Comprehensive membrane sludge treatment equipment and sludge treatment method

Abstract

The invention discloses comprehensive membrane sludge treatment equipment and a sludge treatment method for recycling and energy regeneration of sludge, an anaerobic dynamic membrane bioreactor is combined with an electrochemical membrane filtration phosphorus in-situ crystallization device, sludge and sludge liquid are treated and recycled by means of a membrane separation technology, biogas generated by digestion is collected, and the biogas is recycled and recycled. The membrane effluent is subjected to phosphorus resource recovery and carbon source reutilization, so that recycling and energy regeneration of sludge are realized, the polarity of the first electrode is controlled to be positive, the polarity of the second electrode is controlled to be negative, so that crystal precipitates are generated in the cathode membrane and nearby the cathode membrane, and part of the crystal precipitates enter a crystal precipitation region under the action of gravity; and controlling the polarities of the first electrode and the second electrode to reverse for 1-5 minutes every 6-8 hours, so that crystal precipitates attached to the cathode film fall off and enter a crystal precipitation area, and the cathode film is automatically cleaned in situ.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge resource utilization, and relates to a comprehensive membrane sludge treatment device and a sludge treatment method for sludge resource conversion into energy. Background Art

[0002] Anaerobic dynamic membrane bioreactor (AnDMBR) devices produce a large amount of pollutant-rich and phosphorus-rich sludge liquid during anaerobic digestion of sludge. If it is directly returned to the front end of the sewage treatment process without treatment, it will generate a large shock load, thereby affecting the stable operation of the sewage treatment plant. In addition, conventional AnDMBR devices usually have difficulty in resource utilization of phosphorus in the sludge liquid, which will lead to insufficient resource utilization and waste of resources. Therefore, the sludge liquid produced by the AnDMBR device needs further treatment. Therefore, it is necessary to develop a device that can realize the resource and energy utilization of sludge. Summary of the Invention

[0003] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a comprehensive membrane sludge treatment equipment and sludge treatment method for sludge resource and energy conversion, combining an anaerobic dynamic membrane bioreactor with an electrochemical membrane filtration phosphorus in situ crystallization device, using membrane separation technology to treat and reuse sludge and sludge liquid, collecting the biogas produced by digestion, and recovering phosphorus resources and reusing carbon sources in the membrane effluent, thereby realizing the resource and energy conversion of sludge.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A first aspect of the present invention provides a comprehensive membrane treatment device, comprising an anaerobic dynamic membrane bioreactor and an electrochemical membrane filtration phosphorus in situ crystallization device;

[0006] The anaerobic dynamic membrane bioreactor is used for anaerobic digestion and concentration separation of sludge. The anaerobic dynamic membrane bioreactor is a split structure, which includes a main reaction zone and a dynamic membrane zone connected by a sludge circulation pipeline; the side of the main reaction zone is provided with a mud inlet, the top is provided with a first biogas outlet, and an agitator is provided inside; the top of the dynamic membrane zone is provided with a second biogas outlet and a membrane water outlet, the bottom is provided with a mud outlet, and a dynamic membrane assembly is integrated inside; the dynamic membrane assembly includes a plurality of flat membranes arranged at equal distances, the flat membranes are provided with an outlet connected to the membrane water outlet, and the bottom of the dynamic membrane assembly is provided with a biogas circulation pipeline connected to the biogas;

[0007] The electrochemical membrane filtration phosphorus in-situ crystallization device is used to perform phosphorus in-situ crystallization on the membrane effluent from the dynamic membrane area, and the electrochemical membrane filtration phosphorus in-situ crystallization device is connected to the membrane outlet of the dynamic membrane area; the electrochemical membrane filtration phosphorus in-situ crystallization device includes a crystallization reaction zone and a crystal precipitation zone arranged above and below; an electrochemical membrane assembly connected to a power supply is provided in the crystallization reaction zone, and the electrochemical membrane assembly includes a plurality of anode plates and a plurality of cathode membranes arranged at equal intervals, a cathode membrane is provided between two adjacent anode plates, and each cathode membrane is provided with a cathode membrane outlet; a membrane outlet connected to the cathode membrane outlet is provided above the crystallization reaction zone; the crystal precipitation zone is a conical structure, and a discharge port is provided at the bottom; the anode plate is connected to the first electrode of a power supply, and the cathode membrane is connected to the second electrode of the power supply, so that the The polarity of the first electrode is positive and the polarity of the second electrode is negative, so as to produce crystal precipitation on the cathode membrane and its vicinity, and part of the crystal precipitation enters the crystal precipitation area for recovery under the action of gravity; the polarity of the first electrode and the second electrode is reversed for 1 to 5 minutes every six to eight hours. During the polarity reversal, the membrane outlet water of the dynamic membrane area is stopped from being sent to the crystallization reaction area, and the polarity of the first electrode is reversed from positive to negative, and the polarity of the second electrode is reversed from negative to positive, so that the crystal precipitation attached to the cathode membrane falls off and enters the crystal precipitation area for recovery and the cathode membrane is automatically cleaned in situ. After the polarity reversal is completed, the membrane outlet water of the dynamic membrane area continues to be sent to the crystallization reaction area, so that the polarity of the first electrode is positive and the polarity of the second electrode is negative, so as to continue to produce crystal precipitation on the cathode membrane and its vicinity.

