A layer filter special for separating flocculation in sewage after flocculation and coagulation

Abstract

The present application relates to a kind of layer filter specially used for flocculation, flocculation in sewage after the separation of flocculation body, with the pool body of top opening, the inside of pool body is separated to form water storage area and water storage area by partition;Water storage area is equipped with water inlet pipe, and electromagnetic valve and water inlet quantity regulating valve are arranged on water inlet pipe;Water storage area is equipped with water outlet hose, and one end of water outlet hose is water inlet, and float is fixedly connected around water inlet;The other end of water outlet hose is water outlet, and water outlet is located outside pool body and is communicated with outside;Water outlet hose is equipped with water outlet quantity regulating valve.The water storage area is transversely arranged with at least one layer of filter bag, and the filter bag is made of monofilament filter cloth;One end of filter bag is equipped with water inlet, and the water inlet is communicated with the water outlet end of water inlet main pipe through transition pipe;Partition bottom is equipped with differential pressure gauge.The present application has simple structure, low filtration pressure, fast filtration speed, clear water outlet, and is especially suitable for small-scale sewage flocculation body separation.

Description

Technical Field

[0001] This invention relates to a layered filter specifically designed for separating flocs in wastewater after flocculation and coagulation aid, belonging to the field of water treatment and environmental protection technology. Background Technology

[0002] In wastewater treatment, it is often necessary to filter flocs (note: a large amount of flocs are generated after flocculation and coagulation aids in wastewater) from small-scale wastewater (such as wastewater from cattle farms) to achieve solid-liquid separation, which facilitates subsequent treatment processes. However, some existing wastewater treatment systems use filtration devices that are too simple in structure, only able to screen out larger solids but unable to effectively remove flocs, resulting in insufficiently clear effluent; others, while capable of filtering and removing flocs, have complex structures, slow filtration speeds, require high filtration pressures, and necessitate large amounts of coagulant, leading to high investment and operating costs, making them less cost-effective for treating small-scale wastewater.

[0003] A search revealed that patent applications CN202210995596.8 and CN115228172A disclose a wastewater sediment filtration device, comprising a shell with an outlet at the bottom; two arc-shaped screens at the upper end of the shell cavity, with the ends of the two screens close to each other inclined downwards; an arc-shaped plate on the outer side of the shell, forming an annular channel with a steel ring and a scraper on the steel ring; a water inlet cylinder penetrating the upper end of the shell, with its lower end connected to the screen cavity; a rotating cylinder inside the upper end of the water inlet cylinder, with a partition fixed on the inner wall of the rotating cylinder; a planetary gear mechanism on the outer side of the rotating cylinder, with the sun gear coaxially fixed to the rotating cylinder, the gear ring fixed to the upper end of the water inlet cylinder, and multiple long rods fixed around the planetary carrier, which, when driven by the planetary carrier, can rotate the long rods, can push the scraper to rotate around the channel. This technical solution is suitable for filtering flocs in settled wastewater. It can promptly remove flocs from the filter screen, ensuring optimal filter screen operation. It scrapes and collects the flocs from the filter screen and transports them outside the device, thus guaranteeing the overall filtration effect and eliminating the need for backwashing, preventing water waste. However, this technical solution has a relatively complex structure and high cost, which is not conducive to reducing the cost of floc separation in wastewater.

[0004] Therefore, there is an urgent need to develop a filtration device that can overcome the above problems and is suitable for separating flocs from small-scale wastewater after flocculation and coagulation aid. Summary of the Invention

[0005] The main objective of this invention is to overcome the problems existing in the prior art and propose a layered filter specifically for floc separation in wastewater after flocculation and coagulation aid. It has a simple structure, low filtration pressure, fast filtration speed, clear effluent, and a filter cake with moderate moisture content, making it particularly suitable for floc separation in small-scale wastewater.

[0006] The technical solution of this invention to solve its technical problem is as follows:

[0007] A layered filter specifically designed for separating flocs in wastewater after flocculation and coagulation aids includes a tank with a top opening. The tank is characterized by internal partitions that create isolated inlet and outlet water storage zones. The inlet water storage zone has an inlet pipe at its top, equipped with a solenoid valve for controlling the inlet's flow and an inlet flow regulating valve for adjusting the inlet water volume. The outlet water storage zone has an outlet hose, one end of which is an inlet. A float is fixedly connected around the inlet, allowing it to float on the surface of the liquid in the outlet water storage zone and remain in communication with it. The outlet hose passes through the lower sidewall of the outlet water storage zone and is sealed to the sidewall. The other end of the outlet hose is an outlet located outside the tank and connected to the outside. The outlet hose is equipped with an outlet flow regulating valve for adjusting the outlet water volume.

