CN117735662A - Symmetrical siphon separation method for controlling water pollution - Google Patents

Abstract

The invention relates to the field of water pollution control and discloses a symmetrical siphon separation method for controlling water pollution, which comprises the steps of using a symmetrical double-siphon centrifugal machine to carry out solid-liquid separation on suspension liquid of polluted water, adding the suspension liquid into a rotary drum of the siphon centrifugal machine to carry out centrifugal separation treatment, and carrying out siphon drainage at the front end and the rear end of the rotary drum of the siphon centrifugal machine; stopping adding the suspension after the thickness of the filter cake in the rotary drum reaches the preset loading amount, discharging after the rotary drum continuously runs for a preset time, and backflushing the rotary drum filter medium after discharging. The invention can solve the problems of low separation efficiency and poor separation effect caused by unbalanced separation due to the adoption of single-side siphon separation in the existing sewage and wastewater treatment process.

Description

A symmetrical siphon separation method for water pollution control

Technical field

The invention relates to the field of water pollution control, and in particular to a symmetrical siphon separation method for water pollution control.

Background technique

With the rapid development of industry and the continuous growth of population, the discharge of wastewater has increased year by year, seriously polluting rivers, lakes and groundwater, causing a significant decline in water quality. First, the main source of water pollution is industrial wastewater. Because a large amount of wastewater is produced during industrial production, it contains various harmful substances, such as heavy metals, organic matter, acids and alkalis, etc. These substances cause serious pollution to water bodies. In addition, in order to pursue economic benefits, some factories often discharge wastewater directly into rivers and lakes without treatment, which is also one of the main causes of water pollution. Secondly, domestic sewage is also one of the important sources of water pollution. All kinds of sewage produced in people's daily life, such as water used for washing and sanitation, contain a large amount of organic matter, nutrient salts and other pollutants. This sewage will not only pollute rivers and lakes, but also affect the quality of groundwater.

Centrifugal separation is a commonly used solid-liquid separation technology in sewage treatment and industrial wastewater treatment processes. Among the commonly used solid-liquid separation equipment, the siphon scraper centrifuge can effectively separate solid suspensions from liquids, thereby improving water quality. At the same time, it can also remove contaminants such as grease and heavy metal ions in water, so it is also widely used in the treatment of food processing wastewater, electroplating wastewater, etc. In addition, in circulating water treatment, the siphon scraper centrifuge can effectively remove impurities, algae, microorganisms, etc. in the water, thereby preventing pipeline blockage and corrosion. However, the existing siphon scraper centrifuge uses a single-sided siphon tube to discharge liquid. After the liquid phase of the separated slurry passes through the filter medium (filter cloth), the liquid phase at the front end of the drum needs to pass from the front end of the drum in the filter channel of the filter plate. , passes through the entire length of the drum, reaches the rear end of the drum, enters the siphon chamber through the siphon hole at the bottom of the drum, and then is discharged out of the centrifuge through the siphon chamber at the rear end. The liquid phase drainage path is longer, and the liquid phase separation efficiency is relatively Low. During the separation process, some small particles of solid phase will pass through the filter medium (filter cloth), especially at the siphon end. Due to the siphon force brought by the siphon chamber, some materials at the bottom of the drum will filter out more, which may cause the drum to filter out. , the material will become unbalanced, which will cause the drum to vibrate during operation. Long-term vibration will reduce the service life of the equipment. And due to the asymmetry of one-sided liquid discharge, imbalance will occur in the separation of some materials, resulting in poor separation of solid phase substances in sewage and wastewater, failing to meet the preset standards, and increasing the impact on sewage and wastewater. Dealing with costs again.

Contents of the invention

The present invention intends to provide a symmetrical siphon separation method for water pollution control to solve the existing problems of single-sided siphon separation for solid-liquid separation in sewage and wastewater treatment processes, which has low separation efficiency and unbalanced separation, resulting in poor separation effect.

