A device and method for carbon capture and phosphorus removal by efficient low-consumption high-load contact stabilization

Abstract

The application discloses a device and method for carbon capture and phosphorus removal by high-efficiency low-consumption high-load contact stabilization, the device comprising a sewage pool, an SBR reactor communicated with the sewage pool, a denitrification reaction tank communicated with a water outlet pipe in the middle of the SBR reactor, an anaerobic digestion tank communicated with a sludge discharge pipe at the bottom of the SBR reactor, and a biological carbon sludge removal device arranged on one side of the anaerobic digestion tank. The method comprises the following steps: S1, water feeding and stirring; S2, SBR treatment; S3, sludge fermentation; and S4, magnetic biological carbon recovery. The magnetic biological carbon is added into the SBR reactor with high-load contact stabilization, so that the adsorption of organic carbon and phosphorus in the sewage is simultaneously promoted, the collection effect of the dissolved organic matter is further improved, the adsorption of the organic carbon and the phosphorus in the sewage is promoted, and the stable and efficient carbon capture and phosphorus removal effect is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, in particular to a device and method for carbon capture and phosphorus removal by high-efficiency low-consumption high-load contact stabilization. BACKGROUND

[0002] Currently, activated sludge method is mainly used for sewage treatment, but the traditional activated sludge method has problems such as high energy consumption and high carbon emission. Under the premise of realizing the standard discharge of municipal sewage treatment, promoting the low-carbon operation of sewage plants through sewage energy recovery has become the focus of attention. The organic carbon in municipal sewage contains rich chemical energy, and efficient capture of organic carbon in the influent is one of the key measures to realize the low-carbon operation of sewage plants. Researchers at home and abroad have studied sewage organic carbon capture technology, mainly including chemical enhanced primary treatment, high-load membrane separation technology and high-load activated sludge method. Chemical enhanced primary treatment and high-load membrane separation technology can achieve high organic carbon capture efficiency, but they respectively rely on large amounts of coagulant addition and extremely high investment cost, and have high operating cost and difficulties in large-scale popularization and application.

[0003] High-load activated sludge method (HRAS) has very short sludge retention time and hydraulic retention time, and can effectively capture organic carbon through biological flocculation while maintaining a low organic carbon mineralization rate. HRAS mainly relies on biological flocculation, has low operating cost and good economic benefit, and can realize effective removal of nitrogen by being combined with low-carbon denitrification process. For example, the coupling process of HRAS and anaerobic ammonia oxidation was used in Strass sewage plant in Austria, which realized 160% of energy self-sufficiency rate in 2013. However, the characteristics of very short sludge retention time (SRT) and hydraulic retention time (HRT) limit the capture ability of soluble organic matter and the removal ability of phosphorus of the process, which restricts the popularization and application of the process.

[0004] Biochar is an ideal adsorbent for soluble organic matter due to its economic efficiency, high adsorption efficiency and production from biomass waste. However, powder biochar is difficult to separate from water, often requiring centrifugation or filtration. Introducing Fe3O4 with magnetism into the biochar matrix to prepare magnetic biochar is an effective solution to this problem, and Fe3O4 can also form complexes with phosphates, thereby improving phosphorus removal efficiency. Biochar with magnetism can be quickly recovered by magnetic separation, thereby realizing simultaneous enhancement of organic carbon capture, phosphorus adsorption and removal, and solid-liquid separation. In addition, the magnetic material in the magnetic biochar also has a magnetic effect on microorganisms, further improving the process performance and subsequent sludge anaerobic digestion energy resource recovery efficiency. Therefore, exploring the carbon capture enhancement technology of high-load activated sludge process based on magnetic biochar can provide support for the optimization control and popularization and application of the process, and has important significance for the low-carbon operation of wastewater treatment plants. At present, the magnetic biochar combined with high-load activated sludge for treating wastewater still needs further research. SUMMARY

[0005] In view of the above problems, the present application provides a device and method for carbon capture and phosphorus removal by high-efficiency low-consumption high-load contact stabilization process.

[0006] The technical scheme of the present application is:

[0007] A device for carbon capture and phosphorus removal by high-efficiency low-consumption high-load contact stabilization process, comprising a sewage pool, an SBR reactor communicating with the sewage pool, a denitrification reaction tank communicating with the SBR reactor middle water outlet pipe, and an anaerobic digestion tank communicating with the SBR reactor bottom sludge discharge pipe.

[0008] The sewage pool is provided with a water inlet stirrer, the SBR reactor bottom is provided with an aeration pipe on one side, the SBR reactor top is provided with a reaction stirrer, and the SBR reactor top is provided with a biochar feeder on one side.

[0009] The anaerobic digestion tank is provided with a biochar sludge removal device on one side, and the biochar sludge removal device is provided with a biochar backflow tank connected with the biochar feeder through a backflow pipe.

[0010] Further, the sewage pool and the SBR reactor are connected by a sewage pipe, and the sewage pipe is provided with a sewage pump in the middle.

[0011] Note: The continuous stirring of the sewage pool enables the particulate matter in the sewage to uniformly enter the SBR reactor.

[0012] Further, the aeration pipe is provided with an air pump at the end, the water outlet pipe is provided with a water outlet pump in the middle, and the sludge discharge pipe is provided with a sludge discharge pump in the middle.

[0013] Further, the upper surface of the electromagnet is concentric with the bottom of the SBR reactor, and the coverage area of the electromagnet is greater than 75% of the area of the bottom of the SBR reactor.

