After upgrading waste water one times by the pump, the design finished the sewage whole treatment process by gravity flow to avoid repeating sewage upgrade in order to reduce losing power, decrease the cost of wastewater treatment and manage the operation easily.

In accordance with the established process, the design selects the process parameters of structures (including the grating, grit chamber cyclone, Carrousel oxidation ditch, secondary sedimentation tank and sludge thickening tank) and calculates the main size, the hydraulic loss, select the diameter and finished of Introduction of  Design Process, Process Flow Diagram, Factory Layout and Main Monomer Structure Map.

The project cost 30 million Yuan. The design is technically feasible and economically reasonable results.  As Carrousel oxidation ditch of the depth shallower, and no primary sedimentation tank, the civil engineering costs less, while operation and management of the process simple, high degree of automation reduces the cost of operation and management, so the whole process has total investment of less stable , Equivalent to the sewage treatment costs 0.47 Yuan / m3. The project make it less secondary pollution , good effect , energy consumption etc. and to ensure that wastewater discharge standards.  

The treated wastewater is expected to achieve <urban sewage treatment plant emission standards>（GB18918-2002）, emission standards at the national level:BOD5≤20mg/L，CODcr≤60mg/L，SS≤20mg/L，NH3-N≤8mg/L，TN≤20mg/L, reducing emissions to the environment each year for the 1752 tons COD .The polluted water has been greatly improved, to eliminate pollution, protect the environment and make benefits to human beings.

Keywords: Wastewater Treatment; Carrousel oxidation ditch; biological method; Nitrogen removal

目  录

1绪论 1

1.1 概况 1

1.2 设计依据与原则 2

1.2.1 设计依据 2

1.2.2 设计原则 2

1.3 设计规模和目标 3

2污水处理工艺的选择 3

2.1主体工艺 3

2.1.1 普通活性污泥法 3

2.1.2 氧化沟 4

2.1.3  A2/O法 5

2.1.4  AB法 5

2.1.5  各工艺之间比较 6

2.2二沉池 8

2.2.1 平流式沉淀池 8

2.2.2 竖流式沉淀池 8

2.2.3  辐流式沉淀池 8

2.2.4  各沉淀池之间比较 9

2.3沉砂池 9

2.3.1 平流沉砂池 10

2.3.2曝气沉砂池 10

2.3.3  旋流沉砂池 10

2.3.4  各沉砂池之间比较 10

2.4污泥浓缩 11

2.4.1 重力浓缩法 11

2.4.2 离心浓缩法 11

2.4.4  各浓缩池之间比较 12

2.5消毒工艺 12

2.5.1 紫外线消