Fluidized collision type bioelectric reaction device suitable for high-carbon sewage treatment

Abstract

The application discloses a fluidized collision type bioelectric reaction device suitable for high-carbon sewage treatment, which comprises a reactor body, a capacitive electrically active biofilm carrier, an anode plate and a cathode plate. The reactor body is a cylinder, a plug flow reactor is installed at the bottom, and each area is separated by a grid; the capacitive electrically active biofilm carrier is a spherical body stacked by circular sheets, is made of polyethylene coated with an ITO film, and has stainless steel spikes on the surface; the cathode plate is made of graphite and has a cylindrical shape; the anode plate is made of sodium dodecyl sulfate and graphene-multiple-walled carbon nanotube composite stainless steel, has a cylindrical shape, and has a hollow plate wall; and a circuit is used to connect the anode and the cathode. The application uses the flow and collision of the capacitive electrically active biofilm carrier to complete electron transfer, enhances the mass transfer efficiency and activity of the electrically active biofilm, improves the treatment capacity for high-carbon wastewater, and has the advantages of high impact load resistance and low requirement for site area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a fluidized collision type bio-electric reaction device suitable for high-carbon sewage treatment. BACKGROUND

[0002] High-carbon sewage is a difficult problem in sewage treatment, and in the treatment process, the treatment efficiency is not high enough, so that the effluent quality cannot meet the standard. Due to the unique electron transfer mechanism, the electroactive biofilm is more efficient than other treatment methods in treating organic matter, and is a potential new type of sewage treatment method.

[0003] However, the electroactive biofilm is mainly suitable for sewage treatment with COD concentration lower than 500 mg / L, and has the following problems in treating high-carbon sewage, which seriously affects its application and promotion.

[0004] (1) The decrease of mass transfer efficiency. Due to the smooth surface of the electroactive biofilm, the contact efficiency of microorganisms and organic matter is low, and the mass transfer efficiency is poor; and the high-carbon sewage amplifies this defect, and for high-carbon wastewater with COD concentration of 1000 mg / L, the electroactive biofilm needs two to three cycles of circulation to meet the national first B standard.

[0005] (2) The decrease of microbial activity. When the electroactive microorganisms are in a constant current state for a long time, the activity will be greatly reduced; the fluorescence staining characteristic analysis of the electroactive biofilm running under high-carbon sewage shows that the total amount of organisms and the proportion of living cells significantly decrease with time.

[0006] (3) The influence of fluctuation of influent COD concentration. When the influent COD load changes by more than 20% in a short period of time and maintains the changed load, the electroactive biofilm cannot immediately adapt to the environmental change, and needs a recovery period of about 10 days to make the treatment efficiency reach the initial level, resulting in the extension of the treatment period and the deterioration of the effluent quality.

[0007] Therefore, aiming at the problems of the prior art, the application provides a fluidized collision type bioelectric reaction device suitable for high-carbon sewage treatment.The application uses a capacitive electrically active biofilm carrier as a growth place of electrically active microorganisms, and makes the electrically active biofilm operate in a fluidized state in the reactor.The main advantages of the application include (1) improving mass transfer efficiency;by the fluidized state, the collision efficiency of the treatment core, the capacitive electrically active biofilm carrier, and organic matters is improved, so that the mass transfer efficiency and the treatment efficiency are improved; (2) optimizing power supply mode and improving microbial activity; the capacitive electrically active biofilm carrier is used to make the electric charge in the treatment process gather first, and then release the electric charge in the form of collision to form a periodic current circulation; and (3) enhancing the ability to resist COD load fluctuation; by increasing the total amount and activity of microorganisms, and combining the mixing effect of sewage circulation in the reactor, the direct impact of the load is diluted, and the ability of the reactor to resist load fluctuation is improved. SUMMARY

[0008] Aiming at the problems of the prior art, the application provides a fluidized collision type bioelectric reaction device suitable for high-carbon sewage treatment.The application uses a capacitive electrically active biofilm carrier as a growth place of electrically active microorganisms, and makes the electrically active biofilm operate in a fluidized state in the reactor.The main advantages of the application include (1) improving mass transfer efficiency;by the fluidized state, the collision efficiency of the treatment core, the capacitive electrically active biofilm carrier, and organic matters is improved, so that the mass transfer efficiency and the treatment efficiency are improved; (2) optimizing power supply mode and improving microbial activity; the capacitive electrically active biofilm carrier is used to make the electric charge in the treatment process gather first, and then release the electric charge in the form of collision to form a periodic current circulation; and (3) enhancing the ability to resist COD load fluctuation; by increasing the total amount and activity of microorganisms, and combining the mixing effect of sewage circulation in the reactor, the direct impact of the load is diluted, and the ability of the reactor to resist load fluctuation is improved.

