A2/O-MBR combined process and device for improving low-carbon source town sewage

Abstract

The invention discloses an A2 / O-MBR combined process for improving low-carbon source town sewage and a device thereof. According to the combined process, sewage is treated by an anaerobic tank, a first anoxic tank, a second anoxic tank, an aerobic tank and a membrane tank in sequence and then is discharged; sewage in the second anoxic tank flows back to the anaerobic tank, sewage in the aerobic tank flows back to the first anoxic tank, and sludge in the membrane tank flows back to the anaerobic tank. Aiming at the problems of low nitrogen and phosphorus removal efficiency and matrix competition when the conventional A2 / O process is used for treating low-carbon-nitrogen-ratio town sewage, the anoxic tank is divided into two parts, the reflux of anoxic mixed liquid is increased, the nitrogen removal efficiency is improved by 11.5%, and the phosphorus removal efficiency is improved by 12.2%; according to the process, the average removal rates of COD, ammonia nitrogen, total nitrogen, total phosphorus and SS are 91.7 percent, 98.5 percent, 47.5 percent, 84.2 percent and 98.9 percent respectively; and under the condition that a carbon source is not added, the nitrogen and phosphorus removal effect can be greatly improved.

Description

technical field [0001] The invention belongs to the field of urban sewage treatment, in particular to a low-carbon source urban sewage improvement A 2 / O-MBR combination process and its device. Background technique [0002] In recent years, as pollutant discharge requirements have become more and more stringent, many sewage plants are facing upgrades. A 2 The / O-MBR combination process is widely used in upgrading and upgrading projects of sewage treatment plants due to its advantages of small footprint, high pollutant removal efficiency, good effluent quality, and low residual sludge yield. However, the process itself has two problems. Big problem: One is the contradiction between nitrifying bacteria and phosphorus accumulating bacteria on sludge age. Nitrifying bacteria are autotrophic obligate aerobic bacteria, which are characterized by slow reproduction speed and long generation time. In order to improve the nitrification performance of the system, It is necessary to ...

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Problems solved by technology

A 2 The / O-MBR combination process is widely used in upgrading and upgrading projects of sewage treatment plants due to its advantages of small footprint, high pollutant removal efficiency, good effluent quality, and low residual sludge yield. However, the process itself has two problems. Big problem: One is the contradiction between nitrifying bacteria and phosphorus accumulating bacteria on sludge age. Nitrifying bacteria are autotrophic obligate aerobic bacteria, which are characterized by slow reproduction speed and long generation time. In order to improve the nitrification performance of the system, It is necessary to maintain a long sludge age; phosphorus accumulating bacteria are heterotrophic bacteria with a fast value-added rate, and the removal of phosphorus mainly depends on the discharge of excess sludge. In order to ensure the effect of biological phosphorus removal in the system, it is necessary to maintain a short sludge age

The second is that it is difficult to further improve the efficiency of nitrogen and phosphorus removal. Both denitrifying bacteria and phosphorus accumulating bacteria are heterotrophic functional bacteria and have a high demand for carbon sources. However, the organic matter content in urban sewage in my country is generally low, and the organic matter in the influent water is given priority Utilized by heterotrophic bacteria such as phosphorus accumulating bacteria in the anaerobic tank, it is difficult for the denitrifying bacteria in the anoxic tank to obtain sufficient carbon sources, which in turn affects the denitrification effect of the system

[0003] for A 2 / O-MBR combination process in the treatment of low-carbon urban sewage, Wang Yingying et al. (Wang Yingying, Yu Haiqin, Zhao Gang, et al. Inverted A 2 Study on the nitrogen and phosphorus removal effect of low-carbon source sewage treated by / O-MBR process[J].Water Treatment Technology,2013,39(6):77-79.) using inverted A 2 The / O-MBR process was used to test the nitrogen and phosphorus removal of domestic sewage in a certain town in the north. The results showed that the process's removal effect on nitrogen and phosphorus was still not ideal, and the total nitrogen concentration in the effluent was as high as 25mg·L -1 , the total phosphorus concentration in the effluent is as high as 2.2mg·L -1 , the main reason for this result is that the influent carbon source is insufficient. In order to improve the effect of nitrogen and phosphorus removal, carbon sources are often added to the device, resulting in an increase in operating costs.

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