling of hazardous solvents by employees, and the appreciation by company employees of the need to make a conscious effort to further reduce waste generation. |
