Device for recovering phosphorus in sewage pipe network and method for realizing blue iron stone in-situ enrichment and recovery

Abstract

The invention discloses a device for recovering phosphorus in a sewage pipe network and a method for realizing in-situ enrichment and recovery of blue iron stone. A capture device is arranged at the joint of the sewage pipe network, an electromagnetic valve is arranged above the flange, a filter membrane is arranged below the flange, a reaction bed is arranged in the capture device and is of a multi-layer structure, a carbon-based material is arranged in the reaction bed of the capture device, iron ore is laid on the carbon-based material to serve as a supplementary iron source, and the filter membrane is arranged in the filter membrane. According to the flow velocity of sewage, a capturer is arranged at each interval, a communicating valve is arranged at the bottom of each capturer, a speed sensor is arranged at the bottom of each communicating valve, each capturer is communicated through a connecting pipeline by the communicating valves, and a pressure sensor is arranged on the connecting pipeline. When the pressure value of the sensor exceeds 50% of the initial value, the electromagnetic valve and the communication valve are closed; or the velocity sensor displays that the flow velocity is reduced by 40% compared with the initial value, and the solenoid valve and the communication valve are closed. The blue iron stone recycling device achieves efficient recycling of blue iron stone.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochemical treatment of sewage and its resource utilization, and specifically relates to a device for recovering phosphorus in a sewage pipe network and a method for realizing in-situ enrichment and recovery of blue iron stone. The invention is designed to install a sinking capture device connected by a flange in an urban sewage pipe network system to realize in-situ recovery of sewage phosphorus as a high-value-added product blue iron stone. Background Art

[0002] The stable and efficient operation of the urban sewage treatment system affects the treatment effect of the downstream sewage treatment plant and is closely related to the environmental sanitation of urban development. In recent years, the urban sewage pipe network has gradually attracted widespread attention as a "biochemical reactor" or sewage treatment facility. During the transportation of urban domestic sewage in the pipe network, a large number of highly active microorganisms will be enriched and attached to the inner wall of the pipe network. The microorganisms promote their own growth and metabolism by utilizing organic matter and nutrients such as nitrogen and phosphorus in the sewage, which directly affects the influent water quality of the subsequent sewage treatment plant. Microorganisms with dissimilatory reduction function can make full use of the excess phosphorus in the sewage to form a high-value-added iron-phosphorus product, blue iron. In recent years, the phosphorus recovery technology of microbial dissimilatory iron reduction to synthesize blue iron has received widespread attention in domestic sewage treatment. Dissimilatory iron-reducing microorganisms use organic matter in sewage to metabolize substrates to generate energy while releasing electrons to the iron ore receptors in the form of trivalent iron outside the cell. After receiving electrons, the iron ore is reduced to divalent iron. When the concentration reaches the threshold, it combines with sufficient phosphate ions in the sewage to form a relatively stable blue iron. The rich organic matter and phosphates in domestic sewage and the anaerobic environment formed by the closed sewage pipe network provide suitable conditions for the formation of blue iron stone.

[0003] In addition, during the sewage transportation process, blue iron particles form a sedimentation effect in the pipe network and gather inside the pipe network. This phenomenon causes the blockage of the sewage pipe network and increases the maintenance cost to a certain extent. Therefore, a sinking blue iron capturer connected by a flange is set at the pipe network interface, which is conducive to the timely recovery of blue iron and alleviates the blockage and maintenance problems of the pipe network, and at the same time realizes the recovery of phosphorus in sewage. Therefore, when the sewage flows through the interface, a part of the sewage sinks to the capturer due to gravity, and the in-situ enrichment and recovery of blue iron can be achieved in this micro-biochemical reactor. In addition, the microbial-driven dissimilatory iron reduction process can enhance the extracellular electron transfer by exogenously adding low-cost and highly selective conductive carbon-based materials, thereby improving the recovery efficiency of blue iron and promoting the resource circulation of phosphorus. However, the judgment of the enrichment and recovery degree lacks the support of experimental data, and is often judged by experience. The corresponding iron ore supply and carbon-based material addition amount have long lacked experimental data.

