Internal circulating fluidized bed photobioreactor for sewage treatment

Abstract

An internal circulation fluidized bed photobioreactor for sewage treatment comprises an internal circulation area and a fluidized bed area located vertically above the internal circulation area, and a spacer for weakening the flow velocity of fluid is arranged between the internal circulation area and the fluidized bed area. The inner circulation area is provided with a water inlet pipe, an inlet water distributor, an inner circulation pipe, a submersible mixing pump and an algae discharge port, the fluidized bed area is provided with a water outlet, the inner circulation area of the reactor is made of a light-transmitting material, and a plurality of light sources are arranged around the inner circulation area.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment equipment technology, specifically to an internal circulating fluidized bed photobioreactor for wastewater treatment. Background Technology

[0002] In traditional wastewater treatment plants, the organic matter in wastewater is mainly converted into small molecules such as CO2, H2O, and organic acids through the respiration of microorganisms. Inorganic substances such as nitrogen and phosphorus in the wastewater are primarily removed through a combination of physicochemical and biological treatment processes. After treatment, nitrogen in the wastewater is released into the air as nitrogen gas, and phosphorus is removed as phosphate. However, traditional biological and physicochemical treatment processes struggle to achieve resource utilization of pollutants. Treatment efficiency is low; traditional nitrogen and phosphorus removal processes require extended reaction times or increased wastewater recirculation to improve nitrogen and phosphorus removal efficiency, making it difficult to maintain long-term stability. Furthermore, achieving good nitrogen and phosphorus removal results requires significant energy consumption.

[0003] Meanwhile, due to the impact of recalcitrant pollutants, traditional biological treatment processes struggle to achieve efficient treatment of these pollutants. Previous studies have found that optimizing the reactor to increase the contact area between microalgae and the light source can improve the treatment of organic pollutants and nitrogen and phosphorus while extending the contact time between pollutants and microalgae. This enables efficient carbon sequestration during wastewater treatment, reduces pollutant emissions, and facilitates the resource utilization of pollutants in wastewater.

[0004] Existing technologies suffer from several drawbacks. Traditional microalgae-based wastewater biological treatment technologies are susceptible to environmental conditions, have low adaptability to photobioreactors, and face difficulties in microalgae separation, limiting their application in practical wastewater treatment processes. Previous studies have found that microalgae such as *Chlamydomonas* spp., *Chlorella* spp., *Scenedesmus* spp., *Desmodesmus* spp., and *Nannochloris* spp. have certain removal and resource utilization effects on recalcitrant pollutants such as antibiotics, pesticides, and hormones. While microalgae-based biological treatment technologies can achieve the transformation and utilization of pollutants in wastewater, their effectiveness in treating increasingly serious recalcitrant pollutants remains poor.

[0005] To address the problems of low treatment efficiency, susceptibility to environmental factors, and low resource utilization rate in actual wastewater treatment processes, the traditional PBR system is optimized, and a novel photobioreactor system is designed. This extends the light contact time of microalgae in the photobioreactor, thereby improving pollutant treatment efficiency, shortening hydraulic retention time, and increasing the resource utilization rate of pollutants in the system.

[0006] Therefore, based on microalgae wastewater biological treatment technology, a circulating photobioreactor was designed to improve the photosynthetic utilization rate of microalgae and enhance the system's wastewater treatment effect. Utility Model Content

[0007] To address the shortcomings of the aforementioned technologies, this invention provides an internal circulating fluidized bed photobioreactor for wastewater treatment.

[0008] A further feature of this invention is an internal circulation fluidized bed photobioreactor for wastewater treatment. The reactor includes an internal circulation zone and a fluidized bed zone located vertically above the internal circulation zone. A spacer is provided between the internal circulation zone and the fluidized bed zone to reduce the fluid flow velocity. The internal circulation zone is provided with an inlet pipe, an inlet water distributor, an internal circulation pipe, a submersible mixing pump, and an algae discharge port. The fluidized bed zone is provided with an outlet. The internal circulation zone of the reactor is made of a light-transmitting material, and several light sources are arranged around the internal circulation zone.

[0009] Further features of this invention: the spacer is a non-woven fabric or a perforated partition, and the inner circulation zone and the fluidized bed sidewall are provided with a number of sampling ports.

[0010] A further feature of this invention is that a reflux pipe and a reflux pump are provided between the fluidized bed zone and the internal circulation zone. The reflux pipe guides the settled algae in the fluidized bed zone back to the internal circulation zone.

