Photo-biological circulating fixed bed reaction system and method for purifying urine based on microalgae

Abstract

The invention belongs to the technical field of domestic sewage treatment, and particularly relates to a photobiological circulating fixed bed reaction system and method for purifying urine based on microalgae, and the photobiological circulating fixed bed reaction system comprises a circulating fixed bed reactor, a lighting system, an aeration system and a liquid driving system, the photo-biological circulating fixed bed reaction system consists of a circulating fixed bed reactor, a lighting system, an aeration system and a liquid driving system; clinoptilolite is used as a filler of the fixed bed area, the concentration of ammonia nitrogen in the urine can be greatly reduced in the cyclic adsorption process, so that a favorable environment is provided for growth of microalgae, the concentration of the ammonia nitrogen in the treated urine is reduced to a quite low level, and under the action of concentration gradient pressure, the concentration of the ammonia nitrogen in the urine is reduced to a quite high level. The clinoptilolite filler loaded with ammonia nitrogen can desorb ammonia nitrogen into urine, a nitrogen source is provided for growth of microalgae, and meanwhile regeneration of the clinoptilolite filler is achieved in the process.

Description

Technical Field

[0001] The invention belongs to the technical field of domestic sewage treatment, and specifically is a photobiological cycle fixed bed reaction system and method for purifying urine based on microalgae. Background Art

[0002] Urine is a liquid metabolic waste discharged by the human body. It provides a large amount of nitrogen and phosphorus in urban domestic sewage with a relatively small volume. At present, the main methods for recovering nitrogen and phosphorus in urine include evaporation, ammonia stripping, membrane separation, and struvite precipitation. These methods have certain limitations, such as high energy consumption, consumption of chemical agents, and high equipment investment. Microalgae are a type of microorganism that contains chlorophyll and can perform photosynthesis. They have the characteristics of many varieties, high carbon fixation capacity, and strong adaptability. Using microalgae to treat urine can achieve efficient recovery of nitrogen and phosphorus elements, with the advantages of low operating costs, no secondary pollution, and low carbon emissions. The harvested microalgae biomass can be processed into high-value products such as biofuels, aquaculture feed, and health products, thereby providing further economic benefits.

[0003] However, the above-mentioned technologies often have the following defects: there are still certain obstacles to the treatment of urine with microalgae. First, the hydrolysis of high concentrations of ammonia nitrogen in urine will inhibit the growth of microalgae. This inhibition is mainly reflected in genetic information, photosynthesis, nutritional metabolic pathways, etc., slowing down the growth rate of microalgae and even apoptosis. Traditional urine pretreatment methods mainly include dilution and nitrification, which means that a large amount of water resources need to be consumed and a separate processing unit needs to be added, which increases the operating cost of the system. Secondly, the photobioreactor is the core device for microalgae cultivation, and the chromaticity of urine and the high biomass shielding in the later stage of cultivation reduce the light energy obtained by the microalgae inside the reactor, which makes it impossible to further increase the biomass of microalgae in the later stage of cultivation. Therefore, in the application of using microalgae to treat urine on a large scale, there are problems such as high concentration of ammonia nitrogen inhibition and poor light receiving ability of microalgae in the photobioreactor. For this reason, the present invention provides a photobiological cycle fixed bed reaction system and method based on microalgae to purify urine. Summary of the invention

[0004] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0005] The technical solution adopted by the present invention to solve the technical problem is: the photobiological cycle fixed bed reaction system based on microalgae for purifying urine of the present invention comprises a cycle fixed bed reactor, a lighting system, an aeration system and a liquid drive system; the photobiological cycle fixed bed reaction system comprises a cycle fixed bed reactor, a lighting system, an aeration system and a liquid drive system;

[0006] The circulating fixed bed reactor comprises an outer cylinder of the reactor and an inner cylinder of the reactor, both of which are transparent hollow structures and have the same height, and the inner cylinder of the reactor is coaxially fixed inside the outer cylinder of the reactor;

[0007] A reactor bottom plate, arranged at the bottom of the reactor outer cylinder and the reactor inner cylinder;

[0008] A reactor top cover, arranged on the top of the reactor outer cylinder and the reactor inner cylinder;

[0009] The first baffle, the second baffle, the third baffle, and the fourth baffle are all made of transparent materials, have the same height as the outer cylinder of the reactor and the inner cylinder of the reactor, and are vertically arranged in the space between the outer cylinder of the reactor and the inner cylinder of the reactor, dividing the space into four chambers of equal volume, namely, the inflow zone, the first aeration zone, the second aeration zone, and the outflow zone. The first baffle, the second baffle, and the third baffle are provided with circular holes to ensure the flow of reactants between the chambers;

[0010] Clinoptilolite filler is filled inside the cylinder of the reactor, which is called the fixed bed zone. The particle size of the clinoptilolite filler is 1-3 mm, and the filling volume accounts for 80-90% of the volume of the fixed bed zone.

[0011] The inner cylinder of the reactor is cut off at the upper part of the inflow zone to ensure the overflow of the effluent, the upper interface of the cutoff is flush with the height of the inner cylinder of the reactor, and the lower interface of the cutoff is higher than the height of the fixed bed zone;

[0012] The first baffle hole is arranged at the lower part, the second baffle hole is arranged at the upper part and the upper limit of the hole is not higher than the lower interface of the cutoff of the inner cylinder of the reactor, and the third baffle hole is arranged at the lower part;

[0013] A water inlet, disposed on the top cover of the reactor, for injecting the reactants and inoculating the microalgae;

[0014] An exhaust valve, disposed on the reactor top cover, for exhausting excess gas in the circulating fixed bed reactor;

[0015] A drain port, disposed at the bottom of the outer cylinder of the reactor, for draining the reactants in the circulating fixed bed reactor;

[0016] The reactor base is arranged below the reactor bottom plate and is used to support the circulating fixed bed reactor body.

