CN102351387B

CN102351387B - Artificial wetland coupling microbial fuel cell (MFC) system and method for improving removal efficiency of organic matters

Info

Publication number: CN102351387B
Application number: CN 201110274372
Authority: CN
Inventors: 宋海亮; 李先宁; 吴磊; 项文力
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2011-09-16
Filing date: 2011-09-16
Publication date: 2013-05-08
Anticipated expiration: 2031-09-16
Also published as: CN102351387A

Abstract

The invention discloses a constructed wetland coupled MFC system, which is characterized in that the system is composed of constructed wetland loaded with MFC, and the system is covered with a coarse gravel layer, an activated carbon layer, an insulating gravel layer, a top conductive material layer, plants, and activated carbon from bottom to top. layer constitutes the anode of the MFC, and the top conductive material layer constitutes the cathode of the MFC, and the cathode and anode electrodes are respectively led out by wires and connected to an external circuit. The invention discloses a method for improving organic matter removal efficiency by coupling artificial wetland with MFC. Constructed wetland coupled with MFC not only expands the way of organic matter degradation, greatly improves the removal efficiency of organic matter, especially refractory organic matter, but also improves the power generation performance of MFC. Crisis and an effective way to solve environmental problems, has immeasurable development potential.

Description

Artificial swamp coupling MFC system improves the method for organic matter removal usefulness

Technical field

The invention belongs to the energy and water treatment field, be specifically related to be applicable to the artificial swamp coupling MFC(Microbial Fuel Cell that sewage disposal is reclaimed electric energy and improved the organic matter removal efficiency, microbiological fuel cell) production capacity water conditioning method.

Background technology

Along with the development of economy, the energy and environmental problem become increasingly conspicuous.The report of UNEP (United Nations Environment Program) shows, the environment of the whole earth worsens comprehensively, and environmental problem is a global problem.If the energy and environmental problem can not get effective solution, not only the target of human social is difficult to realize, and the mankind's living environment and quality of life also can be had a strong impact on.Therefore, countries in the world are emphasized the relation of energy and environment more on energy strategy and policy, more note the importance of environment protection.Under this international situation, renewable energy source is subject to the attention of countries in the world with its unique advantage, the development and utilization renewable energy source oneself through becoming the important component part of the world energy sources strategy of sustainable development, become the basic selection of most of developed countries and part developing country 21 century energy development strategy.

In various renewable energy sources, biomass energy is unique, and it is not only the sun power of storage, especially unique a kind of reproducible carbon source.Biomass energy can obtain from multiple waste, can be used as a kind of mode of changing waste into resources, realizes the Sustainable development of the utilization of resources.At sewage treatment area, along with the development of biotechnology in recent years, the biological treatment of sewage not only becomes the major technique in this field, and has realized the recycling of sewage when realizing sewage disposal.

MFC is the catalytic activity of utilizing enzyme or microorganism, by its metabolism, oxidation operation is produced the device of electric energy.It belongs to the biochemical conversion technology in biomass energy utilization technologies, is electric energy with Wood Adhesives from Biomass.MFC being applied to field of waste water treatment, obtaining electric energy when processing organic waste water, is the effective way of alleviating current energy dilemma and solving environmental problem, is also one of the hot research problem in environmental energy field.

Not only nitrogen, phosphorus removal ability are by force, the Construction and operation cost is low, management maintenance convenient for artificial swamp, and have advantages such as the high-specific surface area of internal medium that aerobic/anaerobic has both, matrix, long hydraulic detention time and plant rhizosphere effect, make artificial swamp have higher potential to the removal of organism especially hardly degraded organic substance, also be subject to extensive concern.Adria(Ah Baudrillard) etc. the people proves that trichlorobenzene is converted into monochloro benzene by the reductive action dechlorination of microorganism.The process of microbiological deterioration Perchlorobenzene tetrachloroethylene or polychlorobiphenyl is by the reductive dehalogenation effect, the product that obtains, more further degrade by the biodegradation process under aerobic condition.

