Microbial battery wastewater treatment system and method for simultaneous nitrogen and phosphorus removal

Abstract

The present invention discloses a synchronous denitrification and dephosphorization microbial battery sewage treatment system and method, the system comprises a double-chamber microbial battery, a single-chamber microbial battery, a first crystallization tank and a second crystallization tank; the double-chamber microbial battery comprises a double-chamber battery chamber, a double-chamber battery resistor, a double-chamber battery anode, a double-chamber battery cathode and a double-chamber battery cation exchange membrane, the single-chamber microbial battery comprises a single-chamber battery chamber, a single-chamber battery resistor, a single-chamber battery anode and a single-chamber battery cathode; the second crystallization tank, the double-chamber battery chamber and the single-chamber battery chamber are all connected to the first crystallization tank. The system can be used for low C / N sewage treatment, can remove ammonia nitrogen and phosphorus at the same time, does not need to carry out additional nitrification and denitrification processes, aeration and aeration oxygen supply and other links, the treatment process can simultaneously obtain high-purity magnesium ammonium phosphate, diammonium hydrogen phosphate and diammonium dihydrogen phosphate and other products that can be directly used as fertilizers, and has the characteristics of good sewage treatment effect and high recycling efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment system and method using a microbial cell for simultaneous nitrogen and phosphorus removal. Background Art

[0002] Phosphorus is an essential chemical element for life activities and an important raw material for high-tech industries such as automobiles, medicine, and information technology. 90% of phosphorus obtained from mineral mining is used in agricultural production. Without phosphorus, agricultural production cannot achieve a good harvest.

[0003] The available phosphorus resources on the earth are becoming less and less. Data show that the price of phosphate rock has started to rise from 280 yuan / ton at the end of 2018. On January 20, 2019, in less than a month, the price of high-grade phosphate rock has risen by nearly 50%, especially the price of 30% grade phosphate rock is nearly 450 yuan / ton, close to the historical high. In 2022, the price of 30% grade phosphate rock will exceed 600 yuan / ton.

[0004] In some countries, due to the lack of phosphorus mineral resources, industry, academia and research have focused on strategic research on phosphorus recycling and utilization, building a phosphorus recycling and utilization industry chain, especially exploring how to recycle phosphorus from domestic renewable resources such as sewage. At present, renewable resource sewage contains a large amount of phosphorus, most of which is in the form of orthophosphate (PO4 3- ), and sewage treatment technology has also expanded from simple nitrogen and phosphorus removal to the recovery and reuse of phosphorus resources based on efficient phosphorus removal. Crystallization phosphorus removal is a method of efficiently recovering phosphorus from sewage. The amount of sludge produced by the crystallization method for recycling phosphorus is much smaller than that of biological and chemical precipitation methods, and the recovered phosphorus crystals are of high purity. Through simple processing, phosphorus crystals can be converted into fertilizers, feed additives and raw materials for the production of phosphate rock, which has certain economic benefits.

[0005] At the same time, microbial battery technology can effectively recycle and reuse organic energy stored in the form of COD in sewage. Therefore, it is necessary to develop a sewage treatment process equipment and supporting processes using microbial battery technology to recycle the organic energy in sewage into electrical energy, promote the crystallization of phosphorus in sewage and efficiently recycle and reuse it. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a simultaneous denitrification and phosphorus removal microbial cell sewage treatment system and method in view of the deficiencies of the above-mentioned prior art. The system uses a double-chamber microbial cell, a single-chamber microbial cell, a first crystallization tank and a second crystallization tank for low C / N sewage treatment, and can remove ammonia nitrogen and phosphorus at the same time without the need for additional nitrification and denitrification processes, aeration and aeration oxygen supply and other links. The treatment process can simultaneously obtain high-purity magnesium ammonium phosphate, diammonium hydrogen phosphate and diammonium dihydrogen phosphate and other products that can be directly used as fertilizers, and has the characteristics of good sewage treatment effect and high recycling efficiency.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a synchronous denitrification and dephosphorization microbial battery sewage treatment system, characterized in that it includes a double-chamber microbial battery, a single-chamber microbial battery, a first crystallization tank and a second crystallization tank;

