CN202322491U - Three-dimensional electrode biological film reactor - Google Patents

Abstract

The utility model discloses a three-dimensional electrode biofilm reactor. A diaphragm concentric with the reactor body is arranged in the reactor body, and the diaphragm separates the reactor into a circular anode area and an annular cathode area; the anode area is filled with There are microbial carrier fillers, and a positive electrode is set in the center; a negative electrode is set in the cathode area, and conductive particles are filled in the cathode area as the third electrode, and the negative electrode and conductive particles are also used as microbial carriers; the bottom of the anode area is equipped with a water inlet pipe , the cathode area is provided with a water outlet pipe, and the water outlet pipe is arranged on the outer wall of the upper end of the reactor body. In the same electrode biofilm reactor, the utility model uses electrochemical action to create a suitable environment for microorganisms, and provides electron acceptors and electron donors for nitrification and denitrification respectively, so as to achieve the purpose of effectively treating ammonia nitrogen wastewater and low energy consumption , high efficiency, simple structure and easy operation.

Description

A three-dimensional electrode biofilm reactor

technical field

The utility model relates to a wastewater treatment system, specifically a three-dimensional electrode biofilm reactor suitable for treating wastewater with a low carbon-to-nitrogen ratio and high ammonia-nitrogen ratio, and belongs to the technical field of water treatment. The utility model combines the biofilm method and the electrochemical method in the same reactor to complete the whole process of nitrification and denitrification treatment of waste water with low carbon-to-nitrogen ratio and high ammonia-nitrogen ratio. the

Background technique

With the development of industrial and agricultural production and the improvement of urbanization in my country, the discharge of urban sewage has increased rapidly. A large number of untreated or treated urban sewage whose effluent nitrogen and phosphorus are still difficult to meet the standards are discharged into urban lakes and rivers, causing nitrogen and phosphorus pollution in water bodies. It is becoming more and more serious, and its direct consequence is eutrophication of water body. the

Nitrogen in water mainly exists in the form of organic nitrogen and inorganic nitrogen. Organic nitrogen includes protein, polypeptide, amino acid and urea, etc. Organic nitrogen is converted into inorganic nitrogen through microbial decomposition, mainly ammonia nitrogen, nitrite nitrogen and nitrate nitrogen. The removal of nitrogen in wastewater is mainly through nitrification and denitrification processes, so that various forms of nitrogen are converted into gaseous nitrogen (N ₂ , N ₂ O, etc.) and escape from the water body to purify the water body. For the treatment of wastewater with low carbon-to-nitrogen ratio and high ammonia-nitrogen, there are problems such as insufficient alkalinity and carbon source in the traditional biological nitrification and denitrification process, so it is necessary to develop new nitrogen removal methods.

The traditional biological denitrification process is to use organic matter in wastewater, or add organic matter such as methanol and ethanol as electron donors for denitrification, and convert nitrate nitrogen into non-toxic nitrogen. By adding organic matter, a higher denitrification rate can be obtained, but there will be residual organic matter in the effluent, which not only affects the quality of the effluent water but also increases the operating cost. For wastewater with high ammonia nitrogen content, such as sludge precipitated liquid and landfill leachate from sewage treatment plants, when traditional biological denitrification methods are used for treatment, organic carbon sources need to be added to meet the needs of heterotrophic denitrification, which consumes a lot of energy. Processing costs are high. the

In recent years, on the basis of the traditional nitrification-denitrification process, a series of high-efficiency and energy-saving denitrification technologies have been developed, such as SHARON, ANAMMOX, and CANON combined with the two. These processes utilize nitrous acid-type denitrification and anammox to shorten the nitrogen conversion process and achieve energy and electron donor savings. In contrast, the electrode biofilm method is another potential denitrification method. This technology uses hydrogen autotrophic bacteria to carry out denitrification, and can remove NO _x ^- under the condition of little or no organic carbon source. Because the product is clean, it will not increase the burden on the effluent; more importantly, it overcomes the weaknesses of residual gas loss and difficult operation caused by direct external hydrogen supply, and controls the complex biochemical reaction process with simple current regulation. Energy consumption Low and easy to operate.

