A graphene oxide-enhanced membrane bioreactor and wastewater treatment method

Abstract

The present invention provides a graphene oxide-enhanced membrane bioreactor and a wastewater treatment method, relating to the technical field of wastewater treatment. The reactor includes a controller, an inlet tank, a GO pretreatment column, an MBR reaction tank, a membrane assembly, a first inlet pump, a first return pump, and a second inlet pump; the inlet end of the first inlet pump is connected to the inlet tank, and the outlet end of the first inlet pump is connected to the GO pretreatment column; the inlet end of the first return pump is connected to the GO pretreatment column, and the outlet end of the first return pump is connected to the inlet tank; the inlet end of the second inlet pump is connected to the GO pretreatment column, and the outlet end of the first return pump is connected to the inlet tank; the inlet end of the second inlet pump is connected to the GO pretreatment column, and the outlet end of the second inlet pump is connected to the MBR reaction tank; the membrane assembly is disposed in the MBR reaction tank; and the controller is connected to the first inlet pump, the second inlet pump, and the first return pump, respectively. The reactor can achieve efficient treatment of mining wastewater and fully meet the requirements of wastewater treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to a graphene oxide reinforced membrane bioreactor and a wastewater treatment method. Background Art

[0002] The treatment and reuse of contaminated mining water is a widespread concern within the mining industry. The volatile water quality of mining water, particularly water bodies high in toxic substances, makes conventional water treatment methods difficult to address. Membrane bioreactors (MBRs) are a combined process system that combines biological treatment with membrane separation. Currently, MBRs are being used to effectively filter and treat contaminated mining water. However, current MBRs offer suboptimal filtration performance and are inefficient for treating heavy metal-containing wastewater in mining areas, making them difficult to meet the needs of mining wastewater treatment. The use of new MBRs to efficiently treat mining wastewater is becoming an increasingly prominent research area.

[0003] Therefore, designing a graphene oxide enhanced membrane bioreactor and wastewater treatment method that can achieve efficient treatment of mining wastewater and fully meet the use needs of sewage treatment is an urgent problem to be solved. Summary of the Invention

[0004] Based on this, the present invention aims to overcome the defects of the prior art and provide a graphene oxide reinforced membrane bioreactor to pre-treat sewage by establishing a GO (graphene oxide) pre-treatment column. The high specific surface area, toughness, adsorption capacity and interaction between functional groups of GO can efficiently adsorb heavy metals in sewage, and can achieve effective mixing and preliminary reaction of sewage and treatment materials in the pre-treatment stage, providing a material basis for subsequent deep treatment. At the same time, the biological filtration treatment of the MBR reaction tank can fully remove pollutants in sewage, and due to the sufficient and uniform mixing of sewage, it can efficiently achieve the interception, degradation and other purification effects of pollutants in sewage, forming a process system for efficiently treating heavy metal sewage, and achieving efficient treatment of heavy metal sewage. In addition, since the treatment material is easy to obtain and has a long-term and stable existence, it can continuously and effectively purify sewage for a long time, meeting the production demand for heavy metal sewage treatment.

[0005] The present invention also provides a wastewater treatment method, which performs a preliminary filtration treatment of large particles of heavy metal wastewater through water inlet filtration treatment, and then performs a pretreatment mixing treatment in which the wastewater and GO are fully mixed and filtered to form a biological mixed liquid, and then the filtration conditions are reasonably adjusted under the MBR membrane reaction to achieve a wastewater treatment effect that meets the requirements of efficient treatment. Since the filtration conditions can be adjusted in real time as needed, the different usage requirements of wastewater treatment can be fully met. In addition, by monitoring the permeability of the filter membrane to control the backwash system to perform timely backwashing of the membrane assembly, it can effectively avoid the situation where the membrane assembly is blocked and the filtration efficiency is reduced, ensuring that the entire graphene oxide enhanced membrane bioreactor can treat the metal wastewater in a long-term and efficient manner, fully meeting the needs of heavy metal wastewater treatment.

[0006] The first technical solution provided by the present invention is:

[0007] A graphene oxide enhanced membrane bioreactor comprises a controller, an inlet tank, a GO pretreatment column, an MBR reaction tank, a membrane assembly, a first inlet pump, a first return pump and a second inlet pump; the inlet end of the first inlet pump is connected to the inlet tank, and the outlet end of the first inlet pump is connected to the GO pretreatment column; the inlet end of the first return pump is connected to the GO pretreatment column, and the outlet end of the first return pump is connected to the inlet tank; the inlet end of the second inlet pump is connected to the GO pretreatment column, and the outlet end of the first return pump is connected to the MBR reaction tank; the membrane assembly is arranged in the MBR reaction tank; the controller is respectively connected to the first inlet pump, the second inlet pump and the first return pump; an inwardly rotating guide plate is provided in the GO pretreatment column, and the outlet direction of the first inlet pump is opposite to the optional installation direction of the guide plate; the membrane assembly is coaxially arranged with the MBR reaction tank and located in the central area of the MBR reaction tank.

