Multifunctional modular wetland pilot test device for nitrogen and phosphorus removal

Abstract

The present invention relates to a multifunctional modular wetland pilot test device for denitrification and phosphorus removal. The present invention is applicable to the technical field of artificial wetlands. The technical solution adopted by the present invention is: a multifunctional modular wetland pilot test device for denitrification and phosphorus removal, characterized in that: it has a device body, an inlet pipe system and an outlet pipe system; the device body includes a main frame and a water outlet layer arranged at the bottom of the main frame, and a plurality of module filling grids arranged in the main frame and above the water outlet layer, and the module filling grids are filled with fillers; the inlet pipe system includes an inlet branch pipe connected to one end of each column of module filling grids and is equipped with a gate valve for controlling the on-off of the inlet branch pipe, and the outlet pipe system includes an outlet branch pipe connected to the other end of each column of module filling grids and is equipped with a gate valve for controlling the on-off of the outlet branch pipe.

Description

Technical Field

[0001] The invention relates to a multifunctional modular wetland pilot test device for nitrogen removal and phosphorus removal, which is applicable to the technical field of artificial wetlands. Background Art

[0002] Artificial wetlands are an environmentally friendly sewage treatment method. Artificial wetlands use the synergistic effects of substrates, plants, and microorganisms to purify sewage through adsorption, precipitation, degradation, and absorption. As an ecological technology for reducing water pollutants, artificial wetlands use a combination of structural processes and water distribution methods to simulate the microenvironment of material metabolism in nature, intercepting, adsorbing, and degrading pollutants such as nitrogen, phosphorus, and organic matter under the coupling of plants, substrates, and microorganisms, effectively improving the water environment. It has the characteristics of simple structure, low operation and maintenance costs, and good effluent quality. It has been widely used in treating surface runoff, industrial wastewater, domestic sewage, livestock and poultry breeding wastewater, sewage plant tailwater, and drinking raw water.

[0003] At present, a lot of research has been carried out on typical problems in the operation process of artificial wetlands to build an integrated technology system for deep reduction of nitrogen and phosphorus in artificial wetlands, such as: 1) research on the improvement of biomass and inorganic fillers; 2) research on weak electric energy enhanced biological denitrification technology; 3) research on electrochemical oxidation-reduction flocculation denitrification and phosphorus removal technology; 4) research on the process of biological denitrification in artificial wetlands enhanced by compliant fillers; 5) characteristics of horizontal and vertical subsurface artificial wetlands, etc. For the above research, it is necessary to set up equipment to carry out experiments. However, when conducting research on different contents, it is necessary to redesign the test platform of the artificial wetland, which consumes manpower and material resources, and the original test equipment is discarded after the experiment, resulting in a waste of resources. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the above-mentioned problems, a multifunctional modular wetland pilot test device for nitrogen and phosphorus removal is provided.

[0005] The technical solution adopted by the present invention is: a multifunctional modular wetland pilot test device for nitrogen and phosphorus removal, characterized by: a device body, a water inlet pipeline system and a water outlet pipeline system;

[0006] The device body comprises a main frame and a water outlet layer arranged at the bottom of the main frame, and a plurality of module filling grids arranged in the main frame and above the water outlet layer, wherein the module filling grids are filled with fillers;

[0007] The main frame and the water outlet layer are divided into L layers in height, and each layer is separated by row-wise fixed partitions and column-wise fixed partitions to form M*N grids of module filling grids, and the bottom of the module filling grid is provided with a grid bottom plate and a detachable solid bottom plate;

[0008] The water inlet pipe system includes a water inlet branch pipe connected to one end of each row of module packing grids and equipped with a gate valve for controlling the on-off of the water inlet branch pipe, and the water outlet pipe system includes a water outlet branch pipe connected to the other end of each row of module packing grids and equipped with a gate valve for controlling the on-off of the water outlet branch pipe;

[0009] The water inlet pipeline system also includes a drip branch pipe arranged on the top of the device body, and the water outlet pipeline system also includes a bottom water outlet pipe connected to the water outlet layer and equipped with a gate valve for controlling the opening and closing of the bottom water outlet pipe;

[0010] A flow gap I is left between the top of the row-oriented fixed partition and the bottom plate of the upper layer of module filling grid; a sliding partition parallel to the row-oriented fixed partition and capable of sliding up and down is provided in the module filling grid near the outlet branch pipe, and a flow gap II is left between the sliding partition and the row-oriented fixed partition on this side.

