2000 Volume 44 Pages 1119-1124
A water purification system was developed and installed in the lower layer of a eutrophic reservoir. A preliminary test was conducted in order to examine its performance. The aerator generates fine air bubbles of several ten micro millimeters, so-called micro-bubbles. Dissolved oxygen, temperature, electric conductivity and other water quality items have been measured in every two weeks after starting the micro-bubble aeratin in March 1999. Despite continuously operating the system, total amount of dissolved oxygen in the reservoir has decreased so far, from which the air discharge is estimated to be less than oxygen consumption due to decomposition. Nevertheless, DO concentration in the lower layer is higher than that observed in the last four years, while DO in the surface layer has been kept less than that in the last four years. These results suggest that the system functions for aerating water body to some extent, except that the air discharge is not sufficient for complete aeration, yet.
