JP5583914B2 - Water treatment apparatus and water treatment method - Google Patents

Description

  The present invention relates to a water treatment apparatus and a water treatment method, and more particularly, to a water treatment apparatus and a water treatment method for purifying wastewater containing organic matter and the like with activated sludge.

Conventionally, as a water treatment method for purifying wastewater containing organic matter or the like, a method for purifying the wastewater with activated sludge in a tank is known. In such a water treatment method, organic substances contained in the wastewater are decomposed by microorganisms contained in the activated sludge. Therefore, the wastewater treatment capacity in this method depends on the concentration of activated sludge in the tank. In order to increase the concentration of activated sludge in this tank, conventionally, a sedimentation basin is provided on the downstream side of this tank. The method of returning to is taken.
However, such a water treatment method usually has a problem that a large sedimentation basin is required because the sedimentation rate of activated sludge is small.

From this point of view, a method has been proposed in which activated sludge aggregated by attaching activated sludge to a carrier (also referred to as “aggregated sludge body”) is formed, and wastewater is purified by the aggregated sludge body adhered to the carrier. Yes.
For example, the activated sludge is adhered to the adherend in a tank by using a water treatment apparatus having a plurality of rows of carriers each provided with an adherend to which the activated sludge is adhered and a support portion that supports the adherend. A water treatment method has been proposed in which the activated sludge is agglomerated to produce an agglomerated sludge body and the wastewater is purified by the agglomerated sludge body (for example, Patent Document 1).

  However, in such a water treatment method, if the activated sludge adheres to the attached body, no more agglomerated sludge body is formed, so that the activated sludge not attached to the attached body flows out from the tank. There is a problem that it ends up.

  Further, a method has been proposed in which activated sludge is agglomerated with a flocculant to increase the sedimentation rate of activated sludge to form a floating agglomerated sludge body, and the wastewater is purified by the floating agglomerated sludge body (for example, Patent Document 2).

JP 2001-029976 A JP 2006-015236 A

  However, in such a water treatment method, in a state where waste water is supplied into the tank and the water in the tank is discharged, the flocculant supplied into the tank immediately before the flocculant aggregates activated sludge. There is a problem that activated sludge cannot be agglomerated so much that it is discharged outside the tank. On the other hand, in the state where the waste water supply to the tank is stopped so that activated sludge is not discharged together with the water in the tank, There is a problem that the organic matter necessary for the sludge to be propagated is not supplied, and as a result, the aggregated sludge body cannot be obtained so much.

  Then, this invention makes it a subject to produce | generate an aggregate sludge body comparatively efficiently.

The present invention includes a plurality of rows of carriers each provided with an adhering body to which activated sludge is adhered and a support portion for supporting the adhering body, and the activated sludge is adhered to the adhering body in a tank. In a water treatment apparatus comprising a biological treatment unit in which activated sludge is agglomerated to produce an agglomerated sludge body and wastewater is purified by the agglomerated sludge body to obtain sludge-containing biologically treated water,
The support is formed in a thread shape,
The adhering body is formed in a thread shape, and the diameter of the adhering body is 2 to 5 mm,
The carrier is formed by providing a plurality of the adherends in a radial pattern on the support portion in the axial direction of the support portion,
Aeration means for aeration in the tank is provided,
The support members of one row and the support members of the other row are arranged so that the attachments of the one row can be swung by the aeration by the aeration means and collide with the support portions of at least one other row. The water treatment apparatus is characterized in that the distance L and the length r of the attached bodies in the one row are configured to satisfy 0.2r ≦ L ≦ 0.9r .

  According to such a water treatment apparatus, a flow of water is generated in the tank by aeration by the aeration means, so that the attachments in one row can be swung and collide with at least one of the support portions in the other row. Since the sludge body is easily separated from the adhering body by the impact of this collision, another activated sludge is attached to the adhering body and separated to form a further aggregated sludge body. Therefore, the concentration of the coagulated sludge body can be increased. Moreover, since many carriers can be arranged in the tank, more agglomerated sludge bodies are generated, and the concentration of the agglomerated sludge bodies can be further increased. Furthermore, by increasing the concentration of the aggregated sludge body, new activated sludge is generated by the aggregated sludge body and the wastewater supplied into the tank, and as a result, the concentration of the aggregated sludge body can be further increased.

