JP6584372B2 - Defoaming tank, ozone treatment device and sludge treatment method - Google Patents

Description

  The present invention relates to a defoaming tank, an ozone treatment apparatus, and a sludge treatment method.

  Organic sludge generated in sewage treatment facilities includes primary sludge generated during the primary treatment of sewage, excess sludge generated during the secondary treatment of sewage, and digested sludge produced by digesting these sludges. .

  In Patent Document 1, an ozone treatment tank that foams a sludge-containing liquid by blowing ozone-containing gas into the sludge-containing liquid, and bubbles generated in the ozone treatment tank are received, and the sludge adsorbed on the foam and the sludge dissolving agent are brought into contact with each other. And a phosphorus elution tank for eluting phosphorus in the sludge-containing liquid. And it is disclosed that the phosphorus elution tank is provided with a stirrer, a liquid stirring blade and a defoaming blade, and the foam is extinguished by the defoaming blade.

JP-A-2005-219043

  Foam generated by the ozone treatment of the sludge-containing liquid containing sludge is defoamed after being separated from the sludge-containing liquid. In the conventional defoaming equipment described in Patent Document 1, since it takes time to defoam, the equipment is increased in size, and the labor and utility costs required for the processing are increased. For this reason, it is required to establish a technique capable of smoothly performing defoaming.

  Then, an object of this invention in one side is to provide the defoaming tank and ozone treatment apparatus which can reduce smoothly the bubble which generate | occur | produces by the ozone treatment of sludge containing liquid. Another object of the present invention is to provide a sludge treatment method capable of smoothly reducing bubbles generated by ozone treatment of a sludge-containing liquid.

  In one aspect, the present invention provides a defoaming tank that is provided on the downstream side of a reaction tank for treating a sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product and reducing bubbles contained in the fluid. And an antifoaming tank provided with the nozzle which discharges a fluid inside the liquid layer containing a decomposition product is provided.

  The above-described defoaming tank includes a nozzle that discharges a foam-like fluid containing a sludge decomposition product into a liquid layer containing the sludge decomposition product contained in the fluid. Thus, since the foam-like fluid is discharged to the inside of the liquid layer, bubbles contained in the fluid can be smoothly reduced as compared with the case of discharging into the foam layer or gas. The reason why such an effect can be obtained is presumed to be that bubbles can be promoted to break by colliding with the liquid layer. As a result, the defoaming tank can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  The nozzle is preferably provided on the upstream side of the nozzle and connected to a pipe body thicker than the nozzle. Thereby, the speed of the fluid flowing through the nozzle can be made larger than the speed of the fluid flowing through the tubular body. Accordingly, the fluid is ejected vigorously into the liquid layer, and the bubbles collide with the liquid layer and the bubbles are easily broken. Therefore, the reduction of bubbles can be further promoted.

  A plurality of the nozzles may be connected to the tube. In this case, it is preferable that the plurality of nozzles extend radially from the tube body and discharge fluid from the tip of the nozzle. Thereby, the contact frequency of the bubble contained in the fluid discharged from a nozzle and a liquid layer can be enlarged.

  It is preferable that the nozzle has a throttle portion that narrows the fluid flow path on the downstream side of the upstream side. When the nozzle has the throttle portion, the flow rate of the fluid discharged from the nozzle toward the inside of the liquid layer can be sufficiently increased. As a result, the bubbles collide with the liquid layer and the bubbles are easily broken. Therefore, the reduction of bubbles can be further promoted.

  It is preferable that the reaction tank includes a gas supply unit that supplies a gas containing ozone, and the nozzle discharges a fluid so that a discharge speed of the gas becomes 2 m / second or more. As a result, the foam-like fluid is ejected vigorously into the liquid layer, and the bubbles collide with the liquid layer and the bubbles are easily broken. Therefore, the reduction of bubbles can be further promoted.

  It is preferable that the defoaming tank has a communication portion that communicates with the atmosphere. The internal pressure of the defoaming tank is preferably not more than atmospheric pressure. With such a defoaming tank, the disappearance of bubbles in the defoaming tank can be promoted.

  In another aspect, the present invention provides a reaction tank for treating a sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and reducing bubbles contained in the fluid provided downstream of the reaction tank. The defoaming tank comprises an nozzle for discharging fluid into the liquid layer containing the decomposition product.

  The above-described ozone treatment apparatus includes a defoaming tank including a nozzle that discharges a foam-like fluid containing sludge decomposition products into a liquid layer containing a liquid contained in the fluid. Since the nozzle of this defoaming tank discharges the foam-like fluid into the liquid layer, the bubbles contained in the fluid can be reduced smoothly compared to the case of discharging into the foam layer or gas. it can. The reason why such an effect can be obtained is presumed to be that the foam breaks when the foam collides with the liquid layer. As a result, the defoaming tank can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  In yet another aspect, the present invention provides a reaction step in which a sludge-containing liquid is treated with ozone in a reaction tank to obtain a foam-like fluid containing a sludge decomposition product, and a quencher provided downstream of the reaction tank. The foam tank has a defoaming step for reducing foam contained in the fluid, and in the defoaming process, the foam is provided in the defoaming tank inside the liquid layer containing the decomposition product in the defoaming tank. Provided is a sludge treatment method for discharging a fluid using a nozzle.

