Anaerobic reactor with magnetic field reinforcement and wastewater resource treatment method

Abstract

The present application relates to wastewater resource treatment technical field, especially to a kind of magnetic field reinforced anaerobic reactor and wastewater resource treatment method.The magnetic field reinforced anaerobic reactor provided by the present application, including anaerobic reactor body and multiple magnetic blocks fixed on the outer surface of the anaerobic reactor body, wherein the multiple magnetic blocks are divided into multiple rows and circled on the outer surface of the anaerobic reactor body, and the magnetic blocks in each row are arranged in the order of left, upper, right and down according to the direction of magnetic field.The magnetic field reinforced anaerobic reactor of the present application can convert the movement of microorganisms in the reactor relying on water flow, bubble or itself rising or falling into cutting magnetic induction line movement by using magnetic field, convert kinetic energy into potential energy, enhance the electron transfer between acetogenic bacteria and methanogens, improve the utilization of organic matter in wastewater by acid-producing bacteria and the process of methanogens utilizing electron to reduce carbon dioxide to produce methane, and realize the improvement of energy utilization and methanogenesis efficiency in anaerobic reactor.

Description

Technical Field

[0001] This invention relates to the field of wastewater resource utilization technology, and in particular to a magnetic field-enhanced anaerobic reactor and a wastewater resource utilization method. Background Technology

[0002] Anaerobic fermentation is an important waste resource utilization technology that can produce clean energy sources such as methane and hydrogen while treating wastewater and livestock manure. However, conventional anaerobic reactors face problems such as low efficiency, unstable operation, and inability to handle high-load organic wastewater. Anaerobic fermentation is mainly achieved through electron transfer between symbiotic microorganisms formed by acid-producing bacteria and methanogens, which is considered key to overcoming these problems. Current research focuses on electron transfer to improve the efficiency of anaerobic fermentation, aiming to establish and enhance direct interspecies electron transfer (DIET) between symbiotic microorganisms in the reactor.

[0003] Most existing research focuses on establishing and enhancing electron transfer between microorganisms by adding carbon-based conductive materials (such as granular activated carbon, biochar, carbon nanotubes, and graphene) and iron-based conductive materials (such as magnetite, zero-valent iron, and stainless steel) to the reactor, applying constant or varying voltage inside the reactor, or applying a moving magnetic field outside the reactor. For example, Chinese patent CN117125807A discloses a wastewater treatment system and method for achieving nitrification based on a microbial electrolysis cell; Chinese patent CN105236565B discloses a method for improving COD removal efficiency in anaerobic wastewater treatment by enhancing iron powder with a magnetic field; and Chinese patent CN117247146A discloses a method for promoting anaerobic digestion of urban sludge using magnetic field-driven magnetic biochar. However, these methods are complex and require additional energy input or high-cost magnetic field generating devices, placing high demands on the application scenarios and limiting their applicability. Summary of the Invention

[0004] In view of this, the present invention provides a magnetic field-enhanced anaerobic reactor and a wastewater resource treatment method. The anaerobic reactor provided by the present invention has a simple structure, is easy to build, does not require additional energy input, and is applicable to most anaerobic reactors, and can effectively treat high-load organic wastewater.

[0005] The present invention provides a magnetic field-enhanced anaerobic reactor, comprising an anaerobic reactor body and a plurality of magnetic blocks fixed on the outer surface of the anaerobic reactor body, wherein the plurality of magnetic blocks are arranged in multiple rows around the outer surface of the anaerobic reactor body, and the magnetic blocks in each row are arranged in a cyclical manner according to the magnetic field direction of left, up, right and down.

[0006] In some embodiments of the present invention, the anaerobic reactor body is an upflow anaerobic sludge bed reactor.

[0007] In some embodiments of the present invention, the magnetic block is an N35 magnetic block.

[0008] In some embodiments of the present invention, the effective volume of the anaerobic reactor body is 1L, the inner diameter is 60mm, and the height is 356mm; the outer surface of the anaerobic reactor body is provided with 8 rows of magnetic blocks at equal intervals, each row containing 36 magnetic blocks, and the volume of each magnetic block is 1cm³. 3 .

[0009] In another aspect, the present invention provides a wastewater resource recovery treatment method, comprising the following steps:

[0010] (1) Inoculate the magnetic field-enhanced anaerobic reactor described in any of the aforementioned technical solutions with anaerobic sludge containing magnetite.