[0017] Preferably, the lighting system comprises an arc-shaped light guide plate, which is arranged outside the circulating fixed bed reactor and is used to provide light for the cultured microalgae;

[0018] The LED light strip is attached to the upper thickness surface of the curved light guide plate, and the spectrum color provided is blue light;

[0019] The arc surface of the arc-shaped light guide plate closer to the circulating fixed bed reactor is used as a light emitting surface, and the arc surface farther from the circulating fixed bed reactor and other thickness surfaces are attached with reflective films as reflective surfaces.

[0020] Preferably, the aeration system comprises an aerator, and the aerator provides air mixed gas to the circulating fixed bed reactor;

[0021] A gas delivery main pipe connected to the aerator and used for delivering the air mixture;

[0022] A manual gas pipe switch valve is provided on the gas delivery main pipe to control the delivery of the air mixture;

[0023] A gas delivery branch pipe passes through the reactor top cover and extends into the first aeration zone and the second aeration zone of the circulating fixed bed reactor;

[0024] A gas three-way joint connected to the gas delivery main pipe and the gas delivery branch pipe;

[0025] A gas flow meter, arranged on the gas delivery branch pipe, for controlling the aeration flow;

[0026] The microporous aeration head is arranged at the end of the gas delivery branch pipe and is used to generate microporous bubbles.

[0027] Preferably, the liquid drive system comprises a peristaltic pump, which provides a power source for the circulation of the reactants;

[0028] The outflow branch pipe and the inflow branch pipe are connected to the peristaltic pump;

[0029] A fixed bed zone liquid delivery branch pipe, used for transferring the reactants in the fixed bed zone, passes through the reactor top cover, and extends to the bottom of the fixed bed zone;

[0030] An outflow zone liquid delivery branch pipe, used for transferring the reactants in the outflow zone, passes through the reactor top cover, and extends to the bottom of the outflow zone;

[0031] An inflow zone liquid delivery branch pipe, used for transferring the reactants in the inflow zone, passes through the reactor top cover, and extends to the bottom of the inflow zone;

[0032] A water pipe quick-connect straight-through is arranged at the top of the liquid delivery branch pipe in the fixed bed area, the liquid delivery branch pipe in the outflow area, and the liquid delivery branch pipe in the inflow area to achieve connection with the outflow branch pipe and the inflow branch pipe;

[0033] A manual water pipe switch valve is arranged on the liquid delivery branch pipe of the fixed bed area, the liquid delivery branch pipe of the outflow area, and the liquid delivery branch pipe of the inflow area to control the delivery of the reactants.

[0034] Preferably, an annular groove is provided on the side wall of the microporous aeration head, a slider is slidably connected to the inner wall of the annular groove, a connecting plate is fixedly connected to the side of the slider away from the annular groove, a brush for cleaning the micropores is fixedly connected to the side of the connecting plate close to the microporous aeration head, a rotatable connecting shaft is vertically arranged in the microporous aeration head, a group of driving blades are fixedly connected to the side wall of the connecting shaft, a fixing rod is fixedly connected to the side wall of the connecting shaft corresponding to the micropore, and a first magnetic block magnetically attracted to the connecting plate is fixedly connected to the side of the fixing rod away from the connecting shaft.

[0035] Preferably, the microporous aeration head is sealingly and slidably connected to the side wall of the gas delivery branch pipe, a pair of connecting rods are fixedly connected to the bottom surface of the gas delivery branch pipe, a disc is fixedly connected to the bottom surface of the connecting rods, the top surface of the connecting shaft is rotatably connected to the disc, a ring is slidably connected to the side wall of the disc, a group of first springs are fixedly connected between the top surface of the ring and the inner wall of the top surface of the microporous aeration head, a second magnetic block is fixedly connected to the top surface of the driving blade, a group of magnetic sheets corresponding to the second magnetic block are fixedly connected to the bottom surface of the disc, and the second magnetic block and the magnetic sheets are arranged to repel each other.

[0036] Preferably, a hollow groove is formed on the microporous aeration head, a sealing plate for sealing the micropores is sealingly and slidably connected in the hollow groove, through holes corresponding to the micropores are formed on the sealing plate, an air inlet hole connected to the hollow groove is formed on the inner wall of the microporous aeration head, the air inlet hole is located on the bottom surface of the sealing plate, an air outlet hole connected to the hollow groove is formed on the outer wall of the microporous aeration head, the air outlet hole is located on the top surface of the sealing plate, and a second spring is fixedly connected between the top surface of the sealing plate and the inner wall of the hollow groove.

[0037] A photobiological cycle fixed bed reaction method for purifying urine based on microalgae, the method adopts the above-mentioned photobiological cycle fixed bed reaction system for purifying urine based on microalgae, and the method comprises the following steps:

[0038] S1: Introduce urine into the circulating fixed bed reactor through the water inlet, connect the outflow branch pipe with the fixed bed liquid delivery branch pipe, connect the inflow branch pipe with the outflow zone liquid delivery branch pipe, start the peristaltic pump, and circulate the urine in the circulating fixed bed reactor until saturation, and then turn off the peristaltic pump;

[0039] S2: Connect the outflow branch pipe to the liquid delivery branch pipe in the inflow area, connect the inflow branch pipe to the liquid delivery branch pipe in the fixed bed area, start the peristaltic pump, discharge the residual urine in the fixed bed area into the inflow area, and then turn off the peristaltic pump;

[0040] S3: inoculating microalgae into the circulating fixed bed reactor through the water inlet, connecting the outflow branch pipe with the inflow area liquid delivery branch pipe, connecting the inflow branch pipe with the outflow area liquid delivery branch pipe, and starting the aerator and the peristaltic pump for circulating cultivation of microalgae;

[0041] S4: The lighting effects of day and night are differentiated by turning on and off the LED light strips. The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches stability, the aerator and peristaltic pump are turned off.

