An automatic adjustment device and adjustment method for the return flow of mixed liquid in a small purification tank

Abstract

The invention discloses an automatic adjustment device and adjustment method for the mixed liquid return flow of a small purification tank. The automatic adjustment device is equipped with an ultrasonic liquid level detection device in the water inlet tank, and the mixed liquid return tank is located at the bottom of the tank above the aerobic nitrification area. A number of solenoid valves are installed side by side, and the ultrasonic liquid level detection device and the solenoid valve are connected through the controller; the PLC regularly reads the water depth in the water inlet tank detected by the ultrasonic liquid level detection device, and calculates the average water depth for a continuous period of time. According to the average water depth and The ratio of the designed water depth controls the switch of the solenoid valve with a delay; when the ratio between the average water depth and the design water depth changes, the switch of the solenoid valve can be controlled with a delay through the PLC to realize the automatic adjustment of the water flow of the mixed liquid back to the anoxic denitrification zone . The invention proposes that the return flow of the mixed liquid can be automatically adjusted according to the actual water inflow of the small-scale purification tank, and at the same time, the dissolved oxygen in the anoxic zone can be controlled to provide anoxic conditions for denitrification and improve the denitrification efficiency of the purification tank.

Description

technical field [0001] The invention relates to a sewage treatment device, in particular to an automatic adjustment device and an adjustment method for the return flow of mixed liquid in a small purification tank. Background technique [0002] As China continues to promote the implementation of the new urban-rural integration and rural revitalization strategies, the treatment of rural domestic sewage has become a very important part of the improvement of the rural living environment. Compared with urban domestic sewage, the discharge of rural domestic sewage is relatively scattered, the collection is difficult, the treatment process is also different from that of urban domestic sewage, and the amount of funds required for treatment is large, resulting in a low treatment rate of rural domestic sewage in my country. It is very urgent to improve the rural living environment and improve the quality of village water environment. [0003] In the treatment of domestic sewage in rur...

AI Technical Summary

Problems solved by technology

However, due to the large time-varying coefficient of water inflow to small and medium-sized purification tanks in actual operation, that is, the inflow flow rate varies greatly, and the air-lift return flow rate of the purification tank is usually determined according to the design water volume, and cannot be adjusted with the actual water flow rate. Real-time adjustment; on the other hand, although the opening degree of the air lift valve can be adjusted, when the actual water inflow is less than the design flow, if the gas volume used for the gas lift of the mixed liquid is reduced according to the demand for the return flow, there will be gas volume in the actual operation. Unstable, frequently interrupted reflow conditions

Due to the above two reasons, the actual return flow of small purification tanks is usually much greater than the return flow required for denitrification and denitrification. Excessive return flow carries too much dissolved oxygen, which leads to high dissolved oxygen in the anoxic denitrification area and damages The denitrification conditions are not met, resulting in very low denitrification and denitrification efficiency of the small purification tank. Key Factors for Nitrogen Efficiency

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