CN102723517A - Microbial fuel cell with separation membrane and biological negative pole, and sewage treatment method - Google Patents

Abstract

The invention discloses a separation membrane biocathode microbial fuel cell and a sewage treatment method, belonging to the technical field of sewage treatment and resource utilization in environmental engineering. It is characterized in that the reaction pool is divided into anaerobic and aerobic areas, the anode is placed in the anaerobic area, and the electrogenic bacteria on the surface of the anode degrade organic pollutants and transfer electrons to the anode; the cathode in the form of a membrane module is wrapped with a stainless steel wire mesh frame, placed in a good In the oxygen zone, the surface of the screen is domesticated to form a film, the outer layer of the biofilm is aerobic nitrifying bacteria, and the inner layer of anaerobic denitrifying bacteria can directly obtain electrons from the anode for denitrification. Sewage flows through the anaerobic and aerobic areas in sequence, and after being filtered by the cathode of the membrane module, it enters the cavity of the membrane module and pumps out the water. The effect and benefit of the present invention are that the number of cathodes in the form of membrane modules can be adjusted, and the biocathode and membrane filtration area can be flexibly changed; and the decarbonization and nitrogen removal of sewage can be completed synchronously with low consumption and high efficiency, and the effluent water quality can be guaranteed through membrane filtration, and at the same time, pollution Extract chemical energy from substances to form electrical energy output.

Description

Separation membrane biocathode microbial fuel cell and sewage treatment method

technical field

The invention belongs to the technical field of environmental engineering, and relates to sewage treatment and reclaimed water reuse technology, in particular to a sewage treatment method for synchronous decarbonization and denitrification using a biocathode microbial fuel cell to generate electricity and completing membrane filtration.

Background technique

As the world's population and economies continue to grow, so do the environmental concerns posed by energy use. Developing new types of energy characterized by low-carbon energy and gradually replacing traditional energy sources is an important way to solve the problems of fossil energy shortage and environmental pollution. Biomass energy is the energy form of solar energy stored in biomass in the form of chemical energy, and it is a new energy source with extensive use value. Microbial fuel cell technology regards wastewater as the carrier of energy and resources, uses organic pollutants as anode fuel, and further converts biomass energy into the cleanest energy—electric energy, so as to realize the unification of wastewater treatment and electric energy generation, which can be used in the technology Support and promote the development of "low-carbon economy".

With the improvement of people's living standards, the nitrogen content of urban sewage has increased relatively, showing the characteristics of a low carbon-to-nitrogen ratio. The microorganisms loaded on the biocathode of the microbial fuel cell can directly use the electrode as an electron donor to obtain electrons, and nitrate or nitrite As the final electron acceptor, denitrification can improve the nitrogen removal efficiency of wastewater with low carbon-to-nitrogen ratio.

Compared with non-biological cathodes, biocathodes reduce the operation and construction costs of microbial fuel cells, and microorganisms themselves participate in electron transfer as catalysts or mediators, replacing noble metal catalysis and non-recyclable electron mediators, thereby solving catalyst poisoning and oxidant Complementary problems enable microbial fuel cells to be sustainable at low cost. Clauwaert et al. studied the reduction of nitrate by biocathode for the first time, and found that biocathode can be used as an electron donor to achieve complete denitrification of nitrate and improve the operability of microbial fuel cells. Virdis et al. have studied the simultaneous denitrification and carbon removal of biocathode microbial fuel cells. At the cathode, synchronous nitrification and denitrification can be realized by adding an external nitrification reactor or online aeration to achieve the removal of nitrogen pollutants.

my country is facing the dual pressure of water shortage and serious water pollution. Reuse of reclaimed water is one of the effective means to solve this problem. Membrane bioreactor covers a small area and has good effluent quality. It is a combination of activated sludge degradation and membrane filtration. An integrated high-efficiency sewage recycling technology, but membrane fouling and high membrane costs limit its application and development. Based on low-cost support materials, the concept of dynamic membranes on which biofilms are formed for filtration can greatly reduce the cost of membrane modules. The organic combination of microbial fuel cells and membrane bioreactors for low carbon-to-nitrogen ratio sewage treatment can further reduce the operating cost of water treatment technology on the premise of ensuring the quality of effluent water.