[0011] The test device also has an electrode circuit system, which includes positive and negative electrodes respectively arranged on the water inlet branch pipe side and the water outlet branch pipe side of the module filler grid.

[0012] A water inlet main pipe is provided corresponding to each layer of the module filling grid, and the water inlet main pipe is connected to all the water inlet branches of the layer. The water inlet main pipe is provided with a gate valve for controlling the on-off of the water inlet branch pipes.

[0013] A water outlet main pipe is provided corresponding to each layer of the module filling grid, and the water outlet main pipe is connected to all the water outlet branches of the layer. The water outlet main pipe is provided with a gate valve for controlling the on-off of the water outlet branch pipes.

[0014] A test method of the test device is characterized in that when the artificial wetland adopts horizontal flow conditions:

[0015] The drip branch pipe and the bottom water outlet pipe are closed by the corresponding gate valves, the water inlet branch pipe and the water outlet branch pipe are connected, and the sliding partition in each module filler grid is slid down to form a flow hole under the sliding partition. The flow hole and the corresponding flow gap II and flow gap I cooperate to form a flow channel connecting the bottom of the module filler grid and the top of the next module filler grid in the water flow direction.

[0016] A test method of the test device is characterized in that when the artificial wetland adopts a vertical flow condition:

[0017] Shut off the water inlet and outlet branches through the corresponding gate valves, connect the drip branch and the bottom outlet pipe, slide the sliding partition in each module filler grid down to fit the bottom of the module filler grid, and remove the solid bottom plate at the bottom of the module filler grid.

[0018] The beneficial effects of the present invention are as follows: the present invention realizes the switching of the structure, filler and operating conditions of the artificial wetland by controlling the on-off of the water inlet pipe system and the water outlet pipe system, coordinating the operation of the sliding partition and the solid bottom plate and the adjustment of the filler, so as to achieve the purpose of carrying out different research contents. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the device body in the embodiment.

[0020] Figure 2 Schematic diagram of the plan view of the device body in the embodiment.

[0021] Figure 3 Schematic diagram of the structure of the water inlet pipeline system in the embodiment.

[0022] Figure 4 Schematic diagram of the structure of the water outlet pipeline system in the embodiment.

[0023] Figure 5 Schematic diagram of the arrangement of the electrode circuit system in the embodiment.

[0024] Figure 6 It is a three-dimensional diagram of the module filling grid in the embodiment.

[0025] Figure 7 Schematic diagram of parallel electrode circuit connection in the embodiment.

[0026] Figure 8 Schematic diagram of horizontal flow condition of artificial wetland in the embodiment.

[0027] Fig. 9 Schematic diagram of vertical flow condition of artificial wetland in the embodiment.

[0028] Fig.10 Schematic diagram of the electrochemical redox coupled electro-flocculation working condition in the embodiment.

[0029] Fig.11 It is a schematic diagram of the working conditions of weak electric energy biological denitrification and phosphorus removal in the embodiment.

