JP4937228B2 - Coagulation sedimentation equipment - Google Patents

Description

  The present invention relates to a coagulating sedimentation apparatus that settles and separates suspended substances and coagulated floc in water to be treated and forms a slurry blanket layer to clarify the water to be treated.

  When treating water to be treated that contains a lot of suspended solids in wastewater treatment or water treatment, add aluminum-based flocculants such as polyaluminum chloride and iron-based flocculants such as ferric chloride. Then, a coagulation sedimentation process is performed in which suspended substances in the water to be treated are flocked to perform sedimentation separation. In addition, when water to be treated containing an ionic substance such as fluorine is to be treated, it is reacted with a calcium agent to form calcium fluoride (solid matter), and then the flocculant is added. In addition, a coagulation sedimentation process that performs sedimentation separation is used.

  In the above coagulation sedimentation treatment method, in order to treat fluorine to a high degree, it is necessary to add a large amount of an inorganic coagulant such as an aluminum-based coagulant, but if a large amount of the coagulant is added, the sludge generated by the coagulation sedimentation treatment The dehydration property is poor, and there is a problem that the amount of cake after sludge dewatering becomes very large.

  Therefore, a method called a sludge circulation method has been adopted as a method for reducing the amount of cake after sludge dewatering. This is because part of the sludge after the coagulation sedimentation treatment is returned to the calcium reaction tank or inorganic flocculant reaction tank provided in the preceding stage, thereby increasing the sludge concentration and increasing the density, and improving the sludge cohesiveness and dewaterability. This is a method in which the moisture content is reduced (see, for example, Patent Documents 1 and 2).

  In addition, in the above sludge circulation method, in recent years, sludge regeneration treatment is performed by adding an alkali agent such as slaked lime or sodium hydroxide, or an acid agent such as sulfuric acid to the sludge to be returned in order to reduce the amount of inorganic flocculant added. Then, a method of returning to a calcium reaction tank, an inorganic flocculant reaction tank or the like is employed (see, for example, Patent Documents 3 and 4). By treating the sludge with an alkali or acid agent, the aluminum hydroxide derived from the flocculant in the sludge is dissolved, and the adsorbed fluorine is released. The released fluorine reacts with calcium in sludge, or calcium in slaked lime or calcium chloride added for pH adjustment during sludge regeneration to form calcium fluoride. The aluminum salt regenerated in this way is returned to the inorganic flocculant reaction tank and reused as the flocculant. As a result, the amount of the flocculant used can be significantly reduced, the quality of the treated water can be improved, the concentration and dewaterability of the generated sludge can be improved, and the processing equipment can be downsized.

  In the coagulation sedimentation process, a slurry blanket type sedimentation tank is often used for sedimentation separation of suspended substances in the water to be treated. The slurry blanket type sedimentation tank is an upflow type sedimentation tank, and a suspended and fluidized sludge layer called a slurry blanket layer is formed in the middle of the sedimentation tank, and the upward flow in the tank Accompanying fine flocs and other fine particles are captured by a slurry blanket layer to clarify the water to be treated. Such a slurry blanket type sedimentation tank can obtain better treated water quality than a normal upward flow type sedimentation tank that does not form a slurry blanket layer, and has a high linear velocity (LV) of 3 to 10 m / h. Have.

  For example, Patent Document 5 discloses a sludge blanket type that is connected to a chamber provided in a tank and is rotatable around a central axis of the chamber and has a distributor that discharges water to be treated from the chamber into the tank. A coagulating sedimentation device has been proposed.

  Further, for example, Patent Document 6 proposes a sludge blanket type coagulating sedimentation apparatus in which a distributor for discharging water to be treated is disposed in the vicinity of an interface position of a sludge zone formed by storing sludge at the bottom of a tank. ing.

  Further, for example, in Patent Document 7, an inflow water receiving tank is installed in a separation tank, and the upper part of the inflow water receiving tank is a first chamber and the lower part is a second chamber. The side wall is horizontally separated from the entire circumference, and a funnel-shaped flow straightening plate is installed below the inflow water receiving tank. The funnel-shaped flow straightening plate has an upper end in contact with the entire circumferential separation tank side wall, and a lower end is A coagulating sedimentation apparatus has been proposed in which the diameter is narrower than the upper end and is separated from the separation tank side wall.

Japanese Patent Publication No. 7-36911 JP 2001-9468 A JP 2005-296838 A Japanese Patent No. 2930594 Japanese Patent No. 2919462 Japanese Patent No. 3463493 Japanese Patent No. 3856314

  In the coagulation sedimentation apparatus of Patent Document 5, the water to be treated can be uniformly distributed in the tank, and clear treated water can be obtained even at a high LV. However, when the apparatus is in operation, it is stored at the bottom of the tank. It is difficult to form a slurry blanket layer early by floating the sludge immediately.

  Moreover, in the coagulation sedimentation apparatus of patent document 6, it is possible to form the slurry blanket layer at an early stage by immediately floating the sludge stored in the tank bottom during operation of the apparatus. However, when the apparatus is stopped, sludge accumulates on the distributor and the outlet of the distributor is blocked. Further, when the apparatus is in operation, the water to be treated is always sprayed onto the sludge at the bottom of the tank, the sludge is disturbed by the water to be treated, and the solid content concentration of the sludge drawn from the bottom of the tank becomes thin. In particular, when applied to a coagulation sedimentation process (for example, Patent Documents 3 and 4) involving a sludge circulation regeneration method, a sufficient coagulation effect may not be obtained at the return destination because the solid concentration of sludge is thin. In addition, in order to increase the coagulation effect, a circulation pump with a large capacity is required, which may increase the processing cost.

