JP2010058066A - Pressure flotation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure flotation apparatus which can effectively carry out any of coagulation treatment and flotation separation treatment and obtain flotation separation treated water with good water quality. <P>SOLUTION: A coagulation treated water of pH 5-7 from a coagulation tank 10 flows in a mixing room 20 via an outlet 16 and a rising passage 27. Water is taken out from the lower part in a flotation separation room 30 via a piping 21, a gas from a flotation tank 4 is pressure dissolved in a pressurized-water production apparatus 22 to produce a pressurized water, which is supplied to a nozzle 23. A mixing room 20 is loaded with an alkali agent to be pH 7-9. The coagulation treated water and the pressurized water are fully mixed and fine bubbles generated from the pressurized water are fully adhered to a coagulated floc. A floc containing water is supplied into the flotation separation room 30 to effectively separate the floc by flotation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for pressurizing and separating SS from water containing suspended solids (SS), and in particular, the agglomerated water from the coagulation tank and the pressurized water are mixed and introduced into the floatation tank. The present invention relates to a pressure levitation device.

As a treatment apparatus for water containing SS, a pressurized levitation apparatus that mixes raw water and pressurized water and supplies the mixed water to a levitation tank and levitates SS in the raw water to the surface of the water in the tank is well known. It is also known that condensed water is used as raw water for the pressure levitation device (for example, Patent Documents 1 and 2 below).
JP 2006-218281 A JP 2008-29957 A

  Especially in the agglomeration treatment aiming to remove the COD component and chromaticity component, the agglomeration reaction is carried out under acidic conditions of about pH 5 to pH 7 where the collection rate of the COD component and chromaticity component is high, and the mixture is floated by mixing with pressurized water. If the separation is attempted, the attachment of fine bubbles and flocs under acidic conditions may cause the flocs to settle without floating and separation in the levitation tank, and the flocs may flow into the levitated water.

  When the agglomeration reaction is performed under alkaline conditions convenient for adhesion of fine bubbles and flocs, the floc separation efficiency in the levitation tank is improved. However, in the agglomeration treatment tank, the amount of COD components and chromaticity components that are not collected by the flocs increases, and as a result, the COD concentration and chromaticity in the treated water that floats and separates the agglomerated treated water increases.

  The present invention solves the above-mentioned conventional problems, can efficiently perform both the agglomeration treatment and the floating separation treatment, and can obtain the floating separation treated water with good water quality.

  The pressure levitation apparatus according to claim 1 is a pressure levitation apparatus configured to mix flocculated water and pressure water from a flocculation tank, introduce the mixed water into the levitation tank, and perform levitation separation processing. A pH adjusting means for adjusting the pH of the mixed water introduced into the floating tank is provided.

  The pressure levitation apparatus according to claim 2 is characterized in that, in claim 1, the pH adjusting means adds a pH adjusting agent to a mixing chamber for mixing the flocculated water and the pressurized water. .

  According to a third aspect of the present invention, there is provided the pressurized levitation apparatus according to the first aspect, wherein the pH adjusting means adds a pH adjusting agent to at least one of the flocculated water and the pressurized water.

  A pressurized levitation apparatus according to a fourth aspect is characterized in that, in any one of the first to third aspects, the pH adjusting agent is an alkali.

  The pressurized levitation device according to claim 5 is characterized in that, in claim 4, the pH of the coagulated treated water is 5 to 7, and the pH of the mixed water introduced into the levitation tank is 7 to 9. is there.

  In the pressurized levitation apparatus of the present invention, the pH of the mixed water introduced into the levitation tank is adjusted, so that the flocculation process is performed at a pH suitable for the flocculation process, and then suitable for the levitation separation The mixed water adjusted to a high pH can be introduced into the levitation tank and subjected to the levitation separation process. Thereby, both aggregating treatment and floating separation can be performed efficiently.

  In order to adjust the pH of the mixed water introduced into the levitation tank, a pH adjusting agent may be added to the mixing chamber for mixing the flocculated water and the pressurized water, and at least one of the flocculated water and the pressurized water before mixing. A pH adjuster may be added.

  In the present invention, the aggregation treatment is preferably carried out at pH 5-7, more preferably at pH 5-6, and the flotation separation is carried out at pH 7-9, so that both the agglomeration treatment efficiency and the flotation separation efficiency are increased.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view in the longitudinal direction of a pressure levitation separator according to an embodiment.