The advantage of comprehensive MFC and artificial swamp, introduce the MFC technology in artificial swamp, with the high-specific surface area matrix of artificial swamp lower floor anaerobic environment through after modification as the anode of MFC, with the top layer matrix of the artificial swamp air cathode as MFC, build artificial swamp-MFC, by kind in wet land system and the abundant microorganism of quantity, form electrode-microorganism biological pole effect, the plant-microorganism rhizosphere effect, matrix-microbial biofilm effect, and pass through the degraded that the electrogenesis microorganism promotes various pollution substances, collect simultaneously the electric energy that produces.Artificial swamp coupling MFC method, biological renovation method as a kind of complex function, not only has its unique ecosystem, can multipath ground purifying contaminated material, promote the especially degraded of Persistent organic pollutants of organism, and can reclaim the electric energy that produces, and realizing the recycling of the energy and the maximum using of resource, its research has the realistic meaning of highly significant.

The research that present MFC is applied in artificial swamp there is not yet report both at home and abroad.

Summary of the invention

The object of the present invention is to provide a kind of artificial swamp coupling microorganism fuel to improve the method for organic matter removal usefulness.

In order to realize the foregoing invention purpose, the present invention adopts following technical scheme:

A kind of artificial swamp coupling MFC improves the method for organic matter removal usefulness, it is characterized in that, at first, waste water enters artificial swamp through inhalant region, after the bottom even water distribution, be pulling flow type along the rough sand gravel bed and rise, wherein organism adsorbs, holds back, decomposes by preliminary degraded because of the microbial film that a large amount of microorganism growth in rough sand gravel surface form; Then, the waste water of preliminary degraded enters active carbon layer, this layer is in strict anaerobic environment, and has a high surface area, by the adsorption of gac self and the anaerobic digestion process of upper attached microbial thereof, organism is removed, and facilitated the generation of electric current by the activity of electrogenesis bacterium, promoted the especially degraded of hardly degraded organic substance of organism; Then, wastewater streams is through insulation grit layer, and this layer is the anaerobic and aerobic zone of transition, and the residual contamination thing is by the absorption of the microbial film of fine sand gravel surface attachment, degraded; At last, waste water flows into the top layer conductive material layer, this layer part is immersed in water, a part is exposed in air, planting plants therebetween, in air, the dissolving of oxygen and root system of plant discharge to the transmission of oxygen that to make this layer be aerobic zone, and residual contamination thing further absorption, the rhizosphere effect of propagation, alienation and the plant by microorganism is removed; Active carbon layer consists of the anode of MFC simultaneously, the top layer conductive material layer consists of the negative electrode of MFC, the electrogenesis bacterium degradation of organic substances of anode enrichment produces proton and electronics, electronics is exported outside the electrogenesis mycetocyte, be directed at negative electrode through electrode and external circuits, proton with solution upper reaches in reactor to negative electrode, in the presence of oxygen, the generating electrodes water generation reaction has been completed the whole process of electrogenesis function.

The present invention's MFC technology that is coupled in artificial swamp, with the high-specific surface area matrix of artificial swamp lower floor anaerobic environment through after modification as the anode of MFC, with the top layer matrix of the artificial swamp air cathode as MFC, build single chamber without film MFC type artificial swamp, combine the performance advantage of MFC and artificial swamp.On the one hand, the enabling environment of MFC anode provides the groundwork environment for the removal of organism especially hardly degraded organic substance.Simultaneously, utilize the electronics circulation of MFC internal system, strengthened the supply of organism electronics, promoted organic degraded.On the other hand, root system of plant and stromal surface enriched microorganism, and biofilm growth formation are strengthened the adsorption-decomposition function water pollutant, and the micromolecular compound of root system secretion and enzyme help to have improved microorganism active, further promote the degraded of pollutent.Whole system has not only been expanded the approach of organic matter degradation; increased substantially the especially removal usefulness of refractory organic of organism; improved simultaneously the electricity generation performance of MFC; obtained electric energy when promoting wastewater degradation; be the effective way of alleviating current energy dilemma and solving environmental problem, have immeasurable development potentiality.