[0004] Therefore, the present invention designs a new type of pipe network blue iron stone capture device which is installed at the interface of the sewage pipe network and utilizes local alienation-reduction microorganisms to recover the high-value product blue iron stone, thereby realizing the resource application of sewage. This is of great significance to the efficient and healthy operation of the urban sewage pipe network system. Summary of the invention

[0005] The present invention aims to propose a blue iron stone capture device installed at the interface of the sewage pipe network to realize in-situ phosphorus recovery. The capture device selects iron ore with high environmental abundance as a supplementary iron source and low-cost and high-selectivity carbon-based materials as enhanced functional fillers, which can realize in-situ high-value recovery of phosphorus in the sewage pipe network while solving the problems of pipe network system blockage and maintenance and the phosphorus removal pressure of subsequent sewage treatment process sections.

[0006] To achieve the above object, the present invention provides the following technical solutions: a device for recovering phosphorus in a sewage pipe network, connected to the sewage pipe network, a catcher is arranged at the interface of the sewage pipe network, the catcher and the sewage pipe network are connected by a flange, a solenoid valve is installed above the flange, a filter membrane is arranged below the flange, a reaction bed is arranged in the catcher, the reaction bed is a multi-layer structure, each layer is arranged as a grid structure, and the distance between each adjacent layer is 1 / 3-1 / 5 of the height of the reaction bed;

[0007] A carbon-based material is provided in the capture device reaction bed, and iron ore is laid on the carbon-based material as a supplementary iron source, and the molar ratio of the carbon-based material to the iron ore is 1-1.7:1;

[0008] A trap is arranged at each interval according to the sewage flow rate, a connecting valve is arranged at the bottom of each trap, a speed sensor is arranged at the bottom of the connecting valve, the connecting valve connects each trap through a connecting pipe, and a pressure sensor is arranged on the connecting pipe.

[0009] The grid is arranged as a square grid or a diamond grid according to the morphological characteristics of the iron ore and the carbon-based material.

[0010] An annular sealing gasket is installed at the connection between the flange and the catcher, and the flange material is consistent with the pipeline material.

[0011] The filter membrane is used for intercepting and filtering impurities in sewage, and at the same time preventing the filler and the product blue iron stone in the collector from being washed out by the water flow. The pore size of the filter membrane is in the micron level.

[0012] The iron ore is selected from lepidocrocite, ferrihydrite or hematite.

[0013] The carbon-based material is selected from biochar, graphite or carbon black.

[0014] The second technical solution of the present invention is a method for realizing in-situ enrichment and recovery of blue iron stone by a phosphorus recovery device in a sewage pipe network, comprising the following steps:

[0015] S1: Before installing the capture device, add carbon-based materials into the reaction bed, lay iron ore at the bottom of the reaction bed as a supplementary iron source, and the molar ratio of carbon-based materials to iron ore is 1-1.7:1;

[0016] S2: Install the trap at the pipe network interface with flange connection. According to the designed flow rate of sewage pipe 1-1.5m / s, set a trap at every 0.5-1m interval in the pipe network; when the flow rate is <1m / s, the interval between the traps is controlled to be 1-2m; when the flow rate is greater than 1.5m / s, the interval between pipes is controlled to be 0.3-0.5m;

[0017] S3: Open the solenoid valve and the connecting valve to connect the capture devices to achieve the flow of liquid medium;

[0018] S4: Observe the pressure change of the pressure sensor and the speed sensor to determine whether the enrichment of the trap is completed;

[0019] S5: When the sensor pressure value exceeds the initial value by 50%, the solenoid valve and the connecting valve are closed;

[0020] The velocity sensor shows that the flow rate is 40% lower than the initial value, and the solenoid valve and the connecting valve are closed;

[0021] S6: The collector is disassembled through the flange, and the contents in the reaction bed are centrifuged and dried to obtain the high value-added product blue iron stone.

[0022] Further, the molar ratio of the carbon-based material to the iron ore is 1.1:1;

[0023] Further, the molar ratio of the carbon-based material to the iron ore is 1.3:1;

[0024] The present invention has the following advantages:

[0025] The present invention creatively proposes a structural device for setting an in-situ blue iron stone catcher at the pipe network interface, and its beneficial effects are specifically embodied in:

[0026] (1) The trap can be installed at the interfaces of various pipes in the sewage and wastewater network. By utilizing the high abundance of heterotrophic iron-reducing microorganisms in the sewage and wastewater and the sufficient organic matter and phosphorus sources in the background, the high-value-added iron-phosphorus product blue iron can be recovered in situ during pipeline maintenance, thus realizing high-value sewage recovery and cost reduction and efficiency improvement in various scenarios such as urban sewage networks and sewage treatment plants.

