Process overview: Sewage treatment process mainly includes three categories which is the physical and chemical method, activated sludge process, biological membrane method. The method includes dosing clarification, activated carbon adsorption method, ion exchange method and electrodialysis method etc.; activated sludge process including oxidation ditch, A2/O, SBR, AB process; biological membrane method including aeration biological filter and rotating biological contactor and contact oxidation pool and a biological fluidized bed process. Oxidation ditch is be used. It has been continuously developed because of its simple way to deal with the sewage and it also has achieved a lot of breakthrough. The whole process of oxidation ditch wastewater treatment such as water penetration, aeration, sedimentation and  

stabilization of sludge and effluent is concentrated in the oxidation ditch, the earliest oxidation ditch is without another primary sedimentation tank, secondary sedimentation tank and sludge reflux device. Later to deal with the scale and scope gradually expanded, it usually adopts the extended aeration, continuous access to water, produced by microbial sludge in aeration sewage purification as well as stable, do not need to set the initial sink tank and sludge digestion tank, treatment facilities is greatly simplified. Since 1980, much research about oxidation ditch has been carried out in our country, and it can’t agree with that oxidation ditch technology is a sewage biological treatment method with good effluent quality, reliable operation, low capital investment and operation costs, especially the closed cycle of pool type is really ideal for sewage nitrogen and phosphorus removal. And the developing countries like China, which has critical pollution and resource shortage, can combine the urban sewage treatment technology with high efficiency and low investment, which can achieve a certain treatment. Therefore, the oxidation ditch process will be worthy of our research, development and application.

Conclusion: According to the task book as the main technical information, through the process comparison finally determine the choice of oxidation ditch, strictly abide by the design principles, so that the design is reasonable, safe and reliable. Because of water shortages are increasingly affecting the our daily life, the protection of water resources, especially for sewage purification treatment and research work becomes very urgent and necessary, therefore, we look forward to future sewage treatment process design which can be more made for the benefit of all humanity.

KeyWords:sewage disposal;oxidation ditch;nitrogen and phosphorus removal

目  录

1 绪论 1

1.1 生活污水的来源与特点 1

1.2 生活污水的危害 1

1.3 污水处理的主要方法 1

1.4 设计依据 2

1.5 设计目标与要求 2

2 工艺流程的确定 3

2.1 污水处理工艺方案比较 3

2.1.1 SBR法 3

2.1.2 A2/O工艺 3

2.1.3 AB工艺 3

2.1.4 氧化沟法 4

2.2 污水处理工艺方案的确定 4

3 污水处理的工艺设计及计算 5

3.1 设计参数 5

3.1.1 设计处理量 5

3.1.2 设计进出水水质 5

3.2 粗格栅的计算