CN116693106B - A wastewater treatment system based on dialysis-denitrification - Google Patents

Abstract

The present invention relates to the field of wastewater treatment, and specifically to a wastewater treatment system based on dialysis-denitrification, including a raw water pool, an alkali tank, an acid tank, and an alkali supplement pipe for supplementing strong alkali into the alkali tank, a Daonan dialysis assembly is provided between the raw water pool and the alkali tank, and a first pipeline is connected between the raw water pool and the Daonan dialysis assembly; an osmotic distillation assembly is provided between the alkali tank and the acid tank, a second pipeline is connected between the alkali tank, the Daonan dialysis assembly and the osmotic distillation assembly, and a third pipeline is connected between the acid tank and the osmotic distillation assembly; a stirring shaft is provided in the alkali tank, and a plurality of blades are fixed on the stirring shaft, and the blades are located inside the alkali tank. When the strong alkali solution is supplemented into the alkali tank, this scheme reduces the detection error of the pH detector, can enrich the ammonia nitrogen in the wastewater and then recycle it, so as to achieve the purpose of ammonia nitrogen resource utilization, and reduces the cost of recovering ammonia nitrogen, and solves the possibility of secondary pollution of secondary products.

Description

A wastewater treatment system based on dialysis-denitrification

Technical Field

The invention relates to the field of wastewater treatment, and in particular to a wastewater treatment system based on dialysis-denitrification.

Background Art

With the development of industry and agriculture and the improvement of people's living standards, the discharge of nitrogen-containing wastewater has increased dramatically. Since ammonia nitrogen has important utilization and economic value in agriculture and industry, it is very important to recover ammonia nitrogen from wastewater. At present, there are mainly the following methods to remove ammonia nitrogen from wastewater: biochemical method, ion exchange method, air stripping method and breakpoint chlorine method.

Among them, when using biochemical methods to treat ammonia nitrogen wastewater, the ammonia nitrogen concentration cannot be too high. The higher the ammonia nitrogen concentration in the sewage, the stronger the inhibitory effect on microbial activity. At present, the concentration of biological denitrification is generally below 400 mg/L. When the concentration is greater than 400 mg/L, the activity of microorganisms will be greatly inhibited, which is not conducive to the treatment of ammonia nitrogen.

The ion exchange method utilizes the strong selectivity of zeolite for NH ₄ ⁺ to retain NH ₄ ⁺ on the surface of zeolite, thereby removing ammonia nitrogen from wastewater. However, when the exchange capacity of zeolite is saturated, zeolite needs to be regenerated. Therefore, this method requires large investment and high processing cost, and is rarely used in engineering.

The breakpoint chlorination method has high requirements for the safe use and storage of liquid chlorine, and also has high requirements for pH value. The produced water needs to be neutralized with alkali, which has high treatment costs. In addition, residual chlorine, by-product chloramines and chlorinated organic matter can also cause secondary pollution.

During the stripping process, pH, water temperature, hydraulic load and gas-water ratio have a great influence on the stripping effect. Therefore, it is necessary to strictly control parameters such as pH, water temperature, hydraulic load and gas-water ratio, resulting in harsh conditions for wastewater treatment, high wastewater treatment costs and complex condition control.

In summary, the current treatment methods for ammonia nitrogen in wastewater have the following shortcomings: limited treatment limits for ammonia nitrogen, high treatment costs, large investments, and the possibility of secondary pollution.

Therefore, developing a wastewater treatment system with low energy consumption, high efficiency and sustainable recovery of ammonia nitrogen is an urgent problem to be solved.

Summary of the invention

The present invention is intended to provide a wastewater treatment system based on dialysis-denitrification, so as to design a wastewater treatment system with low energy consumption and low cost for ammonia nitrogen treatment and recovery.

To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a wastewater treatment system based on dialysis-denitrification, comprising a raw water tank, an alkali liquid tank, an acid liquid tank and an alkali liquid supplement pipe for supplementing strong alkali into the alkali liquid tank, a Daonan dialysis component is arranged between the raw water tank and the alkali liquid tank, and a first pipeline is connected between the raw water tank and the Daonan dialysis component; an osmotic distillation component is arranged between the alkali liquid tank and the acid liquid tank, a second pipeline is connected between the alkali liquid tank, the Daonan dialysis component and the osmotic distillation component, and the liquid in the alkali liquid tank enters the Daonan dialysis component and the osmotic distillation component in turn along the second pipeline and then returns to the alkali liquid tank; a third pipeline is connected between the acid liquid tank and the osmotic distillation component; pumps are arranged on the first pipeline, the second pipeline and the third pipeline; a stirring shaft is arranged in the alkali liquid tank, a plurality of blades are fixed on the stirring shaft, the blades are located inside the alkali liquid tank, and a driving mechanism for driving the stirring shaft to rotate is arranged on the outside of the alkali liquid tank.