  Moreover, in the coagulation sedimentation apparatus of patent document 7, the sludge in a tank can be floated immediately at the time of operation of an apparatus, and a slurry blanket layer can be formed at an early stage. However, since there is only one outlet of the distributor and it is fixed, when the treatment flow rate of the treated water is large and the coagulation sedimentation tank becomes large, the uniform dispersibility of the treated water in the layer is Deteriorate. In particular, when applied to a coagulation sedimentation process (see, for example, Patent Documents 3 and 4) involving a sludge circulation regeneration method in which the flocs to be generated are heavy and the treated water SS is required to have a clear treated water quality of 10 mg / L or less. In the vicinity of the side wall, the floating of the floc is poor, and there is a case where a clear treated water quality cannot be obtained.

  Therefore, the purpose of the present invention is to improve the coagulation sedimentation treatment rate, the uniform dispersibility of the water to be treated in the tank, the early formation of a slurry blanket layer during the operation of the apparatus, the improvement of the solid matter concentration of the sludge drawn from the tank, An object of the present invention is to provide a coagulation sedimentation apparatus capable of ensuring a clear quality of treated water.

(1) The present invention is a coagulation sedimentation apparatus for clarifying the water to be treated by settling and separating suspended substances and coagulated floc in the water to form a slurry blanket layer . A partition plate that partitions the upper and lower portions, a chamber that is disposed in the upper portion of the tank and into which the water to be treated is introduced, and that is rotatably disposed at a lower end portion of the chamber. comprising a distributor for out ejection of water, wherein the distributor has a balloon tube extending toward the partition plate from the lower end of said chamber, said balloon tube, the partition plate opposed to the partition plate has blowing holes discharging the treated water towards the center of partition plates, suspended solids to settle, passage apertures floc passes are made form, the area of the passage hole, Water in the tank In the range of 10% to 60% with respect to the cross-sectional area.

(2) The present invention is a coagulation sedimentation apparatus for clarifying water to be treated by settling and separating suspended substances and coagulated floc in the water to form a slurry blanket layer . A partition plate that partitions the upper and lower portions, a chamber that is disposed in the upper portion of the tank and into which the water to be treated is introduced, and that is rotatably disposed at a lower end portion of the chamber. comprising a distributor for out ejection of water, wherein the distributor has a balloon tube extending toward the partition plate from the lower end of said chamber, said balloon tube, the partition plate opposed to the partition plate The partition plate has a plurality of passage holes through which sedimented suspended substances and aggregated flocs pass, and the total area of the passage holes is the tank. Horizontal In the range of 10% to 60% of the area.

  (3) In the coagulation sedimentation apparatus described in (1) or (2) above, it is preferable to include a scraper that scrapes sludge accumulated on the bottom of the tank.

(4) The coagulation sedimentation apparatus according to any one of (1) to (3 ) above, further comprising an interface level meter that detects an interface level of the slurry blanket layer, based on a detection value of the interface level meter. It is preferable to adjust the amount of sludge withdrawn at the bottom of the tank.

(5) In the coagulation sedimentation apparatus according to any one of (1) to (4) , the blowout hole is provided on an end surface of the blowout pipe, and the blowout pipe is configured such that the blowout hole is the partition plate. It is preferable to extend downward from the lower end portion of the chamber toward the partition plate so as to face the chamber.

  (6) The treatment apparatus for fluorine-containing water of the present invention includes a calcium reaction tank for adding calcium agent to fluorine-containing water to form calcium fluoride and generating first treated water containing calcium fluoride, An inorganic agglomeration reaction tank for adding an aluminium salt to 1 treated water to make the calcium fluoride agglomerate and flocculate to produce a second treated water containing the agglomerated flocked calcium fluoride, and suspension in the 2nd treated water Adds acid or alkali to the coagulation sedimentation device that precipitates and separates the substance and coagulated flocked calcium fluoride, forms a slurry blanket layer to clarify the water to be treated, and sludge accumulated at the bottom of the coagulation sedimentation device A regeneration treatment tank for regenerating the sludge, and a return line for returning the regenerated sludge to either the calcium reaction tank or the inorganic agglomeration reaction tank. For example, the coagulating sedimentation apparatus is a coagulation-sedimentation apparatus according to any one of the above (1) to (5).

  According to the coagulation sedimentation apparatus of the present invention, the uniform dispersibility of the water to be treated in the tank, the early formation of a slurry blanket layer during the operation of the apparatus, the improvement of the solids concentration of the sludge drawn from the tank, the clear treated water quality Securement can be achieved.

  In the present embodiment, the coagulation sedimentation apparatus according to the present embodiment will be described based on the treatment of fluorine-containing water using the sludge circulation method. The coagulation sedimentation apparatus of this embodiment is an example for carrying out the present invention, and the present invention is not limited to the treatment of fluorine-containing water using a sludge circulation method.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of a treatment apparatus for fluorine-containing water. As shown in FIG. 1, the phosphoric acid-containing water treatment apparatus 1 includes a calcium reaction tank 10, an inorganic flocculation reaction tank 12, a polymer flocculation reaction tank 14, a coagulation sedimentation apparatus 16, and a sludge regeneration tank 18.

