Study On Impact Of Artificial Structure On Oxygen Recovery And DO Diffusion

Fully utilizing river' s own energy to reaerate for river, increase the DO concentration of city river polluted water and improve the water quality by the riverway artificial structures, such as dams and weirs, this is a effective method which is of tremendous social and economic benefit. It conforms to the developing status of our country, and also may be one of the most potential choice in the city river pollution treatment .This paper investigates the reaeration ability of riverway artificial structure and determines the optimum shape of artificial structures, primarily recurring to the laboratory model experiment and field measurement, and uses the curve dam with WES standard profile and rubber dam as investigative objects. Primary work includes, 1.curve dam laboratory model*The research is sponsored by the Project of National Natural Science Foundation(50079013).experiment: respectively measures the reaeration ability of the smooth overflow surface and roughened overflow surface(hemispheroidal surface and stepped surface), and analyses contrastively the effect and reason of reaeration improving after roughened modification. 2.Fu Nan River rubber dam prototype measurement: respectively measures the upstream and downstream DO concentration of three rubber dams, which are located in the Jiu Van Bridge, Old South Gateway Bridge and Bai Hua Tan park, and along the river bank, measures the DO concentration of points downstream each dam. Finally, plot the relationship chart of DO concentration versus distance. 3. rubber dam laboratory model experiment: respectively measures the reaeration ability of smooth overflow surface and roughened overflow surface(stepped surface), then contrastively analyses the effect and reason of reaeration improving after roughened modification, and the reaeration effect between curve dam and rubber dam. 4.QUAL2E Model water quality simulation: respectively simulates the relationship of DO and BOD versus distance, under of the regime that constructing the rubber dam or not and modificating the overflow surface or not. contrastively analyses the influence of DO and BOD concentration on Fu Nan River water body during each regime, lastly describes and explains the role and significance of rubber dam in the city river pollution treatment.For the first time, this paper performs the reaeration prototype measurement of rubber dam, and obtains substantial important data. Picks out the optimum overflow surface with better reaeration effect(stepped surface), through carefully analyzing the results of experiment. The construction of rubber dam and roughened overflow surface can remarkably improve theDO amount of Fu Nan River, thus enhances the self-purifying ability of water. The conclusion of this paper confirms the feasibility of optimizing the shape of artificial structures for improving the river' s reaeration, and provides powerful foundation for scientific decision-making and project selecting, also can provide basis of check and revision for the three dimensional numeric simulation of turbulent field and the shape optimizing of artificial structure, which also belong to the content of National Natural Science Foundation Project(NO. 50079013).