[0014] Description: The sedimentation time of sludge and magnetic biochar can be easily controlled by the electromagnet, and the sedimentation efficiency of sludge and magnetic biochar can be ensured by adjusting the coverage area of the electromagnet.

[0015] Further, the top of the anaerobic digester is provided with a biogas discharge pipe.

[0016] Description: The sludge containing magnetic biochar is treated by anaerobic digestion, which can greatly improve the biogas production, shorten the start-up time of the anaerobic digester, and increase the methane content in the biogas, thereby improving the energy utilization efficiency and resource utilization efficiency of wastewater.

[0017] Further, the biochar sludge removal device comprises an ultrasonic sludge removal bin, a main motor is arranged at the top of the ultrasonic sludge removal bin, a rotating shaft is arranged at the output end below the main motor, a plurality of auxiliary motors are arranged on the upper part of the rotating shaft at equal intervals in the circumferential direction, a telescopic rod is arranged at the output end below each auxiliary motor, a magnetic plate is fixedly connected to the end of each telescopic rod, each magnetic plate is arranged at equal intervals in the vertical direction, a plurality of grooves are arranged on the side wall of the rotating shaft, each telescopic rod corresponds to one groove, and the groove extends to the position of the corresponding magnetic plate, the bottom of the telescopic rod and the inner end of the magnetic plate are fixedly connected to a fixed block, the fixed block slides up and down in the groove, an auxiliary stirring rod is arranged on the outer wall of the rotating shaft on both sides of the magnetic plate or between adjacent grooves, a slot is arranged on the upper part of one side wall of the ultrasonic sludge removal bin, a biochar return tank slides in the slot, a sliding block is arranged at the bottom of the biochar return tank, the sliding block slides and is limitingly connected to a sliding groove arranged at the bottom of the slot, a scraper is arranged on one side of the biochar return tank for abutting and connecting with the bottom of the magnetic plate and scraping off the magnetic biochar, a hydraulic push rod is arranged on the side wall of the ultrasonic sludge removal bin below the slot, the output end of the hydraulic push rod is fixedly connected to the front end of the bottom of the biochar return tank, and when the biochar return tank slides out of the slot to the maximum position, a return pipe is arranged above the biochar return tank.

[0018] Description: The biochar sludge removal device can quickly clean and remove the magnetic biochar after anaerobic digestion, and is timely reused.

[0019] Further, the main motor is fixedly connected to the ultrasonic sludge removal bin through fixed rods on both sides, the auxiliary motors are three, the corresponding telescopic rods and magnetic plates are three, one auxiliary stirring rod is arranged on each side of the lowermost magnetic plate, one auxiliary stirring rod is arranged on one side of the middle magnetic plate, and three auxiliary stirring rods are arranged on the outer wall of the rotating shaft between the two adjacent grooves above the uppermost magnetic plate.

[0020] Description: By optimizing the number of magnetic adsorption plates to ensure the cleaning efficiency of magnetic biochar while improving the recovery speed.

[0021] A method for carbon capture and phosphorus removal with high efficiency, low consumption and high load contact stabilization, based on the device for carbon capture and phosphorus removal with high efficiency, low consumption and high load contact stabilization described in any of the above, comprising the following steps:

[0022] S1, water stirring: the sewage is injected into the sewage pool and stirred uniformly by the water stirring device, and then injected into the SBR reactor;

[0023] S2, SBR treatment: the operation mode of the SBR reactor includes a single operation cycle, which includes a contact section, a sedimentation section, a drainage section and a stabilization section;

[0024] S2-1, contact section: first, water is fed while magnetic biochar is added through a biochar feeder within 5-10 minutes, and the sewage is contacted with the magnetic biochar for 10-15 minutes without aeration, and the magnetic biochar dosage is 100-500 mg / L;

[0025] S2-2, sedimentation section: the electromagnet is turned on to use the magnetic field to promote the sedimentation of magnetic biochar and sludge, and the sedimentation time is 10-30 minutes to ensure efficient separation of sludge and water in the SBR reactor;

[0026] S2-3, drainage section: open the water outlet to drain water within 5-10 minutes, and drain the sewage in the SBR reactor to half the water level, and then drain the treated sewage into a denitrification reaction tank for denitrification treatment;

[0027] S2-4, stabilization section: open the aeration pipe to aerate the remaining sewage and sludge in the SBR reactor for 40-50 minutes, with dissolved oxygen concentration controlled at 1.5-2 mg / L, and reaction agitator speed at 60-150 rpm, then a portion of the sludge is discharged to an anaerobic digestion tank through a sludge discharge pipe, and the sludge retention time in the SBR reactor is controlled at 0.5-1 day, then S1 and S2 are repeated to treat the next batch of sewage;

[0028] S3, sludge fermentation: control the temperature in the anaerobic digestion tank at 37±0.2℃, and set the stirring speed at 100-120 rpm, ferment for 20-25 days, collect the biogas at the top of the anaerobic digestion tank, and then discharge the remaining sludge to the biochar sludge removal device;

[0029] S4, magnetic biochar recovery: the remaining sludge is washed and sludge is removed by the biochar sludge removal device to obtain reused magnetic biochar, and the reused magnetic biochar is added to the biochar feeder through the reflux pipe for reuse.

