Bacterial-algal symbiotic membrane aeration biofilm reactor and biofilm thickness control method

Abstract

The embodiment of the present application provides a kind of bacteria-algae symbiotic membrane aeration biofilm reactor and biofilm thickness control method, the bacteria-algae symbiotic membrane aeration biofilm reactor includes container, membrane component, carbon dioxide supply device, oxygen supply device and light source, membrane component is located in container, membrane component includes first membrane filament group and second membrane filament group arranged at intervals, carbon dioxide supply device is connected with the gas inlet of first membrane filament group, to provide carbon dioxide to first membrane filament group, carbon dioxide is connected with the gas inlet of second membrane filament group, to provide oxygen to second membrane filament group, light source irradiates first membrane filament group.The bacteria-algae symbiotic membrane aeration biofilm reactor of the embodiment of the present application has stronger sewage treatment effect.

Description

Technical Field

[0001] This invention relates to the field of water treatment, specifically to a bacterial-algae symbiotic membrane aerated biofilm reactor and a method for controlling biofilm thickness. Background Technology

[0002] In related technologies, algae-bacterial symbiotic biofilm reactors involve placing a biorode carrier inside, onto which algae and bacteria attach and are exposed to sunlight. An aeration device is located below the biorode carrier to assist the algae in providing oxygen for the bacteria to grow, thereby treating wastewater through the algae-bacterial biofilm. However, the simultaneous attachment of algae and bacteria to the biorode carrier leads to competition within the same area. The oxygen provided by the aeration device increases the dissolved oxygen concentration in the reactor, inhibiting photosynthesis by the algae and causing carbon dioxide stripping, resulting in the loss of inorganic carbon. Therefore, the wastewater treatment effect of algae-bacterial symbiotic biofilm reactors in these technologies is relatively poor. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a microbial-algae symbiotic membrane aerated biofilm reactor.

[0005] The embodiments of the present invention also propose a method for controlling biofilm thickness.

[0006] The algae-bacterial symbiotic membrane aerated biofilm reactor of this invention includes:

[0007] container;

[0008] A membrane module, wherein the membrane module is disposed within the container, the membrane module comprising a first membrane filament group and a second membrane filament group arranged at intervals;

[0009] A carbon dioxide supply device is connected to the air inlet of the first membrane fiber assembly to supply carbon dioxide to the first membrane fiber assembly.

[0010] An oxygen supply device is connected to the air inlet of the second membrane fiber assembly to supply oxygen to the second membrane fiber assembly;

[0011] A light source that illuminates the first membrane fiber assembly.

[0012] The algae-bacterial symbiotic membrane aerated biofilm reactor of this invention has a first membrane filament group for releasing carbon dioxide and attaching it to algal biofilm, preventing algae from suspending and escaping, while also providing a stable carbon source to the algae to complement the light source and ensure algal growth and reproduction. A second membrane filament group is used to release oxygen and attach it to bacterial biofilm, improving oxygen utilization by the bacteria. Because the second and first membrane filament groups are spaced apart, the supplied gas is directly supplied to the biofilm through a concentration gradient, preventing excess gas leakage and avoiding competition between algae and bacteria in the same area, as well as avoiding dissolved oxygen stress on the algae. Furthermore, the first and second membrane filament groups employ a bubble-free aeration method to avoid stripping, ensuring the normal growth and reproduction of both algal and bacterial biofilms. The balanced growth of algae and bacteria feeds back into the membrane components to maximize phosphorus assimilation, improving nitrogen and phosphorus removal efficiency. Therefore, the algae-bacterial symbiotic membrane aerated biofilm reactor of this invention has a strong wastewater treatment effect.

[0013] In some embodiments, the first membrane fiber group surrounds the outer periphery of the second membrane fiber group and is arranged at intervals from the second membrane fiber group, and the light source surrounds the outer periphery of the first membrane fiber group and is disposed in the container.

[0014] In some embodiments, at least a portion of the container surrounding the first membrane filament assembly is made transparent, and the light source surrounds the outer periphery of the transparent portion of the container.

[0015] In some embodiments, the light source is a light strip spirally wound around the outer circumferential surface of the container.

[0016] In some embodiments, the air outlets of the first membrane fiber group and the second membrane fiber group extend to the outside of the container.

[0017] In some embodiments, the algae-bacterial symbiotic membrane aerated biofilm reactor further includes a distributor and a water supply pipe. The distributor is disposed inside the container and located below the membrane assembly. The water supply pipe is connected to the distributor and is used to supply the wastewater to be treated into the container through the distributor.

