阅读说明：本技术 空气阴极生物电化学系统辅助正渗透膜生物反应器的水处理装置及水处理方法 (Water treatment device and water treatment method of air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor ) 是由 杨玉立 吴忧 于 2021-08-10 设计创作，主要内容包括：本发明公开一种空气阴极生物电化学系统辅助正渗透膜生物反应器的水处理装置及水处理方法,水处理装置的反应池包括阳极室和汲取液室,两者通过正渗透膜分隔；阳极室一侧设有空气阴极,其与阳极室通过玻璃纤维膜分隔。水处理方法中,阳极室的厌氧污泥降解有机物质产生电子传递到阴极；阴极处的氧气与电子、质子结合生成水,此过程产生电能；阴极处同时发生硝化过程,电流驱动硝酸根离子迁移到厌氧阳极处,阳极的厌氧微生物利用反渗的有机汲取液作为反硝化的碳源,将硝酸根反硝化成为氮气；阳极室中的部分水分子通过正渗透膜进入汲取液侧。本发明脱氮效率高,能够降低进料液侧出水中的污染物浓度；此外,空气阴极无需曝气,节约能源,降低成本。(The invention discloses a water treatment device and a water treatment method of an air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor, wherein a reaction tank of the water treatment device comprises an anode chamber and a drawing liquid chamber which are separated by a forward osmosis membrane; one side of the anode chamber is provided with an air cathode which is separated from the anode chamber by a glass fiber membrane. In the water treatment method, anaerobic sludge in the anode chamber degrades organic substances to generate electrons which are transferred to the cathode; the oxygen at the cathode is combined with electrons and protons to generate water, and the process generates electric energy; the nitrification process is simultaneously carried out on the cathodes, the current drives nitrate ions to migrate to the anaerobic anodes, and the anaerobic microorganisms on the anodes utilize the reverse osmosis organic draw solution as a denitrification carbon source to denitrify the nitrate into nitrogen; part of water molecules in the anode chamber enter the drawing liquid side through the forward osmosis membrane. The invention has high denitrification efficiency and can reduce the concentration of pollutants in the effluent of the feed liquid side; in addition, the air cathode does not need aeration, thereby saving energy and reducing cost.)

1. The utility model provides a water treatment facilities of supplementary forward osmosis membrane bioreactor of air cathode bioelectrochemistry system which characterized in that: the device comprises a reaction tank (1), wherein the reaction tank (1) comprises an anode chamber (101) and a draw liquid chamber (103), and the anode chamber (101) is separated from the draw liquid chamber (103) through a forward osmosis membrane (105); an air cathode (102) is arranged on one side of the anode chamber (101), and the air cathode (102) is separated from the anode chamber (101) through a glass fiber membrane (104); one side of the forward osmosis membrane (105) close to the anode chamber (101) is a feeding side, and one side close to the drawing liquid chamber (103) is a drawing liquid side; an anode (106) is arranged in the anode chamber (101), and the anode (106) is connected with the anode of an external data acquisition card; the bottom of the anode chamber (101) is provided with a water inlet (107), and the top is provided with a water outlet (108).

2. The water treatment apparatus according to claim 1, characterized in that: the device also comprises a raw material liquid tank (2), wherein the raw material liquid tank (2) is internally filled with anolyte, and the anolyte is municipal sewage containing activated sludge or manual water distribution; the water inlet (107) and the water outlet (108) are respectively connected with the raw material liquid tank (2) through pipelines.

3. The water treatment apparatus according to claim 2, characterized in that: a first peristaltic pump (4) is arranged on a pipeline between the raw material liquid tank (2) and the water inlet (107), the first peristaltic pump (4) pumps the anolyte in the raw material liquid tank (2) into the anode chamber (101), and the anolyte flows out through the water outlet (108) and circulates into the raw material liquid tank (2).

4. The water treatment apparatus according to claim 1, characterized in that: the device also comprises a liquid drawing tank (3), wherein the liquid drawing tank (3) is filled with drawing liquid, and the drawing liquid is sodium acetate; the drawing liquid inlet (109) and the drawing liquid outlet (110) are respectively connected with the drawing liquid tank (3) through pipelines.

5. The water treatment apparatus according to claim 4, characterized in that: a second peristaltic pump (5) is arranged on a pipeline connected with the drawing liquid tank (3) through the drawing liquid inlet (109), the drawing liquid in the drawing liquid tank (3) is pumped into the drawing liquid chamber (103) through the second peristaltic pump (5), and the drawing liquid is discharged through the drawing liquid outlet (110).