[0011] Further features of this invention: The reactor is cylindrical, with an overflow outlet at the top. The reactor also includes an overflow tank to collect the overflow liquid. One end of the return pipe is connected to the overflow tank, and the other end is connected to the inner circulation zone. The outlet is located at the overflow tank and is connected to an outlet pipe and a water storage tank. The overflow tank is equipped with an exhaust pipe and a thermometer, which detects the temperature inside the reactor and is connected to the control system data.

[0012] A further feature of this invention is that the light source includes an actual light source and a simulated light source. The actual light source is sunlight, and the simulated light source is a plurality of LED fluorescent tubes arranged horizontally and vertically.

[0013] Further features of this invention: The reactor consists of, from bottom to top, an internal circulation photobioreactor zone, a fluidized bed zone, and a microalgae separation zone; the internal circulation photobioreactor zone consists of, from bottom to top, an inlet zone and an internal circulation zone.

[0014] The present invention has the following beneficial effects:

[0015] (1) The internal circulation fluidized bed photobioreactor combines a photobioreactor with a fluidized bed reactor. It can effectively remove organic pollutants while removing nitrogen and phosphorus, which cannot be effectively treated by the traditional activated sludge process. The internal circulation component improves the conversion and utilization of light by microalgae. At the same time, combined with the fluidized bed, it treats and utilizes pollutants in wastewater, improving the treatment efficiency of pollutants in wastewater. Water flows through the fluidized bed to achieve algae-water separation, obtaining relatively pure effluent, which is discharged to the clear water tank through the effluent pipe.

[0016] The internal circulation fluidized bed photobioreactor of this invention is used to treat traditional pollutants and recalcitrant pollutants in actual wastewater. It is intended to treat traditional pollutants and recalcitrant pollutants in urban and rural domestic sewage and pre-treated industrial wastewater with low pollutant concentrations in Zhuhai.

[0017] (2) The internal circulation fluidized bed photobioreactor is equipped with an internal circulation pipe. The internal circulation pipe, through a circulation pump, allows a portion of the algal solution to circulate within the internal circulation zone. This effectively mixes microalgae and pollutants in the algal solution while promoting the homogenization of pollutants, thus improving the reactor's pollutant treatment efficiency. Furthermore, the circulation of the algal solution through the internal circulation pipe within the internal circulation zone enhances the photosynthetic utilization rate of the microalgae. The internal circulation fluidized bed reactor is powered by multiple LED lights or sunlight, providing a light environment for the growth and metabolism of microalgae.

[0018] (3) The internal circulating fluidized bed photobioreactor not only improves the pollutant treatment effect, but also allows the algae and metabolites produced by the higher light duration and frequency to serve as raw materials for biofuels. Furthermore, since microalgae can utilize nitrogen and phosphorus in their bodies to convert them into biomass, the conversion and utilization of pollutants in wastewater by microalgae are enhanced. Simultaneously, the fluidized bed zone allows for the sedimentation and separation of microalgae through the fluidized bed, and the sedimented microalgae are collected and recirculated by a return pump connected to the return pipe, extending the biological residence time of microalgae in the reactor and improving the wastewater treatment efficiency of microalgae.

[0019] The combined action of two reaction systems not only removes pollutants, nutrients, and recalcitrant pollutants from wastewater, but also enables the conversion and resource utilization of nitrogen and phosphorus by microalgae. Furthermore, the microalgae and microorganisms construct an algae-bacterial system, enhancing the system's effectiveness in treating pollutants. Moreover, microalgae can control the composition and abundance of microorganisms in wastewater, controlling ARGs and ARBs while enriching symbiotic bacteria, improving the conversion and utilization of traditional pollutants, strengthening the system's conversion and utilization of recalcitrant pollutants, and increasing the system's light utilization rate.

[0020] It is not necessary for any product implementing this invention to simultaneously achieve all the advantages described above. It is understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this invention, the scope of which is defined by the appended claims and their equivalents. Attached Figure Description

[0021] Figure 1 The structure of this utility model embodiment Figure 1 ;

[0022] Figure 2 The structure of this utility model embodiment Figure 2 ;

[0023] Figure 3 The structure of this utility model embodiment Figure 3 ;

[0024] Figure 4 The structure of this utility model embodiment Figure 4 ;

[0025] Figure 5 The structure of this utility model embodiment Figure 5 ;

[0026] Figure 6 The structure of this utility model embodiment Figure 6 ;

[0027] Figure 7 This is a top view of an embodiment of the present utility model;

[0028] Figure 8 This is a sectional view at point 1-1;

[0029] Figure 9 Sectional views at points 1-2;

[0030] Figure 10 Sectional views at points 1-3;

[0031] Figure 11 Sectional views at points 1-4;

[0032] Figure 12 Sectional views at points 1-5;

[0033] Figure 13 Sectional views at points 1-6;

[0034] The components are as follows: 1. Inlet pipe; 2. Inlet water distributor; 3. Reactor support frame; 4. Sampling port; 5. Internal circulation pipe; 5-1. Internal circulation inlet pipe; 5-2. Internal circulation outlet pipe; 6. Circulation pump fixing device; 7. Circulation pump; 8. Circulation pump wire; 8-1. Plug; 9. Bolt; 10. Media carrier; 11. Return pump; 12. Return pipe; 13. Fixing device; 14. Outlet; 15. Exhaust pipe; 16. Thermometer; 17. Algae discharge port.

