Integrated energy-saving system for sewage treatment and biogas fermentation

Abstract

The present application relates to a kind of sewage treatment integrated biogas fermentation integrated energy-saving system, including mutually connected biochemical treatment module and anaerobic fermentation module, biochemical treatment module includes sequentially connected water distribution area, anaerobic zone, first anoxic zone, first aerobic zone, second anoxic zone, second aerobic zone and sedimentation effluent zone;Anaerobic fermentation module includes sequentially connected feed tank, fermentation tank and biogas slurry tank, and sedimentation effluent zone is connected feed tank by sludge discharge pipe, sludge generated by biochemical treatment module is used as raw material, and is discharged into anaerobic fermentation module;The fermentation tank is connected biogas slurry tank by liquid discharge pipe, and biogas slurry tank is connected second anoxic zone by carbon addition pipe, and the biogas slurry generated by fermentation tank is stored in biogas slurry tank, and biogas slurry can be discharged into second anoxic zone as carbon source.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and specifically relates to an integrated energy-saving system for wastewater treatment combined with biogas fermentation. Background Technology

[0002] Rural populations in my country are scattered, with three peak drainage periods each day: morning, noon, and evening, and almost no drainage at night and in the early morning. Many rural residents work away from home and return during the Spring Festival or holidays, resulting in significant fluctuations in sewage discharge with seasonal and temporal variations. Some livestock wastewater or wastewater from small food processing workshops intermittently flows into the sewage treatment system, causing fluctuations in influent water quality. Due to infrastructure construction, during rainy periods, rainwater and sewage are not completely separated, leading to a sharp increase in influent water load and a sharp decrease in organic load at sewage treatment plants. Currently, rural sewage treatment plants mainly face the following problems: (1) significant fluctuations in influent sewage quality; (2) low carbon and nitrogen content in influent sewage during most periods, preventing effective denitrification by the system, and the addition of external carbon sources will increase operation and maintenance costs; (3) small amount of residual sludge discharged by the system with high water content, resulting in high costs for effective disposal. Summary of the Invention

[0003] To address the above problems, the present invention provides an integrated energy-saving system for wastewater treatment combined with biogas fermentation, comprising a biochemical treatment module and an anaerobic fermentation module connected to each other. The biochemical treatment module includes an influent distribution zone, an anaerobic zone, a primary anoxic zone, a primary aerobic zone, a secondary anoxic zone, a secondary aerobic zone, and a sedimentation effluent zone connected in sequence.

[0004] The anaerobic fermentation module includes a feed tank, a fermentation tank, and a biogas slurry tank connected in sequence. The sedimentation effluent zone is connected to the feed tank through a sludge discharge pipe, and the sludge produced by the biochemical treatment module is discharged into the anaerobic fermentation module as raw material. The fermentation tank is connected to the biogas slurry tank through a discharge pipe, and the biogas slurry tank is connected to the secondary anoxic zone through a carbon addition pipe. The biogas slurry produced by the fermentation tank is discharged into the biogas slurry tank for temporary storage, and the biogas slurry can be discharged into the secondary anoxic zone as a carbon source.

[0005] Optionally, the biochemical treatment module is a cuboid, comprising a first block, a second block, a third block, a sedimentation effluent area, and an equipment block of equal width along its length.

[0006] The first block includes an anaerobic zone and a primary anoxic zone arranged side by side; the second block includes an influent distribution zone and a primary aerobic zone; the third block includes a secondary anoxic zone and a secondary aerobic zone arranged side by side; the equipment block is equipped with at least one aeration blower to provide oxygen to the primary aerobic zone and the secondary aerobic zone;

[0007] A first partition is provided between the first block and the second block, a second partition is provided between the second block and the third block, a third partition is provided between the third block and the sedimentation effluent area, and a fourth partition is provided between the sedimentation effluent area and the equipment block; the first partition, the second partition, the third partition and the fourth partition are parallel to each other, have the same length, and both ends are connected to the long side of the biochemical treatment module.

[0008] Optionally, a first partition plate is provided between the anaerobic zone and the primary anoxic zone. The first partition plate has through holes, allowing the effluent from the anaerobic zone to enter the primary anoxic zone for further anoxic treatment. The first partition plate is parallel to the length direction of the biochemical treatment module.

[0009] Optionally, the water inlet distribution area is located close to the first block and its height is less than that of the second block. The area within the second block excluding the water inlet distribution area is a primary aerobic zone.

[0010] The water inlet distribution area is provided with a first partition and a second partition on both sides, with the second partition parallel to the first partition. The other two sides of the water inlet distribution area are the long side of the biochemical treatment module and a third partition, with the third partition parallel to the first partition. There is a space between the third partition and the other long side of the biochemical treatment module, so that the length of the water inlet distribution area is less than the width of the second block.

[0011] Optionally, the water inlet distribution area is provided with an inlet pipe, a first outlet pipe and a second outlet pipe. The inlet pipe is connected to an external regulating tank for inputting sewage into the water inlet distribution area. The first outlet pipe is connected to the anaerobic zone and the second outlet pipe is connected to the secondary anoxic zone. The effluent from the water inlet distribution area is input into the anaerobic zone and the secondary anoxic zone respectively.

[0012] The volume ratio of wastewater input from the influent distribution zone to the anaerobic zone and the secondary anoxic zone is (4-5):1.

[0013] Optionally, a fourth partition plate is provided between the secondary anoxic zone and the secondary aerobic zone. The fourth partition plate has through holes, so that the effluent from the secondary anoxic zone can enter the secondary aerobic zone for further aerobic treatment.

[0014] Optionally, a vertical inlet center cylinder is provided in the center of the sedimentation effluent zone, with the top of the inlet center cylinder higher than the liquid level of the sedimentation effluent zone and the bottom located at the lower part of the sedimentation effluent zone; the effluent pipe of the secondary aerobic zone is connected to the top of the inlet center cylinder, and the effluent from the secondary aerobic zone is input into the inlet center cylinder;

[0015] The bottom of the sedimentation effluent zone is conical to facilitate the discharge of sludge. The bottom of the sedimentation effluent zone is connected to the feed tank through a sludge discharge pipe, and the sludge generated in the sedimentation effluent zone is discharged into the feed tank as raw material.

