CN106865672A - A kind of mechanical stirring copolymerizing and air-float coupled double-layer horizontal sedimentation tank water cleaning systems and method - Google Patents

Abstract

The invention relates to a water purification system and method of a mechanically stirred copolymerized air flotation coupled double-layer advection sedimentation tank. The organic combination of dissolved air flotation and double-layer advection sedimentation tank forms a new floating and sinking tank. The copolymerization air flotation process organically combines mechanical flocculation and dissolved air flotation to form copolymerized dissolved air flotation, which strengthens the stability of foam flocs. The organic combination of air flotation and ozone oxidation makes full contact with water pollutants, greatly enhancing the effect of ozone oxidation. The organic combination of mechanical flocculation, copolymerization air flotation and double-layer advection sedimentation forms stable foam flocs under the conditions of convenient operation, effective control of speed, and reduction of water loss. The process of the invention has a flexible operation mode, can effectively reduce operating costs, has the advantages of strong adaptability to water quality changes, simple structure, high efficiency, convenient operation, and the like, and has broad application prospects.

Description

A mechanical stirring type copolymerization air flotation coupling double-layer advection sedimentation tank water purification system and its method

technical field

The invention belongs to the technical field of air flotation water treatment, and relates to a copolymerization air flotation coupling advection sedimentation water purification process and method, in particular to a mechanical stirring type copolymerization air flotation coupling double layer advection sedimentation tank water purification system and method.

Background technique

At present, the problem of reservoir water pollution is becoming more and more serious, among which algae pollution is the most serious. At present, the reservoir water tends to show the characteristics of high algae and high organic matter in summer and low temperature and low turbidity in winter. As the degree of eutrophication in the water body increases year by year, the rate of algae proliferation is increasing. Especially in spring and autumn when the temperature changes greatly, algae outbreaks occur from time to time, which poses a great threat to the operation of water plants and the safety of water supply. . The density of algae is small, and the traditional coagulation, sedimentation, and filtration processes are not only difficult to effectively remove it, but also bring a series of problems such as filter blockage, shortened backwash cycle, increased treatment cost, and poor effluent quality. Certain algae can also produce algal toxins under certain circumstances, posing a threat to water supply security. At the same time, the algae outbreak will inevitably lead to a decrease in the dissolved oxygen content in the raw water, and the death of aquatic organisms will lead to an increase in the organic matter content in the water body. The increase in the phenomenon of high organic matter content in raw water will bring a series of problems such as high difficulty in treatment and increased operation and treatment costs, which makes the removal of organic matter in water become an important issue.

As an efficient and fast solid-liquid separation technology, the traditional air flotation process has been promoted in the field of water treatment, and has been widely used in the purification of low-temperature, low-turbidity and algae-rich water bodies. However, there are still some disadvantages in the traditional air flotation technology: 1) The traditional air flotation technology adopts the method of one-time reflux of dissolved air water. Contact lag, short contact time, and the copolymerization of microbubbles and flocs cannot be fully exerted during the water purification process, the adhesion efficiency of microbubbles and flocs is not high, and the effective utilization rate of microbubbles is low; 2) Traditional air flotation The technology can only adhere to the suspended particles, form flocs with a specific gravity smaller than water and make them float, but it does not effectively remove some organic matter in the water, especially dissolved organic matter.

In the traditional dissolved air flotation process, micro-bubbles and floc particles adhere in water mainly according to the collision adhesion mechanism. There are three sub-processes in the collision adhesion process between bubbles and floc particles: (1) Collision process , the distance between the two is gradually reduced to meet; (2) Adhesion process, the thickness of the liquid film between the two is thinned to rupture, and finally a stable three-phase contact angle is formed; (3) Desorption process, bubble flocs For the re-separation of the combination, if the shear kinetic energy (or other forms of disturbance energy) exceeds the adhesion energy, the bubbles and particles will be separated again. The actual consumption of pressurized dissolved air water in the traditional dissolved air flotation process is much higher than the theoretical consumption of pressurized dissolved air water determined according to the concentration of solid particles in the water. Therefore, the traditional dissolved air flotation process still has a lot of room for optimization in terms of the contact chamber structure, water flow characteristics, and foam and floc adhesion methods, which can further improve the foam and floc adhesion efficiency.

At the same time, the traditional dissolved air flotation process only introduces air to produce ordinary air microbubbles. Although it has achieved some good results in the treatment of low-temperature, low-turbidity, and high-algae water bodies, compared with water bodies with high organic matter However, the treatment effect is not very obvious, especially in the treatment of water bodies with high concentrations of soluble organic matter, with little effect. At present, due to the impact of human activities, the content of organic matter in the water body is also increasing. Can the traditional air flotation process be improved to remove high algae and organic matter in the water body in an effective way? At this stage, the operation of the water plant will be of great significance.