[0018] In some embodiments, the algae-bacterial symbiotic membrane aerated biofilm reactor further includes a drain pipe and a return pipe. The drain pipe is connected to the container for discharging treated wastewater. The return pipe is connected between the drain pipe and the water supply pipe. Alternatively, the return pipe is connected between the drain pipe and the distributor for supplying at least a portion of the treated wastewater discharged from the drain pipe into the container via the distributor.

[0019] In some embodiments, the algae-bacterial symbiotic membrane aerated biofilm reactor further includes a flushing gas source connected to the distributor for supplying flushing gas into the container via the distributor.

[0020] In some embodiments, the algae-bacterial symbiotic membrane aerated biofilm reactor further includes a first sensing device, a second sensing device, and a control terminal. The first sensing device is used to obtain the thickness of the biofilm attached to the first membrane filament group, and the second sensing device is used to obtain the thickness of the biofilm attached to the second membrane filament group. The first sensing device, the carbon dioxide supply device, the second sensing device, and the oxygen supply device are all electrically connected to the control terminal. The control terminal is used to control the gas supply of the carbon dioxide supply device according to the data transmitted by the first sensing device, and to control the gas supply of the oxygen supply device according to the data transmitted by the second sensing device.

[0021] In the biofilm thickness control method of this invention, the biofilm is the biofilm attached to the membrane module of the algae-bacterial symbiotic membrane aerated biofilm reactor according to any of the above embodiments, and the biofilm thickness control method includes:

[0022] The aerated biofilm reactor of the bacterial-algae symbiotic membrane was run multiple times. During each run, multiple data samples were obtained when the chemical oxygen demand removal rate, ammonia nitrogen removal rate, and total phosphorus removal rate were all greater than or equal to 80%. The data samples included carbon dioxide supply, oxygen supply, the thickness of the biofilm attached to the first membrane filament group, and the thickness of the biofilm attached to the second membrane filament group.

[0023] The minimum and maximum values ​​of carbon dioxide supply are obtained from all the data samples to obtain the range of carbon dioxide supply.

[0024] The minimum and maximum values ​​of oxygen supply are obtained from all the data samples to obtain the range of oxygen supply.

[0025] Obtain the ratio of carbon dioxide supply to oxygen supply in the same data sample, and obtain the minimum and maximum ratios of carbon dioxide supply to oxygen supply in all the data samples, thereby obtaining the range of the ratio of carbon dioxide supply to oxygen supply.

[0026] In all the data samples, the thicknesses of biofilms attached to multiple first membrane filament groups and multiple second membrane filament groups are obtained, satisfying the ranges of carbon dioxide supply, oxygen supply, and the ratio of carbon dioxide supply to oxygen supply. The minimum and maximum values ​​of the thicknesses of the biofilms attached to the multiple first membrane filament groups are obtained to obtain the thickness range of the biofilms attached to the first membrane filament groups. The minimum and maximum values ​​of the thicknesses of the biofilms attached to the multiple second membrane filament groups are obtained to obtain the thickness range of the biofilms attached to the second membrane filament groups.

[0027] The biofilm thickness control method of this invention involves repeatedly running the algae-bacterial symbiotic membrane aerated biofilm reactor and obtaining multiple data samples when the chemical oxygen demand (COD) removal rate, ammonia nitrogen removal rate, and total phosphorus removal rate are all greater than or equal to 80%. From all data samples, the ranges of carbon dioxide supply, oxygen supply, and the ratio of carbon dioxide supply to oxygen supply are obtained. Based on these ranges, the thicknesses of the biofilm attached to the first membrane filament group and the second membrane filament group are selected from all data samples, thus obtaining the thickness ranges of the biofilm attached to the first and second membrane filament groups. Maintaining the biofilm attached to the first and second membrane filament groups within their corresponding thickness ranges during wastewater treatment in the algae-bacterial symbiotic membrane aerated biofilm reactor ensures excellent wastewater treatment performance. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the aerated biofilm reactor of the bacterial-algae symbiotic membrane according to an embodiment of the invention.

[0029] Figure label:

[0030] 1. Container; 11. Sludge hopper; 2. Membrane module; 21. First membrane fiber assembly; 22. Second membrane fiber assembly; 3. Carbon dioxide supply device; 4. Oxygen supply device; 5. Light source; 6. Distributor; 7. Water supply pipe; 8. Drainage pipe; 9. Return pipe; 10. Flushing air source; 20. Control terminal. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] The following is for reference. Figure 1 This invention describes an aerated biofilm reactor and a biofilm thickness control method for a bacterial-algae symbiotic membrane according to embodiments of the present invention.

