Substituting Less Toxic Solvents for Hazardous Solvents

1. Thilmany substituted a non-toxic, non-hazardous solvent for mineral spirits in all of the maintenance parts washers. The parts washers also were refitted with a dual filter system so that the recirculated solvent could be continuously cleaned. The used filters have been tested and found to be non-hazardous.
2. A less toxic, non-chlorinated solvent is being used instead of perchloroethylene/n-butanol in their flexographic platemaking process. This solvent is then shipped for recycling.
3. The company also developed new techniques to gather basis weight information so that only a small percentage of the samples taken must be tested with trichloroethylene.

1. mineral spirits
2. perchloroethylene/n-butanol
3. trichloroethylene

Waste

1. mineral spirits contaminated with grease
2. perchloroethylene contaminated with bits of rubber
3. trichloroethylene contaminated with polyethylene coating residue

Disposal

1. shipped off-site for hazardous waste disposal
2. shipped off-site for hazardous waste recycling
3. shipped off-site for hazardous waste disposal

Pollution Prevention Approach
Feedstock

1. ZEP 143 light aliphatic naphtha solvent; not listed as RCRA hazardous waste
2. SOLVIT plate wash; petroleum hydrocarbon with aliphatic alcohol; less toxic, non-chlorinated
3. process modification

Waste

1. used filters; no liquid
2. contaminated, less toxic solvent
3. spent trichloroethylene

Disposal

1. closed-loop reuse; filters disposed as solid waste
2. shipped off-site for recycling
3. reduced amount for disposal

1. $375 for initial washer/filter
2. none
3. none

Operating/Maintenance Cost

1. $280 replacement filters/year. Raw material cost went up while disposal costs decreased, resulting in $600 annual savings.
2. Retrofitting of processing unit, one-time costs minimal. Waste continues to be sent out for reclamation, but is now solid waste, not hazardous.
3. At 1990 costs, Thilmany now saves $30,000/yr in raw material and disposal costs. At 1992 costs, Thilmany would save $59,000/yr.

Payback Period

1. less than 2 months
2. not available
3. immediate

• The conversion from perchloroethylene/n-butanol to a non-chlorinated solvent in their flexographic platemaking process forced Thilmany to modify the ventilation system previously used in that process.
• Employees needed retraining in order to become familiar with the new products.
• Replacements for the hazardous substances were difficult to find. Thilmany was concerned that the product quality remain the same; therefore, staff had to evaluate several product substitutes before adequate substitutes were found.

Pollution Prevention Information Clearinghouse
Wisconsin Department of Natural Resources
Hazardous Waste Minimization Program
608/264-8852, 608/267-9523 or 608/267-3763