The following is a description of the design calculation: 1. Water flow design parameters of coagulation sedimentation tank (1): determined according to actual needs. (2) Total volume: calculated according to water flow and residence time. (3) Pollutant production per unit volume: obtained from measured data. (4) Dosage: The decision should be made according to the instructions provided by the pharmaceutical manufacturer. 2. Calculation formula of coagulation sedimentation tank (1) Initial water quality index SSi = actual added SS concentration x 1000 ÷ total volume (2) Final water quality index SSf = (initial water quality index -SS removal rate) ÷ (1-SS removal rate) (3) unit. (2) Operating instructions: ① Determine the flow rate of treated water and the quality of pollutants, and calculate the total volume of coagulation sedimentation tank. ② Introduce sewage into coagulation sedimentation tank through water inlet, and add chemicals to the water inlet for mixing. (3) After a period of time, when the dirt settles to the bottom, remove the upper water. (4) Repeat the operation of step 3 as needed until the therapeutic effect is achieved. The above is the basic design and operation instructions of coagulation sedimentation tank, and the specific parameters should be adjusted according to the actual situation.
In the design of coagulation sedimentation tank, the commonly used calculation formulas of agitator's speed, flow rate, flow velocity, residence time and other parameters are as follows:
1. agitator speed: usually determined according to the size and concentration of solid particles in sewage. Larger particles need strong stirring force to be suspended in water. Generally speaking, the speed of the mixer can be preliminarily estimated according to the following formula:
n = (P/V)0.33
Where n is the rotational speed of the mixer in rpm；; P is the stirring power in w; V is the volume of the coagulation tank in cubic meters (m)? .
2. Flow rate and velocity: It can be determined according to the treatment requirements and the size of the coagulation tank. Generally speaking, the design should ensure that the wastewater stays in the coagulation tank for a long time and the wastewater flow rate cannot be too fast. Commonly used formulas include:
Q = AVC
Where q is the wastewater flow, and the unit is m? /h； A is the cross-sectional area of the coagulation tank, in meters (m)? ; V is the retention time of wastewater in the coagulation tank, and the unit is h; C is the concentration of wastewater pollutants in mg/L.
3. Retention time: usually determined according to the size and treatment requirements of the coagulation tank. In general, the residence time should meet the settling time of suspended solids and particles in sewage and ensure the full reaction of chemicals. Commonly used formulas include:
V = Q × t
Where, V is the volume of coagulation tank, and the unit is m? ; Q is the waste water flow, in m? /h； T is the residence time in h.
It should be noted that these formulas are only preliminary methods for estimating or calculating a certain parameter value in the coagulation sedimentation tank, which need to be comprehensively considered and adjusted in combination with specific conditions in actual design. If you need to know more about the specific design scheme, please consult professional engineers or enterprises.
Thank you for your trust. The above is my reply. I hope I can help you. Please remember to like it if it is useful. I wish you a happy life ~?