Integrated device for coupling anaerobic biological treatment of wastewater with fatty acid recovery

Abstract

The invention relates to a wastewater treatment technology. The invention discloses a wastewater anaerobic biological treatment coupled fatty acid recovery integrated device, which comprises a reaction chamber, a water distributor is arranged at the bottom of the reaction chamber, a gas collection chamber is arranged at the top of the reaction chamber, an anaerobic reaction zone is arranged above the water distributor, the anaerobic reaction zone is filled with anaerobic granular sludge, and the gas collection chamber is arranged above the anaerobic reaction zone. The wastewater is uniformly distributed through the water distributor and enters the anaerobic reaction zone to be treated, and gas generated in the treatment process is collected in the gas collection chamber; a fatty acid recovery area is arranged at the top of the anaerobic reaction area, and an isolation device is mounted between the anaerobic reaction area and the fatty acid recovery area and used for controlling isolation and opening of the anaerobic reaction area and the fatty acid recovery area; the fatty acid recovery area is filled with anion resin and is provided with a regeneration liquid injection device and a fatty acid absorber, the regeneration liquid injection device is used for injecting regeneration liquid, and the fatty acid absorber is used for recovering fatty acid. According to the invention, automatic recovery of fatty acid and full-automatic regeneration of anion resin are realized.

Description

Technical Field

[0001] The present application relates to the field of wastewater treatment technology, in particular to wastewater anaerobic biological treatment technology, and specifically to an integrated device for wastewater anaerobic biological treatment coupled with fatty acid recovery. Background Art

[0002] In the current global context of environmental protection and sustainable development, wastewater treatment and resource recovery have become crucial issues in the environmental protection field. In industrial wastewater treatment, achieving both purification and conversion of organic matter into high-value-added products is a particular challenge facing wastewater treatment projects. Food processing and oil and fat industries contain large quantities of fatty acids in their wastewater. Recovering these fatty acids not only reduces environmental pollution but also recycles resources and reduces carbon emissions.

[0003] Among wastewater treatment technologies, anaerobic biological treatment has been a rapidly developing area in recent years. Under anaerobic conditions, facultative anaerobic and anaerobic microbial communities convert organic matter into methane and carbon dioxide. This technology has been widely used in the treatment of high-concentration organic wastewater, such as brewery wastewater, papermaking wastewater, and food processing wastewater.

[0004] The basic structure of an anaerobic biological treatment unit consists of a corrosion-resistant reaction chamber containing an anaerobic sludge blanket. The reactor consists of a cylindrical reaction chamber with a water inlet pipe and a water distributor installed at the bottom. The anaerobic sludge blanket is placed above the distributor. During operation, wastewater enters the bottom of the reactor through uniform water distribution and flows upward through the anaerobic sludge blanket for biodegradation. Finally, a three-phase separator removes solid waste and collects biogas and liquid. For more detailed information on the principles of anaerobic treatment and the reaction chamber structure, please refer to the technical solution disclosed in Chinese Patent Publication No. CN114394665A.

[0005] Extracting fatty acids during wastewater treatment is particularly well-suited to current trends in environmental protection technology. Chinese Patent Publication No. CN119685439A discloses a method and apparatus for in-situ screening of microbial communities and anaerobic acid production enrichment based on selective metal ion removal. The main drawbacks of these existing wastewater treatment and fatty acid extraction devices are their complex structure, high energy consumption, and large footprint. Summary of the Invention

[0006] The main purpose of this application is to provide an integrated device for anaerobic biological treatment of wastewater coupled with fatty acid recovery, so as to solve the problems of complex structure and high energy consumption of the existing wastewater treatment and fatty acid extraction devices.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of a specific embodiment of the present application, an integrated device for anaerobic biological treatment of wastewater coupled with fatty acid recovery is provided, comprising a reaction chamber, a water distributor at the bottom of the reaction chamber and a gas collecting chamber at the top, an anaerobic reaction zone above the water distributor, the anaerobic reaction zone being filled with anaerobic granular sludge, the wastewater being evenly distributed through the water distributor and entering the anaerobic reaction zone for treatment, and the gas generated during the treatment process being collected in the gas collecting chamber; characterized in that a fatty acid recovery zone is provided on the top of the anaerobic reaction zone, an isolation device is installed between the anaerobic reaction zone and the fatty acid recovery zone, for controlling the isolation and opening of the anaerobic reaction zone and the fatty acid recovery zone; the fatty acid recovery zone is filled with anion resin and is equipped with a regeneration liquid injection device and a fatty acid absorber, the regeneration liquid injection device is used to add regeneration liquid, and the fatty acid absorber is used to recover fatty acids.

