Building sewage purification and energy production system based on microalgae photo-biological reaction

Abstract

The invention discloses a building sewage purification and energy production system based on microalgae photobiological reaction, and belongs to the field of urban domestic sewage microalgae treatment and biomass energy collaborative production. A main body of the system is composed of an underground three-stage septic tank, a transfer sewage tank, a spherical microalgae self-mixing photo-biological reaction wall, an algae-water separator and a water storage tank. The septic tank collects sewage and feces discharged by a building, after precipitation and layering, upper-layer sewage flows into the transfer sewage tank and then is pumped into the spherical microalgae self-mixing photobiological reaction wall, pollutant degradation and microalgae biomass accumulation are completed in the photobiological reaction process, algae liquid obtained after reaction is subjected to algae-water separation through the separator, and effluent flows into the water storage tank to be recycled. Part of the separated microalgae biomass flows back to the reaction wall to maintain the efficiency stability of the system, and the other part of the separated microalgae biomass is discharged into the septic tank for co-fermentation capacity. According to the system, the sewage collection unit, the microalgae metabolism unit, the algae-water separation unit, the fermentation productivity unit and the like are integrated, so that in-situ purification and resource utilization of building sewage are realized, and green and energy-saving construction of cities is promoted.

Description

Technical Field

[0001] This invention belongs to the field of co-production of microalgae wastewater treatment and biomass energy, specifically relating to a building wastewater purification and production capacity system based on microalgae photobioreaction. Background Technology

[0002] With the continuous advancement of urbanization and economic development, municipal wastewater discharge has shown a significant upward trend. Wastewater is rich in nutrients such as carbon, nitrogen, and phosphorus, possessing enormous potential for resource utilization. However, traditional wastewater treatment processes still primarily focus on achieving discharge standards, with less consideration given to wastewater reuse and resource recovery. Simultaneously, the accelerated pace of urbanization has led to a surge in high-rise buildings, with the widespread use of glass curtain wall structures not only causing light pollution but also significantly increasing energy consumption within these buildings. Against this backdrop, promoting green building transformation and coordinated urban ecological development has become a crucial issue, urgently requiring the development of a new technology that can simultaneously alleviate building energy consumption and achieve in-situ wastewater purification and energy production.

[0003] Microalgae wastewater treatment technology efficiently absorbs nutrients such as carbon, nitrogen, and phosphorus from wastewater through photosynthesis, realizing a paradigm shift in wastewater treatment from end-of-pipe treatment to resource-based production. Innovatively integrating this technology with building glass curtain wall systems can construct photobioreactor walls that combine wastewater purification, temperature control, and biomass energy enrichment, providing a new technological path for building energy conservation, emission reduction, and urban ecological optimization.

[0004] Therefore, this invention designs a building wastewater purification and production capacity system based on microalgae photobioreactors. This system integrates units for wastewater collection, microalgae metabolism, algae-water separation, and fermentation production capacity, achieving in-situ purification and resource utilization of building wastewater, and promoting green and energy-saving urban construction. Summary of the Invention

[0005] To address the problems in the existing technology, this invention proposes a building wastewater purification capacity system based on microalgae photobioreactors.

[0006] To achieve the above objectives, the present invention proposes the following technical solution: A building wastewater purification and production capacity system based on microalgae photobioreactors includes the following structure: Multiple sewage pipes are connected at one end to the sewage outlets inside each floor of the building, and at the other end to the main sewage pipe with a 45° corner anti-clogging design. A three-stage septic tank is built underground, and the main sewage pipe is connected to the first stage of the three-stage septic tank. The transfer sewage tank is connected to the third-stage tank of the three-stage septic tank, and the water pump drives the sewage flow. The spherical microalgae self-mixing photobioreactor wall has its glass tubes connected to the intermediate sewage tank through the inlet pipe of the photobioreactor wall, and is driven to receive water by a centrifugal pump. The algae-water separator has a spiral glass tube extending into its interior for algae-water separation. An algae discharge pipe connects to the separator, and the first stage of the tertiary septic tank is connected to the separator via this pipe. An algae return pipe connects to the discharge pipe, with one end connected to the discharge pipe and the other end connected to the inlet pipe of the photobioreactor. A valve and flow meter on the return pipe regulate the inlet flow rate and algae return ratio. Most of the algae sludge produced by the separator is discharged into the tertiary septic tank via the discharge pipe, while the remaining portion is connected to the inlet pipe of the photobioreactor via the return pipe. This ensures that the algae cells in the photobioreactor maintain a relatively constant concentration for photosynthesis, achieving stable and efficient water purification. The effluent from the algae-water separator is reused for green space irrigation, fire emergency response, and sanitation cleaning.

