Device and method for treating urban sewage by using two-stage SPNA denitrification process

Abstract

The invention provides a device and method for treating urban sewage by using a two-stage SPNA denitrification process, aims at the problems of poor denitrification effect, low denitrification load and the like existing in a prior urban sewage SPNA process, and belongs to the field of sewage biological treatment. The method is characterized in that two SPNA reactors are arranged in series. The sewage enters a first-stage SPNA reactor to carry out short-cut nitrification-Anammox reaction to remove 60-80% of ammonia nitrogen in the sewage, subsequently, the effluent from the first-stage SPNA reactor enters a second-stage SPNA reactor via an intermediate water tank. The second-stage SPNA reactor operates under intermittent aeration conditions to further remove residual ammonia nitrogen and complete the denitrification reaction. The two SPNA reactors operate under the conditions of high nitrogen load and intermittent aeration respectively, which is beneficial to inhibiting NOB and enriching Anammox bacteria, the denitrification rate is high, the operation parameters of the two SPNA reactors can be flexibly adjusted according to the quality of inlet water, the quality of outlet water isensured, the method has the advantages of high nitrogen removal rate and good denitrification effect, strong impact load resistance, simple operation and energy saving.

Description

technical field [0001] The invention relates to a device and a method for treating urban sewage by a two-stage SPNA denitrification process, and belongs to the technical field of sewage biological treatment. Background technique [0002] In recent years, with the eutrophication of water bodies caused by excessive discharge of nitrogen and phosphorus in my country, people are paying more and more attention to the treatment of urban sewage. The traditional nitrification-denitrification denitrification process is difficult to achieve deep denitrification, and it is difficult to meet the needs of our country. Increasingly stringent emission requirements. In addition, the traditional nitrification-denitrification process still has problems such as high aeration energy consumption, insufficient carbon source for denitrification, and large excess sludge production. Therefore, the development of energy-saving and efficient biological denitrification process is a research hotspot now...

AI Technical Summary

Problems solved by technology

Among them, one of the main difficulties in the urban sewage SPNA process is to inhibit the growth of nitrite oxidizing bacteria (NOB). Set, compete with Anammox bacteria for nitrite nitrogen substrate, resulting in increased nitrate nitrogen concentration in the effluent and deterioration of denitrification effect

[0005] Although existing data have shown that maintaining a certain amount of residual ammonia nitrogen in the effluent and intermittent aeration can inhibit NOB activity, a certain amount of residual ammonia nitrogen in the effluent will result in poor denitrification effect of the SPNA system; intermittent aeration, that is, aerobic / anoxic Due to the short effective aeration time, the operation mode of oxygen alternation will affect the oxidation of ammonia nitrogen, resulting in a low nitrogen removal load of the system, which is not conducive to the stable and efficient operation of the SPNA system

In addition, the concentration of urban sewage matrix is ​​low, and the growth of Anammox bacteria is slow, so it is difficult to enrich in large quantities in urban sewage treatment systems, which further leads to low nitrogen removal rate and poor denitrification effect in the system.

Images