Treatment system for aging landfill leachate

Abstract

The utility model discloses an aging landfill leachate treatment system which comprises an adjusting tank, a lifting pump, a filtering tank, a primary aerobic tank, a primary anaerobic tank, a secondary aerobic tank, a dosing system, a backflow system, a membrane system water inlet pump and a membrane filtering system, the adjusting tank, the lifting pump, the filtering tank, the first-stage aerobic tank, the first-stage anaerobic tank, the second-stage aerobic tank, the membrane system water inlet pump and the membrane filtering system are sequentially communicated in the percolate flowing direction, and the dosing system and the backflow system are located on the two sides of the first-stage aerobic tank, the first-stage anaerobic tank and the second-stage aerobic tank respectively. The dosing system is communicated with the first-stage aerobic tank, the first-stage anaerobic tank and the second-stage aerobic tank through pipelines, and the second-stage aerobic tank is communicated with the first-stage aerobic tank and the first-stage anaerobic tank through pipelines by the reflux system. According to the utility model, a unique OAO process is set, the proportion of the tank body is adjusted, multi-point multi-gradient carbon source dosing is adopted, the carbon source utilization rate is improved, the equipment operation difficulty is reduced, the system operation is more stable, and the water quality change impact can be better coped with.

Description

Technical Field

[0001] The utility model relates to the technical field of landfill leachate treatment, in particular to a treatment system for aging landfill leachate. Background Art

[0002] The currently commonly used biochemical secondary AO denitrification treatment is mainly through the return of the primary nitrification liquid to the primary denitrification tank, the return of the secondary nitrification liquid to the secondary denitrification tank, or the direct return of the secondary nitrification liquid to the primary denitrification tank, which has incomplete overall utilization efficiency of the tank body. Application number: 202210031151.8, the patent name is an invention patent for a waterfall reoxygenation multi-stage AO rural domestic sewage treatment device, which discloses a waterfall reoxygenation multi-stage AO rural domestic sewage treatment device, including a stepped water distribution tank, an A tank, at least two stages of OA tanks, and an O tank. However, the AOA denitrification process is adopted in this technical solution. When the ammonia nitrogen concentration of the sewage exceeds 3000, the ammonia nitrogen concentration in the primary nitrification tank is prone to excessively high. At the same time, it will lead to a decrease in the denitrification residence time, incomplete utilization of the denitrification carbon source, and the consumption of more carbon sources at the aerobic end of nitrification. Not only will the carbon source be wasted, but it will also lead to the consumption of dissolved oxygen in the nitrification tank, affecting the nitrification effect. Therefore, it is necessary to develop a leachate treatment system for aging landfills to solve the above problems. Utility Model Content

[0003] The purpose of the utility model is to provide a treatment system for leachate from an aging landfill.

[0004] According to one aspect of the utility model, a treatment system for leachate from an aging landfill is provided, comprising a regulating tank, a lifting pump, a filter tank, a primary aerobic tank, a primary anaerobic tank, a secondary aerobic tank, a dosing system, a reflux system, a membrane system water inlet pump, and a membrane filtration system. The regulating tank, the lifting pump, the filter tank, the primary aerobic tank, the primary anaerobic tank, the secondary aerobic tank, the membrane system water inlet pump, and the membrane filtration system are sequentially connected along the flow direction of the leachate. The dosing system and the reflux system are respectively located on both sides of the primary aerobic tank, the primary anaerobic tank, and the secondary aerobic tank. The dosing system is connected to the primary aerobic tank, the primary anaerobic tank, and the secondary aerobic tank via a pipeline. The reflux system connects the secondary aerobic tank with the primary aerobic tank and the primary anaerobic tank via a pipeline.

[0005] In some embodiments, the primary anaerobic tank is divided into a first anoxic section and a second anoxic section adjacent to each other and having equal volumes, and the first anoxic section and the second anoxic section are connected to each other.

[0006] In some embodiments, the dosing system includes a carbon source tank, a carbon source pump, a defoamer tank, a defoamer pump, a caustic soda tank and a caustic soda pump, one end of the carbon source pump is connected to the carbon source tank, and the other end extends into the first anoxic section and the second anoxic section through a pipeline, one end of the defoamer pump is connected to the defoamer tank, and the other end extends into the primary aerobic tank and the secondary aerobic tank through a pipeline, and one end of the caustic soda pump is connected to the caustic soda tank, and the other end extends into the primary aerobic tank through a pipeline.