[0008] The pool body is also equipped with a main inlet pipe, which passes through a partition and is sealed to the partition. One end of the main inlet pipe is the inlet end, which is fixed to the lower part of the inlet water storage area and keeps in communication with the liquid in the inlet water storage area. The other end of the main inlet pipe is the outlet end and is located in the outlet water storage area. At least one layer of filter bags is arranged horizontally in the outlet water storage area. The filter bags are made of monofilament filter cloth. One end of the filter bag is provided with an inlet, which is connected to the outlet end of the main inlet pipe through a transition pipe. A differential pressure gauge is provided at the bottom of the partition to measure the liquid level difference between the inlet water storage area and the outlet water storage area.

[0009] When in use, the water to be filtered is put into the water storage area through the inlet pipe. Then, under the action of the water pressure of the liquid itself, the water to be filtered enters each filter bag through the main inlet pipe and the transition pipe for filtration. The filtered water from the filter bags enters the water storage area and is finally discharged through the water outlet hose. At the same time, the filter cake is left in the filter bag, which is then removed from the filter bag for subsequent processing.

[0010] The further improved technical solution of this invention is as follows:

[0011] Preferably, the bottom of the water inlet storage area is a sloping surface facing the partition, and the bottom end of the sloping surface coincides with the bottom end of the partition; the water outlet storage area is provided with a filtration area and a water collection area, the filter bag is placed in the filtration area, the water outlet hose is placed in the water collection area, and the bottom of the filtration area is at a higher height than the bottom of the water collection area.

[0012] By adopting the above preferred scheme, the filtration pressure formed by the height difference can be fully utilized by optimizing the height arrangement of the bottom of each zone. This not only improves the filtration rate but also allows the treated water to be discharged from the filter bags and filters as much as possible, reducing the amount of residual water in the filter bags and filters.

[0013] Preferably, the inlet of the water outlet hose is arranged vertically upward, and the inlet is kept level with or below the water level by the action of the float.

[0014] By adopting this preferred solution, the specific arrangement of the water outlet hose inlet can be further optimized, which can better ensure smooth drainage.

[0015] Preferably, the mesh size of the monofilament filter cloth is 150-250 mesh.

[0016] By adopting this preferred solution, the mesh count of the monofilament filter cloth used to make the filter bag can be further optimized, resulting in a better filtration effect.

[0017] Preferably, in the effluent storage area, a water-permeable filter aid plate is provided above and / or below the filter bag; filter bag positioning components are provided at both ends of the filter bag; the filter bag is also provided with a water-sealed zipper for sludge discharge and / or filter bag cleaning.

[0018] By adopting this preferred scheme, the filter bag arrangement and the specific structure of the filter bag itself can be further optimized.

[0019] Preferably, the layered filter has a first state, which is: during filtration, the liquid level difference between the inlet water storage area and the outlet water storage area is controlled; when the liquid level difference is greater than a first set value, the solenoid valve is closed to stop the water intake; when the liquid level difference is less than a second set value, the solenoid valve is opened to start the water intake.

[0020] More preferably, the layered filter also has a second state, which is as follows: when the filter cake thickness reaches or approaches the thickness limit value, the inlet water flow is gradually reduced by controlling the inlet water flow regulating valve, and at the same time, the liquid level difference is always less than the first set value by controlling the outlet water flow regulating valve, until the water inlet completely stops; when the water inlet completely stops, and the lowest water level in the outlet water storage area is lower than the vertical distance of the lowest point of all filter bags by more than the third set value, all filter bags continue to filter water and flow to the lowest point of the outlet water storage area, and the water continues to drain through the outlet hose until no water is filtered out from the filter bags.

[0021] More preferably, a height difference is formed between the lowest point of the filter bag and the lowest point of the bottom of the outlet water storage area, and the height difference is greater than a third set value.

[0022] More preferably, when the mesh count of the monofilament filter cloth is 150-250 mesh, the first setting value is 20±1mm, the second setting value is 14±1mm, so that the average liquid level difference is controlled at 15±1mm; or, the third setting value is at least 20mm, and the thickness limit value is 8±1mm.