Contents of the invention

Aiming at the current characteristics of reservoir water with high algae and organic matter in summer and low temperature and low turbidity in winter, the present invention independently develops a new air flotation sedimentation tank process, and improves the traditional dissolved air flotation process. The combination of sedimentation and air flotation process adds ozone to the traditional air flotation device to form ozonated dissolved air flotation, which can make the method of the present invention remove high algae while using the strong oxidation of ozone and its coagulation aiding effect, Effective removal of odor and other substances in the water body can also strengthen the removal of dissolved organic matter by the process. The invention organically combines enhanced coagulation, copolymerization air flotation, double-layer advection precipitation, ozone oxidation and other processes together and integrates them, and has outstanding advantages in dealing with high algae, high organic matter, low turbidity and other aspects of reservoir water quality.

Technical scheme of the present invention is as follows:

A mechanical agitation type copolymerization air flotation coupling double-layer advection sedimentation tank water purification system, including a three-stage mechanical agitation copolymerization flocculation tank, an air flotation contact tank, a double-layer advection sedimentation tank, an ozonated dissolved air flotation device and a release device;

(1) The three-stage mechanical stirring coagulation flocculation tank includes three coagulation chambers, which are coagulation 1 chamber, coagulation 2 chamber and coagulation 3 chamber, each coagulation chamber is equipped with 1 to 2 mechanical shafts , the coagulation chamber 1 is connected with a water inlet pipe;

(2) The air flotation contact pool includes an air flotation contact area, scum scraping equipment and a scum removal tank for collecting scum on the pool wall; the scum scraping equipment includes The slideway on the upper part of the pool body and the scraper reciprocating on the water surface along the slideway;

(3) The double-layer advection sedimentation tank includes water inlet perforated flower wall, sludge discharge pipe, sludge hopper, lower sedimentation area, baffle plate, upper sedimentation area, scum removal tank, outflow channel, slag scraping equipment, Mud scraping driving, the water outlet pipe is laid around the wall of the pool in the upper sedimentation area; an intermediate partition wall is set between the upper sedimentation area and the lower sedimentation area, and the baffle is located in the upper sedimentation area, and is set to separate the upper sedimentation area. area and the end of the intermediate partition wall of the lower sedimentation area; the scum removal tank is constructed adjacent to the outflow channel; the mud scraping vehicle is provided with a slideway according to the wall of the upper sedimentation area, and the lower end of the scraper of the mud scraping vehicle is set in the middle The layer partition wall can reciprocate along the slideway; the slag scraping equipment includes a slideway and a scraper, the slideway is laid above the pool body in the upper sedimentation area, and the scraper can reciprocate along the slideway on the water surface The water inlet perforated flower wall is arranged in the front section of the lower sedimentation area, and is connected with the air flotation contact tank; the sludge bucket is arranged at the bottom of the lower sedimentation area, and is connected with a sludge discharge pipe;

(4) The ozonation dissolved air flotation device includes a return water pump, the inlet end of the return water pump is connected to the outlet pipe of the double-layer advection sedimentation tank, and the outlet end is connected to a pressure vessel tank; the pressure vessel tank An air compressor and an ozone generator are respectively connected through pipelines with valves;

(5) The release device includes a return pipe and a dissolved air releaser, and the dissolved air releaser is respectively arranged at the bottom of the coagulation 2 chamber, the air flotation contact tank and the lower sedimentation area, and the return pipe and the dissolved air releaser pass through The three-way pipe is connected; the initial end of the return pipe is connected to the pressure vessel tank, and is provided with a control valve.

Preferably, the coagulation chamber 1 is provided with two mechanical shafts to ensure the coagulation effect.

The installation of the mechanical shaft should comply with the following requirements: the top of the impeller paddle on the uppermost layer should be set at 0.5m below the water surface of the pool; The distance between the edge and the pool wall is not more than 0.25m.

Further, in order to ensure a better water outlet effect, the double-layer advection sedimentation tank has an aspect ratio of 4:1 and a length-to-water depth ratio of 10:1.

Preferably, in order to ensure the floating of the foam flocs and the discharge of the bottom mud, the partition wall of the middle layer is designed with an upward slope of 5‰.

Preferably, the pressure vessel tank is used for preparing dissolved air water, and the dissolved air pressure is 0.30-0.45Mpa.

Preferably, a valve is provided on the connecting pipeline between the return water pump and the pressure vessel tank, and a valve is provided on the connecting pipeline between the pressure vessel tank, the air compressor and the ozone generator.

The dissolved air releaser is in the coagulation 2 room, the air flotation contact tank and the lower sedimentation area, and the ratio of releasing dissolved air to water is 1:2:4.

