Denitrification nitrogen removal filter tank based on suspended filter material

Abstract

The utility model provides a denitrification nitrogen removal filter tank based on a suspended filter material, which comprises a tank body, a water inlet area, a filter area and a water collecting and draining area which are communicated with one another are arranged in the tank body from bottom to top, the water inlet area is connected with a water inlet pipe, a water inlet valve is arranged on the water inlet pipe, the suspended filter material is filled in the filter area, and the water collecting and draining area is connected with a water outlet pipe; the bottom of the filter area is connected with a backwashing air distribution pipe, an airflow control valve is arranged on the backwashing air distribution pipe, the water inlet area is connected with a backwashing drain pipe, a drain valve is arranged on the backwashing drain pipe, and the top of the tank body is connected with an exhaust pipe. The suspended filter material is adopted, so that the denitrification efficiency is high, the filling and replacement are convenient, and the possibility of blockage and hardening is low; during backwashing, only air is introduced into the bottom of the filter area, and under the disturbance of airflow and water flow, a biological membrane on the suspended filter material is disintegrated and falls off, so that the backwashing effect is good, a large amount of washing water does not need to be consumed, and automatic switching between sewage treatment and backwashing can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to a denitrification and denitrification filter tank based on suspended filter material. Background Art

[0002] Traditional denitrification filters typically use inorganic rigid media such as ceramsite, slag, or quartz sand. These media have a small particle size (3-6 mm), a relative density greater than water, and are strong, structurally stable, and resistant to deformation. During filtration, the media do not move, maintaining a relatively stable state. This is known as fixed-bed filtration. However, as filtration time increases, biofilms continuously grow on the media surface, the gaps between the media become smaller, and the filtration resistance increases. Therefore, the fixed bed requires backwashing. During backwashing, compressed air or pressurized water is used to loosen the media layer and dislodge any biofilm adhering to the media surface, allowing it to be discharged with the flushing water. During fixed-bed backwashing, due to the media's much higher density than water and the resulting compaction and clogging of the media over long periods of filtration, large amounts of flushing water are required and difficult to rinse thoroughly. Furthermore, excessive backwashing intensity can easily lead to media loss. Utility Model Content

[0003] In response to the deficiencies in the prior art, the utility model provides a denitrification and denitrification filter tank based on suspended filter media. The use of suspended filter media has high denitrification efficiency, is easy to load and replace, and is not prone to clogging and compaction. During backwashing, only air needs to be introduced into the bottom of the filter area. Under the disturbance of air and water flow, the biofilm on the suspended filter media disintegrates and falls off, resulting in a good backwashing effect, without consuming a large amount of flushing water, and capable of realizing automatic switching between sewage treatment and backwashing.

[0004] The technical solutions adopted to achieve the above-mentioned purpose of the present invention are:

[0005] A denitrification and denitrification filter tank based on suspended filter media comprises at least a tank body, wherein the tank body is provided with a water inlet area, a filtration area and a water collection and drainage area which are interconnected from bottom to top, wherein the water inlet area is connected to a water inlet pipe which is provided with a water inlet valve, the filtration area is filled with suspended filter media, and the water collection and drainage area is connected to a water outlet pipe; the bottom of the filtration area is connected to a backwash air pipe which is provided with an air flow control valve, the water inlet area is connected to a backwash drainage pipe which is provided with a drainage valve, and the top of the tank body is connected to an exhaust pipe.

[0006] The water inlet pipe and the water outlet pipe are both provided with pressure gauges to monitor the water inlet pressure and the water outlet pressure.

[0007] The pressure gauges on the inlet pipe and the outlet pipe are both connected to the control system, which is also connected to the inlet valve, the drain valve, and the air flow control valve. The control system controls the opening and closing of the inlet valve, the drain valve, and the air flow control valve according to the pressure difference between the inlet pipe and the outlet pipe, so as to control the automatic switching between sewage treatment and backwashing.

[0008] The suspended filter media is flexible sponge filter media, with a particle size of 30 - 50 mm, and the filling rate of the suspended filter media is 2 / 3 - 3 / 4 of the volume of the filtration area.

[0009] One end of the backwashing cloth air pipe located outside the pool body is connected to an air pump or a compressed air tank.

[0010] The backwashing cloth air pipe is in a "rich" - shaped structure, and ventilation holes are distributed on the backwashing cloth air pipe.

[0011] The inlet area, the filtration area, and the water collection and drainage area are separated by a partition net installed in the pool body, and the mesh size of the partition net is smaller than the size of the suspended filter media.

[0012] One end of the outlet pipe located in the water collection and drainage area is set as a flared structure, and the flared part faces upward. The opening area of the upper plane of the flared part is 1 / 3 - 1 / 2 of the cross - sectional area of the pool body at the same cross - section.