[0007] In some embodiments, the reflux system includes a first reflux pipe, a reflux pump, a second reflux pipe and three parallel reflux branches, one end of the first reflux pipe extends into the bottom of the secondary aerobic tank, and the other end is connected to the water inlet of the reflux pump, one end of the second reflux pipe is connected to the water outlet of the reflux pump, one end of the three reflux branches is vertically connected to the second reflux pipe, and the other ends extend into the primary aerobic tank, the first anoxic section and the second anoxic section respectively.

[0008] In some embodiments, the volume ratio of the primary aerobic tank, the primary anaerobic tank, and the secondary aerobic tank is 1.5:2:1.

[0009] In some embodiments, the present invention further includes a fan, and both the primary aerobic tank and the secondary aerobic tank are provided with aeration pipes, and the fan is connected to the aeration pipes through pipelines.

[0010] In some embodiments, the present invention also includes a sludge filter press system, which includes a sludge thickening tank, a filter press and a filtrate return pipe. The membrane filtration system is connected to the sludge thickening tank through a pipeline, and the sludge thickening tank is connected to the filter press through a pipeline. One end of the filtrate return pipe is connected to the filter press, and the other end is connected to the primary aerobic tank.

[0011] In some embodiments, the membrane filtration system includes an ultrafiltration membrane pool, a nanofiltration membrane pool and a reverse osmosis membrane pool connected in sequence along the flow direction of the leachate. The ultrafiltration membrane pool is provided with a sludge discharge pipe and a sludge return pipe. One end of the sludge discharge pipe is connected to the ultrafiltration membrane pool, and the other end is connected to the sludge concentration tank. One end of the sludge return pipe is connected to the sludge discharge pipe, and the other end is connected to the second return pipe. The reverse osmosis membrane pool is provided with a concentrated water return pipe, and the concentrated water return pipe is connected to the nanofiltration membrane pool.

[0012] The beneficial effects of the present invention are as follows: in view of the characteristics of leachate from aging landfills, the present invention sets up a unique OAO process, adjusts the proportions of the primary aerobic tank, the primary anaerobic tank and the secondary aerobic tank, and isolates the primary anaerobic tank to achieve the purpose of reducing the total nitrogen concentration at the rear end; adopts multi-point and multi-gradient carbon source dosing to effectively improve the carbon source utilization rate, reduce the carbon source addition amount, reduce the difficulty of equipment operation, make the system operation more stable, and better cope with the impact of water quality changes; adopts multi-point return of nitrification liquid and sludge to reduce the return of primary nitrification liquid, dilute the ammonia nitrogen in the front-end inlet water, reduce equipment power consumption, reduce equipment control points, and reduce the difficulty of operation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a structural schematic diagram of a system for treating leachate from an aging landfill according to the present invention. DETAILED DESCRIPTION

[0014] The present invention will be further described in detail below with reference to the embodiments.

[0015] refer to Figure 1 The utility model provides a treatment system for leachate from an aging landfill, comprising a regulating tank 1, a lifting pump 2, a filter tank 3, a primary aerobic tank 4, a primary anaerobic tank 5, a secondary aerobic tank 6, a dosing system 7, a reflux system, a membrane system water inlet pump 9, a membrane filtration system 10, a fan and a sludge filter press system.

[0016] The regulating tank 1, lift pump 2, filter tank 3, primary aerobic tank 4, primary anaerobic tank 5, secondary aerobic tank 6, membrane system inlet pump 9, and membrane filtration system 10 are sequentially connected along the leachate flow direction. The dosing system 7 and the return system are located on either side of the primary aerobic tank 4, the primary anaerobic tank 5, and the secondary aerobic tank 6, respectively.