[0007] Furthermore, the glass tube is an ultra-white double-tempered laminated glass tube with high light transmittance and high strength ionized interlayer film. The glass tube consists of two parts, including a circular tube body arranged in an upper and lower loop and several hollow spherical protrusions. The diameter of the protrusions is larger than the cross-sectional diameter of the circular tube body, and the center lines of the two coincide. In terms of shape, the gaps between the coiled glass tubes are filled with light-transmitting glass, forming a closed plane with the central axis of each glass tube, making it a complete wall.

[0008] The design, with a convex section diameter larger than the main circular tube, induces turbulence in the algal water as it flows through the convex section, breaking the laminar flow state and promoting thorough mixing of microalgae and wastewater, thereby improving the light energy utilization rate of microalgae. Simultaneously, the tightly arranged, meandering spherical circular tubes on the building's exterior facade extend the residence time of the microalgae's photobiochemical reaction, enhancing the degradation efficiency of pollutants through photosynthesis. This structure serves as both a functional component for wastewater treatment and enhances architectural aesthetics through its geometric form, achieving a fusion of functionality and architecture. The hollow spherical convex section achieves uniform light dispersion through curved surface refraction, ensuring that microalgae at different locations within the tube receive more balanced lighting conditions, effectively avoiding differences in treatment efficiency caused by uneven light distribution. This characteristic is particularly suitable for the complex scenarios of varying light intensity on different floors in high-rise buildings, providing an innovative solution for the design of photobioreactors in vertical spaces.

[0009] Furthermore, the algae-water separator includes the following structure: The upper end of the spiral tube is fixedly connected to the lower end of the meandering glass tube; The separator body includes a collection box, in which a separation ring plate is fixedly connected. The separation ring plate is fixedly connected to the inner bottom wall of the collection box. A frustum-shaped groove is formed in the middle of the separation ring plate. The upper bottom surface of the frustum-shaped groove is larger and the lower bottom surface is smaller. The algae discharge pipe is connected to the lower bottom surface of the frustum-shaped groove of the separator body and communicates with the frustum-shaped groove. The center line of the spiral tube coincides with the center line of the frustum-shaped groove. The lower end of the spiral tube does not contact the collection box. Water permeable holes for intercepting microalgae are opened on the separation ring plate. A cavity is left between the separation ring plate and the inner wall of the collection box. This cavity is set as a water passage pool. The water passage pool is connected to the water storage tank through a guide pipe.

