Final wastewater treatment device for high-concentration persistent organic matter, system using said device, and final wastewater treatment method for high-concentration persistent organic matter

Abstract

To provide a waste water final treatment apparatus for highly concentrated persistent organic matter using ozone microbubbles and / or ozone nanobubbles, and a system and a method using the apparatus.SOLUTION: A wastewater final treatment apparatus 1 for highly concentrated persistent organic matter includes an ozone generator 2, an ozone decomposition reactor 3, an ozone-ultraviolet decomposition reactor 4, and an ozone catalytic reactor 5, in which the ozone decomposition reactor comprises an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower 35, a first circulation pump, and a first activated carbon tower 37. The ozone-ultraviolet decomposition reactor has an ozone-ultraviolet decomposition reaction tank, a UV irradiator, a second microbubble generator, a second crushing tower 45, a third circulation pump, and a second activated carbon tower 47 there inside. The ozone catalytic reactor has an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower 54, a fifth circulation pump, and a third activated carbon tower 56.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a final treatment device for wastewater containing high concentrations of persistent organic matter, which uses water containing ozone gas-containing microbubbles (hereinafter referred to as "ozone microbubbles") and / or ozone gas-containing nanobubbles (hereinafter referred to as "ozone nanobubbles"), a system using the device, and a final treatment method for wastewater containing high concentrations of persistent organic matter. [Background technology]

[0002] Ozone has a strong oxidizing power second only to fluorine, and is generally known to be used for sterilization, virus inactivation, deodorization, decolorization, removal of organic matter, etc. in fields such as medicine, food, agriculture, livestock, and cleaning of semiconductor products. Furthermore, ozone is known to be used not only in the aforementioned fields but also in wastewater treatment fields such as industry, agriculture, and daily life.

[0003] In the field of wastewater treatment, the advantage of using ozone is that it can oxidize not only metals but also organic matter, as mentioned above. For example, a method and system for treating wastewater containing organic matter, which utilizes this property, is disclosed in Japanese Patent No. 3468414 (Patent Document 1).

[0004] The method and system described in Patent Document 1 treats wastewater containing organic matter and persistent substances with ozone in a two-stage negative pressure separation tank, and after ozone treatment, further treats the wastewater by microbial aeration and sedimentation separation. When treating the wastewater with ozone in the negative pressure separation tank, i.e., when condensing and mixing the wastewater with ozone, a vortex is used to efficiently treat the wastewater with ozone.

[0005] However, with the method and system described in Patent Document 1, ozone treatment of wastewater is sufficient to sterilize the wastewater, but it only changes persistent substances from persistent to easily degradable substances, and ultimately depends on microbial aeration and sedimentation separation. Furthermore, it is unclear whether wastewater with high BOD (biochemical oxygen demand) and COD (chemical oxygen demand) values, i.e., wastewater containing high concentrations of organic matter, can be treated.

[0006] Here, when treating wastewater using ozone, methods for treating organic matter in wastewater by converting ozone gas into tiny bubbles (microbubbles) on the order of tens to hundreds of micrometers and / or bubbles (nanobubbles) on the order of tens to hundreds of nanometers are disclosed in, for example, Japanese Patent Laid-Open Publication Nos. 2012-106211 (Patent Document 2), 2012-106212 (Patent Document 3), and 2012-106213 (Patent Document 4). The method described in Patent Document 2 is a wastewater pretreatment method that removes high-molecular-weight (molecular weight of 10,000 or more) organic fine solid matter, thereby enabling efficient subsequent wastewater treatment. The method described in Patent Document 3 involves decomposing organic matter in wastewater using ozone microbubbles and free radicals generated by the forced collapse of the ozone microbubbles, and then further treating the wastewater with an inorganic coagulant to precipitate a detoxified precipitate. The method described in Patent Document 4 treats the final remaining organic matter, i.e., organic fine solid matter, that cannot be treated by the method described in Patent Document 3, by passing it through activated carbon together with ozone microbubbles and / or ozone nanobubbles.The methods described in Patent Documents 2 to 4 are effective for wastewater with a relatively high concentration of COD value of 1000 mg / L or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3468414 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-106211 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-106212 [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-106213 [Patent Document 5] Patent No. 6635444 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as mentioned above, the method and system described in Patent Document 1 merely converts persistent substances from difficult to easily decomposable to easily decomposable, and ultimately depends on microbial aeration and sedimentation separation. Furthermore, it is unclear whether the method and system can decompose persistent substances, such as acrylic wastewater, glass wastewater, and wastewater containing polar solvents such as aldehydes and THF, and furthermore, it is unclear whether wastewater containing high concentrations of persistent substances can be treated.

[0009] Furthermore, in Patent Document 2, organic matter is not completely treated, considering that it is merely a pretreatment method for wastewater treatment. Furthermore, since the method of Patent Document 2 uses foam separation, it is sufficient if foam can be generated efficiently, but it is possible that foam generation is not confirmed or organic matter does not move into the foam.

[0010] Furthermore, concerns remain regarding Patent Document 3, such as the difficulty of treating organic matter in wastewater without first removing suspended solids, and the fact that COD cannot be reduced without relying on coagulants in addition to ozone microbubbles and / or ozone nanobubbles. Patent Document 4 focuses solely on high-molecular-weight (10,000 or greater) organic fine solids, making it unclear whether it can decompose the aforementioned difficult-to-decompose substances such as acrylics and glass. Furthermore, the backwash process for activated carbon used as a catalyst is performed with water (excluding water containing microbubbles and / or nanobubbles), potentially shortening the lifespan of the activated carbon. Even if it were possible to react organic matter other than organic fine solids with ozone under an activated carbon catalyst, the COD value must be kept low (40–100 mg / L), otherwise adsorption would take precedence and the catalytic reaction would likely not occur.

[0011] Furthermore, Patent Documents 2 to 4 state that all organic substances can be treated. However, when the technologies described in these documents are combined, even if it is possible to remove organic fine solid substances, it is unclear whether it is possible to treat persistent substances such as acrylic wastewater, glass wastewater, and wastewater containing polar solvents such as aldehydes and THF, as well as nitrogen fixatives such as ammonium sulfate and ammoniacal, nitrite, or nitrate nitrogen.

[0012] Therefore, for example, Japanese Patent No. 6635444 (Patent Document 5) discloses a final wastewater treatment device for high-concentration persistent organic matter that uses ozone microbubbles and / or ozone nanobubbles, a system using the device, and a final wastewater treatment method for high-concentration persistent organic matter, which enables the treatment of persistent organic matter and even nitrogen fixatives such as ammonium sulfate and ammoniacal, nitrite, or nitrate nitrogen, and does not require running costs.

[0013] The device and system described in Patent Document 5 are broadly composed of an ozone decomposition reactor and an ozone catalytic reactor, and the final wastewater treatment method using these devices utilizes ozone microbubbles and / or ozone nanobubbles to treat most of the organic matter by reacting the organic matter with ozone in the ozone decomposition reactor, and also uses a layered activated carbon layer as a catalytic reaction field to treat persistent organic matter and organic fine solid substances by reacting the final residues and suspended matter that could not be treated in the ozone decomposition reactor or activated carbon tower with ozone in the ozone catalytic reactor.

[0014] However, in the device and system described in Patent Document 5, there are concerns that free radicals or ozone gas generated by the collapse of ozone microbubbles and / or ozone nanobubbles, which are important factors in wastewater treatment, tend to return to oxygen through an equilibrium reaction, resulting in the generation of dissolved oxygen. In addition, if the activated carbon layer becomes contaminated, a backwash (cleaning) process must be performed frequently, resulting in high running costs for maintaining the activated carbon layer.