[0008] In certain embodiments, the reaction chamber is substantially cylindrical.

[0009] In certain embodiments, the isolation device includes a grid and a silicone rubber telescopic sealing skirt; the silicone rubber telescopic sealing skirt is arranged under the grid, and the conversion between the isolation state and the open state is achieved by inflation and exhaust; after inflation, the silicone rubber sealing skirt is tightly attached to the grid to block the holes of the grid to achieve isolation, and after exhaust, the silicone rubber sealing skirt is separated from the grid, allowing the liquid to pass through the holes of the grid and enter the fatty acid recovery area.

[0010] In some embodiments, the regeneration liquid injection device includes a variable diameter annular distribution pipe and a filling pipe; the variable diameter annular distribution pipe is used to evenly distribute the regeneration liquid, and the filling pipe is connected to the variable diameter annular distribution pipe for inputting the regeneration liquid.

[0011] In some embodiments, the variable diameter annular distribution pipe is a stainless steel pipe, which forms a circular ring. The two ends of the circular ring are connected to the filling pipe. The diameter of the stainless steel pipe is a gradual pipe diameter. The diameter of the pipe at the connection with the filling pipe is smaller and gradually expands towards the two ends.

[0012] In certain embodiments, a drainage device is installed above the fatty acid recovery area to drain the liquid when the liquid level reaches a set position.

[0013] In some embodiments, the drainage device is composed of an inverted U-shaped siphon tube, which uses the siphon effect to drain the liquid.

[0014] In certain embodiments, the gas collection chamber is equipped with a pressure regulating valve for cooperating with an inverted U-shaped siphon to control liquid discharge.

[0015] In certain embodiments, the regeneration solution is a mixture of NaOH and NaCl.

[0016] In certain embodiments, the mixed solution contains 0.5 mol / L NaOH and 1.0 mol / L NaCl.

[0017] According to the technical solution of the present application and the further improved technical solution in certain exemplary embodiments thereof, the present application has the following beneficial effects:

[0018] This system achieves automated fatty acid recovery and fully automatic regeneration of anion exchange resins. Treated wastewater is discharged by gravity, without the need for external energy, achieving both energy conservation and high efficiency. A three-dimensional water distributor ensures more uniform wastewater distribution, improving the efficiency of the anaerobic acidification reaction. The use of a variable-diameter annular distribution pipe ensures even distribution of the regenerated liquid, making it more suitable for adsorption by the anion exchange resin. From bottom to top, the entire device comprises an inlet area, an anaerobic reaction area, a fatty acid recovery area, an outlet area, and a gas collection area. The device boasts a compact structure and a small footprint.

[0019] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present application will be partially given in the following description, partially become apparent from the following description, or be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings that constitute part of this application are used to provide a further understanding of this application. The specific implementation methods, illustrative examples, and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0021] Figure 1 is a plan view of Example 1 of the present application;

[0022] Figure 2 yes Figure 1 A top view of

[0023] Figure 3 is a structural diagram of Example 1;

[0024] Figure 4a Schematic diagram of the grid plate and telescopic sealing skirt structure of Example 1;

[0025] Figure 4b yes Figure 4a AA cross-sectional view;

[0026] Figure 5a 1 is a top view of the regeneration liquid injection device of Example 1;

[0027] Figure 5b Schematic diagram of the structure of the regeneration liquid injection device of Example 1;

[0028] Figure 5c yes Figure 5b BB cross-sectional view;

[0029] Figure 6 1 is a schematic diagram of the recovery pipe structure of Example 1;

[0030] Figure 7a is a cross-sectional view of the isolation device of Example 2 in an isolated state;

[0031] Figure 7b This is a cross-sectional view of the isolator device of Example 2 in the open state.

[0032] In the figure: I is the water inlet area; II is the anaerobic reaction area; III is the fatty acid recovery area; IV is the water outlet area; V is the gas collecting chamber; 1 is the water inlet pipe; 2 is the three-dimensional water distributor; 3 is the water outlet pipe; 4 is the telescopic sealing skirt; 40 is the bracket; 5 is the grid plate; 6 is the recovery pipe; 7 is the anion resin; 8 is the filling pipe; 80 is the variable diameter annular distribution pipe; 9 is the inverted U-shaped siphon; 10 is the gas outlet pipe; 11 is the gas collection pipe; 12 is the gas collecting chamber; 13 is the pressure reducing valve; 50 is the position through hole; 51 and 52 are stainless steel plates; 100 is the reaction chamber. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the specific implementations, exemplary embodiments, and features thereof in this application may be combined with each other. This application will now be described in detail with reference to the accompanying drawings and in conjunction with the following content.