[0008] Preferably, the cathode membrane is made of porous conductive material, which includes titanium mesh and stainless steel mesh. The anode plate is made of corrosion-resistant conductive material, which includes platinum electrode, platinum-titanium electrode and tin-antimony electrode. The titanium mesh is 100-400 mesh. The liquid level of the electrochemical membrane filtration phosphorus in-situ crystallization device is 26-30 cm. The membrane flux of the electrochemical membrane filtration phosphorus in-situ crystallization device is 9-15 L / (m 2 h), the current density of the power supply is 2-16A / m 2 The distance between adjacent cathode films and anode plates is 1 to 3 cm, so that the polarity of the first electrode and the second electrode is reversed for three minutes every six hours.

[0009] Preferably, the current density is 6-10A / m 2 The titanium mesh is 300 mesh, and the distance between adjacent cathode membranes and anode plates is 2 cm.

[0010] Preferably, the inclination angle of the crystal precipitation zone is set to 50-70°.

[0011] Preferably, the volume ratio of the dynamic membrane zone to the main reaction zone is 1:6 to 1:9.

[0012] Preferably, the sludge circulation pipeline includes a first circulation pipeline and a second circulation pipeline respectively connecting the main reaction zone and the dynamic membrane zone, and a sludge pump is provided on the second circulation pipeline.

[0013] The second aspect of the present invention provides a sludge treatment method for the integrated membrane treatment device according to the first aspect of the present invention, comprising:

[0014] The sludge is sent to the main reaction zone of the anaerobic dynamic membrane bioreactor for digestion;

[0015] The digested sludge in the main reaction zone is sent to the dynamic membrane zone for concentration and separation;

[0016] Returning the concentrated sludge from the dynamic membrane zone to the main reaction zone for re-digestion;

[0017] sending the membrane effluent of the dynamic membrane zone into the crystallization reaction zone of the electrochemical membrane filtration phosphorus in-situ crystallization device;

[0018] Controlling the polarity of the first electrode to be positive and the polarity of the second electrode to be negative to generate crystal precipitation on the cathode film and its vicinity, with part of the crystal precipitation entering the crystal precipitation zone under the action of gravity;

[0019] The polarity of the first electrode and the second electrode is controlled to be reversed for 1 to 5 minutes every six to eight hours. During the polarity reversal, the membrane outlet water of the dynamic membrane area is controlled to stop being fed into the crystallization reaction area. The polarity of the first electrode is controlled to be reversed from positive to negative, and the polarity of the second electrode is controlled to be reversed from negative to positive, so that the crystal precipitate attached to the cathode membrane falls off and enters the crystal precipitation area and the cathode membrane is automatically cleaned in situ. After the polarity reversal is completed, the membrane outlet water of the dynamic membrane area is controlled to continue being fed into the crystallization reaction area. The polarity of the first electrode is controlled to be positive and the polarity of the second electrode is controlled to be negative, so that the crystal precipitate continues to be generated on the cathode membrane and in the vicinity thereof.

[0020] The crystal precipitate entering the crystal precipitation zone is recovered.

[0021] Preferably, the method further comprises controlling the membrane flux of the electrochemical membrane filtration phosphorus in situ crystallization device to be 9 to 15 L / (m 2 h), controlling the current density of the power supply to be 2-16A / m 2 , and controlling the liquid level of the electrochemical membrane filtration phosphorus in-situ crystallization device to 26~30 cm, and controlling the polarity of the first electrode and the second electrode to reverse for three minutes every six hours.

[0022] Preferably, the method further comprises controlling the membrane flux to be 12 L / (m 2 h), controlling the current density to 8 A / m2 .

