WO2007037646A1

WO2007037646A1 - Plant for wastewater treatment

Info

Publication number: WO2007037646A1
Application number: PCT/KR2006/003915
Authority: WO
Inventors: Hong-Bok Choi; Jae-Ki Lee; Ju-Hyung Park; Eun-Ju Choi; Jeong-Rae Kim
Original assignee: Ecodays Co., Ltd.
Priority date: 2005-09-29
Filing date: 2006-09-29
Publication date: 2007-04-05
Also published as: KR100686191B1

Abstract

A biochemical plant for wastewater treatment is disclosed. The wastewater treatment plant includes a reaction tank into which wastewater and a gas are introduced; more than one gas separation unit dividing an internal space of the reaction tank into upper and lower sections to define a residing space by ascending gas so as to increase a residing time of gas and an amount of dissolved oxygen by increasing a contact area of the wastewater and gas, to incur a concentration difference by a difference of molecular weight of gas, and to increase the concentration of gas caused by a catalyst reaction thereby activating an oxidizing reaction; and a means for biochemical treatment provided at a lower portion of the gas separation unit, and for forming a catalyst layer to activate the ozone reaction so as to generate a biochemical reaction while the ozone is contacted with wastewater.

Description

Description PLANT FOR WASTEWATER TREATMENT

Technical Field

[1] The present invention relates to a wastewater treatment plant, and more particularly, to a wastewater treatment plant that can improve the efficiency of wastewater treatment by providing a catalyst member capable of activating an ozone reaction in a reactor tank, thereby enhancing the reaction speed of ozone through a biochemical reaction. Background Art

[2] Generally, wastewater treatment is a process for converting polluted matter contained in water into stable matter through a microbiological reaction or a chemical oxidation/reduction reaction and for separating untreated residual matter.

[3] Therefore, the wastewater treatment is a technology for enhancing water quality and stabilizing and separating organic matter and nutritional matter. To date, the wastewater treatment has been performed by a biological treatment process and a biochemistry treatment process. Further, one of the biochemistry treatment processes is the method of ozone treatment.

[4] However, a conventional ozone treatment process has a disadvantage in that since it is difficult to form free radicals (OH), it is difficult to realize effective wastewater treatment.

[5] Also, since there is a limitation in time and area with which the ozone gas and wastewater contact each other, the speed of dissolution of the ozone is decreased. Disclosure of Invention Technical Problem

[6] The present invention has been made in an effort to provide a biochemical plant for wastewater treatment that can improve the efficiency of wastewater treatment by providing a catalyst member capable of activating the ozone reaction in a reactor, thereby enhancing the reaction speed of the ozone through biochemical reaction.

[7] Another advantage provided by an exemplary embodiment of the present invention is to increase the residing time of gas within a reactor by forming a residential space for gas ascending by buoyant force so as to activate the reaction between gas and wastewater.

[8] Another advantage provided by an exemplary embodiment of the present invention is that it can maximize an ozone concentration contacting wastewater by separating gas with oxygen and ozone residing in the gas separating unit.

[9] Another advantage provided by an exemplary embodiment of the present invention is that it can maximize an amount of free radicals by inducing the continuous reaction in the PFR type of reaction tank.

[10] Another advantage provided by an exemplary embodiment of the present invention is to minimize the ozone concentration exhausting in an insoluble state.

[11] Another advantage provided by an exemplary embodiment of the present invention is to increase the efficiency by activating the biochemical reaction and by injecting air having a low oxidizing force. Another advantage provided by an exemplary embodiment of the present invention is to provide a UV lamp and ozone gas. Technical Solution

[12] To achieve the above objectives, the present invention includes a wastewater treatment plant including a reaction tank into which wastewater and a gas are introduced; more than one gas separation unit dividing an internal space of the reaction tank into upper and lower sections to define a residing space for ascending gas so as to increase a residing time of the gas and an amount of dissolved oxygen by increasing a contact area of the wastewater and gas, to incur a concentration difference by a difference of molecular weight of the gas, and to increase the concentration of gas caused by a catalyst reaction, thereby activating an oxidizing reaction; and a means for biochemical treatment provided at a lower portion of the gas separation unit, and for forming a catalyst layer to activate the ozone reaction so as to generate a biochemical reaction while the ozone is in contact with wastewater.

