CN103663696B - A kind of membrane bioreactor for the treatment of the denitrogenation of preserved szechuan pickle waste water enhanced biological phosphorus removal - Google Patents

Abstract

The invention discloses a membrane bioreactor for treating pickled mustard wastewater to strengthen biological phosphorus and nitrogen removal. It is an integrated reactor composed of A ² /O process, biofilm process and membrane bioreactor. Pool, anoxic pool, aerobic pool, water inlet system, aeration system, drainage system and automatic control equipment. The anaerobic pool, the anoxic pool, and the aerobic pool are all equipped with semi-soft biofilm fillers, and the membrane modules are placed in the aerobic pool without a separate membrane separation area. The reactor uses the sludge on the biological filler in the anaerobic tank for anaerobic phosphorus release and phosphorus accumulation in the aerobic tank to improve the removal rate of total phosphorus in the sewage. Carry out ammoniation; return the nitrifying liquid in the aerobic pool to the anoxic pool, and form denitrification in the anoxic pool. The invention has the advantages of simple structure, high efficiency in treating pollutants, light membrane pollution, and can simultaneously treat pollutants such as organic matter, total nitrogen, total phosphorus, SS and the like in high-salt wastewater.

Description

A Membrane Bioreactor for Enhanced Biological Phosphorus and Nitrogen Removal in Treatment of Pickled Mustard Wastewater

technical field

The invention belongs to the technical fields of sewage treatment and environmental protection, and in particular relates to a membrane bioreactor for intensifying biological phosphorus and nitrogen removal for treating high-salt, high-nitrogen and phosphorus pickled mustard wastewater.

Background technique

With the rapid economic development of the Three Gorges Reservoir area, the production scale of mustard mustard, a pillar industry, is getting larger and larger. During the production process, about 5 million cubic meters of untreated high-salt, high-nitrogen and phosphorus organic matter are discharged into the Three Gorges Reservoir area every year. Wastewater, that is, 22.25 million tons of organic matter (COD), 800,000 tons of nitrogen, and 130,000 tons of phosphorus discharged into the reservoir every year poses a serious threat to the water environment of the Three Gorges Reservoir area. The salinity of waste water produced by mustard industry is as high as 2% to 15%, the concentration of organic pollutants is as high as 3 to 20g/L, the concentration of suspended solids is as high as 7g/L, and it has a high concentration of nitrogen and phosphorus. High-salt mustard mustard wastewater has an inhibitory effect on microbial activity, resulting in poor settling of activated sludge in traditional biological treatment and difficulty in the accumulation of microorganisms in bioreactors. Therefore, it is difficult to treat mustard mustard wastewater with traditional biological treatment. Therefore, the development of a suitable sewage treatment technology for high-salt and high-nitrogen mustard mustard wastewater is of great significance to solve the pollution of mustard mustard sewage discharge in the Three Gorges reservoir area.

Membrane bioreactor (MBR) is a high-efficiency biochemical sewage treatment technology that combines biological treatment technology and membrane high-efficiency filtration technology, also known as membrane separation activated sludge method. Membrane bioreactor has the characteristics of high-efficiency interception, which makes the concentration of suspended solids in the effluent of the system extremely low, and also has the advantage of rapid and efficient removal of pollutants. The implementation of MBR technology in mustard wastewater treatment can make a large number of dominant bacteria and microorganisms accumulate in the reactor without being limited by the influence of salinity, increase the sludge concentration in the system, and make the microorganisms degrade organic matter more thoroughly.

Anaerobic-anoxic-aerobic activated sludge process (A ² /O) is an efficient simultaneous phosphorus and nitrogen removal process, which consists of three pools: anaerobic pool, anoxic pool and aerobic pool. A ² /O has simple structure, short total hydraulic retention time, and simple control operation.

Chinese patent literature (CN102285715A) discloses a composite membrane bioreactor for treating pickled mustard wastewater, which uses a single aerobic biofilm (biological reaction zone) + membrane bioreactor (membrane separation zone) to treat salty Mustard mustard wastewater, although it can effectively degrade organic pollutants, has a low removal rate of total nitrogen (TN) and total phosphorus (TP) for high nitrogen and phosphorus mustard mustard wastewater, and this technology separates the aerobic reaction zone and the membrane separation zone The setting, covering a larger area, increases the aeration volume of the system.