[0008] The dual-chamber microbial battery comprises a dual-chamber battery chamber and a dual-chamber battery resistor, wherein a dual-chamber battery anode, a dual-chamber battery cathode and a dual-chamber battery cation exchange membrane are arranged in the dual-chamber battery chamber, and the dual-chamber battery cation exchange membrane is arranged between the dual-chamber battery anode and the dual-chamber battery cathode;

[0009] The dual-chamber battery chamber is provided with a dual-chamber battery inlet, a dual-chamber battery first outlet and a dual-chamber battery second outlet, wherein the dual-chamber battery inlet is located below the anode for the dual-chamber battery, the dual-chamber battery first outlet is located above the anode for the dual-chamber battery, and the dual-chamber battery second outlet is located above the cathode for the dual-chamber battery;

[0010] The single-chamber microbial battery comprises a single-chamber battery chamber and a resistor for a single-chamber battery, wherein an anode for a single-chamber battery and a cathode for a single-chamber battery are arranged in the single-chamber battery chamber;

[0011] The single-chamber battery chamber is provided with a single-chamber battery outlet and a single-chamber battery inlet, wherein the single-chamber battery outlet is located at the upper part of the single-chamber battery chamber, and the single-chamber battery inlet is opened at the lower part of the single-chamber battery chamber;

[0012] The first outlet of the dual-chamber battery is connected to the inlet of the single-chamber battery;

[0013] The first crystallization tank is provided with a first crystallization feed inlet, a first crystallization overflow discharge port and a first crystallization discharge port, wherein the first crystallization feed inlet is located at the upper part of the first crystallization tank, and the first crystallization discharge port is located at the lower part of the first crystallization tank; the second crystallization tank is provided with a second crystallization feed inlet and a second crystallization discharge port, wherein the second crystallization feed inlet is located at the upper part of the second crystallization tank, and the second crystallization discharge port is located at the lower part of the second crystallization tank; the first crystallization overflow discharge port is connected with the second crystallization feed inlet;

[0014] The second outlet of the double-chamber battery and the outlet of the single-chamber battery are both connected to the first crystallization feed inlet.

[0015] The above-mentioned simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system is characterized in that the anode material of the dual-chamber battery is graphite felt, graphite wool or carbon fiber brush, and the cathode material of the dual-chamber battery is a composite material.

[0016] The above-mentioned simultaneous nitrogen removal and phosphorus removal microbial battery wastewater treatment system is characterized in that the dual-chamber battery chamber includes a dual-chamber battery wall that encloses the dual-chamber battery inner cavity, the dual-chamber battery wall includes a dual-chamber battery first wall and a dual-chamber battery second wall, the dual-chamber battery first wall is close to the dual-chamber battery cathode, and the dual-chamber battery first wall is a waterproof and breathable membrane.

[0017] The above-mentioned simultaneous denitrification and phosphorus removal microbial battery sewage treatment system is characterized in that the anode used in the single-chamber battery is magnesium wire.

[0018] The above-mentioned simultaneous denitrification and phosphorus removal microbial battery wastewater treatment system is characterized in that the first crystallization overflow discharge port is connected to the second crystallization feed port through a pipeline.

[0019] The above-mentioned simultaneous denitrification and phosphorus removal microbial battery wastewater treatment system is characterized in that a first filter for a dual-chamber battery is provided at the first outlet of the dual-chamber battery, a second filter for a dual-chamber battery is provided at the second outlet of the dual-chamber battery, and a filter for a single-chamber battery is provided at the outlet of the single-chamber battery.