[0010] The spiral tube guides the algae-water along a spiral path, creating a rotating flow pattern that gains radial kinetic energy under centrifugal force. As the algae-water enters the frustum-shaped groove, the inclined groove wall forces the water to flow downwards along the spiral trajectory, further enhancing the centrifugal separation effect. The uniformly distributed 40-60 μm permeable pores on the separation ring plate surface precisely trap microalgae with a diameter greater than 150 μm, allowing the treated water to pass through the permeable pores into the overflow tank, and finally flow into the storage tank via the guide pipe, achieving efficient separation of microalgae and water. The friction between the rotating algae-water and the inner bottom wall causes a secondary flow in the bottom fluid layer: due to the reduced flow velocity near the wall, the centrifugal force in this area is significantly weaker than at the center of the frustum, driving the bottom fluid to converge towards the central area. This flow characteristic results in a high-concentration accumulation zone of algal biomass at the bottom of the groove, which is then discharged centrally through the algae discharge pipe at the bottom. The frustum-shaped groove adopts a conical structure, wider at the top and narrower at the bottom. This, combined with the arrangement of the spiral tube's lower outlet axis parallel to the tangent of the separation ring plate's curved surface and spaced 10 cm apart, forms a gravity-guided microalgae settling path. The trapped microalgae slide down the groove wall to the bottom under gravity and flow back to the tertiary septic tank via the algae discharge pipe. A specially designed algae return pipe connects the middle of the algae discharge pipe to the upper end of the photobioreactor wall's inlet pipe, using a pump to achieve microalgae recycling, effectively reducing biomass loss and ensuring the sustainability of the system's processing capacity. The separator body adopts an underground buried design, perfectly fitting the spatial layout of high-rise buildings and avoiding the occupation of usable above-ground space. The overflow tank and storage tank are naturally connected by an inclined guide pipe (the elevation difference design creates gravity flow), enabling clean water transport without additional power, significantly reducing system energy consumption and aligning with the overall energy-saving design concept. The centerline of the spiral tube strictly coincides with the centerline of the frustum-shaped groove, ensuring a symmetrical distribution of the rotating water flow and preventing localized flow turbulence from affecting the separation effect. The separation ring plate is rigidly connected to the bottom wall of the collection tank, which significantly enhances the structural stability and can withstand water flow impact loads for a long time, ensuring the continuous reliability of the separation function.

[0011] Furthermore, an electric water valve is installed at the connection between the spiral tube and the glass tube, and a sensor is installed at the outlet of the glass tube to monitor water quality and algae density. The threshold is fed back to the controller, which adjusts the opening and closing of the electric water valve. The controller also participates in the control of the centrifugal pump on the inlet pipe of the photobioreactor wall.

[0012] The sensor monitors the algae density and water quality indicators at the outlet of the spherical tube in real time. When the algae density is lower than the set threshold (1×10), the water quality indicator will be activated. 6 If the algae concentration (cells / mL) exceeds 30 mg / L, the chemical oxygen demand (COD) exceeds 1.5 mg / L, or the total phosphorus exceeds 0.3 mg / L, the controller immediately shuts off the electric water valve, stopping algae-water separation and activating the water pump assembly on the inlet pipe of the photobioreactor wall for recirculation. This design allows the algae-water to remain within the circular tube for a longer period, enabling microalgae to fully utilize limited light or wait for suitable conditions, avoiding ineffective flow and improving the targeting and efficiency of wastewater purification.

[0013] Furthermore, the three-stage septic tank consists of a first-stage tank, a second-stage tank, and a third-stage tank. Sewage is transferred between adjacent tanks via water pumps. Each tank is equipped with a level gauge switch. When the liquid level is higher than a set high threshold, the water pump starts; when the high liquid level is lower than the set threshold, the water pump stops. When the level gauge switch is turned on, the corresponding water pump pumps the sewage from the lower tank to the upper tank.

[0014] Through a three-stage treatment process, wastewater undergoes gradual sedimentation and fermentation in each stage, achieving a stepwise removal of some pollutants. The first stage primarily traps large particulate impurities, the second stage further degrades organic matter, and the third stage completes deep purification. Compared to a single-stage septic tank, this significantly improves the thoroughness of wastewater pretreatment and reduces the load on subsequent microalgae purification stages. Each stage's level gauge switch is linked to its corresponding pump assembly, forming a "level-triggered automatic pumping" mechanism. When the water level in a lower stage exceeds a threshold, the level gauge switch activates, and the pump automatically starts, pumping wastewater to the next stage. When the water level falls below the threshold, the switch deactivates, and the pump stops. This design precisely controls the wastewater volume in each stage, preventing overloading of lower stages or continuous pumping from lower stages that are not full, ensuring a stable treatment rhythm.

[0015] Furthermore, a sewage branch pipe is connected to the pipeline between the third-stage tank of the septic tank and the intermediate sewage tank. The sewage branch pipe is connected to the rainy season sewage discharge pipe, and the sewage that the system cannot handle during the rainy season is discharged through a valve.

