KR102328236B1 - Water Treating System and Method based on Dissolved Air Flotation - Google Patents

Abstract

The present invention is a DAF system for purifying contaminated water using a DAF, having an impeller having an S-shaped connection structure instead of a saturator, a pressurized circulating water pump and an air compressor installed in a pressurized flotation tank in the prior art. By using a microbubble pump to generate microbubbles with a diameter of 30 to 50㎛, and by optimizing the ratio of the diameter of the duct between the outer end and the inner end and the diameter ratio of the discharge hole between the outer end and the inner end in the microbubble supply diffuser, uniform Micro-bubbles are generated to maximize sludge flotation efficiency, and the structure and scale of the DAF system are reduced to the optimal state, thereby reducing the installation and operating costs of the DAF system and solving the difficulty of securing an installation site. It relates to a water treatment system and a water treatment method using a dissolved air flotation method having an integrated bubble pump structure.

Description

Water Treatment System and Method based on Dissolved Air Flotation

The present invention relates to a water treatment system and a water treatment method using Dissolved Air Flotation (hereinafter referred to as "DAF"), and specifically, to a water treatment system for purifying contaminated water using DAF (hereinafter, " DAF system"), using a microbubble pump equipped with an impeller with an S-shaped connection structure blade instead of a saturator, a pressurized circulating water pump, and an air compressor installed in the pressurized flotation tank in the prior art. Generates fine bubbles with a size of 30 to 50 μm, and optimizes the diameter ratio of the duct between the outer and inner ends and the diameter ratio of the discharge hole between the outer and inner ends in the microbubble supply diffuser By doing this, it is possible to generate uniform microbubbles to maximize sludge flotation efficiency, to reduce the structure and scale of the DAF system to the optimal state, thereby reducing the installation cost and operating cost of the DAF system, and to solve the difficulty of securing an installation site. It relates to "a water treatment system and a water treatment method using a dissolved air flotation method having an integrated structure of a microbubble pump".

Dissolved Air is a water treatment system installed in a sewage treatment plant to purify polluted water. Dissolved air flotation (dissolved air) removes pollutants present in the polluted water in the form of sludge by levitating and separating them by generating a large amount of small-sized bubbles (bubbles). Flotation / "DAF") is attracting attention. The prior art for water treatment technology using DAF is known through Korean Patent Registration No. 10-1133174 and the like.

In the conventional DAF system, a saturator is used to generate bubbles, and various auxiliary equipment such as an air compressor and a pressurized circulating water pump must be necessarily installed. And there is a problem that not only causes considerable difficulty and cost in maintenance, but also significant difficulty in securing an installation site.

Republic of Korea Patent Publication No. 10-1133174 (2012. 04. 06. Announcement).

The present invention was developed to overcome the above limitations of the prior art, and instead of the saturator, the pressurized circulating water pump and the air compressor, which made the overall structure complicated and large in the conventional DAF system, an S-shaped connection By using a micro-bubble pump that has an impeller of a structure to generate micro-bubbles of an optimal size, and an air diffuser that has an optimal configuration to uniformly discharge the generated micro-bubbles. By evenly generating fine bubbles of uniform size, the sludge flotation efficiency is maximized, and the structure and size of the DAF system are reduced to the optimal state, thereby reducing the installation and operating costs of the DAF system, and solving the difficulty of securing an installation site. The purpose is to provide the technology

In the present invention, in order to achieve the above object, the mixing tank 110 for mixing the raw water of the contaminated water containing contaminants and a chemical for flocculation; a coagulation tank 120 in which sludge is made by stirring of contaminated water mixed with chemicals; and a pressurizing flotation tank 130 in which treated water is made by floating and removing sludge by microbubbles; In the pressurization flotation tank 130 , a micro bubble pump 1 for generating micro bubbles, and a micro bubble supply diffuser device 2 for discharging the micro bubbles produced by the micro bubble pump 1 into the pressure flotation tank 130 ) and a water collecting device 3 for collecting and discharging treated water to the outside is provided; The microbubble pump 1 includes a motor and a microbubble generating unit 10; The microbubble generating unit 10 is composed of a circular rotating body, and the blades formed at the edge of the circumference are provided with an impeller 11 having an S-shaped connection structure, so that water and air are separated by the rotation of the impeller 11 There is provided a water treatment system using the dissolved air flotation method, characterized in that the mixing to generate fine bubbles.

