Ecological purification system for tail water of water treatment plant

Abstract

The invention relates to the technical field of sewage treatment, and discloses a water treatment plant tail water ecological purification system, which comprises a tail water pool, a precipitation purification unit, an adsorption filtration unit, an ecological purification unit and a drainage pool which are sequentially communicated, and the adsorption filtration unit comprises an adsorption layer formed by splicing adsorption bricks; a plurality of parallel backwashing pipes are arranged below each adsorption layer, a plurality of through holes facing the bottom surfaces of the adsorption bricks are formed in the backwashing pipes, and mounting grooves allowing the backwashing pipes to be clamped in are formed in the bottom surfaces of the adsorption bricks; one end of the backwashing pipe is communicated with a water inlet pipe provided with a water pump, the other end of the backwashing pipe is communicated with a water return pipe provided with a control valve, and the water return pipe is used for returning water in the water purification area where the backwashing pipe communicated with the water return pipe is located to the water purification area on the upper layer. The ecological purification system for the tail water of the water treatment plant can effectively purify the tail water, remarkably reduce the pollutant concentration and reduce the influence on the water body, and meanwhile, the assembled adsorption layer can be detached and replaced, so that the maintenance is more convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to an ecological purification system for tail water of a water treatment plant. Background Art

[0002] The construction and operation of sewage treatment plants have reduced the pollution load of surface water to a certain extent, and effectively ensured the environmental quality and function of surface water. However, based on the fact that most sewage treatment plants implement the Class B discharge standard in the national "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB18918-2002), and according to the water area function and classification standards in the "Surface Water Environmental Quality Standard" (GB3838-2002), the minimum standard for surface water is Class V water, which is mainly applicable to agricultural water use areas and general landscape water areas. Comparison of the main indicators in the two standards shows that the current sewage treatment plant discharge standard is still inferior to the Class V standard for surface water, indicating that even if the tail water of the sewage treatment plant meets the discharge standard, it will still aggravate the deterioration of the surface water environment. Therefore, a system for re-treatment of the tail water of the sewage treatment plant should be designed to make the tail water meet the "Surface Water Environmental Quality Standard" and reduce the harm of the tail water to the surface environment. Summary of the invention

[0003] The purpose of the present invention is to provide a water treatment plant tail water ecological purification system.

[0004] In order to achieve the above object, the technical solution specifically provided by the present invention is as follows:

[0005] A water treatment plant tailwater ecological purification system, comprising a tailwater pool, a sedimentation purification unit, an adsorption filtration unit, an ecological purification unit and a drainage pool connected in sequence, wherein the adsorption filtration unit is used to adsorb and intercept pollutants in the tailwater after sedimentation purification, and comprises an adsorption pool and a plurality of adsorption layers arranged at intervals in the adsorption pool, wherein the adsorption layers divide the space in the adsorption pool into a plurality of clean water areas; the adsorption layers comprise a plurality of hollow adsorption bricks made of permeable concrete arranged in a rectangular array, wherein the inner cavity of the adsorption bricks is filled with adsorption filter material; below each adsorption layer A plurality of parallel backwash pipes are provided, and a plurality of through holes facing the bottom surface of the adsorption brick are opened on the backwash pipe; the bottom surface of the adsorption brick is provided with a mounting groove for the backwash pipe to be inserted; one end of the backwash pipe is connected to a water inlet pipe, and the water inlet pipe is used to supply water from the clean water area where the backwash pipe connected to it is located to the backwash pipe; the other end of the backwash pipe is connected to a return pipe, and the return pipe is used to return water from the clean water area where the backwash pipe connected to it is located to the clean water area on the upper layer; the water inlet pipe is connected to a water pump, and the return pipe is installed with a control valve that can be intermittently closed.