  In the sludge treatment method described above, the foam-like fluid obtained in the reaction process is discharged into the liquid layer in the defoaming tank using a nozzle in the defoaming process. By discharging into the liquid layer in this way, bubbles contained in the fluid can be smoothly reduced as compared with the case of discharging into the bubble layer or gas. The reason why such an effect can be obtained is presumed to be that the foam breaks when the foam collides with the liquid layer. As a result, the defoaming tank can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  In the defoaming step, the nozzle preferably discharges the fluid so that the discharge speed of the gas containing ozone supplied in the reaction step is 2 m / second or more. As a result, the foam-like fluid is ejected vigorously into the liquid layer, and the bubbles collide with the liquid layer and the bubbles are easily broken. Therefore, the reduction of bubbles can be further promoted.

  According to the present invention, in one aspect, it is possible to provide an antifoaming tank and an ozone treatment apparatus that can smoothly reduce bubbles generated by ozone treatment of a sludge-containing liquid. In another aspect, it is possible to provide a sludge treatment method capable of smoothly reducing bubbles generated by ozone treatment of a sludge-containing liquid.

Drawing 1 is a figure showing one embodiment of an ozone treatment device and a defoaming tank. FIG. 2A and FIG. 2B are schematic views showing an enlarged cross section of the foam contained in the foam layer. FIG. 3 is a view showing a modification of the defoaming tank. FIG. 4 is a view of the nozzle provided in the defoaming tank of FIG. 3 when viewed from above. FIG. 5 is a view of the nozzle provided in the defoaming tank of FIG. 3 when viewed from below. FIG. 6 is a diagram illustrating a tip portion of a nozzle provided in another modification of the defoaming tank. FIG. 7 is a diagram illustrating an example of a sludge treatment system to which an ozone treatment apparatus is applied.

  In the following, embodiments of the present invention will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. In each drawing, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted in some cases.

  FIG. 1 is a diagram showing an embodiment of an ozone treatment device and an antifoaming tank provided in the ozone treatment device. The ozone treatment apparatus 100 includes a reaction tank 10 and a defoaming tank 30 provided on the downstream side of the reaction tank 10 and a pipe 16 that connects the reaction tank 10 and the defoaming tank 30. The reaction tank 10 includes a liquid supply unit 12 that supplies a sludge-containing liquid containing sludge and water to the reaction tank 10 and a gas supply unit 50 that supplies a gas containing ozone. A liquid layer 40 made of drain containing water is formed in the lower part of the reaction vessel 10. A foam layer 20 including a plurality of bubbles 21 is formed on the upper part of the reaction vessel 10. The ozone treatment apparatus 100, the defoaming tank 30, and the sludge treatment method using these will be described below.

  The gas supply unit 50 supplies a gas containing ozone into the liquid layer 40 of the reaction vessel 10. The gas supply unit 50 includes an ozone generation unit 56, an air supply unit 58, a mixing unit 55, a piping unit 54, and a diffused gas 52. As the ozone generator 56, a normal ozonizer or the like can be used. As the air supply unit 58, a normal air pump or the like can be used. The provision of the air supply unit 58 is not essential, and the air supply unit 58 may not be provided, or a supply unit that supplies an inert gas such as nitrogen may be provided instead of the air supply unit 58. .

  In the mixing unit 55, the gas 51 supplied into the liquid layer 40 is prepared by blending the ozone-containing gas generated in the ozone generation unit 56 and the air supplied from the air supply unit 58. By having such a mixing part 55, the gas discharge rate of the reaction tank 10 and the ozone supply amount (ozone unit) to the reaction tank 10 can be adjusted individually. Therefore, even if the supply amount of the sludge-containing liquid or the properties of the sludge-containing liquid changes, the sludge decomposition rate and the separation accuracy between the sludge and its decomposition products and water can be maintained at a sufficiently high level. .

The gas 51 containing ozone prepared by the mixing unit 55 flows through the piping unit 54 and is supplied to the diffused gas 52 attached to the tip of the piping unit 54. The diffused gas 52 is made of a porous material such as ceramic. The decomposition product produced by decomposing sludge with ozone has viscosity. For this reason, bubbles 21 are formed on the liquid layer 40 by supplying the gas 51 from the gas supply unit 50. By supplying the gas 51 containing ozone from the diffused gas 52, the fine bubble-like gas 51 is supplied to the liquid layer 40. As a result, the contact area between the gas and the drain containing water in the liquid layer 40 can be increased. The concentration of ozone in the gas 51 supplied from the gas supply unit 50 may be, for example, 20 to 150 mg-O ₃ / L or 50 to 120 mg-O ₃ / L.

  By supplying the gas 51 containing ozone to the liquid layer 40, ozone and the sludge contained in the liquid layer 40 can be made to react efficiently. If the gas bubbles supplied from the gas supply unit 50 are made fine, the bubbles 21 in the bubble layer 20 can also be reduced. Thereby, the entire surface area of the bubbles 21 is increased, and the contact efficiency between the sludge-containing liquid and ozone can be further increased.

  The sludge-containing liquid is, for example, sludge water generated at a sewage treatment plant, and contains water and sludge. The contents of water and sludge in the sludge-containing liquid are, for example, 30 to 80% by weight and 20 to 70% by weight, respectively. The sludge includes, for example, suspended substances (SS) and liquid organic substances (evaporation residue: TDS). The suspended substance (SS) contains an inorganic substance and a volatile organic substance (VSS component).