[0034] In order to enable those skilled in the art to better understand the solution of this application, the following will be combined with the drawings in the specific implementation methods and exemplary embodiments of this application to clearly and completely describe the technical solutions in the specific implementation methods and exemplary embodiments of this application. Obviously, the exemplary embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the specific implementation methods and exemplary embodiments in this application, all other implementation methods and embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of this application.

[0035] The technical solution of the present application adds a fatty acid recovery zone to the reaction chamber of the wastewater anaerobic biological device, fully utilizes the fatty acids produced by hydrolysis and acidification reactions during the anaerobic treatment process, and collects and recovers fatty acids through ion exchange adsorption of fatty acids.

[0036] Example 1

[0037] The technical solution of the present application is further elaborated and illustrated below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1-3As shown, the integrated device for anaerobic wastewater biological treatment coupled with fatty acid recovery of the present application includes a reaction chamber 100. The overall configuration of the reaction chamber 100 is cylindrical, with a height H = 3300 mm and a bottom cylindrical diameter R = 2000 mm. The reaction chamber includes, from bottom to top, an inlet area I, an anaerobic reaction area II, a fatty acid recovery area III, an outlet area IV, and a gas collection area V. Except for the inlet area, the height ratio of each functional area is: II:III:IV:V = 4:4:2:1, and the volume ratio is: II:III:IV:V = 2:2:2:1.

[0039] The specific structure is as follows:

[0040] The water inlet area I is located at the bottom of the reaction chamber 100 and is provided with a water inlet pipe 1 with a diameter of 100 mm. The water inlet pipe 1 is connected to the water distributor 2. The water distributor 2 adopts a three-dimensional water distributor. The installation position is 200 mm away from the bottom of the anaerobic reaction area and is arranged in a radial branch to ensure uniform distribution of wastewater.

[0041] The anaerobic reaction zone II is located above the water distributor and is filled with anaerobic granular sludge. An isolation device is installed on the top of the anaerobic reaction zone II to isolate the anaerobic reaction zone and the fatty acid recovery zone during fatty acid recovery. The isolation device in this example includes a grid plate 5 and a silicone rubber telescopic sealing skirt 4. The aperture of the grid plate 5 is 10 mm, which can isolate the anaerobic sludge. A silicone rubber telescopic sealing skirt 4 is installed under the grid plate 5, the outer diameter of which is 20 mm larger than that of the grid plate 5 (total outer diameter 2000 mm), and is connected to the pneumatic drive system (including piston, cylinder, solenoid valve, etc.). The grid plate 5 and the silicone rubber telescopic sealing skirt 4 together constitute the isolation device of this example, which controls inflation and exhaust through air pressure to achieve conversion between the isolation state and the open state. After inflation, the upper part of the silicone rubber sealing skirt 4 is tightly attached to the grid plate 5 to block the holes in the grid plate, and the lower part extends downward to form an air column to achieve isolation. After exhaust, the upper part of the silicone rubber sealing skirt 4 separates from the grid plate 5 and returns to the surface of the bracket 40. The lower air column shrinks back to its original shape and covers the surface of the bracket 40, allowing liquid to pass through the holes in the grid plate and the silicone rubber sealing skirt into the fatty acid recovery area. During the resin regeneration stage, a physical separation is formed between the anaerobic reaction area II and the fatty acid recovery area III. Figure 4a and Figure 4b shown.

[0042] Fatty Acid Recovery Zone III: Structurally located at the top of the anaerobic reaction zone, it is filled with an anion resin 7 (model D201) with a height of h = 1000 mm. A regeneration liquid injection device, comprising a filling pipe 8 and a variable-diameter annular distribution pipe 80, is located 150 mm from the top of Fatty Acid Recovery Zone III. This device is used to inject regeneration liquid. The diameter of the variable-diameter annular distribution pipe 80 is 20 mm at the connection with the filling pipe 8, gradually expanding to 30 mm in the middle. 3 mm-diameter inclined holes (pointing downward at 15°) are provided on the pipe surface at 150 mm intervals. A flow control valve and a pressure gauge are installed at the inlet of the filling pipe 8.

