CN202729946U - Two-stage anoxic/oxic (A/O)-membrane biological reactor (MBR) nitrogen and phosphorus removal device - Google Patents

Abstract

The utility model discloses a two-stage A/O-MBR nitrogen and phosphorus removal device. The denitrification and phosphorus removal device includes an anaerobic tank, a first anoxic tank, a first aerobic tank, a second anoxic tank, a second aerobic tank and a membrane tank connected in sequence; the anaerobic tank and the second The anoxic pools are all connected to the water inlet pipes, and the water inlet pipes are provided with water inlet pumps; the membrane modules are arranged in the membrane pools, and the membrane modules are connected to the water outlet pipes, and the water outlet pipes are provided with water outlet pumps; A sedimentation tank is provided at the bottom of the membrane pool, and the sedimentation tank is connected with the anaerobic tank through a sludge mixed liquid return pipe, and a return pump is arranged on the sludge mixed liquid return pipe. The nitrogen and phosphorus removal device can not only remove organic matter, nitrogen, phosphorus and other pollutants in sewage well, but also reduce the energy consumption of MBR process operation, so it is suitable for treating urban domestic sewage.

Description

A two-stage A/O-MBR nitrogen and phosphorus removal device

technical field

The utility model relates to a nitrogen and phosphorus removal device, in particular to a two-stage A/O-MBR nitrogen and phosphorus removal device using a membrane-biological reactor.

Background technique

Urban sewage contains a large amount of nitrogen and phosphorus pollutants. When the sewage is discharged into slow-flowing water bodies such as lakes, reservoirs, estuaries, and bays, nitrogen and phosphorus gradually accumulate, causing aquatic organisms, especially algae, to proliferate, and eventually leading to ecological balance of the water body. severe damage, that is, the occurrence of the so-called eutrophication phenomenon. Eutrophication will not only destroy the original ecosystem of the water body, but also cause significant economic losses to fisheries and aquaculture, and even endanger human health in severe cases. In order to effectively curb the eutrophication of water bodies, more and more countries and regions have formulated strict nitrogen and phosphorus discharge standards. However, due to the contradiction between the demand for carbon sources between denitrification and phosphorus removal in the traditional sewage treatment process, it is difficult to meet the nitrogen and phosphorus concentrations in the effluent at the same time, which makes the denitrification and phosphorus removal of sewage become a hot and difficult point in the field of sewage treatment.

MBR is a new sewage treatment and reuse process that combines membrane separation technology and biological treatment unit. Because the process adopts efficient membrane separation to replace the secondary sedimentation tank in the traditional activated sludge process, the solid-liquid separation efficiency is high, the effluent is good and stable, and can be reused directly; the reactor can maintain a high concentration of microbial biomass and handle volume load High, low floor space; small amount of excess sludge; convenient operation and management, high degree of automation. In view of the advantages of MBR, a considerable scale and number of MBR sewage treatment and recycling projects have been established at home and abroad. Because MBR can operate under high sludge concentration, it can improve the treatment capacity of the system, but too high sludge concentration is not good for membrane fouling control, and high aeration energy consumption is required to control membrane fouling.

Sewage denitrification and phosphorus removal and reduction of system energy consumption are important application fields and development directions of MBR. Due to the complex mechanism and many influencing factors, most of the existing researches independently investigate the denitrification and phosphorus removal or energy saving and consumption reduction of MBR, and it is difficult to balance both. . Some studies use the method of adding an external carbon source to improve the nitrogen and phosphorus removal effect at the same time, but it is not suitable for large-scale promotion due to the increase of process complexity and operating cost. Some studies have used the denitrification and phosphorus removal technology of A ² O process to make denitrification and phosphorus removal share part of the carbon source, which can alleviate the contradiction between the two to a certain extent, but the effect is still limited. The denitrification effect is not ideal. There is also an endogenous denitrification technology that uses the intracellular substances of microorganisms as a carbon source and does not require carbon sources in sewage. Therefore, it is very suitable for the denitrification and phosphorus removal of urban sewage with limited carbon source content. The stability of this technology still needs to be improved. optimization. In terms of energy saving, the goal of saving energy and reducing consumption is mainly achieved by optimizing the structure of membrane modules and developing more efficient aeration methods.

