An alternating multi-stage aeration biological filter device and method for treating domestic sewage

Abstract

The present invention discloses an alternating multi-stage aerated biological filter device and method for treating domestic sewage, comprising: selecting any one filter to continuously inlet water; the first stage: the filter is kept to only inlet water but not outlet water to preliminarily treat the domestic sewage, while the other filter is backwashed, and the backwash effluent is deeply treated by a sedimentation tank and a third filter; the second stage: after the backwashing of the backwashed filter is completed, the filter that keeps inletting water performs preliminarily treatment on the domestic sewage, the effluent of the filter that keeps inletting water is further treated by the backwashed filter, and the effluent after further treatment is deeply treated by a sedimentation tank and a third filter; reselecting a different filter to alternately inlet water, and repeating the above steps. The present invention performs backwashing while continuously inletting water, and performs multi-stage aerobic and anoxic reactions and integrated precipitation; by alternately inletting water to the filters in different modes, the high biological abundance of the filters is maintained, and the removal rate of pollutants in low carbon-nitrogen ratio domestic sewage is improved.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment design, to sewage treatment equipment and a treatment method, and in particular to an alternating multi-stage aeration biological filter device for treating domestic sewage and a method thereof. Background Art

[0002] Domestic sewage is wastewater discharged from daily life, primarily from residential and public buildings, such as residences, government offices, schools, hospitals, shops, public places, and industrial restrooms. Pollutants in domestic sewage come from a variety of sources, including washing water, sewage, and feces. These pollutants primarily contain organic matter such as carbohydrates, proteins, amino acids, and fats, as well as plant nutrients such as nitrogen and phosphorus. The composition of these pollutants results in a low carbon-to-nitrogen ratio in domestic sewage during treatment. Therefore, an external carbon source is required during treatment to provide the microorganisms with the growth factors necessary to further remove pollutants.

[0003] Domestic sewage is commonly treated using the activated sludge process. The advantages of this process include a mature process, extensive operational experience, high organic matter removal rates, high shock load resistance, and good sludge settling performance. However, its disadvantages are also significant, including large land occupation, high sludge production, high energy consumption, and low nitrogen and phosphorus removal efficiency.

[0004] Therefore, relevant technology and equipment innovations are urgently needed to solve the problem of low carbon-nitrogen ratio domestic sewage treatment. Summary of the Invention

[0005] In view of the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide an alternating multi-stage aerated biological filter device and method for treating domestic sewage. The present invention is a process of alternating water inlet, automatic control, and integrated treatment, which realizes multi-stage aerobic and anoxic treatment and integrates sedimentation function in the overall flow-pushing process, thereby improving the removal rate of pollutants in low carbon-nitrogen ratio domestic sewage.

[0006] The technical solutions of the present invention are as follows:

[0007] An alternating multi-stage aerated biological filter device for treating domestic sewage comprises a functional area and an external structure of the functional area; the functional area comprises mutually independent filter tanks A, B, and C, and a sedimentation tank, wherein filter tanks A, B, and C are each provided with an upper filler layer, a branch pipe of a middle aeration pipe, a lower filler layer, a supporting layer, and filter bricks in sequence from top to bottom; the external structure of the functional area comprises an inlet pipe, a sedimentation outlet pipe, a sedimentation inlet pipe, a vent pipe, a main pipe of the middle aeration pipe, a water and air distribution box, a filter tank connecting pipe serving as a backwash inlet pipe, a backwash inlet pipe, and a clarified outlet pipe, which are respectively interconnected with filter tanks A, B, C, and the sedimentation tank.

[0008] Furthermore, the outer sides of the filter tanks A, B and C are all equipped with water and air distribution boxes. The water and air distribution boxes are used to evenly distribute the backwash water and air to the filter bricks during the backwash state; and to combine the effluent collected by the filter bricks and discharge them when the effluent is clarified.

[0009] Furthermore, the water inlet pipe, the middle aeration pipe, the filter tank connecting pipe serving as the backwash water inlet pipe, the backwash air inlet pipe and the clarified water outlet pipe are respectively connected to filter tank A, filter tank B and filter tank C; the vent pipe, the sedimentation water outlet pipe and the sedimentation water inlet pipe are respectively connected to filter tank A, filter tank B, filter tank C and the sedimentation tank.

