The Current Waste Profile for the Paint Process
There are a number of substances emitted during the motor vehicle painting process that are listed on the National Pollutant Inventory (NPI). These substances include air emissions, liquid and solid wastes from the process. Air emissions are found in the organic solvents usually used as paint carriers. These solvents are also used during cleaning processes when the spraying equipment has to be cleaned while changing colors. The most common ingredients in these solvents are xylenes and butanol. Other ingredients include butyl acetate and other mixed acetates in lesser amounts. Present hydrocarbons that are listed on the NPI include toluene, methyl ethyl ketone (MEK), styrene, and acetic acid. Solid and liquid wastes come from paint pigments that contain metals and metal oxides that are listed on the NPI. Other Recurrent Hazardous Waste are alkaline/acid cleaning solutions, used antifreeze and chemical paint stripper (methylene chloride).
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Substitutions to Use in the Painting Process
Proposed environmentally friendly substitutes in the vehicle painting process include adoption of the water borne paint technique similar to the one introduced by the Volkswagen Group. This technique, known as the Bell Bell process, seeks to make the painting process 100% electrostatic. The process reduces air emissions and requires less compressed air hence saves more energy at the same time. The second measure is to reduce the storage time of Recurrent Hazardous Waste in relation to the amount of emitted waste.
The New Waste Profile (30% Waste Reduction)
The painting process becomes much softer and over-spraying is reduced significantly. The Bell Bell process reduces paint usage by as much as 50% and hence fewer chemicals are used at the wash-out area and lesser hazardous wastes are emitted. Emission of volatile organic compounds is lowered by approximately 30%.