[0015] In view of the above circumstances, the present invention provides a final treatment device for wastewater containing high concentrations of persistent organic matter, which uses ozone microbubbles and / or ozone nanobubbles, and which enables the treatment of persistent organic matter and, further, nitrogen fixatives such as ammonium sulfate and ammoniacal, nitrite, or nitrate nitrogen, as well as the treatment of organic fine solid substances, and which does not require running costs for maintaining the activated carbon layer; a system using the device; and a final treatment method for wastewater containing high concentrations of persistent organic matter. [Means for solving the problem]

[0016] The object of the present invention is to provide a final treatment device for wastewater containing high concentrations of persistent organic matter, comprising an ozone generator, an ozone decomposition reactor, an ozone-ultraviolet decomposition reactor, and an ozone catalytic reactor, wherein the ozone decomposition reactor comprises an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower with a punched plate installed therein, a first circulation pump, and a first activated carbon tower, and the ozone-ultraviolet decomposition reactor comprises an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second circulation pump, a second crushing tower with a punched plate installed therein, a third circulation pump, and a second activated carbon tower, and the ozone catalytic reactor The reactor comprises an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower with a punched plate installed inside, a fifth circulation pump, and a third activated carbon tower, the ozone generator being connected to the ejector pump, the first microbubble generator, the second microbubble generator, and the third microbubble generator by an ozone gas supply pipe, the ozone decomposition reaction tank, the ozone-ultraviolet decomposition reaction tank, and the ozone catalytic decomposition tank being connected by an overflow pipe, and the ozone catalytic decomposition tank being provided with a first activated carbon layer and a second activated carbon layer and a backwash water outlet, thereby effectively achieving the object of the final wastewater treatment device of the present invention. , Ozone-ultraviolet decomposition reactorand an ozone catalytic reaction device, the ozone decomposition reaction device comprises an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower with an orifice installed therein, a first circulation pump, and a first activated carbon tower, the ozone-ultraviolet decomposition reaction device comprises an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second circulation pump, a second crushing tower with an orifice installed therein, a third circulation pump, and a second activated carbon tower, the ozone catalytic reaction device comprises an ozone catalytic decomposition tank, a third microbubble generator, an ejector pump, a first crushing tower with an orifice installed therein, a third circulation pump, and a second activated carbon tower, the ozone catalytic reaction device comprises an ozone catalytic decomposition tank, a third microbubble generator, an ejector pump, a first crushing tower with an orifice installed therein, a first circulation pump, and a first activated carbon tower, the ozone-ultraviolet decomposition reaction device comprises an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second circulation pump, a second ... the ozone generator is connected to the ejector pump, the first microbubble generator, the second microbubble generator, and the third microbubble generator by an ozone gas supply pipe; the ozone decomposition reaction tank, the ozone-ultraviolet decomposition reaction tank, and the ozone catalytic decomposition tank are connected by an overflow pipe; and the ozone catalytic decomposition tank is provided with a first activated carbon layer and a second activated carbon layer and a backwash water outlet.

[0017] The wastewater final treatment apparatus according to the present invention is also configured such that the first crushing tower is installed to circulate raw wastewater containing ozone microbubbles between the first crushing tower and the ozone decomposition reaction tank through a plurality of pipes, or the first activated carbon tower is installed to circulate raw wastewater containing ozone gas, ozone microbubbles and / or ozone nanobubbles between the first crushing tower and the ozone decomposition reaction tank through a plurality of pipes, or the second crushing tower is installed to circulate raw wastewater containing ozone microbubbles between the second crushing tower and the ozone-ultraviolet decomposition reaction tank through a plurality of pipes, or the second activated carbon tower is installed to circulate raw wastewater containing ozone gas, ozone microbubbles and / or ozone nanobubbles between the first crushing tower and the ozone-ultraviolet decomposition reaction tank through a plurality of pipes. the third activated carbon tower is installed so as to circulate raw wastewater containing ozone gas, ozone microbubbles, and / or ozone nanobubbles between the ozone catalytic decomposition tank and the activated carbon tower; the third activated carbon tower is installed so as to circulate raw wastewater containing ozone gas, ozone microbubbles, and / or ozone nanobubbles between the ozone catalytic decomposition tank and the activated carbon tower; the activated carbon packed in the first activated carbon tower, the second activated carbon tower, and the third activated carbon tower is granular activated carbon, and the diameter of the activated carbon is 1 to 2 mm; or the activated carbon packed in the first activated carbon tower is pellet-type activated carbon with a diameter of 6 to 7 mm; 2 This can be achieved more effectively by using pellet-type activated carbon having a diameter of 3 to 4 mm as the activated carbon packed in the activated carbon layer, or by further providing another ozone decomposition reactor and a coagulation and sedimentation tank.

[0018] The object of the wastewater final treatment system according to the present invention is to provide a wastewater final treatment system for high-concentration persistent organic matter using the above-mentioned device, the wastewater final treatment system including: an ozone decomposition treatment system that treats raw wastewater using an ozone decomposition reaction device comprising an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower with a punched plate installed inside, a first circulation pump, and a first activated carbon tower; and an ozone-ultraviolet decomposition reaction system that treats the raw wastewater treated by the ozone decomposition treatment system using an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second crushing tower with a punched plate installed inside, a third circulation pump, and a second activated carbon tower. The present invention is effectively achieved by providing an ozone catalytic decomposition system in which the raw wastewater treated by the ozone decomposition treatment system and the ozone-ultraviolet decomposition treatment system is treated by an ozone catalytic reaction device comprising an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower with a punching plate installed inside, a fifth circulation pump, and a third activated carbon tower, and having a first activated carbon layer and a second activated carbon layer installed inside, and wherein the raw wastewater is irradiated with ultraviolet rays for 2 to 12 hours in the ozone-ultraviolet decomposition treatment system, and the raw wastewater is passed through the first activated carbon layer and the second activated carbon layer at a flow rate of 10 to 100 cm / sec in the catalytic decomposition system.Another object of the wastewater final treatment system according to the present invention is a wastewater final treatment system for high-concentration persistent organic matter using the above-mentioned device, which includes an ozone decomposition treatment system that treats raw wastewater using an ozone decomposition reaction device comprising an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first collapsing tower with an orifice installed inside, a first circulation pump, and a first activated carbon tower, and an ozone-ultraviolet decomposition treatment system that treats the raw wastewater treated by the ozone decomposition treatment system using an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second collapsing tower with an orifice installed inside, a third circulation pump, and a second activated carbon tower. and an ozone catalytic decomposition system in which the raw wastewater treated by the ozone decomposition treatment system and the ozone-ultraviolet decomposition treatment system is treated by an ozone catalytic reaction device comprising an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower with an orifice installed therein, a fifth circulation pump, and a third activated carbon tower, and having a first activated carbon layer and a second activated carbon layer installed therein; wherein the ozone-ultraviolet decomposition treatment system irradiates the raw wastewater with ultraviolet rays for 2 to 12 hours; and the catalytic decomposition system passes the raw wastewater through the first activated carbon layer and the second activated carbon layer at a flow rate of 10 to 100 cm / sec.

[0019] Furthermore, the object of the wastewater final treatment system according to the present invention can be more effectively achieved by further comprising at least one of the ozone decomposition treatment system, the coagulation treatment system, the filtration treatment system, and / or at least the ozone catalytic decomposition system, or by the activated carbon packed in the first activated carbon layer being pellet-type activated carbon with a diameter of 6 to 7 mm, and the activated carbon packed in the second activated carbon layer being pellet-type activated carbon with a diameter of 3 to 4 mm.

[0020] Furthermore, the object of the method for final wastewater treatment according to the present invention can be effectively achieved by a method for final wastewater treatment using the above-mentioned final wastewater treatment system, comprising an ozone decomposition treatment step, an ozone-ultraviolet decomposition treatment step, and an ozone catalytic decomposition treatment step, wherein the raw wastewater is irradiated with ultraviolet light for 2 to 12 hours in the ozone-ultraviolet decomposition treatment step.

[0021] Furthermore, the object of the final wastewater treatment method according to the present invention can be more effectively achieved by including at least one of the ozone decomposition treatment step, the coagulation treatment step, the filtration treatment step, and / or the ozone catalytic decomposition step. [Effects of the Invention]

[0022] The wastewater final treatment device according to the present invention enables the treatment of persistent organic matter or nitrogen fixatives such as ammonium sulfate and ammoniacal, nitrite, or nitrate nitrogen, as well as polar solvents including 1,4-dioxane, and the like, and also enables the treatment of wastewater final treatment devices for high concentrations of persistent organic matter using ozone microbubbles and / or ozone nanobubbles, with low running costs.

[0023] Furthermore, the wastewater final treatment system and method using the wastewater final treatment device for high-concentration persistent organic matter according to the present invention include a decomposition reaction treatment using ozone microbubbles and / or nanobubbles and ozone gas, an ultraviolet irradiation treatment, and a catalytic reaction treatment in which free radicals generated by the collapse of ozone microbubbles and / or nanobubbles and ozone microbubbles react with persistent organic matter such as acrylics and organic fine solid substances in the presence of an activated carbon catalyst, and an ultraviolet irradiation treatment, thereby making it possible to treat wastewater with a COD of 5,000 (up to 500,000) mg / L or more. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram showing a final treatment device for wastewater containing high concentrations of persistent organic matter according to the present invention. [Figure 2]1 is a schematic diagram showing another embodiment of a final treatment device for wastewater containing high concentrations of persistent organic matter according to the present invention. [Figure 3] 1 is a system schematic diagram showing one embodiment of a wastewater final treatment system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] First, the final treatment apparatus for wastewater containing high concentrations of persistent organic matter according to the present invention will be described in detail with reference to the drawings.