[0030] Further, the preparation method of the magnetic biochar is as follows: one or more of coconut shell, wood chips or rice husk biochar is mixed, then mixed with stainless steel balls in a mass ratio of 1:100, loaded into a stainless steel grinding jar for grinding, sieved through a 200 mesh sieve to obtain biomass powder, the diameter of the stainless steel balls is less than 3 mm, the biomass powder is mixed with magnetic powder in a mass ratio of 1:2-4, loaded into a planetary ball mill, the planetary ball mill is operated at a speed of 300-400 rpm for 10-12 hours, then washed with Milli-Q water and ethanol alternately for 3 times, then the supernatant is removed by magnetic separation, and the magnetic biochar is dried at 60-70 DEG C to obtain the magnetic biochar.

[0031] Description: By adding the magnetic biochar into the high-load contact stable SBR reactor, the magnetic biochar can not only be used as an attachment place for microorganisms, but also can directly form a complex with phosphorus, and simultaneously promote the adsorption of organic carbon and phosphorus in wastewater.

[0032] The beneficial effects of the present application are:

[0033] (1) The device and method for carbon capture and phosphorus removal of the present application can promote the adsorption of organic carbon and phosphorus in wastewater by adding the magnetic biochar into the high-load contact stable SBR reactor, and the magnetic biochar can not only be used as an attachment place for microorganisms, but also can directly form a complex with phosphorus, and simultaneously promote the adsorption of organic carbon and phosphorus in wastewater, and under the action of stirring, the reaction flow field can be uniformly distributed, the contact efficiency of wastewater, sludge and magnetic biochar can be improved, the capture effect of dissolved organic matter can be further improved, the adsorption of organic carbon and phosphorus in wastewater can be promoted, and the stable and efficient carbon capture and phosphorus removal effect can be ensured.

[0034] (2) The device and method for carbon capture and phosphorus removal of the present application can promote the adsorption of organic carbon and phosphorus in wastewater by adding the magnetic biochar into the high-load contact stable SBR reactor, and the magnetic biochar can not only be used as an attachment place for microorganisms, but also can directly form a complex with phosphorus, and simultaneously promote the adsorption of organic carbon and phosphorus in wastewater, and under the action of stirring, the reaction flow field can be uniformly distributed, the contact efficiency of wastewater, sludge and magnetic biochar can be improved, the capture effect of dissolved organic matter can be further improved, the adsorption of organic carbon and phosphorus in wastewater can be promoted, and the stable and efficient carbon capture and phosphorus removal effect can be ensured.

[0035] (3) The device and method for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method can perform anaerobic digestion treatment on the mixture of discharged magnetic biochar and sludge, greatly improve the biogas production, shorten the start-up time of the anaerobic digester, and the methane content in the biogas is higher, thereby improving the energy utilization and resource utilization efficiency of the sewage, and the magnetic biochar after anaerobic digestion can be reused after simple cleaning, the biochar sludge removal device is simple in structure, convenient to operate and stable in operation, and finally the capture efficiency of organic carbon in the sewage is effectively improved, the phosphorus removal effect is good, the sludge settling rate is fast, the energy and material consumption is low, and the stable, efficient and low-consumption sewage carbon capture and phosphorus removal effect is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a whole structure schematic diagram of the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method;

[0037] Figure 2 is a front view of the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method;

[0038] Figure 3 is a structure schematic diagram of a biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method;

[0039] Figure 4 is a structure schematic diagram of a biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method;

[0040] Figure 5 is a side view of the biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method;

[0041] Figure 6 is a front view of the biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method, wherein an ultrasonic sludge removal bin is omitted;

[0042] Figure 7 is a front view of the biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method, wherein the ultrasonic sludge removal bin is omitted and a biochar reflux tank is moved;

[0043] Figure 8 is a structure schematic diagram of a rotating shaft and a magnetic attraction plate connection of the biochar sludge removal device in the device for capturing carbon and removing phosphorus with high efficiency, low consumption and high load contact stabilization method.

[0044] Wherein, 1 - sewage pool, 11 - water inlet stirrer, 12 - sewage pipe, 13 - sewage pump, 2 - SBR reactor, 21 - water outlet pipe, 22 - sludge discharge pipe, 23 - aeration pipe, 24 - reaction stirrer, 25 - electromagnet, 26 - air pump, 27 - water pump, 28 - sludge pump, 3 - denitrification reaction tank, 4 - anaerobic digester, 41 - biogas discharge pipe, 5 - biochar dosing device, 51 - reflux pipe, 6 - biochar sludge removal device, 61 - biochar reflux tank, 611 - sliding block, 612 - scraper, 62 - ultrasonic sludge removal bin, 621 - slot, 622 - chute, 63 - main motor, 631 - fixed rod, 64 - rotating shaft, 641 - groove, 642 - auxiliary stirring rod, 65 - auxiliary motor, 66 - telescopic rod, 67 - magnetic plate, 671 - fixed block, 68 - hydraulic push rod. DETAILED DESCRIPTION

[0045] Example 1

[0046] As shown in Figure 1 , a high-efficiency low-consumption high-load contact stabilization method for carbon capture and phosphorus removal device, including sewage pool 1, SBR reactor 2 in communication with sewage pool 1, denitrification reaction tank 3 in communication with SBR reactor 2 middle water outlet pipe 21, anaerobic digester 4 in communication with SBR reactor 2 bottom sludge discharge pipe 22;