Utility model content

In order to overcome the deficiency that the traditional sewage treatment process cannot effectively remove nitrogen and phosphorus in sewage, the purpose of this utility model is to provide a two-stage A/O-MBR nitrogen and phosphorus removal device. , for low carbon-to-nitrogen ratio sewage, it can perform efficient nitrogen and phosphorus removal treatment without adding additional carbon sources, and the process is simple, the operating energy consumption is lower than that of traditional MBR, and the effluent can meet the national reuse water standard.

A two-stage A/O-MBR denitrification and phosphorus removal device provided by the utility model includes an anaerobic pool, a first anoxic pool, a first aerobic pool, a second anoxic pool, and a second anoxic pool connected in sequence. Oxygen pools and membrane pools;

Both the anaerobic pool and the second anoxic pool are connected with a water inlet pipe, and a water inlet pump is arranged on the water inlet pipe;

The membrane pool is provided with a membrane module, and the membrane module is connected with the outlet pipe, and the outlet pipe is provided with an outlet pump; the bottom of the membrane pool is provided with a sedimentation tank, and the sedimentation tank is refluxed through the sludge mixture. The pipe communicates with the anaerobic tank, and the sludge mixed liquid return pipe is provided with a return pump.

In the above-mentioned two-stage A/O-MBR denitrification and phosphorus removal device, the water inlet pipe is provided with a flow regulating valve to adjust the ratio of entering the anaerobic tank and the second anoxic tank.

In the above-mentioned two-stage A/O-MBR nitrogen and phosphorus removal device, the sedimentation tank may be in the shape of an inverted cone to facilitate the sedimentation of the sludge mixture.

In the above-mentioned two-stage A/O-MBR nitrogen and phosphorus removal device, the anaerobic tank, the first anoxic tank and the second anoxic tank are provided with stirring devices.

In the above-mentioned two-stage A/O-MBR nitrogen and phosphorus removal device, the first aerobic tank, the second aerobic tank and the membrane tank are provided with aeration and oxygenation devices.

In the above-mentioned two-stage A/O-MBR nitrogen and phosphorus removal device, the anaerobic tank, the first anoxic tank, the first aerobic tank, the second anoxic tank, the second aerobic tank and the membrane tank can be formed by Consists of one or more cell pools.

The two-stage A/O-MBR denitrification and phosphorus removal device provided by the utility model has the following advantages: the utility model combines two-stage A/O and MBR, and the traditional MBR process has a good ability to remove ammonia and nitrogen, and can The ammonia nitrogen of the sewage species is completely nitrified, and the two-stage A/O system has a strong denitrification ability. The combination of the two can improve the system’s ability to degrade total nitrogen, which is suitable for the treatment of sewage with a low carbon-to-nitrogen ratio. The system has a strong ability to remove total nitrogen and can To ensure that the total nitrogen in the effluent is obviously superior to other traditional processes; by designing the sedimentation zone in the membrane tank, the sludge concentration of the mixed solution entering the membrane separation zone can be reduced, and the workload of the membrane module can be reduced. Due to the reduction of the sludge concentration in the membrane module area, During operation, the aeration intensity of the membrane module can be appropriately reduced to reduce the operating energy consumption of the MBR system.

Description of drawings

Fig. 1 is a two-stage A/O-MBR nitrogen and phosphorus removal device provided by the utility model.

The marks in the figure are as follows: 1 anaerobic pool, 2 the first anoxic pool, 3 the first aerobic pool, 4 the second anoxic pool, 5 the second aerobic pool, 6 membrane pool, 7 water inlet pipe, 8 water inlet pump , 9 flow regulating valve, 10 membrane module, 11 outlet pipe, 12 sedimentation tank, 13 sludge mixed liquid return pipe, 14 return pump, 15 aeration and oxygenation device, 16 outlet pump.