  The concentration of suspended matter (SS) can be measured according to “14.1 Suspended matter” of JIS K0102: 2013. Specifically, the sludge-containing liquid is filtered through a 1 μm mesh filter, and the residue is dried at 105 to 110 ° C. for measurement. The concentration of the evaporation residue (TDS) can be measured according to “14.2 Total evaporation residue” of JIS K0102: 2013. Volatile organic matter (VSS) is what disappears when the suspended matter (SS) is heated at 600 ° C. ± 25 ° C. for 0.5 hours (disappearance). The concentration of the volatile organic substance (VSS) is determined using JIS K0102: 2013 "14. Suspended substances and evaporation residues" and "14.1 Suspended substances" using the sample obtained by heating under the above heating conditions. "Can be measured in accordance with.

  In the reaction tank 10, the volatile organic matter (VSS) contained in the sludge-containing liquid reacts with ozone to produce an evaporation residue (TDS) that is a sludge decomposition product. That is, when the volatile organic substance (VSS) reacts with ozone, the cell wall of the cell which is the volatile organic substance (VSS) is decomposed, and an evaporation residue (TDS) is generated. Through such a reaction, sludge can be reduced in the reaction tank 10 by reducing suspended solids (SS).

  A pipe 18 for discharging drain is connected to the bottom of the reaction tank 10. The drain containing water contained in the sludge-containing liquid is discharged from the reaction tank 10 through the pipe 18. In the reaction tank 10, since the sludge and its decomposition products are concentrated and discharged from the upper pipe 16, the concentration of sludge and its decomposition products in the drain can be sufficiently reduced. By adjusting the amount of drain discharged from the pipe 18, the height of the interface between the liquid layer 40 and the foam layer 20 in the reaction tank 10 can be controlled. The drain may be sent to, for example, a water treatment device in a sewage treatment plant.

  In the reaction tank 10, the volume ratio of the foam layer 20 to the liquid layer 40 may be, for example, 2 to 8, or 3 to 7. If this volume ratio becomes too small, the decomposition and concentration of sludge does not proceed sufficiently in the foam layer 20, and the amount of water flowing out to the defoaming tank 30 tends to increase. On the other hand, if the volume ratio becomes too large, the reaction between ozone and sludge does not proceed sufficiently in the liquid layer 40 and the amount of sludge accompanying the drain discharged from the pipe 18 tends to increase.

  The liquid supply unit 12 supplies a sludge-containing liquid into the foam layer 20 formed in the reaction tank 10. The liquid supply part 12 should just be a structure which can supply a sludge containing liquid in the inside of the foam layer 20. FIG.

  FIG. 2 is a schematic diagram showing an enlarged cross section of the foam 21 included in the foam layer 20. As shown in FIGS. 2 (A) and 2 (B), the foam 21 is composed of a foam main body 22, sludge particles 24 adhering to the periphery of the foam main body 22, and a decomposition product 26 generated by decomposition of the sludge particles 24. And water 28 attached around the foam body 22. The foam body 22 is formed by surrounding the gas containing ozone supplied from the gas supply unit 50 to the liquid layer 40 with the liquid organic matter contained in the sludge and the sludge decomposition product. The sludge particle 24 is, for example, SS, and the decomposition product 26 is, for example, TDS. The decomposition product 26 is generated by a reaction between ozone and the sludge particles 24 and may be integrated with the foam main body 22 after the generation.

  Water 28 adheres on the surface of the foam main body 22. The water 28 rises in the foam layer 20 together with the foam body 22. In the water 28 and the foam main body 22, ozone is dissolved. At least a part of the sludge particles 24 contained in the sludge-containing liquid flowing down along the surface of the foam 21 adheres to the surface of the foam main body 22. In the foam layer 20 of the reaction tank 10, the dissolved ozone and the sludge particles 24 can efficiently contact with each other on the surface of the foam main body 22, so that the decomposition reaction of the sludge particles 24 proceeds sufficiently. In addition, the sludge particles 24 adhering to the surface of the foam main body 22 react with dissolved ozone while the foam layer 20 is raised. Thereby, the density | concentration of the decomposition product 26 increases toward the upper direction of the foam layer 20. As shown in FIG.

  FIG. 2A shows the bubbles 21 of the bubble layer 20 at a position higher than that in FIG. As the foam 21 ascends the foam layer 20, the water 28 attached to the foam body 22 falls due to the action of gravity. On the other hand, the sludge particles 24 and the decomposition product 26 rise together with the foam main body 22 while adhering to the surface of the foam main body 22 due to actions such as liquid crosslinking force and surface tension. For this reason, as shown in FIGS. 2 (A) and 2 (B), the higher the position of the foam layer 20, the more the water 28 decreases and the concentration of the sludge particles 24 and the decomposition products 26 increases. Thus, in the foam layer 20, the sludge particles 24 and the decomposition product 26 are concentrated, and the sludge and the decomposition product and water can be separated with high accuracy.

  As shown in FIG. 1, the upper part of the reaction tank 10 and the upper part of the defoaming tank 30 are connected by a pipe 16. The foam-like fluid containing the bubbles 21 is discharged from the reaction tank 10 by the pipe 16 connected to the upper part of the reaction tank 10. The foam-like fluid discharged from the reaction tank 10 includes foam 21 containing sludge decomposition product 26, sludge particles 24, and water 28, as shown in FIG. 2.

  The defoaming tank 30 includes a nozzle 60 for supplying a foam-like fluid containing the bubbles 21 to the inside thereof. The nozzle 60 is connected to the downstream side of the pipe 16. After the foam-like fluid discharged from the reaction tank 10 flows through the pipe 16 and the nozzle 60, the liquid in the liquid layer 40 </ b> A staying in the defoaming tank 30 from the discharge port 61 formed at the tip of the nozzle 60. Discharged. The defoaming tank 30 breaks and reduces the bubbles 21 contained in the foam-like fluid. The liquid layer 40 </ b> A in the defoaming tank 30 may be prepared by accumulating liquid contained in the fluid from the reaction tank 10, or may be prepared by separately introducing water into the defoaming tank 30.

