Three-segment biological treatment process and device for sewage

Abstract

The invention relates to improvement of the existing three-segment biological denitriding process for sewage and provides a three-segment biological treatment process and device for sewage. The process is characterized in that an anaerobic phosphorous-releasing treatment unit is added before the three-segment biological denitriding process is carried out, and another water intrusion mixed unit isadded before denitrification is carried out. The treatment device is characterized in that an aeration nitration-segment sedimentation basin and an aeration-segment sedimentation basin which are in three-segment biological treatment are alternatively arranged at two ends, the other treatment unit pools are arranged between the two sedimentation basins and are subjected to series connection and parallel connection combination according to a treatment process flow, and simultaneously, the head and tail units of the treatment process are arranged in adjacency. By the process and device, the advantage of high-efficiency denitriding when the original three-segment biological treatment device conducts piecewise control and operation is retained, and a dephosphorization function is increased at the same time; enough carbon sources required for denitrification reaction are ensured by back-segment water ingress in no need of additionally supplementing and adding the carbon source, thereby reducing operation 5%-10% of operation cost; a structure that the sedimentation basins are arranged at the two ends, series connection and parallel connection treatment units are arranged in the middle isadopted, thereby saving occupied area and construction investments to the greatest extent, and under the same water treatment amount, the occupied area can be saved by about 20%, and the constructioninvestment of the treatment pool can be saved by about 15%.

Description

technical field [0001] The invention relates to the field of sewage treatment, and is an improvement to the existing sewage three-stage biological denitrification process, especially relates to the ability to effectively reduce operating costs (without adding carbon sources), and effectively remove phosphorus, and meet the requirements of low nitrogen and low phosphorus in sewage treatment effluent The required three-stage biological treatment process of sewage, and the device for three-stage biological treatment of sewage with less land occupation and investment. Background technique [0002] The three-stage biological denitrification technology is an efficient denitrification process for the degradation of organic matter in sewage. It is composed of an independent organic matter oxidation degradation section, nitrification section and denitrification section in sequence (the basic process is as follows: figure 1 ). The feature of this process is that the oxidative degrada...

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Problems solved by technology

However, since the denitrification section of this process is set after the organic matter oxidation section and nitrification section, the efficiency of denitrification mainly depends on the endogenous respiration carbon source, and an external carbon source is usually required to ensure an efficient and stable denitrification reaction, and the external carbon source is continuously added. It leads to relatively high operating costs; in addition, due to the addition of carbon sources, it may also cause the COD of the treated water to exceed the standard

Secondly, although the system has a good denitrification effect, due to the lack of anaerobic phosphorus release process section, the phosphorus removal effect is very poor, and it is difficult to meet the current low-nitrogen and low-phosphorus standards for sewage treatment.

Furthermore, each section of the reaction zone is built separately from the sedimentation tank, resulting in a large area and low land utilization rate, and the total length of the pool wall in the separate tank construction is long, resulting in high construction investment costs

[0003] Chinese patents CN101570383 and CN201587897U deep denitrification and dephosphorization device and process control method, which are aimed at the inability of synchronous deep biological dephosphorization in the existing A / O segmented water inlet process, and the inverted A 2 The improvement made due to the disadvantages of high energy consumption and complicated operation of the / O process will reverse the A 2 The combination of / O process and staged water inflow process constitutes deep nitrogen and phosphorus removal

[0006] Although both of the above two patents disclose a combined structure for biological nitrogen and phosphorus removal, neither of them belongs to the staged treatment process, nor can it ensure that the different processes in each stage are in the best state, and there is no independent nitrification and denitrification zone. It cannot provide the best suitable conditions for the nitrification and denitrification reactions, so the removal rate is low and the residence time is long, resulting in an increase in the size of the pool and increasing the construction cost; ~4 times larger internal reflux of nitrifying liquid, not only increases the pool capacity, but also increases the operating cost

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