A fluid treatment apparatus particularly for sterilizing drinks comprises an elongate tubular duct (110) and an elongate UV light source (111) extending longitudinally of the duct (110). The fluid flows longitudinally of the duct (110) in a thin annular low passage (114) which extends around the UV light source (111). A mixing device (112) disposed between adjacent longitudinal portions of the duct (110) for diverts all of the fluid flowing along a first portion of the passage (114) through fluid mixing means (113,116) in the device (112) and returns the mixed fluid to a second portion of the passage (114). Micro-organisms in the thin flow of fluid are killed as they come within close proximity of the light source (111). The mixing device (112) causes all of the flow to be thoroughly mixed and returned to the flow passage (114). The provision of a plurality of mixing devices along the length of the duct (110) increases the likelihood that all microorganisms receive a sufficient lethal dose of UV radiation.特に飲料を殺菌するための流体処理装置は、細長い管状の導管(110)と導管(110)の長手方向に延びる細長いUV光源(111)を含む。流体は、導管(110)の長手方向に、UV光源(111)の周囲に延びる薄層の管状流路(114)を流れる。導管(110)の長手方向に隣接する部位の間に配置された混合装置(112)は、流路(114)の第一の部位に沿って流れる流体の全てをこの装置(112)内の流体混合手段(113、116)によって方向転換し、混合した流体を流路(114)の第二の部位に戻す。薄層の流体の流れの中の微生物は、光源(111)に接近すると殺菌される。混合装置(112)は、流れのすべてを徹底的に混合し、流路(114)に戻す。導管(110)の長さに沿って複数の混合装置を設置することで、すべての微生物が充分な致死量のUV放射線を受ける可能性が増大する。