[0043] In this example, the regeneration liquid is a mixed solution containing 0.5 mol / L NaOH and 1.0 mol / L NaCl, which can effectively achieve resin regeneration and promote fatty acid desorption.

[0044] The structure of the regeneration liquid injection device in this example is as follows Figures 5a-5c As shown, the variable diameter annular distribution pipe 80 is made of a stainless steel pipe, which forms a circular ring. The two ends of the circular ring diameter are connected to the filling pipe. The diameter of the stainless steel pipe is a gradual diameter. The diameter of the pipe where it is connected to the filling pipe is smaller and gradually expands towards the two ends. The aperture on the variable diameter annular distribution pipe 80 is also 3mm from the smallest diameter to 1 / 3 at both ends, 6mm from 1 / 3 to 2 / 3 on both sides, and 9mm from 2 / 3 to the largest diameter. This variable diameter annular distribution pipe in this example uses diameter changes in conjunction with aperture changes to achieve uniform injection of regeneration liquid. It has a simple structure, does not require an additional stirring device, is low in cost, is conducive to the uniformity of regeneration liquid injection, and makes the injected regeneration liquid as evenly distributed as possible in the fatty acid recovery zone III, which is very suitable for this integrated reaction chamber structure.

[0045] Outlet zone IV: Located above fatty acid recovery zone III, four stainless steel inverted U-shaped siphon pipes 9 are arranged, symmetrically distributed at 90° intervals. The water inlet end of the siphon pipe is 50 mm away from the variable diameter distribution pipe, and the outlet water flows into the outlet pipe 3 with a diameter of 80 mm.

[0046] Gas collecting chamber V: Located at the top of the reaction chamber, it is the location of the gas collecting chamber 12. The gas outlet pipe 10, gas collection pipe 11 and pressure reducing valve 13 are installed here. The opening and closing pressures of the pressure reducing valve 13 are set to 105-110kPa and 95-100kPa respectively.

[0047] The wastewater treatment process of this device is described as follows:

[0048] Wastewater enters the three-dimensional water distributor through the water inlet pipe and rises evenly to the anaerobic reaction zone II. Under the action of anaerobic microorganisms, it comes into contact with granular sludge to undergo anaerobic hydrolysis and acidification reactions, and organic matter is converted into volatile fatty acids. The wastewater continues to flow upward, passes through the grating to filter the sludge, and enters the fatty acid recovery zone III. The anion resin 7 adsorbs fatty acids through ion exchange, and the treated wastewater level rises to the top of the siphon tube 9 (preset height), triggering drainage. When the liquid level touches the inverted U-shaped siphon tube 9, the siphon effect is activated, and the wastewater is quickly discharged into the outlet pipe 3 through four siphon tubes. The pressure reducing valve in the gas collection area controls the pressure in real time. When the pressure exceeds 110kPa, the exhaust is released to reduce the pressure, and when it is below 95kPa, it is closed to maintain the system pressure balance. In this example, the drainage device composed of the inverted U-shaped siphon tube cooperates with the pressure control system of the gas collection chamber to drain water by the siphon effect, which can reduce the structure of the drainage device and help save energy.

[0049] During regeneration, the water inlet pipe 1 is closed, the air pressure drive system is started, and the edges of the telescopic sealing skirt 4 are extended downward until they are tightly fitted with the grid plate 5, isolating the anaerobic reaction zone II from the recovery zone III. Then, the inlet valve of the filling pipe 8 is opened, and the regeneration liquid containing 0.5 mol / L NaOH and 1.0 mol / L NaCl is injected at a flow rate of 1 m / s and a pressure of 101 kPa. The liquid is evenly distributed through the variable diameter annular distribution pipe 80 to desorb the fatty acids adsorbed by the resin. The desorbed liquid passes through the fatty acid absorber above the grid plate 5 - the cross-shaped recovery pipe 6 (such as Figure 6 The recovered fatty acid solution enters the subsequent purification unit (as shown). After regeneration is complete, the sealing skirt retracts and resets. Gases such as methane (CH4) and carbon dioxide (CO2) produced by the anaerobic reaction are temporarily stored in the gas collection chamber and then transported to the gas treatment system via the outlet pipe. The pressure reducing valve is linked to the gas collection pipe to prevent the risk of overpressure and ensure safe operation of the device.

