Aeration membrane bioreactor containing biological comfortable interface and treatment method of low-temperature domestic sewage

Abstract

The invention relates to an aeration membrane bioreactor containing a biological comfortable interface and a treatment method of low-temperature domestic sewage. The reactor comprises a biological treatment part I and a hot air generation part II, a heat flow exchange assembly in the hot air generation part II is cylindrical, round holes are uniformly distributed in the side surface of the cylinder, and a heating sheet wraps the side surface of the cylinder; the biological treatment part I depends on the MABR technology and is composed of an air inlet channel, a membrane assembly, a water storage device and an air pressure adjusting assembly, the air inlet channel is arranged in the middle, the water storage device is arranged on the outer side, and the air inlet channel and the water storage device are separated through the MABR membrane assembly. According to the invention, oxygen and heat are transferred to a biological membrane through an MABR technology to construct a biological comfortable area, the MABR technology is used as a main body, an aerobic-anoxic-anaerobic layer is provided, synchronous nitrification and denitrification are realized in a single tank body, an efficient treatment effect is realized, the aeration energy consumption is lower, the heat supply is less, the occupied area is smaller, and the treatment cost is reduced. And the method has applicability to treatment of various low-temperature water.

Description

Technical Field

[0001] The present invention relates to a method for treating low-temperature domestic sewage with low energy consumption, in particular to a "biocomfort interface" aerated membrane bioreactor (MABR) technology based on targeted heating and targeted oxygen supply. Background Art

[0003] The Chinese patent publication number CN116693057A, "Intelligent Modular Integrated Treatment Equipment for Domestic Sewage in Cold Region Highway Service Areas", introduces a domestic sewage treatment equipment in cold regions, which increases the sewage temperature by circulating water heating to ensure the sewage treatment effect. However, excessive heating not only leads to higher energy consumption, but also may affect the long-term stability of the equipment.

[0004] The Chinese patent publication number CN106219746A, "A device and method for strengthening sewage treatment by combining calcium chloride and magnetic field at low temperature", proposes to improve the treatment effect of low-temperature sewage through the synergistic effect of calcium chloride and magnetic field. Although this method can help improve treatment efficiency in some cases, it relies on the action of chemical additives and physical fields, which may cause environmental pollution and system complexity.

[0005] The Chinese patent publication number CN111453847A, "A Low-temperature Sewage Treatment System and Treatment Process", uses a multi-point water inlet method to increase the ammonia nitrogen removal rate to 67%. Although this method effectively improves the treatment effect, its adaptability to low-temperature environments is still limited, and there are problems with complex equipment and process configuration.

[0006] The Chinese patent publication number CN116693038A, "A low-carbon treatment device and method for low-temperature domestic sewage in plateau agricultural and pastoral areas", introduces adapting to low-temperature environments by inoculating cold-resistant bacteria and reducing aeration volume. However, this method requires specific strains of bacteria and has strict requirements on sewage quality, and its scope of application is limited.

[0007] Chinese patent publication number CN109205783A, "Method for simultaneous carbon removal, nitrogen removal and phosphorus removal of domestic sewage at low temperature based on A-SBR process", constructs aerobic granular sludge by adding rice husk biochar, which effectively improves the ammonia nitrogen removal rate, but still faces the problems of low energy efficiency and high treatment cost in low temperature environment.

[0008] In general, existing technologies enhance low-temperature tolerance by increasing sewage temperature, staged water inlet or modified sludge, but these methods generally have disadvantages such as high energy consumption, strong limitations or excessively high time costs, and have not yet provided an economically feasible and widely applicable low-temperature domestic sewage treatment technology. Summary of the invention

