A device and method for synergistic treatment of algae and nutrients

Abstract

This invention discloses a device and method for synergistic treatment of algae and nutrients, belonging to the technical field of synergistic treatment of algae and nutrients. The key technical points are: it includes an algae pretreatment chamber, a nutrient enhancement removal chamber, and an algae degradation chamber, with a membrane separating the pretreatment chamber and the degradation chamber, and a membrane separating the enhancement removal chamber and the degradation chamber. This invention has a synergistic effect of highly efficient algae removal, enhanced nutrient treatment, and energy recovery. The operation process is green and low-carbon, and it is suitable for the comprehensive treatment of algal blooms in lakes, reservoirs, and other water bodies.

Description

Technical Field

[0001] This invention relates to the field of algae removal and synergistic management of nutrients, and more specifically, to an apparatus and method for algae removal and synergistic management of nutrients. Background Technology

[0002] Eutrophication is one of the major water pollution problems worldwide. Its core issue is the excessive proliferation of algae due to excessive nitrogen and phosphorus in water, leading to algal blooms. Algal blooms not only disrupt the ecological balance of aquatic bodies but can also cause a rapid decline in dissolved oxygen, large-scale mortality of aquatic organisms, and, in some cases, the release of algal toxins, seriously threatening the ecological environment and human health. More importantly, after algae die, the organic matter and nutrients released by the ruptured cells further exacerbate eutrophication, potentially leading to repeated algal blooms and a vicious cycle. Therefore, effectively removing algae and simultaneously treating the nutrients they release has become a key technical challenge in solving eutrophication.

[0003] Currently, algae control technologies mainly fall into three categories: chemical, physical, and biological methods. Chemical methods rapidly kill algae by adding agents such as copper sulfate and hydrogen peroxide. While effective quickly, these methods are prone to causing secondary pollution and pose high costs and safety risks. Physical methods, such as filtration, shading, and ultrasonic technology, are suitable for small-scale treatment but are energy-intensive and require expensive equipment, making them difficult to implement in large-scale water bodies. Biological methods, by introducing filter-feeding organisms or functional microorganisms, are relatively environmentally friendly and have long-lasting effects, but they have long reaction times and are highly dependent on environmental conditions, making them unsuitable for emergency treatment needs. Despite their respective advantages, these technologies share a common drawback: they cannot simultaneously address the problem of algae removal and the management of nutrients released after algae die-off. Nitrogen, phosphorus, and other nutrients released after algae die-off re-enter the water cycle, becoming a breeding ground for the next algal bloom. Furthermore, existing technologies have low energy efficiency and typically fail to integrate algae control with energy recovery, resulting in high operating costs.

[0004] Microbial fuel cells (MFCs), as an emerging technology for pollutant treatment and energy recovery, have attracted much attention in the field of water treatment in recent years. MFCs utilize electroactive microorganisms to degrade organic pollutants in water and generate electricity, offering advantages such as being environmentally friendly, highly efficient, and low-cost. However, current research on MFCs is mostly focused on wastewater treatment, and its application in the simultaneous treatment of algae and nutrients is still immature, especially in achieving the synergistic effect of algae removal, nutrient treatment, and energy recovery. Therefore, the inventors propose a device and method for the synergistic treatment of algae and nutrients. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for the synergistic treatment of algae removal and nutrient elements, with algae removal, nutrient element removal and energy recovery as the core objectives, forming a green, efficient and low-carbon comprehensive treatment method, and ultimately achieving comprehensive treatment of algal bloom water bodies.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] The first aspect of the present invention provides an apparatus and method for algae removal and synergistic treatment of nutrients, comprising an algae solution pretreatment chamber, a nutrient element enhanced removal chamber, and an algae degradation chamber, wherein a diaphragm is provided between the algae solution pretreatment chamber and the algae degradation chamber, and a diaphragm is provided between the nutrient element enhanced removal chamber and the algae degradation chamber.

