Bailey Motors and Panel Works Pty Ltd operates a panel repair workshop in Melbourne's inner city suburbs. Activities include panel repair, paint stripping, and respraying of repairs.
The existing process generated significant quantities of solvent and paint waste from spraying operations. The paint colour 'Recipe Book' used by Bailey Motors specifies the quantities of different base colours required to make up any colour. By following the recipe, the minimum amount of paint that could be made up was 250 mL, regardless of whether less than this was required for a particular job. In addition, waste solvent was also generated from cleaning of equipment.
Three different grades of solvent were used:
- a 'Grade A' thinner for viscosity adjustment of top coat paints;
- a 'Midway' thinner for viscosity adjustment of primers and undercoats; and
- a 'Gunwash' thinner for equipment cleanup.
Each of these solvents was purchased new, used and then disposed of by a specialist waste disposal company using incineration. The disposal cost was $80 per 60 litres.
Cleaner Production Initiative
The company purchased a small solvent recovery unit, which recovers solvent from the surplus paints left over from spraying operations. The unit consists of a boiler pot, combined with a water cooled condenser to recover clean solvent. As the recovered solvent was a mixture of 'Grade A' and 'Midway' thinners, it could not be used for viscosity adjustment in either top coats or undercoats and primers. It could, however, be used for equipment cleanup.
The Recylene-R2 recovery unit is a batch unit with a capacity of approximately 20 litres. A dried solid residue, principally containing paint pigments, remains at the end of the distillation cycle. This material is then removed, bagged and disposed of with the general rubbish. The recovery unit was purchased for approximately $6,000.
Advantages of the Process
The advantage of this initiative was that it eliminated the need to purchase new 'Gunwash' solvent for equipment cleanup. More 'Gunwash' quality solvent was being recovered from the panel shop operations than could be used for equipment cleanup, so the excess was sold to other panel shops for $40 per 60 litre drum.
The initial cost savings were significant, with elimination of waste disposal charges for waste solvent/paint, savings of $70 per 100 litres for gunwash solvent and additional income from the sale of reclaimed solvent to other panel shops. Since that time the economic savings have fallen due to the reduction in purchase price of new gunwash solvents and the uptake of the reclaiming technology by other panel shops. This has reduced the sales of reclaimed solvent by Bailey Motors. An excess of reclaimed solvents is now being generated, which is currently being stored on-site.