IMPROVEMENT OF ANOXIC CONDITION ON BOTTOM WATER LAYER AND SEDIMENT BY SUPPLYING LIGHT WITH LIGHT EMITTING DIODE

Abstract

 In this study, the change in dissolved oxygen concentration in water by supplying light with Light Emitting Diode (LED)was investigatedon the column experiments. 12 red and 4 blue LEDs were used in this experiment. The irradiance was about 45 W/m². From the column experiment results, it was found that the dissolved oxygen concentration could be increase from about 0 mg/L to 11 mg/L through the photosynthesis of benthic diatom by supplying light with LED. It was also determined that the orthophosphate and silicate ion concentration in water decreased during the supply of light. Therefore, it should be possible to improve the condition of anoxic bottom water and reductive sediment surface by supplying light with LED.