Abstract: An oxidizing agent is added to water polluted with organic compounds, especially organic chlorine compounds, disinfection is carried out, and suspended solids in the water are removed. Thereafter, ultraviolet rays are irradiated to oxidize and decompose the organic compounds, and furthermore, volatile organic compounds are separated and removed from the water. Finally, the oxidizing agents residual in the water are reduced. The oxidizing agent is separately added at two phases of disinfection and oxidization decomposition, thereby causing the decomposing efficiency of organic compounds to be much improved.

Abstract: Raw water containing organic chlorine compounds is supplied in an aeration tank, wherein the organic chlorine compounds contained in the raw water are transferred into air or gas. The gas obtained from the aeration tank is collected in a treatment solution of a decomposition-treatment tank. The treatment solution contains an oxidizing agent and ultraviolet rays are irradiated to the treatment solution in the decomposition-treatment tank to activate the oxidizing agent, to thereby oxidization-decompose the organic chlorine compounds in the gas.

Abstract: Raw water containing organic chlorine compounds is supplied in an aeration tank, wherein the organic chlorine compounds contained in the raw water are transferred into air or gas. The gas obtained from the aeration tank is collected in a treatment solution of a decomposition-treatment tank. The treatment solution contains an oxidizing agent and ultraviolet rays are irradiated to the treatment solution in the deocmposition-treatment tank to activate the oxidizing agent, to thereby oxidization-decompose the organic chlorine compounds in the gas.

Abstract: Raw water such as polluted ground water can be recovered to clean water through the following processes. Firstly, oxidizing agent is added to raw water to disinfect bacteria, and then after suspended solid is removed from the water, ultraviolet rays are irradiated on the water so that organic chlorine compounds can be decomposed by active oxygen generated by the irradiation of ultraviolet rays. Finally, the residual oxidizing agent remaining in the treated water is reduced by activated carbon and catalytic resin. Further, the organic chlorine compound decomposition reaction is promoted at pH of 9 or below and in a temperature range of 15 to 30.degree. C.

Abstract: Method for observation of vibration mode in which a substance inclusive of structures and materials to be observed in vibration mode is vibrated, heat generated by giving vibration is held at the vibrating parts, infrared emission energy emitted from the substance is optically detected to visually display the distribution of temperature change at each vibrating part as thermal imagery.