[0010] Furthermore, the supporting layer is made of crushed stone or other materials with sufficient strength and porosity; the materials of the lower packing layer and the upper packing layer are particles with excellent phosphorus removal function; the filter bricks are used to evenly distribute water and air to the supporting layer, the lower packing layer and the upper packing layer for the second and third times of backwash water and air intake, and to collect clarified water.

[0011] Furthermore, a radial flow pipe is erected in the center of the sedimentation tank, and a sedimentation outlet weir is set at the upper part of the sedimentation tank.

[0012] Furthermore, the filter tank A, filter tank B, filter tank C and sedimentation tank in the functional area are arranged in a straight line or in a field shape, and can be arranged according to the terrain.

[0013] A method for treating domestic sewage in an alternating multi-stage manner using any one of the above-mentioned alternating multi-stage biological aeration filter devices for treating domestic sewage comprises:

[0014] (1) Select any filter to continuously infuse water;

[0015] (2) First stage: The filter tank only takes in water but does not discharge water to perform preliminary treatment of domestic sewage, while another filter tank performs backwashing. The backwash effluent is precipitated in the sedimentation tank and then deeply treated in the third filter tank;

[0016] (3) Second stage: After the backwashing of the backwashing filter is completed, the filter holding water inlet performs preliminary treatment on the domestic sewage, and the effluent of the filter holding water inlet is further treated by the backwashing filter. The effluent after the further treatment is then precipitated in the sedimentation tank and subjected to deep treatment in the third filter;

[0017] (4) Reselect different filter tanks to alternately inlet water, and repeat steps (1) to (3) to maintain high biological abundance in the filter tanks and improve the removal rate of pollutants in low carbon-nitrogen ratio domestic sewage.

[0018] Furthermore, in the first stage: when water is selected to enter any filter, the water in the filter flows from top to bottom, passing through the aerobic treatment of the upper packing layer, the anoxic treatment of the lower packing layer, the support layer and the filter bricks in sequence, and the middle aeration pipe continuously provides oxygen to the upper packing layer, and the filter performs preliminary treatment on the pollutants in the sewage;

[0019] When the filter tank is filled with water, the other filter tank is backwashed in an air-water backwashing mode; the backwashing water flows from the sedimentation inlet pipe into the radial flow pipe of the sedimentation tank for static sedimentation, and the sedimentation water overflows to the sedimentation outlet weir and flows into the third filter tank from the sedimentation outlet pipe;

[0020] The water in the third filter tank flows from top to bottom, passing through the aerobic treatment of the upper filler layer, the anoxic treatment of the lower filler layer, the supporting layer and the filter bricks in turn. The middle aeration pipe continuously provides oxygen to the upper filler layer. At this time, the sewage undergoes an aerobic and anoxic process, and the pollutants in the sewage are deeply treated. The sewage after deep treatment meets the discharge requirements and is discharged from the clarification outlet pipe nearby.

[0021] Furthermore, in the second stage: after the backwashing of the backwashing filter is completed, the effluent of the filter holding the water inlet is collected through its filter bricks and enters the water distribution and air distribution box of the backwashing filter through the filter connecting pipe and the backwashing water inlet pipe. The effluent is then evenly distributed from the filter bricks of the backwashing filter to the supporting layer, the lower packing layer and the upper packing layer from bottom to top. The middle aeration pipe continuously provides oxygen to the upper packing layer to further treat the pollutants in the sewage.

[0022] The effluent after further treatment enters the radial flow pipe of the sedimentation tank from the sedimentation inlet pipe for static sedimentation, and the sedimentation effluent overflows to the sedimentation effluent weir and flows into the third filter tank from the sedimentation effluent pipe;

[0023] The water in the third filter tank flows from top to bottom, passing through the aerobic treatment of the upper filler layer, the anoxic treatment of the lower filler layer, the supporting layer and the filter bricks in turn. The middle aeration pipe continuously provides oxygen to the upper filler layer to deeply treat the pollutants in the sewage. The sewage after deep treatment meets the discharge requirements and is discharged from the clarification outlet pipe nearby.