[0016] The top of the sedimentation effluent zone is equipped with a product water pipe for discharging the biochemically treated product water, which can be reused as recycled water.

[0017] Optionally, the sedimentation effluent zone is equipped with a sludge stripping pipe, which is connected to the anaerobic zone through a sludge return pipe, for returning the sludge from the sedimentation effluent zone to the anaerobic zone to replenish the amount of activated sludge in the anaerobic zone.

[0018] The end of the primary aerobic zone is equipped with a nitrification liquid stripping pipe, which is connected to the primary anoxic zone through a nitrification liquid return pipe to return the nitrification liquid to the primary anoxic zone.

[0019] The aeration blower is connected to the nitrification liquid stripping pipe and the sludge stripping pipe through an air circuit to provide power.

[0020] Optionally, the fermenter is equipped with a stirring device and a heating device to provide heat for the fermentation of materials inside the fermenter and to promote the timely discharge of biogas produced.

[0021] The fermentation tank has a slag discharge port at the bottom for discharging the fermented waste; a drain pipe is connected to the middle and lower part of the fermentation tank for discharging the generated biogas slurry into the biogas slurry tank; and an exhaust port is provided at the top of the fermentation tank, which is connected to the biogas collection tank.

[0022] In the biological treatment module, the aeration blower is the single most energy-intensive device, while the temperature of the influent wastewater is typically 15-25℃. Even after treatment, the effluent still has a temperature above 12℃. The anaerobic fermentation module's fermenter has a heating device, so it also generates heat. This invention provides a heat engine device that utilizes the heat from the wastewater and the heat from the fermenter.

[0023] Optionally, the heat engine device includes a lower heat exchange cylinder, an upper power cylinder, and a main rod. The main rod is detachably connected to the drive shaft of the aeration blower via a coupling, so that the main rod can drive the drive shaft to rotate, thereby driving the blower to rotate.

[0024] The main rod is located above the power cylinder. The heat exchange cylinder is connected to the power cylinder. There is air in the heat exchange cylinder and the power cylinder. The lower part of the heat exchange cylinder is immersed in sewage or directly contacts the top surface of the fermenter. The other parts of the heat exchange cylinder are in the outside air.

[0025] The heat exchange cylinder is equipped with a first piston, and the power cylinder is equipped with a second piston. The first piston is rotatably connected to the main rod through a first connecting rod, and the second piston is rotatably connected to the main rod through a second connecting rod. The first piston and the second piston move up and down due to the thermal expansion and contraction of the gas in the heat exchange cylinder and the power cylinder, which in turn drives the main rod to rotate.

[0026] Optionally, the main rod is a crankshaft, and the connection point between the first connecting rod and the crankshaft and the connection point between the second connecting rod and the crankshaft form a 90° angle, so that the operation of the first piston and the second piston differs by a 90° phase angle. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the biochemical processing module;

[0028] Figure 2 This is a schematic diagram of the anaerobic fermentation module.

[0029] Figure 3 This is a schematic diagram of the combined power unit of a hydrothermal heat engine and a fan.

[0030] Figure 4 This is a schematic diagram showing four states of the combined heat engine and fan power unit during use.

[0031] Figure 5 A schematic diagram illustrating the structure for enhancing the fit between the heat exchange section and the heat exchange cylinder;

[0032] Figure 6 This is a schematic diagram of the bottom surface of the heat exchange cylinder;

[0033] Figure 7 This is a side view of the bottom surface of the heat exchange cylinder;

[0034] Figure 8 This is a schematic diagram of an indirect purging device.

[0035] In the attached diagram, 1-Inlet water distribution zone, 2-Anaerobic zone, 3-Primary anoxic zone, 4-Primary aerobic zone, 5-Secondary anoxic zone, 6-Secondary aerobic zone, 7-Sedimentation effluent zone, 8-Feed tank, 9-Fermentation tank, 10-Biogas slurry tank, 11-Drainage pipe, 12-Equipment block, 13-Aeration blower, 14-First baffle, 15-Second baffle, 16-Third baffle, 17-Fourth baffle, 18-First partition plate, 19-Second partition plate, 20-Third partition plate, 21-Inlet pipe, 22-First outlet pipe, 23-Second outlet pipe, 24-Fourth partition plate, 25-Inlet central cylinder, 26-Sludge stripping pipe, 27-Sludge return pipe, 28-Nitrified liquid stripping pipe, 29-Nitrified liquid return pipe, 30- PLC control unit, 31-Heating device, 32-Slag discharge port, 33-Exhaust port, 34-Coupling, 35-Main rod, 36-Drive shaft, 37-Heat exchange cylinder, 38-Power cylinder, 39-First piston, 40-Second piston, 41-First connecting rod, 42-Second connecting rod, 43-Flywheel, 44-High-temperature water heat exchange tube, 45-First heat exchange plate, 46-Medium-temperature water heat exchange tube, 47-Second heat exchange plate, 48-First high-temperature water pipe, 49-Second high-temperature water pipe, 50-First medium-temperature water pipe, 51-Second medium-temperature water pipe, 52-First bevel gear, 53-Second bevel gear, 54-First rod, 55-Third bevel gear, 56-Fourth bevel gear, 57-Second rod, 58-Pipeline, 59-Wind wheel. Detailed Implementation

[0036] This embodiment provides an integrated energy-saving system for wastewater treatment combined with biogas fermentation, such as... Figures 1-2 As shown, it includes a biochemical treatment module and an anaerobic fermentation module that are connected to each other. The biochemical treatment module includes an influent distribution zone 1, an anaerobic zone 2, a primary anoxic zone 3, a primary aerobic zone 4, a secondary anoxic zone 5, a secondary aerobic zone 6, and a sedimentation effluent zone 7 that are connected in sequence.

[0037] The anaerobic fermentation module includes a feed tank 8, a fermentation tank 9, and a biogas slurry tank 10 connected in sequence. The sedimentation effluent zone 7 is connected to the feed tank 8 through a sludge discharge pipe, and the sludge produced by the biochemical treatment module is discharged into the anaerobic fermentation module as raw material. The fermentation tank 9 is connected to the biogas slurry tank 10 through a drain pipe 11. The biogas slurry tank 10 is connected to the secondary anoxic zone 5 through a carbon addition pipe. The biogas slurry produced by the fermentation tank 9 is discharged into the biogas slurry tank 10 for temporary storage. The biogas slurry can be discharged into the secondary anoxic zone 5 as a carbon source.

