KR100988474B1 - Flocculation basin for treatment of drinking water and wastewater - Google Patents

Abstract

The present invention relates to a floc forming paper for treating water and sewage water, and to effectively collide the fine particles contained in the water to be treated to form a large and heavy floc that is easy to settle, and includes a filter sponge, anthracite, and fiber yarn. Filtered floc forming module composed of the same media layer, vortex agitating floc forming module designed to effectively cause collision between particles, vortex, agitation, upflow laminar floc forming module using difference in flocculation velocity, motor, horizontal or vertical axis, A hybrid type of floc forming paper, which is configured by selectively combining a mechanical stirring floc forming module composed of a stirrer, has a characteristic of significantly reducing land area, floc forming time, and energy compared to the prior art.

Description

Flocculation basin for treatment of drinking water and wastewater

The present invention relates to a floculation basin for treating water and sewage water, and is a technique for forming a large floc that facilitates sedimentation by effectively colliding fine particles contained in treated water. .

In general, the characteristics of each flocculant module is characterized in that the flocculation is carried out by repeatedly attaching and detaching the microparticles to the media, detaining and releasing the medial pores in the filter flocculation module, and in the wet stirring flocculosis module, The floc grows due to the impact of particles and flocs caused by effective and variable flow rate, vortex and agitation. The collision causes a large floc, and the mechanical stirring floc forming module has a structure inducing collision between flocs by turbulence formation by a horizontal or vertical shaft stirrer mounted on a motor.

In the present invention, in forming a floculation basin (Flocculation basin), the flocculation system is formed by selectively combining the above-mentioned filtration floc forming module, storm stirring floc forming module, upward laminar floc forming module, and mechanical stirring floc forming module. And fine particles collide to form flocs according to the characteristic floculation mechanism of each floc forming module when the target object passes through the floc forming system.

In the conventional water treatment process for water supply, coagulant is administered in a rapid mixing tank to fine-flocculate colloidal microparticles, microorganisms, dissolved organic and inorganic substances. Afterwards, the floc grows large to facilitate removal by sedimentation or dissolved air flotation in the floculation basin.

In the sewage treatment process, suspended solids (SS) are first precipitated to facilitate subsequent biological treatment or finally to precipitate high concentrations of microbial flocs after biological treatment. In order to lower the phosphorus (Phosphorus) in the sewage water to ultra low concentration, as in the standard water purification process, a coagulant is administered to granulate the dissolved phosphorus into a precipitate and then remove sedimentation or perform filtration. In addition, in the advanced treatment process for reuse of sewage water treatment, biologically treated sewage effluent is additionally filtered or administered with flocculant, flocculation, precipitation, and filtration to achieve treatment target water quality.

Therefore, in order to maximize sedimentation efficiency in both water treatment and advanced wastewater treatment, it is important to form the fine particles contained in the treated water into large flocs. Flocculation is achieved by collisions between microparticles, microparticles and preformed flocs, and flocs. Impingement is achieved by stirring the water containing fine particles or flocs, and the methods of stirring include mechanical stirring and wet stirring. Mechanical agitation is accomplished by a stirring device consisting of a motor with adjustable speed, a horizontal or vertical axis, and various types of stirring vanes such as paddles, cones and screws. On the other hand, the agitation-type agitation is an agitation method based only on the flow of the water stream itself.

The main design factors for floculation basins that employ mechanical agitation are agitation strength and floc formation time. The floculation time is usually 20 to 40 minutes, and the rotational speed of floculators such as paddles is 15 to 80 cm / sec, and the average stirring strength (G value) in the floc forming paper is 10 to 100. It is a sec ^-1 range and is usually designed and operated in a manner of dividing into 3-4 stages and gradually decreasing it to the downstream. In the first stage of the floc forming paper, that is, the inlet, strong stirring is performed in order to increase the collision efficiency of the fine particles, and gentle stirring is performed in the third or fourth stage to prevent destruction of the flocs formed. In wet-type agitation, the average flow rate is 15 – 30 cm / sec.

Conventional techniques adopting mechanical or wet agitation require long flocculization times of 20 to 40 minutes, while mechanical agitation is superior in floc formation efficiency but 3-4 per series to achieve the required agitation strength. Since the motor is continuously driven, a lot of energy is consumed. In addition, in the wet-type stirring method, since the power of the water flow is used, the motor is not required, but the floc formation efficiency is low because the cross-sectional area (width and depth of water) of the water is relatively large.