[0006] By adopting the above technical solution, the adsorption filter material is filled in the adsorption brick, and the adsorption brick can be replaced regularly, avoiding the problem that the conventional activated carbon adsorption unit is inconvenient to maintain after the activated carbon adsorption reaches saturation. In addition, in the normal working state, with the help of the water inlet pipe, backwash pipe and return pipe, the water in the lower purification area can be introduced into the upper purification area for secondary adsorption filtration, thereby improving the purification effect; during the purification process, the control valve is intermittently closed, and the water flows out from the through hole on the backwash pipe, which plays a backwashing role on the adsorption brick, prolonging the time for the adsorption filter material in the adsorption brick to reach adsorption saturation, thereby reducing the replacement frequency. The concentration of pollutants in the tail water that has been purified and treated by the sedimentation purification unit, adsorption filtration unit, and ecological purification unit in sequence is significantly reduced, reducing the negative impact on the receiving water body after discharge.

[0007] Furthermore, the adsorption brick comprises a brick body and a cover body, the four corners of the bottom surface of the cover body are provided with card blocks, and the four corners of the top surface of the brick body are provided with card slots for the card blocks to be inserted into. The brick body of the adsorption brick can be reused, and after the adsorption brick reaches adsorption saturation, the inner cavity adsorption filter material can be replaced.

[0008] Furthermore, the adsorption filter material includes an activated carbon adsorption layer filled in the brick body cavity from bottom to top, with a density of 100-150kg / m 3 The expanded granite layer, expanded ceramsite layer and quartz sand layer are arranged in layers, which have excellent adsorption and purification effects and can effectively remove suspended particles, organic matter and other pollutants in the tail water.

[0009] Furthermore, the filling volume ratio of the activated carbon adsorption layer, the expanded granite layer, the expanded ceramsite layer and the quartz sand layer is 1:1.5:2:3.

[0010] Furthermore, the backwash pipe is sleeved with a plurality of mounting rings, and the mounting rings are provided with a plurality of abutting pieces spaced apart along the circumferential direction, and the abutting pieces abut against the side walls of the mounting grooves, so that the pipe wall of the backwash pipe does not contact the mounting grooves. On the one hand, the placement stability of the adsorption bricks is increased, and on the other hand, the backwash pipe does not directly contact the adsorption bricks, and the backwash effect is better.

[0011] Furthermore, the abutment member includes an insert tube fixed to the mounting ring, an insert rod inserted in the insert tube, and an abutment block fixed to the end of the insert rod; the insert tube is arranged radially along the mounting ring, and an elastic member capable of generating an axial elastic force along the insert tube is arranged inside the insert tube, and an anti-dropping member for preventing the insert rod from being separated from the insert tube is arranged at the tube mouth; the abutment block has an abutment arc surface adapted to the arc of the mounting groove wall. This further increases the placement stability of the adsorption brick, and can adapt to mounting grooves of different sizes, thereby increasing the size tolerance in manufacturing the adsorption brick.

[0012] Furthermore, the ecological purification unit is used to purify the water discharged from the bottom water purification area of ​​the adsorption pool, and includes an ecological pool, in which aquatic plants are planted, and an algae biological carrier and an oxygen dissolver are provided. The aquatic plants have a fixation and purification effect on a small amount of pollutants remaining in the water body; the oxygen dissolver is used to increase the dissolved oxygen content of the water body; the algae biological carrier is used for algae biological attachment and growth, and the attached algae biological can also perform biological filtration on the water body, reduce pollution in external water, reduce turbidity, and improve water quality. Ecological ponds can be adapted to local conditions and can be transformed from existing small ponds, ditches, depressions, etc. Aquatic plants are preferably native plants, specifically reed (Phragmites australis (Cav.) Trin. ex Steud.), lotus (Nelumbo nucifera), water plantain (Schoenoplectus tabernaemontani (CCGmelin) Palla), cattail (Typha orientalis Presl), calamus (Acorus calamus L.) and loosestrife (Lythrum salicaria L.); algae can also be added as needed, such as pink-green foxtail algae (Myriophyllum aquaticum), Elodeanuttallii, black algae (Hydrillaverticillata), duckweed (Ceratophyllum demersum), etc., all of which have different degrees of purification effects on nitrogen and phosphorus pollutants in water bodies.