[0016] The T-junction pipe, controlled by a valve, allows for bidirectional switching between "routine treatment" and "emergency sewage discharge." During the non-rainy season and when the system is operating normally, sewage flows through the pump assembly and into the transfer sewage tank via the T-junction pipe, entering the subsequent microalgae purification stage. During the rainy season or when the system requires emergency drainage (e.g., due to a malfunction in the microalgae treatment stage), the rainy season sewage discharge valve is opened, allowing sewage to be directly discharged into the municipal pipeline through the T-junction pipe, preventing sewage from accumulating in the tertiary septic tank or transfer sewage tank. During periods of heavy rainfall in the rainy season, building sewage discharge may surge, potentially overloading the system if relying solely on routine treatment processes. The combined design of the T-junction pipe and the sewage discharge pipe provides an emergency diversion channel, quickly diverting excess sewage to the municipal pipeline network, preventing septic tank overflows and pipe blockages, and ensuring the safety and stability of the drainage system in high-rise buildings.

[0017] Furthermore, a biogas transmission pipe is connected to the third-stage tank cover of the septic tank, and the collected biogas is processed through a set procedure and used for energy replenishment inside the building.

[0018] The biogas (mainly methane) produced by the fermentation of sewage in the tertiary septic tank is collected through a biogas pipeline and transported to an integrated power generation unit. After dehydration, desulfurization, and purification, it is used as fuel to drive a generator to generate electricity. This process converts biogas that was originally directly emitted into electrical energy, realizing energy recovery in the sewage treatment process. This allows the device to not only have a purification function but also produce clean energy, improving the system's resource utilization efficiency and economic value.

[0019] The beneficial effects that can be achieved by adopting the above technologies are: This solution directs municipal wastewater through branch pipes into a main sewer system, where it undergoes a three-stage septic tank process to remove particulate organic matter. The wastewater then enters a spherical microalgae photobioreactor, where microalgae photosynthesis degrades pollutants, achieving resource recovery. The reactor employs a meandering glass tube and protruding joint design to enhance algae-water mixing and light energy utilization, extending the photosynthetic reaction time to improve purification efficiency. The treated effluent can be used for green space irrigation, fire fighting, and sanitation cleaning. The co-fermentation of algae slurry and fecal wastewater generates energy, supplementing building energy consumption. Attached Figure Description

[0020] Figure 1 This is a front view of the entire system; Figure 2 This is a side view of the entire system; Figure 3 This is a schematic diagram of the structure of a spherical microalgae self-mixing photobioreactor wall and a glass tube; Figure 4 yes Figure 3 This is a sectional view at point BB; Figure 5 This is a schematic diagram of the separator body.

[0021] 1. Spherical microalgae self-mixing photobioreactor wall; 2. Sewage branch pipe; 3. Sewage main pipe; 4. Three-stage septic tank; 5. Transfer sewage tank; 6. T-joint; 7. Inlet pipe of photobioreactor wall; 8. Glass tube; 81. Circular tube body; 82. Convex joint; 9. Glass curtain wall; 10. Spiral tube; 11. Algae-water separator; 12. Separation ring plate; 13. Groove; 14. Electric water valve; 15. Sensor; 16. Algae discharge pipe; 17. Water passage pool; 18. Diversion pipe; 19. Water storage tank; 20. Biogas gas delivery pipe; 21. Integrated power generation box; 22. Variable frequency water pump; 23. Sewage discharge pipe during the rainy season; 24. Interface pipe; 25. Algae return pipe. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, a high-rise building wastewater purification capacity system based on microalgae photobioreactor includes a spherical microalgae self-mixing photobioreactor wall 1, a wastewater collection pipe assembly, an algae-water separator 11, a three-stage septic tank 4, a transfer wastewater tank 5, a water storage tank 19, and an integrated power generation box 21.

