Recycling of leachate treatment system of waste incineration power plant

Abstract

The utility model discloses a kind of leachate treatment systems of recycling garbage incineration power plant, including the pretreatment pool, anaerobic reactor, aerobic processor and membrane processing unit connected in turn, the pretreatment pool includes vertical cylindrical tank body, vertical cylindrical tank body is sequentially provided with cyclone mixing zone, flocculation reaction zone, centrifugal separation zone and clean water overflow area from below to top, the side of cyclone mixing zone bottom is equipped with tangential water inlet, tangential water inlet side is equipped with dosing port;The flocculation reaction zone is equipped with multiple layers of honeycomb flocculation flow guide plate that are distributed in slope from top to bottom;The central region of centrifugal separation zone upper portion is equipped with inverted conical separation cover, and clearance is formed between conical separation cover and vertical cylindrical tank body inner wall surface;The clean water overflow area is also equipped with clean water collection net groove.The utility model has the characteristics of can effectively reduce drug consumption and reduce floor area.

Description

Technical Field

[0001] This utility model relates to a waste incineration power plant treatment equipment, and more particularly to a waste incineration power plant leachate treatment system. Background Technology

[0002] Leachate from waste-to-energy plants is complex, containing high concentrations of organic matter (COD), ammonia nitrogen, salts, and heavy metals, among other pollutants. It has poor biodegradability and is extremely difficult to treat, earning it the nickname "king of wastewater." Currently, mainstream treatment processes typically employ pretreatment, anaerobic treatment, aerobic treatment, and membrane filtration. Pretreatment usually involves flocculation sedimentation tanks for coagulation and sedimentation. However, traditional flocculation sedimentation tanks have the following problems: 1) Mechanical agitators or pipeline mixers struggle to ensure instantaneous and uniform mixing of chemicals and wastewater when dealing with leachate exhibiting drastic fluctuations in water quality and quantity, resulting in poor coagulation and high chemical consumption. 2) From chemical dosing, mixing, flocculation to sedimentation, multiple independent structures or equipment units are required, resulting in a large overall footprint.

[0003] Therefore, existing technologies suffer from high drug consumption and large footprint. Summary of the Invention

[0004] The purpose of this invention is to provide a system for treating leachate from waste incineration power plants. This invention effectively reduces chemical consumption and floor space requirements.

[0005] The technical solution of this utility model is as follows: a leachate treatment system for waste incineration power plants, comprising a pretreatment tank, an anaerobic reactor, an aerobic processor, and a membrane treatment unit connected in sequence. The pretreatment tank comprises a vertical cylindrical tank, which, from bottom to top, is provided with a swirling mixing zone, a flocculation reaction zone, a centrifugal separation zone, and a clear water overflow zone. A tangential inlet is located on the side of the bottom of the swirling mixing zone, and a dosing port is located on the side of the tangential inlet. The flocculation reaction zone is provided with multiple layers of honeycomb-shaped flocculation guide plates distributed at varying angles. An inverted conical separation hood is located in the central area of ​​the upper part of the centrifugal separation zone, and a gap is formed between the conical separation hood and the inner wall of the vertical cylindrical tank. The clear water overflow zone is also provided with a clear water collection trough.

[0006] In the aforementioned leachate treatment system for waste-to-energy incineration plants, the adjacent honeycomb flocculation guide plates are tilted in opposite directions.

[0007] In the aforementioned leachate treatment system for waste incineration power plants, the bottom of the vertical cylindrical tank is also equipped with a cone-shaped sludge collection area, and the bottom of the cone-shaped sludge collection area is equipped with a sludge discharge port, which is equipped with a high-frequency intermittent sludge discharge valve.

[0008] Compared with existing technologies, the pretreatment tank of this invention consists of a vortex mixing zone, a flocculation reaction zone, a centrifugal separation zone, and a clear water overflow zone, integrating the three major functions of mixing, flocculation, and centrifugal separation into a single tank. This compact structure effectively reduces the floor space required. Furthermore, the vortex mixing zone uses a tangential inlet for water intake, with the dosing port positioned between adjacent tangential inlets. This tangential vortex mixing ensures efficient utilization of the chemicals, thereby effectively reducing chemical consumption. Moreover, the tangential inlet design creates a tangential vortex flow, enabling centrifugal separation of suspended solids. Compared to gravity sedimentation, centrifugal separation is faster and more efficient, resulting in better removal of light suspended solids. In summary, this invention effectively reduces chemical consumption and floor space requirements. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of this utility model.

