Ask the Expert Question-and-Answer Archive (Wastewater Treatment)

by Mike McGinness, EcoShield Environmental Systems, Inc.
November, 2002

Waste Stream Costs From Copper Electroplating

Q. We are currently trying to understand the cost to plate a stainless steel bar with a thick copper coating. Due the thickness (2.5mm) of the copper, we are predicting that our wastestream will be extremely expensive. Can you tell me if for budgetary estimating purposes it is appropriate to assume that the disposal of these materials will cost ~ $1.60 per ounce of plated material?

A. Why would it have any affect on the waste water treatment costs? Where did you get the $1.60 per ounce number?

Most waste water treatment costs are due to the rinsing, the costs of which vary with the surface area of the parts, the number of parts and the number of recycled rinses used before the final rinse. The thicker the plating per part, the less rinsing there will be per unit thickness of coating. Many plating operations are substituting well designed rinse water and plating bath recycling and recovery equipment (capital costs) for waste disposal costs. You may want to consider budgeting a lot more dollars for capital equipment (recycling) to reduce the waste treatment costs to a minimum.

In order to come up with a budgetary number you will need data on the actual parts, including the drag out rate of plating solution (which is affected by part shape, plating solution viscosity, metal concentration, surface tension and rinse recycling just to name a few parameters) and rinse water flow rate. Without this kind of data any guess is as good as another in my opinion, since they are all likely to be way off.

Let me know if I can be of further assistance.