Description of drawings

Fig. 1 is the structural representation of the artificial wetland coupling of the present invention MFC system.Wherein, 1-inhalant region; 2-rough sand gravel bed; The 3-active carbon layer; 4-insulation grit layer; 5-top layer conductive material layer; The 6-plant; The 7-root system of plant; The 8-external circuits; The load of 9-external circuits; The 10-exhalant region.

Fig. 2 is the practical application concept map of the artificial wetland coupling of the present invention MFC system.Wherein, 1-inhalant region; 2-rough sand gravel bed; The 3-active carbon layer; 4-insulation grit layer; 5-top layer conductive material layer; The 6-plant; The 7-root system of plant; The 8-external circuits; The load of 9-external circuits; The 10-exhalant region.

Embodiment

As depicted in figs. 1 and 2, artificial swamp coupling MFC system loads MFC by artificial swamp and consists of, system is furnished with rough sand gravel bed, active carbon layer, insulation grit layer, top layer conductive material layer and plant from bottom to top, active carbon layer consists of the anode of MFC, the top layer conductive material layer consists of the negative electrode of MFC, and the cathode and anode electrode is derived by wire respectively and is connected with external circuits.Artificial swamp coupling MFC can improve organic matter removal usefulness in waste water greatly, method and process are as follows: at first, waste water enters artificial swamp through inhalant region, after the bottom even water distribution, be pulling flow type along the rough sand gravel bed and rise, wherein organism adsorbs, holds back, decomposes by preliminary degraded because of the microbial film that a large amount of microorganism growth in rough sand gravel surface form; Then, the waste water of preliminary degraded enters active carbon layer, this layer is in strict anaerobic environment, and has a high surface area, by the adsorption of gac self and the anaerobic digestion process of upper attached microbial thereof, organism is removed, and facilitated the generation of electric current by the activity of electrogenesis bacterium, promoted the especially degraded of hardly degraded organic substance of organism; Then, wastewater streams is through insulation grit layer, and this layer is the anaerobic and aerobic zone of transition, and the residual contamination thing is by the absorption of the microbial film of fine sand gravel surface attachment, degraded; Last waste water flows into the top layer conductive material layer, this layer part is immersed in water, a part is exposed in air, planting plants therebetween, in air, the dissolving of oxygen and root system of plant discharge to the transmission of oxygen that to make this layer be aerobic zone, and residual contamination thing further absorption, the rhizosphere effect of propagation, alienation and the plant by microorganism is removed.In said process, active carbon layer with conductive characteristic has consisted of the anode of MFC, the top layer conductive material layer has consisted of the negative electrode of MFC, and the cathode and anode electrode is derived by wire respectively and is connected with external circuits, and the electrogenesis bacterium degradation of organic substances of anode enrichment produces proton and electronics, electronics is exported outside the electrogenesis mycetocyte, be directed at negative electrode through electrode and external circuits, proton with solution upper reaches in reactor to negative electrode, in the presence of oxygen, the generating electrodes water generation reaction has been completed the whole process of electrogenesis function.

For purification efficiency and the electrogenesis usefulness of further raising system, wherein, it is the activated carbon granule of 3-5mm that active carbon layer can adopt diameter, and tamped density is 0.45-0.55g/cm ³It is the ganoid sandstone material of 6-8mm that the grit of insulation grit layer can be selected diameter, avoiding increasing flow resistance, and affect proton transfer, and then the internal resistance of increase MFC system; The electro-conductive material of top layer conductive material layer can adopt granulated active carbon, stainless steel, carbon cloth, graphite granule or graphite felt etc., and can carry out catalytic treatment; Wire preferably adopts the titanium wire, also can adopt copper conductor, and carries out the insulated enclosure processing of tie point, to avoid solution to the corrosion of wire; Plant root preferably can penetrate the anode layer district, i.e. the active carbon layer district.

