JP2012179538A - Apparatus and method for waste water disposal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for waste water disposal which very efficiently disposes of a large amount of waste water containing various kinds of organic matter discharged from actual operations.SOLUTION: The apparatus for waste water disposal includes a treatment tank 1 in which waste water containing organic matter is treated, an ozone oxidation means which turns the organic matter included in the waste water in the treatment tank 1 into carbonyl compounds on oxidation with ozone, a solid-liquid separation means which precipitates the carbonyl compounds obtained by the ozone oxidation means with metal ions, and an ultraviolet irradiation means 4 which promotes the ozone oxidation reaction in the ozone oxidation means on ultraviolet irradiation. In this method, an organic matter is not decomposed, but ozone-oxidized into carbonyl compounds which are separated from the liquid on precipitation by means of chelate reaction with metal ions. This method, therefore, results in a large reduction of ozone consumption and a significant shortening of the treatment time.

Description

  The present invention relates to a wastewater treatment apparatus and method that can efficiently treat wastewater containing organic matter in a short time.

  Wastewater discharged from factories and stores is diversifying with the development of industry, and it is extremely diverse, including washing waste liquid for electronic parts, waste liquid containing machine oil and paint, fat waste liquid for kitchen, washing drainage, etc. Crossing. Many of these contain some organic matter, albeit in varying amounts. For this reason, it is forced to spend equipment, energy, and cost for the treatment of organic matter in wastewater.

It is widely known that ozone can be used as a method for treating organic substances in wastewater. For example, as described in Non-Patent Document 1 (Harumi Yamada; New Technology for Utilizing New Ozone, Sanyu Shobo, p. 51-89, (1993)), organic matter has an oxidizing power and ozone due to ozone itself. Oxidized and decomposed by reacting with OH radicals generated during self-decomposition. The decomposed organic matter undergoes various processes depending on the substance, but eventually becomes CO ₂ and H ₂ O and disappears from the wastewater.

  As a method for promoting this oxidative decomposition reaction, a method using ultraviolet irradiation in combination is also known.

  For example, as described in Non-Patent Document 2 (Kyoto Yoshizaki; Wastewater Sewage Treatment Technology Collection, NTS Publishing, p. 348 to 358, (2007)), the generation of OH radicals is promoted by using ultraviolet rays. can do. OH radicals have stronger oxidizing power than ozone molecules and promote oxidative decomposition. Moreover, since the ultraviolet rays themselves also decompose the organic matter, the decomposition of the organic matter is further promoted.

  On the other hand, patent document 1 (Unexamined-Japanese-Patent No. 2004-237266) is disclosed about the processing method of the wastewater containing organic substance.

In Patent Document 1, in order for an organic substance to be completely decomposed to CO ₂ and H ₂ O, a large amount of ozone must be consumed over a long period of time, so that the organic substance becomes an organic acid without completely decomposing the organic substance. It is disclosed that the treatment is made more efficient by oxidation with ozone until the organic acid is chelated by administration of calcium ions or the like in water and the precipitate is removed.

  Patent Document 2 (Japanese Patent Laid-Open No. 2003-202396) and Patent Document 3 (Japanese Patent Laid-Open No. 2001-232383) disclose a wastewater treatment method using ozone and calcium in combination.

  Patent Document 2 discloses that when oxalic acid, which is an organic acid, is precipitated by adding calcium ions to precipitate it, ultraviolet rays are irradiated while blowing oxygen gas to convert oxygen into ozone, and the ozone is used to convert oxalic acid. It is disclosed that the generation of precipitates is suppressed by decomposing a part of the acid.

Patent Document 3 discloses that MnO ₂ is used as a catalyst for decomposing organic substances with ozone, and that the treatment is made efficient by activating the catalytic action of MnO ₂ by adding a calcium component. ing.

