2008 Volume 45 Pages 121-129
In this study, a method of using high-dissolved-oxygen water to purify bottom sediment in closed body water was confirmed to be effective. In addition, the prevention of phosphorus release from the bottom sediment using high-dissolved-oxygen water was also conducted. A pilot-scale oxygen dissolver was set up at the damreservoirs in Yamaguchi, Japan and an on-site study was performed at two water quality (the first stages of thermocline formation and the thermocline formation after a month). The results indicated that when starting with the first stages of thermocline formation, it was possible to spread the high dissolved oxygen water across the bottom layer without any diffusion in the upper direction. Furthermore, the existence of high dissolved oxygen water could prevent the release of phosphorus from the bottom sediment. On the other hand, after a month from the thermocline formation, the decrease of the diffusion distance by the production of the brown floc in the pilot-scale oxygen dissolver was detected. Therefore, itis better to introduce the high-dissolved-oxygen water from the first stages ofthermocline formation than the thermocline formation after a month. This study revealed the effectiveness of high dissolved oxygen water for the improvement in the water quality of closed body water.
