Author(s): Kohji Michioku
Linked Author(s): Kohji Michioku
Keywords: Reservoir eutrophication; Deoxygenation; Decomposition of organic matters; Aeration; Water purification
Abstract: Metalimnion became anoxic in a eutrophic reservoir during the warm season, although the hypolimnion became successfully aerobic by an aeration system. Since drinking water is withdrawn from the anoxic metalimnion, the performance of the water purification plant has recently declined. The three types of aeration systems, (i) air diffuser system, (ii) air bubbler destratification system and (iii) air bubble jet system, were evaluated for their performance as countermeasures against deoxygenation of the reservoir metalimnion. In the water quality model, physical processes such as dissolved oxygen dilution and vertical mixing caused by aeration were taken into consideration in addition to hydrodynamics and biochemical processes regarding to water quality. After the model was verified through a comparison with the field data, the water purification performance was investigated for the three types of aeration systems with various capacities. In this study, difference of dissolved oxygen concentration before and after the aeration was taken as an indicator of aeration performance. Furthermore, in order to analyze the cost performance of the system in addition to the mechanical performance, cost benefit was measured by the variable considering the initial and running costs of each aeration system. The air bubbler destratification system was found to have the highest cost benefit performance among the three.
Year: 2013