Ferroelectric electrode coupled anaerobic granular sludge membrane bioreactor

Abstract

The application discloses an iron electrode coupled anaerobic granular sludge membrane bioreactor, which comprises a reactor body, a granular sludge bed and a clarified liquid are sequentially arranged in the reactor body from bottom to top, an iron negative electrode and a metal mesh positive electrode are oppositely arranged in the clarified liquid, and a water outlet pipe is communicated with the side wall of the reactor body corresponding to the clarified liquid. 2+ , Fe 2+ has a strong flocculation effect, reduces the content of suspended sludge in the clarified liquid, the released divalent iron can connect various anions such as hydroxyl, acid radical, sulfate radical and phosphate radical ion to form large flocculation sludge, reduces soluble protein and polysaccharide and is converted into solidified extracellular polymer, reduces pore size blockage and reduces the formation of high-strength attached sludge cake layer, and therefore irreversible membrane pollution is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment equipment, and particularly relates to an iron electrode coupled anaerobic granular sludge membrane bioreactor. BACKGROUND

[0002] At present, the traditional activated sludge method is adopted in the municipal sewage treatment process, and the traditional process occupies a large area and consumes a large amount of energy for aeration, and a large amount of carbon dioxide is discharged to intensify the greenhouse effect, and a large amount of chemical agents need to be added, which is a low resource recycling process. With the population growth, the discharge amount of municipal sewage is increasing year by year. Since municipal sewage is an important renewable resource, the new concept of municipal sewage treatment is gradually changing from pollutant removal to sewage resourceization, and resources and energy are recovered from sewage, which is an important means to solve the urban water crisis and energy shortage. The anaerobic membrane bioreactor is a new type of high-efficiency sewage treatment energy recovery technology, which combines the anaerobic methane energy recovery technology and the membrane separation technology, and has the characteristics of good effluent water quality and high-efficiency interception of methanogenic bacteria. The anaerobic membrane bioreactor for treating municipal sewage still has technical bottlenecks, mainly because the COD concentration of the influent is low, so the microbial activity is low, the energy recovery efficiency is low, in addition, the anaerobic membrane is seriously polluted, the effluent flux is small, the membrane pollution energy consumption is high, frequent chemical cleaning is needed, and the membrane service life is short. The built-in anaerobic granular sludge membrane bioreactor has the advantages of high load, small energy consumption and small area compared with other traditional anaerobic membrane bioreactors. However, for the built-in anaerobic granular sludge membrane bioreactor, due to the introduction of the membrane, the flocculent sludge cannot be selectively washed out and stays in the reactor to compete with the granular sludge for the limited COD (the COD concentration of the municipal sewage is low, 100-200 mg / L, and the organic load is also low), thereby affecting the growth of the anaerobic granular sludge, and even causing the particle size of the granular sludge to become small, the settling performance of the granular sludge bed to become poor, and finally affecting the treatment effect. In addition, due to the poor settling performance of the granular sludge bed, the nature of the sludge supernatant will also become poor, the total suspended solids concentration increases, the flocculent sludge accumulates, the soluble microbial products (SMP) and extracellular polymeric substances (EPS) increase, and rapid membrane pollution is caused.

[0003] Since the sewage has a strong impact shear force upward after entering, the accumulated sludge bed and granular sludge are easily dispersed, and then the dispersed part of the granular sludge and microorganisms float up with the clear water, not only losing the microorganisms, but also losing the degradation efficiency of the dispersed microorganisms and granular sludge. The dispersed sludge is easy to be adsorbed on the hollow fiber membrane to reduce the membrane flux. Therefore, the present application mainly solves the problems that the granular sludge is unstable, and the impact water flow exists from bottom to top in the reactor, which causes the granular sludge to be easily dispersed and the activity to be reduced. SUMMARY

[0004] The purpose of the present application is to provide an iron electrode coupled anaerobic granular sludge membrane bioreactor, which can strengthen the treatment of municipal sewage treatment system, the electric field of the system can promote anaerobic digestion to improve the removal efficiency and methane production, and can maintain the stability of the system under adverse conditions such as low temperature and low load, and the electric field can slow down the membrane pollution, the iron release of the electric field can help to promote the growth and enrichment of methanogenic bacteria, help to maintain the granulation of granular sludge, thereby maintaining the treatment effect and methane production of the system, and slowing down the membrane pollution.

[0005] To solve the above technical problems, the present application is realized by the following technical scheme:

[0006] An iron electrode coupled anaerobic granular sludge membrane bioreactor, comprising a reactor body, a sewage pipe is communicated with the lower end of the reactor body, and an exhaust pipe is arranged at the upper end of the reactor body;

[0007] The reactor body is sequentially provided with a granular sludge bed and a clarified liquid from bottom to top;

[0008] The iron negative electrode and the metal mesh positive electrode are oppositely arranged in the clarified liquid, and a power supply is connected in series between the iron negative electrode and the metal mesh positive electrode;

[0009] The side wall of the reactor body corresponding to the clarified liquid is communicated with a water outlet pipe.

