Rotary oscillation biological electric reaction device suitable for high-carbon sewage treatment

Abstract

This invention discloses a rotary oscillating bioelectric reactor suitable for treating high-carbon wastewater. The device includes a reactor body, a rotary oscillating carrier, a rotary oscillating graphite plate, and a rotary oscillating actuator. The reactor is cylindrical, and from bottom to top, it consists of an inlet zone, a rotary oscillating actuator, a rotary oscillating graphite plate, a rotary oscillating carrier, another rotary oscillating actuator, and an outlet zone. The rotary oscillating carrier is made of a highly conductive metal, preferably aluminum alloy, and has mesh openings. Both the rotary oscillating carrier and the rotary oscillating graphite plate are circular, with a diameter of nine-tenths of the reactor's inner diameter, and along the circumference, the carrier surface is alternately decorated with grooves and protrusions. The rotary oscillating carrier is connected to the anode of a power supply, and the rotary oscillating graphite plate is connected to the cathode. Both are connected to the rotary oscillating actuator via transmission rods. This invention uses rotary oscillation to agitate the water, creating a balanced organic matter concentration, enhancing the adaptability of microorganisms to environmental changes. Simultaneously, the periodically changing electric field enhances the activity and mass transfer efficiency of the electroactive biofilm, improving the treatment efficiency of high-carbon wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a rotating oscillating bioelectric reactor suitable for treating high-carbon wastewater. Background Technology

[0002] High-carbon wastewater typically refers to wastewater with a high organic carbon content, characterized by a high chemical oxygen demand (COD) and difficulty in biological treatment, such as industrial wastewater and domestic wastewater. Methods for treating high-carbon wastewater include carbon adsorption, activated sludge processes, and electroactive biofilm processes. Among these, the electroactive biofilm process, due to its unique electron conduction mechanism, has higher efficiency in treating high-carbon wastewater and is a promising new wastewater treatment method.

[0003] However, current electroactive biofilms suffer from the following problems in the treatment of high-carbon wastewater, which seriously affect their wastewater treatment efficiency:

[0004] (1) The carbon treatment performance varies greatly in different biofilm microregions. Due to the large differences in microbial activity in different biofilm microregions, the carbon treatment efficiency is high, the COD concentration is low, and the electrons are removed in the high-activity biofilm region, while the carbon treatment efficiency is low, the COD concentration is high, and the electrons are removed in the low-activity biofilm region. Therefore, a potential difference will be formed inside the carrier. Electrons in the high-activity biofilm region will not be transferred to the outside, but will be directly conducted to the low-activity region. The accumulation of electrons in the low-activity region will further hinder the microorganisms in that region from treating organic matter, thus creating a vicious cycle that causes an electronic imbalance in the entire carrier and ultimately leads to the collapse of overall performance.

[0005] (2) Microorganisms have low activity under constant electric field conditions. When electroactive microorganisms are in a constant electric field for a long time, they will exhibit inertia, resulting in a significant decrease in activity. RNA sequencing of electroactive biofilms operating in high carbon wastewater revealed that the expression levels of carbon removal-related genes decreased significantly over time.

[0006] (3) The contact area between microorganisms and organic matter is small. The surface of electroactive biofilm is smooth, and the contact area with organic matter per unit volume is small, resulting in low electron and organic matter transport efficiency. For high carbon wastewater with a COD concentration of 1500 mg / L, it takes 10 days to treat the high carbon wastewater to the national Class B standard.