[0011] (2) Wastewater is introduced into the magnetic field-enhanced anaerobic reactor for wastewater treatment to obtain treated wastewater and methane.

[0012] In some embodiments of the present invention, the inoculum amount of the anaerobic granular sludge containing magnetite is 225-275 mL / L.

[0013] In some embodiments of the present invention, the method for preparing the anaerobic granular sludge containing magnetite includes the following steps:

[0014] (1) Sludge from a wastewater treatment plant is mixed with nano-magnetite and synthetic wastewater in a ratio of 115-125mL:6g:275-285mL to obtain a sludge-magnetite mixture; wherein the ethanol concentration in the synthetic wastewater is 4.6-4.8g / L and the carbon-nitrogen ratio is 20-26:1.

[0015] (2) The sludge-magnetite mixture is cultured at 35-37℃. When methane can no longer be produced, ethanol is added to make the ethanol concentration in the system the same as the ethanol concentration in the initial sludge-magnetite mixture. The mixture is cultured until methane can no longer be produced. Then the steps of adding ethanol are repeated and the mixture is cultured until methane can no longer be produced to obtain anaerobic granular sludge containing magnetite.

[0016] In some embodiments of the present invention, the diameter of the nano-magnetite is 30-50 nm. In some embodiments of the present invention, the synthetic wastewater includes the following substances at concentrations: 250 mg / L K₂HPO₄, 250 mg / L KH₂PO₄, 300 mg / L MgCl₂, 25 mg / L CaCl₂, 15 mg / L MnCl₂, 25 mg / L FeCl₃, 16 mg / L NiSO₄, 25 mg / L CoCl₂, 11.5 mg / L ZnCl₂, 10.5 mg / L CuCl₂, and 0.8 g / g COD NaHCO₃.

[0017] In some embodiments of the present invention, the hydraulic retention time of the wastewater is 8-24 hours.

[0018] In some embodiments of the present invention, the temperature of the wastewater treatment is 35-37°C.

[0019] This invention provides a magnetic field-enhanced anaerobic reactor, comprising an anaerobic reactor body and multiple magnetic blocks fixed to the outer surface of the anaerobic reactor body. The magnetic blocks are arranged in multiple rows around the outer surface of the anaerobic reactor body, with each row of magnetic blocks arranged cyclically in the order of left, top, right, and bottom magnetic field direction. The magnetic blocks of this invention are designed to concentrate and enhance a relatively uniform magnetic field on one side in the order of top, left, bottom, and right. Combined with the anaerobic reactor, the magnetic field transforms the movement of microorganisms in the reactor—whether relying on water flow, bubbles, or their own upward or downward movement—into movement that cuts magnetic field lines. This converts kinetic energy into potential energy that the microorganisms can utilize, enhancing electron transfer between acetic acid-producing bacteria and methanogenic bacteria. This improves the utilization rate of organic matter in wastewater by acetic acid-producing bacteria and the methanogenic process of reducing carbon dioxide to produce methanogens using electrons, thereby improving energy utilization and methanogenic efficiency in the anaerobic reactor.

[0020] Furthermore, when using the magnetic field-enhanced anaerobic reactor provided by this invention to treat wastewater, under high organic loads or low hydraulic retention times, the increased bubble generation rate or water flow rate significantly enhances the movement speed of microorganisms cutting magnetic field lines, thereby improving energy conversion efficiency. Therefore, this method is suitable for the rapid treatment of wastewater with high organic loads. Since the microbial aggregates convert kinetic energy into electrical potential energy and are consumed when cutting magnetic field lines in the reactor combined with a magnetic field, using the anaerobic reactor of this invention to treat wastewater also prevents microorganisms from being washed out of the reactor, facilitating the recovery of sludge microbial aggregates. In addition, when using the anaerobic reactor of this invention to treat wastewater, the previously neglected portion of energy (i.e., the kinetic energy of microorganisms) is fully utilized, providing a feasible technical solution for improving the resource utilization efficiency of anaerobic reactor wastewater. Attached Figure Description

[0021] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which:

[0022] Figure 1 This is a schematic diagram of the arrangement in one embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of a magnetic field-enhanced anaerobic reactor according to one embodiment of the present invention.