The three-pole mechanical stirring copolymerization flocculation tank, the air flotation contact tank, and the double-layer advection sedimentation tank are connected in sequence; the ozonated dissolved air flotation device is arranged outside the tank, and the high-pressure dissolved air water is delivered to the release device through the return pipe. Realize the release of dissolved air.

The three-pole mechanical stirring copolymerization flocculation tank and the air flotation contact tank control the flow of water through the wall between the two tanks; the double-layer advection sedimentation tank uses water through the perforated flower wall cloth provided on the lower layer of the sedimentation tank.

The water inlet pipe is connected with a dosing pipe, and is connected to the lower front end of the three-stage mechanical stirring copolymerization flocculation tank.

A water purification method of copolymerization air flotation coupling advection sedimentation, using the above water purification system, the steps include:

1) The raw water enters the three-stage mechanical agitation copolymerization flocculation tank from the lower end of the coagulation 1 chamber body through the water inlet pipe, and at the same time, the flocculant is added with the raw water through the dosing pipe, and the water flow sequentially passes through the three coagulation chambers of the copolymerization mechanical flocculation tank. Fully coagulate under the action of the mechanical shaft, and pass through the baffles set between each coagulation chamber to prevent short-flow of incoming water and ensure sufficient coagulation. At the same time, the dissolved air release device releases dissolved air into the coagulation chamber At the same time, ozone is released to ozonize the water flow and play a role in coagulation;

2) Step 1) After the raw water is processed, part of the water flows into the pressure vessel tank through the return pump, and at the same time, air and ozone are pressed into the pressure vessel tank under the action of the air compressor and ozone generator to form high-pressure ozonated dissolved air The water flows back to the coagulation chamber 2, the air flotation contact tank and the right end of the lower sedimentation area respectively through the return pipe and the dissolved air releaser. The high-pressure ozonated dissolved air water undergoes reverse collision and copolymerization, and the microbubbles participate in the coagulation process and the flocs copolymerize and grow;

3) Foam flocs are formed after copolymerization, and enter the lower sedimentation area through the water inlet perforated flower wall with the water flow, and adhere to the right end of the lower sedimentation area in the same direction as the reflowing dissolved air water, and enter the upper sedimentation area through the baffle to realize foam flocs Separation from the water flow, part of the separated water flow is prepared by the return water pump to prepare high-pressure dissolved air water, and the remaining water flows out of the system through the outlet pipe;

4) The scum generated by the system is collected in the coagulation room 2, the air flotation contact tank and the upper sedimentation area through the scum scraping equipment and enters the scum removal tank for removal. For the settled flocs that cannot be air floated, they enter with the water flow The double-layer advection sedimentation tank, through the solid-liquid separation of the upper and lower layers, further removes the suspended solids in the water that are not easy to float, and the sludge in the lower sedimentation area is discharged by hydrostatic pressure method, and it settles into the sludge under the action of gravity. The sludge in the upper sedimentation area is collected into the sludge hopper by the scraper and discharged through the sludge discharge pipe.

In step 1), the linear velocity at the center of the mechanical rotating shaft and impeller paddle plate is 0.4-0.5m/s for the first row, 0.2-0.4m/s for the second row, and 0.1-0.2m/s for the last row. s, each line speed should be gradually reduced.

In step 3), the reflux ratio of the separated water flow through the reflux pump to prepare high-pressure dissolved air water is 10-20%, and the dissolved air pressure is 0.30-0.45Mpa.

In step 3), the water inlet perforated flower wall has the effect of uniform water distribution. In order to ensure the integrity of the foam and floc, the flow rate of the through holes is required to be less than 0.05m/s.

The innovation of the technical solution of the present invention and the traditional air flotation process lies in:

1) The present invention organically combines mechanical flocculation, copolymerized air flotation and double-layer advection sedimentation to form stable foam flocs under the conditions of convenient operation, effective control of rotational speed, and reduction of water loss. The air flotation contact chamber is divided into three stages, and the ozonated dissolved air water is added three times. In the coagulation chamber 2 and the air flotation contact tank, the raw water flows from top to bottom, and the microbubbles generated by the release device flow in reverse from bottom to top, relying on hydraulic mixing to complete the full collision of microbubbles and flocs, and the coagulation and transformation of flocs. big. On the right side of the lower sedimentation area, the dissolved air water and the raw water flow in the same direction, forming stable foam flocs and entering the upper sedimentation area through the baffle. The flocs in the water and the microbubbles collided twice and adhered once in sequence, which greatly improved the collision efficiency and adhesion efficiency of the microbubbles-suspended matter.