[0013] A metering pump is connected to the inlet pipe, and a certain concentration of reagent is added to the inlet pipe through the metering pump.

[0014] A discharge port is provided on the pool body at the filtration area for filling and replacing the suspended filter media.

[0015] Compared with the prior art, the technical solution provided by the present utility model has the following advantages: (1) In the denitrification and nitrogen removal filter based on suspended filter media provided by the present utility model, suspended filter media is filled. When the sewage comes into full contact with the suspended filter media, the suspended filter media undergoes partial elastic compression, and the gaps between the suspended filter media become smaller, forming a relatively stable filtration layer. At the same time, the suspended filter media is used as a microbial carrier, and denitrifying bacteria are cultivated on its surface and in its internal pores. The denitrifying bacteria use the carbon source in the sewage to reduce nitrate nitrogen to nitrogen gas to achieve nitrogen removal and realize their own proliferation. The denitrification and nitrogen removal efficiency is high. Moreover, the suspended filter media is light in weight, convenient to fill and replace, and the labor intensity is low.

[0016] (2) In the present utility model, suspended filter media is adopted, which is always in a suspended state in the sewage and is not prone to clogging and caking. At the same time, when the biofilm on the suspended filter media increases, only air needs to be introduced to the bottom of the filtration area. The air flows upward, and under the disturbance of the air flow and the water flow, the biofilm on the suspended filter media disintegrates and falls off. The backwashing effect is good, and a large amount of flushing water does not need to be consumed.

[0017] (3) In the present invention, the pressure gauges on the water inlet pipe and the water outlet pipe are connected to the control system. The control system controls the opening and closing of the water inlet valve, the drain valve, and the air flow control valve according to the pressure difference between the water inlet pipe and the water outlet pipe, thereby realizing automatic switching between sewage treatment and backwashing.

[0018] (4) The suspended filter media in the present invention is relatively large in size, and the water inlet area, the filtration area and the water collection and drainage area are separated by a partition net to prevent the suspended filter media from entering the lower water inlet area. At the same time, it can effectively prevent the filter media from being lost when the flushing intensity is too high. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a front view of the denitrification and denitrification filter tank based on suspended filter media provided by the utility model;

[0020] Figure 2 A side view of a denitrification filter tank based on suspended filter media provided by the utility model;

[0021] Figure 3 This is a top view of the backwash cloth air duct in the utility model;

[0022] In the figure: 1- tank body, 2- support leg, 3- water inlet area, 4- filtration area, 5- water collection and drainage area, 6- water inlet pipe, 7- suspended filter media, 8- outlet pipe, 9- bell mouth, 10- backwash cloth air pipe, 11- backwash drainage pipe, 12- exhaust pipe, 13- screen, 14- pressure gauge, 15- discharge port. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The structure of the denitrification and denitrification filter tank based on suspended filter material provided by the utility model is as follows Figure 1-Figure 2 As shown, it includes a pool body 1. In this embodiment, the pool body is composed of a central cylinder and a convex head connected to the upper and lower ends of the cylinder. The bottom of the pool body is connected to a support leg 2 to support the pool body.

[0025] The pool body is provided with a water inlet area 3, a filtration area 4 and a water collection and drainage area 5 which are interconnected from bottom to top. The water inlet area is connected to a water inlet pipe 6, and a water inlet valve is provided on the water inlet pipe. The filtration area is filled with suspended filter material 7, and the water collection and drainage area is connected to a water outlet pipe 8. Specifically, one end of the water outlet pipe located in the water collection and drainage area is configured as a bell mouth 9 structure, and the bell mouth is configured upward, and the flat opening area on the bell mouth is 1 / 3-1 / 2 of the cross-sectional area of ​​the pool body at the same cross section. During sewage treatment, the water inlet valve is opened, and the sewage that has been fully nitrified enters the water inlet area through the water inlet pipe, then flows into the filtration area, and after being treated with suspended filter material, is discharged from the water outlet pipe of the water collection and drainage area to achieve sewage treatment. Preferably, a metering pump (not shown in the figure) is connected to the water inlet pipe, and a certain concentration of reagent (such as methanol, glucose, sodium acetate, etc.) is added to the water inlet pipe by the metering pump, thereby ensuring the carbon source required for denitrification.

