CN209957483U - Split type wetland plant-microbial fuel cell coupling device - Google Patents

Abstract

The utility model relates to a split type wetland plant-microbial fuel cell coupling device, with plant and battery anode, the cathode separation, nitrify and the denitrification is gone on around two local divisions of difference, waste water flows out to be led to aerobic reactor after P-MFC anodic oxidation, utilize water free oxygen and plant roots to secrete oxygen and accomplish nitration process, the negative pole that flows into P-MFC afterwards carries out the electrochemistry denitrification under the oxygen deficiency condition, thereby the influence of oxygen to the negative pole denitrification process has been avoided, secrete oxygen with plant roots and promote the effect maximize of nitrifying/denitrifying. The contradiction between the promotion of the root system oxygen secretion to the nitrification and the inhibition of the denitrification can be well solved by adding the external cathode nitrification reactor of the plant.

Description

A split wetland plant-microbial fuel cell coupling device

technical field

The utility model belongs to the field of plant microbial fuel cells, in particular to a split wetland plant-microbial fuel cell which can improve the denitrification effect.

Background technique

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Today, ammonia nitrogen has become an important indicator of water pollution. Nitrogen in water exists in the form of organic nitrogen and inorganic nitrogen. Industrial wastewater, agricultural wastewater and domestic sewage are the main sources of these nitrogens. With the development of human society, the concentration of ammonia nitrogen in the water body is getting higher and higher, the eutrophication of the water body is intensified, endangering aquatic animals, destroying the ecological balance, and finally endangering human health and causing serious economic losses.

Plant-microbial fuel cell (P-MFC) is an emerging wastewater treatment process that can degrade nitrogen and generate electricity through a series of microbial cycle processes such as mineralization, nitrification, and denitrification. There are two main types of P-MFCs currently constructed. One is to use the plant root zone as the anode system of the battery, and the root zone exudates are used to solve the fuel problem of the MFC; the other is to use wetland plants to construct a bio-cathode microbial fuel cell. Its essence is to construct an aerobic bio-cathode microbial fuel cell by utilizing the oxygen exuded from the root system, and simultaneously complete the nitrification and denitrification processes at the cathode. In the cathode, although the root micro-oxygen environment will promote nitrification, because the redox potential of _O2 produced by plants is higher than that of _NO3- ^, _O2 will compete with _NO3- ^for protons and electrons, inhibiting the denitrification ^of _NO3- effect, reducing the denitrification rate. If the contradiction between the promotion of nitrification and the inhibition of denitrification by root oxygen secretion cannot be resolved, the promotion of plant oxygen secretion on denitrification cannot be maximized.

Utility model content

In order to overcome the above problems, the present invention provides a split-type wetland plant-microbial fuel cell coupling device. This problem can be well solved by adding plants to the external cathode nitrification reactor, which separates plants from the anode and cathode of the battery, nitrification and denitrification are carried out in two different places before and after, and the wastewater flows out after P-MFC anodization. It is guided to the aerobic reactor, and the nitrification is completed by using the free oxygen in the water body and the oxygen secreted by the plant roots, and then flows into the cathode of the P-MFC for electrochemical denitrification under anoxic conditions, thus avoiding the influence of oxygen on the cathode denitrification process. Oxygen secretion from plant roots maximizes the effect of nitrification and denitrification.

In order to realize the above-mentioned technical purpose, the technical scheme that the utility model adopts is as follows:

A split-type wetland plant-microbial fuel cell coupling device, comprising: an anode chamber, a cathode chamber, and an external aerobic reactor, the anode chamber is connected to one side of the cathode chamber through a cation exchange membrane, and the anode chamber is provided with an inlet A water outlet and a water outlet, the water outlet is connected with the water inlet of the external aerobic reactor, the water outlet of the external aerobic reactor is connected with the water inlet of the cathode chamber, and the cathode chamber is also provided with a water outlet, the Both the anode chamber and the cathode chamber are provided with graphite electrodes, and a load resistance is provided between the two electrodes. Using the above-mentioned split structure, the nitrification and denitrification processes can be separated to solve the effect of root oxygen secretion on the denitrification efficiency of P-MFC.

In some embodiments, one side of the anode chamber is abutted with the external aerobic reactor, and the water outlet of the anode chamber is higher than the water inlet of the external aerobic reactor, and is located on the abutted side wall. The power to make the wastewater flow comes from its own gravitational potential energy when it is transferred between the electrode chamber and the aerobic reactor, which can greatly reduce the consumption of energy and achieve the effect of energy saving.

In some embodiments, one side of the external aerobic reactor is abutted with one side of the cathode chamber, and the water outlet of the external aerobic reactor is higher than the water inlet of the cathode chamber and is located on the side wall of the aerobic reactor. . Utilize the height difference between the two to make wastewater flow, reduce energy consumption, and reduce unnecessary pipeline connections.

In some embodiments, a resistance is provided between the electrodes. The resistance can effectively limit and adjust the current size, and when the instantaneous current is too large, the short circuit phenomenon can be avoided.