[0024] The wastewater collection component includes the following structure: Multiple sewage branch pipes 2 are installed according to building drainage specifications. One end connects to the sewage outlet inside each floor of the building, and the other end uses a 45° corner anti-clogging design to connect to the main sewage pipe. Sewage generated by residents in the building flows into the main sewage pipe 3 through the corresponding sewage branch pipe 2, and then the main sewage pipe 3 guides the sewage downwards. The end of the sewage branch pipe 2 connected to the resident is higher than the end connected to the main sewage pipe 3. Based on this design, the sewage in the sewage branch pipe 2 flows naturally into the main sewage pipe 3 under the action of gravity. The main sewage pipe 3 is vertically set, and the sewage entering its cavity flows naturally downwards under the action of gravity.

[0025] 4-stage septic tank (see) Figure 2The sewage main pipe 3 is pre-buried in the building's basement. Sewage from the main pipe 3 flows from its lower end into the tertiary septic tank 4, which receives the sewage from the building's residents. The tertiary septic tank 4 consists of three septic tanks (a first-stage tank, a second-stage tank, and a third-stage tank), with volumes of 50, 100, and 150 cubic meters respectively. Sewage is transferred between adjacent tanks via a pump assembly. The lower end of the main sewage pipe 3 is located in the first-stage tank. The third-stage tank is connected to the intermediate sewage tank 5 (located in the basement), and sewage is transferred via another pump assembly. The outlet of the pump assembly between the third-stage tank and the intermediate sewage tank 5 is connected to a sewage branch pipe. This branch pipe is a T-junction; one port of the T-junction is connected to the outlet of the pump assembly, one of the other two ports is connected to the intermediate sewage tank 5, and the remaining port is connected to the rainy season drainage pipe 23. During the rainy season, the sewage pipe 23 connects to the municipal pipeline. By opening the valve on the rainy season sewage pipe 23 and closing the valve on the pipeline connected to the intermediate sewage tank 5, the sewage from the septic tank can be discharged to the municipal pipeline through the cooperation of the pump assembly. During normal use, the valve on the rainy season sewage pipe 23 is closed, and the valve on the pipeline to the intermediate sewage tank 5 is open, allowing sewage to enter the intermediate sewage tank 5. Each stage tank is equipped with a level gauge switch. When the water level in the lower stage tank exceeds a set threshold, the level gauge switch is activated, and the corresponding pump assembly pumps the sewage from the lower stage tank to the upper stage tank. When the sewage in the third stage tank exceeds the set threshold, the corresponding pump assembly pumps the sewage from the third stage tank to the intermediate sewage tank 5.

[0026] The inlet pipe 7 of the photobioreactor wall is installed on the exterior wall of the building. Its lower end is connected to and communicates with the intermediate wastewater tank 5 and the algae return pipe 25. A variable frequency pump 22 (centrifugal pump) installed on the inlet pipe 7 pumps wastewater from the intermediate wastewater tank 5 to the starting port of the spherical microalgae self-mixing photobioreactor wall 1. A level gauge is installed in the intermediate wastewater tank 5. A controller located at a remote end receives the level signal from the level gauge, thereby controlling the speed of the variable frequency pump 22. The controller controls the variable frequency pump based on the water level in the intermediate tank. When the water level is higher than the high threshold, the controller controls the variable frequency pump to start. The higher the water level is above the high threshold, the faster the controller controls the variable frequency pump to rotate (up to 70% of the rated speed). When the water level in the intermediate wastewater tank 5 is lower than the set low threshold, the controller controls the variable frequency pump to stop.

[0027] The spherical microalgae self-mixing photobioreactor wall 1 includes the following structure: The glass tube 8 is a roundabout glass tube made of ultra-white double-tempered laminated glass with an ionomer interlayer film. The glass tube 8 consists of two parts: a roundabout circular tube body 81 and several hollow spherical protrusions 82 set on the circular tube body 81 (see...). Figure 3The top of the circular tube body 81 is located at the top of the building. Its top port serves as the starting point and is connected to the top port of the photobioreactor wall water inlet pipe 7 via a pipeline, sealed with a rubber ring. The bottom of the circular tube body 81 is connected to the algae-water separator. A spherical protrusion 82 is arranged along the length of the circular tube body 81. Its diameter is larger than the end face diameter of the circular tube body 81 (e.g., 1.5 times), and their centerlines coincide. This allows the algae-water inside the circular tube body 81 to generate turbulence at the protrusion 82. The protrusion 82 allows the algae-water to stay in the glass tube 8 for a longer time, allowing it to receive more light. The glass curtain wall 9 on the building is connected to the circular tube body 81 and the protrusion 82 (glass structure adhesive bonding). The centerlines of both the circular tube body 81 and the protrusion 82 are located in the plane of the glass curtain wall 9 (see...). Figure 4 ).