[0038] Optionally, the biochemical treatment module is a cuboid, comprising a first block, a second block, a third block, a sedimentation effluent zone 7, and an equipment block 12 of equal width along its length.

[0039] The first block includes an anaerobic zone 2 and a primary anoxic zone 3 arranged side by side; the second block includes an influent distribution zone 1 and a primary aerobic zone 4; the third block includes a secondary anoxic zone 5 and a secondary aerobic zone 6 arranged side by side; the equipment block 12 is equipped with at least one aeration fan 13 for providing oxygen to the primary aerobic zone 4 and the secondary aerobic zone 6.

[0040] A first partition 14 is provided between the first block and the second block, a second partition 15 is provided between the second block and the third block, a third partition 16 is provided between the third block and the sedimentation effluent zone 7, and a fourth partition 17 is provided between the sedimentation effluent zone 7 and the equipment block 12; the first partition 14, the second partition 15, the third partition 16 and the fourth partition 17 are parallel to each other, have the same length, and are connected at both ends to the long side of the biochemical treatment module.

[0041] Optionally, a first partition plate 18 is provided between the anaerobic zone 2 and the primary anoxic zone 3. The first partition plate 18 has through holes, allowing the effluent from the anaerobic zone 2 to enter the primary anoxic zone 3 for further anoxic treatment. The first partition plate 18 is parallel to the length direction of the biochemical treatment module.

[0042] Optionally, the water inlet distribution area 1 is located close to the first block and its height is less than that of the second block. The area in the second block other than the water inlet distribution area 1 is the primary aerobic zone 4.

[0043] The inlet distribution area 1 has a first partition 14 and a second partition 19 on each side, with the second partition 19 parallel to the first partition 14. The other two sides of the inlet distribution area 1 are the long side of the biological treatment module and a third partition 20, which is parallel to the first partition 18. A space is left between the third partition 20 and the other long side of the biological treatment module, so that the length of the inlet distribution area 1 is less than the width of the second block. The space between the third partition 20 and the other long side of the biological treatment module can be used to provide space for the sludge return pipe 27, the first effluent pipe 22, and the second effluent pipe 23.

[0044] Optionally, the water inlet distribution area 1 is provided with an inlet pipe 21, a first outlet pipe 22, and a second outlet pipe 23. The inlet pipe 21 is connected to an external regulating tank for inputting sewage into the water inlet distribution area 1. The first outlet pipe 22 is connected to the anaerobic zone 2, and the second outlet pipe 23 is connected to the secondary anoxic zone 5. The effluent from the water inlet distribution area 1 is input into the anaerobic zone 2 and the secondary anoxic zone 5, respectively.

[0045] The volume ratio of wastewater input from influent distribution zone 1 to anaerobic zone 2 and secondary anoxic zone 5 is (4-5):1.

[0046] Optionally, the portion of the first partition plate 18 facing the primary anoxic zone 3 and located below the inlet water distribution zone 1 is provided with through holes, so that the effluent from the primary anoxic zone 3 can enter the primary aerobic zone 4 for further aerobic treatment.

[0047] The second baffle 15 has through holes facing the primary aerobic zone 4, allowing the effluent from the primary aerobic zone 4 to enter the secondary anoxic zone 5 for further anoxic treatment.

[0048] Optionally, a fourth partition plate 24 is provided between the secondary anoxic zone 5 and the secondary aerobic zone 6. The fourth partition plate 24 is provided with through holes so that the effluent from the secondary anoxic zone 5 can enter the secondary aerobic zone 6 for further aerobic treatment.

[0049] Optionally, a vertical inlet center cylinder 25 is provided in the center of the sedimentation outlet zone 7. The top of the inlet center cylinder 25 is higher than the liquid surface of the sedimentation outlet zone 7, and the bottom is located at the lower part of the sedimentation outlet zone 7. The outlet pipe of the secondary aerobic zone 6 is connected to the top of the inlet center cylinder 25 to input the effluent from the secondary aerobic zone 6 into the inlet center cylinder 25.

[0050] The bottom of the sedimentation effluent zone 7 is conical to facilitate the discharge of sludge. The bottom of the sedimentation effluent zone 7 is connected to the feed tank 8 through a sludge discharge pipe, and the sludge generated in the sedimentation effluent zone 7 is discharged into the feed tank 8 as raw material.

[0051] The top of the sedimentation effluent zone 7 is equipped with a product water pipe for discharging the product water after biochemical treatment. The product water can be reused as recycled water.

[0052] Optionally, the sedimentation effluent zone 7 is provided with a sludge stripping pipe 26, which is connected to the anaerobic zone 2 through a sludge return pipe 27, for returning the sludge from the sedimentation effluent zone 7 to the anaerobic zone 2 to replenish the amount of activated sludge in the anaerobic zone 2.

[0053] The end of the primary aerobic zone 4 is equipped with a nitrification liquid stripping pipe 28, which is connected to the primary anoxic zone 3 through a nitrification liquid return pipe 29, and is used to return the nitrification liquid to the primary anoxic zone 3.

[0054] The aeration blower 13 is connected to the nitrification liquid stripping pipe 28 and the sludge stripping pipe 26 through an air passage to provide power.

[0055] Optionally, the equipment block 12 includes a PLC control device 30, which can control the level gauges and dissolved oxygen monitors in the equalization tank and each zone, thereby controlling the air supply of the aeration blower 13 to each zone, and can also control the sludge supply of the sludge stripping pipe 26 and the liquid supply of the nitrification liquid stripping pipe 28.

[0056] Optionally, the bottom of the anaerobic zone 2, the primary anoxic zone 3, the primary aerobic zone 4, the secondary anoxic zone 5, and the secondary aerobic zone 6 are all equipped with aeration pipes to provide appropriate oxygen concentrations or aerodynamic disturbances to each zone, thereby ensuring the biochemical treatment effect; the aeration pipes of each zone are connected to the aeration blower 13.