[0030] 1. Device body; 1-1. Module filling grid; 1-2. Fixed partition in row direction; 1-3. Fixed partition in column direction; 1-4. Grid bottom plate; 1-5. Solid bottom plate; 1-6. Sliding partition; 1-7. Flow gap I; 1-8. Flow gap II; 1-9. Flow hole; 1-10. Water outlet layer; 2. Water inlet branch pipe; 3. Water inlet main pipe; 4. Drip branch pipe; 5. Water outlet branch pipe; 6. Water outlet main pipe; 7. Bottom water outlet pipe; 8. Positive electrode; 9. Negative electrode. DETAILED DESCRIPTION

[0031] The present embodiment is a multifunctional modular wetland pilot test device for nitrogen and phosphorus removal, which comprises a rectangular device body, a water inlet pipe system, a water outlet pipe system and an electrode circuit system.

[0032] In this example, the main body of the device includes a main frame (a hollow rectangular steel support), a water outlet layer is provided at the bottom of the main frame (the limited water storage depth is about 30~50cm), and a number of module filling grids are provided in the main frame and the water outlet layer, and the module filling grids are filled with fillers.

[0033] In this embodiment, the main frame and the water outlet layer are divided into three layers in height, and each layer is separated by two row-direction fixed baffles (parallel to the width direction of the main frame) and two column-direction fixed baffles (parallel to the length direction of the main frame) to form a module packing grid with three rows and three columns, which is a nine-square grid structure. The bottom plate of the module packing grid is a grid bottom plate, and a detachable solid bottom plate is provided under the grid bottom plate, wherein the mesh of the grid bottom plate is smaller than the particle size of the packing.

[0034] In this example, the water inlet pipe system includes a water inlet branch pipe connected to one end of each row of module filling grids, the water inlet branch pipes on each layer are connected to a water inlet main pipe, and a gate valve is set at the starting end of the water inlet main pipe; the water outlet pipe system includes a water outlet branch pipe connected to the other end of each row of module filling grids, the water outlet branch pipes on each layer are connected to a water outlet main pipe, and a gate valve is set at the end of the water outlet main pipe.

[0035] In this embodiment, the water inlet pipeline system also includes a drip branch pipe arranged on the top of the device body, and the water outlet pipeline system also includes a bottom water outlet pipe connected to the water outlet layer and equipped with a gate valve for controlling the opening and closing of the bottom water outlet pipe.

[0036] In this embodiment, a certain flow gap I is left between the top of the row fixed partition and the bottom plate of the upper layer of the module packing grid. A sliding partition parallel to the row fixed partition and capable of sliding up and down is provided near the outlet branch pipe in each module packing grid, and a flow gap II is left between the sliding partition and the row fixed partition on that side. When the sliding partition slides down, a flow hole can be formed between the bottom of the sliding partition and the bottom plate of the module packing grid.

[0037] In this embodiment, the electrode circuit system is mainly composed of positive and negative electrodes, a resistor, a circuit and a DC power supply, wherein the positive and negative electrodes are respectively arranged on the water inlet branch pipe side and the water outlet branch pipe side of the modular filling grid, and the electrode circuit system between each modular filling slot is connected in parallel.

[0038] In this example, the different biomass and inorganic fillers in the module filler grid can be composed of biochar, ceramsite, limestone, pyrite, volcanic rock, zeolite, pyrite, gravel, etc.

[0039] The method for conducting the test using the multifunctional modular wetland pilot test device for nitrogen and phosphorus removal in this embodiment includes:

[0040] When the artificial wetland adopts horizontal flow conditions, the valves of the drip branch pipe on the top of the device body and the outlet pipe at the bottom are all closed, and the water from the water inlet main pipe enters the water inlet main pipe of each layer, and then flows into the module filler grid through the water inlet branch pipe, and slides the sliding partition in each module filler grid upward so that the sliding partition is about 2~3cm away from the bottom, forming a flow hole, and the flow hole and the corresponding flow gap II and flow gap I cooperate to form a flow channel connecting the bottom of the module filler grid and the top of the next module filler grid in the water flow direction. The water flow of each layer first enters the module filler grid from the water inlet branch pipe. Under the filtering effect of the first grid filler, the water flows from the flow channel to the next module filler grid. Similarly, the water flows through the second and third grid fillers in turn, and finally flows out from the outlet branch pipe. Finally, the water flows to the nearest drainage system.