[0035] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0036] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0037] The present invention will now be described in detail with reference to the accompanying drawings, such as... Figure 1-13 As shown,

[0038] A photobioreactor system for treating and utilizing pollutants in wastewater, which improves the photosynthetic efficiency of microalgae and algae-water separation, includes an internal circulation zone I and a fluidized bed zone II. The bottom of the internal circulation zone I of the internal circulation fluidized bed photobioreactor has an inlet pipe 1 connected to a peristaltic pump. An inlet distributor 2 is installed in the internal circulation zone, through which treated wastewater enters the internal circulation zone I. The internal circulation zone I and the fluidized bed zone II are separated by a non-woven fabric or a perforated partition. The effluent from the internal circulation enters the fluidized bed zone II through the perforated partition between the internal circulation zone I and the fluidized bed zone II. The internal circulation zone I and the fluidized bed zone II are fixed together by bolts 9. An internal circulation pipe 5 is installed in the internal circulation zone I and is connected to a submersible circulation pump 7, and is connected to a power source via an electrical wire 8.

[0039] Several outlets 4 are distributed on the side walls of the internal circulation zone I and the fluidized bed zone II to facilitate sampling and measurement of water quality and biological growth.

[0040] The sidewalls of the internal circulation fluidized bed photobioreactor shown are made of translucent materials, such as resin, plexiglass, or glass. Multiple light sources are installed around the internal circulation area to simulate the lighting and intensity in a real environment. The simulated light sources are multiple horizontally and vertically arranged LED fluorescent tubes. The actual light source uses sunlight, and the reactor is placed in a sunny environment, with LEG light sources installed around it to enable operation and wastewater treatment in a nighttime environment.

[0041] The sidewalls of the two-stage membrane photobioreactor are made of a light-transmitting material, such as resin or glass. Multiple light sources are installed around the aerobic zone 9 to simulate the lighting and intensity in a real environment. The light sources are multiple horizontally and vertically arranged LED fluorescent tubes.

[0042] The internal circulation pipe 5 installed on the reactor wall in the internal circulation zone I allows the algal solution to circulate fully within the zone. This circulation along the reactor wall promotes photosynthesis in the microalgae. Simultaneously, the circulation process also facilitates contact between the microalgae and pollutants, enhancing the conversion and utilization of pollutants by the microalgae. Furthermore, the circulation process washes the reactor wall, reducing the adhesion of microalgae to the reactor wall and mitigating the impact of microalgae adhesion on photosynthetic efficiency.

[0043] Secondly, a fluidized bed zone II is set up at the top of the reactor. The interaction between the solid and liquid phases in the upper part of the reactor facilitates the settling of microalgae and algae bacteria, improving effluent quality, extending the biological residence time of microalgae in the reactor, and enhancing wastewater treatment efficiency. Simultaneously, the combination of the fluidized bed zone and the internal circulation zone increases the effective volume of the reactor and extends the water treatment time.

[0044] Finally, an algae discharge port 17 is set at the bottom of the reactor to facilitate the discharge and treatment of settled dead algae, reduce the impact of settled dead algae on the wastewater treatment effect, and improve the stability of wastewater treatment.

[0045] The internal circulation zone I utilizes microalgae coupled with microorganisms to treat organic pollutants, inorganic pollutants such as nitrogen and phosphorus, and recalcitrant pollutants in wastewater. The internal circulation zone extends the light exposure time through the circulation of microalgae, achieving light-dark intervals in the algal solution within the reactor and improving wastewater treatment efficiency. A fluidized bed zone is also included, where the solid-liquid interaction between the algae and the wastewater promotes the sedimentation of microalgae within the reactor, achieving separation of microalgae from water and further enhancing pollutant treatment. Simultaneously, fluidized bed zone II is equipped with a return pipe 12 to allow the sedimented algae to return to internal circulation zone I, extending the biological residence time of the microalgae.