[0023] Preferably, the method further comprises collecting biogas generated by sludge digestion, and returning the effluent of the electrochemical membrane filtration phosphorus in situ crystallization device to the front end as a supplementary carbon source.

[0024] The present invention has the following beneficial effects: 1. This invention combines an anaerobic dynamic membrane bioreactor with an electrochemical membrane filtration phosphorus in situ crystallization device. In the AnDMBR device, the dynamic membrane solid-liquid separation effect is used to decouple the sludge HRT (hydraulic retention time) and SRT (solid residence time), intercepting the solid phase and increasing the concentration of functional microorganisms in the reaction system, thereby enhancing the system's organic matter digestion and biogas recovery performance. 2. The effluent from the anaerobic dynamic membrane of the present invention is rich in nitrogen and phosphorus elements and enters the downstream electrochemical membrane filtration phosphorus recovery device. The membrane filtration technology enhances material mass transfer, achieving in-situ crystallization and precipitation of resource minerals such as struvite. The organic matter components in the membrane effluent are biodegradable through the electrochemical reduction of the cathode membrane, and can be used as a supplementary carbon source in the anoxic section of the sewage treatment. The lower part of the device is a crystal precipitation area, which is convenient for collecting crystals falling off the cathode surface and can realize automatic cleaning of the electrochemical membrane. 3. This invention, based on an anaerobic dynamic membrane bioreactor, couples an electrochemical membrane filtration phosphorus in-situ crystallization device. Furthermore, this invention fully utilizes elements such as magnesium and calcium contained in the membrane effluent, eliminating the need for the addition and consumption of additional chemical agents, thereby significantly conserving resources and reducing costs. Furthermore, this invention utilizes membrane separation technology to recycle products in three forms: gas, liquid, and solid. Phosphorus removal rates exceeding 80% are achieved, effectively converting sludge into energy and resources. This method offers excellent economic benefits, reliable operation, and is suitable for widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0026] Figure 1 This is a schematic structural diagram of the integrated membrane sludge treatment equipment for sludge resource conversion and energy conversion according to the present invention;

[0027] Among them, 1. Main reaction zone; 11. Mud inlet; 12. First biogas outlet; 13. Agitator; 14. First circulation pipeline; 15. Second circulation pipeline; 16. Sludge pump; 2. Dynamic membrane zone; 21. Second biogas outlet; 22. Membrane water outlet; 23. Mud outlet; 24. Dynamic membrane assembly; 3. Crystallization reaction zone; 31. Anode plate; 32. Cathode membrane; 33. Membrane water outlet; 4. Crystal precipitation zone; 5. Power supply; 51. First electrode; 52. Second electrode.

[0028] Figure 2The present invention is a flow chart of the sludge treatment method for converting sludge into resources and energy. DETAILED DESCRIPTION

[0029] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below with reference to embodiments.

[0030] Combine Figure 1 As shown, the present invention provides a comprehensive membrane sludge treatment equipment for sludge resource and energy conversion, including an anaerobic dynamic membrane bioreactor and an electrochemical membrane filtration phosphorus in situ crystallization device. The anaerobic dynamic membrane bioreactor adopts a split structure, which includes a main reaction zone 1 and a dynamic membrane zone 2 connected by a sludge circulation pipeline; a sludge inlet 11 is provided on the side of the main reaction zone 1, a first biogas outlet 12 is provided on the top, and an agitator 13 is provided inside; a second biogas outlet 21 and a membrane water outlet 22 are provided on the top of the dynamic membrane zone 2, a sludge discharge port 23 is provided at the bottom, and a dynamic membrane assembly 24 is integrated inside; the dynamic membrane assembly 24 includes a plurality of flat membranes arranged at equal intervals, and the flat membrane is provided with an outlet connected to the membrane outlet 22; wherein, the flat membrane serves as the core structure of the dynamic membrane assembly 24, and realizes solid-liquid separation of sludge through membrane separation technology. The flat membrane has a membrane skeleton and a membrane sheet arranged on the surface of the membrane skeleton. The membrane skeleton is an internal hollow frame with a PVC grid inside; the diaphragm is sealed on the membrane skeleton along the four sides, and it uses a large-pore cheap substrate as the supporting material, such as stainless steel mesh, nylon mesh or polyester mesh; a biogas circulation pipeline connected to the biogas is provided at the bottom of the dynamic membrane assembly 24. The electrochemical membrane filtration phosphorus in-situ crystallization device is connected to the membrane outlet 22 of the dynamic membrane zone 2. The electrochemical membrane filtration phosphorus in-situ crystallization device includes a crystallization reaction zone 3 and a crystal precipitation zone 4 arranged above and below. The crystallization reaction zone 3 is provided with an electrochemical membrane assembly connected to a power source 5. The electrochemical membrane assembly includes multiple anode plates 31 and multiple cathode membranes 32 arranged at equal intervals, with a cathode membrane 32 disposed between two adjacent anode plates 31. Each cathode membrane 32 is provided with a cathode membrane outlet. A membrane outlet 33 connected to the cathode membrane outlet is provided above the crystallization reaction zone 3. The crystal precipitation zone 4 has a conical structure and a discharge port at the bottom. The present invention combines an anaerobic dynamic membrane bioreactor with an electrochemical membrane filtration phosphorus in-situ crystallization device, utilizing membrane separation technology to treat and reuse sludge and sludge liquid, collect biogas generated by digestion, and recover phosphorus resources and reuse carbon sources from the membrane effluent.

