PROBLEM TO BE SOLVED: To provide a water quality improvement device capable of improving water quality in a closed water area by suppressing the generation of a large quantity of floating cyanophyceae in the whole closed water area such as a dam, a lake and the like due to comparatively low cost and simple constitution.SOLUTION: A water quality improvement device 1 constituted so as to suppress the propagation of floating cyanophyceae includes: a hull part 10 being movable in a water area inhabited with the floating cyanophyceae and having a twin hull part 20； a vibration blade part 50 being a propulsion part disposed in the hull part 10； an ultrasonic irradiation part 30 being disposed between the twin hull parts 20 and irradiating ultrasonic waves to the floating cyanophyceae； and a pair of flow control plates 70 being disposed at the twin hull parts 20 and controlling the flow state of the floating cyanophyceae for guiding the floating cyanophyceae to a region having the high sound pressure of ultrasonic waves.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】比較的低コスト且つ簡単な構成により、ダムや湖沼等の閉鎖水域全体における浮遊性藍藻類の大量発生を抑制することによって、閉鎖水域の水質を改善することが可能な、水質改善装置を提供する。【解決手段】本発明は、浮遊性藍藻類の繁殖を抑制すべく構成された水質改善装置１であって、浮遊性藍藻類の生息する水域を移動可能な、双胴部２０を有する船体部１０と、船体部１０に設けられた推進部たる振動翼部５０と、双胴部２０の間に設けられた、浮遊性藍藻類に超音波を照射する超音波照射部３０と、双胴部２０に設けられた、超音波の音圧が高い領域に浮遊性藍藻類を誘導すべく浮遊性藍藻類の流動状態を制御する、一対の流動制御板７０とを備えている。【選択図】図１