Contents of the invention

The purpose of the present invention is to provide a microbial fuel cell electric energy output, while completing the carbon and nitrogen pollution removal and membrane filtration sewage recycling method, the separation membrane bio-cathode microbial fuel cell designed and constructed by this method can not only obtain higher electric energy output, and at the same time of biological cathode nitrification and denitrification, membrane filtration can be completed, which is conducive to promoting energy saving and consumption reduction of water pollution control technology and realizing sustainable development.

For above-mentioned purpose of the invention, the solution that the present invention adopts is:

A separation membrane biological cathode microbial fuel cell, which is divided into anaerobic zone and aerobic zone, the anode is placed in the anaerobic zone, the cathode in the form of a membrane module is placed in the aerobic zone, and an aeration head is arranged under the membrane module in the aerobic zone; anaerobic zone The aerobic zone and the aerobic zone are separated by a partition, and the partition controls the liquid level of the anaerobic zone at the same time. The cathode in the form of a membrane module wraps the frame with a conductive metal mesh, and a biofilm is attached to the surface of the metal mesh. The metal grid is connected with external wires. The number of cathodes in the form of membrane modules can be adjusted to change the area of biological cathodes and membrane filtration.

A sewage treatment method using a separation membrane biocathode microbial fuel cell comprises the following steps:

(1) The reactor is inoculated with activated sludge, the anode domesticates the electrogenic bacteria, degrades the pollutants and generates electrons; the cathode surface domesticates the biofilm, the outer layer is aerobic nitrifying bacteria, and the ammonia nitrogen nitrification is completed, and the inner layer is anaerobic denitrifying bacteria, The electrons transferred from the anode are directly obtained from the electrode for denitrification; the amount of electricity produced is used as an indicator of domestication and maturity, and is monitored with a voltmeter.

(2) Sewage flows through the anaerobic zone and the aerobic zone sequentially. The electrogenic bacteria are attached to the surface of the anode in the anaerobic zone, and the organic or inorganic substances in the wastewater are used as the anode fuel, and the preliminary utilization and degradation are carried out in the anode area, and the waste water is extracted to contain Biomass produces protons and electrons simultaneously. Electrons are transferred to the cathode through an external circuit and load, and cations such as protons move to the cathode inside the battery to participate in the reaction. The residual organic matter and ammonia nitrogen from electricity production in the anaerobic zone enter the aerobic zone. The removal of organic carbon and ammonia nitrogen nitrification are completed in the aerobic zone and the surface of the cathode biofilm, and the denitrification and denitrification are completed in the inner layer of the biofilm on the cathode surface. After filtration, it enters the cavity of the membrane module, pumps out water, completes simultaneous decarbonization and nitrogen removal and filtration, and extracts chemical energy to form electrical energy output.

Effects and benefits of the present invention are

(1) The present invention is equipped with several cathodes in the form of membrane modules, which increases the cathode area and membrane filtration area of the microbial fuel cell, and is easy to replace, maintain and adjust; wastewater can realize nitrification and cathode autotrophic denitrification in the cathode area, realizing The removal of nitrogen pollutants; the dynamic membrane with metal mesh as the skeleton filters the effluent, which ensures the quality of the effluent and reduces the cost of membrane production; extracts chemical energy from pollutants to form electrical energy output, further reducing operating costs.

(2) The separation membrane biocathode microbial fuel cell occupies a small area and is easy to operate. It is suitable for modular and integrated reactor design, and has broad application prospects in the fields of sewage treatment and reclaimed water reuse, such as: no drainage pipe Network system areas, such as resorts and tourist attractions; areas or places that require reuse of reclaimed water, such as hotels and car washes; renewal and upgrading of existing urban sewage treatment plants, etc.

Description of drawings

The accompanying drawing is a schematic diagram of a separation membrane biocathode microbial fuel cell.

In the figure: 1 water inlet; 2 anode; 3 anaerobic zone; 4 outlet of membrane module; 5 membrane module; 6 aeration head; 7 external wire; 8 frame; 9 metal mesh; 10 aerobic zone.