[0024] Furthermore, when the amount of sludge in the sedimentation tank reaches a high level, a sludge pump is used to pump it out for external disposal;

[0025] When the device needs to be moved to another location for operation, the water in the functional area is drained from the drain pipe and the device can be transported by vehicle.

[0026] The present invention has the following advantages and positive effects:

[0027] (1) Regarding “alternation”: The present invention switches between different modes and alternately feeds water into different biological aerated filters (such as filter A-filter B-sedimentation tank-filter C, filter B-filter A-sedimentation tank-filter C, and filter C-filter B-sedimentation tank-filter A), thereby providing nutrients with raw water to ensure the same richness of microorganisms in different filters, thereby further ensuring the treatment efficiency of the equipment.

[0028] (2) Regarding "multi-stage": First, the present invention provides multiple biological aeration filters. Through the continuous treatment of multiple biological aeration filters, the entire device of the present invention achieves multi-stage treatment of domestic sewage. Second, each biological aeration filter of the present invention is provided with an upper packing layer, a lower packing layer, a support layer, and filter bricks from top to bottom. Water flows from top to bottom and sequentially passes through the aerobic treatment of the upper packing layer, the anoxic treatment of the lower packing layer, and the collected effluent of the filter bricks, completing the multi-stage treatment of each biological aeration filter.

[0029] (3) The present invention backwashes the filter tank while continuously taking in water, thus achieving continuous operation of the equipment while ensuring the quality of the effluent. After the backwash is completed, a filter tank is used to treat the backwash effluent to achieve discharge standards.

[0030] (4) The present invention uses the Internet of Things technology to enable the equipment to operate automatically and achieve unattended operation.

[0031] (5) The present invention is an integrated device with integrated sewage treatment function, can be transported by vehicle, and can avoid interference from construction boundary conditions, thereby achieving rapid installation on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the overall structural diagram of the device of the present invention;

[0033] Figure 2 is a cross-sectional view of the device of the present invention;

[0034] Wherein: 1-water inlet pipe, 2-radial flow pipe, 3-sedimentation outlet pipe, 4-sedimentation outlet weir, 5-vent pipe, 6-sedimentation inlet pipe, 7-middle aeration pipe, 8-water and air distribution box, 9-filter tank connecting pipe and backwash inlet pipe, 10-backwash inlet pipe, 11-clarification outlet pipe, 12-upper packing layer, 13-lower packing layer, 14-support layer, 15-U-shaped filter brick;

[0035] A-Filter tank A, B-Filter tank B, C-Filter tank C, D-Sedimentation tank. DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings.

[0037] The invention relates to an alternating multi-stage aeration biological filter device for treating domestic sewage. The device is a reaction unit which is controlled by an electric valve to realize continuous water inlet and simultaneous backwashing, and performs multi-stage aerobic and anoxic reactions and integrated precipitation.

[0038] Example 1:

[0039] An alternating multi-stage aeration biological filter device for treating domestic sewage comprises a functional area (including internal components of the functional area) and an external structure of the functional area.

[0040] Among them, the functional areas include filter tank A, filter tank B, filter tank C and sedimentation tank D. The functional areas can be arranged in a straight line, in a field or in other ways, and can be flexibly arranged according to the site conditions. Figure 1 As shown, the functional areas of this embodiment are arranged in a line, including filter tank A, filter tank B, sedimentation tank D and filter tank C from left to right.

[0041] Among them, Figure 1 As shown, the functional area's external structure includes: an inlet pipe 1, a sedimentation outlet pipe 3, a vent pipe 5, a sedimentation inlet pipe 6, the main pipe of the central aeration pipe 7, a water distribution and air distribution box 8, a filter tank connecting pipe serving as a backwash inlet pipe 9, a backwash inlet pipe 10, and a clarified outlet pipe 11. The device's main body (functional area) and the water distribution and air distribution box 8 are made of carbon steel or other materials with equivalent properties. The functional area's external structure also includes a backwash pump, a backwash fan, an inlet pump, a sludge pump, and electric valves.