[0007] Therefore, in response to the problems of existing technologies, this invention proposes a rotating oscillating bioelectric reactor suitable for high-carbon wastewater treatment. This invention uses an oscillating carrier as a growth site for electroactive microorganisms, and uses rotational oscillation to enable the electroactive biofilm to operate within the reactor. The main advantages of this invention include: (1) mitigating COD concentration differences in different micro-zones. Through rotational oscillation, the high-carbon wastewater is fully agitated, reducing the concentration differences of organic matter, ensuring that the number of electrons removed in each micro-zone is similar, the potential difference is small, and the carrier's electronic balance is maintained. (2) Enhancing microbial activity. Using a combination of a rotating oscillating carrier and a rotating oscillating graphite plate for rotational oscillation optimizes the power supply mode, forming a periodically changing electric field to maintain high microbial activity. (3) Increasing the contact area between microorganisms and organic matter. The rotating oscillating carrier has mesh openings, expanding the attachment area of ​​the electroactive biofilm, increasing the contact area between the electroactive biofilm and organic matter, and improving decarbonization efficiency. Summary of the Invention

[0008] The technical problem this invention aims to solve is to address the shortcomings of the existing technology by providing a rotating oscillating bioelectrochemical reactor suitable for treating high-carbon wastewater. This invention uses a rotating oscillating carrier as the growth site for electroactive microorganisms, placing the reactor in a rotating oscillating state. The periodically changing electric field stimulates the growth of capacitive microorganisms, improving biofilm mass transfer efficiency and enhancing the activity of electroactive microorganisms. This invention is suitable for high-carbon wastewater with a COD concentration of 1000–2000 mg / L, effectively improving wastewater flowability within the reactor, increasing microbial activity, and simultaneously increasing the contact area between microorganisms and wastewater, ultimately improving wastewater decarbonization efficiency.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0010] This invention relates to a rotary oscillating bioelectric reactor suitable for high-carbon wastewater treatment, comprising a reactor body, a rotary oscillating carrier, a rotary oscillating graphite plate, and a rotary oscillating actuator.

[0011] Preferably, the reactor body is a cylinder, characterized in that: from bottom to top, it consists of an inlet zone, a rotating oscillating graphite plate, a rotating oscillating carrier, and an outlet zone.

[0012] Preferably, the rotating oscillating carrier is characterized in that: the material is a metal with good electrical conductivity, preferably aluminum alloy.

[0013] Preferably, the rotating oscillating carrier is characterized by having circular mesh openings with a diameter of 3 cm, allowing sewage to pass through the mesh openings, and allowing an electroactive biofilm to be attached to it.

[0014] Preferably, the rotating oscillating carrier is characterized in that: its shape is a disc with a diameter of nine-tenths of the inner diameter of the reactor, a thickness of 2cm, and along the circumferential direction, the carrier surface is alternately provided with grooves and protrusions at intervals of 45°.

[0015] Preferably, the rotating oscillating graphite plate is characterized in that: its shape is a circle with a diameter of nine-tenths of the inner diameter of the reactor, and along the circumferential direction, the carrier surface is alternately provided with grooves and protrusions at intervals of 45°.

[0016] Preferably, the rotating oscillating carrier is connected to the positive terminal of the power supply via a wire, and the rotating oscillating graphite plate is connected to the negative terminal of the power supply via a wire.

[0017] Preferably, the rotation speed of the rotating oscillating carrier and the rotating oscillating graphite plate is 2 r / min, and the rotation directions are opposite; the oscillation stroke of the rotating oscillating carrier is from the center of the reactor to the top of the reactor, and the oscillation stroke of the rotating oscillating graphite plate is from the center of the reactor to the bottom of the reactor. The oscillation period of both is 30s, and they are located at the center of the reactor at the beginning of the first cycle, with a distance of 2cm between their centers.

[0018] This invention has the following advantages:

[0019] 1. Mitigating COD concentration differences within different micro-zones. Compared to traditional electroactive biofilms, the rotating and oscillating method thoroughly agitates high-carbon wastewater, reducing organic matter concentration differences, ensuring similar electron removal rates and small potential differences within each micro-zone, maintaining carrier electron balance, thereby improving microbial activity and treatment efficiency.

[0020] 2. Enhance microbial activity. The combination of a rotating oscillating carrier and a rotating oscillating graphite plate creates a changing electric field on their uneven surfaces during rotation, resulting in a periodically changing current. This optimized power supply mode is more conducive to the expression of active enzymes and the increase of active sites in electroactive microorganisms, promoting microbial metabolism, stimulating their electron transport system, and thus enhancing the overall activity of the microorganisms.