The principle and advantage of this scheme are as follows: the wastewater in the raw water pool enters the Daonan dialysis component through the first pipeline, the alkali solution in the alkali tank enters the Daonan dialysis component through the second pipeline, the Daonan dialysis component is provided with a cation exchange membrane, the wastewater and the alkali solution are respectively located on both sides of the cation exchange membrane, the ammonium ions in the wastewater and the driving ions in the alkali solution are replaced across the cation exchange membrane under the action of concentration difference, and the ammonium ions react with the hydroxide ions in the alkali solution to generate ammonia. Then the ammonia in the Daonan dialysis component enters the osmotic distillation component along the second pipeline, the acid solution in the acid tank enters the osmotic distillation component through the third pipeline, the osmotic distillation component is provided with a breathable hydrophobic membrane, the alkali solution with ammonia and the acid are respectively located on both sides of the breathable hydrophobic membrane, the ammonia is mixed with the acid solution across the breathable hydrophobic membrane under the action of the pressure difference on both sides of the breathable hydrophobic membrane, the ammonia and the acid solution are mixed and enter the acid tank through the third pipeline, and the ammonia and the acid solution are mixed and converted into ammonium salts for subsequent recycling. Through this system, the entire process is driven by natural concentration difference, without the need for additional energy input, and can continuously reduce ammonia nitrogen in sewage, with high denitrification efficiency and stable operation. It can simultaneously achieve the removal and recovery of ammonia nitrogen in wastewater, and the coupled process has better treatment efficiency than the single process. In addition, the driving force in the system is driven by concentration difference (pressure difference), without the need for external energy, and is a low-energy, low-cost ammonia nitrogen treatment and recovery system. In addition, the entire system does not require complex operation and management, and is suitable for unmanned management mode and operation in remote areas.

The core idea of this scheme to recycle ammonia nitrogen is to add a new DD-OD technology to the system. This technology is based on membrane separation to enhance the migration and transformation process of different forms of nitrogen. First, the ammonia nitrogen is enriched from the ammonia nitrogen wastewater using Daonan dialysis with zero energy consumption to reduce the material consumption of subsequent treatment, and then the ammonia nitrogen is recovered by osmotic distillation with zero energy consumption. At the same time, osmotic distillation can increase the enrichment rate of ammonia nitrogen by Daonan dialysis. Finally, nitrogen is reused in the form of products, reflecting the concept of sustainable development. The ammonia nitrogen in the wastewater is recycled and treated by this system, which reduces the cost of recovering ammonia nitrogen, has a high recovery rate of ammonia nitrogen, low investment, and low secondary pollution.

In addition, as the alkali tank in the system is continuously used, the pH value in the alkali tank will change, so it is necessary to supplement strong alkali solution to maintain the alkaline environment in the alkali tank. For this reason, the inventor installed a pH detector on the inner wall of the alkali tank, and the pH value of the solution in the alkali tank was detected by the pH detector. When the pH value is lower than a certain value, the alkali is supplemented into the alkali tank through the alkali replenishment pipeline. However, the position of the strong alkali solution is fixed. After the strong alkali solution is supplemented into the alkali tank from one side of the alkali tank, the strong alkali solution will not be immediately mixed with the liquid in the alkali tank and dispersed. The strong alkali solution is slowly dispersed and mixed in the alkali tank, so that the pH detector has a certain delay error in the pH value detection, and the pH detector is inaccurate in the pH value detection, and the pH detector detection value will be lower than the actual value. When the pH detector detects that the pH value meets the requirements, a certain amount of strong alkali solution has been added to the alkali tank, which will cause the phenomenon of excessive addition of strong alkali solution. Since ionic ammonium-ammonia gas is distributed differently under different pH environments, the alkali liquid in the alkali liquid tank needs to enter the Daonan dialysis component and the osmotic distillation component to react. The pH value in the alkali liquid tank will affect the reaction in the two components. Therefore, the pH value detection and control in the alkali liquid tank is more important. Inaccurate pH value detection of the alkali liquid in the alkali liquid tank will affect the effect of the entire system on the recovery and treatment of ammonia nitrogen in wastewater.

Therefore, in this scheme, when the strong alkali solution is added to the alkali tank, the stirring shaft is driven to rotate by the driving mechanism, and the stirring shaft drives the blades to rotate, thereby stirring the alkali in the alkali tank, so that the strong alkali solution is added while stirring and mixing, so that the added strong alkali solution can be dispersed in the alkali tank more quickly, compared with the strong alkali solution naturally slowly dispersed in the alkali tank, so that the pH detector on the inner wall of the alkali tank can detect the change of pH value more quickly, reducing the delay of the detection of the pH detector, reducing the detection error of the pH detector to the pH value, making the pH detector to detect the pH value more accurately, and can more accurately control the pH value in the alkali tank, so that it is easier to accurately control the amount of strong alkali added. In this way, the pH value of the alkali in the alkali tank can be controlled more accurately, so that the ion ammonium-ammonia gas is in a more suitable pH value environment, ensuring the effect of the entire system on the recovery and treatment of ammonia nitrogen in wastewater.

In addition, even when the strong alkaline solution is not replenished, the stirring shaft can be in a state of continuous rotation, because the liquid in the alkali liquid tank continuously flows into the Daonan dialysis component and the osmotic distillation component, and liquid in the Daonan dialysis component and the osmotic distillation component continuously flows back to the alkali liquid tank. In this way, the liquid flowing back from the alkali liquid tank is stirred by the stirring shaft, so that the liquid in the alkali liquid tank can be continuously in a mixed and stirred state, thereby ensuring that the liquid composition entering the Daonan dialysis component and the osmotic distillation component from the alkali liquid tank is relatively uniform, thereby ensuring the effect of ammonia nitrogen treatment.

