KR20210117421A - Water treatment apparatus using dissolved air flotation capable of responding to fluctuations in flow - Google Patents

Abstract

The present invention relates to a water treatment apparatus using flotation of dissolved air capable of responding to fluctuations in a flow, comprising: a flotation tank receiving raw water passing through a coagulation tank and a flocculation tank and discharging treated water, from which contaminants contained in the raw water are flotation-separated, to a lower part by microbubbles injected into the raw water through a nozzle installed therein; and a retention tank into which the treated water flowing out from the flotation tank flows. The flotation tank includes a bubble bed formation guide extending inward from the inner wall disposed on a retention tank side to be spaced apart from the bottom. According to the present invention, a bubble bed buffer is stably maintained without changing the size of the existing equipment despite an increase in a hydraulic load factor due to an increasing inflow flow, thereby providing effects of preventing a bubble-floc polymer that has not been separated by flotation from flowing out as it is, not requiring a design change of a contact area and floating area for stabilization of a bubble bed layer, and maximizing flotation separation efficiency.

Description

Dissolved air flotation capable of responding to fluctuations in flow

The present invention relates to a dissolved air flotation oil-water treatment device, and more particularly, in spite of an increase in a hydraulic load factor according to an increasing inflow flow rate, without changing the size of an existing facility, stably maintaining a bubble bed buffer (Bubble Bed Buffer) It relates to a dissolved air floating oil water treatment device capable of responding to flow rate fluctuations.

In general, dissolved air flotation (Dissolved Air Flotation) dissolves air in water at a high pressure of 5 bar or more and sprays it on raw water flowing from the contact area in the tank through a nozzle, and the supersaturated water is reduced in pressure at atmospheric pressure. At this time, the generated microbubbles are combined with oil particles or aggregated flocs in the raw water in the contact area of the flotation tank and float, and solid-liquid separation is made and processed in the separation area of the flotation tank. The types of these oil-water separators are as shown in Table 1 below.

division API CPI IAF / IGF DAF / DGF oil form non-aqueous oil non-aqueous oil emulsion oil
water soluble oil emulsion oil
water soluble oil segregated particles

이상150

more 60

more 30

more 20

more Separation method Injury treatment by specific gravity difference Injury treatment by specific gravity difference Bubbling/floating after coagulant injection Bubbling/floating after coagulant injection

This technology is a process of removing oil having a particle size of 20 μm or more after the primary treatment of treating oil having a particle size of 60 to 150 μm or more, such as API, CPI, etc. in the oil-water treatment process. It is spotlighted as the best alternative process in areas with high number of guarantees and in areas with a small site area. The flotation process is known to be effective not only for oil removal but also for raw water with low turbidity, color, phosphorus, and humus.

Referring to FIG. 1, the flotation tank of the oil water treatment apparatus using the conventional dissolved air flotation method has a contact area, which is an area where raw water introduced into the inside and microbubbles contact, a separation area formed on the upper part of the rear end of the contact area, and a lower side thereof. divided into the outflow area of The separation zone is a zone where microbubbles and raw water collide in the contact zone, and the floating floc-microbubble polymer floats to the water surface in a turbulent state and is separated by flotation in a laminar flow state. When the inflow flow rate fluctuates, the hydraulic load factor changes due to the flow rate fluctuating in the separation region. As the flow rate increases, the hydraulic load factor increases. There is a problem in that the unsatisfactory bubble-floc polymer flows out as it is.

Usually, when designing the separation area, if the size of the generated microbubbles is smaller than the appropriate range, the rising force and speed of the bubble-floc polymer become small, so a relatively large separation area is required. However, since the efficiency of flotation separation is lowered, an appropriate design is required. In particular, when the inflow flow increases, the hydraulic load factor increases, and the bubble bed cannot withstand the inflow flow and collapse occurs. The problem is that it could be.

