KR20190042248A - Dissolved air flotation device capable of increasing organic matter recovery - Google Patents

Abstract

The present invention relates to a dissolved air flotation (DAF) apparatus and, more specifically, to a DAF apparatus capable of increasing the collection amount of an organic material. For the above, the DAF apparatus includes: a coagulating unit which mixes treated water with coagulant to form and grow a floc; a separation unit in which microbubbles are introduced through a nozzle included in a lower part, and the introduced microbubbles are attached on the flock to remove the floc by making the same floated on the water surface; and a circulation water supply line which supplies air-dissolved circulation water through a nozzle included in the separation unit. The DAF apparatus includes: an anaerobic tank which is arranged at a front end of the coagulating unit and includes a stirrer inside to stir treated water; and a floc return line which returns the floc removed in the separation unit to the anaerobic tank.

Description

DISSOLVED AIR FLOTATION DEVICE CAPABLE OF INCREASING ORGANIC MATTER RECOVERY BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a dissolved air floating apparatus, and more particularly, to a dissolved air floating apparatus capable of increasing the recovery of organic matter.

Generally, in the water treatment process or seawater desalination process, the suspended substances contained in the raw water (for-treatment water) should be removed to meet the water and drinking water standards. For this purpose, a water treatment process consisting of mixing basin, coagulation basin and flotation basin is used to remove suspended particulate matter.

In the mixing tank, the chemical and raw water are rapidly mixed to coagulate the finely suspended material, and the coagulated mixture is discharged to the coagulation tank. In the coagulation tank, the flocculated material primarily aggregated by the mixing tank is grown to a size capable of floating separation in the floating tank And discharged to the floating tank disposed at the rear end.

The separation vessel floats the agglomerates grown in the flocculation tank and removes the flocculated material. The bubbles adhere to the suspended phase contained in the dispersing medium to reach the limit surface where the dispersion medium and the air are in contact with each other Float to induce solid-liquid separation.

Dissolved Air Flotation (DAF), Dispersed Air or Cavitational Air Flotation (DAF), Induced Air Flotation (IAF), and Gaseous Air Flotation Vacuum Flotation, Electro Flotation, Microbiological Auto Flotation, etc. can be implemented in various forms.

The dissolved air flotation method (DAF) is based on the principle that when air is sufficiently dissolved in high-pressure water and introduced into the bottom of the separating tank, the high-pressure water in the water is decompressed and the supernatted air is blown out into the microcapsule. That is, the ejected minute bubbles adhere to the flocs in the raw water, and the bubble-floc combination is a water treatment method in which the specific gravity is raised to the water surface in water by buoyancy to achieve solid-liquid separation.

On the other hand, in the case of the organic material adsorption process prior to the solid-liquid separation, the organic material is oxidized by 10 ~ 65% depending on the amount of air injected and time, sludge retention time (SRT) mineralizations), resulting in poor recovery.

Therefore, it is required to develop a technique for increasing the recovery amount of organic matter.

Korean Patent Publication No. 2007-0064246

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dissolved air floating apparatus capable of improving the recovery of organic matter.

These and other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment.

The above-mentioned object is achieved by a flocculating unit comprising: a flocculating unit for mixing flotage water and flocculant to form flocs; A separation unit for introducing minute bubbles through a nozzle provided at a bottom part and floating the float to the surface while adhering the minute bubbles to the flocs; And a circulating water supply line for supplying the circulating water in which the air is dissolved to the nozzle provided in the separating part, wherein the circulating water supply line is arranged in front of the flocculating part, An anaerobic tank for containing the treated water and stirring the treated water; And a flocculation line for carrying the floc removed in the separation part to the anaerobic tank.

Preferably, the agglomerating portion includes a first agglomerated agglomerator for generating high-speed turbulence in order to form a flock primarily in the treated water filled with the first turbulent-formed derivative in the inner space; And a second agglomerated agglomerate which generates a slow turbulent flow at a lower rate than that of the first agglomerated agglomerate in order to secondarily grow the flocs in the water to be treated which has been filled with the second turbulent- And the like. The first mixed flocculating portion is provided in the upper side region of the second mixed flocculating portion so that the water to be treated which passes through the first flocculating flocculating portion is supplied to the second flocculating flocculating portion by gravity.

At this time, the first turbulent-forming derivative may be a mesh-type material having a plurality of layers stacked or a plurality of fiber bundles intertwined with each other, and the second turbulent-formation derivative may be a material of a plurality of pall rings .

The second agglomerated agglomerate may have a plurality of stages separated from each other in the form of filled with a poling type material and the plurality of stages may have a packing density of a poling type material It is preferable to provide a small size.