  The inside of the tank body 3 having a substantially rectangular shape in plan view is partitioned by the partition wall 1 and the partition wall 2, so that the aggregation tank 10, the mixing chamber 20, and the floating separation chamber 30 are formed in this order. In this embodiment, the mixing tank 20 and the floating separation chamber 30 constitute the floating tank 4. The partition wall 1 and the partition wall 2 are extended in the short side direction, that is, the width direction of the tank body 3.

  At the lower part of the partition wall 1, an outlet 16 for the agglomerated treated water is formed. The upper end of the partition wall 1 extends upward from the water surface of the tank body 3 and the aggregation tank 10.

  The partition wall 2 is erected from the bottom surface of the tank body 3, and the upper end thereof is lower than the water surface of the tank body 3.

  Each wall 1, 2 is connected to both side surfaces of the tank body 3.

  The raw water is introduced into the coagulation tank 10 through the raw water pipe 11, and the coagulant and the alkali agent can be supplied through the supply pipes 12 and 13. A pH meter (not shown) for detecting the pH of the water in the coagulation tank 10 is installed, and an alkaline agent injection pump (not shown) so that the detected value of this pH meter is within a predetermined range, preferably pH 5-7. Is activated.

  As the flocculant, various organic flocculants as well as inorganic flocculants such as PAC can be used, and two or more flocculants may be used in combination. A predetermined amount of the flocculant is added by a flocculant drug pump (not shown). The water in the agglomeration tank 10 is gently agitated by the agitator 15 and agglomerated.

  The agglomerated water flows into the mixing chamber 20 through the outlet 16 and the rising channel 17. A guide plate 18 is provided in the mixing chamber 20 so as to project from the partition wall 1 toward the partition wall 2 above the ascending flow path 17. Therefore, the agglomerated water is changed in the flow direction to a substantially horizontal direction by the guide plate 18 and flows in the mixing chamber 20 along the bottom surface of the tank body 3. A nozzle 23 for discharging pressurized water is provided in the bottom surface of the tank body 3 in the center in the width direction and relatively close to the partition wall 2. The tip of the nozzle 23 slightly protrudes from the bottom surface of the tank body 3, but is not limited to this.

  In this embodiment, water is taken out from the lower part of the floating separation chamber 30 through the pipe 21, the gas from the floating tank 4 is pressurized and dissolved in the pressurized water production apparatus 22 to form pressurized water, and this pressurized water is supplied to the nozzle 23. Supply. Here, although the water for pressurized water is taken out from the lower part in the levitation separation chamber 30, the working water or clean water from the pipe 35 described later may be taken out and used, and is not particularly limited.

  In this embodiment, the nozzle 23 is disposed in a vertically lower region of an inclined partition upper portion 2b described later. In this embodiment, only one nozzle 23 is provided in the center of the bottom surface of the tank body 3 in the width direction, but a plurality of nozzles 23 may be provided.

  In this embodiment, an alkali supply pipe 25 is provided so that an alkaline agent is poured into the mixing chamber 20. The pipe 25 is provided with a chemical injection pump (not shown). The mixing chamber 20 is provided with a pH meter (not shown), and the alkaline agent is poured so that the pH in the mixing chamber 20 is preferably 7-9.

  The agglomerated water from the agglomeration tank 10 and the pressurized water from the nozzle 23 rise mainly along the vicinity of the center in the width direction of the partition wall 2 while being mixed. The partition wall 2 is a vertical part 2a that is substantially vertical (preferably within ± 10 ° with respect to the vertical surface) except for the upper part 2b, and the upper part 2b is inclined toward the partition wall 1 side.

  The upward flow flows substantially vertically upward along the vertical portion 2 a of the partition wall 2. Next, the upward flow is guided by the inclined partition upper part 2 b to change the flow direction toward the partition wall 1, and becomes a downward flow descending along the partition wall 1 when reaching the vicinity of the partition wall 1. The downward flow that has flowed to the lower part of the partition wall 1 flows toward the partition wall 2 on the bottom surface of the tank body 3 while joining the flocculated water from the flocculation tank 10. In this way, a vertical circulation flow is formed in the mixing chamber 20. During the circulation, the agglomerated water, the pressurized water, and the alkaline agent are sufficiently mixed, and the water becomes pH 7-9 mixed water in which fine bubbles generated from the pressurized water sufficiently adhere to the agglomerated floc.

  After the bubbles are sufficiently attached to the floc and the pH is adjusted as described above, the floc-containing mixed water is supplied to the floating separation chamber 30, and the floc is efficiently floated and separated.

  The floated flock is discharged to a sludge receiving chamber 32 by a scraper 31 such as a skimmer or a scraper and taken out via a discharge pipe 33.

  The sludge that has settled in the floating separation chamber 30 is discharged through the pipe 34.