[0041] When the horizontal flow of the artificial wetland is subjected to different hydraulic retention time comparison test conditions, the gate valves of the drip branch pipes on the top of the device body are all closed, and the gate valves on the upper, middle and lower layers are adjusted to different opening and closing degrees to achieve different water inflows, thereby achieving different hydraulic retention times for each layer. The total nitrogen concentrations of the inlet and outlet water are collected as C1 and C0, respectively, and the denitrification rate is calculated The total phosphorus concentrations of the inlet and outlet water are B1 and B0 respectively, and the phosphorus removal rate , and thus the optimal hydraulic retention time when the nitrogen removal rate and phosphorus removal rate are the highest can be obtained through experiments.

[0042] When the horizontal flow of the artificial wetland is tested under comparative test conditions using different fillers, the gate valves of the drip branch pipes on the top of the device body are all closed, one gate valve is opened in any one of the upper, middle and lower layers, and the gates of the other two layers are closed. The three rows of module filler grids in the same layer are filled with unused filter media to analyze and obtain the best filter media combination to achieve the best nitrogen and phosphorus removal effect under the same hydraulic retention time.

[0043] When the artificial wetland adopts vertical flow conditions, the gate valves of each layer of water inlet and outlet main pipes are all closed, and the water flows along the water inlet main pipe into the drip branch pipe at the top of the device body, and the water flows out from the drip hole in the drip branch pipe. The sliding partition in each module packing grid fits with the bottom to ensure that the water in the tank will not overflow in the horizontal direction. The bottom solid bottom plate in the module packing grid is removed, leaving only the grid bottom plate, and the mesh of the grid bottom plate is smaller than the particle size of the packing. The water in the drip branch pipe is filtered from the top layer of filter material and enters the middle layer and the bottom layer in turn, and finally flows out from the bottom outlet pipe.

[0044] When conducting a comparative test of different hydraulic retention times in vertical flow, the gate valves of the upper, middle and lower layers are all closed, and the gate valves of the drip branch pipe at the top of the rectangular device are opened at different opening and closing degrees to achieve different inlet flow rates, and then achieve different hydraulic retention times for each column in the vertical direction. The total nitrogen concentrations C1 and C0 of the inlet and outlet water quality are collected, and the denitrification rate is calculated. The total phosphorus concentrations of the inlet and outlet water are B0 and B1 respectively, and the phosphorus removal rate Through experiments, the optimal hydraulic retention time T when the denitrification rate is the highest is obtained.

[0045] When the vertical flow of the artificial wetland is subjected to the comparative test conditions with different fillers, the gate valves of the upper, middle and lower layers in the vertical direction are all closed, and the gate valves of the three drip branch pipes at the top of the rectangular device are all opened. The three columns of module filler grids in the vertical direction are filled with different fillers according to the experimental needs for comparative tests. Similarly, the total nitrogen concentrations C1 and C0 of the inlet and outlet water and the inlet and outlet water concentrations of total phosphorus are detected respectively, and the denitrification rate is calculated. The total phosphorus concentrations of the inlet and outlet water are B0 and B1 respectively, and the phosphorus removal rate Through experiments, the filler ratio when the denitrification rate and dephosphorization rate are the highest is obtained.

[0046] When the artificial wetland adopts weak electric energy to enhance the biological denitrification and phosphorus removal conditions, limestone, biochar and quartz sand filter materials are filled into the first, second and third module filler grids respectively along the direction of water flow, and the electrode circuit installed in the module filler grid is connected to the power supply to obtain the current density i (mA / m3) = current size I (mA) / filler volume V (m3). The size of the rheostat is adjusted so that the current density in each module filler grid is different, and the current density gradually increases with the direction of water flow.

