High-efficiency low-consumption high-load device and method for capturing carbon and removing phosphorus by contact stabilization method

Abstract

The invention discloses a high-efficiency low-consumption high-load carbon capture and phosphorus removal device and method by a contact stabilization method, the device comprises a sewage pool, an SBR (sequencing batch reactor) communicated with the sewage pool, a denitrification reaction pool communicated with a water outlet pipe in the middle of the SBR, an anaerobic digester communicated with a sludge discharge pipe at the bottom of the SBR, and a charcoal desliming device arranged on one side of the anaerobic digester. The method comprises the following steps: S1, feeding water and stirring; s2, SBR (sequencing batch reactor) treatment; s3, sludge fermentation; and S4, recovering the magnetic biochar. The magnetic biochar is added into the high-load SBR reactor with stable contact, adsorption of organic carbon and phosphorus in sewage is synchronously promoted, the trapping effect of soluble organic matter is further improved, adsorption of organic carbon and phosphorus in sewage is promoted, and the stable and efficient carbon trapping and phosphorus removing effect is guaranteed.

Description

Technical Field

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

[0002] At present, the 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 emissions. Under the premise of achieving standard discharge of municipal sewage treatment, promoting low-carbon operation of sewage treatment plants through sewage energy recovery has become the focus of attention. The organic carbon in municipal sewage contains rich chemical energy. Efficient capture of organic carbon in the influent is one of the key measures to achieve low-carbon operation of sewage treatment plants. Domestic and foreign researchers have studied sewage organic carbon capture technology, mainly including chemically enhanced primary treatment, high-load membrane separation technology and high-load activated sludge method. Although chemically enhanced primary treatment and high-load membrane separation technology can achieve higher organic carbon capture efficiency, they rely on a large amount of coagulant addition and extremely high investment costs, and have high operating costs and difficulties in large-scale promotion and application.

[0003] The high-load activated sludge process (HRAS) has extremely 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, with low operating costs and good economic benefits; and can effectively remove nitrogen by combining with low-carbon denitrification processes. For example, the Strass sewage treatment plant in Austria adopted a coupling process of HRAS and anaerobic ammonium oxidation, and achieved an energy self-sufficiency rate of 160% in 2013. However, the characteristics of extremely short sludge retention time (SRT) and hydraulic retention time (HRT) limit the process's ability to capture soluble organic matter and remove phosphorus, limiting the promotion and application of the process.

[0004] Biochar is an ideal soluble organic matter adsorbent due to its advantages of good economy, high adsorption efficiency and the fact that it can be produced from biomass waste. However, powdered biochar is difficult to separate from water and often requires centrifugation or filtration. Introducing magnetic Fe3O4 into the biochar matrix to prepare magnetic biochar is an effective solution to this problem. Fe3O4 can also form complexes with phosphates to improve the phosphorus removal effect. Magnetic biochar can be quickly recovered by magnetic separation, thereby achieving simultaneous enhancement of organic carbon capture, phosphorus adsorption and removal, and solid-liquid separation. In addition, the magnetic substances in magnetic biochar will also produce a magnetic effect on microorganisms, further improving the process performance and the subsequent energy resource recovery efficiency of anaerobic digestion of sludge. Therefore, exploring the high-load activated sludge wastewater carbon capture enhancement technology based on magnetic biochar can provide support for the optimization control and promotion and application of the process, which is of great significance for the low-carbon operation of sewage treatment plants. At present, further research is needed on the combined use of magnetic biochar and high-load activated sludge to treat sewage. Summary of the invention

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

[0006] The technical solution of the present invention is:

[0007] A high-efficiency, low-consumption, high-load contact stabilization method carbon capture and phosphorus removal device, comprising a sewage pool, an SBR reactor connected to the sewage pool, a denitrification reaction pool connected to a water outlet pipe in the middle of the SBR reactor, and an anaerobic digestion tank connected to a mud discharge pipe at the bottom of the SBR reactor;

[0008] A water inlet stirrer is provided inside the sewage pool, an aeration pipe is provided on one side of the bottom of the SBR reactor, a reaction stirrer is provided on the top of the SBR reactor, a biochar feeder is provided on one side of the top of the SBR reactor, and an electromagnet is provided on the bottom of the SBR reactor;

[0009] A biochar desludging device is provided at one side of the anaerobic digestion tank, and a biochar reflux trough provided on the biochar desludging device is connected to the biochar dosing device through a reflux pipe.