In addition, in the present invention, in order to achieve the above object, there is provided a water treatment method using the water treatment system of the present invention, comprising: mixing raw water containing pollutants introduced into the mixing tank 110 and a chemical for coagulation; Agitating the contaminated water mixed with the chemical in the coagulation tank 120 to make sludge; and making treated water by removing the sludge by flotation by the microbubbles by the generation of microbubbles in the pressure flotation tank 130; In the pressurization flotation tank 130, a microbubble pump 1 for generating microbubbles, and a microbubble supply diffuser 2 for discharging the microbubbles made by the microbubble pump 1 into the pressurization flotation tank 130 and a water collecting device 3 for collecting and discharging treated water to the outside; The microbubble pump 1 includes a motor and a microbubble generating unit 10; The microbubble generating unit 10 is composed of a circular rotating body, and the blades formed at the edge of the circumference are provided with an impeller 11 having an S-shaped connection structure, so that water and air by the rotation of the impeller 11 are There is provided a water treatment method using a dissolved air flotation method, characterized in that mixing to generate fine bubbles.

The DAF system of the present invention uses a microbubble pump equipped with an impeller having an S-shaped connection structure instead of a conventional saturator, a pressurized circulating water pump, and an air compressor to generate microbubbles of an optimal size to produce sludge. As a result, it has a simple and compact structure as a whole compared to the conventional DAF system, and accordingly, it is possible to reduce the scale of the DAF system compared to the prior art based on the same contaminated water treatment capacity. Not only can the site required for installation be reduced, but also the effort and cost required for maintenance can be reduced, which has the effect of greatly improving the economic feasibility.

In particular, in the DAF system of the present invention, by using a bubble supply diffuser having an optimal configuration capable of uniformly discharging the generated microbubbles, microbubbles of uniform size are evenly generated in the pressurized flotation tank, Accordingly, the sludge flotation efficiency can be maximized, and the sludge removal in the pressurized flotation tank proceeds more effectively, thereby exhibiting the advantage of more efficiently treating the contaminated water.

In addition, in the DAF system of the present invention, in collecting the treated water from which the sludge has been removed from the pressurized flotation tank with a water collecting device having a collecting duct, the diameter of the duct decreases from the downstream end to the upstream end, and the size of the water collecting hole is By configuring the water collecting duct in an increased form, it has the advantage of being able to collect the treated water present in the pressurized flotation tank very efficiently and discharge it to the outside.

Furthermore, the DAF system of the present invention may be provided with a cover for sealing the pressurized flotation tank, and a malodor removal device for removing odors generated from the pressurized flotation tank may be further provided. It has the advantage of minimizing the potential for civil complaints and enabling more eco-friendly operation.

1 is a schematic diagram showing the configuration of a DAF system according to an embodiment of the present invention.
Figure 2 is a schematic view for showing the connection configuration of the microbubble pump, the microbubble supply diffuser and the water collecting device provided in the pressurization flotation tank in the present invention.
3 is a schematic side view of an embodiment of the microbubble generating unit provided in the microbubble pump according to the present invention.
4 is a schematic perspective view of an impeller provided in the microbubble generating unit of FIG. 3 .
FIG. 5 is a schematic perspective view of the microbubble supply diffuser of FIG. 2 .
6 is a schematic plan view of the micro-bubble supply diffuser of FIG. 5 .
7 is a schematic diagram showing the fluid flow velocity in the diffuser duct when the diameter of the duct at the outer end and the diameter of the duct at the inner end are the same in the diffuser duct.
8 is a schematic view showing the fluid flow velocity inside the duct when the ratio of the diameter of the duct at the outer end to the diameter of the duct at the inner end is 0.7 in the diffuser duct.
9 is a schematic graph showing a comparison of the microbubble discharge rate in the discharge hole for each case of FIGS. 7 and 8 .
10 is a schematic plan view of a water collecting device according to an embodiment of the present invention.
11 is a schematic side view of the water collecting device shown in FIG. 10 .
12 is a schematic diagram showing a fluid flow velocity aspect in a DAF system according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiment shown in the drawings, which is described as one embodiment, the technical idea of the present invention and its core configuration and operation are not limited thereby.