Preferably, as an improvement, the raw water pool is connected to a water collection pool, and a security filter is provided between the raw water pool and the water collection pool. Thus, the security filter can filter the liquid before entering the raw water pool to remove impurities in the water, thereby avoiding damage to the Donan dialysis component, the osmotic distillation component and the entire system.

Preferably, as an improvement, a clean water tank for cleaning the Donan dialysis assembly and the osmotic distillation assembly is further included. Thus, the clean water tank is filled with clean water, and when the two membrane assemblies and the entire system need to be cleaned, the water in the clean water tank can flow into the two membrane assemblies, thereby cleaning the two membrane assemblies and the system.

Preferably, as an improvement, the alkali liquid tank is connected to a waste alkali liquid effluent pump, and the acid liquid tank is connected to an ammonium sulfate effluent pump. Thus, after the system runs for a certain period, the liquid in the alkali liquid tank and the acid liquid tank needs to be discharged accordingly, so by opening the waste alkali liquid effluent pump and the ammonium sulfate effluent pump respectively, the waste liquid in the alkali liquid tank or the acid liquid tank can be discharged.

Preferably, as an improvement, it further comprises an alkali liquid replenishing tank and an acid liquid replenishing tank, the alkali liquid replenishing tank is connected to the alkali liquid replenishing pipe, and the acid liquid replenishing tank is connected to the acid liquid tank. Thus, the alkali liquid replenishing tank and the acid liquid replenishing tank are respectively filled with alkali liquid and acid liquid that need to be replenished, and when the alkali liquid or acid liquid needs to be replenished, the liquid in the alkali liquid replenishing tank or the acid liquid replenishing tank can be replenished into the corresponding alkali liquid tank or the acid liquid tank.

Preferably, as an improvement, a chamber is provided inside the stirring shaft, a chamber is also provided inside the blade, the chamber of the blade is connected to the chamber on the stirring shaft, and a liquid outlet is provided on the blade; the alkali solution replenishing pipe is connected to the chamber of the stirring shaft.

Therefore, when replenishing the strong alkali solution, the strong alkali solution enters the chamber of the stirring shaft through the alkali solution replenishing pipe, the strong alkali solution enters the chamber of the blade, and flows out from the liquid outlet holes of different blades. In this way, the strong alkali solution added to the alkali solution tank flows out from different blades. Therefore, the outflow position of the strong alkali solution is not fixed. The strong alkali solution flows out from all sides of the stirring shaft and flows all around, which is more conducive to mixing, stirring and dispersing the strong alkali solution and the liquid in the alkali solution tank, avoiding the situation where the position where the strong alkali solution is added is fixed and not conducive to rapid diffusion, thereby improving the detection accuracy of the pH detector and reducing the detection error.

Preferably, as an improvement, a connecting hole is provided on the side wall of the stirring shaft, and the connecting hole connects the chamber of the blade with the chamber of the stirring shaft. Thus, the connection between the chamber of the blade and the chamber of the stirring shaft is achieved through the connecting hole.

Preferably, as an improvement, the top of the stirring shaft is rotatably connected with a rotary joint, and the alkali liquid replenishing pipe is connected to the rotary joint. Thus, through the rotary joint, the alkali liquid replenishing pipe will not rotate with the stirring shaft, and the alkali liquid replenishing pipe can be in a stationary state.

Preferably, as an improvement, a flow meter is installed on the first pipeline, the second pipeline or the third pipeline, so that the flow rate of the liquid on the first pipeline, the second pipeline or the third pipeline can be detected by the flow meter.

Preferably, as an improvement, the pump is a metering pump. The metering pump can be adjusted steplessly within the range of 0-100% and is used to transport liquids (especially corrosive liquids). It is a special positive displacement pump, so the metering pump can transport acid and alkali liquids and wastewater, and can also adjust the delivery volume according to actual needs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a wastewater treatment system based on dialysis-denitrification.

FIG. 2 is a schematic structural diagram of an alkali solution tank in Example 1.

FIG3 is a schematic structural diagram of an alkali solution tank in Example 2.

FIG. 4 is a top view of the blade in FIG. 3 .

Figure 5 is a schematic diagram of the control logic of the control system.

FIG. 6 is a partial top view of the upper baffle and blades.

DETAILED DESCRIPTION

The following is further described in detail through specific implementation methods:

The figure marks in the drawings of the specification include: raw water tank 1, alkali liquid tank 2, acid liquid tank 3, security filter 4, first pump 5, Daonan dialysis assembly 6, third pump 7, second pump 8, valve 10, first pipeline 11, second pipeline 12, third pipeline 13, alkali liquid replenishing pipe 15, acid liquid replenishing pipe 16, motor 17, bracket 18, bearing 19, pH detector 20, stirring shaft 21, blade 22, driven gear 23, driving gear 24, rotary joint 25, electromagnet 26, connecting hole 27, blocking block 28, sliding rod 29, fixing block 30, rod bracket 31, compression spring 32, control system 33, water collection tank 34, clean water tank 35, alkali liquid replenishing tank 36, acid liquid replenishing tank 37, waste alkali liquid efflux pump 38, ammonium sulfate efflux pump 39, upper baffle 40, upper outlet hole 41, control hole 42.