[0024] Figure 3 for Figure 2 The diagram shows the distribution characteristics of the magnetic field direction in a magnetically enhanced anaerobic reactor.

[0025] Figure 4 This is a magnetic field intensity distribution diagram in the magnetic field-enhanced anaerobic reactor used in the embodiments of the present invention, where a shows the longitudinal magnetic field distribution of the anaerobic reactor, and b shows the transverse magnetic field distribution of the anaerobic reactor. Detailed Implementation

[0026] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments described below are for illustrative purposes only and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the reagents and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the following embodiments, conditions and methods known in the art can be used for processing.

[0027] The present invention provides a magnetic field-enhanced anaerobic reactor, comprising an anaerobic reactor body and a plurality of magnetic blocks fixed on the outer surface of the anaerobic reactor body, wherein the plurality of magnetic blocks are arranged in multiple rows around the outer surface of the anaerobic reactor body, and the magnetic blocks in each row are arranged in a cyclical manner according to the magnetic field direction of left, up, right and down.

[0028] like Figure 1 The diagram shown is a schematic representation of the arrangement of magnetic blocks in one embodiment of the present invention. Figure 2 This is a schematic diagram of a magnetically enhanced anaerobic reactor according to one embodiment of the present invention. Figure 2As shown, when using this anaerobic reactor, 250 mL / L of sludge is inoculated into the effective working space 10 of the reactor. Wastewater enters the reactor through the bottom inlet 9, while water at a constant temperature of 35-37°C enters through the insulation layer inlet 8 and exits through the insulation layer outlet 3, maintaining the insulation layer 5 at an environment of 35-37°C. Under the action of specially arranged magnetic blocks 6, the kinetic energy generated by the movement of microorganisms is converted into electrical potential energy, promoting methanogenesis efficiency. The generated gas is collected through the gas collection port 1, and the treated wastewater flows out of the anaerobic reactor through the outlet 2. The three-phase separator 4 is used to prevent sludge from being flushed out of the reactor. A suitable amount of sludge sample can be taken periodically from the sludge sampling port 7 for testing.

[0029] The distribution characteristics of the magnetic field direction within the reactor were modeled and simulated using Maxwell software. The results are as follows: Figure 3 As shown. By Figure 3 It can be seen that the magnetic field-enhanced anaerobic reactor provided by the present invention is filled with a relatively uniform transverse magnetic field.

[0030] The present invention does not impose any particular limitation on the method of fixing the magnetic blocks, as long as it can be fixed to the outer surface of the anaerobic reactor body. In an embodiment of the present invention, the magnetic blocks are placed in a rubber tube according to the aforementioned arrangement to obtain magnetic strips that can surround the anaerobic reactor body, and then multiple magnetic strips are fixed parallel to each other at equal intervals on the outer surface of the anaerobic reactor body.

[0031] This invention does not specifically limit the anaerobic reactor body. In some embodiments of this invention, the anaerobic reactor body is an upflow anaerobic sludge bed reactor.

[0032] In this invention, those skilled in the art can select the size, shape, and magnetic properties of the magnetic block according to the characteristics of the reactor. In some embodiments of this invention, the magnetic block is an N35 magnetic block. In an embodiment of this invention, the magnetic block has a volume of 1 cm³. 3 A cube.

[0033] In some embodiments of the present invention, the effective volume of the anaerobic reactor body is 1L, the inner diameter is 60mm, and the height is 356mm; the outer surface of the anaerobic reactor body is provided with 8 rows of magnetic blocks at equal intervals, each row containing 36 magnetic blocks, and the volume of each magnetic block is 1cm³. 3 The distribution of the magnetic field within the reactor was modeled and simulated using Maxwell software, and the results are as follows: Figure 3 As shown, the simulated reactor has an inner diameter of 60 mm. Figure a illustrates the longitudinal magnetic field distribution of the anaerobic reactor, and figure b illustrates the transverse magnetic field distribution. The black lines represent the reactor's outline. Figure 3It can be seen that the magnetic field strength of the anaerobic reactor in this embodiment varies from 0.001 mT to 11 mT from the center to the inner wall of the reactor. This shows that the anaerobic reactor provided by the present invention concentrates and strengthens the magnetic field on one side of the reactor, which can avoid the use of high-cost magnetic field generating devices.