the production capacity type artificial swamp coupling MFC water conditioning technical operation principle of the present embodiment is such, pollutant effluents is entered by the bottom, after uniformly distributing along rough sand gravel bed rising, the anode active carbon layer by matrix with and on the microbial film that adheres to pollutent is adsorbed, purify, electronics and proton have been produced in degradation process, electronics is through anode, external circuit arrives negative electrode, and proton arrives negative electrode through upper portion insulating grit layer, negative electrode with oxygen as electron acceptor(EA), with proton and oxygen generating electrodes water generation reaction, form loop and generation current, in the loop, the supply of organism electronics has been strengthened in the generation of electric current, promoted organic degraded.Simultaneously wetland plant utilizes the plant rhizosphere effect, to the pollutent in wetland remove, conversion and fixing, the enzyme of plant root secretion has also promoted the degraded of pollutent.The simple compounds such as acetate of root hair cell secretion, and the micromolecular compound after the rhizospheric microorganism degradation of contaminant in addition more easily absorb and degraded for the electrogenesis bacterium, thereby can improve the biological activity of electrogenesis bacterium.The collaborative coupling of whole system has been strengthened the material and energy flow in the system logical, has promoted its purification efficiency, has also strengthened production capacity usefulness.

Claims

1. A method for constructing wetland coupled with MFC to improve the efficiency of organic matter removal, characterized in that, at first, the waste water enters the constructed wetland through the water intake area, and after the water is evenly distributed from the bottom, it rises in push flow along the coarse gravel layer, wherein the organic matter is due to The biofilm formed by the growth of a large number of microorganisms on the surface of coarse gravel is initially degraded by adsorption, retention, and decomposition; then, the initially degraded wastewater enters the activated carbon layer, which is in a strict anaerobic environment and has a high surface area. Adsorption and the anaerobic digestion process of attached microorganisms remove organic matter, and promote the generation of electric current through the activity of electrogenic bacteria, which promotes the degradation of organic matter, especially refractory organic matter; then, the wastewater flows through the insulating gravel layer, This layer is an anaerobic and aerobic transition zone, and the remaining pollutants are adsorbed and degraded by the biofilm attached to the surface of the fine gravel; finally, the wastewater flows into the top conductive material layer, which is partly submerged in water and partly exposed to the air. Plants, the dissolution of oxygen in the air and the transfer and release of oxygen by plant roots make this layer an aerobic area, and the remaining pollutants are further removed through microbial proliferation, dissimilation, plant absorption, and rhizosphere effect; at the same time, the activated carbon layer constitutes the MFC. The anode and the top conductive material layer constitute the cathode of the MFC. The electrogenic bacteria enriched at the anode degrade the organic matter to generate protons and electrons. The electrons are exported to the outside of the electrogenic bacteria and lead to the cathode through the electrodes and external circuits. The protons flow up with the solution in the reactor. To the cathode, with the participation of oxygen, an electrode reaction occurs to generate water, completing the whole process of electricity generation.

2. The method of coupling MFC with constructed wetland to improve organic matter removal efficiency according to claim 1, characterized in that the diameter of activated carbon particles in the activated carbon layer is 3-5mm, and the packing density is 0.45-0.55g/cm ³ .

3. The method of coupling constructed wetland with MFC to improve organic matter removal efficiency according to claim 1, characterized in that the sand and gravel of the insulating sand and gravel layer are sand and gravel materials with a diameter of 6-8 mm and a smooth surface.

4. The method for improving organic matter removal efficiency by coupling MFC with constructed wetland according to claim 1, characterized in that the conductive material of the top conductive material layer is granular activated carbon, stainless steel, carbon cloth, graphite particles or graphite felt.

5. The method of coupling constructed wetland with MFC to increase organic matter removal efficiency according to claim 1, characterized in that the plant roots penetrate the anode layer area. the