[0047] As shown in Figure 2 , the sewage pool 1 is provided with water inlet stirrer 11, the sewage pool 1 and SBR reactor 2 are communicated by sewage pipe 12, the sewage pipe 12 is provided with sewage pump 13 in the middle;

[0048] As shown in Figure 1 and 2 , the SBR reactor 2 bottom side is provided with aeration pipe 23, the SBR reactor 2 top is provided with reaction stirrer 24, the SBR reactor 2 top side is provided with biochar dosing device 5, the biochar dosing device 5 is a small fish feed automatic dosing device on the market, the SBR reactor 2 bottom is provided with electromagnet 25, the upper surface of electromagnet 25 and the bottom of SBR reactor 2 are concentric circles, and the coverage area of electromagnet 25 is 80% of the area of SBR reactor 2 bottom, the aeration pipe 23 end is provided with air pump 26, the water outlet pipe 21 middle is provided with water pump 27, the sludge discharge pipe 22 middle is provided with sludge pump 28;

[0049] As shown in Figure 2 and 3 , the anaerobic digester 4 top is provided with biogas discharge pipe 41, the anaerobic digester 4 side is provided with biochar sludge removal device 6, the biochar sludge removal device 6 is provided with biochar reflux tank 61, which is connected with biochar dosing device 5 through reflux pipe 51;

[0050] As shown in Figures 3-8As shown, the biochar desludging device 6 includes an ultrasonic desludging bin 62, a main motor 63 is provided on the top of the ultrasonic desludging bin 62, and both sides of the main motor 63 are fixedly connected to the ultrasonic desludging bin 62 through fixed rods 631. A rotating shaft 64 is provided at the output end below the main motor 63, and three auxiliary motors 65 are provided at equal intervals on the upper part of the rotating shaft 64. A telescopic rod 66 is provided at the output end below the auxiliary motor 65, and a magnetic plate 67 is fixedly connected to the end of the telescopic rod 66. Each magnetic plate 67 is arranged at equal intervals in the vertical direction. Three grooves 641 are provided on the side wall of the rotating shaft 64, and each telescopic rod 66 corresponds to each groove 641 one by one, and the groove 641 extends to the corresponding At the position of the magnetic plate 67, the bottom of the telescopic rod 66 is fixedly connected to the fixed block 671 provided at the inner end of the magnetic plate 67, and the fixed block 671 slides up and down in the groove 641. Auxiliary stirring rods 642 are provided on the outer wall of the rotating shaft 64 on both sides of the magnetic plate 67, or on the outer wall of the rotating shaft 64 between two adjacent grooves 641. An auxiliary stirring rod 642 is provided on each side of the lowest magnetic plate 67, an auxiliary stirring rod 642 is provided on one side of a magnetic plate 67 located in the middle, and three auxiliary stirring rods 642 are provided on the outer wall of the rotating shaft 64 between two adjacent grooves 641 above the uppermost magnetic plate 67;

[0051] like Figure 3 、 5 As shown in FIG8 , a slot 621 is provided on the upper part of one side wall of the ultrasonic desludging bin 62, and the biochar reflux trough 61 slides inside the slot 621. A slider 611 is provided at the bottom of the biochar reflux trough 61, and the slider 611 slides and is limitedly connected to the slide groove 622 provided at the bottom of the slot 621. A scraper 612 is provided on one side of the biochar reflux trough 61 for fitting with the bottom of the magnetic plate 67 and scraping off the magnetic biochar. A hydraulic push rod 68 is provided on the side wall of the ultrasonic desludging bin 62 below the slot 621, and the output end of the hydraulic push rod 68 is fixedly connected to the front end of the bottom of the biochar reflux trough 61. When the biochar reflux trough 61 slides out of the slot 621 to the maximum position, the reflux pipe 51 corresponds to the top of the biochar reflux trough 61.

[0052] The main motor 63 and the auxiliary motor 65 are both commercially available gear reduction motors, and the water inlet agitator 11 and the reaction agitator 24 both use commercially available three-blade agitator paddles. The reaction agitator 24 has an inclination angle of 30°, a diameter ratio to the tank diameter of the SBR reactor 2 of 0.3, and a distance from the bottom of the SBR reactor 2 to 15% of the reactor height.

[0053] Working principle:

[0054] Below we briefly describe the specific working principle of the biochar desludging device 6.

[0055] In use, the sludge containing magnetic biochar is injected into the ultrasonic desludging bin 62, clean water is added, the amount of clean water added is 3-4 times the amount of sludge, the ultrasonic controller of the ultrasonic desludging bin 62 is turned on, the ultrasonic power is adjusted to 800-1200W, ultrasonic treatment is carried out, at the same time the main motor 63 is turned on to drive the rotating shaft 64 to rotate, so that the magnetic biochar detached during ultrasonic cleaning is magnetically adsorbed at the bottom of the magnetic adsorption plate 67, and every 5 minutes, one magnetic adsorption plate 67 is scraped off;

[0056] The scraping method is: the corresponding auxiliary motor 65 above the magnetic adsorption plate 67 is turned on, which drives the magnetic adsorption plate 67 to rotate and move upwards at the same time through the telescopic rod 66, until it moves upwards to the horizontal plane where the top of the scraping plate 612 is located, then the hydraulic push rod 68 is turned on to drive the biochar backflow tank 61 to slide into the ultrasonic desludging bin 62, as Figure 6 The state becomes Figure 7 The state becomes, the biochar backflow tank 61 is located at the bottom of the magnetic adsorption plate 67, and the magnetic biochar attached during rotation is scraped off and falls into the biochar backflow tank 61 through the contact with the scraping plate 612, then the biochar backflow tank 61 is reset;

[0057] The magnetic biochar attached to each magnetic adsorption plate 67 is scraped off in turn, and the magnetic biochar is introduced into the biochar feeding device 5 through the backflow pipe 51.