[0010] Furthermore, the sewage pool and the SBR reactor are connected via a sewage pipe, and a sewage pump is provided in the middle of the sewage pipe.

[0011] Note: Through continuous stirring of the sewage pool, the particulate matter in the sewage can enter the SBR reactor evenly.

[0012] Furthermore, an air pump is provided at the end of the aeration pipe, a water outlet pump is provided in the middle of the water outlet pipe, and a mud discharge pump is provided in the middle of the mud discharge pipe.

[0013] Furthermore, 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 bottom area of ​​the SBR reactor.

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

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

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

[0017] Furthermore, the biochar desludging device includes an ultrasonic desludging bin, a main motor is provided on the top of the ultrasonic desludging bin, a rotating shaft is provided at the output end below the main motor, a plurality of auxiliary motors are provided at equal intervals in the circumferential direction on the upper part of the rotating shaft, a telescopic rod is provided at the output end below the auxiliary motor, a magnetic plate is fixedly connected to the end of the telescopic rod, each of the magnetic plates is arranged at equal intervals in the vertical direction, a plurality of grooves are provided on the side wall of the rotating shaft, each telescopic rod corresponds to each of the grooves one by one, and the grooves extend to the corresponding positions of the magnetic plates, the bottom of the telescopic rod is fixedly connected to a fixed block provided at the inner end of the magnetic plate, the fixed block slides up and down in the groove, and the fixed block located on both sides of the magnetic plate Auxiliary stirring rods are provided on the outer wall of the rotating shaft, or on the outer wall of the rotating shaft between two adjacent grooves, a groove is provided on the upper part of one side wall of the ultrasonic desludging bin, the biochar reflux groove slides inside the groove, a sliding block is provided at the bottom of the biochar reflux groove, the sliding block slides and is limitedly connected to the sliding groove provided at the bottom of the groove, a scraper is provided on one side of the biochar reflux groove for fitting with the bottom of the magnetic suction plate and scraping off the magnetic biochar, a hydraulic push rod is provided on the side wall of the ultrasonic desludging bin below the groove, the output end of the hydraulic push rod is fixedly connected to the front end of the bottom of the biochar reflux groove, and when the biochar reflux groove slides out of the groove to the maximum position, the reflux pipe corresponds to the top of the biochar reflux groove.

[0018] Description: The magnetic biochar after anaerobic digestion can be quickly cleaned and desludged by the biochar desludging device and reused in time.

[0019] Furthermore, the two sides of the main motor are fixedly connected to the ultrasonic desludging bin through fixing rods, there are three auxiliary motors, and the corresponding telescopic rods and magnetic plates are three. One auxiliary stirring rod is provided on each side of the bottom magnetic plate, one auxiliary stirring rod is provided on one side of a magnetic plate located in the middle, and three auxiliary stirring rods are provided on the outer wall of the rotating shaft between two adjacent grooves above the top magnetic plate.

[0020] Note: By optimizing and adjusting the number of magnetic suction plates, the cleaning efficiency of magnetic biochar is ensured while the recovery speed is improved.