[0021] 3. Increase the contact area between microorganisms and organic matter. The rotating oscillating carrier has mesh holes, which expands the attachment area of ​​the electroactive biofilm. More electroactive microorganisms can be accommodated in the same volume of reactor. At the same time, the contact area between the electroactive biofilm and organic matter is increased, improving the overall efficiency of organic matter transport to the biofilm and improving the overall decarbonization efficiency of microorganisms. Attached Figure Description

[0022] Figure 1 This is a rotating oscillating bioelectric reactor suitable for treating high-carbon wastewater.

[0023] Figure 2 The carrier used in this invention is a rotating oscillating carrier.

[0024] Figure 3 This is a flowchart illustrating the operation of the present invention.

[0025] Figure 4 This is a schematic diagram of the device of the present invention.

[0026] Figure 5 This is the current density diagram from Example 1.

[0027] Figure 6 The diagram shows the operation of the apparatus in experimental groups 1 and 2 in Example 2.

[0028] Figure 7 The bar chart shows the electron utilization rate in each embodiment.

[0029] in:

[0030] 1. Inlet; 2. Rotary vibrating graphite plate; 3. Rotary vibrating carrier; 4. Outlet; 5. Rotary vibrating actuator; 6. Reactor outer wall; 7. Rotary vibrating drive rod

[0031] 31. Protrusion; 32. Groove; 33. Round hole Detailed Implementation

[0032] The invention will now be explained in detail with reference to the illustrations and specific implementation schemes.

[0033] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0034] The high-carbon wastewater treatment in the reactor of this invention includes the following steps:

[0035] Step 1: Cultivating electroactive microbial biofilm: Add a solution containing electroactive microbial strains, vitamins, sodium acetate, and sulfate buffer to the reactor. Simultaneously start the rotary oscillator and connect the rotary oscillating carrier and the rotary oscillating graphite plate to the positive and negative terminals of the power supply, respectively, so that the biofilm can be attached to the rotary oscillating carrier. Control the cultivation time according to the actual needs of treating high-carbon wastewater to ensure that the biofilm attachment on the rotary oscillating carrier meets the requirements.

[0036] Step 2: Perform rotary oscillation decarburization: such as Figure 3As shown in the flowchart, 1 represents the same groove and 2 represents the same protrusion. Wastewater enters the reactor through the inlet and the rotary oscillating actuator is activated, causing the rotary oscillating carrier and the rotary oscillating graphite plate to rotate and oscillate, stirring up the organic matter in the water and making the concentration of organic matter tend to be uniform. During this process, the electroactive biofilm on the carrier comes into continuous contact with the organic matter. The electroactive microorganisms decompose the organic matter into electrons and CO2. The electrons are directly connected to the positive electrode through the wires connected to the rotary oscillating carrier.

[0037] The reactions of electroactive biomembranes with organic matter on the surface of a rotating oscillating carrier are shown below.

[0038] Organic matter -e - →H + +CO2

[0039] Step 3: Complete the microbial reaction: Electrons on the rotating carrier are transferred to the cathode through the power supply voltage. The cathode is connected to the rotating graphite plate, where water is generated by the reaction. The treated wastewater is then discharged from the outlet.

[0040] The reaction at the rotating, oscillating graphite plate is shown below.

[0041] H + +O2+e - →H20

[0042] like Figure 4 The schematic diagram illustrates the electrochemical reaction principle described in steps 2 and 3.

[0043] Example 1: Treatment of Municipal Solid Waste Leachate

[0044] The COD concentration of the influent to the landfill leachate treatment plant is about 1000 mg / L. Part of the leachate is introduced into the reactor, which has an inner diameter of 3m and an inner height of 3m. The rotating oscillating carrier and the rotating oscillating graphite plate have a radius of 2.7m and a thickness of 3cm.

[0045] (1) Cultivate electroactive microbial biofilms on a rotating oscillating carrier.

