Method and device for producing nutrient soil using sludge from sewage treatment plant

Abstract

The present invention discloses a method for producing nutrient soil using sewage treatment plant sludge, which includes the following processing steps: 1) The slurry obtained by precipitation separation is transported to an adjustment tank, and an active agent is added to mix with the slurry, and the active agent accounts for 3-5% of the total weight. 2) The material in the adjustment tank is pumped to an elastic filter press device for filter pressing and dehydration to obtain a filter cake with a moisture content of less than 60%, and the filtered water is returned to the sewage treatment plant or directly used as greening and irrigation water. 3) The filter cake is transported to a greenhouse for stacking, and after stacking for 15-20 days, it can be used as nutrient soil for crop planting. This treatment method is to adjust, filter press and ferment the slurry discharged from the urban sewage treatment plant into nutrient soil for crop planting, and the treatment process is simple and the treatment cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of sludge treatment, and in particular to a method and a device for producing nutrient soil by utilizing sludge from a municipal sewage treatment plant. Background Art

[0002] Domestic sewage is wastewater discharged from residents' daily lives, mainly from residential buildings and public buildings, such as residences, offices, schools, hospitals, shops, public places and toilets of industrial enterprises. The pollutants contained in domestic sewage are mainly organic matter and a large number of pathogenic microorganisms. The organic matter in domestic sewage is extremely unstable and easily decomposes to produce a foul odor. Bacteria and pathogens multiply in large numbers with organic matter in domestic sewage as nutrition, which can lead to the spread of infectious diseases. Therefore, domestic sewage must be treated before discharge. With the rapid improvement of urban sewage treatment capacity, the amount of sludge has also increased significantly. The continuous output of sludge every day cannot be digested in time. A large amount of untreated sludge is randomly piled up, which is easy to cause new secondary pollution to the environment.

[0003] At present, the main methods for treating and disposing urban sludge include incineration, landfill, land utilization and composting. The incineration method has complex technology and equipment, high energy consumption, high investment, and is accompanied by air pollution problems. The landfill method is limited by land use and constantly threatens and pollutes the surrounding environment and groundwater. Land utilization and composting have the problem that the sludge discharged from the sewage treatment plant has a high water content, and it is difficult to reduce the water content by dehydration. A large amount of auxiliary materials need to be added, and the treatment cost is high.

[0004] How to properly, safely and at low cost treat sludge with huge output, high water content and complex composition so as to render it harmless and utilize it as a resource has not only become a major issue of concern to the public and the environmental protection community, but also the direction for sludge treatment and disposal to be scientific and reasonable, energy-saving and consumption-reducing, adapted to local conditions and overall coordinated, and lay the foundation for achieving the goals of harmlessness, reduction and resource utilization. Summary of the invention

[0005] The purpose of the present invention is to provide a method and device for producing nutrient soil using sludge from sewage treatment plants. This technology converts the sludge discharged from urban sewage treatment plants into nutrient soil for crop planting after adjustment, filtration and fermentation. The treatment process is simple and the treatment cost is low.

[0006] In order to achieve the purpose of the present invention, the technical solution adopted is:

[0007] A method for producing nutrient soil using sewage treatment plant sludge, comprising the following processing steps:

[0008] 1) The mud obtained by sedimentation separation is transported to the adjustment tank, and the active agent is added to mix with the mud, and the active agent accounts for 3-5% of the total weight.

[0009] 2) The material in the regulating tank is pumped to the elastic filter press device for filtration and dehydration to obtain a filter cake with a moisture content of less than 60%. The filtered water is returned to the sewage treatment plant or directly used as water for greening and irrigation.

[0010] 3) Transport the filter cake to the greenhouse for stacking. After 15-20 days, it can be used as nutrient soil for crop planting. It is best to use a greenhouse that is light-transmitting, rain-proof, and airtight on all sides, and the ground should be hardened.

[0011] Further preferably, YM bacteria is added to the regulating tank, and the amount of YM bacteria added is: 0.5-1 kg per ton of solid material. YM bacteria is added to the regulating tank and mixed with the mud, and the filter cake obtained after filtering by the elastic filter press device contains YM bacteria, which is conducive to the stacking and fermentation of the filter cake. YM bacteria can be purchased commercially.

[0012] Further preferred: the active agent includes wood ash and roasted soil, the weight ratio of wood ash to roasted soil is 1:1, the wood ash is biomass boiler ash, and the roasted soil is waste bricks, unqualified bricks and waste bricks generated by building demolition, which are crushed and passed through an 80-mesh sieve. The wood ash and roasted soil have adsorption and water-permeable bridging functions, which are helpful for filter pressing.