In order to achieve the above object, the present invention adopts the following technical solution: a symmetrical siphon separation method for water pollution control, including the following steps:

A. Prepare the siphon centrifuge;

B. Treat the polluted water to be separated into a suspension;

C. Start the siphon centrifuge to rotate the drum, add the suspension into the drum of the siphon centrifuge for centrifugal separation, and perform siphon drainage at both ends of the drum of the siphon centrifuge;

D. Stop adding the suspension when the thickness of the filter cake in the drum reaches the preset charging amount. The drum continues to run for the preset time before unloading. After unloading, the drum filter medium is backflushed;

E. Carry out the next solid-liquid separation process.

Preferably, as an improvement, in step A, the front end of the drum of the siphon centrifuge is provided with a front siphon chamber and the rear end is provided with a rear siphon chamber. The siphon centrifuge is provided with a front siphon tube that can rotate into the front siphon chamber, and a front siphon tube that can rotate into the rear siphon chamber. Rear siphon of siphon chamber.

Preferably, as an improvement, the front siphon tube and the rear siphon tube in step A are symmetrically distributed about the geometric center of the drum, so that balanced siphon drainage is performed at the front and rear ends of the drum in step C.

Preferably, as an improvement, in step C, the front siphon tube and the rear siphon tube enter the front siphon chamber and the rear siphon chamber at the same time for siphon drainage.

Preferably, as an improvement, in step A, the size and volume of the front siphon chamber and the rear siphon chamber are the same, and the inner diameters of the front siphon tube and the rear siphon tube are the same, so that the siphon discharge volume at the front and rear ends of the drum in step C is balanced.

Preferably, as an improvement, in step C, after the suspension enters the siphon centrifuge, a conical distribution bucket is used to evenly distribute the suspension into the drum along the axial direction of the drum.

Preferably, as an improvement, in step D, a front recoil pipe is set at the front end of the drum of the siphon centrifuge, and a rear recoil pipe is set at the rear end of the drum. The front recoil pipe and the rear recoil pipe are used to move forward respectively. The liquid discharged by the siphon is injected into the siphon chamber and the rear siphon chamber for backflushing.

Preferably, as an improvement, in step D, the front recoil pipe and the front siphon pipe are symmetrically distributed at right angles to both sides of the drum axis, and the rear recoil pipe and the rear siphon pipe are symmetrically distributed at right angles to both sides of the drum axis.

Preferably, as an improvement, in step D, the front recoil pipe and the rear recoil pipe simultaneously inject liquid into the front siphon chamber and the rear siphon chamber for recoil.

Preferably, as an improvement, the suspension in step B is a suspension containing particles with a diameter of 0.01mm-5mm, or a suspension containing a fiber length less than 4mm, and the concentration range of the suspension is between 10% and 60%.

The principle and advantage of this solution are: In actual application, sewage and wastewater still contain a large amount of harmful substances after preliminary sedimentation and filtration treatment. Usually, flocculants are added to them to flocculate some harmful substances, and then solid-liquid separation is performed. The technical solution of the present invention is to treat the polluted water to be treated into a suspension, inject it into a symmetrical double siphon centrifuge according to a certain concentration, and centrifuge the suspension through a rotating drum in the symmetrical double siphon centrifuge, so that the solid phase settles in On the filter plate, the liquid phase passes through the filter plate and enters the siphon chamber. By setting up a front siphon chamber and a rear siphon chamber on the drum and using centrally symmetrically distributed front siphon tubes and rear siphon tubes, siphon discharge is performed at the front and rear ends of the drum with the same flow rate. liquid. After the solid-liquid separation, the liquid phase discharged by the siphon is simultaneously injected into the centrally symmetrically distributed front recoil pipe and the rear recoil pipe to backwash the filter plate, and the separated liquid phase is fully utilized for filter screen regeneration.

Advantages of the present invention include:

1. The liquid at the front end of the drum is siphoned out from the front side and only needs to pass through half the length of the drum. Compared with the single-side siphon centrifuge, the drainage path is reduced by half; while the liquid at the rear end of the drum is discharged from the rear side of the drum and only needs to pass through half the length of the drum. The length of the drum that needs to pass halfway is reduced by half compared to the drainage path of a single-sided siphon centrifuge. Therefore, the overall liquid phase drainage path is shorter, and the liquid phase separation and discharge efficiency is higher during the contaminated water treatment process.