[0031] Combine Figure 1As shown, in the anaerobic dynamic membrane bioreactor, the volume ratio of the dynamic membrane zone 2 to the main reaction zone 1 is 1:6~1:9; the sludge circulation pipeline includes a first circulation pipeline 14 and a second circulation pipeline 15 connecting the main reaction zone 1 and the dynamic membrane zone 2 respectively, and the second circulation pipeline 15 is provided with a sludge pump 16. The digested sludge in the main reaction zone 1 enters the dynamic membrane zone 2 through the first circulation pipeline 14, and the concentrated sludge after concentration and separation in the dynamic membrane zone 2 is returned to the main reaction zone 1 under the action of the sludge pump 16 for re-digestion; the present invention utilizes the dynamic membrane solid-liquid separation effect to decouple HRT and SRT (HRT=10~20 days, SRT=30~50 days), intercept the solid phase and increase the concentration of functional microorganisms in the reaction system, thereby enhancing the system's organic matter digestion (digestion rate 45%~55%) and biogas recovery (methane yield 0.6~0.8 L / g VS) performance; the effluent of the anaerobic dynamic membrane is rich in nitrogen and phosphorus elements (ammonia nitrogen 200~400 mg / L, phosphate 50~100 mg / L), enters the downstream electrochemical membrane filtration phosphorus recovery device for further recycling.

[0032] Combine Figure 1 As shown, in the electrochemical membrane assembly of the crystallization reaction zone 3, a porous conductive material is used as the cathode membrane 32 (such as a titanium mesh membrane), and a corrosion-resistant conductive material is used as the anode plate 31 (such as a tin-antimony-titanium plate). The distance between adjacent cathode membranes 32 and anode plates 31 is 1-3 cm. Membrane filtration technology is used to enhance material mass transfer and achieve in-situ crystallization and precipitation of resource minerals such as struvite. The membrane flux of the electrochemical membrane filtration phosphorus in-situ crystallization device is controlled to 9-15 L / (m 2 h), the power supply is a DC power supply, and its current density is controlled to be 2-16A / m 2 , preferably 6~10 A / m 2 The phosphorus removal rate is >80%. The electrochemical reduction of organic matter in the membrane effluent increases its biodegradability, allowing it to serve as a supplemental carbon source in the anoxic section of wastewater treatment. The crystal precipitation zone 4 has an inclination angle of 50-70° to facilitate the collection of precipitates that fall from the surface of the cathode membrane 32. The liquid level threshold for the electrochemical membrane filtration phosphorus in-situ crystallization device is between 26 and 30 cm.

[0033] Combine Figure 1 As shown, the anode plate 31 of the electrochemical membrane assembly of the crystallization reaction zone 3 is connected to the first electrode of the power supply 5, and the cathode membrane 32 is connected to the second electrode of the power supply 5. The power supply 5 uses a constant current power supply with a current density of 2-16A / m 2 , preferably 6~10 A / m 2During electrochemical crystallization, the first electrode 51 of the power supply 5 is the positive electrode and the second electrode 52 is the negative electrode. Under electrolysis conditions, a large amount of hydroxide ions are generated on the surface of the cathode membrane 32, thereby increasing the pH value of the surface of the cathode membrane 32 and its vicinity. The phosphate ions in the membrane effluent discharged from the dynamic membrane zone 2 can undergo crystallization reactions with the calcium ions and magnesium ions in the membrane effluent under the high pH environment formed, thereby generating struvite and / or calcium phosphate crystals on the surface of the cathode membrane 32 and its vicinity. Part of the resulting crystalline precipitate enters the crystal precipitation zone 4 under the action of gravity for recovery, thereby realizing the resource utilization of phosphorus, calcium, magnesium, etc. in the sludge liquid.