1 is a schematic diagram showing the configuration of a DAF system 100 according to an embodiment of the present invention. As shown in the drawing, the DAF system 100 of the present invention includes a mixing tank 110 , a coagulation tank 120 , and a pressure flotation tank 130 . Raw water of contaminated water containing contaminants flows into the mixing tank 110 , and mixing of the coagulation chemical with the raw water proceeds in the mixing tank 110 . The contaminated water mixed with the chemical is subsequently supplied to the coagulation tank 120 , and the coagulation tank 120 is equipped with a circulator or propeller. This produces sludge in the form of a floc. At this time, it is preferable to rotate one or a plurality of propellers or stirrers at different rotational speeds. In the drawing, the letter M denotes a motor M for rotating a propeller or agitator provided in the mixing tank 110 and the coagulation tank 120 .

As a subsequent process, in the pressurization flotation tank 130 , the sludge generated in the coagulation tank 120 is floated by generating microbubbles, and the floated sludge is a sludge collector 131 provided at the top of the pressurization flotation tank 130 . ) is collected by If necessary, the pressure flotation tank 130 may be provided with a sludge storage tank 132 for temporarily storing the collected sludge, and the sludge collected by the sludge collector 131 is stored in the sludge storage tank 132 and the sludge drain pipe discharged sequentially through

2 is a schematic diagram showing the connection configuration of the microbubble pump (1), the microbubble supply diffuser (2) and the water collecting device (3) provided in the pressurization flotation tank 130 is shown. In FIG. 2, for convenience, the microbubble supply diffuser 2 and the water collector 3 are shown in the form of a plan view viewed from above. In the present invention, in the pressurized flotation tank 130, a microbubble pump (1) for generating and homogeneously distributing microbubbles to float the sludge in the form of floc, a microbubble pump (1), a microbubble supply diffuser (2), and treated water are collected. A water collecting device 3 for discharging to the outside is provided. The microbubble pump 1 generates microbubbles of a very small size, and the microbubble supply diffuser 2 discharges the microbubbles made by the microbubble pump 1 to be uniformly distributed in the pressurization flotation tank 130 . will make it The water collecting device 3 collects the treated water in the pressurized flotation tank 130 for external discharge.

First, look at the micro bubble pump (1). The microbubble pump 1 according to the present invention generates very small micro bubbles with a diameter of 30 to 50 μm, unlike the conventional bubble pump that generates bubbles having a large diameter of 100 μm or more. To this end, the microbubble pump 1 provided in the present invention includes a motor and a microbubble generating unit 10 that generates microbubbles by mixing treated water and air, and the microbubble generating unit 10 ) has an S-shaped connection structure impeller. 3 is a schematic side view of an embodiment of the microbubble generating unit 10 provided in the microbubble pump 1 according to the present invention, and in FIG. 4 the microbubble generating unit 10 of FIG. 3 is shown. A schematic perspective view of the impeller 11 provided in the is shown.

As illustrated in the drawing, the microbubble pump 1 of the present invention is provided with a microbubble generating unit 10, and the microbubble generating unit 10 is provided with an impeller 11 rotated by a motor. As illustrated in FIG. 3 , air from the outside is supplied to the inlet 12 together with water, and fine bubbles are formed by the rotation of the impeller 11 and discharged through the outlet 13 . At this time, the water in the pressurization flotation tank 130 may be supplied to the inlet of the microbubble generating unit 10, but after the contaminants are treated, the treated water collected and discharged by the water collecting device 3 is circulated again to It is preferable to supply to the inlet of the microbubble generating unit 10 or to supply this circulating water to the inlet together with water newly supplied from the outside. In this case, the circulating water is preferably about 30-50% with respect to 100% of the total water supplied to the inlet.