[0009] To solve the above technical problems, the technical scheme adopted by the application is:

[0010] A fluidized collision type bioelectric reaction device suitable for high-carbon sewage treatment, comprising a reactor body, a capacitive electrically active biofilm carrier, an anode plate and a cathode plate.

[0011] The reactor body is a cylinder; a plug flow device is installed at the bottom of the reactor; from bottom to top, there are the plug flow device area, the water inlet area, the reaction center part and the water outlet area, which are separated by a grid.

[0012] The material of the capacitive electrically active biofilm carrier is polyethylene, and the surface is plated with an ITO film; the overall shape of the capacitive electrically active biofilm carrier is a sphere, which is stacked by circular sheets, and the sheets are full of holes; the surface has spikes, and the material of the spikes is stainless steel, and the height of the spikes is one fifth of the radius of the sphere.

[0013] The material of the cathode plate is graphite, and the shape is a cylinder; the cathode plate is located in the middle of the reactor and is attached to the inner wall of the reactor.

[0014] The anode plate material is sodium dodecyl sulfate and graphene-multiple wall carbon nanotube composite stainless steel, which is in the shape of a cylinder; the radius is smaller than that of the cathode plate and is located inside the cathode plate; the plate wall of the anode plate is in a hollow shape, and water flow can pass through the pores, and the capacitive electroactive biofilm carrier cannot pass through the pores; a wiring is used to connect the anode and the cathode.

[0015] The present application has the following advantages:

[0016] 1. Higher mass transfer efficiency for high-carbon wastewater. Compared with traditional electroactive biofilms, the present application uses a fluidized method to treat organic matter, which increases the collision efficiency of the electroactive biofilm on the capacitive electroactive biofilm carrier and the organic matter in the wastewater, thereby improving the mass transfer efficiency and treatment efficiency.

[0017] 2. Microorganisms can maintain activity for a long time. The capacitive electroactive biofilm carrier is used to make the charges in the treatment process first gather and then release in the form of collision to form a periodic current cycle, thereby optimizing the power supply mode. This fluctuating power supply mode can promote the metabolism of electroactive microorganisms, stimulate their electron transfer system and improve the structure of the biofilm, ultimately enabling the microorganisms to maintain activity for a long time.

[0018] 3. Strong resistance to COD load fluctuations. Due to the large specific surface area of the carrier and the unique power supply mode, the total amount of microorganisms in the reactor is larger and more active, and has good adaptability to load changes. In addition, the wastewater circulation in the reactor has good mixing effect, and the pollutants entering the reactor will be diluted, and the load will be shared by each carrier, reducing the direct impact of the load; by changing the rate of wastewater circulation, dilution can be effectively accelerated, and the resistance to load fluctuations can be improved. When the load fluctuation of the influent is within 20%, it basically does not affect the system.

[0019] 4. Reduce the floor area. Due to the higher volumetric load, the space required by the present application is smaller than that of traditional sludge treatment methods. It is suitable for places with limited space or upgrading and reconstruction of wastewater treatment plants. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The side sectional view of the reactor and the three-dimensional view of the reaction core in the present application are shown.

[0021] Figure 2 The three-dimensional view (a) of the capacitive electroactive biofilm carrier and the three-dimensional view (b) of its slice in the present application are shown.

[0022] Figure 3 The reaction flow chart of the capacitive electroactive biofilm carrier in the present application is shown.

[0023] Figure 4 The current density measurement data graph in Example 1 is shown.

[0024] Figure 5 COD content change in Example 1 is shown.

[0025] Figure 6 Treatment effect comparison under load fluctuation in Example 3 is shown.

[0026] Among them:

[0027] 1, grid; 2, cathode; 3, anode; 4, pusher. DETAILED DESCRIPTION

[0028] The invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0029] The reactor mechanism in the invention is as follows:

[0030] Step 1, culture of electrically active biofilm: put the capacitive electrically active biofilm carrier into the reactor, add a solution containing electrically active microbial strains, add vitamins, sodium acetate, and sulfate buffer under an electric environment, so that the capacitive electrically active biofilm carrier hangs a biofilm; select a certain volume of carrier to remain in the reactor, so that the filling rate of the reactor meets the standard requirements.

[0031] In step 1, the main material of the capacitive electrically active biofilm carrier is light material, and its density range is 0.89-0.91 g / cm 3 , and can move freely with the water flow. The culture period of the biofilm on the carrier is 15 days, and when the biofilm thickness is 0.1 to 1 mm, it is considered to be successfully cultured.