[0021] A method for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method is based on any one of the above-mentioned devices for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method, comprising the following steps:

[0022] S1, water inlet stirring: inject sewage into the sewage pool, stir it evenly with the water inlet stirrer, and then inject it into the SBR reactor;

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

[0024] S2-1, contact stage: first, magnetic biochar is added through the biochar doser while the water is entering within 5 to 10 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 10 to 15 minutes, and the amount of magnetic biochar added is 100 to 500 mg / L;

[0025] S2-2, sedimentation stage: turn on the electromagnet 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;

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

[0027] S2-4, stable stage: open the aeration pipe to aerate the remaining sewage and sludge in the SBR reactor for 40-50 minutes, control the dissolved oxygen concentration at 1.5-2 mg / L, and the speed of the reaction agitator is 60-150 rpm. Then, discharge a part of the sludge to the anaerobic digester through the sludge discharge pipe. Control the sludge retention time inside the SBR reactor to 0.5-1 day, and then repeat S1 and S2 to treat the next batch of sewage;

[0028] S3, sludge fermentation: control the internal temperature of the anaerobic digester to 37 ± 0.2 ° C, set the stirring speed to 100-120 rpm, ferment for 20-25 days, collect the biogas at the top of the anaerobic digester, and then discharge the remaining sludge into the biochar desludge device;

[0029] S4. Recovery of magnetic biochar: The remaining sludge is washed and removed through a biochar desludging device to obtain the reused magnetic biochar, and the reused magnetic biochar is added to the biochar doser through a reflux pipe for reuse.

[0030] Furthermore, the preparation method of the magnetic biochar is: after mixing one or more of coconut shell, sawdust or rice husk biochar, mix it with stainless steel balls at a mass ratio of 1:100, put it into a stainless steel grinding jar, grind it, and pass it through a 200-mesh sieve to obtain biomass powder, wherein the diameter of the stainless steel balls is less than 3 mm, mix the biomass powder and magnetic powder at a mass ratio of 1:2-4, put it into a planetary ball mill for ball milling, and run the planetary ball mill at a speed of 300-400 rpm for 10-12 hours. After taking it out, wash it alternately with Milli-Q water and ethanol for 3 times, and then remove the supernatant by magnetic separation, and dry it at 60-70°C to obtain magnetic biochar.

[0031] Description: By adding magnetic biochar into a high-load contact-stable SBR reactor, the magnetic biochar can not only serve as a site for microorganisms to attach, but also directly form a complex with phosphorus, thereby simultaneously promoting the adsorption of organic carbon and phosphorus in wastewater.

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

[0033] (1) The device and method for carbon and phosphorus removal by high-efficiency, low-consumption, high-load contact stability of the present invention adds magnetic biochar to a high-load contact stability SBR reactor. The magnetic biochar can not only serve as an attachment site for microorganisms, but also directly form a complex with phosphorus, thereby simultaneously promoting the adsorption of organic carbon and phosphorus in sewage. Under a certain stirring action, the reaction flow field can be evenly distributed, thereby improving the contact efficiency of sewage, sludge and magnetic biochar, further enhancing the capture effect of soluble organic matter, promoting the adsorption of organic carbon and phosphorus in sewage, and ensuring stable and efficient carbon and phosphorus capture effects.

[0034] (2) The device and method for carbon and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method of the present invention adopts an external electromagnet. When the SBR reactor runs to the sedimentation stage, the electromagnet is turned on to promote the rapid sedimentation of the magnetic biochar. Due to the adsorption effect of the biochar on the sludge, the sludge can be rapidly precipitated and the sludge sedimentation efficiency can be improved simultaneously, thereby achieving efficient retention of particulate and colloidal organic carbon, reducing the hydraulic retention time, and greatly improving the reactor's ability to resist shock loads.