[0009] The purpose of the present invention is to solve the problems of high energy consumption and strong limitations in the treatment of low-temperature domestic sewage, and to provide an aerated membrane bioreactor with a biological comfort interface and a method for treating low-temperature domestic sewage. The present invention constructs a biological comfort zone through targeted oxygen and heat supply, uses MABR technology to directly transfer bubble-free oxygen to the biofilm, and heats the air in MABR technology, and provides the appropriate temperature air to the attached biofilm through a non-porous membrane. This targeted delivery fundamentally realizes low-energy and high-efficiency treatment of low-temperature domestic sewage, and reaches the Class A emission standard.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] An aerated membrane bioreactor with a bio-comfortable interface, the reactor comprising a biological treatment part I and a hot air generating part II;

[0012] The hot air generating part II includes an air inlet 1, an air outlet 1, a heating plate, a heat exchange component, and a hot air storage component;

[0013] The heat exchange component is cylindrical, and circular holes are evenly distributed on the side of the cylinder, and the heating plate is wrapped around the side of the cylinder; the area ratio of the front view of the heat exchange component to the front view of the hot air storage component is 26%;

[0014] The biological treatment part I relies on MABR technology and is composed of an air inlet channel, a membrane module, a water reservoir and an air pressure regulating module;

[0015] The air outlet 1 of the hot air generating part II is connected with the air inlet 2 and the air inlet passage of the biological treatment part I, and the air inlet is regulated by the air pressure regulating component;

[0016] The biological treatment part I has an air inlet channel in the middle and a water reservoir on the outside, which are separated by the MABR membrane assembly.

[0017] Furthermore, the diameter of the circular hole is 1 cm, and the center interval between the circular holes is 1.5 cm.

[0018] Furthermore, the heating plate is divided into three categories, namely: ① only electric heating: nickel-chromium alloy or copper; ② only photothermal: polypyrrole coating, graphene oxide film or copper sulfide; ③ both photothermal and electric heating: carbon felt, carbon nanotubes, MXene or graphite.

[0019] A method for treating low-temperature domestic sewage using the above-mentioned aerated membrane bioreactor containing a bio-comfort interface, the method specifically comprising:

[0020] The air in the heat exchange component is heated by the heating plate, and then the air in the hot air storage component is heated. When the predetermined temperature is reached, the air enters the air inlet channel of the biological treatment part I through the air outlet 1 and the air pressure regulating component. At the same time, low-temperature domestic sewage is introduced into the water reservoir. The hot air in the air inlet channel diffuses to the MABR membrane component, and sewage treatment is achieved through the MABR membrane component.

[0021] Furthermore, the membrane assembly adopts a non-porous silica flat membrane assembly, two non-porous silica flat membranes are placed on a support frame, and heat and air are transferred to the biofilm attached to the silica flat membrane through hot air;

[0022] If the membrane assembly uses a hollow fiber membrane, the channel inside the membrane is the air inlet channel and no support frame is required; the air pressure inside the membrane is maintained constant through the air pressure regulating assembly.

[0023] Furthermore, the reservoir adopts an intermittent flow process with a hydraulic retention time of 20 hours.

[0024] Furthermore, the temperature of the low-temperature domestic sewage is kept stable by circulating water in the water storage tank, and the low-temperature circulating water flows into the lower end of the biological treatment part and flows out from the upper end.

[0025] The beneficial effects of the present invention compared to the prior art are as follows: the low-temperature sewage treatment system of the present invention is different from the traditional surface source water heating or the domestication of a single bacterial species. The present invention uses the MABR technology to transfer oxygen and heat to the biofilm point-to-point to construct a biological comfort zone. At the same time, the MABR technology is used as the main body, and it has an aerobic-anoxic-anaerobic layer, and realizes simultaneous nitrification and denitrification in a single tank body, achieving an efficient treatment effect, with lower aeration energy consumption, less heat supply, and a smaller footprint, and is applicable to the treatment of various low-temperature waters. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It shows the different components of the reactor and the water and air flows. I is the biological treatment part, II is the hot air generating part, and the lower right corner is the front view of the hot air generating part.

