Water-saving landfill leachate treatment system

Abstract

The utility model relates to a water-saving type landfill leachate treatment system which comprises a pretreatment device, a biological treatment device is arranged behind the pretreatment device in a communicating manner, the biological treatment device comprises an anaerobic reactor and a two-stage anoxic-aerobic tank arranged behind the anaerobic reactor in a communicating manner, and an aerobic section of the two-stage anoxic-aerobic tank is connected with an indirect air cooling device; an ultrafiltration device is communicated behind the biological treatment device; a pipe network type high-pressure reverse osmosis system is arranged behind the ultrafiltration device in a communicating manner, and the pipe network type high-pressure reverse osmosis system is a two-stage pipe network type high-pressure reverse osmosis device. According to the system, the water discharge amount and the water consumption of the system are reduced by improving the recovery rate of the landfill leachate treatment system and adopting an indirect air cooling device, so that the aim of saving water is fulfilled.

Description

Technical Field

[0001] The utility model patent belongs to the technical field of leachate treatment, and in particular relates to a water-saving garbage leachate treatment system. Background Art

[0002] With the advancement of my country's new urbanization strategy, it is expected that the urban population will show a high growth trend in the future, and the amount of garbage generated will also increase accordingly. Landfill and incineration are the main methods of garbage disposal in my country at this stage. Regardless of which method is used, landfills, transfer stations and incineration sites will produce a large amount of highly polluting garbage leachate, which will cause serious pollution to water, soil and air if not properly handled.

[0003] Before the garbage in the garbage power plant is incinerated, the fresh garbage is usually fermented and matured in the garbage storage pit for 3 to 7 days to drain out water and increase the calorific value of the garbage, which is conducive to the normal operation of incineration power generation and subsequent systems. This highly concentrated wastewater with extremely complex components is called leachate, which is one of the main secondary pollution products of garbage power plants. Garbage leachate is generally dark brown and contains a large amount of organic pollutants. It also dissolves and carries pollutants such as ammonia nitrogen, bacteria, viruses, and heavy metal ions. If it is not properly handled, it will seriously pollute the surrounding environment and threaten the health of the general public. Therefore, it is necessary to effectively treat the garbage leachate to minimize its impact on the environment.

[0004] In the technical route of landfill leachate treatment, "pretreatment + biological treatment + deep treatment" has gradually become the mainstream. Among them, "deep treatment" is mainly based on nanofiltration (a molecular separation technology with a separation membrane with nanometer pores, a functional semi-permeable membrane that allows solvent molecules or certain low molecular weight solutes or low-valent ions to pass through, and a membrane separation device between reverse osmosis and ultrafiltration) + conventional reverse osmosis membrane treatment process. For landfill leachate with high salt content and poor biodegradability, it is necessary to operate at a lower recovery rate, which leads to a large amount of wastewater discharge.

[0005] Biological treatment includes anaerobic biological treatment and anoxic and aerobic biological treatment. Since the biochemical heat release of the system is large during aerobic biological treatment, a cooling system must be set up to exchange and cool the heat generated by the aerobic system to prevent the biochemical system from heating up continuously and causing the death of microorganisms. Usually, the open-loop cooling water secondary circulation method is adopted, which has the problem of high water consumption. Utility Model Content

[0006] In order to solve the problem of high water consumption in existing garbage leachate treatment systems, this patent proposes a water-saving garbage leachate treatment system, which is more conducive to reducing the amount of wastewater in the garbage leachate treatment system and reducing the water consumption of the system, thereby achieving the purpose of water saving.

[0007] The technical means adopted by the utility model are as follows:

[0008] A water-saving garbage leachate treatment system, comprising:

[0009] Pretreatment device;

[0010] A biological treatment device is connected to the pretreatment device;

[0011] An ultrafiltration device is connected to the biological treatment device and arranged behind it;

[0012] A pipe network type high pressure reverse osmosis system is connected to the ultrafiltration device.