[0010] Further, the inside of the metal mesh positive electrode is sleeved with a hollow fiber membrane, and the water outlet pipe passes through the side wall of the reactor body and is correspondingly communicated with the hollow fiber membrane.

[0011] Further, the iron negative electrode and the metal mesh positive electrode are further connected in series with an adjusting resistor.

[0012] Further, the lower part of the clarified liquid corresponding to the positive and negative electrodes is provided with an aerator, the aerator is communicated with the exhaust pipe, and a fan is connected in series between the aerator and the exhaust pipe.

[0013] Further, the granular sludge bed is composed of granular activated carbon.

[0014] Further, the clarified liquid and the lower end of the reactor body are further connected with a reflux pipe.

[0015] The present application has the following beneficial effects:

[0016] (1) Here, in order to avoid the dispersion of granular sludge, the iron negative electrode and the metal mesh positive electrode are added and connected with an external power supply for ionization, so that the iron is ionized into Fe 2+ , Fe 2+It has strong flocculation effect, reduces the content of suspended sludge in the clarified liquid; the released divalent iron can connect various anions such as hydroxyl, acid radical, sulfate radical and phosphate radical ion to form large flocculation sludge, reduces the soluble protein and polysaccharide and converts into solidified extracellular high polymer, reduces the pore size blockage and the formation of high-strength attached sludge cake layer, thus the irreversible membrane pollution is reduced.

[0017] (2) The electric field effect can change the sludge properties of the mixed liquid / supernatant near the membrane; the extracellular high polymer protein content of the mixed liquid near the membrane is reduced, the divalent iron can reduce the electrostatic repulsion between microorganisms, and the zero-valent iron and the divalent iron can help to maintain a good low redox potential, promote the enrichment of methanogens and accumulate into groups.

[0018] (3) The membrane is used as a cathode, and under the action of the electric field, the membrane can form a repulsion with the membrane pollutants with anionic functional groups, reducing their attachment to the membrane surface. The electric field can accelerate the ion migration speed, accelerate the iron release, neutralize the acid, and provide a favorable living environment for the methanogens.

[0019] Of course, it is not necessary for any product implementing the present application to achieve all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0021] Figure 1 The structural schematic diagram of the present application.

[0022] In the drawings, the component list represented by each number is as follows:

[0023] Reactor body 1, sewage pipe 11, exhaust pipe 5, granular sludge bed 2, clarified liquid 3, iron negative electrode 31, metal mesh positive electrode 32, power supply 33, water outlet pipe 36, hollow fiber membrane 35, adjusting resistor 34, aerator 4, fan 51, granular activated carbon 21, reflux pipe 6. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0025] In the description of the present application, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "periphery" and the like indicate the orientation or positional relationship, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the components or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application.

[0026] As shown in Figure 1 : an iron electrode coupled anaerobic granular sludge membrane bioreactor, comprising a reactor body 1, cylindrical and vertically placed, the lower end of the reactor body 1 is communicated with a sewage pipe 11, the upper end of the reactor body 1 is provided with an exhaust pipe 5; for discharging the methane gas produced by the reaction, the treatment device is an anaerobic fermentation treatment device, and the reaction produces methane and other gases.

[0027] The reactor body 1 is sequentially provided with a granular sludge bed 2 and a clarified liquid 3 from bottom to top;

[0028] The iron negative electrode 31 and the metal mesh positive electrode 32 are oppositely arranged in the clarified liquid 3, and the iron negative electrode 31 and the metal mesh positive electrode 32 are connected in series with the power supply 33; pure iron represents 0-valent iron, and the metal mesh is a titanium mesh. The voltage is controlled at 1.2V.

[0029] The side wall of the reactor body 1 corresponding to the clarified liquid 3 is communicated with a water outlet pipe 36.

[0030] The present application is an anaerobic microbial fermentation processor, after the sewage enters the lower end of the reactor body and is fermented through the granular sludge bed, methane and other gases are produced and float up after fermentation, and the clarified liquid after degradation is in the upper layer. Due to the gas floating process and the water flow impact of the water inlet, the particles in the granular sludge bed will be dispersed, resulting in low degree of agglomeration of sludge particles, high mortality and loss rate of bacteria, and the fermentation efficiency of microorganisms will be greatly reduced after a period of time.

[0031] Here, in order to avoid the dispersion of granular sludge, iron negative electrode and metal mesh positive electrode are added and connected with power supply for ionization, so that iron is ionized into Fe 2+ , Fe 2+ has strong flocculation effect, reduces the content of suspended sludge in the clarified liquid; the released divalent iron can connect various anions such as hydroxyl, acid radical, sulfate radical and phosphate radical ions to form large flocculation sludge, reduce soluble protein and polysaccharide and convert them into solidified extracellular polymer, reduce pore size blockage and reduce the formation of high-strength attached cake layer, so that irreversible membrane pollution is reduced.

