PROBLEM TO BE SOLVED: To provide a circulation liquid control device and a method of controlling a circulation liquid capable of efficiently irradiating microbes contaminating a liquid phase with ultraviolet and improving the deactivation rate of the microbe even in the case of low ultraviolet transmittance of the liquid while maintaining a total amount of the liquid used circularly in a facility as long as possible.SOLUTION: There is provided a circulation liquid control device 10 used for a facility 2 comprising a circulation circuit 1 circulating the liquid in which microbes breed accompanying the use thereof. The device is equipped with: a classification part 20 separating by centrifugal separation, a microbe-including liquid circulating in the circuit 1 into a concentrated liquid in which the microbe is concentrated and a non-concentration liquid in which the concentrated liquid is removed a deactivation treatment part 30 deactivation-treating the microbe in the concentrated liquid classified by the classification part 20 by ultraviolet irradiation and a rotary flow part 40 returning the non-concentration liquid and the concentrated liquid after deactivation treatment into the circulation circuit 1.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2019,JPO&INPIT【課題】設備で循環使用される液の総量を可及的に維持しつつ、液の紫外線透過率が低い場合であっても、液相に混入した微生物に対して効率的に紫外線を照射でき、微生物の不活化率を向上させ得る循環液管理装置および循環液の管理方法を提供する。【解決手段】循環液管理装置10は、使用に伴って微生物が繁殖する液を循環させる循環回路1を備える設備2に用いられ、循環回路1を循環する液中の微生物を遠心分離により濃縮した濃縮液と該濃縮液を液から除いた非濃縮液とに分ける分級部20と、分級部20で分級された濃縮液中の微生物を紫外線の照射により不活化処理する不活化処理部30と、非濃縮液および不活化処理後の濃縮液を循環回路1中に戻す環流部40と、を備える。【選択図】図1