[0034] Combine Figure 1 As shown, the positive and negative polarities of the first electrode 51 and the second electrode 52 of the controllable power supply 5 can be reversed for 1 to 5 minutes every six to eight hours. Preferably, the positive and negative polarities of the first electrode 51 and the second electrode 52 of the controllable power supply 5 can be reversed for three minutes every six hours. During this polarity reversal, the membrane outlet water of the dynamic membrane zone 2 is controlled to stop being fed into the crystallization reaction zone 3 (for example, the water inlet pump of the crystallization reaction zone 3 is controlled), and the polarity of the first electrode 51 is controlled to be reversed from positive to negative, and the polarity of the second electrode 52 is reversed from negative to positive, so that the polarity of the anode plate 31 is reversed from positive to negative, and the polarity of the cathode membrane 32 is reversed from negative to positive, thereby generating hydrogen ions in and near the cathode membrane 32. The generated hydrogen ions can dissolve the crystalline precipitates attached to the surface of the cathode membrane 32, reducing the adhesion of the crystalline precipitates to the surface of the cathode membrane 32, so that the crystalline precipitates attached to the cathode membrane 32 fall off, and the detached struvite and / or phosphorus crystalline precipitates such as calcium phosphate enter the crystal precipitation zone 4 for recovery, thereby realizing automatic in-situ cleaning of the cathode membrane 32 and automatic collection of the crystalline precipitates. After the polarity reversal is completed, the membrane outlet water of the dynamic membrane zone 2 is controlled to continue to be sent to the crystallization reaction zone 3, and the polarity of the first electrode 51 of the power supply 5 is controlled to be positive and the polarity of the second electrode 52 is controlled to be negative to continue the electrochemical crystallization as described above, thereby continuing to produce crystal precipitation on the cathode membrane 32 and its vicinity.

[0035] like Figure 1 As shown, the material of the cathode membrane 32 can be selected from porous conductive materials such as titanium mesh and stainless steel mesh. More crystallization sites can be provided by increasing the actual surface area of the cathode membrane 32 configuration. For example, the cathode membrane 32 can adopt a titanium mesh with a mesh size of 100 to 400 to improve the phosphorus removal rate as the mesh size of the titanium mesh increases. Preferably, a 300-mesh titanium mesh can be used to greatly improve the phosphorus removal rate and control manufacturing costs. The material of the anode plate 31 can be selected from corrosion-resistant conductive materials such as platinum electrode, platinum-titanium electrode, tin-antimony electrode, etc. The above-mentioned integrated membrane sludge treatment equipment can be applied to sludge resource and energy utilization.

[0036] Figure 2A sludge treatment method for converting sludge into resources and energy is presented, which can couple anaerobic dynamic membrane biological reaction with electrochemical membrane filtration and phosphorus in situ crystallization.

[0037] Combine Figure 1 and Figure 2 As shown, the method includes step 202: sending the sludge into the main reaction zone for digestion; step 204: sending the digested sludge in the main reaction zone to the dynamic membrane zone for concentration and separation; step 206: returning the concentrated sludge in the dynamic membrane zone to the main reaction zone for re-digestion.

[0038] The method further includes step 208: feeding the membrane outlet water of the dynamic membrane area into the crystallization reaction zone to perform in-situ crystallization of electrochemical membrane phosphorus; step 210: controlling the polarity of the first electrode to be positive and the polarity of the second electrode to be negative to generate crystal precipitation on the cathode membrane and its vicinity, and part of the crystal precipitation enters the crystal precipitation zone under the action of gravity; step 212: controlling the polarity of the first electrode and the second electrode to be reversed for 1 to 5 minutes every six to eight hours, and during the polarity reversal, controlling to stop feeding the membrane outlet water of the dynamic membrane area into the crystallization reaction zone, and controlling to make the first electrode The polarity of the electrode is reversed from positive to negative, and the polarity of the second electrode is reversed from negative to positive, so that the crystal precipitate attached to the cathode membrane falls off and enters the crystal precipitation zone and the cathode membrane is automatically cleaned in situ. After the polarity reversal is completed, the process returns to step 208 to control the membrane outlet water of the dynamic membrane area to continue to be sent to the crystallization reaction zone, control the polarity of the first electrode to be positive and the polarity of the second electrode to be negative, so as to continue the electrochemical crystallization as described in step 210 to continue to produce crystal precipitates on the cathode membrane and its vicinity; step 214: recover the crystal precipitate entering the crystal precipitation zone.