[0013] Further preferred: the device for producing nutrient soil using sludge from a sewage treatment plant comprises a regulating tank, an elastic filter press device and a greenhouse, the elastic filter press device comprises a frame-type bracket, a hydraulic cylinder and an elastic filter press plate, a feed plate is vertically arranged at one end of the frame-type bracket, a feed channel is arranged in the middle of the feed plate, the feed channel is connected to the mud pump through a mud delivery pipe, a filter cloth is covered on the side of the feed plate away from the mud pump, a tunnel-type feed ear is arranged in the middle of the filter cloth, and the tunnel-type feed ear is installed in the feed channel through a retaining ring through a hole; a push plate is suspended on the frame-type bracket, the push plate comprises a sealing pressure plate, a push plate suspension ear is respectively arranged at both ends of the sealing pressure plate, and a mounting shaft supported on the frame-type bracket by a roller is installed between the two push plate suspension ears; a connecting seat is respectively arranged on both sides of the push plate, and the connecting seats on both sides correspond to the two hydraulic The piston shaft ends of the cylinders are connected, and the cylinder seats of the two hydraulic cylinders are connected to the frame-type bracket through cylinder seat connecting ears respectively, and the two hydraulic cylinders are arranged horizontally; a plurality of elastic filter press plates are suspended and installed across the frame-type bracket between the sealing pressure plate and the feed plate, and both sides of the elastic filter press plates are covered with filter cloth with tunnel-type feed ears. The elastic filter press plate comprises a sealing frame and a filter press plate body, and a suspension ear is respectively arranged on both sides of the filter press plate body, and a mounting shaft supported on the frame-type bracket by a roller is installed between the two suspension ears, a boss is arranged in the middle position of the filter press plate body, and a sealing frame is arranged on the periphery of the boss away from the end of the filter press plate body, and a plurality of compression springs are evenly connected and connected between the sealing frame and the filter press plate body, and a through hole is arranged in the middle position of the boss, and the tunnel-type feed ears of the filter cloth on both sides are installed in the through hole through the hole with a retaining ring; a linkage cable is connected between two adjacent mounting shafts.

[0014] Further preferred: a compression spring guide seat is installed on the filter press plate body through mounting ears and connecting bolts, a compression spring guide hole is provided on the compression spring guide seat, the compression spring is inserted into the compression spring guide hole, and the setting of the compression spring guide seat can support the limiting compression spring to avoid bending and deformation of the compression spring during compression.

[0015] Further preferably, the extrusion surface of the boss is provided with a plurality of anti-slip pits, which can avoid displacement of the filter cloth during the extrusion process.

[0016] Further preferably, the sealing surface of the sealing pressure plate is provided with a plurality of anti-slip pits, and the sealing surface of the sealing pressure plate is covered with filter cloth.

[0017] Further preferably, the mesh size of the filter cloth is 110-150 meshes.

[0018] Further preferably, a pressure gauge is installed on the slurry delivery pipe, and the pressure gauge can display the pressure of the slurry delivery.

[0019] This sludge treatment technology has the following advantages:

[0020] 1. This sludge treatment method does not require the addition of flocculants. It can be directly treated with an elastic filter press after adding an active agent. The filter cake obtained can be used as nutrient soil after natural fermentation. The nutrient soil is soft and not easy to harden, which is conducive to plant growth and improves the germination rate of plants. The obtained nutrient soil can be used to grow rice, sugarcane, corn, beans, etc., which can increase production by more than 30%.

[0021] 2. Compared with the traditional filter press, the volume of the filter chamber of the traditional plate and frame filter press is fixed, and its filter pressure is determined by the delivery pressure of the sludge delivery pump; while the membrane filter press with better effect performs secondary filter pressing on the filter chamber through the air diaphragm after the sludge delivery and filtration. Due to the small displacement of the diaphragm, the service life of the membrane plate is short, and the replacement is frequent and the cost is high. The sludge moisture content after filtration by the elastic filter press device is less than 20% lower than that of the sludge after filtration by the membrane filter press. The secondary filtration is completely compressed by the hydraulic cylinder, and the elastic filter plate contracts to compress the sludge in the filter chamber. The hydraulic energy consumption is 3KW, and the working time is 15 minutes. The mechanical energy consumption of the filtration process is low, the time is short, the operation is convenient, the performance is stable, and the service life is long. Through the design and application of elastic filter press plates, the filter press cavity can be further compressed, and the moisture in the sludge in the cavity can be further squeezed out, which better improves the sludge dehydration effect and better solves the shortcomings of traditional filter presses such as low pressure and poor dehydration effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the connection structure of the elastic filter press device adopted;