[0042] The water inlet pipe 1, the middle aeration pipe 7, the filter tank connecting pipe and backwash water inlet pipe 9, the backwash air inlet pipe 10 and the clarified water outlet pipe 11 are respectively connected to the filter tank A, the filter tank B and the filter tank C.

[0043] The vent pipe 5, the sedimentation outlet pipe 3, and the sedimentation inlet pipe 6 are connected to the filter tank A, the filter tank B, the filter tank C and the sedimentation tank D respectively.

[0044] According to the head loss calculation of the treatment scale, the elevations of different functional pipes such as the water inlet pipe 1, the sedimentation water inlet pipe 6 and the clarification water outlet pipe 11 are calculated, holes are opened at the corresponding positions on the functional areas, and the corresponding pipes and electric valves are installed.

[0045] Water and air distribution boxes 8 are installed outside the functional zones' filter tanks A, B, and C. These boxes, during backwashing, evenly distribute the incoming water and air to the U-shaped filter bricks 15. Secondly, during clarified water discharge, they combine the effluent from the U-shaped filter bricks 15 before discharging it. Furthermore, the installation position of the water and air distribution boxes 8 is determined by the installation location of the U-shaped filter bricks 15. The hollow box 8 connects to the U-shaped filter bricks 15 via perforated pipes. The length-to-width ratio of the box 8 must cover the pipes connecting the U-shaped filter bricks 15 within the filter tanks.

[0046] Among them, Figure 2 As shown, the internal components of the functional area include: radial flow pipes 2, sedimentation weir 4, branches of the middle aeration pipe 7, upper packing layer 12, lower packing layer 13, supporting layer 14 and U-shaped filter bricks 15.

[0047] A radial flow pipe 2 is installed vertically in the center of sedimentation tank D. Its diameter is designed based on the treatment capacity and water flow rate. It should be at least 0.3 m from the bottom of sedimentation tank D, a distance consistent with the sludge settling volume. It should be made of stainless steel or other corrosion-resistant materials.

[0048] A sedimentation weir 4 is installed at least 0.5 m from the top of sedimentation tank D. Its installation position is determined by the previously calculated opening locations of the functional pipes in sedimentation tank D. This weir 4 is a movable device, and its height can be adjusted based on site conditions (water depth). The opening of the weir 4 is designed based on the inlet flow rate.

[0049] U-shaped filter bricks 15, a supporting layer 14, a lower packing layer 13, a branch pipe of the middle aeration pipe 7 and an upper packing layer 12 are arranged in filter tanks A, B and C from bottom to top.

[0050] The supporting layer 14 is made of crushed stone or other materials with sufficient strength and porosity, and its pore diameter is larger than that of the lower filler layer 13 .

[0051] The materials of the lower packing layer 13 and the upper packing layer 12 are particles with excellent phosphorus removal function (the above-mentioned particles with phosphorus removal function are prepared according to the production method of biochar ceramsite particle filler in patent ZL 202211109432.7, which will not be repeated here). At the same time, the particles have a large specific surface area and can provide an attachment site for microbial growth.

[0052] The branch pipes of the middle aeration pipe 7 in filter tank A, filter tank B and filter tank C are in the form of perforated aeration pipes.

[0053] The U-shaped filter brick 15 is used to evenly distribute the backwash water and air to the supporting layer 14, the lower packing layer 13 and the upper packing layer 12 for the second and third times; and to collect the clarified water.

[0054] Example 2:

[0055] The process of performing alternating multi-stage treatment of domestic sewage using the alternating multi-stage biological aeration filter device for treating domestic sewage in Example 1 is as follows:

[0056] For example, first select mode 1: filter A-filter B-sedimentation tank D-filter C mode operation:

[0057] (1) When the elevation of the incoming water is higher than the elevation of the device, gravity water is used (or when the elevation of the incoming water is lower than the elevation of the device, a water pump is used to feed water). The incoming water is controlled by an electric valve to achieve water inflow into filter A (filter A in the following steps always remains in a water-filled state).

[0058] (2) The first stage: Filter A only takes in water but does not discharge water to perform preliminary treatment of domestic sewage. At the same time, filter B performs backwashing. The backwash effluent is precipitated in sedimentation tank D and further treated in filter C.

