Control method for backflow and dissolved oxygen of mixed liquid of MBR system

Abstract

The invention discloses a control method for the backflow and dissolved oxygen of mixed liquid of an MBR system. The method comprises a sewage treatment and discharge step and an oxygen-dissolved mixed liquid backflow control step. A control system on which the control method is based comprises a fan, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR membrane tank, a clean water tank, a first reflux pump, a second reflux pump, a third reflux pump and a reflux pipeline. According to the invention, dissolved oxygen in the aerobic tank, the anoxic tank and the anaerobic tank can be controlled within a proper range, so the nitrogen and phosphorus removal efficiency of the system is improved, water quality is stable and reaches the standard, effluent can meet ultrahigh standard discharge requirements, and the energy consumption of the system is remarkably reduced compared with the energy consumption of a traditional process.

Description

Technical field [0001] The present invention belongs to the field of sewage treatment, and more particularly to a MBR system mixture reflow and dissolved oxygen control method. Background technique [0002] Membrane bioreactor technology, that is, MBR sewage treatment process, is a product of membrane separation techniques and sewage biological treatment techniques. The technology has good water quality and stable, small area, less residual sludge discharge, unaffected by sludge expansion, strong impact load capacity, high automation, and easy operation management. With the improvement of water quality standards in the sewage treatment plant, the reduction in film production costs and the improvement of film performance, and the film bioreactor technology is increasingly concerned. However, with the decrease in film formation, the improvement in film performance, the problem of energy consumption is increasingly becoming the MBR process, and the problem of energy consumption on t...

AI Technical Summary

Problems solved by technology

However, with the reduction of membrane production cost and the improvement of membrane performance, the problem of energy consumption has increasingly become an MBR process, and the hindering effect of energy consumption on the MBR process has become more and more prominent.

Existing data show that the current average power consumption of urban sewage treatment plants in my country is 0.29kW h / m3, while the unit power consumption of MBR process sewage treatment plants is 0.6~0.9kW h / m3, much higher than traditional biological sewage treatment Process; According to statistics, in the MBR sewage treatment process, the energy consumption of the biochemical unit accounts for about 90% of the total energy consumption of the whole plant, and among them, the energy consumption of the blast aeration accounts for about 65% of the energy consumption of the biochemical unit ; In order to control the pollution of the membrane surface, the membrane surface needs to be purged intensively by means of blower aeration. Generally, the air-water ratio in the membrane pool is 10:1~20:1, and the dissolved oxygen concentration of the mixed solution is as high as 5.0 mg / L~10.0mg / L, if it is not used scientifically, it will not only waste the energy consumption of blast aeration and increase the cost of sewage treatment, but also consume a large amount of high-quality carbon sources that can be used in sewage, which is not conducive to Improve the effluent effect of the whole sewage treatment system

In the conventional MBR system, the mixed solution of the membrane pool is directly returned to the anoxic tank at the front end. Because the dissolved oxygen content in the membrane pool is too high, the dissolved oxygen content in the anoxic pool will exceed the normal value, which will affect the denitrification effect of the system.

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