At present, the electrode biofilm method is mostly aimed at the removal of nitrate in water, and it is still rare to apply this method to the treatment of wastewater with low carbon-to-nitrogen ratio and high ammonia-nitrogen. the

Utility model content

Aiming at the above-mentioned shortcomings in the prior art, the utility model provides a three-dimensional electrode biofilm reactor with low energy consumption, high efficiency and simple structure for treating waste water with low carbon-to-nitrogen ratio and high ammonia-nitrogen ratio. the

In order to achieve the above purpose, the technical solution adopted by the utility model is as follows: a three-dimensional electrode biofilm reactor, which includes a reactor body, the reactor body is a cylindrical structure with a bottom, and a There is a diaphragm concentric with the reactor body, which divides the inner area of the reactor into two parts. The circular area inside the diaphragm is the anode area, and the annular area between the outside of the diaphragm and the inner wall of the reactor body is the cathode area; the anode area is filled with There are microbial carrier fillers, and a positive electrode is set in the center; a negative electrode is set in the cathode area, and the negative electrode is close to the inner wall of the reactor body, and the cathode area is filled with conductive particles as the third electrode, and the negative electrode and conductive particles serve as the third electrode. Microbial carrier; the bottom of the anode area is provided with a water inlet pipe, the cathode area is provided with a water outlet pipe, and the water outlet pipe is arranged on the outer wall of the upper end of the reactor body. the

Further, a return pipe is provided in the middle of the outer wall of the reactor body, the return pipe communicates with the water inlet pipe, and the return pipe is used to return the water in the cathode area to the anode area. the

The positive electrode is an inert metal material; the negative electrode is graphite, carbon rod, activated carbon fiber felt or stainless steel mesh; the conductive particles are activated carbon particles or anthracite. the

The diaphragm is a hydrophilic film such as cellulose acetate, aromatic polyamide or polyvinylidene fluoride. the

The microbial carrier filler filled in the anode area is an insulating material such as elastic filler, soft filler or suspended filler. the

Compared with the prior art, the utility model has the following advantages:

1) Electrolysis provides a suitable environment for the growth and reproduction of microorganisms, that is, the anode area is aerobic, while the cathode area is anoxic. At the same time, microorganisms use electrolysis products as metabolic substrates. There is a good synergy between electrode electrolysis and microbial denitrification.

2) When the positive electrode (anode) is an inert metal material, the electrode reaction is mainly based on oxygen evolution, which saves the energy required for aeration and reduces energy consumption. the

3) The negative electrode (cathode) electrolyzes water to produce hydrogen in situ, and the hydrogen diffuses from the biofilm to the outside. Compared with the external supply of hydrogen, the mass transfer direction and mass transfer power are both enhanced. the

4) Microbial denitrification and denitrification in the cathode area uses the hydrogen produced by the electrolysis as the electron donor, without the need for an external organic carbon source, and the product is clean. the

5) The cathode area is filled with granular conductive particles. On the one hand, the particles are filled as a microbial attachment carrier, which increases the microbial load in the reactor; on the other hand, the specific surface area is increased, the mass transfer effect is improved, and the current efficiency and treatment efficiency are improved. the

6) This reactor regulates the complex biological system by applying simple electric current, and the operation is simple. the

The utility model can realize the use of electrochemical action to create a suitable environment for microorganisms in the same electrode biofilm reactor, and provide electron acceptors and electron donors to perform nitrification and denitrification respectively, thereby achieving the purpose of effectively treating ammonia nitrogen wastewater. the

Description of drawings

Fig. 1 is the structural representation of the utility model.

Among them, 1-reactor body; 2-positive electrode; 3-negative electrode; 4-conductive particles; 5-diaphragm; 6-water inlet pipe; 7-water outlet pipe; 8-reflux pipe; DC regulated power supply. the