[0046] The inner circulation zone I is made of plexiglass or other translucent materials. Approximately half of the microalgae in the inner circulation zone I are added during the microalgae cultivation process. During continuous operation, actual wastewater enters the inner circulation zone I evenly through the distributor 2 under the action of the influent pump. The treated effluent from the inner circulation zone I enters the fluidized bed zone II through the non-woven fabric or perforated partition between the inner circulation zone I and the fluidized bed zone II.

[0047] The internal circulation zone I is equipped with an internal circulation pipe 5, which, through a circulation pump 7, homogenizes the algae and pollutants within the internal circulation zone I, improving the basic interaction between microalgae and pollutants. Simultaneously, by impacting the reactor surface, it reduces microalgae adhesion to the reactor, mitigating the impact of microalgae adhesion on light utilization and photosynthetic efficiency. Multiple LED fluorescent lamps can be installed around the internal circulation fluidized bed photobioreactor to provide a light source and a suitable light environment for microalgae growth and metabolism. Microalgae can also be cultured under sunlight, providing a practical light environment for microalgae cultivation.

[0048] Internal circulating fluidized bed photobioreactors can improve effluent quality and reduce pollutant emissions while simultaneously converting microalgae into biomass. The resulting microalgae and their metabolites can be enriched and used as feed, organic fertilizer, biofuel, and other raw materials.

[0049] Under the combined action of the internal circulation zone I and the fluidized bed zone II, the internal circulation fluidized bed photobioreactor can not only degrade and utilize pollutants in wastewater, but also reduce the N and P concentrations in the effluent through microalgae. The microalgae enriched by the fluidized bed can accumulate in the microalgae zone, which is beneficial for discharge to the outside through sampling pipes set on the side wall of the reactor, thereby realizing the enrichment and recovery of algae.

[0050] This reactor employs a microalgae and microorganism synergistic system, using non-woven fabric or perforated baffles to separate the internal circulation zone and fluidized bed zone, reducing the impact of the internal circulation process on the fluidized bed zone and improving photosynthetic utilization efficiency. Simultaneously, the fluidized bed enables algae-water separation through solid-liquid interaction. After aggregation, the microalgae are returned to the internal circulation zone via a reflux pump, extending their biological residence time and improving the reactor's pollutant treatment efficiency. Therefore, the microalgae and microorganism synergistic system can promote the degradation and resource utilization of traditional and recalcitrant pollutants.

[0051] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. An internal circulation fluidized bed photobioreactor for wastewater treatment, characterized by: The reactor comprises an inner circulation zone and a fluidized bed zone vertically above the inner circulation zone, a spacer is arranged between the inner circulation zone and the fluidized bed zone to weaken the fluid flow rate, the inner circulation zone is provided with a water inlet pipe, a water inlet distributor, an inner circulation pipe, a submerged mixed pump and an algae discharge port, the fluidized bed zone is provided with a water outlet, the inner circulation zone of the reactor is made of a light-transmitting material, and a plurality of light sources are arranged around the inner circulation zone.

2. The internal circulation fluidized bed photo-bioreactor for wastewater treatment according to claim 1, characterized in that: The spacer is a non-woven fabric or a perforated partition plate, and a plurality of sampling ports are arranged on the side walls of the inner circulation zone and the fluidized bed zone.

3. The internal circulation fluidized bed photo-bioreactor for wastewater treatment according to claim 1 or 2, characterized in that: A backflow pipe and a backflow pump are arranged between the fluidized bed zone and the inner circulation zone, and the backflow pipe guides the settled algae in the fluidized bed zone to backflow to the inner circulation zone.

4. The internal circulation fluidized bed photo-bioreactor for wastewater treatment according to claim 3, characterized in that: The reactor is in a cylindrical shape, and an overflow port is arranged at the top of the cylinder, the reactor further comprises an overflow tank for receiving the liquid overflowing from the overflow port, one end of the backflow pipe is in communication with the overflow tank, and the other end is in communication with the inner circulation zone, the water outlet is arranged at the overflow tank, and an outlet pipe and a water storage barrel are connected to the water outlet, an exhaust pipe and a thermometer are arranged on the overflow tank, the thermometer detects the temperature in the reactor and is connected to a control system.

5. The internal circulation fluidized bed photo-bioreactor for wastewater treatment according to claim 4, characterized in that: The light source comprises an actual light source and a simulated light source, the actual light source is a sunlight source, and the simulated light source is a plurality of LED fluorescent lamp tubes arranged in a horizontal and vertical manner.

6. The internal circulation fluidized bed photo-bioreactor for wastewater treatment according to claim 5, characterized in that: The reactor comprises an inner circulation photobiological reaction zone, a fluidized bed zone and a microalgae separation zone from bottom to top, and the inner circulation photobiological reaction zone comprises a water inlet zone and an inner circulation zone from bottom to top.

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