CN111908735A

CN111908735A - AAO process transformation method for urban sewage treatment plant based on anaerobic ammonia oxidation

Info

Publication number: CN111908735A
Application number: CN202010888456.1A
Authority: CN
Inventors: 张文杰; 刘小宁; 韦愿; 金樾
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2020-11-10

Abstract

The invention discloses an AAO process modification method of an urban sewage treatment plant based on anaerobic ammonia oxidation. On the basis of the traditional AAO process, anaerobic ammonia oxidizing bacteria are added into an anoxic reactor. Anaerobic ammonium oxidation bacteria and denitrifying bacteria coexist in the anoxic reactor, the dissolved oxygen of the anoxic reactor is strictly controlled to be 0.3 +/-1 mg/L, the efficient and rapid denitrification of the sewage is realized through the reaction of the microorganisms, and the reaction energy consumption is saved. After releasing phosphorus by the anaerobic reactor, the sewage overflows to the anoxic reactor for denitrification, then the phosphorus is removed by the aerobic reactor, and finally the sewage is precipitated in a sedimentation tank and then is discharged. And returning the precipitated sludge to the anaerobic reactor, and returning the turn liquid in the aerobic tank to the anoxic reactor, so that the transformation of the AAO process of the urban sewage treatment plant based on anaerobic ammonia oxidation is realized. The invention has good denitrification performance, saves energy consumption and effectively solves the problems of insufficient flora and limited efficiency of the denitrification efficiency of the AAO process.

Description

AAO process transformation method for urban sewage treatment plant based on anaerobic ammonia oxidation

Technical Field

The invention belongs to the technical field of anaerobic ammonia oxidation in sewage treatment in environmental engineering, and particularly relates to an AAO process modification method for an urban sewage treatment plant based on anaerobic ammonia oxidation.

Background

With the aggravation of water pollution degree and the implementation of more and more strict sewage discharge standards, the state continues to produce water treatment new administration, and the newly issued ten items of water definitely require that urban sewage treatment facilities in sensitive areas after 2018 comprehensively reach the first-class A discharge standard of pollutant discharge Standard of urban sewage treatment plants (GB 18918-2002), so that the requirements of the sewage treatment plants on removing nitrogen, phosphorus, organic pollutants and the like are higher and higher. To simultaneously realize the purposes of nitrogen and phosphorus removal and organic pollutant removal, anaerobic, anoxic, aerobic and other conditions need to be created in space and time in the reactor. Among the processes currently developed and applied are Anaerobic/Anoxic/aerobic (AAO) processes, sequencing batch bioreactors (SBR) and variants thereof, oxidation ditch processes, dual cycle two-phase biological treatment processes (BICT), Anaerobic/Anoxic and nitrification (AAN) processes, and the like. The AAO process can synchronously remove COD (chemical oxygen demand) and nitrogen and phosphorus in sewage through different reaction conditions and operation variables, can realize multi-mode flexible switching according to seasonal changes, discharge requirements, inflow water quality and the like, and can realize water quality improvement and running cost reduction. However, the AAO process is not sufficient in the denitrification and dephosphorization flora because the applicable method is a simple activated sludge method and the denitrification and dephosphorization bacteria are difficult to enrich in large quantities and fix in different zones. Therefore, the AAO process in the prior art is limited by the system, so that the nitrogen and phosphorus removal efficiency is limited.

Heterotrophic denitrification is considered to be the only biological process of natural nitrogen generation in the conventional nitrogen cycle theory, and the discovery of anaerobic ammonia oxidation in a novel nitrogen cycle has changed this recognition. Anammox (Anammox) refers to the anaerobic ammonia oxidation of bacteria with Nitrite (NO) under anoxic conditions₂ ^-) Introduction of ammonia (NH) as an electron acceptor₄ ⁺) Direct oxidation to nitrogen (N)₂) The biological process of (1). Has the advantages of no need of additional carbon source substances, high load, low residual sludge yield and the like, and has wide application prospect in the field of sewage denitrification. In consideration of the respective characteristics of the two processes, the AAO process can be modified by adding an anaerobic ammonia oxidation process into the AAO processThe process improves the quality of the effluent.

Disclosure of Invention

The invention aims to provide an AAO process modification method of an urban sewage treatment plant based on anammox, which reduces reaction energy consumption and improves effluent quality through the effect of anammox.