[0013] Furthermore, the aquatic plants are submerged plants and / or emergent plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the ecological purification system of tail water of a water treatment plant in Example 1;

[0015] Figure 2 is a schematic structural diagram of the adsorption filtration unit in Example 1;

[0016] Figure 3 Schematic diagram of the structure of the adsorption layer in Example 1;

[0017] Figure 4 This is a schematic diagram of the explosion of the adsorption brick in Example 1;

[0018] Figure 5 is a cross-sectional view of the adsorption brick in Example 1;

[0019] Figure 6 for Figure 5 A magnified view of part A;

[0020] Figure 7is a cross-sectional view of the adsorption brick in Example 2;

[0021] Figure 8 This is a schematic diagram of the structure of the mounting ring and the support arm in Example 2.

[0022] Description of reference numerals:

[0023] 1. Tailwater pool; 2. Sedimentation purification unit; 3. Adsorption filtration unit; 31. Adsorption pool; 32. Adsorption layer; 33. Water purification area; 34. Adsorption brick; 341. Brick body; 3411. Installation slot; 3412. Card slot; 342. Cover body; 3421. Card block; 35. Backwash pipe; 36. Water inlet pipe; 361. Water pump; 37. Return pipe; 371. Control valve; 38. Adsorption filter material; 381. Activated carbon adsorption layer; 382. Expansion flower Granite layer; 383, expanded expanded clay layer; 384, quartz sand layer; 4, ecological purification unit; 41, ecological pool; 42, algae biological carrier; 43, aquatic plants; 5, drainage pool; 6, sludge pool; 7, filter press; 8, mounting ring; 81, insert pipe; 82, insert rod; 83, abutment block; 831, abutment arc surface; 84, elastic part; 85, anti-slip part; 86, support arm; 861, connecting section; 862, arc section; 863, straight section. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0025] [Example 1]

[0026] A water treatment plant tail water ecological purification system, referring to Figure 1 , including a tailwater pool 1, a sedimentation purification unit 2, an adsorption filtration unit 3, an ecological purification unit 4 and a drainage pool 5 which are connected in sequence. The units can be connected by pipelines, ditches, etc., which are the connection methods known to those skilled in the art, so the specific connection methods will not be described in detail.

[0027] Reference Figure 1 The tailwater pool 1 is used to collect and temporarily store tailwater discharged from the water treatment plant, and after blending the tailwater with different pollutant concentrations, it is introduced into the subsequent treatment units for purification. After blending the tailwater, it is introduced into the subsequent purification units, and the water quality changes little, which is conducive to the stable performance of the subsequent treatment units.

[0028] Reference Figure 1The sedimentation purification unit 2 is used to precipitate and remove large particle pollutants suspended in the tail water, significantly reduce the concentration and turbidity of tail water pollutants, and ensure that the subsequent purification units can operate smoothly. Flocculants and flotation methods can be used in the sedimentation purification unit 2. The floating pollutants can be scraped off by a scraping device, and the sunken sludge can be led out and treated separately. In this embodiment, the sedimentation purification unit 2 includes a sludge pool 6 for collecting and discharging sludge and a filter press 7 for filtering the sludge; after adding the agent to the sludge pool 6, the high-water content mud with the agent is introduced into the filter press 7 for pressure filtration, and the filtered sewage is further purified after returning. The filtered sludge can be treated separately, such as further heat treatment to remove organic pollutants, harmless landfill, etc.

[0029] Reference Figure 1 and Figure 2 The adsorption and filtration unit 3 is used to further purify and remove impurities from the tail water treated by the sedimentation and purification unit 2. The adsorption and filtration unit 3 includes an adsorption tank 31 and a plurality of adsorption layers 32 arranged in parallel and spaced in the adsorption tank 31. The plurality of adsorption layers 32 divide the inner cavity of the adsorption tank 31 into a plurality of clean water areas 33. In this embodiment, the adsorption layer 32 is provided with two layers.

