&EPA United States Environmental Protection Agency Risk Reduction Engineering Laboratory Cincinnati, OH 45268 Research and Development EPA/600/M-91 /047 Oct. 1991 ENVIRONMENTAL RESEARCH BRIEF Waste Minimization Assessment for a Manufacturer of Printed Labels F. William Kirsch and J. Clifford Maginn* Abstract The U.S. Environmental Protection Agency (EPA) has funded a pilot project to assist small- and medium-size manufacturers who want to minimize their generation of hazardous waste but lack the expertise to do so. Waste Minimization Assessment Centers (WMACs) were established at selected universities and procedures were adapted from the EPA Waste Minimiza- tion Opportunity Assessment Afenua/(EPA/625/7-88/003, July 1988). The WMAC team at the University of Tennessee per- formed an assessment at a plant producing printed labels — approximately 14 billion labels/yr. Steel printing cylinders are nickel and copper plated, etched with the label patterns to be printed, chromium plated, and then used with ink applied to print the labels. About 75% of the cylinders are chemically etched, and the remainder are mechanically etched. Solvents used with ink concentrate and for cleaning press parts are recoverad and sold to reclaimers. Spent reagents, filters, cleaning rags, and sludge are shipped offsite for disposal. Process wastewater and rinse water are treated by ion exchange and distillation. The team's report, detailing findings and recommendations, indicated that most waste other than water and paper consists of spent solvents, and that the greatest savings could be obtained by using recovered solvent instead of virgin solvents for cleaning at press side. 'University City Science Center, Philadelphia, PA 19104. This Research Brief was developed by the principal investiga- tors and EPA's Risk Reduction Engineering Laboratory, Cincin- nati, OH, to announce key findings of an ongoing research project that is fully documented in a separate report of the same title available from the authors. Introduction The amount of hazardous waste generated by industrial plants has become an increasingly costly problem for manufacturers and an additional stress on the environment. One solution to the problem of hazardous waste is to reduce or eliminate the waste at its source. University City Science Center (Philadelphia, PA) has begun a pilot project to assist small- and medium-size manufacturers who want to minimize their formation of hazardous waste but lack the inhouse expertise to do so. Under agreement with EPA's Risk Reduction Engineering Laboratory, the Science Center has established three WMACs. This assessment was done by engineering faculty and students at the University of Tennessee's (Knoxville) WMAC. The assessmentteams have considerable direct experience with process operations in manufacturing plants and also have the knowledge and skills needed to minimize hazardous waste generation. The waste minimization assessments are done for small- and medium-size manufacturers at no out-of-pocket cost to the client. To qualify for the assessment, each client must fall within Standard Industrial Classification Code 20-39, have gross {gy Printed on Recycled Paper ------- annual sales not exceeding $50 million, employ no more than 500 persons, and lackinhouse expertise in waste minimization. The potential benefits of the pilot project include minimization of the amount of waste generated by manufacturers, reduced waste treatment and disposal costs for participating plants, valuable experience for graduate and undergraduate students who participate in the program, and a cleaner environment without more regulations and higher costs for manufacturers. Methodology of Assessments The waste minimization assessments require several site visits to each client served. In general, the WMACs follow the procedures outlined in the EPA Waste Minimization Opportu- nity Assessment Manual(EPA/625/7-88/003, July 1988). The WMAC staff locates the sources of hazardous waste in the plant and identifies the current disposal or treatment methods and their associated costs. They then identify and analyze a variety of ways to reduce or eliminate the waste. Specific measures to achieve that goal are recommended and the essential support- ing technological and economic information is developed. Finally, a confidential report that details the WMAC's findings and recommendations (including cost savings, implementation costs, and payback times) is prepared for each client. Plant Background