The current of the plant power generation system is restricted by many factors such as the internal structure of the system, the growth state of plants and microorganisms, and the operating conditions. Different plant power generation systems have large differences in the magnitude of the power generation current. Therefore, in some embodiments, the external aerobic reactor is a wet plant, such as reed, canna, calamus, etc., so as to improve the activity of microorganisms in the rhizosphere of the plant and promote the improvement of the power generation performance of the system.

In some embodiments, the anode chamber is inoculated with the anaerobic digestion sludge of the municipal sewage treatment plant, and the inoculation amount is 50-200 mg/L;

In some embodiments, the cathode chamber is inoculated with the return sludge of the secondary sedimentation tank of the urban domestic sewage treatment plant, and the inoculation amount is 50-200 mg/L, and acetic acid is used as the denitrifying carbon source for domestication.

The beneficial effects of the present utility model are:

(1) the novel P-MFC constructed by the present utility model can realize the simultaneous removal of carbon and nitrogen, and the cathode utilizes nitrate as an electron acceptor, utilizes denitrifying bacteria to complete the reduction reaction, can treat the lower wastewater of COD concentration, and can also reduce Operating costs required for cathode aeration.

(2) There is a height difference between the anode chamber, the external aerobic reactor and the cathode chamber of the present utility model, and the waste water can be flowed by utilizing the gravitational potential energy to achieve the effect of energy saving.

(3) The P-MFC of the present invention has no damage to the plant itself, can degrade sewage and can generate electric energy at the same time. It is of great significance to alleviate the energy crisis, and has broad application prospects in the improvement of sewage irrigation efficiency, the reuse of urban domestic sewage, and the protection of artificial wetlands and natural wetlands.

Description of drawings

The accompanying drawings, which constitute a part of the present invention, are used to provide further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a structural diagram of an apparatus of Embodiment 1. FIG. Among them, 1. External aerobic reactor, 2. Water inlet and outlet, 3. Anode chamber, 4. Graphite electrode, 5. Ion exchange membrane, 6. Cathode chamber, 7. Sewage inlet, 8. Sewage outlet.

Detailed ways

It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

As described in the background art, the contradiction between the promotion of nitrification and the inhibition of denitrification by root oxygen secretion has not been resolved, and the problem that the effect of oxygen secretion of rice on denitrification promotion cannot be maximized. Therefore, the present utility model proposes a split wetland plant-microbial fuel cell. The constructed split wetland plant-microbial fuel cell separates the plant from the anode and cathode of the cell, and separates the aerobic reaction stage from the cell reaction, avoiding the influence of oxygen on the cathode denitrification process, on the premise of ensuring a certain power generation capacity. The effect of denitrification is improved.

The technical solutions of the present utility model will be described in detail below with reference to the embodiments. In the following examples, the cation exchange membrane is an Ultrex CMI-7000 type cation exchange membrane.

Example 1:

A split-type wetland plant-microbial fuel cell coupling device, comprising: an anode chamber 3, a cathode chamber 6, and an external aerobic reactor 1, the anode chamber 3 is connected to one side of the cathode chamber 6 through a cation exchange membrane 5, so the The anode chamber 3 is provided with a water inlet 7 and a water outlet 2, the water outlet 2 is connected with the water inlet of the external aerobic reactor, and the water outlet 2 of the external aerobic reactor is connected with the water inlet of the cathode chamber, so the The cathode chamber is also provided with a water outlet 8 , the anode chamber 3 and the cathode chamber 6 are both provided with graphite electrodes 4 , and a load resistance is provided between the two electrodes 4 .

Among them, the utility model is equipped with two right-angle plexiglass frames with different heights as the anode chamber and the cathode chamber, and the internal dimensions are 14 × 12 × 35 and 14 × 12 × 15 cm in turn; the external aerobic reactor consists of a tubular fixed bed. The reactor consists of internal dimensions of 28 x 12 x 30 cm. The electrode chambers and external aerobic reactors were filled with granular graphite from 2 to 6 mm in diameter as electrodes, and external connections were ensured by placing a graphite rod in each electrode chamber. A rubber sheet is inserted between each two chambers to ensure a seal.

The anode chamber is inoculated with the anaerobic digestion sludge of the urban domestic sewage treatment plant, and the inoculation amount is 100mg/L;

The cathode chamber was inoculated with the return sludge from the secondary sedimentation tank of the urban domestic sewage treatment plant, and the inoculation amount was 100 mg/L, and acetic acid was used as the denitrifying carbon source for domestication.

The wetland plants in the external aerobic reactor were reeds, and the hydraulic load of the wetland was 50-80 L/(m ² ·d).

The operation mode of the utility model for treating wastewater is that the wastewater is transported by the water pump and firstly enters the anode of the microbial fuel cell through the water inlet 7, where the organic matter is oxidized, and electrons are collected through the anode electrode. Then, the wastewater is transported to the aerobic reactor of the external plant complex for the aerobic nitrification stage due to the height difference. The wastewater is eventually transferred to the cathode where nitrate reduction occurs. Electrons generated at the anode are transferred to the cathode through an external resistor, while protons diffuse to the cathode through a cation exchange membrane (CEM).