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail. the

The three-dimensional electrode biofilm reactor of the utility model is mainly used for treating waste water with low carbon-to-nitrogen ratio and high ammonia-nitrogen ratio. 1 is provided with a diaphragm 5 concentric with the reactor body, which divides the inner area of the reactor into two parts, the anode area and the cathode area. The annular area is the cathode area. The anode area is filled with microbial carrier filler 9, and a positive electrode 2 is provided in the center; a negative electrode 3 is provided in the cathode area, and the negative electrode is close to the inner wall of the reactor body, and conductive particles 4 are filled in the cathode area as the third electrode , the negative electrode 3 and the conductive particles 4 simultaneously serve as microbial carriers. Microorganisms attach to the surface of the carrier in the anode and cathode regions to form a biofilm. The positive electrode 2 (anode) and the negative electrode 3 (cathode) are respectively connected to the positive pole and the negative pole of the DC stabilized voltage power supply 10 through wires. The positive electrode 2, the negative electrode 3 and the conductive particles 4 together constitute a three-dimensional electrode. A water inlet pipe 6 is provided at the bottom of the anode area, and a water outlet pipe 7 is provided at the cathode area through which the treated water is discharged out of the system. The water outlet pipe 7 is arranged on the outer wall of the upper end of the reactor body. the

The water flow of the reactor of the utility model adopts an upflow type, water enters from the bottom and exits from the top. A return pipe 8 is provided in the middle of the outer wall of the reactor body, and the return pipe 8 communicates with the water inlet pipe 6 for returning the water in the cathode area to the anode area. Since H ⁺ is produced by electrolysis at the anode and alkali is produced during the denitrification process in the cathode area, the water in the cathode area returns to the anode area to adjust the pH value.

The positive electrode material is selected from an inert material that has good electrical conductivity, an electrode potential higher than the oxygen potential of hydroelectrolysis, and is not easily oxidized, such as inert metal materials such as nickel, copper, and titanium. The negative electrode material is selected from carbonaceous or other materials with stable performance and rough surface, such as graphite, carbon rod, activated carbon fiber felt or stainless steel mesh. The third electrode, that is, the conductive particles filled in the cathode area selects materials with low resistance, high mechanical strength, and stable physical and chemical properties, such as activated carbon particles, anthracite, and the like. the

The separation membrane material of the anode area and the cathode area is a hydrophilic membrane material that can block gas transmission and has a certain water permeability and ion passage capacity, such as cellulose acetate, aromatic polyamide or polyvinylidene fluoride. the

The microbial carrier filler filled in the anode area is an insulating material such as elastic filler, soft filler or suspended filler. the

The pole spacing is 1~8cm. If the pole spacing is too large, the current efficiency of the reactor will be reduced and the energy consumption will be increased. the

The electrode biofilm method is a process of coupling electrochemical action and biological action. The reaction principle is as follows:

In the electrode biofilm reactor, the anode electrolyzes water to produce O ₂ , forms an aerobic environment in the anode area, and provides electron acceptors for biological nitrification for the growth of nitrifying bacteria in the anode area, with CO ₂ , CO ₃ ^2- , HCO ₃ ^- as a carbon source for nitrification:

55NH ₄ ⁺ +76O ₂ +109HCO ₃ ^- →C ₅ H ₇ O ₂ N+54NO ₂ -+57H ₂ O+104H ₂ CO ₃

400NO ₂ ^- +NH ₄ ⁺ +4H ₂ CO ₃ +195O ₂ +HCO ₃ ^- →C ₅ H ₇ O ₂ N+400NO ₃ ^- +3H ₂ O

In the electrode biofilm reactor, the cathode electrolyzes water to generate _H2 , forming an anoxic/anaerobic environment in the cathode area, and providing electron donors for biological denitrification for denitrification fixed on the surface of the cathode and the surface of the third electrode Bacteria use for denitrification and denitrification:

NO ₃ ^- +3[H]→0.5N ₂ +0H ^- +H ₂ O

NO ₂ ^- +5[H]→0.5N ₂ +0H ^- +2H ₂ O

In this way, the microorganisms in the reactor can make full use of the electrolysis product to carry out nitrification and denitrification denitrification. The utility model can be used for denitrification treatment of waste water with low carbon-to-nitrogen ratio and high ammonia-nitrogen. Under the condition of a small amount or no organic carbon source, the removal of ammonia nitrogen can be realized, and the complicated biochemical reaction process can be carried out by simple current regulation. control, clean product, low energy consumption, simple structure, convenient operation and low manufacturing cost.