[0026] FIG. 1 is a schematic diagram showing a final wastewater treatment apparatus for high-concentration persistent organic matter according to the present invention. As shown in FIG. 1, the final wastewater treatment apparatus 1 comprises an ozone generator 2, an ozone decomposition reactor 3, an ozone-ultraviolet decomposition reactor 4, and an ozone catalytic reactor 5. The ozone decomposition reactor 3 comprises an ozone decomposition reaction tank 31, a raw water inlet 32, a first microbubble generator 33, an ejector pump 34, a first crushing tower 35, a first circulation pump 36, and a first activated carbon tower 37. The ozone-ultraviolet decomposition reaction apparatus 4 comprises an ozone-ultraviolet decomposition reaction tank 41, an ultraviolet irradiator 42, a second microbubble generator 43, a second circulation pump 44, a second crushing tower 45, a third circulation pump 46, and a second activated carbon tower 47. The ozone catalytic reaction device 5 includes an ozone catalytic decomposition tank 51, a third microbubble generator 52, a fourth circulation pump 53, a third crushing tower 54, a fifth circulation pump 55, and a third activated carbon tower 56. A first activated carbon layer 57 and a second activated carbon layer 58 are disposed inside the ozone catalytic decomposition tank 51, and a backwash water outlet 59 is provided. Ozone gas is supplied from the ozone gas generator 2 through an ozone gas supply pipe Ts connected to the ejector pump 34, the first microbubble generator 33, the second microbubble generator 43, and the third microbubble generator 52. The supply rate of ozone gas is 150 to 600 g / h. If the supply rate of ozone gas is less than 150 g / h, the raw wastewater is hardly treated, and even if the supply rate is more than 600 g / h, the treatment capacity does not change significantly.

[0027] Next, the ozone reaction device 3 will be described in more detail. In the embodiment shown in FIG. 1, the raw water inlet 32 ​​is provided in a columnar shape at the top of the ozone decomposition reaction tank 31, but the shape is not particularly limited. Furthermore, since the inlet 32 ​​is only required to inject wastewater containing a high concentration of persistent organic matter (hereinafter referred to as "raw water") into the ozone decomposition reaction tank 31, the top of the ozone decomposition reaction tank 31 may be an open system and no separate inlet is required. Next, in the embodiment shown in FIG. 1, the first microbubble generator 33 is provided at the top of the ozone decomposition reaction tank 31. However, since it is sufficient that microbubbles are evenly distributed from the outlet to the raw water, the installation location may be slightly offset from the center of the ozone decomposition reaction tank 31. The shape and type of the first microbubble generator 33 are not particularly limited as long as they are capable of introducing (supplying) ozone gas from the ozone generator 2. The ozone microbubbles (diameter: about 20 to 200 μm) supplied from the first microbubble generator 33 turn the raw water into a gas-liquid mixture containing ozone microbubbles (hereinafter referred to as "ozone microbubble-containing raw water").

[0028] As shown in FIG. 1, the first crushing tower 35 is installed so that the ozone microbubble-containing raw water described above is circulated through pipes Ta, Tb, and Tc in the order of pipe Ta, Tb, and Tc (see arrows). In this case, the pipes Ta, Tb, and Tc may be made of any material, such as metal or plastic, as long as they can circulate the microbubble-containing raw water. Furthermore, the pipes may be designed for laminar or turbulent flow. Here, an ejector pump 34 is required to circulate the ozone microbubble-containing raw water between the first crushing tower 35 and the ozonolysis reaction tank 31. This configuration is used not only for circulating the ozone microbubble-containing raw water described above, but also for introducing ozone gas directly from the ozone gas generator 2 into the raw water (hereinafter, this raw water will be referred to as "ozone gas-introducing raw water" to distinguish it from the ozone microbubble-containing raw water). The purpose of passing ozone microbubble-containing raw water and ozone gas-infused raw water through the first crushing tower 35 is to crush the ozone microbubbles contained in the raw water to produce ozone nanobubbles (100 to 500 nm order) in the case of ozone microbubble-containing raw water, or to generate a gas-liquid (ozone-raw water) mixture and circulate it to further transform the gas-liquid mixture into ozone microbubble-containing raw water. In other words, the purpose is to continuously generate ozone microbubbles and ozone nanobubbles. Although not shown, punched plates and orifices (perforated plates) for crushing microbubbles are inserted into the crushing tower. The hole diameter and shape of the punched plates and orifices are not particularly limited in the systems and methods described below, as long as they can crush the microbubbles.

[0029] Next, as shown in FIG. 1 , the first activated carbon tower 37, like the first crushing tower 35, is installed so that the gas-liquid mixture raw water containing the aforementioned ozone gas (ozone microbubbles and / or ozone nanobubbles) is circulated through pipes Td, Te, and Tf in this order (see arrows). In this case, the pipes Td, Te, and Tf may be made of any material, such as metal or plastic, as long as they can circulate the raw water. Furthermore, the pipes may also be designed for laminar or turbulent flow. Here, a first circulation pump 36 is required to circulate the microbubble-containing raw water between the first activated carbon tower 37 and the ozone decomposition reaction tank 31. There are no particular limitations on the type of the first circulation pump 36, as long as it is capable of circulating wastewater (e.g., raw water) between the activated carbon tower 37 and the ozone decomposition reaction tank 31 at a circulation rate of 100 to 200 L / min. The circulation rate by the ejector pump 34 when circulating the above-mentioned microbubble-containing raw water between the first crushing tower 35 and the ozone decomposition reaction tank 31 is also 100 to 200 L / min. The reasons and effects of adopting a circulation rate of 100 to 200 L / min will be described later.

[0030] The purpose of the first activated carbon tower 37 is to remove compounds resulting from the reaction between organic matter in the raw water and ozone, as well as to remove microorganisms and the like in the raw water. The activated carbon packed into the tower is preferably granular activated carbon with a diameter of 1 to 2 mm. If the diameter of the activated carbon is less than 1 mm, it will not be able to remove these compounds or microorganisms, while if the diameter of the activated carbon is greater than 2 mm, the raw water may not circulate and the tower may become clogged. It is sufficient to pack the activated carbon so that it fills 70 to 80 percent of the volume of the first activated carbon tower 37.

[0031] By pretreating the raw water in the ozone reaction device 3 configured as above, most of the organic matter is treated, and the COD and TOC values ​​are reduced to about 1 / 2 to 1 / 5 of those of the raw water.

[0032] Next, the ozone-ultraviolet decomposition reaction apparatus 4 will be described in more detail. First, in the embodiment shown in FIG. 1, the overflow pipe To is shown as connecting (coupling) the top of the ozone decomposition reaction tank 31 and the top of the ozone-ultraviolet decomposition reaction tank 41. However, as long as raw water pretreated in the ozone decomposition reaction apparatus 3 (hereinafter referred to as "pretreated raw water") can be introduced into the ozone-ultraviolet decomposition reaction tank 41, there are no particular limitations on the piping method or installation location. Next, in the embodiment shown in FIG. 1, the second microbubble generator 43 is provided above the ozone-ultraviolet decomposition reaction tank 41. However, as long as microbubbles are evenly distributed from the outlet throughout the pretreated raw water, the installation location may be slightly offset from the center of the ozone-ultraviolet decomposition reaction tank 41. Note that the shape and type of the second microbubble generator 43 are not particularly limited as long as it can introduce (supply) ozone gas from the ozone generator 2. The pretreated raw water becomes a gas-liquid mixture containing ozone microbubbles due to the ozone microbubbles (diameter: about 20 to 200 μm) supplied from the second microbubble generator 43. The second microbubble generator 43 may be the same as the first microbubble generator 33.

[0033] In the embodiment shown in FIG. 1 , the ultraviolet irradiator 42 is installed above the ozone-ultraviolet decomposition reactor 41. However, since the ultraviolet irradiator 42 only needs to irradiate the pretreated raw water in the ozone-ultraviolet decomposition reactor 41, it may be installed in the middle or bottom of the reactor 41, rather than above, or may be externally irradiated. The purpose of the ultraviolet irradiator 42 is to minimize the conversion of ozone to oxygen molecules when some of the ozone microbubbles in the raw water remain uncollapsed. In other words, the ultraviolet irradiator 42 is intended to generate active oxygen species and hydroxyl radicals from ozone by irradiating the raw water with ultraviolet light. Another purpose of the ultraviolet irradiator 42 is to promote the reaction of suspended matter and organic fine solid matter with ultraviolet light when the activated carbon layer, described below, is no longer functioning as a catalytic reaction site or when its function needs to be deactivated. Reactive oxygen species are known to function similarly to free radicals generated when ozone microbubbles and / or ozone nanobubbles are forcibly collapsed. They oxidize substances other than ozone and oxygen, thereby treating organic matter. The wavelength of UV light used for treating organic matter is not particularly limited as long as it is in the UV range (approximately 100 to 380 nm). It is best to irradiate the raw water with UV light while it is being treated. The preferred irradiation time is 2 to 12 hours. If the irradiation time is less than 2 hours, the COD and TOC values ​​will be similar to or not significantly different from those of the raw water, and treatment for 12 hours or longer will not significantly improve efficiency. The pH of the raw wastewater or pretreated raw water is preferably in the neutral range of approximately 6.5 to 7.9. While UV decomposition reactions are possible in the weakly basic range of pH 8 to 9 or the weakly acidic range of pH around 5, the efficiency is lower than when the water is neutral. This is due to the reactivity of ozone gas and hydroxyl radicals.