Republic of Korea Patent Publication No. 10-2004-0080378 introduces a "flock forming apparatus". The floc is formed by passing the water to be treated through a water-permeable member in which a plurality of through holes of a ceramic honeycomb type are provided for the purpose of rapidly forming the floc and accelerating its growth. The opening diameter of the water through hole is in the range of 1.5 to 8.0 mm, the opening ratio is 35 to 90%, and the length of the water through hole is 500 to 2,000 mm.

However, in the prior art, since floc formation occurs by simply passing through the water to be treated only through the water passage member, there is a limit in collision efficiency between particles and it is largely insufficient to form a large floc that can increase the precipitation efficiency. Structurally, the streamline in the water through hole is a straight line that is close to laminar flow. Its mechanism is fundamentally different from the existing mechanical agitation or wet agitation, and the collision efficiency and the size of the floc formed must be structurally limited. There is this.

Korean Patent Laid-Open Publication No. 10-1999-016596 relates to a "floc forming apparatus for water purification systems", which is intended to form a floc while passing downflow into a floc forming tank filled with a particulate medium and mixing the raw water after mixing paper. The diameter of the floc and the cross-sectional area of the floc forming tank are characterized by increasing downward.

The prior art is advanced in that the floc is formed using the media, but there is a disadvantage in that the size of the floc that can be formed due to the limitation of the vortex formation and the stirring strength is limited only by the difference in the media particle diameter under the downflow.

In the conventional techniques adopting the mechanical stirring method or the wet stirring method, the required flocculation time is 20 to 40 minutes, so the area of the floc forming area and the structure are inevitably exceeded. Since three to four motors per series must be operated to obtain strength, energy consumption is very high, and in the wet-type stirring method, there is a disadvantage in that the floc formation efficiency is low because the cross-sectional area of the channel for floc formation is relatively large, so there is little chance of collision between particles. .

Therefore, there is a need for a floc forming paper that can cause the floc forming mechanism in the existing technology to occur intensively and convergently in a floc forming paper having a minimum space.

That is, the present invention minimizes energy consumption, required area and structure size by appropriately combining filtration, well stirring, laminar flow flocculation, and mechanical agitation, and has a floc forming paper which can maximize the size of the flocs formed. For the purpose of

In order to solve the problems of the prior art as described above and to achieve the above object, in the present invention, by selectively combining a filtration floc forming module, a vortex stirring floc forming module, an upward laminar floc forming module, a mechanical stirring floc forming module The floc forming system is constructed, and when the treated object passes through the floc forming system, fine particles collide according to the characteristic floculation mechanism of each floc forming module to form flocs and achieve the required floe size. To make it possible.

In the filter-type floc forming module, flocking has the advantage of repeating attachment and desorption of fine particles to the media, detention and release from the media pores. However, if the medial pore is too small, the size of floc that can be produced is small. If the medial pore is large, the size of the generated floc is slightly larger, but the attachment and desorption function is reduced, so the choice of media and the thickness of the media layer are important factors. In the specially designed flow type stirring floc forming module, it is possible to generate a change in flow velocity, vortex and agitation strength in a minimum space, thereby dramatically increasing the frequency of collision between particles and flocs. In addition, in the upward laminar flow floc forming module, collision between flocs is caused by the formation of turbulence by a horizontal or vertical shaft stirrer mounted on the motor.

In the prior art, in the present invention, a 3-4 stage reactor, 20-40 minutes of floculation time, adopted for the purpose of gradually decreasing the agitation strength to the next stage in order to increase the size of the flocs. By concentrating and concentrating with a floc forming time of about 5 to 10 minutes in the reactor, compared to the prior art, the land area and structure size can be significantly reduced, thereby greatly improving economic efficiency.

In particular, in the conventional mechanical stirring floc forming paper, the driving of 3 to 4 rotary motors and horizontal or vertical agitator is necessary per series, but according to the size of the floc to be formed, the mechanical stirring floc forming is omitted or about one. It is enough to install a mechanical stirring floc forming paper, the energy is greatly reduced.