[0058] Example 2

[0059] The difference between this embodiment and example 1 is:

[0060] Two auxiliary motors 65 are arranged on the upper part of the rotating shaft 64 in equal intervals in the circumferential direction, and the number of magnetic adsorption plates 67, sliding blocks 611 and telescopic rods 66 corresponding to them is two.

[0061] Example 3

[0062] The difference between this embodiment and example 1 is:

[0063] Four auxiliary motors 65 are arranged on the upper part of the rotating shaft 64 in equal intervals in the circumferential direction, and the number of magnetic adsorption plates 67, sliding blocks 611 and telescopic rods 66 corresponding to them is four.

[0064] Note: When the number of magnetic adsorption plates 67 increases, the adsorption effect of magnetic biochar is better, but at the same time, the degree of complexity of scraping by the scraping plate 612 is also increased, therefore, the number of magnetic adsorption plates 67 needs to be reasonably set, and the setting parameters in example 1 are the best.

[0065] Example 4

[0066] The difference between this embodiment and example 1 is:

[0067] The electromagnetic iron 25 covers 85% of the bottom area of the SBR reactor 2.

[0068] Embodiment 5

[0069] The embodiment is a method for carbon capture and phosphorus removal with high efficiency, low consumption and high load by contact stabilization, based on the device for carbon capture and phosphorus removal with high efficiency, low consumption and high load in embodiment 1, comprising the following steps:

[0070] S1, water stirring: the sewage is injected into the sewage pool 1, stirred uniformly by the water stirrer 11, and then injected into the SBR reactor 2;

[0071] S2, SBR treatment: the operation mode of the SBR reactor 2 includes a single operation cycle, which includes a contact section, a sedimentation section, a drainage section and a stabilization section;

[0072] S2-1, contact section: first, water is injected within 5 min, and magnetic biochar is added by the biochar feeder 5, so that the sewage and the magnetic biochar are in 15 min non-aeration contact reaction, and the magnetic biochar addition amount is 200 mg / L;

[0073] The preparation method of the magnetic biochar is as follows: one or more of the coconut shell biochar is mixed, mixed with stainless steel balls at a mass ratio of 1:100 in a stainless steel grinding jar, ground, and passed through a 200 mesh screen to obtain a biomass powder, the diameter of the stainless steel balls is less than 3 mm, the biomass powder is mixed with magnetic powder at a mass ratio of 1:3 in a planetary ball mill, the planetary ball mill is operated at a speed of 350 rpm for 11 h, and then washed with Milli-Q water and ethanol alternately for 3 times, and then the supernatant is removed by magnetic separation, and dried at 65°C to obtain the magnetic biochar;

[0074] S2-2, sedimentation section: the electromagnet 25 is opened, and the magnetic field is used to promote the sedimentation of the magnetic biochar and the sludge, and the sedimentation time is 30 min, so as to ensure the efficient separation of the sludge and water in the SBR reactor 2;

[0075] S2-3, drainage section: the water outlet pipe 21 is opened to drain water within 5 min, and the sewage in the SBR reactor 2 is drained to half water level, and the treated sewage is discharged into the denitrification reaction tank 3 for denitrification treatment;

[0076] S2-4, stabilization section: the aeration pipe 23 is opened to aerate the remaining sewage and sludge in the SBR reactor 2 for 50 min, the dissolved oxygen concentration is controlled at 1.6 mg / L, and the reaction stirrer 24 rotates at a speed of 80 rpm, then a part of the sludge is discharged to the anaerobic digestion tank 4 through the sludge discharge pipe 22, the sludge retention time in the SBR reactor 2 is controlled at 1 day, and then S1 and S2 are repeated to treat the next batch of sewage;

[0077] S3, sludge fermentation: control the internal temperature of the anaerobic digester 4 at 37℃, and set the stirring speed at 110 rpm, ferment for 23 days, collect the biogas at the top of the anaerobic digester 4, and then discharge the remaining sludge into the biochar sludge removal device 6;

[0078] S4, magnetic biochar recovery: the remaining sludge is washed and removed by the biochar sludge removal device 6 to obtain the reused magnetic biochar, and the reused magnetic biochar is added to the biochar dosing device 5 through the reflux pipe 51 for reuse.

[0079] Example 6

[0080] The difference between this embodiment and example 5 is that the specific parameter settings of S2-1 to S2-4 in S2 are different.