2. Using double siphon method, due to the front and rear arrangement, symmetrical distribution and simultaneous and same-flow siphon drainage, the drum and the materials in the drum can maintain a good balance during the liquid phase separation process. There will be no vibration and the material will not be unbalanced, so the liquid phase separation can maintain high efficiency and stability, and the solid-liquid separation effect of contaminated water is better.

3. Using double siphon suction force, the separation time is shorter than ordinary centrifuges, the liquid phase separation is more thorough, and the output per unit time is higher. Therefore, the double siphon centrifugation method has higher separation efficiency than traditional single-side siphon centrifugation.

4. At the same time, according to different material requirements, the program can be set to select the front siphon to discharge the mother liquor and the rear siphon to discharge the washing liquid to achieve separate discharge purposes; they can also be discharged together to reduce discharge time and improve efficiency.

5. Backwash liquid can be added to both sides of the siphon chamber at the same time to flush the residual filter cake. The backwash liquid can be the mother liquor or washing liquid discharged by the siphon to reduce water costs; both sides can be backwashed at the same time to flush more thoroughly and improve the filter cake regeneration ability. Stronger, ensuring better permeability of the filter media, longer service life of the filter cloth, and lower cost for solid-liquid separation of contaminated water.

Description of drawings

Figure 1 is a schematic structural diagram of a symmetrical double siphon centrifuge in an embodiment of the present invention.

Figure 2 is a partial enlarged view of position A in Figure 1.

Detailed ways

The following is further detailed through specific implementation methods:

The reference numbers in the drawings of the description include: casing 1, drum cylinder 2, scraper 3, siphon hole 4, rear siphon 5, rotating arm 6, rear support plate 7, motor 8, rear recoil pipe 9, rear Siphon chamber 10, washing pipe 11, cloth hopper 12, filter plate 13, front siphon pipe 14, support seat 15, slag discharge port 16, discharge barrel 17, door cover 18, discharge screw 19, front recoil pipe 20, inlet Material tube 21, front siphon chamber 22.

Embodiment, a symmetrical siphon separation method for water pollution control, including the following steps:

A. Prepare the siphon centrifuge; the front end of the drum of the siphon centrifuge is equipped with a front siphon chamber and the rear end is equipped with a rear siphon chamber. The siphon centrifuge is equipped with a front siphon tube that can rotate into the front siphon chamber, and a rear siphon tube that can rotate into the rear siphon chamber. The siphon tube, the front siphon tube and the rear siphon tube are symmetrically distributed around the geometric center of the drum. The size and volume of the front siphon chamber and the rear siphon chamber are the same. The inner diameters of the front siphon tube and the rear siphon tube are the same; a front backwash is set at the front end of the drum of the siphon centrifuge. Pipe, a rear recoil pipe is set at the rear end of the drum, the front recoil pipe and the front siphon pipe are symmetrically distributed on both sides of the drum axis at right angles, and the rear recoil pipe and the rear siphon pipe are symmetrically distributed on both sides of the drum axis at right angles;

B. Treat the polluted water to be separated into a suspension with a particle diameter of 0.01mm-5mm or a fiber length less than 4mm. The concentration range of the suspension is 10%-60 %between;

C. Start the siphon centrifuge to rotate the drum. Add the suspension into the drum of the siphon centrifuge for centrifugal separation. After the suspension enters the siphon centrifuge, use a conical distribution bucket to evenly distribute the suspension along the axial direction of the drum. In the drum, the front siphon pipe and the rear siphon pipe enter the front siphon chamber and the rear siphon chamber at the front and rear ends of the drum at the same time for balanced siphon drainage;

D. Stop adding the suspension when the thickness of the filter cake in the drum reaches the preset charging amount. The drum continues to run for the preset time before unloading. After unloading, use the front recoil pipe and the rear recoil pipe to siphon forward at the same time. The liquid discharged from the siphon is injected into the chamber and rear siphon chamber to backflush the drum filter medium;