The agglomerating unit may further include a porous separator for separating the first agglomerating agglomerator and the second agglomerating agglomerator to maintain different turbulence intensities between the first agglomerating agglomerator and the second agglomerating agglomerator.

Preferably, the separating portion includes a plurality of floatation tanks arranged in series in series in the flow direction of the water to be treated, wherein neighboring floatation tanks are partitioned by the partition walls, and the for- You can move to the floating zone.

At this time, an adjustable weir for passing the scum floating on the upper part of the partition to the neighboring floating tank may be formed, a guide wall for floating the minute bubbles upward is formed on the bottom of the floating tank, Minute bubbles may flow into the front and rear portions of the wall, respectively.

Further, the separating section may include: a primary float tank in which flocculation and flotation are simultaneously performed; And a secondary flotation tank for flushing and removing the flocs contained in the for-treatment water that has passed through the primary flotation tank.

Preferably, the circulating water supplied through the circulating water supply line may be the treated water that has passed through the anaerobic tank.

At this time, the circulating water supply line includes a pump for pressurizing the circulating water; And an inlet pipe through which atmospheric air flows into a predetermined position of the front end of the pump. The inlet pipe may include an air flow meter and a valve for adjusting the amount of air to be introduced.

In addition, the circulating water supply line may have a stabilizer for dissolving the undeclared bubbles in the circulating water at a predetermined position of the downstream end of the pump.

According to the present invention, it is possible to increase the recovery of organic matter by disposing an anaerobic tank at the front end of the flocculation unit and transporting the floc (sludge) removed from the separation unit to the anaerobic tank.

In addition, there is an effect that fl ow removal efficiency can be increased by disposing the jet nozzle so that the for-treatment water can smoothly move in the separation portion.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a schematic view of a dissolved air floating apparatus according to an embodiment of the present invention.
2 is a view schematically showing an aggregate according to an example.
FIG. 3 is a view schematically showing an aggregate according to an example. FIG.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Also, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains and, where contradictory, Will be given priority.

In order to clearly illustrate the claimed invention, parts not related to the description are omitted, and like reference numerals are used for like parts throughout the specification. And, when a section is referred to as " including " an element, it does not exclude other elements unless specifically stated to the contrary. In addition, " part " described in the specification means one unit or block performing a specific function.

In each step, the identification code (first, second, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, and each step does not explicitly list a specific order in the context May be performed differently from the above-described sequence. That is, each of the steps may be performed in the same order as described, or may be performed substantially concurrently or in the reverse order.

1 is a schematic view of a dissolved air floating apparatus 1000 according to an embodiment of the present invention. Referring to FIG. 1, a dissolved air floating apparatus 1000 according to an embodiment of the present invention includes: a flocculating unit 100 for mixing and forming flocs with the for-treatment water and a flocculant; A separation unit 200 for introducing minute bubbles through a nozzle provided at a bottom part and floating the flocs on the water surface while adhering the introduced minute bubbles to the flocs; And a circulation water supply line (300) for supplying circulation water in which air is dissolved to a nozzle provided in the separation part (200), wherein the circulation water supply line (300) is a dissolved air flotation (DAF) An anaerobic tank 400 provided with an agitator 410 therein for agitating the water to be treated; And a floc conveyance line 500 for conveying the flocs removed from the separation unit 200 to the anaerobic tank 400.

The present invention is characterized in that the anaerobic tank 400 is placed on the upstream side of the flocculation unit 100 and the floc part removed from the separation unit 200 is transported to the anaerobic tank 400 to supply the organic material to polyhydroxyalkanoate It is possible to store and retrieve it. Specifically, when the organic material is adsorbed in the aerobic process, the organic material is oxidized by about 10 to 65% depending on the amount and time of air injection and the sludge retention time (SRT), and the organic material is mineralized to decrease the recovery rate The present invention excludes the oxidation process of organic materials and effectively removes organic accumulation of polyhydroxyalkanoate (PHA) from phosphate accumulation organisms (PAOs) and glycogen accumulating organisms (GAOs) Thereby enabling the recovery of the organic matter to be increased.

In one embodiment, the flocculating portion 100 is formed by mixing the for-treatment water transferred from the anaerobic tank 400 with a flocculant to form and grow flocs. The flocculant 100 may be composed of a single flocculating bath, The inside of which may be a non-powered cohesive chamber that is filled with a turbulent-forming derivative to generate turbulence. When the non-powered cohesion tank is constructed, the energy consumption rate can be minimized.