[0008] Furthermore, it also includes a temperature controller and a first agitator; the temperature controller is connected to the GO pretreatment column; the first agitator is arranged in the MBR reaction tank; and the controller is connected to the temperature controller and the first agitator respectively.

[0009] Furthermore, it also includes a blower and an aeration pipe; one end of the aeration pipe is arranged in the MBR reaction tank and close to the membrane assembly, and the other end of the aeration pipe is connected to the blower; and the controller is connected to the blower.

[0010] Furthermore, it also includes a first backwash pump and a second backwash pump; the water outlet of the first backwash pump is connected to the external filtration space of the membrane assembly, and the water inlet of the second backwash pump is connected to the internal filtration space of the membrane assembly.

[0011] The second technical solution provided by the present invention is:

[0012] A wastewater treatment method is applied to the graphene oxide reinforced membrane bioreactor described in the first technical solution, comprising obtaining a filtration start signal, forming a first water inlet instruction, and sending the first water inlet instruction to perform water inlet filtration processing; obtaining a water level signal, forming a first mixing instruction according to the water level signal, and performing pretreatment mixing processing according to the first mixing instruction; obtaining first concentration data, forming a deep mixing processing instruction according to the first concentration data, and stopping the pretreatment mixing processing according to the deep mixing processing instruction to perform deep mixing processing; collecting deep processing temperature data, deep processing dissolved oxygen data, and deep processing pH data within a deep mixing processing cycle, and adjusting the treatment effect according to the deep processing temperature data, deep processing dissolved oxygen data, and deep processing pH data.

[0013] Furthermore, pretreatment mixing treatment is performed according to the first mixing instruction, including: starting the first water inlet pump and the first return water pump to circulate sewage, and adding adaptive microorganisms for mixing to form pretreated mixed sewage; collecting temperature data of the pretreated mixed sewage during the first pretreatment cycle, and controlling the temperature of the pretreated mixed sewage according to the temperature data; collecting sludge concentration data of the pretreated mixed sewage during the first pretreatment cycle to form first concentration data, and judging whether to form a deep mixing treatment instruction based on the first concentration data.

[0014] Furthermore, the pretreatment mixing process is stopped according to the deep mixing process instruction, and the deep mixing process is performed, including: turning off the first water inlet pump and the first return water pump, and turning on the second water inlet pump, introducing the pretreated mixed sewage into the MBR reaction tank, and adding a first amount of powdered GO to the MBR reaction tank; collecting GO concentration data within the first deep treatment cycle to form second concentration data; obtaining the second concentration data, and performing the following judgment operation based on the second concentration data: when the second concentration data is less than the GO concentration threshold, adding the second amount of powdered GO; when the second concentration data is not less than the GO concentration threshold, stopping the addition of the second amount of powdered GO.

[0015] Furthermore, a membrane permeability value is obtained, and a cleaning operation is performed according to the membrane permeability value, including collecting the membrane permeability value in the first cleaning cycle, and performing the following cleaning judgment based on the membrane permeability value: when the membrane permeability value is greater than the membrane permeability threshold, continuing to collect membrane permeability values according to the first cleaning cycle for comparison and judgment; when the membrane permeability value is not greater than the membrane permeability threshold, emptying the MBR reaction tank, performing a backwash operation, and obtaining the membrane permeability value after the operation and comparing it with the membrane permeability threshold: if the membrane permeability value is greater than the membrane permeability threshold, stopping the backwash operation; if the membrane permeability value is not greater than the membrane permeability threshold, continuing the backwash operation until the obtained membrane permeability value is greater than the membrane permeability threshold.

[0016] Furthermore, when the membrane permeability value is not greater than the membrane permeability threshold, the MBR reaction tank is drained and a backwash operation is performed, including: closing the second water inlet pump and draining the MBR reaction tank; starting the first backwash pump and the second backwash pump for initial flushing; closing the first backwash pump and the second backwash pump, and adding cleaning liquid to the MBR reaction tank for soaking; draining the cleaning liquid, and starting the first backwash pump and the second backwash pump for multiple final flushes.

[0017] The beneficial effects of the present invention are:

[0018] The graphene oxide-enhanced membrane bioreactor pre-treats wastewater by establishing a GO (graphene oxide) pre-treatment column. GO's high specific surface area, toughness, adsorption capacity, and the interaction between functional groups enable efficient adsorption of heavy metals in wastewater. Effective mixing and initial reaction between wastewater and treatment materials can be achieved during the pre-treatment stage, providing a material basis for subsequent deep treatment. At the same time, the biological filtration treatment of the MBR reaction tank can fully remove pollutants from wastewater. Furthermore, due to the fully and evenly mixed sewage, pollutants in the sewage can be efficiently intercepted and degraded, forming a highly efficient process system for treating heavy metal wastewater, achieving efficient treatment of heavy metal wastewater. Furthermore, because the treatment materials are easily accessible and long-lasting and stable, they can continuously and effectively purify wastewater, meeting production needs for heavy metal wastewater treatment.