[0047] When the constructed wetland adopts electrochemical redox coupled electroflocculation, along the water flow direction, the first cell of the module filler grid is filled with biochar and ceramsite, the second cell near the anode is filled with limestone and pyrite mixed in a ratio of 1:1 (10 cm), and the cathode is filled with magnetite (10 cm); the third cell is filled with ordinary gravel. Oxidation reaction occurs on the anode side of the electrode, and the reaction equations are shown in (1) to (5).

[0048]

[0049] A reduction reaction occurs on the cathode side of the electrode, and the reaction equations are shown in (6) to (8).

[0050]

[0051] By adjusting the current, the denitrification rate and dephosphorization rate under different current density conditions are compared to obtain the optimal current density value.

[0052] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of this patent are covered by the protection scope of this patent.

Claims

1. A multifunctional modular wetland pilot test device for nitrogen and phosphorus removal, characterized by: It has a device body, a water inlet pipe system and a water outlet pipe system; The device body comprises a main frame and a water outlet layer arranged at the bottom of the main frame, and a plurality of module filling grids arranged in the main frame and above the water outlet layer, wherein the module filling grids are filled with fillers; The main frame and the water outlet layer are divided into L layers in height, and each layer is separated by row-wise fixed partitions and column-wise fixed partitions to form M*N grids of module filling grids, and the bottom of the module filling grid is provided with a grid bottom plate and a detachable solid bottom plate; The water inlet pipe system includes a water inlet branch pipe connected to one end of each row of module packing grids and equipped with a gate valve for controlling the on-off of the water inlet branch pipe, and the water outlet pipe system includes a water outlet branch pipe connected to the other end of each row of module packing grids and equipped with a gate valve for controlling the on-off of the water outlet branch pipe; The water inlet pipeline system also includes a drip branch pipe arranged on the top of the device body, and the water outlet pipeline system also includes a bottom water outlet pipe connected to the water outlet layer and equipped with a gate valve for controlling the opening and closing of the bottom water outlet pipe; A flow gap I is left between the top of the row-direction fixed partition and the bottom plate of the upper layer of the module packing grid; a sliding partition parallel to the row-direction fixed partition and capable of sliding up and down is provided in the module packing grid near the outlet branch pipe, and a flow gap II is left between the sliding partition and the row-direction fixed partition on this side; A water inlet main pipe is provided corresponding to each layer of the module packing grid, and the water inlet main pipe is connected to all the water inlet branches of the layer, and the gate valve for controlling the on-off of the water inlet branch pipe is provided on the water inlet main pipe; A water outlet main pipe is provided corresponding to each layer of the module filling grid, and the water outlet main pipe is connected to all the water outlet branches of the layer. The water outlet main pipe is provided with a gate valve for controlling the on-off of the water outlet branch pipes.

2. The multifunctional modular wetland pilot test device for nitrogen and phosphorus removal according to claim 1 is characterized in that: The test device also has an electrode circuit system, which includes positive and negative electrodes respectively arranged on the water inlet branch pipe side and the water outlet branch pipe side of the module filler grid.

3. A test method for the test device according to any one of claims 1 to 2, characterized in that: When the artificial wetland adopts horizontal flow conditions: The drip branch pipe and the bottom water outlet pipe are closed by the corresponding gate valves, the water inlet branch pipe and the water outlet branch pipe are connected, and the sliding partition in each module filler grid is slid down to form a flow hole under the sliding partition. The flow hole and the corresponding flow gap II and flow gap I cooperate to form a flow channel connecting the bottom of the module filler grid and the top of the next module filler grid in the water flow direction.

4. A test method for the test device according to any one of claims 1 to 2, characterized in that: When the constructed wetland adopts vertical flow conditions: Shut off the water inlet and outlet branches through the corresponding gate valves, connect the drip branch and the bottom outlet pipe, slide the sliding partition in each module filler grid down to fit the bottom of the module filler grid, and remove the solid bottom plate at the bottom of the module filler grid.

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