[0030] Reference Figure 2 , Figure 3 and Figure 4 The adsorption layer 32 is composed of a plurality of adsorption bricks 34 filled with adsorption filter material 38, and each adsorption brick 34 is arranged in a rectangular array. The adsorption brick 34 is a hollow rectangular block, molded from permeable concrete, and includes a brick body 341 and a detachable cover body 342. The four corners of the top opening of the brick body 341 are provided with card slots 3412, and the four corners of the bottom surface of the cover body 342 are provided with card blocks 3421 for carding into the card slots 3412. When the cover body 342 is buckled onto the brick body 341, the card block 3421 is carded into the card slot 3412.

[0031] Reference Figure 3 , Figure 4 and Figure 5 The adsorption filter material 38 includes four different porous adsorption materials. From bottom to top, the inner cavity of the adsorption brick 34 is filled with an activated carbon adsorption layer 381, an expanded granite layer 382, ​​an expanded ceramsite layer 383 and a quartz sand layer 384. To ensure a good adsorption and filtration effect, the filling volume ratio of the activated carbon adsorption layer 381, the expanded granite layer 382, ​​the expanded ceramsite layer 383 and the quartz sand layer 384 is controlled to be 1:1.5:2:3. Among them, the density of the expanded granite layer 382 is 100-150kg / m 3 The expanded granite in this density range has excellent adsorption and strength, and is not easy to break while ensuring the adsorption and filtration effect.

[0032] Reference Figure 2 , Figure 3 and Figure 5 , a number of mutually parallel backwash pipes 35 are provided below the adsorption layer 32. In this embodiment, the backwash pipe 35 is arranged along the length direction of the adsorption brick 34, and the bottom surface of the adsorption brick 34 is concave to form a mounting groove 3411 for the backwash pipe 35 to be inserted. The backwash pipe 35 is provided with a number of through holes facing the side wall of the mounting groove 3411. In this embodiment, the cross section of the mounting groove 3411 is semicircular. The water outlet ends of the backwash pipes 35 of the same layer are all connected to the return pipe 37, and the control valve 371 is installed on the return pipe 37 and the end is connected to the clean water area 33 of the upper layer, and the control valve 371 can be closed intermittently; the water inlet ends of the backwash pipes 35 of the same layer are connected to the same water inlet pipe 36, and the water pump 361 is installed on the water inlet pipe 36, which is used to introduce the water of the clean water area 33 where the backwash pipes 35 of this layer are located into the backwash pipe 35. In this way, through the cooperation between the water pump 361 and the control valve 371 that can be closed intermittently, the following are achieved: A. Promoting adsorption purification. When the control valve 371 is in the open state, under the action of the water pump 361, the water in the next layer of the clean water area 33 flows through the water inlet pipe 36, the backwash pipe 35 and the return pipe 37 in sequence, and is introduced into the upper layer of the clean water area 33, and then passes through the adsorption layer 32 for the second time to complete the secondary purification; B. Backwashing. When the control valve 371 is in the closed state, under the action of the water pump 361, the water is sprayed out from the through hole on the backwash pipe 35 with a high-pressure water flow to flush the adsorption bricks 34, thereby extending the time for the adsorption bricks 34 to reach the adsorption saturation state and reducing the frequency of replacement of the adsorption bricks 34.