[0019] The wastewater treatment method uses influent filtration to perform preliminary filtration treatment on large particles of heavy metal wastewater. The pretreatment mixing treatment that follows is to fully mix and filter the wastewater with GO to form a biological mixed liquid. Then, under the MBR membrane reaction, the filtration conditions are reasonably adjusted to achieve a wastewater treatment effect that meets the requirements of efficient treatment. Since the filtration conditions can be adjusted in real time according to needs, it can fully meet the different usage requirements of wastewater treatment. In addition, the permeability of the filter membrane is monitored to control the backwash system to perform timely backwashing of the membrane assembly, which can effectively avoid the situation where the membrane assembly is blocked and the filtration efficiency is reduced, ensuring that the entire graphene oxide enhanced membrane bioreactor can treat metal wastewater efficiently and long-term, fully meeting the needs of heavy metal wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of a graphene oxide enhanced membrane bioreactor according to an embodiment of the present invention;

[0021] Figure 2 A step diagram of a wastewater treatment method according to an embodiment of the present invention;

[0022] Figure 3This is a graph of sewage water quality used in experiments of a wastewater treatment method according to an embodiment of the present invention;

[0023] Figure 4 This is the data on the effect of temperature on COD removal rate in the wastewater treatment method according to the embodiment of the present invention;

[0024] Figure 5 This is the data on the effect of dissolved oxygen on COD removal rate in the wastewater treatment method according to an embodiment of the present invention;

[0025] Figure 6 The figure shows the comparison of COD removal rates of different processes in the wastewater treatment method according to the embodiment of the present invention;

[0026] Figure 7 This is the data on the effect of temperature on NH3-N removal rate in the wastewater treatment method according to an embodiment of the present invention;

[0027] Figure 8 This is the data on the effect of dissolved oxygen on the NH3-N removal rate in the wastewater treatment method according to an embodiment of the present invention;

[0028] Figure 9 The figure shows the comparison of NH3-N removal rates by different processes in the wastewater treatment method according to the embodiment of the present invention.

[0029] Figure 10 The figure shows the comparison of turbidity removal rates of different processes in the wastewater treatment method according to the embodiment of the present invention;

[0030] Figure 11 The different processes of the wastewater treatment method in the embodiment of the present invention are 2+ Comparison of removal rates

[0031] Figure 12 The membrane permeability of the membrane in different conditions in the wastewater treatment method of the embodiment of the present invention is shown.

[0032] Description of reference numerals:

[0033] 01. Water inlet tank; 02. GO pretreatment column; 21. Temperature controller; 03. MBR reaction tank; 04. Membrane assembly; 05. First water inlet pump; 06. First return water pump; 07. Second water inlet pump; 08. Controller; 91. Aeration pipe; 92. Blower; 93. First agitator; 94. First backwash pump; 95. Second backwash pump. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0037] In the description of the embodiments of the present application, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0039] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0040] The technical solution in this application will be described below with reference to the accompanying drawings.

[0041] Please refer to Figure 1, the embodiment of the present application provides a graphene oxide enhanced membrane bioreactor. The reactor improves the treatment efficiency of heavy metal wastewater by combining a new membrane bioreactor process. The graphene oxide enhanced membrane bioreactor includes a controller 08, an inlet pool 01, a GO pretreatment column 02, an MBR reaction pool 03, a membrane assembly 04, a first inlet pump 05, a first return pump 05 and a second inlet pump 07; the inlet end of the first inlet pump 05 is connected to the inlet pool 01, and the outlet end of the first inlet pump 05 is connected to the GO pretreatment column 02; the inlet end of the first return pump 05 is connected to the GO pretreatment column 02, and the outlet end of the first return pump 05 is connected to the inlet pool 01; the second inlet pump 07 The water inlet end is connected to the GO pretreatment column 02, and the water outlet end of the second water inlet pump 07 is connected to the MBR reaction tank 03; the membrane assembly 04 is arranged in the MBR reaction tank 03; the controller 08 is connected to the first water inlet pump 05, the second water inlet pump 07 and the first return water pump 05 respectively; an inward-rotating guide plate is provided in the GO pretreatment column 02, and the water outlet direction of the first water inlet pump 05 is opposite to the optional direction of the guide plate; the membrane assembly 04 is coaxially arranged with the MBR reaction tank 03 and is located in the central area of the MBR reaction tank 03.

