KR102012965B1 - Dissolved Air Flotation System using ambient air - Google Patents

Abstract

The present invention relates to a dissolved air flotation system using atmospheric air, and more specifically, dissolved air characterized by generating fine air using water discharged from a pump by introducing atmospheric air rather than compressed air into a front end of a pump. For the injury system. The dissolved air flotation system of the present invention can reduce the CAPEX / OPEX by using the atmospheric air instead of the compressed air without the need for a separate air compressor or service air of the system.

Description

Dissolved Air Flotation System using ambient air}

The present invention relates to a dissolved air flotation system using atmospheric air, and more specifically, dissolved air characterized by generating fine air using water discharged from a pump by introducing atmospheric air rather than compressed air into a front end of a pump. For the injury system. The dissolved air flotation system of the present invention can reduce the CAPEX / OPEX by using the atmospheric air instead of the compressed air without the need for a separate air compressor or service air of the system.

In general, suspended solids in raw water should be removed to meet water and drinking water standards in water treatment or seawater desalination. To this end, a water treatment process consisting of a mixing basin, a coagulation basin, and a floatation basin is used to remove suspended particulate matter.

In the mixing tank, the drug and raw water are rapidly mixed to agglomerate fine suspended matter first and discharged to the agglomeration tank, and in the agglomeration tank, the floating material primarily agglomerated by the mixing tank is grown to a size capable of floating separation in the flotation tank. It is discharged to the flotation tank disposed at the rear end.

Conventional flocculation tanks are provided with a separate mechanical agitator to induce flocculation through contact between the flocculant or the auxiliary flocculant and the suspended solids and to form a circulating water stream for the growth of the flocculant. In order to achieve this, the coagulation tank is generally configured in multiple stages.

On the other hand, the separation tank serves to lift and remove the aggregates grown in the flocculation tank, the fine bubbles (bubble) is attached to the suspended phase contained in the dispersion medium (disperision medium) in contact with the dispersion medium and air Float to the limit surface to induce solid-liquid separation.

The separation tank may be a dissolved air flotation method (DAF), a dispersed air flotation method (DAF), an induced air flotation method (IAF), or a method for generating microbubbles. It can be implemented in various forms such as vacuum flotation, electroflotation, and microbiological autofloatation.

Among them, the dissolved air flotation (DAF) is based on the principle that when air is sufficiently dissolved in high pressure water and introduced into the bottom of the separation tank, the supersaturated air is ejected into the micro bubbles as the high pressure water is decompressed in the water. The ejected microbubble is attached to the floc in the raw water, and the bubble-floc conjugate is reduced in specific gravity, so that the solid-liquid separation is achieved while rising from the water to the water surface by buoyancy.

At this time, some of the treated water is used as circulating water and pressurized again to form micro bubbles. Conventional dissolved air flotation devices pressurize the circulating water with a pump and saturate the pressurized water as shown in FIG. It was common to dissolve in contact with compressed air in a saturator.

However, such a system using the conventional dissolved air flotation method using compressed air requires a separate complicated air compressor facility for generating compressed air, and increases the capacity of the service air of the plant. There was a problem that it would increase the cost of CAPEX / OPEX.

Republic of Korea Patent Publication No. 2007-0064246 (Published June 20, 2007)

Disclosure of Invention The present invention is to solve the above-mentioned problems, and does not use compressed air, and does not require a separate air compressor or a service air of a system, and thus a dissolved air injury system capable of reducing CAPEX / OPEX. To provide.

In order to achieve the above object, an embodiment of the present invention, a flocculation unit 100 for mixing and forming a floc (floc) by mixing the raw water (raw water) and flocculant; A microbubble is introduced through a nozzle provided at the bottom, and the separation unit 200 floats the floc to the water while removing the microbubble attached to the floc; In the dissolved air floatation (Dissolved Air Flotation, DAF) system comprising a; and the circulation water supply line 300 The pump 310 is formed to pressurize the circulating water supplied into the separation unit 200, and provides the dissolved air flotation system, characterized in that atmospheric air is introduced into the front of the pump (310).

An air flow meter and a valve for adjusting the air flow rate are preferably installed in the inlet pipe for introducing the atmospheric air, and a stabilizer 320 for dissolving the undissolved bubbles in the circulating water is provided at the rear end of the pump 310. Is preferably formed. The circulating water may include raw water or raw water mixed with a flocculant.