[0027] Among them, 1-water inlet one, 2-water outlet one, 3-water outlet two, 4-air outlet two, 5-water inlet two, 6-air inlet two, 7-air inlet one, 8-air outlet one, 9-water flow, 10-gas flow, 11-gas flow state, 12-heating plate, 13-heat exchange component, 14-hot air storage component, 15-air pressure regulating component.

[0028] Figure 2 It is a schematic diagram of the hot air flow and low-temperature water flow of the biological component of the present invention.

[0029] Figure 3 The following is a comparison chart of two groups of intake air temperature and water temperature.

[0030] Figure 4 This is a comparison chart of the inlet and outlet concentrations of two groups of ammonia nitrogen, COD and total nitrogen.

[0031] Figure 5 This is a diagram of the reactor structure of Example 2.

[0032] Figure 6 The absorbance and microstructure of the carbon felt material used in the experiment.

[0033] Figure 7 This is a diagram of the light intensity during the day.

[0034] Figure 8 Figure 2 is a graph of ambient temperature and material temperature.

[0035] Fig. 9 This is a temperature change graph.

[0036] Fig.10 This is a diagram of the ammonia nitrogen removal effect. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0038] Embodiment 1:

[0039] I is the biological treatment part, the outer layer is a water reservoir, which is a low-temperature domestic sewage area, and the inner layer is a non-porous silica flat membrane component and an air chamber.

[0040] The water enters from the water inlet 1 and flows out from the water outlet 2; the circulation part flows in from the circulation water inlet 25 at the lower end of the component and flows out from the circulation water outlet 23 at the top of the component. The water temperature is kept stable by the counter-gravity water flow 9; the gas enters from the air inlet 26 at the upper end of the MABR membrane component and flows out from the air outlet 24. The gas flow is as shown in 10. The gas flow 10 and the water flow 9 are in opposite directions, which is conducive to the molecular oxygen carrying heat to the attached biofilm. The membrane component adopts a PDMS non-porous membrane with a thickness of 100μm. While ensuring effective oxygen transfer, it prevents water vapor from entering the air cavity, effectively avoiding membrane pollution and ensuring long-term operation. The dissolved oxygen in the water is controlled at 0-0.4mg / L to ensure the formation of the aerobic-anoxic-anaerobic layer of the biofilm and realize simultaneous nitrification and denitrification.

[0041] II is the hot air generating part, 12 is the heating plate (made of nickel-chromium alloy or copper), 13 is the heat exchange component, 14 is the hot air storage component, the heating plate 12 is rectangular, covered on the heat exchange component for fixing, with a coverage rate of 60%; the heat exchange component 13 is cylindrical, with circular holes evenly distributed on it for heat transfer, the diameter of the circular holes is 1 cm, and the center interval between the circular holes is 1.5 cm. The upper side of the cylinder of the heat exchange component 13 coincides with the hot air storage component 14, and the lower bottom surface can be open or sealed. The area ratio of the heat exchange component 13 to the hot air storage component 14 in the front view is 26%, 15 is the air pressure regulating component, after the gas enters the system from the air inlet 7, it first enters the cylinder of the heat exchange component 13, and the heating plate 12 is powered for the first heating, and then the heat enters the hot air storage component 14 through the circular holes on the side of the heat exchange component 13. After sufficient heating, it flows out from the air outlet 8 and enters the biological treatment part, and the air pressure is controlled by the air pressure regulating component 15. 11 is the gas flow state.

[0042] The hot air generating device simulates the formation of hot air in a factory. A rectangular heating plate 12 wraps a cylinder, and the cylinder is placed in a rectangular acrylic component. The air inlet is set above the rectangular body, and the air outlet is set below the cylinder to fully heat the air.

[0043] In order to explore the effect of the "bio-comfortable interface" reactor, a control group was set up for effect comparison. Group A was the experimental group and Group B was the control group. Figure 3 As shown, the domestic sewage of the two groups was fixed at about 11.5±0.15℃, the intake air temperature of group B was controlled at 11.6±0.21℃, and the intake air temperature of group A was controlled at 31±0.4℃, and the rest of the settings were the same.