In addition, in the conventional wet type floc forming paper, since the stirring is performed while passing through the empty space of the reaction tank only up and down or horizontally, the floc forming efficiency is low and the long floc forming time is required as described above. In addition, the number of unit-flow stir flocking modules can increase the number of particles or flocs, and the impact chance of particles or flocs can be dramatically increased.

1 is a floc forming paper in which a filtration floc forming module, a stirrer floc forming module, an upward laminar floc forming module, and a mechanical stirring floc forming module (vertical shaft, paddle flat) are arranged up and down in one reactor. example
Figure 2 is an explanatory view of the structure of the upstream unit flow type stirring floc forming module of the present invention and the vortex generation and stirring formation in the module (polyhedron type, cut pipe type)
3 is a layout view of the upstream flow type stirring floculation module configuration and unit flow type stirring floculation module according to the present invention;
Figure 4 is an explanatory view of the floc forming process in the upward laminar flow floc forming module of the present invention
5 is an example of a floc forming paper in which the floc forming module of the present invention is disposed in two stages adjacent to each other up and down and side to side;
Figure 6 is an example of a floc forming paper disposed sideways adjacent to the floc forming the flow of the floc forming module of the present invention in a horizontal flow

The present invention is to form a large and heavy flocs necessary to increase the efficiency of precipitation or filtration adopted for the treatment of colloidal microparticles, phosphorus, microorganisms, dissolved organic and inorganic substances in drinking water or sewage water, A flocculant for constant and sewage treatment, developed to achieve minimum structure size, short flocculization time, and energy savings, using flocculation agents (Rapid mixing tank or other flocculant injection facility) After rapid mixing while administering coagulant, the water to be treated is introduced into a reactor for floc formation, that is, floculation basin. Depending on the nature of the water to be treated and the target water quality, the water to be treated may be directly introduced into the floculation basin without administering a flocculant.

Details of the implementation of the present invention will be described in detail with reference to FIGS. 1 to 6. As illustrated in FIG. 1, the floc forming paper 1, which is the overall structure of the present invention, includes a filtration floc forming module 2, a wet stir floc forming module 3, an upward laminar flow floc forming module 4, and a mechanical type. It is configured by selectively combining the stirring floc forming module (5). The floculation mechanism occurring in the floc forming module has different characteristics and is arranged in accordance with the principle of making the floc gradually larger.

The filter-type floc forming module (2) includes: filter sponge, sponge, sand, anthracite, granular activated carbon, artificial lightweight yarn, polyethylene pellets, ABS resin pellets, nonwoven fabric, fiber yarn, microfiber fabric, polyester cotton, cotton wool, Composed of one or two or more of a variety of media such as microfiber, multi-layered insect screen. As in the general filter paper for water treatment, gradual breakthrough proceeds as the fine particles are attached and detached to the media surface, the detention and separation from the media pores are repeated. In the filter paper to obtain clean filtered water, backwashing is performed when the water quality decreases due to breakthrough to wash the flocs retained in the filter medium, and then perform filtration again. However, the filtered floc forming module (2) of the present invention. Is not intended to remove flocs, but to induce breakthrough while forming fine particles into flocs. Therefore, if the gap of the media is too small or the particle size of the media is too small, and the thickness of the media is too large, the loss head becomes excessive due to clogging of the void by the floc before the breakage of the floc, resulting in an increase in the height of the structure. This is undesirable.

In order to overcome this problem, the thickness of the media layer is sufficient to be about 5 to 20 cm, and in the case of upflow, the media having a small pore at the bottom of the filtration floc forming module 2 is combined with a media having a relatively large pore at the top. The arrangement may increase the adhesion efficiency of the fine particles and at the same time allow a larger floc to be formed while passing upward through the filtered floc forming module 2.

The storm stirring floculation module 3 is composed of one or more unit storm stirring floculation modules 9. As shown in FIG. 2, the unit flow type stirring floc forming module 9 has a structure in which the inflow side of the water to be treated is open and the opposite side of the inflow portion is blocked in a wall form, and the side surface (four sides when using a cube) is partially. By having a structure such as an open polyhedron or a cut pipe type, the object to be treated serves as a passage that flows to the next unit flow type stirring floc forming module 9 or the next floc forming module 4 and 5. That is, the treated object water entering the unit flow type stirring floc forming module 9 at a high flow rate at the inlet part first hits the wall and forms eddy currents, and agitation occurs in this process to cause collision between particles. It is a structure that exits through the side after the floc is formed.