As a prior art for an air-floating oil-water treatment device, Korean Patent No. 10-1707776, "a wastewater treatment device using a flotation separation method of sludge" has been proposed, which mixes a coagulant with the incoming wastewater to generate flocs, a floc generating unit for growing flocs in wastewater by stirring; an ascending flow unit for rising the wastewater introduced from the flock generating unit; a bubble injection unit for attaching bubbles to the flocs of the wastewater rising by injecting bubbles into the rising flow unit; a sludge part upper part communicating with the upper part of the upward flow part so that the wastewater flows together with the flocs in contact with the bubbles, and the flocs in contact with the bubbles float to the water surface by buoyancy to form a sludge layer; a sludge discharge unit installed on one side of the sludge unit to discharge the collected sludge; and a floating sludge collecting device that collects sludge floating on the water surface of the upper part of the sludge and puts it in the sludge discharge part, wherein the rising flow part and the sludge discharge part are installed on the upper part of the sludge at a predetermined distance and the floating While the wing member of the sludge collecting device moves along the water surface from the rising flow side to the sludge discharge unit, the floating sludge is pushed and dropped into the sludge discharge unit, and the sludge discharge unit is fixed to the lower portion of the rising flow unit in water. A flow guide plate extending for a predetermined length toward By forming a flow pattern that flows in the downward direction and flows along the upper surface of the flow guide plate, the flocs that descend with the wastewater are caught on the step, and the side wall of the sludge upper part or the flow guide plate has the step on the step. A flock suction port for sucking and discharging the caught and collected flocks is installed.

However, in this prior art, a flow guide plate to catch the flow of the flow is presented, but as the flow rate increases, the hydraulic load factor increases. It is possible to solve the problem that the unsatisfactory bubble-floc polymer flows out as it is, and when the inflow flow is increased, the hydraulic load factor increases, and the problem that the bubble bed cannot withstand the inflow flow still cannot be solved.

In order to solve the problems of the prior art as described above, the present invention is to stably maintain the bubble bed buffer without changing the size of the existing equipment, despite the increase in the hydraulic load factor according to the increasing inflow flow rate. By doing so, the purpose of this is to prevent the bubble-floc polymer that has not been flotation-separated from flowing out as it is, and to maximize the flotation efficiency without requiring a change design of the contact area and the flotation area for stabilizing the bubble bed layer.

Other objects of the present invention will be easily understood through the description of the following embodiments.

In order to achieve the above object, according to one aspect of the present invention, raw water that has passed through a coagulation tank and a flocculation tank is introduced, and is injected into the raw water introduced through a nozzle installed therein. a flotation tank in which the treated water from which the contaminants contained in the raw water are flotation-separated by microbubbles is discharged to the lower part; and a retention tank into which the treated water flowing out of the floating tank is introduced, wherein the floating tank extends inward from an inner wall located on the retention tank side, thereby being spaced apart from the bottom surface of the bubble bed formation guide (Bubble bed formation guide) ) is provided, a dissolved air floating oil water treatment device capable of responding to flow rate fluctuations is provided.

The bubble bed forming guide is installed so as to ascend and descend from the inner wall of the flotation tank, so that the height can be adjusted, and the front and rear lengths are variable along the direction extending inward, and the flow rate of the raw water flowing into the flotation tank Accordingly, the height and the front and rear length may be adjusted.

The bubble bed forming guide may include: a fixed guide installed to ascend and descend along the inner wall of the floating tank; a guide elevating drive unit to enable height adjustment by allowing the fixed guide to elevate along the inner wall of the buoyant tank; a variable guide movably installed in the fixed guide in a direction extending inward; and a length adjustment driving unit for adjusting the length by moving the variable guide from the fixed guide, wherein the guide elevating driving unit and the length adjustment driving unit include, a flow rate sensor for measuring the flow rate of raw water flowing into the floating tank. It may be controlled by receiving a control signal from a control unit receiving the signal.

The flotation tank includes a contact area that allows contaminants included in the raw water to collide with each other by microbubbles injected into the raw water flowing through a nozzle installed therein, and the bubble generated by the collision-floc polymer is solid-liquid separation A baffle is provided so as to be located between the separation areas, and the baffle is installed so that the vertical length is adjusted from the bottom of the flotation tank, and the vertical length can be adjusted according to the flow rate of raw water flowing into the flotation tank. .

The baffle is a fixed baffle that is vertically installed on the bottom surface of the floating tank; a variable baffle that is movably installed on the fixed baffle in a vertical direction; and a baffle elevating driving unit for allowing the variable baffle to be raised and lowered from the fixed baffle, wherein the baffle elevating driving unit is a control signal of a control unit receiving a detection signal from a flow rate sensor that measures the flow rate of raw water flowing into the floating tank can be received and controlled.

