The process of sewage treatment is : firstly, coarse screen intercepts bigger particle and impurity, and the sewage inflow to pumping station, then from the pumps to fine screen, and then inflow to cyclone grit chamber, then entering the A2/O reactor. Through anaerobic-anoxic-aerobic process, using activated sludge to degrade organic compounds in sewage, also remove nitrogen and phosphorus. Then the sewage entering the sedimentation tank to separate sludge and sewage, the sewage is disinfected by UV, then outlet by achieving “Urban sewage treatment plant emission standers”(GB 18918-2002).

The process of sludge treatment is : excess sludge from sedimentation tank gets into store mud pool, through pipes and pumps, returned sludge re-enter A2/O reactor. The sludge is dehydrated by centrifuge, and the sludge cakes is treated.

KeyWords: A2/O process,;nitrogen and phosphorus removal;sewage treatment ;sludge treatment 

 目  录

1 前言

1.1 城市污水和城市污水处理厂 1

2 工程概况 2

2.1 设计进水水质和水量 2

2.2 设计出水水质 2

2.3依据和原则 2

2.3.1 主要参考技术标准和规范 2

2.3.2 设计原则 3

2.4设计要求和目标 3

3 污水处理工艺流程的选定及说明 4

3.1工艺流程选择的依据 4

3.2 工艺流程的选定 4

3.2.1 A2/O工艺 4

3.2.2 氧化沟工艺 5

3.2.3 SBR工艺 6

3.2.4 适合于中小型污水处理厂的除磷脱氮工艺的比较 7

3.2.5 工艺流程的选定 9

3.3 A2/O法同步脱氮除磷工艺的原理 9

4 污水处理工艺设计与计算 10

4.1 污水处理工艺流程 10

4.2 工艺计算 10

4.2.1 设计流量 10

4.2.2 格栅 10

4.2.3 提升泵房 13

4.2.4 集水间计算 13

4.2.5 旋流沉砂池 13

4.2.5 A2/O反应池 13

4.2.6 二沉池 19

4.2.7 紫外线消毒 20

4.2.8 污泥泵房设计 21

4.2.9 贮泥池 22

4.2.10 污泥浓缩脱水 22

5 污水处理厂平面布置和高程布置 23

5.1 平面布置 23

5.2 高程布置 24

5.2.1污水处理构筑物的水头损失计算 24

5.2.2 管渠水头损失 25

5.2.3 污泥处理构筑物高程计算 26

6 工程概预算和经济技术指标 27

6.1 土建费用 27