[0010] The labels in the attached diagram are as follows: 1-Vertical cylindrical tank, 2-Swirl mixing zone, 3-Flocculation reaction zone, 4-Centrifugal separation zone, 5-Clear water overflow zone, 6-Tangential inlet, 7-Dosing port, 8-Honeycomb flocculation guide plate, 9-Conical separation hood, 10-Gap, 11-Clear water collection trough, 12-Conical sludge collection zone, 13-Sludge discharge port. Detailed Implementation

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0012] Example. A leachate treatment system for waste-to-energy incineration plants is configured as follows: Figure 1 As shown, the system includes a pretreatment tank, an anaerobic reactor, an aerobic processor, and a membrane treatment unit connected in sequence. The pretreatment tank includes a vertical cylindrical tank 1, which has a swirling mixing zone 2, a flocculation reaction zone 3, a centrifugal separation zone 4, and a clear water overflow zone 5 arranged sequentially from bottom to top. The bottom side of the swirling mixing zone 2 is provided with a tangential inlet 6, and the side of the tangential inlet 6 is provided with a dosing port 7. The flocculation reaction zone 3 is provided with multiple layers of honeycomb-shaped flocculation guide plates 8 that are inclined vertically. The central area of ​​the upper part of the centrifugal separation zone 4 is provided with an inverted conical separation hood 9, and a gap 10 is formed between the conical separation hood 9 and the inner wall of the vertical cylindrical tank 1. The clear water overflow zone 5 is also provided with a clear water collection trough 11.

[0013] The adjacent honeycomb-shaped flocculation guide plates 8 are tilted in opposite directions.

[0014] The bottom of the vertical cylindrical tank 1 is also provided with a cone-shaped mud collection area 12, and the bottom of the cone-shaped mud collection area 12 is provided with a mud discharge port 13, and the mud discharge port 13 is provided with a high-frequency intermittent mud discharge valve.

[0015] There are four tangential inlets, tangential to the side of the vertical cylindrical tank. Located at the bottom of the tank, wastewater enters through the tangential inlets in a high-speed jet state, mixing with the coagulant added through the dosing port, forming a strong swirling upward flow along the tank wall. Utilizing the fluid's own kinetic energy, instantaneous and intense mixing of the agent and wastewater is achieved, eliminating the need for additional mechanical stirring devices, resulting in energy savings and extremely high mixing efficiency.

[0016] The flocculation reaction zone, located above the swirling mixing zone, contains multiple layers of honeycomb-shaped flocculation guide plates suspended within it. These guide plates are at a certain angle to the horizontal plane, with adjacent layers tilting at opposite angles. As the swirling, rising water flows through these interlaced honeycomb guide plates, its flow direction is continuously altered, creating moderate turbulence. This provides an optimal energy environment for the collision and growth of microflocculation particles, promoting the formation of large, dense flocs.

[0017] In the centrifugal separation zone, above the flocculation reaction zone, an inverted conical separation hood is set in the center of the tank. An annular channel is formed between the conical separation hood and the inner wall of the tank. The water carrying flocs continues to rotate in the annular channel. Under the action of centrifugal force, the denser flocs are thrown towards the tank wall. After losing kinetic energy, they settle down to the bottom along the tank wall, thus achieving centrifugal separation.

[0018] At the bottom of the tank, there is a conical sludge collection area and a high-frequency intermittent sludge discharge valve. The sludge discharge valve is controlled by a timer or pressure sensor, and automatically and quickly opens for a few seconds at short intervals (such as 5-15 minutes), using the water pressure inside the tank to instantly discharge the concentrated sludge, thereby completely avoiding the sludge accumulation and clogging problems common in traditional sedimentation tanks.

