An industrial wastewater treatment device based on bioelectrochemical catalytic degradation method

Abstract

This utility model belongs to the field of industrial wastewater treatment technology, specifically relating to an industrial wastewater treatment device based on bioelectrochemical catalytic degradation. The device includes a reaction vessel with an air inlet, a wastewater inlet, a feed inlet, a thermometer, an exhaust port, a stirrer, electrodes, sensors, an intelligent control module, and an exhaust port. The air inlet is for gas input; the wastewater inlet is for wastewater input; the feed inlet is for adding bacterial cultures, electron donors, and photocatalytic carriers; the thermometer is fixedly connected inside the reaction vessel and has a built-in temperature compensation unit electrically connected to a heat dissipation device, which is fixedly connected to the reaction vessel; the exhaust port is fixedly connected to the upper side of the reaction vessel and is connected to a pressure regulating module; the stirrer is installed on the lower side inside the reaction vessel. This utility model can effectively remove heavy metals, reduce emission pollution, and solve the problem of mixed pollution.

Description

Technical Field

[0001] This utility model belongs to the field of industrial wastewater treatment technology, specifically relating to an industrial wastewater treatment device based on bioelectrochemical catalytic degradation. Background Technology

[0002] In industrial production, wastewater discharged from industries such as electroplating, chemicals, and metallurgy often contains recalcitrant macromolecules such as benzene ring organic compounds and long-chain hydrocarbons, as well as Cr(VI) and Cd. 2+ The presence of toxic heavy metal ions forms a highly polluted, low-biodegradability mixed wastewater.

[0003] Traditional biological methods rely on naturally acclimatized microbial communities and have high requirements for biodegradability (BOD / COD needs to be >0.3). However, the BOD / COD in mixed wastewater is often below 0.2, making it difficult for microorganisms to directly degrade it. Additional carbon sources need to be added, which is not economically viable.

[0004] Chemical precipitation methods (such as hydroxide precipitation) require strict pH conditions (such as pH > 8.5 for Cr(VI) precipitation), which can easily cause scaling in pipes and generate a large amount of heavy metal sludge, resulting in high subsequent treatment costs. Utility Model Content

[0005] The purpose of this invention is to provide an industrial wastewater treatment device based on bioelectrochemical catalytic degradation, which can effectively remove heavy metals, reduce emissions pollution, and solve the problem of mixed pollution.

[0006] The specific technical solution adopted by this utility model is as follows:

[0007] An industrial wastewater treatment device based on bioelectrochemical catalytic degradation includes a reaction vessel, on which are provided:

[0008] An air inlet is fixedly connected to the upper side of the reaction vessel for inputting gas.

[0009] Wastewater inlet, which is fixedly connected to the lower end of the outside of the reaction vessel, is used for the input of wastewater;

[0010] The inlet is fixedly connected to the upper side of the reaction vessel and is used to inoculate the microbial strain, electron donor, and photocatalytic carrier.

[0011] A thermometer is fixedly connected inside the reaction vessel, and the thermometer has a built-in temperature compensation unit. The temperature compensation unit is electrically connected to a heat dissipation device, and the heat dissipation device is fixedly connected to the reaction vessel.

[0012] An exhaust port is fixedly connected to the upper side of the reaction vessel and is connected to a pressure regulating module.

[0013] A stirrer is installed on the lower side inside the reaction vessel;

[0014] An electrode is fixedly connected to the lower side inside the reaction vessel. The reaction vessel includes an anode and a cathode. The anode is biochar-supported nano-zero-valent iron, and the cathode is a biofilm-embedded hexavalent chromium ion-reducing bacterium.

[0015] The sensors include an ORP sensor, a Cr(VI) concentration sensor, a DO sensor, and a pH sensor installed inside the reaction vessel.

[0016] The intelligent control module is electrically connected to the ORP sensor, Cr(VI) concentration sensor, DO sensor, and pH sensor.

[0017] The discharge port is fixedly connected to the lower end of the outside of the reaction vessel.

[0018] Furthermore, a flow control valve or a mass flow meter is provided on the air inlet.

[0019] Furthermore, the bacterial strains are Shewanella oneidensis and Bacillus subtilis.

[0020] Furthermore, the electron donor is sodium acetate.

[0021] Furthermore, the photocatalytic support comprises a substrate, an inner layer, and an outer layer. The substrate is a polyvinylidene fluoride hollow fiber membrane, the inner layer is a TiO2 / graphene photocatalytic layer prepared by electrospinning, and the outer layer is a sodium alginate-chitosan microcapsule encapsulating degrading bacteria.