[0046] (2) Start the rotary oscillating actuator to agitate and circulate the water. Turn on the circuit to initiate the reaction. After 3 hours in the reactor, measure the current density at a point on the rotary oscillating carrier. The results are as follows: Figure 5 As shown.

[0047] (3) The COD concentration of the effluent is shown in Table 1. It meets the Class B standard and is more efficient than the traditional method.

[0048] Table 1 Comparison of Wastewater Treatment Data

[0049]

[0050] Example 2: Municipal Wastewater Treatment

[0051] In the long-term operation of wastewater treatment plants treating high-carbon wastewater, traditional electroactive biofilm devices cannot provide a growth environment with periodically changing electric fields for microorganisms, thus causing microbial activity to decline over time. This invention uses rotational oscillation to create a periodically changing electric field, providing a periodically varying current, thereby efficiently maintaining microbial activity.

[0052] Using a traditional electroactive biomembrane system as the control group, experimental group 1 consisted of a carrier and graphite plate that remained stationary during oscillation, while experimental group 2 consisted of a carrier and graphite plate that rotated during oscillation within the same reactor. Figure 6 As shown in Table 2, the same vitamins, sodium acetate, sulfate buffer, and solutions containing electroactive microbial strains were added to all three reactors. After 10 days of culture, metagenomic sequencing of the microorganisms was performed, and wastewater with a COD concentration of 2000 mg / L was introduced for treatment. Metagenomic sequencing of the microorganisms was performed on days 40 and 70, respectively. The microbial sequencing results are shown in Table 2. Comparing the data in Table 2, it can be found that before wastewater treatment, the number of microbial species in the three reactors was similar. After a short period of wastewater treatment, the number of microbial species in all three reactors decreased to some extent, with a more significant decrease in the control group and the smallest decrease in experimental group 2. After a long period of wastewater treatment, the number of microbial species in the control group decreased significantly, the number of microbial species in experimental group 1 decreased slightly, and the number of microbial species in experimental group 2 decreased slightly. This indicates that the carrier in this invention can carry a larger number of electroactive microorganisms, thereby enhancing the anti-interference ability and helping to maintain the species count. Simultaneously, the periodic change in the electric field created by rotational oscillation further enhances species diversity, maintaining a near-initial operating state.

[0053] Table 2 Microbial metagenomic sequencing data

[0054]

[0055] Example 3: Water treatment when there are large instantaneous changes in COD load

[0056] In Example 1, situations often arise where the instantaneous COD load of wastewater fluctuates greatly, resulting in uneven water quality. Faced with such conditions, biofilms often cannot adapt quickly enough. Excessively high or low organic matter concentrations can lead to either slow decomposition of organic matter or insufficient nutrients, thus reducing removal efficiency. This invention uses a rotating and oscillating method to agitate the wastewater, stabilizing the organic matter concentration and ensuring treatment efficiency.

[0057] For the apparatus in Example 1, wastewater with COD concentrations of 1000 mg / L, 1500 mg / L, and 2000 mg / L was introduced sequentially, with each wastewater sample representing 1 / 3 of the reactor volume. The control group was the one without the rotating oscillating actuator activated, while the experimental group was the one with the rotating oscillating actuator activated. Random samples were taken for analysis after a 6-hour hydraulic retention period. The analysis results are shown in Table 3.

[0058] Table 3 Wastewater COD Concentration Data

[0059]

[0060] The electron utilization efficiency of the above three embodiments was verified by calculation, and the formula is as follows:

[0061]

[0062] N 外 =IT (2)

[0063]

[0064] Where, N 内 This indicates the amount of electrons (C) removed from organic matter by electroactive microorganisms inside the reactor; N 电 The charge of 1 mol of electrons (C / mol) is taken as 96485 C / mol; q represents the COD concentration of wastewater (g / L); V represents the volume of wastewater in the reactor (L), taken as 76400L here; N represents the number of electrons (mol) required for 1 mol of O2 to participate in the reaction, which is 4 mol; M represents the molar mass of oxygen (g / mol), which is 32 g / mol; N 外 C is the amount of electrons (C) that travel from inside the reactor to the power source via a wire; I is the current intensity (A); T is the reaction time (s); and n is the electron utilization efficiency.