[0020] In addition, the present invention also provides a method for simultaneously removing nitrogen and phosphorus from sewage by using the above-mentioned simultaneous denitrification and dephosphorization microbial battery sewage treatment system, which is characterized by comprising:

[0021] Step 1: inject sewage into the double-chamber battery chamber, and the microorganisms in the sewage are attached to the double-chamber battery anode. The sewage of the double-chamber battery anode in the double-chamber battery chamber enters the single-chamber battery chamber through the first outlet of the double-chamber battery, and the attached microorganisms degrade organic matter in the sewage;

[0022] Step 2: When the ammonium ion concentration of the dual-chamber battery cathode system is ≥ 10 mmol / L, the dual-chamber battery cathode system is transferred to the first crystallization tank, and the dual-chamber battery anode system is transferred to the single-chamber battery chamber;

[0023] Step 3: The microorganisms degrade the organic matter in the system in the chamber of the single-chamber battery, and the anode of the single-chamber battery is oxidized to generate magnesium ions, thereby obtaining a system containing magnesium ions;

[0024] Step 4: After the single-chamber battery chamber has been running for 24 to 36 hours, the system containing magnesium ions is transferred to the first crystallization tank.

[0025] The above method is characterized in that, in step 1, the ammonium ion concentration in the sewage is 2mmol / L to 5mmol / L.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The synchronous denitrification and phosphorus removal microbial cell sewage treatment system of the present invention uses a double-chamber microbial cell, a single-chamber microbial cell, a first crystallization tank and a second crystallization tank, and is used for low C / N sewage treatment. It can remove ammonia nitrogen and phosphorus at the same time, without the need for additional nitrification and denitrification processes, and eliminates the need for aeration and oxygen supply. The treatment process can simultaneously obtain high-purity magnesium ammonium phosphate, diammonium hydrogen phosphate and diammonium dihydrogen phosphate, etc., which can be directly used as fertilizers. It has the characteristics of good sewage treatment effect and high recycling efficiency.

[0028] 2. The synchronous denitrification and phosphorus removal microbial battery sewage treatment system of the present invention includes a dual-chamber microbial battery comprising an anode for a dual-chamber battery, a cathode for a dual-chamber battery and a cation exchange membrane for a dual-chamber battery. The dual-chamber microbial battery can effectively enrich ammonium ions in sewage and remove heavy metal ions at the same time. Through the action of the electric field, it has the characteristics of high ammonium enrichment efficiency and good heavy metal and colloid filtration and removal effects.

[0029] 3. The synchronous denitrification and phosphorus removal microbial cell wastewater treatment system of the present invention comprises a single-chamber microbial cell comprising a single-chamber cell anode and a single-chamber cell cathode, and the magnesium ions generated by the single-chamber cell anode can be directly used as a raw material for analytical precipitation in the wastewater treatment process.

[0030] 4. The simultaneous denitrification and phosphorus removal microbial battery wastewater treatment method of the present invention performs preliminary treatment on the wastewater through a double-chamber battery chamber, and then enters a single-chamber battery chamber to further degrade organic matter in the wastewater, thereby achieving simultaneous denitrification and phosphorus removal treatment of the wastewater. The two battery systems are used in combination to improve degradation and enrichment efficiency.

[0031] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] Instruction Manual

[0033] Figure 1 This is a schematic diagram of the structure of the simultaneous nitrogen and phosphorus removal microbial battery sewage treatment system in Example 1. DETAILED DESCRIPTION

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides a synchronous denitrification and dephosphorization microbial battery sewage treatment system, including a double-chamber microbial battery, a single-chamber microbial battery, a first crystallization tank 3 and a second crystallization tank 4;

[0036] The dual-chamber microbial battery comprises a dual-chamber battery chamber 11 and a dual-chamber battery resistor 12, wherein a dual-chamber battery anode 13, a dual-chamber battery cathode 14 and a dual-chamber battery cation exchange membrane 15 are arranged in the dual-chamber battery chamber 11, and the dual-chamber battery cation exchange membrane 15 is arranged between the dual-chamber battery anode 13 and the dual-chamber battery cathode 14;