[0033] Reference Figure 5 and Figure 6In order to increase the assembly stability of the adsorption brick 34, a number of abutments are installed on the backwash pipe 35. The abutments are spaced along the circumference of the backwash pipe 35 to support the backwash pipe 35 and the wall of the mounting groove 3411, so that the wall of the mounting groove 3411 does not directly contact the backwash pipe 35. The backwash pipe 35 is fixed with a mounting ring 8. In this embodiment, the abutment includes a plug 81 fixed to the mounting ring 8. The plug 81 is arranged along the radial direction of the mounting ring 8. A plug rod 82 is inserted into the plug 81, and a protrusion is provided at one end of the plug rod 82 inserted into the plug 81, and an anti-slip part 85 is provided at the opening of the plug 81, so that the plug rod 82 can move axially along the plug 81 without being separated from the plug 81. An elastic part 84 that can provide axial elastic force along the plug 81 is also provided in the plug 81. In this embodiment, the elastic member 84 is a compression spring sleeved on the plug rod 82. An abutment block 83 is fixedly provided at one end of the plug rod 82 away from the mounting ring 8. The abutment block 83 has an abutment arc surface 831 adapted to the curvature of the side wall of the mounting groove 3411. When the backwash pipe 35 is inserted into the mounting groove 3411, the abutment block 83 is mortgaged and retracted. At this time, the compression spring is stretched and the plug rod 82 is retracted into the plug pipe 81. In this way, when the backwash pipe 35 is inserted into the mounting groove 3411 of different sizes, it can automatically adapt to the groove wall of the mounting groove 3411 through the telescopic movement of the plug rod 82. The adsorption brick 34 is made of permeable concrete with a relatively rough surface. The adaptive abutment can reduce the dimensional accuracy requirements for the adsorption brick 34. After the tail water treated by the adsorption filtration unit 3, the suspended particles and most of the organic pollutants in the water body are removed, and the water quality is significantly improved.

[0034] Reference Figure 1 , the ecological purification unit 4 is used to further treat the tail water treated by the adsorption and filtration unit 3, and its inlet water comes from the water discharged from the lowest water purification area 33 of the adsorption pool 31. In this embodiment, the ecological purification unit 4 includes an ecological pool 41, in which aquatic plants 43 are planted and an algae biological carrier 42 and an oxygen dissolver are provided. The aquatic plants 43 are submerged plants and / or emergent plants, which have a fixation and purification effect on a small amount of pollutants remaining in the water body. The ecological pool 41 can be adapted to local conditions and transformed by using existing small ponds, ditches, depressions, etc. The aquatic plants 43 are preferably native plants, which can be reeds, lotus, water onion, cattail, calamus and loosestrife. The oxygen dissolver is used to increase the dissolved oxygen content of the water body; the algae biological carrier 42 is used for algae to attach and grow, and the attached algae can also perform biological filtration on the water body, reduce pollution in external water, reduce turbidity, and improve water quality. The algae put in can be pink green foxtail algae, elodea, black algae and goldfish algae. The water quality of the water body is relatively stable after the adsorption treatment, so the ecological purification unit 4 can operate stably. The water quality of the water body after ecological purification is closer to the water quality of natural water bodies, and has less impact on the receiving water body after discharge.

[0035] Reference Figure 1The drainage pool 5 is used to cache the water purified by the ecological purification unit 4. When the purified water needs to be discharged or further utilized, water can be taken from the drainage pool 5.

[0036] [Example 2]

[0037] Embodiment 2 is based on Embodiment 1, except that:

[0038] Reference Figure 7 and Figure 8 , the bottom edge of the adsorption brick 34 is rounded and chamfered. In order to further increase the assembly stability of the adsorption brick 34, a pair of support arms 86 are provided on the mounting ring 8, and the same pair of support arms 86 are symmetrically distributed on both sides of the central axis of the mounting ring 8. The support arm 86 consists of three parts: a connecting section 861, an arc section 862 and a straight section 863. Among them, the connecting section 861 is used to connect with the mounting ring 8, the arc section 862 is used to connect the straight section 863 and the connecting section 861, which can fit with the edge of the mounting groove 3411, and the straight section 863 is located at the end of the arc section 862 for fitting the bottom surface of the adsorption brick 34. The support arm 86 can be made of metal or a plastic material with sufficient strength, and has a certain deformation ability. When the adsorption brick 34 is installed, it fits with the bottom surface of the adsorption brick 34 through the arc section 862 and the straight section 863 to play a supporting role. Under the joint action of the support arm 86 and the resistance member, the stability of the adsorption brick 34 can be maintained.