[0032] In addition, the electric field can change the sludge properties of the mixed liquor / supernatant near the membrane. The extracellular polymeric substances content of the mixed liquor near the membrane will decrease. The divalent iron can reduce the electrostatic repulsion between microorganisms. The zero-valent iron and the divalent iron can help maintain a good low redox potential, promote the enrichment of methanogens and accumulate into clusters.

[0033] The membrane is used as a cathode. Under the action of the electric field, the membrane can form a repulsion with the membrane pollutants with anionic functional groups, reducing the adhesion of the membrane pollutants on the membrane surface. The electric field can accelerate the ion migration speed, accelerate the iron release, neutralize the acid and provide a favorable living environment for the methanogens.

[0034] As shown in Figure 1 : the metal mesh anode 32 is sleeved with a hollow fiber membrane 35 inside, and the water outlet pipe 36 passes through the side wall of the reactor body 1 and corresponds to the hollow fiber membrane 35. The water outlet pipe is connected with a water pump to improve the water pressure. In addition, the hollow fiber membrane is added to the metal mesh anode for filtering the effluent. The target objects for filtration include nutrients, microorganisms and sludge residues. The filtration of nutrients is beneficial to increasing the nutrient content in the clarified liquid and promoting the growth of microorganisms. After the flocculation of Fe 2+ , the content of sludge residues is greatly reduced, and the membrane pollution is reduced.

[0035] As shown in Figure 1 : the iron anode 31 and the metal mesh anode 32 are further connected with a regulating resistor 34. The regulating resistor is used to adjust the voltage between the anode and the cathode.

[0036] As shown in Figure 1 : the clarified liquid 3 is provided with an aerator 4 below the positive and negative electrodes. The aerator 4 is connected with an exhaust pipe 5, and the aerator 4 and the exhaust pipe 5 are connected with a fan 51. The exhaust gas is partially reused. After the pressurization by the fan, the gas is returned to the clarified liquid for aeration, improving the microbial fermentation. The part of the gas does not contain oxygen and does not affect the activity of anaerobic bacteria.

[0037] The release of divalent iron changes the properties of the mixed liquor near the membrane, so that the particle size of the mixed liquor increases from colloidal to particulate, which does not easily cause the blockage of the membrane pore size. Instead, a loose mud cake layer is formed on the membrane surface, which can be blown off by trace aeration.

[0038] As shown in Figure 1 : the granular sludge bed 2 is composed of granular activated carbon 21. The granular activated carbon 21 is adsorbed and grown with anaerobic microorganisms.

[0039] As shown in Figure 1As shown: the clarified liquid 3 and the lower end of the reactor body 1 is also connected with reflux tube 6. The connection of the reflux tube upper end is located above the positive and negative motor, for the clarified liquid reflux again, secondary fermentation and filtration, so that the nutrient content in the water body is further reduced, in addition, the nutrient content in the clarified liquid is high, after reflux, it is beneficial to the activity of anaerobic bacteria.

[0040] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0041] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of the present specification. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. An iron electrode coupled anaerobic granular sludge membrane bioreactor, characterized in that: a reactor body (1) is provided, a sewage pipe (11) is communicated to the lower end of the reactor body (1), and an exhaust pipe (5) is arranged at the upper end of the reactor body (1); a granular sludge bed (2) and a clarified liquid (3) are sequentially arranged in the reactor body (1) from bottom to top; an iron negative electrode (31) and a metal mesh positive electrode (32) are oppositely arranged in the clarified liquid (3), and a power supply (33) is connected in series between the iron negative electrode (31) and the metal mesh positive electrode (32); a water outlet pipe (36) is communicated to the side wall of the reactor body (1) corresponding to the clarified liquid (3); a hollow fiber membrane (35) is sleeved in the metal mesh positive electrode (32), the water outlet pipe (36) passes through the side wall of the reactor body (1) and is correspondingly communicated to the hollow fiber membrane (35), and a water pump is connected in series to the water outlet pipe (36); an aerator (4) is arranged below the positive and negative electrodes corresponding to the clarified liquid (3), the aerator (4) is communicated to the exhaust pipe (5), and a fan (51) is connected in series between the aerator (4) and the exhaust pipe (5); the granular sludge bed (2) is composed of granular activated carbon (21).

2. The ferric electrode coupled anaerobic granular sludge membrane bioreactor according to claim 1, characterized in that: An adjusting resistor (34) is further connected in series between the iron negative electrode (31) and the metal mesh positive electrode (32).

3. The ferric electrode coupled anaerobic granular sludge membrane bioreactor according to claim 1, characterized in that: A reflux pipe (6) is further connected between the clarified liquid (3) and the lower end of the reactor body (1).

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