| 摘要 |
PROBLEM TO BE SOLVED: To enhance recovery efficiency of fluorine by filling an ion exchange resin in a waste water chamber of an electrodialysis device, electrodialyzing the waste water and recovering the fluorine in the waste water as hydrogen fluoride. SOLUTION: The waste water discharged from a semiconductor production process system 3 is exchanged the heat generated with a distiller 7 with a heat exchanger 4 to be raised the liquid temperature, and is fed to an UV ray generator 5 in the state further raised the liquid temperature with the heat generated with the electrodialysis device 10 via an electrodialysis cooling system 11. The UV ray generator 5 decomposes trimethyl amine contained in the waste water and the waste water is fed to a catalyst tower 8, and hydrogen peroxide in the waste water is decomposed with a ruthenium catalyst. When the concentration of the hydrogen fluoride being a main component of the hydrogen peroxide is more than 0.1%, the waste water is fed to an ion exchange membrance of the electrodialysis device 10, then the hydrogen fluoride is treated and recovered. Thus, the recovery efficiency of fluorine is enhanced.
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