Example 1

Basically as shown in Figures 1-2: A wastewater treatment system based on dialysis-denitrification, including a raw water tank 1, an alkali liquid tank 2 and an acid liquid tank 3, the raw water tank 1 and the civil water collection tank 34 are connected by a pipeline, wherein the water collection tank 34 collects ammonia-containing wastewater, regulates, stores, and homogenizes the wastewater, and the raw water tank 1 is configured as a DDOD complete set of equipment, as a storage device for raw water and effluent treated in a batch mode. A security filter 4 is provided between the raw water tank 1 and the water collection tank 34, and through the provision of the security filter 4, the liquid before entering the raw water tank 1 can be filtered to remove impurities in the water and avoid damage to the system.

A Daonan dialysis assembly 6 is provided between the raw water tank 1 and the alkali liquid tank 2, and a first pipe 11 is connected between the raw water tank 1 and the Daonan dialysis assembly 6. The liquid in the raw water tank 1 enters the Daonan dialysis assembly 6 through the first pipe 11, and flows back to the raw water tank 1 through the first pipe 11.

An osmotic distillation assembly is provided between the alkali liquid tank 2 and the acid liquid tank 3, and a second pipeline 12 is connected between the alkali liquid tank 2, the Daonan dialysis assembly 6 and the osmotic distillation assembly. A cation exchange membrane is provided inside the Daonan dialysis assembly 6, and the cation exchange membrane allows NH ₄ ⁺ to pass through. In this embodiment, the first pipeline 11 is located on one side of the cation exchange membrane, and the second pipeline 12 is located on the other side of the cation exchange membrane.

The liquid in the alkali liquid tank 2 flows out from the second pipe 12, enters the Donan dialysis assembly 6, then enters the osmotic distillation assembly along the second pipe 12, and finally returns to the alkali liquid tank 2 along the second pipe 12. A third pipe 13 is connected between the acid liquid tank 3 and the osmotic distillation assembly. The liquid in the acid liquid tank 3 flows into the osmotic distillation assembly through the third pipe 13, and flows back to the acid liquid tank 3 along the third pipe 13. The osmotic distillation assembly includes a gas-permeable hydrophobic membrane, the third pipe 13 is located on one side of the gas-permeable hydrophobic membrane, and the second pipe 12 is located on the other side of the gas-permeable hydrophobic membrane.

Wherein, the Daonan dialysis component 6 includes a shell and a cationic membrane, and the cationic membrane is fixed in the shell. The cationic membrane fixing method can be specifically: a clamp is provided inside the shell, and the clamp clamps the cationic membrane. The Daonan dialysis component 6 can be a single flat plate type or a stacked flat plate type. The difference between the single flat plate type and the stacked flat plate type is the number of membranes. The single flat plate type is a cationic membrane, and the stacked flat plate type is formed by stacking multiple cationic membranes. The stacked flat plate type is illustrated in Figure 1. The membrane size can be 650mm*1200mm, the effective area of the membrane is ^0.45m2 /piece, and the number of membrane assembly pieces is 3-250 pieces. For the Daonan dialysis component 6, it belongs to the prior art, and the Daonan dialysis component 6 of corresponding specifications can be selected according to actual needs. The Daonan dialysis component 6 is not the improvement of the present application, and will not be repeated here.

Wherein, the osmotic distillation component includes a shell and a breathable hydrophobic membrane, and the breathable hydrophobic membrane is fixed in the shell. The breathable hydrophobic membrane fixing method can be specifically: a clamping piece is provided inside the shell, and the clamping piece clamps the breathable hydrophobic membrane. The number of breathable hydrophobic membranes can be one, or a plurality of them can be stacked. The breathable hydrophobic membrane can be an unfolded plane or a curled cylindrical shape. The size of the membrane is 600mm*1200mm. For the osmotic distillation component, it belongs to the prior art, and the osmotic distillation component of corresponding specifications can be selected according to actual needs. The osmotic distillation component is not the improvement of the present application, and it will not be repeated here.

The first pipeline 11, the second pipeline 12, and the third pipeline 13 are all provided with pumps, and the pumps on the first pipeline 11, the second pipeline 12, and the third pipeline 13 are respectively the first pump 5, the second pump 8, and the third pump 7, and these pumps are all metering pumps. In addition, in other embodiments, a flow meter is installed on the first pipeline 11, the second pipeline 12, or the third pipeline 13.

As shown in FIG. 2 , a vertical stirring shaft 21 is provided in the alkali liquid tank 2, and a plurality of blades 22 are welded or fixed on the stirring shaft 21 by screws. The number of blades 22 in this embodiment is three. The blades 22 are located inside the alkali liquid tank 2, and a bracket 18 for supporting the stirring shaft 21 is provided on the outside of the alkali liquid tank 2, and a bearing 19 is connected between the bracket 18 and the stirring shaft 21. A driving mechanism for driving the stirring shaft 21 to rotate is provided on the outside of the alkali liquid tank 2, and the driving mechanism includes a motor 17, and the motor 17 is directly or indirectly connected to the stirring shaft 21 through a transmission component, wherein the indirect transmission power mode of the transmission component can be gear transmission, belt transmission, sprocket chain transmission, etc. The alkali liquid replenishment pipe 15 is connected to the alkali liquid tank 2, and the alkali liquid replenishment pipe 15 is connected to the top of the alkali liquid tank 2. A pH detector 20 for detecting the pH value in the alkali liquid tank 2 is provided on the left inner wall of the alkali liquid tank 2. The alkali liquid replenishment pipe 15 and the pH detector 20 are located on the left and right sides of the alkali liquid tank 2.