6. The water treatment apparatus according to claim 1, characterized in that: and a stirring device (6) is arranged at the bottom of the drawing liquid chamber (103) and/or the anode chamber (101).

7. The water treatment apparatus according to claim 1, characterized in that: the active side of the forward osmosis membrane (105) faces the anode chamber (101).

8. The water treatment apparatus according to claim 1, characterized in that: the anode (106) material is carbon brush.

9. The water treatment apparatus according to claim 1, characterized in that: the air cathode (102) is made of waterproof carbon paper.

10. A water treatment method based on the water treatment device as claimed in any one of claims 1 to 9, comprising the steps of:

s1, connecting the anode with the anode of an external data acquisition card, connecting the cathode with the cathode of the external data acquisition card, pumping the anolyte into the anode chamber, pumping the draw liquid into the draw liquid chamber, operating the draw liquid and the anolyte at a preset circulating flow rate, and feeding water into the anode chamber in batches; the anolyte is municipal sewage or artificial water distribution containing anaerobic sludge degradation organic substances, and the drawing liquid is sodium acetate;

s2, degrading organic matters by anaerobic sludge in the anode chamber to generate electrons, and transferring the electrons to the cathode through an external circuit; at the air cathode, the diffused oxygen is combined with electrons and protons to generate water, and the process generates electric energy; a nitrification process is simultaneously carried out on the air cathode, ammonia nitrogen is oxidized into nitrate nitrogen, current drives nitrate ions to migrate to the anaerobic anode, and anaerobic microorganisms on the anode utilize reverse-osmosis organic draw solution as a denitrification carbon source to denitrify the nitrate nitrogen into nitrogen; part of water molecules in the anode chamber enter the drawing liquid side through the forward osmosis membrane.

Technical Field

The invention relates to the technical field of water treatment, in particular to a water treatment device of an air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor, and also relates to a water treatment method of the air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor.

Background

Forward Osmosis Membrane Bioreactors (OMBRs) are a Membrane-based treatment technology that recover high quality water from wastewater by Forward Osmosis (FO). Microbial Fuel Cells (MFCs) are capable of degrading pollutants in wastewater using electrogenic microorganisms as catalysts, while directly converting chemical energy in the wastewater pollutants into electrical energy. The permeable microbial fuel cell system combines a forward permeable membrane with a traditional microbial fuel cell, and is mainly applied to solving the problem of membrane pollution of OMBR and improving the permeability of the system. Wherein, the forward osmosis membrane is asymmetric structure, comprises active layer and supporting layer, and the high concentration solution is placed as drawing the liquid to one side that is close to the supporting layer, and the feed solution of low concentration is placed to one side that is close to the active layer, produces osmotic pressure under the effect of concentration difference, orders about the water of feed solution side and permeates the semi-permeable membrane, draws the liquid and is diluted, and follow-up can draw the liquid to the dilution and separate, obtains pure play water. If the OMBR is connected to a Microbial Electrolysis Cell (MEC), the technical effect of reducing membrane fouling in an electric field can be achieved. In the MEC-FO system, ammonium recovered by MECs from high strength synthetic wastewater is used as a draw solute in a subsequent FO unit that recovers ammonia nitrogen while obtaining reuse water from the MECs. However, as yet, BES (bioelectrochemistry) has not been studied to address the problem of low denitrification efficiency in FO-based treatment systems.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention aims to provide a water treatment device of an air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor, and the invention also aims to provide a water treatment method of the air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor.

The technical scheme is as follows: a water treatment device of an air cathode bioelectrochemical system auxiliary forward osmosis membrane bioreactor comprises a reaction tank, wherein the reaction tank comprises an anode chamber and a drawing liquid chamber, and the anode chamber and the drawing liquid chamber are separated by a forward osmosis membrane; an air cathode is arranged on one side of the anode chamber, and the air cathode is separated from the anode chamber through a glass fiber membrane; one side of the forward osmosis membrane close to the anode chamber is a feeding side, and one side close to the liquid drawing chamber is a liquid drawing side; an anode is arranged in the anode chamber and is connected with the anode of an external data acquisition card; the bottom of the anode chamber is provided with a water inlet, and the top of the anode chamber is provided with a water outlet.