In addition, the separation unit 200 includes a plurality of floating tanks arranged in series in the flow direction of the raw water, neighboring floating tanks are partitioned by the partition wall 230, the raw water is along the passage formed under the partition wall It may be implemented in the form of moving to the neighbor floating flotation. At this time, it is preferable that an adjustable weir 231 is formed to pass a scum that floats on the partition 230 to a neighboring float.

In addition, a guide wall 240 is formed at the bottom of the flotation tank to float the microbubble upwards, and the microbubbles are introduced into the front and rear portions of the flotation vessel partitioned by the guide wall 240, respectively. .

In one embodiment, the separation unit 200, the primary flotation tank 210 is made of flocculation and flotation at the same time; And a secondary flotation tank 220 which floats and removes the floc again included in the treated water passing through the primary flotation tank 210.

At this time, the circulating water containing the raw water is introduced into the primary flotation tank 210, and the circulating water containing the treated water is introduced into the secondary flotation tank 210.

On the other hand, the agglomeration unit 100 is composed of a single agglomeration tank, the turbulence-forming derivative 111 is filled in the inner space is preferably a non-power flocculation tank for generating turbulence.

The agglomeration part 100 may include: a first mixed agglomeration part 110 generating high-speed turbulence to form flocs primarily in the raw water introduced by filling the first turbulence-forming derivative 111 in the inner space; And a second turbulence-forming derivative 121 filled in an inner space to generate slow turbulence at a lower speed than the first mixed agglomerate for secondarily growing flocs in the raw water passing through the first mixed agglomerate. It may include; 2 mixed agglomeration unit 120.

In addition, in order to maintain a different turbulence intensity between the first and second mixed agglomerates 110 and 120, the porous portion partitioning the first and second agglomerated parts 110 and 120. Separation membrane 130; may further include.

In this case, the first mixed condensing unit 110 is provided in the upper side region of the second mixed condensing unit 120, and the raw water passing through the first mixed condensing unit 110 is gravity-condensed by the second mixed condensing unit 110. It may be supplied to the unit 120.

The first turbulence-forming derivative 111 may be a multi-layered mesh type material or a plurality of fiber bundles intertwined with each other, and the second turbulence-forming derivative 121 may include a plurality of falling rings. ) Material may be used.

In addition, the second mixed agglomerating unit 120 may be provided with a plurality of stages in which the polling-type material is filled and separated from each other, and the plurality of stages may be disposed downstream of the polling-type material. It is preferable that the packing density is provided to be small.

Since the dissolved air flotation system of the present invention does not use compressed air, there is no need for a separate air compressor or service air of the system, thereby reducing CAPEX / OPEX.

In addition, by using the raw water as the circulating water to improve the treatment efficiency of the raw water, by minimizing the flocculation tank and equipped with a multi-stage flotation tank can reduce the installation area and increase the separation efficiency to maximize the water treatment efficiency.

1 is a schematic diagram showing the operation principle of a conventional dissolved air flotation system.
2 and 3 is a schematic diagram showing the operating principle of the dissolved air flotation system according to an embodiment of the present invention.
4 and 5 is a schematic diagram showing a non-motor hybridization coagulation tank according to an embodiment of the present invention.

Before describing in detail through the preferred embodiments of the present invention, the terms or words used in the present specification and claims should not be construed as being limited to the conventional or dictionary meanings, meanings corresponding to the technical spirit of the present invention To be interpreted as

Throughout this specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless otherwise stated.

Dissolved air flotation system of the present invention is a flocculation unit (100) for mixing and forming a floc (floc) by mixing the raw water (raw water) and flocculant; A microbubble is introduced through a nozzle provided at the bottom, and the separation unit 200 floats the floc to the water while removing the microbubble attached to the floc; And a circulating water supply line 300 for supplying circulating water in which the air is dissolved into the separation unit 200. In the dissolved air floatation (DAF) system, as shown in FIG. A pump 310 is formed in the circulation water supply line 300 to pressurize the circulation water supplied into the separator 200, and atmospheric air is introduced into the front of the pump 310.

In conventional dissolved air flotation systems, it is common to pressurize the circulating water with a pump and then contact the pressurized water with compressed air in a saturator to dissolve the compressed air. However, such a system using compressed air requires a separate complicated air compressor facility for generating compressed air and increases the capacity of the service air of the plant, thereby increasing the CAPEX / OPEX cost. There was a problem.

