Improved AAO water treatment system and sewage processing method thereof

Abstract

The invention discloses an improved AAO water treatment system and a sewage processing method thereof. The improved AAO water treatment system comprises an anaerobic reactor, an anoxic reactor, an aerobic reactor, and a settling tank, which are connected in sequence. The aerobic reactor is connected to the anoxic reactor through an inner backflow pipeline. The settling tank is connected to a pre-de-nitrification tank through a sludge outer backflow pipeline. The pre-de-nitrification tank is connected to the anaerobic reactor. The fluid inlet end of the pre-de-nitrification tank is connected toa first branch of a raw sewage inlet pipe, and a second branch of the raw sewage inlet pipe is connected to the anaerobic reactor. Compared with a conventional A2O method, a pre-de-nitrification tankis arranged before an anaerobic tank; the backflow sludge and raw sewage of a settling tank are introduced into the pre-de-nitrification tank; organic substances in the raw sewage are utilized by microbes as a carbon source to carry out de-nitrification; the performance of a conventional AAO system on reducing the influence of backflow nitrate is improved; the bad influence of nitrate nitrogen onanaerobic phosphorus release is eliminated; the phosphorus removing effect is ensured; and the nitrogen removing effect is guaranteed at the same time.

Description

technical field [0001] The invention relates to the field of environmental protection equipment, in particular to an improved AAO water treatment system and a sewage treatment method thereof. Background technique [0002] AAO method, also known as A2O method, is the abbreviation of the first letter of English Anaerobic-Anoxic-Oxic (anaerobic-anoxic-aerobic method). It is a commonly used sewage treatment process and can be used for secondary sewage treatment or tertiary Sewage treatment, as well as reclaimed water reuse, has a good effect of nitrogen and phosphorus removal. [0003] It consists of three processes: [0004] ① Anaerobic reactor: the raw sewage and the phosphorus-containing return sludge discharged from the sedimentation tank enter simultaneously. The main function of this reactor is to release phosphorus, and at the same time, part of the organic matter is ammonified; [0005] ②Anoxic reactor: the primary function is denitrification, nitrate nitrogen is sent ...

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Problems solved by technology

[0008] Disadvantages: However, it is difficult to improve the phosphorus removal effect, and the sludge growth has a certain limit, which is not easy to increase; the denitrification effect is also difficult to further improve; in order to reduce the residence time, prevent the occurrence of anaerobic state and the release of phosphorus from the sludge, enter the sedimentation The treated water in the pool should maintain a certain concentration of dissolved oxygen, but in order to prevent the interference of the circulating mixed solution on the anoxic reactor, the dissolved oxygen concentration should not be too high

[0009] The nitrate nitrogen brought by the returned sludge into the anaerobic zone will also cause insufficient phosphorus release by phosphorus accumulating bacteria (phosphorus release and phosphorus uptake by phosphorus accumulating bacteria are reversible, aerobic phosphorus uptake, anaerobic phosphorus release), and then affect aerobic Phosphorus uptake by the phosphorus accumulating bacteria in the area will ultimately affect the phosphorus removal effect of the system

[0010] From the current operation of the sewage treatment station using the traditional AAO process, it can be seen that the quality of the effluent is unstable, and it is difficult to achieve a good simultaneous denitrification and phosphorus removal effect.

[0011] The reason for these problems is that multifunctional bacterial groups exist in a unified sludge system, and the basic conditions for the survival of various bacteria are quite different.

This difference causes the system to have insufficient supply of the optimal requirements of different bacteria, so each bacteria will compete for survival co-construction and food in order to survive, and this kind of competition just forms the inherent deficiency of the traditional AAO process system

[0012] It is difficult to improve the phosphorus removal effect mainly due to the contradiction between phosphorus accumulating bacteria and denitrifying bacteria, and the contradiction lies in the problem of reaction zone and carbon source

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