CN104512963A - Integral multistage simultaneous nitrification and denitrification biological membrane system denitrification method and device - Google Patents

Abstract

An integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification method and device, which belong to the technical field of sewage biological treatment. The device is sequentially composed of a regulation area, a multi-stage simultaneous nitrification and denitrification area, a diversion area and a sedimentation area. made. Among them, the multi-stage simultaneous nitrification and denitrification area is a multi-slot plug-flow type, and each reaction tank is equipped with an aeration system and a segmented water inlet device; the sedimentation area is equipped with an overflow port and a sloping plate sedimentation tank; zone is connected with each reaction tank in the simultaneous nitrification and denitrification zone; the present invention makes full use of the advantages of simultaneous nitrification and denitrification, and concentrates nitrification and denitrification in one reaction zone by controlling operating conditions, without adding additional alkalinity or stirring , nitrification liquid return and sludge return system, energy saving and consumption reduction, at the same time, the multi-stage plug-flow structure enhances the impact load resistance of the system, and the multi-stage water inlet design enhances the denitrification effect of the system, the denitrification and carbon removal effect is stable, and maintenance management convenient.

Description

An integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification method and device

technical field

The invention belongs to the technical field of sewage biological treatment, in particular to an integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification method and device.

Background technique

my country has a large rural population and a large amount of domestic sewage discharge, most of which are directly discharged into water bodies without effective treatment, resulting in serious water environmental pollution problems. Rural villages and market towns are scattered, and it is difficult to centrally transport sewage to sewage treatment plants for treatment; however, sewage treatment systems such as land treatment technology and bio-ecological combination technology that have received widespread attention in China currently occupy a large area and are affected by seasons, regions and other environments. The impact is large, and the treatment effect is unstable. Therefore, the sewage treatment technology with high efficiency, low investment, low operating cost, and simple operation and maintenance is in line with the rural sewage treatment methods and devices to be developed.

As an effective means of rural sewage treatment, integrated sewage treatment equipment has the characteristics of small footprint, quick effect, and convenient operation and management. Aerobic moving bed biofilm system MBBR is a high-efficiency sewage treatment technology. This system is a coexistence system of activated sludge and biofilm. It has large biomass, good denitrification effect, low energy consumption, no clogging, and no backwashing advantages, but the disadvantage is that the filler is easy to lose; the purification tank has the advantages of efficient removal of organic matter and nutrient salts, convenient installation, and simple operation. Its main process is anaerobic filter bed and contact oxidation. If clogging occurs, regular backwashing is required, and the operation is complicated; while the existing AAO and AO biological contact oxidation and denitrification integrated devices are realized through two independent processes of nitrification and denitrification, respectively, by nitrifying bacteria and denitrifying bacteria It is carried out in two different reactors. This process has good nitrogen and phosphorus removal effects and stable operation, but this process needs to be equipped with a separate stirring device; in addition, the purification tank, AAO and AO biological contact oxidation and nitrogen Setting up nitrifying liquid backflow and sludge backflow power devices will increase operation and management costs, and there are certain difficulties in practical application and promotion.

The multi-stage simultaneous nitrification and denitrification (abbreviated as SND) denitrification integrated device of the present invention is a new type of treatment process developed to fully utilize the advantages of simultaneous nitrification and denitrification to solve the problems existing in the existing integrated device. First of all, biological fillers are built in each reaction tank in the simultaneous nitrification and denitrification zone of this process. By controlling the operating conditions, the nitrification and denitrification processes can be realized in the same reaction zone without adding additional alkalinity; secondly, the multi-stage plug-flow design Different loads and environments are formed in each reaction tank, which enhances the system's anti-shock load capacity; at the same time, segmented water intake enhances the denitrification of the system, so that carbon sources can be used efficiently. The total hydraulic retention time of the device is short, the sludge yield is low, and it does not need backwashing, stirring and sludge return equipment. It is economical and practical, and it is an effective device for treating rural domestic sewage.