[0028] The algae-water separator includes the following components: Spiral tube 10 (see) Figure 5 The upper end is fixedly connected and communicates with the lower end of the round tube body 81 arranged in a roundabout manner. The lower end is located in the groove 13 described below, and the lower end of the spiral tube 10 only extends into the algae water separator 11 for about 10 cm. Its tube outlet axis is parallel to the tangent of the groove surface 13.

[0029] An algae separator 11 is installed in a basement. It includes a collection box (hollow box structure) with a separation ring plate 12 fixedly connected to its cavity. The separation ring plate 12 is fixedly connected to the inner bottom wall of the collection box. A frustum-shaped groove 13 is formed in the center of the separation ring plate 12, with a larger upper surface and a smaller lower surface. The centerline of the spiral tube 10 coincides with the centerline of the frustum-shaped groove. A cavity is left between the outer surface of the separation ring plate 12 and the inner wall of the collection box, which serves as a water passage tank 17. Water-permeable holes with a diameter of 40-60 micrometers are provided on the side of the separation ring plate 12, which can be used to filter microalgae (colony microalgae larger than 150 micrometers). The design of the water-permeable holes connects the groove 13 to the water passage tank 17. The lower end of the aforementioned spiral tube 10 is located in the groove 13. When the algae water flows into the flow channel of the spiral tube 10 from the main body 81 of the circular tube, the algae water rotates rapidly along the spiral tube 10 under the action of the shape of the spiral tube 10, and flows out of the spiral tube 10 from the lower end along its axis. The algae water continues to make circular motion on the side wall of the separation ring plate 12. Due to the frustum shape of the groove 13, the algae water moves along the surface of the groove and is subjected to centrifugal force at the water permeable hole. The treated water is discharged into the water passing tank 17 through the water permeable hole. Due to the design of the pore size of the water permeable hole, most of the microalgae remain in the groove 13, and only a small part of the microalgae enters the water passing tank 17.

[0030] An electric water valve 14 is installed at the top of the spiral tube 10, which is controlled by the controller signal to open and close. A multi-sensor 15 is also installed at the spiral tube 10, mainly consisting of an algae density sensor and a water quality sensor. The concentration sensor is located inside the spiral tube 10 to monitor algae density and transmit the data to the controller. The water quality sensor is located outside the spiral tube 10 and mainly monitors the concentrations of organic matter, nitrogen, and phosphorus in the water and transmits the data to the controller. When the concentration exceeds a set threshold, the controller closes the electric water valve 14; or when the microalgae concentration is below the set threshold, the controller closes the electric water valve 14. After the electric water valve 14 is closed, the pump assembly on the inlet pipe of the photobioreactor wall simultaneously stops operating, allowing the algae-infused water to remain in the main body of the circular tube 81 for a longer period. The system does not discharge externally, and the microalgae provide more sustained treatment of wastewater. After the controller closes the electric water valve 14, it opens the valve on the rainy season drain pipe 23 on the three-way pipe to discharge wastewater that cannot be absorbed due to system instability or changes in the external environment. In other data scenarios, the controller will open the electric water valve 14, and the system will normally treat the wastewater through microalgae.