[0042] S5: The urine and microalgae mixture is discharged through the drain port, and after the algae-water separation, the separated urine is collected and introduced into the circulating fixed bed reactor through the water inlet, and the microalgae are inoculated through the water inlet;

[0043] S6: During the day, the outflow branch pipe is connected to the liquid delivery branch pipe of the inflow area, the inflow branch pipe is connected to the liquid delivery branch pipe of the outflow area, and the aerator and the peristaltic pump are turned on to perform suspension culture of microalgae;

[0044] S7: At night, turn off the aerator and the peristaltic pump, connect the outflow branch pipe to the fixed bed liquid delivery branch pipe, connect the inflow branch pipe to the outflow zone liquid delivery branch pipe, and then turn on the peristaltic pump to regenerate the clinoptilolite filler with the urine and microalgae mixture, and realize the zeolite-based microalgae circulation culture;

[0045] S8: The lighting effects of day and night are differentiated by turning on and off the LED light strips. The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches stability, the process ends, the aerator and peristaltic pump are turned off, and the urine and microalgae mixture is discharged from the drain port for algae-water separation.

[0046] The beneficial effects of the present invention are as follows:

[0047] 1. The high concentration of ammonia nitrogen in the urine of the present invention has an inhibitory effect on the growth of microalgae. Clinoptilolite is a silicate mineral with a high ion exchange capacity and good affinity for ammonium ions. By using clinoptilolite as a filler in the fixed bed area, the concentration of ammonia nitrogen in urine can be greatly reduced during the cyclic adsorption process, thereby providing a favorable environment for the growth of microalgae. After treatment, the ammonia nitrogen concentration in urine is reduced to a very low level. Under the action of concentration gradient pressure, the clinoptilolite filler loaded with ammonia nitrogen can desorb the ammonia nitrogen into urine, providing a nitrogen source for the growth of microalgae. At the same time, this process also realizes the regeneration of the clinoptilolite filler.

[0048] 2. In the present invention, the chromaticity of urine and the high-concentration biomass of microalgae will affect the illumination inside the reactor. The fixed bed area that does not require illumination is set at the center of the reactor, thereby reducing the impact of insufficient internal irradiation. In addition, by independently setting the fixed bed area, it is beneficial to mix and separate the clinoptilolite filler and the reactants. An inflow area, a first aeration area, a second aeration area, and an outflow area are set outside the fixed bed area. Microalgae are cultured in the above four areas, shortening the light path and improving the photosynthetic efficiency. In addition, various functional units are integrated in a reactor body, which reduces the footprint while reducing the difficulty of operation and management. By switching the liquid pipeline, the conversion of multiple operation modes can be achieved, which has great flexibility.

[0049] 3. The microalgae light-harvesting pigments in the present invention are more sensitive to blue light. Blue light has a short wavelength and higher energy, and has stronger penetration in water. The use of an arc-shaped light guide plate that emits blue light as a light source improves the photosynthesis efficiency of microalgae, and is also beneficial to the production of microalgae biomass and the accumulation of intracellular components, which is beneficial to the subsequent development of microalgae resources.

[0050] 4. When the gas delivery branch pipe in the present invention injects gas into the microporous aeration head, the airflow drives the driving blade to rotate, and the driving blade drives the connecting shaft to rotate, thereby driving the first magnetic block to rotate. At this time, the connecting plate magnetically attracted to the first magnetic block will also rotate, and the bristles will clear and clean the micropores on the microporous aeration head to solve the problem of blockage of the micropores due to long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described below in conjunction with the accompanying drawings.

[0052] Figure 1 It is a schematic diagram of the structure of the photobiological cycle fixed bed reaction system in the present invention;

[0053] Figure 2 It is a schematic diagram of the structure of the circulating fixed bed reactor in the present invention;

[0054] Figure 3 is a top view of a circulating fixed bed reactor in the present invention;

[0055] Figure 4 It is a schematic diagram of the structure of the inflow zone of the circulating fixed bed reactor in the present invention;

[0056] Figure 5 It is a schematic diagram of the structure of the first aeration zone of the circulating fixed bed reactor in the present invention;

[0057] Figure 6 It is a schematic diagram of the structure of the second aeration zone of the circulating fixed bed reactor in the present invention;

[0058] Figure 7 It is a schematic diagram of the structure of the outflow zone of the circulating fixed bed reactor in the present invention;

[0059] Figure 8 It is a schematic diagram of the structure of the fixed bed zone of the circulating fixed bed reactor in the present invention;

[0060] Fig. 9 It is a schematic diagram of the structure of the gas delivery branch pipe and the microporous aeration head in the present invention;

[0061] Fig.10 It is a schematic diagram of the internal structure of the microporous aeration head of the present invention;

[0062] Fig.11 yes Fig.10 A magnified image of point A;

[0063] Fig.12 yes Fig.10 The enlarged view of point B;

[0064] Fig.13 It is a flow chart of the method in the present invention.

[0065] In the figure: 1, aerator; 2, gas delivery main pipe; 3, manual switch valve of gas pipe; 4, gas pipe three-way joint; 5, gas flow meter; 6, gas delivery branch pipe; 7, microporous aeration head; 8, first baffle; 9, second baffle; 10, third baffle; 11, fourth baffle; 12, reactor top cover; 13, reactor outer cylinder; 14, reactor inner cylinder; 15, clinoptilolite filler; 16, water inlet; 17, exhaust valve; 18, drain outlet; 19, reactor base; 20, reactor bottom plate; 21, peristaltic pump; 22, Outflow branch pipe; 23, inflow branch pipe; 24, water pipe quick-connect straight-through; 25, water pipe manual switch valve; 26, fixed bed area liquid delivery branch pipe; 27, outflow area liquid delivery branch pipe; 28, inflow area liquid delivery branch pipe; 29, arc-shaped light guide plate; 30, LED light strip; 31, connecting shaft; 32, driving blade; 33, fixing rod; 34, first magnetic block; 35, connecting plate; 36, connecting rod; 37, disc; 38, ring; 39, magnetic sheet; 40, second magnetic block; 41, hollow groove; 42, sealing plate; 43, slider DETAILED DESCRIPTION

[0066] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0067] Embodiment 1: Figures 1 to 8 As shown, the photobiological circulating fixed bed reaction system for purifying urine based on microalgae according to the embodiment of the present invention is composed of a circulating fixed bed reactor, a lighting system, an aeration system and a liquid driving system.