[0023] More preferably, the layered filter also has a third state, which is: removing the sludge filter cake from the filter bag for sludge disposal and cleaning the filter bag for reuse.

[0024] By adopting the above preferred scheme, the specific state of the layered filter can be further improved, and the key control technology characteristics of each state can be clarified.

[0025] Compared with existing technologies, the layered filter of the present invention can achieve ultra-low and moderate filtration pressure, with very little pressure applied to the formed flocs. During the filtration process, the flocs and interstitial water remain independent, allowing the interstitial water to flow smoothly from the gaps to the filter cloth and be filtered out. The present invention has low equipment investment, low filtration pressure, fast filtration speed, clear effluent, and moderate moisture content in the formed filter cake. Compared with pressure filtration and centrifugation, it can significantly reduce the amount of coagulant aid used, with savings exceeding 80%. The present invention has a simple structure and moderate single-pass processing capacity, making it particularly suitable for floc separation in small-scale wastewater. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the principle of Embodiment 2 of the present invention. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments. However, the present invention is not limited to the examples given.

[0029] Example 1

[0030] The layered filter of this embodiment has a pool body with an opening at the top. The interior of the pool body includes an inlet water storage area 01 and an outlet water storage area 02, which are separated from each other by a partition 21.

[0031] The top of the water inlet storage area 01 is equipped with a water inlet pipe 03. The water inlet pipe 03 is equipped with a solenoid valve 04 and a water inlet flow regulating valve 05. The solenoid valve 04 is used to control the opening and closing of the water inlet pipe 03, and the water inlet flow regulating valve 05 is used to regulate the amount of water entering the water.

[0032] The outlet water storage area 02 is equipped with an outlet hose 06. One end of the outlet hose 06 is an inlet 07, and a float 08 is fixedly connected around the inlet 07, so that the inlet 07 floats on the surface of the liquid in the outlet water storage area 02 and remains in communication with the liquid. In this embodiment, the inlet 07 is arranged vertically upward and is kept at or below the water level. The outlet hose 06 passes through the lower side wall of the outlet water storage area 02 and is sealed to the side wall. The other end of the outlet hose 06 is an outlet 09, which is located outside the tank and communicates with the outside. The outlet hose 06 is equipped with an outlet flow regulating valve 10 for adjusting the amount of water discharged.

[0033] At least one layer of filter bags 11, made of monofilament filter cloth, is arranged horizontally within the effluent storage area 02 of the pool. One end of each filter bag 11 has an inlet 12, which connects to the outlet end of a main inlet pipe 14 via a transition pipe 13. The main inlet pipe 14 passes through a partition 21 and is sealed to it. The inlet end 15 of the main inlet pipe 14 is fixed to the lower part of the effluent storage area 01. Water-permeable filter aid plates 16 are provided above and / or below the filter bags 11. A differential pressure gauge 17 is provided at the bottom of the partition 21 to measure the liquid level difference between the effluent storage area 01 and the effluent storage area 02 (Note: the water pressure inside the filter bags 11 is determined by this liquid level difference). In addition, the filter bags 11 are equipped with a water-sealed zipper 18 for sludge removal and / or filter bag cleaning.

[0034] Because the filter bags 11 are arranged laterally, filtration is mainly achieved through the upper and lower monofilament filter cloths. During filtration, the size of the flocs on the upper monofilament filter cloth continuously increases, and the gravity they experience also increases. Under controlled low water pressure and low floc concentration, the flocs will automatically separate from the filter cloth, thus giving the upper monofilament filter cloth a self-cleaning function. Simultaneously, for the entire filter bag 11, due to the controlled low water pressure, the flocs and interstitial water inside the filter bag 11 are spaced apart, preventing the formation of a tightly packed filter layer connected by the flocs. The interstitial water is interconnected, directly contacts the filter cloth, and is discharged, thereby achieving continuous and rapid discharge of interstitial water from the flocs.

[0035] The bottom of the inlet water storage area 01 is a sloping surface facing the partition 21, with the bottom end of the slope coinciding with the bottom end of the partition 21. The outlet water storage area 02 has a filtration zone and a collection zone. The filter bag 11 is placed in the filtration zone, and the outlet hose 06 is placed in the collection zone. The bottom of the filtration zone is higher than the bottom of the collection zone; a height difference of more than 20mm is formed between the lowest point of the filter bag 11 and the bottom of the collection zone. This partitioned bottom height arrangement can make full use of the filtration pressure formed by the height difference, which can not only improve the filtration rate, but also discharge as much treated water as possible from the filter bag and filter, reducing the amount of residual water in the filter bag and filter.