[0065] The calculation results are shown in Table 4, and a bar chart of electron utilization efficiency is plotted based on the results. Figure 7 As shown.

[0066] Table 4. Calculation of electron utilization efficiency for Examples 1, 2, and 3.

[0067]

[0068] like Figure 7 As shown, the electron utilization rate of this invention during normal operation is much higher than that of traditional devices. That is, most of the electrons removed from the carrier can be transmitted to the graphite plate through wires and power supply, highlighting the advantage of this device in efficient electron utilization.

[0069] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A rotary oscillating bioelectric reactor suitable for treating high-carbon wastewater, characterized in that: The reactor comprises a reactor body, a rotating oscillating carrier, a rotating oscillating graphite plate, and a rotating oscillating actuator. The rotating oscillating carrier is made of a highly conductive metal and is connected to the anode of a power source via wires. The rotating oscillating carrier has circular mesh openings with a diameter of 3 cm, through which wastewater passes, and an electroactive biofilm adheres. The rotating oscillating carrier is shaped like a disc with a diameter nine-tenths of the reactor's inner diameter and a thickness of 2 cm. Along the circumference, the carrier surface alternates between grooves and convex surfaces at 45° intervals. The rotating oscillating graphite plate is made of graphite and is circular in shape with a diameter nine-tenths of the reactor's inner diameter. Along the circumference, the carrier surface alternates between grooves and convex surfaces at 45° intervals and is connected to the cathode of a power source via wires.

2. The rotary oscillating bioelectric reactor for high-carbon wastewater treatment according to claim 1, characterized in that: The reactor is cylindrical, and from bottom to top are the inlet zone, rotating oscillating graphite plate, rotating oscillating carrier, and outlet zone.

3. The rotary oscillating bioelectric reactor for treating high-carbon wastewater according to claim 1, characterized in that: The rotating oscillation carrier is made of aluminum alloy.

4. The rotary oscillating bioelectric reactor for treating high-carbon wastewater according to claim 1, characterized in that: It enables the rotating oscillating carrier and the rotating oscillating graphite plate to rotate at a speed of 2r / min, with opposite rotation directions; the oscillation stroke of the rotating oscillating carrier is from the center of the reactor to the top of the reactor, and the oscillation stroke of the rotating oscillating graphite plate is from the center of the reactor to the bottom of the reactor. The oscillation period of both is 30s, and they are located at the center of the reactor at the beginning of the first cycle, with a distance of 2cm between their centers.

5. The method of using the rotary oscillating bioelectric reactor for high-carbon wastewater treatment according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Cultivating electroactive microbial biofilm: Add a solution containing electroactive microbial strains, vitamins, sodium acetate and sulfate buffer to the reactor. Start the rotary oscillator and connect the rotary oscillating carrier and the rotary oscillating graphite plate to the positive and negative terminals of the power supply respectively. Cultivate for 6 hours to allow the biofilm to form on the rotary oscillating carrier. Step 2: Perform rotary oscillation decarbonization: Wastewater enters the reactor through the inlet. The rotary oscillation drive is started, causing the rotary oscillation carrier and the rotary oscillation graphite plate to rotate and oscillate, stirring up the organic matter in the water and making the concentration of organic matter tend to be uniform. During this process, the electroactive biofilm on the carrier comes into continuous contact with the organic matter. The electroactive microorganisms decompose the organic matter into electrons and CO2. The electrons are directly connected to the positive electrode through the wires connected to the rotary oscillation carrier. Step 3: Complete the microbial reaction: Electrons on the rotating carrier are transferred to the cathode through voltage. The cathode is connected to the rotating graphite plate, where water is generated. The treated wastewater is then discharged from the outlet.

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