[0034] The present invention also provides a wastewater resource recovery treatment method, comprising the following steps:

[0035] (1) Inoculate the magnetic field-enhanced anaerobic reactor described in any of the foregoing technical solutions with anaerobic sludge containing magnetite.

[0036] (2) Wastewater is introduced into the magnetic field-enhanced anaerobic reactor for wastewater treatment to obtain treated wastewater and methane.

[0037] In the wastewater resource recovery method provided by this invention, the magnetic field in the anaerobic reactor converts the movement of microorganisms—relying on water flow, bubbles, and their own motion—into movement that cuts magnetic field lines, thus converting kinetic energy into electrical potential energy. This avoids the need for the magnetic field itself to rotate and cut magnetic field lines, preventing additional energy input to the system. The electrical potential energy promotes electron transfer between acetic acid-producing and methanogenic bacteria, improving substrate utilization. Simultaneously, it facilitates the use of electrons in the environment by methanogenic bacteria to combine with carbon dioxide and produce additional methane, achieving a dual improvement in wastewater treatment and methanogenesis efficiency. Furthermore, since the microbial aggregates convert kinetic energy into electrical potential energy and are consumed when moving through the magnetic field in the reactor, the method provided by this invention also prevents microorganisms from being flushed out of the reactor, facilitating the recovery of sludge microbial aggregates.

[0038] In some embodiments of the present invention, the inoculum amount of the anaerobic granular sludge containing magnetite is 225-275 mL / L, preferably 250 mL / L; wherein the unit represents the volume of sludge inoculated per unit reactor.

[0039] In some embodiments of the present invention, the method for preparing the anaerobic granular sludge containing magnetite includes the following steps:

[0040] (1) Sludge from a wastewater treatment plant is mixed with nano-magnetite and synthetic wastewater in a ratio of 115-125mL:6g:275-285mL to obtain a sludge-magnetite mixture; wherein the ethanol concentration in the synthetic wastewater is 4.6-4.8g / L and the carbon-nitrogen ratio is 20-26:1.

[0041] (2) The sludge-magnetite mixture is cultured at 35-37℃. When methane can no longer be produced, ethanol is added to make the ethanol concentration in the system the same as the ethanol concentration in the initial sludge-magnetite mixture. The mixture is cultured until methane can no longer be produced. Then the steps of adding ethanol are repeated and the mixture is cultured until methane can no longer be produced to obtain anaerobic granular sludge containing magnetite.

[0042] The anaerobic granular sludge containing magnetite provided by this invention is enriched with a large number of electroactive microorganisms, which improves the conductivity of the sludge and allows for more effective utilization of electrical potential energy.

[0043] In an embodiment of the present invention, the sludge from the wastewater treatment plant is sludge from a wastewater treatment plant that treats ethanol and / or citric acid, and the total solids (TS) of the sludge is 8.5%-10% and the volatile solids (VS) are 6.5%-7%.

[0044] In some embodiments of the present invention, the magnetite has a diameter of 30-50 nm.

[0045] In some embodiments of the present invention, the ratio of sludge from the wastewater treatment plant to nano-magnetite and synthetic wastewater is 115-125mL:6g:275-285mL, preferably 120mL:6g:280mL.

[0046] In some embodiments of the present invention, the ethanol concentration in the synthetic wastewater is 4.6-4.8 g / L, preferably 4.79 g / L; the carbon-nitrogen ratio (mass ratio) is 20-26:1, preferably 25:1.

[0047] In some embodiments of the present invention, the synthetic wastewater includes the following substances at concentrations: 250 mg / L K₂HPO₄, 250 mg / L KH₂PO₄, 300 mg / L MgCl₂, 25 mg / L CaCl₂, 15 mg / L MnCl₂, 25 mg / L FeCl₃, 16 mg / L NiSO₄, 25 mg / L CoCl₂, 11.5 mg / L ZnCl₂, 10.5 mg / L CuCl₂, and 0.8 g / g COD NaHCO₃.

[0048] In some embodiments of the present invention, the equipment used for cultivation is purged with nitrogen before adding ethanol to maintain an anaerobic environment.