[0035] (3) The device and method for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method of the present invention can perform anaerobic digestion on the mixture of discharged magnetic biochar and sludge, and greatly increase the biogas production, shorten the start-up time of the anaerobic digester, and the methane content in the biogas is higher, thereby improving the efficiency of wastewater energy and resource utilization. The magnetic biochar after anaerobic digestion can be reused after simple cleaning. The biochar desludging device is simple in structure, easy to operate, and stable in operation, ultimately achieving an effective improvement in the capture efficiency of organic carbon in wastewater. At the same time, it also has a good removal effect on phosphorus, a fast sludge settling rate, and low energy and material consumption, thereby achieving a stable, high-efficiency, and low-consumption wastewater carbon capture and phosphorus removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the overall structure of a device for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to the present invention;

[0037] Figure 2 This is a front view of a device for carbon capture and phosphorus removal using a high-efficiency, low-consumption, high-load contact stabilization method according to the present invention;

[0038] Figure 3 It is a schematic structural diagram of a biochar desludging device in a device for carbon and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method according to the present invention;

[0039] Figure 4 It is a schematic diagram of the internal structure of a biochar desludging device in a device for carbon and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method according to the present invention;

[0040] Figure 5 It is a side view of a biochar desludging device in a device for carbon and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method according to the present invention;

[0041] Figure 6 It is a front view of a biochar desludging device in a high-efficiency, low-consumption, high-load contact stabilization method carbon and phosphorus removal device of the present invention, omitting the ultrasonic desludging bin;

[0042] Figure 7 It is a front view of a biochar desludging device in a device for carbon and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method, in which the ultrasonic desludging bin is omitted and the biochar reflux tank is moved;

[0043] Figure 8 It is a schematic diagram of the connection structure between the rotating shaft and the magnetic suction plate of the biochar desludging device in the device for carbon and phosphorus removal by the high-efficiency, low-consumption and high-load contact stabilization method of the present invention.

[0044] Among them, 1-sewage tank, 11-water inlet agitator, 12-sewage pipe, 13-sewage pump, 2-SBR reactor, 21-outlet pipe, 22-sludge pipe, 23-aeration pipe, 24-reaction agitator, 25-electromagnet, 26-air pump, 27-outlet pump, 28-sludge pump, 3-denitrification reaction tank, 4-anaerobic digester, 41-biogas discharge pipe, 5-biochar dosing device, 51-return pipe, 6-biochar desludge device, 61-biochar return trough, 611-slider, 612-scraper, 62-ultrasonic desludge bin, 621-groove, 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 suction plate, 671-fixed block, 68-hydraulic push rod. DETAILED DESCRIPTION

[0045] Example 1

[0046] like Figure 1 As shown, a highly efficient, low-consumption, high-load contact stabilization method carbon capture and phosphorus removal device 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;

[0047] like Figure 2 As shown, a water inlet agitator 11 is provided inside the sewage pool 1, and the sewage pool 1 and the SBR reactor 2 are connected through a sewage pipe 12, and a sewage pump 13 is provided in the middle of the sewage pipe 12;

[0048] like Figure 1 and 2 As shown, an aeration pipe 23 is provided at one side of the bottom of the SBR reactor 2, a reaction stirrer 24 is provided at the top of the SBR reactor 2, a biochar feeder 5 is provided at one side of the top of the SBR reactor 2, and the biochar feeder 5 is a commercially available small-sized fish feed automatic feeding device, an electromagnet 25 is provided at the bottom of the SBR reactor 2, the upper surface of the electromagnet 25 is a concentric circle with the bottom of the SBR reactor 2, and the coverage area of ​​the electromagnet 25 is 80% of the bottom area of ​​the SBR reactor 2, 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;

[0049] like Figure 2 and 3 As shown, a biogas discharge pipe 41 is provided on the top of the anaerobic digestion tank 4, 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 through a reflux pipe 51;

[0050] like Figures 3 to 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 in the circumferential direction on the upper part of the rotating shaft 64, and 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, and each magnetic plate 67 is arranged at equal intervals in the vertical direction, and 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 attraction 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 attraction 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 attraction 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 attraction plate 67, an auxiliary stirring rod 642 is provided on one side of a magnetic attraction 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 attraction plate 67;