[0042] The device pre-treats sewage by establishing a GO (graphene oxide) pre-treatment column. GO's high specific surface area, toughness, adsorption capacity, and the interaction between functional groups can efficiently adsorb heavy metals in sewage. In the pre-treatment stage, it can achieve effective mixing and preliminary reaction between sewage and treatment materials, providing a material basis for subsequent deep treatment. At the same time, the biological filtration treatment of the MBR reaction tank can fully remove pollutants in the sewage. And because the sewage is fully and evenly mixed, it can efficiently intercept and degrade pollutants in the sewage, forming a process system for efficiently treating heavy metal sewage, and achieving efficient treatment of heavy metal sewage. In addition, because the treatment materials are easy to obtain and have a long-term and stable existence, they can continuously and effectively purify sewage for a long time, meeting the production needs for heavy metal sewage treatment.

[0043] Among them, the inlet tank 01 is used to collect heavy metal wastewater and perform preliminary sedimentation and filtration. In order to ensure the effective biochemical treatment of heavy metal wastewater later, in this embodiment, a filter screen is set in the inlet tank 01 to filter out large particles in the wastewater. The heavy metal wastewater in the inlet tank 01 enters the GO (graphene oxide) pretreatment column for pretreatment through the first inlet pump 05. The heavy metal wastewater is circulated and fully mixed in the inlet tank 01 and the GO pretreatment column through the first return pump 05 to more effectively treat the pollutants in the heavy metal wastewater. After pretreatment and mixing, the heavy metal wastewater enters the MBR (enhanced membrane bioreactor) reaction tank through the second inlet pump 07 for deep treatment. In the MBR reaction tank 03, the membrane module 04 and the addition of GO powder fully cause the heavy metal wastewater to undergo physical and chemical reactions, filtering out pollutants such as heavy metals and small particles.

[0044] To enhance the effectiveness of pretreatment and advanced treatment, this embodiment also includes a temperature controller 21 and a first agitator 93. The temperature controller 21 is connected to the GO pretreatment column 02. The first agitator 93 is located within the MBR reactor 03. A controller 08 is connected to both the temperature controller 21 and the first agitator 93. The GO pretreatment column 02 performs a compression treatment on the heavy metal wastewater. In the MBR reactor 03, the density of the GO powder and microorganisms is adjusted, and the first agitator 93 continuously mixes the wastewater, effectively ensuring adequate filtration and improving the efficiency of advanced treatment.

[0045] In addition, because the microorganisms in the advanced treatment require a suitable environment to achieve efficient biochemical reactions and filter heavy metal wastewater, this embodiment also includes a blower 92 and an aeration tube 91. One end of the aeration tube 91 is located in the MBR reaction tank 03, near the membrane module 04, and the other end of the aeration tube 91 is connected to the blower 92. The controller 08 is connected to the blower 92. This provides the microorganisms with suitable environmental conditions and ensures that they are in optimal working condition.

[0046] In addition, it should be noted that the module assembly primarily serves as a physical barrier, isolating generated pollutants such as contaminants and heavy metals within the external filtration space of membrane assembly 04, allowing the filtered water to be smoothly collected after passing through the membrane body of membrane assembly 04. Therefore, prolonged use will inevitably lead to clogging of the surface of membrane assembly 04. Therefore, this embodiment also includes a first backwash pump 94 and a second backwash pump 95; the outlet of the first backwash pump 94 is connected to the external filtration space of membrane assembly 04, and the inlet of the second backwash pump 95 is connected to the internal filtration space of membrane assembly 04. The backwash device allows for cleaning of membrane assembly 04, ensuring long-term and effective filtration by membrane assembly 04.

[0047] To further enhance the mixing of heavy metal wastewater and improve treatment effectiveness, an inward-rotating drainage plate is installed in GO pretreatment column 02. This allows the wastewater to remain in GO pretreatment column 02 longer as it circulates between GO pretreatment column 02 and inlet tank 01, allowing for more thorough mixing of wastewater and microorganisms. Furthermore, membrane assembly 04 is coaxially arranged within MBR reactor 03 and located in its center. This allows the wastewater to move along the surface of membrane assembly 04 during agitation, providing a rotational force that promotes biochemical reactions near the surface of module 04. This also reduces or delays clogging of the membrane assembly, increasing the effective filtration time of membrane assembly 04 and thereby improving production efficiency.

[0048] In order to further improve the treatment efficiency of heavy metal wastewater, the controller 08 is set to perform automatic control, and the entire treatment process is generally controlled and coordinated to ensure the efficient treatment of heavy metal wastewater.

[0049] The working parameters of each sub-equipment and facility in the reactor can be determined according to the actual situation. In this embodiment, the mesh size of the sieve in the water inlet pool 01 is 1mm, the GO pretreatment column 02 is a cylinder with a diameter of 40cm and a height of 100cm. The MBR reaction tank 03 is a rectangular container with an effective volume of 500L. The membrane component 04 adopts a polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membrane with a molecular weight cutoff of 100,000, a membrane pore size of 0.12μm, and an effective surface area of 13.9㎡. The aeration pipe 91 and the blower 92 provide an oxygen environment for the microorganisms in the MBR reaction tank 03, and the hydraulic retention time (HRT) is 6 to 7h. The pump start and stop time are set to 12min and 3min, and the membrane component 04 is externally compacted. The operating pressure under normal operation is 25KPa, and the maximum operating pressure is 60KPa. The total power of the entire system is 0.25KW, and the maximum daily water output is 25m 3 .