FIG. 2 is a schematic view of a flocculating unit 100 according to an example. Referring to FIG. 2, the flocculating unit 100 includes a first turbulent flow inducing body 111 filled in an inner space thereof A first mixed flocculation unit 110 generating high-speed turbulent flow to form flocs in the treated water to be treated; And the inner space is filled with the second turbulent-forming derivative 121, so that the second mixed flocculant 110 has a lower velocity than the first mixed flocculant 110 in order to secondarily grow flocs on the water to be treated passed through the first mixed flocculant 110 And a second mixed cohesion unit 120 for generating a slow turbulent flow. With this configuration, fine particles contained in the for-treatment water can be circulated in the inside of the for-treatment water by turbulence without contact with any agitating power, and can be brought into contact with the flocculating agent and flocculated to a predetermined size.

The first mixed cohesion part 110 is provided in the upper side area of the second mixed cohesion part 120 so that the water to be treated which passes through the first cohesion cohesion part 110 is transferred to the second cohesion cohesion part 120 by gravity, As shown in FIG.

More specifically, the water to be treated, which flows in the form of a straight water stream through the inlet pipe, passes through the first turbulent flow forming body 111 filled in the first mixed flocculation unit 110, The turbulence is formed, and flocs are formed by the contact between the fine particles contained in the raw water and the flocculant due to the generated turbulence. The first turbulent-forming derivative 111 may be a multilayer of mesh-type material or a plurality of bundles of fibers intertwined with each other. Preferably, Direction so as not to coincide with each other. Since the holes between the mesh-type materials are stacked asymmetrically in the vertical direction, it is possible to generate the turbulence while passing the material to be treated through the mesh type material by gravity, and to control the turbulent flow rate generated according to the size of the holes.

The second mixed flocculating portion 120 is a space in which the flocculant contained in the raw water can be grown due to the slow turbulent flow generated when the treated water passing through the first mixed flocculating portion 110 passes through the second turbulent flow forming conductor 121 to be. The second turbulent-forming derivative 121 may be filled with a plurality of materials of a pall ring type. Preferably, the plurality of pollen-type materials are charged into a plurality of separated stages And may have a stacked shape. More preferably, as shown in FIG. 3, the plurality of stages may be formed so that the packing density of the poling type material becomes smaller as the stage moves to the downstream side.

In other words, the second mixed flocculation unit 120 can control the number of poles filled with the poling type material depending on the state of the water to be treated. It is desirable to configure the packing density to be small because the lower the filling density, the lower the turbulence rate and the flocs can be grown into larger lumps.

The agglomerate 100 may further include a first agglomerating agglomerator 110 and a second agglomerating agglomerator 120 to maintain different turbulence intensities between the first agglomerating agglomerator 110 and the second agglomerating agglomerator 120. [ And a porous separator 130 separating the porous separator 130. That is, the first mixed flocculation unit 110 generates rapid turbulence, the second mixed flocculation unit 120 generates a slow turbulent flow, flocculates fine particles contained in the for-treatment water to form and grow flocs, The velocity of the slow turbulence is not particularly limited and can be defined as the relative difference in turbulence intensity in the coagulation flocculation tank.

In one embodiment, the separator 200 is configured such that fine bubbles are introduced through a nozzle provided at the bottom, and the inflow minute bubbles adhere to the flocs, And a plurality of floating floats arranged in series in the flow direction of the water to be treated. The floating floors adjacent to each other are partitioned by the partition 230, and the for- It moves to neighboring float. In the conventional flocculating portion of the dissolved air floating device, a mechanical agitator is separately installed inside the floatator to form a circulating water stream for inducing flocculation between the flocculant and the floating material and for growing the flocculent, and the capacity is increased to secure the residence time It is common to have multiple stages. However, the structure of the flocculated portion requires a large area, which is not only economical, but also causes a high energy consumption rate and some precipitation phenomenon at the tail portion of the flocculated portion, thereby lowering the overall water treatment efficiency. Therefore, in the present invention, instead of constituting the flocculating part 100 as a single flocculating bath, the separating part 200 is constituted by a plurality of flotation baths arranged in series in series in the flow direction of the water to be treated, So that the flotation can be performed at the same time.

At this time, the scum floating on the upper end of the partition wall 230 may be separated and removed through the skimmer. Preferably, however, the scum may be removed without installing a separate skimmer as shown in FIG. It is effective to form an adjustable weir 231 for passing to a neighboring floating structure so as to be separated and removed from the last floating structure through the skimmer.

Further, a guide wall for floating the minute bubbles upward can be formed at the bottom of the floating tank, and fine bubbles can be introduced into the front and rear portions of the guide wall 240, respectively. By supplying fine bubbles to the front and rear portions of the guide wall, the flocs that are not in contact with the microfibers at the front portion of the guide wall can sufficiently contact the microfibers at the rear portion of the guide wall, .

