Zhengzhou City Sewage Purification Co., Ltd. Wang Xinzhuang sewage treatment plant project, primary sedimentation tanks a total of 4, the inner diameter of 55 meters, the height of the wall of 4.3 meters. Second sedimentation tanks total of 8, the inner diameter of 57 meters, the height of the wall is 4.75 meters. The thickness of the cast-in-place wall slabs of the primary and secondary sedimentation tanks is 25 centimeters, and the concrete strength class is C40.