[0023] Figure 2 yes Figure 1 A schematic top view of a medium elastic filter press device;

[0024] Figure 3 yes Figure 1 A schematic diagram of a left side view of a medium elastic filter press device;

[0025] Figure 4 It is a structural schematic diagram of an elastic filter press plate;

[0026] Figure 5 It is a schematic diagram of the decomposed structure of the elastic filter press plate;

[0027] Figure 6 is a schematic cross-sectional view of an elastic filter press plate;

[0028] Figure 7 It is a schematic diagram of the structure of the feed plate;

[0029] Figure 8 is a schematic cross-sectional view of the feed plate;

[0030] Fig. 9It is a schematic diagram of the structure of the push plate;

[0031] The names corresponding to the numbers in the figure are:

[0032] 1. Frame bracket; 2. Cylinder seat connecting ear; 3. Hydraulic cylinder; 4. Mud pump; 5. Mud pipe; 6. Pressure gauge; 7. Feed plate; 8. Elastic filter plate; 9. Roller; 10. Mounting shaft; 11. Linkage cable; 12. Push plate; 13. Connecting seat; 14. Filter cloth; 15. Sealing frame; 16. Compression spring; 17. Compression spring guide seat; 18. Suspension ear; 19. Mounting ear; 20. Filter plate body; 21. Tunnel feed ear; 22. Anti-slip pit; 23. Boss; 24. Compression spring guide hole; 25. Connecting bolt; 26. Aisle hole; 27. Snap ring for hole; 28. Feed channel; 29. ​​Sealing plate; 30. Push plate suspension ear; 31. Adjustment tank. DETAILED DESCRIPTION

[0033] In order to make the technical solution and advantages of the present application more clear, the technical solution is clearly and completely described below in conjunction with embodiments.

[0034] Example 1

[0035] The following steps can be used to complete the treatment of sludge from urban sewage treatment plants:

[0036] 1) The mud obtained by precipitation separation is transported to the adjustment tank 31, and an active agent is added to mix with the mud, and the active agent accounts for 3% of the total weight. The active agent includes plant ash and roasted soil, and the weight ratio of plant ash to roasted soil is 1:1. The plant ash uses biomass boiler ash, and the roasted soil uses waste bricks and unqualified bricks that are crushed and passed through an 80-mesh sieve before use.

[0037] 2) The material in the regulating tank 31 is pumped to the elastic filter press device for filter pressing and dehydration to obtain a filter cake with a moisture content of less than 60%. The filtered water is returned to the sewage treatment plant or directly used as water for greening and irrigation;

[0038] 3) The filter cake is transported to the greenhouse and stacked. After 20 days of stacking, it can be used as nutrient soil for crop planting.

[0039] The elastic filter press device comprises a frame-type support 1, a hydraulic cylinder 3 and an elastic filter press plate 8. A feed plate 7 is vertically arranged at one end of the frame-type support 1. A feed channel 28 is arranged in the middle of the feed plate 7. The feed channel 28 is connected to the mud pump 4 through a mud delivery pipe 5. A pressure gauge 6 is installed on the mud delivery pipe 5. The mud pump 4 pumps the mud to be filtered into the feed channel 28 through the mud delivery pipe 5. The side of the feed plate 7 away from the mud pump 4 is covered with a filter cloth 14. A tunnel-type feed ear 2 is arranged in the middle of the filter cloth 14. 1, the tunnel-type feed ear 21 is installed in the feed channel 28 through the hole with a retaining ring 27; a push plate 12 is suspended on the frame-type bracket 1, and the push plate 12 includes a sealing pressure plate 29, and a push plate suspension ear 30 is respectively provided at both ends of the sealing pressure plate 29, and a mounting shaft 10 supported on the frame-type bracket 1 through a roller 9 is installed between the two push plate suspension ears 30; a connecting seat 13 is respectively provided on both sides of the push plate 12, and the connecting seats 13 on both sides are correspondingly connected to the piston shaft ends of the two hydraulic cylinders 3, and the two hydraulic cylinders 3 are connected to the piston shaft ends of the two hydraulic cylinders 3. The cylinder seats are connected to the frame-type bracket 1 through the cylinder seat connecting ears 2 respectively. The two hydraulic cylinders 3 are arranged horizontally. The hydraulic cylinders 3 are connected to the hydraulic control system, and the control system controls the operation of the hydraulic cylinders 3; a plurality of elastic filter press plates 8 are suspended and installed across the frame-type bracket 1 between the sealing pressure plate 29 and the feed plate 7. Both sides of the elastic filter press plate 8 are covered with filter cloth 14 with tunnel-type feed ears 21. The elastic filter press plate 8 includes a sealing frame 15 and a filter press plate body 20. A suspension ear 18 is provided on both sides of the filter press plate body 20. The two suspension ears 18 are provided on both sides of the filter press plate body 20. A mounting shaft 10 is installed between the lifting ears 18 and is supported on the frame-type bracket 1 through a roller 9. A boss 23 is arranged in the middle of the filter press plate body 20. The sealing frame 15 is arranged on the outer periphery of the boss 23 away from the end of the filter press plate body 20. A plurality of compression springs 16 are evenly connected between the sealing frame 15 and the filter press plate body 20. A through hole 26 is arranged in the middle of the boss 23. The tunnel-type feed ears 21 of the filter cloth 14 on both sides are installed in the through hole 26 through a retaining ring 27; and a linkage cable 11 is connected between two adjacent mounting shafts 10.