According to the dissolved air floating water treatment device capable of responding to flow rate fluctuations according to the present invention, the bubble bed buffer is stably maintained without changing the size of the existing equipment despite the increase in the hydraulic load factor due to the increasing inflow flow rate By doing so, it is possible to prevent the bubble-floc polymer that has not been flotation-separated from flowing out as it is, and it is not necessary to change the design of the contact region and flotation region for stabilization of the bubble bed layer, and the effect of maximizing the flotation separation efficiency is achieved. have

1 is a cross-sectional view showing a flotation tank of an oil-water treatment apparatus using a dissolved air flotation method according to the prior art.
Figure 2 is a cross-sectional view showing a dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention.
Figure 3 is a cross-sectional view for explaining the operation of the dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention, compared to Figure 2, shows a case in which the flow rate of the incoming raw water is twice.
Figure 4 is a cross-sectional view for explaining the operation of the dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention, compared to Figure 2, shows a case in which the flow rate of the incoming raw water is three times.
5 is a view for explaining the operation of the dissolved air floating oil water treatment apparatus capable of responding to a flow rate fluctuation according to the present invention according to the flow rate of raw water, as in FIGS. 2 to 4 .
Figure 6 is an image for explaining the action of the bubble bed formation guide in the dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention by CFD analysis.
7 is an image for comparing and explaining the action of the bubble bed formation guide of the dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention in the absence (a) and in the presence (b). .

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it should be understood as including all changes, equivalents or substitutes included in the spirit and scope of the present invention, and may be modified in various other forms. and the scope of the present invention is not limited to the following examples.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings, and the same reference numerals are assigned to the same or corresponding components regardless of reference numerals, and redundant description thereof will be omitted.

2 is a cross-sectional view showing a dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention, and FIG. 3 is a dissolved air floating oil water treatment apparatus capable of responding to flow rate fluctuations according to an embodiment of the present invention. As a cross-sectional view for explaining the operation of, as compared to FIG. 2, it shows a case where the flow rate of the incoming raw water is double, and FIG. 4 is an operation of a dissolved air floating water treatment device capable of responding to flow rate fluctuations according to an embodiment of the present invention As a cross-sectional view for explaining the, compared to Figure 2, it shows a case where the flow rate of the incoming raw water is three times.

2 to 4, the dissolved air flotation oil water treatment apparatus 100 capable of responding to flow rate fluctuations according to an embodiment of the present invention includes a flotation tank 110 and a retention tank 120, and a flotation tank ( The bubble bed forming guide 130 is provided at 110 .

The flotation tank 110 introduces raw water that has passed through a coagulation tank and a flocculation tank, and pollutants contained in the raw water by microbubbles sprayed into the raw water flowing through the nozzle 113 installed therein. This flotation-separated treated water flows out to the lower part. The flotation tank 110 may be provided with an inlet 111 so that raw water flows in on one side, and an outlet 112 may be provided on the opposite side so that raw water is discharged. The inlet 111 is connected to the coagulation tank and the coagulation tank, so that raw water passing through them can be introduced. The floating tank 110 is connected to the retention tank 120 through the outlet 112 , so that the treated water can move toward the retention tank 120 .

A floating sludge collecting unit 160 may be provided on the upper side of the floating tank 110 . The floating sludge collecting unit 160 collects the sludge located on the upper side of the floating tank 110 by the caterpillar motion of a belt conveyor having a plurality of diaphragms or pockets in the collecting tank 161 on one side and transports or collects to the outside. can make it happen

The retention tank 120 may be configured to allow the treated water flowing out from the floating tank 110 to flow in, and to discharge the introduced treated water to the outside along a predetermined path, and a collecting tank 161 may be provided at the upper part. .

The bubble bed forming guide 130 extends inward from the inner wall located on the retention tank 120 side in the floating tank 110, and is positioned so as to be spaced apart from the bottom surface.

The bubble bed forming guide 130 is installed so as to ascend and descend from the inner wall of the floating tank 110 so that the height (B) can be adjusted, and the front and rear length (C) is variable along the direction extending inward, The height (B) and the front and rear length (C) can be adjusted according to the flow rate of raw water flowing into the flotation tank 110 .

The bubble bed forming guide 130 has a fixed guide 131 installed to ascend and descend along the inner wall of the floating tank 110, and the fixed guide 131 is raised and lowered along the inner wall of the floating tank 110 to raise and lower the height (B) A guide elevating driving unit 132 that enables adjustment, a variable guide 133 movably installed in the fixed guide 131 in a direction extending inwardly of the floating tank 110, and a variable guide 133 are It may include a length adjustment driving unit 134 for adjusting the front and rear length (C) by moving from the fixed guide (131).

The fixed guide 131 is lifted by the guide elevating driving unit 132 and may be guided so as to be elevated by a guide member such as a sliding rail or a guide vertical shaft. The variable guide 133 may be installed to be slidable in a horizontal direction by a sliding coupling structure or a guide horizontal axis from the fixed guide 131 .