JP 2004-237266 A JP 2003-202396 A JP 2001-232383 A

Harumi Yamada; New technology using ozone, Sanyu Shobo, p. 51-89, (1993) Kozaki Yoshizaki; Wastewater Sewage Treatment Technology Assembly, NTS Publishing, p. 348-358, (2007)

  Patent document 1 oxidizes with ozone until it becomes an organic acid without completely decomposing the organic substance, and the organic acid is chelated by administering calcium ions or the like into water to improve the processing efficiency by removing the precipitate. Is. However, the technique disclosed in Patent Document 1 is merely a basic concept, and it is not realistic to try to implement actual wastewater treatment industrially using only the basic concept disclosed herein.

  Patent Document 2 specializes in the treatment of oxalic acid, which is the main component of the decontamination solution used in the “CORD method”, which is a chemical decontamination method for radioactive corrosion products adhering to the primary cooling water pipes of nuclear power plants, etc. It is what. In order to reduce the volume of the precipitate caused by oxalic acid, first, a part of oxalic acid is decomposed with ozone, then calcium and alkaline substances are added, and the remaining oxalic acid and metal ions that have not been decomposed are added. It is what is precipitated. Therefore, it is not possible to treat a large amount of waste water containing organic substances having a large molecular weight that are discharged in actual operation.

Patent Document 3 uses a MnO ₂ catalyst as an accelerator for the oxidation reaction by ozone. Hydroxyl radical (OH.) Is generated by MnO ₂ catalyst, and organic wastewater is oxidatively decomposed more powerfully than ozone. In order to activate the catalytic action of MnO ₂ , calcium is added to shorten the complete decomposition time of the organic matter. However, as described in the literature, COD of about 30 mg / L can only be reduced to about 10 mg / L with raw water. Therefore, a large amount of waste water having a high COD value discharged in actual operation cannot be treated.

The present invention has been made to solve the above-described problems, and provides a wastewater treatment apparatus and method capable of treating a large amount of wastewater containing various organic substances discharged in actual operation extremely efficiently. With the goal.

In order to achieve the above object, a wastewater treatment apparatus of the present invention comprises a treatment tank for treating wastewater containing organic matter,
Ozone oxidation means that oxidizes organic matter in waste water in the treatment tank by the action of ozone into a carbonyl compound;
Solid-liquid separation means for precipitating and separating the carbonyl compound obtained by the ozone oxidation means with metal ions;
The gist of the invention is that it comprises ultraviolet irradiation means for accelerating the oxidation reaction of ozone in the ozone oxidation means by ultraviolet irradiation.

In order to achieve the above object, the wastewater treatment method of the present invention comprises an ozone oxidation step in which organic matter in wastewater is oxidized by the action of ozone to form a carbonyl compound;
A solid-liquid separation step of separating the carbonyl compound obtained in the ozone oxidation step by precipitation with metal ions,
The gist is to promote the oxidation reaction of ozone in the ozone oxidation step by ultraviolet irradiation.

The present invention relates to ozone oxidation in which the organic matter in waste water is oxidized by the action of ozone to form a carbonyl compound, and the carbonyl compound obtained by the ozone oxidation is precipitated with metal ions and solid-liquid separated. Ozone oxidation reaction is accelerated by UV irradiation.
In this way, the organic matter is not completely decomposed, but what is oxidized to the carbonyl compound by ozone oxidation is precipitated by a chelate reaction with metal ions to perform solid-liquid separation. Therefore, ozone consumption can be greatly reduced as compared with the conventional complete decomposition process. Moreover, since the oxidation reaction of ozone is accelerated by ultraviolet irradiation, the processing time can be greatly shortened. Therefore, even a large amount of industrial wastewater with a high COD value, such as wastewater in actual operation, can be treated below the discharge limit in a short time.

In the present invention, the ultraviolet irradiation means, in the circulation path for circulating the waste water in the treatment tank, when an ultraviolet lamp is disposed inside the ultraviolet permeable double tube structure forming a cylindrical flow path,
Ultraviolet irradiation can be performed while circulating the waste liquid, and the ozone oxidation reaction by ultraviolet light can be promoted extremely efficiently.