[0057] Optionally, the fermentation tank 9 is equipped with a stirring device and a heating device 31 to provide heat for the fermentation of materials inside the fermentation tank 9, while promoting the timely discharge of biogas produced.

[0058] The bottom of the fermentation tank 9 is provided with a slag discharge port 32 for discharging the waste after fermentation; the middle and lower part of the fermentation tank 9 is connected to a drain pipe 11 for discharging the generated biogas slurry into the biogas slurry tank 10; the top of the fermentation tank 9 is provided with an exhaust port 33, which is connected to a biogas collection tank.

[0059] Optional, such as Figures 3-4 As shown, the heat engine device includes a lower heat exchange cylinder 37, an upper power cylinder 38, and a main rod 35. The main rod 35 is detachably connected to the drive shaft 36 of the aeration blower 13 via a coupling 34, so that the main rod 35 can drive the drive shaft 36 to rotate, thereby driving the blower to rotate.

[0060] The main rod 35 is located above the pneumatic cylinder. The heat exchange cylinder 37 is connected to the power cylinder 38. There is air in the heat exchange cylinder 37 and the power cylinder 38. The lower part of the heat exchange cylinder 37 is immersed in sewage or directly contacts the top surface of the fermenter 9. The other parts of the heat exchange cylinder 37 are in the outside air.

[0061] The heat exchange cylinder 37 is equipped with a first piston 39, and the power cylinder 38 is equipped with a second piston 40. The first piston 39 is rotatably connected to the main rod 35 through the first connecting rod 41, and the second piston 40 is rotatably connected to the main rod 35 through the second connecting rod 42. The first piston 39 and the second piston 40 are driven to move up and down by the thermal expansion and contraction of the gas in the heat exchange cylinder 37 and the power cylinder 38, which in turn drives the main rod 35 to rotate.

[0062] Optionally, the cross-sectional area of ​​the heat exchange cylinder 37 is larger than that of the power cylinder 38. The top of the heat exchange cylinder 37 is connected to the bottom of the power cylinder 38. The power cylinder 38 is positioned on the side close to the heat exchange cylinder 37 to facilitate separating the positions of the first connecting rod 41 and the second connecting rod 42 connected to the main rod 35, thus preventing them from affecting each other when they are raised or lowered.

[0063] Optionally, the cross-sectional area of ​​the first piston 39 is smaller than that of the heat exchange cylinder 37, so that there is a gap between the edge of the first piston 39 and the inner wall of the heat exchange cylinder 37, which facilitates the flow of gas up and down in the heat exchange cylinder 37 when the first piston 39 moves up and down.

[0064] The first connecting rod 41 is vertically arranged, and its bottom end is hinged to the upper surface of the first piston 39, while its top end is connected to the main rod 35 through a bearing;

[0065] The first connecting rod 41 passes through the top surface of the heat exchange cylinder 37, and a sealing device is provided at the point where it passes through the top surface to prevent the heat exchange cylinder 37 from leaking air.

[0066] The above configuration allows for more flexible connections between the first connecting rod 41 and the first piston 39, and between the first connecting rod 41 and the main rod 35. The hinged connection between the first connecting rod 41 and the first piston 39 allows the first piston 39 to swing at a certain angle during movement, accommodating the rapid up-and-down flow of gas within the heat exchange cylinder 37 around the first piston 39 without obstruction. The top end of the first connecting rod 41 is connected to the main rod 35 via a bearing, facilitating the adaptation of the first connecting rod 41 to the rotation of the main rod 35 during its up-and-down movement, ensuring smooth rotation of the main rod 35.

[0067] Optionally, the cross-sectional area of ​​the second piston 40 is equal to the cross-sectional area of ​​the power cylinder 38, that is, the edge of the second piston 40 is in close contact with the inner wall of the power cylinder 38, so that the power cylinder 38 is kept airtight when the second piston 40 moves up and down, and the gas is used to push the second piston 40 to do work.

[0068] The second connecting rod 42 is vertically arranged, and its bottom end is fixedly connected to the upper surface of the second piston 40, while its top end is connected to the main rod 35 through a bearing; the top surface of the power cylinder 38 is open and connected to the external environment.

[0069] Optionally, the main rod 35 is a crankshaft, and the connection point of the first connecting rod 41 and the crankshaft and the connection point of the second connecting rod 42 and the crankshaft form a 90° angle, so that the operation of the first piston 39 and the second piston 40 differs by a 90° phase angle.

[0070] For example, the curved rod section on the crankshaft connects the top ends of the first connecting rod 41 and the second connecting rod 42, and the connection points of the first connecting rod 41 and the second connecting rod 42 are distributed along the length of the crankshaft, so that both the first connecting rod 41 and the second connecting rod 42 are vertical; if the cross-section of the curved rod section on the crankshaft can be assembled into a circle, then the connection points of the first connecting rod 41 and the second connecting rod 42 are both on the edge of the circular cross-section (the circular part is a solid rod, and the part is the projection of the solid rod behind or in front onto the circle), and the arc between the two connection points is π / 2, that is, the lines connecting the two connection points to the center of the circle form an angle of 90°.

[0071] Optionally, a flywheel 43 is provided on the main rod 35 near the coupling 34. The main rod 35 passes through the center of the flywheel 43 and is then connected to the coupling 34, allowing the main rod 35 to rotate continuously and stably, steadily and smoothly inputting mechanical energy into the drive shaft 36 of the aeration blower 13. The main rod 35 and the drive shaft 36 are connected by the coupling 34, and the mechanical energy is ultimately transmitted to compressed air through the aeration blower 13 and supplied to various areas through the air passage.

[0072] The heat engine device operates in four cyclical states. Specifically, as shown in the figure, when the system is in state 1, the first piston 39 is located at the top of the heat exchange cylinder 37. At this time, all the air in the heat exchange cylinder 37 is heated by the heat at the bottom, causing it to expand and push the second piston 40 upward. As the system moves from state 1 to state 2, the first piston 39 moves downward, and some air is transferred to the upper part through the gap between the first piston 39 and the heat exchange cylinder 37. The air above the first piston 39 is separated from the lower heat source and comes into contact with the cooler part of the upper part of the heat exchange cylinder 37. The air temperature begins to drop, and the volume begins to shrink. However, at this time, the overall temperature inside the heat exchange cylinder 37 is rising, and the second piston 40 continues to move upward, then the system moves to state 2.