[0033] like Figure 1 As shown, the aerated biofilm reactor of the algae-bacterial symbiotic membrane in this embodiment of the invention includes a container 1, a membrane module 2, a carbon dioxide supply device 3, an oxygen supply device 4, and a light source 5.

[0034] Membrane module 2 is disposed within container 1, and membrane module 2 includes a first membrane filament group 21 and a second membrane filament group 22 arranged at intervals. For example, as... Figure 1As shown, container 1 is preferably, but not limited to, a vertically arranged tank for containing sewage and algae and bacteria for treating sewage. Container 1 is provided with membrane module 2, which includes, but is not limited to, a first membrane filament group 21 and a second membrane filament group 22 arranged at intervals in a horizontal plane.

[0035] The carbon dioxide supply device 3 is connected to the air inlet of the first membrane fiber assembly 21 to supply carbon dioxide to the first membrane fiber assembly 21. For example, as Figure 1 As shown, the carbon dioxide supply device 3 is preferably, but not limited to, a storage tank for storing carbon dioxide. The carbon dioxide supply device 3 is connected to the air inlet of the first membrane filament group 21 through a pipeline to supply carbon dioxide to the first membrane filament group 21. The carbon dioxide is released by the membrane filaments of the first membrane filament group 21, thereby causing algae to attach to the surface of the first membrane filament group 21 and forming an algal biofilm.

[0036] The oxygen supply device 4 is connected to the air inlet of the second membrane fiber assembly 22 to supply oxygen to the second membrane fiber assembly 22. For example, as Figure 1 As shown, the oxygen supply device 4 is preferably, but not limited to, a storage tank for storing oxygen. The oxygen supply device 4 is connected to the air inlet of the second membrane filament group 22 through a pipeline to supply oxygen to the second membrane filament group 22. The oxygen is released by the membrane filaments of the second membrane filament group 22, thereby causing bacteria to attach to the surface of the second membrane filament group 22 and forming a microbial biofilm.

[0037] Light source 5 illuminates the first membrane filament assembly 21. For example, as... Figure 1 As shown, the light source 5 provides illumination to the first membrane filament group 21 so that algae can grow and reproduce on the surface of the first membrane filament group 21.

[0038] The algae-bacterial symbiotic membrane aerated biofilm reactor of this invention has a first membrane filament group for releasing carbon dioxide and attaching it to algal biofilm, preventing algae from suspending and escaping, while also providing a stable carbon source to the algae to complement the light source and ensure algal growth and reproduction. A second membrane filament group is used to release oxygen and attach it to bacterial biofilm, improving oxygen utilization by the bacteria. Since the second and first membrane filament groups are spaced apart, the supplied gas is directly supplied to the biofilm through a concentration gradient, preventing excess gas leakage and avoiding competition between algae and bacteria in the same area, as well as avoiding dissolved oxygen stress on the algae. Furthermore, the first and second membrane filament groups employ a bubble-free aeration method, thus avoiding stripping and ensuring the normal growth and reproduction of both algal and bacterial biofilms. The balanced growth of algae and bacteria feeds back into the membrane components to maximize phosphorus assimilation, improving nitrogen and phosphorus removal efficiency. Therefore, the algae-bacterial symbiotic membrane aerated biofilm reactor of this invention has a strong wastewater treatment effect.

[0039] In some embodiments, the first membrane filament group 21 surrounds the outer periphery of the second membrane filament group 22 and is arranged at intervals from the second membrane filament group 22, and the light source 5 surrounds the outer periphery of the first membrane filament group 21 and is disposed in the container 1.

[0040] like Figure 1 As shown, both the first membrane filament group 21 and the second membrane filament group 22 are annular in the vertical direction. The first membrane filament group 21 surrounds the outer periphery of the second membrane filament group 22 and is arranged at intervals with the second membrane filament group 22. The light source 5 is located in the container 1 and surrounds the outer periphery of the first membrane filament group 21 to irradiate the first membrane filament group 21.

[0041] This ensures full utilization of the internal space of container 1, and maintains the spacing between the first membrane fiber group 21 and the second membrane fiber group 22, while ensuring that the light source 5 fully illuminates the first membrane fiber group 21.