[0037] The dual-chamber battery chamber 11 is provided with a dual-chamber battery inlet 16, a dual-chamber battery first outlet 17 and a dual-chamber battery second outlet 18, wherein the dual-chamber battery inlet 16 is located below the dual-chamber battery anode 13, the dual-chamber battery first outlet 17 is located above the dual-chamber battery anode 13, and the dual-chamber battery second outlet 18 is located above the dual-chamber battery cathode 14; a first filter 19 for the dual-chamber battery is provided at the first outlet 17 of the dual-chamber battery, and a second filter 110 for the dual-chamber battery is provided at the second outlet 18 of the dual-chamber battery;

[0038] The single-chamber microbial battery comprises a single-chamber battery chamber 21 and a single-chamber battery resistor 27, wherein a single-chamber battery anode 22 and a single-chamber battery cathode 23 are arranged in the single-chamber battery chamber 21;

[0039] The single-chamber battery chamber 21 is provided with a single-chamber battery outlet 24 and a single-chamber battery inlet 25, wherein the single-chamber battery outlet 24 is located at the upper part of the single-chamber battery chamber 21, and the single-chamber battery inlet 25 is opened at the lower part of the single-chamber battery chamber 21;

[0040] The first outlet 17 of the dual-chamber battery is connected to the inlet 25 of the single-chamber battery; the outlet 24 of the single-chamber battery is provided with a filter 26 for the single-chamber battery;

[0041] The first crystallization tank 3 is provided with a first crystallization feed port 31, a first crystallization overflow discharge port and a first crystallization discharge port 32, wherein the first crystallization feed port 31 is located at the upper part of the first crystallization tank 3, and the first crystallization discharge port 32 is located at the lower part of the first crystallization tank 3; the second crystallization tank 4 is provided with a second crystallization feed port 41 and a second crystallization discharge port 42, wherein the second crystallization feed port 41 is located at the upper part of the second crystallization tank 4, and the second crystallization discharge port 42 is located at the lower part of the second crystallization tank 4; the first crystallization overflow discharge port 32 is connected to the second crystallization feed port 41;

[0042] The second outlet 18 of the dual-chamber battery and the outlet 24 of the single-chamber battery are both connected to the first crystallization feed inlet 31. The second outlet 18 of the dual-chamber battery and the outlet 24 of the single-chamber battery are connected to the first crystallization feed inlet 31 in a specific manner that the outlet 24 of the single-chamber battery is connected to the first crystallization feed inlet 31 through a pipeline, and the second outlet 18 of the dual-chamber battery is connected to the pipeline. The connection point of the second outlet 18 of the dual-chamber battery on the pipeline is located between the filter 26 for the single-chamber battery and the outlet 24 of the single-chamber battery.

[0043] In this embodiment, the anode 13 for the dual-chamber battery is made of graphite felt, graphite wool or carbon fiber brush, and the cathode 14 for the dual-chamber battery is made of a composite material. The composite material includes a substrate and graphite felt carbon fiber coated on the substrate, the substrate is an EPTFE / PTFE waterproof breathable membrane, the graphite felt carbon fiber is a carbon fiber surface felt, the carbon content is greater than 98.8%, the ash content is less than 0.3%, and the bulk density is 0.08-0.1 g / cm 3 , specific surface area is 2.3~4m 2 / g, felt shedding rate is 2-3μg / (g felt), oxidation rate in air at 600℃ is less than 2.6%, porosity is 85-95%, surface resistance is 0.165-0.193mΩ / cm 2 , internal resistance 15.3 ~ 26.7mΩ, the EPTFE / PTFE waterproof breathable membrane is a polyethylene / polypropylene waterproof breathable membrane, composed of PP spunbond non-woven fabric, PE polymer breathable membrane and PP spunbond non-woven fabric, heat-resistant temperature of -40 ℃ ~ 100 ℃, air permeability ≥ 1500g / square / 24 hours; the composite material was purchased from Jiangsu Puxiang Environmental Protection Technology Co., Ltd.