[0039] like Figure 1 and 2 As shown, the method may also include collecting biogas generated by sludge digestion. The method may also include returning the effluent from the electrochemical membrane filtration phosphorus recovery device to the front end as a supplementary carbon source for the anoxic tank in the biochemical treatment process of the sewage plant. Figure 1 and 2 As described in Examples 1 and 2 above, a porous conductive material is used as the cathode membrane, and a corrosion-resistant conductive material is used as the anode plate, wherein the spacing between adjacent cathode membranes and anode plates is 1 to 3 cm. The mass transfer of materials is enhanced by membrane filtration technology to achieve in-situ crystallization and precipitation of resource minerals such as struvite. The method also includes controlling the membrane flux of the electrochemical membrane filtration phosphorus in-situ crystallization device to 9 to 15 L / (m 2 h), control the current density to 2-16A / m 2 , preferably 6~10 A / m 2, and controlling the liquid level of the electrochemical membrane filtration phosphorus in-situ crystallization device to 26-30 cm. Preferably, the method further includes controlling the positive and negative polarity of the first electrode 51 and the second electrode 52 of the power supply 5 to reverse for three minutes every six hours.

[0040] The method achieves a phosphorus removal rate of >80%. The electrochemical reduction of organic matter in the membrane effluent increases its biodegradability, allowing it to serve as a supplemental carbon source in the anoxic section of wastewater treatment. The crystal precipitation zone has an inclination angle of 50-70° to facilitate the collection of precipitates shed from the cathode membrane 32.

[0041] Example 1

[0042] In this embodiment, the comprehensive membrane sludge treatment equipment for sludge resource and energy utilization includes an anaerobic dynamic membrane bioreactor and an electrochemical membrane filtration phosphorus in situ crystallization device. The main reaction zone volume of the anaerobic dynamic membrane bioreactor is 675 L, the dynamic membrane zone volume is 75 L, and the volume ratio of the dynamic membrane zone to the main reaction zone is 1:9; the electrochemical membrane filtration phosphorus in situ crystallization device consists of two parts, the crystallization reaction zone and the crystal precipitation zone. The crystallization reaction zone is provided with an electrochemical membrane assembly connected to a power supply. The electrochemical membrane assembly includes multiple anode plates and multiple cathode membranes arranged at equal intervals. A cathode membrane is arranged between adjacent anode plates. Each cathode membrane is provided with a cathode membrane water outlet. A membrane outlet connected to the cathode membrane water outlet is provided above the crystallization reaction zone; the inclination angle of the crystal precipitation zone is set to 60°.

[0043] The anaerobic dynamic membrane bioreactor achieves solid-liquid separation and sludge concentration by decoupling the hydraulic retention time and solid retention time (HRT=10 days, SRT=30 days) of the dynamic membrane. The sludge concentration in the main reaction zone is 36.5 g / L, and the sludge concentration in the dynamic membrane zone is 43.3 g / L. The VS digestion rate reaches 40.5%, and the biogas yield reaches 0.59 L / g VS. The membrane effluent of the anaerobic dynamic membrane bioreactor contains 274 mg / L of ammonia nitrogen and 56 mg / L of phosphate. After entering the electrochemical membrane filtration phosphorus in situ crystallization device, titanium mesh is used as the cathode membrane of the electrochemical membrane assembly in the crystallization reaction zone, and corrosion-resistant conductive material is used as the anode plate. The distance between adjacent cathode membranes and anode plates is 2 cm. The electrochemical membrane assembly can enhance material mass transfer and realize the in situ crystallization and precipitation of resource minerals such as struvite. The membrane flux of the electrochemical membrane filtration phosphorus in situ crystallization device is 12 L / (m 2 h), the current density is 8 A / m 2The resulting crystals precipitate into the crystal precipitation zone under the action of gravity. Furthermore, by reversing the polarity of the anode plate and cathode membrane for 1 to 5 minutes every six to eight hours—ideally, reversing the polarity of the anode plate and cathode membrane for three minutes every six hours—some struvite and other resource mineral crystals can be shed from the surface of the cathode membrane and recovered in the crystal precipitation zone, achieving in-situ cleaning of the cathode membrane and automated collection of the crystals. The treated sludge achieves a phosphorus removal rate of 85%. The effluent from the subsequent electrochemical membrane filtration phosphorus recovery unit is then returned to the front end as a supplemental carbon source for the anoxic tank in the wastewater plant's biochemical treatment process.