[0073] When the system is in state 2, the first piston 39 is located in the middle of the heat exchange cylinder 37. The air in the upper part of the heat exchange cylinder 37 begins to cool down, while the air in the lower part continues to heat up. The air temperature inside the heat exchange cylinder 37 is in equilibrium, and at this time, the second piston 40 is pushed to its highest point. As the system moves from state 2 to state 3, the overall temperature of the air inside the heat exchange cylinder 37 begins to decrease, its volume contracts, and the external atmospheric pressure pushes the second piston 40 downward, thus moving the system to state 3.

[0074] When the system is in state 3, the first piston 39 is located at the bottom of the heat exchange cylinder 37, and the temperature of all the air in the heat exchange cylinder 37 is decreasing, causing its volume to shrink. At this time, the second piston 40 accelerates its descent. As the system moves from state 3 to state 4, the cold air above the first piston 39 begins to transfer to the lower part, contacting the bottom of the heat exchange cylinder 37, and its temperature begins to rise. However, a large amount of cold air with a continuously decreasing temperature remains above the first piston 39, and the air in the heat exchange cylinder 37 continues to descend, causing the second piston 40 to continue its descent.

[0075] When the system is in state 4, the first piston 39 is located in the middle of the heat exchange cylinder 37. The air in the lower part of the heat exchange cylinder 37 begins to heat up, while the air in the upper part continues to descend. The air temperature inside the heat exchange cylinder 37 remains in equilibrium, and the second piston 40 is pushed to its lowest point. As the system moves from state 4 to state 1, the overall temperature inside the heat exchange cylinder 37 begins to rise, its volume expands, pushing the second piston 40 upward, and then the system moves back to state 1.

[0076] This invention provides a heat engine device that can be in two forms, applied to a biochemical treatment module and an anaerobic fermentation module, respectively. The first type of heat engine device applied to the biochemical treatment module is, for example... Figures 5-8 As shown, optionally, the bottom surface of the heat exchange cylinder 37 is provided with several sets of enhanced heat exchange sections arranged in parallel. The enhanced heat exchange section includes a high-temperature water heat exchange tube 44, a first heat exchange plate 45, a medium-temperature water heat exchange tube 46, and a second heat exchange plate 47 arranged in parallel. The two ends of the high-temperature water heat exchange tube 44 are respectively connected to the top ends of the first high-temperature water tube 48 and the second high-temperature water tube 49. The bottom ends of the first high-temperature water tube 48 and the second high-temperature water tube 49 are located in the water area with higher water temperature in each zone.

[0077] The two ends of the medium-temperature water heat exchange tube 46 are respectively connected to the top of the first medium-temperature water tube 50 and the second medium-temperature water tube 51, and the bottom ends of the first medium-temperature water tube 50 and the second medium-temperature water tube 51 are located in the water area with the second highest water temperature in each zone.

[0078] The first heat exchange plate 45 and the second heat exchange plate 47 have the same structure, and their lower surfaces are in contact with the sewage in the upper part of each zone.

[0079] Further optionally, the bottom ends of the first high-temperature water pipe 48 and the second high-temperature water pipe 49 are each provided with a filter component for filtering the sewage entering the two high-temperature water pipes.

[0080] The heat engine device is equipped with a first control device, which is connected to the first high-temperature water pipe 48 and the second high-temperature water pipe 49 respectively, and is used to control the position of their bottom ends.

[0081] The first high-temperature water pipe 48 is connected to one end of the high-temperature water heat exchange pipe 44 via the first water pump, and the second high-temperature water pipe 49 is connected to the other end of the high-temperature water heat exchange pipe 44 via the second water pump. It is used to input or output high-temperature sewage from each zone into the high-temperature water heat exchange pipe 44.

[0082] Further optionally, the bottom ends of the first medium-temperature water pipe 50 and the second medium-temperature water pipe 51 are each provided with a filter component for filtering the sewage entering the two medium-temperature water pipes.

[0083] The heat engine device is equipped with a second control device, which is connected to the first medium-temperature water pipe 50 and the second medium-temperature water pipe 51 respectively, and is used to control the position of their bottom ends.

[0084] The first medium-temperature water pipe 50 is connected to one end of the medium-temperature water heat exchange pipe 46 via the third water pump, and the second medium-temperature water pipe 51 is connected to the other end of the medium-temperature water heat exchange pipe 46 via the fourth water pump. It is used to input or output the second-highest temperature sewage in each zone into or out of the medium-temperature water heat exchange pipe 46.

[0085] This invention utilizes a high-temperature water heat exchange pipe 44 to introduce wastewater with a relatively high temperature, and a medium-temperature water heat exchange pipe 46 to introduce wastewater with a slightly higher temperature. A first heat exchange plate 45 and a second heat exchange plate 47 are alternately arranged between the high-temperature water heat exchange pipe 44 and the medium-temperature water heat exchange pipe 46. A circulating arrangement of high-temperature wastewater, top-temperature wastewater, slightly higher-temperature wastewater, and top-temperature wastewater is formed on the bottom surface of the heat exchange cylinder 37, allowing wastewater of different temperatures in each zone to be directly transported to the bottom surface of the heat exchange cylinder 37 and exchange heat with the gas inside. The first and second control devices can take various forms and are flexibly positioned (either inside or outside the biochemical treatment module), as long as they can move the aforementioned high-temperature and medium-temperature water pipes.

[0086] Temperature measuring devices are installed in each zone of the biochemical treatment module (except for equipment block 12) to measure the temperature of different water depths in each zone in real time. For the same zone, the upper surface of the sewage dissipates heat from contact with the air and has a lower temperature, while the temperature increases as you go down. The bottom surface of the heat exchange cylinder 37 needs to contact and enter the sewage surface to fully exchange heat with the sewage, so the heat exchange cylinder 37 is best placed in the zone with the highest surface sewage temperature. The bottom ends of the first high-temperature water pipe 48 and the second high-temperature water pipe 49 extend into the lower part or bottom of the zone with the highest water temperature; the bottom ends of the first medium-temperature water pipe 50 and the second medium-temperature water pipe 51 extend into the zone with the second highest water temperature.