[0044] The graphite felt is polyacrylonitrile PAN-based graphite felt purchased from Jiangsu Puxiang Environmental Protection Technology Co., Ltd.; the carbon fiber brush is a stainless steel brush coated with a carbon fiber coating, purchased from Shanghai Kajit Chemical Technology Co., Ltd., and the carbon fiber length is 3 mm;

[0045] In this embodiment, the dual-chamber microbial battery further includes a reflux pipeline for reflux the system in the cathode chamber of the dual-chamber battery where the cathode 14 of the dual-chamber battery is located to the cathode chamber of the dual-chamber battery.

[0046] In this embodiment, the dual-chamber battery chamber 11 includes a dual-chamber battery wall that encloses and forms the dual-chamber battery inner cavity, the dual-chamber battery wall includes a first dual-chamber battery wall and a second dual-chamber battery wall, the first dual-chamber battery wall is close to the dual-chamber battery cathode 14, and the first dual-chamber battery wall is a waterproof breathable membrane. Specifically, the first dual-chamber battery wall is close to the dual-chamber battery cathode 14 and faces the cation exchange membrane 15, the first dual-chamber battery wall is made of a waterproof breathable membrane, which is used to allow air to enter the dual-chamber cathode chamber, the second dual-chamber battery wall is organic glass, the dual-chamber cathode chamber is an oxygen-containing environment, and the dual-chamber anode chamber is an anaerobic environment. The cation exchange membrane 15 separates the dual-chamber anode chamber and the dual-chamber cathode chamber, the dual-chamber anode chamber has a volume of 250 mL, and the dual-chamber cathode chamber has a volume of 83 mL; specifically, the dual-chamber battery anode 13 is filled in the left side of the dual-chamber battery chamber 11 separated by the cation exchange membrane 15, and the dual-chamber battery cathode 14 is arranged on the right side of the dual-chamber battery chamber 11 separated by the cation exchange membrane 15, the left side serves as the dual-chamber anode chamber, and the right side serves as the dual-chamber cathode chamber.

[0047] The anode 22 for the single-chamber battery is magnesium wire, which is wound into a mesh and filled on the left side of the single-chamber battery chamber 21. The cathode 23 for the single-chamber battery is made of the same material as the cathode 14 for the double-chamber battery, and is arranged on the right side of the single-chamber battery chamber 21; the material of the single-chamber battery chamber 21 is the same as that of the double-chamber battery chamber 11, and the first wall of the single-chamber battery corresponding to the single-chamber battery chamber 21 is close to the cathode 23 for the single-chamber battery, which allows air to enter the single-chamber cathode chamber. The single-chamber cathode chamber is an oxygen-containing environment. Under the action of the single-chamber cathode electrochemical reduction reaction, oxygen is rapidly consumed, and the single-chamber anode chamber is an anaerobic environment.

[0048] In this embodiment, the dual-chamber battery anode 13 is electrically connected to the dual-chamber battery cathode 14 , and the dual-chamber battery resistor 12 is disposed between the dual-chamber battery anode 13 and the dual-chamber battery cathode 14 .

[0049] In this embodiment, the single-chamber battery anode 22 is electrically connected to the single-chamber battery cathode 23, and the single-chamber battery resistor 27 is disposed between the single-chamber battery anode 22 and the single-chamber battery cathode 23. The resistance values ​​of the dual-chamber battery resistor 12 and the single-chamber battery resistor 27 are both 50 ohms.

[0050] In this embodiment, the first crystallization overflow discharge port is connected to the second crystallization feed port 41 through a pipeline. The material in the first crystallization tank 3 can enter the second crystallization tank 4 through the first crystallization overflow discharge port; the first crystallization tank 3 is used to crystallize magnesium ammonium phosphate MgNH4PO4, and carbon dioxide is introduced into the second crystallization tank 4 to generate ammonium bicarbonate NH4HCO3. Completely remove NH4 in the sewage + .