[0008] In conjunction with the first aspect, the present invention is further configured to include: a wire, a first resistor and a second resistor; the algae pretreatment chamber, the algae degradation chamber and the nutrient element enhanced removal chamber are respectively provided with a first cathode electrode, an anode electrode and a second cathode electrode; the wire connects the first cathode electrode, the first resistor and the anode electrode in series to form a first current loop; and the wire connects the second cathode electrode, the second resistor and the anode electrode in series to form a second current loop.

[0009] The first cathode electrode in the algae pretreatment chamber is an electrode that facilitates the electrochemical reduction of oxygen to generate hydrogen peroxide, such as carbon felt, carbon rod, carbon granules, or carbon cloth. The anode electrode in the algae degradation chamber and the second cathode electrode in the nutrient element enhanced removal chamber are electrodes that facilitate microbial attachment, such as carbon felt, carbon brush, carbon granules, or carbon cloth. The conductors are copper wire, aluminum wire, or titanium wire.

[0010] In conjunction with the first aspect, the present invention is further configured such that the diaphragm is a cation exchange membrane, an anion exchange membrane, or a bipolar membrane.

[0011] In conjunction with the first aspect, the present invention is further configured such that: a first air inlet is provided at the end of the algae pretreatment chamber away from the algae degradation chamber, a first water outlet is provided at the top of the algae pretreatment chamber, and a first water inlet is also provided on the side of the algae pretreatment chamber.

[0012] In conjunction with the first aspect, the present invention is further configured such that: the top of the algae degradation chamber is provided with a second water outlet, and the side of the algae liquid pretreatment chamber is provided with a second water inlet.

[0013] In conjunction with the first aspect, the present invention is further configured such that: a second air inlet is provided at the end of the nutrient element enhancement removal chamber away from the algae degradation chamber, a third water outlet is provided at the top of the algae liquid pretreatment chamber, and a third water inlet is provided on the side of the algae liquid pretreatment chamber.

[0014] In conjunction with the first aspect, the present invention is further configured such that: a second air inlet is provided at the end of the nutrient element enhanced removal chamber away from the algae degradation chamber, a third water outlet is provided at the top of the nutrient element enhanced removal chamber, and a third water inlet is provided on the side of the nutrient element enhanced removal chamber.

[0015] In conjunction with the first aspect, the present invention is further configured as follows: the first catholyte is river water, lake water, reservoir water, or pond water containing algae; the inoculum for the electroactive microorganisms and nutrient-enhanced removal microorganisms is sludge from the oxidation ditch of an oxidation ditch wastewater treatment plant; the anolyte composition is: 1 g / L sodium acetate; 0.1 g / L Microcystis aeruginosa algal powder; 0.15 g / L potassium sulfate; 50 mM HEPES buffer (pH = 7.4); trace elements 1 mL / L; the trace element composition in the algae degradation chamber is: MgSO4: 3.0 g / L; MnSO4·H2O: 0.5 g / L; NaCl: 1.0 g / L; FeSO4·7H2O: 0.1 g / L; CaCl2·2H2O: 0.1 g / L; CoCl2·6H2O: 0.1 g / L; ZnC The first catholy solution is: L2: 0.13 g / L; CuSO4·5H2O: 0.01 g / L; KAl(SO4)2·12H2O: 0.01 g / L; H3BO3: 0.01 g / L; Na2MoO4: 0.025 g / L; NiCl2·6H2O: 0.024 g / L; Na2WO4·2H2O: 0.024 g / L; The second catholy solution is: NaHCO3: 1 g / L; NH4Cl: 0.18 g / L; 50 mM HEPES buffer (pH = 7.4); Trace elements 12.5 mL / L; The trace element composition in the nutrient element enhanced removal chamber is the same as that in the algae degradation chamber.