In order to solve this problem, the present invention by introducing the air in the front end of the pump 310 to pressurize the circulating water instead of using the compressed air so that the pressurization of the circulating water in the pump and the dissolution of the air in the circulating water at the same time Characterized in that.

In the present invention, since pressurization of the circulating water and dissolution of air are simultaneously performed in the pump, separate compressed air is not required, and an air flow meter and a valve are separately installed in an inlet pipe for introducing the air. By controlling, it is possible to minimize cavitation or abnormal fluid phenomenon that may occur in the pump.

On the other hand, conventionally, in order to dissolve compressed air in pressurized circulating water, a large-capacity saturator that fills a packing material or forms a structure to increase the internal surface area is generally used. However, the present invention is characterized in that it is not necessary to use a large-capacity saturation apparatus as in the prior art because the air is dissolved in the pump.

However, due to short retention time and air fluctuation in the pump, undissolved bubbles may be formed in the circulating water. In order to re-dissolve, it is preferable that a separate stabilizer 320 is formed at the rear end of the pump 310.

The stabilizer 320 is intended to completely dissolve into the pressurized circulating water while the undissolved bubbles in the circulating water are agglomerated and divided with each other, and the equipment and capacity are much reduced compared to the existing saturation apparatus.

On the other hand, conventionally, treated water (production water) in which water treatment is completed is used as circulating water. That is, since the treated water continues to occupy a part of the water treatment capacity (which occupies 10-20 vol% of the total water treatment capacity) while circulating the floating tanks, this results in a reduction in the capacity of the raw water that can be treated and a decrease in water treatment efficiency. It became.

However, in order to solve this problem, using raw water that has not been treated as circulating water causes another problem that raw water passes through the saturation device to generate biofouling, thereby reducing saturation efficiency and lowering water treatment efficiency.

In other words, the use of raw water as circulating water causes biofouling problems due to the formation of microorganisms in the filling material inside the saturation device, which is more deadly in the case of a saturation device composed of a high pressure and large volume pressure vessel.

As described above, the present invention does not use a large-capacity saturation device having a large volume, and circulates the raw water or raw water mixed with coagulant as much as using the stabilizer 320, which is much smaller in size and capacity than the existing saturation device. It can also be used to minimize biofouling problems.

On the other hand, when using the raw water as the circulating water as described above can be obtained the effect of increasing the water treatment capacity, while the raw water that does not pass through the flocculation unit 100 directly into the separation unit 200 as much as raw water Insufficient formation and growth of flocs can reduce water treatment efficiency.

Thus, in the present invention, the separation part 200 is configured to include a plurality of floating tanks arranged in series in the flow direction of the raw water instead of one floating tank as in the prior art, so that the formation and growth of flocs in the floating tank is sufficient. Can be done.

In more detail, as shown in FIG. 3, the plurality of floating flocks are partitioned by the partition wall 230, but the raw water moves to the adjacent floating flocks along a passage formed under the partition wall. Can be implemented.

At this time, the scum that floats in the floating tank of the front end portion may be separated and removed through the skimmer, but preferably the scum that floats without installing a separate skimmer as shown in FIG. 3. It is efficient to form an adjustable weir (231) for passing over to the neighboring flotation tank so that it can be separated and removed through the skimmer at the final flotation tank.

In addition, each floating tank bottom is formed with a guide wall 240 for floating the microbubble upwards, conventionally it was common that the microbubble flows only in the front portion of the guide wall as shown in FIG. That is, as the microbubble sprayed from the bottom surface of the front wall of the guide wall rises upward along the guide wall 240, the floc in the raw water floats on the surface of the water, wherein the raw water on the rear surface of the rear surface of the guide wall 240 is relatively The chance of contacting the microbubble is reduced so that the separation and removal efficiency of the flocs that do not contact the microbubble on the front side is inferior.

In the present invention, as shown in FIGS. 2 and 3, the microbubbles are separately introduced into the front and rear portions of the flotation tank partitioned by the guide wall 240, so as to contact the microbubbles at the front of the guide wall 240. Flocks that do not have a feature of improving the separation and removal efficiency of the flocs by allowing the back wall of the guide wall 240 to sufficiently contact the microbubbles again.

The number of floating tanks constituting the separation unit 200 may be variously modified according to an application situation, but in one embodiment, a primary flotation tank 210 in which flocculation and flotation are simultaneously performed; And a secondary flotation tank 220 for again injuring and removing the floc included in the treated water that has passed through the primary flotation tank 210.