[0034] Next, as shown in FIG. 1 , the second collapse tower 45 is installed so that the microbubble-containing pretreated raw water described above is circulated through pipes Ta′, Tb′, and Tc′ in this order (see arrows). In this case, the pipes can be made of any material, such as metal or plastic, as long as they can circulate the microbubble-containing pretreated raw water. Furthermore, the pipes can be used for laminar or turbulent flow. Here, a second circulation pump 44 is required to circulate the microbubble-containing raw water between the second collapse tower 45 and the ozone-ultraviolet decomposition reaction tank 41. The purpose of passing the microbubble-containing pretreated raw water through the second collapse tower 45 is to crush the ozone microbubbles contained in the raw water and turn them into ozone nanobubbles (on the order of 100 to 500 nm). In other words, the purpose is to continuously generate ozone microbubbles and ozone nanobubbles. Although not shown, punching plates and orifices (perforated plates) for crushing microbubbles are inserted into the second crushing tower 45, similar to the first crushing tower 35. Incidentally, there are no particular limitations on the hole diameter and shape of the punching plates and orifices, etc., as long as they can crush microbubbles, when used in the method described below.

[0035] Next, as shown in FIG. 1, the second activated carbon tower 47, like the second crushing tower 45, is installed so that the previously described ozone microbubble-containing pretreated raw water is circulated through pipes Td′, Te′, and Tf′ in this order (see arrows). In this case, the pipes can be made of any material, such as metal or plastic, as long as they can circulate the pretreated raw water containing ozone microbubbles (and / or ozone nanobubbles). Furthermore, the pipes can be designed to have laminar or turbulent flow. Here, a third circulation pump 46 is required to circulate the pretreated raw water containing ozone microbubbles (and / or ozone nanobubbles) between the second activated carbon tower 47 and the ozone-ultraviolet decomposition reaction tank 41. There are no particular limitations on the type of third circulation pump 46, as long as it is a pump that can circulate wastewater (raw water, etc.) between the second activated carbon tower 47 and the ozone-ultraviolet decomposition reaction tank 41 at a circulation rate of 100 to 200 L / min. The circulation rate by the third circulation pump 46 when circulating the microbubble-containing raw water described above between the second crushing tower 45 and the ozone-ultraviolet decomposition reaction tank 41 is also 100 to 200 L / min. The reasons and effects of adopting a circulation rate of 100 to 200 L / min will be described later.

[0036] The second activated carbon tower 47, like the first activated carbon tower 37, has the purpose of removing compounds resulting from the reaction between organic matter in the raw water and ozone, as well as removing microorganisms and the like in the raw water. Granular activated carbon with a diameter of 1 to 2 mm is desirable as the activated carbon packed inside the tower. If the diameter of the activated carbon is less than 1 mm, it will not be able to remove these compounds or microorganisms, while if the diameter of the activated carbon is greater than 2 mm, the raw water may not circulate and the tower may become clogged. As with the first activated carbon tower 37, the activated carbon need only be packed to fill 70 to 80 percent of the volume of the second activated carbon tower 47.

[0037] Next, the ozone catalytic reaction apparatus 5 will be described in more detail. First, in the embodiment shown in FIG. 1, the overflow pipe To′ is shown as connecting (coupling) the upper part of the ozone-ultraviolet decomposition reaction tank 41 and the upper part of the ozone catalytic decomposition tank 51. However, the essential point is that it is sufficient to introduce raw water secondarily pretreated in the ozone-ultraviolet decomposition reaction apparatus 4 (hereinafter referred to as "secondary pretreated raw water") into the ozone catalytic decomposition tank 51, so there are no particular limitations on the piping method or installation location. Next, in the embodiment shown in FIG. 1, the third microbubble generator 52 is provided above the ozone catalytic decomposition tank 51. However, as long as microbubbles are evenly distributed from the outlet throughout the pretreated raw water, the installation location may be slightly offset from the center of the ozone catalytic decomposition tank 51. Note that the shape and type of the third microbubble generator 52 are not particularly limited as long as it is capable of introducing (supplying) ozone gas from the ozone generator 2. The secondary pretreated raw water becomes a gas-liquid mixture containing ozone microbubbles due to the ozone microbubbles (diameter: about 20 to 200 μm) supplied from the third microbubble generator 52. The third microbubble generator 52 may be the same as the first microbubble generator 33 or the second microbubble generator 43.

[0038] Next, as shown in FIG. 1 , the third collapse tower 54 is installed so that the microbubble-containing secondary pretreated raw water described above is circulated through pipes Ta″, Tb″, and Tc″ in this order (see arrows). In this case, the pipes can be made of any material, such as metal or plastic, as long as they can circulate the microbubble-containing pretreated raw water. Furthermore, the pipes can be used for laminar or turbulent flow. Here, a fourth circulation pump 53 is required when circulating the microbubble-containing raw water between the third collapse tower 54 and the ozone catalytic decomposition tank 51. The purpose of passing the microbubble-containing secondary pretreated raw water through the third collapse tower 54 is to crush the ozone microbubbles contained in the raw water and turn them into ozone nanobubbles (on the order of 100 to 500 nm). In other words, the purpose is to continuously generate ozone microbubbles and ozone nanobubbles. Although not shown, punching plates and orifices (perforated plates) for crushing microbubbles are inserted into the third crushing tower 54, similar to the first crushing tower 35 and the second crushing tower 45. Incidentally, there are no particular limitations on the hole diameter and shape of the punching plates and orifices, etc., as long as they can crush microbubbles, when used in the method described below.

[0039] Next, as shown in FIG. 1, the third activated carbon tower 56 is also installed in the same manner as the third crushing tower 54, so that the previously described ozone microbubble-containing pretreated raw water is circulated through pipes Td'', Te'', and Tf'' in this order (see arrows). In this case, the pipes may be made of any material, such as metal or plastic, as long as they can circulate the secondary pretreated raw water containing ozone microbubbles (and / or ozone nanobubbles). Furthermore, the pipes may be designed to have laminar or turbulent flow. Here, a fifth circulation pump 55 is required to circulate the secondary pretreated raw water containing ozone microbubbles (and / or ozone nanobubbles) between the third activated carbon tower 56 and the ozone catalytic decomposition tank 51. There are no particular limitations on the type of fifth circulation pump 55, as long as it is a pump that can circulate wastewater (raw water, etc.) between the third activated carbon tower 56 and the ozone catalytic decomposition tank 51 at a circulation rate of 100 to 200 L / min. The circulation rate by the fifth circulation pump 55 when circulating the microbubble-containing raw water described above between the third crushing tower 54 and the ozone catalytic decomposition tank 51 is also 100 to 200 L / min. The reasons and effects of adopting a circulation rate of 100 to 200 L / min will be described later.

[0040] The purpose of the third activated carbon tower 56, like the first activated carbon tower 37 and the second activated carbon tower 47, is to remove compounds resulting from the reaction between organic matter in the raw water and ozone, as well as to remove microorganisms from the raw water. Granular activated carbon with a diameter of 1 to 2 mm is desirable as the activated carbon packed inside the tower. If the diameter of the activated carbon is less than 1 mm, it will not be able to remove these compounds or microorganisms. If the diameter of the activated carbon is greater than 2 mm, the raw water may not circulate and the tower may become clogged. As with the first activated carbon tower 37 and the second activated carbon tower 47, the activated carbon need only fill 70 to 80 percent of the volume of the third activated carbon tower 56.

[0041] Next, the first activated carbon layer 57, the second activated carbon layer 58, and the backwash water outlet 59 in the ozone catalytic reaction device 5 will be described in order.

[0042] However, most of the organic matter and harmful microorganisms contained in raw water, pretreated raw water, and secondary raw water are treated (removed or rendered harmless) by ozone gas, ozone microbubbles and / or ozone nanobubbles, and the first activated carbon tower 37, the second activated carbon tower 47, and the third activated carbon tower 56. However, when treating wastewater containing high concentrations of persistent organic matter, as in the present invention, the removal of some of the high-molecular-weight (molecular-weight of 10,000 or more) organic fine solid substances, most of the persistent organic matter and nitrogen fixatives (e.g., ammonia and nitrite nitrogen) (hereinafter referred to as the "final residue"), and organic solvents (polar solvents including 1,4-dioxane, etc.) cannot be achieved by using only ozone gas, ozone microbubbles and / or ozone nanobubbles, and the first activated carbon tower 37, the second activated carbon tower 47, and the third activated carbon tower 56. Here, the first activated carbon layer 57 and the second activated carbon layer 58 are important components of the apparatus, system, and treatment method according to the present invention. Generally, activated carbon is known to be used as a deodorizer, adsorbent, catalyst, etc., making use of the surface area of ​​its pores. However, in conventional methods, when it is used as a catalyst, the concentration of the reaction substrate must be kept fairly low (for example, COD of about 40 to 100 mg / L in wastewater), otherwise adsorption will prevail over the catalytic reaction. Therefore, in the field of wastewater (water purification) treatment, such as in the present invention, activated carbon has mostly been used as an adsorbent.