[0051] The sides of the first crystallization tank 3 and the second crystallization tank 4 are both opened. The side opening of the first crystallization tank is the first crystallization overflow discharge port, which functions to discharge the overflow water in time and enter the second crystallization tank 4. Specifically, the liquid phase overflowing from the first crystallization overflow discharge port of the first crystallization tank 3 flows into the second crystallization tank 4 through the second crystallization feed port 41 of the second crystallization tank 4.

[0052] In this embodiment, the current density of the dual-chamber microbial battery is 2-6 mA / cm 2 The dual-chamber battery is used to enrich ammonium ions in sewage and remove heavy metal ions in sewage. The principle is that under the action of the electric field, NH4 + and Ca 2+ Migrate to the cathode of the double-chamber battery through the double-chamber battery cation exchange membrane 15, Ca 2+ Ca(OH)2 is deposited at the cathode of the dual-chamber battery, and NH4 is enriched at the cathode of the dual-chamber battery + After the double-chamber battery is used for the cathode 14 part to react with the battery, the system is enriched with NH4 + Before the system is transported to the first crystallization tank, Ca(OH)2 is filtered and removed, and after partial treatment with the anode 13 of the double-chamber battery, the system is transported to the single-chamber battery chamber 21 for the next reaction.

[0053] In this embodiment, the current density of the single-chamber microbial battery is 5-10 mA / cm 2 The single-chamber battery functions to remove organic matter from sewage and promote the single-chamber battery anode to participate in the reaction to obtain magnesium ions. The principle is that: under the action of the electric field, the single-chamber battery anode 22 of the single-chamber battery chamber 21 is electrolyzed to obtain Mg 2+ ,Mg 2+ Its function is to enter the crystallization tank as the raw material for producing magnesium ammonium phosphate.

[0054] Example 2

[0055] This embodiment provides a method for performing microbial cell denitrification and dephosphorization of sewage using the simultaneous denitrification and dephosphorization microbial cell sewage treatment system described in Embodiment 1, specifically comprising:

[0056] Step 1, the sewage is transferred to the double-chamber battery chamber 11, and part of the sewage in the double-chamber battery anode 13 in the double-chamber battery chamber 11 enters the single-chamber battery chamber 21 through the first outlet 17 of the double-chamber battery; the sewage is transferred to the double-chamber battery chamber 11 through the double-chamber battery inlet 16, and the sewage is transferred to the double-chamber anode chamber of the double-chamber battery chamber 11, and the volume of the double-chamber anode chamber is 3.1 times the volume of the double-chamber cathode chamber; the sewage volume is 3.1 times the volume of the double-chamber cathode chamber; the sewage is the sewage after the first sedimentation of the sewage plant, and the ammonium ion concentration in the sewage is 2mmol / L~5mmol / L; the sewage after the first sedimentation is the sewage after removing the sediment and other parts that are difficult to degrade by organisms, so as to achieve solid-liquid separation; in this embodiment, the sewage volume is 250mL, and the volume of the double-chamber cathode chamber is 80mL;

[0057] Step 2: The microorganisms in the sewage are attached to the anode 13 for the dual-chamber battery. Under the anaerobic environment, the microorganisms at the anode 13 for the dual-chamber battery degrade the organic matter in the sewage. The generated electrons are transferred to the cathode 14 for the dual-chamber battery through the external circuit. The protons are transferred to the cathode chamber of the dual-chamber battery where the cathode 14 for the dual-chamber battery is located through the cation exchange membrane 15, and combine with the electron acceptor to degrade the organic matter and generate electricity until the current density of the dual-chamber microbial battery is stabilized at 2-6 mA / cm 2 , and obtain the domesticated system; the double-chamber battery uses the anode reaction: organic matter + H2O → CO2 + H + +e - ; Double chamber battery cathode reaction: O2+H2O+e - →OH - ; The microorganism is an electrogenic bacterium, which is a common electrogenic bacterium in the art, such as Geobacter, or Proteobacteria, Deltaproteobacteria, Shewanella or Geobacter; the time to obtain the domesticated system is generally 1 to 2 weeks;