1 , the acid tank 3 is connected with an acid replenishing pipe 16 for replenishing acid into the acid tank 3. In addition, in this embodiment, valves 10 are installed and connected to the first pipe 11, the second pipe 12, the third pipe 13, the alkali replenishing pipe 15 and the acid replenishing pipe 16.

The raw water tank 1 is filled with waste water, the alkali solution tank 2 is filled with alkali solution, which may be a sodium hydroxide solution, and the acid solution tank 3 is filled with acid, such as a sulfuric acid solution.

Thus, in this embodiment, the wastewater in the raw water pool 1 flows to the first pipe 11 under the action of the first pump 5, and enters the Daonan dialysis assembly 6 after passing through the security filter 4. In FIG1, the cation exchange membrane is arranged vertically, and the wastewater liquid inputted into the Daonan dialysis assembly 6 by the first pipe 11 is located on the left side of the cation exchange membrane. The alkali solution in the alkali solution tank 2 enters the Daonan dialysis assembly 6 through the second pipe 12 under the action of the second pump 8. The alkali solution is located on the right side of the cation exchange membrane. Since the ammonium ion concentration on the left side of the cation exchange membrane is greater than the ammonium ion concentration on the right side, the ammonium ions in the wastewater and the driving ions in the alkali solution are replaced across the cation exchange membrane under the action of the concentration difference, and the ammonium ions move to the right to the right side of the cation exchange membrane, and the ammonium ions react with the hydroxide ions in the alkali solution to generate ammonia. The ammonia continues to enter the osmotic distillation assembly along the second pipe 12.

The air-permeable and hydrophobic membrane in the osmotic distillation assembly is arranged vertically, and the liquid and gas inputted into the osmotic distillation assembly by the second pipeline 12 are located on the left side of the air-permeable and hydrophobic membrane. The acid solution in the acid tank 3 enters the osmotic distillation assembly through the third pipeline 13 under the action of the third pump 7, and the acid solution is located on the right side of the air-permeable and hydrophobic membrane. Ammonia moves to the right across the air-permeable and hydrophobic membrane under the action of the pressure difference on both sides of the air-permeable and hydrophobic membrane and mixes with the acid solution. After the ammonia and the acid solution are mixed, they enter the acid tank 3 through the third pipeline 13, and after the ammonia and the acid solution are mixed, they are converted into ammonium salts for subsequent recycling.

The key point of the improvement of the present application is that the alkali liquid in the alkali liquid tank 2 in the present solution needs to maintain a certain alkalinity. As the alkali liquid is continuously circulated in the second pipe 12, the alkalinity of the alkali liquid in the alkali liquid tank 2 will gradually weaken. Therefore, after the alkali liquid tank 2 has been used for a period of time, it is necessary to supplement the alkali solution into the alkali liquid tank 2 through the alkali liquid supplement pipe 15 to ensure that the alkaline environment in the alkali liquid tank 2 meets the requirements. Specifically, an alkali liquid supplement tank 36 is provided on the outside of the alkali liquid tank 2, and the alkali liquid supplement tank 36 is connected to the alkali liquid tank 2 through the alkali liquid supplement pipe 15, and a pump is provided on the alkali liquid supplement pipe 15. When the strong alkali solution is supplemented into the alkali liquid tank 2, the stirring shaft 21 is driven to rotate by the driving mechanism, and the stirring shaft 21 drives the blades 22 to rotate, thereby stirring the alkali liquid in the alkali liquid tank 2, so that the strong alkali solution is added, stirred and mixed, so that the added strong alkali solution can be dispersed in the alkali liquid tank 2 more quickly. Compared with the case where the stirring shaft 21 is not provided, the strong alkali solution naturally and slowly disperses in the alkali liquid tank 2. In this way, the pH detector 20 on the inner wall of the alkali liquid tank 2 can detect the change of the pH value more quickly, reducing the detection delay of the pH detector 20 and the detection error of the pH detector 20 on the pH value, making the pH detector 20 more accurate in detecting the pH value, and being able to more accurately control the pH value in the alkali liquid tank 2, so that it is easier to accurately control the amount of strong alkali added. In this way, the pH value of the alkali liquid in the alkali liquid tank 2 can be more accurately controlled, so that the ion ammonium-ammonia gas can play a more effective role in a better pH environment, ensuring the effect of the entire system on the recovery and treatment of ammonia nitrogen in wastewater.

In addition, during the whole process of treating the wastewater, the stirring shaft 21 can also be continuously in a rotating state, so as to stir the wastewater in the alkali liquid tank 2 and ensure that the liquid in the alkali liquid tank 2 is continuously in a uniformly mixed state.

In addition, in this embodiment, the alkali liquid tank 2 is connected to a waste alkali liquid effluent pump 38, and the acid liquid tank 3 is connected to an ammonium sulfate effluent pump 39. Therefore, after the system runs for a certain period, the liquids in the alkali liquid tank 2 and the acid liquid tank 3 need to be discharged accordingly, so by opening the waste alkali liquid effluent pump 38 and the ammonium sulfate effluent pump 39 respectively, the waste liquid in the alkali liquid tank 2 or the acid liquid tank 3 can be discharged.

