Cylinder flocculation sedimentation tank Wastewater impurity sedimentation equipment
Vertical flow sedimentation tank, also known as vertical sedimentation tank, is a sedimentation tank in which wastewater flows vertically in the pool. The plane figure of the pool body is circular or square, and the water enters the pool from top to bottom through the water inlet pipe in the center of the pool (the flow rate in the pipe should be less than 30MM/S). An umbrella-shaped baffle is set under the water inlet pipe to make the waste water flow evenly in the pool After distribution, it rises slowly along the entire cross-section (for domestic sewage, it is generally 0.5-0.7MM/S, and the settling time is 1-1.5H).
The suspended matter settles into the conical sedimentation bucket at the bottom of the pool, and the clarified water flows out from the surrounding overflow weir around the pool. A baffle and a scum tank are installed in front of the weir to retain the scum to ensure the quality of the effluent. On one side of the pool, a mud discharge pipe (with a diameter greater than 200MM) is set against the wall of the pool to discharge the mud regularly by hydrostatic pressure. The advantage of the vertical flow sedimentation tank is that it occupies a small area and is easy to discharge mud. The disadvantage is that it has a large depth, difficult construction and high cost. It is often used in sewage treatment plants with water volume less than 20000M3/D.
The working principle of the vertical flow sedimentation tank: In the vertical flow sedimentation tank, the sewage flows vertically from bottom to top at the flow velocity v, and the suspended particles in the sewage have the following three states of motion:
When the particle sinking speed u>v, the particles will settle down with the difference of u-v, and the particles can be removed;
When u=v, the particle is in a random state, neither sinking nor rising;
When u<v, the particles will not be able to settle down, but will be carried away by the rising water.