[0016] A second aspect of the present invention also provides a method for the synergistic treatment of algae removal and nutrient elements, comprising the following steps:

[0017] S1. Start-up device. First catholyte is added to the algae pretreatment chamber, while air or oxygen is simultaneously introduced into the algae pretreatment chamber via a peristaltic pump through the first air inlet at a flow rate of 1-100 mL / min; anolyte is added to the algae degradation chamber to inoculate sludge from the oxidation ditch of the wastewater treatment plant; second catholyte is added to the nutrient enhancement removal chamber to inoculate sludge from the oxidation ditch of the wastewater treatment plant, while air is intermittently introduced into the nutrient enhancement removal chamber via a peristaltic pump through the second air inlet at a flow rate of 1-100 mL / min.

[0018] S2. Acclimation of electroactive microorganisms and nutrient element enhanced removal microorganisms: Under closed-loop conditions, the above three chambers are acclimated and operated at room temperature of 24℃-28℃; the replacement cycle of the first catholyte, anolyte and second catholyte is 2-4 days. When the output voltage of the first current loop and the second current loop is stable at similar values ​​for at least 3 consecutive cycles, it indicates that the acclimation and start-up of electroactive microorganisms in the algae degradation chamber and nutrient element enhanced removal microorganisms in the nutrient element enhanced removal chamber are successful.

[0019] S3. Operating the device, the first cathode liquid in step S1 is replaced with 2.0 × 10 9 Using Microcystis aeruginosa at a concentration of 1 / L and a NaCl solution of 0.066 g / L, after 2-4 days of operation, the anolyte is replaced with the treated first catholyte, and the replaced first catholyte is replenished. After the device continues to operate for another 2-4 days, the second catholyte is replaced with the treated anolyte, 1 g / L NaHCO3, and 12.5 mL / L trace elements. At the same time, the treated first catholyte is injected into the algae degradation chamber, and the replaced first catholyte is replenished. This operation is repeated continuously with an operating cycle of 2-4 days.

[0020] In conjunction with the second aspect, the present invention is further configured such that: the air or oxygen in the first air inlet is continuously supplied with an intake rate of 40-80 mL / min; the air or oxygen in the second air inlet is intermittently supplied with an intake rate of 40-80 mL / min, an intake time of 0.1-7200 min, and a stop intake time of 0.1-7200 min.

[0021] In summary, the present invention has the following beneficial effects:

[0022] (1) Synergistic effect of three chambers for efficient algae removal: the algae pretreatment chamber generates hydrogen peroxide in situ to quickly inactivate algae; the algae degradation chamber extracts chemical energy from the organic matter of dead algae to achieve energy self-sufficiency; the nutrient element enhanced removal chamber enhances nitrogen and phosphorus removal. The three chambers have clear division of labor and are highly efficient in synergy.

[0023] (2) Green and low-carbon operation with energy recovery: It utilizes electroactive microorganisms to metabolize algal organic matter to provide electricity, supports the electrochemical generation of hydrogen peroxide, and realizes energy recovery. No additional carbon source or external power is required, and the operation is low-energy and environmentally friendly.

[0024] (3) Enhance nitrogen and phosphorus removal and prevent secondary pollution: The nitrogen and phosphorus nutrients in the water are further removed through the nutrient element enhancement removal chamber, which inhibits the secondary pollution caused by the release of nutrients after the algae die, and ensures the long-term stability of the treatment effect.

[0025] (4) Modular design and wide applicability: The device adopts a modular structure design, and the operating parameters can be adjusted according to the degree of pollution and the scale of treatment. It can be flexibly applied to the treatment of different types of eutrophic water bodies (such as lakes and reservoirs), and has significant application potential and economic value, especially in the field and remote areas. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a three-chamber MFCs device;

[0027] Figure 2 This describes the change in hydrogen peroxide production over time in the algae pretreatment chamber of Example 1.