The utility model takes waste water with low carbon-nitrogen ratio and high ammonia-nitrogen as the processing object, adopts a three-dimensional electrode biofilm reactor, enters water in the anode area, and discharges water in the cathode area. In the same reactor, biological nitrification and denitrification are combined with electrochemical oxidation. Nitrification mainly occurs in the anode area, and denitrification mainly occurs in the cathode area. Under the following control conditions: the ammonia nitrogen volume load of the influent is less than 1.5kgN/(m ³ ·d), the C/N is 0~3, the temperature is controlled at 25~35℃, the pH value of the influent is 6.5~8.0, and the hydraulic retention time More than 12h, when the current density is less than 0.021mA/cm ² , the electrode biofilm denitrification process can be well realized, and the removal rate of total nitrogen in the effluent is above 70%.

A specific embodiment is given below to illustrate the utility model to help understanding. the

Taking artificially prepared simulated ammonia nitrogen wastewater (NH ₄ ⁺ -N concentration of 100mg/L) as the research object, a plexiglass cylinder with a volume of 12.7L was used as the reactor. The anode and cathode regions are separated by cellulose acetate membrane. The anode is a titanium rod with a length of 55 cm and a diameter of 1 cm, which is placed in the center of the anode area (that is, the reactor) with an effective area of 157.1 cm ² . The anode area is filled with ordinary filter cotton as a microbial carrier. The cathode is made of activated carbon fiber felt, which is closely attached to the inner wall of the reactor, with an effective area of 2513cm ² . The cathode area is filled with activated carbon particles and glass beads, the filling ratio is 8:2 (volume ratio), wherein the activated carbon is coal-based columnar particles, the column length is 2~7mm, the particle size is 2~3mm, the glass bead particle size is 2~3mm, and the filling height is 30cm . The electrode spacing is 8cm.

Artificially prepared water uses K ₂ HPO ₄ and KH ₂ PO ₄ as buffers, C/N is 0.5, sodium acetate is used as organic carbon source, the temperature is maintained at about 30°C, the pH of the influent is about 7.8, and trace elements are properly supplemented . The wastewater with low carbon-nitrogen ratio and high ammonia-nitrogen was treated under the conditions of output voltage of DC stabilized power supply of 10V, current density of 0.013mA/cm ² , and hydraulic retention time of 24h. The NH ₄ ⁺ -N removal rate of the treated water is over 90%, and the TN removal rate is over 70%.

Claims (5)

1. A three-dimensional electrode biofilm reactor, which comprises a reactor body (1), is characterized in that: the reactor body (1) is a cylindrical structure with a bottom, and the reactor body (1) is provided with A diaphragm (5) concentric with the reactor body, the diaphragm divides the inner area of the reactor into two parts, the circular area inside the diaphragm is the anode area, and the annular area between the outside of the diaphragm and the inner wall of the reactor body is the cathode area; The area is filled with microbial carrier filler (9), and a positive electrode (2) is provided in the center; a negative electrode (3) is provided in the cathode area, and the negative electrode is close to the inner wall of the reactor body, and the cathode area is filled with conductive particles ( 4) As the third electrode, the negative electrode (3) and the conductive particles (4) serve as microbial carriers at the same time; the water inlet pipe (6) is provided at the bottom of the anode area, and the water outlet pipe (7) is provided at the cathode area, and the water outlet pipe is located in the reactor The outer wall of the upper end of the body. 2. The three-dimensional electrode biofilm reactor according to claim 1, characterized in that: a return pipe (8) is provided in the middle of the outer wall of the reactor body (1), and the return pipe (8) communicates with the water inlet pipe (6). The return pipe is used to return the water part of the cathode area to the anode area. 3. The three-dimensional electrode biofilm reactor according to claim 1 or 2, characterized in that: the positive electrode (2) is an inert metal material; the negative electrode (3) is graphite, carbon rod, activated carbon fiber felt or stainless steel mesh; the conductive particles (4) are activated carbon particles or anthracite. 4. The three-dimensional electrode biofilm reactor according to claim 3, characterized in that: the diaphragm (5) is a hydrophilic film with the ability to block gas, and the hydrophilic film is cellulose acetate, aromatic polyamide or polyvinylidene fluoride. 5. The three-dimensional electrode biofilm reactor according to claim 4, characterized in that the microbial carrier filler (9) filled in the anode area is elastic filler, soft filler or suspension filler made of insulating material.

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