To make it possible to recycle a treating liquid by electrolyzing used treating liquid after a substrate is subjected to washing or surface treatment by using a liquid chemical for surface treatment consisting of culture media containing iron bacteria, removing impurities by electrodeposition from the inside of the treating liquid and reducing the iron ions in the treating liquid.
An electrode cell for generation which is separated to an anode chamber and a cathode chamber by a cation exchange membrane and a DC power source which energizes the anode in the electrode camber and the cathode in the cathode chamber are provided. A prescribed liquid is supplied to the anode chamber and the used treating liquid after the substrate is subjected to washing or surface treatment by using the liquid chemical for surface treatment consisting of the culture media containing iron bacteria is supplied to the cathode chamber and the impurities are removed by electrodeposition from the treating liquid by electrolyzing the treating liquid. In addition, the iron ions in the treating liquid are regenerated by reduction. The potential of the cathode is set at a potential sufficient for electrodepositing the metal impurities included in the treating liquid at the time of washing and surface treatment and reducing ferric ions to ferrous ions and is maintained at a potential at which the ferrous ions are not electrodeposited.
WATANABE AKIRA
MIYA AKIKO
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