The system further comprises a raw material liquid tank, wherein the raw material liquid tank is filled with anolyte, and the anolyte is municipal sewage containing activated sludge or artificial water distribution; the water inlet and the water outlet are respectively connected with the raw material liquid tank through pipelines. And a first peristaltic pump is arranged on a pipeline between the raw material liquid tank and the water inlet, the first peristaltic pump pumps the anolyte in the raw material liquid tank into the anode chamber, and the anolyte flows out through the water outlet and circulates into the raw material liquid tank.

Further, the device also comprises a liquid drawing tank, wherein the liquid drawing tank is filled with drawing liquid, and the drawing liquid is sodium acetate; the drawing liquid inlet and the drawing liquid outlet are respectively connected with the drawing liquid tank through pipelines. And a second peristaltic pump is arranged on a pipeline connecting the drawing liquid inlet and the drawing liquid tank, the second peristaltic pump pumps the drawing liquid in the drawing liquid tank into the drawing liquid chamber, and the drawing liquid is discharged through the drawing liquid outlet.

Further, the bottom of the drawing liquid chamber and/or the anode chamber is provided with a stirring device.

Further, the active side of the forward osmosis membrane faces the anode chamber.

Preferably, the anode material is a carbon brush. The air cathode material is waterproof carbon paper.

A water treatment method based on the water treatment device comprises the following steps:

s1, connecting the anode with the anode of an external data acquisition card, connecting the cathode with the cathode of the external data acquisition card, pumping the anolyte into the anode chamber, pumping the draw liquid into the draw liquid chamber, operating the draw liquid and the anolyte at a preset circulating flow rate, and feeding water into the anode chamber in batches; the anolyte is municipal sewage or artificial water distribution containing anaerobic sludge degradation organic substances, and the drawing liquid is sodium acetate;

s2, degrading organic matters by anaerobic sludge in the anode chamber to generate electrons, and transferring the electrons to the cathode through an external circuit; at the air cathode, the diffused oxygen is combined with electrons and protons to generate water, and the process generates electric energy; a nitrification process is simultaneously carried out on the air cathode, ammonia nitrogen is oxidized into nitrate nitrogen, current drives nitrate ions to migrate to the anaerobic anode, and anaerobic microorganisms on the anode utilize reverse-osmosis organic draw solution as a denitrification carbon source to denitrify the nitrate nitrogen into nitrogen; part of water molecules in the anode chamber enter the drawing liquid side through the forward osmosis membrane.

Has the advantages that:

compared with the prior art, the invention has the following remarkable advantages:

in order to solve the problem of low denitrification efficiency of OMBR, the invention provides a device and a method for synchronous nitrification and denitrification and forward osmosis membrane bioreactor salt reverse osmosis carbon source supplement enhanced denitrification, which adopt the coupling combined action of nitrifying bacteria, denitrifying bacteria and electrogenesis microorganisms. The raw material side of the OMBR is not only a biological reaction main body, but also an anode of a bioelectrochemical system, nitrate radicals obtained by cathode oxidation are driven to enter an anode chamber for denitrification through electrogenesis, denitrification is realized, BES assistance enables a drawing liquid to reversely permeate into an organic drawing liquid on the feed liquid side for electrogenesis, and the microbial decontamination capability of the OMBR is improved. In addition, the OMBR can concentrate organic matters and ammonia nitrogen in a feeding solution, strengthen the power generation of a bioelectrochemical system, and strengthen the synchronous nitrification and denitrification of the system, thereby improving the denitrification efficiency and reducing the concentration of pollutants in the effluent of the feeding solution. In addition, the air cathode does not need aeration, thereby saving energy and reducing cost.

Drawings

FIG. 1 is a block diagram of a water treatment plant of an air cathode bioelectrochemical system assisted forward osmosis membrane bioreactor;

FIG. 2 is a structural view of the reaction cell in FIG. 1.

Detailed Description

The invention will be further elucidated with reference to the following specific examples.

As shown in fig. 1 and fig. 2, the water treatment device of the air cathode bioelectrochemical system assisted forward osmosis membrane bioreactor of the present invention includes a reaction tank 1, a raw material liquid tank 2, a draw liquid tank 3 and a communication pipeline.

The reaction tank 1 comprises two compartments, an anode compartment 101 and a draw solution compartment 103, wherein one side of the anode compartment 101 is provided with an air cathode 102, the volumes of the two compartments are both 50ml, and the surface area of the air cathode carbon paper is 0.0025m²(ii) a The air cathode 102 and the anode chamber 101 are separated by a glass fiber membrane 104, the anode chamber 101 and the drawing liquid chamber 103 are separated by a forward osmosis membrane 105, the side of the forward osmosis membrane 105 close to the anode chamber 101 is a feeding side, and the side close to the drawing liquid chamber 103 is a drawing liquid side. In this example, the forward osmosis membrane 105 has a total permeation area of 0.0025m²The active side of the membrane composite of (1) facing the anode chamber 101, the forward osmosis membrane 105 and the glass fiber membrane 104 may be conventional products in the art.