Contents of the invention

The technical problem to be solved by the present invention is to provide a sewage treatment device for treating high-salt, high-nitrogen and phosphorus mustard mustard wastewater, which can reduce the inhibitory effect of wastewater salinity on microorganisms, increase the concentration of sludge in the reactor, and enhance The ability of microorganisms to degrade organic matter can also improve the removal efficiency of TN and TP, and can reduce the occupied area.

In order to solve the above technical problems, the present invention includes sequentially arranged anaerobic pool, anoxic pool and aerobic pool. Connected, the anoxic pool and the aerobic pool are connected through the water inlet hole opened on the partition wall, the nitrifying liquid in the aerobic pool is pumped back to the anoxic pool through the return pump through the return pipe, the anoxic pool has a built-in stirring device, and the aerobic pool The built-in membrane module is connected to the water collection pipe, and the treated sewage is discharged from the water collection pipe. The anaerobic pool, the anoxic pool and the aerobic pool are equipped with semi-soft biofilm fillers.

Due to the combination of anaerobic tank-anoxic tank-aerobic tank and membrane bioreactor, on the one hand, the sludge settling performance in the reactor can not be affected by salinity, and on the other hand, it can overcome the single aerobic biofilm treatment. The disadvantage of low nitrogen and phosphorus removal efficiency in high nitrogen and phosphorus mustard wastewater is to improve the removal efficiency of the system for total nitrogen and total phosphorus. Membrane modules are installed in the aerobic pool, and no separate membrane separation area is set up, which reduces the floor area.

Therefore, the technical effects of the present invention are: the inhibitory effect of wastewater salinity on microorganisms is reduced, the concentration of sludge in the reactor is increased, the degradation ability of microorganisms to organic matter is enhanced, the removal efficiency of TN and TP is improved, and the The occupied area.

Description of drawings

Fig. 1 is a schematic plan view of the present invention;

Fig. 2 is 1-1 sectional view of Fig. 1;

Fig. 3 is a sectional view of line 2-2 in Fig. 1 .

In the figure: 1. Anaerobic tank, 2. Anoxic tank, 3. Aerobic tank, 4. Water inlet pipe, 5 Water inlet hole, 7. Membrane module, 8. Water collection pipe, 9. Return pump, 10. Return pipe , 11. Semi-soft biofilm filler, 12. Agitator, 13. Perforated aeration pipe, 14. Air pump, 15. Suction pump, 16.PLC control box, 19. Valve, 20 partition wall.

detailed description

The present invention will be further described below in conjunction with accompanying drawing.

The idea of the present invention is that an integrated process composed of A ² /O process, biofilm process and membrane bioreactor is used to treat pickled mustard wastewater with high salt and high nitrogen and phosphorus.

As shown in Fig. 1 and Fig. 2, the present invention includes anaerobic pool 1, anoxic pool 2 and aerobic pool 3 arranged in sequence, sewage enters anaerobic pool through water inlet pipe 4, anaerobic pool 1 and anoxic pool 2 pass through The inlet hole 5 provided on the partition wall 20 is connected, the anoxic pool 2 and the aerobic pool 3 are connected through the inlet hole 5 provided on the partition wall 20, and the nitrifying liquid in the aerobic pool 3 passes through the return pump 9 through the return pipe 10 Pumping back to the anoxic pool 2, the anoxic pool 2 has a built-in stirring device 12, and the membrane module 7 built in the aerobic pool 3 is connected to the water collection pipe 8, and the treated sewage is discharged from the water collection pipe 8. Both the oxygen tank 2 and the aerobic tank 3 are provided with semi-soft biofilm fillers 11 .

The reflux ratio of the nitrifying liquid flowing back from the aerobic tank 3 to the anoxic tank 2 is 100%-300%. The above membrane module 7 is a hollow fiber membrane module.

The above-mentioned anaerobic pool 1, anoxic pool 2 and aerobic pool 3 are all equipped with semi-soft biofilm fillers 11, and the density of the film is 30%, 30%, and 40% respectively, which are used to fix the dominant bacterial species in each pool sludge, reducing the sludge return device in the conventional A ² /O process.