[0087] In one specific implementation, high-temperature wastewater enters the high-temperature water heat exchanger 44 through the first high-temperature water pipe 48, and then returns to the lower part or bottom of the same zone along the second high-temperature water pipe 49. When the filter element at the bottom of the first high-temperature water pipe 48 becomes severely clogged due to prolonged sludge filtration, the wastewater is switched to enter the high-temperature water heat exchanger 44 through the second high-temperature water pipe 49, and then returns to the lower part or bottom of the same zone along the first high-temperature water pipe 48. The filter element at the bottom of the second high-temperature water pipe 49 filters the sludge, while simultaneously backwashing the filter element at the bottom of the first high-temperature water pipe 48. In this way, the first high-temperature water pipe 48 and the second high-temperature water pipe 49 are used alternately, and the filter elements or even the entire two high-temperature water pipes are backwashed alternately without interrupting the wastewater heat exchange.

[0088] Alternatively, the upper portions of the high-temperature water heat exchange tube 44 and the medium-temperature water heat exchange tube 46 protrude into the interior of the heat exchange cylinder 37 to promote heat exchange.

[0089] Optionally, the first heat exchange plate 45 is further provided with several upwardly protruding fins that protrude into the interior of the heat exchange cylinder 37. The bottom surface of the fins is flush with the lower surface of the first heat exchange plate 45, and the bottom surface of the fins is open, allowing wastewater below the first heat exchange plate 45 to enter the internal space of the fins and fully exchange heat with the gas in the heat exchange cylinder 37. Since the wastewater below the first heat exchange plate 45 is located at the top or upper part of the wastewater tank, the wastewater contains very little mud and will not cause significant clogging inside the fins. The second heat exchange plate 47 has the same structure as the first heat exchange plate 45.

[0090] Optionally, an indirect purging device is provided below the main rod 35. The indirect purging device includes a first bevel gear 52, a second bevel gear 53, a first rod 55, a third bevel gear 55, a fourth bevel gear 56, a second rod 57, and a windmill 59. The first bevel gear 52 is vertically arranged and sleeved on the end of the main rod 35 away from the flywheel 43. The second bevel gear 53 is horizontally arranged and meshes with the first bevel gear 52. The first rod 55 is vertically arranged and the top of it is sleeved with the second bevel gear 53, and the bottom of the first rod 55 is sleeved with... A horizontal third bevel gear 55 is provided. A fourth bevel gear 56 is provided at the end of the second rod 57 that is horizontally positioned and close to the end of the first rod 55. The fourth bevel gear 56 is vertical and meshes with the third bevel gear 55. A fan wheel 59 is provided at the end of the second rod 57 that is away from the fourth bevel gear 56. The fan wheel 59 rotates and blows towards the top surface of the heat exchange cylinder 37, promoting airflow and continuously carrying away hot air. This is beneficial for heat exchange between the top surface of the heat exchange cylinder 37 and the air above it, and can also effectively disperse the odor generated by the biochemical treatment in each area.

[0091] The indirect purging device is connected to the main rod 35, and the rotation of the main rod 35 is mechanically transmitted sequentially to the first rod 55 and the second rod 57, thereby driving the impeller 59 to rotate. This causes the air above the heat exchange cylinder 37 to flow, continuously carrying away heat and promoting heat exchange. Specifically, when the main rod 35 rotates, it drives the first bevel gear 52 to rotate, which in turn drives the second bevel gear 53 to rotate. The second bevel gear 53 then drives the first rod 55 to rotate, converting the horizontal rotation of the main rod 35 into the vertical rotation of the first rod 55. The first rod 55 then drives the third bevel gear 55 to rotate, which in turn drives the fourth bevel gear 56 to rotate. The fourth bevel gear 56 then drives the second rod 57 to rotate, converting the vertical rotation of the first rod 55 back into the horizontal rotation of the second rod 57. The second rod 57 then drives the impeller 59 to rotate.

[0092] Optionally, the interior of the first piston 39 is hollow, and two opposite sides are provided with openings for connecting to a pipe 58. The pipe 58 extends out of the heat exchange cylinder 37 and into the sewage tank. A fifth pump is connected to the pipe 58 to input sewage into the interior of the first piston 39, so that heat exchange can also occur inside the heat exchange cylinder 37.

[0093] In general, ordinary pistons are solid and have a certain weight. The first piston 39 of this invention is hollow and contains sewage. Its overall weight is about the same as that of a solid piston.

[0094] The structure of the second type of heat engine device applied to the anaerobic fermentation module is the same as that of the heat engine device applied to the biochemical treatment module. The difference is that the bottom surface of the heat exchange cylinder 37 is a flat surface, which facilitates direct contact with the top surface of the fermenter 9. The fermenter 9 is heated inside, and the heat rises upward. The top surface of the fermenter 9 is a good heat exchange position.

[0095] The biogas discharged from the fermenter 9 is introduced into the hollow first piston 39 for heat exchange;

[0096] The indirect purging device is beneficial for timely purging of the very small amount of biogas leaking from above the fermenter 9.

[0097] The integrated energy-saving system may include two aeration blowers 13. The thermal device used in the biochemical treatment module is connected to one aeration blower 13, and the thermal device used in the anaerobic fermentation module is connected to the other aeration blower 13.

[0098] The present invention also provides a method for using the integrated energy-saving system, comprising the following steps:

[0099] (1) Water intake stage: When the level gauge detects that the liquid level in the external regulating tank is high, the PLC control device controls the start of the lift pump to input the sewage in the regulating tank into the water intake distribution area 1 through the water intake pipe 21, and the water intake flow is measured by the flow meter and adjusted to a suitable water intake flow through the valve.

[0100] Wastewater from influent distribution zone 1 enters anaerobic zone 2 and secondary anoxic zone 5 respectively. During this stage, aeration blower 13 is turned off. Driven by the liquid level difference, the mixed liquor in anaerobic zone 2 flows by gravity into primary anoxic zone 3. The mixed liquor in primary anoxic zone 3 flows from below influent distribution zone 1 into primary aerobic zone 4. The mixed liquor in primary aerobic zone 4 flows by gravity into secondary anoxic zone 5. The mixed liquor in secondary anoxic zone 5 flows by gravity into secondary aerobic zone 6. The mixed liquor in secondary aerobic zone 6 is fed into sedimentation effluent zone 7.