[0044] The total oxygen transfer coefficient of group A was 0.246d -1 , which is 3 times that of group B. The temperature obviously promoted oxygen mass transfer.

[0045] The two groups used room temperature biofilm formation. During the biofilm formation period, COD: TN: TP = 100: 5: 1, COD was 600 mg / L, ammonia nitrogen was 30 mg / L, and total phosphorus was 6 mg / L. After successful biofilm formation, the loads of the two groups were adjusted. The influent COD of the two groups was 350 ± 22 mg / L, NH 4 + -N was 35±3 mg / L, COD / TN=10, and the pH value of the reactor was adjusted by NaHCO 3 Adjustments were made and the range was controlled within 7.6±0.2. The hydraulic retention time during the biofilm formation period was 24 hours, and the hydraulic retention time after stabilization was 20 hours.

[0046] like Figure 4 As shown in the figure, the effluent COD of the experimental group was 21.7 mg / L, the removal rate was about 94.8%, and the NH4 + -N was 0.54 mg / L, with a removal rate of about 98.5%, TN was 9.84 mg / L, with a removal rate of 69.4%; the effluent COD of the control group was 55.23 mg / L, with a removal rate of about 84.2%, and NH 4 + -N is 11.41 mg / L, with a removal rate of about 67.4%, and TN is 15.42 mg / L, with a removal rate of 55.9%.

[0047] Embodiment 2:

[0048] The difference between this embodiment and the first embodiment is that the material of the heating plate 12 is different. In this embodiment, the heating plate 12 adopts a full-band high-absorption carbon felt, and a photoelectric storage system is added, which is specifically described as follows:

[0049] The hot air generation part adopts dual-mode light energy conversion technology, and realizes continuous air heating without external energy input by integrating light-heat conversion and photoelectric storage system. The system is composed of a photothermal conversion unit, a photoelectric conversion unit and an energy storage control unit to form a collaborative working system, specifically including: a solar photovoltaic panel array, a solar power controller and a battery pack.

[0050] In the daytime working mode, the system simultaneously performs the dual functions of direct photothermal conversion and photovoltaic energy storage: on the one hand, high-absorption carbon felt is used as the photothermal conversion medium, and its honeycomb porous structure can effectively capture the wide-band light energy in solar radiation, and convert the photon energy into the kinetic energy of molecular thermal motion through the surface plasmon resonance effect, thereby realizing in-situ heating of the air medium; on the other hand, the photovoltaic panel array converts light energy into DC power and implements step-by-step energy storage to the battery pack.

[0051] In the night working mode, the energy storage control unit automatically switches to the discharge state and outputs electric energy to the heating plate 12. The heating plate 12 generates heat flow under the drive of the DC electric field. Through the dual-time energy complementary mechanism, the system realizes 24-hour continuous air heating.

[0052] In this mode, biofilm formation is carried out at room temperature, and the optimal nutrient concentration of COD: TN: TP = 100: 5: 1 is used during the biofilm formation stage, where COD is fixed at 600 mg / L. After seven days of biofilm formation, the influent COD is adjusted to 350 ± 22 mg / L, COD: TN is fixed at 10: 1, the pH value of the reactor is controlled at 7.6 ± 0.2, the hydraulic retention time during the biofilm formation period is 24 hours, and the hydraulic retention time after stabilization is 20 hours.