The test results show that when rural or urban domestic sewage is used as wastewater with low carbon to nitrogen ratio, when the COD concentration in the wastewater reaches more than 200mg/l, the COD removal rate can reach 95%, and the power density can reach 85±7mw/m ² .

Example 2:

A split-type wetland plant-microbial fuel cell coupling device, comprising: an anode chamber 3, a cathode chamber 6, and an external aerobic reactor 1, wherein the anode chamber 3 is connected to one side of the cathode chamber 6 through an ion exchange membrane 5, so the The anode chamber 3 is provided with a water inlet 7 and a water outlet 2, the water outlet 2 is connected with the water inlet of the external aerobic reactor, and the water outlet 2 of the external aerobic reactor is connected with the water inlet of the cathode chamber, so the The cathode chamber is also provided with a water outlet 8 , the anode chamber 3 and the cathode chamber 6 are both provided with graphite electrodes 4 , and a load resistance is provided between the two electrodes 4 .

One side of the anode chamber 3 is attached to the external aerobic reactor 1 , and the water outlet of the anode chamber 3 is higher than the water inlet of the external aerobic reactor 1 and is located on the attached side wall. The power to make the wastewater flow comes from its own gravitational potential energy when it is transferred between the electrode chamber and the aerobic reactor, which can greatly reduce the consumption of energy and achieve the effect of energy saving.

Example 3:

A split-type wetland plant-microbial fuel cell coupling device, comprising: an anode chamber 3, a cathode chamber 6, and an external aerobic reactor 1, wherein the anode chamber 3 is connected to one side of the cathode chamber 6 through an ion exchange membrane 5, so the The anode chamber 3 is provided with a water inlet 7 and a water outlet 2, the water outlet 2 is connected with the water inlet of the external aerobic reactor, and the water outlet 2 of the external aerobic reactor is connected with the water inlet of the cathode chamber, so the The cathode chamber is also provided with a water outlet 8 , the anode chamber 3 and the cathode chamber 6 are both provided with graphite electrodes 4 , and a load resistance is provided between the two electrodes 4 .

One side of the external aerobic reactor 1 is attached to one side of the cathode chamber 6 , and the water outlet of the external aerobic reactor 1 is higher than the water inlet of the cathode chamber 6 and is located on the attached side wall. Utilize the height difference between the two to make wastewater flow, reduce energy consumption, and reduce unnecessary pipeline connections.

Example 4:

A split-type wetland plant-microbial fuel cell coupling device, comprising: an anode chamber 3, a cathode chamber 6, and an external aerobic reactor 1, wherein the anode chamber 3 is connected to one side of the cathode chamber 6 through an ion exchange membrane 5, so the The anode chamber 3 is provided with a water inlet 7 and a water outlet 2, the water outlet 2 is connected with the water inlet of the external aerobic reactor, and the water outlet 2 of the external aerobic reactor is connected with the water inlet of the cathode chamber, so the The cathode chamber is also provided with a water outlet 8, the anode chamber 3 and the cathode chamber 6 are both provided with graphite electrodes 4, and the two electrodes 4 are connected.

A resistor is provided between the electrodes 4 . The resistance can effectively limit and adjust the current size, and when the instantaneous current is too large, the short circuit phenomenon can be avoided.

Finally, it should be noted that the above are only the 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 will , it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements to some of them. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not intended to limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solutions of the present invention, those skilled in the art do not need to Various modifications or deformations that can be made with creative work are still within the protection scope of the present invention.

Claims (5)

1. a split type wetland plant-microbial fuel cell coupling device, is characterized in that, comprises: anode compartment, cathode compartment, external aerobic reactor, described anode compartment is connected with one side of cathode compartment by ion exchange membrane, so The anode chamber is provided with a water inlet and a water outlet, the water outlet is connected with the water inlet of the external aerobic reactor, the water outlet of the external aerobic reactor is connected with the water inlet of the cathode chamber, and the cathode chamber is also provided with There is a water outlet, and both the anode chamber and the cathode chamber are provided with graphite electrodes, and the two electrodes are connected. 2. The split-type wetland plant-microbial fuel cell coupling device according to claim 1, wherein one side of the anode chamber is fitted with the external aerobic reactor, and the water outlet of the anode chamber is higher than the external aerobic reactor. The oxygen reactor water inlet is located on the fitted side wall. 3. The split-type wetland plant-microbial fuel cell coupling device according to claim 1, wherein one side of the external aerobic reactor is attached to one side of the cathode chamber, and the outlet of the external aerobic reactor is in contact with one side of the cathode chamber. The water port is higher than the water inlet of the cathode chamber and is located on the fitted side wall. 4 . The split-type wetland plant-microbial fuel cell coupling device according to claim 1 , wherein a resistance is provided between the electrodes. 5 . 5. The split-type wetland plant-microbial fuel cell coupling device according to claim 1, wherein the external aerobic reactor is a wet plant.

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