E. Carry out the next solid-liquid separation process.

This embodiment provides a symmetrical double siphon centrifuge used in conjunction with the symmetrical siphon separation method for water pollution control. It is basically as shown in Figures 1 and 2: it includes a base shell 1, and the base shell 1 includes a welded On the housing 1 on the machine base, a rear support plate 7 is welded to the rear end of the housing 1, and a door cover 18 is hinged to the front end of the housing 1 through a hinge. The door cover 18 can be locked to the housing 1 through hydraulic locking. The specific structure is consistent with the existing siphon scraper 3 centrifuge and will not be described again. A rotating drum is installed in the machine base shell 1. The rotating drum is welded with a main shaft. The main shaft is connected to the rear support plate 7 through a bearing. The rear end of the main shaft is connected to a motor 8 through a belt drive. The front end of the drum is open and integrally formed with an annular liquid baffle. The drum in front of the liquid baffle is provided with an annular front siphon chamber 22. The middle section of the drum is the drum cylinder 2. The rear end of the drum is provided with an annular rear siphon chamber. The siphon chamber 10, the front siphon chamber 22, and the rear siphon chamber 10 are all provided with openings toward the axis of the drum. The inner wall of the drum cylinder 2 is embedded with a number of filter plates 13 along the circumferential direction. The filter plates 13 are connected to the inner wall of the drum cylinder 2. A dehydration chamber is formed between them. The bottoms of the front siphon chamber 22 and the rear siphon chamber 10 are provided with siphon holes 4 connected with the dehydration chamber. There are multiple siphon holes 4 evenly distributed along the circumferential direction of the drum. The door cover 18 and the rear support plate 7 are equipped with siphon components. The two siphon components are centrally symmetrically distributed with the geometric center of the drum. The siphon component includes an L-shaped siphon. The short side of the siphon extends into the inside of the machine base shell 1. The long side bearing of the siphon pipe is installed in a support base 15. The support base 15 is bolted to the door cover 18 and the rear support plate 7. The long side of the siphon pipe is bolted to a rotating arm 6, and the rotating arm 6 is hinged to a bolt and fixed to the base shell. The oil cylinder on the body 1 can push the rotating arm 6 to rotate the siphon, and then the short side of the siphon rotates into the front siphon chamber 22 and the rear siphon chamber 10.

The door cover 18 and the rear support plate 7 are bolted with a recoil pipe assembly. The recoil pipe assembly includes an L-shaped recoil pipe. A flange is welded to the recoil pipe. The flange is connected to the door cover 18 and the rear support plate. Plate 7 is connected with bolts. The short side outlet of the recoil pipe faces the front siphon chamber 22 and the rear siphon chamber 10. The two recoil pipe assemblies are centrally symmetrically distributed with the geometric center of the drum. The recoil pipe assembly and the siphon pipe assembly are distributed symmetrically at right angles. on both sides of the drum axis.

A horizontally penetrating discharge barrel 17 is welded in the middle of the door cover 18. The discharge barrel 17 extends transversely into the drum. A discharge screw 19 is provided in the discharge barrel 17. The discharge barrel 17 is located at the end outside the door cover 18. A slag discharge port 16 is provided, and the end of the discharge tube 17 located in the drum opens upward. The door cover 18 above the discharge barrel 17 is connected with 3 scraper racks extending into the drum cylinder 2 through bearings. The scraper 3 racks are bolted with a scraper 3 facing the upper side of the drum cylinder 2. The scraper 3 is located on the discharge barrel. Above the opening of barrel 17. The door cover 18 above the discharge barrel 17 is provided with a feed pipe 21. The feed pipe 21 extends transversely into the drum and is welded with a distribution hopper 12. The distribution hopper 12 faces the inner wall of the drum body 2. The door cover 18 below the discharge barrel 17 is provided with a washing pipe 11 extending into the drum. The washing pipe 11 is provided with an opening toward the inner wall of the drum body 2 . The unloading, feeding and washing structures of this part are the same as those of the siphon scraper 3 centrifuge in the prior art. For details, please refer to the siphon scraper 3 centrifuge in the prior art.

