A recirculation hybrid system is provided to reduce investment cost and operating cost by maximizing the synergistic effect of the hybrid system comprising a photocatalytic reactor and a biofilter, thereby minimizing the design scale of the biofilter or the photocatalyst reactor. A recirculation hybrid system comprises: an introduction part including a process waste gas flow meter(3) and an electrochemical real-time concentration analyzer(4) for calculating a pollutant load of volatile organic compounds and odor sources; a new photocatalyst reactor(24) for removing the volatile organic compounds and odor sources when the pollutant load is larger than the designed maximum elimination capacity of the biofilter; a recirculating blower(10) for recirculating waste gas to be treated to dilute the waste gas to be treated into process waste gas when it is impossible to biologically treat the waste gas since waste gas flown into the biofilter contains pollutants with too high concentration; and a biofilter(13) for oxidizing and decomposing the pollutants by microorganisms.