An anode 106 is arranged in the anode chamber 101, the anode 106 is made of carbon brush (which can be non-moisture-proof), and the anode 106 is connected with the anode of an external data acquisition card through a lead. The bottom of the anode chamber 101 is provided with a water inlet 107, the top is provided with a water outlet 108, and the water inlet 107 and the water outlet 108 are respectively connected with the raw material liquid tank 2 through pipelines. The raw material liquid tank 2 is filled with anolyte, and the anolyte can be municipal sewage containing activated sludge or manual water distribution. A first peristaltic pump 4 is arranged on a pipeline between the raw material liquid tank 2 and the water inlet 107, the first peristaltic pump 4 pumps the anolyte in the raw material liquid tank 2 into the anode chamber 101, and the anolyte flows out through the water outlet 108 and circulates to the raw material liquid tank 2.

The cathode material of air cathode 102 is preferably a 5cm x 5cm waterproof carbon paper (heson HCP135) coated with a gas diffusion layer, a support layer, and a carbon-based layer.

The bottom of the drawing liquid chamber 103 is provided with a drawing liquid inlet 109, the top is provided with a drawing liquid outlet 110, the drawing liquid inlet 109 and the drawing liquid outlet 110 are respectively connected with the drawing liquid tank 3 through pipelines, and a second peristaltic pump 5 is arranged on the pipeline connecting the drawing liquid inlet 109 and the drawing liquid tank 3. The second peristaltic pump 5 pumps the draw solution in the draw solution tank 3 into the draw solution chamber 103, and the draw solution is discharged through the draw solution outlet 110. The stirring device 6 is provided at the bottom of both the dipping liquid chamber 103 and the anode chamber 101.

The water treatment is carried out by applying the device, and the steps are as follows:

in this example, the anolyte was artificially synthesized wastewater and activated sludge in a volume ratio of 9: 1, preparation, composition of artificially synthesized wastewater: 300 +/-1 mg.L^-1Sodium acetate (800 + -13 mg. L)^-1COD)，40±2mg·L^-1NH₄-N，15mg·L^{- 1}MgSO₄，20mg·L^-1CaCl₂，500mg·L^-1NaCl，100mg·L^-1NaHCO₃，5.35mg·L^-1K₂HPO₄，2.65mg·L^-1KH₂PO₄And 1 mL. L^-1Trace elements [ 1 liter of distilled water containing 50g FeCl₂·4H₂O,1.25g ZnCl₂,12.5g MnCl₂·4H₂O,1.25g(NH₄)₆Mo₉O₂₄.4H₂O,3.75g CoCl₂·6H₂O,2.5g NiCl₂·6H₂O,0.75g CuCl₂·2H₂O,1.25g H₃BO₃H ]; anaerobic activated sludge 100mL sludge from anaerobic digesters (69.62 g. L)^-1Mixed liquid suspension, VSS/SS ratio 87.53%); the draw solution is sodium acetate (the concentration is 1 mol.L)^-1)。

Connecting the anode with the anode of an external data acquisition card, connecting the cathode with the cathode of the external data acquisition card, pumping the anolyte in a raw material liquid tank into an anode chamber, pumping the draw liquid in a draw liquid tank into a draw liquid chamber, wherein the draw liquid and the anolyte are pumped at a speed of 96mL per minute^-1The circulation flow rate is operated, and water is fed into the anode chamber in sequence in a batch mode with the hydraulic retention time of 24 hours as a period. When the device is operated, the anaerobic sludge in the anode chamber degrades organic substances, and electrons are generated and transferred to the cathode through an external circuit. At the air cathode, the diffused oxygen is combined with electrons and protons to generate water, and the process generates electric energy; the nitrification process is simultaneously carried out on the air cathode, the ammonia nitrogen is oxidized into nitrate nitrogen, the current drives nitrate ions to migrate to the anaerobic anode, and the anaerobic microorganisms on the anode utilize the reverse-osmosis organic draw solution as a denitrification carbon source to denitrify the nitrate nitrogen into nitrogen. The cathode and the anode are separated by a glass fiber membrane to prevent short circuit, and the air cathode is continuously communicated without aerationAnd introducing air. Part of water molecules in the anode chamber enter the drawing liquid side through the forward osmosis membrane. In this way, the organic draw solution that has reverse-permeated the forward osmosis membrane draw solution side is consumed in the bioreactor, maintaining a relatively low COD. In addition, the forward osmosis membrane can concentrate organic substances and ammonia nitrogen substrates in a feeding solution, so that the power generation of the bioelectrochemical system is enhanced, and the generation of synchronous nitrification and denitrification is further promoted. After the operation is finished, the COD removal rate of the anode chamber is 97.88 +/-2.40%, the ammonia nitrogen removal rate is 78.29 +/-1.98%, the total nitrogen removal rate is 73.96 +/-0.50%, the produced total coulombs are 94.64 +/-4.7C, the recovered water amount is 438.20 +/-9.62 mL, the initial water flux is 5.36 +/-1.26 LMH, and the water flux after the operation for 24 hours is 1.5 +/-1.02 LMH.