[0042] It is understood that the first membrane fiber group 21, the second membrane fiber group 22, and the light source 5 are not limited to, for example, Figure 1 In some embodiments, the arrangement shown depicts the first membrane filament group 21, the second membrane filament group 22, and the light source 5 arranged sequentially at intervals along the horizontal direction, for example, along the left-right direction.

[0043] In some embodiments, at least a portion of the container 1 surrounding the first membrane filament group 21 is made transparent, and the light source 5 surrounds the outer periphery of the transparent portion of the container 1.

[0044] like Figure 1 As shown, the circumferential walls of container 1 in the vertical direction are all made transparent, and the light source 5 surrounds the outer periphery of the circumferential walls of container 1 so as to irradiate the first membrane filament group 21 through the circumferential walls of container 1.

[0045] It is understood that the circumferential wall of container 1 is not limited to being completely transparent. In some other embodiments, the circumferential wall of container 1 can be configured as two layers, with the inner layer being transparent and the light source 5 positioned between the inner and outer layers and surrounding the inner layer.

[0046] It is understood that the container 1 is not limited to being at least partially transparent; in other embodiments, the light source 5 is disposed inside the container 1.

[0047] In some embodiments, the light source 5 is a light strip spirally wound around the outer peripheral surface of the container 1.

[0048] like Figure 1 As shown, the light source 5 is a light strip, which is located on the outer circumference of the container 1 and extends in a spiral shape in the vertical direction to facilitate the installation of the light source 5.

[0049] It is understood that the light source 5 is not limited to a light strip. In other embodiments, the light source 5 includes a plurality of lamp tubes that extend vertically and are spaced apart around the vertical direction.

[0050] In some embodiments, the air outlet of the first membrane filament group 21 and the air outlet of the second membrane filament group 22 extend to the outside of the container 1.

[0051] like Figure 1 As shown, both the first membrane fiber group 21 and the second membrane fiber group 22 include a diverter, multiple membrane fibers, and a manifold. The multiple membrane fibers extend vertically and are arranged at intervals around the vertical direction. The diverter is connected to the top of the multiple membrane fibers and has an interface extending to the outside of the container 1. The manifold is connected to the bottom of the multiple membrane fibers and has a discharge port extending to the outside of the container 1.

[0052] In the first membrane fiber assembly 21, the interface of the diverter forms the air inlet of the first membrane fiber assembly 21 and is connected to the carbon dioxide supply device 3 through a pipeline. The discharge port of the manifold forms the air outlet of the first membrane fiber assembly 21. The carbon dioxide supplied by the carbon dioxide supply device 3 enters the diverter through the air inlet of the first membrane fiber assembly 21 and is diverted by the diverter to the inner cavity of multiple membrane fibers. The carbon dioxide flows from top to bottom along the membrane fibers and is released into the container 1 through the wall of the membrane fibers. The unreleased carbon dioxide enters the manifold and is discharged out of the container 1 through the air outlet of the first membrane fiber assembly 21 to avoid carbon dioxide being discharged into the container 1 and affecting the sewage treatment effect.

[0053] In the second membrane fiber assembly 22, the interface of the diverter forms the air inlet of the second membrane fiber assembly 22 and is connected to the oxygen supply device 4 through a pipeline. The discharge port of the manifold forms the air outlet of the second membrane fiber assembly 22. The oxygen supplied by the oxygen supply device 4 enters the diverter through the air inlet of the second membrane fiber assembly 22 and is diverted by the diverter to the inner cavity of multiple membrane fibers. The oxygen flows from top to bottom along the membrane fibers and is released into the container 1 through the wall of the membrane fibers. The oxygen that is not released enters the manifold and is discharged out of the container 1 through the air outlet of the second membrane fiber assembly 22 to avoid oxygen being discharged into the container 1 and affecting the sewage treatment effect.

[0054] Furthermore, the outlet of the first membrane fiber assembly 21 can be connected to the carbon dioxide supply device 3 through a pipeline, and the outlet of the second membrane fiber assembly 22 can be connected to the oxygen supply device 4 through a pipeline, so as to reuse the discharged carbon dioxide and oxygen.

[0055] In some embodiments, the aerated biofilm reactor of the algae-bacterial symbiotic membrane of the present invention further includes a distributor 6 and a water supply pipe 7. The distributor 6 is disposed inside the container 1 and located below the membrane module 2. The water supply pipe 7 is connected to the distributor 6 and is used to supply the wastewater to be treated into the container 1 through the distributor 6.