In addition, the present embodiment also includes a clean water tank 35, which is connected to the second pipe 12 and the third pipe 13 through a pipe (a pump is provided on the pipe), so that when it is necessary to clean the Donan dialysis component 6 and the osmotic distillation component or the entire system, the multiple valves 10 on the entire system are opened, and the clean water in the clean water tank 35 flows into the corresponding parts of the entire system through the pipe, thereby cleaning the corresponding parts of the entire system and the two membrane components.

Example 2

As shown in FIG3 , a vertical chamber is provided inside the stirring shaft 21, a chamber is also provided inside the blade 22, a connecting hole 27 is provided on the side wall of the stirring shaft 21, and the chamber of the blade 22 and the chamber on the stirring shaft 21 are connected through the connecting hole 27. A liquid outlet is provided on the end of the blade 22 away from the stirring shaft 21.

The top of the stirring shaft 21 is rotatably connected with a rotary joint 25, and the alkali liquid replenishing pipe 15 is connected to the rotary joint 25. The rotary joint 25 covers the top of the stirring shaft 21 and can rotate relatively. The alkali liquid replenishing pipe 15 is connected to the internal chamber of the stirring shaft 21 through the rotary joint 25. Therefore, when the stirring shaft 21 rotates, the rotary joint 25 and the top of the stirring shaft 21 rotate relatively, so that the alkali liquid replenishing pipe 15 does not rotate with the stirring shaft 21, and the alkali liquid replenishing pipe 15 is prevented from rotating due to the rotation of the stirring shaft 21 and causing the alkali liquid replenishing pipe 15 to be entangled.

In addition, in the present embodiment, a driven gear 23 is coaxially fixed (fixed by a key) on the stirring shaft 21, the motor 17 is mounted on the frame, and a driving gear 24 is fixedly mounted (fixed by a key or welding) on the output shaft of the motor 17, and the driving gear 24 and the driven gear 23 are meshed, whereby the motor 17 drives the driving gear 24 to rotate, and the driving gear 24 drives the driven gear 23 to rotate, thereby driving the stirring shaft 21 to rotate.

Thus, when the strong alkali solution is replenished, the strong alkali solution enters the chamber of the stirring shaft 21 through the alkali solution replenishing pipe 15, and the strong alkali solution in the stirring shaft 21 enters the chamber of the blade 22 through the connecting hole 27, and flows out from the liquid outlet holes on the plurality of blades 22. In this way, during the rotation of the stirring shaft 21, the strong alkali solution added to the alkali solution tank 2 flows out from different blades 22. Therefore, compared with the embodiment 1, the position where the strong alkali solution flows out is not fixed. The strong alkali solution flows out from all around the stirring shaft 21 and flows around. In this way, the strong alkali solution flows out from the blades 22. Finally, the strong alkali solution is located around the stirring shaft 21, which is more conducive to the mixing, stirring and dispersion of the strong alkali solution and the liquid in the alkali solution tank 2, avoids the strong alkali solution being added at a fixed position that is not conducive to rapid diffusion, avoids the strong alkali solution being added at a fixed position far away from the pH meter 20, which causes the pH meter 20 to not be able to detect it immediately and is too low, and avoids the strong alkali solution being added at a fixed position near the pH meter 20, which causes the detection value of the pH meter 20 to be too high, thereby improving the detection accuracy of the pH meter 20 and reducing the detection error.

Example 3

As shown in Figures 3 to 5, this embodiment is further optimized on the basis of Example 2. In this embodiment, the outer wall of the alkali liquid tank 2 is fixedly connected with an electromagnet 26. Specifically, the outer wall of the alkali liquid tank 2 is bonded or fixed with the electromagnet 26 by screws, and the electromagnet 26 is arranged circumferentially around the alkali liquid tank 2.

The inner wall of the liquid outlet of the blade 22 is inclined, and a block 28 is inserted into the liquid outlet of the blade 22. The block 28 is in the shape of a truncated cone. The block 28 is inserted into the liquid outlet, and the end of the block 28 located in the blade 22 is the small end, and the end of the block 28 located outside the blade 22 is the large end. The inclined surface of the block 28 matches and slides with the inner wall of the liquid outlet.

As shown in FIG4 , the outer side of the blade 22 is fixedly connected to the rod frame 31, and the fixing method is, for example, welding. The outer side of the block 28 is fixedly connected to the sliding rod 29, and the sliding rod 29 is fixed by screws or welding. The sliding rod 29 is bent and arranged. The sliding rod 29 includes a transverse part and a vertical part. The transverse part of the sliding rod 29 is slidably connected to the rod frame 31. Specifically, the rod frame 31 is provided with a hole for the sliding rod 29 to pass through transversely.

One end of the sliding rod 29 away from the blocking block 28 is fixedly connected to a fixing block 30 , for example, by welding. A compression spring 32 is connected between the fixing block 30 and the rod frame 31 , and the compression spring 32 is sleeved on the sliding rod 29 .

The end of the block 28 is made of a magnetic material. For example, a magnet is fixed to the end of the block 28 by a screw, and there is an attractive force between the opposing surfaces of the electromagnet 26 and the block 28.