[0013] Preferably, the pipe network type high pressure reverse osmosis system is a two-stage pipe network type high pressure reverse osmosis device.

[0014] Preferably, the biological treatment device comprises an anaerobic reactor and two-stage anoxic and aerobic tanks connected and arranged after the anaerobic reactor.

[0015] Preferably, the aerobic section of the two-stage anoxic aerobic pool is connected to an indirect air cooling device.

[0016] Preferably, the pretreatment device includes a grid and a pre-sedimentation tank.

[0017] Preferably, a regulating tank is connected between the pre-sedimentation tank and the anaerobic reactor.

[0018] Preferably, the ultrafiltration device is an MBR ultrafiltration membrane.

[0019] Preferably, a sludge dewatering system is also provided, and the sludge discharge outlets of the pretreatment device, the anaerobic reactor and the anoxic aerobic tank are connected to a sludge collection tank through a first recovery pipe, and the sludge collection tank is then connected to the sludge dewatering system, and the water outlet of the sludge dewatering system is connected to the connecting pipe between the anaerobic reactor and the anoxic aerobic tank through a second recovery pipe.

[0020] Preferably, a first circulation pipeline is further provided between the connecting pipeline between the anaerobic reactor and the anoxic aerobic tank and the connecting pipeline between the regulating tank and the anaerobic reactor.

[0021] Preferably, a second circulation pipeline is further provided between the connecting pipelines between the ultrafiltration device and the anaerobic reactor and the anoxic aerobic tank.

[0022] Compared with the prior art, the beneficial effects achieved by this solution are:

[0023] 1. This scheme uses a pipe network high-pressure reverse osmosis device for the garbage leachate treatment system to improve the system recovery rate and reduce the system drainage volume.

[0024] 2. This system uses an indirect air cooling device to minimize the system water consumption and improve the water-saving effect of the entire unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall process flow of the utility model.

[0026] In the figure:

[0027] 1 grille;

[0028] 2 Pre-sedimentation tank;

[0029] 3 regulating pool;

[0030] 4 anaerobic reactor;

[0031] 5 two-stage anoxic and aerobic pools;

[0032] 6. Indirect air cooling device;

[0033] 7. Ultrafiltration device;

[0034] 8. Pipe network high pressure reverse osmosis system;

[0035] 9. Sludge collection tank;

[0036] 10. Sludge dewatering system;

[0037] 11 first recovery pipeline;

[0038] 12 second recovery pipeline;

[0039] 13 first circulation pipeline;

[0040] 14. Second circulation pipeline. DETAILED DESCRIPTION

[0041] like Figure 1 As shown, a water-saving garbage leachate treatment system is proposed, comprising:

[0042] The pretreatment device includes a screen 1 and a pre-sedimentation tank 2, wherein the screen 1 is mainly used to intercept debris in the landfill leachate, and the pre-sedimentation tank 2 is mainly used to remove solid suspended matter that can be precipitated in the sewage, and remove inorganic particles and organic matter before biological treatment to ensure the normal operation of subsequent treatment.

[0043] A biological treatment device is connected to the pretreatment device, and the biological treatment device includes an anaerobic reactor 4 and a two-stage anoxic aerobic tank 5 connected to the anaerobic reactor 4. The anaerobic reactor 4 is a high-load organic pollutant treatment method with low energy consumption in the treatment process. It is often used in the treatment process of high-concentration organic wastewater and is used as a pre-treatment process for aerobic biochemical treatment. The process of the two-stage anoxic aerobic tank 5 is divided into an anoxic section and an aerobic section, or is divided into an anoxic period and an aerobic period in the operating period. Carbon oxidation process and nitrification process occur in the aerobic section, and denitrification process occurs by refluxing the mixed liquid to the anoxic section or entering the anoxic biochemical reaction period, completing the nitrification / denitrification denitrification process.