  In the present invention, the purification treatment of wastewater by the aggregated sludge body is aeration of the aggregated sludge body having biological species (for example, bacteria, protozoa, metazoans, etc.) and the wastewater containing organic matter and the like. Mixing with the biological species to decompose the organic matter.

  In addition, the water treatment apparatus preferably includes a purified water treatment unit that includes a membrane unit that performs membrane filtration, and obtains purified treated water that is permeated by membrane filtration from the sludge-containing biologically treated water. .

  According to such a water treatment apparatus, waste water can be further purified by the purified treated water generating unit.

  Moreover, this invention exists in the water treatment method characterized by purifying wastewater using such a water treatment apparatus.

  As described above, according to the present invention, an aggregated sludge body can be generated relatively efficiently.

1 is a schematic diagram of a water treatment apparatus according to an embodiment. Schematic of the biological treatment part which concerns on one Embodiment. Schematic of the water treatment apparatus which concerns on other embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the water treatment apparatus 1 of the present embodiment has a biological treatment tank 21, and a biological organism that generates sludge-containing biologically treated water by purifying wastewater with activated sludge in the biological treatment tank 21. A processing unit 2 is provided.

  Moreover, the water treatment apparatus 1 of this embodiment has the flocculant addition means 3 which adds a flocculant in the said biological treatment tank 21, and the membrane unit 41 which performs membrane filtration as needed, and the said sludge containing organisms And a purified treated water generating unit 4 for obtaining purified treated water as permeated water from the treated water by membrane filtration.

  The water treatment apparatus 1 of the present embodiment further includes a waste water tank 5 that stores waste water, and is configured such that the waste water is transferred from the waste water tank 5 into the biological treatment tank 21.

  The wastewater is not particularly limited as long as it contains organic matter that can be biodegraded. Examples of the wastewater include domestic wastewater, food factories, chemical factories, electronic industry factories, Examples include wastewater from factories such as pulp mills.

  The flocculant addition means 3 includes a flocculant tank 31 that contains the flocculant, and a flocculant transfer path 33 that transfers the flocculant in the flocculant tank 31 into the biological treatment tank 21 via the flocculant pump 32. Prepare.

As the flocculant, a conventionally known flocculant can be used, and examples thereof include an inorganic flocculant and a polymer flocculant.
Examples of the inorganic flocculant include polyaluminum chloride, ferric chloride, aluminum sulfate (sulfuric acid band) and the like.
Examples of the polymer flocculant include a cationic flocculant, an anionic flocculant, and a nonionic flocculant. Examples of the cationic flocculant include water-soluble aniline resins, polyamidines, polythioureas, polyethyleneimines, quaternary ammonium salts, and polyvinylpyridines. Examples of the anionic flocculant include sodium alginate, sodium carboxymethylcellulose (CMC sodium salt), sodium polyacrylate, partially hydrolyzed salt of polyacrylamide, maleic acid copolymer and the like. Examples of nonionic flocculants include polyacrylamide, polyoxyethylene, and catalyzed starch.
As the flocculant, a cationic polymer polyamidine is preferably used from the viewpoint of facilitating the flocculation of the negatively charged activated sludge.

  As shown in FIG. 2, the biological treatment unit 2 includes two rows of carriers 22 for aggregating activated sludge in the biological treatment tank 21, and further, biological treatment aeration means 23 for aerating the inside of the biological treatment tank 21. Is provided.

  In the biological treatment unit 2, the activated sludge in the biological treatment tank 21 is aggregated by the flocculant added in the biological treatment tank 21 and the carrier 22 to form an aggregated sludge body. The waste water is separated from the carrier 22, and the waste water is purified by the aggregated sludge body separated from the carrier 22.

  The carrier 22 includes an attachment 22a to which the activated sludge is attached and a support portion 22b that supports the attachment 22a. The carrier 22 is configured such that the adhering body 22a is swung by a water flow generated by aeration by the biological treatment aeration means 23. Further, the carrier 22 is arranged so as to be separated from the membrane unit 41.