Preferably, the separating unit 200 includes a primary floating vessel 210 in which flocculation and floatation of the flocs are simultaneously performed; And a secondary floatation tank 220 for lifting and removing the flocs included in the for-treatment water that has passed through the primary floating tank 210 again. At this time, the partition 230 partitioning each floating tank may be provided with an injection nozzle 232 in accordance with the flow direction of the water to be treated. More specifically, referring to FIG. 1, the nozzle provided at the bottom of the separator 200 can form a flow from below to above the target water. Due to this flow, the horizontal movement of the water to be treated There is a problem that the treatment efficiency is limited. In order to smoothly control the horizontal movement of the water to be treated, the partition 230 may be provided with an injection nozzle 232 at an angle to the partition 230. That is, the spray nozzle 232 is installed in the leftmost diaphragm 230 in the downward right diagonal direction in FIG. 1, and the for-treatment water rising by the minute bubbles generated at the bottom can be moved in the lower right direction. In addition, an injection nozzle 232 is provided on the rightmost partition wall 230 in a direction diagonally downward to the left diagonal, so that the for-treatment water moves to the rear end. The injection nozzle 232 provided on the partition 230 also provides an effect of supplying more fine bubbles into the separator 200 in addition to the minute bubbles supplied by the nozzles provided at the bottom.

In one embodiment, the circulating water supply line 300 supplies the circulating water in which the air is dissolved to the nozzles provided in the separating unit 200, and the fine bubbles can be supplied to the separating unit 200 through the nozzles . The circulating water supplied through the circulating water supply line 300 may be the untreated water that has passed through the anaerobic tank 400 or the untreated water that is a mixture of the for-treatment water that has passed through the anaerobic tank 400 and the flocculant. Conventionally, it has been common practice to use treated water (water produced) that has been subjected to water treatment as circulating water. In this case, while the treated water circulates in the float baths, a part of the water treatment capacity (occupying 10-20 vol% of the total water treatment capacity) As a result, this has resulted in a reduction in the capacity of the raw water capable of water treatment and lowering the water treatment efficiency. In order to solve this problem, the use of the untreated water as the circulating water has the effect of increasing the water treatment capacity. However, as the untreated water that has not passed through the flocculating section is directly introduced into the separating section 200 The formation and growth of flocs in the treated water can not be sufficiently performed and the water treatment efficiency may be lowered.

Accordingly, in the present invention, the separating unit 200 is constituted by a plurality of floats arranged continuously in series in the flow direction of the raw water, rather than one flotation tank as in the prior art, so that coagulation and floatation are simultaneously performed in the flotation tank, Even when the for-treatment water containing the for-treatment water or the flocculant is used, flocs in the for-treatment water can be sufficiently formed and grown to prevent the water treatment efficiency from deteriorating.

Also, the circulating water supply line 300 includes a pump 310 for pressurizing the circulating water; And an inflow pipe 320 through which atmospheric air flows into a predetermined position of the front end of the pump 310. That is, atmospheric air can be introduced into the front end of the pump 310, which pressurizes the circulating water, so that pressurization of the circulating water and dissolution of air in the circulating water can be performed simultaneously.

Conventionally, it has been common to pressurize the circulating water with a pump and dissolve the pressurized water in contact with compressed air in a saturator. However, such compressed air systems require additional complicated air compressor facilities for compressed air generation and increase the capacity of the plant's service air, thereby increasing CAPEX and OPEX There was a problem.

In order to solve such a problem, the present invention is characterized in that, instead of using compressed air, atmospheric air is introduced into a front end of a pump 310 for pressurizing the circulating water, so that pressurization of the circulating water and dissolution of air in the circulating water Can be performed simultaneously.

At this time, an air flow meter and a valve are separately installed in the inflow pipe 320 for introducing the atmospheric air to control the inflow amount of the atmospheric air, thereby minimizing the cavitation or abnormal fluid phenomenon that may occur in the pump 310 .

Also, conventionally, in order to dissolve compressed air in the pressurized circulating water, a large-capacity saturator having a packing material filled therein or a structure having a wider internal surface area was used. However, since the present invention dissolves air in the pump 310, it is not necessary to use a large-capacity saturating device as in the prior art.