2) The present invention has invented a copolymerization air flotation process in which micro-bubbles directly participate in flocculation. During the growth process, flocs and micro-bubbles undergo collision adhesion and adhesive contact in sequence, which effectively prolongs the collision between flocs and micro-bubbles. The adhesion time significantly improves the microbubble-particle interaction, greatly enhances the stability of the bubble floc, and significantly enhances the microbubble-particle collision efficiency.

3) The copolymerized air flotation process of the present invention organically combines mechanical flocculation and dissolved air flotation to form copolymerized dissolved air flotation, which strengthens the stability of foam flocs. By optimizing the mechanical stirring coagulation system and the dissolved air flotation system, the dissolved air flotation is added three times, the dissolved air water reflux ratio is 10%-20%, and the high-pressure dissolved air water is refluxed to the coagulation room 2, and the air flotation contact The ratio of the zone and the bottom end of the advection sedimentation tank is 1:2:4. In the coagulation chamber 2, the microbubbles are in reverse contact with the coagulation. The microbubbles directly participate in the flocculation and co-polymerize with flocs. The copolymerization effect is significantly enhanced when it is in full collision contact with the foam flocs again. The bubbles are wrapped in the middle of the flocs, which fully exerts the coagulation effect of the bubbles. The micro-bubbles are sandwiched between the flocs and are not easy to desorb. , so the copolymerization strengthens the stability of the foam flocs.

4) The present invention organically combines dissolved air flotation and double-layer advection sedimentation tanks to form a new type of floating-sinking tank. Firstly, the copolymerized air floating bubble floc formed by reverse collision passes through the perforated flower wall and enters the bottom layer of the advection sedimentation tank. After the suspended particles that are not easy to settle are further adhered to the microbubbles, they enter the upper advection sedimentation tank, which strengthens the air flotation effect. Compared with the traditional advection sedimentation tank, the double-layer advection sedimentation tank of this design is organically combined with the dissolved air flotation, which fully exerts the solid-liquid separation effect of the sedimentation tank and the air flotation tank, and can effectively improve the treatment efficiency while reducing the hydraulic retention time , thereby reducing the footprint of the sedimentation tank.

5) The floating-sinking tank process of the present invention has a flexible operation mode and significantly enhanced adaptability to changes in raw water quality. Air flotation and sedimentation carry out synergistic solid-liquid separation. When the concentration of algae in the raw water is high, the air flotation process is started. When the concentration of algae in the raw water is low or the sediment content is high, the air flotation can be stopped and the double-layer advection sedimentation tank process is run, so it can effectively reduce Operating costs, and, because the air flotation unit starts quickly and allows intermittent operation, it is relatively easy to switch between the two operating modes. By choosing different operation modes, the flexible switch between the air flotation unit and the advection sedimentation unit is realized, which strengthens the ability of the process to deal with the risk of water quality changes, and has the advantages of strong adaptability to water quality changes, simple structure, high efficiency, and convenient operation. application prospects.

6) The present invention organically combines air flotation and ozone oxidation, and the size of most of the microbubbles is 30-100 μm. The ozonated air utilizes the huge specific surface area of microbubbles to fully contact with pollutants in water, greatly enhancing the effect of ozone oxidation . ① Ozone has a strong coagulation-assisting effect. Microbubbles containing ozone are introduced into the mechanical flocculation tank, and under the principle of polymer adsorption bridging, the flocculation effect of the mechanical flocculation tank can be enhanced and the copolymerization can be strengthened. ②Ozone has strong oxidizing properties, and the microbubbles can stimulate a large number of hydroxyl radicals at the moment of rupture, which can strengthen the decomposition ability of ozone for organic matter, and can oxidize organic substances such as odors in water, especially effectively strengthen dissolved organic matter in water Removal, ozone in raw water treatment and copolymerization air flotation complement each other. While strengthening the ability of air flotation to remove algae, it is also embedded in the floc in the form of micro-bubbles, which increases the contact area and greatly enhances its oxidation capacity. Effluent water quality.

Description of drawings

Fig. 1 is the schematic diagram of the water purification system device of mechanical agitation type copolymerization air flotation coupled double layer advection sedimentation tank of the present invention;

In the figure: 1. Water inlet pipe, 2. Dosing pipe, 3. Mechanical shaft, 4. Coagulation room 1, 5. Coagulation room 2, 6. Coagulation room 3, 7. Air flotation contact tank, 8. Inlet Water perforated flower wall, 9, mud discharge pipe, 10, sludge hopper, 11, lower sedimentation area, 12, baffle, 13, upper sedimentation area, 14, scum removal tank, 15, outflow channel, 16, slag scraping equipment , 17, mud scraper driving, 18, return water pump, 19, air compressor, 20, ozone generator, 21, pressure dissolved gas tank, 22, container releaser, 3, return pipe, 24, outlet pipe.

detailed description

The technical solutions of the present invention will be further described below according to the drawings and embodiments.