[0022] Furthermore, the thickness of the TiO2 / graphene photocatalytic layer is 50-100 nm.

[0023] Furthermore, the pressure regulating module includes a gas buffer tank and a back pressure valve, wherein the gas buffer tank is connected to the exhaust port through the back pressure valve.

[0024] The technical effects achieved by this utility model are as follows:

[0025] This invention discloses an industrial wastewater treatment device based on bioelectrochemical catalytic degradation. Through a three-stage process gradient purification involving pretreatment, main treatment, and advanced treatment, it can effectively remove heavy metals, reduce emission pollution, and solve the problem of mixed pollution. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] The attached diagram lists the components represented by each number as follows:

[0028] 1. Air inlet; 2. Wastewater inlet; 3. Discharge port; 4. Thermometer; 5. Exhaust port; 6. Stirrer; 7. Electrode; 8. ORP sensor; 9. Discharge port; 10. Photocatalytic carrier; 11. Cr(VI) concentration sensor; 12. DO sensor; 13. pH sensor; 14. Intelligent control module; 15. Heat dissipation device; 16. Gas buffer tank; 17. Back pressure valve; 18. Reaction vessel. Detailed Implementation

[0029] To make the objectives and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of this utility model and does not strictly limit the scope of protection specifically claimed by this utility model.

[0030] like Figure 1 As shown, an industrial wastewater treatment device based on bioelectrochemical catalytic degradation includes a reaction vessel 18, on which:

[0031] Inlet 1 is fixedly connected to the upper side of the reaction vessel 18 and is used for gas input. By precisely controlling the gas input rate, the optimal control of process parameters can be achieved.

[0032] The inlet 1 can be equipped with a flow control valve or a mass flow meter to precisely control the gas input rate.

[0033] Wastewater inlet 2 is fixedly connected to the lower end of the outside of the reaction vessel 18. The wastewater inlet 2 connects the wastewater input area and the reaction vessel 18 and is used for the input of wastewater.

[0034] Inlet 3 is fixedly connected to the upper side of the reaction vessel 18 and is used to inoculate the bacterial strain, electron donor and photocatalytic carrier 10.

[0035] Among them, the bacterial species were Shewanella oneidensis (a heterotrophic metal-reducing bacterium) and Bacillus subtilis (a bacterium that secretes reducing extracellular polymers);

[0036] The electron donor is sodium acetate;

[0037] The photocatalytic carrier 10 includes a substrate, an inner layer, and an outer layer. The substrate is a polyvinylidene fluoride (PVDF) hollow fiber membrane, the inner layer is a TiO2 / graphene photocatalytic layer (thickness 50-100nm) prepared by electrospinning, and the outer layer is a sodium alginate-chitosan microcapsule encapsulating degrading bacteria.

[0038] Thermometer 4 is fixedly connected inside the reaction vessel 18, and the thermometer 4 has a built-in temperature compensation unit. The temperature compensation unit is electrically connected to a heat dissipation device, which is fixedly connected to the reaction vessel 18. When the temperature detected by the thermometer 4 exceeds the set threshold, the heat dissipation device is automatically activated through the temperature compensation unit to ensure that the processing environment temperature is always lower than the microbial tolerance limit temperature.

[0039] Exhaust port 5 is fixedly connected to the upper side of reaction vessel 18. Exhaust port 5 is connected to a pressure regulating module. The pressure regulating module includes a gas buffer tank 16 and a back pressure valve 17. The gas buffer tank 16 is connected to exhaust port 5 through back pressure valve 17.

[0040] The back pressure valve 17 is controlled based on PID (Proportional-Integral-Derivative Control) to monitor the pressure of the reaction system in real time, automatically discharge excess gas, and maintain the pressure within a certain range.

[0041] A stirrer 6 is installed on the lower side inside the reaction vessel 18. The stirrer 6 integrates a pulsed reducing agent dosing device and an ultrasonic cavitation device. Through the synergistic effect of pulsed reducing agent dosing and ultrasonic cavitation, the liquid phase mass transfer coefficient is improved, and the complete reduction of Cr(VI) is achieved.

[0042] Electrode 7 is fixedly connected to the lower side inside the reaction vessel 18. The reaction vessel 18 includes an anode and a cathode. The anode is biochar-supported nano-zero-valent iron (nZVI) to accelerate electron transfer, and the cathode is a biofilm-embedded Cr(VI)-reducing bacteria.

[0043] Chromium can be recovered by electrolysis (cathode deposition) through nano-zero valent iron (nZVI) supported on biochar and Cr(VI)-reducing bacteria embedded in biofilm. This is the primary pretreatment: electro-Fenton coupled bio-enzyme catalysis (laccase / peroxidase) to break down macromolecular chains.