[0028] Figure 3 This is the change in the maximum photodynamic efficiency (Fv / Fm) of algae in the algae pretreatment chamber of Example 1 over time;

[0029] Figure 4 The changes in ammonia nitrogen and total nitrogen concentrations over time in the algae pretreatment chamber of Example 1;

[0030] Figure 5 This describes the change in total phosphorus concentration over time in the algae pretreatment chamber of Example 1.

[0031] Figure 6 The changes in ammonia nitrogen and total nitrogen concentrations over time in the algae degradation chamber of Example 1;

[0032] Figure 7 This describes the change in total phosphorus concentration over time in the algae degradation chamber of Example 1.

[0033] Figure 8 This is the change in ammonia nitrogen and total nitrogen concentrations over time in the nutrient element fortification and removal chamber of Example 1;

[0034] Figure 9 This is the change in total phosphorus concentration over time in the nutrient fortification and removal chamber of Example 1;

[0035] Figure 10 This is the output power density of the three-chamber MFCs in Example 1.

[0036] In the diagram: 1 Algal solution pretreatment chamber; 2 First water inlet; 3 First cathode electrode; 4 First air inlet; 5 Wire; 6 First water outlet; 7 First resistor; 8 Second resistor; 9 Second water outlet; 10 Third water outlet; 11 Second air inlet; 12 Third water inlet; 13 Second cathode electrode; 14 Nutrient element enhanced removal chamber; 15 Diaphragm; 16 Second water inlet; 17 Anode electrode; 18 Algal degradation chamber. Detailed Implementation

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] Example 1:

[0039] Step 1: Construct a three-chamber MFCs device, such as Figure 1 As shown. The algae pretreatment chamber 1, algae degradation chamber 18 and nutrient element enhanced removal chamber 14 are all made of plexiglass. The three reaction chambers are identical in size, with a cubic structure on the outside and a cylindrical cavity on the inside. Each chamber has a volume of 50 mL and is separated by a cation exchange membrane (CM I-7000) 15.

[0040] The first water inlet 2, the first air inlet 4, and the first water outlet 6 of the algae pretreatment chamber, the second water inlet 16 and the second water outlet 9 of the algae degradation chamber, and the third water inlet 12, the second air inlet 11, and the third water outlet 10 of the nutrient element enhancement removal chamber are all straight-through quick-connect air pipes with an inner diameter of 4mm.

[0041] Step Two: Setting up the Electrodes and Current Circuit. The first cathode electrode 3 (carbon rod and carbon felt), the anode electrode 17 (carbon rod and carbon felt), and the second cathode electrode 13 (carbon rod and carbon felt) are placed in the algae pretreatment chamber 1, the algae degradation chamber 18, and the nutrient element enhanced removal chamber 14, respectively. The apparent dimensions of the carbon rod (Beijing Sanye Carbon Materials Co., Ltd.) are... The carbon felt (Beijing Sanye Carbon Materials Co., Ltd.) has an apparent size of 3.0cm × 1.5cm × 1.0cm. A first current loop is formed by connecting the first cathode electrode 3, the first resistor 7, and the anode electrode 17 in series using wire 5 (copper wire). A second current loop is also formed by connecting the second cathode electrode 13, the second resistor 8, and the anode electrode 17 in series. During the device startup phase, both the first resistor 7 and the second resistor 8 are set to 1000Ω; during the device operation phase, both the first resistor 7 and the second resistor 8 are set to 50Ω.