[0056] like Figure 1As shown, a distributor 6 is provided inside the container 1. The distributor 6 is located below the membrane module 2. The water supply pipe 7 preferably passes through the container 1 and is connected to the distributor 6. The water supply pipe 7 supplies the wastewater to be treated to the distributor 6, and then discharges it upward from the distributor 6 into the container 1, forming an upward water flow in the container 1. This allows the wastewater to be treated to fully contact the bacterial biofilm and algal biofilm, thereby improving the mass transfer effect and wastewater treatment effect.

[0057] In some embodiments, the aerated biofilm reactor of the algae-bacterial symbiotic membrane of the present invention further includes a drain pipe 8 and a return pipe 9. The drain pipe 8 is connected to the container 1 and is used to discharge the treated wastewater. The return pipe 9 is connected between the drain pipe 8 and the water supply pipe 7, or the return pipe 9 is connected between the drain pipe 8 and the distributor 6 and is used to supply at least a portion of the treated wastewater discharged from the drain pipe 8 into the container 1 via the distributor 6.

[0058] like Figure 1 As shown, the top of container 1 is connected to drain pipe 8 to discharge the treated wastewater.

[0059] The return pipe 9 is preferably, but not limited to, connected between the drain pipe 8 and the water supply pipe 7. A portion of the treated wastewater is discharged through the drain pipe 8 or supplied to the next process, while the other portion flows back into the water supply pipe 7 via the return pipe 9. This returned wastewater, along with the untreated wastewater in the water supply pipe 7, is then supplied into the container 1 via the distributor 6. Since the discharged treated wastewater contains a bacterial and algal suspension, a portion of this suspension can be returned to the container 1, thereby improving the wastewater treatment effect. Preferably, the return pipe 9 has a regulating valve.

[0060] It should be noted that during the use of the bacterial-algae symbiotic membrane aerated biofilm reactor, when the sewage pollution is severe or the bacteria and algae have not yet grown to meet the sewage treatment requirements, all the treated sewage can be returned through the return pipe 9.

[0061] In some embodiments, the return pipe 9 can also be connected between the drain pipe 8 and the distributor 6. The wastewater to be treated provided by the water supply pipe 7 and the treated wastewater returned by the return pipe 9 are mixed in the distributor 6 and discharged into the container 1.

[0062] In some embodiments, the aerated biofilm reactor of the algae-bacterial symbiotic membrane of the present invention further includes a flushing air source 10, which is connected to a distributor 6 and is used to supply flushing air into the container 1 via the distributor 6.

[0063] like Figure 1As shown, the flushing air source 10 is preferably, but not limited to, a storage tank for storing flushing air. The flushing air source 10 is connected to the distributor 6 through a pipeline to supply flushing air to the distributor 6. The flushing air, in the form of bubbles, is released into the container 1 along with the sewage by the distributor 6 and forms an upward airflow, which is used to flush the bacterial biofilm and algal biofilm to peel off the aging and loose parts of the biofilm and settle them to the bottom of the container 1, so as to ensure the activity of the bacterial biofilm and algal biofilm and the treatment effect on the sewage.

[0064] Preferably, the flushing air source 10, the distributor 6, and the water supply pipe 7 are connected by a three-way valve to control the on / off state of the flushing air source 10 and the distributor 6, as well as the on / off state of the distributor 6 and the water supply pipe 7.

[0065] Furthermore, the bottom of container 1 has a sludge discharge hopper 11, which is preferably, but not limited to, a cone shape with a decreasing cross-section from top to bottom, for collecting and settling sludge and the aged, loose portion of the sludge and detached biofilm from the wastewater. The sludge discharge hopper 11 is located below the distributor 6 to avoid fluctuations in water and air flow, facilitating the settling of the aged, loose portion of the sludge and biofilm. The bottom of the sludge discharge hopper 11 has a discharge port for discharging the settled sludge and the aged, loose portion of the biofilm.

[0066] In some embodiments, the aerated biofilm reactor of the algae-bacterial symbiotic membrane of the present invention further includes a first sensing device, a second sensing device, and a control terminal 20. The first sensing device is used to obtain the thickness of the biofilm attached to the first membrane filament group 21, and the second sensing device is used to obtain the thickness of the biofilm attached to the second membrane filament group 22. The first sensing device, the carbon dioxide supply device 3, the second sensing device, and the oxygen supply device 4 are all electrically connected to the control terminal 20. The control terminal 20 is used to control the gas supply of the carbon dioxide supply device 3 according to the data transmitted by the first sensing device, and to control the gas supply of the oxygen supply device 4 according to the data transmitted by the second sensing device.

