PROBLEM TO BE SOLVED: To effectively purify circulation water in a hydroponic system by simple apparatus.SOLUTION: A circulation path (11) for circulating circulation water can be switched either to a disinfection path (12) having a discharge part (62) for generating hydrogen peroxide by streamer discharge in the circulation water and a direct-current power supply (70) for applying the direct current voltage to the discharge part (62), or to a normal path (13) without circulation through the disinfection path (12). When the circulation water is polluted, the circulation water is made to flow through the disinfection path (12), and the circulation water is purified by applying the direct current voltage in the circulation water and generating hydrogen peroxide by the streamer discharge. Normally, the circulation water is circulated without flowing through the disinfection path (12).COPYRIGHT: (C)2012,JPO&INPIT【課題】水耕栽培システムの循環水を簡単な設備で効率よく浄化する。【解決手段】循環水を循環させる循環経路(11)を、循環水中でストリーマ放電を行って過酸化水素を発生させる放電部(62)及び放電部(62)に直流電圧を印加する直流電源(70)を有する除菌経路(12)と、この除菌経路(12)を経由させない通常経路(13)とのいずれかに切換可能に構成し、循環水が汚染されたときに、除菌経路(12)に循環水を通過させ、循環水中で直流電圧を印加してストリーマ放電を行って過酸化水素を発生させて循環水を浄化し、通常時には、除菌経路(12)を経由させないで循環水を循環させる。【選択図】図1
