Metal finishing facilities generate various types of air emissions, process wastewater, and solid and hazardous chemical waste. Figure 3 describes the pollution emissions that can occur during metal surface preparation and finishing operations at plating shops.

As Figure 3 shows, certain toxic inputs may appear as outputs in emissions to several types of environmental media. For example, the use of halogenated solvent cleaners to prepare a metal surface for finishing may generate air emissions as well as hazardous waste.

In general, process wastewater is the most costly emissions control problem facing a plating shop. As Figure 4 shows, plating shops spend, on average, 62% of their total environmental compliance budget on addressing wastewater contamination issues.

Figure 4

The contaminants in a plating shop's wastewater come from process bath dumps (siscarded process or cleaning bath that contains trace metals, organics, and reacted and unreacted materials from tank bottoms), solution drag-out (the quantity of bath solution carried on the workpiece as it moves from one processing step to another) which contaminates rinse water.

Sectors - Metal Finishing