[0081] S2-1, contact section: first add magnetic biochar through the biochar dosing device 5 while water is flowing in for 6 min, and the magnetic biochar and the wastewater are in a 10 min non-aeration contact reaction, the magnetic biochar dosage is 100 mg / L;

[0082] S2-2, sedimentation section: turn on the electromagnet 25, use the magnetic field to promote the sedimentation of the magnetic biochar and the sludge, the sedimentation time is 10 min, to ensure efficient separation of the sludge and water in the SBR reactor 2;

[0083] S2-3, drainage section: open the water outlet pipe 21 to drain water in 5 min, and discharge the wastewater in the SBR reactor 2 to half water level, and then discharge the treated wastewater into the denitrification reaction tank 3 for denitrification treatment;

[0084] S2-4, stabilization section: open the aeration pipe 23 to aerate the remaining wastewater and sludge in the SBR reactor 2, for 40 min, the dissolved oxygen concentration is controlled at 1.5 mg / L, the reaction stirrer 24 rotates at 60 rpm, then a part of the sludge is discharged to the anaerobic digester 4 through the sludge discharge pipe 22, the sludge retention time in the SBR reactor 2 is controlled at 0.5 days, then the S1 and S2 are repeated to treat the next batch of wastewater.

[0085] Example 7

[0086] The difference between this embodiment and example 5 is that the specific parameter settings of S2-1 to S2-4 in S2 are different.

[0087] S2-1, contact section: first add magnetic biochar through the biochar dosing device 5 while water is flowing in for 8 min, and the magnetic biochar and the wastewater are in a 13 min non-aeration contact reaction, the magnetic biochar dosage is 400 mg / L;

[0088] S2-2, sedimentation section: open the electromagnet 25, use the magnetic field to promote the sedimentation of magnetic biochar and sludge, the sedimentation time is 25 min, to ensure the efficient separation of sludge and water in the SBR reactor 2;

[0089] S2-3, drainage section: open the water outlet pipe 21 to drain water within 8 min, drain the sewage in the SBR reactor 2 to half water level, and discharge the treated sewage into the denitrification reaction tank 3 for denitrification treatment;

[0090] S2-4, stabilization section: open the aeration pipe 23 to aerate the remaining sewage and sludge in the SBR reactor 2 for 45 min, the dissolved oxygen concentration is controlled at 1.8 mg / L, the reaction stirrer 24 rotates at 120 rpm, then a part of sludge is discharged through the sludge discharge pipe 22 to the anaerobic digestion tank 4, the sludge retention time in the SBR reactor 2 is controlled at 0.75 days, then the S1 and S2 are repeated to treat the next batch of sewage.

[0091] Example 8

[0092] The difference between this example and example 5 is that the specific parameter settings of S2-1 to S2-4 in S2 are different.

[0093] S2-1, contact section: first add magnetic biochar through the biochar feeder 5 while water is being added within 10 min, the sewage and the magnetic biochar are contacted for 15 min without aeration, the magnetic biochar dosage is 500 mg / L;

[0094] S2-2, sedimentation section: open the electromagnet 25, use the magnetic field to promote the sedimentation of magnetic biochar and sludge, the sedimentation time is 30 min, to ensure the efficient separation of sludge and water in the SBR reactor 2;

[0095] S2-3, drainage section: open the water outlet pipe 21 to drain water within 10 min, drain the sewage in the SBR reactor 2 to half water level, and discharge the treated sewage into the denitrification reaction tank 3 for denitrification treatment;

[0096] S2-4, stabilization section: open the aeration pipe 23 to aerate the remaining sewage and sludge in the SBR reactor 2 for 50 min, the dissolved oxygen concentration is controlled at 2 mg / L, the reaction stirrer 24 rotates at 150 rpm, then a part of sludge is discharged through the sludge discharge pipe 22 to the anaerobic digestion tank 4, the sludge retention time in the SBR reactor 2 is controlled at 1 day, then the S1 and S2 are repeated to treat the next batch of sewage.

[0097] Note: In examples 5-8, the parameters of each step of S2 in SBR treatment are classified, when the volume of sewage to be treated is small, the parameter combination in example 6 is selected, when the volume of sewage to be treated is large, the parameter combination in example 8 is selected.

[0098] Example 9

[0099] The difference between this example and Example 5 is that the parameters of the preparation method of the magnetic biochar are different.

[0100] The preparation method of the magnetic biochar is as follows: one or more of the rice husk biochar is mixed, and then mixed with stainless steel balls at a mass ratio of 1:100 in a stainless steel grinding tank for grinding, and then sieved through a 200-mesh sieve to obtain biomass powder, the diameter of the stainless steel balls is less than 3 mm, the biomass powder is mixed with magnetic powder at a mass ratio of 1:2 in a planetary ball mill, the planetary ball mill is operated at a speed of 300 rpm for 10 h, then washed with Milli-Q water and ethanol alternately for 3 times, and then the supernatant is removed by magnetic separation, and then dried at 60°C to obtain the magnetic biochar.

[0101] Example 10

[0102] The difference between this example and Example 5 is that the parameters of the preparation method of the magnetic biochar are different.

[0103] The preparation method of the magnetic biochar is as follows: one or more of the sawdust biochar is mixed, and then mixed with stainless steel balls at a mass ratio of 1:100 in a stainless steel grinding tank for grinding, and then sieved through a 200-mesh sieve to obtain biomass powder, the diameter of the stainless steel balls is less than 3 mm, the biomass powder is mixed with magnetic powder at a mass ratio of 1:4 in a planetary ball mill, the planetary ball mill is operated at a speed of 400 rpm for 12 h, then washed with Milli-Q water and ethanol alternately for 3 times, and then the supernatant is removed by magnetic separation, and then dried at 70°C to obtain the magnetic biochar.

[0104] Note: In Example 5 and Example 9, Example 10, the parameter that plays a major role is the mass ratio of biomass powder to magnetic powder, the higher the proportion of magnetic powder, the better the effect of SBR treatment and recovery, but it may inhibit the fermentation of S3 sludge, and the parameters in Example 1 are preferred in combination.