In such a microbubble generating unit 10 of the present invention, the impeller 11 is made of a circular rotating body, and the blade formed at the edge of the circumference has an S-shaped connection structure. That is, the English letter 'S' is continuously connected along the edge of the circumference in the impeller 11 to form wings of a continuously curved shape. Since the microbubble generating unit 10 of the present invention is provided with the impeller 11 having the blades of the S-shaped connection structure as described above, when the impeller 11 rotates, it flows into the microbubble generating unit 10 through the inlet. The water is mixed at a high pressure of about 5 bar with the external air introduced at a negative pressure (negative pressure) between the blades, and accordingly, very small microbubbles with a diameter of 30 to 50 μm are generated and discharged through the outlet. will do The discharged microbubbles are discharged to be uniformly distributed in the pressurizing flotation tank 130 by the microbubble supply diffuser 2 as will be described later, and the sludge in the form of floc containing contaminants is pressurized by the discharged microbubbles. It floats to the surface of the floating tank 130 .

In the conventional DAF system, since bubbles are generated using a saturator, the diameter of the bubbles is very large as 100 μm or more, and accordingly, the sludge contact area of the bubbles required for the rise of the sludge is relatively reduced. There was a problem that the efficiency was lowered. However, in the present invention, the bubbles generated and discharged by the microbubble generating unit 10 as above are very small microbubbles with a diameter of 30 to 50㎛, and the area in contact with the sludge is increased as the size of the bubble is small. As a result, sufficient air flotation ability is exhibited, and thus the sludge in the pressurized flotation tank 130 can be efficiently floated above the water surface.

As shown in FIGS. 1 and 2 , the microbubbles discharged from the microbubble generating unit 10 of the microbubble pump 1 are pressurized and supplied through a pipe, and the microbubble supply air diffuser 2 pressurizes the flotation tank 130 ) is discharged so that it is uniformly distributed within the

FIG. 5 is a schematic perspective view showing only the fine bubble supply diffuser 2 in FIG. 2, and FIG. 6 is a schematic view showing the fine bubble supply diffuser 2 of FIG. 5 in a top-down view. A top plan view is shown. The fine bubble supply diffuser 2 is a member connected to the end of the conduit to which the fine bubbles are supplied, and as illustrated in the figure, the air diffuser duct ( duct) 21 has a horizontally extended configuration. A plurality of discharge holes 22 for ejecting fine bubbles upward are formed on the upper surface of the diffuser duct 21 at intervals in the extending direction of the diffuser duct 21 .

At this time, in the present invention, the diffuser duct 21 has a tapered shape in which the tube diameter (duct diameter or duct inner diameter) gradually decreases from the inner end close to the supply pipe connection part 20 to the outer end. In particular, since the diffuser duct 21 has such a tapered shape, the duct _{pipe diameter d 1} at the outer end of the diffuser duct 21 and the duct pipe diameter at the inner end where the supply pipe connection part 20 is connected ( It is preferable that the ratio of d _{2 ) is 0.5 to 0.7.} That is, when the size of the duct diameter d2 at the inner end of the diffuser duct 21 is 1, the size of the duct diameter d1 at the outer end of the diffuser duct 21 is 0.5 to 0.7. Reference numeral 21 denotes a tapered shape in which the inner diameter decreases toward the outer end.

When the fine bubbles are discharged through the discharge hole 22 of the diffuser duct 21, it is necessary that the internal pressure of the diffuser duct 21 is uniform in the longitudinal direction of the diffuser duct 21 in order to achieve a uniform discharge speed. desirable. However, according to the Bernoulli theorem, when a fluid flows inside a tubular duct, the sum of the pressure and velocity inside the duct is constant at each position in the longitudinal direction of the duct. If the velocity of the fluid inside the duct is high at a specific location in the duct, the pressure will be low, whereas if the velocity of the fluid is low, the pressure will be high. 7 is a schematic diagram showing the fluid flow rate inside the duct when both _{the duct diameter d 1} at the outer end and the duct diameter d _{2 at the inner end of the diffuser duct 21 are the same.} If the diffuser duct 21 has a uniform duct diameter (inner diameter) over the entire extended length, at the inlet side where the fluid (air) flows in, that is, at the inner end close to the supply pipe connection part 20, Because the velocity is high, the pressure is relatively low, and accordingly, the speed at which the microbubbles are discharged from the discharge hole is lowered. becomes high, making it difficult to create an even discharge rate of fine bubbles as a whole in the diffuser duct 21 .

