In response to the United Nations Sustainable Development Goal (SDG) No. 6—Clean Water and Sanitation, TSMC is committed to implementing sustainable water resource management. To address the conductivity of discharged wastewater and reduce the use of chemical reagents, TSMC developed the "Ammonia Nitrogen Wastewater Diversion and Processing Inspection System" in 2024. This system operates through a three-stage process—"Precise Diversion, Inspection Management, and Resource Regeneration." Low-concentration ammonia wastewater is channeled to biological treatment systems, where ammonia nitrogen is repurposed as a nitrogen source for microorganisms. High-concentration Ammonia wastewater undergoes treatment via a degassing membrane process, converting ammonia nitrogen into ammonium sulfate, thereby realizing resource regeneration. In June 2025, the system was successfully implemented at Fab 20 Phase 1, yielding remarkable results: a 40% reduction in discharged wastewater conductivity and a 30% decrease in chemical reagent usage. These advancements are projected to lower carbon emissions by 8,950 tons annually and generate green benefits valued at NT$102 million, setting a new standard in wastewater resource management.

Three-Stage Innovation: Advancing Environmental Protection and Operational Efficiency

Previously, TSMC treated ammonia nitrogen wastewater of varying concentrations by mixing it together for unified processing. However,  this approach required reverse osmosis technology to concentrate the ammonia nitrogen in low-concentrated mixed wastewater before applying degassing membrane to enhance removal efficiency. This process demanded additional chemical reagents and incurred higher operational costs for equipment. To enhance environmental sustainability and reduce reagent usage, TSMC’s WET clean and Facility teams jointly developed the innovative "Ammonia Nitrogen Wastewater Diversion and Processing Inspection System." 

Stage one: Through analyzing the wastewater discharge behavior of process tools, the team established gradient-based diversion rules and created a database. This enabled precise identification of ammonia nitrogen wastewater with varying concentrations. 

Stage two: The team devised an internal pipeline inspection method for tools, completing diversion inspections for approximately 1,000 tools and a total of 5,887 drain ports during the first phase of Fab 20. This effort was accompanied by optimization of wastewater routing and software configurations, ensuring the safe transport of different types of wastewater to appropriate treatment systems while improving overall management efficiency.

With improvements achieved during the first two stages, the ammonia nitrogen concentration in wastewater was doubled without requiring reverse osmosis processing. This innovation effectively reduced the use of chemical reagents, minimized waste generation, and saved energy. In Stage Three, the team conducted rigorous testing to determine the optimal balance among ammonia nitrogen concentration, water volume, ammonium sulfate concentration, and discharged ammonia nitrogen concentration. Wastewater of different concentrations was then routed to biological treatment systems and degassing membranes, transforming it into microbial nutrients and ammonium sulfate, respectively, thereby creating new value in resource recycling.

Developing prevention and treatment technologies is a key strategy in TSMC's water resource management efforts. The Ammonia Nitrogen Wastewater Diversion and Processing Inspection System has now been integrated into the standard design for future fab construction. The system is being progressively implemented in fabs with utilizing processes below N7, further enhancing wastewater treatment efficiency. In addition, TSMC is actively exploring the feasibility of converting low-concentration fluoride-containing wastewater into high-purity cryolite, leveraging innovative technologies to advance resource recycling and realize its vision for sustainable water management.