[0032] The filling rate generally ranges from 30% to 50%. The volume of the carrier and the filling rate of the reactor can be calculated according to the following formula:

[0033]

[0034] In the formula, Q represents the design flow (m 3 / d); S o represents the influent BOD5 concentration (mg / L); S e represents the effluent BOD5 concentration (mg / L); q represents the capacitive electrically active biofilm carrier surface load; ε represents the specific surface area of the capacitive electrically active biofilm carrier; V represents the volume of the capacitive electrically active biofilm carrier required (m 3 ); n1 represents the filling rate; V N represents the reactor volume (m 3 ).

[0035] Step 2, fluidized motion: sewage enters the reactor from the water inlet, and the pusher is started to make the sewage circulate in the reactor. The suspended capacitive electroactive biofilm carrier is pushed by the water flow and continuously contacts and collides with organic matter in the process, and the electroactive microorganisms on the capacitive electroactive biofilm carrier decompose the organic matter.

[0036] In step 2, the stirrer makes the flow rate of water greater than 0.3 m / s to ensure that the capacitive electroactive biofilm carrier is in a flowing state in the reactor. The electroactive biofilm on the capacitive electroactive biofilm carrier decomposes the organic matter into H + and CO2, and the electrons generated in the reaction process are gathered on the spikes of the carrier.

[0037] In addition to the electroactive biofilm on the capacitive electroactive biofilm carrier, an electroactive biofilm will also grow on the anode of the reactor. The overall reaction of the biofilm on the capacitive electroactive biofilm carrier and the biofilm on the anode is the same. The difference is that the electrons generated in the reaction are directly transmitted to the cathode by the wire. The anode material, sodium dodecyl sulfate and graphene-multiple wall carbon nanotube composite stainless steel, has good biocompatibility and hydrophilicity, which helps the attachment of electroactive microorganisms and the transmission of electrons.

[0038] The reaction of the electroactive biofilm on the carrier and the anode surface with organic matter is as follows.

[0039] Organic matter - e - → H + + CO2

[0040] Step 3, complete microbial reaction: the suspended capacitive electroactive biofilm carrier collides with the anode plate during the flow process, the electrons stored on the spikes of the carrier are transferred to the anode and transmitted to the cathode under the action of voltage, and water is generated at the cathode; the treated sewage is discharged from the water outlet.

[0041] In step 3, H + generated in the previous step, H + passes through the hollow of the anode to the cathode. The formula of this step is as follows.

[0042] H + + O2 + e - → H2O

[0043] Example 1: Upgrading and reconstruction of sewage plant

[0044] The BOD concentration of the sewage entering the sewage plant is about 600 mg / L. Part of the sewage is introduced into the reactor, and the volume of the reactor is about 20 m 3 The radius of the capacitive electroactive biofilm carrier is 20 mm.

[0045] (1) Culturing the electrically active organic matter on the capacitive electrically active biofilm carrier, the culture period is 15 days, and the filling rate is calculated by the following formula

[0046]

[0047] In the formula, Q represents a design flow rate, 1*10 3 m 3 / d; S o represents an influent BOD5 concentration, 600 mg / L; S e represents an effluent BOD5 concentration, estimated as 20 mg / L; q represents a capacitive electrically active biofilm carrier surface load, 0.235 g / (m 2 / d); ε represents a specific surface area of the capacitive electrically active biofilm carrier, 350 m 2 / m 3 ; V represents a volume of capacitive electrically active biofilm carrier required (m 3 ); n1 represents the filling rate; V N represents a reaction tank volume, 20 m 3 .

[0048] It is calculated that 7.05 m 3 of capacitive electrically active biofilm carrier is required, and the filling rate is 35.3%.

[0049] (2) Start the pusher to make the sewage circulate in the reactor, and turn on the electric circuit. After 3 h of reaction in the reactor, the current density of the electrode plate is measured, and the result is shown in Figure 4 , which proves that the electrically active microorganism in the reactor is in a fluctuating current state, and has good working efficiency in this state.

[0050] (3) The effluent after treatment is shown in Table 1, which meets the first level B standard. In addition, the COD content of the sewage is measured by the sampling titration method every hour after the device starts to work, and the result is shown in Figure 5 .

[0051] Table 1 Sewage treatment data table

[0052]

[0053] Example 2: Long-term sewage treatment

[0054] In long-term sewage treatment, the activity of microorganisms in the traditional electrically active biofilm device will decrease greatly. The present application is suitable for long-term sewage treatment, can maintain the ecological balance of microorganisms, and stabilize the activity of microorganisms.

