Year1
- 罐子材质：
- 碳钢
- 管件：
- 不锈钢
- 设备特点：
- 一体化
Type of sedimentation: ① Free sedimentation: The concentration of suspended solids in wastewater is not high, and it does not have coagulation properties. During the sedimentation process, the solid particles do not change shape or adhere to each other. Each completes the precipitation process independently.
(Initial sedimentation in the grit tank and primary sedimentation tank)
② Coagulation and sedimentation: The concentration of suspended solids in wastewater is not high, but it has coagulation properties. During the sedimentation process, they adhere and combine with each other. It becomes a larger floc, and its sedimentation speed changes. (In the later stage of the primary sedimentation tank and the early stage of the secondary sedimentation tank)
③Group sedimentation (stratified sedimentation): When the concentration of suspended particles in the wastewater increases to a certain level, the sedimentation of each particle will be interfered by its surrounding particles , the sedimentation speed is reduced. If the concentration is further increased, the interference between particles will be intensified. The particles with a large sedimentation speed cannot exceed the particles with a small sedimentation speed. Under the action of the cohesion force, the particle group combines into a whole and each maintains Relatively unchanged positions, sinking together. A clear interface is formed between the liquid and the particle population. The process of precipitation is actually the process of the interface falling. (Activated sludge settles in the later stage of the secondary sedimentation tank)
④ Compression sedimentation: At this time, the concentration is very high, and the solid particles contact and support each other. Under the gravity of the upper particles, the liquid in the gap between the lower particles is squeezed out At the interface, the solid particles are concentrated. (Concentration of activated sludge in the sludge hopper of the secondary sedimentation tank and the thickening tank)
Settling speed of particles: Obtained based on Stokes' formula.
Surface load of the sedimentation tank: /: The flow rate passing through the unit surface area of the sedimentation tank per unit time is generally called the surface load and is represented by . (Numerically speaking, it is the same as the particle sedimentation velocity)
Aeration grit tank: It is a long channel with an aeration device installed along the entire length of one side of the channel wall, away from the bottom of the tank, and a sand collection device at its lower part. bucket, the bottom of the pool has a slope of . to ensure that sand particles slide in. Due to aeration, organic particles in wastewater are often in a suspended state. The sand particles rub against each other and bear the shear force of aeration. The organic pollutants attached to the sand particles can be removed, which is beneficial to obtaining purer sand particles.
The method of the free sedimentation total removal rate test and the determination of the total removal rate: Stir the wastewater with measured suspended solids content evenly, and then inject it into several sedimentation tubes at the same time. After time, the wastewater from the first sedimentation tube A certain amount of wastewater is taken out from a high place, and similarly, it passes through,. . . After the time, correspondingly from No.,. . . The same amount of water samples were taken out from the same height in each sedimentation tube, and the suspended solid content was measured to be \\3. . . . The sedimentation rate is the sedimentation rate of suspended matter over time. Taking the sedimentation rate as the abscissa and the sedimentation rate as the ordinate, the relationship curve between sedimentation rate and sedimentation rate can be drawn.
Analysis of the working process of an ideal sedimentation tank: The assumptions are as follows: ① The wastewater in the tank flows in the horizontal direction, from the inlet to the outlet, the particles are evenly distributed horizontally, and each particle flows according to the horizontal flow rate ② The suspended particles are evenly distributed throughout the water depth , its horizontal partial velocity is equal to the horizontal flow velocity of wastewater, and the sinking speed of each particle is fixed. ③ Once the particles settle, they will no longer float. The sedimentation tank is divided into four parts: the inflow area, the outflow area, the sedimentation area and the sludge area.
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