  The calcium reaction tank 10 is connected to a fluorine-containing water supply line 20 that supplies fluorine-containing water, which is water to be treated, and a calcium agent supply line 22 that supplies calcium agent. Then, in the calcium reaction tank 10, the fluorine-containing water and the calcium agent react to form calcium fluoride. In this embodiment, the calcium reaction tank 10 is connected with a pH adjuster addition line 24 for supplying a pH adjuster such as caustic soda, and a stirring device 26 is installed in the calcium reaction tank 10. These are optional. In addition, even if it supplies to the calcium reaction tank 10 after providing the pH adjustment tank in the front | former stage of the calcium reaction tank 10, adjusting the pH of the liquid mixture of to-be-processed water and a calcium agent (for example, adjusting to pH7). Good.

  The fluorine-containing water in the present embodiment may be water of any origin as long as it contains fluorine. For example, wastewater discharged from the electronics industry including the semiconductor-related industry, the power plant, the aluminum industry, etc. However, it is not limited to these.

  The calcium agent is not particularly limited as long as it can generate calcium fluoride, and examples thereof include calcium hydroxide, calcium chloride, calcium carbonate, and the like, but are not limited thereto.

  After the formation of calcium fluoride, the first treated water containing calcium fluoride is supplied to the inorganic agglomeration reaction tank 12 via the first treated water supply line 28. An inorganic flocculant addition line 30 for supplying an inorganic flocculant such as an aluminum salt is connected to the inorganic agglomeration reaction tank 12. In the inorganic agglomeration reaction tank 12, the inorganic flocculant adsorbs the fluorine that remains without reacting with the calcium agent, and the calcium fluoride in the water to be treated is agglomerated and flocked. Moreover, although the stirring apparatus 32 is installed in the inorganic aggregation reaction tank 12, installation of this stirring apparatus 32 is arbitrary. Further, a sludge return line 34 is connected to the inorganic agglomeration reaction tank 12, and regenerated sludge described later is supplied to the inorganic agglomeration reaction tank 12 through the sludge return line 34. The sludge return line 34 may be connected to the calcium reaction tank 10 described above, and regenerated sludge may be added to the calcium reaction tank 10.

  As the inorganic flocculant such as an aluminum salt, any known flocculant can be used as long as it functions as a flocculant capable of aggregating and flocking calcium fluoride. For example, PAC, sulfate band However, it is not limited to these.

  Next, the second treated water containing coagulated flocked calcium fluoride is supplied to the polymer agglomeration reaction tank 14 via the second treated water supply line 36. A polymer flocculant addition line 38 for supplying a polymer flocculant is connected to the polymer flocculent reaction tank 14. The polymer flocculant supplied from the polymer flocculant addition line 38 is added to and mixed with the second treated water in the polymer flocculation reaction tank 14, so that the coagulability of calcium fluoride in the second treated water is increased. It can be further increased. Thereby, the fine calcium fluoride (suspended substance) that has not been aggregated in the inorganic aggregation reaction tank 12 is aggregated and flocked. Moreover, although the stirring apparatus 40 is installed in the polymer agglomeration reaction tank 14, the installation of the stirring apparatus 40 is optional.

  As the polymer flocculant, any polymer that further improves the flocculence of calcium fluoride generated by adding the inorganic flocculant in the inorganic flocculent reaction tank 12 can be used. For example, anionic polymer organic Examples thereof include, but are not limited to, a flocculant, a nonionic polymer organic flocculant, and a polymer organic flocculant having a cationic group.

  Examples of the anionic high molecular organic flocculant include alginic acid or a salt thereof, carboxymethylcellulose, a polymer of acrylic acid or a salt thereof, a copolymer of acrylic acid or a salt thereof and acrylamide, and the like. Is not to be done. Examples of nonionic high molecular organic flocculants include, but are not limited to, polymers of acrylamide. Examples of the polymer organic flocculant having a cationic group include, but are not limited to, cationic organic coagulants, cationic polymer organic flocculants, and amphoteric polymer organic flocculants. .

  The third treated water containing calcium fluoride coagulated and flocked in the polymer coagulation reaction tank 14 is supplied to the coagulating sedimentation device 16 via the third treated water supply line 42. Although the configuration and operation of the coagulation sedimentation device 16 will be described in detail later, in the tank, calcium fluoride in the third treated water is deposited on the tank bottom as sludge, and the third treated water is formed in the tank. After passing through the slurry blanket layer, it is clarified and becomes the final treated water. The final treated water is taken out from the treated water discharge line 44 connected to the coagulation sedimentation apparatus 16. In addition, a sludge extraction line 46 is connected to the bottom of the coagulation sedimentation apparatus 16, and sludge containing calcium fluoride deposited on the bottom of the tank is extracted from the sludge extraction line 46.

  The sludge extraction line 46 is connected to the sludge storage tank 50 via a pump 48, and a part of the sludge accumulated on the bottom of the tank is supplied to the sludge storage tank 50. Further, the sludge return line 34 is connected to the sludge extraction line 46, and sludge other than the sludge supplied to the sludge storage tank 50 is regenerated, and the inorganic agglomeration reaction tank 12 (or the calcium reaction tank 10) is regenerated as sludge. ). A sludge regeneration tank 18 is interposed in the sludge return line 34. The sludge regeneration tank 18 is connected to a regenerated sludge agent addition line 52 for adding an acid or alkali regenerated sludge agent. Then, the regenerated sludge agent is added from the regenerated sludge agent addition line 52 to the sludge regeneration tank 18, and the sludge and the regenerated sludge agent are mixed and regenerated. In addition, although the stirring apparatus 54 is installed in the sludge reproduction | regeneration tank 18, installation of this stirring apparatus 54 is arbitrary.