[0050] The technical solution of this application sets up a fatty acid recovery zone in the reaction chamber of the anaerobic biological treatment device to recover fatty acids during the wastewater treatment process. It is an integrated device for wastewater treatment and fatty acid recovery. Due to the structural limitations of the integrated device and considering compatibility with the anaerobic biological treatment process, the design of the isolation device requires a simple structure and easy operation. Similarly, the regeneration liquid injection device also needs to reduce complexity and improve liquid injection uniformity. The isolation device and regeneration liquid injection device provided below can be used as an alternative solution:

[0051] Example 2

[0052] The structure of the device in this example is the same as that of Example 1, except that the structures of the isolation device and the regeneration liquid filling device are different, which are described below respectively:

[0053] The isolation device in this example is composed of two identical circular stainless steel plates 51 and 52. The two stainless steel plates are concentrically arranged and each has a 10mm through hole 50. The stainless steel plate 52 is fixed and the stainless steel plate 51 can be rotated to a certain angle. When regeneration is in progress, the water inlet pipe 1 is closed and the stainless steel plate 51 is rotated so that the through holes 50 of the two stainless steel plates are staggered to achieve isolation between the anaerobic reaction zone and the fatty acid recovery zone. Figure 7a After regeneration is completed, the anaerobic reaction zone and the fatty acid recovery zone can be reopened (connected) by rotating the stainless steel plate 51 so that the through holes 50 of the two stainless steel plates overlap, as shown. Figure 7b shown.

[0054] The regeneration liquid filling device in this example can be composed of a number of nozzles similar to shower heads. These nozzles are connected to the regeneration liquid and are evenly distributed on the fatty acid recovery area, which can also achieve uniform filling of the regeneration liquid.

[0055] The embodiments described above are only preferred embodiments of the present application and are not intended to limit the technical solutions of the present application. For example, the dimensions (H, R) of the reaction chamber 100, the anion resin filling height h, and other pipe diameters can be selected according to the specific wastewater treatment capacity and are not limited to the dimensions given in the above embodiments. Ordinary technicians in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical solution obtained by equivalent replacement or equivalent conversion falls within the scope of protection of the present application.

Claims

1. An integrated device for anaerobic biological treatment of wastewater coupled with fatty acid recovery, comprising a reaction chamber, a water distributor at the bottom of the reaction chamber, and a gas collecting chamber at the top. Above the water distributor is an anaerobic reaction zone, which is filled with anaerobic granular sludge. Sewage is evenly distributed through the water distributor and enters the anaerobic reaction zone for treatment. Gas generated during the treatment process is collected in the gas collecting chamber; characterized in that: A fatty acid recovery zone is provided on the top of the anaerobic reaction zone, and an isolation device is installed between the anaerobic reaction zone and the fatty acid recovery zone to control the isolation and opening of the anaerobic reaction zone and the fatty acid recovery zone; the fatty acid recovery zone is filled with anion resin and is equipped with a regeneration liquid injection device and a fatty acid absorber, the regeneration liquid injection device is used to add regeneration liquid, and the fatty acid absorber is used to recover fatty acids.

2. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 1, characterized in that: The reaction chamber is substantially cylindrical.

3. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 1, characterized in that: The isolation device includes a grid plate and a silicone rubber telescopic sealing skirt; the silicone rubber telescopic sealing skirt is arranged under the grid plate and realizes the conversion between the isolation state and the open state through inflation and exhaust.

4. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 1, characterized in that: The regeneration liquid injection device includes a variable diameter annular distribution pipe and a filling pipe; the variable diameter annular distribution pipe is used to evenly distribute the regeneration liquid, and the filling pipe is connected to the variable diameter annular distribution pipe for inputting the regeneration liquid.

5. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 4, characterized in that: The variable diameter annular distribution pipe is a stainless steel pipe, which forms a circular ring. The two ends of the circular ring are connected to the filling pipe. The diameter of the stainless steel pipe is a gradual pipe diameter. The diameter of the pipe at the connection with the filling pipe is smaller and gradually expands towards the two ends.

6. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 1, characterized in that: A drainage device is installed above the fatty acid recovery area to drain the liquid when the liquid level reaches a set position.

7. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 6, characterized in that: The drainage device is composed of an inverted U-shaped siphon pipe and uses the siphon effect to drain liquid.

8. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 7, characterized in that: The gas collecting chamber is equipped with a pressure regulating valve for cooperating with an inverted U-shaped siphon to control liquid discharge.

9. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 1, characterized in that: The regeneration liquid is a mixture of NaOH and NaCl.

10. The integrated device for anaerobic wastewater treatment coupled with fatty acid recovery according to claim 9, characterized in that: The mixed solution contains 0.5 mol / L NaOH and 1.0 mol / L NaCl.

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