P2 in the Chemical Industry
Crowe Industrial Coatings
Crowe Industrial Coatings (SIC 2851) reduced hazardous waste generation and TRI chemical generation by improving operating practices, training employees on waste reduction, and reducing the use of solvent-based products. As a result, raw material, waste management, and disposal costs have been reduced.
Crowe Industrial is a small paint manufacturing facility whose main product lines are specialty paints and industrial coatings. The facility has a waste policy and a hazardous waste reduction plan, and initiated its waste reduction efforts in 1990.
Crowe Industrial uses a batch process to mix raw materials into a variety of paint products. Raw materials used in the process include solvents, organic resins, pigments, and other inert materials. These materials are received in bags and drums. A milling process is applied to some batches for added pigment dispersion.
When a batch is finished, the paint is strained with a nylon or polyester mesh bag as it is loaded from the production tank into a shipment container. The tanks and processing equipment are cleaned between batches. A recycled mixture of ketones, alcohols, and aromatics is used for cleaning. Cotton mops and rags are used in general clean-up of equipment, bench tops, and the floor.
Waste is generated during clean-up activities. Washing tanks and other equipment produces a waste containing solvents, pigments, and organic resins. Typical solvents used include acetone, methyl ethyl ketone, methyl isobutyl ketone, mixed alcohols, toluene, and xylene. The cleaning activities and their corresponding percentage of the total wastestream are: tank washing (45%), mill flushing (22%), and general cleanup (33%). Other hazardous wastes include straining bags, rags, and mop heads contaminated with solvents. These items are wrung out to remove as much liquid as possible, and then disposed of as hazardous waste.
Source reduction activities investigated at the facility include production scheduling, batch consolidation, raw material substitution/alternative product design, automated tank washing, and improved operating and housekeeping practices. Automated tank washing has reduced the amount of solvent needed to clean a tank from 3 to 2 gallons. The replacement of some solvent based products with powder coatings has also helped reduce hazardous waste and TRI chemical generation.
Anticipation of future orders and manufacturing of excess product in larger batches would reduce cleaning; however, it would require carrying excess inventory and is not economically feasible. Non-hazardous cleaning agents were investigated, but they did not clean the equipment well enough. While further reductions are proving difficult, Crowe Industrial continues to seek opportunities through better general housekeeping and operating procedures, and training of employees in waste reduction opportunities.
Crowe Industrial has reduced hazardous waste generation from 149,100 pounds in 1990 to 75,460 pounds in 1995. In addition, TRI chemical generation has been reduced from 91,710 pounds in 1991 to 29,301 pounds in 1995. Reductions can primarily be attributed to improving operating practices and training employees to reduce waste. The reduction of hazardous waste generation has saved about $10,000 in disposal costs, $29,000 in raw materials, and $18,000 in waste management costs annually.