  When an acid is used for the regeneration treatment, the acid to be used is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid and the like. When using an alkali, the alkali to be used is not particularly limited, and examples thereof include sodium hydroxide and calcium hydroxide. In addition, it is preferable to use calcium hydroxide for the regeneration treatment. This is because calcium hydroxide can be used as a calcium source, and fluorine released from dissolved aluminum can be converted into calcium fluoride by calcium hydroxide.

  In this way, the treatment of fluorine-containing water is performed, and the configuration and operation of the coagulation sedimentation apparatus will be specifically described below.

  FIG. 2A is a schematic side view showing an example of the configuration of the coagulation sedimentation apparatus according to the present embodiment, and FIG. 2B is a schematic top view showing an example of the configuration of the coagulation sedimentation apparatus according to the present embodiment. FIG. As shown in FIGS. 2 (A) and 2 (B), the sedimentation tank 56 of the coagulation sedimentation apparatus 16 is cylindrical, and the bottom of the sedimentation tank 56 is shaped like a hopper that becomes lower toward the center. A pit 58 for collecting sludge is provided at the center of the bottom. A sludge extraction line 46 is connected to the pit 58. The shape of the sedimentation tank 56 is not limited to a cylindrical shape, and may be a polygonal shape or the like.

  A chamber 60 is provided in the sedimentation tank 56 of the coagulation sedimentation apparatus 16. The chamber 60 is a cylindrical body and is disposed at the center of the settling tank 56. A third treated water supply line 42 is connected to the chamber 60. The third treated water containing calcium fluoride coagulated and flocked in the polymer coagulation reaction tank 14 is supplied to the chamber 60 via the third treated water supply line 42.

  A distributor 64 fixed to a shaft 62 that passes through the chamber 60 is provided at the lower end of the chamber 60. The distributor 64 is rotated by driving the motor 66. By rotating the distributor 64, the uniform dispersibility of the water to be treated in the tank is maintained, so that the disturbance of the interface of the slurry blanket layer A is reduced, and a good quality of treated water can be obtained. The distributor 64 has a plurality of blow-out pipes 68, and a plurality of blow-out holes 70 for discharging the water to be treated in the chamber 60 downward in the settling tank 56 are formed at the bottom of each blow-out pipe 68. Has been. Since the blowing hole 70 is opened so that the water to be treated is discharged downward, it is configured not to be blocked by the sludge in the settling tank 56. The rotational speed of the distributor 64 is preferably in the range of 0.2 rpm to 2 rpm from the viewpoint of uniform dispersibility of the water to be treated in the settling tank 56. If the rotational speed of the distributor 64 is less than 0.2 rpm, the uniform dispersibility of the water to be treated may decrease. If it exceeds 2 rpm, the capacity of the motor 66 increases and the processing cost increases, or the motor 66 In some cases, an excessive load may be applied to cause damage.

  The number of the blow-out pipes 68 is preferably at least two or more, and more preferably an even number that can be arranged at symmetrical positions around the distributor 64 in order to balance rotation. Specifically, although depending on the amount of treated water, 2 to 8 is preferable in that the treated water can be discharged from the blow-out hole 70 and sludge accumulated on a partition plate to be described later can be suspended. . Further, although the diameter of the blow-out pipe 68 depends on the processing guess, if it is too thin, it is possible that the pipe may be blocked by a flock and that the pressure loss becomes large. Further, the horizontal length of the blow-out pipe 68 is not particularly limited, but when the sedimentation tank 56 has a large diameter, a plurality of blow-outs are provided so that the water to be treated is uniformly dispersed throughout the tank. Of the tubes 68, it is preferable to change the lengths of some of the blow-out tubes 68 in the horizontal direction.

  In addition, a partition plate 72 that partitions the inside of the tank into an upper part and a lower part is provided in the precipitation tank 56. The partition plate 72 is provided directly below the blowing hole 70. As a result, the water to be treated discharged from the blowing hole 70 can be struck against the partition plate 72 and an upward flow dispersed throughout the tank can be created. Therefore, the number of the blowing pipes 68 is reduced, and the diameter of the blowing pipe 68 is reduced. Can be bigger. Therefore, the blowout hole 70 is hardly blocked by sludge. In addition, with the above configuration, when the apparatus is stopped, the water to be treated discharged from the blow-out hole 70 immediately floats the sludge accumulated on the stage surface 72a of the partition plate 72, thereby forming the slurry blanket layer A at an early stage. As a result, it is possible to obtain good treated water quality immediately after restarting.

  Further, a passage hole 74 through which the aggregated floc in the water to be treated passes is formed at the center portion of the partition plate 72, that is, the position corresponding to the center portion in the tank. Aggregated floc that has passed through the passage hole 74 accumulates as sludge at the bottom of the sedimentation tank 56. In this embodiment, since the partition plate 72 is provided, it is suppressed that the to-be-processed water discharged from the blowing hole 70 is sprayed on the sludge accumulated in the tank bottom part. As a result, it becomes possible to improve the solid content concentration of the sludge deposited on the tank bottom.

  The area of the passage hole 74 is not particularly limited as long as the aggregated floc can move to the tank bottom without delay. For example, although the area of the passage hole 74 depends on the amount of treated water and the diameter of the settling tank 56, it is preferably in the range of 10 to 60% with respect to the horizontal sectional area of the settling tank 56. When the area of the passage hole 74 exceeds 60% with respect to the horizontal sectional area of the settling tank 56, the amount of sludge that accumulates on the stage surface 72a of the partition plate 72 is reduced when the apparatus is stopped. In this case, the amount of sludge to be suspended in order to form the slurry blanket layer A is reduced, and it may take a long time to obtain good treated water quality.