At this time, the circulating water flowing into the primary flotation tank 210 and the secondary flotation tank 220 may be variously used, such as treated water, raw water or raw water into which flocculant is injected, preferably raw water used as circulating water. In order to increase the treatment efficiency of the flotation, flocculation and flotation of the flotation and the flotation water containing the raw water or the flocculant is introduced into the primary flotation 210 is mainly included in the treated water passed through the primary flotation It is preferable that the circulating water including the treated water flows into the secondary flotation tank 210 which floats and removes the floc again.

On the other hand, when the separation unit 200 is configured as a plurality of flotation tanks as described above, flocculation and growth of the floc is also made in the flotation tank, it is conventionally composed of a multi-stage agglomeration unit (agitator) is installed ( The configuration of 100) can be minimized.

In one embodiment, the agglomeration part 100 of the present invention is composed of a single agglomeration tank, preferably a non-motor to generate turbulence by filling the turbulence-forming derivative 111 in the inner space to replace the function of the conventional mechanical mixing coagulation tank Agglomeration bath can be used.

More preferably, the agglomeration part 100 is a first turbulence-forming derivative 111 is filled in the inner space as shown in FIG. The first mixed condensing part 110 and the second turbulence-forming derivative 121 are filled in the inner space, and the second mixed condensing part is lower than the first mixed condensing part for growing flocs in the raw water passing through the first mixed condensing part. It may be configured to include a second mixed agglomeration unit 120 for generating a slow turbulence of the speed.

Through such a configuration, the fine particles contained in the raw water are circulated in the inside by the turbulent flow without any additional stirring power, and can be brought into contact with the coagulant to aggregate to a certain size.

In addition, in order to maintain a different turbulence intensity between the first and second mixed agglomerates 110 and 120, the porous portion partitioning the first and second agglomerated parts 110 and 120. The separator 130 may be further provided.

In this case, the first mixed condensing unit 110 is provided in the upper side region of the second mixed condensing unit 120, and the raw water passing through the first mixed condensing unit 110 is gravity-condensed by the second mixed condensing unit 110. It is preferable to be supplied to the part 120.

Looking at the operation of the non-power flocculation tank in detail, the raw water flowing in the form of a straight stream through the inlet pipe passes through the first turbulence-forming derivative 111 filled in the first mixed flocculation unit 110 to form a rapid turbulent flow Due to the generated turbulence, flocs are formed as the fine particles and coagulant contained in the raw water come into contact with each other. The first turbulence forming derivative 111 may be formed in which a plurality of mesh-type materials are stacked or a plurality of fiber bundles are entangled with each other. Preferably, holes are formed between adjacent mesh-type materials. It can be stacked asymmetrically so that they do not coincide in the vertical direction.

Since holes between the mesh-type materials are stacked asymmetrically in the vertical direction, raw water may generate turbulence while passing through the mesh-type material by gravity, and control the speed of turbulence generated according to the size of the hole. .

The second mixed condensing unit 120 may grow flocs included in the raw water due to the slow turbulence generated while the treated water passing through the first mixed condensing unit 110 passes through the second turbulence forming derivative 121. Space.

The second turbulence-forming derivative 121 may be a form filled with a plurality of Fall Ring-type materials, preferably a plurality of forms in which the stages in which the plurality of Fall-type materials are filled are separated from each other. It may be in a stacked form.

FIG. 5 is a schematic view showing a state in which polling-type filled materials are stacked in a plurality of tiers, and the second mixed agglomeration part 120 of the present invention is filled with polling-type material according to the state of raw water. The number of stages may be controlled and used, and the plurality of stages may be separated so that the packing density becomes smaller toward the downstream region. As the packing density decreases, the turbulence speed decreases. Because you can grow flocs into bigger chunks.

On the other hand, the separation membrane 130 is a separation membrane that partitions the first mixed agglomeration unit 110 and the second mixed agglomeration unit 120, between the first mixed agglomeration unit 110 and the second mixed agglomeration unit 120. Partition to maintain different turbulent velocities. The first mixed agglomeration unit 110 generates rapid turbulence, and the second mixed agglomerated unit 120 generates slow turbulence to agglomerate fine particles contained in the raw water to form and grow flocs. It is not particularly limited and may be defined as a relative difference in turbulence intensity in the mixed flocculation tank.