[0059] Specifically: when water enters filter A (at this time, filter A does not discharge water and maintains water storage), the pollutants in filter A diffuse downward and pass through the upper packing layer 12 (aerobic treatment), the lower packing layer 13 (anoxic treatment), the supporting layer 14 and the U-shaped filter brick 15 in sequence. The middle aeration pipe 7 continuously provides oxygen to the upper packing layer 12. At this time, the sewage undergoes aerobic and anoxic processes, and the pollutants in the sewage are preliminarily treated.

[0060] When water enters the filter tank A, the filter tank B is backwashed, and the backwashing method is air-water backwashing.

[0061] Backwash effluent, controlled by an electric valve, enters radial flow pipe 2 of sedimentation tank D from sedimentation inlet pipe 6 for static sedimentation. The effluent overflows onto sedimentation outlet weir 4 and, controlled by an electric valve, flows through sedimentation outlet pipe 3 into filter tank C. The water in filter tank C flows downward, sequentially passing through upper packing layer 12 (aerobic treatment), lower packing layer 13 (anoxic treatment), support layer 14, and U-shaped filter bricks 15. Central aeration pipe 7 continuously supplies oxygen to upper packing layer 12. The wastewater undergoes both aerobic and anoxic processes, deeply treating pollutants within it. After deep treatment, the wastewater meets discharge requirements and is discharged from the nearest clarification outlet pipe 11.

[0062] (3) The second stage: After the backwash of filter B is completed, filter A performs preliminary treatment on the domestic sewage, and the effluent of filter A is further treated by filter B. The effluent of filter B is then precipitated in sedimentation tank D and deeply treated in filter C:

[0063] Specifically, after the backwash of the above-mentioned filter tank B is completed, the sewage is treated aerobically and anoxically in filter tank A from top to bottom, and then is collected from the U-shaped filter brick 15 of filter tank A through the control of the electric valve, and then enters the water distribution and air distribution box 8 of filter tank B through the filter tank connecting pipe and backwash inlet pipe 9 controlled by the electric valve. The preliminary treated sewage is evenly distributed from the U-shaped filter brick 15 to the supporting layer 14, the lower packing layer 13 and the upper packing layer 12 in the filter tank B. The middle aeration pipe 7 continuously provides oxygen to the upper packing layer 12. At this time, the sewage undergoes anoxic and aerobic process, and the pollutants in the sewage are further treated.

[0064] The effluent from filter tank B is controlled by an electric valve to enter the radial flow pipe 2 in the sedimentation tank D from the sedimentation inlet pipe 6 for static sedimentation. The sedimentation effluent overflows to the sedimentation effluent weir 4 and is controlled by an electric valve to flow into filter tank C from the sedimentation effluent pipe 3. The water flows from top to bottom, passing through the upper packing layer 12 (aerobic treatment), the lower packing layer 13 (anoxic treatment), the supporting layer 14 and the U-shaped filter brick 15 in turn. The middle aeration pipe 7 continuously provides oxygen to the upper packing layer 12. At this time, the sewage undergoes an aerobic and anoxic process, and the pollutants in the sewage are deeply treated. The sewage after deep treatment meets the discharge requirements and is discharged nearby from the clarification outlet pipe 11.

[0065] (4) The above is the processing operation process under one mode. Then reselect a mode and repeat the above steps (1)-(3). By switching operations under different modes, the richness of microorganisms in different filter pools is guaranteed to be the same, further ensuring the processing efficiency of the filter pool.

[0066] When the sludge in sedimentation tank D reaches a certain amount, it is pumped out with a sludge pump for external disposal.

[0067] When the equipment needs to be moved to another place for operation, the water is drained from the drain pipe 5 through the electric valve control, and then it can be transported by vehicle.

[0068] The alternating multi-stage aerated biological filter apparatus and method for treating domestic sewage of this embodiment, controlled by an electric valve, achieves continuous water inflow and simultaneous backwashing, and performs multi-stage aerobic and anoxic reactions and integrated sedimentation units. Furthermore, the apparatus features functional integration, good sealing and no leakage, quick installation, and immunity to environmental factors. Furthermore, it is flexible and can be operated in different locations depending on the equipment's conditions. In summary, the alternating multi-stage aerated biological filter apparatus and method for treating domestic sewage of this embodiment can meet engineering construction needs and applications.