Advantageous Effects

[13] As described above, the inventive wastewater treatment plant has advantages as follows. [14] Firstly, since the gas is reacted with the catalyst layer, the ozone concentration is increased so as to realize high efficiency of wastewater treatment. [15] Secondly, since the reaction tank has a predetermined space therein, it may increase the residing time in which the gas and wastewater reside therein. [16] Thirdly, in the conventional treatment process, since the space of the reaction tank is mostly filled with oxygen, it is difficult to form free radicals (OH). However, in the present invention, by separating the gas using a weight difference in the space of the reaction tank, it may maximize the reaction concentration of the ozone around the wastewater surface. [17] Fourthly, since the reaction tank is a PFR-Type (plug flow reactor), it is possible to realize the continuous reaction so as to maximize the amount of OH free radicals. [18] Fifthly, by increasing the residing time of the ozone, and by repeated contact between the gas and wastewater, it may minimize the ozone concentration exhausting outside in an insoluble state. [19] Sixthly, by exhausting the gas in the gas separation unit quickly, it can clean the substance matter at a coating portion of catalyst.

[20] Seventhly, in the case of using a UV lamp, it is possible to achieve similar effects to the ozone case. Brief Description of the Drawings

[21] FIG. 1 is a perspective view showing a biochemical plant for wastewater treatment according to a preferred embodiment of the present invention;

[22] FIG. 2 is a side sectional view of a biochemical plant for wastewater treatment;

[23] FIG. 3 is a partly enlarged perspective view of a portion "A" of FIG. 1;

[24] FIG. 4 is a sectional view of a modified example of a fluid flowing tube of FIG. 3;

[25] FIG. 5 is a perspective view showing a catalyst plate depicted in FIG. 1;

[26] FIG. 6 is a perspective view showing a modified example of a catalyst plate depicted in FIG. 5;

[27] FIG. 7 is a side sectional view of a biochemical plant for wastewater treatment according to another preferred embodiment of the present invention. Best Mode for Carrying Out the Invention

[28] Preferred embodiments of the present invention will be described hereinafter in conjunction with the accompanying drawings. FIG. 1 is a perspective view showing a biochemical plant for wastewater treatment according to a preferred embodiment of the present invention, and FIG. 2 is a side sectional view of a biochemical plant for wastewater treatment.

[29] As shown in FIGS. 1 and 2, the inventive biochemical plant for wastewater treatment includes a reaction tank 10 into which wastewater and a gas are introduced; more than one gas separation unit 12 for decomposing contaminants by dividing the space of the reaction tank 10 into upper and lower sections, moving the introduced wastewater and gas bubbles upward in order of density, and increasing an amount of dissolved gas so as to activate the ozone reaction; and means for biochemical treatment 35 and 37 provided at a lower portion of the gas separation unit 12, and for forming a catalyst layer to activate the ozone reaction so as to generate a biochemical reaction while the ozone is contacted with the wastewater.

[30] In the above-described biochemical plant for wastewater treatment, a wastewater supply tube 22 and a gas supply tube 24 extend into a lower portion of the reaction tank 10.