Example 1

A mechanical agitation type copolymerization air flotation coupling double-layer advection sedimentation tank water purification system for treating ordinary reservoir water. The connected processing system is externally connected to the ozonated dissolved air flotation device and the release device, as shown in Figure 1:

(1) Three-stage mechanical stirring copolymerization flocculation tank, including three coagulation chambers, which are coagulation 1 chamber 4, coagulation 2 chamber 5 and coagulation 3 chamber 6, coagulation 1 chamber 4 is equipped with two mechanical shafts 3 Coagulation 2 chamber 5 and coagulation 3 chamber 6 are equipped with a mechanical shaft 3, coagulation 1 chamber 4 is connected with water inlet pipe 1; water inlet pipe 1 is connected with dosing pipe 2, and is in the third-stage mechanical stirring copolymerization flocculation tank access at the lower front end. The installation of the mechanical shaft 3 should follow the following requirements: the top of the impeller paddle on the uppermost layer should be set at 0.5m below the water surface of the pool; The distance from the pool wall is not more than 0.25m.

(2) Air flotation contact pool, including air flotation contact area 7, scum scraping equipment 16 and scum removal tank 14 for collecting scum arranged on the pool wall; scum scraping equipment 16 includes The slideway on the upper part of the pool body and the scraper reciprocating on the water surface along the slideway;

(3) Double-layer advection sedimentation tank, including water inlet perforated flower wall 8, sludge discharge pipe 9, sludge bucket 10, lower sedimentation area 11, baffle 12, upper sedimentation area 13, scum removal tank 14, outflow channel 15. Slag scraping equipment 16, mud scraping truck 17, outlet pipe 24 is laid along the upper sedimentation area 13 pool body around the wall; double-layer advection sedimentation tank, the aspect ratio is 4:1, and the length to water depth ratio is 10:1. An intermediate partition wall is set between the upper sedimentation zone 13 and the lower sedimentation zone 11. In order to ensure the floating of foam flocs and the discharge of bottom mud, the intermediate partition wall adopts an upward slope design of 5‰. The baffle 12 is located in the upper sedimentation zone 13, and is arranged at the end of the middle partition wall separating the upper sedimentation zone 13 and the lower sedimentation zone 11; the scum removal tank 14 is constructed adjacent to the outflow channel 15. The mud-scraping vehicle 17 is provided with a slideway according to the wall of the upper sedimentation area 13, and the scraper lower end of the mud-scraping vehicle 17 is arranged at the middle layer partition wall and can reciprocate along the slideway. Slag scraping equipment 16 includes a slideway and a scraper, the slideway is laid above the pool body of the upper sedimentation zone 13, and the scraper can reciprocate on the water surface along the slideway. The water inlet perforated flower wall 8 is arranged in the front section of the lower sedimentation area 11, and is connected with the air flotation contact pool. The sludge hopper 10 is arranged at the bottom of the lower sedimentation zone 11 and is connected with a sludge discharge pipe 9 .

(4) The ozonation dissolved air flotation device includes a return water pump 18, the inlet end of the return water pump 18 is connected to the outlet pipe 24 of the double layer advection sedimentation tank, and the outlet end is connected to the pressure vessel tank 21, the pressure vessel tank 21 is used to prepare dissolved air water, and the dissolved air pressure is 0.30-0.45Mpa. The pressure vessel tank 21 is respectively connected with an air compressor 19 and an ozone generator 20 through a pipeline provided with a valve. A valve is provided on the connection pipeline between the backflow pump 18 and the pressure vessel tank 21, and a valve is provided on the connection pipeline between the pressure vessel tank 21, the air compressor 19 and the ozone generator 20.

(5) The release device, including the return pipe 23 and the dissolved air releaser 22, the dissolved air releaser is respectively arranged at the bottom of the coagulation 2 chamber 5, the air flotation contact tank 7 and the lower sedimentation area 11, and the dissolved air releaser is in the coagulation In room 5, air flotation contact tank 7 and lower sedimentation area 11, the ratio of released dissolved air to water is 1:2:4. The return pipe 23 is connected to the dissolved air releaser 22 through a three-way pipe fitting; the initial end of the return pipe 23 is connected to the pressure vessel tank 21 and is provided with a control valve.

The three-pole mechanical stirring copolymerization flocculation tank, the air flotation contact tank 7, and the double-layer advection sedimentation tank are connected in sequence; the ozonated dissolved air flotation device is arranged outside the tank, and the high-pressure dissolved air water is delivered to the release device through the return pipe to realize Dissolved air is released; the water flow direction is controlled through the wall between the two pools between the three-pole mechanical stirring copolymerization flocculation tank and the air flotation contact tank 7; the double-layer advection sedimentation tank distributes water through the water inlet perforated flower wall 8 set on the lower layer of the sedimentation tank .