[0042] Step 3: Start the device. Add 40 mL of the first cathodic solution to the algae pretreatment chamber 1. The solution has the composition of NaCl: 0.066 g / L. At the same time, use a peristaltic pump to introduce air into the algae pretreatment chamber 1 through the first air inlet 4 at a flow rate of 60 mL / min. Add 30 mL of anolyte to algae degradation chamber 18. The anolyte composition is: 1 g / L sodium acetate; 0.1 g / L *Microcystis aeruginosa* powder; 0.15 g / L potassium sulfate; 50 mM HEPES buffer (pH = 7.4); and 1 mL / L trace elements (composed of: MgSO4: 3.0 g / L; MnSO4·H2O: 0.5 g / L; NaCl: 1.0 g / L; FeSO4·7H2O: 0.1 g / L; CaCl2·2H2O: 0.1 g / L; CoCl2·6H2O: 0.1 g / L; ZnCl2: 0.13 g / L; CuSO4·5H2O: 0.01 g / L; KAl(SO4)2·12H2O: 0.01 g / L; H3BO3: 0.01 g / L; Na2MoO4: 0.025 g / L; N... 10g of sludge from the oxidation ditch of the Chaoyang Wastewater Treatment Plant in Nanchang City was inoculated with a solution of iCl2·6H2O: 0.024g / L; Na2WO4·2H2O: 0.024g / L. 30mL of a second cathodic solution with the following composition was added to the nutrient element enhanced removal chamber 14: NaHCO3: 1g / L; NH4Cl: 0.18g / L; 50mM HEPES buffer (pH = 7.4); and trace elements 12.5mL / L (same composition as above). 10g of sludge from the oxidation ditch of the Chaoyang Wastewater Treatment Plant in Nanchang City was inoculated with this solution. Simultaneously, air was intermittently introduced into the nutrient element enhanced removal chamber 11 through the second air inlet 11 at a flow rate of 60mL / min using a peristaltic pump. The intermittent aeration cycle was 6 hours, with continuous aeration for 3 hours followed by a 3-hour pause.

[0043] Step 4: Acclimation of Electroactive Microorganisms and Nutrient Enhancement Removal Microorganisms. Under closed-loop conditions, the three-chamber MFCs device was acclimated and operated at room temperature (26±2℃). The replacement cycle for the first catholyte, anolyte, and second catholyte was 3 days. When the output voltages of the first and second current loops stabilized at similar values ​​for at least three consecutive cycles, it indicated that the acclimation and startup of the electroactive microorganisms in algae degradation chamber 18 and the nutrient enhancement removal microorganisms in nutrient enhancement removal chamber 14 were successful.

[0044] Step 5: Run the apparatus. Replace the first catholyte in Step 3 with 40 mL of 2.0 × 10⁻⁶ solution. 9The algae were treated with 0.066 g / L Microcystis aeruginosa and 0.066 g / L NaCl. After 2 days of operation, the anolyte was replaced with the treated first catholyte, and the replaced first catholyte was replenished. After another 2 days of operation, the second catholyte was replaced with the treated anolyte mixed with 1 g / L NaHCO3 and 12.5 mL / L trace elements (composition as above), and the treated first catholyte was injected into algae degradation chamber 18, and the replaced first catholyte was replenished. This operation was repeated every 2 days. After 5 cycles of operation, samples were taken periodically to analyze the hydrogen peroxide concentration, algal maximum photon efficiency (Fv / Fm), ammonia nitrogen concentration, total nitrogen concentration, and total phosphorus concentration in algae pretreatment chamber 1; the ammonia nitrogen concentration, total nitrogen concentration, and total phosphorus concentration in algae degradation chamber 18; and the ammonia nitrogen concentration, total nitrogen concentration, and total phosphorus concentration in nutrient element enhanced removal chamber 14.

[0045] Step Six: Characterize the power generation performance of the device. During the 10th cycle of device operation, the output power of the MFCs composed of anode-first cathode and MFCs composed of anode-second cathode was characterized using the linear sweep voltammetry method.

[0046] Compare with Example 1:

[0047] The three-chamber MFCs device in this comparative example operates under open-circuit conditions, that is, the first current loop between the anode electrode 17 and the first cathode electrode 3 in step five of Example 1 is disconnected and not connected; at the same time, the second current loop between the anode electrode 17 and the second cathode electrode 13 is disconnected and not connected. All other operating conditions are consistent with those in Example 1.