[31] The wastewater is introduced into the reaction tank 10 via the wastewater supply tube 22. The gas supply tube 24 includes a tube 26 located inside the reaction tank 10, and spray tubes 28 mounted above the tube 26. The gas can be introduced into the reaction tank 10 through the gas supply tube 24, and accordingly, the gas sprayed from the spray tubes 24 generates micro bubbles. [32] The gas that is introduced through the gas supply tube 24 includes ozone, air, or nitrogen, and preferably, the gas includes ozone. [33] Accordingly, the wastewater introduced through the wastewater supply tube 22 is filled in the reaction tank 10 from the bottom of the tank, and the ozone gas introduced through the gas supply tube 24 moves upward as micro bubbles in the reaction tank 10. [34] At this point, an oxidizing agent such as ozone selectively includes ultraviolet rays or can use ozone and ultraviolet rays, simultaneously. [35] An exhaust tube 17 is provided at a lower portion of the reaction tank 10 to exhaust the sludge or the gas. [36] Also, a gas exhaust tube 14 and a treated water exhaust tube 15 are mounted on the reaction tank to exhaust the water and gas. [37] The treated water exhaust tube 15 is selectively provided at the lower portion or upper portion of the reaction tank 10 according to the physical properties. Also, the gas exhaust tube 14 is selectively provided at the lower portion or upper portion of the reaction tank 10. [38] The reaction tank 10 also includes a gas separation unit 12 therein, the gas separation unit 12 including at least one and preferably first and second gas separation parts 34 and 32. [39] Therefore, the wastewater and gas that are introduced from the lower portion of the reaction tank 10 move upward through the gas separation unit 12, and biochemical treatment occurs during that time. [40] At this point, the first and second gas separation parts 32 and 34 are identical to each other in a shape. Therefore, the description will be done just for the first gas separation part 32. [41] The first gas separation part 32, as shown in Figs. 1 through 3, divides the chamber of the reaction tank 10 into upper and lower sections, and includes at least one plate 36 provided with a plurality of through holes h, and a plurality of fluid flowing tubes 38 extending downward from the bottom of the plate 36 to allow the wastewater and air to pass therethrough. [42] In the above-described first gas separation unit 12, the plate 36 divides the chamber of the reaction tank 10 vertically into upper and lower sections, and the plurality of through holes h are formed at the plate 36 to allow the wastewater and air to pass therethrough.

[43] At least, one UV lamp can be arranged at a bottom of the plate 36, therefore, ultraviolet rays emitted from the UV lamp can induce the oxidizing reaction. [44] The plurality of fluid flowing tubes 38 are extended downward from the bottom of the plate 36. The plurality of fluid flowing tubes 38 have a space therein, and they communicate with the plurality of through holes h.

[45] Also, the plurality of fluid flowing tubes 38 are formed with an edge portion 40 at the lower portion thereof, and a first catalyst layer 42 is formed at a lower surface of the edge portion 40.

[46] The first catalyst layer 42 is formed at the lower surface of the edge portion 40 at a predetermined thickness, and includes the catalyst agent having strong oxidizing properties, e.g., oxidizing titanium.

[47] Accordingly, in this condition, since the wastewater passing the first catalyst layer

42 has a very high ozone concentration, it is possible to increase the generation of free radicals so as to increase the reaction speed between the wastewater and contamination materials. At this point, since the free radicals are a middle product in the reaction process, they can induce the fast reaction speed between the wastewater and contamination materials.

[48] The plurality of fluid flowing tubes 38 extend toward the bottom of the plate 36 by a predetermined length, and a water surface is formed in a lateral direction from the lower portion of the plurality of fluid flowing tubes 38, thereby defining residing spaces S enclosed by the fluid flowing tubes 38.

[49] That is, the gas such as the ozone ascending from the bottom of the reaction tank 10 is collected in the residing spaces S, and when a predetermined amount of the gas is collected in the residing spaces S, the gas presses the wastewater downward so as to form the wastewater level Wl.

[50] At this point, the wastewater level is formed in a lateral direction from the lower portion of the fluid flowing tube 38, and when the wastewater level goes downwards below the lateral line, the gas collected in the residing spaces S is dispersed in all directions by pressure to be directed to the plurality of fluid flowing tubes 38 and moves upward therethrough.

[51] In the above description, the gas is collected in the residing spaces S so as to increase the residing time of the gas, and since the gas contacts the wastewater surface during the residing time, the biochemical reaction can be activated.

[52] In addition, the distance between the wastewater level W and the first catalyst plate

35 is short. Therefore, the gas moves relatively fast between the wastewater line W and the first catalyst plate 35, the gas contacts the second catalyst layer 46 and the first catalyst layer 42 in turn, and the gas ascends toward the next separation unit.

[53] In this process, by forming a thin depth of the wastewater and PFR, since the gas and wastewater contact each other at a ratio of 1:1, it can induce high contact effects, high reaction speed, and high dissolved speed of the ozone.

[54] Further, the gas stored in the residing spaces S is in a state such that the oxygen and ozone are mixed, with the oxygen mostly occupying the spaces, preferably at over the 85%, and the rest is the ozone. At this point, by the difference of molecular weight between the oxygen and ozone, the ozone is located at the lower portion, thereby incurring the concentration difference. Accordingly, since the ozone having a high concentration is in contact with the wastewater surface, the free radicals are generated freely so at to maximize the reaction concentration of the ozone around the wastewater surface.