[0039] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A water treatment plant tailwater ecological purification system, comprising a tailwater pool (1), a sedimentation purification unit (2), an adsorption filtration unit (3), an ecological purification unit (4) and a drainage pool (5) connected in sequence, characterized in that: The adsorption filtration unit (3) is used to absorb and intercept pollutants in tail water that has been purified by sedimentation, and comprises an adsorption pool (31) and a plurality of adsorption layers (32) arranged at intervals in the adsorption pool (31), wherein the adsorption layers (32) divide the space in the adsorption pool (31) into a plurality of clean water areas (33); the adsorption layer (32) comprises a plurality of hollow adsorption bricks (34) made of permeable concrete and arranged in a rectangular array, wherein the inner cavity of the adsorption bricks (34) is filled with adsorption filter material (38); A plurality of parallel backwash pipes (35) are provided below each adsorption layer (32), and a plurality of through holes are provided on the backwash pipe (35) facing the bottom surface of the adsorption brick (34); a mounting groove (3411) for the backwash pipe (35) to be inserted is provided on the bottom surface of the adsorption brick (34); one end of the backwash pipe (35) is connected to a water inlet pipe (36), and the water inlet pipe (36) is used to supply water from the clean water area (33) where the backwash pipe (35) connected thereto is located to the backwash pipe (35); the other end of the backwash pipe (35) is connected to a water return pipe (37), and the water return pipe (37) is used to return water from the clean water area (33) where the backwash pipe (35) connected thereto is located to the clean water area (33) of the upper layer; the water inlet pipe (36) is connected to a water pump (361), and the water return pipe (37) is installed with a control valve (371) that can be intermittently closed.

2. The water treatment plant tail water ecological purification system according to claim 1, characterized in that: The adsorption brick (34) comprises a brick body (341) and a cover body (342); the four corners of the bottom surface of the cover body (342) are provided with a clamping block (3421); the four corners of the top surface of the brick body (341) are provided with a clamping groove (3412) for the clamping block (3421) to be clamped into.

3. The water treatment plant tail water ecological purification system according to claim 2, characterized in that: The adsorption filter material (38) comprises an activated carbon adsorption layer (381) filled in the inner cavity of the brick body (341) from bottom to top, and a density of 100-150 kg / m 3 The expanded granite layer (382), the expanded ceramsite layer (383) and the quartz sand layer (384) are provided.

4. The water treatment plant tail water ecological purification system according to claim 3, characterized in that: The filling volume ratio of the activated carbon adsorption layer (381), the expanded granite layer (382), the expanded ceramsite layer (383) and the quartz sand layer (384) is 1:1.5:2:

3.

5. A water treatment plant tail water ecological purification system according to any one of claims 1 to 4, characterized in that: The backwash pipe (35) is sleeved with a plurality of mounting rings (8), and the mounting rings (8) are provided with a plurality of abutment members distributed at intervals along the circumferential direction, and the abutment members abut against the side walls of the mounting groove (3411) so that the pipe wall of the backwash pipe (35) does not contact the mounting groove (3411).

6. The water treatment plant tail water ecological purification system according to claim 5, characterized in that: The abutment member comprises an insertion tube (81) fixed to the mounting ring (8), an insertion rod (82) inserted into the insertion tube (81), and an abutment block (83) fixed to the end of the insertion rod (82); the insertion tube (81) is arranged radially along the mounting ring (8), and an elastic member (84) capable of generating an axial elastic force along the insertion tube (81) is provided inside the insertion tube (81), and an anti-detachment member (85) for preventing the insertion rod (82) from detaching from the insertion tube (81) is provided at the tube mouth; the abutment block (83) has an abutment arc surface (831) adapted to the arc of the groove wall of the mounting groove (3411).

7. A water treatment plant tail water ecological purification system according to any one of claims 1 to 4, characterized in that: The ecological purification unit (4) is used to purify water discharged from the lowest water purification area (33) of the adsorption pool (31), and comprises an ecological pool (41) in which aquatic plants (43) are planted, and an algae biological carrier (42) and an oxygen dissolver are provided.

8. The water treatment plant tail water ecological purification system according to claim 7, characterized in that: The aquatic plants (43) are submerged plants and / or emergent plants.

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