CN114314808A

CN114314808A - Microbial fuel cell coupled completely autotrophic dynamic membrane reactor denitrification device and method

Info

Publication number: CN114314808A
Application number: CN202111545471.7A
Authority: CN
Inventors: 司光超; 魏东; 闫涛; 赵传富
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2021-12-16
Filing date: 2021-12-16
Publication date: 2022-04-12

Abstract

The invention discloses a denitrification device and a denitrification method for a Microbial Fuel Cell (MFC) coupled fully autotrophic dynamic membrane reactor, and belongs to the technical field of biological sewage treatment. The device comprises an MFC component, a whole autotrophic biofilm reactor, an aeration control system and a dynamic membrane separation component, wherein the MFC component is used for inlet water decarbonization pretreatment and power generation, the whole autotrophic biofilm reactor realizes high-efficiency treatment of total nitrogen, and the dynamic membrane separation component realizes sludge-water separation. The method comprises the steps of finally realizing the synergistic effect of the electrogenesis bacteria, the ammonia oxidizing bacteria and the anaerobic ammonia oxidizing bacteria to realize the high-efficiency water treatment through wastewater flow direction control, system parameter control and water quality parameter control. The invention integrates the advantages of MFC, whole-process autotrophic treatment and membrane bioreactor, has the advantages of aeration quantity saving, low sludge yield, strong load resistance and the like, realizes the electrochemical recovery of carbon source, and is particularly suitable for treating high ammonia nitrogen industrial wastewater with low carbon-nitrogen ratio.

Description

Microbial fuel cell coupled completely autotrophic dynamic membrane reactor denitrification device and method

Technical Field

The invention belongs to the technical field of biological sewage treatment, and particularly relates to a denitrification device and method of a microbial fuel cell coupled completely autotrophic dynamic membrane reactor.

Background

At present, the traditional biological nitrification and denitrification methods have many problems of long process flow, large power energy consumption, high capital investment and the like. The completely autotrophic nitrogen removal process based on integrated anaerobic ammonia oxidation is a novel autotrophic nitrogen removal process which is widely concerned in recent years, and has the advantages of saving energy, reducing sludge yield, reducing operation cost and the like. The key point for realizing the completely autotrophic nitrogen removal process is the synergistic effect of Ammonia Oxidizing Bacteria (AOB) and anaerobic ammonia oxidizing bacteria (AnAOB), but the anaerobic ammonia oxidizing bacteria belong to the autotrophic anaerobes, the growth rate is slow, the multiplication time is long, and the growth efficiency of the anaerobic ammonia oxidizing bacteria is influenced by an organic carbon source in the inlet water.

Microbial Fuel Cells (MFCs) are an advanced technology for carbon recovery, convert chemical energy into electrical energy by means of electron transfer, and can simultaneously address energy and environmental issues. The basic action principle of the MFC is that oxidation reaction such as oxidation of organic matters into carbon dioxide and water occurs at the anode, electrons are released to the cathode through an external circuit to perform reduction reaction such as reduction of oxygen into water, and current is formed to generate electricity, so that the MFC has unique advantages in the aspect of treating organic matters in organic wastewater difficult to degrade. In addition, aiming at the loss problem of anaerobic ammonium oxidation bacteria, a Membrane Bioreactor (MBR) is adopted in the prior patents and reports to replace a secondary sedimentation tank in the traditional activated sludge process so as to improve the bacteria interception efficiency and the sludge-water separation problem, and the anaerobic ammonium oxidation bacteria has the advantages of good effluent quality, small occupied area, low sludge yield and the like. But the largest application bottleneck of MBRs is cost and membrane fouling issues. As a novel MBR treatment process, a Dynamic Membrane Bioreactor (DMBR) organically combines membrane separation and biological treatment technologies, has cheap and easily-obtained base materials, can greatly reduce the manufacturing cost of the traditional MBR process, has small filtration resistance, and can automatically flow out water under the drive of water level difference as low as several millimeters. The pollution of the dynamic membrane is easy to control, and the flux of the dynamic membrane can be completely recovered by adopting an aeration mode below the membrane.

The invention aims to provide a denitrification device and a denitrification method for a microbial fuel cell coupled completely autotrophic dynamic membrane reactor. The water is pretreated by the pre-MFC to remove organic pollutants in the water body, the inhibition on the whole-course autotrophic nitrogen removal reaction is reduced, the further interception of microorganisms is realized by dynamic membrane filtration, the microbial biomass flowing out along with the effluent is greatly reduced, and the membrane pollution is reduced; the aeration quantity and the sludge surplus are reduced through the whole-process autotrophic process, the treatment cost is reduced, and the method is particularly suitable for treating high ammonia nitrogen industrial wastewater with low carbon-nitrogen ratio.

