| 摘要 |
PROBLEM TO BE SOLVED: To provide a treatment method for waste liquid which removes hydrogen peroxide contained in waste liquid containing acids or bases and hydrogen peroxide without distillation or neutralization treatment.SOLUTION: The treatment method includes: an irradiation process where ultraviolet rays are irradiated to the waste liquid to decompose the hydrogen peroxide contained therein; a measurement process where the hydrogen peroxide concentration of the waste liquid having been subjected to the irradiation process is measured; and a control process where the hydrogen peroxide concentration measured in the measurement process is compared with a reference value of the hydrogen peroxide concentration and when the measured concentration exceeds the reference value, at least one step selected from the following (a), (b) and (c) is performed: (a) starting to return the waste liquid having been subjected to the irradiation process and mix the returned waste liquid with the waste liquid before the irradiation process, or increasing the returning amount and mixing amount; (b) changing an ultraviolet irradiation condition to the waste liquid in the irradiation process to one where the decomposition of the hydrogen peroxide is accelerated; and (c) starting to add an accelerator for accelerating the decomposition of the hydrogen peroxide by the ultraviolet rays to the waste liquid before the irradiation process, or increasing the amount of added accelerator. |