[0068] The circulating fixed bed reactor comprises an outer cylinder 13 and an inner cylinder 14, both of which are transparent hollow structures. The inner cylinder 14 is coaxially fixed in the outer cylinder 13; a reactor bottom plate 20 is arranged at the bottom of the outer cylinder 13 and the inner cylinder 14; a reactor top cover 12 is arranged at the top of the outer cylinder 13 and the inner cylinder 14; a first baffle 8, a second baffle 9, a third baffle 10, and a fourth baffle 11 are vertically arranged in the space between the outer cylinder 13 and the inner cylinder 14, dividing the space into four chambers of equal volume, namely, an inflow zone, a first aeration zone, a second aeration zone, and an outflow zone; a clinoptilolite filler 15 is filled in the inner cylinder 14 of the reactor, which is called a fixed bed zone.

[0069] The diameter of the reactor outer cylinder 13 is 120 mm, the diameter of the reactor inner cylinder 14 is 60 mm, the heights of the reactor outer cylinder 13 and the reactor inner cylinder 14 are both set to 160 mm, and the reactor inner cylinder 14 is cut off at the upper part of the inflow zone to ensure water overflow, and the cutoff height is set to 10 mm.

[0070] The height of the first baffle 8, the second baffle 9, the third baffle 10, and the fourth baffle 11 is set to 160 mm. Figure 4 , 5 As shown in , 6, circular holes are set on the first baffle 8, the second baffle 9, and the third baffle 10 to ensure the flow of reactants between the chambers. The holes of the first baffle 8 are set at the lower part of the baffle, the holes of the second baffle 9 are set at the upper part of the baffle and the upper limit of the holes is not higher than the lower interface of the cylindrical truncation in the reactor, and the holes of the third baffle 10 are set at the lower part of the baffle, and the diameter of the holes is set to 10 mm.

[0071] The materials used for the reactor outer cylinder 13, the reactor inner cylinder 14, the reactor bottom plate 20, the reactor top cover 12, the first baffle 8, the second baffle 9, the third baffle 10 and the fourth baffle 11 are all polymethyl methacrylate.

[0072] The particle size of the clinoptilolite filler 15 is 1-3 mm, and the filling volume accounts for 80% of the volume of the fixed bed area.

[0073] The circulating fixed bed reactor also includes a water inlet 16, which is arranged on the reactor top cover 12 and is used to inject reactants and inoculate microalgae; an exhaust valve 17, which is arranged on the reactor top cover 12 and is used to discharge excess gas in the circulating fixed bed reactor; a drain port 18, which is arranged at the bottom of the reactor outer cylinder 13 and is used to empty the reactants in the circulating fixed bed reactor; a reactor base 19, which is arranged under the reactor bottom plate 20 and is used to support the main body of the circulating fixed bed reactor.

[0074] The lighting system consists of an arc-shaped light guide plate 29 and an LED light strip 30. The two arc-shaped light guide plates 29 are located outside the circulating fixed bed reactor. The LED light strip 30 is attached to the thickness surface above the arc-shaped light guide plate 29. The arc-shaped surface of the arc-shaped light guide plate 29 closer to the circulating fixed bed reactor serves as the light emitting surface, and the arc-shaped surface farther from the circulating fixed bed reactor and other thickness surfaces are attached with reflective film as reflective surfaces. The spectral color provided by the LED light strip 30 is blue light (450-485nm).

[0075] The aeration system consists of an aerator 1, a gas delivery main pipe 2, a manual air pipe switch valve 3, a gas three-way joint 4, a gas flowmeter 5, a gas delivery branch pipe 6, and a microporous aeration head 7. The aerator 1 provides an air mixture (the volume fraction of CO2 is 5%), and the output air mixture enters the gas three-way joint 4 along the gas delivery main pipe 2 and is then connected to two gas delivery branches 6. The two gas delivery branches 6 pass through the reactor top cover 12 and are respectively connected to the first aeration zone and the second aeration zone of the circulating fixed bed reactor. The microporous aeration head 7 is connected to the ends of the two gas delivery branches 6 to provide microporous bubbles. The manual air pipe switch valve 3 is arranged on the gas delivery main pipe 2 to control the delivery of the air mixture. Two gas flowmeters 5 are respectively arranged on the gas delivery branch pipes 6 to control the flow rate of the delivered air mixture. The aeration flow rate is set to 0.1VVM.

[0076] The liquid drive system is composed of a peristaltic pump 21, an outflow branch pipe 22, an inflow branch pipe 23, a water pipe quick-connect straight-through 24, a water pipe manual switch valve 25, a fixed bed area liquid delivery branch pipe 26, an outflow area liquid delivery branch pipe 27, and an inflow area liquid delivery branch pipe 28. The peristaltic pump 21 is connected to the outflow branch pipe 22 and the inflow branch pipe 23 to provide a power source for the circulation of the reactants; the fixed bed area liquid delivery branch pipe 26 is used to transfer the reactants in the fixed bed area, passes through the reactor top cover 12, and extends to the bottom of the fixed bed area; the outflow area liquid delivery branch pipe 27 is used to transfer the reactants in the outflow area, passes through the reactor top cover 12, and extends to the bottom of the fixed bed area; Through the reactor top cover 12, it extends to the bottom of the outflow area; the inflow area liquid delivery branch 28 is used to transfer the reactants in the inflow area, passes through the reactor top cover 12, and extends to the bottom of the inflow area; the water pipe manual switch valve 25 is set on the fixed bed area liquid delivery branch 26, the outflow area liquid delivery branch 27 and the inflow area liquid delivery branch 28 to control the delivery of the reactants, and the water pipe quick connection 24 is set at the top of the fixed bed area liquid delivery branch 26, the outflow area liquid delivery branch 27 and the inflow area liquid delivery branch 28 to achieve connection with the outflow branch 22 and the inflow branch 23.