Example 2

A method for processing common reservoir water using the mechanically agitated copolymerized air flotation coupled double-layer advection sedimentation tank water purification system of Embodiment 1, that is, a method for copolymerizing air flotation coupled advection sedimentation water purification, specifically comprising the following steps:

1) The raw water enters the three-stage mechanical agitation copolymerization flocculation tank from the lower end of the coagulation 1 chamber 4 pool body through the water inlet pipe 1, and at the same time, the flocculant is added with the raw water through the dosing pipe 2, and the water flows through the three coagulation tanks of the copolymerization mechanical flocculation tank in turn. The coagulation chamber is fully coagulated under the action of the mechanical shaft 3, and through the baffles set between each coagulation chamber, it prevents the short flow of incoming water and ensures sufficient coagulation. Dissolved air water is released in chamber 5, and ozone is released at the same time to ozonize the water flow, which acts as a coagulation aid; the mechanical shaft 3, the linear velocity at the center of the impeller paddle plate, the first row adopts 0.4 ~ 0.5m/s, the second row Use 0.2~0.4m/s, the last row uses 0.1~0.2m/s, and the speed of each row should be gradually reduced.

2) The treated raw water in step 1, a part of the water flows into the pressure vessel tank 21 through the return water pump 18, and at the same time, air and ozone are pressed into the pressure vessel tank 21 under the action of the air compressor 19 and the ozone generator 20 to form The high-pressure ozonated dissolved air water flows back to the coagulation 2 chamber 5, the air flotation contact tank 7 and the right end 11 of the lower sedimentation area through the return pipe 23 and the dissolved air releaser 22, respectively. In the process, the flocs contained in the raw water flow in the pool collide with the returning high-pressure ozonated dissolved air water in reverse, and copolymerization occurs, and the microbubbles participate in the coagulation process and the flocs copolymerize and grow.

3) Foam flocs are formed after copolymerization, and enter the lower sedimentation zone 11 through the water inlet perforated flower wall 8 with the water flow, and adhere to the right end of the lower sedimentation zone 11 to flow in the same direction as the reflux dissolved air water, and enter the upper sedimentation zone 13 through the baffle 12 , to realize the separation of foam flocs and water flow, part of the separated water flow is prepared through the return water pump 18 to prepare high-pressure dissolved air water, and the remaining water flow flows out of the system through the outlet pipe 24.

The separated water flows through the reflux pump 18 to prepare high-pressure dissolved air water with a reflux ratio of 10-20% and a dissolved air pressure of 0.30-0.45Mpa. The water inlet perforated flower wall 8 has the effect of uniform water distribution. In order to ensure the integrity of the foam and floc, the flow rate of the through holes is less than 0.05m/s.

4) The scum generated by the system is collected in the coagulation 2 chamber 5, the air flotation contact tank 7 and the upper sedimentation area 13 via the slag scraping device 16 and entered into the scum removal tank 14 for removal. body, enters the double-layer advection sedimentation tank with the water flow, and through the solid-liquid separation of the upper and lower layers, the suspended solids in the water that are not easy to float are further removed. The sludge in the lower sedimentation area 11 is discharged by the hydrostatic pressure method. Under the action, it settles into the sludge hopper 10 and is discharged through the sludge discharge pipe 9; the sludge in the upper sedimentation area is collected into the sludge hopper 10 through the scraper 17 and discharged through the sludge discharge pipe 9.

Present embodiment 2 reservoir water is under different water quality conditions, and operating effect is as follows:

(1) During the high algae season in summer, the algae content is 3.0×10 ⁸ /L, and the turbidity is 5-80 NTU. The water after the above treatment has a total algae content of 5.0×10 ⁴ /L and a turbidity of 0.5 NTU.

(2) In winter, the water quality is characterized by low temperature and low turbidity, with an algae content of 4.0×10 ⁶ /L and a turbidity of 2-10 NTU. Use the above equipment for flocculation and air flotation. The algae content in the effluent is 1.0×10 ⁴ /L, and the turbidity is 0.6 NTU.

(3) During the summer rainy season, the water quality is characterized by high turbidity, with an algae content of 5.0×10 ⁷ /L and a turbidity of 100-150 NTU. The water after the above treatment has a total algae content of 6.0×10 ⁴ /L and a turbidity of 1.50 NTU.

Comparative example 1

Through the combination of traditional dissolved air flotation and sedimentation tank, the reservoir water in Example 2 is treated, and the effluent effect is as follows:

(1) During the high algae season in summer, the algae content is about 3.0×10 ⁸ /L, and the turbidity is 5-80 NTU. The water treated by traditional dissolved air flotation and advection sedimentation tank has a total algae content of 8.0×10 ⁵ /L and a turbidity of about 1.0 NTU.