  The discharge port 61 of the nozzle 60 is located in the liquid layer 40 </ b> A in the defoaming tank 30. For this reason, the foam-like fluid which distribute | circulated the nozzle 60 is discharged in the liquid layer 40A. The discharged foamy fluid collides with the liquid layer 40A. At least a part of the bubbles 21 included in the fluid is broken by an impact caused by the collision with the liquid layer 40A. In this way, the bubbles 21 contained in the fluid are reduced in the defoaming tank 30 (defoaming step).

  When the foam 21 is broken, the water 28, the decomposition product 26 and the sludge particles 24 contained in the foam 21 shown in FIG. 2 remain in the liquid layer 40 </ b> A. That is, the water 28, the decomposition product 26, and the sludge particles 24 form the liquid layer 40A. The foam 21 discharged from the discharge port 61 of the nozzle 60 and not broken even when it collides with the liquid layer 40A rises in the liquid layer 40A, and the foam layer 20A is placed above the liquid layer 40A in the defoaming tank 30. Form. The height of the liquid layer 40 </ b> A is adjusted by the amount of fluid discharged from the pipe 34 connected to the lower part of the defoaming tank 30. The fluid discharged from the pipe 34 includes sludge decomposition products, water, and sludge particles.

  The foam 31 that forms the foam layer 20 </ b> A contains the same components as the foam 21 that forms the foam layer 20 in the reaction tank 10. However, in the process in which the bubbles 31 collide with the liquid layer 40A and rise in the liquid layer 40A, the contents of the water 28, the decomposition product 26, and the sludge particles 24 are reduced. For this reason, the bubbles 31 in the defoaming tank 30 disappear faster than the bubbles 21 in the reaction tank 10. In this way, the bubbles 21 and the bubbles 31 can be reduced smoothly in the defoaming tank 30. As a result, the defoaming tank 30 can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  FIG. 3 is a view showing a modification of the defoaming tank provided in the ozone treatment apparatus. The defoaming tank 32 is a nozzle 63A, 63B, 63C (hereinafter referred to as “discharging foam”) that discharges the foam-like fluid discharged from the reaction tank 10 and flowing through the pipe 16 into the liquid layer 40A formed below the defoaming tank 32. , Collectively referred to as “nozzle 63”) and nozzle 66. The nozzle 63 and the nozzle 66 are connected to a pipe body 62 connected to the downstream side of the pipe 16.

  The fluid flow path in the tube body 62 is thicker than the fluid flow paths in each of the nozzle 63 and the nozzle 66. The cross-sectional area of the tube body 62 is preferably larger than the total cross-sectional area of the nozzle 63 and the nozzle 66 when viewed in a cross section perpendicular to the fluid flow direction. Thereby, the velocity of the fluid flowing through the nozzle 63 and the nozzle 66 can be made larger than the flow velocity of the fluid flowing through the tube body 62. Accordingly, the fluid can be ejected vigorously into the liquid layer 40A to cause the bubbles 21 to collide with the liquid layer, and the bubbles 21 can be easily broken.

  FIG. 4 is a view of the nozzles 63A, 63B, and 63C when viewed from above in the defoaming tank 32. FIG. As shown in FIGS. 3 and 4, the plurality (four) of nozzles 63 </ b> A are connected to the tube body 62 so as to expand radially along the horizontal direction around the tube body 62. Thus, by providing the nozzles 63A radially, fluid is discharged radially from the plurality of nozzles 63A. As a result, the contact between the discharged bubbles 21 is suppressed, and the contact frequency between the bubbles 21 and the liquid layer 40A can be increased.

  Similarly to the nozzle 63A, the plurality of (four) nozzles 63B and 63C are connected to the tube body 62 so as to expand radially along the horizontal direction with the tube body 62 as the center. The nozzles 63A, 63B, and 63C are arranged in this order along the longitudinal direction of the tube body 62 at a predetermined interval from the upstream side to the downstream side. Thereby, the contact between the bubbles 21 discharged from the nozzles 63A, 63B, and 63C can be suppressed, and the contact frequency between the bubbles 21 and the liquid layer 40A can be further increased. Thereby, it can further promote that the bubble 21 breaks.

  FIG. 5 is a view of the nozzles 63 </ b> A, 63 </ b> B, 63 </ b> C, 66 when viewed from below inside the defoaming tank 32. As shown in FIGS. 3 and 5, the plurality (four) of nozzles 66 are connected to the tip of the tube body 62 via a support member 67. The nozzle 66 is inserted and fixed in a hole formed in the support member 67, for example. The nozzle 63 discharges fluid toward the outer side in the radial direction of the tube body 62, while the nozzle 66 discharges fluid toward the lower side in the central axis direction of the tube body 62. Thus, by providing the nozzle 63 and the nozzle 66 that discharge the fluid in different directions, the bubble 21 and the liquid layer 40A can be sufficiently brought into contact with each other.

  As for the nozzle 63C and the nozzle 66, the flow path in a front-end | tip part may be narrower than the flow path in a base end part. Thus, by making the inner diameters at the distal end portions of the nozzles 63A, 63B, 63C, 66 smaller than the inner diameter at the proximal end portion, it is possible to eject the foamy fluid vigorously at a high speed toward the liquid layer 40A.

