We plan to use a laundry drainage treatment system that combines a device using a manganese dioxide-based catalyst for ozone oxidation with a ceramic microfiltration membrane (MF membrane). The high oxidizing power of ozone is enhanced by the catalyst, and the impurities (such as chemical oxygen demand (COD) causative substances and n-hexane extracts) in the drainage are sufficiently degraded to allow their releases to the environment. Ionic nuclides are also oxidized and insolubilized so that they can be separated with the MF membrane having fine pores of about 0.1μm. The performance of the treatment system in removing zadioactivity, COD causative substances, and n-hexane extracts was confirmed by hot demonstration tests using actual laundry drainage. Cold tests were also conducted using simulated laundry drainage to confirm the system operation conditions and the long-term stability of drainage treatment capability. While ozone has a high oxidizing power, it decays spontaneously in liquid within a short period of time. Therefore, the behavior of ozone under the operating conditions and its effect on the corrosion of structural materials were investigated to maintain a sufficient time for decay and select appropriate structural materials.