The support portion 22b is formed in a thread shape. The support portion 22b is provided such that the axis of the yarn is substantially perpendicular to the water surface in the biological treatment tank 21. Further, the support portion 22 b is fixed in the biological treatment tank 21.
Although the material which comprises the said support part 22b will not be specifically limited if this adherend 22a is supported, As this material, polyester, an acrylic resin, polyethylene, carbon fiber etc. are mentioned, for example. .

The adhering body 22a is formed in a thread shape.
Although the material which comprises the said adhesion body 22a will not be specifically limited if the said activated sludge adheres easily, As this material, an acrylic resin, polyester, polyethylene, carbon fiber etc. are mentioned, for example. .
The diameter of the attachment 22a is preferably 2 to 5 mm, more preferably about 3 mm. The length of the attachment 22a is preferably 75 to 150 mm, more preferably about 100 mm.

  The carrier 22 is formed by providing a plurality of the adhering bodies 22a in a radial pattern on the support portion 22b over the axial direction of the support portion 22b. Further, the carrier 22 is formed by providing the adhering body on the support portion at intervals of 5 to 10 mm.

  The adhering body 22a is joined to the support portion 22b at the axial end portion (joining end portion) of the adhering body 22a, and is opposite to the joining end portion by a water flow generated by aeration by the biological treatment aeration means 23. The side end (swinging end) is configured to swing.

The water treatment apparatus 1 of the present embodiment is configured such that the attached body 22a of one row 2a can be swung by the aeration by the biological treatment aeration means 23 and collide with the support portion 22b of the other row 2b. .
Specifically, in the water treatment apparatus 1 of the present embodiment, the distance L between the support portion 22b in one row and the support portion 22b in the other row is smaller than the length r of the attached body 22a in the one row. (L <r). The water treatment apparatus 1 of the present embodiment is preferably configured to satisfy 0.2r ≦ L ≦ 0.9r, more preferably 0.3r ≦ L ≦ 0.8r. Since the water treatment apparatus 1 according to the present embodiment is configured to satisfy 0.2r ≦ L, the attached body 22a easily swings, so that the attached body 22a in one row is in another row. The impact caused by the collision with the support portion 22b is increased. Therefore, there is an advantage that the aggregated sludge body attached to the attached body 22a is easily peeled off from the attached body 22a, and the aggregated sludge body is easily generated. Further, by being configured so as to satisfy L ≦ 0.9r, the adherends 22a in one row easily collide with the support portions 22b in the other rows (the collision frequency increases). The agglomerated sludge body adhering to the surface is easily peeled off from the adhering body 22a, and there is an advantage that the agglomerated sludge body is easily generated.

The particle diameter of the aggregated sludge is preferably 1 μm to 10 mm, more preferably 10 μm to 1 mm, and still more preferably 50 μm to 500 μm.
The water treatment apparatus 1 of the present embodiment has an advantage that the aggregated sludge body has a particle diameter of 1 μm or more, and thus the aggregated sludge body is liable to settle and the solid-liquid separation property is improved. There is also an advantage that clogging of the filtration membrane is less likely to occur due to the improvement in performance. Further, when the particle size of the aggregated sludge body is 10 mm or less, sufficient stirring and mixing can be performed by aeration of the apparatus, and further, the blockage between the filtration membranes due to the aggregated sludge body can be suppressed. There is.

  The biological treatment aeration means 23 includes an air diffuser 23a that diffuses air A from the holes as bubbles.

  The biological treatment tank 21 is partitioned by a partition plate 21c into a carrier region 21a in which the carrier 22 is disposed and a diffuser region 21b in which the diffuser 23a is disposed. An upper end side opening 21c1 and a lower end side opening 21c2 are formed on the upper end side and the lower end side of the partition plate 21c, respectively.

  In the biological treatment unit 2, a water flow is formed by bubbles diffused from the holes of the air diffuser 23a, and water in the air diffuser region 21b is transferred from the upper end side opening 21c1 to the carrier region 21a. The water is configured to be transferred from the lower end side opening 21c2 to the diffuser region 21b. Therefore, the biological treatment unit 2 is configured such that the diffuser region 21b is an upward flow region and the carrier region 21a is a downward flow region.