[0044] In the two-stage anoxic aerobic pool 5, since the biochemical heat release of the aerobic system is relatively large, the present solution is provided with an indirect air cooling device 6 connected to the aerobic section of the two-stage anoxic aerobic pool 5. The indirect air cooling device 6 is a cooling method that uses air to replace water as a cooling medium, uses an air cooling tower to replace a wet cooling tower, and uses a closed circulating cooling water system to replace an open circulating cooling water system, and the circulating water uses demineralized water. The cooling pipe is placed in the aerobic section, and the circulating cooling water takes away the heat generated by the aerobic section, and after being cooled by the air cooling tower, it is pumped into the aerobic section by a water pump, and the cycle is repeated to perform heat exchange cooling and cooling on the aerobic section, so as to prevent the biochemical system from continuously heating up and causing the death of microorganisms, so as to meet the process requirements.

[0045] Since the amount of leachate water is not uniform within a day, a regulating tank 3 with a certain volume is also connected between the pre-sedimentation tank 2 and the anaerobic reactor 4 to buffer the impact load that may be caused by uneven water inflow. At the same time, a longer hydraulic retention time can have a certain hydrolysis and acidification function, improving the biodegradability of water quality.

[0046] An ultrafiltration device 7 is connected to the biological treatment device and is an external MBR ultrafiltration membrane.

[0047] A pipe network type high pressure reverse osmosis system 8 is connected to the ultrafiltration device 7. The pipe network type high pressure reverse osmosis system 8 is a two-stage pipe network type high pressure reverse osmosis device. The pipe network type high pressure reverse osmosis device combines some advantages of the roll membrane and the disc membrane, has an open flow channel, and the grid adopts a trapezoidal structure. The resistance is much smaller than the traditional reverse osmosis diamond grid. Its pollution resistance is better than that of the traditional reverse osmosis. It is a reverse osmosis membrane component that is both resistant to pollution and has a high flux. The working principle is the same as that of the roll reverse osmosis membrane, but the pressure resistance level is higher than that of the traditional reverse osmosis device. In a specific embodiment, the garbage leachate after ultrafiltration treatment enters the first-stage pipe network type high pressure reverse osmosis device, and the produced water enters the second-stage pipe network type high pressure reverse osmosis device for further treatment, and the concentrated water goes to the concentrated water tank. Technical parameters of the first-stage pipe network type high pressure reverse osmosis device: Q=6m 3 / h, the technical parameters of the water inlet pump of the first-stage pipe network high-pressure reverse osmosis device: vertical multi-stage centrifugal pump, Q = 6.5m3 / h, H = 40m. The water produced by the two-stage pipe network high-pressure reverse osmosis device is recycled and the concentrated water is sent to the concentrated water tank. Technical parameters of the two-stage pipe network high-pressure reverse osmosis device: Q = 5m 3 / h, two-stage pipe network high-pressure reverse osmosis device water inlet pump technical parameters: vertical multi-stage centrifugal pump, Q = 6m 3 / h, H=30m.

[0048] The above-mentioned pretreatment device (grid 1 and pre-sedimentation tank 2), regulating tank 3, anaerobic reactor 4, two-stage anoxic aerobic tank 5, ultrafiltration device 7, and pipe network type high-pressure reverse osmosis system 8 are connected through necessary pipelines to transport the leachate treated at each level. Control valves, instruments and other devices are set on the pipelines according to actual needs.

[0049] And if Figure 1 As shown, the system is provided with a first circulation pipeline 13 between the connecting pipeline between the anaerobic reactor 4 and the anoxic aerobic tank and the connecting pipeline between the regulating tank 3 and the anaerobic reactor 4; and a second circulation pipeline 14 is provided between the ultrafiltration device 7 and the connecting pipeline between the anaerobic reactor 4 and the anoxic aerobic tank. Through repeated treatment, the quality of the produced water meets the requirements for reuse or discharge.