[0027] (2) The base filler of the collector is green, high-performance carbon-based materials and iron ore particles. On the one hand, the iron ore particles serve as a supplementary iron source to ensure the full conversion of phosphorus in the wastewater. On the other hand, the low-cost and highly selective carbon-based materials can promote the enrichment and growth of microorganisms and improve the efficiency of electron transfer due to their rich functional groups and good conductivity, thereby achieving efficient recovery of blue iron ore in wastewater in various scenarios such as official website.

[0028] (3) The trap can intercept phosphorus in sewage in advance, which reduces the phosphorus removal pressure of downstream sewage treatment plants in the urban sewage discharge system and reduces the dosage of iron flocculants compared to traditional phosphorus treatment processes.

[0029] (3) A multi-layer grid structure is provided in the capture reactor, and the distance between each layer is 1 / 3-1 / 5 of the height of the reaction bed. The carbon-based material and the supplementary iron source can be fully released, which is beneficial to the formation of blue iron stone.

[0030] (4) A connecting valve is provided at the bottom of the capturer. Through the connection, the fluidity between the capturers at the bottom of the pipeline is increased during the phosphorus recovery in the sewage network and the in-situ enrichment and recovery of blue iron ore, which can fully enrich and improve the recovery rate. In addition, the bottom connecting pipeline is equipped with a pressure sensor and a speed sensor to sense the changes in pressure and flow rate, and the degree of enrichment and recovery can be judged. Furthermore, the opening and closing of the solenoid valve and the bottom connecting valve can be remotely controlled to timely dismantle and replace the new device.

[0031] (5) The trap effectively controls pipeline corrosion. The blue iron stone recovered in situ is collected in the trap, which effectively prevents pipeline blockage, extends the service life of sewage pipelines and reduces pipeline maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the installation of the capture device in the sewage network.

[0033] Figure 2 This is a schematic diagram of the capture device structure. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with examples, but the embodiments of the present invention include but are not limited to these.

[0035] The present invention is based on the dissimilatory iron reduction process driven by microorganisms in the anaerobic environment of the sewage pipe network, and efficiently recovers phosphorus in the form of high value-added product blue iron stone. The characteristic is that the blue iron stone trap is installed at the pipe network interface by flange fixing and filter membrane interception by utilizing the anaerobic environment and hydraulic sinking of the sewage pipe network, the reaction bed in the trap is supplemented with iron ore as a supplementary iron source, and the carbon-based material is used as a carrier for microbial enrichment and enhanced electron transfer. The further definition scheme of the structural design of each part is as follows:

[0036] In the above-mentioned capture device installation design, the number and location of the capture devices are determined according to the laying density of the sewage pipe network and the flow rate of the sewage along the pipe network.

[0037] In the above-mentioned trap installation design, an annular sealing gasket is installed at the connection between the flange and the trap, and four threaded holes are evenly opened on the outside of the flange. The flange material is consistent with the pipeline material, and its function is to ensure the full connection between the trap and the pipeline.

[0038] In the above-mentioned installation design of the trap, a filter membrane is installed under the flange to intercept and filter impurities in the sewage, while preventing the filler and product blue iron stone in the trap from being washed out by the water flow. The pore size of the filter membrane is preferably in the μm level.

[0039] In the above-mentioned capture device installation design, iron ore and carbon-based materials are added into the reaction bed before the capture device is installed, and a square or diamond reaction bed structure can be set in each capture device according to the morphological characteristics of the iron ore and carbon-based materials.

[0040] In the above-mentioned capture installation design, iron ore particles are laid in the capture reaction bed as a supplementary iron source for microbial alienation of iron reduction and recovery of blue iron ore. Iron ore particles with high surface energy, low crystallinity and large specific surface area are preferably selected according to local geological conditions and the abundance and type of iron oxides in the urban drainage system.