The plant produces printed labels. It operates 6,120 hr/yr to print approximately 14 billion labels. Manufacturing Process This plant prints label patterns on wide paper roll stock. About 80% of the labels are rolled onto cardboard cores, which are slit Into narrow rolls. The remainder are cut into sheets, which are counted into stacks. Raw materials include reagents for nickel-, copper-, and chromium-plating and etching of print- ing cylinders, light-sensitive film, blue dye, printing ink con- centrates, solvents, fitter media, cleaning rags, cotton, and paper stock. Plating and etching of the steel printing cylinders used to print the labels involve the following steps: • The cylinders are degreased and washed. (Used cylinders are first dechromed in an acid bath containing a dechrome salt and then machined to remove previously etched label patterns). • The cylinders are nickel plated in a tank containing a solution of nickel sulfate, nickel chloride, and boric acid. After rinsing, the cylinders are copper plated in a tank containing copper nuggets in a solution of sulf uric acid and a hardness additive. • After rinsing, the plated cylinders are polished with pumice and washed with detergent. • About 75% of the cylinders are chemically etched. Using pattern negatives, a base film is developed by a photo- graphic process. (Silver is recovered for sale.) After a photoresist coating is applied to the printing cylinders, the patterned film is applied and the cylinders are exposed to high-intensity light. A blue dye is then applied for develop- ment, and the photoresist and dye coatings are hardened in isopropyl alcohol. • The cylinders are etched in ferricchloride solution contain- ing copper sulf ate, and then rinsed in water. About 90% of the cylinders are sent to the printing process at this stage; the remaining 10% are chrome plated first in a solution of chromic acid and sulfuric acid. The following steps are carried out in printing the labels: • Ink concentrates are mixed with solvents for desired color and drying times and applied to the paper using an impres- sion type of press. • After each color is applied the ink is dried on the line in an electric or gas-fired oven. Up to 6 colors can be applied to the paper in one line. • After each run, press parts are cleaned using solvents and rags. • About 80% of the printed paper is slit into narrow rolls and packaged. The remainder is cut into sheets. Existing Waste Management Practices Solvent vapors from the printing-line drying ovens are recov- ered in three parallel carbon adsorption beds and regenerated with steam. The effluent steam is condensed producing a solvent layerthat is decanted, neutralized with hydrogen perox- ide and caustic soda, and sold to reclaimers. Sodium acetate produced in the neutralization is shipped offsite for disposal. Spent reagents, lathe waste, and spent dye are shipped offsite for disposal. Solvent-laden rags and cotton from cleaning press parts are also shipped offsite for disposal. Spent filters, scrap paper, and obsolete label patterns are discarded with municipal trash. Water from plant operations is treated in an ion exchange unit and discharged to public water facilities. Waste Minimization Opportunities The type of waste currently generated by the plant, the source of the waste, the quantity of the waste, and the annual waste management costs are given in Table 1. Table 2 shows the opportunities for waste minimization that the WMACteam recommended forthe plant. The type of waste, the minimization opportunity, the possible waste reduction and associated savings, and the implementation cost along with the paybacktime are given in the table. The quantities of hazardous waste currently generated by the plant and possible waste reduction depend on the production level of the plant. All values should be considered in that context. ft should be noted that, in most cases, the economic savings of the minimization opportunities result from the need for less raw material and from reduced present and future costs associated with waste treatment and disposal. Other savings not quantifi- able by this study include a wide variety of possible future costs related to changing emissions standards, liability, and em- ployee health. It should also be noted that the savings given for each opportunity reflect the savings achievable when imple- menting each waste minimization opportunity independently and do not reflect duplication of savings that would result when the opportunities