[0055] A group of conventional electroactive biofilm systems are used as a control group. The same vitamins, sodium acetate, sulfate buffer and solution containing electroactive microbial strains are added to the conventional electroactive biofilm system and the present application, and after 10 days of culture, the microorganisms are subjected to metagenomic sequencing. The influent wastewater COD concentration is controlled at 1500 mg / L, and after 60 days of treatment, metagenomic sequencing is performed again. The microbial sequencing results are shown in Table 2. From Table 2, it can be observed that the difference in microbial population is not large at the beginning of the culture, but after long-term wastewater treatment, the total number of microbial species, diversity and evenness in the conventional electroactive biofilm have decreased significantly, while the present application has better maintained the microbial ecology at the beginning of operation.

[0056] Table 2 Microbial metagenomic sequencing data

[0057]

[0058]

[0059] Example 3: Emergency treatment

[0060] In the process of solving example 1, the emergency situation of great fluctuation of influent water quality will be encountered, and the wastewater treatment system is easily affected by the change of organic load. When the organic load increases rapidly, the biofilm may not be able to adapt to this change immediately, resulting in a decrease in removal efficiency; on the contrary, if the load decreases, the microorganisms in the biofilm may be nutritionally deficient, thereby affecting their activity and growth, which will also have a negative impact on the effluent water quality. The present application can effectively cope with the load impact and the treatment effect is stable.

[0061] The influent organic load is controlled, and the initial influent COD concentration is 1500 mg / L. After 5 days, the influent is changed to wastewater with a COD concentration of 2000 mg / L. After another 10 days, the influent is changed back to wastewater with a COD concentration of 1500 mg / L. A group of conventional electroactive biofilm systems are used as a control group, and the change in COD concentration is monitored by sampling titration, and the results are shown in Figure 6 .

[0062] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above embodiments, and various equivalent transformations of the technical solutions of the present application can be made within the technical concept of the present application, and these equivalent transformations all belong to the protection scope of the present application.

Claims

1. A fluidized bed collision bioelectrochemical reactor suitable for treating high-carbon wastewater, characterized in that: It includes the reactor body, capacitively electroactive biofilm carrier, anode plate, and cathode plate; The capacitive electroactive biofilm carrier is made of polyethylene and coated with an LTO film. The overall shape of the capacitive electroactive biofilm carrier is spherical, which is composed of stacked circular sheets with pores. The surface has spikes made of stainless steel, and the height of the spikes is one-fifth of the radius of the sphere. The anode plate is made of stainless steel composite of sodium dodecyl sulfate and graphene-multi-walled carbon nanotubes, and is cylindrical in shape. Its radius is smaller than that of the cathode plate, and it is located inside the cathode plate. The wall of the anode plate is hollow, and water flows through the pores, while the capacitive electroactive biofilm carrier cannot pass through the pores. The anode and cathode are connected by a circuit.

2. The fluidized bed collision bioelectrochemical reactor for high-carbon wastewater treatment according to claim 1, characterized in that: The reactor body is cylindrical; a flow booster is installed at the bottom of the reactor; from bottom to top, the flow booster area, the inlet area, the reaction center, and the outlet area are separated by a grid.

3. The fluidized bed collision bioelectrochemical reactor for high-carbon wastewater treatment according to claim 1, characterized in that: The cathode plate is made of graphite and is cylindrical in shape; it is located in the middle of the reactor and attached to the inner wall of the reactor.

4. The method of using the fluidized bed collision bioelectrochemical reactor for high-carbon wastewater treatment according to any one of claims 1 to 3, characterized in that, The specific steps include the following: Step 1: Cultivating Electroactive Microorganisms: Place the capacitively electroactive biofilm carrier into the reactor, add a solution containing electroactive microbial strains, and add vitamins, sodium acetate, and sulfate buffer solution under an electric current to allow a biofilm to form on the capacitively electroactive biofilm carrier. Select a certain volume of carrier to remain in the reactor, ensuring that the reactor's filling rate meets the standard requirements. The carrier volume and reactor filling rate are calculated using the following formula: In the formula, Q represents the design flow rate (m³ / s). 3 / d); S o Indicates the influent BOD5 concentration (mg / L); S e q represents the effluent BOD5 concentration (mg / L); q represents the surface loading of the capacitively electroactive biofilm carrier; ε represents the specific surface area of ​​the capacitively electroactive biofilm carrier; V represents the required volume of the capacitively electroactive biofilm carrier (m³). 3 ); n1 represents the fill rate; V N Represents the volume of the reaction tank (m³) 3 ); Step 2: Fluidized flow: Wastewater enters the reactor through the inlet, and the flow promoter is activated to circulate the wastewater in the reactor. The suspended capacitive electroactive biofilm carrier flows under the impetus of the water flow. Step 3: Complete the microbial reaction: Start the circuit, and the capacitive electroactive biofilm carrier collides with the anode plate during the flow process to complete the reaction process; the treated wastewater is discharged from the outlet.

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