[0041] In the above-mentioned capture installation design, carbon-based materials are laid in the capture reaction bed as microbial enrichment carriers and functional fillers to enhance the microbial extracellular electron transfer to synthesize blue iron stone. Low-cost carbon-based materials with rich functional groups and good conductivity are preferably selected according to different scenarios and local conditions.

[0042] In the above-mentioned capture installation design, the blue iron stone in the capture can be regularly collected and recycled according to the inspection and maintenance cycle of the sewage network. The capture can be disassembled through the flange, and the contents in the reaction bed are centrifuged and dried to obtain the high value-added product blue iron stone.

[0043] Embodiment 1:

[0044] Before installing the trap, Fe2O3 particles and graphite are added. The molar ratio of carbon-based materials to iron ore is 1:1. The filter membrane is installed at the interface of the trap and fixed with a flange containing a ring seal. The sewage from the main pipeline flows through here and flows into the trap due to gravity. At this time, under the action of the alienated iron-reducing microorganisms in the sewage, the Fe2O3 in the filler is reduced, and under the promotion of graphite, it combines with the phosphorus in the sewage to form blue iron stone. Blue iron stone gradually crystallizes and accumulates to form solid crystals with a particle size of microns. Due to the barrier of the filter membrane, it will not be lost by the water flow. Observe the pressure changes of the pressure sensor and the speed sensor. When the pressure value of the sensor exceeds the initial value by 50%, close the solenoid valve and the connecting valve, disassemble the trap, replace the filter membrane, centrifuge the precipitation in the trap, and vacuum dry and store the obtained product anaerobically. After the pipeline maintenance is completed, add the above filler again and install the trap for use. The blue iron stone recovery rate reaches 98%.

[0045] Embodiment 2:

[0046] Before the installation of the trap, ferrihydrite particles and activated carbon particles are added. The molar ratio of the carbon-based material to the iron ore is 1.7:1. The filter membrane is installed at the interface of the trap and fixed with a flange containing an annular sealing ring. The sewage flows through here and flows into the trap due to gravity. Under the action of the alienated iron-reducing microorganisms in the sewage, the iron in the ferrihydrite is reduced. Under the promotion of activated carbon, it combines with the phosphorus in the sewage to form blue iron. Blue iron gradually crystallizes and accumulates to form solid crystals with a particle size of microns. Observe the pressure changes of the pressure sensor and the speed sensor. When the speed sensor shows that the flow rate is 40% lower than the initial value, close the solenoid valve and the connecting valve, disassemble the trap, replace the filter membrane, and centrifuge the precipitate in the trap. The obtained product is vacuum dried and stored anaerobically. After the pipeline maintenance is completed, the above-mentioned filler is added again and the trap is installed for use. The blue iron recovery rate reaches 99%.

[0047] Embodiment 3:

[0048] Before the installation of the trap, hexagonal lepidocrocite particles are added. The molar ratio of the carbon-based material to the iron ore is 1.3:1. A filter membrane is installed at the interface of the trap and fixed using a flange containing an annular sealing ring. The sewage from the main pipeline flows through here and flows into the trap due to gravity. Under the action of alienated iron-reducing microorganisms in the sewage, the iron in the hexagonal lepidocrocite is reduced and combines with the phosphorus in the sewage to form blue iron. Blue iron gradually crystallizes and accumulates. Observe the pressure changes of the pressure sensor and the speed sensor. When the speed sensor shows that the flow rate is 50% lower than the initial value, close the solenoid valve and the connecting valve, disassemble the trap and replace the filter membrane, and the obtained product is vacuum dried and stored anaerobically. After the pipeline maintenance is completed, add the above-mentioned filler again and install the trap for use. The blue iron recovery rate reaches 98%.

[0049] Embodiment 4:

[0050] The trap is applied to the urban sewage network. The sewage from the urban industrial area, office area and residential area flows into the main pipeline, which contains a large amount of organic phosphorus and phosphate. The trap is installed at the inspection well interface of the pipeline, and its pipe diameter and material are consistent with the interface diameter and material. The trap is loaded with iron ore and carbon material, and the product blue iron stone is recovered during the maintenance of the pipeline network.