[0050] Reference Attachment Figure 2 This proposal provides a wastewater treatment method, which is applied to the graphene oxide-enhanced membrane bioreactor provided in this proposal. This method uses influent filtration to initially filter out large particles from heavy metal wastewater. This pretreatment mixing process then fully mixes and filters the wastewater with GO to form a biologically active mixed solution. Subsequently, under the MBR membrane reaction, filtration conditions are rationally adjusted to achieve efficient wastewater treatment results. The ability to adjust filtration conditions in real time as needed fully meets diverse wastewater treatment requirements.

[0051] The wastewater treatment method mainly comprises the following steps:

[0052] S1: Obtain a filtration start signal, form a first water inlet instruction, and send the first water inlet instruction to perform water inlet filtration processing.

[0053] This step primarily involves preliminary filtration of the raw water, removing large particles from the heavy metal wastewater to facilitate subsequent in-depth biochemical treatment of the heavy metal wastewater. Controller 08 receives a start signal and begins the filtration process. It first sends a first water inlet command, opening the inlet of water inlet tank 01. Raw water enters the inlet tank 01 after being filtered through a screen.

[0054] S2: Acquire a water level signal, form a first mixing instruction according to the water level signal, and perform pre-processing and mixing according to the first mixing instruction.

[0055] In this step, pretreatment mixing treatment is performed according to the first mixing instruction, including: starting the first water inlet pump 05 and the first return water pump 05 to circulate sewage, and adding adaptive microorganisms for mixing to form pretreated mixed sewage; collecting temperature data of the pretreated mixed sewage during the first pretreatment cycle, and controlling the temperature of the pretreated mixed sewage according to the temperature data; collecting sludge concentration data of the pretreated mixed sewage during the first pretreatment cycle to form first concentration data, and judging whether to form a deep mixing treatment instruction based on the first concentration data.

[0056] This step is mainly a mixing treatment method in GO pretreatment. By turning on the first water inlet pump 05 and the first return water pump 05, the GO pretreatment column 02 forms a circulating space connected with the water inlet pool 01, and the heavy metal wastewater is fully stirred so that it is fully and evenly mixed and preliminarily reacted with suitable biological substances. At the same time, since the GO pretreatment column 02 is composed of GO material, and GO has a partially amorphous structure, the edges and surface defects contain rich hydrophilic oxygen-containing functional groups, including hydroxyl, carboxyl and epoxy groups. These oxygen-containing functional groups can promote the adsorption between graphene oxide and heavy metals through π-π interactions, electrostatic effects, hydrogen bonds, hydrophobic interactions and other non-covalent interactions. Therefore, the heavy metal wastewater can undergo partial adsorption reactions during the circulation mixing process, and the wastewater can be further effectively treated.

[0057] Furthermore, to ensure microbial activity and adaptability during the circulation process, wastewater temperature is regularly monitored to ensure effective pretreatment. Furthermore, sludge concentration is used as a criterion for determining adequate mixing, enabling the determination of work points and the transition to advanced treatment. In this example, the sludge concentration threshold is set at 1.72 g / L, which can be adjusted as needed.

[0058] S3: Acquire first concentration data, generate a depth mixing processing instruction according to the first concentration data, stop the pre-processing mixing process according to the depth mixing processing instruction, and perform the depth mixing process.

[0059] According to the deep mixing processing instruction, the pretreatment mixing processing is stopped and the deep mixing processing is performed, including: turning off the first water inlet pump 05 and the first return water pump 05, and turning on the second water inlet pump 07, introducing the pretreated mixed sewage into the MBR reaction tank 03, and adding the first amount of powdered GO into the MBR reaction tank 03; collecting GO concentration data within the first deep treatment cycle to form second concentration data; obtaining the second concentration data, and performing the following judgment operation based on the second concentration data: when the second concentration data is less than the GO concentration threshold, adding the second amount of powdered GO; when the second concentration data is not less than the GO concentration threshold, stopping the addition of the second amount of powdered GO.

[0060] Deep treatment mainly includes the biochemical reaction treatment of GO powder, the biochemical reaction treatment of microorganisms and the filtration treatment of membrane assembly 04. As for the input amount of GO powder, it needs to be determined within a certain range when the pollutant content in heavy metal wastewater is relatively stable. In this embodiment, based on actual experimental conditions, the initial input amount of GO powder is different from the subsequent input amount. At the same time, whether to add powdered GO in the subsequent stage needs to be judged based on the concentration of GO in the wastewater. According to experiments, the first input amount is 400 mg / L and the second input amount is 150 mg / L. The better GO concentration in sewage is maintained between 100 mg / L and 500 mg / L, and a numerical value can be selected as the GO concentration threshold as needed.