[0050] The system is also provided with a sludge dewatering system 10. The sludge discharge outlets of the pretreatment device, the anaerobic reactor 4, and the anoxic aerobic tank are connected to a sludge collection tank 9 through a first recovery pipe 11. The sludge collection tank 9 is then connected to the sludge dewatering system 10. The sludge dewatering system 10 dewaters the sludge. The water outlet of the sludge dewatering system 10 is connected to the connecting pipe between the anaerobic reactor 4 and the anoxic aerobic tank through a second recovery pipe 12 to further recycle the dewatered water, and the remaining mud cake is transported to landfill.

[0051] The process of treating landfill leachate with the help of this system is as follows:

[0052] S1: The garbage leachate passes through the screen 1, the pre-sedimentation tank 2 and the regulating tank 3, and enters the anaerobic reactor 4. The anaerobic microorganisms in the anaerobic reactor 4 decompose the complex and difficult-to-degrade organic matter into low-level and simpler organic matter.

[0053] S2: After anaerobic treatment, the garbage leachate enters the anoxic aerobic tank to remove the main pollutants in the leachate, such as biodegradable organic pollutants, nitrogen, and phosphorus.

[0054] S3: The landfill leachate after biochemical treatment enters the ultrafiltration device 7+ two-stage pipe network high-pressure reverse osmosis membrane deep treatment system to further remove the difficult-to-biodegrade organic matter and dissolved salts that have not been removed after biological treatment, so that the water quality meets the requirements for reuse or discharge.

[0055] S4: The sludge produced by the reaction between the anaerobic reactor 4 and the anoxic aerobic tank is sent to the dehydration system through the sludge collection tank 9 for dehydration, and then transported to landfill.

[0056] The above-mentioned process system can achieve the purpose of water saving by improving the recovery rate of the garbage leachate treatment system and reducing the system drainage and water consumption by adopting measures such as an indirect air cooling device 6.

Claims

1. A water-saving garbage leachate treatment system, characterized in that: include: Pretreatment device; The pretreatment device comprises a grid (1) and a pre-sedimentation tank (2); A biological treatment device is connected to the back of the pretreatment device; the biological treatment device comprises an anaerobic reactor (4) and a two-stage anoxic aerobic tank (5) connected to the back of the anaerobic reactor (4); an indirect air cooling device (6) is connected to the aerobic section of the two-stage anoxic aerobic tank (5); An ultrafiltration device (7) is connected to the biological treatment device and is provided thereafter; the ultrafiltration device (7) is an MBR ultrafiltration membrane; A pipe network type high pressure reverse osmosis system (8) is connected to the ultrafiltration device (7) and arranged behind it; the pipe network type high pressure reverse osmosis system (8) is a two-stage pipe network type high pressure reverse osmosis device.

2. A water-saving garbage leachate treatment system according to claim 1, characterized in that: A regulating tank (3) is also provided between the pre-sedimentation tank (2) and the anaerobic reactor (4).

3. A water-saving garbage leachate treatment system according to claim 1, characterized in that: A sludge dewatering system (10) is also provided. The sludge discharge outlets of the pretreatment device, the anaerobic reactor (4) and the anoxic aerobic tank are connected to a sludge collection tank (9) through a first recovery pipe (11). The sludge collection tank (9) is then connected to the sludge dewatering system (10). The water production outlet of the sludge dewatering system (10) is connected to the connecting pipe between the anaerobic reactor (4) and the anoxic aerobic tank through a second recovery pipe (12).

4. A water-saving garbage leachate treatment system according to claim 2, characterized in that: A first circulation pipeline (13) is also provided between the connecting pipeline between the anaerobic reactor (4) and the anoxic aerobic tank and the connecting pipeline between the regulating tank (3) and the anaerobic reactor (4).

5. A water-saving garbage leachate treatment system according to claim 2, characterized in that: A second circulation pipeline (14) is also provided between the connecting pipelines between the ultrafiltration device (7) and the anaerobic reactor (4) and the anoxic and aerobic tank.

Images