However, the unabbreviated bubbles in the circulating water can be formed due to the short retention time and the air fluctuation in the pump 310, so that the unheated bubbles are retained for a certain period of time It is preferable that a separate stabilizer 330 is formed at the downstream end of the pump 310 in order to redissolve it in the circulating water. The stabilizer 330 is designed to completely dissolve the undissolved bubbles in the circulating water into the pressurized circulating water while being bundled and divided, and is characterized in that the equipment and the capacity are much reduced as compared with the existing saturation device.

Conventionally, when raw water is used as the circulating water, biofouling problems due to the formation of microorganisms in the filling material in the saturation device are likely to occur, and in the case of a saturated device composed of a high-volume, high- . However, since the present invention does not use compressed air and a large-capacity saturator, even when raw water is used as circulating water, it does not cause biofouling in the saturator and the saturation efficiency is not reduced.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

1000: Dissolved air floating device
100:
110: first mixed coagulating portion
111: First turbulent flow-forming derivative
120: second mixed cohesive portion
121: Second Turbulent Formation Derivative
130: separator
200:
210: primary flotation tank
220: 2nd flotation tank
230:
231: Height adjustable wear
232: injection nozzle
240: guide wall
300: Circulating water supply line
310: pump
320: inlet piping
330: Stabilizer
400: anaerobic tank
410: stirrer
500: Floc return line

Claims (17)

An agglomerated portion for mixing the for-treatment water and the flocculant to form and grow flocs; A separation unit for introducing minute bubbles through a nozzle provided at a bottom part and floating the float to the surface while adhering the minute bubbles to the flocs; And a circulation water supply line for supplying circulation water in which air is dissolved to a nozzle provided in the separation part, wherein the circulation water supply line comprises:
An anaerobic tank disposed at the front end of the flocculating section and having an agitator therein for agitating the water to be treated; And
And a flock carrying line for carrying the flocs removed from the separating section to the anaerobic tank. 2. The apparatus according to claim 1,
A first agglomerated agglomerated portion in which a first turbulent flow-forming derivative is filled in an internal space to generate high-speed turbulence in order to form a flock primarily in the for-treatment water; And
A second mixed flocculating portion for generating a slow turbulent flow at a lower rate than the first flocculating flocculating portion in order to secondarily flocculate the for-treatment water having passed through the first flocculating flocculating portion, Wherein the dissolved air flotation apparatus comprises: 3. The method of claim 2,
Wherein the first mixed flocculating portion is provided in the upper side region of the second mixed flocculating portion so that the water to be treated which passes through the first flocculating flocculating portion is supplied to the second admixing flocculating portion by gravity. 3. The method of claim 2,
Wherein the first turbulent-forming derivative is a multilayered mesh-type material. 3. The method of claim 2,
Wherein the first turbulent-forming derivative is a plurality of fiber bundles entangled with each other. 3. The method of claim 2,
Wherein the second turbulent-forming derivative is a plurality of Pall Ring type materials. The method according to claim 6,
Wherein the second agglomerated agglomerate has a plurality of stages separated from each other by a poling type material filled. 8. The method of claim 7,
And the plurality of stages are provided such that the packing density of the poling type material becomes smaller as it goes to the downstream side. The apparatus according to claim 2,
And a porous separator for separating the first mixed coagulation unit and the second coagulation coagulation unit to maintain different turbulence intensities between the first mixed coagulation unit and the second coagulation coagulation unit. The apparatus according to claim 1,
And a plurality of floating floats arranged in series in the flow direction of the water to be treated, wherein adjacent floating floats are partitioned by partition walls, and the for-treatment water moves to a neighboring floating pool along a passage formed in a lower portion of the partition wall Of the dissolved air. 11. The method of claim 10,
Characterized in that an adjustable weir is formed on the top of the bulkhead to pass floating scum to a neighboring floating tank. 11. The method of claim 10,
Wherein a guide wall is formed at the bottom of the floating tank to float the fine bubbles upward, and fine bubbles are introduced into the front and rear portions of the guide wall, respectively. 11. The apparatus according to claim 10,
A primary flotation tank in which flocculation and flocculation occur at the same time; And
And a second floatation tank for re-floating and removing the flocs contained in the for-treatment water that has passed through the primary floatation tank. The circulating water supply system according to claim 1, wherein the circulating water supplied through the circulating water supply line
Treated water passed through the anaerobic tank. The circulating water supply system according to claim 1,
A pump for pressurizing the circulating water; And
And an inflow pipe through which atmospheric air flows into a predetermined position of the front end of the pump. 16. The apparatus according to claim 15,
Characterized in that it comprises an air flow meter and a valve for regulating the amount of air entering. 16. The water treatment system according to claim 15,
And a stabilizer for dissolving undissolved bubbles in the circulating water at a predetermined position of the downstream end of the pump.

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