[0048] Results: During one cycle of operation of the three-chamber MFCs device, the hydrogen peroxide concentration in the algae pretreatment chamber rapidly increased to 3.14 ± 0.16 mg / L, then gradually decreased and stabilized at around 2.70 mg / L; however, no hydrogen peroxide generation was observed under open-circuit conditions. Figure 2 This indicates that the three-chamber MFCs device can electrochemically generate hydrogen peroxide by extracting energy from algal biomass through electroactive microorganisms. The maximum photonic efficiency (Fv / Fm) of the algae gradually decreased from an initial 0.33 ± 0.01 to 0, while under open-circuit conditions, the maximum photonic efficiency (Fv / Fm) of the algae did not change significantly. Figure 3 This indicates that the algae were rapidly inactivated by the electrochemical generation of hydrogen peroxide. Simultaneously, the concentrations of ammonia nitrogen and total nitrogen in the algae pretreatment chamber gradually increased, reaching 4.94±0.62 mg / L and 41.18±1.06 mg / L, respectively, at 48 h, significantly higher than the 3.35±0.19 mg / L and 7.63±0.25 mg / L under open-circuit conditions. Figure 4The total phosphorus concentration gradually increased to 6.56±0.50 mg / L after 48 hours, which was also significantly higher than the 0.95±0.23 mg / L under open-circuit conditions. Figure 5 These results indicate that electrochemically generated hydrogen peroxide can promote the release of nitrogen and phosphorus nutrients from algae.

[0049] In the algae degradation chamber, the ammonia nitrogen concentration decreased from 4.94±0.10 mg / L to 1.57±0.10 mg / L (removal rate: 68.1%). Figure 6 The total nitrogen concentration decreased from 40.53±0.74 mg / L to 12.22±1.61 mg / L (removal rate: 69.9%). Figure 6 The total phosphorus concentration decreased from 6.55±0.13 mg / L to 5.43±0.13 mg / L (removal rate: 17.1%). Figure 7 These results indicate that the algal degradation chamber has a certain ability to remove nitrogen and phosphorus nutrients, and its ability to remove nitrogen is significantly better than that of phosphorus.

[0050] In the nutrient element enhanced removal chamber, the ammonia nitrogen concentration decreased from 1.57±0.10 mg / L to 0.01±0.02 mg / L (removal rate: 99.4%). Figure 8 The total nitrogen concentration decreased from 12.22±0.65 mg / L to 3.91±0.31 mg / L (removal rate: 67.9%). Figure 8 The total phosphorus concentration decreased from 5.43±0.12 mg / L to 0.26±0.06 mg / L (removal rate: 95.2%). Figure 9 These results demonstrate that the nutrient fortification removal chamber has an extremely high removal capacity for both nitrogen and phosphorus.

[0051] Furthermore, the maximum output power of MFCs consisting of an anode and a first cathode, and MFCs consisting of an anode and a second cathode, are 28.5 mW / m², respectively. 2 and 23.6mW / m 2 ( Figure 10 Meanwhile, under closed-loop conditions, the concentrations of ammonia nitrogen, total nitrogen, and total phosphorus in the effluent from both the algae degradation chamber and the nutrient enhancement removal chamber were lower than those under open-loop conditions. Figures 6-9 ).

[0052] The above results demonstrate that the three-chamber MFCs device can effectively recover chemical energy from algae and promote the removal of nitrogen and phosphorus nutrients.

[0053] Working principle:

[0054] This invention comprises three reaction units: an algae pretreatment chamber, an algae degradation chamber, and a nutrient element enhanced removal chamber. The algae pretreatment chamber serves as the chemical cathode of the MFCs, where oxygen is reduced to hydrogen peroxide via electrochemical methods, achieving rapid inactivation and pretreatment of algae. The algae degradation chamber acts as the bioanode of the MFCs, utilizing electroactive microorganisms to further metabolize the algal organic matter produced in the pretreatment chamber, converting its chemical energy into electrical energy to power the hydrogen peroxide generation at the chemical cathode, while simultaneously partially removing nitrogen and phosphorus nutrients from the water. The nutrient element enhanced removal chamber, also a biocathode, further enhances the removal of nitrogen and phosphorus from the effluent of the algae degradation chamber by controlling the oxygen concentration, thus preventing secondary pollution.