[0049] In some embodiments of the present invention, the culture is carried out at 35-37°C, preferably at 36°C; the culture is carried out in a constant-temperature water bath shaking pot to ensure a constant temperature during culture. In an embodiment of the present invention, the rotation speed of the constant-temperature water bath shaking pot is 120 rpm.

[0050] In some embodiments of the present invention, after cultivation is completed, anaerobic granular sludge containing magnetite is obtained by pouring out the supernatant.

[0051] This invention does not specifically limit the equipment used in the preparation of the anaerobic granular sludge containing magnetite, as long as it can produce the anaerobic granular sludge containing magnetite required by this application. In an embodiment of this invention, before the second addition of ethanol, after taking out the gas phase sample, the headspace is filled with hydrogen, and the methanogenesis rate and ethanol oxidation rate are observed to determine whether the symbiotic microorganisms in the obtained sludge have formed efficient electron transport channels. If the methanogenesis rate and ethanol oxidation rate increase (i.e., metabolism accelerates), it indicates that efficient electron transport channels have been formed.

[0052] In some embodiments of the present invention, the hydraulic retention time of the wastewater is 8-24 hours, specifically 8 hours, 12 hours, 16 hours, 20 hours, or 24 hours. Those skilled in the art can select an appropriate hydraulic retention time based on the wastewater quality.

[0053] In some embodiments of the present invention, the temperature of the wastewater treatment is 35-37°C, specifically 35°C, 36°C or 37°C.

[0054] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] In the following embodiments, the magnetic field-enhanced anaerobic reactor used is as follows: Figure 2 As shown, the magnetic blocks are arranged as follows Figure 1 As shown, the anaerobic reactor body is an upflow anaerobic sludge bed reactor with an effective volume of 1L, an inner diameter of 60mm, and a height of 356mm. Eight rows of magnetic blocks are evenly spaced (2cm) on the outer surface of the anaerobic reactor body, with 36 magnetic blocks in each row. Each magnetic block has a volume of 1cm³. 3 .

[0056] Sludge cultivation:

[0057] The anaerobic granular sludge containing magnetite used in the following examples was obtained through the following steps:

[0058] The synthesis wastewater was prepared according to the following component concentrations: the ethanol concentration in the synthesis wastewater was 4.79 g / L; the carbon-to-nitrogen ratio (mass ratio) was 25:1; and the other substances contained in the synthesis wastewater were: 250 mg / L K₂HPO₄, 250 mg / L KH₂PO₄, 300 mg / L MgCl₂, 25 mg / L CaCl₂, 15 mg / L MnCl₂, 25 mg / L FeCl₃, 16 mg / L NiSO₄, 25 mg / L CoCl₂, 11.5 mg / L ZnCl₂, 10.5 mg / L CuCl₂, and 0.8 g / g COD NaHCO₃.

[0059] Using a 400mL serum bottle, add 120mL of sludge from a wastewater treatment plant that processes ethanol and citric acid, and 6g of 30-50nm diameter magnetite nanoparticles. Then place the serum bottle in a constant-temperature water shaker (120rpm) and incubate at 36°C. When methane production ceases (referred to as the first batch of incubation), take a gas phase sample. Purge the serum bottle with nitrogen to maintain an anaerobic environment. Add ethanol to make the ethanol concentration in the system the same as the initial sludge-magnetite mixture. Continue incubation until methane production ceases (referred to as the second batch of incubation). Take a gas phase sample, and repeat the above steps of adding ethanol until methane production ceases (referred to as the third batch of incubation). The resulting sludge is used for subsequent wastewater treatment and is referred to as "Example Sludge".

[0060] 1. Sludge methane production efficiency

[0061] Control sludge: Sludge was cultivated using the aforementioned method, the only difference being that no nano-magnetite was added.

[0062] During the cultivation process, the modified Gompertz model was used to simulate the maximum methanogenic potential and maximum methanogenic rate during the cultivation of each batch of sludge. The results are shown in Table 1.

[0063] P = P max ×exp{-exp[R max ×e×(λ-t) / P max +1}

[0064] In the formula, P represents the cumulative methane yield during the reaction (mL / gCOD); P max R represents the maximum production potential of methane gas (mL / g COD); max λ represents the maximum methane gas production rate during the reaction process (mL / gCODh); λ is the lag period of the reaction, h and e are constants, 2.71828; t is the time taken to measure the methane content in each gas bag. Wherein, P... max R max λ was derived from fitting real data of the sludge cultivation process.

