Effective Use of Water Resources

Approach to Water Resources

In line with the Kioxia Group’s Environmental Policy, we continually strive to reduce the environmental impact of the wastewater produced during our manufacturing processes. We recycle the water we use in accordance with our own standards, which are stricter than current legal requirements, in order to conserve precious water resources and ensure business continuity.

Amid worldwide concern over water shortages, Kioxia Group has established the conservation of water resources and the ensuring of stable operations as business priorities. The balance between supply and demand, the amount of water that can be withdrawn, and the quality of water vary greatly between regions. Accordingly, Kioxia Group has identified water-related risks for each region, focusing not only on the short term but on the medium- to long-term as well, and conducts environmental impact assessments from all angles to ensure appropriate use of water resources. In doing this, we also consider the impact of external environmental factors, such as drought and flooding, on our business operations, as well as the impact of our operations on local water levels. 

Water Management Structure

At Kioxia Group, we prioritize all water-related initiatives and indices, seeing these as a key factor in the Group’s medium- to long-term growth, and we call these priority areas “sustainability materiality.”

Sustainability strategies and policies, including those related to water, are formulated at Sustainability Strategy Meetings, chaired by the President and CEO, with the degree of target achievement confirmed in each case, before a final review by the Board of Directors.

Key performance indicators (KPIs) are discussed and determined by a Sustainability Committee chaired by the executive officer in charge of sustainability, based on sustainability strategies and policies formulated in Sustainability Strategy Meetings, including those related to water.

At Environmental Management Review Meetings, which involve discussions primarily between the officer responsible for environmental protection, the impact on our business, compliance with relevant laws and regulations, and achievement of our KPIs are all reviewed, with reference to social and legislative trends, and our medium-term environmental plan is evaluated in consideration of the risks and opportunities related to our usage of water.

Issues deliberated at these meetings include the installation of equipment to reduce water consumption during the construction of new plants, and the management of risk through business continuity management (BCM) activities. Assessments of water hazards such as overflowing rivers, large-scale typhoons and drought are also conducted as part of our BCM policy to reinforce our overall business risk management and enable swift business continuity in the wake of any disaster. Furthermore, specialists investigate and monitor domestic and international regulations and trends to reduce the risks posed to constantly changing water environments.

Evaluating Water Risk

The balance between supply and demand, the amount of water that can be withdrawn, and the quality of water all vary greatly between regions. Kioxia Group has commissioned external experts to evaluate water-related risks from the perspective of current and future water supply and demand risks; these are assessed using tools such as the World Resources Institute's WRI Aqueduct and the Water Risk Filter. We use these assessments to analyze risks such as water stress levels and seasonal variations in water supplies through the year 2040 in order to understand the potential impact on our business activities.

The outcome of the assessment of our Group’s manufacturing plants was confirmation that they are not exposed to any water risk likely to have practical financial or strategic impact prior to the year 2040. This assessment was based on investigations into such areas as water supply and demand risks (driven by seasonal changes, the frequency of droughts, water storage capacity and water source protection levels), the risk of water-related disasters such as flooding or landslides, and regional vulnerability to water pollution that might endanger public health or ecosystems.

Water-related Targets and Results

Using FY2017 levels as the baseline, Kioxia Group has set targets for the reduction of our water intake per storage capacity output, and we manage these using a PDCA cycle.

For FY2022, we set the target of consuming 50.9% or less of FY2017 levels, and achieved this with an actual result of 42.1%.

Going forward, we will continue to promote activities aimed at achieving water intake reduction targets by both reducing water consumption and by promoting recycling.

Enhanced Wastewater Monitoring

Manufacturing sites of Kioxia Group in Japan monitor wastewater using voluntary standards that are more stringent than the prevailing legal requirements, in order to minimize the impact of our business operations on the atmosphere and on rivers.

Around-the-clock, automated monitoring is conducted in respect of legally regulated factors, including chemical oxygen demand (COD), suspended solids (SS), fluorine (F), and hydrogen ion (pH) levels. Kioxia Group in Japan also voluntarily controls items not subject to legal restrictions through sampling conducted at the Analysis Centers located within our manufacturing plants. Kioxia Corporation’s Yokkaichi Plant tests around 37,000 samples of wastewater each year, with Kioxia Iwate Corporation testing around 15,000.

As during the previous fiscal year, Kioxia Group was not subject to any government fines or penalties related to wastewater in FY2022.

BOD (Biochemical Oxygen Demand) concentration control values in drainage to rivers
(Kioxia Corporation’s Yokkaichi Plant)

Law: ≦120mg/L, Mie Prefecture Ordinance: ≦20mg/L, Yokkaichi City Pollution Prevention Agreement: ≦4.5mg/L, Voluntary Control Value: ≦4.0mg/L, Actual Result in FY2022: 0.8mg/L.

Water Recycling

In order to promote more effective use of resources, Kioxia Group in Japan is devising initiatives aimed at controlling the amount of water we intake and discharge at our manufacturing plants. One example of this is the collection and reuse of water used in manufacturing processes inside plants.

Water recycling at manufacturing sites Kioxia Group in Japan in FY2022 resulted in the collection and reuse of approximately 33 million ㎥ of water (equivalent to about 57% of our total intake), which has helped ensure the effective use of water resources and reduced the environmental impact of public water utilities’ operations.

Effective use of rainwater

Solid State Storage Technology Corporation (SSSTC) in Taiwan makes effective use of rainwater. At SSSTC, 160㎥ of rainwater was recovered during the five months from November 2022. This amount is equivalent to about 2% of the water it used during the same period. The collected rainwater is reused as cooling water for air conditioning equipment, etc.