  The passage hole 74 shown in FIG. 2 is provided in the central portion of the partition plate 72, but is not necessarily limited thereto, and a plurality of passage holes 74 are provided on the surface of the partition plate 72. Also good. The total area of the plurality of passage holes 74 is preferably in the range of 10 to 60% with respect to the horizontal sectional area of the settling tank 56 as described above.

  Moreover, it is preferable that a scraper 76 that scrapes sludge accumulated on the bottom of the sedimentation tank 56 is provided at the bottom of the sedimentation tank 56. In particular, when the diameter of the sedimentation tank 56 is large, the sludge can be discharged at a high concentration without delay by installing the scraper 76. The scraper 76 is fixed to the shaft 62 and rotates together with the distributor 64. As the scraper 76 rotates, the sludge accumulated on the bottom of the sedimentation tank 56 is scraped to the pit 58 in the center of the tank.

  The precipitation tank 56 is provided with an interface level meter 78 that can detect the interface position (height of the interface) of the slurry blanket layer A formed in the tank. The interface level meter 78 is not particularly limited as long as the interface level of the slurry blanket layer A formed in the settling tank 56 can be detected. An ultrasonic interface level meter that measures the interface level of the slurry blanket layer A in 56 is preferable. As shown in FIG. 2A, the interface level meter 78 and the pump 48 provided in the sludge extraction line 46 are electrically connected.

  FIG. 3A is a schematic side view illustrating another example of the configuration of the coagulation sedimentation apparatus according to the present embodiment. FIG. 3B illustrates another example of the configuration of the coagulation sedimentation apparatus according to the present embodiment. FIG. Until now, as shown in FIG. 2, the distributor 64 has, as an example, one provided with a blowing pipe 68 extending in the horizontal direction and a blowing hole 70 formed along the longitudinal direction of the blowing pipe 68. Although described, it is not necessarily limited to this. For example, as shown in FIG. 3, the blowing hole 84 is provided in the end surface of the blowing pipe 82, and the blowing pipe 82 is arranged so that the blowing hole 84 and the partition plate 72 face each other (that is, the blowing hole 84 and the stage). The distributor 80 may be configured to extend downward from the lower end portion of the chamber 60 toward the partition plate 72 (stage surface 72a) so that the surface 72a faces the surface 72a. In addition, in this embodiment, although the blower tube 82 is bent, it is not restricted to this. The distributor 80 configured as shown in FIG. 3 is less likely to accumulate sludge on or in the distributor as compared with the distributor 64 configured as shown in FIG.

  Next, based on FIG. 3, operation | movement of the coagulation sedimentation apparatus which concerns on this embodiment is demonstrated. First, third treated water (treated water) containing coagulated flocked calcium fluoride is supplied from the third treated water supply line 42 into the chamber 60 of the settling tank 56. Then, the third treated water in the chamber 60 is discharged from the blowing hole 84 of the rotating distributor 80 onto the partition plate 72 (stage surface 72a) to generate an upward flow. In the upward flow of the third treated water, coarse aggregated flocs settle and separate by gravity, pass through the passage holes 74 of the partition plate 72, and accumulate on the bottom of the settling tank 56 to form sludge. In addition, a suspended and fluidized slurry blanket layer A made of calcium fluoride or the like is formed in an intermediate portion of the settling tank 56. By the slurry blanket layer A, fine suspended substances contained in the upward flow of the third treated water are captured. And the 3rd treated water which passed the slurry blanket layer A turns into the clear supernatant water B from which the suspended substance and the aggregation floc were removed. And the supernatant water of the upper part of the sedimentation tank 56 is taken out from the treated water discharge line 44. On the other hand, the sludge accumulated on the bottom of the settling tank 56 is scraped by the scraper 76 and pulled out from the sludge pulling line 46. In the present embodiment, the partition plate 72 prevents the third treated water discharged from the blowout holes 84 from being sprayed on the sludge accumulated on the bottom of the tank, and the sludge is prevented from being rolled up. It becomes possible to suppress concentration.

  When the apparatus is stopped, the suspended matter forming the slurry blanket layer A accumulates as sludge on the partition plate 72 (stage surface 72a). Therefore, when the apparatus is in operation, the third treated water discharged from the blowing hole 84 is sprayed on the sludge accumulated on the partition plate 72 (stage surface 72a), so that the slurry blanket layer A can be formed at an early stage. It becomes. Thereby, clear supernatant water (final treated water) can be obtained at an early stage.

  Further, in this embodiment, the amount of sludge withdrawn at the bottom of the settling tank 56 based on the interface level (interface height) of the slurry blanket layer A detected by the interface level meter 78 during operation of the apparatus. Is preferably adjusted. Thereby, the interface position of the slurry blanket layer A can be maintained in a certain range, and a stable treated water quality can be obtained. Specifically, when the interfacial level meter 78 detects that the interface level of the slurry blanket layer A in the settling tank 56 has reached a predetermined level, the pump 48 is operated for a certain period of time, or up to a predetermined level. The pump 48 is operated until the interface position is lowered, or the operation / stop cycle of the pump 48 is repeated until the interface position is lowered to a predetermined height. Further, instead of operating the pump 48, the opening / closing valve may be opened. That is, when the interface level meter 78 detects that the interface level of the slurry blanket layer A in the settling tank 56 has reached a predetermined height, the on-off valve is opened for a predetermined time, or the interface level is reduced to a predetermined level. The on-off valve may be opened until it drops, or the open / close cycle of the on-off valve may be repeated until the interface level drops to a predetermined height.