are implemented in a package. Additional Recommendations In addition to the opportunities recommended by the WMAC team, two other measures were considered. These measures were not analyzed completely because of insufficient data or minimal savings as indicated below. They were brought to the ------- plant's attention, however, because these approaches to waste reduction may increase in attractiveness with changing plant conditions. • Water from the plant's solvent recovery system is sprayed into the firebox of an incineration boiler for disposal. An option to use this slightly contaminated water as boiler feedwater was not recommended because of a lack of information on the possible effect of the contained solvent on the heat transfer surface of the boiler and on the rest of the steam system. • Advance preparation of solvent-laden rags used to clean press parts would reduce the quantity of solvent lost by evaporation. This measure was not analyzed further be- cause minimal savings would be expected. This Research Brief summarizes a part of the work done under Cooperative Agreement No. CR-814903 by the University City Science Center underthe sponsorship of the U.S. Environmen- tal Protection Agency. The EPA Project Officer was Emma Lou George. Table 1. Summary of Current Waste Generation Waste Generated Source of Waste Annual Quantity Annual Waste Generated Management Cost Solvent vapors Drying oven exhaust. Solvent vapors in drying oven exhaust are adsorbed in carbon beds, desorbed by a steam purge, condensed, decanted from the steam condensate, and shipped to a reclaimer. 300,000 gal $1,028,869' Spent ink/solvent mixture Spent blue dye mixture Solvent vapors Spent reagent solutions (Sodium acetate, ferric chloride, hydrochloric acid, and chromium, nickel and copper salts) Spent rinse water Spent cotton, rags and polishing cloths Sludge from water treatment Paper waste Ink solids Lathe waste (turnings, pumice, copper fines) Condensed inks, mixed with blended solvents, are used in 34,540 gal printing. The spent mixtures are shipped offsite for disposal. Blue dye solution, used in preparing printing cylinders, is 1,100 gal recycled to the process. When spent, it is shipped offsite for disposal. Solvents used in etching and printing evaporate to the plant 189,055 gal atmosphere. Spent reagents from plating, etching, and solvent recovery 22,118 gal operations are shipped offsite for disposal. Rinse water from plating and etching operations, and fume 252,910 gal scrubber effluent, are passed through an ion exchange resin bed and discharged to POTW Solvent-laden cotton and rags from cleaning, and pigment- 1,760 gal2 laden polishing cloths, are shipped offsite for disposal. Sludge generated on regeneration of ion exchange resin used 2,090 gal for water treatment is shipped offsite for disposal. About 4,200,000 Ib/yr of scrap paper is sold. The remainder, 5,600,000 Ib 5,600,000 Ib/yr, is disposed of as landfill. Waste ink solids from printing operations are shipped offsite 1,650 gal to be burned as fuel. Waste from machining and polishing printing cylinders is 495 gal shipped offsite for disposal. 49,482 5,314 541,868' 35,388 5,000 12,800 5,700 39,600 13,500 900 Spent ink filters Used ink filters from printing operations are shipped offsite for disposal. 550 gaP 4,000 'Includes savings on raw materials. 232 ban-els of spent cotton, rags, and polishing cloths. 310 barrels of spent ink filters. •feV.S. GOVERNMENT POINTING OFFICE: 1991 - 548-028/40073 ------- Tabla 2. Summary of Recommended Waste Minimization Opportunities Waste Generated Annual Waste Reduction Net Implementation Payback Minimization Opportunity Quantity Percent Annual Savings Cost Years Spent Solvent Used recovered solvent instead of virgin solvent for cleaning press parts. None $284,294' $0 Spont safety solvent Ink/solvent mixture Safety solvent vapors Spont ink filters Used recovered solvent None - 59,443' instead of safety solvent for cleaning. Automate mixing of ink, 5,225 gal 75 47,085' extender, and solvent to reduce oyermixing and evaporative loss. Replace a cleaning tank 2,833 gal 50 9,604' lid to reduce solvent evaporation loss. Rinse spent ink filters 363 gal2 66 5,016' with solvent and reuse 288,800 500 6.1 0.1 'Includes savings on raw materials. =6.6 barrels per year of spent ink filters. United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 BULK RATE POSTAGE & FEES PAID EPA PERMIT NO. G-35 Official Business Penalty for Private Use $300 EPA/600/M-91/047 ------- |