CWTC is located in the Kaohsiung Nanzih Technology Industrial Park. Our water comes entirely from the Taiwan Water Corporation; therefore, water sources are not affected. In view of the limited water resources in Taiwan, we have gradually installed recycling systems with membrane filtration process at our Taiwan site since 2021 to increase our water recycling rate and lower tap water consumption. These systems also mitigate water risk during the dry and drought seasons.
Our overseas plants are located in industrial parks where water comes from local water companies. In line with our water saving and recycling policy, the Suzhou plant has installed a water reclamation system ahead of others to recycle and reuse process water above a certain quality level. The system is mainly for cleaning and electroplating processes where a large volume of water is required. The recycling and treating of secondary water bring our internal water cycle to a certain standard, thereby reducing raw water supply and achieving the goal of a significant reduction in water consumption. In view of the water-saving benefits in our Suzhou plant, other plants have started to schedule the installation of water reclamation systems.
Water stewardship CWTC uses tap water mostly for wet processing (electroplating), cleaning and environmental protection. Water consumption by site for 2022 is shown in the table below. In the face of global climate changes in recent years, we continue to monitor our water consumption and proactively promote plant-wide water-saving measures to ensure there is no immediate water scarcity issue arising from a lack of water resources. Furthermore, our Taiwan plants have started to install systems for process water recycling since 2021. The systems treat and filter rinsing water with high acid concentration for reuse instead of releasing it directly from the wastewater treatment plant as was our previous practice, thereby increasing the reuse rate of process wastewater. There are also other water-saving measures in place to lower our water consumption.
Water conservation measures within the plants ²Water Reclamation System - recycling and reuse of process water To cherish the water resources, all sites have gradually adopted the “water reclamation system” to recycle and reuse process water above a certain quality level. The system is mainly for cleaning and electroplating processes where a large volume of water is required. The recycling and treating of secondary water bring our internal water cycle to a certain standard, thereby reducing raw water supply and achieving the goal of a significant reduction in water consumption.
In 2021, the Taiwan plants installed recycling systems where process water is recycled for reuse through ultrafiltration (UF) and reverse osmosis (RO) processes. In 2022, we adopted membrane bioreactors (MBR) devices to replace the UF system. The enlarged membrane pore size increased fluxes and improved the fouling problem, thereby enhancing the efficiency of the water recycling system. At the same time, the switch reduced the frequency of backflushing and chemical cleaning and consequently the consumption of recycled water. In addition, the replacement of filter bags at a lower frequency was equivalent to waste reductions. In 2022, the combination of MBR and RO processes increased the average daily volume of recycled water to the industrial tanks by 200 metric tons, lifting the water recycling rate by 5.1% compared to 2021.
We plan to install a second set of MBR system in 2023 and expect to have an additional 100 metric tons of recycled water every day.
²Pure Water Recycling System - recycling and reuse of pure water
Water derived by putting the concentrate water from RO systems through RRO system is used in our manufacturing process. Treatment by the 2B3T process in RO system allows the quality of concentrate water from RRO system to be superior than the tap water. Therefore, the water is recycled for reuse through the industrial tanks. In 2022, our pure water recycling system recovered 66,767 metric tons of water within our Taiwan plants, accounting for 13% of the total water volume.
²Water-saving design of machinery and equipment
Electroplating equipment adopts the counter-current rinsing design where the rinse water is circulated through three washing tanks, achieving water conservation.
Effluents and water quality monitoring and control
Effluents from our Taiwan, China and overseas sites amounted to 379,000 metric tons, 474,000 metric tons and 265,000 metric tons in 2022, and 370,000 metric tons, 527,000 metric tons and 266,000 metric tons in 2021, respectively. Effluents of each site was treated before being discharged.
CWTC regularly performs sampling and data review concerning effluents every year to ensure wastewater from the process fully complies with the current environmental laws and regulations and the management standards of the industrial park, so as to reduce the impact of pollution on the environment. The test results of effluents in 2022 are summarized in the table below. Since we proactively review and improve the wastewater pollution control systems in our plants, the quality of effluent discharged is currently in compliance with the standards set out in local laws and regulations.