[0061] S4: collecting deep treatment temperature data, deep treatment dissolved oxygen data and deep treatment pH data during the deep mixing treatment cycle, and adjusting the treatment effect according to the deep treatment temperature data, deep treatment dissolved oxygen data and deep treatment pH data.

[0062] Different treatment requirements and heavy metal wastewater contamination levels require adjustments to process parameters in the treatment process to ensure that the treatment of heavy metal wastewater is always at a high level of efficiency. In this embodiment, the wastewater treatment to be performed takes into account the activity of microorganisms, environmental conditions, and oxygen requirements for the reaction. The main consideration is monitoring and adjusting temperature, dissolved oxygen concentration, and pH value to achieve efficient treatment results.

[0063] Of course, after long-term experimental analysis, the most suitable process parameters for the GO-MBR reactor treatment process are a temperature of not less than 21°C during deep treatment, a dissolved oxygen solubility of not less than 4.0 mg / L, and a pH value between 6 and 9.

[0064] The following is a detailed description of the process parameters based on the data collected in the experiment. At the same time, during the experiment, the treatment effects of the conventional pretreatment column-MBR treatment method, the MBR treatment method and the traditional process were compared to determine the efficient treatment effect of the new membrane bioreactor:

[0065] The water quality content of heavy metal wastewater used in the experiment is as follows Figure 3 After the wastewater treatment method of this embodiment, COD, NH3-N, turbidity, Cd 2+ As well as the content of bacteria, SS and coliform bacteria.

[0066] refer to Figures 4 to 6 The effects of temperature and dissolved oxygen on COD removal and the comparison of COD removal rates among different processes were determined.

[0067] GO added to the bioreactor can be adsorbed and aggregated by microorganisms to form a GO-loaded microbial consortium. Biodegradation involves suspended microbial flocs and biofilms attached to the GO surface. A synergistic effect of microbial degradation and GO adsorption exists. Combined with the membrane's efficient physical separation, this ensures excellent effluent quality and can purify pollutants that are inaccessible to simple biochemical purification or GO adsorption. The MBR (Medium Bioremediation Reactor) decontamination mechanism involves simultaneous microbial reaction and membrane retention. Microorganisms react with pollutants, forming large aggregates that are separated and retained by the membrane, resulting in only the removal of larger molecular weight pollutants. Compared to conventional aeration treatment processes, the removal efficiency of the MBR process alone is superior, demonstrating the important role played by the microorganisms in the reactor and the ability of microorganisms to grow and reproduce under oligotrophic conditions. Although the MBR membrane's retention rate for small hydrophilic molecules is low, it significantly reduces membrane flux. Therefore, pretreatment is required to remove most organic matter when using MBR for wastewater purification. GO is more suitable for the pretreatment of MBR membranes because GO is a high-performance composite material composed of two porous, loose, and fiber-rich substances, with a larger specific surface area, toughness, and strong adsorption capacity; and graphene oxide has a partially amorphous structure, and its edges and surface defects contain rich hydrophilic oxygen-containing functional groups including hydroxyl, carboxyl, and epoxy groups. These oxygen-containing functional groups can promote the adsorption between graphene oxide and heavy metals through π-π interactions, electrostatic effects, hydrogen bonds, hydrophobic interactions, and other non-covalent interactions. In addition, there are pores of several microns between GO particles, which are equivalent to the transition pores of granular carbon. The flow of water through the pores increases the adsorption capacity of GO, thereby playing a mechanical interception role on large molecular organic matter. In addition, a retention layer and a concentration polarization layer are formed on the surface of GO and MBR, which also have a certain thickness and can play a multi-layer interception role.

[0068] refer to Figures 7 to 9The effects of temperature and dissolved oxygen on NH3-N removal and the comparison of NH3-N removal rates by different processes were determined.

[0069] As the system operation time increases, the layered porous structure of graphene oxide powder particles provides a breeding ground for the reaction between microorganisms and ammonia nitrogen, which can enhance the effect of microbial degradation and thus improve the removal effect of ammonia nitrogen by the entire system.

[0070] Figure 10 The figure shows the comparison of turbidity removal rates by different processes.

[0071] At the beginning of operation, since the gel layer on the membrane surface has not yet formed, the membrane has poor retention effect on small molecular colloidal substances, resulting in the membrane effluent turbidity changing greatly with the change of inlet turbidity. As the operation time increases, a gel layer is formed on the membrane surface, which makes the actual filtration pore size of the membrane smaller, enhances the membrane's retention effect on tiny colloidal substances, and thus increases the membrane effluent turbidity removal rate.

[0072] Figure 11 For different processes, Cd 2+ Comparison of removal rates.