The guide lift driving unit 132 and the length adjustment driving unit 134 receive a control signal from the control unit 150 that receives the detection signal of the flow sensor 151 for measuring the flow rate of raw water flowing into the flotation tank 110 and control it For example, it may be a cylinder that is connected to the fixed guide 131 or the variable guide 133 and driven by hydraulic pressure or pneumatic pressure, or the driving force of the rotary motor or the linear motor is applied to the fixed guide 131 or the variable guide ( 133) may be configured to provide a reciprocating driving force to each. At this time, the guide elevating driving unit 132 and the length adjustment driving unit 134 may be airtight or similar processing to avoid contact with raw water.

The control unit 150 controls not only the height (B), the front and rear length (C) of the bubble bed forming guide 130 according to the flow rate of raw water measured by the flow rate sensor 151, but also the vertical length of the baffle 140, which will be described later. It is possible to control the guide elevating driving unit 132 and the length adjusting driving unit 134 and the baffle elevating driving unit 143 to be described later so that (A) has an optimal value obtained experimentally.

The flotation tank 110 is provided with a baffle (Baffle; 140), the baffle 140 is included in the raw water by the microbubbles injected into the raw water flowing through the nozzle 113 installed in the inside of the flotation tank 110. It is located between the contact region 114 allowing contaminants to collide with each other and the separation region 115 in which the bubble-floc polymer generated by the collision is solid-liquid separated.

The baffle 140 may be installed so that the vertical length A from the bottom of the floating tank 110 is adjusted, and the vertical length A may be adjusted according to the flow rate of raw water flowing into the floating tank 110 .

The baffle 140 is a fixed baffle 141 installed vertically on the bottom surface of the floating tank 110, a variable baffle 142 that is movably installed in a vertical direction to the fixed baffle 141, and a variable baffle 142 ) may include a baffle elevating driving unit 143 for elevating from the fixed baffle 141.

The variable baffle 142 may be installed vertically so as to be inserted into the fixed baffle 141 to vertically slide, for example, as in this embodiment. The baffle elevating driving unit 143 may be controlled by receiving a control signal from the control unit 150 that receives the detection signal of the flow sensor 151 for measuring the flow rate of raw water flowing into the floating tank 110, for example, variable It may be configured as a cylinder connected to the baffle 142 and driven by hydraulic pressure or pneumatic pressure, or may be configured to provide a driving force of a rotary motor or a linear motor as a reciprocating driving force to the variable baffle 142 . At this time, the baffle elevating driving unit 143 may be made airtight or similar processing to avoid contact with raw water.

The operation of the dissolved air floating oil water treatment apparatus capable of responding to the flow rate fluctuation according to the present invention will be described.

First, in the separation zone 115 in the flotation tank 110, the collision of microbubbles and raw water occurs in the contact zone 114, and the floating floc-microbubble polymer floats to the water surface in a turbulent flow state and is separated by flotation in a laminar flow state. . At this time, when the flow rate of the raw water flowing into the flotation tank 110 fluctuates, the hydraulic load factor changes due to the flow rate fluctuating in the separation region 115. As the flow rate increases, the hydraulic load factor increases, and accordingly, the separation region ( 115), the turbulent flow cannot be changed to the laminar flow state, and the bubble-floc polymer that is not flotation-separated can flow out as it is. This problem is solved by the bubble bed formation guide 130 .

Usually, when designing the separation region, when the size of the generated microbubbles is smaller than the appropriate range, the rising force and speed of the bubble-floc polymer become small, so a relatively large separation region 115 is required. Although the separation region 115 is required, by the bubble bed formation guide 130, it is possible to maintain a state of excellent flotation separation efficiency without such a design change. In particular, when the inflow flow rate increases, the hydraulic load factor rises and the bubble bed collapses without being able to withstand the inflow flow rate, so that the bubble-floc polymer that has not been flotation-separated can flow out as it is. can be resolved by That is, the formation of the bubble bed serves as a buffer to prevent the agglomerated flocs from easily flowing out. It is the role of the bubble bed forming guide 130 to form a stable bubble bed in a short time.

In addition, when the flow velocity of the flow passage passing from the contact region 114 to the separation region 115 increases as the flow rate increases, a turbulent flow, not a laminar flow, occurs in the upper portion of the separation region 115 . In this case, the flock-bubble polymer cannot be separated from solid-liquid and flows out along the wall. Therefore, the height of the baffle 140 is automatically adjusted according to the flow rate of raw water flowing into the flotation tank 110 , thereby helping to form a stable bubble bed in the separation area 115 .