The method comprises the following specific steps:

an AAO process coupled anaerobic ammonia oxidation reaction device is arranged to inoculate activated sludge of a sewage treatment plant. The device comprises a water inlet barrel, an anaerobic reactor, an anoxic reactor, an aerobic reactor and a sedimentation tank. The anaerobic reactor is filled with water from the bottom, a heat-preservation interlayer is arranged outside the anaerobic reactor, and a stirrer is arranged in the anaerobic reactor; the anoxic reactor is provided with a pH on-line detection system, a stirrer and a heating system; the aerobic reactor is internally provided with a heating system, a stirrer and an aeration system. Wherein anaerobic ammonia oxidizing bacteria are added into the anaerobic reactor, so that the anaerobic reactor comprises anaerobic ammonia oxidizing bacteria and denitrifying bacteria. The inlet water enters from the lower part of the anaerobic reactor through the water inlet pump, after being fully stirred by the stirrer of the anaerobic reactor, the outlet water flows into the anoxic tank by utilizing the height difference between the reactors, the stirrer in the anoxic reactor continuously stirs to ensure that DO is controlled to be 0.3 +/-1 mg/L, and the pH value in the reactor is controlled by the pH on-line monitoring system to be 7.5 +/-1. The sewage after the anaerobic ammonia oxidation and denitrification bacteria reaction enters an aerobic reactor, a stirrer in the aerobic reactor continuously works to fully contact the sewage with microorganisms, an air blower controls an aeration sand head to aerate the reactor, and DO is controlled to be 3 +/-1 mg/L. Part of water treated by the aerobic reactor flows back to the anaerobic reactor in a form of backflow water under the action of a backflow pump, and is converged with inlet water at the bottom of the anaerobic reactor; and water overflowing from the aerobic reactor enters a sedimentation tank through an overflow pipe, a liquid level controller is arranged in the sedimentation tank to control the liquid level height in the reactor, the settled sludge is pumped into the anaerobic reactor through a sludge reflux pump, and the settled effluent reaching the standard is discharged out of the sedimentation tank. Controlling DO in the anaerobic reactor to be less than 0.1 mg/L, and controlling the temperature between the three reactors to be 25 +/-1 ℃ through the heat-preservation interlayer and the heating system. Therefore, the transformation method of the AAO process of the urban sewage treatment plant based on the anaerobic ammonia oxidation can be realized.

The invention has the beneficial effects that:

the invention has good denitrification performance and solves the problem of high running energy consumption of the AAO process by the transformation method of the AAO process of the urban sewage treatment plant based on the anaerobic ammonia oxidation. The improvement method can ensure the biomass in the reactor, and the microorganisms in each stage can fully exert the advantages and functions thereof, thereby optimizing the AAO process of the common urban sewage treatment plant.

Drawings

FIG. 1 is a schematic diagram of a reaction apparatus for coupling AAO process with anammox in the present invention.

FIG. 2 is a process flow diagram of an AAO process in a sewage treatment plant.

The labels in the figure are: r1-anaerobic reactor; r2-anoxic reactor; r3-aerobic reactor; r4-sedimentation tank; 1-a water inlet barrel; 2-heat preservation interlayer; 3-water inlet of anaerobic reactor; 4-a stirrer; 5-water outlet of the anaerobic reactor; 6-sampling port of anaerobic reactor; 7-water inlet of anoxic reactor; 8-pH probe; 9-online pH monitor; 10-temperature controller; 11-a heating rod; 12-a water outlet of the anoxic reactor; 13-the water inlet of the aerobic reactor; 14-an aerated sand head; 15-a blower; 16-an aerobic reactor water outlet; 17-a water inlet of the sedimentation tank; 18-a water outlet of the sedimentation tank; 19-a liquid level controller; p1-water inlet pump; p2-sludge recirculation pump; P3-Mixed liquor reflux pump.

Detailed Description

Example (b):

in order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a reaction apparatus for coupling AAO process with anammox in the present invention. The device comprises a water inlet tank 1, an anaerobic reactor R1, an anoxic reactor R2, an aerobic reactor R3 and a sedimentation tank R4. Sewage enters an anaerobic reactor R1 through a water inlet pump P1, a stirrer is arranged in the anaerobic reactor R1, and the sewage and activated sludge are continuously stirred to be fully contacted for reaction so as to fully release phosphorus in the sewage. The effluent of the anaerobic reactor R1 overflows from a water outlet 5 of the anaerobic reactor into a water inlet 7 of the anaerobic reactor through the action of gravity, and a pH online monitoring system, a stirrer and a heating system are arranged in the anaerobic reactor R2. Anaerobic ammonia oxidizing bacteria are added into the anoxic reactor R2 according to a certain proportion, so anaerobic ammonia oxidizing bacteria and denitrifying bacteria coexist in the reactor for denitrification. The denitrified sewage overflows to the water inlet 13 of the aerobic reactor from the water outlet 12 of the anoxic reactor, and the aerobic reactor R3 is provided with an aeration sand head 14 and a blower 15, and continuously aerates the section reactor to achieve the effect of dephosphorization. The sewage after denitrification and dephosphorization enters a sedimentation tank R4 for sludge sedimentation, and the settled effluent is discharged out of the reactor through a water outlet 18 of the sedimentation tank. Part of mixed liquor in the aerobic reactor R3 flows back to the anoxic reactor R2 through the mixed liquor reflux pump P3, part of the precipitated sludge is discharged out of the reactor, and the other part of the precipitated sludge flows back to the anaerobic reactor R1 through the sludge reflux pump P2. The transformation of the AAO process of the urban sewage treatment plant based on the anaerobic ammonia oxidation can be realized through the reaction.