[0065] Table 1. Methanogenesis rates of each batch of sludge from the examples and control sludge.

[0066]

[0067] As shown in Table 1, the methanogenesis efficiency of the sludge in the examples was significantly improved after three batches of cultivation. The addition of nano-magnetite further promoted methanogenesis efficiency, which was highest in the third batch. The methanogenesis potential of the sludge in the examples was increased by 10.28% compared with the control sludge, and the maximum methanogenesis rate was increased by 29.34%.

[0068] 2. Verify whether an efficient electron transport channel has been formed.

[0069] The sludge was cultured using the sludge culture method described in the previous embodiment, with the only difference being that in the third batch of culture, after adding ethanol, hydrogen gas (100 mL) was simultaneously injected into the headspace of the serum bottle. The remaining amount of ethanol in the system was monitored periodically during the three batches of culture.

[0070] Control sludge: Control sludge was cultured using this method, the difference being that no nano-magnetite was added. Simultaneously, the residual ethanol level in the system was monitored periodically during the three batches of culture. The monitoring results of the residual ethanol level are shown in Table 2:

[0071] Table 2. Monitoring Results of Remaining Ethanol Amount

[0072]

[0073] Table 2 shows that the ability of microorganisms to metabolize ethanol increases with the number of culture batches. However, in the third batch, when the headspace of the serum bottle was filled with hydrogen, the ethanol metabolism rate of the control sludge without nano-magnetite did not change significantly, while the ethanol metabolism rate of the example sludge with added nano-magnetite further accelerated. The methanogenesis efficiency and ethanol metabolism rate of the example sludge increased with the number of culture batches, and even with the addition of magnetite, the high methanogenesis efficiency and ethanol metabolism rate were still maintained under the additional hydrogen partial pressure, indicating that the symbiotic microorganisms in the example sludge formed a highly efficient electron transport channel.

[0074] Example 1

[0075] This embodiment uses the aforementioned... Figure 2 The magnetic field-enhanced anaerobic reactor shown treats simulated wastewater. The only difference between the simulated wastewater and the synthetic wastewater is the concentration of ethanol. The ethanol concentration in the simulated wastewater is 2.4 g / L (equivalent to a COD concentration of 5 g / L).

[0076] The aforementioned anaerobic granular sludge containing magnetite (inoculation concentration of 250 mL / L) was inoculated into a magnetically enhanced anaerobic reactor, followed by the introduction of synthetic wastewater. The temperature of the magnetically enhanced anaerobic reactor was maintained at 37°C, and the wastewater was treated with a hydraulic retention time of 24 h. Once the magnetically enhanced anaerobic reactor was running stably (i.e., methane production and total organic carbon (TOC) removal rate were stable, after 9 days), the methane content was detected using a gas chromatograph equipped with a TCD detector, and the oxidation-reduction potential (OPR), residual ethanol, and residual acetic acid in the effluent were measured. The hydraulic retention time was then varied, and methane production and average ORP were tested at different hydraulic retention times. The results are shown in Tables 3-6.

[0077] Comparative Example 1

[0078] The aforementioned synthetic wastewater was treated using a method similar to that in Example 1, except that the anaerobic reactor used did not have fixed magnetic blocks on its outer surface; instead, the main body of the magnetically enhanced anaerobic reactor (upflow anaerobic sludge bed reactor) from Example 1 was used as the wastewater treatment device. The methane yield, average redox potential, ethanol loading, and acetic acid loading were tested using the method in Example 1 at different hydraulic retention times, and the results are shown in Tables 3-6.

[0079] Table 3. Methane production of Example 1 and Comparative Example 1 at different hydraulic retention times.

[0080]

[0081] As shown in Table 3, when the hydraulic retention times are 24h, 20h, 16h, 12h and 8h, the amount of methane produced by the wastewater treatment method of Example 1 is increased by 3.32%, 5.7%, 10.68%, 14.14% and 13.78% respectively compared with the wastewater treatment method of Comparative Example 1.

[0082] Table 4 Liquid phase oxidation-reduction potentials of Example 1 and Comparative Example 1 at different hydraulic residence times.