[0036] In addition, filter bag positioning elements 19 are provided at both ends of the filter bag 11 in the filtration zone.

[0037] The basic process of filtering wastewater using the filter in this embodiment is as follows: the water to be filtered enters the inlet water storage area 01 through the inlet pipe 03, and then sequentially enters each filter bag 11 through the main inlet pipe 14 and the transition pipe 13 for filtration. The filtered water from the filter bags 11 enters the outlet water storage area 02 and is finally discharged through the outlet hose 06. Afterwards, the sludge filter cake inside the filter bags 11 is removed for sludge disposal, and the filter bags are cleaned for reuse.

[0038] After systematic testing and research, the key control points of the filter in this embodiment were determined to be:

[0039] (1) During filtration, the liquid level difference between the inlet water storage area 01 and the outlet water storage area 02 should be controlled. When the liquid level difference is greater than the first set value, the solenoid valve 04 is closed to stop the water intake; when the liquid level difference is less than the second set value, the solenoid valve 04 is opened to start the water intake. Among them, when the mesh size of the monofilament filter cloth is 150-250 mesh, the first set value can be 20±1mm, and the second set value can be 14±1mm, so that the average liquid level difference is controlled at 15±1mm. Since the water pressure in the filter bag 11 is determined by the liquid level difference between the inlet water storage area 01 and the outlet water storage area 02, the above control points can maintain a moderate and relatively constant filtration pressure in the filter bag 11.

[0040] (2) The thickness of the filter cake formed inside the filter bag 11 should be below the thickness limit value, which is conducive to the discharge of interstitial water in the flocs. A filter layer that is too thick is not conducive to the discharge of interstitial water in the flocs. The thickness limit value can be 8±1mm.

[0041] (3) When the filter cake thickness reaches or approaches the thickness limit, the inlet water flow is gradually reduced by controlling the inlet water flow regulating valve 05, and the liquid level difference is always less than the first set value by controlling the outlet water flow regulating valve 10 until the inlet water completely stops. When the inlet water completely stops and the water level in the outlet water storage area 02 is more than 20mm lower than the vertical distance of the lowest point of all filter bags 11, all filter bags 11 continue to filter water (Note: you can wait for the filter bags to filter out on their own, or you can add extra weights for pressure filtration), and the water flows to the outlet water storage area 02, and the outlet water hose 06 continues to drain water until the filter bags have no water to filter out. This can effectively reduce the water content of the sludge in the filter bags 11, thereby reducing the final amount of sludge to be disposed of.

[0042] Application test example:

[0043] Wastewater from a cattle farm was collected and its COD and suspended solids concentrations were tested. The wastewater was then mixed (using high-concentration cattle farm wastewater, low-concentration cattle farm wastewater, and tap water as needed) to achieve a COD concentration of 15500 mg / L and a suspended solids concentration of 8500 mg / L. Wastewater from soaking kelp was also collected and its COD and suspended solids concentrations were tested. This wastewater was then mixed (using high-concentration kelp soaking wastewater, low-concentration kelp soaking wastewater, and tap water as needed) to achieve a COD concentration of 1600 mg / L and a suspended solids concentration of 25 mg / L. Under stirring conditions, a 10% FeCl3 flocculant solution was gradually added to the cattle farm wastewater (dosage ratio: the mass of suspended solids in the cattle farm wastewater to the mass of FeCl3 in the added flocculant was 10:1). Then, NaOH solution was gradually added to the mixture to induce flocculation. The resulting solution had a pH of 7.3. The floc boundaries were clear, and the interstitial water was transparent. Under stirring conditions, kelp-soaked wastewater was rapidly added to the flocculated water for preliminary coagulation (dosage: volume ratio of cattle farm wastewater to kelp-soaked wastewater was 3.33:1), resulting in a floc equivalent particle size of 0.8–1.5 mm in the resulting solution. Under stirring conditions, 0.1% of a 10 million molecular weight cationic polyacrylamide solution was gradually added to the solution to further aid coagulation (dosage: volume ratio of the solution to the cationic polyacrylamide solution was 36.1:1), resulting in a floc equivalent particle size of 4–6 mm in the resulting solution. This solution was used as pretreated water.