[0044] The sensors include an ORP sensor 8, a Cr(VI) concentration sensor 11, a DO sensor 12, and a pH sensor 13.

[0045] The ORP sensor 8 is installed near the electrode 7 to control the reduction endpoint (such as ORP > 500mV in the electro-Fenton reaction) and to monitor the electrochemical reaction potential in real time.

[0046] The Cr(VI) concentration sensor 11 is installed inside the reaction vessel 18 near the discharge port 9. The Cr(VI) concentration sensor 11 adopts the diphenylcarbazide spectrophotometric method (GB 7467-87).

[0047] The DO sensor 12 is installed in the middle of the inside of the reaction vessel 18. The DO sensor 12 is used to monitor dissolved oxygen (DO) to adjust the aeration rate and ensure the optimal living environment for microorganisms (pH 6.5-7.5, DO 3-4 mg / L).

[0048] pH sensor 13 is installed in the middle of the reaction vessel 18. pH sensor 13 is used to monitor pH value to automatically add alkali (NaHCO3) to ensure the optimal survival environment for microorganisms (pH 6.5-7.5, DO 3-4 mg / L).

[0049] The intelligent control module 14 can be fixedly connected to the outside of the reaction vessel 18. The ORP sensor 8, Cr(VI) concentration sensor 11, DO sensor 12 and pH sensor 13 are all electrically connected to the intelligent control module 14. Based on the feedback system of the ORP sensor 8, Cr(VI) concentration sensor 11, DO sensor 12 and pH sensor 13, the hydraulic retention time (HRT), aeration intensity and electrochemical unit current density are dynamically adjusted.

[0050] Discharge port 9 is fixedly connected to the lower end of the outside of the reaction vessel 18 and is used to discharge treated wastewater.

[0051] The method of using this utility model includes the following steps:

[0052] Phase 1: Pretreatment Phase (Electro-Fenton Coupled Bioenzyme Catalysis)

[0053] Objective: To break down large organic molecules and improve the biodegradability of wastewater.

[0054] Detailed operation steps:

[0055] Wastewater conditioning: COD, pH, Cr(VI) concentration, etc. of the influent are detected by ORP sensor 8, Cr(VI) concentration sensor 11, DO sensor 12 and pH sensor 13, and the pH is adjusted to 3.0-3.5 (by adding H2SO4 through the acidification system).

[0056] Electro-Fenton reaction: H2O2 (200 mg / L) and FeSO4 (molar ratio H2O2:Fe) were added to reaction vessel 18. 2+ =3:1), start electrode 7, current density 15mA / cm2, reaction time 30min, ORP controlled at >500mV.

[0057] Bio-enzyme catalysis: Add laccase (500 U / L) and peroxidase (300 U / L), maintain the temperature at 30±2℃ (temperature controlled by heating plate), and aeration rate of 0.5 m3 / min (DO maintained at 2-3 mg / L).

[0058] Output indicators: COD decreases by ≥35%, and the BOD / COD ratio increases from 0.2 to 0.5.

[0059] Phase Two: Main Processing Phase

[0060] Objective: To deeply degrade organic matter and simultaneously remove heavy metals.

[0061] Operating steps:

[0062] Membrane module startup

[0063] The pretreated wastewater is pumped into the photocatalytic carrier 10, and the ultraviolet LED array (wavelength 365nm, intensity 10W / m²) is turned on. 2 (Irradiation interval 5 minutes / session)

[0064] Biocatalytic operation: hydraulic load controlled at 2.5m 3 / (m 2 •d) Maintain membrane flux at 15 LMH and add immobilized Pseudomonas bacteria (biomass ≥ 5000 mg / L);

[0065] Backwashing cycle: Every 2 hours, combined air and water backwashing (air pressure 0.2MPa, water flow rate 1.5m / s).

[0066] Real-time control: Automatically adds alkali (NaHCO3 solution) based on pH sensor 13 (set range 6.5-7.5), and adjusts the aeration rate (maintaining DO = 3-4 mg / L) via DO sensor.

[0067] Output indicators: COD < 300 mg / L, heavy metals (such as Cd) 2+ Removal rate > 90%

[0068] Phase Three: Deep Treatment Phase (Algae-Fungus Symbiotic System)

[0069] Objective: To remove residual pollutants and denitrify and remove phosphorus.

[0070] Operating steps:

[0071] Algae and bacteria culture: Inoculated with Chlorella vulgaris and Nitrosomonas, light intensity 8000 lux (LED white light, light-dark ratio 12h:12h).