The use process of this symmetrical double siphon centrifuge is as follows: the motor 8 drives the main shaft and the drum to rotate through the belt drive. The material enters the drum from the feed pipe 21 and the distribution hopper 12. The drum rotates to centrifuge the material, and the solid phase settles in the filter. A filter cake is formed on the plate 13, and the liquid phase passes through the filter cake and enters the dehydration chamber, siphon hole 4, front siphon chamber 22, and rear siphon chamber 10. The siphon tubes in the front siphon tube 14 assembly and the rear siphon tube 5 assembly are driven to rotate by the oil cylinder driving the rotating arm 6, and the nozzles of the siphon tubes enter the front siphon chamber 22 and the rear siphon chamber 10.

The filtration driving force of the siphon scraper 3 centrifuge depends on the pressure difference on both sides of the filter screen, which is directly proportional to the liquid level height Ho in the drum and inversely proportional to the thickness H’ of the filter cake layer. The siphon scraper 3 centrifuge uses the siphon principle on the outside of the filter to increase the pressure difference on both sides of the filter medium, ultimately achieving the purpose of increasing the filtration speed. Since the siphon can swing back and forth, there is a variable liquid level difference Hu between the siphon mouth and the outside of the filter. When the position of the siphon suction is lower than the outside of the filter, Hu is a positive value. At this time, the siphon scraper 3 is pushed forward by the centrifuge filter In addition to the centrifugal force generated by high-speed rotation, a siphon force is also added to the outside of the filter. When the height of the siphon suction port is the same as the outside of the filter, Hu is 0. At this time, there is no siphon effect, and the filtration driving force is only centrifugal force. When the position of the siphon suction port is higher than the outside of the filter, Hu is a negative value. At this time, not only There is no siphon effect, and it also hinders filtration. The siphon scraper 3 centrifuge uses changes in Hu to achieve filtration, washing and separation of materials.

The centrifugal speed of the centrifuge depends on the pressure difference on both sides of the filter medium (7) and the liquid level of the drum, that is:

V＝K’(△P/H’)＝K(H0/H’)

In the formula:

V—filtration speed

△P—pressure difference on both sides of the filter medium

K, K’—proportionality constant

H’—Thickness of filter cake layer

H0—liquid level height

In addition to the centrifugal speed of this centrifuge, the front and rear siphon tube 5 components also increase the siphon suction force, so its separation speed is also related to the position of the siphon tube mouth, that is:

V＝K(Ho+Hu)/H'

Hu—the height difference between the suction port of the siphon and the outer surface of the filter medium.

The main functions of the siphon device:

Recoil stage: Hu is a negative value, and the recoil fluid passes through the front recoil pipe 20 and the rear recoil pipe 9 and joins the front siphon chamber 22 and the rear siphon chamber 10; under the action of centrifugal force, the front siphon chamber 22 and the rear siphon chamber The 10-mile backwash liquid enters the drum through the front siphon 14 and the rear siphon 5. After a certain amount is added, the backwash liquid will reversely penetrate from the filter medium to backwash the residual filter cake and soften the residual filter cake. , the filter plate 13 is regenerated.

Feeding stage: Hu is a positive, zero or negative value. The solid-liquid mixed slurry is added into the drum through the feeding pipe 21. Under the action of the centrifuge force, the solid phase is intercepted by the filter medium to form a uniform thickness filter cake; the liquid The phase passes through the filter cake, filter medium, and filter plate 13 and then flows through the filter channel of the filter plate 13 to the front and rear ends of the drum, and enters the front siphon chamber 22 and the rear siphon chamber 10 through the front and rear siphon holes 4 respectively; finally It is discharged out of the centrifuge through the front siphon 14 and the rear siphon 5.

Washing stage: Hu is zero or negative. The washing liquid passes through the washing pipe 11 and is first evenly sprayed on the solid phase filter cake layer. Then the washing liquid will pass through the solid phase filter cake layer under the action of centrifugal force to achieve washing. The function of the entire filter cake; at the same time, the front siphon 14 and the rear siphon 5 can be controlled to return to the starting position, so that the washing liquid will not be discharged from the centrifuge at this time, but will reach a certain liquid level, thereby achieving the effect of soaking and washing; The material is washed more thoroughly, the washing liquid is saved, and the washing effect is better.