  Here, the height of the interfacial position of the slurry blanket layer A formed in the settling tank 56 varies depending on the properties of the substance to be removed in the water to be treated, but to obtain a good quality of treated water (SS, turbidity). Is preferably 0.7 m or more from the partition plate 72. The upper limit of the height of the interface position of the slurry blanket layer A is not particularly limited. However, if the height of the interface position of the slurry blanket layer A is made higher than necessary, the precipitation tank 56 needs to be made higher by that amount. Therefore, the height of the interface position of the slurry blanket layer A is preferably 2 m or less from the partition plate 72.

  Hereinafter, although an example and a reference example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

  FIG. 4 is a schematic diagram illustrating the configuration of the processing apparatus used in the examples and comparative examples. As shown in FIG. 4, the treatment apparatus 2 includes an inorganic agglomeration reaction tank 86 for mixing water to be treated, polyaluminum chloride (PAC), and sodium hydroxide to agglomerate and flock calcium fluoride, and an inorganic agglomeration reaction tank. 86. A polymer agglomeration reaction tank 88 that mixes treated water obtained by No. 86 and an organic polymer (anionic polyacrylamide) and grows flocs, and agglomeration precipitation that precipitates and separates the treated water obtained by the polymer agglomeration reaction tank 88. An apparatus. In the coagulation sedimentation apparatus, the coagulation sedimentation apparatus 90 of Example 1, the coagulation sedimentation apparatus 92 of Comparative Example 1, and the coagulation sedimentation apparatus 94 of Comparative Example 2 are installed in parallel at the subsequent stage of the polymer coagulation reaction tank 88 to polymer coagulation. The treated water obtained from the reaction tank 88 was distributed and supplied to each coagulation sedimentation apparatus. The coagulation sedimentation apparatus 90 of Example 1 is the same apparatus as the apparatus shown in FIG. The coagulation sedimentation device 92 of Comparative Example 1 is the same device as the device shown in FIG. 3 except that the partition plate 72 of FIG. 3 is not installed. The coagulation sedimentation apparatus 94 of Comparative Example 2 is the same apparatus as that of Comparative Example 1 except that the distributor 64 and the scraper 76 that scrapes the sludge accumulated on the bottom of the tank are integrated.

  A sludge extraction line 46 is connected to each coagulation sedimentation apparatus. The sludge extraction line 46 includes a pump 48 for extracting sludge, an ultrasonic sludge concentration meter 96 for detecting the solid concentration of the extracted sludge, and sludge. An integrated flow meter 98 for detecting the amount of withdrawn is provided. Further, the interface position of the slurry blanket layer formed in the tank was measured by an interface level meter 78, and the sludge accumulated on the tank bottom was drawn out so that the interface position was maintained at a height of 2 m from the center of the tank bottom. .

<Processing conditions>
Water to be treated: Ground water in which calcium fluoride particles are suspended at 200 mg / L (SS: 200 mg / L)
Processed water flow rate: 16.5m ³ / h (adjusted by pump)
Water flow cycle: 12-hour water flow for 12 hours-stop for 12 hours was defined as 1 cycle, and 10 cycles were performed. Even after the water flow was stopped, the scraper was kept rotating as much as possible so as not to impair the fluidity of the sludge.
Treated water flow rate to the coagulating sedimentation device: 5.5 m ^{3 /} h (LV 5.0 m / h)
PAC added to the inorganic agglomeration reactor: 300 mg / L
Inorganic agglomeration reactor pH: 7.0
Addition amount of anionic polyacrylamide to polymer aggregation reaction: 2.5 mg / L
<Test equipment>
Inorganic agglomeration reactor size: 1.5 m ³
Polymer agglomeration reactor size: 1.5 m ³
Coagulation sedimentation apparatus tank size: φ1.2 m × 4.0 m (4.5 m ³ , effective precipitation area 1.1 m ² )

  Table 1 summarizes the average values of the solid matter concentration and the amount of extraction of sludge extracted from each coagulation sedimentation apparatus when the water to be treated was passed. As can be seen from Table 1, the solid concentration of the sludge extracted from the coagulation sedimentation apparatus of Example 1 is the highest 29000 mg / L, and the solid concentration of the sludge extracted from the coagulation sedimentation apparatus of Comparative Example 1 is 25000 mg / L. The solid concentration of sludge extracted from the coagulating sedimentation apparatus of Comparative Example 2 was 17000 mg / L, which was considerably lower than that of Example 1. Along with this, the amount of sludge withdrawn was the smallest in the coagulating sedimentation apparatus of Example 1, followed by the few coagulating sedimentation apparatuses in Comparative Example 1, and the most coagulating sedimentation apparatus in Comparative Example 2.