[0077] The photobiological cyclic fixed-bed reaction system in Example 1 uses clinoptilolite filler 15 as the filler in the fixed bed area, which can greatly reduce the concentration of ammonia nitrogen in urine during the cyclic adsorption process, thereby providing a favorable environment for the growth of microalgae. In addition, the clinoptilolite filler 15 loaded with ammonia nitrogen can continuously release ammonia nitrogen into urine with low ammonia nitrogen concentration under the action of concentration gradient pressure, providing a nitrogen source for the growth of microalgae. At the same time, this process also realizes the regeneration of the clinoptilolite filler 15.

[0078] The photobiological cycle fixed-bed reaction system in Example 1 sets the fixed bed area that does not require illumination at the center of the reactor, thereby reducing the impact of insufficient internal irradiation. In addition, by independently setting the fixed bed area, it is beneficial to mix and separate the clinoptilolite filler 15 and the reactants. An inflow area, a first aeration area, a second aeration area, and an outflow area are set outside the fixed bed area. Microalgae are cultured in the above four areas, shortening the light path and improving the photosynthetic efficiency. In addition, various functional units are integrated in a reactor body, which reduces the footprint while reducing the difficulty of operation and management. By switching the liquid pipeline, a variety of operation modes can be changed, which has great flexibility.

[0079] The photobiological cycle fixed bed reaction system in Example 1 uses the arc-shaped light guide plate 29 emitting blue light as a light source, thereby improving the photosynthesis efficiency of microalgae, while facilitating the production of microalgae biomass and the accumulation of intracellular components, which is beneficial to the subsequent development of microalgae resources.

[0080] Embodiment 2: Figures 9 to 12 As shown, in contrast to Example 1, another embodiment of the present invention is as follows: an annular groove is provided on the side wall of the microporous aeration head 7, a slider 43 is slidably connected to the inner wall of the annular groove, a connecting plate 35 is fixedly connected to the side of the slider 43 away from the annular groove, a brush for cleaning the micropores is fixedly connected to the side of the connecting plate 35 close to the microporous aeration head 7, a rotatable connecting shaft 31 is vertically arranged in the microporous aeration head 7, a group of driving blades 32 are fixedly connected to the side wall of the connecting shaft 31, a fixing rod 33 is fixedly connected to the side wall of the micropore of the connecting shaft 31, and the fixing rod 33 is away from the connecting shaft 31. One side is fixedly connected with a first magnetic block 34 which is magnetically attracted to the connecting plate 35. In view of the fact that the micropores of the microporous aeration head 7 may be clogged due to impurities in the gas during long-term use, the above-mentioned mechanism can be used in the present application to allow the gas flow to drive the driving blade 32 to rotate when the gas delivery branch pipe 6 injects gas into the microporous aeration head 7. At this time, the driving blade 32 will drive the connecting shaft 31 to rotate, thereby driving the first magnetic block 34 to rotate. At this time, the connecting plate 35 which is magnetically attracted to the first magnetic block 34 will also rotate. At this time, the bristles will clear and clean the micropores on the microporous aeration head 7 to solve the problem of clogging of the micropores after long-term use.

[0081] The microporous aeration head 7 is sealingly and slidably connected to the side wall of the gas delivery branch pipe 6, a pair of connecting rods 36 are fixedly connected to the bottom surface of the gas delivery branch pipe 6, a disc 37 is fixedly connected to the bottom surface of the connecting rod 36, the top surface of the connecting shaft 31 is rotatably connected to the disc 37, a ring 38 is slidably connected to the side wall of the disc 37, a group of first springs are fixedly connected between the top surface of the ring 38 and the inner wall of the top surface of the microporous aeration head 7, the top surface of the driving blade 32 is fixedly connected to the second magnetic block 40, the bottom surface of the disc 37 is fixedly connected to a group of magnetic sheets 39 corresponding to the second magnetic block 40, and the second magnetic block 40 and the magnetic sheet 39 are arranged to repel each other; in the present application, when the driving blade 32 rotates, the second magnetic block 40 will intermittently pass through the magnetic sheet 39, so that the second magnetic block 40 can intermittently push Magnetic sheet 39, at this time, the ring 38 will push the first spring under the push of the magnetic sheet 39, so that the first spring provides thrust to the microporous aeration head 7, thereby moving the microporous aeration head 7 upward, and when the second magnetic block 40 is away from the magnetic sheet 39, the microporous aeration head 7 will move downward due to weight, so that the microporous aeration head 7 will produce a shaking process, and when the microporous aeration head 7 shakes, the distribution position of the bubbles generated at the micropores will change, and the size and number of the bubbles will change. Smaller bubbles can provide a larger specific surface area, thereby improving the oxygen transfer efficiency, making the distribution of bubbles in the liquid more uniform, and oxygen can be more fully dissolved in the liquid, improving the aeration effect of the liquid, and at the same time, the shaking of the microporous aeration head 7 will disturb the flow of the liquid, increase the miscibility of the liquid, and improve the efficiency of liquid treatment.