[0055] During operation, the first catholyte enters the algae pretreatment chamber, where the algae are inactivated and pretreated by electrochemically generated hydrogen peroxide, releasing nutrients such as nitrogen and phosphorus, and forming an algae pretreatment solution. Then, the algae pretreatment solution enters the algae degradation chamber, where electroactive microorganisms catalytically decompose the algal organic matter and generate electricity. This electricity is used to electrochemically generate hydrogen peroxide in the algae pretreatment chamber, while some nitrogen and phosphorus are removed by the microorganisms. Finally, the effluent from the algae degradation chamber enters the nutrient element enhanced removal chamber, where 1 g / L NaHCO3 and 12.5 mL / L trace elements (composition as above) are added. Nitrogen is enhancedly removed through nitrification and denitrification under intermittent air or oxygen conditions; phosphorus is enhancedly removed through microbial assimilation and struvite precipitation by the microorganisms and magnesium ions in the trace elements.

[0056] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for the synergistic treatment of algae and nutrients, characterized in that: It includes an algae pretreatment chamber, a nutrient element enhanced removal chamber, and an algae degradation chamber, with a diaphragm between the algae pretreatment chamber and the algae degradation chamber; It also includes wires, a first resistor and a second resistor. The algae pretreatment chamber, the algae degradation chamber and the nutrient element enhanced removal chamber are respectively provided with a first cathode electrode, an anode electrode and a second cathode electrode. The wires connect the first cathode electrode, the first resistor and the anode electrode in series to form a first current loop. The wires connect the second cathode electrode, the second resistor and the anode electrode in series to form a second current loop. The first catholy solution enters the algae pretreatment chamber to form an algae pretreatment solution. The algae pretreatment solution then enters the algae degradation chamber. The effluent from the algae degradation chamber enters the nutrient element enhanced removal chamber, where nitrogen is enhancedly removed through nitrification and denitrification processes under intermittent air or oxygen conditions. The first cathodic solution is river water, lake water, reservoir water, or pond water containing algae.

2. The algae removal and nutrient element synergistic treatment device according to claim 1, characterized in that: The diaphragm is a cation exchange membrane, an anion exchange membrane, or a bipolar membrane.

3. The algae removal and nutrient element synergistic treatment device according to claim 1, characterized in that: The algae pretreatment chamber is provided with a first air inlet at the end away from the algae degradation chamber, a first water outlet at the top of the algae pretreatment chamber, and a first water inlet on the side of the algae pretreatment chamber.

4. The algae removal and nutrient element synergistic treatment device according to claim 1, characterized in that: The top of the algae degradation chamber is provided with a second water outlet, and the side of the algae degradation chamber is provided with a second water inlet.

5. The algae removal and nutrient element synergistic treatment device according to claim 1, characterized in that: The nutrient element enhancement and removal chamber is provided with a second air inlet at the end away from the algae degradation chamber, a third water outlet at the top of the nutrient element enhancement and removal chamber, and a third water inlet on the side of the nutrient element enhancement and removal chamber.

6. The algae removal and nutrient element synergistic treatment device according to claim 1, characterized in that: The algae pretreatment chamber is filled with a first cathodic solution, the algae degradation chamber is filled with electroactive microorganisms and an anodic solution, and the nutrient element enhanced removal chamber is filled with nutrient element enhanced removal microorganisms and a second cathodic solution.