[0043] In the device according to the present invention, the first activated carbon layer 57 and the second activated carbon layer 58 function as a reaction field, or a catalyst, between the hydroxyl radicals generated from the ozone nanobubbles, the ozone gas itself, and the final residues contained in the pre-treated raw water. Incidentally, the pre-treated raw water can be treated even if its COD is 5,000 mg / L or more (up to about 150,000 mg / L).

[0044] First, the first activated carbon layer 57 and the second activated carbon layer 58 will be described. Pellet-type activated carbon is used in the first activated carbon layer 57, and the diameter (effective diameter) of the activated carbon is 6 to 7 mm. This set range is set larger (longer) than that of the second activated carbon layer 58. On the other hand, pellet-type activated carbon is used in the second activated carbon layer 58, and the diameter (effective diameter) of the activated carbon is 3 to 4 mm. This set range is set smaller (shorter) than that of the first activated carbon layer 58. The reason for this is that if the catalytic reaction in the first activated carbon layer 57 does not proceed well, the diameter of the pellet-type activated carbon packed in the second activated carbon layer 58, which has a larger specific surface area, is set smaller than the diameter of the pellet-type activated carbon packed in the first activated carbon layer 57 so that the catalytic reaction can be reliably carried out almost quantitatively in the second activated carbon layer 58. Furthermore, if the diameter of the pellet-type activated carbon is less than 3 mm, the adsorption reaction will be more dominant than the catalytic reaction, and if it is larger than 7 mm, the pretreated raw water may not be able to pass through each layer quickly enough. Furthermore, when the pretreated raw water containing the final residue is passed through the first activated carbon layer 57 and the second activated carbon layer 58, it is desirable to pass it through each layer at a flow rate of 10 to 100 cm / sec. If the flow rate is less than 10 cm / sec, the adsorption reaction will prevail over the catalytic reaction, and if the flow rate is faster than 100 cm / sec, neither adsorption nor catalytic reaction will occur. The flow rate can be adjusted by the circulation rate of the fourth circulation pump 53 or the fifth circulation pump 55, or any flow rate adjustment means can be used.

[0045] Next, the backwash water outlet 59 will be described. The purpose of adopting this backwash water outlet 59 is to backwash the pellet-type activated carbon in the first activated carbon layer 57 and the second activated carbon layer 58 with ozone microbubble-containing water and / or ozone nanobubble-containing water. The backwashing method involves storing pre-prepared ozone microbubble-containing water and / or ozone nanobubble-containing water in an arbitrary container (not shown), and then blowing the water from the backwash water outlet 59 via the pump P to perform backwashing.

[0046] There are no particular limitations on the number of backwashing cycles or the duration of backwashing, as long as it is performed at least once every two weeks or once a month. Backwashing the pelleted activated carbon in the first activated carbon layer 57 and the second activated carbon layer 58 with ozone microbubble-containing water and / or ozone nanobubble-containing water extends the life of the pelleted activated carbon by approximately 8 to 20 times compared to backwashing with water (tap water). Batch processing is also desirable for backwashing.

[0047] An embodiment of the wastewater final treatment device for high-concentration persistent organic matter using ozone microbubbles according to the present invention has been explained above using Figure 1. Next, another embodiment of the wastewater final treatment device for high-concentration persistent organic matter using ozone microbubbles according to the present invention will be explained. Note that the same reference numerals are used for parts that overlap with Figure 1. In this explanation, explanations of parts that overlap with the embodiment shown in Figure 1 will be omitted.

[0048] Fig. 2 is a schematic diagram showing another embodiment of the final treatment system for wastewater containing high concentrations of persistent organic matter using ozone microbubbles according to the present invention. The embodiment shown in Fig. 2 is, so to speak, the system shown in Fig. 1, further equipped with another ozone decomposition reactor and a coagulation and sedimentation tank for more thorough pretreatment.

[0049] In this alternative embodiment, the wastewater treatment device 1 ′ is equipped with an ozone decomposition reactor 3 ′ and a coagulation and settling tank 50 in addition to the ozone generator 2 , the ozone decomposition reactor 3 , and the ozone catalytic reactor 4 .

[0050] The ozone decomposition reactor 3' has basically the same configuration as the ozone decomposition reactor 3, and includes an ozone decomposition reaction tank 31', a raw water inlet 32', a first microbubble generator 33', an ejector pump 34', a first crushing tower 35', a first circulation pump 36', and a first activated carbon tower 37'. The functions of the ozone decomposition reactor 3' are also basically the same as those of the ozone decomposition reactor 3, so a description thereof will be omitted.

[0051] Next, the coagulation-sedimentation tank 50 will be described. The coagulation-sedimentation tank 50 is intended to lower the COD of raw water that was not fully pretreated in the ozonolysis reactor 3' by adding a precipitating flocculant, and to treat organic fine solid matter contained in the raw water as precipitates and organic matter that was not fully pretreated in the ozonolysis reactor 3'. When coagulation-sedimentation is performed, an inorganic coagulation-sedimentation agent is added to the raw water introduced into the coagulation-sedimentation tank 50. Note that, as the inorganic coagulant, polyaluminum chloride or aluminum sulfate can be used, and a polymer coagulant can also be used as an auxiliary agent.

[0052] The sediment is separated into precipitate and supernatant (raw water) in the coagulation and sedimentation tank 50, and the supernatant raw water is introduced into the ozone decomposition reaction tank 31' of the ozone decomposition reaction device 3 through an appropriately connected inlet pipe (not shown). On the other hand, the precipitate can be compressed and dried by any method and then discarded, or the precipitate can be reused as sludge. The supernatant (raw water) is then treated in the ozone decomposition reaction device 3, the ozone-ultraviolet decomposition reaction device 4, and the ozone catalytic reaction device 5 in this order.

[0053] The final wastewater treatment device according to the present invention has been described above. However, the final wastewater treatment system according to the present invention can be realized by connecting multiple units, for example, using the final wastewater treatment device shown in Figure 1 as one unit, or by connecting any desired filtration means, or by introducing any desired process, means, or device. Furthermore, the final wastewater treatment system according to the present invention can also be realized by inserting any desired process, means, or device between the ozone decomposition reactor 3, the ozone-ultraviolet decomposition reactor 4, and the ozone catalytic reactor 5 shown in Figure 1. The final wastewater treatment system and wastewater treatment method according to the present invention will be described below with reference to the drawings. Also, Figure 1 or Figure 2 will be used as needed.

[0054] Fig. 3 is a system schematic diagram showing one embodiment of the wastewater final treatment system according to the present invention. In the embodiment shown in Fig. 3, first, raw wastewater (hereinafter simply referred to as "raw water") is diluted. Incidentally, dilution with water at a ratio of about 2 to 12 times is sufficient. If the ratio is less than 2 times, various components contained in the wastewater may deteriorate the equipment and system. Dilution at a ratio of 12 times or more does not significantly change the effect.

[0055] Next, the diluted raw water is treated in an ozone decomposition treatment system S10. In the present invention, the ozone decomposition treatment system S10 uses an ozone decomposition reactor 3 as shown in Figures 1 or 2 to perform ozone microbubble decomposition and ozone microbubble collapse treatment, i.e., ozone nanobubble decomposition treatment. As previously described in Figure 1, the raw water containing ozone microbubbles is pumped through an ejector pump and a circulation pump. The ozone microbubbles are then crushed in a crushing tower, resulting in a portion of the raw water being converted into ozone nanobubbles. This microbubble and nanobubble treatment is then performed. Furthermore, ozone gas is directly injected from the ejector pump, resulting in the raw water also becoming a gas-liquid mixture containing ozone gas. This process can be conceptualized as follows: ozone gas oxidizes and decomposes the bulk of the organic matter, and then ozone microbubbles and / or ozone nanobubbles further oxidize and decompose the finer organic matter. Ultimately, most of the organic matter is oxidized. Therefore, at the end of the ozone decomposition treatment system S10, the COD and TOC values ​​are approximately 1 / 2 to 1 / 5 of those of the raw water.

[0056] In the ozone decomposition treatment system S10, the supply rate of ozone gas is preferably 150 to 600 g / h (hour). If the supply rate of ozone gas is less than 150 g / h, the raw wastewater is hardly treated, and even if the supply rate is more than 600 g / h, the treatment capacity does not change significantly. In the ozone decomposition treatment system S10, the circulation rate of raw water in the ozone decomposition reaction device 3 is 100 to 200 L / min. If the circulation rate is less than 100 L / min, the ozone microbubbles may collapse or the ozone gas may not be introduced into the raw water properly, resulting in insufficient treatment of the raw water. Even if the circulation rate is more than 200 L / min, the treatment capacity may not improve significantly or may even decrease. In addition, the treatment in the ozone decomposition treatment system S10 is preferably performed for about 2 to 72 hours. If the treatment time is less than 2 hours, the treatment will be insufficient, and if it is more than 72 hours, the treatment will be sufficient, but it may hasten equipment failure or, depending on the organic matter, may cause an equilibrium reaction to proceed, resulting in the original substance being restored.