[0082] The microporous aeration head 7 is provided with a hollow groove 41, and a sealing plate 42 for sealing the micropores is sealed and slidably connected in the hollow groove 41, and the sealing plate 42 is provided with through holes corresponding to the micropores, and the inner wall of the microporous aeration head 7 is provided with an air inlet connected to the hollow groove 41, and the air inlet is located on the bottom surface of the sealing plate 42, and the outer wall of the microporous aeration head 7 is provided with an air outlet connected to the hollow groove 41, and the air outlet is located on the top surface of the sealing plate 42, and a second spring is fixedly connected between the top surface of the sealing plate 42 and the inner wall of the hollow groove 41; the gas in the present application When injected into the microporous aeration head 7, the gas will first enter the hollow groove 41 from the air inlet to push the sealing plate 42. At this time, the sealing plate 42 will move upward to align the through hole with the micropore. At this time, the gas continuously injected into the microporous aeration head 7 can be evenly discharged from the micropores, so that bubbles can be evenly generated to improve the uniformity of the bubbles. At the same time, when the microporous aeration head 7 shakes, the sealing plate 42 will also shake slightly. At this time, there will be a misalignment between the through hole and the micropore, reducing the aperture of the micropore, so that the gas discharged from the micropore can generate more and smaller bubbles.

[0083] like Fig.13As shown, a photobiological cycle fixed bed reaction method for purifying urine based on microalgae is used. The method adopts the above-mentioned photobiological cycle fixed bed reaction system for purifying urine based on microalgae. The method comprises the following steps:

[0084] S1: Introduce urine into the circulating fixed bed reactor through the water inlet, connect the outflow branch pipe with the fixed bed liquid delivery branch pipe, connect the inflow branch pipe with the outflow zone liquid delivery branch pipe, start the peristaltic pump, and circulate the urine in the circulating fixed bed reactor until saturation, and then turn off the peristaltic pump;

[0085] S2: Connect the outflow branch pipe to the liquid delivery branch pipe in the inflow area, connect the inflow branch pipe to the liquid delivery branch pipe in the fixed bed area, start the peristaltic pump, discharge the residual urine in the fixed bed area into the inflow area, and then turn off the peristaltic pump;

[0086] S3: inoculating microalgae into the circulating fixed bed reactor through the water inlet, connecting the outflow branch pipe with the inflow area liquid delivery branch pipe, connecting the inflow branch pipe with the outflow area liquid delivery branch pipe, and starting the aerator and the peristaltic pump for circulating cultivation of microalgae;

[0087] S4: The lighting effects of day and night are differentiated by turning on and off the LED light strips. The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches stability, the aerator and peristaltic pump are turned off.

[0088] S5: The urine and microalgae mixture is discharged through the drain port, and after the algae-water separation, the separated urine is collected and introduced into the circulating fixed bed reactor through the water inlet, and the microalgae are inoculated through the water inlet;

[0089] S6: During the day, the outflow branch pipe is connected to the liquid delivery branch pipe of the inflow area, the inflow branch pipe is connected to the liquid delivery branch pipe of the outflow area, and the aerator and the peristaltic pump are turned on to perform suspension culture of microalgae;

[0090] S7: At night, turn off the aerator and the peristaltic pump, connect the outflow branch pipe to the fixed bed liquid delivery branch pipe, connect the inflow branch pipe to the outflow zone liquid delivery branch pipe, and then turn on the peristaltic pump to regenerate the clinoptilolite filler with the urine and microalgae mixture, and realize the zeolite-based microalgae circulation culture;

[0091] S8: The lighting effects of day and night are differentiated by turning on and off the LED light strips. The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches stability, the process ends, the aerator and peristaltic pump are turned off, and the urine and microalgae mixture is discharged from the drain port for algae-water separation.

[0092] Working principle: 1L urine is introduced into the circulating fixed bed reactor through the water inlet 16, the outflow branch 22 is connected to the fixed bed liquid delivery branch 26, the inflow branch 23 is connected to the outflow zone liquid delivery branch 27, the peristaltic pump 21 is started, the flow rate of the peristaltic pump 21 is 60ml / min, the urine is introduced into the bottom of the fixed bed zone, and flows from the bottom to the top, forming an effluent overflow, and enters the inflow zone, the first aeration zone, the second aeration zone and the outflow zone in turn, and finally introduced from the outflow zone to the fixed bed zone through the peristaltic pump 21. This process is continuously cycled until adsorption is saturated. This step is run for 2 days, and then the peristaltic pump 21 is turned off;

[0093] The outflow branch pipe 22 is connected to the inflow area liquid delivery branch pipe 28, the inflow branch pipe 23 is connected to the fixed bed area liquid delivery branch pipe 26, the peristaltic pump 21 is turned on, the flow rate of the peristaltic pump 21 is 100ml / min, the residual urine in the fixed bed area is discharged into the inflow area, and then the peristaltic pump 21 is turned off, and the protein nucleus Chlorella is inoculated into the circulating fixed bed reactor through the water inlet 16, the outflow branch pipe 22 is connected to the inflow area liquid delivery branch pipe 28, the inflow branch pipe 23 is connected to the outflow area liquid delivery branch pipe 27, and the aerator 1 and the peristaltic pump 21 are turned on, and the aeration gas source is air Mixed gas (CO2 volume fraction is 5%), aeration flow rate is 0.1VVM, and the flow rate of the peristaltic pump 21 is 60ml / min. At this time, the circulation order of the urine and protein nucleus Chlorella mixed liquid is the inflow area, the first aeration area, the second aeration area and the outflow area. The lighting effect of day and night is distinguished by turning on and off the LED light strip 30. The time of day and night is 14 hours and 10 hours respectively. This cycle is continuously circulated. This step runs for 15 days, and then the growth of protein nucleus Chlorella reaches stability. Finally, the aerator 1 and the peristaltic pump 21 are turned off;