Disclosure of Invention

The invention provides a denitrification device and a denitrification method for a microbial fuel cell coupled completely autotrophic dynamic membrane reactor.

The denitrification device of the microbial fuel cell coupled completely autotrophic dynamic membrane reactor is characterized in that the MFC component and the dynamic membrane component are both positioned below the liquid level, and the MFC component is connected with an external resistor through an external titanium wire and forms a current loop with the dynamic membrane component.

The denitrification method of the microbial fuel cell coupled completely autotrophic dynamic membrane reactor is characterized by comprising the following steps:

1) wastewater enters the MFC assembly through the anode water inlet of the MFC by the water inlet pump, then enters the main denitrification reactor of the completely autotrophic biological membrane through the anode water outlet, and finally effluent is pumped out by the water outlet pump through the cathode water outlet of the dynamic membrane assembly;

2) the main denitrification reactor of the completely autotrophic biomembrane controls the dissolved oxygen to be 0.5-1.5 mg/L through an aeration pump and an aeration head, the sludge concentration (MLSS) to be 5-10 g/L, the adding amount of the suspended filler to be 30-60 percent and the hydraulic retention time to be 8-24 hours;

3) COD concentration of inlet water of the reactor is 100-600 mg/L, NH₄ ⁺The concentration of-N is controlled to be 50-400 mg/L, the ammonia nitrogen removal rate stably reaches more than 90%, the total nitrogen removal rate reaches more than 85%,the removal rate of COD is more than 90%.

The advantages and features embodied by the invention are:

(1) the MFC anode assembly is adopted to pretreat the inlet water, so that organic matters in the wastewater are removed, the inhibition of the inlet water on autotrophic reaction is slowed down, the power generation current enables energy to be recovered, the power generation efficiency is high, certain stability is achieved, the MFC anode assembly is wide in related field, and the MFC anode assembly can be used in combination with other reactors and is good in compatibility.

(2) The main denitrification adopts a whole-process autotrophic process, and is realized in one reactor, the denitrification way is simple, the operation cost is reduced, compared with denitrification, organic carbon sources are saved, and the yield of residual sludge is reduced;

(3) the stainless steel wire mesh is used as a dynamic membrane filtration substrate, so that the dynamic membrane filtration device has the advantage of low filtration resistance, can reduce the times of replacing the filtration membrane due to membrane pollution, and reduces the treatment cost.

Drawings

FIG. 1 is a schematic diagram of a carbon removal coupled whole autotrophic membrane biological device with pre-MFC and its application. In the figure: MFC component (1), a main denitrification reactor (2) with completely autotrophic biomembrane and dynamic membrane component (3), an anode water inlet (4), a carbon felt electrode (5), electrogenic bacteria (6), an ion exchange membrane (7), an anode water outlet (8), an aeration pump (9), an aeration head (10), a suspended filler (11), a magnetic stirrer (12), a heating rod (13), a stainless steel wire mesh (14), a cathode water outlet (15), a pressure gauge (16), a water outlet pump (17), titanium wires (18), an external resistor (19) and a water inlet pump (20)

Detailed Description

The present invention will be described below with reference to the drawings and examples, but the present invention is not limited to the following examples.

A continuous flow MFC coupling completely autotrophic dynamic membrane reactor is adopted to start and operate a high ammonia nitrogen wastewater treatment process, as shown in figure 1, a reactor device comprises an MFC component (1), a completely autotrophic biological membrane denitrification main body reactor (2) and a dynamic membrane component (3). Wherein the simulated wastewater enters the MFC assembly (1) through the water inlet pump (20). The MFC component is formed by cutting and assembling an organic glass plate, the length, the width and the height are 5cm, 3cm, a built-in carbon felt electrode (5), the length, the width and the thickness are 3, 0.1cm, and MFC anode inoculationThe electricity-producing bacteria are domesticated for a long time by a double-chamber MFC with 1g of sodium acetate as a substrate, and the electricity production in the domestication period is up to 0.5V. After organic matter oxidation removal in the MFC assembly is completed, the wastewater enters the main denitrification reactor (2) of the completely autotrophic biomembrane through the anode water outlet (8). The main denitrification reactor of the completely autotrophic biomembrane adopts a cylindrical structure and is made of organic glass, the inner diameter of the main denitrification reactor is 12cm, the total height of the main denitrification reactor is 40cm, the effective height of the main denitrification reactor is 32cm, and the height-diameter ratio of the main denitrification reactor to the total height of the main denitrification reactor is 2.7: 1. Dissolved oxygen is controlled to be 1mg/L through an aeration pump (9) and an aeration head (10), and a magnetic stirrer (12) realizes uniform fluidization of liquid through magnetic stirring. The suspended filler is K3 filler, belongs to plastic cylindrical material, has a diameter of 30mm and an effective surface area of 800m²/m³The amount of the catalyst added accounts for 40% of the effective volume of the reactor. The wastewater realizes high-efficiency denitrification in the main reactor. Finally, the water outlet pump (17) provides power to pump the wastewater out through the dynamic membrane module (3). Effluent is filtered by a stainless steel wire mesh (14) with the aperture of 50 mu m, enters the dynamic membrane module (3), flows out of a cathode water outlet (15), and the change of membrane flux is monitored by a pressure gauge (16). And a titanium wire (18) with the diameter of 0.8mm is used for connecting the carbon felt electrode (5), the 1000 omega external resistor (19) and the stainless steel wire mesh (14) to form an external circuit, so as to form a current loop.