[0044] Approximately 67L of the pretreated water was filtered through the filter described in this embodiment. 90% of the water sample was removed within one minute, and the effluent was clear and transparent. The final filtered water sample was tested and found to have a COD of 9600 mg / L and suspended solids of 20 mg / L. This filtered effluent has removed the vast majority of suspended solids and can be further treated to reduce the COD value.

[0045] In summary, the filter of this embodiment can achieve ultra-low and moderate filtration pressure, with very little pressure applied to the formed flocs. During the filtration process, the flocs and the interstitial water remain independent, allowing the interstitial water to flow smoothly from the gaps to the filter cloth and be filtered out.

[0046] The filter equipment in this embodiment has low investment, low filtration pressure, fast filtration speed, clear effluent, and moderate moisture content in the formed filter cake. Compared with pressure filtration and centrifugation, it can significantly reduce the amount of coagulant aid used, with savings exceeding 80%. At the same time, the filter in this embodiment has a simple structure and moderate single-pass processing capacity, making it particularly suitable for small-scale sewage treatment projects.

[0047] Example 2

[0048] This embodiment is a comparative test of filter cloth filtration with different weaving methods, as well as a filter cloth mesh size screening test.

[0049] 1. Comparative test of monofilament filter cloth and multifilament filter cloth

[0050] The pretreated water used in the application test example in Example 1 was employed.

[0051] Select monofilament filter cloths of 100 mesh, 120 mesh, 150 mesh, 200 mesh, 250 mesh, and 300 mesh, and multifilament filter cloths of 80 mesh, 100 mesh, 150 mesh, 200 mesh, 250 mesh, and 300 mesh. The dimensions of both monofilament and multifilament filter cloths are 300mm × 300mm. After folding, place them into a square filter. The sides and bottom of the filter are made of perforated support plates with an outer frame dimension of 120mm × 120mm and a depth of 60mm. A wire mesh is used as a separator between the filter cloth and the square perforated plate to minimize the impact on filtration speed caused by blocked filter cloth pores. A water receiving container is provided at the bottom of the filter. The liquid level difference between the liquid level inside the filter and the liquid level in the receiving container is denoted as H. The receiving container is pre-filled with an appropriate amount of clean water. The schematic diagram is shown below. Figure 2 As shown.

[0052] 1.1 Monofilament Filter Cloth Filtration Test

[0053] 1.1.1 The filtration results of 100-mesh and 120-mesh monofilament filter cloths are as follows:

[0054] (1) When the liquid level difference H is controlled below 10 mm and the average liquid level difference is 8 mm, it only takes 51 to 53 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the faster the water output speed is. In addition, as the mesh size increases, the filtration time increases slightly and there are a small amount of fine flocculent matter in the water output.

[0055] (2) When the liquid level difference H is controlled at 10-20mm and the average liquid level difference is controlled at 15mm, it only takes 23-27 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the faster the water output speed. In addition, as the mesh size increases, the filtration time increases slightly, the number of flocculents in the water output increases, but the equivalent diameter decreases.

[0056] (3) When the liquid level difference H is controlled at 20-30mm and the average liquid level difference is controlled at 25mm, it takes 78-82 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the faster the water output speed. In addition, as the mesh size increases, the filtration time increases slightly and there are more flocculent substances in the water output.

[0057] (4) When the liquid level difference H is controlled at 30-40 mm and the average liquid level difference is controlled at 35 mm, there are more flocculent substances in the effluent than in (3), and the filtered effluent is already very turbid.

[0058] (5) When the liquid level difference H is controlled above 40 mm, only a small amount of flocculent material is retained, while most of the flocculent material enters the effluent, and the filtration basically fails.

[0059] 1.1.2 The water filtration results of 150-250 mesh monofilament filter cloth are as follows:

[0060] (1) When the liquid level difference H is controlled below 20 mm and the average liquid level difference is controlled at 15 mm, it takes 60 to 70 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the faster the filtration speed is. In addition, as the mesh size increases, the filtration time increases slightly and no flocculent matter is visible in the effluent.

[0061] (2) When the liquid level difference H is controlled at 20-40mm and the average liquid level difference is controlled at 30mm, it takes 180-212 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the slower the water output speed increases. In addition, as the mesh size increases, the filtration time increases slightly and no flocculent matter is visible in the water output.

[0062] (3) When the liquid level difference H is controlled above 40 mm and the average liquid level difference is controlled at 50 mm, the effluent contains a lot of flocculent matter, and the filtration effect begins to fail.