Detailed ways

The specific embodiments of the present invention will be described in detail below in conjunction with the technical solutions and accompanying drawings.

Example

The amount of treated domestic sewage is calculated as 600m ³ /d, the concentration of COD is 200mg/L, and the concentration of TN is 50mg/L. The anaerobic zone 3HRT of the separation membrane biocathode microbial fuel cell is designed to be 4h, and the aerobic zone 10HRT is 4h. The total effective volume of the reactor is 200m ³ , the size of the anaerobic zone 3 and the aerobic zone 10 are both 5m×10m, the height is 4m, and the height is 0.5m. The filtration flux of the cathode membrane module 5 is designed to be 100L/h·m ² , and 10 membrane modules with a membrane size of 3 m×4 m are required. The membrane module 5 is hollow inside and is composed of a metal mesh 9 wrapped around a frame 8, and the pore size of the metal mesh 9 is 1000 mesh. left and right, which is conducive to film formation and ensures the quality of effluent water. The metal net is connected with external electric wire 7.

The reactor is inoculated with activated sludge; the surface of the anode 3 domesticates the electrogenic bacteria, degrades the pollutants and generates electrons; the surface of the cathode membrane module 5 domesticates the biofilm, the outer layer is aerobic nitrifying bacteria, and the ammonia nitrogen nitrification is completed, and the inner layer is anaerobic denitrification The bacteria directly obtain the electrons transferred from the anode from the electrode for denitrification.

Sewage flows through the anaerobic zone 3 and the aerobic zone 10 in sequence, and the residual organic matter and ammonia nitrogen generated in the anaerobic zone 3 enter the aerobic zone 10, and the removal of organic carbon and ammonia nitrogen are completed in the aerobic zone 10 and the biofilm surface of the cathode membrane module 5 Nitrification, denitrification and denitrification are completed in the inner layer of the biofilm of the cathode membrane module 5, and after being filtered by the cathode membrane module, it enters the cavity of the membrane module 5, pumps out water, completes simultaneous decarbonization and nitrogen removal and filtration, and extracts chemical energy to form power output.

Claims (3)

1. a separation membrane bio-cathode microbial fuel cell is characterized in that: this separation membrane bio-cathode microbial fuel cell is divided into anaerobic zone (3) and aerobic zone (10), and anode is placed in anaerobic zone, membrane assembly ( 5) Form the cathode is placed in the aerobic zone, and the aeration head (6) is arranged under the membrane module (5) of the aerobic zone (10); the anaerobic zone (3) and the aerobic zone (10) are separated by a partition, and the partition The plate controls the liquid level in the anaerobic zone at the same time; the cathode in the form of the membrane module (5) wraps the frame (8) with a metal mesh, and a biofilm is attached to the surface of the cathode; the metal mesh is connected with an external wire. 2. A separation membrane biocathode microbial fuel cell according to claim 1, characterized in that the number of cathodes in the form of membrane modules is adjustable, and the area of biocathode and filter membrane can be changed. 3. apply the sewage treatment method of separation membrane biocathode microbial fuel cell described in claim 1 or 2, it is characterized in that comprising the steps: (1) The reactor is inoculated with activated sludge; the anode domesticates the electrogenic bacteria, degrades the pollutants and generates electrons; the cathode surface domesticates the biofilm, the outer layer is aerobic nitrifying bacteria, and the ammonia nitrogen nitrification is completed, and the inner layer is anaerobic denitrifying bacteria, The electrons transferred from the anode are directly obtained from the electrode for denitrification; the amount of electricity produced is used as an indicator of domestication and maturity, and is monitored with a voltmeter. (2) The sewage flows through the anaerobic zone and the aerobic zone sequentially. The residual organic matter and ammonia nitrogen from the anaerobic zone enter the aerobic zone. The removal of organic carbon and ammonia nitrogen nitrification are completed in the aerobic zone and the surface of the cathode biofilm. The inner layer of the biofilm completes denitrification and denitrification. After being filtered by the cathode of the membrane module, it enters the cavity of the membrane module, pumps out water, completes simultaneous decarbonization and nitrogen removal and filtration, and extracts chemical energy to form electrical energy output.