With increasing capacity and research investment, TSMC adheres to the waste management principle of "Minimizing Waste and Maximizing Resource". In 2015, sulfuric acid waste and ammonia nitrogen wastewater were successfully combined into ammonium sulfate wastewater, which was outsourced and used for other purposes. TSMC led the industry to introduce the Mechanical Vapor Recompression (MVR) technology to convert ammonium sulfate wastewater into valuable industrial-grade ammonium sulfate products. After introducing the technology for a year, as of November of 2019, the outsourced sulfuric acid waste and ammonium sulfate wastewater decreased by about 94,000 tons and 1,200 tons, respectively. This created an economic value of NT$140 million per year (including reducing outsourced disposal fees and sales fees for recycled resources), moving towards the sustainable development goal of waste reduction.
Fulfill Circular Economy by Recycling Sulfuric Acid Waste and Ammonium Nitrogen Wastewater
In 2015, TSMC developed a pre-processing system for sulfuric acid waste and ammonia nitrogen wastewater. Recycled sulfuric acid was used as adsorbent and was combined with ammonia nitrogen wastewater for creating ammonium sulfate wastewater, which outsourced for other purposes. This action not only achieves the emission regulation of ammonia nitrogen wastewater but also effectively reduces the outsourcing of sulfuric acid waste.
Milestones of TSMC’s Recycling on Sulfuric Acid and Ammonium Nitrogen Wastewater
In 2018, TSMC led the industry to introduce the MVR technology and used Fab 15A as a starting point to convert ammonium sulfate into valuable industrial-grade ammonium sulfate products for resale to fulfill a circular economy. In 2019, the output of ammonium sulfate surpassed 200 tons. Ammonium sulfate wastewater is going to be completely transformed into industrial products in 2022 as MVR is adopted in all other fabs (including fabs that will complete construction and start production before 2022). This will achieve a milestone of zero outsourcing of ammonium sulphate wastewater.
Combining Used Sulfuric Acid Waste with Ammonia Nitrogen Wastewater into a Valuable and Reusable Resource
Purification Technology of Electronic-Grade Materials Under Development; Resources Back into Process
Besides enhancing the recycling of ammonium sulfate wastewater, TSMC develops the purification technology of electronic-grade materials, planning to refine ammonia gas from ammonium sulfate products, then compress and vaporize into an electronic-grade raw material. In this way, ammonium sulfate becomes a high-value product, which can be reused in the process of wafer manufacturing, to achieve the sustainable development goal of recycling and circular economy.