The bottom of the aerobic pool 3 is provided with a perforated aeration pipe 13, and the pores are connected with a porous aeration head, and the perforated aeration pipe 13 is connected with an air pump 14 outside the pool to form an aeration system in the pool; the aerobic pool 3 and The membrane modules 7 share a set of aeration system.

As shown in FIG. 3 , valves 19 are respectively provided on the water collection pipes 8 connected to each membrane module 7 . The amount of treated water is controlled by the opening of the valve 19, and the membrane module 7 is connected to the suction pump 15 outside the tank through the water collection pipe 8; Inside the module 7, the treated sewage is discharged from the reactor through the water collecting pipe 8. Suction pump 15 adopts intermittent operation mode, and the pumping and stopping time are controlled by PLC control box 16.

Working process of the present invention is:

Sewage enters the anaerobic tank 1 through the water inlet pipe 4. Under anaerobic conditions, the phosphorus accumulating bacteria release the polyphosphate stored in the body, and actively absorb volatile fatty acids (VFA) at the same time, and use polyhydroxyalkanoate (PHA) The form is stored in the body, so part of the organic matter is removed in the anaerobic pool; the effluent from the anaerobic pool 1 enters the anoxic pool 2 through the water inlet hole 5 on the partition wall 20 between the anaerobic pool 1 and the anoxic pool 2. The denitrifying bacteria use the carbon source provided by the influent as the electron donor and the nitrifying liquid returned by the aerobic tank 3 as the electron acceptor to denitrify, convert nitrate and nitrite into gaseous nitrogen, so as to improve the removal rate of TN Purpose. The anoxic pool 2 communicates with the aerobic pool 3 through the inlet hole 5 opened on the partition wall 20, and the sewage enters the aerobic pool 3 to contact high-concentration aerobic sludge, and most of the organic matter in the sewage is removed. The treated sewage is squeezed into the membrane module 7 under the suction of the suction pump 15, and the membrane module 7 is connected with the water collecting pipe 8 to discharge the sewage out of the system.

Compared with the prior art, the present invention has the following advantages as follows:

1. In the present invention, semi-soft biofilm fillers are placed in the anaerobic tank, anoxic tank and aerobic tank to fix the sludge on the biological filler. The advantages are as follows: First, a large number of dominant bacteria and microorganisms can be gathered in each tank , increase the number of microorganisms in the reactor, and improve the treatment efficiency of pickled mustard wastewater; the second is to slow down the sludge bulking under high-salt conditions; the third is to fix the microorganisms on the biological filler, which can reduce the impact of sludge on membrane module pollution; For the existing A ² /O process tank, the sludge return device can be canceled.

2. The present invention organically combines the A ² /O process with the membrane bioreactor, has the advantages of both processes, and can efficiently treat mustard mustard wastewater with high salt and high nitrogen and phosphorus. On the one hand, the high-efficiency interception effect of the membrane module is used to increase the sludge concentration in the reactor, so that the pollutants can be degraded more thoroughly; at the same time, the complete separation of the hydraulic retention time (HRT) and the sludge retention time (SRT) can improve the system internal The concentration of nitrifying bacteria with a long generation time improves the nitrification efficiency; moreover, the membrane module replaces the secondary settling tank for mud-water separation, which can reduce the influence of salinity on the sludge settling performance. On the other hand, due to the high influent TN of mustard mustard wastewater, the nitrogen removal rate of a single aerobic membrane bioreactor is low. By releasing phosphorus in anaerobic tank and absorbing excessive phosphorus in aerobic tank, the A ² /O process can not only strengthen the removal of phosphorus, but also strengthen denitrification in the anoxic tank by returning the nitrifying liquid in the aerobic tank to the anoxic tank , can greatly improve the removal rate of TN.

3. The present invention inserts the membrane module in the aerobic tank instead of setting up a separate membrane separation area, which can save the floor area of the reactor; at the same time, the aerobic reaction tank and the membrane module share a set of aeration system, which can reduce the amount of aeration , under the action of aeration and scouring, the sludge and organic matter deposited in the membrane pores and on the surface of the membrane can be cleaned, the degree of membrane fouling can be alleviated, and the membrane flux can be maintained at a stable level.

