Abstract: A method for treating waste water containing nitrate ion which comprises supplying raw waste water from a tube (2), formalin from a tube (3) and an aqueous alkaline solution from a tube (4) to a mixing vessel (1), while agitating with an agitator (5), so the resultant mixture has a pH of 7 or higher, transferring the mixture from an outlet pipe (6) to a catalyst bed (9) through a tube (8) by a pump (7), and discharging the treated fluid drained from the catalyst bed (9) to the outside of the system through pipe (11), wherein the catalyst bed (9) is provided within a jacket (10), through which a liquid such as water flows, for the temperature control, and is packed with a support type catalyst comprising spherical type activated carbon and Pd—Cu supported thereon. The type of reactor containing the support type catalyst in the catalyst bed (9) may be a fluidized bed or a fixed bed.

Abstract: Disclosed is a method of disposal of metallic aluminum-containing solid waste comprising the steps of reacting radioactive solid waste containing metallic aluminum with an alkali solution to generate a hydrogen gas and then mixing the resulting reaction liquid with a solidifying material containing a latent hydraulic material as a main component to solidify the liquid. According to the method of the invention, solidification of aluminum-containing radioactive solid waste in a highly filled state (high concentration) is feasible and a solid having excellent mechanical strength and properties of preventing oozing of radioactive nuclide can be obtained.

Abstract: There are provided a solidifying material used for radioactive waste which comprises a latent hydraulic material, an ultra-fine powder substance and a dispersing agent, and a process for the solidification of radioactive wastes which comprises kneading the above solidifying material with a cure stimulating agent, radioactive waste and, as occasion demands, water, and then curing the mixture by aging. Since the solidifying material of the present invention has excellent properties such as large treating capacity, excellent water resistance and large compressive strength, not only temporary storage but also permanent storage of radioactive wastes can be made.