The water treatment apparatus 1 of the present embodiment is configured such that waste water is always transferred to the biological treatment tank 21 when aggregating activated sludge. Moreover, in the water treatment apparatus 1 of this embodiment, the transfer amount of the organic matter in the wastewater with respect to the volume of the biological treatment tank 21 (capacity of water that can be accommodated in the biological treatment tank 21) is preferably 2.0 to 4. 0.0 kg BOD / m ³ -volume / d.

  As shown in FIG. 1, the purified treated water generation unit 4 includes sludge concentrated water in which the aggregated sludge body is concentrated from the sludge-containing biologically treated water than the sludge-containing biologically treated water by gravity sedimentation of the aggregated sludge body. The gravity sedimentation tank 42 which produces | generates the supernatant water whose content rate of a coagulation sludge body is less than the said sludge containing biologically treated water is provided, The said membrane unit 41 permeates as a purification process water by carrying out membrane filtration of this supernatant water It is configured to obtain water.

  In the water treatment apparatus 1 of this embodiment, the sludge-containing biologically treated water is contained in the purified treated water generation unit 4, the permeated water as purified treated water in the purified treated water tank 6, and the sludge concentrated water is contained in the sludge concentrated water tank 7 and / or sludge. It is configured to be transferred to the biological treatment unit 2 as part of the biological treatment water.

  The type of filtration membrane that the membrane unit 41 has is not particularly limited. For example, a reverse osmosis membrane (RO membrane), an ultrafiltration membrane (UF membrane), a microfiltration membrane (MF membrane), and the like. Can be mentioned.

As the structure of the filtration membrane, a so-called hollow fiber membrane formed into a hollow fiber shape having a diameter of several mm formed of a material such as cellulose acetate, aromatic polyamide, polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, and the like Conventionally known types such as a so-called type and a type called a flat membrane which is a thin plate-like film can be employed.
Since the flat membrane has a membrane clearance of usually about 10 mm, when the structure of the filtration membrane is a flat membrane, the aggregated sludge body is used from the viewpoint of suppressing the clogging of the gap by the aggregated sludge body. The particle size of is preferably 10 mm or less.
Since the hollow fiber membrane has a gap between yarns of about 1 mm, when the structure of the filtration membrane is a hollow fiber membrane, the aggregation is performed from the viewpoint of suppressing the clogging of the gap by the aggregate sludge. The particle size of the sludge body is preferably 1 mm or less.

  The membrane unit 41 is installed as an immersion membrane below the liquid surface in the gravity settling tank 42.

  The membrane unit 41 includes membrane aeration means (not shown) that removes dirt such as agglomerated sludge adhering to the filtration membrane by aerating the filtration membrane constantly or intermittently by sending air A as bubbles. Become.

  The water treatment apparatus of the present embodiment is configured as described above, but in the water treatment method of the present embodiment, waste water is purified using the water treatment apparatus of the present embodiment.

  Since the present embodiment is configured as described above, it has the following advantages.

  That is, according to the present embodiment, activated sludge is first adsorbed on the carrier 22 when the activated sludge is agglomerated by the combined use of the aggregating agent added from the aggregating agent adding means 3 and the carrier 22, and the living organisms present in the activated sludge. Activated sludge is agglomerated by the binding of activated sludge by paste components (extracorporeal polymers) (for example, metabolites discharged from biological species) discharged from species (for example, bacteria, protozoa, metazoans, etc.). The agglomerated activated sludge is further solidified by the aggregating agent to form an agglomerated sludge body. Then, the activated sludge floating on the aggregated sludge body is adsorbed, and the aggregated sludge body is further aggregated by the paste component. The agglomerated sludge body that has been agglomerated and increased in particle size in this way is easily settled in the biological treatment tank 21 and hardly flows out of the biological treatment tank 21, and a new activity is generated by the agglomerated sludge body and waste water. Sludge is generated, and this new activated sludge is also aggregated, and the aggregated sludge body is generated relatively efficiently even in a state where the wastewater is supplied into the biological treatment tank 21 that purifies the wastewater using the activated sludge. There is an advantage that.