[55] Furthermore, since the gas ascending from the lower portion newly forms the gas residing spaces S, the fluidity of the wastewater can be further improved because of by ascending gas.

[56] In the above description, since the factors that can increase the reaction speed, e.g., concentration, contact effect, and pressure, are maintained at optimum conditions, the reaction can proceed efficiently. The materials that are generated from the reaction ascend, thereby maximizing the reaction efficiency and reaction effect.

[57] In the above description, although the shape of the fluid flowing tube is shown to be generally tube-shaped, the present invention is not limited to this case. For example, as shown in FIG. 4, an upper area of the fluid flowing tube 42 may be wider than the lower area thereof.

[58] The second gas separation parts 34 are identical to first gas separation parts 32 in shape. That is, the second gas separation parts 34 comprise a plate, a fluid flowing tube, and a catalyst layer.

[59] As shown in FIGS. 1 to 3, the means for biochemical treatment 35 and 37 include a first catalyst plate 35 arranged at a lower portion of the first gas separation unit 32, and a second catalyst plate 37 arranged at an upper portion of the second gas separation unit 37. Therefore, only a description for the first catalyst plate 35 will be presented.

[60] The first catalyst plate 35 is arranged below the first gas separation unit 32 by a predetermined distance.

[61] The first catalyst plate 35, as shown in FIG. 5, is preferably circular, and a plurality of pass holes 48 are formed therein.

[62] Therefore, while the gas is ascending from lower portion and passes through the holes 48 of the first catalyst plate 35, since the moving speed of the gas is reduced and the moving distance is increased, it is possible for the contacting time between the gas and the wastewater to be increased.

[63] The first catalyst plate 35 is connected to an inner side of the reaction tank 10 by a connecting bar 50 so as to be fixed at a predetermined position. A plurality of connecting bars 50 may be used.

[64] Also, the first catalyst plate 35 is formed with the second catalyst layer 46 at a surface thereof, and the second catalyst layer 46 is made of catalyst materials. The second catalyst layer 46 has the same physical properties as the first catalyst layer 35. [65] That is, the second catalyst layer 46 is formed at the lower surface and the upper surface of the first catalyst plate 35, and includes a catalyst having strong oxidizing properties. [66] Accordingly, it is possible to increase ozone concentration by the second catalyst layer 46, and to activate the generation of the free radicals (OH) so as to increase the reaction speed with a contaminated material such as wastewater. [67] Consequently, the first catalyst plate 35 increases the gas concentration so as to increase the reaction speed with the wastewater, thereby enhancing the treatment efficiency. [68] In particular, since the ozone concentration is maximized around the surface, it can significantly increase the reaction speed. [69] In the above description, although the second catalyst layer is formed at the entire surface of the first catalyst plate, the present invention is not limited to this case. For example, the second catalyst layer can be formed at either the upper surface or the lower surface of the first catalyst plate. [70] Also, although the first catalyst plate is circular, the present invention is not limited to this case, and it can be dished. [71] That is, as shown in FIG. 6, a first catalyst plate 58 includes a body 60 having a concave shape and formed with a plurality of the holes 62 therein, and an edge portion

64 formed at an upper portion of the body 60 with a predetermined width. [72] Accordingly, in the first catalyst plate 58, the gas ascending from the lower portion can ascend through the holes 62. [73] As in the above description, since the wastewater or gas contacts the first catalyst plate 35, the biochemical treatment can be processed. Therefore, the reaction speed is increased. [74] That is, it is possible to improve the ozone concentration. And since the contacting area between the ozone and wastewater is increased by improving the ozone concentration, the reaction speed may also be increased. [75] As shown in FIGS. 1 and 2, an exhaust tube 20 is connected to the residing space S of the reaction tank 10. Therefore, if the gas such as ozone is collected at the residing space S to a predetermined amount, the gas can be exhausted out of the reaction tank

10 through the exhaust tube 20. [76] At this point, since the pressure around the outlet is atmospheric pressure, the gas is exhausted quickly and a in a large amount. Therefore, the wastewater stored in the upper space is sucked into the pipe and exhausted to the lower space, thereby cleaning the second catalyst layer 46. [77] Also, a circulation means 18 is mounted on a side of the reaction tank 10 for circulating the wastewater stored in the upper space of the reaction tank 10 in a vertical direction.