Contents of the invention

The purpose of the present invention is to provide a new type of integrated device. Aiming at the problems of complex operation and maintenance and high energy consumption in the existing integrated device in the process of rural domestic sewage treatment, a set of new processes and new ideas are provided. It is an economical and efficient device and method for nitrogen and carbon removal.

The multi-stage simultaneous nitrification and denitrification biofilm system integrated denitrification method and device is characterized in that it is constructed based on the integrated coupling of the adjustment area A, the multi-stage simultaneous nitrification and denitrification area B, the diversion area C, and the precipitation area D. The adjustment area A is separated from the multi-stage simultaneous nitrification and denitrification area B by a partition with an orifice on the upper part; the multi-stage simultaneous nitrification and denitrification area B is connected with the precipitation area D through the diversion area C; the multi-stage simultaneous nitrification and denitrification area The nitrification area is divided into 3 tanks, each tank is separated by a baffle with an outlet on the upper part and a reflux port on the lower part, and each tank is equipped with biological filler 9, segmented water inlet pipes and aeration devices; diversion area C and sedimentation The bottom of area D is connected.

The integrated multi-stage simultaneous nitrification and denitrification denitrification method mainly includes the following steps:

(1) The waste water to be treated enters the multi-stage simultaneous nitrification and denitrification denitrification reactor (4) regulation area A with a flow rate Q=33.3～66.7L/h;

(2) The waste water in the adjustment area A first enters into the multi-stage simultaneous nitrification and denitrification area B ₁ reaction tank, the dissolved oxygen DO in the reaction tank is 1.5-3.0 mg/L, and the suspended sludge and filler (9) on the surface of the biofilm Ammonia oxidizing bacteria (AOB bacteria) oxidize NH ₄ ⁺ to NO ₂ ^- , and nitrite oxidizing bacteria (NOB bacteria) further oxidize NO ₂ ^- to NO ₃ ; the interior of the biofilm and the sludge floc in the suspension are anoxic Under certain conditions, denitrifying bacteria use NO ₃ ^- as the electron acceptor and COD as the electron donor to carry out partial denitrification denitrification. In addition, aerobic denitrification on the surface of the biofilm and in the suspension also has a metabolic effect on COD. This stage mainly completes Nitrification and partial denitrification of ammonia nitrogen;

(3) The mixed solution treated in the _B1 reaction tank enters the _B2 reaction tank under the thrust of the water flow, and at the same time enters the _B2 reaction tank as well as the raw water flowing in through the segmented water inlet pipe (1). The DO is controlled at 1.0-2.0 mg/L, and the raw water and the nitrifying liquid flowing from the _B1 reaction tank are fully nitrified and denitrified in this tank.

(4) The mixed liquid treated in the _B2 reaction tank and the raw water entered by the segmented water inlet pipe (1) enter the _B3 reaction tank at the same time for final nitrification and denitrification. The DO of the reaction tank is controlled at 0.5~1.5mg/L ; The total hydraulic retention time of the multi-stage simultaneous nitrification and denitrification zone is 6.0-12.0h;

(5) The mixed solution treated in the multi-stage simultaneous nitrification and denitrification zone _B3 reaction tank enters the precipitation zone D through the diversion zone C;

(6) The mixed liquid is separated from mud and water in the sedimentation area D. The sedimentation time is 1.5 to 3.0 hours. The supernatant is discharged through the overflow port, and the sinking activated sludge slides to the return port at the bottom of the diversion area through the inclined plate. _B3 The gas-water mixed flow generated by the aeration of the reaction tank is returned to the multi-stage simultaneous nitrification and denitrification zone, and the size of the sludge return port (11) is adjusted by adjusting the height of the sludge return adjustable baffle, and finally, the mechanical sludge discharge method is used Regularly remove the remaining sludge in the sedimentation tank.