  The discharge ports 61 of the nozzle 63 and the nozzle 66 are located inside the liquid layer 40 </ b> A in the defoaming tank 32. For this reason, the foam-like fluid which circulated through the nozzle 63 and the nozzle 66 is discharged into the liquid layer 40A. The discharged foamy fluid collides with the liquid layer 40A. At least a part of the bubbles 21 contained in the fluid is broken by an impact caused by the collision with the liquid layer 40A. In this way, the bubbles 21 contained in the fluid are reduced in the defoaming tank 32 (defoaming step).

  On the other hand, the foam 21 discharged from the discharge ports 61 of the nozzle 63 and the nozzle 66 and not broken even when colliding with the liquid layer 40A rises in the liquid layer 40A and is above the liquid layer 40A in the defoaming tank 32. The foam layer 20A is formed. In the defoaming tank 30, the volume ratio of the foam layer 20A to the liquid layer 40A may be, for example, 0.1 to 3, or 0.5 to 2. When this volume ratio becomes too large, bubbles tend to overflow from the defoaming tank 30. In this case, for example, the supply amount of the sludge-containing liquid from the liquid supply unit 12 to the reaction tank 10 is reduced.

  The foam 31 that forms the foam layer 20 </ b> A contains the same components as the foam 21 that forms the foam layer 20 in the reaction tank 10. However, in the process in which the bubbles 31 collide with the liquid layer 40A and rise in the liquid layer 40A, the contents of the water 28, the decomposition product 26, and the sludge particles 24 are reduced. For this reason, the bubbles 31 in the defoaming tank 30 disappear faster than the bubbles 21 in the reaction tank 10. Thus, in the defoaming tank 30, the bubbles 21 (bubbles 31) can be reduced smoothly. As a result, the defoaming tank 32 can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  The defoaming tank 32 has a communication portion 33 that communicates the inside and the outside of the defoaming tank 32. By having the communication part 33, the internal pressure of the defoaming tank 32 can be reduced. Thereby, the bubbles 31 in the bubble layer 20A can be reduced more smoothly. The communication unit 33 is not particularly limited as long as the gas inside the defoaming tank 32 and the outside atmosphere can flow. For example, a through hole penetrating the upper surface of the defoaming tank 32 may be used, or a structure in which a pipe is inserted into the through hole may be used. The valve may be opened to the atmosphere when a predetermined internal pressure is reached.

  The internal pressure of the defoaming tank 32 is preferably not more than atmospheric pressure from the viewpoint of promoting the reduction of the bubbles 31 in the foam layer 20A. Since the internal pressure of the reaction tank 10 to which the gas containing ozone is supplied from the gas supply unit 50 tends to exceed the atmospheric pressure, the internal pressure of the defoaming tank 32 is lowered by providing the communication part 33 in the defoaming tank 32. be able to. The defoaming tank 32 may be provided with a pressure gauge, a pressure adjustment valve, and a pressure control unit for controlling the internal pressure.

  The nozzle 63 and the nozzle 66 preferably discharge the foam-like fluid so that the gas discharge speed is preferably 2 m / second or more, more preferably 5 m / second or more. By increasing the gas discharge speed in this way, it is possible to vigorously discharge the foam-like fluid into the liquid layer 40A. As a result, the bubbles 21 collide with the liquid layer 40A and are easily broken. Therefore, the reduction of the bubbles 21 can be further promoted. Moreover, it can suppress that the nozzle 63 and the nozzle 66 are obstruct | occluded with the sludge particle | grains 24 grade | etc., Contained in foam-like fluid.

In the present specification, the gas discharge speed S [m / s] in the defoaming tank 32 (30) can be obtained by the following equation (1).
S = Q _G / [A × {Q _G / (Q _G + Q _L )}] (1)
In Formula (1), Q _G indicates the flow rate [m ³ / sec] of the gas supplied from the gas supply unit 50, and Q _L indicates the flow rate of the fluid discharged from the defoaming tank 32 (30) by the pipe 34 [ m ³ / sec], and A represents the total value [m ² ] of the opening areas of the discharge ports 61 of the nozzle 63 and the nozzle 66.

  As described above, the defoaming tank 32 is different from the defoaming tank 30 according to the above-described embodiment in that the defoaming tank 32 includes the pipe body 62, the nozzle 63, the nozzle 66, and the communication portion 33. As described above, the defoaming tank 32 includes a plurality of nozzles that discharge a foam-like fluid to the liquid layer 40A. The plurality of nozzles are provided so as to discharge the foam-like fluid in different directions. For this reason, it can reduce that foam-like fluids contact, and can make foam-like fluid and 40 A of liquid layers contact efficiently. Needless to say, the defoaming tank 30 may be provided with the pipe body 62, the nozzle 63 and the nozzle 66, or the communication portion 33.

  The shapes and numbers of the nozzles 63A, 63B, 63C and the nozzle 66 are not limited to those shown in FIGS. For example, the number of nozzles 63A, 63B, 63C and nozzles 66 is not limited to four, and may be three or less, or five or more. Further, the nozzles 63A, 63B, and 63C do not have to have the same extending direction when viewed from above as shown in FIG. It is not essential to provide a plurality of nozzles 63A, 63B, and 63C at different heights as shown in FIGS. Further, the lengths of the nozzles 63 </ b> A do not have to be the same, and the lengths may be changed according to the shape of the defoaming tank 32. The same applies to the nozzle 63B and the nozzle 63C.