[0031] The algae discharge pipe 16 is fixed at one end to the lower end of the separation ring plate 12 and connected to the lower end of the groove 13. The other end is connected to the first-stage tank in the three-stage septic tank 4. The algae slurry in the algae discharge pipe 16 flows freely into the first-stage tank in the three-stage septic tank 4 by gravity. An algae return pipe 25 is also connected to the middle of the pipe, and a valve and flow meter are provided to regulate the influent flow rate and algae return ratio. The other end of the algae return pipe 25 is connected to the inlet pipe 7 of the photobioreactor wall. The connection position of the algae return pipe 25 is located at the lower end of the variable frequency water pump 22 on the inlet pipe 7 of the photobioreactor wall. The variable frequency water pump 22 on the inlet pipe 7 of the photobioreactor wall pumps back part of the algae slurry for recycling. That is, the algae-water separator is connected to the three-stage septic tank through the algae discharge pipe to discharge most of the remaining algae slurry into the three-stage septic tank. The other part will be connected to the inlet pipe of the photobioreactor wall through the algae return pipe to ensure that the algae cells in the photobioreactor wall are photosynthesizing at a relatively constant concentration.

[0032] The outer surface of the algae separator 11 is connected to and communicates with the water storage tank 19 (located in the basement) via a guide pipe 18. Since the end of the guide pipe 18 connected to the algae separator 11 is higher than the end connected to the water storage tank 19, the treated water in the overflow tank 17 can naturally flow into the water storage tank 19 through the guide pipe 18. The water storage tank 19 stores the treated water for daily use, such as municipal watering and vegetation. An interface pipe 24 (see...) is installed on the top of the water storage tank 19. Figure 2 The top of the interface pipe 24 is located above the ground, which facilitates the quick connection between the corresponding interface of the municipal flower and vegetation water supply equipment and the water storage tank 19, so that the sewage in the water storage tank 19 can be extracted and used in a timely manner.

[0033] The first-stage tank of the tertiary septic tank 4 is connected to a biogas venting pipe 20. The other end of the biogas venting pipe 20 is connected to an integrated generator box 21. The integrated generator box 21 integrates dehydration, desulfurization, and purification components. The generator box uses the purified biogas as fuel to drive a generator for grid connection. A one-way valve is installed on the biogas venting pipe 20 to prevent backflow of biogas. In addition, the biogas venting pipe 20 is also equipped with sensors (connected to the controller) for monitoring biogas pressure and other safety aspects, facilitating the timely detection of potential hazards. The third-stage tank of the tertiary septic tank 4 is used for replenishing and initially introducing algae parent material. Algae parent material can be introduced by opening the cover of the third-stage tank. Because the entire system achieves algae recycling and reuse, the treatment cycle is relatively long, generally requiring replenishment of microalgae parent material every 10-20 days.

[0034] Device operation process: When the microalgae concentration (2000 mg / L) in the main body of the circular pipe 81 is high and there is no rainwater, the controller operates normally. Wastewater generated by users is discharged into a three-stage septic tank, and after passing through multiple pump assemblies, it is discharged from the transfer wastewater tank into the top of the glass tube 8. The algae-infused water in the glass tube is treated by sunlight. After the algae-infused water flows out of the main body of the circular pipe 81, the microalgae slurry remains in the groove and re-enters the three-stage septic tank through the algae discharge pipe 16 or enters the algae return pipe 25. The treated water then enters the storage tank 19 through the guide pipe 18. Relevant personnel replenish the microalgae parent material approximately every 10 days.

[0035] When the microalgae concentration in the main body 81 of the circular tube is low, or when there is rainwater, the controller stops the water pump assembly on the inlet pipe of the photobioreactor wall, and closes the electric water valve at the bottom of the main body 81 of the circular tube and opens the valve on the sewage pipe during the rainy season to discharge excess sewage into the municipal sewage branch pipe; when the microalgae concentration in the main body 81 of the circular tube is high and there is no rainwater, the controller restarts the normal operation of the device.