[0067] like Figure 1 As shown, container 1 is equipped with a first sensing device and a second sensing device. The first sensing device is located on or opposite to the first membrane filament group 21 to obtain the thickness of the biofilm attached to the first membrane filament group 21, in other words, to obtain the thickness of the algal biofilm. The second sensing device is located on or opposite to the second membrane filament group 22 to obtain the thickness of the biofilm attached to the second membrane filament group 22, in other words, to obtain the thickness of the fungal biofilm. The first and second sensing devices can be optical sensors, electrical sensors, ultrasonic sensors, probes, etc.

[0068] The first sensing device is electrically connected to the control terminal 20 to transmit the actual thickness of the algal biofilm to the control terminal 20, and the second sensing device is electrically connected to the control terminal 20 to transmit the actual thickness of the fungal biofilm to the control terminal 20.

[0069] The carbon dioxide supply device 3 has a carbon dioxide valve that controls its opening and closing and / or the flow rate of carbon dioxide supply.

[0070] The oxygen supply device 4 has an oxygen valve that controls its opening and closing and / or the oxygen supply flow rate.

[0071] Both the carbon dioxide valve and the oxygen valve are electrically connected to the control terminal 20. The control terminal 20 is used to control the opening degree and / or opening and closing of the carbon dioxide valve and the oxygen valve, so as to control whether carbon dioxide and oxygen are supplied and / or the amount supplied.

[0072] The control terminal 20 has a preset range of thickness for algal biofilms and a range of thickness for fungal biofilms.

[0073] When the actual thickness of the algal biofilm transmitted by the first sensing device is lower than the preset algal biofilm thickness range, the control terminal 20 controls the carbon dioxide valve to open or increase the opening degree of the carbon dioxide valve to promote the growth and reproduction of algae, thereby increasing the thickness of the algal biofilm. When the actual thickness of the algal biofilm transmitted by the first sensing device is higher than the preset algal biofilm thickness range, the control terminal 20 controls the carbon dioxide valve to close or decrease the opening degree of the carbon dioxide valve to slow down the growth and reproduction of algae, thereby reducing the thickness of the algal biofilm, so that the actual thickness of the algal biofilm is roughly within the preset algal biofilm thickness range.

[0074] When the actual thickness of the fungal biofilm transmitted by the second sensing device is lower than the preset thickness range of the fungal biofilm, the control terminal 20 controls the oxygen valve to open or increase the opening degree of the oxygen valve to promote the growth and reproduction of fungi, thereby increasing the thickness of the fungal biofilm. When the actual thickness of the fungal biofilm transmitted by the second sensing device is higher than the preset thickness range of the fungal biofilm, the control terminal 20 controls the oxygen valve to close or decrease the opening degree of the oxygen valve to slow down the growth and reproduction of fungi, thereby reducing the thickness of the fungal biofilm, so that the actual thickness of the fungal biofilm is roughly within the preset thickness range of the fungal biofilm.

[0075] The following is for reference. Figure 1 This invention describes a method for controlling biofilm thickness according to an embodiment of the invention.

[0076] It should be noted that the biofilm in the biofilm thickness control method of the present invention is the biofilm attached to the membrane module 2 of the algae-bacterial symbiotic membrane aeration biofilm reactor according to the present invention, including algal biofilm attached to the surface of the first membrane filament group 21 and bacterial biofilm attached to the surface of the second membrane filament group 22.

[0077] The biofilm thickness control method of this invention includes the following steps.

[0078] The algae-bacterial symbiotic membrane aerated biofilm reactor was operated multiple times. During each operation, multiple data samples were collected when the chemical oxygen demand (COD), ammonia nitrogen (ANOVA), and total phosphorus (TP) removal rates were all greater than or equal to 80%. In other words, multiple data samples were collected during each operation of the algae-bacterial symbiotic membrane aerated biofilm reactor, and the data samples were collected at the time that the COD removal rate, ANOVA removal rate, and TP removal rate were all greater than or equal to 80%. The data samples included carbon dioxide supply, oxygen supply, the thickness of the biofilm attached to the first membrane filament group 21, and the thickness of the biofilm attached to the second membrane filament group 22. It should be noted that the carbon dioxide supply, oxygen supply, the thickness of the biofilm attached to the first membrane filament group 21, and the thickness of the biofilm attached to the second membrane filament group 22 within the same data sample were all values ​​at the same time point.