[0051] Embodiment 5:

[0052] The trap is applied to the sewer pipes of residential buildings. The domestic sewage from the kitchen sink, toilet, bathtub, and floor drain is rich in phosphorus and organic matter. The trap is installed at the confluence of the sewer pipes, and iron ore and carbon materials are loaded before installation. The trap is disassembled and the target product is collected during pipeline inspection and maintenance. This approach can make full use of the substances in the water and realize phosphorus recovery.

[0053] The above description is only a preferred embodiment of the present invention, but the embodiment and protection scope of the present invention are not limited thereto. Any changes, substitutions, combinations, modifications and simplifications made by any technician familiar with the technical field within the technical scope of the present invention based on the essence, principles and concepts of the present invention are considered to be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A device for recovering phosphorus in a sewage pipe network, connected to the sewage pipe network, characterized in that: A trap is arranged at the interface of the sewage pipe network, the trap is connected to the sewage pipe network by a flange, a solenoid valve is installed above the flange, a filter membrane is arranged below the flange, a reaction bed is arranged in the trap, the reaction bed is a multi-layer structure, each layer is arranged as a grid structure, and the distance between each adjacent layer is 1 / 3-1 / 5 of the height of the reaction bed; A carbon-based material is provided in the reaction bed, and iron ore is laid on the carbon-based material as a supplementary iron source, and the molar ratio of the carbon-based material to the iron ore is 1-1.7:1; A trap is arranged at each interval according to the sewage flow rate, a connecting valve is arranged at the bottom of each trap, a speed sensor is arranged at the bottom of the connecting valve, the connecting valve connects each trap through a connecting pipe, and a pressure sensor is arranged on the connecting pipe.

2. The device for recovering phosphorus in a sewage pipe network according to claim 1, characterized in that: The grid is arranged as a square grid or a diamond grid according to the morphological characteristics of the iron ore and the carbon-based material.

3. The device for recovering phosphorus in a sewage pipe network according to claim 1, characterized in that: An annular sealing gasket is installed at the connection between the flange and the catcher, and the flange material is consistent with the pipeline material.

4. The device for recovering phosphorus in a sewage pipe network according to claim 1, characterized in that: The filter membrane is used for intercepting and filtering impurities in sewage, and at the same time preventing the filler and the product blue iron stone in the collector from being washed out by the water flow. The pore size of the filter membrane is in the micron level.

5. The device for recovering phosphorus in a sewage pipe network according to claim 1, characterized in that: The iron ore is selected from lepidocrocite, ferrihydrite or hematite.

6. The device for recovering phosphorus in a sewage pipe network according to claim 1, characterized in that: The carbon-based material is selected from biochar, graphite or carbon black.

7. A method for in-situ enrichment and recovery of blue iron stone using the device for recovering phosphorus in a sewage pipe network according to any one of claims 1 to 6, characterized in that: The steps include: S1: Before installing the capture device, add carbon-based materials into the reaction bed, lay iron ore at the bottom of the reaction bed as a supplementary iron source, and the molar ratio of carbon-based materials to iron ore is 1-1.7:1; S2: Install the trap at the pipe network interface with flange connection. According to the designed flow rate of sewage pipe 1-1.5m / s, set a trap at every 0.5-1m interval in the pipe network; when the flow rate is <1m / s, the interval between the traps is controlled to be 1-2m; when the flow rate is greater than 1.5m / s, the interval between pipes is controlled to be 0.3-0.5m; S3: Open the solenoid valve and the connecting valve to connect the capture devices to achieve the flow of liquid medium; S4: Observe the pressure change of the pressure sensor and the speed sensor to determine whether the enrichment of the trap has been completed; S5: When the sensor pressure value exceeds the initial value by 50%, close the solenoid valve and the connecting valve; or The velocity sensor shows that the flow rate is 40% lower than the initial value, and the solenoid valve and the connecting valve are closed; S6: The collector is disassembled through the flange, and the contents in the reaction bed are centrifuged and dried to obtain the high value-added product blue iron stone.

8. The method according to claim 7, characterized in that The molar ratio of the carbon-based material to the iron ore is 1.1:

1.

9. The method according to claim 7, characterized in that: The molar ratio of the carbon-based material to the iron ore is 1.3:1.

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