  FIG. 6 is a view showing a modification of the nozzle provided in the defoaming tank. The nozzle 60A is connected to, for example, the downstream side of the pipe 16 in FIG. Four partition plates 68 are attached to the tip of the nozzle 60A. The tip of the partition plate 68 protrudes below the discharge port 61 of the nozzle 60A. The tip of the partition plate 68 is attached to the support member 69. 1 is discharged from the discharge port 61 toward the lower support member 69 through the nozzle 60A of FIG.

  Bubbles contained in the bubble-like fluid discharged from the discharge port 61 collide with the support member 69. Bubbles can be reduced by the impact of this collision. The partition plate 68 has a function of partitioning the flow path of the fluid discharged from the discharge port 61 and suppressing bubbles included in the foam-like fluid from contacting each other. This reduces the contact between the bubbles and promotes the bubbles to contact the liquid layer 40A or the partition plate 68. Therefore, the foam reduction can be further promoted by having the partition plate 68. The shape and number of the partition plates 68 are not limited to the embodiment shown in FIG. A partition plate will not be specifically limited if it is a structure which partitions a flow path and can contact a bubble.

  The nozzle 60 </ b> A has a throttle portion 64 that narrows the flow path of the foam-like fluid upstream of the discharge port 61. The nozzle 60 </ b> A can have a narrower flow path on the downstream side (front end side) than on the upstream side (base end side) by having the throttle portion 64. As a result, it is possible to increase the discharge speed of the bubble-like fluid and promote the breakage of the bubbles contained in the fluid.

  FIG. 7 is a diagram illustrating an example of a sludge treatment system to which the ozone treatment apparatus 100 is applied. The sludge treatment system 1 is applied to, for example, a sewage treatment plant. The sludge treatment system 1 includes a water treatment device 80 for treating sewage, an ozone treatment device 100 and a digestion fermentation device 70 for treating sludge-containing liquid generated in the water treatment device 80 to reduce sludge, and sludge dewatering. And a sludge treatment apparatus 90 that performs drying.

  In the ozone treatment apparatus 100, solid fuel and phosphorus fertilizer can be efficiently produced from sewage by separating sludge and its decomposition products and water while decomposing sludge contained in the sludge-containing liquid. The liquid concentrate discharged from the pipe 34 in the defoaming tank 30 (32) of the ozone treatment apparatus 100 may be supplied to the digestion fermentation apparatus 70 to produce methane. The drain containing water discharged from the reaction tank 10 of the ozone treatment apparatus 100 through the pipe 18 and the fluid discharged from the defoaming tank 30 (32) through the pipe 34 may be supplied to the water treatment apparatus 80. In addition, the use of the ozone treatment apparatus 100 is not limited to the sludge treatment system 1 of FIG. 7, It can apply to the various systems which process a sludge containing liquid.

  The sludge treatment method of this embodiment is provided in the reaction tank 10 on the downstream side of the reaction tank 10 in a reaction step in which a sludge-containing liquid is treated with ozone to obtain a foam-like fluid containing a sludge decomposition product. The defoaming tank 30 (32) has a defoaming step for reducing bubbles contained in the fluid. In the defoaming step, the foam-like fluid is discharged using the nozzles 60 (63, 66) provided in the defoaming tank 30 (32) inside the liquid layer 40A in the defoaming tank 30 (32) obtained from the fluid. Discharge. Each process can be performed based on description of the above-mentioned ozone treatment apparatus and a defoaming tank. Another arbitrary step may be performed before, after, or simultaneously with each step.

  In such a sludge treatment method, the foam-like fluid obtained in the reaction process is discharged into the liquid layer 40A in the defoaming tank 30 (32) using the nozzle 60 (63, 66) in the defoaming process. ing. By discharging into the liquid layer 40A in this way, bubbles contained in the fluid can be smoothly reduced as compared with the case of discharging into the bubble layer 20A or the gas above it. Therefore, the defoaming tank 30 (32) can be made compact, and the labor and utility costs required for sludge treatment can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment at all. For example, although the above-mentioned ozone processing apparatus is comprised with the reaction tank 10, the defoaming tank 30 (32), and the piping 16 which connects these, you may have arbitrary facilities in addition to these. For example, a tank may be provided between the reaction tank 10 and the defoaming tank 30 (32) for reducing fluctuations in the foam fluid. According to the height of the foam layer 20A in the defoaming tank 30 (32), it has a flow rate control valve and a flow rate control unit for adjusting the amount of foam-like fluid supplied to the defoaming tank 30 (32). It may be. Moreover, in order to accelerate | stimulate defoaming, you may provide the antifoamer supply apparatus which supplies an antifoamer in the defoaming tank 30 (32).

  The content of the invention will be described in detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
An ozone treatment apparatus including a reaction tank 10 and a defoaming tank 30 as shown in FIG. 1 was prepared. The defoaming tank 30 had a box shape (length × width × height = 0.4 m × 0.7 m × 0.3 m). The sludge-containing liquid generated from the sewage water treatment apparatus by the liquid supply unit 12 was supplied to the reaction tank 10 at 70 L / min / m ² , and a gas containing ozone was supplied from the gas supply unit 50 to the reaction tank 10. The supply amount of ozone was 68 mg per 1 g of suspended matter (SS) contained in the sludge-containing liquid.

  Foam was continuously discharged from the pipe 16 connected to the upper part of the reaction tank 10 and drain was discharged from the pipe 18 connected to the lower part of the reaction tank 10. The drain discharge amount was adjusted, and the height of the interface between the liquid layer 40 and the foam layer 20 in the reaction tank 10 was adjusted to be constant.

