Views: 5 Author: Tuohai Pump Publish Time: 2022-09-22 Origin: www.txtuohai.com
The function of the collecting basin is to collect, store and balance the quality and quantity of wastewater.
The production wastewater of each workshop of the factory is generally unbalanced in the amount and quality of the discharged wastewater. There is wastewater during production, and there is no wastewater when it is not in production. Even within a day, there may be great changes, especially In the wastewater of the fine chemical industry, if the clear and wastewater is not separated, the water quality and quantity of the process concentrated wastewater and lightly polluted wastewater will change greatly. This change is very detrimental to the normal operation and treatment effect of wastewater treatment facilities and equipment, and even harmful.
Therefore, before the wastewater enters the main sewage treatment system, a wastewater collecting basin with a certain volume must be set up to store the wastewater and make it homogeneous to ensure the normal operation of the wastewater treatment equipment and facilities.
The volume of the collecting basin of the sewage pumping station should be determined according to the change of the incoming flow, the type, number, and working system of the selected sewage pump, the operation nature of the pumping station, and the starting time. If the volume of the collecting basin is too large, it will cause a large amount of sediment in the pool and increase the project cost. The volume is too small and cannot meet the requirements of water regulation. Therefore, the volume of the collecting basin should be reasonably determined according to the above conditions.
The volume of the collecting basin should meet the installation requirements of hydraulic layout, grille, and sewage lifting pump suction pipe. On the basis of timely pumping away the incoming sewage and avoiding frequent opening and closing of the pump, the volume should be reduced as much as possible to reduce costs and reduce pollution, siltation, and decay in the pool.
The volume of the collecting basin includes two parts: dead water volume and effective volume. Dead water volume refers to the volume below the lowest water level, and effective volume refers to the volume between the highest and lowest water levels in the collecting basin. According to the drainage specification, the effective volume of the collecting basin should meet the following requirements:
For large sewage pumping stations that operate all day and night, the effective volume of the collecting basin shall not be less than the water output of the largest pump in the pumping station for 5 minutes. If the pump unit is automatically controlled, the high-flow submersible pump should not be started more than 6 times per hour, and when it is manually managed, the pump should not be started more than 3 times per hour.
For small sewage pumping stations, due to the small flow of sewage at night, it may stop running at night. In this case, the volume of the collecting basin must be able to store the inflow during the period when the operation is stopped at night.
For the collecting basin of the sewage pumping station in the factory, its volume should also be reviewed against the short-term shower drainage.
The volume of the collecting basin in the sewage mud pump room shall be calculated and determined according to the amount of sludge discharged at one time and the pumping capacity of the mud pump. The volume of the sludge collection tank in the activated sludge pump room should be calculated and determined according to the amount of returned sludge discharged, the amount of excess sludge, and the pumping capacity of the sludge pump.
If the pump control cabinet of the pumping station can automatically control the start and stop of the water pump according to the liquid level of the collecting basin, the effective volume can be calculated according to the water inflow of the collecting basin and the pumping time of each pump.
The calculation formula is:
Vmin - The minimum effective volume of the collecting basin (m3)
Tmin——The minimum working cycle of the pump (s)
Q——Pump flow (m3/s)
The pumps in the collecting basin can choose the submersible sewage pump, submersible axial flow pump, etc. The selection of the pump should be determined according to factors such as the design flow and the required lift, and should meet the following requirements:
The same type of water pump should be used, and the number of pumps should not be less than 2, and should not be greater than 8. When the water volume varies greatly, pumps of different specifications can be configured, but not more than two, or use the frequency conversion speed control device, or use a blade-adjustable pump.
The sewage pumping room and the combined sewage pumping room shall be provided with backup pumps.
If the number of working pumps in the collecting basin is not more than 4, the spare pump should be 1.
If the number of working pumps in the collecting basin is not less than 5, the number of spare pumps should be 2.
If there are 2 spare pumps in the submersible pump room of the collecting basin, one can be spared on site and one can be spared in stock.
The pump room of the rainwater sump may not be provided with a backup pump.
In the rainwater sump pump room of the interchange road, the importance of the pump room shall be set as a backup pump.
According to the above requirements, it can be concluded that the factors that affect the backup pump of the collecting basin are:
The location of the collecting basin
Design of the Pump Room
Model of Working Pump
Number of Working Pumps
In addition, if the amount of sewage or rainwater is relatively small, an integrated pump station can be used to replace the sump and pump room, which greatly saves costs.