[0069] Example 3:

[0070] The parts that are the same as those in Example 2 will not be described in detail in this example.

[0071] First select mode 2: filter B-filter A-sedimentation tank-filter C mode operation:

[0072] (1) Filter B is always kept in a water-filled state;

[0073] (2) The first stage: Filter B is kept inflowing but not outflowing to perform preliminary treatment of domestic sewage. At the same time, filter A is backwashed. The backwash effluent is precipitated in sedimentation tank D and further treated in filter C:

[0074] (3) The second stage: After the backwashing of filter A is completed, filter B performs preliminary treatment on domestic sewage, and the effluent of filter B is further treated in filter A. The effluent of filter A is then precipitated in sedimentation tank D and deeply treated in filter C.

[0075] (4) The above is the processing operation process under one mode. Then reselect a mode and repeat the above steps (1)-(3). By switching operations under different modes, the richness of microorganisms in different filter pools is guaranteed to be the same, further ensuring the processing efficiency of the filter pool.

[0076] Example 4:

[0077] The parts that are the same as those in Example 2 will not be described in detail in this example.

[0078] First select mode three: filter C - filter B - sedimentation tank - filter A mode operation:

[0079] (1) Filter C is always kept in a water-filled state;

[0080] (2) The first stage: Filter C only takes in water but does not discharge water to perform preliminary treatment of domestic sewage. At the same time, filter B performs backwashing. The backwash effluent is precipitated in sedimentation tank D and deeply treated in filter A.

[0081] (3) The second stage: After the backwashing of filter B is completed, filter C performs preliminary treatment on domestic sewage, and the effluent of filter C is further treated by filter B. The effluent of filter B is then precipitated in sedimentation tank D and deeply treated by filter A.

[0082] (4) The above is the processing operation process under one mode. Then reselect a mode and repeat the above steps (1)-(3). By switching operations under different modes, the richness of microorganisms in different filter pools is guaranteed to be the same, further ensuring the processing efficiency of the filter pool.

[0083] The modes of the above-mentioned embodiments 2-4 are not exhaustive.

Claims

1. An alternating multi-stage aeration biological filter device for treating domestic sewage, characterized in that: The device includes a functional area and an external structure of the functional area; the functional area includes mutually independent filter tanks A, B, C and a sedimentation tank, wherein filter tanks A, B and C are each provided with an upper filler layer, a branch pipe of a middle aeration pipe, a lower filler layer, a support layer and filter bricks in order from top to bottom; the external structure of the functional area includes an inlet pipe, a sedimentation outlet pipe, a sedimentation inlet pipe, a vent pipe, a main pipe of the middle aeration pipe, a water distribution and air distribution box, a filter tank connecting pipe serving as a backwash inlet pipe, a backwash inlet pipe and a clarified water outlet pipe; The water inlet pipe is connected to the filter A, filter B and filter C respectively; The sedimentation tank is provided with a sedimentation outlet pipe and a sedimentation inlet pipe, and the sedimentation outlet pipe and the sedimentation inlet pipe are respectively connected to the filter tank A, the filter tank B and the filter tank C; The vent pipe is connected to the filter A, filter B, filter C and the sedimentation tank respectively; The water and air distribution boxes are installed on the outside of the filter tanks A, B and C. The water and air distribution boxes are used to evenly distribute the backwash water and air to the filter bricks during backwashing. Secondly, when clarifying the water, the water distribution boxes are used to merge the water collected by the filter bricks and then discharge it. The water and air distribution boxes of the filter tanks A, B and C are connected to each other through the filter tank connecting pipe which also serves as the backwash water inlet pipe. The backwash air inlet pipe and the clarified water outlet pipe are communicated with the water and air distribution boxes of the filter tank A, the filter tank B and the filter tank C respectively.

2. The alternating multi-stage biological aeration filter device for treating domestic sewage according to claim 1, characterized in that: The supporting layer is made of crushed stone; the lower packing layer and the upper packing layer are made of particles with excellent phosphorus removal function; the filter bricks are used to evenly distribute the backwash water and air to the supporting layer, the lower packing layer and the upper packing layer, and to collect the clarified water.