[0057] Next, the ozone decomposition treatment system S10 uses ozone microbubbles, ozone nanobubbles, and ozone gas to perform ozone decomposition treatment, followed by the coagulation treatment system S11. The coagulation treatment system S11 is the treatment performed in the coagulation sedimentation tank 50 in the schematic diagram shown in Figure 2. As mentioned above, the coagulation treatment performed here aims to lower the COD of raw water that has not been fully pretreated by adding a precipitating coagulant and to treat organic fine solid matter contained in the raw water as precipitate and organic matter that has not been fully pretreated. When performing coagulation sedimentation, an inorganic coagulant is added to the raw water introduced into the coagulation sedimentation tank 50. The inorganic coagulant referred to here can be aluminum- or iron-based, with aluminum sulfate (aluminum sulfate) and PAC (polyaluminum chloride) being particularly suitable. Polymeric coagulants can also be used as auxiliary agents for the inorganic coagulant. Incidentally, the coagulation treatment system S11 is not necessarily a necessary requirement, but if more efficient and complete treatment of organic fine solid matter is desired, it is advisable to install the coagulation treatment system S11. The precipitate generated in the coagulation treatment system S11 can be used as sludge, which can be used as building material, fertilizer, etc.

[0058] Regarding the addition of coagulant, if the pH (hydrogen ion concentration) of the raw water in the ozone decomposition treatment system S10 is about 8.5±1.5, it can be added without pH control. If the pH is outside the range of 8.5±1.5, the pH of the raw water can be controlled by any method to bring it within the range.

[0059] In addition, the coagulation treatment system S11 may be configured such that a coagulation sedimentation tank is connected to the ozone decomposition reactor, the ozone-ultraviolet decomposition reactor and / or the ozone catalytic reactor, or a separate coagulation sedimentation tank may be provided for treatment.

[0060] Next, after the coagulation treatment system S11, a filtration treatment system S12 is performed. This sand filtration treatment system S12 is used to remove any sediment that was not completely removed by coagulation and sedimentation. As in the sand filtration treatment, sand is used as the filtering material, and the particle size of the sand is preferably around 50 μm.

[0061] The filtration treatment system S12 may be connected to an ozone decomposition reaction device, an ozone-ultraviolet decomposition reaction device and / or an ozone catalytic reaction device via a conduit or the like, or may be provided with a separate sand filtration treatment device or means for treatment.

[0062] Next, the raw water treated in the filtration system S12 (hereinafter referred to as "pretreated raw water") is introduced into the ozone-ultraviolet decomposition reaction system S13 for treatment. In the present invention, an ozone-ultraviolet decomposition reaction device 4 as shown in Figure 1 or Figure 2 is used to perform ozone microbubble decomposition treatment, ozone microbubble crushing treatment, i.e., ozone nanobubble decomposition treatment, and UV irradiation. As previously described in Figure 1, the pretreated raw water containing ozone microbubbles is pumped through the second and third circulation pumps. The ozone microbubbles are crushed in the crushing tower, resulting in some of the ozone nanobubbles, which are then subjected to microbubble and nanobubble treatment. In other words, the ozone microbubbles and / or ozone nanobubbles oxidize and decompose even the finest organic matter. Furthermore, UV irradiation by the ozone-ultraviolet decomposition reaction system S13 constantly generates hydroxyl radicals or activated acids, or promotes ozone oxidation, resulting in the oxidative decomposition of most organic matter.

[0063] The purpose of UV irradiation in the ozone-ultraviolet decomposition reaction system S13 is, similar to that in the ozone decomposition treatment system S10, to minimize the conversion of ozone to oxygen molecules when some ozone microbubbles remain in the raw water without being crushed. In other words, UV irradiation in the raw water generates reactive oxygen species from ozone. Furthermore, the purpose of UV irradiation in the ozone-ultraviolet decomposition reaction system S13 is to promote reactions with suspended matter and organic fine solid matter when the activated carbon layer described above is not functioning as a catalytic reaction field or when its function needs to be suspended. Reactive oxygen species are known to function similarly to free radicals generated when ozone microbubbles and / or ozone nanobubbles are forcibly crushed, and they play a role in treating organic matter by oxidizing substances other than ozone and oxygen. Furthermore, there are no particular limitations on the wavelength of UV irradiation when treating organic matter, as long as it is in the ultraviolet range (approximately 100 to 380 nm). It is best to irradiate the raw water with UV light in the ozone-ultraviolet decomposition reaction system S13 while it is treating the raw water. The UV irradiation time in the ozone-ultraviolet decomposition reaction system S13 is preferably 2 to 12 hours. If the irradiation time is less than 2 hours, the COD and TOC values ​​will be roughly the same as or not significantly different from those of the raw water, and even if the irradiation time is longer than 12 hours, the efficiency will not increase significantly. At this time, the pH of the raw wastewater or pretreated raw water is preferably in the neutral range of about 6.5 to 7.9. Although UV irradiation is possible in the weakly basic range of pH 8 to 9 or the weakly acidic range of pH around 5, the efficiency is lower than when the water is neutral. This is due to the reactivity of ozone gas and hydroxyl radicals.

[0064] Incidentally, in the ozone-ultraviolet decomposition reaction system S13, the supply rate of ozone gas is also preferably 150 to 600 g / h (hour). If the supply rate of ozone gas is less than 150 g / h, the raw wastewater is hardly treated, and even if the supply rate is more than 600 g / h, the treatment capacity does not change significantly. Furthermore, in the ozone-ultraviolet decomposition reaction system S13, the circulation rate of raw water in the ozone decomposition reaction device 3 is 100 to 200 L / min. If the circulation rate is less than 100 L / min, the collapse of ozone microbubbles is not performed properly, and the raw water is not sufficiently treated. Even if the circulation rate is more than 200 L / min, the treatment capacity does not improve significantly, or may even decrease. Furthermore, the treatment in the ozone-ultraviolet decomposition reaction system S13 is preferably about 1 to 72 hours. If the treatment time is less than one hour, the treatment will be insufficient, and if it is more than 72 hours, the treatment will be sufficient, but it may hasten equipment failure or, depending on the organic matter, may cause an equilibrium reaction to proceed, resulting in the original substance being restored.

[0065] Next, the raw water treated in the ozone-ultraviolet decomposition reaction system S13 (hereinafter referred to as "secondary pretreated raw water") is introduced into the ozone catalytic decomposition treatment system S14 for treatment. In the present invention, the ozone catalytic decomposition treatment system S14 uses an ozone catalytic reaction device 4 as shown in FIG. 1 or 2 to perform decomposition treatment using ozone microbubbles and ozone microbubble crushing treatment, i.e., decomposition treatment using ozone nanobubbles. As previously described in FIG. 1, the pretreated raw water containing ozone microbubbles is pumped through the first and second circulation pumps, and the ozone microbubbles are crushed in a crushing tower, resulting in a portion of the pretreated raw water being converted into ozone nanobubbles, which are then subjected to microbubble and nanobubble treatment. In other words, the ozone microbubbles and / or ozone nanobubbles oxidize and decompose even the finest organic matter. Ultimately, most organic matter (organic fine solid matter and persistent substances) is oxidized. Then, when the ozone catalytic decomposition treatment system S14 is finished, the COD and TOC values ​​are reduced to about 1 / 8 to 1 / 12 of those of the raw water.

[0066] Incidentally, in the ozone catalytic decomposition treatment system S14, the supply rate of ozone gas is also preferably 150 to 600 g / h (hour). If the supply rate of ozone gas is less than 150 g / h, the raw wastewater is hardly treated, and even if the supply rate is more than 600 g / h, the treatment capacity does not change significantly. In the ozone catalytic decomposition treatment system S5, the circulation rate of raw water in the ozone decomposition reaction device 3 is 100 to 200 L / min. If the circulation rate is less than 100 L / min, the collapse of ozone microbubbles is not performed well, and the raw water is not sufficiently treated. Even if the circulation rate is more than 200 L / min, the treatment capacity does not improve significantly, or may even decrease. Incidentally, the treatment in the ozone catalytic decomposition treatment system S14 is preferably about 1 to 72 hours. If the treatment time is less than 1 hour, the treatment will be insufficient, and if it is more than 72 hours, the treatment will be sufficient, but it may hasten equipment failure (especially the activated carbon layer) or, depending on the organic matter, may cause an equilibrium reaction to proceed, resulting in the original substance being restored.