[0105] Example 11

[0106] The difference between this example and Example 5 is that the parameters of the S3 sludge fermentation are different.

[0107] S3 sludge fermentation: the internal temperature of the anaerobic digester 4 is controlled at 36.8°C, and the stirring speed is set at 100 rpm, and the fermentation is carried out for 20 days, the biogas at the top of the anaerobic digester 4 is collected, and then the remaining sludge is discharged into the biochar sludge removal device 6.

[0108] Example 12

[0109] The difference between this embodiment and embodiment 5 is that: S3, the parameter settings in the sludge fermentation are different.

[0110] S3, sludge fermentation: control the internal temperature of the anaerobic digester 4 to 37.2° C., set the stirring speed to 120 rpm, ferment for 25 days, collect the biogas at the top of the anaerobic digester 4, and then discharge the remaining sludge into the biochar desludge device 6.

[0111] Experimental Example 1

[0112] According to the method in Example 5, we conducted multiple experiments (R1 to R3), where R1 was a blank control group without biochar, R2 was a group with only coconut shell biochar added, and R3 was a group with magnetic biochar added (Example 5). The total COD of municipal sewage to be treated was 217 mg / L, the soluble COD was 77 mg / L, the particulate COD was 127 mg / L, and the phosphate concentration was 3.5 mg / L. After the three experimental groups were operated synchronously for 20 days, the average total COD removal rates of each reactor were R1 (45.1%), R2 (46.1%), and R3 (47.1%).

[0113] (37.7%) and R3 (53.7%), the pCOD removal rates were R1 (54.6%), R2 (33.3%) and R3 (54.7%), and the average sCOD removal rates were R1 (30.7%), R2 (44.3%) and R3 (49.9%), respectively. The average organic carbon capture efficiency of R1 during the entire experiment was 41%, the organic carbon capture efficiency of R3 was 48%, and the organic carbon capture efficiency of R2 was only 36%. The phosphate removal rates were R1 (10.7%), R2 (14.3%) and R3 (57.1%), respectively.

[0114] It can be seen that by adding magnetic biochar, the removal rate of phosphate in sewage has been significantly improved, which promotes the adsorption of organic carbon and phosphorus in sewage and ensures stable and efficient carbon capture and phosphorus removal effects.

[0115] Experimental Example 2

[0116] Subsequently, we treated the next batch of municipal sewage according to the method in Example 6, and set up three groups of comparative experiments in the same way. The total COD of municipal sewage was 289 mg / L, the soluble COD was 105 mg / L, the particulate COD was 168 mg / L, and the phosphate concentration was 4.2 mg / L. After running for 30 days, the average total COD removal rates of each reactor were R1 (48.3%), R2 (36.1%), and R3 (63.6%). The average organic carbon capture efficiency of R1 during the entire experimental period was 43.5%, the organic carbon capture efficiency of R3 was 52.7%, and the organic carbon capture efficiency of R2 was only 37.2%. The phosphate removal rates were R1 (17.9%), R2 (20.3%), and R3 (60.6%).

[0117] It can be seen that the same trend as in Experimental Example 1 is reacted in Experimental Example 2, which shows that the device and method of the application can effectively improve the capture efficiency of organic carbon in wastewater, and also has a good removal effect on phosphorus, the sludge settling rate is fast, the energy and material consumption is low, and the wastewater carbon capture and phosphorus removal effect is stable, efficient and low consumption.

Claims

1. A method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method, characterized in that: The method is carried out on the basis of a carbon capture and phosphorus removal device, which comprises a sewage pool (1), an SBR reactor (2) connected to the sewage pool (1), a denitrification reaction pool (3) connected to a water outlet pipe (21) in the middle of the SBR reactor (2), and an anaerobic digestion tank (4) connected to a mud discharge pipe (22) at the bottom of the SBR reactor (2); A water inlet stirrer (11) is provided inside the sewage pool (1), an aeration pipe (23) is provided on one side of the bottom of the SBR reactor (2), a reaction stirrer (24) is provided on the top of the SBR reactor (2), a biochar feeder (5) is provided on one side of the top of the SBR reactor (2), and an electromagnet (25) is provided on the bottom of the SBR reactor (2); A biochar desludging device (6) is provided on one side of the anaerobic digestion tank (4), and a biochar reflux tank (61) provided on the biochar desludging device (6) is connected to the biochar feeder (5) via a reflux pipe (51); The method comprises the following steps: S1, water inlet stirring: inject sewage into the sewage pool (1), stir it evenly through the water inlet stirrer (11), and then inject it into the SBR reactor (2); S2. SBR treatment: A single operation cycle in the operation mode of the SBR reactor (2) includes a contact stage, a sedimentation stage, a drainage stage, and a stabilization stage; S2-1, contact section: first, magnetic biochar is added through the biochar doser (5) while water is introduced within 5 to 10 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 10 to 15 minutes, with the amount of magnetic biochar added being 100 to 500 mg / L; S2-2, sedimentation stage: Turn on the electromagnet (25) and use the magnetic field to promote the sedimentation of magnetic biochar and sludge. The sedimentation time is 10 to 30 minutes to ensure efficient separation of mud and water in the SBR reactor (2); S2-3, drainage section: Open the outlet pipe (21) and drain the water within 5 to 10 minutes, drain the sewage in the SBR reactor (2) to half the water level, and discharge the treated sewage into the denitrification reaction tank (3) for denitrification treatment; S2-4, stabilization stage: open the aeration pipe (23) to aerate the remaining sewage and sludge in the SBR reactor (2) for 40 to 50 minutes, control the dissolved oxygen concentration at 1.5 to 2 mg / L, and rotate the reaction agitator (24) at 60 to 150 rpm. Then, discharge a portion of the sludge to the anaerobic digester (4) through the sludge discharge pipe (22). Control the sludge retention time inside the SBR reactor (2) to 0.5 to 1 day, and then repeat S1 and S2 to treat the next batch of sewage. S3, sludge fermentation: controlling the internal temperature of the anaerobic digester (4) to 37 ± 0.2 ° C, and setting the stirring speed to 100-120 rpm, fermenting for 20-25 days, collecting the biogas at the top of the anaerobic digester (4), and then discharging the remaining sludge into the biochar desludge device (6); S4. Recovery of magnetic biochar: The remaining sludge is cleaned and sludge is removed by a biochar desludging device (6) to obtain recycled magnetic biochar, and the recycled magnetic biochar is added to the biochar feeder (5) through a reflux pipe (51) for reuse.