[0094] The urine and protein-core Chlorella mixed liquid is discharged through the drain port 18, and after the algae-water separation, the separated urine is collected and introduced into the circulating fixed bed reactor through the water inlet 16, and the protein-core Chlorella is inoculated through the water inlet 16; during the day, the outflow branch pipe 22 is connected to the inflow area liquid delivery branch pipe 28, the inflow branch pipe 23 is connected to the outflow area liquid delivery branch pipe 27, the aerator 1 and the peristaltic pump 21 are turned on, the aeration gas source is an air mixture (CO2 volume fraction is 5%), the aeration flow rate is 0.1VVM, the peristaltic pump 21 flow rate is 60ml / min, and the units involved in the circulation are the inflow area, the first aeration area, the second aeration area and the outflow area. At night, turn off the aerator 1 and the peristaltic pump 21, connect the outflow branch 22 to the fixed bed liquid delivery branch 26, connect the inflow branch 23 to the outflow area liquid delivery branch 27, and then turn on the peristaltic pump 21. The flow rate of the peristaltic pump 21 is 60 ml / min. At this time, the units involved in the circulation are the inflow area, the first aeration area, the second aeration area, the outflow area, and the fixed bed area. The lighting effects of day and night are distinguished by turning on and off the LED light strip 30. The time of day and night is 14 hours and 10 hours respectively. This cycle is continuously cycled. The operation period of this step is 13 days. At this time, the growth of protein nucleus Chlorella reaches stability, turn off the aerator 1 and the peristaltic pump 21, and discharge the urine and protein nucleus Chlorella mixed liquid from the drain port 18 for algae-water separation.

[0095] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0096] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0097] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A photobiological cycle fixed bed reaction system for purifying urine based on microalgae, comprising a cycle fixed bed reactor, a lighting system, an aeration system and a liquid drive system; Features: The circulating fixed bed reactor comprises a reactor outer cylinder (13) and a reactor inner cylinder (14), both of which are transparent hollow structures and have the same height, and the reactor inner cylinder (14) is coaxially fixed inside the reactor outer cylinder (13); A reactor bottom plate (20) is arranged at the bottom of the reactor outer cylinder (13) and the reactor inner cylinder (14); A reactor top cover (12) is arranged on the top of the reactor outer cylinder (13) and the reactor inner cylinder (14); The first baffle (8), the second baffle (9), the third baffle (10), and the fourth baffle (11) are all made of transparent materials, have the same height as the reactor outer cylinder (13) and the reactor inner cylinder (14), and are vertically arranged in the space between the reactor outer cylinder (13) and the reactor inner cylinder (14), dividing the space into four chambers of equal volume, namely, an inflow zone, a first aeration zone, a second aeration zone, and an outflow zone. The first baffle (8), the second baffle (9), and the third baffle (10) are provided with circular holes to ensure the flow of reactants between the chambers; The clinoptilolite filler (15) is filled in the inner cylinder (14) of the reactor, which is called the fixed bed zone. The particle size of the clinoptilolite filler (15) is 1-3 mm, and the filling volume accounts for 80-90% of the volume of the fixed bed zone. The reactor inner cylinder (14) is cut off at the upper part of the inflow zone to ensure the overflow of effluent, the upper interface of the cutoff is flush with the height of the reactor inner cylinder (14), and the lower interface of the cutoff is higher than the height of the fixed bed zone; The holes of the first baffle (8) are arranged at the bottom, the holes of the second baffle (9) are arranged at the top and the upper limit of the holes is not higher than the lower interface of the cutoff of the inner cylinder (14) of the reactor, and the holes of the third baffle (10) are arranged at the bottom; A water inlet (16), disposed on the reactor top cover (12), for injecting the reactants and inoculating the microalgae; An exhaust valve (17), arranged on the reactor top cover (12), for exhausting excess gas in the circulating fixed bed reactor; A drain port (18) is provided at the bottom of the outer cylinder (13) of the reactor and is used to drain the reactants in the circulating fixed bed reactor; The reactor base (19) is arranged below the reactor bottom plate (20) and is used to support the circulating fixed bed reactor body.

2. The photobiological cycle fixed bed reaction system for purifying urine based on microalgae according to claim 1 is characterized by: The lighting system comprises an arc-shaped light guide plate (29), which is arranged outside the circulating fixed bed reactor and is used to provide light for the cultured microalgae; The LED light strip (30) is attached to the upper thickness surface of the arc-shaped light guide plate (29), and provides a blue light spectrum; The arc surface of the arc-shaped light guide plate (29) closer to the circulating fixed bed reactor serves as a light emitting surface, and the arc surface farther from the circulating fixed bed reactor and other thickness surfaces are attached with reflective films as reflective surfaces.

3. The photobiological cycle fixed bed reaction system for purifying urine based on microalgae according to claim 2 is characterized by: The aeration system comprises an aerator (1), and the aerator (1) provides air mixed gas for the circulating fixed bed reactor; A gas delivery main pipe (2), connected to the aerator (1), for delivering the air mixture; A manual air pipe switch valve (3) is arranged on the gas delivery main pipe (2) to control the delivery of the air mixture; A gas delivery branch pipe (6) passes through the reactor top cover (12) and extends into the first aeration zone and the second aeration zone of the circulating fixed bed reactor; A gas three-way joint (4) connected to the gas delivery main pipe (2) and the gas delivery branch pipe (6); A gas flow meter (5), arranged on the gas delivery branch pipe (6), for controlling the aeration flow rate; A microporous aeration head (7) is arranged at the end of the gas delivery branch pipe (6) and is used to generate microporous bubbles.

4. The photobiological cycle fixed bed reaction system for purifying urine based on microalgae according to claim 3 is characterized by: The liquid drive system comprises a peristaltic pump (21), and the peristaltic pump (21) provides a power source for the circulation of the reactants; The outflow branch pipe (22) and the inflow branch pipe (23) are connected to the peristaltic pump (21); A fixed bed zone liquid delivery branch pipe (26), used for transferring the reactants in the fixed bed zone, passes through the reactor top cover (12), and extends to the bottom of the fixed bed zone; An outflow zone liquid delivery branch pipe (27), used for transferring the reactants in the outflow zone, passes through the reactor top cover (12), and extends to the bottom of the outflow zone; An inflow zone liquid delivery branch pipe (28), used for transferring the reactants in the inflow zone, passes through the reactor top cover (12), and extends to the bottom of the inflow zone; A water pipe quick-connect straight-through (24) is arranged at the top of the fixed bed area liquid delivery branch pipe (26), the outflow area liquid delivery branch pipe (27), and the inflow area liquid delivery branch pipe (28) to achieve connection with the outflow branch pipe (22) and the inflow branch pipe (23); A manual water pipe switch valve (25) is arranged on the fixed bed area liquid delivery branch pipe (26), the outflow area liquid delivery branch pipe (27), and the inflow area liquid delivery branch pipe (28) to control the delivery of the reactants.