[0063] 1.1.3 The filtration results of the 300-mesh monofilament filter cloth are as follows:

[0064] (1) When the liquid level difference H is controlled below 20mm and the average liquid level difference is controlled at 15mm, it takes 152 seconds. At the same time, the larger the liquid level difference H is, the faster the filtration speed is, and flocculent matter is basically not visible in the effluent.

[0065] (2) When the liquid level difference H is controlled at 20-50mm and the average liquid level difference is controlled at 35mm, it takes 226 seconds. At the same time, the larger the liquid level difference H is, the slower the water flow rate increases, and no flocculent matter can be seen in the water.

[0066] (3) When the liquid level difference H is controlled above 50 mm, it takes 213 seconds to filter 1 liter of water, and the effluent contains a lot of crushed flocculent matter. The greater the liquid level difference H, the higher the concentration of flocculent matter in the effluent; the filtration effect also begins to fail.

[0067] Based on the above test results, it can be seen that when the mesh size of the monofilament filter cloth is selected between 150 and 250 mesh, and the liquid level difference H is controlled below 20 mm, excellent effects such as fast filtration speed, low pressure, and good effluent quality can be achieved.

[0068] Furthermore, during repeated experiments, the fibrous material between the filter pores of the monofilament filter cloth could be removed with simple washing, and the filtration performance was basically the same as when it was first used, essentially replicating the filtration test results before washing.

[0069] 1.2 Multifilament Filter Cloth

[0070] 1.2.1 The filtration results of multifilament filter cloth with a mesh size of 120 or less are as follows:

[0071] (1) When the liquid level difference H is controlled below 20mm and the average liquid level difference is controlled at 15mm, it takes more than 650 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the greater the pressure and the greater the filtration speed. Flocculent matter is basically not visible in the effluent.

[0072] (2) When the liquid level difference H is controlled at 20-30mm and the average liquid level difference is controlled at 25mm, it takes more than 850 seconds to filter 1 liter of water. At the same time, the larger the liquid level difference H is, the greater the pressure, but the water output speed decreases instead, and there are no flocculent substances in the filtered water.

[0073] (3) When the liquid level difference H is controlled above 30 mm and the average liquid level difference is controlled at 45 mm, it takes more than 1500 seconds to filter 1 liter of water, although no flocculent matter is visible in the effluent. After careful observation, it was found that the reason is that under this pressure, the flocculent matter is squeezed into a tight sticky filter layer, which causes the filtration speed to drop significantly.

[0074] Furthermore, during repeated experiments, the multifilament filter cloth did not easily remove the fibrous material and high molecular weight organic matter that had entered the filter cloth even after repeated washing. It could only achieve about 80% of the filtration speed when the cloth was new, and the more times it was used, the slower the filtration speed became.

[0075] Based on the above test results and actual filtration requirements, it was finally determined that a 150-250 mesh monofilament filter cloth should be used for filtration, with the water level difference controlled within 20 mm and the average liquid level difference controlled within 15 mm. This method has the advantages of low filtration pressure, fast filtration speed, and clear effluent water quality.

[0076] 2. Layered filter verification

[0077] The filter bags are made of 150-mesh and 250-mesh monofilament filter cloth. According to the layered filter structure of Example 1, a layer of filter bags is arranged horizontally in the water storage area of ​​the outlet. Filter aid plates are provided above and below the filter bags. The rest of the structure is the same as that of Example 1.

[0078] Effective filtration can be achieved at the top, bottom, and sides of the filter bag. Within the same time frame, the filtration pressure is controlled by maintaining a liquid level difference of less than 20 mm between the inlet and outlet water storage areas and an average liquid level difference of 15 mm. Approximately 67 L of pretreated water from the application test example in Example 1 was used for filtration verification. The verification results are as follows: the total filtration area of ​​both 150-mesh and 250-mesh filter bags is 1.80 square meters. The average inlet flow rate is controlled at 1.5 liters / second, the average filtration volume is 1.5 liters / second, the filtration time is 44 seconds, and the effluent water quality is clear. The final average thickness of the filter cake formed without compression is 6 mm, with a moisture content of approximately 92%. After adding additional weights to the filter aid plate and pressing for 10 minutes, the resulting filter cake thickness is approximately 2.8 mm, with a moisture content of approximately 82%.