[0072] System operation: Hydraulic retention time (HRT) = 24h, carbon source supplementation (sodium acetate) control C:N:P = 100:5:1, regular harvesting of algal biomass (30% of algae harvested weekly);

[0073] Output parameters: TN < 15 mg / L, TP < 0.5 mg / L, Cr(VI) < 0.05 mg / L.

[0074] In summary, this technical solution can effectively remove heavy metals, reduce emissions, and solve the problem of mixed pollution through a three-stage process gradient purification involving pretreatment, main treatment, and advanced treatment.

[0075] Pretreatment: Electro-Fenton coupled bio-enzyme catalysis (laccase / peroxidase) is the first to combine electrochemical oxidation with bio-enzyme catalysis, which specifically breaks down large organic molecules (such as benzene rings and long-chain hydrocarbons), increasing BOD / COD from 0.2 to 0.5 (compared to only 0.3-0.4 by traditional methods), thus paving the way for subsequent biological treatment;

[0076] Main treatment: Composite biocatalytic membrane reactor (PVDF hollow fiber membrane supported on TiO2 / graphene photocatalytic layer + immobilized Pseudomonas bacteria) to achieve photocatalysis (UV LED excitation) and biodegradation "light-bacteria synergy", COD <300mg / L, heavy metal removal rate >90%, 30% higher efficiency than single membrane treatment;

[0077] Advanced treatment: Algae-bacteria symbiotic system (Chlorella + nitrifying bacteria) simultaneously removes nitrogen and phosphorus (TN < 15 mg / L, TP < 0.5 mg / L) through photosynthesis and biological nitrification and denitrification, and can recover algal biomass (30% harvested weekly), taking into account both pollution control and resource utilization.

[0078] The above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. Structures, devices, and operating methods not specifically described or explained in this utility model, unless otherwise specified or limited, shall be implemented using conventional methods in the field.

Claims

1. An industrial wastewater treatment device based on bioelectrochemical catalytic degradation, characterized in that: Includes a reaction vessel (18), on which are provided: Air inlet (1), which is fixedly connected to the upper side of the reaction vessel (18) for the input of gas; Wastewater inlet (2), which is fixedly connected to the lower end of the outside of the reaction vessel (18) for the input of wastewater; The inlet (3) is fixedly connected to the upper side of the reaction vessel (18) and is used to inoculate the bacterial strain, electron donor and photocatalytic carrier (10); The thermometer (4) is fixedly connected inside the reaction vessel (18), and the thermometer (4) has a built-in temperature compensation unit. The temperature compensation unit is electrically connected to a heat dissipation device, which is fixedly connected to the reaction vessel (18). The exhaust port (5) is fixedly connected to the upper side of the reaction vessel (18), and the exhaust port (5) is connected to a pressure regulating module; A stirrer (6) is installed on the lower side inside the reaction vessel (18); Electrode (7), the electrode (7) is fixedly connected to the lower side inside the reaction vessel (18), the reaction vessel (18) includes an anode and a cathode, the anode is biochar-supported nano-zero valent iron, and the cathode is biofilm-embedded hexavalent chromium ion reducing bacteria; The sensors include an ORP sensor (8), a Cr(VI) concentration sensor (11), a DO sensor (12), and a pH sensor (13) installed inside the reaction vessel (18); The intelligent control module (14) is electrically connected to the ORP sensor (8), Cr(VI) concentration sensor (11), DO sensor (12) and pH sensor (13). The discharge port (9) is fixedly connected to the lower end of the outside of the reaction vessel (18).

2. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 1, characterized in that: The air inlet (1) is equipped with a flow control valve or a mass flow meter.

3. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 1, characterized in that: The bacterial strains are Shewanella oneidensis and Bacillus subtilis.

4. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 1, characterized in that: The electron donor is sodium acetate.

5. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 1, characterized in that: The photocatalytic carrier (10) includes a substrate, an inner layer and an outer layer. The substrate is a polyvinylidene fluoride hollow fiber membrane, the inner layer is a TiO2 / graphene photocatalytic layer prepared by electrospinning, and the outer layer is a sodium alginate-chitosan microcapsule encapsulating degrading bacteria.

6. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 5, characterized in that: The thickness of the TiO2 / graphene photocatalytic layer is 50-100 nm.

7. The industrial wastewater treatment device based on bioelectrochemical catalytic degradation method according to claim 1, characterized in that: The pressure regulating module includes a gas buffer tank (16) and a back pressure valve (17), and the gas buffer tank (16) is connected to the exhaust port (5) through the back pressure valve (17).

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