[0079] The minimum and maximum values ​​of carbon dioxide supply are obtained from all data samples to determine the range of carbon dioxide supply. In other words, the range of carbon dioxide supply is greater than or equal to the minimum value of carbon dioxide supply in all data samples, and less than or equal to the maximum value of carbon dioxide supply in all data samples.

[0080] The minimum and maximum oxygen supply values ​​are obtained from all data samples to determine the range of oxygen supply. In other words, the range of oxygen supply is greater than or equal to the minimum oxygen supply value in all data samples, and less than or equal to the maximum oxygen supply value in all data samples.

[0081] Obtain the carbon dioxide / oxygen supply ratio for each data sample. In other words, divide the carbon dioxide supply by the oxygen supply for each data sample to obtain the carbon dioxide / oxygen supply ratio for that data sample. Obtain the minimum and maximum carbon dioxide / oxygen supply ratios for all data samples to obtain the range of the carbon dioxide / oxygen supply ratio. In other words, the range of the carbon dioxide / oxygen supply ratio is greater than or equal to the minimum ratio for all data samples and less than or equal to the maximum ratio for all data samples.

[0082] From all data samples, the thicknesses of biofilms attached to multiple first membrane filament groups 21 and multiple second membrane filament groups 22 are obtained, provided that the carbon dioxide supply range, oxygen supply range, and carbon dioxide supply / oxygen supply ratio range are met. In other words, from all data samples, a subset of data is selected where the carbon dioxide supply is within the specified range, the oxygen supply is outside the specified range, and the carbon dioxide supply / oxygen supply ratio is within the specified range. The thicknesses of algal and fungal biofilms in this subset of data are then obtained.

[0083] The minimum and maximum thicknesses of biofilms attached to multiple first membrane filament groups 21 are obtained to determine the thickness range of the biofilms attached to the first membrane filament groups 21. Similarly, the minimum and maximum thicknesses of biofilms attached to multiple second membrane filament groups 22 are obtained to determine the thickness range of the biofilms attached to the second membrane filament groups 22. In other words, the minimum and maximum thicknesses of algal biofilms in this data set are selected, and the range of algal biofilm thicknesses is greater than or equal to the minimum thickness and less than or equal to the maximum thickness. Likewise, the minimum and maximum thicknesses of fungal biofilms in this data set are selected, and the range of fungal biofilm thicknesses is greater than or equal to the minimum thickness and less than or equal to the maximum thickness.

[0084] The obtained algal biofilm thickness range is preferably, but not limited to, the artificially preset algal biofilm thickness range in the control terminal 20, and the obtained bacterial biofilm thickness range is preferably, but not limited to, the artificially preset bacterial biofilm thickness range in the control terminal 20. Thus, when the bacterial-algal symbiotic membrane aerated biofilm reactor is officially treating wastewater, the control terminal 20 controls the carbon dioxide supply and oxygen supply to ensure that the actual thickness of the algal biofilm is roughly within the preset algal biofilm thickness range, and the actual thickness of the bacterial biofilm is roughly within the preset bacterial biofilm thickness range, thereby ensuring the activity of the bacterial and algal biofilms and the wastewater treatment effect.

[0085] The biofilm thickness control method of this invention involves repeatedly running the algae-bacterial symbiotic membrane aerated biofilm reactor and obtaining multiple data samples when the chemical oxygen demand (COD) removal rate, ammonia nitrogen removal rate, and total phosphorus removal rate are all greater than or equal to 80%. From all data samples, the ranges of carbon dioxide supply, oxygen supply, and the ratio of carbon dioxide supply to oxygen supply are obtained. Based on these ranges, the thicknesses of the biofilm attached to the first membrane filament group and the second membrane filament group are selected from all data samples, thus obtaining the thickness ranges of the biofilm attached to the first and second membrane filament groups. Maintaining the biofilm attached to the first and second membrane filament groups within their corresponding thickness ranges during wastewater treatment in the algae-bacterial symbiotic membrane aerated biofilm reactor ensures excellent wastewater treatment performance.