  The nozzle 60 in the defoaming tank 30 had a cylindrical shape as shown in FIG. The total value (A) of the inner diameter of the nozzle outlet, the number of nozzles, and the opening area of the nozzle outlet was as shown in Table 1.

Sludge treatment was performed to form a liquid layer 40A on the lower part of the defoaming tank 30, and a foam layer 20A on the liquid layer 40A. The initial height of the liquid layer 40A (solubilized sludge) was set to 0.1 m so that the foam-like fluid discharged from the nozzle 60 was supplied into the liquid layer 40A. The supply flow rate (Q _G ) of the gas containing ozone from the gas supply unit 50, the flow rate (Q _L ) of the fluid discharged from the lower part of the defoaming tank 30, the discharge speed (S) of the gas, and the pressure of the reaction tank are It was as shown in Table 1.

  After performing the treatment for a predetermined time without discharging the fluid from the pipe 34, the increase amount of the liquid layer 40A in the defoaming tank 30 was obtained. And the volume ratio of the said increase of the liquid layer 40A with respect to the total amount of the foam-like fluid supplied to the defoaming tank 30 within the said predetermined time was computed. The results are shown in Table 1 as the liquefaction rate.

(Example 2)
As the liquid layer 40A of the defoaming tank 30, the sludge treatment was performed in the same manner as in Example 1 except that water was charged instead of the decomposed sludge and the treatment was performed for a predetermined time. And the liquefaction rate was calculated | required like Example 1. FIG. The results were as shown in Table 1.

(Comparative Example 1)
Example except that a foam-like fluid discharged from the nozzle was supplied into the space above the defoaming tank (above the liquid layer 40A) using a nozzle shorter than that in Example 1. The sludge treatment was performed in the same manner as in 1. And the liquefaction rate was calculated | required like Example 1. FIG. The results were as shown in Table 1.

(Comparative Example 2)
A sludge treatment was performed in the same manner as in Comparative Example 1 except that a stirrer having a stirring shaft and a stirring blade was attached to the defoaming tank 30, and the sludge treatment was performed while stirring the foam layer 20A with the stirring blade. . Also in Comparative Example 2, the foam fluid discharged from the nozzle was supplied into the space above the defoaming tank (above the liquid layer 40A). And the liquefaction rate was calculated | required like Example 1. FIG. The results were as shown in Table 1.

( Reference Example 3)
An ozone treatment apparatus including a reaction tank 10 and a defoaming tank 30 having a size larger than that of Example 1 was prepared. The defoaming tank 30 had a substantially cylindrical shape (inner diameter: about 1 m, height: about 1.8 m). This ozone treatment apparatus also had an apparatus configuration as shown in FIG. The sludge treatment was performed in the same manner as in Example 1 using this ozone treatment apparatus. That is, the foam-like fluid discharged from the nozzle 60 was supplied into the liquid layer 40 </ b> A of the defoaming tank 30. And the liquefaction rate was calculated | required like Example 1. FIG. The results were as shown in Table 1.

Example 4
1 except that a defoaming tank 32 having nozzles 63 and 66 and a tube body 62 as shown in FIGS. 3, 4 and 5 is used instead of the defoaming tank 30 having a nozzle 60 as shown in FIG. The sludge treatment was performed in the same manner as in Reference Example 3. The foam-like fluid discharged from the nozzles 63 and 66 was supplied into the liquid layer 40 </ b> A of the defoaming tank 32. Then, the liquefaction rate was determined in the same manner as in Reference Example 3. The results were as shown in Table 1.

(Example 5)
The sludge treatment was performed in the same manner as in Example 4 except that the flow rate of the gas containing ozone supplied from the gas supply unit 50 was changed. The foam-like fluid discharged from the nozzles 63 and 66 was supplied into the liquid layer 40 </ b> A of the defoaming tank 32. Then, the liquefaction rate was determined in the same manner as in Reference Example 3. The results were as shown in Table 1.

From the comparison of Examples 1 and 2 and Comparative Examples 1 and 2 in Table 1, it was confirmed that the liquefaction rate can be increased by discharging a foam-like fluid into the liquid layer in the defoaming tank. It was confirmed that the liquid layer may be water or decomposed sludge. From the result of Comparative Example 2, it was confirmed that foam could not be reduced smoothly even if stirring was performed using a stirring blade. In Reference Example 3 and Examples 4 and 5, the liquefaction rate was higher than that in Comparative Examples 1 and 2. From a comparison between Reference Example 3 and Examples 4 and 5, it was confirmed that it is effective to reduce the inner diameter of the nozzle outlet and to increase the gas discharge speed.

  DESCRIPTION OF SYMBOLS 1 ... Sludge treatment system, 10 ... Reaction tank, 12 ... Liquid supply part, 20, 20A ... Foam layer, 21 ... Foam, 22 ... Foam body, 24 ... Sludge particle, 26 ... Decomposition product, 28 ... Water, 30, 32 Defoaming tank, 33 ... Communication part, 40, 40A ... Liquid layer, 50 ... Gas supply part, 51 ... Gas, 52 ... Gas diffuser, 54 ... Pipe part, 55 ... Mixing part, 56 ... Ozone generating part, 58 ... Air supply unit, 61 ... discharge port, 62 ... tube, 60, 63, 63A, 63B, 63C, 66 ... nozzle, 64 ... throttling unit, 70 ... digestion fermentation device, 80 ... water treatment device, 90 ... sludge treatment device , 100 ... ozone treatment device.