[0044] Example 2

[0045] In this embodiment, the sludge is treated by anaerobic digestion using the comprehensive membrane sludge treatment equipment for sludge resource and energy conversion of the present invention:

[0046] Most of the present embodiment is the same as that of Example 1, except that the HRT of the anaerobic dynamic membrane bioreactor is 10 days, the SRT is 40 days, the sludge concentration in the main reaction zone is 41.6 g / L, the sludge concentration in the dynamic membrane zone is 51.0 g / L, the VS digestion rate is 43.3%, and the biogas yield is 0.69 L / g VS.

[0047] Based on the zero-carbon emission anaerobic digestion process of sludge, the present invention has developed a set of equipment that couples an anaerobic dynamic membrane bioreactor and an electrochemical membrane filtration phosphorus in situ crystallization device. The membrane separation technology is used to recover the products in three forms of gas, liquid and solid, realizing the resource and energy conversion of sludge. It has good economic benefits, reliable operation and can be promoted.

[0048] Combine Figure 1 and 2 As described in Examples 1 and 2, the present invention has the following beneficial effects: 1. This invention combines an anaerobic dynamic membrane bioreactor with an electrochemical membrane filtration phosphorus in-situ crystallization device. In the AnDMBR device, the dynamic membrane solid-liquid separation effect is used to decouple the sludge's HRT (hydraulic retention time) and SRT (solids retention time), trapping the solid phase and increasing the concentration of functional microorganisms in the reaction system, thereby enhancing the system's organic matter degradation and biogas recovery performance. 2. The effluent from the anaerobic dynamic membrane of the present invention is rich in nitrogen and phosphorus elements and enters the downstream electrochemical membrane filtration phosphorus recovery device. The membrane filtration technology enhances material mass transfer, achieving crystallization and precipitation of resource minerals such as struvite. The organic matter components in the membrane effluent are biodegradable through the electrochemical reduction of the cathode membrane, and can be used as a supplementary carbon source in the anoxic section of the sewage treatment. The lower part of the device is a crystal precipitation area, which is convenient for collecting crystals falling off the cathode surface and can realize automatic cleaning of the electrochemical membrane. 3. This invention, based on an anaerobic dynamic membrane bioreactor, couples an electrochemical membrane filtration phosphorus in-situ crystallization device. Furthermore, this invention fully utilizes elements such as magnesium and calcium contained in the membrane effluent, eliminating the need for the addition and consumption of additional chemical agents, thereby conserving resources and reducing costs. Furthermore, this invention utilizes membrane separation technology to recycle products in three forms: gas, liquid, and solid. The phosphorus removal rate can reach over 80%, achieving resource-to-energy conversion of sludge. This method offers good economic benefits, reliable operation, and is suitable for widespread adoption.

[0049] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A comprehensive membrane sludge treatment equipment, characterized in that, It includes an anaerobic dynamic membrane bioreactor and an electrochemical membrane filtration phosphorus in-situ crystallization device; The anaerobic dynamic membrane bioreactor is used for anaerobic digestion and concentration separation of sludge. The anaerobic dynamic membrane bioreactor is a split structure, which includes a main reaction zone and a dynamic membrane zone connected by a sludge circulation pipeline; the side of the main reaction zone is provided with a mud inlet, the top is provided with a first biogas outlet, and an agitator is provided inside; the top of the dynamic membrane zone is provided with a second biogas outlet and a membrane water outlet, the bottom is provided with a mud outlet, and a dynamic membrane assembly is integrated inside; the dynamic membrane assembly includes a plurality of flat membranes arranged at equal distances, the flat membranes are provided with an outlet connected to the membrane water outlet, and the bottom of the dynamic membrane assembly is provided with a biogas circulation pipeline connected to the biogas; The electrochemical membrane filtration phosphorus in situ crystallization device is used to perform in situ crystallization of phosphorus on membrane effluent from the dynamic membrane zone, and the electrochemical membrane filtration phosphorus in situ crystallization device is connected to the membrane outlet of the dynamic membrane zone; the electrochemical membrane filtration phosphorus in situ crystallization device includes a crystallization reaction zone and a crystal precipitation zone arranged above and below; an electrochemical membrane assembly connected to a power supply is provided in the crystallization reaction zone, and the electrochemical membrane assembly includes a plurality of anode plates and a plurality of cathode membranes arranged at equal intervals, a cathode membrane is provided between two adjacent anode plates, and each cathode membrane is provided with a cathode membrane outlet; a membrane outlet connected to the cathode membrane outlet is provided above the crystallization reaction zone; the crystal precipitation zone is a conical structure, and a discharge port is provided at the bottom; the anode plate is connected to a first electrode of a power supply, and the cathode membrane is connected to a second electrode of the power supply.