[0067] Furthermore, in the ozone catalytic decomposition treatment system S14, an important point is that a reaction field, a so-called catalytic reaction, occurs between hydroxyl radicals generated from ozone nanobubbles, ozone gas itself, and the final residue contained in the pretreated raw water in the first and second activated carbon layers installed in the ozone catalytic reaction device 5. As mentioned above, pellet-type activated carbon is used for the first activated carbon layer 57, and the diameter (effective diameter) of the activated carbon is 6 to 7 mm. This set range is set larger (longer) than that of the second activated carbon layer 58. On the other hand, pellet-type activated carbon is used for the second activated carbon layer 58, and the diameter (effective diameter) of the activated carbon is 3 to 4 mm. This set range is set smaller (shorter) than that of the first activated carbon layer 57. The reason for this is that if the catalytic reaction does not proceed well in the first activated carbon layer 57, the diameter of the pellet-type activated carbon packed in the second activated carbon layer 58, which has a larger specific surface area, is made smaller than the diameter of the pellet-type activated carbon packed in the first activated carbon layer 57 so that the catalytic reaction can be reliably carried out almost quantitatively in the second activated carbon layer 58. Furthermore, if the diameter of the pellet-type activated carbon is less than 3 mm, the adsorption reaction will prevail over the catalytic activity, and if it is greater than 7 mm, the pretreated raw water may not be able to pass through each layer at a sufficient speed.

[0068] Furthermore, when the pretreated raw water containing the final residue is passed through the first activated carbon layer 57 and the second activated carbon layer 58, it is desirable to pass it through each layer at a flow rate of 10 to 100 cm / sec. If the flow rate is less than 10 cm / sec, the adsorption reaction will prevail over the catalytic reaction, and if the flow rate is faster than 100 cm / sec, neither adsorption nor catalytic reaction will occur. The flow rate can be adjusted by the circulation rate of the fourth circulation pump 53 or the fifth circulation pump 55 shown in FIG. 1, or any flow rate adjustment means can be used.

[0069] Furthermore, backwashing may be performed when operating the ozone catalytic decomposition treatment system S14 and the ozone catalytic decomposition treatment system S15 described later. As described above, the purpose of backwashing is to backwash the first activated carbon layer 57 and the second activated carbon layer 58. There are no particular limitations on the number of backwashes or the backwashing time, as long as the backwashing is performed at least once a week. Backwashing the pelleted activated carbon in the first activated carbon layer 57 and the second activated carbon layer 58 with ozone microbubble-containing water and / or ozone nanobubble-containing water extends the life of the pelleted activated carbon by approximately 8 to 20 times compared to backwashing with water (tap water). Furthermore, batch processing is desirable for backwashing.

[0070] Next, the ozone catalytic decomposition treatment system S14 is followed by the ozone catalytic decomposition treatment system S15. The basic operation is the same as that of the ozone catalytic decomposition treatment system S14. However, if the ozone catalytic decomposition treatment system S14 is not provided after the ozone catalytic decomposition treatment system S14, the final concentrations of COD and THF will not be approximately 1 / 10 to 1 / 20 of those in the raw water. In other words, if the ozone catalytic decomposition treatment system is performed in one stage in this embodiment, the final concentrations of COD, aldehydes, and polar solvents such as THF will remain at approximately 1 / 10 of those in the raw water. Note that the water treated by the ozone catalytic decomposition treatment system S15 can be reused, for example, to dilute the raw water.

[0071] In addition to the embodiment shown in FIG. 3, the order of the filtration process, coagulation process, etc. may be reversed as long as it is observed that in the case of a system, an ozone decomposition treatment system is followed by an ozone-ultraviolet decomposition reaction system and then an ozone catalytic treatment system, and in the case of a method, an ozone decomposition treatment is followed by an ozone-ultraviolet decomposition reaction treatment and then an ozone catalytic treatment.

[0072] As described above, the system can treat wastewater with a COD of 5,000 mg / L or more (up to approximately 150,000 mg / L) or persistent wastewater such as high-concentration acrylic or glass-based wastewater. It can also treat gaseous or liquid persistent substances and polar solvents containing 1,4-dioxane. When using the pretreatment system, a neutralizer such as ammonium chloride can be used for wastewater containing polar solvents such as aldehydes or THF.

[0073] In this way, treatment of gaseous and liquid persistent substances is also possible. Furthermore, when performing a pretreatment system, a neutralizing agent such as ammonium chloride may be used for polar solvent-based wastewater containing aldehydes, 1,4-dioxane, etc. The wastewater final treatment system and wastewater final treatment method according to the present invention are not limited to the embodiments shown in Figures 2 and 3. The order of filtration, coagulation, and other processes may be reversed as long as the system (i.e., a system in which an ozone decomposition treatment system is followed by an ozone-ultraviolet decomposition treatment system and then an ozone catalytic treatment system) is used, and the method (i.e., a method in which ozone decomposition treatment is followed by ozone-ultraviolet decomposition treatment and then ozone catalytic treatment) is used.

[0074] The embodiments of the final treatment device for wastewater containing high concentrations of persistent organic matter, the system using the device, and the final treatment method for wastewater containing high concentrations of persistent organic matter using ozone microbubbles according to the present invention have been described above. However, it goes without saying that various embodiments can be adopted without departing from the scope of the claims, the specification, the drawings, etc. [Example]

[0075] The above-described embodiment will be further described by way of examples. The examples will be described with reference to Figures 1 to 3 depending on the content of the examples. In Examples 1 to 3 below, ozone gas, ozone microbubble, and ozone nanobubble treatments will be referred to as "ozone treatment."

[0076] [Example 1] Wastewater treatment of persistently decomposable wastewater containing polar solvents (ozone treatment) In Example 1, wastewater treatment of polar solvent-containing basic, persistent wastewater was carried out as follows. Here, "polar solvent" mainly refers to 1,4-dioxane, and "polar solvent-containing, persistent wastewater" means wastewater containing a polar solvent such as 1,4-dioxane.

[0077] First, polar solvent-containing, poorly decomposable wastewater with a TOC (total organic carbon) of 1330 mg / L was subjected to ozone treatment for 1 to 4 hours in an ozone decomposition treatment system (ozone decomposition treatment device 3).

[0078] Table 1 shows the changes in the concentrations of TOC and 1,4-dioxane contained in the polar solvent-containing persistent wastewater over time.

[0079] [Table 1]

[0080] First, the TOC value decreased as the ozone treatment time increased, and the 1,4-dioxane concentration decreased as the ozone treatment time increased, reaching approximately 65% ​​of the pre-treatment concentration after 4 hours of ozone treatment.

[0081] [Example 2] Wastewater treatment of basic, persistently decomposable wastewater (coagulation and sedimentation treatment) In Example 2, the wastewater treatment of the basic, persistently decomposable wastewater was mainly carried out by coagulation and sedimentation treatment.

[0082] First, a basic, persistent wastewater containing polar solvents (pH = 11.7, hereinafter referred to as "basic wastewater") with a TOC (total organic carbon) of 1330 mg / L was treated with ozone for 1 hour in an ozone decomposition treatment system (ozone decomposition treatment device 3).

[0083] Next, polyaluminum chloride (PAC) was added to the ozone-treated basic wastewater to perform coagulation treatment, and then an alkali adjuster was added to control the pH between 6.8 and 7.2. Incidentally, the pH at the time of adding PAC was 5.3. The TOC after this treatment was 1010 mg / L.

[0084] In addition, when the ozone treatment time for basic wastewater was extended to 3 hours under the same PAC addition conditions, the TOC was 910 mg / L. However, coagulation and precipitation were less likely to occur compared to when the ozone treatment time was 1 hour.

[0085] In Example 2, it was found that the TOC content of the basic wastewater decreased in proportion to the ozone treatment time, regardless of whether coagulation and precipitation were performed.

[0086] [Example 3] Treatment of polar solvent-based wastewater containing 1,4-dioxane, etc. In Example 3, to confirm the performance of the ozone-ultraviolet decomposition treatment system (ozone-ultraviolet decomposition treatment device 4), wastewater treatment (batch treatment) was carried out using the ozone decomposition treatment system (ozone decomposition treatment device 3) on polar solvent-based wastewater containing 1,4-dioxane and the like, which had been adjusted in advance to a COD of approximately 2000 mg / L and a TOC of approximately 850 mg / L. Note that UV irradiation in the ozone-ultraviolet decomposition treatment system was carried out for 12 consecutive hours, and ozone gas was supplied continuously at a rate of approximately 200 g / h for 12 consecutive hours. As a result, both the COD and TOC were reduced to approximately one-third.