As shown in FIG. 3, when the unit type stirring floc forming module 9 is composed of multiple layers, the floc forming is very effective. The gap between the unit flow type stirring floc forming module 9 of the layer into which the treated water is first introduced is narrowed and the height of the unit flow type stirring floc forming module 9 is made small, and the gap is widened to the next layer in the flow direction. By increasing the height, the actual flow rate, vortex formation degree, and agitation strength in the module of the water to be treated gradually decrease toward the rear of the flow direction, so that the generated floc is not broken as the flow progresses. The same applies to the horizontal flow floc forming module as shown in FIG. 6.

As shown in FIGS. 1 and 5, the upstream laminar flow floc forming module 4 has a predetermined distance of a vacant space in the floc forming region due to the difference in ascending speed according to the difference in the size or density of the floc as the object flows upward. It is based on the principle that the floc will increase due to the collision. The settling velocity of particles or flocs is proportional to the mass, so the larger the floc, the faster the settling velocity. In the upward laminar flow floc forming module 4 of the present invention, the rising speed of a small floc is increased and the rising speed of a large floc is slow because it flows upward. 4 shows the collision and floc formation process according to the difference in the ascending speed of the floc.

As shown in FIGS. 1, 5 and 6, the mechanical stirring floc forming module 5 has a vertical or horizontal axis connected to a speed adjustable motor, and various types of agitators including paddles are configured vertically or horizontally. . As the stirrer rotates, it induces agitation strength (G value) and collisions between particles form flocs.

The following describes the preferred combination and arrangement of the filtration floc forming module 2, the stirrer floc forming module 3, the upflow laminar floc forming module 4, and the mechanical stir floc forming module 5. As shown in FIG. First, the filtration floc forming module 2 will be described based on the floc forming mechanism. Since all the fine particles must pass through the pores in the media, the collision efficiency between the fine particles is excellent, but there is a limit to forming a very large floc due to the limitation of the pore size. Therefore, it is preferable to arrange the filtration floc forming module 2 at the first stage flowing from the mixed paper. The stirrer-type floc forming module 3 can freely adjust the size, number, number of layers and the size of the floc to be formed. (Hybrid) can be used.

Since the collision efficiency between particles is relatively low due to the flow characteristic of laminar flow, the upward laminar flow floc forming module 4 can contribute to floc formation if there is an empty space for maintaining the water level in the floc forming area. have.

Mechanical stirring floc forming module (5) is excellent in the collision efficiency between particles but consumes a lot of energy, it is preferable to arrange the minimum number in the last step. The mechanical stirring floc forming module 5 may be omitted in consideration of the sediment quality target and the flocculation characteristics.

≪ Example 1 >

The filter-type floc forming module 2 is constructed by using a filter sponge having a three-dimensional mesh structure made of polyurethane (PU) on a floc forming sheet made of acrylic having a width of 48 cm x 48 cm x 50 cm. It was. Two kinds of filter sponges, namely pore size 10 PPI (3 cm thick) (Pore per Inch, hole per inch) and 25 PPI (3 cm thick) were stacked in multiple layers to form a filter layer. In addition, a plurality of unit flow type stirring floc forming modules 9 are arranged on the filter sponge filter media layer (6 cm in total), 12 cm x 17.5 cm x 5.5 cm and 11 cm x 14.5 cm x 5.5 cm. Stacked in three stages to form a wet stirring floc forming module (3). A floc forming paper was formed by forming an upward laminar flow floc forming module 4 of 15 cm to 33 cm above the filtration floc forming module 2 or the wet stir floc forming module 3. The water to be treated was artificial artificial water using ocher, mixed with a flocculant and a coagulant (pH regulator), and mixed (Rapid mixing), and flowed into floc forming paper (1). At this time, the raw water supply flow is 64.2L / min and the flow rate of upflow of the floc forming land is 500m ³ / m ² / day. [Table 1] shows the number of floes that have passed through the mixed paper, filtered floc forming module + upflow laminar floc forming module, and filtered floc forming module + upstream stir floc forming module + upflow laminar floc forming module. The water formed was sampled for 8 minutes and the result of precipitation experiment was shown. The sediment removal rate of mixed effluent without floc formation was only 27.8%, but the sediment removal rate of the floc effluent (hybrid) effluent combined with three floc formation modules increased to 78.1% and was larger than the laboratory scale. In practice, increasing the number of layers of unit-flow stirred floc forming modules in the plant is obvious. The flocculation time (total residence time) in this experiment was only 1.44 minutes, which proved to be significantly reduced compared to the floculation time of 20-40 minutes in the prior art.