2. The comprehensive membrane sludge treatment equipment according to claim 1, characterized in that: The cathode membrane is made of porous conductive material, which includes titanium mesh and stainless steel mesh. The anode plate is made of corrosion-resistant conductive material, which includes platinum electrode, platinum-titanium electrode and tin-antimony electrode. The titanium mesh is 100-400 mesh. The liquid level of the electrochemical membrane filtration phosphorus in-situ crystallization device is 26-30 cm. The membrane flux threshold of the electrochemical membrane filtration phosphorus in-situ crystallization device is 9-15 L / (m 2 h), the current density of the power supply is 2-16A / m 2 The distance between adjacent cathode membranes and anode plates is 1~3cm.

3. The comprehensive membrane sludge treatment equipment according to claim 2, characterized in that: The current density is 6-10A / m 2 The titanium mesh is 300 mesh, and the distance between adjacent cathode membranes and anode plates is 2 cm.

4. The integrated membrane sludge treatment equipment according to claim 3, characterized in that: The inclination angle of the crystal precipitation zone is set to 50-70°.

5. The integrated membrane sludge treatment equipment according to claim 1, characterized in that: The volume ratio of the dynamic membrane zone to the main reaction zone is 1:6 to 1:

9.

6. The integrated membrane sludge treatment equipment according to claim 1, characterized in that: The sludge circulation pipeline includes a first circulation pipeline and a second circulation pipeline respectively connecting the main reaction zone and the dynamic membrane zone, and a sludge pump is provided on the second circulation pipeline.

7. A sludge treatment method for the integrated membrane sludge treatment equipment according to any one of claims 1 to 6, characterized in that: include: The sludge is sent to the main reaction zone of the anaerobic dynamic membrane bioreactor for digestion; The digested sludge in the main reaction zone is sent to the dynamic membrane zone for concentration and separation; Returning the concentrated sludge from the dynamic membrane zone to the main reaction zone for re-digestion; sending the membrane effluent of the dynamic membrane zone into the crystallization reaction zone of the electrochemical membrane filtration phosphorus in-situ crystallization device; Controlling the polarity of the first electrode to be positive and the polarity of the second electrode to be negative to generate crystal precipitation on the cathode film and its vicinity, with part of the crystal precipitation entering the crystal precipitation zone under the action of gravity; The polarity of the first electrode and the second electrode is controlled to be reversed for 1 to 5 minutes every six to eight hours. During the polarity reversal, the membrane outlet water of the dynamic membrane area is controlled to stop being fed into the crystallization reaction area. The polarity of the first electrode is controlled to be reversed from positive to negative, and the polarity of the second electrode is controlled to be reversed from negative to positive, so that the crystal precipitate attached to the cathode membrane falls off and enters the crystal precipitation area and the cathode membrane is automatically cleaned in situ. After the polarity reversal is completed, the membrane outlet water of the dynamic membrane area is controlled to continue being fed into the crystallization reaction area. The polarity of the first electrode is controlled to be positive and the polarity of the second electrode is controlled to be negative, so that crystal precipitate continues to be generated on the cathode membrane and in the vicinity thereof. The crystal precipitate entering the crystal precipitation zone is recovered.

8. The sludge treatment method according to claim 7, characterized in that: The method further comprises controlling the membrane flux of the electrochemical membrane filtration phosphorus in-situ crystallization device to be 9-15 L / (m 2 h), controlling the current density of the power supply to be 2-16A / m 2 , and controlling the liquid level of the electrochemical membrane filtration phosphorus in-situ crystallization device to 26~30 cm, and controlling the polarity of the first electrode and the second electrode to reverse for three minutes every six hours.

9. The sludge treatment method according to claim 8, characterized in that: The method further comprises controlling the membrane flux to be 12 L / (m 2 h), controlling the current density to 8 A / m 2 .

10. The sludge treatment method according to claim 7, characterized in that: The method further comprises collecting biogas generated by sludge digestion and returning the effluent of the electrochemical membrane filtration phosphorus in-situ crystallization device to the front end as a supplementary carbon source.

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