From Wastewater to Ultra-pure Water: Assessing the Recycle Potential of Industrial Waste Discharges in the Semiconductor Industry

With increasing population and rising economic development competing for limited water supplies, the semiconductor manufacturers throughout the United States have been actively working to reduce their water usage. One conservation method with the potential to reduce water usage substantially is the recycling of manufacturing wastewater into the ultra-pure water (UPW) production process. Accounting for about 60% of the total UPW consumed, recycling of the spent rinse-waters alone would significantly decrease water usage. However, to avoid loss of income due to defective product, waste stream recycling into the UPW process must be planned and implemented very carefully. The objective of this research is to investigate the potential for such waste stream recycling at one industrial site, Motorola’s MOS-11 semiconductor plant, and to develop the methodology for rapid assessment of waste stream recycle potentials at other sites. Specifically, a categorized list of manufacturing processes that generate industrial wastewater was developed along with “ball park” wastewater quantity and quality information for each manufacturing tool. Then, waste streams were selected as potentially recyclable based on high volume and the absence of organic constituents. Currently, flow rate and water quality measurements are being done to reassess whether or not the selected waste streams are potentially recyclable. Preliminary results and conclusions about these selected waste streams as well as discussion of the issues involved in recycle potential assessment are presented here.