[0051] like Figure 3 , 5 As shown in Figure 8, a slot 621 is provided on the upper part of one side wall of the ultrasonic desludging bin 62, and the biochar reflux groove 61 slides inside the slot 621. A slider 611 is provided at the bottom of the biochar reflux groove 61, and the slider 611 slides and is limitedly connected with the slide groove 622 provided at the bottom of the slot 621. A scraper 612 is provided on one side of the biochar reflux groove 61 for fitting with the bottom of the magnetic suction 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 groove 61. When the biochar reflux groove 61 slides out of the slot 621 to the maximum position, the reflux pipe 51 corresponds to the top of the biochar reflux groove 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 are both 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 of 15% of the reactor height.

[0053] Working principle:

[0054] The specific working principle of the biochar desludging device 6 is briefly described below.

[0055] When in use, the sludge containing magnetic biochar is injected into the ultrasonic desludging bin 62, and clean water is added thereto, the amount of clean water added is 3 to 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 to 1200W, and ultrasonic treatment is performed. At the same time, the main motor 63 is turned on to drive the rotating shaft 64 to rotate, so that the magnetic biochar that falls off during ultrasonic cleaning is magnetically adsorbed on the bottom of the magnetic absorption plate 67, and one magnetic absorption plate 67 is scraped every 5 minutes;

[0056] The scraping method is as follows: the auxiliary motor 65 above the corresponding magnetic plate 67 is turned on, so that the magnetic plate 67 is driven to rotate and move upward through the telescopic rod 66 until it moves upward to the horizontal plane where the top of the corresponding scraper 612 is located, and then the hydraulic push rod 68 is turned on to drive the biochar reflux trough 61 to slide into the ultrasonic desludging bin 62. Figure 6 The state becomes Figure 7 In the middle state, the biochar reflux groove 61 is located at the bottom of the magnetic attraction plate 67, and the attached magnetic biochar is scraped off and dropped into the biochar reflux groove 61 by contact with the scraper 612 during rotation, and then the biochar reflux groove 61 is reset;

[0057] The magnetic biochar attached to each magnetic suction plate 67 is scraped off in turn, and the magnetic biochar is introduced into the biochar feeder 5 through the reflux pipe 51 .

[0058] Example 2

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

[0060] Two auxiliary motors 65 are provided at equal intervals in the circumferential direction on the upper part of the rotating shaft 64 , and correspondingly, the number of the magnetic attraction plate 67 , the sliding block 611 and the telescopic rod 66 are all two.

[0061] Example 3

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

[0063] Four auxiliary motors 65 are provided at equal intervals in the circumferential direction on the upper part of the rotating shaft 64 , and correspondingly, the number of the magnetic attraction plate 67 , the sliding block 611 and the telescopic rod 66 are all four.

[0064] Note: When the number of magnetic plates 67 increases, the adsorption effect on magnetic biochar is better, but it also increases the complexity of scraping by the scraper 612. Therefore, the number of magnetic plates 67 needs to be reasonably set, and the setting parameters in Example 1 are optimal.

[0065] Example 4

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

[0067] The coverage area of ​​the electromagnet 25 is 85% of the bottom area of ​​the SBR reactor 2 .

[0068] Example 5

[0069] This embodiment is a method for capturing carbon and removing phosphorus by a high-efficiency, low-consumption, high-load, contact-stabilized method, based on a device for capturing carbon and removing phosphorus by a high-efficiency, low-consumption, high-load, contact-stabilized method in Example 1, comprising the following steps:

[0070] 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;

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

[0072] S2-1, contact stage: first, magnetic biochar is added through the biochar doser 5 while the water is introduced within 5 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 15 minutes, and the amount of magnetic biochar added is 200 mg / L;