[0053] The heat for targeted heating in this mode comes from sunlight, which requires high absorption rate materials during the day. Figure 6The absorbance and microstructure of the carbon felt material used in the experiment show that the absorbance is close to 100%. At the same time, the high porosity structure is conducive to the high absorption of light by the material and the realization of the appropriate temperature. Figure 7 is the daytime light intensity, Figure 8 The ambient temperature and material temperature are found to have a good heating effect. As the light intensity changes, the temperature of the material changes. The maximum temperature can rise to 46.5°C at noon. At night, the photovoltaic panels store thermal energy during the day, converting light energy into electric current. When the light is weak at night, it switches to a discharge state to supply power to the heating plate 12, driving the heat flow to generate heating. Fig. 9 As for the temperature change, it can be found that the air can be heated to 32℃ through targeted limited heating, while the water temperature has almost no change. Fig.10 As shown, the effluent ammonia nitrogen in the targeted heating experimental group can be reduced to almost 0 mg / L, with a removal rate of up to 98.6%, while the effluent ammonia nitrogen in the blank group is 12.3 mg / L, with a removal rate of 65.8%.

Claims

1. An aerated membrane bioreactor with a bio-comfortable interface, characterized in that: The reactor comprises a biological treatment part I and a hot air generating part II; The hot air generating part II comprises an air inlet 1 (7), an air outlet 1 (8), a heating plate (12), a heat exchange component (13), and a hot air storage component (14); The heat exchange component (13) is cylindrical, and circular holes are evenly distributed on the side of the cylinder, and the heating plate (12) is wrapped around the side of the cylinder; the area ratio of the front view of the heat exchange component (13) to the front view of the hot air storage component (14) is 26%; The biological treatment part I relies on MABR technology and is composed of an air inlet channel, a membrane module, a water reservoir and an air pressure regulating module (15); The air outlet 1 (8) of the hot air generating part II is connected to the air inlet 2 (6) and the air inlet passage of the biological treatment part I, and the air inlet is regulated by the air pressure regulating component (15); The biological treatment part I has an air inlet channel in the middle and a water reservoir on the outside, which are separated by the MABR membrane assembly.

2. An aerated membrane bioreactor with a bio-comfortable interface according to claim 1, characterized in that: The diameter of the circular holes is 1 cm, and the center interval between the circular holes is 1.5 cm.

3. An aerated membrane bioreactor with a bio-comfortable interface according to claim 1, characterized in that: The heating plate (12) is divided into three categories, namely: ① only electrically heated: nickel-chromium alloy or copper; ② only photothermal: polypyrrole coating, graphene oxide film or copper sulfide; ③ both photothermal and electrically heated: carbon felt, carbon nanotubes, MXene or graphite.

4. A method for treating low-temperature domestic sewage using an aerated membrane bioreactor having a bio-comfortable interface as claimed in any one of claims 1 to 3, characterized in that: The method is specifically as follows: The air in the heat exchange component (13) is heated by the heating plate (12), and then the air in the hot air storage component (14) is heated. When the predetermined temperature is reached, the air enters the air inlet channel of the biological treatment part I through the air outlet 1 (8) and the air pressure regulating component (15). At the same time, low-temperature domestic sewage is introduced into the water reservoir. The hot air in the air inlet channel diffuses to the MABR membrane component, and sewage treatment is achieved through the MABR membrane component.

5. A method for treating low-temperature domestic sewage using an aerated membrane bioreactor with a bio-comfort interface according to claim 4, characterized in that: The membrane assembly adopts a non-porous silica flat membrane assembly. Two non-porous silica flat membranes are placed on a support frame, and heat and air are transferred to the biofilm attached to the silica flat membrane through hot air; If the membrane assembly uses a hollow fiber membrane, the channel inside the membrane is the air inlet channel and no support frame is required; the air pressure inside the membrane is maintained constant through the air pressure regulating assembly.

6. The method for treating low-temperature domestic sewage using an aerated membrane bioreactor with a bio-comfort interface according to claim 4, characterized in that: The reservoir adopts intermittent flow process with a hydraulic retention time of 20 hours.

7. The method for treating low-temperature domestic sewage using an aerated membrane bioreactor with a bio-comfort interface according to claim 4, characterized in that: The temperature of low-temperature domestic sewage is kept stable through water circulation in the water storage tank. The low-temperature circulation water flows in from the lower end of the biological treatment part and flows out from the upper end.

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