(7) Segmented water intake stage: Under the suction of the water intake pump, the wastewater in the adjustment area (A) enters the bottom of the reaction tanks of the simultaneous nitrification and denitrification areas B ₁ , B ₂ , and B ₃ through the segmental intake pipe (1), and passes through The regulating valve (3) controls the influent flow rate of each reaction tank, and controls the distribution ratio of different influent flow rates. The flow distribution ratios corresponding to B ₁ , B ₂ , and B ₃ are Q ₁ : Q ₂ : Q ₃ =3:2 :1 and 3:(3‐4):3. This stage is mainly to improve the denitrification and nitrogen removal efficiency of the system.

In the present invention, the adjustment of the size of the sludge return port (11), the arrangement of fillers, and the adjustment of the distribution ratio of different inflow flows are to correspond to different inflows but only need to meet the requirements of the outflow.

Compared with the existing integrated device of the present invention, the design of the reaction device has the following advantages:

(1) Integrated multi-stage simultaneous nitrification and denitrification biofilm denitrification device, easy to operate and manage, hygienic and environmentally friendly;

(2) The reasonable division of the multi-stage simultaneous nitrification and denitrification zone creates a push-flow state in the reaction zone, improves the reaction rate, and increases the impact load resistance;

(3) The present invention enables nitrification and denitrification to be carried out in the same reactor, without additional carbon source and alkalinity, without stirring and nitrification night reflux equipment, saving resources;

(4) In the present invention, since the reflux port is set at the lower part of each partition in the B area, the reflux of the sludge can be realized by using the aeration effect, and there is no need to separately set up a sludge reflux system, which saves equipment cost and operation and processing costs;

(5) In the multi-stage simultaneous nitrification and denitrification area, due to the setting of hydrophilic biological fillers, the biomass is large, the treatment efficiency is high, and backwashing is not required. By reasonably controlling the DO concentration of each aeration reaction tank, the denitrification effect of the system can be optimized. Stable treatment effect, energy saving and consumption reduction;

(6) The multi-stage water inlet setting reduces the loss of COD in the system, makes full use of the carbon source involved in denitrification and denitrification, and improves the efficiency of denitrification;

(7) The high biomass in the device shortens the hydraulic retention time, the sludge yield is low, and the infrastructure cost and operating cost are saved;

(8) Integrated construction, convenient operation and management, and conducive to the promotion and application of actual projects.

Description of drawings

Fig. 1 is a schematic diagram of an integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification device provided by the present invention.

In the figure: 1-segmented water inlet pipe; 2-water inlet pump; 3-regulating valve; 4-multi-stage simultaneous nitrification and denitrification denitrification reactor; 5-gas pump; 6-gas flow meter; 7-gas pipeline; 8- Aeration head; 9-filler; 10-outflow port; 11-return port; 12-adjustable baffle for sludge return; 13-slope sedimentation tank; A-regulation area; B-multi-stage simultaneous nitrification and denitrification area ; C- diversion area; D- precipitation area.

Detailed ways

The application will be further described below in conjunction with the accompanying drawings and embodiments.

The device is shown in Figure 1. An integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification device provided by the present invention is mainly composed of segmented water inlet pipe 1, water inlet pump 2, regulating valve 3, multi-stage simultaneous nitrification Nitrification and denitrification reactor 4, air pump 5, gas flow meter 6, gas delivery pipe 7, aeration head 8, filler 9, outflow port 10, return port 11, sludge return adjustable baffle plate 12, inclined plate sedimentation tank 13 ; Among them, the multi-stage simultaneous nitrification and denitrification denitrification reactor 4 is sequentially constructed from the adjustment area A, the multi-stage simultaneous nitrification and denitrification area B, the diversion area C, and the precipitation area D from left to right; the segmented water inlet pipe 1 Set at the bottom of the regulating tank, the multi-stage simultaneous nitrification and denitrification area is composed of three reaction tanks to form a multi-stage series structure, and the two adjacent reaction tanks are separated by a partition with an outlet port 10 on the upper part and a return port 11 on the lower part , wherein the size of the backflow port can be adjusted by an adjustable movable baffle 12, the volume ratio of each reaction tank is 1:1:1, and each reaction tank is equipped with an aeration head 8 and a filler 9, wherein the filling rate of the filler The dissolved oxygen concentration in the three tanks is controlled at 1.5-3.0mg/L, 1.0-2.0mg/L, 0.5-1.5mg/L, and the total hydraulic retention time is 6.0 ~12.0h; the height of the sludge return port is H ₁ = 5cm, H ₂ = 10cm and H ₃ = 15cm; the segmental inflow flow distribution ratio is Q ₁ : Q ₂ : Q ₃ = 3:2:1, and 3:( 3-4): 3; Segmented water inlet pipe 1 is connected with water inlet pump 2 and regulating valve 3 respectively; air pump 5, gas flow meter 6, air pipe 7, and aeration head 8 are connected in sequence; inclined plate 14, overflow port 15 They are all arranged in the precipitation area D, and the angle between the inclined plate 14 and the horizontal is 45°-60°.