The wastewater treatment system in this embodiment further includes a control system 33 (such as a PLC control system), the input end of the control system 33 is electrically connected to the pH detector 20, and the output end of the control system 33 is electrically connected to the motor 17 and the electromagnet 26. The pH value signal detected by the pH detector 20 is transmitted to the control system 33, and the control system 33 controls the speed of the motor 17 and the magnetic force of the electromagnet 26 according to the pH value.

The control system 33 controls the rotation speed of the motor 17 and the magnetic force of the electromagnet 26 according to the pH value. Specifically, the control system 33 can control the rotation speed of the motor 17 and the magnetic force of the electromagnet 26 by controlling the current supplied to the motor 17 and the electromagnet 26, and the current control is easy to implement. For example, the control system 33 controls the driving component, and the driving component (which can be a cylinder or an electric cylinder) controls the sliding of the sliding rheostat to control the current, thereby realizing the change of the current through the motor 17 and the electromagnet 23.

In this embodiment, when the pH detector 20 detects that the pH value in the alkali liquid tank 2 is lower than a certain value, for example, when the pH value is lower than 12, the control system 33 receives the signal detected by the pH detector 20, and the control system 33 controls the motor 17 to increase the rotation speed. At the same time, the control system 33 controls the magnetic force of the electromagnet 26 to increase, so that the attraction between the electromagnet 26 and the block 28 increases, the gravitational force of the block 28 is greater than the elastic force of the compression spring 32, the block 28 moves toward the electromagnet 26, and the compression degree of the compression spring 32 increases. Since the shape of the block 28 is a truncated cone, the opening degree of the liquid outlet hole on the blade 22 increases, so that more strong alkali solution flows out. In addition, the speed at which the motor 17 drives the stirring shaft 21 to rotate is also relatively large, which improves the stirring of the liquid, and can make more strong alkali solution disperse quickly, so as to ensure the speed and efficiency of adding the strong alkali solution into the alkali liquid tank 2 and dispersing the strong alkali solution.

As the strong alkaline solution is continuously added, the pH meter 20 detects that the pH value is continuously increasing. At this time, the control system 33 receives the detection signal of the pH meter 20, and the control system 33 controls the speed of the motor 17 to gradually decrease. At the same time, the control system 33 controls the magnetic force of the electromagnet 26 to gradually decrease, so that the attraction between the electromagnet 26 and the block 28 becomes smaller, and the block 28 gradually moves toward the inside of the blade 22 under the elastic force of the compression spring 32. Therefore, the opening degree of the liquid outlet gradually decreases, so that the outflow rate of the strong alkaline solution gradually decreases. In this way, when the pH value is about to reach the required value (for example, the required pH value is 13), the strong alkaline solution is prevented from flowing out too fast and being added in excess, so that the strong alkaline solution is added slowly.

When the pH detector 20 detects that the pH value in the alkali liquid tank 2 meets the requirements, for example, when the pH value reaches 13, the control system 33 receives the signal detected by the pH detector 20, and the control system 33 controls the motor 17 to rotate at a low speed. At the same time, the control system 33 controls the magnetic force of the electromagnet 26 to be zero (that is, the electromagnet 26 is not energized, and the circuit where the electromagnet 26 is located is disconnected), so that the attraction between the electromagnet 26 and the block 28 disappears, and the block 28 moves toward the inner direction of the blade 22 through the sliding rod 29 under the action of the compression spring 32 to completely block the liquid outlet, so that the strong alkaline solution will not flow out. In addition, the motor 17 drives the stirring shaft 21 to rotate at a low speed, and the stirring shaft 21 stirs the liquid at a low speed, which can reduce the liquid impact on the pH detector 20 and increase the service life of the pH detector 20. At the same time, it can also avoid the stirring shaft 21 from continuously rotating at a high speed and wasting energy, which is more energy-saving.

Thus, the present embodiment realizes automatic control of the motor 17 and the opening degree of the liquid outlet, and when the rotation speed of the stirring shaft 21 is high, the stirring efficiency can be improved, and the liquid outlet speed of the liquid outlet is high, which can ensure the stirring and mixing efficiency. When it is not necessary to add the strong alkaline solution, the liquid outlet is automatically closed, and the rotation speed of the stirring shaft 21 is low, which reduces energy waste and impact on the pH detector 20.

Example 4

In this embodiment, the top and bottom of the blade 22 are respectively provided with an upper outlet hole 41 and a lower outlet hole, and the block 28 is fixedly connected (for example, welded) with an upper baffle 40 located above the blade 22 and a lower baffle located below the blade 22, as shown in FIG6 . The upper baffle 40 and the blade are related to each other, and a vertical control hole 42 is provided on both the upper baffle 40 and the lower baffle. The control hole 42 on the upper baffle 40 and the control hole 42 on the lower baffle can be respectively opposite to the upper outlet hole 41 and the lower outlet hole on the blade 22, and the control hole 42, the lower outlet hole and the upper outlet hole 41 are of the same shape and equal size. When the block 28 completely blocks the liquid outlet hole, the control hole 42 on the upper baffle 40 and the upper outlet hole 41 are completely staggered, and the control hole 42 on the lower baffle and the lower outlet hole are completely staggered. At this time, the upper baffle 40 blocks and blocks the upper outlet hole 41, and the lower baffle blocks and blocks the lower outlet hole. At this time, the upper outlet hole 41 and the lower outlet hole will not discharge liquid.