인 경우에 덕트 내부에서의 유체 유동속도를 보여주는 개략도가 도시되어 있고, 도 9에는 위에서 살펴본 산기덕트(21)의 덕트 관경이 외측 단부와 내측 단부에서 모두 동일한 경우와, 본 발명에서 제시한 것처럼 산기덕트(21)에서 외측 단부의 덕트 관경(d₁)과 내측 단부의 덕트 관경(d₂)의 비(比)가 0.7인 경우, 배출공에서의 미세버블 배출속도를 비교한 개략적인 그래프도가 도시되어 있다. 도 7 내지 도 9에서 "입구"는 산기덕트(21)에서 공급관로 연결부(20)에 가까운 내측 단부를 의미하고, "출구"는 산기덕트(21)의 외측 단부를 의미한다. In FIG. 8 , when the ratio of the duct diameter (d ₁ ) of the outer end to the duct diameter (d ₂ ) of the inner end in the diffuser duct 21 is 0.7, that is,

A schematic diagram showing the fluid flow velocity inside the duct is shown in the case where the duct diameter of the diffuser duct 21 as seen above is the same at both the outer end and the inner end, and the diffuser as presented in the present invention. In the duct 21, when the ratio of the duct diameter (d ₁ ) of the outer end to the duct diameter (d ₂ ) of the inner end is 0.7 in the duct 21, a schematic graph comparing the microbubble discharge rate in the discharge hole is is shown. 7 to 9 , "inlet" means an inner end of the diffuser duct 21 that is close to the supply pipe connection part 20, and "outlet" refers to an outer end of the diffuser duct 21 .

In the case of the present invention, as shown in FIGS. 8 and 9 according to the theorem of Berunui reviewed above, the inner end close to the supply pipe connection part 20 and the outer end far away from it have a relatively even internal fluid velocity and internal pressure. As a result, the microbubbles are also discharged at an even discharge rate from the discharge holes formed at each position. That is, as can be seen in FIG. 9 , in the diffuser duct 21 , when the duct diameter d ₁ of the outer end and the duct diameter d ₂ of the inner end are both the same, the inner end and the outer Although there is a difference of about 4 m/s or more between the ends, as presented in the present invention _{, when the ratio of the duct diameter (d 1} ) of the outer end to the duct diameter (d ₂ ) of the inner end is 0.7, the inner end and the outer The discharge velocity of microbubbles at the end has a uniform value of about 2.4-2.8 m/s as a whole. As such, in the present invention, by making the diffuser duct 21 in a tapered shape so that the ratio _{of the duct diameter d 1} of the outer end and the duct diameter d _{2 of the inner end is 0.5 to 0.7 in the present invention, microbubbles} This will exert the effect of uniformly discharging.

Furthermore, in forming the plurality of discharge holes 22 on the upper surface of the diffuser duct 21, the diameter of the discharge holes 22 gradually increases toward the outer end. Specifically, in making the size (diameter) of the discharge hole 22 formed in the air diffuser duct 21 change as described above, the diameter of the outermost discharge hole 22a existing at the outermost side at the outer end of the diffuser duct 21 is And, it is preferable that the diameter ratio of the supply pipe connection part 20 and the innermost discharge hole 22b located closest to it be 1.3 to 1.5. That is, when the diameter of the innermost discharge hole 22b in each diffuser duct 21 is 1, the outermost discharge hole 22a has a diameter of 1.3 to 1.5 from the inner end to the outer end. 22) has a configuration in which the diameter is gradually increased.