[0083] Hydraulic residence time 24h 20h 16h 12h 8h Example 1 (mv) -293.78±10.41 -319.67±2.73 -331.11±2.93 -319.94±2.72 -322.44±3.26 Comparative Example 1 (mv) -273.17±7.12 -277.33±1.80 -300.07±5.46 -289±3.67 -289.83±3.86

[0084] As shown in Table 4, the oxidation-reduction potential of the wastewater treatment method in Example 1 was significantly lower than that in Comparative Example 1 under different hydraulic retention times, indicating that the wastewater treatment method in Example 1 converted more kinetic energy into electrical potential energy.

[0085] Table 5. Ethanol content in the effluent from Example 1 and Comparative Example 1 at different hydraulic retention times.

[0086]

[0087] Table 6. Acetic acid content in Example 1 and Comparative Example 1 at different hydraulic retention times.

[0088]

[0089] As shown in Tables 5 and 6, the wastewater treated in Example 1 contained lower levels of organic matter (ethanol and acetic acid) under different hydraulic retention times, and remained relatively stable at higher organic loads of 10 g / (L*day) and 15 g / (L*day). This indicates that the example can efficiently remove organic matter from water, especially at high organic loads.

[0090] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A wastewater resource recovery treatment method, comprising the following steps: (1) Inoculate anaerobic granular sludge containing magnetite into a magnetically enhanced anaerobic reactor. (2) Wastewater is introduced into the magnetic field-enhanced anaerobic reactor for wastewater treatment to obtain treated wastewater and methane. The magnetic field-enhanced anaerobic reactor includes an anaerobic reactor body and multiple magnetic blocks fixed on the outer surface of the anaerobic reactor body. The multiple magnetic blocks are divided into multiple rows surrounding the outer surface of the anaerobic reactor body, and the magnetic blocks in each row are arranged in a cyclical manner according to the magnetic field direction as left, up, right, and down. The method for preparing the anaerobic granular sludge containing magnetite includes the following steps: (1) Sludge from a wastewater treatment plant is mixed with nano-magnetite and synthetic wastewater in a ratio of 115-125mL:6g:275-285mL to obtain a sludge-magnetite mixture; wherein the ethanol concentration in the synthetic wastewater is 4.6-4.8g / L and the carbon-nitrogen ratio is 20-26:

1. (2) The sludge-magnetite mixture is cultured at 35-37℃. When methane can no longer be produced, ethanol is added to make the ethanol concentration in the system the same as the ethanol concentration in the initial sludge-magnetite mixture. The mixture is cultured until methane can no longer be produced. Then the steps of adding ethanol are repeated and the mixture is cultured until methane can no longer be produced to obtain anaerobic granular sludge containing magnetite.

2. The wastewater resource utilization treatment method according to claim 1, characterized in that, The anaerobic reactor body is an upflow anaerobic sludge bed reactor.

3. The wastewater resource utilization treatment method according to claim 1, characterized in that, The magnetic block is an N35 magnetic block.

4. The wastewater resource utilization treatment method according to any one of claims 1-3, characterized in that, The effective volume of the anaerobic reactor body is 1L, the inner diameter is 60mm, and the height is 356mm. Eight rows of magnetic blocks are evenly spaced on the outer surface of the anaerobic reactor body, with 36 magnetic blocks in each row. The volume of each magnetic block is 1cm³. 3 .

5. The wastewater resource utilization treatment method according to claim 1, characterized in that, The inoculum amount of the anaerobic granular sludge containing magnetite is 225-275 mL / L.

6. The wastewater resource utilization treatment method according to claim 1, characterized in that, The diameter of the nano-magnetite is 30-50 nm; The synthetic wastewater contains the following substances at concentrations: 250 mg / L K₂HPO₄, 250 mg / L KH₂PO₄, 300 mg / L MgCl₂, 25 mg / L CaCl₂, 15 mg / L MnCl₂, 25 mg / L FeCl₃, 16 mg / L NiSO₄, 25 mg / L CoCl₂, 11.5 mg / L ZnCl₂, 10.5 mg / L CuCl₂, and 0.8 g / g COD NaHCO₃.

7. The wastewater resource utilization treatment method according to claim 1 or 5, characterized in that, The hydraulic retention time of the wastewater is 8-24 hours.

8. The wastewater resource utilization treatment method according to claim 1 or 5, characterized in that, The wastewater treatment temperature is 35-37℃.

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