5. The photobiological cycle fixed bed reaction system based on microalgae for purifying urine according to claim 4, characterized in that: The side wall of the microporous aeration head (7) is provided with an annular groove, the inner wall of the annular groove is slidably connected to a slider (43), the side of the slider (43) away from the annular groove is fixedly connected to a connecting plate (35), the side of the connecting plate (35) close to the microporous aeration head (7) is fixedly connected to bristles for cleaning the micropores, a rotatable connecting shaft (31) is vertically arranged in the microporous aeration head (7), the side wall of the connecting shaft (31) is fixedly connected to a group of driving blades (32), the side wall of the micropore corresponding to the driving blade (32) of the connecting shaft (31) is fixedly connected to a fixing rod (33), and the side of the fixing rod (33) away from the connecting shaft (31) is fixedly connected to a first magnetic block (34) magnetically attracted to the connecting plate (35).

6. The photobiological cycle fixed bed reaction system for purifying urine based on microalgae according to claim 5, characterized in that: The microporous aeration head (7) is sealingly and slidably connected to the side wall of the gas delivery branch pipe (6); a pair of connecting rods (36) are fixedly connected to the bottom surface of the gas delivery branch pipe (6); a disk (37) is fixedly connected to the bottom surface of the connecting rod (36); the top surface of the connecting shaft (31) is rotatably connected to the disk (37); a ring (38) is slidably connected to the side wall of the disk (37); a group of first springs are fixedly connected between the top surface of the ring (38) and the inner wall of the top surface of the microporous aeration head (7); a second magnetic block (40) is fixedly connected to the top surface of the driving blade (32); a group of magnetic sheets (39) corresponding to the second magnetic block (40) are fixedly connected to the bottom surface of the disk (37); the second magnetic block (40) and the magnetic sheets (39) are arranged to repel each other.

7. The photobiological cycle fixed bed reaction system for purifying urine based on microalgae according to claim 6, characterized in that: The microporous aeration head (7) is provided with a hollow groove (41), a sealing plate (42) for sealing the micropores is sealingly and slidably connected inside the hollow groove (41), the sealing plate (42) is provided with through holes corresponding to the micropores, the inner wall of the microporous aeration head (7) is provided with an air inlet hole connected to the hollow groove (41), the air inlet hole is located on the bottom surface of the sealing plate (42), the outer wall of the microporous aeration head (7) is provided with an air outlet hole connected to the hollow groove (41), the air outlet hole is located on the top surface of the sealing plate (42), and a second spring is fixedly connected between the top surface of the sealing plate (42) and the inner wall of the hollow groove (41).

8. A photobiological cycle fixed bed reaction method for purifying urine based on microalgae, the method adopts the photobiological cycle fixed bed reaction system for purifying urine based on microalgae as claimed in claim 7, characterized in that: The method comprises the following steps: S1: urine is introduced into the circulating fixed bed reactor through the water inlet (16), the outflow branch pipe (22) is connected to the fixed bed liquid delivery branch pipe (26), the inflow branch pipe (23) is connected to the outflow zone liquid delivery branch pipe (27), the peristaltic pump (21) is started, and the urine is circulated and adsorbed in the circulating fixed bed reactor until saturation, and then the peristaltic pump (21) is turned off; S2: connecting the outflow branch pipe (22) to the inflow area liquid delivery branch pipe (28), connecting the inflow branch pipe (23) to the fixed bed area liquid delivery branch pipe (26), starting the peristaltic pump (21), draining the residual urine in the fixed bed area into the inflow area, and then closing the peristaltic pump (21); S3: inoculating microalgae into the circulating fixed bed reactor through the water inlet (16), connecting the outflow branch pipe (22) with the inflow zone liquid delivery branch pipe (28), connecting the inflow branch pipe (23) with the outflow zone liquid delivery branch pipe (27), and starting the aerator (1) and the peristaltic pump (21) to carry out circulating cultivation of the microalgae; S4: The lighting effects of day and night are differentiated by turning on and off the LED light strip (30). The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches stability, the aerator (1) and the peristaltic pump (21) are turned off.

9. The photobiological cycle fixed bed reaction method for purifying urine based on microalgae according to claim 8, characterized in that: The method further comprises the steps of: S5: The urine and microalgae mixture is discharged through the drain port (18), and after the algae-water separation, the separated urine is collected and introduced into the circulating fixed bed reactor through the water inlet (16), and the microalgae are inoculated through the water inlet (16); S6: During the day, the outflow branch pipe (22) is connected to the inflow area liquid delivery branch pipe (28), the inflow branch pipe (23) is connected to the outflow area liquid delivery branch pipe (27), and the aerator (1) and the peristaltic pump (21) are turned on to perform suspension culture of microalgae; S7: At night, turn off the aerator (1) and the peristaltic pump (21), connect the outflow branch pipe (22) to the fixed bed liquid delivery branch pipe, connect the inflow branch pipe (23) to the outflow zone liquid delivery branch pipe (27), then turn on the peristaltic pump (21), and use the urine and microalgae mixture to regenerate the clinoptilolite filler (15), while realizing the zeolite-based microalgae circulation culture; S8: The lighting effects of day and night are differentiated by turning the LED light strip (30) on and off. The time of day and night is 14 hours and 10 hours respectively. This cycle is repeated continuously. When the growth of microalgae reaches a stable state, the process ends. The aerator (1) and the peristaltic pump (21) are turned off, and the urine and microalgae mixture is discharged from the drain port (18) to separate the algae from water.

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