  The clean water is extracted from the midway in the vertical direction of the floating separation chamber 30 by the pipe 35 and is taken out via the water level adjusting tank 36 and the extraction pipe 37. The water level adjustment tank 36 is for adjusting the water level in the tank body 3.

  In this embodiment, since the pH in the flocculation tank 10 is 5 to 7, the flocculation process is performed efficiently, and the COD component adheres sufficiently to the floc. Further, since the pH of the mixed water introduced from the mixing chamber 20 to the floating separation chamber 30 is 7 to 9, the flocs in the floating separation chamber 30 are also efficiently separated and the flocs are sufficiently separated. Water is taken out via the pipe 35.

  In the embodiment of FIG. 1, an alkaline agent is poured into the mixing chamber 20, but the pressurized water is made alkaline as shown in FIG. Alternatively, an alkaline agent may be added to adjust the pH of the mixed water in the mixing chamber 20 to 7-9.

  In FIG. 2, an alkali agent is added to the pipe 21 for introducing the floating separation treated water to the pressurized water production apparatus 22. However, since the water pressure in the pipe 21 is lower than the nozzle 23 side, the alkali agent is used. Is preferable.

  In FIG. 3, the alkaline agent is added to the ascending flow path 17, but it may be added to the lower chamber 10c of the agglomeration tank 10A as shown in FIG.

  The agglomeration tank 10A is divided into a plurality of small chambers (in this embodiment, three chambers of an upper chamber 10a, a middle chamber 10b, and a lower chamber 10c) by a shelf-like horizontal plate material 19. The center of the plate member 19 is open, and the stirring shaft of the stirrer 15 is inserted through the opened portion. The small chambers 10a, 10b, and 10c communicate with each other through an opening in the center. The raw water is introduced into the upper chamber 10a and reaches the lower chamber 10c through the middle chamber 10b.

  By setting the pH of the small chambers 10a and 10b to 5 to 7, the aggregation treatment is performed efficiently. Aggregated treated water in the lower chamber 10 c flows out from the outlet 16 to the ascending channel 17.

  By adding an alkaline agent to the lower chamber 10c, the pH of the flocculated water is increased, and as a result, the pH of the mixed water introduced from the mixing chamber 20 into the floating separation chamber 30 becomes 7-9.

  FIG. 5 (a) is a longitudinal sectional view of a pressure levitation apparatus according to another embodiment of the present invention, and FIG. 5 (b) is a plan view of the pressure levitation apparatus (however, the scum rake is not shown).

  In this pressurized levitation device, an inner tank 52 is provided along the inner periphery of the circular tank body 51 of the levitation tank 50, and the treated water can rise between the tank body 51 and the inner tank 52. A feed well 60 is erected at the center of the tank body 51, a raw water inflow pipe 53 is connected to the lower portion of the feed well 60 in a tangential direction, and a pressurized water inflow pipe 54 is connected to the raw water inflow pipe 53. Yes.

  A chemical injection pipe 61 is connected so as to add an alkaline agent into the feed well 60. A pH sensor (not shown) is installed in the feed well 60, and an alkaline agent is passed through the pipe 61 and a chemical injection pump (not shown) so that the pH of the mixed water in the feed well 60 becomes 7-9. The feed well 60 is configured to be added. The alkaline agent may be added to at least one of the inflow pipes 53 and 54 instead of the feed well 60 (or together with the feed well 60).

  Raw water and pressurized water flow into the feed well 60 through the inflow pipes 53 and 54, and an alkaline agent is added. Then, the feed well 60 moves up. This mixed water flows between the upper end of the feed well 60 and the top member 70 and flows into the inner tank 52 to be floated and separated. The treated water goes around the lower end of the inner tank 52, rises between the inner tank 52 and the tank body 51, and is discharged from the treated water trough 55. On the other hand, the floating scum is scraped by a scum rake (skimmer) 56, dropped into a scum box 58, and discharged from a discharge port (not shown). Reference numeral 57 denotes a motor for driving the scum rake 56.

  The top member 70 installed on the upper side of the feed well 60 has a conical convex portion 71 that is convex toward the center (axial center) of the feed well 60. In this embodiment, the lower end of the convex portion 71 is inserted into the upper portion of the feed well 60.

  In addition, although the convex part 71 may be not a cone shape but a pyramid shape, in order to make the flow from an outflow part isotropic, it is preferable that it is a cone shape.

  The top member 70 may be supported on the upper end of the feed well 60 through a thin column, or may be supported by the scum rake 56.