[0073] The surface of the GO pretreatment column 02 contains a variety of negatively charged surface functional groups. These functional groups can form specific complexes with heavy metal ions in the wastewater through coordination, which can fix the heavy metal ions on the surface of the pretreatment column. At the same time, the negatively charged oxygen-containing functional groups introduced by the added GO powder particles at the edges and surface defects combine with the negatively charged biochar to serve as adsorption sites for complexation with heavy metal ions, greatly improving the removal efficiency of heavy metal ions.

[0074] Regarding the levels of bacteria, SS, and coliform bacteria, the raw water had a high chlorine content, resulting in a low total bacterial count. However, after dechlorination in the pretreatment column, the total bacterial count increased. This is because the surface of the pretreatment column provides a breeding ground for bacterial growth. The pore size of the MBR membrane used in this experiment is 0.12μm, while the smallest bacteria are approximately 0.2μm. After using the pretreatment column and adding GO to the MBR tank, the GO and other contaminants in the water were adsorbed to a diameter of over 0.4μm. Therefore, the MBR membrane achieved 100% bacterial removal. Suspended SS and coliform bacteria were not detected in the effluent, demonstrating that the MBR completely retained them.

[0075] S5: Obtain the membrane permeability value, and perform a cleaning operation according to the membrane permeability value.

[0076] This step specifically includes the following steps:

[0077] The membrane permeability value is collected during the first cleaning cycle, and the following cleaning judgment is made based on the membrane permeability value: when the membrane permeability value is greater than the membrane permeability threshold, the membrane permeability value collected during the first cleaning cycle is continued to be compared and judged; when the membrane permeability value is not greater than the membrane permeability threshold, the MBR reaction tank 03 is emptied and a backwash operation is performed, and after the operation, the membrane permeability value is obtained and compared with the membrane permeability threshold: if the membrane permeability value is greater than the membrane permeability threshold, the backwash operation is stopped; if the membrane permeability value is not greater than the membrane permeability threshold, the backwash operation is continued until the obtained membrane permeability value is greater than the membrane permeability threshold.

[0078] Among them, when the membrane permeability value is not greater than the membrane permeability threshold, the MBR reaction tank 03 is emptied and a backwashing operation is performed, including: closing the second water inlet pump 07 and emptying the MBR reaction tank 03; starting the first backwash pump 94 and the second backwash pump 95 for initial flushing; closing the first backwash pump 94 and the second backwash pump 95, and adding cleaning liquid to the MBR reaction tank 03 for soaking; emptying the cleaning liquid, and starting the first backwash pump 94 and the second backwash pump 95 for multiple final flushings.

[0079] Backwashing can be done with clean water, weak acid or weak alkali, but the cleaning effects are different. Figure 12 , is the membrane permeability under different conditions. It can be determined that the effect of using weak alkali cleaning is better.

[0080] In addition, backwashing can also be performed at regular intervals, so there is no need to consider real-time monitoring for control, which simplifies the cleaning process and reduces the cost of cleaning monitoring.

[0081] In summary, the embodiments provided by the present invention have the following main effective effects:

[0082] The graphene oxide-enhanced membrane bioreactor pre-treats wastewater by establishing a GO (graphene oxide) pre-treatment column. GO's high specific surface area, toughness, adsorption capacity, and the interaction between functional groups enable efficient adsorption of heavy metals in wastewater. Effective mixing and initial reaction between wastewater and treatment materials can be achieved during the pre-treatment stage, providing a material basis for subsequent deep treatment. At the same time, the biological filtration treatment of the MBR reaction tank can fully remove pollutants from wastewater. Furthermore, due to the fully and evenly mixed sewage, pollutants in the sewage can be efficiently intercepted and degraded, forming a highly efficient process system for treating heavy metal wastewater, achieving efficient treatment of heavy metal wastewater. Furthermore, because the treatment materials are easily accessible and long-lasting and stable, they can continuously and effectively purify wastewater, meeting production needs for heavy metal wastewater treatment.

[0083] The wastewater treatment method uses influent filtration to perform preliminary filtration of large particles in heavy metal wastewater. The subsequent pretreatment mixing treatment is to fully mix and filter the wastewater with GO to form a biological mixed liquid. Subsequently, the filtration conditions are reasonably adjusted under the MBR membrane reaction to achieve a wastewater treatment effect that meets the requirements of efficient treatment. Since the filtration conditions can be adjusted in real time according to needs, it can fully meet the different usage requirements of wastewater treatment. In addition, by monitoring the permeability of the filter membrane to control the backwash system to perform timely backwashing of the membrane component 04, it can effectively avoid the situation where the membrane component 04 is blocked and the filtration efficiency is reduced, ensuring that the entire graphene oxide enhanced membrane bioreactor can treat metal wastewater efficiently and long-term, fully meeting the needs of heavy metal wastewater treatment.