[0073] The preparation method of magnetic biochar is as follows: after mixing one or more of coconut shell biochars, mix them with stainless steel balls at a mass ratio of 1:100, put them into a stainless steel grinding jar, grind them, pass through a 200-mesh sieve to obtain biomass powder, the diameter of the stainless steel balls is less than 3 mm, mix the biomass powder and magnetic powder at a mass ratio of 1:3, put them into a planetary ball mill for ball milling, run the planetary ball mill at a speed of 350 rpm for 11 hours, take them out and wash them alternately with Milli-Q water and ethanol for 3 times, then remove the supernatant by magnetic separation, and dry them at 65°C to obtain magnetic biochar;

[0074] S2-2, sedimentation stage: turn on the electromagnet 25, use the magnetic field to promote the sedimentation of magnetic biochar and sludge, the sedimentation time is 30 minutes, so as to ensure the efficient separation of mud and water in the SBR reactor 2;

[0075] S2-3, drainage stage: open the outlet pipe 21 to drain water within 5 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;

[0076] S2-4, stable stage: open the aeration pipe 23 to aerate the remaining sewage and sludge in the SBR reactor 2 for 50 minutes, control the dissolved oxygen concentration at 1.6 mg / L, and the speed of the reaction agitator 24 is 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 inside the SBR reactor 2 is controlled to 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 to 37°C, set the stirring speed to 110rpm, ferment for 23 days, collect the biogas at the top of the anaerobic digester 4, and then discharge the remaining sludge into the biochar desludge device 6;

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

[0079] Example 6

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

[0081] S2-1, contact stage: first, magnetic biochar is added through the biochar doser 5 while the water is introduced within 6 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 10 minutes, and the dosage of the magnetic biochar is 100 mg / L;

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

[0083] S2-3, drainage stage: open the outlet pipe 21 to drain water within 5 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;

[0084] S2-4, stabilization stage: open the aeration pipe 23 to aerate the remaining sewage and sludge in the SBR reactor 2 for 40 minutes, control the dissolved oxygen concentration at 1.5 mg / L, and the speed of the reaction agitator 24 is 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 inside the SBR reactor 2 is controlled to 0.5 days, and then S1 and S2 are repeated to treat the next batch of sewage.

[0085] Example 7

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

[0087] S2-1, contact stage: first, magnetic biochar is added through the biochar doser 5 while the water is introduced within 8 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 13 minutes, and the amount of magnetic biochar added is 400 mg / L;

[0088] S2-2, sedimentation stage: turn on the electromagnet 25, use the magnetic field to promote the sedimentation of magnetic biochar and sludge, the sedimentation time is 25 minutes, so as to ensure the efficient separation of mud and water in the SBR reactor 2;

[0089] S2-3, drainage section: open the outlet pipe 21 to drain water within 8 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;

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

[0091] Example 8

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

[0093] S2-1, contact stage: first, magnetic biochar is added through the biochar doser 5 while the water is introduced within 10 minutes, and the sewage and the magnetic biochar are contacted and reacted without aeration for 15 minutes, and the amount of magnetic biochar added is 500 mg / L;

[0094] S2-2, sedimentation stage: turn on the electromagnet 25, use the magnetic field to promote the sedimentation of magnetic biochar and sludge, the sedimentation time is 30 minutes, so as to ensure the efficient separation of mud and water in the SBR reactor 2;

[0095] S2-3, drainage stage: open the outlet pipe 21 to drain water within 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;

[0096] S2-4, stabilization stage: open the aeration pipe 23 to aerate the remaining sewage and sludge in the SBR reactor 2 for 50 minutes, control the dissolved oxygen concentration at 2 mg / L, and the speed of the reaction agitator 24 is 150 rpm. Then, a part of the sludge is discharged to the anaerobic digester 4 through the sludge discharge pipe 22. The sludge retention time inside the SBR reactor 2 is controlled to 1 day, and then S1 and S2 are repeated to treat the next batch of sewage.