[0026] In this embodiment, the suspended filter material is a flexible sponge filter material, such as polyurethane, cellulose and other materials. The flexible sponge has a porous structure, a large specific surface area, and a certain adsorption capacity, which is conducive to the growth and reproduction of denitrifying microorganisms, saves culture time, and significantly improves the denitrification efficiency. The particle size of the suspended filter material is 30-50mm, and the suspended filter material can be spherical or cube-shaped. The filling rate of the suspended filter material is 2 / 3-3 / 4 of the volume of the filter area. When the sewage is fully in contact with the suspended filter material, the suspended filter material undergoes partial elastic compression, and the gaps between the suspended filter materials become smaller, forming a relatively stable filter layer. At the same time, the suspended filter material can be used as a microbial carrier to cultivate denitrifying bacteria on its surface and internal pores. The denitrifying bacteria use the carbon source in the sewage to reduce nitrate nitrogen to nitrogen gas to achieve denitrification and realize their own proliferation. In this embodiment, a discharge port 15 is provided on the pool body at the filter area. The discharge port is a manhole for filling and replacing the suspended filter material.

[0027] In this embodiment, an anti - washing cloth air pipe 10 is connected to the bottom of the filtering area, and an anti - washing drain pipe 11 is connected to the water inlet area. A drain valve is provided on the anti - washing drain pipe. The lower water inlet area is also the anti - washing drainage area. Specifically, an installation hole is provided at the bottom of the water inlet area, and a pipe connecting the inside and outside of the pool body is installed in the installation hole. The anti - washing drain pipe and the water inlet pipe are connected to the pipe through a two - way joint. An exhaust pipe 12 is connected to the top of the pool body. During backwashing, the water inlet valve is closed to stop water inlet. Air is introduced into the bottom of the filtering area through the anti - washing cloth air pipe. The air flows upward and is discharged from the exhaust pipe (nitrogen generated during sewage treatment and air brought in by the sewage are also discharged from the exhaust pipe). Under the disturbance of air flow and water flow, the biofilm on the suspended filter media disintegrates and falls off. After the backwashing is completed, the drain valve is opened, and the backwashing water is discharged from the anti - washing drain pipe at the bottom of the pool body. The drain valve is in the closed state during both sewage treatment and backwashing processes. Since the filter media is in a suspended state, its position can move relatively, and the filter media is easily compressed and deformed. Therefore, only by introducing compressed air, strong contact and collision occur between the filter media, and the biofilm on its surface and inside easily falls off. Without consuming backwashing water, the filter media can be thoroughly cleaned and restored to its filtering function, and no blockage or caking problems will occur.

[0028] In this embodiment, the end of the anti - washing cloth air pipe outside the pool body is connected to an air pump or a compressed air tank. During backwashing, the valve of the air pump or the compressed air tank is opened to introduce air into the anti - washing cloth air pipe. Specifically, an air flow control valve is provided on the anti - washing cloth air pipe to control the air flow rate during backwashing. During sewage treatment, the air flow control valve is closed, and during backwashing, the air flow control valve controls the backwashing intensity. Preferably, the anti - washing cloth air pipe has a "rich" - shaped structure, as Figure 3 shown. Ventilation holes are distributed on the anti - washing cloth air pipe, and air diffuses relatively evenly at the bottom of the filtering area through the ventilation holes; further, the diameter of the ventilation holes is 4 - 5 mm.

[0029] In this embodiment, the water inlet area, the filtering area, and the water collection and drainage area are separated by a partition net 13 installed in the pool body, and the mesh size of the partition net is smaller than the size of the suspended filter media, as shown in Figure 2 . Specifically, a layer of partition net is provided at the connection between the convex head at the lower part of the pool body and the cylinder, and a layer of partition net is provided at the connection between the convex head at the upper part of the pool body and the cylinder. That is, the lower convex head is the water inlet area, the middle cylinder is the filtering area, and the upper convex head is the water collection and drainage area. Through the setting of the partition net, the suspended filter media can be prevented from entering the lower water inlet area. At the same time, during the later backwashing, the biofilm falling off the suspended filter media can enter the lower water inlet area and then be discharged through the anti - washing drain pipe. Further, the mesh diameter of the partition net is about 1 / 3 of the diameter of the suspended filter media. The partition net is made of stainless steel and is fixed to the annular steel plate and the support cross beam around the pool body.

[0030] In this embodiment, pressure gauges 14 are provided on the water inlet pipe and the water outlet pipe to monitor the water inlet pressure and the water outlet pressure. Specifically, the pressure gauges on the water inlet pipe and the water outlet pipe are connected to the control system, and the control system is also connected to the water inlet valve, the drain valve, and the air flow control valve. The control system controls the opening and closing of the water inlet valve, the drain valve, and the air flow control valve according to the pressure difference between the water inlet pipe and the water outlet pipe, thereby controlling the automatic switching of sewage treatment and backwashing.