(2) In winter, the water quality is characterized by low temperature and low turbidity, with an algae content of about 4.0×10 ⁶ /L and a turbidity of 2-10 NTU. The traditional dissolved air flotation and advection sedimentation tanks are used for flocculation and air flotation. The effluent contains about 7.0×10 ⁵ algae/L, and the turbidity is about 1.0 NTU.

(3) During the summer rainy season, the water quality is characterized by high turbidity, the algae content is about 5.0×10 ⁷ /L, and the turbidity is 100-150 NTU. The water after the above treatment has a total algae content of about 8.0×10 ⁵ /L and a turbidity of about 3.00 NTU.

Claims (10)

1. A mechanical agitation type copolymerization air flotation coupled double-layer advection sedimentation tank water purification system is characterized in that: it includes a three-stage mechanical agitation copolymerization flocculation tank, an air flotation contact tank, a double-layer advection sedimentation tank, an ozonated air-dissolved buoyancy and release devices; (1) The three-stage mechanical agitation copolymerization flocculation tank includes three coagulation chambers, which are coagulation 1 chamber (4), coagulation 2 chamber (5) and coagulation 3 chamber (6), each coagulation There are 1 to 2 mechanical shafts (3) in the room, and the coagulation room 1 (4) is connected with a water inlet pipe (1); (2) The air flotation contact pool includes an air flotation contact area (7), a scum scraping device (16) and a scum removal tank (14) for collecting scum arranged on the pool wall; the scraping scum Equipment, including the slideway laid on the upper part of the pool body in the air flotation contact area (7) and the scraper that reciprocates on the water surface along the slideway; (3) The double-layer advection sedimentation tank includes water inlet perforated flower wall (8), sludge discharge pipe (9), sludge bucket (10), lower sedimentation area (11), baffle plate (12), upper layer Sedimentation area (13), scum removal tank (14), outflow channel (15), slag scraping equipment (16), mud scraping vehicle (17), and outlet pipes ( 24); an intermediate partition wall is set between the upper sedimentation area (13) and the lower sedimentation area (11), and the baffle (12) is located in the upper sedimentation area (13) and is set to separate the upper sedimentation area ( 13) and the end of the intermediate partition wall of the lower sedimentation area (11); the scum removal tank (14) is constructed adjacent to the outflow channel (15); the mud scraping vehicle (17) follows the upper sedimentation area (13) The wall is equipped with a slideway, and the lower end of the scraper of the mud scraping vehicle (17) is set at the partition wall of the middle layer and can reciprocate along the slideway; the slag scraping device (16) includes a slideway and a scraper, and the slideway Laid above the pool body of the upper sedimentation area (13), the scraper can reciprocate along the slideway on the water surface; the water inlet perforated flower wall (8) is set in the front section of the lower sedimentation area (11), and is in contact with the air flotation The tanks are connected; the sludge bucket (10) is set at the bottom of the lower sedimentation area (11), and is connected with a sludge discharge pipe (9); (4) The ozonated dissolved air flotation device includes a return water pump (18), the inlet end of the return water pump is connected to the outlet pipe (24) of the double-layer advection sedimentation tank, and the outlet end is connected to a pressure vessel tank (21); the pressure vessel tank (21) is respectively connected to an air compressor (19) and an ozone generator (20) through a pipeline provided with a valve; (5) The release device includes a return pipe (23) and a dissolved air releaser (22), and the dissolved air releaser is respectively set in the coagulation 2 chamber (5), the air flotation contact tank (7) and the lower sedimentation At the bottom of the area (11), the return pipe (23) is connected to the dissolved air releaser (22) through a three-way fitting; the initial end of the return pipe (23) is connected to the pressure vessel tank (21), and a control valve is provided . 2. The water purification system according to claim 1, characterized in that: the first coagulation chamber (4) is provided with two mechanical shafts (3) to ensure the coagulation effect; the mechanical shaft (3) The installation should follow the following requirements: the top of the upper impeller paddle should be set at 0.5m below the water surface of the pool, the bottom of the bottom impeller paddle should be set at 0.5-1.0m from the bottom of the pool, and the distance between the outer edge of the paddle and the pool wall Not greater than 0.25m. 3. The water purification system according to claim 1, characterized in that: the double-layer advection sedimentation tank has an aspect ratio of 4:1, and a length-to-water depth ratio of 10:1; the middle layer partition wall adopts an upward 5‰ slope design. 4. The water purification system according to claim 1, characterized in that: the pressure vessel tank (21) is used to prepare dissolved air water, and the dissolved air pressure is 0.30-0.45Mpa; the return water pump (18) and the pressure Valves are provided on the connecting pipelines between the container tanks (21), and valves are provided on the connecting pipelines between the pressure vessel tanks (21), the air compressor (19) and the ozone generator (20). 