[0087] In this example, the concentration of the wastewater before UV irradiation was approximately 95 mg / L (ppm), but after 8 hours of UV irradiation, it was below 10 ppm, and with subsequent irradiation, the value approached the measurement limit as time passed. [Industrial Applicability]

[0088] From the above, although there is still room for further investigation into the circulation rates of ozone gas, ozone microbubbles, and ozone nanobubbles, the duration of ultraviolet irradiation, and other factors, at least the present invention can be used for the final treatment of wastewater containing not only all kinds of high-concentration organic matter and nitrogen (ammonia and nitrate forms), but also polar solvents such as 1,4-dioxane. Furthermore, it is possible to use not only ozone microbubbles and / or ozone nanobubbles, but also microbubbles and / or nanobubbles of oxygen, nitrogen, etc. Furthermore, the precipitate produced by coagulation and sedimentation can be used as sludge for fertilizer, materials, and the like. [Explanation of symbols]

[0089] 1. Final wastewater treatment equipment 2. Ozone gas generator 3. Ozonolysis reactor 4. Ozone-ultraviolet decomposition reactor 5. Ozone catalytic reactor 31 Ozone decomposition reactor 33 First Microbubble Generator 35 No. 1 Crushing Tower 37 1st activated carbon tower 41 Ozone-ultraviolet decomposition reactor 42 Ultraviolet irradiator 43 Second Microbubble Generator 45 No. 2 Crushing Tower 47 2nd activated carbon tower 51 Ozone catalytic reactor 52 Third Microbubble Generator 54 No. 3 Crushing Tower 56 3rd activated carbon tower 57 1st activated carbon layer 58 2nd activated carbon layer

Claims

1. A final treatment device for wastewater containing high concentrations of persistent organic matter, comprising an ozone generator, an ozone decomposition reactor, an ozone-ultraviolet decomposition reactor, and an ozone catalytic reactor, The ozone decomposition reaction apparatus includes an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower having a punching plate installed therein, a first circulation pump, and a first activated carbon tower; The ozone-ultraviolet decomposition reaction device includes an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second circulation pump, a second crushing tower having a punching plate installed therein, a third circulation pump, and a second activated carbon tower; The ozone catalytic reaction device includes an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower having a punching plate installed therein, a fifth circulation pump, and a third activated carbon tower; the ozone generator is connected to the ejector pump, the first microbubble generator, the second microbubble generator, and the third microbubble generator by an ozone gas supply pipe; the ozone decomposition reaction tank, the ozone-ultraviolet decomposition reaction tank, and the ozone catalytic decomposition tank are connected by an overflow pipe; The ozone catalytic decomposition tank is provided with a first activated carbon layer and a second activated carbon layer, and a backwash water outlet is provided therein.

2. A final treatment device for wastewater containing high concentrations of persistent organic matter, comprising an ozone generator, an ozone decomposition reactor, an ozone-ultraviolet decomposition reactor, and an ozone catalytic reactor, The ozone decomposition reaction apparatus includes an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower having an orifice installed therein, a first circulation pump, and a first activated carbon tower; The ozone-ultraviolet decomposition reaction device includes an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second circulation pump, a second crushing tower having an orifice installed therein, a third circulation pump, and a second activated carbon tower; The ozone catalytic reaction device includes an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower having an orifice installed therein, a fifth circulation pump, and a third activated carbon tower; the ozone generator is connected to the ejector pump, the first microbubble generator, the second microbubble generator, and the third microbubble generator by an ozone gas supply pipe; the ozone decomposition reaction tank, the ozone-ultraviolet decomposition reaction tank, and the ozone catalytic decomposition tank are connected by an overflow pipe; The ozone catalytic decomposition tank is provided with a first activated carbon layer and a second activated carbon layer, and a backwash water outlet is provided therein.

3. 3. The apparatus according to claim 1, wherein the first crushing tower is installed so as to circulate raw wastewater containing ozone microbubbles between the first crushing tower and the ozone decomposition reaction tank through a plurality of pipes.

4. 4. The apparatus according to claim 1, wherein the first activated carbon tower is installed so as to circulate raw wastewater containing ozone gas, ozone microbubbles, and / or ozone nanobubbles between the first activated carbon tower and the ozone decomposition reaction tank through a plurality of pipes.

5. 5. The apparatus according to claim 1, wherein the second crushing tower is installed to circulate raw wastewater containing ozone microbubbles between the second crushing tower and the ozone-ultraviolet decomposition reaction tank through a plurality of pipes.

6. 6. The apparatus according to claim 1, wherein the second activated carbon tower is installed so as to circulate raw wastewater containing ozone gas, ozone microbubbles and / or ozone nanobubbles between the second activated carbon tower and the ozone-ultraviolet decomposition reaction tank through a plurality of pipes.

7. 7. The apparatus according to claim 1, wherein the third crushing tower is installed so as to circulate raw wastewater containing ozone microbubbles between the third crushing tower and the ozone catalytic decomposition tank through a plurality of pipes.

8. 8. The apparatus according to claim 1, wherein the third activated carbon tower is installed so as to circulate raw wastewater containing ozone gas, ozone microbubbles and / or ozone nanobubbles between the third activated carbon tower and the ozone catalytic decomposition tank through a plurality of pipes.

9. 9. The apparatus according to claim 1, wherein the activated carbon packed in the first activated carbon tower, the second activated carbon tower, and the third activated carbon tower is granular activated carbon, and the diameter of the activated carbon is 1 to 2 mm.

10. 10. The apparatus according to claim 1, wherein the activated carbon packed in the first activated carbon layer is pellet-type activated carbon having a diameter of 6 to 7 mm, and the activated carbon packed in the second activated carbon layer is pellet-type activated carbon having a diameter of 3 to 4 mm.

11. 11. The apparatus according to any one of claims 1 to 10, further comprising another ozonolysis reactor and a coagulation and settling tank.

12. A wastewater final treatment system for high-concentration persistent organic matter using the device according to any one of claims 1 to 11, The wastewater final treatment system is an ozone decomposition treatment system that treats raw wastewater using an ozone decomposition reaction apparatus including an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower having a punching plate installed therein, a first circulation pump, and a first activated carbon tower; An ozone-ultraviolet decomposition treatment system for treating the raw wastewater treated in the ozone decomposition treatment system using an ozone-ultraviolet decomposition reaction device including an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second crushing tower having a punching plate installed therein, a third circulating pump, and a second activated carbon tower; an ozone catalytic decomposition system in which the raw wastewater treated by the ozone decomposition treatment system and the ozone-ultraviolet decomposition treatment system is treated by an ozone catalytic reaction device comprising an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower with a punching plate installed therein, a fifth circulation pump, and a third activated carbon tower, and having a first activated carbon layer and a second activated carbon layer installed therein; a catalytic decomposition system for catalytically decomposing the raw wastewater to pass through the first activated carbon layer and the second activated carbon layer at a flow rate of 10 to 100 cm / sec;

13. A wastewater final treatment system for high-concentration persistent organic matter using the device according to any one of claims 1 to 11, The wastewater final treatment system is an ozone decomposition treatment system that treats raw wastewater using an ozone decomposition reaction device including an ozone decomposition reaction tank, a raw water inlet, a first microbubble generator, an ejector pump, a first crushing tower having an orifice installed therein, a first circulation pump, and a first activated carbon tower; An ozone-ultraviolet decomposition treatment system for treating the raw wastewater treated in the ozone decomposition treatment system using an ozone-ultraviolet decomposition reaction device including an ozone-ultraviolet decomposition reaction tank, an ultraviolet irradiator, a second microbubble generator, a second crushing tower having an orifice installed therein, a third circulating pump, and a second activated carbon tower; The raw wastewater treated by the ozone decomposition treatment system and the ozone-ultraviolet decomposition treatment system is fed to an ozone catalytic decomposition tank, a third microbubble generator, a fourth circulation pump, a third crushing tower having an orifice installed therein, a fifth circulation pump, and a third activated carbon tower, an ozone catalytic decomposition system that performs treatment using an ozone catalytic reaction device having a first activated carbon layer and a second activated carbon layer installed therein; a catalytic decomposition system for catalytically decomposing the raw wastewater to pass through the first activated carbon layer and the second activated carbon layer at a flow rate of 10 to 100 cm / sec;

14. 14. The wastewater final treatment system according to claim 12 or 13, further comprising at least one of the ozone decomposition system, a flocculation system, a filtration system, and / or at least the ozone catalytic decomposition system.

15. 15. The wastewater final treatment system according to claim 12, wherein the activated carbon packed in the first activated carbon layer is pellet-type activated carbon having a diameter of 6 to 7 mm, and the activated carbon packed in the second activated carbon layer is pellet-type activated carbon having a diameter of 3 to 4 mm.

16. A method for final wastewater treatment using the system for final wastewater treatment of high-concentration persistent organic matter using ozone microbubbles according to any one of claims 12 to 15, A final treatment method for wastewater containing high concentrations of persistent organic matter, comprising an ozone decomposition treatment step, an ozone-ultraviolet decomposition treatment step, and an ozone catalytic decomposition step, wherein the raw wastewater is irradiated with ultraviolet light for 2 to 12 hours in the ozone-ultraviolet decomposition treatment step.

17. 17. The method for final wastewater treatment according to claim 16, further comprising at least one of the ozonolysis step, the coagulation step, the filtration step, and / or the ozone catalytic decomposition step.

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