In order to evenly distribute the microbubbles over the entire pressurized flotation tank 130, it is preferable that the diffuser duct 21 extends horizontally and long in a plan view, in this case, compared to the inner end close to the supply pipe connection part 20. The pressure at the outer end of the diffuser duct 21 is inevitably reduced. In the present invention, as described above, in the diffuser duct 21, the duct diameter ratio between the outer end and the inner end is 0.5 to 0.7, and the diameter ratio between the outermost outlet hole 22a and the innermost outlet hole 22b is 1.3 to 1.5. By doing so, it is possible to compensate for the decrease in the discharge capacity due to the pressure loss occurring at the outer end due to the elongation of the diffuser duct 21 . Therefore, the fine bubbles are evenly discharged from the whole of the elongated diffuser duct 21 . That is, in the fine bubble supply diffuser device 2 according to the present invention as described above, the diameter of the duct decreases from the inner end to the outer end, and the size of the discharge hole increases. ) can be discharged to be uniformly distributed in the pressure flotation tank 130 in an optimal state.

As such, the microbubbles generated by the microbubble pump 1 and discharged to be uniformly distributed in the pressurization flotation tank 130 by the microbubble supply air diffuser 2 remove the sludge in the form of flocs containing contaminants. It will float to the surface of the pressure flotation tank (130). At this time, for smooth coupling between the sludge supplied in the form of flocks from the coagulation tank and the microbubbles discharged by the microbubble supply air diffuser 2 , the microbubble baffle (separation membrane) 4 is placed in the pressurization flotation tank 130 . may be provided, and a slant plate 5 may be installed on the upper downstream side of the microbubble baffle 4 in the pressure flotation tank 130 . The swash plate 5 relieves the flow flow at the downstream side of the microbubble baffle 4, and accordingly, the sludge that is not properly floated due to insufficient bonding with the microbubbles can be effectively precipitated. The precipitated sludge may be discharged through the sludge outlet 138 formed to have an inclination at the bottom of the pressure flotation tank 130 .

The sludge floating to the surface of the pressurized flotation tank 130 is collected using the sludge collector 131 provided on the upper part of the pressurized flotation tank 130, and then either discharged immediately or stored in the sludge storage tank 132. The sludge is discharged sequentially through the drain pipe.

On the other hand, the treated water from which the sludge is removed is discharged by the water collecting device (3). 10 is a schematic plan view of a water collecting device 3 according to an embodiment of the present invention, and FIG. 11 is a schematic side view of the water collecting device 3 shown in FIG. As illustrated in the drawing, the water collecting device 3 of the present invention has a configuration in which a plurality of water collecting ducts 31 extending long from the water collecting pipe connection part 30 toward the upstream are connected at intervals. A plurality of water collecting holes 32 for collecting treated water, respectively, are formed on both sides of the water collecting duct 31 at intervals in the longitudinal direction of the collecting duct 31 .

The water collecting duct 31, like the diffuser duct 21 described above, has a duct diameter ( duct inner diameter) has a tapered shape that gradually decreases. In addition, when the water collecting duct 31 has such a tapered shape, the ratio _{of the duct diameter d 3 at the upstream end of the water collecting duct 31 to the duct diameter d 4} at the downstream end of the water collecting duct 31 . ) is preferably 0.5 to 0.7. In addition, the plurality of water collecting holes 32 formed on the side surface of the water collecting duct 31 also have a configuration in which their diameters gradually increase as they go toward the upstream end like the discharge holes 22 . In particular, the ratio of the diameter of the most upstream water collecting hole 32a present at the end of the water collecting duct 31 to the diameter of the most downstream water collecting hole 32b existing at the most downstream side is 1.3 to 1.5. It is preferable to do As described above, the tube diameter of the duct decreases from the downstream end to the upstream end, and the treated water existing in the pressurizing flotation tank 130 is collected very efficiently by configuring the collecting duct 31 in such a way that the size of the water collecting hole increases. Thus, it can be discharged to the outside.

Through the configuration of the water collecting duct 31 and the water collecting hole 32, the treated water can be efficiently collected and discharged. 12 is a schematic diagram showing the fluid flow velocity aspect in the overall DAF system 100 in the case of having the configuration of the diffuser duct and the water collecting duct presented in the present invention. As can be seen from FIG. 12 , in the DAF system 100 according to the present invention, raw water and treated water flow in a very desirable form due to the uniform generation of microbubbles, and thus maximized sludge flotation efficiency can be shown, and water treatment effect can be maximized.