Referring to FIG. 6 , it can be confirmed that the bubble bed is formed and maintained by the bubble bed formation guide 130 by CFD analysis. Also, referring to FIG. 7 , when the bubble bed forming guide 130 is not present (a), when the hydraulic load increases, the water flow speed in the floating zone increases, and the bubble bed collapses along the wall with bubbles and flocs (Floats). ) is leaking. In addition, when the bubble bed formation guide 130 is present (b), the bubble bed can be maintained, and it can be confirmed that bubbles and flocs do not flow out toward the outlet.

According to the dissolved air flotation oil water treatment apparatus capable of responding to flow rate fluctuations according to the present invention, as shown in FIG. 5, by the bubble bed forming guide of variable height and front and rear length and the baffle of variable vertical length, the inflow rate is increased. By stably maintaining the bubble bed buffer without changing the size of the existing equipment despite the increase in the hydraulic load factor, it is possible to prevent the bubble-floc polymer that has not been flotation-separated from flowing out as it is, and the bubble bed It does not require a change design of the contact area and the floating area for layer stabilization, and has the effect of maximizing the flotation separation efficiency.

As described above, the present invention has been described with reference to the accompanying drawings, but it goes without saying that various modifications and variations may be made within the scope without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the following claims as well as the claims and equivalents.

110: floating tank 111: inlet
112: outlet 113: nozzle
114: contact area 115: separation area
120: retention tank 130: bubble bed formation guide
131: fixed guide 132: guide elevating drive part
133: variable guide 134: length adjustment driving part
140: baffle 141: fixed baffle
142: variable baffle 143: baffle elevating drive part
150: control unit 151: flow sensor
160: floating sludge collection unit 161: collection tank

Claims (5)

Raw water that has passed through a coagulation tank and a flocculation tank flows in, and the treated water in which the contaminants contained in the raw water are separated by flotation by the microbubbles injected into the raw water flowing through the nozzle installed therein flotation tanks that flow into; and
and a retention tank into which the treated water flowing out from the flotation tank flows.
The floating tank is
By extending inward from the inner wall located on the side of the retention tank, a bubble bed formation guide positioned to be spaced apart from the bottom is provided, a dissolved air floating water treatment device capable of responding to flow rate fluctuations. The method according to claim 1,
The bubble bed formation guide,
The height adjustment is possible by being installed to ascend and descend from the inner wall of the flotation tank, and the front and rear lengths are provided to be variable along the direction extending to the inside, and the height and the front and rear lengths according to the flow rate of raw water flowing into the flotation tank Dissolved air floating oil water treatment device capable of responding to flow rate fluctuations. 3. The method according to claim 2,
The bubble bed formation guide,
a fixed guide installed to ascend and descend along the inner wall of the floating tank;
a guide elevating driving unit to enable height adjustment by allowing the fixed guide to elevate along the inner wall of the floating tank;
a variable guide movably installed in the fixed guide in a direction extending inward; and
and a length adjustment driving unit for adjusting the length by moving the variable guide from the fixed guide.
The guide elevating driving unit and the length adjustment driving unit,
Dissolved air floating water treatment device capable of responding to flow rate fluctuations, which is controlled by receiving a control signal from a control unit receiving a detection signal of a flow sensor that measures the flow rate of raw water flowing into the flotation tank. The method according to claim 1,
The floating tank is
Between a contact region that allows pollutants contained in the raw water to collide with each other by microbubbles injected into raw water flowing through a nozzle installed inside, and a separation region where the bubble-floc polymer generated by the collision is solid-liquid separated A baffle is provided to be located in
The baffle is
Dissolved air floating water treatment device that is installed so as to adjust the vertical length from the bottom of the floating tank, and the vertical length is adjusted according to the flow rate of raw water flowing into the floating tank, capable of responding to flow rate fluctuations. 5. The method according to claim 4,
The baffle is
a fixed baffle installed vertically on the bottom surface of the floating tank;
a variable baffle that is movably installed on the fixed baffle in a vertical direction; and
Including; and a baffle elevating driving unit for elevating the variable baffle from the fixed baffle.
The baffle elevating driving unit,
Dissolved air floating water treatment device capable of responding to flow rate fluctuations, which is controlled by receiving a control signal from a control unit receiving a detection signal of a flow sensor that measures the flow rate of raw water flowing into the flotation tank.

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