[0079] The above verification shows that using 150-250 mesh monofilament filter cloth to make filter bags and applying them to the layered filter in Example 1 can achieve better filtration results.

[0080] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A layered filter specifically designed for separating flocs in wastewater after flocculation and coagulation aid processes, comprising a tank with an open top, characterized in that, The pool is internally divided into an inlet water storage area and an outlet water storage area, which are isolated from each other. The top of the inlet water storage area is equipped with an inlet pipe, which has a solenoid valve for controlling the on / off state of the inlet pipe and an inlet flow regulating valve for adjusting the inlet water volume. The outlet water storage area is equipped with an outlet hose, one end of which is an inlet. A float is fixedly connected around the inlet of the outlet hose, allowing the inlet to float on the surface of the liquid in the outlet water storage area and remain in communication with the liquid. The outlet hose passes through the lower side wall of the outlet water storage area and is sealed to the side wall. The other end of the outlet hose is the outlet, located outside the pool and communicating with the outside. The outlet hose is equipped with an outlet flow regulating valve for adjusting the outlet water volume. The pool body is also equipped with a main inlet pipe, which passes through a partition and is sealed to the partition. One end of the main inlet pipe is the inlet end, which is fixed to the lower part of the inlet water storage area and maintains communication with the liquid in the inlet water storage area. The other end of the main inlet pipe is the outlet end, which is located in the outlet water storage area. At least one layer of filter bags is arranged horizontally in the outlet water storage area. The filter bags are made of monofilament filter cloth. One end of the filter bag is provided with an inlet, which is connected to the outlet end of the main inlet pipe through a transition pipe. A differential pressure gauge is provided at the bottom of the partition to measure the liquid level difference between the inlet water storage area and the outlet water storage area. The layered filter has a first state, which is: during filtration, the liquid level difference between the inlet water storage area and the outlet water storage area is controlled; when the liquid level difference is greater than a first set value, the solenoid valve is closed to stop the water intake; when the liquid level difference is less than a second set value, the solenoid valve is opened to start the water intake. The layered filter also has a second state, which is as follows: when the filter cake thickness reaches the thickness limit value, the inlet water flow is gradually reduced by controlling the inlet water flow regulating valve, and at the same time, the outlet water flow regulating valve is controlled to keep the liquid level difference less than the first set value until the water inlet completely stops; when the water inlet completely stops, and the lowest water level in the outlet water storage area is lower than the vertical distance of the lowest point of all filter bags by more than the third set value, all filter bags continue to filter water and flow to the lowest point of the outlet water storage area, and the water continues to drain through the outlet hose until no water is filtered out from the filter bags.

2. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in claim 1, is characterized in that... The bottom of the water inlet storage area is a sloping surface facing the partition, and the bottom end of the sloping surface coincides with the bottom end of the partition; the water outlet storage area is provided with a filtration area and a water collection area, the filter bag is placed in the filtration area, the water outlet hose is placed in the water collection area, and the bottom of the filtration area is at a higher height than the bottom of the water collection area.

3. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in claim 1, is characterized in that... The inlet of the water outlet hose is arranged vertically upward, and the inlet of the water outlet hose is kept level with or below the water level by the action of the float.

4. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in claim 1, is characterized in that... The mesh size of the monofilament filter cloth is 150-250 mesh.

5. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in claim 1, is characterized in that... Within the effluent storage area, a water-permeable filter aid plate is provided above and / or below the filter bag; filter bag positioning components are provided at both ends of the filter bag; the filter bag is also provided with a water-sealed zipper for sludge discharge and / or filter bag cleaning.

6. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in any one of claims 1 to 5, characterized in that, There is a height difference between the lowest point of the filter bag and the lowest point of the bottom of the outlet water storage area, and this height difference is greater than the third set value.

7. A layered filter for separating flocs in wastewater after flocculation and coagulation aid, as described in claim 6, is characterized in that... When the mesh size of the monofilament filter cloth is 150-250 mesh, the first setting value is 20±1mm and the second setting value is 14±1mm, so that the average liquid level difference is controlled at 15±1mm. Alternatively, the third setting value is at least 20 mm, and the thickness limit value is 8 ± 1 mm.

8. A layered filter specifically designed for floc separation in wastewater after flocculation and coagulation aid, as described in any one of claims 1 to 5, characterized in that, The layered filter also has a third state, which is: removing the sludge filter cake from the filter bag for sludge disposal and cleaning the filter bag for reuse.

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