[0101] Because the aeration blower 13 was not turned on, the activated sludge in each zone was separated into mud and water under the action of gravity. The supernatant flowed into the sedimentation effluent zone 7, and the effluent from the sedimentation effluent zone 7 was discharged into the external pipe network through the product water pipe.

[0102] (2) Standby time: 2-3 minutes. The purpose is to balance the liquid level difference between the zones and prevent the mud-water mixture in the secondary aerobic zone 6 from entering the sedimentation outlet zone 7 in large quantities after the aeration blower 13 is turned on during the aeration stage, driven by the liquid level difference. The control principle is the same as step (1).

[0103] (3) Aeration stage: Turn on the aeration blower 13 to aerate and oxygenate the primary aerobic zone 4 and the secondary aerobic zone 6 to remove most of the pollutants in the wastewater.

[0104] Open the reflux solenoid valve of the nitrification liquid stripping pipe 28 to reflux the mixed liquor in the primary aerobic zone 4 to the primary anoxic zone 3 through the air-lift action; the aeration stage lasts for 25-30 minutes.

[0105] (4) Secondary standby: Turn off the aeration blower 13. The activated sludge in the mixed liquor of the two aerobic zones will be separated into mud and water under gravity. Control the amount of sludge entering the sedimentation effluent zone 7. The secondary standby time is 5-8 minutes.

[0106] (5) Return stage: Turn on the return solenoid valve of the aeration blower 13 and the sludge stripping pipe 26 to return the bottom sludge of the sedimentation effluent zone 7 to the anaerobic zone 2 through the air stripping action.

[0107] Optionally, in step (1), shutting off the aeration blower 13 can reduce the sludge concentration entering the sedimentation effluent zone 7 as much as possible, and prevent the sludge from floating in the sedimentation effluent zone 7 due to the large amount of dissolved oxygen carried by the activated sludge, and being lost with the water flow, which would ultimately lead to a reduction in the total amount of activated sludge in the biochemical treatment module and exceed the standards for the produced water quality; the time of the influent stage is adjusted according to the amount of sewage, usually about 1-2 minutes.

[0108] Optionally, in step (5), the reflux time is controlled by observing the clarity of the effluent from the sludge reflux pipe 27. If the refluxed wastewater is clear, it indicates that there is less sludge in the sedimentation effluent zone 7, and the reflux time can be shortened. Usually, the time in this stage is controlled to be 3-5 minutes.

[0109] The integrated energy-saving system for wastewater treatment and biogas fermentation operates in accordance with the above five steps for a complete cycle. After step (5) is completed, if the liquid level in the regulating tank is still high, steps (1)-(5) will be automatically repeated until the liquid level in the regulating tank drops to a low level.

[0110] Optionally, in steps (3)-(5), the sedimentation effluent zone 7 discharges the remaining sludge at the bottom into the feed tank 8 through the sludge discharge pipe, and uses the sludge as a fermentation substrate. The feed tank 8 can also be filled with human or animal feces, kitchen waste, and crushed straw. The above materials are mixed in the feed tank 8. The remaining sludge has a large water content, which can fully wet other fermentation substrates, improve the mixing effect, and make the resulting mixture form a viscous paste.

[0111] Feed tank 8 feeds into fermentation tank 9. The mixed substrate ferments under heating and stirring. The biogas produced is collected separately, and the biogas slurry produced is fed into biogas slurry tank 10. Other carbon sources can also be added to biogas slurry tank 10. After mixing, the biogas slurry is quantitatively fed into secondary anoxic zone 5 according to the measured carbon source content in secondary anoxic zone 5.

[0112] The integrated energy-saving system for wastewater treatment combined with biogas fermentation described in this invention can adjust the influent ratio from the influent distribution zone 1 to the anaerobic zone 2 and the secondary anoxic zone 5 according to the quality and quantity of the influent wastewater, and supplement the carbon source of the secondary anoxic zone 5, so that even when the influent quality and quantity fluctuate greatly, water production can still meet the standards. The various zones of the biochemical treatment module are rationally distributed and form an integral cuboid, saving land. In addition, the sludge from the sedimentation effluent zone 7 is not treated and transported off-site, but is used for fermentation to produce biogas and biogas slurry. The biogas slurry is used as a carbon source, saving the dual costs of sludge treatment and carbon source replenishment.

Claims

1. An integrated energy-saving system of sewage treatment combined with biogas fermentation, characterized in that, The integrated energy-saving system comprises a biochemical treatment module and an anaerobic fermentation module connected with each other, the biochemical treatment module comprises, in sequence, a water inlet distribution area, an anaerobic area, a first anoxic area, a first aerobic area, a second anoxic area, a second aerobic area and a sedimentation and water outlet area; The anaerobic fermentation module comprises, in sequence, a feed tank, a fermentation tank and a biogas slurry tank, the sedimentation and water outlet area is connected with the feed tank through a sludge discharge pipe, sludge generated by the biochemical treatment module is used as raw material and discharged into the anaerobic fermentation module, the fermentation tank is connected with the biogas slurry tank through a liquid discharge pipe, the biogas slurry tank is connected with the second anoxic area through a carbon adding pipe, biogas slurry generated by the fermentation tank is temporarily stored in the biogas slurry tank, and the biogas slurry can be discharged into the second anoxic area as a carbon source; The integrated energy-saving system further comprises a heat engine device for utilizing heat of sewage and heat of the fermentation tank; the heat engine device comprises a lower heat exchange cylinder, an upper power cylinder and a main rod, the main rod is detachably connected with a driving shaft of an aeration blower through a shaft coupling, so that the main rod can drive the driving shaft to rotate, and then drive the blower to rotate; The heat exchange cylinder and the power cylinder contain air, the lower part of the heat exchange cylinder is immersed in sewage or directly contacts with the top surface of the fermentation tank, and the other part of the heat exchange cylinder is in the outside air; a first piston is arranged in the heat exchange cylinder, the first piston is rotatably connected with the main rod through a first connecting rod, and the first piston is driven to move up and down by thermal expansion and contraction of the air in the heat exchange cylinder; The bottom surface of the heat exchange cylinder is provided with a plurality of groups of reinforced heat exchange parts arranged side by side, each group of reinforced heat exchange parts comprises, in sequence and side by side, a high-temperature water heat exchange pipe, a first heat exchange plate, a medium-temperature water heat exchange pipe and a second heat exchange plate, both ends of the high-temperature water heat exchange pipe are connected with the top ends of a first high-temperature water pipe and a second high-temperature water pipe respectively, and the bottom ends of the first high-temperature water pipe and the second high-temperature water pipe are located in a water area with a higher water temperature in each area of the biochemical treatment module; Both ends of the medium-temperature water heat exchange pipe are connected with the top ends of a first medium-temperature water pipe and a second medium-temperature water pipe respectively, and the bottom ends of the first medium-temperature water pipe and the second medium-temperature water pipe are located in a water area with a lower water temperature in each area of the biochemical treatment module; The first heat exchange plate and the second heat exchange plate have the same structure and contact with sewage in the upper part of each area through the lower surfaces; The first piston is hollow, and two opposite sides are respectively provided with openings for connecting pipelines, the pipelines pass through the heat exchange cylinder and extend into the sewage pool, so that heat exchange can also occur in the heat exchange cylinder.

2. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 1, characterized in that, The biochemical treatment module is a cuboid, and comprises, along the length direction, a first block, a second block, a third block, a sedimentation and water outlet area and an equipment block with the same width; The first block comprises the anaerobic area and the first anoxic area arranged side by side; the second block comprises the water inlet distribution area and the first aerobic area; the third block comprises the second anoxic area and the second aerobic area arranged side by side; and the equipment block is provided with at least one aeration blower for providing oxygen for the first aerobic area and the second aerobic area; The first block and the second block are provided with a first partition plate, the second block and the third block are provided with a second partition plate, the third block and the sedimentation and water outlet area are provided with a third partition plate, and the sedimentation and water outlet area and the equipment block are provided with a fourth partition plate; the first partition plate, the second partition plate, the third partition plate and the fourth partition plate are parallel to each other, have the same length and are connected with the long side of the biochemical treatment module at both ends.

3. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 2, characterized in that, The first partition plate is provided with a through hole, so that the effluent of the anaerobic zone can enter the first-stage anoxic zone to continue the anoxic treatment; The fourth partition plate is provided with a through hole, so that the effluent of the second-stage anoxic zone can enter the second-stage aerobic zone to continue the aerobic treatment.

4. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 3, characterized in that, The water inlet distribution zone is arranged close to the first zone block and has a height smaller than that of the second zone block, and the region in the second zone block other than the water inlet distribution zone is a first-stage aerobic zone; The water inlet distribution zone is provided with a water inlet pipe, a first water outlet pipe and a second water outlet pipe, the water inlet pipe is connected to an external adjusting tank for inputting sewage into the water inlet distribution zone, the first water outlet pipe is connected to the anaerobic zone, and the second water outlet pipe is connected to the second-stage anoxic zone, and the effluent of the water inlet distribution zone is input into the anaerobic zone and the second-stage anoxic zone respectively; 5. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 4, characterized in that, The volume ratio of the sewage input by the water inlet distribution zone into the anaerobic zone to that input into the second-stage anoxic zone is (4-5):

1. The central part of the sedimentation effluent zone is provided with a vertical water inlet center cylinder, the top of the water inlet center cylinder is higher than the liquid level of the sedimentation effluent zone, and the bottom is located at the lower part of the sedimentation effluent zone; the effluent pipe of the second-stage aerobic zone is connected to the top of the water inlet center cylinder to input the effluent of the second-stage aerobic zone into the water inlet center cylinder; 6. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 5, characterized in that, The bottom of the sedimentation effluent zone is conical to facilitate the discharge of sludge, and the bottom of the sedimentation effluent zone is connected to the feed tank through a sludge discharge pipe to discharge the sludge generated in the sedimentation effluent zone into the feed tank as raw material. The top of the sedimentation effluent zone is provided with a water production pipe for discharging the produced water after biochemical treatment, and the produced water can be reused as reclaimed water. The sedimentation effluent zone is provided with a sludge stripping pipe connected to the anaerobic zone through a sludge backflow pipe to backflow the sludge in the sedimentation effluent zone to the anaerobic zone to supplement the active sludge amount of the anaerobic zone; 7. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 6, characterized in that, The end of the first-stage aerobic zone is provided with a nitrification liquid stripping pipe connected to the first-stage anoxic zone through a nitrification liquid backflow pipe to backflow the nitrification liquid to the first-stage anoxic zone; The aeration fan is connected to the nitrification liquid stripping pipe and the sludge stripping pipe through a gas path to provide power. The inside of the fermentation tank is provided with a stirring device and a heating device to provide heat for the fermentation of the materials in the fermentation tank and to facilitate the timely discharge of the produced biogas; 8. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 1, characterized in that, The bottom of the fermentation tank is provided with a residue discharge port for discharging the waste after fermentation, the middle and lower part of the fermentation tank is connected to a liquid discharge pipe for discharging the produced biogas slurry into a biogas slurry tank, and the top of the fermentation tank is provided with a gas discharge port connected to a biogas collection tank.

9. The integrated energy-saving system for sewage treatment and biogas fermentation according to claim 1, wherein the main rod is above the dynamic gas cylinder, the heat exchange gas cylinder is in communication with the power gas cylinder. The main rod is above the dynamic gas cylinder, the heat exchange gas cylinder is in communication with the power gas cylinder. ​ The power cylinder is provided with a second piston, the second piston is rotatably connected with the main rod through a second connecting rod, and the second piston is driven to move up and down by thermal expansion and cold contraction of gas in the power cylinder, and then the main rod is driven to rotate.

10. The integrated energy saving system of sewage treatment and biogas fermentation according to claim 9, characterized in that, The main rod is a crankshaft, and the connecting point of the first connecting rod and the crankshaft and the connecting point of the second connecting rod and the crankshaft form a 90° angle, so that the operation of the first piston and the second piston is different by 90° phase angle.

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