[0017] The volume ratio of the primary aerobic tank 4, the primary anaerobic tank 5, and the secondary aerobic tank 6 is 1.5:2:1. The primary anaerobic tank 5 is divided into a first anoxic section 51 and a second anoxic section 52, adjacent to each other and of equal volume. The first anoxic section 51 and the second anoxic section 52 are interconnected. Aeration pipes 13 are provided in both the primary aerobic tank 4 and the secondary aerobic tank 6. A fan is connected to the aeration pipes 13 via a pipe. The primary aerobic tank 4, the primary anaerobic tank 5, and the secondary aerobic tank 6 perform nitrogen and phosphorus removal on the leachate. Leachate from aging landfills is characterized by low COD and high ammonia nitrogen, and its inherent carbon source is not efficiently utilized during the denitrification stage. The utility model adopts the OAO process, performs nitrification treatment directly after water inflow, and adjusts the tank body ratio of the first-level aerobic tank 4, the first-level anaerobic tank 5 and the second-level aerobic tank 6 to 1.5:2:1, increases the volume ratio of the first-level anaerobic tank 5, and performs a 1:1 partition on the first-level anaerobic tank 5, so as to achieve the purpose of reducing the total nitrogen concentration at the rear end.

[0018] The dosing system 7 includes a carbon source tank 71, a carbon source pump 72, a defoamer tank 73, a defoamer pump 74, a caustic soda tank 75, and a caustic soda pump 76. One end of the carbon source pump 72 is connected to the carbon source tank 71, and the other end extends into the first anoxic section 51 and the second anoxic section 52 through a pipeline. One end of the defoamer pump 74 is connected to the defoamer tank 73, and the other end extends into the primary aerobic tank 4 and the secondary aerobic tank 6 through a pipeline. One end of the caustic soda pump 76 is connected to the caustic soda tank 75, and the other end extends into the primary aerobic tank 4 through a pipeline. Carbon source is supplemented simultaneously in the first anoxic section 51 and the second anoxic section 52 as a denitrification carbon source for removing total nitrogen. The carbon source dosing ratio is 2:1. By multi-point gradient carbon source dosing, the carbon source utilization rate is higher and the carbon source dosage can be reduced by 20%. At the same time, gradient dosing can effectively reduce the total nitrogen content.

[0019] The reflux system includes a first reflux pipe 81, a reflux pump 82, a second reflux pipe 83, and three parallel reflux branches 84. One end of the first reflux pipe 81 extends into the bottom of the secondary aerobic tank 6, and the other end is connected to the water inlet of the reflux pump 82. One end of the second reflux pipe 83 is connected to the water outlet of the reflux pump 82. One end of the three reflux branches 84 is vertically connected to the second reflux pipe 83, and the other ends extend into the primary aerobic tank 4, the first anoxic section 51, and the second anoxic section 52, respectively. The nitrified liquid from the secondary aerobic tank 6 is returned to the primary aerobic tank 4 and the primary anaerobic tank 5 through the multi-point reflux method of the reflux system. The reflux ratio of the primary aerobic tank to the primary anaerobic tank is 7:3, which plays a dual role of reflux of nitrified liquid and sludge. It can not only dilute the ammonia nitrogen in the front-end water, but also bring back excess dissolved oxygen for utilization. This can indirectly reduce aeration energy consumption and increase the volume ratio of the single-stage denitrification tank. By increasing the concentration gradient in the two pools, the overall utilization efficiency of the carbon source can be improved, and while ensuring the treatment efficiency, the carbon source usage and operation control parameters can be reduced, thereby reducing the difficulty of operation.

[0020] The sludge filter press system includes a sludge thickening tank 121, a filter press 122, and a filtrate return pipe 123. The sludge discharge pipe 104 connects the sludge thickening tank 121 to the ultrafiltration membrane tank 101, and the sludge thickening tank 121 to the filter press 122. One end of the filtrate return pipe 123 is connected to the filter press 122, and the other end is connected to the primary aerobic tank 4. The filtrate from the filter press 122 is returned to the primary aerobic tank 4, diluting ammonia nitrogen from the upstream influent and returning excess dissolved oxygen for utilization.

[0021] The membrane filtration system 10 includes an ultrafiltration membrane tank 101, a nanofiltration membrane tank 102, and a reverse osmosis membrane tank 103, which are connected in sequence along the flow direction of the leachate. The ultrafiltration membrane tank 101 is provided with a sludge discharge pipe 104 and a sludge return pipe 105. One end of the sludge discharge pipe 104 is connected to the ultrafiltration membrane tank 101, and the other end is connected to the sludge thickening tank 121. One end of the sludge return pipe 105 is connected to the sludge discharge pipe 104, and the other end is connected to the second return pipe 83. The reverse osmosis membrane tank 103 is provided with a brine return pipe 106, which is connected to the nanofiltration membrane tank 102. The sludge generated by the ultrafiltration membrane tank 101 enters the sludge return pipe 105 and the sludge thickening tank 121 respectively through the sludge discharge pipe 104. Sludge entering sludge return pipe 105 flows through second return pipe 83 and three return branches into primary aerobic tank 4, first anoxic section 51, and second anoxic section 52 for further nitrogen and phosphorus removal. Sludge entering sludge thickening tank 121 undergoes sedimentation and concentration, then is filtered through filter press 122, and the resulting sludge cake is transported away.