4. The biological fillers in the anaerobic tank, the anoxic tank and the aerobic tank are constantly colliding and rubbing, while the biological fillers in the aerobic zone are also subjected to aeration and scouring to wash away the aged sludge on the filler surface, so that The microorganisms on the biofilm maintain high activity and improve the removal efficiency of microorganisms on pollutants.

Example

The main technical parameters are:

Total nitrogen load: 0.07～0.1kgTN/(kgMLVSS·d)

Running time: the suction pump starts for 9 minutes and stops for 2 minutes

Hanging film density: 30%, 30%, 40% in anaerobic zone, anoxic zone, and aerobic zone, respectively

Dissolved oxygen: <0.5mg/L in anaerobic zone, 0.5-1.0mg/L in anoxic zone, 3-4mg/L in aerobic zone

Average hydraulic retention time: 1.5h in the anaerobic zone, 1.5-2.5h in the anoxic zone, and 8-9h in the aerobic zone

Construction parameters:

Effective water depth: 4 ~ 6m

The volume ratio of anaerobic zone, anoxic zone and aerobic zone is 1:2:5.

In this example, when the hydraulic load is optimal, the removal rates of COD, ammonia nitrogen, TN, soluble phosphate and SS are 91.67%, 90.61%, 68.46%, 40.54% and 98%, respectively, compared with a single aerobic biofilm+ Membrane bioreactor is used to treat salty pickled mustard wastewater, and its removal effect of total nitrogen and total phosphorus is better.

What is used in the present invention is combined semi-soft fiber filler, which is evenly distributed on the periphery of the clinker ring, the tow will not fall off, and at the same time, the phenomenon of agglomeration in the center of the filler is avoided, and the snowflake-like needle-like structure in the middle of the plastic ring is It can also play a good role in water distribution and air distribution, so that the packing has the advantages of good mass transfer effect, no clogging, impact resistance, and stable treatment.

Claims (5)

1. a kind of membrane bioreactor for processing mustard mustard waste water strengthened biological dephosphorization and denitrification, is characterized in that: comprise anaerobic pond (1), anoxic pond (2) and aerobic pond (3) arranged in order, The sewage enters the anaerobic pool (1) through the water inlet pipe (4), and the anaerobic pool (1) communicates with the anoxic pool (2) through the water inlet hole (5) offered on the partition wall (20), and the anoxic pool (2) is connected to the anoxic pool (2). ) is communicated with the aerobic pool (3) through the inlet hole (5) offered on the partition wall (20), and the nitrifying liquid in the aerobic pool (3) is pumped back to the The anoxic pool (2), the anoxic pool (2) has a built-in stirring device (12), the aerobic pool (3) has a built-in membrane module (7), the membrane module (7) is connected with the water collection pipe (8), and the treatment The final sewage is discharged from the water collection pipe (8), and the anaerobic pool (1), the anoxic pool (2) and the aerobic pool (3) are all equipped with semi-soft biofilm fillers (11). 2. according to claim 1, a kind of membrane bioreactor for processing mustard mustard waste water to strengthen biological dephosphorization and denitrification is characterized in that: anaerobic pond (1), anoxic pond (2) and aerobic pond ( 3) The hanging film densities of the medium and semi-soft biofilm fillers (11) are 30%, 30%, and 40%, respectively. 3. A kind of membrane bioreactor for treating mustard mustard wastewater to enhance biological phosphorus and nitrogen removal according to claim 2, characterized in that: the bottom of the aerobic pool (3) is provided with a perforated aeration pipe (13 ), the pore position is connected with the porous aeration head, and the perforated aeration pipe (13) is connected with the air pump (14) outside the pond. 4. A membrane bioreactor for treating pickled mustard wastewater for enhanced biological phosphorus and nitrogen removal according to claim 1, 2 or 3, characterized in that: the water collecting pipe (8) connected to the membrane module (7) is provided with There is a valve (19), and the membrane module (7) is connected with the suction pump (15) outside the tank through the water collection pipe (8). 5. A kind of membrane bioreactor for treating mustard mustard wastewater to strengthen biological phosphorus and nitrogen removal according to claim 4, characterized in that: the volume ratio of the anaerobic pond, the anoxic pond and the aerobic pond is 1 :2:5.