  As in the coagulation sedimentation apparatus of Example 1, by providing a partition plate directly under the distributor, the sludge accumulated at the bottom is concentrated almost without being disturbed by the jet of water to be treated discharged from the distributor. The solids concentration of the sludge extracted from the coagulation sedimentation apparatus of Example 1 becomes high. On the other hand, in the coagulation sedimentation apparatus of Comparative Example 1, since the distributor is separated from the bottom of the tank but no partition plate is provided, the sludge accumulated on the bottom is slightly disturbed by the jet of water to be treated discharged from the distributor. receive. Therefore, the solid matter concentration of the sludge of Comparative Example 1 is lower than that of Example 1. In the coagulation sedimentation apparatus of Comparative Example 2, since the distributor is near the bottom of the tank, the sludge accumulated on the bottom is wound up by the jet of water to be treated discharged from the distributor. Therefore, in the coagulation sedimentation apparatus of Comparative Example 2, the concentration of sludge does not proceed sufficiently, and the solid matter concentration of sludge becomes the lowest value. From these things, the coagulation sedimentation apparatus of Example 1 can fully concentrate sludge more than the coagulation sedimentation apparatus of Comparative Examples 1 and 2, and can extract at a high concentration, and accordingly, the amount of extraction sludge can be reduced. Therefore, it is possible to reduce the capacity of the sludge storage tank installed in the subsequent stage.

  Table 2 summarizes the SS and turbidity average values of the supernatant water (final treated water) obtained from each coagulation sedimentation apparatus when the treated water was passed. This average value is an average value excluding the value for 1 hour after the start of water flow. The SS and turbidity of the supernatant water obtained from the coagulation sedimentation apparatus of Example 1 were comparable to those of Comparative Examples 1 and 2. That is, it can be said that the coagulation sedimentation apparatus of Example 1 was shown to have the same SS removal performance as the conventional coagulation sedimentation apparatus.

  Table 3 shows the maximum turbidity of the treated water and the time taken for the turbidity to decrease to 0.3 degrees (average value of 9 cycles) at the time of restarting after stopping for 12 hours. The highest turbidity of the treated water was 1.5 degrees at the lowest in the coagulation sedimentation apparatus of Example 1, and then 1.8 degrees of the coagulation sedimentation apparatus in Comparative Example 2. And the coagulation sedimentation apparatus of the comparative example 1 was the highest and was 3.2 degree | times. In addition, the time required for the treated water turbidity to decrease to 0.3 degrees was 4 minutes, which was the shortest for the coagulating sedimentation apparatus of Example 1, and then 5 minutes for the coagulating sedimentation apparatus of Comparative Example 2. And the coagulation sedimentation apparatus of the comparative example 1 was 12 minutes longest.

  In the coagulation sedimentation apparatus of Example 1 and Comparative Example 2, the sludge near the distributor (sludge accumulated on the partition plate in the coagulation sedimentation apparatus of Example 1, the coagulation of Comparative Example 2) is caused by the jet of water to be treated discharged from the distributor. In the sedimentation apparatus, sludge accumulated on the bottom of the tank is immediately rolled up, and a slurry blanket layer is quickly formed. Therefore, even at the time of restarting, the SS / turbidity removal performance by the slurry blanket layer is exhibited early. On the other hand, in the case of the coagulation sedimentation apparatus of Comparative Example 1, the sludge that forms the slurry blanket layer sinks in the bottom of the tank away from the distributor due to the stop for a long time. A blanket layer cannot be formed. For this reason, the turbidity is temporarily high, and the time required for the turbidity to decrease to 0.3 degrees is also increased.

  After 10 cycles of water flow, the state of blockage of the outlet holes of the distributor in each coagulation sedimentation apparatus was confirmed. As a result, in the coagulation sedimentation apparatus of Example 1 and the coagulation sedimentation apparatus of Comparative Example 1, the blowout holes were not blocked, but in the coagulation sedimentation apparatus of Comparative Example 2, the blowout holes were easily buried in sludge when the water flow was stopped. Of the 16 blowout holes, 2 blowout holes were closed.

  As described above, the coagulation sedimentation apparatus of Example 1 has the same processing performance as the conventional coagulation sedimentation apparatus such as the coagulation sedimentation apparatuses of Comparative Examples 1 and 2, while the conventional coagulation sedimentation apparatus has a problem. In other words, it was possible to solve problems such as a decrease in the solid content concentration of sludge, early securing of good treated water quality at the time of restart, blockage of the blowout holes, and the like.

  In Example 2, treatment of fluorine-containing water was performed using an apparatus similar to the treatment apparatus shown in FIG. 1 (the coagulation sedimentation apparatus is shown in FIG. 3). Moreover, in Comparative Example 3, the treatment of fluorine-containing water was performed in the same manner as in Example 2 except that the coagulating sedimentation apparatus used in Example 2 was changed to the coagulating sedimentation apparatus used in Comparative Example 2.

<Processing conditions>
Water to be treated: water in which fluoride ions are suspended at 100 mg / L (SS <1 mg / L)
Processed water flow rate: 5.5 m ³ / h
LV of the coagulation sedimentation device: 5.0 m / h
Sludge return amount: 0.5m ³ / h
Calcium chloride added to the calcium reaction tank: 1300 mg / L
PAC addition amount to the inorganic agglomeration reaction tank: 200 mg / L
Inorganic agglomeration reactor pH: 7.0
Anionic polyacrylamide added to the polymer agglomeration reactor: 2.0 mg / L
Polymer aggregation reactor pH: 7.0
Extraction of sludge accumulated at the bottom of the coagulation sedimentation apparatus: The sludge was extracted so that the height of the interface of the slurry blanket layer formed in the tank was maintained at 2 m from the bottom of the tank.
<Test equipment>
Calcium reaction tank size: 1.5m ³
Inorganic agglomeration reactor size: 1.5 m ³
Polymer agglomeration reactor size: 1.5 m ³
Coagulation sedimentation apparatus tank size: φ1.2 m × 4.0 m (4.5 m ³ , effective precipitation area 1.1 m ² )
Sludge regeneration tank: 0.3m ³
Sludge storage tank: 3m ³