Detailed ways

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

The two-stage A/O-MBR denitrification and phosphorus removal device provided by the utility model includes an anaerobic pool 1, a first anoxic pool 2, a first aerobic pool 3, a second anoxic pool 4, and a second anoxic pool connected in sequence. Oxygen pool 5 and membrane pool 6; Wherein the anaerobic pool 1 and the second anoxic pool 4 are all communicated with the water inlet pipe 7, and the water inlet pipe 7 is provided with an inlet water pump 8 and a flow regulating valve 9 to regulate the flow into the anaerobic pool 1 and the entering ratio in the second anoxic pool 4; the membrane pool 6 is provided with a membrane module 10, which communicates with the outlet pipe 11, and the outlet pipe 11 is provided with an outlet pump 16 to discharge the purified water The bottom of the membrane pool 6 is provided with an inverted cone-shaped settling tank 12, which can facilitate the settlement of the sludge mixed solution; the settling tank 12 is communicated with the anaerobic tank 1 through the sludge mixed solution return pipe 13, and the sludge mixed solution The return pipe 13 is provided with a return pump 14 for pumping the sludge mixture to the anaerobic tank 1; the anaerobic tank 1, the first anoxic tank 2 and the second anoxic tank 4 are equipped with stirring devices 14. The first aerobic tank 3, the second aerobic tank 5 and the membrane tank 6 are equipped with aeration and oxygenation devices 15.

In the denitrification and dephosphorization device provided by the utility model, the anaerobic pool 1, the first anoxic pool 2, the first aerobic pool 3, the second anoxic pool 4, the second aerobic pool 5 and the membrane pool 6 can be formed by Composed of multiple unit pools.

When the nitrogen and phosphorus removal device provided by the utility model is used for sewage treatment, the process is as follows: the sewage enters the anaerobic pool 1 through the water inlet pump 8, and the organic substrate in the sewage is absorbed by the phosphorus accumulating bacteria and synthesized into PHAs and stored in the cell , and at the same time the phosphorus accumulating bacteria released soluble orthophosphate, which showed that the COD of the supernatant decreased and the phosphorus concentration increased. In the anaerobic tank 1, organic nitrogen is also converted to ammonia nitrogen. Afterwards, the sewage enters the first anoxic tank 2, and the denitrifying bacteria use the sewage carbon source to carry out denitrification and denitrification of the nitrate transported by the sludge mixed liquid return pipe 13 from the sedimentation tank 12. Intracellular PHAs are used for denitrification and phosphorus removal to remove part of nitrate and phosphorus. The sewage then enters the first aerobic pool 3 and the second anoxic pool 7 in sequence. In this technological process, part of the raw water directly enters the second anoxic tank 7 through the raw water distribution pipe 12, and the denitrifying bacteria use the sewage carbon source to denitrify and denitrify the nitrate produced in the first aerobic tank. The sewage is mixed and then flows into the second aerobic zone. At this stage, the phosphorus accumulating bacteria use intracellular PHAs to quickly absorb and remove the dissolved phosphorus, and the COD continues to decrease due to the action of aerobic microorganisms. At the same time, the nitrifying bacteria convert ammonia nitrogen into nitrite Nitrogen and nitrate nitrogen, after the above series of biochemical reactions, the nitrogen, phosphorus and other pollutants in the sewage have been basically removed. Finally, the mixed solution enters the membrane pool 6, where the sludge concentration in the membrane pool 6 is relatively high, and a sedimentation tank 12 is set in the membrane pool 6, and part of the sludge is returned to the front-end process after being concentrated by sedimentation, and the sewage in the membrane pool is reduced through the sludge concentration and backflow. mud concentration, reduce the aeration intensity for controlling membrane pollution, and reduce operating energy consumption; while the membrane pool 6 plays a role in further ensuring water quality, removes suspended pollutants such as colloidal phosphorus through membrane interception and separation, and finally passes through the outlet pump 16 Suction and drainage to obtain effluent that meets national reuse standards.