[0031] During the sewage treatment process, the large-scale formation of biofilm causes the gaps between suspended filter materials to become smaller, thereby increasing the difference between the water inlet pressure and the water outlet pressure. When the pressure difference reaches the design threshold, the water inlet is stopped and the control system starts the backwash program. At this time, the control system closes the water inlet valve, opens the airflow control valve, performs backwashing, and sets the backwash time. After the backwash time is completed, the control system closes the airflow control valve, opens the drain valve, and discharges the backwash water. After a period of time, the control system closes the drain valve, opens the water inlet valve, and continues sewage treatment.

[0032] The working principle of the denitrification and denitrification filter tank based on suspended filter media provided by the utility model is as follows: during sewage treatment, the sewage that has been fully nitrified enters the water inlet area at the lower part through the water inlet pipe, and at the same time, an appropriate amount of reagents (such as methanol, glucose, sodium acetate, etc.) are added to the sewage in the water inlet pipe through a metering pump to supplement the carbon source required for denitrification; the sewage flows upward through the lower separator, fully contacts with the suspended filter media, and gathers upward under the action of water inertia. The suspended filter media serves as a filter layer and a microbial carrier, reducing the nitrate nitrogen in the sewage to nitrogen gas to achieve denitrification; the denitrified sewage passes through the suspended filter media and the upper separator, enters the bell mouth at the upper part of the tank body, and is then discharged along the outlet pipe.

[0033] Over time, denitrifying bacteria grow on the filter media, forming a biofilm. Some biofilms age, narrowing the gaps between the filter media and increasing water flow resistance. When the water flow resistance reaches the set value, backwash mode is initiated. First, the water inlet valve is closed to stop water inflow. This loosens the filter media layer, allowing some to move downward. Then, the airflow control valve is opened. Air is evenly distributed across the entire cross-section of the backwash cloth air pipe below the suspended filter media, moving upward to scrub the suspended filter media. The impact of the airflow and the disturbance of the water flow cause the biofilm on the suspended filter media to disintegrate and fall off, entering the wastewater. After a period of backwashing, the airflow control valve is closed, stopping ventilation. The biofilm will sink and enter the tank through the holes in the lower screen. The drain valve on the backwash drain pipe is then opened to drain the biofilm. At the end of the backwash cycle, the drain valve is closed and the water inlet valve is opened to begin the next cycle.

Claims

1. A denitrification and denitrification filter tank based on suspended filter media, comprising at least a tank body, characterized in that: An inlet area, a filtration area, and a water collection and drainage area are arranged in the pool body from bottom to top and are connected to each other. The inlet area is connected to an inlet pipe, and an inlet valve is arranged on the inlet pipe. Suspended filter media are filled in the filtration area, and the water collection and drainage area is connected to an outlet pipe; the bottom of the filtration area is connected to an air backwashing pipe, and an air flow control valve is arranged on the air backwashing pipe. The inlet area is connected to a backwashing drain pipe, and a drain valve is arranged on the backwashing drain pipe. The top of the pool body is connected to an exhaust pipe.

2. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: Pressure gauges are arranged on both the inlet pipe and the outlet pipe to monitor the inlet pressure and the outlet pressure.

3. The denitrification and denitrification filter tank based on suspended filter material according to claim 2, characterized in that: The pressure gauges on the inlet pipe and the outlet pipe are both connected to a control system, and the control system is simultaneously connected to the inlet valve, the drain valve, and the air flow control valve. The control system controls the opening and closing of the inlet valve, the drain valve, and the air flow control valve according to the pressure difference between the inlet pipe and the outlet pipe, so as to control the automatic switching between sewage treatment and backwashing.

4. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: The suspended filter media are flexible sponge filter media, the particle size of the suspended filter media is 30 - 50 mm, and the filling rate of the suspended filter media is 2 / 3 - 3 / 4 of the volume of the filtration area.

5. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: One end of the air backwashing pipe located outside the pool body is connected to an air pump or a compressed air tank.

6. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: The air backwashing pipe has a "Feng" - shaped structure, and ventilation holes are distributed on the air backwashing pipe.

7. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: The inlet area, the filtration area, and the water collection and drainage area are separated by a partition net installed in the pool body, and the mesh size of the partition net is smaller than the size of the suspended filter media.

8. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: One end of the outlet pipe located in the water collection and drainage area is arranged in a flared structure, and the flared part faces upward. The opening area of the upper plane of the flared part is 1 / 3 - 1 / 2 of the cross - sectional area of the pool body at the same cross - section.

9. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: A metering pump is connected to the inlet pipe, and a certain concentration of reagent is added to the inlet pipe through the metering pump.

10. The denitrification and denitrification filter tank based on suspended filter material according to claim 1, characterized in that: A discharge port is arranged on the pool body at the position of the filtration area for filling and replacing the suspended filter media.

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