Using this device to achieve the purpose of simultaneous nitrification and denitrification denitrification, the specific process is as follows:

Step 1: Start the film formation in the multi-stage simultaneous nitrification and denitrification zone.

Firstly, the activated sludge was inoculated on the biophoretic filler. The sludge was taken from the return sludge of the sewage treatment plant. The MLSS of the inoculated sludge was 3000mg/L. Finally, the reactor adopts the method of "supplementing raw water - 18 hours of stuffy exposure - 4 hours of static sedimentation - quickly removing the supernatant - replenishing raw water". After repeating 4 cycles, the reactor is continuously fed with water, and the film is hanged by a dynamic natural culture method. And gradually increase the influent load according to the treatment effect until the design flow rate. When the COD removal rate is >80%, and the NH ₄ ⁺ ‐N removal rate is >85%, it indicates that the biofilm formation is basically completed.

Step 2: The formal operation of the integrated multi-stage simultaneous nitrification and denitrification device.

After successful film formation, the reactor enters the formal operation stage. The waste water entering the conditioning area enters the reaction tanks of the multi-stage simultaneous nitrification and denitrification area B under the action of the water pump with a flow rate of Q=33.3~66.7L/h through the segmented water inlet pipes, and the mixed liquid in the reaction tank _B1 Under the thrust of the water flow, it enters the reaction tanks B ₂ and B ₃ in turn, and the mixed liquid after the final treatment in the B ₃ reaction tank enters the sedimentation area through the diversion area; The sinking activated sludge slides through the inclined plate to the return port at the bottom of the diversion area, and returns to the multi-stage simultaneous nitrification and denitrification area under the action of the gas-water mixed flow generated by the aeration of the _B3 reaction tank.

The raw water is taken from the supernatant of the septic tank in the teaching and staff living quarters in the west area of Beijing University of Technology. The water quality characteristics are shown in the table below:

Test conditions: the water inlet pump controls the inlet water flow rate Q=50L/h, the total HRT of the multi-stage simultaneous nitrification and denitrification zone=8h, and the three sets of gas flow meters respectively control the B ₁ reaction tank DO ₁ =1.5～3.0mg/L, B ₂ Reaction tank DO ₂ =1.0～2.0mg/L, B ₃ reaction tank DO ₃ =0.5～1.5mg/L, settling time is 2h, MLSS is between 2800～5000mg/L, the treatment effects of each test stage are as follows: (Note : average value in brackets)

It can be seen from the above table: at each test stage, the effluent COD<50mg/L, the height of the sludge return port is 15cm, and the influent flow ratio is 3:4:3 and 1:1:1, NH ₄ ⁺ -N<5mg/L L, all reached the first-level A standard; the process is set up in stages, and under the condition that the average carbon-nitrogen ratio of the influent is only 3.5, it still achieves a high TN removal rate and improves the carbon source utilization rate of the system.

The above are five embodiments of the present invention, and the implementation of the present invention is not limited thereto.