2. The method for carbon and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: The sewage pool (1) and the SBR reactor (2) are connected via a sewage pipe (12), and a sewage pump (13) is provided in the middle of the sewage pipe (12).

3. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: An air pump (26) is provided at the end of the aeration pipe (23), a water outlet pump (27) is provided in the middle of the water outlet pipe (21), and a mud discharge pump (28) is provided in the middle of the mud discharge pipe (22).

4. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: The upper surface of the electromagnet (25) and the bottom of the SBR reactor (2) are concentric circles, and the coverage area of ​​the electromagnet (25) is greater than 75% of the bottom area of ​​the SBR reactor (2).

5. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: A methane discharge pipe (41) is provided on the top of the anaerobic digestion tank (4).

6. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: The biochar desludging device (6) includes an ultrasonic desludging chamber (62), a main motor (63) is provided on the top of the ultrasonic desludging chamber (62), a rotating shaft (64) is provided at the output end below the main motor (63), a plurality of auxiliary motors (65) are provided at equal intervals in the circumferential direction on the upper part of the rotating shaft (64), a telescopic rod (66) is provided at the output end below the auxiliary motor (65), a magnetic plate (67) is fixedly connected to the end of the telescopic rod (66), and each magnetic plate (67) is vertically connected to the magnetic plate (67). The rotating shaft (64) is provided with a plurality of grooves (641) on the side wall thereof at equal intervals in the vertical direction. Each telescopic rod (66) corresponds to each of the grooves (641) one by one, and the grooves (641) extend to the position of the corresponding magnetic plate (67). The bottom of the telescopic rod (66) is fixedly connected to a fixed block (671) provided at the inner end of the magnetic plate (67). The fixed block (671) slides up and down in the groove (641). The rotating shaft (64) located on both sides of the magnetic plate (67) An auxiliary stirring rod (642) is provided on the outer wall or on the outer wall of the rotating shaft (64) between two adjacent grooves (641), a slot (621) is provided on the upper part of one side wall of the ultrasonic desludging bin (62), the biochar reflux groove (61) slides inside the slot (621), a slider (611) is provided at the bottom of the biochar reflux groove (61), the slider (611) and the slide groove (622) provided at the bottom of the slot (621) are slidably and position-limitedly connected, the biochar reflux groove (61) ) is provided on one side with a scraper (612) for fitting with the bottom of the magnetic plate (67) and scraping off the magnetic biochar, and a hydraulic push rod (68) is provided on the side wall of the ultrasonic desludging bin (62) below the slot (621), and the output end of the hydraulic push rod (68) is fixedly connected to the front end of the bottom of the biochar reflux trough (61), and when the biochar reflux trough (61) slides outward from the slot (621) to the maximum position, the reflux pipe (51) corresponds to the top of the biochar reflux trough (61).

7. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 6, characterized in that: The two sides of the main motor (63) are fixedly connected to the ultrasonic desludging bin (62) through fixed rods (631), there are three auxiliary motors (65), and the corresponding telescopic rods (66) and magnetic plates (67) are both three. An auxiliary stirring rod (642) is provided on each side of the bottom magnetic plate (67), an auxiliary stirring rod (642) is provided on one side of a magnetic plate (67) located in the middle, and three auxiliary stirring rods (642) are provided on the outer wall of the rotating shaft (64) between two adjacent grooves (641) above the top magnetic plate (67).

8. The method for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1, characterized in that: The magnetic biochar preparation method comprises the following steps: mixing one or more of coconut shell, sawdust or rice husk biochars, mixing the mixture with stainless steel balls at a mass ratio of 1:100, loading the mixture into a stainless steel grinding jar, grinding the mixture, and passing the mixture through a 200-mesh sieve to obtain biomass powder, wherein the diameter of the stainless steel balls is less than 3 mm; mixing the biomass powder with magnetic powder at a mass ratio of 1:2-4, loading the mixture into a planetary ball mill, and milling the mixture; operating the planetary ball mill at a speed of 300-400 rpm for 10-12 hours; washing the mixture with Milli-Q water and ethanol alternately three times, removing the supernatant by magnetic separation, and drying the mixture at 60-70° C. to obtain the magnetic biochar.

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