[0040] Example 2

[0041] The difference from Example 1 is that YM bacteria is also added to the adjustment tank 31, and the amount of YM bacteria added is 1 kg for one ton of solid material.

[0042] The filter press plate 20 is connected with a compression spring guide seat 17 through a mounting ear 19 and a connecting bolt 25. The compression spring guide seat 17 is provided with a compression spring guide hole 24, and the compression spring 16 is inserted into the compression spring guide hole 24. The extrusion surface of the boss 23 is provided with a plurality of anti-slip pits 22.

[0043] The sealing surface of the sealing pressure plate 29 is provided with a plurality of anti-slip pits 22 , and the sealing surface of the sealing pressure plate 29 is covered with filter cloth.

[0044] The working principle of the elastic filter press device is as follows: the mud delivery pipe 5 is connected to the bottom of the regulating tank 31, the hydraulic control system works, the piston shafts of the hydraulic cylinders 3 on both sides are retracted, and the push plate 12 is pulled to move forward with the roller 9 as the support point, and the multiple elastic filter press plates 8 are pushed together. The frontmost elastic filter press plate 8 is fitted with the feed plate 7, and the pressure is about 10Mpa. A filter press chamber is formed between the boss 23 of the frontmost elastic filter press plate 8 and the feed plate 7, and a filter press chamber is also formed between the boss 23 of the rear elastic filter press plate 8 and the back of the filter press plate body 20 of the front elastic filter press plate 8. The mud pump 4 The sludge is pumped from the feed channel 28 of the feed plate 7 into the filter press chamber, and the first-level filtration is performed by the pumping pressure. The filtrate passes through the gap between the sealing frame 15 and the boss 23 through the filter cloth 14 and drips downward. When the pumping pressure reaches the set value, the mud pump 4 is stopped, and the hydraulic control system works again to control the piston shaft of the hydraulic cylinder 5 to continue to retract, so that the push plate 12 continues to push the elastic filter press plate 8 forward, the compression spring 16 is squeezed, and the boss 23 moves forward and moves relative to the sealing frame 15, thereby pressing the sludge in the filter press chamber and realizing secondary filtration to squeeze out more water. The maximum pressure is up to 20Mpa. After the secondary filtration is completed, the hydraulic control system works to control the hydraulic cylinder 5 to work, push the push plate 12 to separate from the elastic filter press plate 12, and the compression spring 16 drives the sealing frame 15 to reset. Due to the action of the linkage cable 11, multiple elastic filter press plates 12 are also separated at once, and the frontmost elastic filter press plate 12 is separated from the feed plate 7. The sludge filter cake falls down and is collected, that is, a batch of sludge filtration is completed. The moisture content of the sludge after filtration and dehydration is less than 60%, and it is transported to the sludge fertilizer treatment. Repeat the above steps to filter the next batch of sludge.

[0045] A Guangxi Environmental Protection Technology Co., Ltd. used a plate and frame filter press, a diaphragm filter press and the elastic filter press device used in this application to conduct trial filtration operations. The filtration lasted for 15 minutes, the pumping pressure was 1.3Mpa, and the moisture content of the filter mud was recorded in the following table.

[0046]

[0047] A Guangxi Environmental Protection Technology Co., Ltd. used the obtained nutrient soil to conduct long bean planting experiments in the experimental fields in the same area. One field was planted after laying nutrient soil, and the other field was not laid with nutrient soil. The amount of fertilizer, sowing amount and management method were the same. The results obtained are recorded in the following table.