When the rotation speed of the stirring shaft 21 increases, the block 28 moves away from the stirring shaft 21. For example, in FIG6 , the block 28 drives the upper baffle 40 and the lower baffle to move to the left. At this time, the control hole 42 and the upper outlet hole 41 of the upper baffle 40 change from the staggered state to the connected state, and the control hole 42 and the lower outlet hole of the lower baffle change from the staggered state to the connected state. The upper outlet hole 41 and the lower outlet hole are both opened to discharge liquid, so that the supplemented strong alkali liquid can not only flow out laterally from the outlet hole at the end of the blade, but also flow out vertically upward and downward from the top of the blade, so that the strong alkali liquid flows out in multiple directions and is more evenly dispersed. In addition, as the rotation speed of the stirring shaft 21 increases, the block 28 drives the upper baffle 40 and the lower baffle to move a greater distance, the upper outlet hole 41 and the control hole 42 have a greater relative degree, and the lower outlet hole and the control hole 42 have a greater relative degree, so that the upper outlet hole 41 and the lower outlet hole are opened to a greater extent, and the strong alkali liquid can flow out quickly in the upward and downward directions. When the rotation speed of the stirring shaft 21 decreases, the block 28 in the figure moves in the opposite direction to the right, the upper outlet hole 41 and the control hole 42 become smaller relative to each other, and the lower outlet hole and the control hole 42 also become smaller relative to each other, thereby slowing down the outflow speed of the strong alkali solution, avoiding excessive addition due to the strong alkali solution flowing out too fast.

The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and/or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims (9)

1. A wastewater treatment system based on dialysis-denitrification, characterized in that it comprises a raw water pool, an alkali liquid tank, an acid liquid tank and an alkali liquid replenishing pipe for replenishing strong alkali into the alkali liquid tank, a Daonan dialysis assembly is arranged between the raw water pool and the alkali liquid tank, a first pipeline is connected between the raw water pool and the Daonan dialysis assembly; an osmotic distillation assembly is arranged between the alkali liquid tank and the acid liquid tank, a second pipeline is connected between the alkali liquid tank, the Daonan dialysis assembly and the osmotic distillation assembly, the liquid in the alkali liquid tank enters the Daonan dialysis assembly and the osmotic distillation assembly in turn along the second pipeline and then returns to the alkali liquid tank; a third pipeline is connected between the acid liquid tank and the osmotic distillation assembly; pumps are arranged on the first pipeline, the second pipeline and the third pipeline; a pH detector is installed on the inner wall of the alkali liquid tank, a stirring shaft is arranged in the alkali liquid tank, a plurality of blades are fixed on the stirring shaft, the blades are located inside the alkali liquid tank, a driving mechanism for driving the stirring shaft to rotate is arranged on the outer side of the alkali liquid tank, and the driving mechanism comprises a motor; The interior of the stirring shaft is provided with a chamber, the interior of the blade is also provided with a chamber, the chamber of the blade is communicated with the chamber on the stirring shaft, and the blade is provided with a liquid outlet; the alkali solution replenishing pipe is communicated with the chamber of the stirring shaft; The outer wall of the alkali liquid tank is fixedly connected with an electromagnet, which is arranged circumferentially around the alkali liquid tank; the inner wall of the liquid outlet of the blade is inclined, and a block is inserted into the liquid outlet of the blade. The block is in the shape of a truncated cone and is inserted into the liquid outlet. The end of the block located in the blade is the small end, and the end of the block located outside the blade is the large end; the inclined surface of the block matches the inner wall of the liquid outlet and slides together; The outer side of the blade is fixedly connected to the rod frame, the outer side of the block is fixedly connected to a sliding rod, the sliding rod includes a transverse portion and a vertical portion, the transverse portion of the sliding rod is slidably connected to the rod frame; one end of the sliding rod away from the block is fixedly connected to a fixed block, and a compression spring is connected between the fixed block and the rod frame; The end of the block is made of a magnetic material, and there is attraction between the mutually opposite surfaces of the electromagnet and the block; The wastewater treatment system based on dialysis-denitrification also includes a control system, the input end of the control system is electrically connected to the pH detector, and the output end of the control system is electrically connected to the motor and the electromagnet; the pH value signal detected by the pH detector is transmitted to the control system, and the control system controls the speed of the motor and the magnetic force of the electromagnet according to the pH value. 2. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that: the raw water tank is connected to a water collecting tank, and a safety filter is provided between the raw water tank and the water collecting tank. 3. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that it also includes a clean water tank for cleaning the Donan dialysis component and the osmotic distillation component. 4. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that: the alkali liquid tank is connected to a waste alkali liquid efflux pump, and the acid liquid tank is connected to an ammonium sulfate efflux pump. 5. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that it also includes an alkali solution replenishing tank and an acid solution replenishing tank, the alkali solution replenishing tank is connected to the alkali solution replenishing pipe, and the acid solution replenishing tank is connected to the acid solution tank. 6. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that a connecting hole is provided on the side wall of the stirring shaft, and the connecting hole connects the chamber of the blade and the chamber of the stirring shaft. 7. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that: a rotary joint is rotatably connected to the top of the stirring shaft, and the alkali solution replenishing pipe is connected to the rotary joint. 8. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that a flow meter is installed on the first pipeline, the second pipeline or the third pipeline. 9. A wastewater treatment system based on dialysis-denitrification according to claim 1, characterized in that the pump is a metering pump.