Conservation of Water Resources
Water is an important resource of the Earth, deeply connected to the abundance of land, sea and biodiversity. Water is essential to Mitsui Kinzoku Group's manufacturing processes. We are committed to the proper use of water in all aspects of our business operations, in dialogue with local communities to conserve water resources.
We also consider it important that all employees have access to safe drinking water and a sanitary water environment, and we have installed sanitary facilities and are working to raise awareness of water conservation at all of our sites.
Integrated Report - Initiatives for environmental issues［PDF 1.9MB］
Improve water efficiency
At our manufacturing sites, we monitor water use, wastewater discharge, and reuse/recycling volumes to ensure efficient water use.
Our nonferrous smelting and refining operation, which is a mainstay business of Mitsui Kinzoku Group, makes extensive use of water for cooling refining facilities and for cleaning raw materials, products, and equipment. This business accounts for more than 90% of the Group’s total water withdrawal. In using water, we strive to improve water use efficiency and conserve water resources, taking local conditions into account. Miike Smelting Co., Ltd. uses some of the wastewater discharged and treated by other Mitsui Kinzoku Group plants adjacent to the smelter, as well as rainwater. Kamioka Mining & Smelting Co., Ltd. uses freshwater with relatively high turbidity, such as mine water from the mining area after treatment. The smelting sites located on the waterfront use seawater in the cooling process.
We are also promoting the reuse and recycling of water both between processes and within processes by identifying the requirements of each of the refining processes in terms of water quality and quantity. For example, water that has been used in a process which requires high purity is reused in other processes that require only relatively low purity, and water used once is treated and circulated for reuse in the same process.
Reduction of Water Pollutants
Each manufacturing site monitors the status of its wastewater, including BOD and COD, which indicate the amount of organic matter in the wastewater, under stricter voluntary standards to ensure compliance with laws, regulations and ordinances. At our smelting sites, we manage wastewater with regard to the concentration of heavy metals and other pollutants, not only according to laws and regulations, but also in compliance with even stricter agreements with authorities and local community groups.
We have several wastewater monitoring stations along the wastewater routes, including wastewater treatment units, confluence points, and discharge outlets, which are constantly monitored by our ICT system for any anomalies. Mitsui Kinzoku Group also collects and manages the monitoring results from each site on a group-wide basis as well as shares emission reduction efforts and technologies.
Assessment and response to water risk situations
We use World Resources Institute (WRI)’s AQUEDUCT Water Risk Atlas to assess water risks at our manufacturing sites in Japan and overseas, mainly in terms of water stress and flood hazards.
Some of our sites in countries such as India, China, Indonesia, and Thailand were assessed as having Extremely High (>80%) or High (40–80%) levels of water stress. These sites mainly manufacture automotive components, and in FY2024 their freshwater withdrawal amounted to 160 thousand m³, representing 0.5% of the Group’s total. At each site, we are working to improve water efficiency by reducing water intake and introducing water recycling facilities.
Some coastal sites in Asia, such as Thailand, Malaysia, and China, and sites in the Miike area of Kyushu (Omuta City, Fukuoka Prefecture), face flooding risks from heavy rainfall. We are improving and reinforcing drainage channels, raising the height of flood-prone machinery, and introducing ICT systems for faster information transmission. At smelting sites, we are enhancing reservoirs and increasing wastewater treatment capacity to prevent the leakage of wastewater containing heavy metals and other pollutants during heavy rainfall or flooding. An automatic shut-off system for wastewater has also been installed for emergencies such as leaks.
We will continue to monitor the situation, conserve water resources, and minimize the impact on our operations and neighboring areas.
Initiatives in Water-stressed Areas (MKCI Sanand Plant)
MKCI's Sanand plant is located in the state of Gujarat in western India and produces exhaust gas purification catalysts for two-wheelers and four-wheelers. The area is rated Extremely High in WRI's Water Stress Assessment and there are seasonal restrictions on water withdrawal from the industrial park.
The plant requires pure water for its production activities. Until now, water has been taken from the industrial park and the wastewater has been treated in industrial wastewater processing equipment and then percolated underground in accordance with local laws. In order to recycle this treated water, we introduced purification treatment equipment that purifies the water using reverse osmosis membranes starting in 2022. This equipment removes impurities from the wastewater, and the treated water is used in the pure water production system to ensure water of the same level of purity as before. By using this water for production activities, it is expected to be possible to reduce the amount of water withdrawal. In addition, even in the event of water withdrawal restrictions from the industrial park, purified water can be provided and production will not be disrupted, allowing for smooth business operations.
When this treatment equipment is in full-scale operation, we expect to reduce water withdrawal by approximately 6,000 m3/year. Currently in trial operation, we will work to stabilize the quality of treated water and improve treatment capacity.