(JP10005790-A)      A fluid purifying apparatus is shown in the figure 1 and comprises a light source (1), a carrier (2) for depositing photosynthetic bacteria and/or blue-green algae on, and a vessel (3) for housing a fluid to be purified, with at least the carrier (2) housed in the vessel. The fluid is purified by utilising the metabolic activity, induced by light irradiation from the light source (1), of photosynthetic bacteria and/or blue- green algae deposited on the carrier (2).    The carriers (2) comprise a transparent material which can be glass. They maintain their positions even when the fluid flows in the vessel (3). The external surface of the carrier (2) and/or the internal surface of the vessel (3) is/are uneven. The light source includes a transmission means for the light from the light source to the deposition location of the photosynthetic bacteria and/or algae. The light contains far UV and other wavelengths. An apparatus can comprise a vessel (3) having a double cylinder structure encircling the light source (1) and housing the carrier (2) in which the light source and the vessel are concentric and separable. The light source is held straight by a support attached to a straight support of the vessel. In this case the carrier positioned adjacent to the internal cylinder carries a photo-catalyst.    USE -   The apparatus is used for removing nitrogen compounds, phosphorus compounds, metallic ions and organic matter contained in domestic or industrial waste water.    ADVANTAGE -   The apparatus can satisfactorily purify waste water even if it contains low concentrations of e.g. nitrogen compounds, phosphorus compounds, metallic ions and organic matter.    (EP900766-A1)      A fluid purifying apparatus is shown in the figure 1 and comprises a light source (1), a carrier (2) for depositing photosynthetic bacteria and/or blue-green algae on, and a vessel (3) for housing a fluid to be purified, with at least the carrier (2) housed in the vessel. The fluid is purified by utilising the metabolic activity, induced by light irradiation from the light source (1), of photosynthetic bacteria and/or blue- green algae deposited on the carrier (2).    The carriers (2) comprise a transparent material which can be glass. They maintain their positions even when the fluid flows in the vessel (3). The external surface of the carrier (2) and/or the internal surface of the vessel (3) is/are uneven. The light source includes a transmission means for the light from the light source to the deposition location of the photosynthetic bacteria and/or algae. The light contains far UV and other wavelengths. An apparatus can comprise a vessel (3) having a double cylinder structure encircling the light source (1) and housing the carrier (2) in which the light source and the vessel are concentric and separable. The light source is held straight by a support attached to a straight support of the vessel. In this case the carrier positioned adjacent to the internal cylinder carries a photo-catalyst.    USE -   The apparatus is used for removing nitrogen compounds, phosphorus compounds, metallic ions and organic matter contained in domestic or industrial waste water.    ADVANTAGE -   The apparatus can satisfactorily purify waste water even if it contains low concentrations of e.g. nitrogen compounds, phosphorus compounds, metallic ions and organic matter.    (JP3125696-B2)      A fluid purifying apparatus is shown in the figure 1 and comprises a light source (1), a carrier (2) for depositing photosynthetic bacteria and/or blue-green algae on, and a vessel (3) for housing a fluid to be purified, with at least the carrier (2) housed in the vessel. The fluid is purified by utilising the metabolic activity, induced by light irradiation from the light source (1), of photosynthetic bacteria and/or blue- green algae deposited on the carrier (2).    The carriers (2) comprise a transparent material which can be glass. They maintain their positions even when the fluid flows in the vessel (3). The external surface of the carrier (2) and/or the internal surface of the vessel (3) is/are uneven. The light source includes a transmission means for the light from the light source to the deposition location of the photosynthetic bacteria and/or algae. The light contains far UV and other wavelengths. An apparatus can comprise a vessel (3) having a double cylinder structure encircling the light source (1) and housing the carrier (2) in which the light source and the vessel are concentric and separable. The light source is held straight by a support attached to a straight support of the vessel. In this case the carrier positioned adjacent to the internal cylinder carries a photo-catalyst.    USE -   The apparatus is used for removing nitrogen compounds, phosphorus compounds, metallic ions and organic matter contained in domestic or industrial waste water.    ADVANTAGE -   The apparatus can satisfactorily purify waste water even if it contains low concentrations of e.g. nitrogen compounds, phosphorus compounds, metallic ions and organic matter.