[78] The circulation means includes an upper pipe 25 connected to the upper portion of the reaction tank 10, a lower pipe 19 connected to the lower portion of the reaction tank 10, and a pump Pl for pumping the wastewater.

[79] Accordingly, when the pump Pl is driven, the wastewater stored in the upper space of the reaction tank 10 is sucked into the upper and lower pipes 25 and 19 and exhausted to the lower space, thereby circulating the wastewater in the reaction tank 10.

[80] A manhole 52 is provided at an outer portion of the reaction tank 10. The manhole

52 is arranged at a position that corresponds with each gas separation unit 12 so as to wash the inner side of the reaction tank 10 or to manage.

[81] The reaction tank 10 is a PFR type in which the fluids move upward continuously.

Therefore, since the reaction proceeds under the condition of a lowering concentration of organic matter and gas, and microorganisms, as it goes upward, it is possible for the reaction time to be reduced.

[82] In the above description, although the lower part of the reaction tank 10 has a hopper shape, the present invention is not limited to this case. For example, the lower portion of the reaction tank 10 may be formed in a flat shape.

[83] That is, as shown in FIG. 7, the lower portion 70 of the reaction tank 10 has a flat shape. Since the rest of the reaction tank 10 has an identical shape with the above reaction tank, a detailed explanation will be omitted. The operation of the wastewater treatment apparatus according to an embodiment of the present invention will be described in more detail hereinafter. As shown in FIGS. 1 through 3, wastewater to be treated is introduced into the reaction tank 10 through the wastewater supply tube 22, and the gas such as ozone is also introduced into the reaction tank 10 through the gas supply tube 24. As described above, the wastewater is introduced into the reaction tank 10 to be treated. The wastewater ascends to pass through the first and second gas separation parts 32 and 34 so as to reach the upper portion of the reaction tank 10. In addition, the gas introduced through the gas supply tube 24 ascends while passing through the wastewater and the first catalyst plate 35 so as to reach the first gas separation unit 32. As the gas is collected, the gas presses the wastewater in a lower direction so as to define the residing spaces S. At this point, the gas passing the holes 48 of the first catalyst plate 35 contacts the second catalyst layer 46. Accordingly, since the gas contacts the second catalyst layer 46, it is possible to maximize the ozone concentration by an oxidizing reaction, and to generate the free radicals (OH), thereby increasing the reaction speed with contamination materials. As the gas is collected at a lower surface of the first gas separation unit 32, the level of the wastewater becomes identical to a lowest portion of the fluid flowing tubes 38. When the level of the wastewater goes below the lowest portion of the fluid flowing tube 38, the gas collected in the residing spaces S is introduced into the fluid flowing tubes 38. In this process, the gas in the residing spaces S contacts the first catalyst layer 42 so as to generate the oxidizing reaction which is identical to that in the second catalyst layer

46. [84] It is very short distance between the wastewater level W defined in the residing spaces S and the catalyst plate 35. Therefore, the gas ascending from the lower portion passes through the thin fluid layer at a relatively fast speed, and is sucked into the fluid flowing tube 38. [85] In this process, since the gas and wastewater can contact each other under the condition of forming a thin water depth and a continuous flow, it can induce high contact effects, high reaction speed, and high dissolved speed of the ozone. [86] At this point, the gas collected in the residing spaces S is in a state such that the gas and ozone are intermingled with each other. The ozone then falls downward by a difference of molecular weight, thereby incurring the concentration difference. [87] Therefore, since the high concentration of ozone contacts with the water surface, the free radicals are generated to maximize the ozone concentration at the water surface, thereby increasing the reaction speed between wastewater and contamination materials. [88] Also, in this process, since the wastewater stored at the upper portion of the reaction tank 10 drops downward to fill the residing spaces S when the gas is exhausted, the fluidity may be increased. [89] In the above description, the gas passing through the first gas separation part 32 reaches the second gas separation part 34. [90] In the course of passing through the second gas separation part 34, the gas goes through the biochemical process which is identical to that of the first gas separation part 32. [91] That is, the ascending wastewater contacts the second catalyst plate 37 that is provided at the lower portion of the second gas separation part 34 so as to be treated by the biochemical reaction. [92] And, in the course of ascending through the second gas separation part 34, the gas is contacted with the catalyst layer, and the additional oxidizing reaction is processed so as to treat the wastewater. [93] As described above, the gas passing through the first and second gas separation parts 32 and 34 reaches the uppermost space of the reaction tank 10, and is exhausted to the external side through the gas exhaust tube 14 and the wastewater exhaust tube