[0022] The above are only some embodiments of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A system for treating leachate from an aging landfill, characterized in that: The invention comprises a regulating tank, a lifting pump, a filter tank, a primary aerobic tank, a primary anaerobic tank, a secondary aerobic tank, a dosing system, a reflux system, a membrane system water inlet pump and a membrane filtration system. The regulating tank, the lifting pump, the filter tank, the primary aerobic tank, the primary anaerobic tank, the secondary aerobic tank, the membrane system water inlet pump and the membrane filtration system are sequentially connected along the flow direction of the leachate. The dosing system and the reflux system are respectively located on both sides of the primary aerobic tank, the primary anaerobic tank and the secondary aerobic tank. The dosing system is connected to the primary aerobic tank, the primary anaerobic tank and the secondary aerobic tank through a pipeline. The reflux system connects the secondary aerobic tank with the primary aerobic tank and the primary anaerobic tank through a pipeline.

2. The treatment system for leachate from an aging landfill according to claim 1, characterized in that: The primary anaerobic tank is divided into a first anoxic section and a second anoxic section adjacent to each other and having equal volumes. The first anoxic section and the second anoxic section are interconnected.

3. The treatment system for leachate from an aged landfill according to claim 2, characterized in that: The dosing system includes a carbon source tank, a carbon source pump, a defoamer tank, a defoamer pump, a caustic soda tank and a caustic soda pump. One end of the carbon source pump is connected to the carbon source tank, and the other end extends into the first anoxic section and the second anoxic section through a pipeline. One end of the defoamer pump is connected to the defoamer tank, and the other end extends into the primary aerobic tank and the secondary aerobic tank through a pipeline. One end of the caustic soda pump is connected to the caustic soda tank, and the other end extends into the primary aerobic tank through a pipeline.

4. The treatment system for leachate from an aged landfill according to claim 2, characterized in that: The reflux system includes a first reflux pipe, a reflux pump, a second reflux pipe and three parallel reflux branches. One end of the first reflux pipe extends into the bottom of the secondary aerobic tank, and the other end is connected to the water inlet of the reflux pump. One end of the second reflux pipe is connected to the water outlet of the reflux pump. One end of the three reflux branches is vertically connected to the second reflux pipe, and the other ends extend into the primary aerobic tank, the first anoxic section and the second anoxic section respectively.

5. The treatment system for leachate from an aged landfill according to claim 1, characterized in that: The volume ratio of the primary aerobic tank, the primary anaerobic tank and the secondary aerobic tank is 1.5:2:

1.

6. The treatment system for leachate from an aged landfill according to claim 1, characterized in that: It also includes a fan. Aeration pipes are provided in the first-level aerobic tank and the second-level aerobic tank. The fan is connected to the aeration pipes through a pipeline.

7. The treatment system for leachate from an aged landfill according to claim 4, characterized in that: It also includes a sludge filter press system, which includes a sludge thickening tank, a filter press and a filtrate return pipe. The membrane filtration system is connected to the sludge thickening tank through a pipeline, and the sludge thickening tank is connected to the filter press through a pipeline. One end of the filtrate return pipe is connected to the filter press, and the other end is connected to the primary aerobic tank.

8. The system for treating leachate from an aged landfill according to claim 7, characterized in that: The membrane filtration system includes an ultrafiltration membrane pool, a nanofiltration membrane pool and a reverse osmosis membrane pool which are connected in sequence along the flow direction of the leachate. The ultrafiltration membrane pool is provided with a sludge discharge pipe and a sludge return pipe. One end of the sludge discharge pipe is connected to the ultrafiltration membrane pool, and the other end is connected to the sludge concentration tank. One end of the sludge return pipe is connected to the sludge discharge pipe, and the other end is connected to the second return pipe. The reverse osmosis membrane pool is provided with a concentrated water return pipe, and the concentrated water return pipe is connected to the nanofiltration membrane pool.

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