Time (min) After mixing After passing the filtered floc forming module + upflow laminar floc forming module After passing through the filtered floc forming module + flow stirring floc forming module + upward laminar flow floc forming module Turbidity (NTU) Turbidity (NTU) Turbidity (NTU) 0 12.5 10.6 10.3 One 12.5 9.17 7.58 2 12.3 7.65 7.35 3 11.5 6.74 5.99 4 11.4 5.60 5.30 5 11.1 5.47 4.39 6 10.5 5.06 3.05 7 9.06 4.92 2.97 8 9.03 4.82 2.26 8 minutes precipitation removal rate
(4cm below the surface) 27.8% 54.5% 78.1%

1: floc forming paper
2: Filtered floc forming module (combined by filter sponge, anthracite, microfiber, etc.)
3: Upstream Stir Flock Forming Module 4: Upflow Laminar Flock Forming Module
5: Mechanical Stir Flocking Module (Vertical Shaft, Paddle Type, Slow Stirring)
6: rectifying wall 7: paddle
8: support layer support structure 9: unit flow type stirring floc forming module

Claims (7)

A floc forming system is formed by forming one or two of a filtration floc forming module and a stirrer stirring floc forming module in the floc forming paper, and additionally forming an upward laminar floc forming module or a mechanical stirring floc forming module. A floc forming paper which allows the floc to gradually increase as the water passing through the forming system promotes the flocculation of the fine particles contained in the water to be treated. The method of claim 1,
The filter-type floc forming module is a filter sponge, sponge, sand, anthracite, granular activated carbon, artificial lightweight yarn, polyethylene pellets, ABS resin pellets, nonwoven fabric, fiber yarn, microfiber fabric, polyester cotton, cotton wool, ultra-fine fiber Composed of one or two or more of the media, such as a multi-layer screen, and when the treated water passes through the filter-type floc forming module, the fine particles contained in the water to be treated are repeatedly attached to and detached from the surface of the filter medium, A floc forming paper, characterized in that flocking is promoted and the floc gradually increases in size while repeating detention and escape from the media gap. The method of claim 1,
The wet stir flock forming module is composed of one or more unit wet stir flock forming modules, and the unit flow stir flock forming module is composed of a wall surface in which an inflow side of the water to be treated is opened and the opposite side of the inflow portion is blocked. The side surface is a floc forming paper, characterized in that it has a partially open structure so that the water to be treated flows into the next unit flow type stirring floc forming module or the floc forming module of the next step. The method according to claim 1 or 3,
When the water to be treated flows into the unit-type stirring floc forming module of the wet-type stirring floc-forming module, it hits the wall opposite to the inlet of the unit-type stirring floc-forming module and forms a vortex and causes stirring to cause collision between particles. A floc forming paper having a structural feature exiting the unitary agitation floc forming module through the side surface of the unitary agitation floc forming module after the formation. The method according to claim 1 or 3,
In constructing the unit flow type floc forming module of the flow type stirring floc forming module in multiple layers, the interval between the unit flow type stirring floc forming modules of the layer into which the water to be treated first flows is narrowed and the unit flow type stirring floc forming module is formed. The height is small, and the distance between the unit flow type stirring floc forming modules is increased to the next layer in the flow direction, and the height of the unit flow type stirring floc forming module is increased to increase the height of the unit flow type stirring floc forming module. A floc forming paper having structural features such that the degree of vortex formation and the stirring strength are reduced. The method of claim 1,
The upflow laminar flow floc forming module has a structural feature in which the floc grows due to a difference in ascending speed according to the difference in size or density of the floc as the object flows upward through a predetermined distance of the empty space in the floc forming region. Formation. The method of claim 1,
The mechanical stirring floc forming module is a floc forming paper, characterized in that consisting of a motor capable of adjusting the speed and the horizontal axis or vertical axis stirrer.

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