[0097] Note: In Examples 5 to 8, we grade the parameters of each step of the SBR treatment in S2. 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 embodiment and embodiment 5 is that the parameters of the preparation method of magnetic biochar are different.

[0100] The preparation method of magnetic biochar is as follows: after mixing one or more types of rice husk biochar, mix them with stainless steel balls at a mass ratio of 1:100, put them into a stainless steel grinding jar for grinding, and pass them through a 200-mesh sieve to obtain biomass powder. The diameter of the stainless steel balls is less than 3 mm. The biomass powder and magnetic powder are mixed at a mass ratio of 1:2 and put into a planetary ball mill for ball milling. The planetary ball mill is operated at a speed of 300 rpm for 10 hours. After taking out, it is washed alternately with Milli-Q water and ethanol for 3 times, and then the supernatant is removed by magnetic separation, and then dried at 60°C to obtain magnetic biochar.

[0101] Example 10

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

[0103] The preparation method of magnetic biochar is as follows: after mixing one or more of the sawdust biochars, the mixture is mixed with stainless steel balls at a mass ratio of 1:100, and the mixture is put into a stainless steel grinding jar for grinding, and passed through a 200-mesh sieve to obtain biomass powder, wherein the diameter of the stainless steel balls is less than 3 mm. The biomass powder and magnetic powder are mixed at a mass ratio of 1:4 and put into a planetary ball mill for ball milling. The planetary ball mill is operated at a speed of 400 rpm for 12 hours. After being taken out, the mixture is washed alternately with Milli-Q water and ethanol for 3 times, and then the supernatant is removed by magnetic separation, and the mixture is dried at 70°C to obtain magnetic biochar.

[0104] Note: In Examples 5, 9 and 10, the parameter that plays a major influencing factor is the mass ratio of biomass powder to magnetic powder. When the proportion of magnetic powder is higher, the effect on SBR treatment and recovery is better, but it may have an inhibitory effect on S3 sludge fermentation. Considering all the parameters in Example 1, the parameters in Example 1 are preferred.

[0105] Embodiment 11

[0106] The difference between this embodiment and embodiment 5 is that: S3, the parameter settings in the sludge fermentation are different.

[0107] S3, sludge fermentation: control the internal temperature of the anaerobic digester 4 to 36.8°C, set the stirring speed to 100 rpm, ferment for 20 days, collect the biogas at the top of the anaerobic digester 4, and then discharge the remaining sludge into the biochar desludge 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 120rpm, 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, and R3 was a group with magnetic biochar (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 run synchronously for 20 days, the average total COD removal rates of each reactor were R1 (45.1%), R2 (46.7%), and R3 (44.3%).

[0113] (37.7%) and R3 (53.7%), the pCOD removal rates were R1 (54.6%), R2 (33.3%) and R3 (54.7%), the average sCOD removal rates were R1 (30.7%), R2 (44.3%) and R3 (49.9%), and 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] Then 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 30 days of operation, 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 experiment 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%, and the phosphate removal rates were R1 (17.9%), R2 (20.3%) and R3 (60.6%).

[0117] It can be seen that Experimental Example 2 reflects the same trend as Experimental Example 1, indicating that the device and method of the present invention can effectively improve the capture efficiency of organic carbon in sewage, and at the same time have a good removal effect on phosphorus, with a fast sludge settling rate and low energy and material consumption, achieving a stable, efficient and low-consumption sewage carbon capture and phosphorus removal effect.

Claims

1. A device for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method, characterized in that: It 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 pool (4) connected to a mud discharge pipe (22) at the bottom of the SBR reactor (2); The sewage pool (1) is provided with a water inlet stirrer (11), the bottom side of the SBR reactor (2) is provided with an aeration pipe (23), the top of the SBR reactor (2) is provided with a reaction stirrer (24), the top side of the SBR reactor (2) is provided with a biochar feeder (5), and the bottom of the SBR reactor (2) is provided with an electromagnet (25); A biochar desludging device (6) is provided on one side of the anaerobic digestion tank (4), and a biochar reflow trough (61) provided on the biochar desludging device (6) is connected to the biochar dosing device (5) via a reflow pipe (51).