The DAF system 100 according to the present invention may further include a cover 133 that covers the upper portion of the pressurized flotation tank 130 in order to reduce the odor generated in the pressurized flotation tank 130 . As such, by covering the upper portion of the pressurizing flotation tank 130 by the cover 133 , it is possible to suppress the spread of the odor by sealing the pressurizing flotation tank 130 as much as possible. The cover 133 is installed to be able to open and close.

On the other hand, by penetrating the cover 133 so that the end of the exhaust duct 135 is positioned in the upper space of the pressurizing flotation tank 130 and installing a odor removal device 134 at the other end of the exhaust duct, the pressurizing flotation tank 130 It may be configured to remove odors from the air inside and discharge the purified air to the outside. In this way, it is possible to minimize the possibility of complaints due to the occurrence of odors. In order to efficiently remove hydrogen sulfide, methyl mercaptan, acetaldehyde, etc., which cause a high odor from sludge, a known device using a chemical cleaning method can be used as the odor removal device 134, and depending on the installation location restrictions, etc. If necessary, a biofilter may be further provided in the odor removal device 134 to be used.

The DAF system 100 of the present invention as described above uses a microbubble pump equipped with an impeller having an S-shaped connection structure blade instead of a conventional saturator, a pressurized circulating water pump, and an air compressor. Since the sludge is floated by generating micro bubbles, it has a simple and compact structure as a whole compared to the conventional DAF system. Therefore, it is possible to reduce the size of the DAF system 100 compared to the prior art based on the same polluted water treatment capacity, thereby reducing the site required for installation as well as reducing the effort and cost for maintenance. Thus, the effect of being able to greatly improve economic efficiency is exhibited.

In particular, in the DAF system 100 of the present invention, a uniform size in the pressurized flotation tank 130 by using an air diffuser having an optimal configuration for uniformly discharging the generated microbubbles. of microbubbles are evenly generated, thereby maximizing the sludge flotation efficiency. Therefore, there is an advantage that the sludge removal in the pressurization flotation tank 130 proceeds more effectively, so that the treatment of the contaminated water can be performed more efficiently. The DAF system 100 according to the present invention can be applied to various environmental facilities such as sewage treatment plants, water treatment plants, and lake purification facilities.

1: Micro bubble pump
2: Fine bubble supply diffuser
3: catchment device
4: microbubble baffle
5: swash plate
10: micro bubble generating unit
11: Impeller
21: air duct
31: water collecting duct
100: DAF system
110: mixing tank
120: coagulation tank
130: pressure flotation tank

Claims (10)