  In this embodiment, the upper surface side of the top member 70 is a conical recess, and the recess opens upward, but the recess may be closed with a lid. . Moreover, you may fill the inside of a recess with a filler. An opening / closing type outlet for taking out the deposit from the inside of the recess may be provided at the lower part of the convex portion 71.

  The top member 70 has an outer peripheral side that overlaps with the feed well 60 in a plan view or projects outward from the top member 70. That is, the diameter of the top member 70 is equal to or larger than the diameter of the feed well 60.

  In this embodiment, a plurality of annular baffles 80 are provided coaxially so as to surround the outflow gap between the upper end of the feed well 60 and the top member 70.

  The baffle 80 is supported by the feed well 60 or the scum rake 56 through a support member.

  In this embodiment, all of the baffles 80 have an annular shape, and are arranged in a plurality of rows and upper and lower stages in a concentric manner.

  In this embodiment, the baffle 80 has a staggered arrangement.

  In the case of this staggered arrangement, the frequency of contact between the baffle 80 and the water flowing in the radial direction from the outflow gap between the feed well 60 and the top member 70 is high, and fine bubbles adhere efficiently to the floc, It is also possible to prevent the mixed water from flowing out of the tank in a short circuit, and to sufficiently perform the floating separation process.

  In the pressurized levitation device in which the raw water inflow pipe flows in the tangential direction with respect to the feed well, a drift occurs in the flow in the levitation tank due to the influence of the flow in the feed well. The annular baffle has an effect of making the flow of water from the feed well to the levitation tank uniform, and can weaken the drift. Therefore, the effect is remarkable in such a pressurized levitation device.

  The number of baffles 80 in this embodiment is an example, and the present invention is not limited to this. The number of rows of baffles 80 is preferably 2 to 10, particularly about 3 to 5. The number of baffles 80 in one row in the vertical direction is preferably about 2 to 10. The number of baffles 80 in the innermost circumferential row closest to the feed well 60 is preferably about 2 to 4, and is preferably about 0 to 8 more or less than that in the second row and thereafter.

  The baffle 80 is preferably made of a pipe having a circular cross section or a solid rod. The thickness (diameter) of the baffle 80 is preferably about 10 to 100 mm, particularly about 20 to 60 mm. The cross-sectional shape of the baffle 80 made of a pipe or a bar is not limited to a circle, and may be a rectangle, a square, a diamond, a triangle, a polygon (for example, a hexagon), an ellipse, or the like.

  In the present invention, various devices such as a vortex pump system and a compressor system can be adopted as the pressurized water production apparatus.

  In the present invention, ozone-containing pressurized water may be obtained by introducing ozone gas into the pressurized water production apparatus. In this way, even when an abnormal odor is generated from raw water or floating scum, the odor component can be decomposed and the odor can be suppressed.

It is a longitudinal cross-sectional view of the pressurization levitating apparatus which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the pressurization levitating apparatus which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view of the pressurization levitating apparatus which concerns on 3rd Embodiment. It is a longitudinal cross-sectional view of the pressurization levitating apparatus which concerns on 4th Embodiment. It is a longitudinal cross-sectional view of the pressurization levitating apparatus which concerns on 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Partition wall 2 Partition 3 Tank body 4 Floating tank 10 Agglomeration reaction chamber 15 Stirrer 16 Outlet 20 Mixing chamber 22 Pressurized water production apparatus 23 Nozzle 25 Pipe for chemical injection 30 Floating chamber 31 Scraper 50 Floating tank 51 Tank body 52 Tank 53 Raw water inflow pipe 54 Pressurized water inflow pipe 55 Treated water trough 56 Scum rake (skimmer)
58 Scum box 60 Feed well 61 Pipe for chemical injection 70 Top member 80 Baffle

Claims (5)

In a pressurized levitation apparatus configured to mix flocculated water and pressurized water from the flocculation tank, introduce the mixed water into the levitation tank, and perform levitation separation processing,
A pressure levitation apparatus comprising pH adjusting means for adjusting the pH of the mixed water introduced into the levitation tank.   2. The pressurized levitation apparatus according to claim 1, wherein the pH adjusting means is configured to add a pH adjusting agent to a mixing chamber for mixing the flocculated water and the pressurized water.   2. The pressurized levitation apparatus according to claim 1, wherein the pH adjusting means is configured to add a pH adjusting agent to at least one of the flocculated water and the pressurized water.   4. The pressurized flotation device according to claim 1, wherein the pH adjuster is an alkali.   5. The pressurized levitation apparatus according to claim 4, wherein the pH of the coagulated treated water is 5 to 7, and the pH of the mixed water introduced into the levitation tank is 7 to 9.

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