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

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

6. The device for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load contact stabilization method according to claim 1 is characterized in that: The biochar desludging device (6) comprises an ultrasonic desludging bin (62), a main motor (63) is provided at the top of the ultrasonic desludging bin (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 circumferentially 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), a magnetic attraction plate (67) is fixedly connected to the end of the telescopic rod (66), and each of the magnetic attraction plates (67) is vertically spaced. The rotating shaft (64) is provided with a plurality of grooves (641) on the side wall thereof at equal intervals in the vertical direction, and each telescopic rod (66) corresponds to each of the grooves (641) one by one, and the grooves (641) extend to the corresponding position of the magnetic attraction plate (67), and the bottom of the telescopic rod (66) is fixedly connected to a fixing block (671) provided at the inner end of the magnetic attraction plate (67), and the fixing block (671) slides up and down in the groove (641), and the rotating shaft (64) located on both sides of the magnetic attraction 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 groove (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 groove (621); a slider (611) is provided at the bottom of the biochar reflux groove (61); the slider (611) slides and is limitedly connected to a slide groove (622) provided at the bottom of the groove (621); the biochar reflux groove (61 ) is provided with a scraper (612) on one side for fitting with the bottom of the magnetic suction 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 groove (61), and when the biochar reflux groove (61) slides outward from the slot (621) to the maximum position, the reflux pipe (51) corresponds to the top of the biochar reflux groove (61).

7. The device for carbon capture and phosphorus removal by high efficiency, low consumption and high load contact stabilization method according to claim 6 is characterized in that: Both sides of the main motor (63) are fixedly connected to the ultrasonic desludging bin (62) via fixing rods (631), there are three auxiliary motors (65), and correspondingly there are three telescopic rods (66) and three magnetic plates (67). 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. A method for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load, contact-stable method, based on the device for carbon capture and phosphorus removal by a high-efficiency, low-consumption, high-load, contact-stable method according to any one of claims 1 to 7, characterized in that: The following steps are involved: 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: In the operation mode of the SBR reactor (2), a single operation cycle includes a contact stage, a sedimentation stage, a drainage stage and a stabilization stage; S2-1, contact stage: 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, and the amount of magnetic biochar added is 100 to 500 mg / L; S2-2, sedimentation stage: turning on the electromagnet (25) to use the magnetic field to promote the sedimentation of the magnetic biochar and the sludge. The sedimentation time is 10 to 30 minutes to ensure efficient separation of the sludge and water in the SBR reactor (2); S2-3, drainage stage: open the outlet pipe (21) to drain 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 digestion tank (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, 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 washed and sludge is removed by a biochar desludging device (6) to obtain reusable magnetic biochar, and the reusable magnetic biochar is added to the biochar feeder (5) through a reflux pipe (51) for reuse.

9. The device for carbon capture and phosphorus removal by high efficiency, low consumption and high load contact stabilization method according to claim 8 is characterized in that: The preparation method of the magnetic biochar is as follows: after mixing one or more of coconut shell, sawdust or rice husk biochar, the mixture is mixed with stainless steel balls at a mass ratio of 1:100, and then mixed in a stainless steel grinding jar for grinding, and then passed through a 200-mesh sieve to obtain biomass powder, wherein the diameter of the stainless steel balls is less than 3 mm, and the biomass powder and magnetic powder are mixed at a mass ratio of 1:2-4 and then mixed in a planetary ball mill for ball milling, and the planetary ball mill is operated at a speed of 300-400 rpm for 10-12 hours, and then taken out and washed alternately with Milli-Q water and ethanol for 3 times, and then the supernatant is removed by magnetic separation, and then dried at 60-70°C to obtain magnetic biochar.

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