a mixing tank for mixing the raw water of contaminated water and a chemical for flocculation; a coagulation tank in which sludge is made by stirring contaminated water mixed with chemicals; and a pressurized flotation tank in which the sludge is floated and removed by microbubbles to make treated water;
The pressurized flotation tank includes a microbubble pump for generating microbubbles, a microbubble supply diffuser for discharging the microbubbles produced by the microbubble pump into the pressurization flotation tank, and a water collecting device for collecting treated water and discharging it to the outside. has been;
The microbubble pump includes a motor and a microbubble generating unit. The microbubble generating unit is composed of a circular rotating body and the blade formed at the edge of the circumference is provided with an impeller having an S-shaped connection structure. water and air are mixed to produce microbubbles;
The microbubbles generated by the microbubble pump are microbubbles with a diameter of 30 to 50 μm;
The micro-bubble supply diffuser device includes a supply pipe connection part to which a pipe to which the fine bubbles produced by the micro-bubble pump are supplied, and diffuser ducts extending horizontally from both sides of the supply pipe connection part;
On the upper surface of each diffuser duct, a plurality of discharge holes for allowing fine bubbles to be ejected upward are formed at intervals in the extending direction of the diffuser duct. It has a tapered shape in which the diameter of the duct decreases from the inner end close to the furnace connection to the outer end, and the size of the discharge hole formed in the diffuser duct increases from the inner end close to the supply pipe connection to the outer end. The diameter ratio between the outermost discharge hole located at the outermost end and the innermost discharge hole closest to the supply pipe connection part is 1.3 to 1.5;
The water collecting device includes a water collecting pipe connecting part to which a pipe for discharging collected water is connected, a downstream end coupled to the collecting pipe connecting part, and a plurality of spaced apart arranged in a form elongated toward the upstream end. It includes a water collecting duct, and a plurality of water collecting holes for sucking treated water are formed on both sides of each water collecting duct at intervals in the extending direction of the water collecting duct, and each water collecting duct is formed from a downstream end to an upstream end. It has a tapered shape so that the diameter of the duct decreases toward the duct;
Each water collecting duct has a tapered shape such that the duct diameter ratio between the upstream end and the downstream end is 0.7, and the size of the water collecting hole formed in the water collecting duct increases from the downstream end to the upstream end, the most upstream A water treatment system using the dissolved air flotation method, characterized in that the diameter ratio between the most upstream water collecting hole located at the side end and the most downstream water collecting hole located at the most downstream end is 1.3 to 1.5.
delete delete delete delete delete According to claim 1,
In order to reduce the odor generated in the pressure flotation tank is further provided with a cover covering the upper portion of the pressure flotation tank;
Dissolved air flotation, characterized in that the end of the exhaust duct is positioned in the upper space of the pressurized flotation tank by penetrating the cover, and a odor removal device is installed at the other end of the exhaust duct to remove odors from the air in the pressurized flotation tank and discharge to the outside. Water treatment system using law.
A water treatment method for purifying contaminated water using a water treatment system including a mixing tank, a coagulation tank and a pressurized flotation tank, comprising:
mixing raw water of the contaminated water introduced into the mixing tank and a chemical for flocculation; Agitating the contaminated water mixed with the chemical in a coagulation tank to make sludge; and making treated water by removing the sludge by flotation by the microbubbles by the generation of microbubbles in the pressure flotation tank;
The pressurized flotation tank includes a microbubble pump for generating microbubbles, a microbubble supply diffuser for discharging the microbubbles produced by the microbubble pump into the pressurization flotation tank, and a water collecting device for collecting treated water and discharging it to the outside. and the microbubble pump includes a motor and a microbubble generating unit;
The microbubble generating unit is composed of a circular rotating body and the blades formed at the edge of the circumference are provided with an impeller having an S-shaped connection structure, so that water and air are mixed by the rotation of the impeller to generate microbubbles;
The generated microbubbles are microbubbles with a diameter of 30 to 50 μm;
The micro-bubble supply diffuser device includes a supply pipe connection part to which a pipe to which the fine bubbles produced by the micro-bubble pump are supplied, and diffuser ducts extending horizontally from both sides of the supply pipe connection part;
On the upper surface of each diffuser duct, a plurality of discharge holes for allowing fine bubbles to be ejected upward are formed at intervals in the extending direction of the diffuser duct. It has a tapered shape in which the diameter of the duct decreases from the inner end close to the furnace connection to the outer end, and the size of the discharge hole formed in the diffuser duct increases from the inner end close to the supply pipe connection to the outer end. The diameter ratio between the outermost discharge hole located at the outermost end and the innermost discharge hole closest to the supply pipe connection part is 1.3 to 1.5;
The water collecting device includes a water collecting pipe connecting part to which a pipe for discharging collected water is connected, a downstream end coupled to the collecting pipe connecting part, and a plurality of spaced apart arranged in a form elongated toward the upstream end. It includes a water collecting duct, and a plurality of water collecting holes for sucking treated water are formed on both sides of each water collecting duct at intervals in the extending direction of the water collecting duct, and each water collecting duct is formed from a downstream end to an upstream end. It has a tapered shape so that the diameter of the duct decreases toward the duct;
Each water collecting duct has a tapered shape such that the duct diameter ratio between the upstream end and the downstream end is 0.7, and the size of the water collecting hole formed in the water collecting duct increases from the downstream end to the upstream end, the most upstream A water treatment method using the dissolved air flotation method, characterized in that the diameter ratio between the most upstream water collecting hole located at the side end and the most downstream water collecting hole located at the most downstream end is 1.3 to 1.5. delete delete

Images