[0058] Step 3, sampling the system in the cathode chamber of the dual-chamber battery where the dual-chamber battery cathode 14 is located, and conducting an ammonium ion concentration test, until the ammonium ion concentration is ≥10mmol / L, a part of the system in the cathode chamber of the dual-chamber battery where the dual-chamber battery cathode 14 is located is transferred to the first crystallization tank 3, and the other part is refluxed to the cathode chamber of the dual-chamber battery where the dual-chamber battery cathode 14 is located; the time required to reach the ammonium ion concentration ≥10mmol / L is 12h~24h, the organic matter in the sewage is degraded by 60%~80%, and Ca(OH)2 is removed by filtration;

[0059] Step 4: Under the action of the double-chamber battery anode indoor system, the single-chamber battery anode 22 in the single-chamber battery chamber 21 is oxidized to generate magnesium ions, thereby obtaining a system containing magnesium ions, and the generated electrons are transmitted to the single-chamber battery cathode 23 through an external circuit; the microorganisms in the double-chamber battery anode indoor system degrade organic matter in the sewage, oxidize the single-chamber battery anode 22, and simultaneously reduce the organic matter in the sewage and generate magnesium ions;

[0060] Step 5, when the magnesium ion concentration of the effluent in the single-chamber battery outlet 24 is 2-2.5 mg / L, the system containing magnesium ions is transferred to the first crystallization tank 3 for the first crystallization. After the first crystallization, the product flows out from the first crystallization discharge port 32 for standby use. After the first crystallization, the liquid phase overflows from the first crystallization overflow discharge port and enters the second crystallization tank 4 for the second crystallization to complete the denitrification and phosphorus removal of the sewage. The operation time when the magnesium ion concentration of the effluent in the single-chamber battery outlet 24 is 2-2.5 mg / L is 24h-36h;

[0061] The results show that after the wastewater is treated by the method of this embodiment, the purity of the magnesium ammonium phosphate produced by crystallization is 86%, the purity of diammonium hydrogen phosphate is 81%, and the purity of ammonium dihydrogen phosphate is 75%. By filling the second crystallization tank with carbon dioxide, the formation of ammonium bicarbonate can be further promoted, and the purity of ammonium bicarbonate can reach up to 92%, thereby achieving complete removal of ammonium ions.