In the modified AAO process, pH online adjusting systems 8 and 9 adjust the pH value of an anoxic reactor R2 by adding acid liquor, so that the pH value is kept at 7.5 +/-1, and effluent of each reactor overflows to a reactor at the next stage under the action of gravity. The stirrer 4 continuously stirs three groups of reactors R1, R2 and R3 to ensure that microorganisms in the sludge are fully contacted with the sewage, the aeration systems 14 and 15 provide dissolved oxygen for the aerobic reactor R3 to ensure that the dissolved oxygen of the aerobic reactor is controlled to be 3 +/-1 mg/L during the operation, the dissolved oxygen is controlled to be less than 0.1 mg/L during the operation of the anaerobic reactor R1, the dissolved oxygen of the anoxic reactor R2 is controlled to be 0.3 +/-1 mg/L during the operation, and the temperature in the three reactors is controlled to be 25 +/-1 ℃.

The anaerobic reactor R2 mainly contains denitrifying bacteria and added anaerobic ammonium oxidation bacteria, sewage after reaction in the anaerobic reactor R1 enters the anaerobic reactor R2 containing anaerobic ammonium oxidation bacteria, and through the combined action of anaerobic ammonium oxidation and denitrification, the sewage can be denitrified more quickly and efficiently, the operation energy consumption is saved, and the biomass of sludge in the reactor can be ensured.

The transformation method of the AAO process of the urban sewage treatment plant based on the anaerobic ammonia oxidation is shown in figure 2: anaerobic ammonium oxidation bacteria with denitrification function are added into the anoxic reactor R2, and the rapid and efficient denitrification is carried out in the anaerobic ammonium oxidation bacteria and the denitrification bacteria in the stage. The denitrification method based on the anaerobic ammonia oxidation reforms the AAO process, improves water quality, reduces energy consumption for operation and use, and successfully achieves the reforming of the AAO process of the urban sewage treatment plant based on the anaerobic ammonia oxidation.

The foregoing shows and describes embodiments and the general principles of the present invention, and is not intended to limit the scope of the invention. Any changes in shape or configuration made in accordance with the present invention are intended to fall within the scope of the claimed invention without departing from the spirit and scope thereof.

Claims

1. An AAO process modification method of a town sewage treatment plant based on anaerobic ammonia oxidation is characterized by comprising the following specific steps:

setting a reaction device for coupling an AAO process with anaerobic ammonia oxidation, wherein the reaction device comprises a water inlet barrel, an anaerobic reactor, an anoxic reactor, an aerobic reactor and a sedimentation tank; the anaerobic reactor is internally provided with a stirrer, and the outside of the anaerobic reactor is provided with a heat-preservation interlayer; the anoxic reactor is internally provided with a pH on-line adjustment monitor, a heating device and a stirrer; the aerobic reactor is internally provided with an aeration system to provide sufficient dissolved oxygen for microorganisms to achieve the effect of dephosphorization; the effluent water of each stage flows into the reactor of the next stage through the height difference existing among the reactors; the pH on-line adjustment monitor automatically adds acid liquor to keep the pH value in the reactor stable, the aeration device provides dissolved oxygen for the reactor, and the stirrer enables microorganisms to be fully mixed with sewage; anaerobic ammonium oxidation bacteria are added in the anoxic reactor, so that the microorganisms existing simultaneously comprise denitrifying bacteria and anaerobic ammonium oxidation bacteria; anaerobic ammonium oxidation bacteria with a denitrification function are added into the anoxic reactor R2, and rapid and efficient denitrification is carried out in the stage by utilizing the action of the anaerobic ammonium oxidation bacteria and the denitrifying bacteria, so that the AAO process improvement of the urban sewage treatment plant based on the anaerobic ammonium oxidation is realized;

the anaerobic reactor, the anoxic reactor and the aerobic reactor fully mix sewage and microorganisms through the stirrer, the aeration system provides dissolved oxygen for the aerobic reactor, so that the dissolved oxygen during the operation of the aerobic reactor is controlled to be 3 +/-1 mg/L, the dissolved oxygen during the operation of the anaerobic reactor is less than 0.1 mg/L, and the dissolved oxygen of the anoxic reactor is controlled to be 0.3 +/-1 mg/L; the pH value of the anoxic reactor is adjusted to 7.5 +/-1 by a pH on-line monitoring system.