[0019] The clear water overflow zone is located at the very top of the tank, with a radial water collection trough in the center. The treated supernatant collects in the central area and flows out through the collection trough. Working principle: After centrifugal separation, the clear water forms a relatively stable low-velocity zone in the central area, and is evenly collected and flows out through the clear water collection net trough at the top, ensuring the quality of the effluent.

[0020] The honeycomb-shaped flocculation guide plate, the conical separation hood, and the clear water collection trough are all suspended. A suspension rod is located at the center, which sequentially and detachably fixes the honeycomb-shaped flocculation guide plate, the conical separation hood, and the clear water collection trough together, and then suspends them into the tank. The working process of this invention: Leachate is pumped into the reactor through a tangential inlet by a booster pump, while coagulant is simultaneously injected through a reagent dosing port. The two mix instantaneously in the swirling mixing zone, then rotate and rise through the honeycomb-shaped guide plates in the flocculation reaction zone, forming flocs. In the centrifugal separation zone, the water flows through an inverted conical separation hood to achieve sludge-water centrifugal separation: sludge settles and concentrates along the tank wall in the conical sludge collection area (the forces and trajectory of the sludge (core): a sludge particle in the swirling field is mainly subjected to three forces: outward centrifugal force (Fc), inward pressure gradient force (Fp), and downward gravity (G) and water flow drag. For particles with a density greater than water, the centrifugal force Fc > the pressure gradient force Fp. This net outward force forces the particle to cross the streamlines and move radially to the tank wall. Upon reaching the tank wall, the particles lose their tangential velocity, and the centrifugal force decreases sharply. At this point, gravity G and the downward frictional force generated by the spiraling upward water flow on the wall dominate their motion, causing them to slide down the tank wall in a spiral trajectory. Therefore, the macroscopic movement path of the sludge is a three-dimensional trajectory of "outward -> spiral downward," eventually converging into the cone at the bottom. The sludge is periodically discharged by a high-frequency intermittent sludge discharge valve; the clean water collects in the center, rises to the clean water overflow area, is collected by the radial collection tank, and then enters the subsequent anaerobic reactor for treatment.

[0021] The tangential inlet is installed along the tangential direction of the cylindrical sidewall of the tank. When high-pressure water is injected tangentially into the cylindrical tank through this small opening, it does not rush directly to the center. Instead, it "turns" along the inner wall of the tank and spirals upwards. Subsequent water flows continue to be injected in this direction, pushing the preceding water to rotate as well, thus forming a stable and strong rotating water flow (vortex / vortex) inside the tank. The driving force for this rotation comes from the kinetic energy of the incoming water being converted into rotational momentum by the tangential inlet.

Claims

1. A leachate treatment system for waste incineration power plants, comprising a pretreatment tank, an anaerobic reactor, an aerobic processor, and a membrane treatment unit connected in sequence, characterized in that: The pretreatment tank includes a vertical cylindrical tank (1), which is provided with a swirling mixing zone (2), a flocculation reaction zone (3), a centrifugal separation zone (4) and a clear water overflow zone (5) from bottom to top. The bottom side of the swirling mixing zone (2) is provided with a tangential inlet (6), and the side of the tangential inlet (6) is provided with a dosing port (7). The flocculation reaction zone (3) is provided with a multi-layer honeycomb flocculation guide plate (8) with an upward and downward inclined distribution. The central area of ​​the upper part of the centrifugal separation zone (4) is provided with an inverted conical separation hood (9), and a gap (10) is formed between the conical separation hood (9) and the inner wall of the vertical cylindrical tank (1). The clear water overflow zone (5) is also provided with a clear water collection trough (11).

2. The leachate treatment system for waste incineration power plants according to claim 1, characterized in that: The adjacent honeycomb flocculation guide plates (8) are tilted in opposite directions.

3. The leachate treatment system for waste incineration power plants according to claim 1, characterized in that: The bottom of the vertical cylindrical tank (1) is also provided with a cone-shaped mud collection area (12), and the bottom of the cone-shaped mud collection area (12) is provided with a mud discharge port (13), and a high-frequency intermittent mud discharge valve is provided on the mud discharge port (13).

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