  The solid matter concentration of the sludge extracted from the coagulation sedimentation apparatus of Example 2 and Comparative Example 3, the fluorine ion concentration remaining in the supernatant water (final treated water) obtained from the coagulation sedimentation apparatus of Example 2 and Comparative Example 3, and SS is summarized in Table 4. As can be seen from Table 4, the solid concentration of the sludge extracted from the coagulation sedimentation device of Example 2 is 59000 mg / L, whereas the solid concentration of the sludge extracted from the coagulation sedimentation device of Comparative Example 3 is It was 33000 mg / L. Accordingly, in Example 2, the concentration of aluminum whose coagulation ability has been regenerated by the sludge regeneration tank is inevitably higher than that of Comparative Example 3. As a result, the fluorine ion concentration of the supernatant water obtained from the coagulation sedimentation apparatus of Comparative Example 3 was 7.8 mg / L, whereas the fluorine ion concentration of the supernatant water obtained from the coagulation sedimentation apparatus of Example 2 was It was lower than Comparative Example 3 and reduced to 4.5 mg / L. In addition, SS of supernatant water was comparable in Example 2 and Comparative Example 3.

It is a schematic diagram which shows an example of a structure of the processing apparatus of fluorine-containing water. (A) is a schematic side view illustrating an example of the configuration of the coagulation sedimentation apparatus according to the present embodiment, and (B) is a schematic top view illustrating an example of the configuration of the coagulation sedimentation apparatus according to the present embodiment. (A) is a side surface schematic diagram which shows another example of the structure of the coagulation sedimentation apparatus which concerns on this embodiment, (B) is an upper surface schematic diagram which shows another example of the structure of the coagulation precipitation apparatus which concerns on this embodiment. FIG. It is a schematic diagram which shows the structure of the processing apparatus used by the Example and the comparative example.

Explanation of symbols

  1, 2 treatment apparatus, 10 calcium reaction tank, 12,86 inorganic coagulation reaction tank, 14,88 polymer coagulation reaction tank, 16, 90, 92, 94 coagulation sedimentation apparatus, 18 sludge regeneration tank, 20 fluorine-containing water supply line , 22 Calcium agent supply line, 24 pH adjuster addition line, 26, 32, 40, 54 Stirrer, 28 First treated water supply line, 30 Inorganic flocculant addition line, 34 Sludge return line, 36 Second treated water supply Line, 38 Polymer flocculant addition line, 42 3rd treated water supply line, 44 treated water discharge line, 46 sludge extraction line, 48 pump, 50 sludge storage tank, 52 recycled sludge agent addition line, 56 sedimentation tank, 58 pits, 60 chamber, 62 shaft, 64, 80 distributor, 66 motor, 68, 82 outlet pipe, 70 84 outlets, 72 partition plate, 72a stage surface, 74 passing hole, 76 scraper machine, 78 interface level meter, 96 ultrasonic sludge concentration meter, 98 integrating flowmeter.

Claims (6)

In the tank, the suspended solids in the water to be treated, the aggregated floc is settled and separated, a slurry blanket layer is formed to clarify the water to be treated,
A partition plate for partitioning the inside of the tank into an upper part and a lower part;
Disposed on an upper portion of the tank, said a chamber treatment water is introduced, it is rotatably disposed at a lower end portion of the chamber, and a distributor for out-discharge-treatment water in the chamber,
The distributor has a blow pipe extending from the lower end of the chamber toward the partition plate,
The blowing pipe has a blowing hole that faces the partition plate and discharges the water to be treated toward the partition plate.
Wherein the central portion of the partition plate is suspended solids to settle, passage apertures floc passes are made form, the area of the passage hole is in the range of 10% to 60% with respect to the horizontal cross-sectional area of the vessel coagulating sedimentation apparatus characterized by some. In the tank, the suspended solids in the water to be treated, the aggregated floc is settled and separated, a slurry blanket layer is formed to clarify the water to be treated,
A partition plate for partitioning the inside of the tank into an upper part and a lower part;
Disposed on an upper portion of the tank, said a chamber treatment water is introduced, it is rotatably disposed at a lower end portion of the chamber, and a distributor for out-discharge-treatment water in the chamber,
The distributor has a blow pipe extending from the lower end of the chamber toward the partition plate,
The blowing pipe has a blowing hole that faces the partition plate and discharges the water to be treated toward the partition plate.
The partition plate is formed with a plurality of passage holes through which the suspended suspended matter and the aggregated flocs pass, and the total area of the passage holes is in the range of 10 to 60% with respect to the horizontal sectional area of the tank. Coagulation sedimentation device characterized by.   The coagulation sedimentation apparatus according to claim 1 or 2, further comprising a scraper for scraping the sludge accumulated on the bottom of the tank. It is a coagulation sedimentation apparatus of any one of Claims 1-3, Comprising: The interface level meter which detects the interface level of the said slurry blanket layer is provided, Based on the detected value of the said interface level meter, in the said tank A coagulating sedimentation apparatus characterized by adjusting the amount of sludge withdrawn at the bottom of the slag. It is a coagulation sedimentation apparatus of any one of Claims 1-4, Comprising: The said blowing hole is provided in the end surface of the said blowing pipe, and the said blowing pipe is such that the said blowing hole opposes the said partition plate. Further, the coagulation sedimentation apparatus extends downward from the lower end of the chamber toward the partition plate. The coagulation sedimentation apparatus according to any one of claims 1 to 5, wherein a rotational speed of the distributor is in a range of 0.2 rpm to 2 rpm.

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