The operation time of the embodiment of the invention is 24 hours, and for comparing the effects of different operation times, the operation is respectively carried out under the concentrations of 12 hours, 24 hours, 36 hours and 48 hours, the removal efficiency of nitrogen and COD is greatly improved along with the extension of the operation time, the removal efficiency of ammonia nitrogen is improved to 99.71 +/-0.03% from 60.37 +/-3.22%, the removal efficiency of total nitrogen is improved to 93.08 +/-0.93% from 57.37 +/-2.63%, and the removal efficiency of COD is improved to 92.51 +/-6.87% from 88.28 +/-5.61%. The total coulomb and the water recovery amount are respectively improved, the total coulomb is improved from 90.37 +/-6.35C to 137.35 +/-18.13C, and the water recovery amount is improved from 260.87 +/-10.32 mL to 529.87 +/-25.24 mL. This result demonstrates that extended run times help to increase nitrogen removal efficiency of the coupled system, and enable higher water recovery and higher bioelectric power generation.

In the embodiment of the invention, the drawing liquid is 1M sodium acetate, and in order to compare the effects of the drawing liquid with different concentrations, the drawing liquid is respectively implemented under the concentrations of 1M, 2M and 3M, and compared with 1M, 2M and 3M, the ammonia nitrogen removal rates are higher and closer, and are respectively 99.44 +/-0.05% and 99.76 +/-0.41%. The higher the concentration of the drawing liquid is, the better the removal effect of the total nitrogen is, the concentration of the drawing liquid is improved from 1M to 3M, and the removal rate of the total nitrogen is increased from 73.96 +/-0.50% to 95.58 +/-0.02%. The concentration of the draw solution is increased, the COD removal rate is slightly reduced, and the COD removal rates under the three draw solution conditions are respectively 97.88 +/-2.40%, 93.37 +/-0.14% and 94.34 +/-0.00%. The initial water fluxes of the three draw solutions were 5.36. + -. 1.26LMH, 5.5. + -. 0.53LMH and 7.45. + -. 0.23LMH, respectively, the water fluxes gradually decreased during the 24-hour operation, and after 24 hours, the water fluxes were 5.36. + -. 1.26LMH, 5.5. + -. 0.53LMH and 7.45. + -. 0.23LMH, respectively. Under the three conditions of the draw solution, the total water recovery amount is 438.20 +/-9.62 mL, 741.20 +/-52.89 mL and 748.13 +/-35.45 mL respectively, and the generated electric energy is 90.37 +/-6.35C, 152.56 +/-18.23C and 159.15 +/-19.52C respectively. This result indicates that a proper increase in the concentration of the draw solution can greatly increase the nitrogen removal efficiency of the coupled system, and can achieve a higher water recovery and generate higher bioelectricity, but an excessive increase in the concentration of the draw solution may not achieve better treatment effect and yield.

In summary, the water treatment device and method of the air cathode bioelectrochemical system assisted forward osmosis membrane bioreactor are used by connecting the forward osmosis membrane bioreactor with a bioelectrochemical device, nitrifying bacteria of an air cathode oxidize ammonia nitrogen in anolyte to nitrate nitrogen, active bacteria of an anode oxidize organic substances to generate electrons, the movement of the electrons drives ions between the cathode and the anode to move, and the nitrate is promoted to move towards the anode, so that denitrification is carried out under the anaerobic environment of the anode, and a reversely diffused organic solute is used as a substrate for denitrification and electricity generation, so that the denitrification efficiency and the electricity generation performance are improved.