[0084] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A wastewater treatment method, characterized in that: A graphene oxide-enhanced membrane bioreactor is used, comprising a controller, an inlet tank, a GO pretreatment column, an MBR reaction tank, a membrane assembly, a first inlet pump, a first return pump, and a second inlet pump; the inlet end of the first inlet pump is connected to the inlet tank, and the outlet end of the first inlet pump is connected to the GO pretreatment column; the inlet end of the first return pump is connected to the GO pretreatment column, and the outlet end of the first return pump is connected to the inlet tank; the inlet end of the second inlet pump is connected to the GO pretreatment column, and the outlet end of the second inlet pump is connected to the MBR reaction tank; the membrane assembly is arranged in the MBR reaction tank; The controller is connected to the first water inlet pump, the second water inlet pump and the first water return pump respectively; Wastewater treatment methods include: Obtaining a filtration start signal, forming a first water inlet instruction, and sending the first water inlet instruction to perform water inlet filtration processing; Acquiring a water level signal, forming a first mixing instruction according to the water level signal, and performing pre-processing and mixing according to the first mixing instruction; Acquire first concentration data, form a depth mixing processing instruction according to the first concentration data, and stop pre-processing mixing processing according to the depth mixing processing instruction to perform depth mixing processing: The first water inlet pump and the first water return pump are turned off, and the second water inlet pump is turned on, the pretreated mixed sewage is introduced into the MBR reaction tank, and a first amount of powdered GO is added to the MBR reaction tank; GO concentration data is collected during the first deep treatment cycle to form second concentration data; the second concentration data is obtained, and the following judgment operation is performed based on the second concentration data: when the second concentration data is less than a GO concentration threshold, the second amount of powdered GO is added; when the second concentration data is not less than the GO concentration threshold, the addition of the second amount of powdered GO is stopped; Collecting deep treatment temperature data, deep treatment dissolved oxygen data, and deep treatment pH data during the deep mixing treatment cycle, and adjusting the treatment effect according to the deep treatment temperature data, the deep treatment dissolved oxygen data, and the deep treatment pH data; Obtain a membrane permeability value, and perform a cleaning operation according to the membrane permeability value.

2. The wastewater treatment method according to claim 1, wherein The graphene oxide enhanced membrane bioreactor also includes a temperature controller and a first agitator; the temperature controller is connected to the GO pretreatment column; the first agitator is arranged in the MBR reaction tank; and the controller is connected to the temperature controller and the first agitator respectively.

3. The wastewater treatment method according to claim 2, wherein The graphene oxide enhanced membrane bioreactor also includes a blower and an aeration pipe; one end of the aeration pipe is arranged in the MBR reaction tank and close to the membrane assembly, and the other end of the aeration pipe is connected to the blower; the controller is connected to the blower.

4. The wastewater treatment method according to claim 3, wherein: The graphene oxide enhanced membrane bioreactor also includes a first backwash pump and a second backwash pump; the water outlet of the first backwash pump is connected to the external filtration space of the membrane assembly, and the water inlet of the second backwash pump is connected to the internal filtration space of the membrane assembly.

5. The wastewater treatment method according to claim 4, wherein: The pre-processing mixing process according to the first mixing instruction includes: Turn on the first water inlet pump and the first water return pump to circulate the sewage, and add adaptive microorganisms to mix the sewage to form pretreated mixed sewage; collecting temperature data of the pretreated mixed sewage during a first pretreatment cycle, and performing temperature control on the pretreated mixed sewage according to the temperature data; The sludge concentration data of the pretreated mixed sewage is collected during the first pretreatment cycle to form the first concentration data, and it is determined whether the deep mixing treatment instruction is generated based on the first concentration data.

6. The wastewater treatment method according to claim 4, wherein: The obtaining of the membrane permeability value and performing the cleaning operation according to the membrane permeability value includes: During the first cleaning cycle, the membrane permeation value is collected, and the following cleaning judgments are made based on the membrane permeation value: When the membrane permeability value is greater than the membrane permeability threshold, continue to collect the membrane permeability value according to the first cleaning cycle for comparison and judgment; When the membrane permeability value is not greater than the membrane permeability threshold, the MBR reaction tank is drained and backwashing is performed. After the operation, the membrane permeability value is obtained and compared with the membrane permeability threshold: If the membrane permeability value is greater than the membrane permeability threshold, the backwashing operation is stopped. If the membrane permeability value is not greater than the membrane permeability threshold, the backwashing operation is continued until the obtained membrane permeability value is greater than the membrane permeability threshold.

7. The wastewater treatment method according to claim 6, wherein: When the membrane permeability value is not greater than the membrane permeability threshold, the MBR reaction tank is emptied and a backwash operation is performed, including: Turn off the second water inlet pump and drain the MBR reaction tank; Turning on the first backwash pump and the second backwash pump to perform an initial flush; Turn off the first backwash pump and the second backwash pump, and add cleaning liquid to the MBR reaction tank for soaking; The cleaning liquid is drained, and the first backwash pump and the second backwash pump are turned on to perform multiple final flushes.

Images