5. The water purification system according to claim 1, characterized in that: the dissolved air release device (22) is located in the coagulation 2 chamber (5), the air flotation contact tank (7) and the lower sedimentation area (11), The ratio of releasing dissolved air to water is 1:2:4. 6. The water purification system according to claim 1, characterized in that: the three-pole mechanical agitation copolymerization flocculation tank, the air flotation contact tank (7), and the double-layer advection sedimentation tank are connected in sequence; the ozonation dissolved air The air flotation device is installed outside the tank, and the high-pressure dissolved air water is sent to the release device through the return pipe to realize the release of dissolved air; the three-pole mechanical stirring copolymerization flocculation tank and the air flotation contact tank (7) pass through the wall between the two tanks The body controls the water flow direction; the double-layer advection sedimentation tank distributes water through the water inlet perforated flower wall (8) arranged on the lower layer of the sedimentation tank; the water inlet pipe (1) is connected with the dosing pipe (2), The lower part of the front end of the mechanical stirring copolymerization flocculation tank is connected. 7. A water purification method of copolymerization air flotation coupled advection sedimentation, using the water purification system described in any one of claims 1 to 6, characterized in that the steps include: 1) The raw water enters the three-stage mechanical stirring copolymerization flocculation tank from the lower end of the coagulation chamber 1 (4) through the water inlet pipe (1), and at the same time, the flocculant is added with the raw water through the dosing pipe (2), and the water flow sequentially passes through the copolymerization mechanical flocculation The three coagulation chambers of the pool are fully coagulated under the action of the mechanical shaft (3), and the baffles set between each coagulation chamber prevent short flow of incoming water and ensure sufficient coagulation. The dissolved air release device releases dissolved air water into the coagulation 2 chamber (5), and at the same time releases ozone to ozonize the water flow, which plays a coagulation aiding role; 2) The treated raw water in step 1, part of the water flow enters the pressure vessel tank (21) through the return water pump (18), and at the same time, the air and ozone are compressed under the action of the air compressor (19) and the ozone generator (20). into the pressure vessel tank (21) to form high-pressure ozonated dissolved air water, which flows back through the return pipe (23) and dissolved air releaser (22) to the coagulation 2 chamber (5), the air flotation contact tank (7) and At the right end of the lower sedimentation area (11), in the coagulation 2 chamber (5) and the air flotation contact tank (7), the flocs contained in the raw water flow in the pool collide with the returning high-pressure ozonated dissolved air water, and copolymerization occurs. Microbubbles participate in the coagulation process and the co-polymerization of flocs; 3) Foam flocs are formed after copolymerization, and enter the lower sedimentation area (11) through the water inlet perforated flower wall (8) with the water flow, and adhere to the right end of the lower sedimentation area (11) in the same direction as the returning dissolved air water, and pass through the baffle (12) Enter the upper sedimentation area (13) to realize the separation of the foam flocs and the water flow. Part of the separated water flow is prepared by the return water pump (18) to prepare high-pressure dissolved air water, and the remaining water flows out of the system through the outlet pipe (24); 4) The scum generated by the system is collected in the scum removal tank (14) via the scum scraping equipment (16) in the coagulation 2 chamber (5), the air flotation contact tank (7) and the upper sedimentation area (13). For the sedimentation flocs that cannot be air-floated, they enter the double-layer advection sedimentation tank with the water flow, and after the solid-liquid separation of the upper and lower layers, the suspended solids that are not easy to float in the water are further removed, and the sewage in the lower sedimentation area (11) The mud is discharged by hydrostatic pressure method, and it settles into the sludge hopper (10) under the action of gravity, and is discharged through the sludge discharge pipe (9); the sludge in the upper sedimentation area (13) is collected to the sewage by the scraper truck (17). In the mud hopper (10), it is discharged through the mud discharge pipe (9). 8. The method according to claim 7, characterized in that: in step 1), the linear velocity of the mechanical shaft (3), the center of the paddle plate of the impeller, is 0.4-0.5m/s for the first row, and 0.4-0.5m/s for the second row. The row adopts 0.2~0.4m/s, the last row adopts 0.1~0.2m/s, and the speed of each row should be gradually reduced. 9. The method according to claim 7, characterized in that: in step 3), the reflux ratio of the separated water flow through the reflux pump (18) to prepare high-pressure dissolved air water is 10-20%, and the dissolved air pressure 0.30～0.45Mpa. 10. The method according to claim 7, characterized in that: in step 3), the water inlet perforated flower wall (8) has the function of uniform water distribution, and in order to ensure the integrity of the foam floc, the flow rate of the through hole is required to be less than 0.05m/s.