[0036] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A building wastewater purification and production capacity system based on microalgae photobioreactor, characterized in that, Includes the following constructions: Multiple sewage pipes are connected at one end to the sewage outlet inside each floor of the building, and at the other end to the main sewage pipe with a 45° corner anti-clogging design. A three-stage septic tank is built underground, and the main sewage pipe is connected to the first stage of the three-stage septic tank. The transfer sewage tank is connected to the third-stage tank of the three-stage septic tank, and the water pump drives the sewage flow. The spherical microalgae self-mixing photobioreactor wall has its glass tubes connected to the intermediate sewage tank through the inlet pipe of the photobioreactor wall, and is driven to receive water by a centrifugal pump. The algae-water separator has a spiral glass tube extending into its interior for algae-water separation. An algae discharge pipe connects to the separator, and the first stage of the tertiary septic tank is connected to the separator via this pipe. An algae return pipe connects to the discharge pipe, with one end connected to the discharge pipe and the other end connected to the inlet pipe of the photobioreactor. A valve and flow meter on the return pipe regulate the inlet flow rate and algae return ratio. Most of the algae sludge produced by the separator is discharged into the tertiary septic tank via the discharge pipe, while the remaining portion is connected to the inlet pipe of the photobioreactor via the return pipe. This ensures that the algae cells in the photobioreactor maintain a relatively constant concentration for photosynthesis, achieving stable and efficient water purification. The effluent from the algae-water separator is reused for green space irrigation, fire emergency response, and sanitation cleaning.

2. The building wastewater purification and production capacity system based on microalgae photobioreactor according to claim 1, characterized in that, The glass tube is an ultra-white double-tempered laminated glass tube with high light transmittance and high strength ionized interlayer film. The glass tube consists of two parts, including a circular tube body arranged in an upper and lower loop and several hollow spherical protrusions. The diameter of the protrusions is larger than the cross-sectional diameter of the circular tube body, and the center lines of the two coincide. In terms of shape, the coiled glass tubes are separated by gaps with light-transmitting glass, forming a closed plane with the central axis of each glass tube, making it a complete wall.

3. The building wastewater purification capacity system based on microalgae photobioreactor according to claim 2, characterized in that, The algae-water separator includes the following structure: The upper end of the spiral tube is fixedly connected to the lower end of the meandering glass tube; The separator body includes a collection box, in which a separation ring plate is fixedly connected. The separation ring plate is fixedly connected to the inner bottom wall of the collection box. A frustum-shaped groove is formed in the middle of the separation ring plate. The upper bottom surface of the frustum-shaped groove is larger and the lower bottom surface is smaller. The algae discharge pipe is connected to the lower bottom surface of the frustum-shaped groove of the separator body and communicates with the frustum-shaped groove. The center line of the spiral tube coincides with the center line of the frustum-shaped groove. The lower end of the spiral tube does not contact the collection box. Water permeable holes for intercepting microalgae are opened on the separation ring plate. A cavity is left between the separation ring plate and the inner wall of the collection box. This cavity is set as a water passage pool. The water passage pool is connected to the water storage tank through a guide pipe.

4. The building wastewater purification capacity system based on microalgae photobioreactor according to claim 3, characterized in that, An electric water valve is installed at the connection between the spiral tube and the glass tube, and a sensor is installed at the outlet of the glass tube to monitor water quality and algae density. The threshold is fed back to the controller, which adjusts the opening and closing of the electric water valve. The controller also participates in the control of the centrifugal pump on the inlet pipe of the photobioreactor wall.

5. A building wastewater purification capacity system based on microalgae photobioreactor according to claim 4, characterized in that, The three-stage septic tank consists of a first-stage tank, a second-stage tank, and a third-stage tank. Sewage is transferred between adjacent tanks via water pumps. Each tank is equipped with a level gauge switch. When the liquid level is higher than a set high threshold, the water pump starts; when the high liquid level is lower than the set threshold, the water pump stops. When the level gauge switch is turned on, the corresponding water pump pumps the sewage from the lower tank to the upper tank.

6. A building wastewater purification capacity system based on microalgae photobioreactor according to claim 5, characterized in that, A sewage branch pipe is connected to the pipeline between the third-stage tank of the septic tank and the intermediate sewage tank. The sewage branch pipe is connected to the rainy season sewage discharge pipe, and the sewage that the system cannot handle during the rainy season is discharged through the valve.

7. A building wastewater purification capacity system based on microalgae photobioreactors according to claim 6, characterized in that, The third-stage tank cover of the septic tank is connected to a biogas transmission pipe. The collected biogas is processed through a set procedure and then used for energy replenishment inside the building.

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