In the above treatment process, the sewage water quality conditions are: COD content is 200 to 300 mg/L, total nitrogen content is 80 to 100 mg/L, and total phosphorus content is 5 to 10 mg/L. The return ratio of the sludge mixed solution in the sludge mixed solution return pipe can be 200%, the sludge concentration is 5g/L, and the hydraulic retention time is 17 hours. COD in the project water: TN≈3:1, COD content in the effluent is less than 30mg/L, TN content in the effluent is less than 10mg/L, and the final effluent meets the national reuse standard.

The utility model only has one return pipe for the sludge mixed liquid, and the return flow can be adjusted according to the needs. The reflux ratio is generally 100%-400%; the utility model is equipped with two water inlet pipes, that is, two water inlet points, and part of the sewage directly enters the anaerobic pool through the water inlet pipes, and the organic substrate in the water inlet is absorbed and synthesized by phosphorus-accumulating bacteria. Because PHAs are stored in the cells, and phosphorus accumulating bacteria release soluble orthophosphate at the same time, the COD of the supernatant is reduced and the phosphorus concentration is increased; another part of the sewage passes through the diversion pipe of the water inlet pipe and surpasses part of the first anoxic pool and The first aerobic pool directly enters the second anoxic pool to provide a carbon source for denitrification of the nitrate nitrogen produced in the first aerobic pool.

The utility model is equipped with a sedimentation tank in the membrane pool. After the high-concentration activated sludge enters the membrane pool, part of the sludge will sink into the sedimentation tank due to the poor specific gravity of mud and water. The sludge is concentrated and compacted in the funnel-shaped sedimentation tank, which can improve Sludge return efficiency, at the same time, part of the sludge is concentrated and returned to reduce the sludge concentration of the membrane tank. The low sludge concentration in the membrane tank can reduce the potential of membrane fouling, and can also appropriately reduce the intensity of membrane aeration to achieve the purpose of energy saving.

Claims (6)

1. two-stage A/O-MBR denitrification dephosphorization apparatus is characterized in that: described denitrification dephosphorization apparatus comprises anaerobic pond, the first anoxic pond, the first Aerobic Pond, the second anoxic pond, the second Aerobic Pond and the membrane cisterna that is communicated with successively;

Described anaerobic pond and the second anoxic pond all are connected with water inlet pipe, and described water inlet pipe is provided with intake pump;

Be provided with membrane module in the described membrane cisterna, described membrane module is connected with rising pipe, and described rising pipe is provided with out water pump; The bottom of described membrane cisterna is provided with settling tank, and described settling tank is connected with described anaerobic pond by the mud mixed liquid return line, and described mud mixed liquid return line is provided with reflux pump.

2. two-stage A/O-MBR denitrification dephosphorization apparatus according to claim 1, it is characterized in that: described water inlet pipe is provided with flow control valve.

3. two-stage A/O-MBR denitrification dephosphorization apparatus according to claim 1 and 2, it is characterized in that: described settling tank is the back taper bodily form.

4. two-stage A/O-MBR denitrification dephosphorization apparatus according to claim 1 and 2 is characterized in that: be provided with whipping appts in described anaerobic pond, the first anoxic pond and the second anoxic pond.

5. two-stage A/O-MBR denitrification dephosphorization apparatus according to claim 1 and 2 is characterized in that: be provided with aeration oxygenator in described the first Aerobic Pond, the second Aerobic Pond and the membrane cisterna.

6. two-stage A/O-MBR denitrification dephosphorization apparatus according to claim 1 and 2, it is characterized in that: described anaerobic pond, the first anoxic pond, the first Aerobic Pond, the second anoxic pond, the second Aerobic Pond and membrane cisterna form by one or more unit cells.