3. The alternating multi-stage biological aeration filter device for treating domestic sewage according to claim 1, characterized in that: A radial flow pipe is erected in the center of the sedimentation tank, and a sedimentation outlet weir is arranged on the upper part of the sedimentation tank.

4. The alternating multi-stage biological aeration filter device for treating domestic sewage according to claim 1, characterized in that: The filter tank A, filter tank B, filter tank C and sedimentation tank in the functional area are arranged in a straight line or in a field shape, and can be arranged according to the terrain.

5. A method for treating domestic sewage in an alternating multi-stage manner using the alternating multi-stage biological aeration filter device for treating domestic sewage according to any one of claims 1 to 4, characterized in that: The method comprises: (1) Select any filter tank and continue to feed water; (2) The first stage: The filter tank only takes in water but does not discharge water to perform preliminary treatment of domestic sewage, while the other filter tank performs backwashing. The backwash effluent is precipitated in the sedimentation tank and then deeply treated in the third filter tank; (3) Second stage: After the backwashing of the backwashing filter is completed, the filter holding water inlet performs preliminary treatment on the domestic sewage, and the effluent of the filter holding water inlet is further treated by the backwashing filter. The effluent after further treatment is then precipitated in the sedimentation tank and subjected to deep treatment in the third filter; (4) Reselect different filter tanks to alternately inlet water, and repeat steps (1) to (3) to maintain high biological abundance in the filter tanks and improve the removal rate of pollutants in low carbon-nitrogen ratio domestic sewage.

6. The method according to claim 5, wherein The first stage: When water is selected to enter any filter, the water in the filter flows from top to bottom, passing through the aerobic treatment of the upper filler layer, the anoxic treatment of the lower filler layer, the support layer and the filter bricks in sequence. The middle aeration pipe continuously provides oxygen to the upper filler layer, and the filter performs preliminary treatment on the pollutants in the sewage. When the filter tank is filled with water, the other filter tank is backwashed in an air-water backwashing mode; the backwashing water flows from the sedimentation inlet pipe into the radial flow pipe of the sedimentation tank for static sedimentation, and the sedimentation water overflows to the sedimentation outlet weir and flows into the third filter tank from the sedimentation outlet pipe; The water in the third filter tank flows from top to bottom, passing through the aerobic treatment of the upper filler layer, the anoxic treatment of the lower filler layer, the supporting layer and the filter bricks in turn. The middle aeration pipe continuously provides oxygen to the upper filler layer. At this time, the sewage undergoes an aerobic and anoxic process, and the pollutants in the sewage are deeply treated. The sewage after deep treatment meets the discharge requirements and is discharged from the clarification outlet pipe nearby.

7. The method according to claim 5 or 6, wherein: The second stage: after the backwashing of the backwashing filter is completed, the effluent of the filter holding the water inlet is collected through its filter bricks and enters the water distribution and air distribution box of the backwashing filter through the filter connecting pipe which also serves as the backwashing water inlet pipe. The effluent is then evenly distributed from the filter bricks of the backwashing filter to the supporting layer, the lower packing layer and the upper packing layer from bottom to top. The middle aeration pipe continuously provides oxygen to the upper packing layer to further treat the pollutants in the sewage. The effluent after further treatment enters the radial flow pipe of the sedimentation tank from the sedimentation inlet pipe for static sedimentation, and the sedimentation effluent overflows to the sedimentation effluent weir and flows into the third filter tank from the sedimentation effluent pipe; The water in the third filter tank flows from top to bottom, passing through the aerobic treatment of the upper filler layer, the anoxic treatment of the lower filler layer, the supporting layer and the filter bricks in turn. The middle aeration pipe continuously provides oxygen to the upper filler layer to deeply treat the pollutants in the sewage. The sewage after deep treatment meets the discharge requirements and is discharged from the clarification outlet pipe nearby.

8. The method according to claim 5 or 6, wherein: When the amount of sludge in the sedimentation tank reaches a high level, a sludge pump is used to pump it out for external disposal; When the device needs to be moved to another location for operation, the water in the functional area is drained from the drain pipe and the device can be transported by vehicle.

Images