[0048]

[0049] The above description is not a limitation of the present application, and the present application is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present application should fall within the scope of protection of the present application.

Claims

1. A method for producing nutrient soil using sewage treatment plant sludge, characterized in that: The processing steps include: 1) The mud obtained by sedimentation separation is transported to a regulating tank (31), and an active agent is added to mix with the mud, and the active agent accounts for 3-5% of the total weight; 2) The material in the regulating tank (31) is pumped to an elastic filter press device for filter pressing and dehydration to obtain a filter cake with a moisture content of less than 60%, and the filtered water is returned to the sewage treatment plant or directly used as greening and irrigation water; YM bacteria are also added to the regulating tank (31), and the amount of YM bacteria added is: 0.5 to 1 kg per ton of solid material; 3) The filter cake is transported to the greenhouse and stacked. After 15-20 days of stacking, it can be used as nutrient soil for crop planting; The active agent includes plant ash and roasted soil, the weight ratio of plant ash to roasted soil is 1:1, the plant ash is biomass boiler ash, and the roasted soil is crushed waste bricks and passed through an 80-mesh sieve; The elastic filter press device comprises a frame-shaped support (1), a hydraulic cylinder (3) and an elastic filter press plate (8), wherein a feed plate (7) is vertically arranged at one end of the frame-shaped support (1), a feed channel (28) is arranged at the middle position of the feed plate (7), the feed channel (28) is connected to the mud pump (4) through a mud delivery pipe (5), a filter cloth (14) is installed on the side of the feed plate (7) away from the mud pump (4), a tunnel-type feed ear (21) is arranged at the middle position of the filter cloth (14), and the tunnel-type feed ear (21) is installed in the feed channel (28) through a hole with a retaining ring (27). ) inside; a push plate (12) is suspended and installed on the frame bracket (1), the push plate (12) includes a sealing pressure plate (29), and a push plate suspension ear (30) is respectively provided at both ends of the sealing pressure plate (29), and a mounting shaft (10) supported on the frame bracket (1) by a roller (9) is installed between the two push plate suspension ears (30); a connecting seat (13) is respectively provided on both sides of the push plate (12), and the connecting seats (13) on both sides are connected to the piston shaft ends of the two hydraulic cylinders (3), and the cylinder seats of the two hydraulic cylinders (3) are respectively connected through the cylinder seat connecting ears ( 2) is connected to the frame-type support (1), and the two hydraulic cylinders (3) are arranged horizontally; a plurality of elastic filter press plates (8) are suspended and installed across the frame-type support (1) between the sealing pressure plate (29) and the feed plate (7), and both sides of the elastic filter press plates (8) are covered with filter cloths (14) with tunnel-type feed ears (21). The elastic filter press plates (8) include a sealing frame (15) and a filter press plate body (20), and the two sides of the filter press plate body (20) are respectively provided with a suspension ear (18), and a roller (9) is installed between the two suspension ears (18) and is supported across the frame. A mounting shaft (10) is mounted on a type bracket (1), a boss (23) is arranged at the middle position of the filter press plate body (20), a sealing frame (15) is arranged on the outer periphery of the boss (23) away from the end of the filter press plate body (20), a plurality of compression springs (16) are evenly connected and arranged between the sealing frame (15) and the filter press plate body (20), a through hole (26) is arranged at the middle position of the boss (23), and tunnel-type feed ears (21) of filter cloths (14) on both sides are installed in the through hole (26) through retaining rings (27) through the holes; and a linkage cable (11) is connected between two adjacent mounting shafts (10).

2. The method for producing nutrient soil using sewage treatment plant sludge according to claim 1, characterized in that: A compression spring guide seat (17) is connected and mounted on the filter press plate body (20) via a mounting ear (19) and a connecting bolt (25). A compression spring guide hole (24) is provided on the compression spring guide seat (17), and the compression spring (16) is inserted into the compression spring guide hole (24).

3. The method for producing nutrient soil using sewage treatment plant sludge according to claim 1, characterized in that: The extrusion surface of the boss (23) is provided with a plurality of anti-slip pits (22).

4. The method for producing nutrient soil using sewage treatment plant sludge according to claim 1, characterized in that: The sealing surface of the sealing pressure plate (29) is provided with a plurality of anti-slip pits (22), and the sealing surface of the sealing pressure plate (29) is covered with filter cloth.

5. The method for producing nutrient soil using sewage treatment plant sludge according to claim 1, characterized in that: The slurry delivery pipe (5) is provided with a pressure gauge (6).

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