[0086] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0087] Furthermore, the terms "first" and "second" are used only for distinction and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0088] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0089] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0090] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling biofilm thickness, characterized in that, include: The algae-bacterial symbiotic membrane aerated biofilm reactor was operated multiple times. The algae-bacterial symbiotic membrane aerated biofilm reactor includes a container (1), a membrane module (2), a carbon dioxide supply device (3), an oxygen supply device (4), and a light source (5). The membrane module (2) is located inside the container (1). The membrane module (2) includes a first membrane filament group (21) and a second membrane filament group (22) arranged at intervals. The carbon dioxide supply device (3) is connected to the air inlet of the first membrane filament group (21) to provide carbon dioxide to the first membrane filament group (21). The oxygen supply device (4) is connected to the air inlet of the second membrane filament group (22) to provide oxygen to the second membrane filament group (22). The light source (5) irradiates the first membrane filament group (21). The membrane module (2) is covered with a biofilm. During each operation of the bacterial-algae symbiotic membrane aerated biofilm reactor, multiple data samples were obtained when the chemical oxygen demand removal rate, ammonia nitrogen removal rate, and total phosphorus removal rate were all greater than or equal to 80%. The data samples included carbon dioxide supply, oxygen supply, the thickness of the biofilm attached to the first membrane filament group (21), and the thickness of the biofilm attached to the second membrane filament group (22). The minimum and maximum values ​​of carbon dioxide supply are obtained from all the data samples to obtain the range of carbon dioxide supply. The minimum and maximum values ​​of oxygen supply are obtained from all the data samples to obtain the range of oxygen supply. Obtain the ratio of carbon dioxide supply to oxygen supply in the same data sample, and obtain the minimum and maximum ratios of carbon dioxide supply to oxygen supply in all the data samples, thereby obtaining the range of the ratio of carbon dioxide supply to oxygen supply. In all the data samples, the thickness of the biofilm attached to multiple first membrane filament groups (21) and the thickness of the biofilm attached to multiple second membrane filament groups (22) are obtained, satisfying the range of carbon dioxide supply, the range of oxygen supply, and the range of carbon dioxide supply / oxygen supply ratio. The minimum and maximum values ​​of the thickness of the biofilm attached to multiple first membrane filament groups (21) are obtained to obtain the thickness range of the biofilm attached to the first membrane filament group (21). The minimum and maximum values ​​of the thickness of the biofilm attached to multiple second membrane filament groups (22) are obtained to obtain the thickness range of the biofilm attached to the second membrane filament group (22).

2. The biofilm thickness control method according to claim 1, characterized in that, The first membrane fiber group (21) surrounds the outer periphery of the second membrane fiber group (22) and is arranged at intervals with the second membrane fiber group (22). The light source (5) surrounds the outer periphery of the first membrane fiber group (21) and is disposed in the container (1).

3. The biofilm thickness control method according to claim 2, characterized in that, The container (1) is made transparent at least in the portion surrounding the first membrane filament group (21), and the light source (5) surrounds the transparent portion of the container (1).

4. The biofilm thickness control method according to claim 3, characterized in that, The light source (5) is a light strip spirally wound around the outer circumferential surface of the container (1).

5. The biofilm thickness control method according to claim 1, characterized in that, The air outlets of the first membrane fiber group (21) and the second membrane fiber group (22) extend to the outside of the container (1).

6. The biofilm thickness control method according to claim 1, characterized in that, It also includes a distributor (6) and a water supply pipe (7). The distributor (6) is located inside the container (1) and below the membrane assembly (2). The water supply pipe (7) is connected to the distributor (6) and is used to supply the wastewater to be treated into the container (1) through the distributor (6).

7. The biofilm thickness control method according to claim 6, characterized in that, It also includes a drain pipe (8) and a return pipe (9), the drain pipe (8) being connected to the container (1) for discharging treated wastewater, and the return pipe (9) being connected between the drain pipe (8) and the water supply pipe (7), or the return pipe (9) being connected between the drain pipe (8) and the distributor (6) for supplying at least a portion of the treated wastewater discharged from the drain pipe (8) into the container (1) via the distributor (6).

8. The biofilm thickness control method according to claim 6, characterized in that, It also includes a flushing air source (10), which is connected to the distributor (6) and is used to supply flushing air into the container (1) via the distributor (6).

9. The biofilm thickness control method according to claim 1, characterized in that, It also includes a first sensing device, a second sensing device, and a control terminal (20). The first sensing device is used to obtain the thickness of the biofilm attached to the first membrane filament group (21). The second sensing device is used to obtain the thickness of the biofilm attached to the second membrane filament group (22). The first sensing device, the carbon dioxide supply device (3), the second sensing device, and the oxygen supply device (4) are all electrically connected to the control terminal (20). The control terminal (20) is used to control the gas supply of the carbon dioxide supply device (3) according to the data transmitted by the first sensing device, and to control the gas supply of the oxygen supply device (4) according to the data transmitted by the second sensing device.

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