Claims (15)

A defoaming tank that is provided on the downstream side of a reaction tank that treats sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and reduces bubbles contained in the fluid,
A nozzle for discharging the fluid into the liquid layer containing the decomposition product ;
The nozzle is provided on the upstream side of the nozzle and connected to a tube body thicker than the nozzle, and the nozzle is connected to the tube body in a plurality,
A plurality of said nozzle extends radially from the tubular body, that discharges the fluid from the tip, Shoawaso. A defoaming tank that is provided on the downstream side of a reaction tank that treats sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and reduces bubbles contained in the fluid,
A nozzle for discharging the fluid into the liquid layer containing the decomposition product;
A defoaming tank in which a partition plate that partitions the flow path of the fluid discharged from the discharge port of the nozzle is attached to the tip of the nozzle. A defoaming tank that is provided on the downstream side of a reaction tank that treats sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and reduces bubbles contained in the fluid,
A nozzle for discharging the fluid into the liquid layer containing the decomposition product;
The reaction tank includes a gas supply unit that supplies a gas containing the ozone,
The nozzle, the discharge velocity of the gas ejecting the fluid such that 2m / sec or more, anti Awaso.   The defoaming tank according to any one of claims 1 to 3, wherein the nozzle has a throttle portion that narrows the flow path of the fluid on the downstream side of the upstream side. The reaction tank includes a gas supply unit that supplies a gas containing the ozone,
The defoaming tank according to claim 1 or 2, wherein the nozzle discharges the fluid so that a discharge speed of the gas is 2 m / second or more.   The said defoaming tank is a defoaming tank as described in any one of Claims 1-5 which has a communicating part connected to air | atmosphere.   The defoaming tank according to any one of claims 1 to 6, wherein the internal pressure is equal to or lower than atmospheric pressure. A reaction tank for treating a sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and a defoaming tank provided on the downstream side of the reaction tank for reducing bubbles contained in the fluid. An ozone treatment device comprising:
The defoaming tank includes a nozzle that discharges the fluid into a liquid layer containing the decomposition product ,
The nozzle is provided on the upstream side of the nozzle and connected to a tube body thicker than the nozzle, and the nozzle is connected to the tube body in a plurality,
The plurality of nozzles extend radially from the tubular body, and discharge the fluid from the tip thereof . A reaction tank for treating a sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and a defoaming tank provided on the downstream side of the reaction tank for reducing bubbles contained in the fluid. An ozone treatment device comprising:
The defoaming tank includes a nozzle that discharges the fluid into a liquid layer containing the decomposition product,
An ozone treatment apparatus, wherein a partition plate for partitioning a flow path of the fluid discharged from the discharge port of the nozzle is attached to a tip portion of the nozzle. A reaction tank for treating a sludge-containing liquid with ozone to obtain a foam-like fluid containing a sludge decomposition product, and a defoaming tank provided on the downstream side of the reaction tank for reducing bubbles contained in the fluid. An ozone treatment device comprising:
The defoaming tank includes a nozzle that discharges the fluid into a liquid layer containing the decomposition product,
The reaction tank includes a gas supply unit that supplies a gas containing the ozone,
The ozone treatment apparatus, wherein the nozzle discharges the fluid so that a discharge speed of the gas is 2 m / second or more . The reaction tank includes a gas supply unit that supplies a gas containing the ozone,
The ozone treatment apparatus according to claim 8 or 9, wherein the nozzle discharges the fluid so that a discharge speed of the gas is 2 m / second or more . In the reaction tank, a reaction step of treating the sludge-containing liquid with ozone to obtain a foam-like fluid containing sludge decomposition products;
In the defoaming tank provided downstream from the reaction tank, the defoaming step to reduce the foam contained in the fluid,
The antifoam step, the inside of the liquid layer containing the hydrolyzate of the defoaming tank, the eject the fluid using a nozzle provided in the defoaming tank, wherein the nozzle is upstream from the nozzle A plurality of nozzles connected to the pipe body, the plurality of nozzles extending radially from the pipe body, and the fluid from the tip thereof discharging that, sludge treatment methods. In the reaction tank, a reaction step of treating the sludge-containing liquid with ozone to obtain a foam-like fluid containing sludge decomposition products;
In the defoaming tank provided downstream from the reaction tank, the defoaming step to reduce the foam contained in the fluid,
In the defoaming step, the fluid is discharged into the liquid layer containing the decomposition product in the defoaming tank using a nozzle provided in the defoaming tank, and the nozzle is disposed at the tip of the nozzle. A sludge treatment method in which a partition plate for partitioning the flow path of the fluid discharged from the discharge port is attached. In the reaction tank, a reaction step of treating the sludge-containing liquid with ozone to obtain a foam-like fluid containing sludge decomposition products;
In the defoaming tank provided downstream from the reaction tank, the defoaming step to reduce the foam contained in the fluid,
In the defoaming step, the fluid is discharged into the liquid layer containing the decomposition product in the defoaming tank using a nozzle provided in the defoaming tank,
In the defoaming step, the nozzle, the discharge rate of the gas containing the ozone is supplied to discharge the fluid so that 2m / sec or more in the reaction step, sludge treatment method. The sludge treatment according to claim 12 or 13, wherein, in the defoaming step, the nozzle discharges the fluid so that a discharge speed of the gas containing ozone supplied in the reaction step is 2 m / second or more. Method.

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