[0062] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A simultaneous denitrification and phosphorus removal microbial battery sewage treatment system, characterized in that: It comprises a double-chamber microbial battery, a single-chamber microbial battery, a first crystallization tank (3) and a second crystallization tank (4); The dual-chamber microbial battery comprises a dual-chamber battery chamber (11) and a dual-chamber battery resistor (12); a dual-chamber battery anode (13), a dual-chamber battery cathode (14) and a dual-chamber battery cation exchange membrane (15) are arranged in the dual-chamber battery chamber (11); the dual-chamber battery cation exchange membrane (15) is arranged between the dual-chamber battery anode (13) and the dual-chamber battery cathode (14); The dual-chamber battery chamber (11) is provided with a dual-chamber battery inlet (16), a dual-chamber battery first outlet (17) and a dual-chamber battery second outlet (18); the dual-chamber battery inlet (16) is located below the dual-chamber battery anode (13); the dual-chamber battery first outlet (17) is located above the dual-chamber battery anode (13); and the dual-chamber battery second outlet (18) is located above the dual-chamber battery cathode (14); The single-chamber microbial battery comprises a single-chamber battery chamber (21) and a single-chamber battery resistor (27), wherein a single-chamber battery anode (22) and a single-chamber battery cathode (23) are arranged in the single-chamber battery chamber (21); The single-chamber battery chamber (21) is provided with a single-chamber battery outlet (24) and a single-chamber battery inlet (25), wherein the single-chamber battery outlet (24) is located at the upper part of the single-chamber battery chamber (21), and the single-chamber battery inlet (25) is opened at the lower part of the single-chamber battery chamber (21); The first outlet (17) of the dual-chamber battery is in communication with the inlet (25) of the single-chamber battery; The first crystallization tank (3) is provided with a first crystallization feed inlet (31), a first crystallization overflow discharge port and a first crystallization discharge port (32), wherein the first crystallization feed inlet (31) is located at the upper part of the first crystallization tank (3), and the first crystallization discharge port (32) is located at the lower part of the first crystallization tank (3); the second crystallization tank (4) is provided with a second crystallization feed inlet (41) and a second crystallization discharge port (42), wherein the second crystallization feed inlet (41) is located at the upper part of the second crystallization tank (4), and the second crystallization discharge port (42) is located at the lower part of the second crystallization tank (4); the first crystallization overflow discharge port is connected to the second crystallization feed inlet (41); The second outlet (18) of the dual-chamber battery and the outlet (24) of the single-chamber battery are both connected to the first crystallization feed port (31).

2. The simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system according to claim 1 is characterized in that: The material of the anode (13) for the dual-chamber battery is graphite felt, graphite wool or carbon fiber brush, and the material of the cathode (14) for the dual-chamber battery is a composite material.

3. The simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system according to claim 1 is characterized in that: The dual-chamber battery chamber (11) includes a dual-chamber battery wall surface that encloses and forms an inner cavity of the dual-chamber battery. The dual-chamber battery wall surface includes a dual-chamber battery first wall surface and a dual-chamber battery second wall surface. The dual-chamber battery first wall surface is close to a dual-chamber battery cathode (14). The dual-chamber battery first wall surface is a waterproof and breathable membrane.

4. The simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system according to claim 1 is characterized in that: The anode (22) for the single-chamber battery is a magnesium wire.

5. The simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system according to claim 1 is characterized in that: The first crystallization overflow discharge port is connected to the second crystallization feed port (41) by a pipeline.

6. The simultaneous nitrogen removal and phosphorus removal microbial battery sewage treatment system according to claim 1 is characterized in that: A first filter (19) for a dual-chamber battery is provided at the first outlet (17) of the dual-chamber battery, a second filter (110) for a dual-chamber battery is provided at the second outlet (18) of the dual-chamber battery, and a filter (26) for a single-chamber battery is provided at the outlet (24) of the single-chamber battery.

7. A method for simultaneous denitrification and dephosphorization of sewage using the simultaneous denitrification and dephosphorization microbial battery sewage treatment system as claimed in claim 1, characterized in that: include: Step 1: inject sewage into the dual-chamber battery chamber (11), microorganisms in the sewage adhere to the dual-chamber battery anode (13), part of the sewage in the dual-chamber battery anode (13) in the dual-chamber battery chamber (11) enters the single-chamber battery chamber (21) through the first outlet (17) of the dual-chamber battery, and the attached microorganisms degrade organic matter in the sewage; Step 2: When the ammonium ion concentration of the system in the cathode (14) for the dual-chamber battery is ≥ 10 mmol / L, the system in the cathode (14) for the dual-chamber battery is transferred to the first crystallization tank (3); Step 3: Microorganisms degrade organic matter in the system in the single-chamber battery chamber (21), and the single-chamber battery anode (22) is oxidized to generate magnesium ions, thereby obtaining a system containing magnesium ions; Step 4: transport the system containing magnesium ions to the first crystallization tank (3).

8. The method according to claim 7, characterized in that In step 1, the ammonium ion concentration in the sewage is 2 mmol / L to 5 mmol / L.

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