15. [94] The inventive wastewater treatment plant can reduce soluble micro products that are generated in the long-term process, and can reduce the generation amount of the sludge.

Industrial Applicability

[95] The present invention relates to a wastewater treatment plant, and more particularly, to a wastewater treatment plant that can improve the efficiency of wastewater treatment by providing a catalyst member capable of activating an ozone reaction in a reactor tank, thereby enhancing the reaction speed of ozone through a biochemical reaction.

Claims

[ 1 ] A wastewater treatment plant comprising: a reaction tank into which wastewater and a gas are introduced; more than one gas separation unit dividing an internal space of the reaction tank into upper and lower sections to define a residing space by ascending gas so as to increase a residing time of gas and an amount of dissolved oxygen by increasing a contact area of the wastewater and gas, to incur a concentration difference by a difference of molecular weight of gas, and to increase the concentration of gas caused by a catalyst reaction, thereby activating an oxidizing reaction; and a means for biochemical treatment provided at a lower portion of the gas separation unit, and for forming a catalyst layer to activate the ozone reaction so as to generate a biochemical reaction while the ozone is in contact with wastewater.

[2] The wastewater treatment plant of claim 1, wherein the reaction tank comprises a wastewater supply tube that introduces the wastewater, a gas supply tube through which the gas is introduced, a gas exhaust tube for exhausting the gas out of the reaction tank, a treated water exhaust tube for exhausting the wastewater that is treated by the reaction tank, and an exhaust tube that is connected to the space of the reaction tank, and to exhaust the gas out of the reaction tank so as to clean the catalyst layer.

[3] The wastewater treatment plant of claim 1, wherein the gas separation unit comprises first and second gas separation parts, each of the first and second gas separation parts comprising at least one plate dividing an inner space of the reaction tank into upper and lower sections and provided with a plurality of through holes, a plurality of fluid flowing tubes formed on a bottom of the plate to define the residing space for collecting the gas and to allow the wastewater and the gas to flow therealong so as to increase the amount of dissolved oxygen, and a first catalyst layer provided at the lower portion of the fluid flowing tubes and for generating an oxidizing reaction while being contacted with gas, wherein the gas collected in the residing spaces forms a thin fluid layer, and the wastewater moves the thin fluid layer, thereby increasing the reaction speed of the wastewater.

[4] The wastewater treatment plant of claim 3, wherein the means for biochemical treatment comprises a first catalyst plate arranged at a lower portion of the first gas separation unit and formed with a plurality of holes therein, a second catalyst plate arranged at a lower portion of the second gas separation unit, a second catalyst layer formed at the outer surface of the first and second catalyst plate, and a connecting bar for connecting the first and second catalyst plates to the inner side of the reaction tank.

[5] The wastewater treatment plant of any one of claims 3 and 4, wherein the second catalyst layer includes oxidizing titanium.

[6] The wastewater treatment plant of claim 3, wherein the first and second gas separation units are provided with a UV lamp at the lower portion thereof.

[7] The wastewater treatment plant of claim 4, wherein the first and second catalyst plates are circular.

[8] The wastewater treatment plant of claim 4, wherein the first and second catalyst plates comprise a body having a concave shape and formed with a plurality of holes, and an edge portion formed at an upper edge of the body with a predetermined width.

[9] The wastewater treatment plant of claim 1, wherein the reaction tank further includes a circulation means comprising an upper pipe connected to the upper portion of the reaction tank, a lower pipe connected to the lower portion of the reaction tank, and a pump for pumping the wastewater.

[10] The wastewater treatment plant of claim 1, wherein the gas includes any one of ozone, nitrogen, and air.