7. The algae removal and nutrient element synergistic treatment device according to claim 6, characterized in that: The first catholyte is river water, lake water, reservoir water, or pond water containing algae; the inoculum for the electroactive microorganisms and nutrient-enhanced removal microorganisms is sludge from the oxidation ditch of an oxidation ditch wastewater treatment plant; the anolyte composition is: 1 g / L sodium acetate; 0.1 g / L Microcystis aeruginosa powder; 0.15 g / L potassium sulfate; 50 mM HEPES buffer (pH=7.4); trace elements 1 mL / L; the trace element composition in the algae degradation chamber is: MgSO4: 3.0 g / L; MnSO4·H2O: 0.5 g / L; NaCl: 1.0 g / L; FeSO4·7H2O: 0.1 g / L; CaCl2·2H2O: 0.1 g / L; CoCl2·6H2O: 0.1 g / L; ZnCl2: 0.13 g / L; CuSO4·5H2O: 0.01 g / L. The following concentrations were used: KAl(SO4)2·12H2O: 0.01 g / L; H3BO3: 0.01 g / L; Na2MoO4: 0.025 g / L; NiCl2·6H2O: 0.024 g / L; Na2WO4·2H2O: 0.024 g / L; The second catholyte consisted of: NaHCO3: 1 g / L; NH4Cl: 0.18 g / L; 50 mM HEPES buffer (pH=7.4); and trace elements 12.5 mL / L. The trace element composition in the nutrient element enhanced removal chamber was the same as that in the algae degradation chamber.

8. A method for synergistic treatment of algae removal and nutrient elements, using the device for synergistic treatment of algae removal and nutrient elements as described in any one of claims 1-7, characterized in that: Includes the following steps: S1. Start-up device. Add the first cathodic liquid to the algae pretreatment chamber, and simultaneously use a peristaltic pump to introduce air or oxygen into the algae pretreatment chamber through the first air inlet at a flow rate of 1-100 mL / min; add anodic liquid to the algae degradation chamber and inoculate the sludge in the oxidation ditch of the oxidation ditch wastewater treatment plant; add the second cathodic liquid to the nutrient element enhanced removal chamber and inoculate the sludge in the oxidation ditch of the oxidation ditch wastewater treatment plant, and simultaneously use a peristaltic pump to intermittently introduce air into the nutrient element enhanced removal chamber through the second air inlet at a flow rate of 1-100 mL / min. S2. Acclimation of electroactive microorganisms and nutrient element enhanced removal microorganisms: Under closed-loop conditions, the above three chambers are acclimated and operated at room temperature of 24℃-28℃; the replacement cycle of the first catholyte, anolyte, and second catholyte is 2-4 days. When the output voltage of the first current loop and the second current loop stabilizes at similar values ​​for at least 3 consecutive cycles, it indicates that the acclimation and start-up of electroactive microorganisms in the algae degradation chamber and nutrient element enhanced removal microorganisms in the nutrient element enhanced removal chamber are successful. S3. Operating the device, the first cathode liquid in step S1 is replaced with 2.0 × 10 9 The device is prepared with Microcystis aeruginosa at a concentration of 1 / L and NaCl solution at a concentration of 0.066 g / L. After 2-4 days of operation, the anolyte is replaced with the treated first catholyte, and the replaced first catholyte is replenished. After another 2-4 days of operation, the second catholyte is replaced with the treated anolyte, 1 g / L NaHCO3, and 12.5 mL / L trace elements. At the same time, the treated first catholyte is injected into the algae degradation chamber, and the replaced first catholyte is replenished. This process is repeated continuously with a 2-4 day operating cycle.

9. The method for synergistic treatment of algae removal and nutrient elements according to claim 8, characterized in that: The air or oxygen in the first air inlet is continuously supplied at an intake rate of 40-80 mL / min; the air or oxygen in the second air inlet is intermittently supplied at an intake rate of 40-80 mL / min, with an intake time of 0.1-7200 min and a stop intake time of 0.1-7200 min.

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