PROBLEM TO BE SOLVED: To provide a liquid treatment device and a liquid treatment method provided with an immersion type membrane filtration apparatus capable of performing the separation treatment for a liquid including a solid content and the ultraviolet irradiation treatment as well.SOLUTION: Provided is a liquid treatment device 1 comprising: an immersion type membrane filtration apparatus 12 having a flat type filtration membrane 36 and whose inside is installed with an emitter 34 with the shape of a sheet or the like emitting ultraviolet light by microwaves； and a microwave generator 14, where, while irradiating the emitter 34 with the microwaves generated by the microwave generator 14, the liquid to be treated including a solid content is passed through the membrane filtration apparatus 12, and the ultraviolet irradiation treatment is performed together with the solid-liquid separation treatment of the solid content of the body to be treated.SELECTED DRAWING: Figure 1【課題】固形分を含む液体の分離処理とともに紫外線照射処理を行うことができる、浸漬型の膜ろ過装置を備える液体処理装置および液体処理方法を提供する。【解決手段】平型のろ過膜３６を有し、マイクロウェーブにより紫外線発光する板状等の発光体３４が内部に設置された浸漬型の膜ろ過装置１２と、マイクロウェーブ発生装置１４と、を備え、マイクロウェーブ発生装置１４により発生させたマイクロウェーブを発光体３４に照射しながら、固形分を含む被処理液体を膜ろ過装置１２に通液させて、被処理液体の固形分の固液分離処理とともに紫外線照射処理を行う液体処理装置１である。【選択図】図１