Spin-drying stage: Hμ reaches the maximum positive value. At this time, the filtration driving force is the largest and the centrifugation effect is the best.

Since the diameter of the siphon chamber is larger than the diameter of the drum, as long as the solid-liquid phase can be separated under the action of centrifugal force, all the liquid phases will enter the front siphon chamber 22 and the rear siphon chamber 10 and be discharged out of the centrifuge.

The above are only embodiments of the present invention, and common knowledge such as specific technical solutions and/or characteristics that are known in the scheme are 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. These should also be regarded as the protection scope of the present invention, and they will not affect the implementation of the present invention. The effect and practicality of the patent. The scope of protection claimed in this application shall be based on the content of the claims, and the specific implementation modes and other records in the description may be used to interpret the content of the claims.

Claims (10)

1. A symmetrical siphon separation method for water pollution control, characterized by: including the following steps: A. Prepare the siphon centrifuge; B. Treat the polluted water to be separated into a suspension; C. Start the siphon centrifuge to rotate the drum, add the suspension into the drum of the siphon centrifuge for centrifugal separation, and perform siphon drainage at both ends of the drum of the siphon centrifuge; D. Stop adding the suspension when the thickness of the filter cake in the drum reaches the preset charging amount. The drum continues to run for the preset time before unloading. After unloading, the drum filter medium is backflushed; E. Carry out the next solid-liquid separation process. 2. A symmetrical siphon separation method for water pollution control according to claim 1, characterized in that: in step A, the front end of the drum of the siphon centrifuge is provided with a front siphon chamber and the rear end is provided with a rear siphon chamber, The siphon centrifuge is provided with a front siphon tube that can rotate into the front siphon chamber and a rear siphon tube that can rotate into the rear siphon chamber. 3. A symmetrical siphon separation method for water pollution control according to claim 2, characterized in that: in step A, the front siphon and the rear siphon are symmetrically distributed with the geometric center of the drum, so that in step C, the Balanced siphon drainage is performed at the front and rear ends of the drum. 4. A symmetrical siphon separation method for water pollution control according to claim 3, characterized in that in step C, the front siphon and the rear siphon enter the front siphon chamber and the rear siphon chamber at the same time for siphon drainage. 5. A symmetrical siphon separation method for water pollution control according to claim 4, characterized in that: in step A, the size and volume of the front siphon chamber and the rear siphon chamber are the same, and the inner diameters of the front siphon tube and the rear siphon tube are the same. , to balance the siphon discharge volume at the front and rear ends of the drum in step C. 6. A symmetrical siphon separation method for water pollution control according to claim 5, characterized in that: in step C, after the suspension enters the siphon centrifuge, a conical distribution bucket is used to evenly distribute the suspension along the axial direction of the drum. Distributed into the drum. 7. A symmetrical siphon separation method for water pollution control according to claim 5, characterized in that: in step D, a front backwash pipe is provided at the front end of the drum of the siphon centrifuge, and a front recoil pipe is provided at the rear end of the drum. The rear recoil pipe uses the front recoil pipe and the rear recoil pipe to inject the liquid discharged by the siphon into the front siphon chamber and the rear siphon chamber respectively for recoil. 8. A symmetrical siphon separation method for water pollution control according to claim 7, characterized in that: in step D, the front recoil pipe and the front siphon pipe are symmetrically distributed at right angles to both sides of the drum axis, and the rear recoil pipe is The flushing pipe and the rear siphon are symmetrically distributed at right angles to both sides of the drum axis. 9. A symmetrical siphon separation method for water pollution control according to claim 8, characterized in that in step D, the front recoil pipe and the rear recoil pipe simultaneously inject liquid into the forward siphon chamber and the rear siphon chamber. Backlash. 10. A symmetrical siphon separation method for water pollution control according to claim 1, characterized in that: the suspension in step B is a suspension containing particles with a diameter of 0.01mm-5mm, or a fiber with a length less than 4mm. The concentration range of the suspension is between 10% and 60%.