Claims (2)

1. An integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification device, characterized in that: It includes: segmented water inlet pipe (1), water inlet pump (2), regulating valve (3), multi-stage simultaneous nitrification and denitrification denitrification reactor (4), air pump (5), gas flow meter (6), transmission Air pipe (7), aeration head (8), filler (9), outflow port (10), return port (11), sludge return adjustable baffle (12), inclined plate sedimentation tank (13); The multi-stage simultaneous nitrification and denitrification denitrification reactor is sequentially constructed from the adjustment area A, the multi-stage simultaneous nitrification and denitrification area B, the diversion area C, and the precipitation area D from left to right; the adjustment area A and the multi-stage simultaneous nitrification The denitrification area B is separated by a partition with an orifice on the upper part; the multi-stage simultaneous nitrification and denitrification area is equidistantly equipped with three reaction tanks B ₁ , B ₂ , and B ₃ , and the two adjacent reaction tanks are equipped with an upper part. The outlet (10) is separated from the partition with the backflow port (11) at the lower part, and the bottom of the three reaction tanks B ₁ , B ₂ , and B ₃ are all equipped with aeration devices and hydrophilic polyacrylic acid Fibrous filler (9), each reaction tank is provided with segmented water inlet pipes; the diversion area C and the sedimentation area D are separated by a baffle plate with a closed upper end and a lower end connected, and the sedimentation area D is provided with a 45-degree inclined plate (14 ), and overflow port (15). 2. the method for applying the integrated multi-stage simultaneous nitrification and denitrification biofilm system denitrification device according to claim 1, is characterized in that: (1) Wastewater to be treated enters the adjustment zone A of the multistage simultaneous nitrification and denitrification denitrification reactor; (2) The wastewater flowing out from the regulation area A first enters the multi-stage simultaneous nitrification and denitrification area B ₁ reaction tank, under the action of aeration, fully contacts with the activated sludge and the biofilm on the filler (9), under the action of water flow thrust The bottom flows into the B ₂ and B ₃ reaction tanks sequentially through the upper outlet (10), and the sludge concentration in the multi-stage simultaneous nitrification and denitrification zone is 2800-6000mg/L; the height of the adjustable baffle (12) can be adjusted by adjusting the sludge return flow The size of the return port (11) is adjusted by means of the method; the operation of the method of gradually decreasing aeration is adopted, and the dissolved oxygen DO of the three tanks is controlled at 1.5-3.0mg/L, 1.0-2.0mg/L, 0.5-1.5mg/L respectively; The total hydraulic retention time of simultaneous nitrification and denitrification zone B is 6.0-12.0h; (3) The mixed solution that has been fully treated in the multi-stage simultaneous nitrification and denitrification zone enters the precipitation zone D through the diversion zone C; (4) The mixed liquid is separated from mud and water in the sedimentation zone D, the sedimentation time is 1.5~3.0h, the supernatant is discharged through the overflow port (15), and the activated sludge slides to the diversion through the inclined plate (14) under the action of gravity At the return port (11) at the bottom of zone C, under the action of the gas-water mixed flow generated by the aeration of the _B3 reaction tank, it first returns to the multi-stage simultaneous nitrification and denitrification zone _B3 reaction tank, and then passes through the sludge return port between the tanks ( 11) Return to the B ₂ and B ₁ reaction tanks to achieve the purpose of sludge return; use the mechanical sludge discharge method to regularly remove the remaining activated sludge in the sedimentation tank; (5) Segmented water intake stage: the water inlet pipe is set at the bottom of the adjustment area, and under the suction of the water inlet pump, the waste water enters the simultaneous nitrification and denitrification zone B ₁ , B ₂ , and B ₃ reaction tanks through the segmented water intake pipe (1) At the bottom, each outlet pipe section is provided with a regulating valve (3), through which the influent flow of each reaction tank is controlled, and the flow distribution ratios corresponding to B ₁ , B ₂ , and B ₃ are Q ₁ : Q ₂ : Q ₃ = 3:2:1 and 3:(3-4):3.