The inoculation active sludge concentration of the reactor is 3400mg/L, the active sludge is taken from a laboratory-scale high ammonia nitrogen industrial wastewater reactor, and the sludge has good nitrification performance. And a simulated wastewater acclimation reactor is adopted to promote the biofilm formation of the K3 filler. The reactor adopts simulated high ammonia nitrogen wastewater as water inlet and NH as nitrogen source₄Cl and phosphorus source adopts KH₂PO₄The carbon source adopts NaCH₃COOH, the water quality of the manual water distribution is as follows: NH (NH)₄ ⁺-N 200mg/L，COD 50mg/L，KH₂PO₄ 20mg/L，CaCl₂·2H₂O mg/L，MgSO₄·7H₂O 25mg/L，FeSO₄·7H₂O20 mg/L. The reactor was operated with continuous flow and a hydraulic retention time of 24 h.

The reactor continuously runs for 90 days, the filler film formation is realized, the sludge concentration is 5g/L, and the high-efficiency denitrification of the reactor is realized by controlling the dissolved oxygen parameter. The filler after film hanging can provide good anoxic rings for anaerobic ammonium oxidation bacteriaAnd the synergistic denitrification of the ammonia oxidizing bacteria and the anaerobic ammonia oxidizing bacteria is realized. The MFC component COD removal effect is good, the removal efficiency reaches 66 percent, and the total removal rate is about 95 percent. NH (NH)₄ ⁺-N and NO₂ ^-The effluent water with the concentration of-N is reduced to below 1mg/L, and NO₃ ^-The effluent concentration of-N is about 30mg/L, and the total nitrogen removal rate is over 85 percent. The stable electricity generating voltage of the MFC is 25mV, the coupling device improves the electricity generating performance and the carbon removing effect of the MFC, and the recovery efficiency of energy is improved.

Claims

1. The utility model provides a microbial fuel cell coupling completely autotrophic dynamic membrane reactor denitrification device and method, characterized in that denitrification device includes MFC subassembly (1), completely autotrophic biomembrane denitrogenation main part reactor (2) and dynamic membrane module (3), wherein the MFC subassembly mainly includes positive pole water inlet (4), carbon felt electrode (5), electrogenesis fungus (6), ion exchange membrane (7), positive pole delivery port (8), completely autotrophic biomembrane denitrogenation main part reactor includes aeration pump (9), aeration head (10), suspension filler (11), magnetic stirrers (12), heating rod (13), the dynamic membrane module includes stainless steel wire net (14), negative pole delivery port (15), manometer (16) and play water pump (17).

2. The denitrification unit of claim 1, wherein the MFC assembly and the dynamic membrane module are both located below the liquid level, and the MFC assembly is connected with an external resistor (19) through an external titanium wire (18) to form a current loop with the dynamic membrane module.

3. The denitrification method of the coupled completely autotrophic dynamic membrane reactor of the microbial fuel cell according to claim 1, comprising the steps of:

1) wastewater firstly enters an MFC assembly through an anode water inlet (4) of the MFC through a water inlet pump (20), then enters a main denitrification reactor (2) of the completely autotrophic biomembrane through an anode water outlet (8), and finally effluent is pumped out through a cathode water outlet (15) of a dynamic membrane assembly (3) by a water outlet pump (17);

2) the main denitrification reactor (2) of the completely autotrophic biomembrane controls the dissolved oxygen to be 0.5-1.5 mg/L through an aeration pump (9) and an aeration head (10), the sludge concentration (MLSS) to be 4-10 g/L, the adding amount of a suspended filler (11) to be 30-60 percent, and the hydraulic retention time to be 8-24 hours;

3) COD concentration of inlet water of the reactor is 100-600 mg/L, NH₄ ⁺the-N concentration is controlled to be 50-400 mg/L, the ammonia nitrogen removal rate stably reaches over 90%, the total nitrogen removal rate reaches over 85%, and the COD removal rate reaches over 90%.