  In this embodiment, the support 22b is fixed in the biological treatment tank 21, so that the attachment 22a is swung by the water flow generated by the aeration by the biological treatment aeration means 23, while the support 22b is rocked. Since it does not move, the impact due to collision of the adhering bodies 22a in one row with the support portions 22b in the other row increases, and as a result, the aggregated sludge bodies adhering to the adhering bodies 22a are separated from the adhering bodies 22a. There is an advantage that the agglomerated sludge body is easily generated.

  Furthermore, this embodiment is provided with the gravity sedimentation tank 42, and the membrane unit 41 is configured to produce the purified treated water by subjecting the supernatant water to membrane filtration, whereby a coagulated sludge body is obtained. Since it can be easily settled, the supernatant water can be easily formed, and by filtering the supernatant water through a membrane unit, there is an advantage that clogging of the filtration membrane can be further suppressed. is there. Therefore, there is an advantage that the filtration membrane cleaning frequency and the amount of aeration for membrane cleaning can be reduced.

  Further, in the present embodiment, since the membrane unit 41 is installed as a submerged membrane below the liquid surface in the gravity settling tank 42, the structure of the device can be simplified and the device can be miniaturized. There is an advantage that you can.

  Further, the present embodiment has an advantage that the filter membrane is not damaged by the carrier because the carrier 22 is arranged so as to be separated from the membrane unit 41.

  In addition, although this embodiment has the said advantage by the said structure, this invention is not limited to the said structure, A design change is possible suitably.

  That is, although this embodiment is provided with the flocculant addition means 3, you may be comprised so that activated sludge may be aggregated only by the support | carrier 22 without using a flocculant.

  In addition, the present embodiment is provided with two rows of carriers. However, three or more rows of carriers may be provided. When three or more rows of carriers are provided, the attached bodies in one row are shaken by aeration by the aeration means. It is configured to be moved so that it can collide with at least one other row of support portions.

  Further, in the present embodiment, the attachment body 22a is formed in a thread shape. For example, the attachment body 22a is formed in a spherical shape and the support portion 22b is swung by aeration by the aeration means. 22a may be configured to swing.

  Further, in the present embodiment, the membrane unit 41 is configured to generate permeated water by subjecting the supernatant water to membrane filtration, and further, the permeated water is transferred to the purified treated water 6 as purified treated water. Although comprised, as shown in FIG. 3, the said membrane unit 41 is not provided, but it may be comprised so that the said supernatant water may be transferred to the purification process water tank 6 as purification process water.

  1: water treatment device, 2: biological treatment unit, 3: coagulant adding means, 4: purified water production unit, 5: wastewater tank, 6: purified water tank, 7: sludge concentration water tank, 21: biological treatment tank, 21a: carrier region, 21b: diffuser region, 21c1: upper end opening, 21c2: lower end opening, 22: carrier, 22a: adherent, 22b: support, 23: biological treatment aeration means, 31: aggregation Agent tank, 32: flocculant pump, 33: flocculant transfer path, 41: membrane unit, 42: gravity settling tank, A: air

Claims (3)

The activated sludge is agglomerated by attaching the activated sludge to the adhering body in a tank having a plurality of rows of carriers each having an adhering body to which the activated sludge is adhered and a support portion for supporting the adhering body. In a water treatment apparatus comprising a biological treatment unit that produces a flocculated sludge body and purifies wastewater with the flocculated sludge body to obtain sludge-containing biologically treated water,
The support is formed in a thread shape,
The adhering body is formed in a thread shape, and the diameter of the adhering body is 2 to 5 mm,
The carrier is formed by providing a plurality of the adherends in a radial pattern on the support portion in the axial direction of the support portion,
The tank is provided with aeration means for aeration,
The support members of one row and the support members of the other row are arranged so that the attachments of the one row can be swung by the aeration by the aeration means and collide with the support portions of at least one other row. A water treatment apparatus , wherein the distance L and the length r of the attached bodies in one row are configured to satisfy 0.2r ≦ L ≦ 0.9r .   The water treatment apparatus according to claim 1, further comprising a purified water treatment unit that includes a membrane unit that performs membrane filtration and obtains purified treated water that is permeated from the sludge-containing biologically treated water by membrane filtration.   A water treatment method, wherein waste water is purified using the water treatment device according to claim 1.

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