Performance Of Aeration With Pure Oxygen For Quick Control Of Black And Odor In River And Influencing Factors

This thesis investigated and evaluated the effectiveness of pure oxygen aeration in controlling the"black and odor"in rivers in Dongguan city. The scale in Shipai Central River was 40,000 m3/d, while it was 120,000 m3/d in Shijie Central River. Different process parameters and different oxygen dosages were compared in experiments, the technical feasibility in eliminating the black and smelly of the tested rivers was tested, related factors including hydrodynamic conditions, sediment and operation cost were evaluated.Pure oxygen aeration experiments in Shipai Central River demonstrated that DO concentration can be quickly enhanced from 0 to 20mg/L, while the color and odor can be controlled below 20 and 5, separately, thus meeting the requirements of the general landscape water quality standard [GB12941-91]. Continuous operation tests showed this system could work steadily and was easy to manage.Experiments in Shijie Central River demonstrated that this pure oxygen aeration system can effectively control the odor below 5 and decrease the color to 15~20. The results in several special days with abnormal weather showed this aeration system was a good choice to improve and restore water qulity when sudden pollution accident occured, such as the deterioration of water qulity brought by rainstorm or tides.DO concentration declined from the river surface to the bottom. Sustained aeration may cause in situ inactivation of sediment. Laying plate under the nozzle can significantly prevented stirring the sediment, thus decreased the color, odor and the oxygen uptake rate. Hydrodynamics was one of the main influencing factors of the distribution of DO in the water. The higher the river flow rate, the lower the oxygen uptake rate, and the farther the effect lasted. The operation cost for the Shipai Central River was 0.05 yuan RMB per m~3, related efficiency of oxygen aeration reached to 90%, while for the Shijie central river, the operation cost was 0.020 yuan RMB per m~3~0.033 yuan RMB per m~3. The technology is cost-effective for engineering application.This research is of engineering significance to the effective control of black and odor in river in practice.