The present invention is not limited to the above specific embodiments and descriptions, and various modifications can be made by those skilled in the art without departing from the gist of the invention as claimed in the claims. Such variations are within the protection scope of the present invention.

100: agglomeration part 110: first mixed agglomeration part
111: first turbulence forming derivative 120: second mixed aggregate
121: second turbulence forming derivative 130: membrane
200: separating portion 210: primary flotation tank
220: secondary flotation 230: bulkhead
231: height adjustment wear 240: guide wall
300: circulating water supply line 310: pump
320: stabilizer

Claims (14)

An agglomeration part 100 for mixing raw water and a flocculant to form and grow flocs; A microbubble is introduced through the nozzle provided at the bottom, and the separation unit 200 floats the floc to the water while removing the microbubble attached to the floc; In the dissolved air floating (Dissolved Air Flotation, DAF) system comprising a; and a circulation water supply line 300 for supplying the circulation water dissolved air into the separation unit 200,
A pump 310 is formed in the circulation water supply line 300 to pressurize the circulation water supplied into the separation unit 200, and atmospheric air flows into the front of the pump 310 to allow the pump 310 to flow in the pump 310. Joining the circulating water and dissolving the air in the circulating water
The coalescing unit 100 is a non-powered coalescing unit,
A first mixed condensing part 110 generating high-speed turbulence to form flocs primarily in the raw water introduced by filling the first turbulence-forming derivative 111 in the inner space;
A second turbulent derivative 121 is filled in the inner space to generate slow turbulence at a lower speed than the first mixed flocculator for growing flocs secondary to the raw water passing through the first mixed flocculator; Misclumping unit 120; And
Porous separator partitioning the first and second mixed agglomerates 110 and 120 to maintain different turbulence intensity between the first and second mixed agglomerators 110 and 120. 130;
The first mixed condensing part 110 is provided in an upper side region of the second mixed condensing part 120, and the raw water passing through the first mixed condensing part 110 is moved by gravity to the second mixed condensing part ( 120)
The first turbulence-forming derivative 111 is a multi-layered mesh type material, which is asymmetrically stacked so that holes do not coincide in a vertical direction between materials of adjacent mesh types.
The separation unit 200,
It includes a plurality of flotation tanks arranged in series in the flow direction of the raw water,
The neighboring flotations are partitioned by the partition wall 230, and the raw water moves to the neighboring flotation along the passage formed at the bottom of the partition wall,
On the top of the partition 230, an adjustable weir 231 is formed to pass an injured scum to a neighboring float.
A guide wall 240 is formed at the bottom of the float to float microbubbles upward.
Microbubbles are respectively introduced to the front and rear portions of the floating tank partitioned by the guide wall 240,
The upper end of the guide wall 240 is formed to be bent in the moving direction of the raw water to prevent the micro-bubbles supplied to the rear portion of the guide wall 240 to move to the front portion, the micro-bubbles supplied to the front portion with the raw water Dissolved air floating system, characterized in that to move to the rear portion. The method of claim 1,
Dissolved air flotation system, characterized in that a valve for adjusting the air flow meter and air flow rate is installed in the inlet pipe for introducing the air air. The method of claim 1,
Dissolved air flotation system, characterized in that the stabilizer 320 for dissolving the undissolved bubbles in the circulating water is formed at the rear end of the pump (310). The method of claim 1,
Dissolved air flotation system, characterized in that the circulating water comprises raw water or raw water mixed with a flocculant. delete delete delete The method of claim 1,
The separation unit 200,
Primary flotation tank 210 is made of flocculation and flotation at the same time; And
A secondary flotation tank 220 for again injuring and removing flocs included in the treated water passing through the primary flotation tank 210;
Dissolved air flotation system comprising a. The method of claim 8,
Circulating water containing raw water is introduced into the primary flotation tank 210,
Dissolved air injury system, characterized in that the circulation water containing the treated water flows into the secondary flotation tank (220). delete delete The method of claim 1,
The second turbulence-forming derivative (121) is a dissolved air flotation system, characterized in that a plurality of (Pall Ring) type of material. The method of claim 12,
The second mixed condensation unit (120) is a dissolved air flotation system, characterized in that provided with a plurality of stages (stage) of the form filled with the polling type is separated from each other. The method of claim 13,
And a plurality of stages are provided such that packing density of the polling type material becomes smaller toward the downstream side.

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