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About Toshiba > Social and Environmental Activities > Environmental Management > Eco Processes > Effective Use of Resources:
The goal of Toshiba Group is to reduce the amount of water it receives by 10% compared to the FY2000 level by FY2012.
The amount of water received per unit production in FY2008 was reduced to 75% of the FY2000 level, a 25% reduction. Greatly surpassing the goal of 8%. The amount of water received was about 56 million m3, about 600,000 m3 less than in the previous year.
By business sector, the semiconductor business received nearly half of the water. Therefore, Toshiba Group is pushing forward with initiatives for reducing water consumption in this area.
Specific measures include reusing water resources by introducing wastewater treatment and collection systems into semiconductor production bases that consume the most water and using a dry exhaust gas treatment process*.
By region, Japan accounts for about 90% of the total amount of water received, but for regions where water is in shorter supply, Toshiba Group will steadily reduce the amount of water it receives by setting separate goals on a region-by-region basis.
Since the Yokkaichi Operations uses PFCNote which is a greenhouse gas, the PFC gas emissions are decomposed and processed there to mitigate global warming. Because fluorine components after decomposing PFC were conventionally dissolved in water to ensure proper treatment, the Operations were forced to decrease acid drainage and service water to reduce the environmental burdens. To address this problem, a dry-type exhaust gas treatment equipment has been introduced to adopt a water-free treatment system, in which the fluorine components after PFC decomposition are immobilized in the form of calcium fluoride through a chemical reaction. Consequently, the amount of acid drainage was significantly decreased (900m3/day), and likewise the service water intake.
The Wuxi Company has implemented the reuse of waste water discharged from the pure water manufacturing process using a reverse osmosis membrane and EDINote with a view to improving the reuse rate of water resources. Despite the fact that a considerable amount of waster water was previously discharged after passing the reverse osmosis membrane and EDI, the Company has succeeded in reducing the quantity of service water by returning a certain amount of post-EDI-treatment waste water to a tank after treating the water with a first-class filter. This has resulted in a reduction of about 19 thousand tons in the volume of water used, compared with the previous year.
At the new 300mm-diameter-wafer-ready clean room facility at Yokkaichi Operations, measures to reduce the amount of wastewater have been included from the early stage of the design of the manufacturing process. Certain chemical substances are recovered by dedicated systems immediately after their use, in order to reduce the wastewater-treatment load and enable recycling of chemical substances. As a result, the amount of wastewater discharged from the clean room has been reduced from the initially anticipated 18,000m3 per day to 14,000m3 per day. Moreover, by recovering 70% of the wastewater through reverse osmosis membrane (RO) filtration, 10,000m3 of recovered water per day is reused as raw water for producing pure water or as water for the waste gas cleaning/cooling tower. As a result, the amount of intake of industrial water has been reduced from the initially anticipated 18,000m3 per day to 8,000m3 per day.
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