In the present invention, the solid-liquid separation means includes a metal ion supply unit that supplies the metal ion source to the wastewater as a powder or a slurry, and a chelate reaction that generates a precipitate by stirring and / or circulating the wastewater in the treatment tank. If it is configured with a reaction promoting part to promote,
Metal ions are easily supplied to the waste liquid and diffused smoothly, the liquid quality is made uniform, and precipitates are generated quickly, thereby contributing to shortening of the processing time.

In the present invention, when the ozone oxidation means is configured to include an ozone generator and a gas-liquid contact portion for contacting ozone with wastewater in the processing tank and / or the circulation path,
Oxidation of organic substances to carbonyl compounds by ozone oxidation is carried out easily and smoothly, and precipitates are rapidly generated to contribute to shortening the processing time.

In the present invention, when the solid-liquid separation step uses calcium oxide as a metal ion source,
The complex-forming metal ions can be supplied at a low cost and the pH can be controlled, and the chelation reaction can be promoted to further improve the processing efficiency.

In the present invention, when the ultraviolet irradiation is started at a stage where a certain amount of solid-liquid separation has proceeded,
Solid-liquid separation proceeds to some extent, and ultraviolet irradiation is performed in a state where there is no turbidity due to bubbles or solids in the waste liquid, so that the reaction of unreacted ozone and organic matter can be performed more effectively, and the irradiation efficiency is improved.

In the present invention, UV irradiation is performed when UV irradiation is performed on a liquid that has been solid-liquid separated in a circulation path.
The waste liquid with less turbidity after separating the solid content can be irradiated with ultraviolet rays, and the irradiation efficiency of ultraviolet rays is improved.

In the present invention, the ultraviolet irradiation is performed when the supplied ozone is irradiated with ultraviolet rays with respect to the liquid obtained by gas-liquid separation in the treatment tank.
Irradiation with ultraviolet rays can be performed without turbidity caused by bubbles, and the irradiation efficiency of ultraviolet rays is improved.

It is a figure showing the whole wastewater treatment equipment composition of a 1st embodiment of the present invention. It is a figure which shows the specific structure of an ultraviolet irradiation means. It is a figure which shows the specific structure of a solid-liquid separator. It is a figure explaining the driving | running state of the said wastewater treatment apparatus. It is a figure which shows the whole waste-water-treatment apparatus structure of 2nd Embodiment of this invention. It is a diagram which shows the processing result of an Example.

  Next, an embodiment for carrying out the present invention will be described.

  FIG. 1 is a schematic diagram showing the overall configuration of the wastewater treatment apparatus according to the first embodiment of the present invention.

  This apparatus includes a treatment tank 1 for treating waste water containing organic matter, an ozone supply device 2 for performing ozone oxidation to oxidize organic matter in waste water in the treatment tank 1 by the action of ozone into a carbonyl compound, The solid-liquid separation device 3 for precipitating the carbonyl compound obtained by the ozone oxidation with metal ions and separating it, and the ultraviolet irradiation means 4 for accelerating the oxidation reaction of ozone in the ozone oxidation by ultraviolet irradiation. .

  The processing tank 1 communicates with a waste liquid introduction path 11 for introducing a waste liquid to be treated, a circulation path 12 for circulating the introduced waste liquid, and a treatment liquid discharge path 13 for discharging the treated liquid. A lead-out path 14 for leading the liquid in the processing tank 1 is connected to the lower part of the processing tank 1 in common with the circulation path 12 and the processing liquid discharge path 13. A common flow path 15 is provided so as to be common to the waste liquid introduction path 11, the circulation path 12, and the processing liquid discharge path 13 and to communicate with the outlet path 14. The common flow path 15 is provided with a pressure pump 16 that pumps the liquid. The pressure feed pump 16 introduces the waste liquid into the processing tank 1 through the waste liquid introduction path 11, circulates the waste liquid being processed through the circulation path 12, and discharges the processed processing liquid through the processing liquid discharge path 13. When driven.

  The circulation path 12 is provided with an ozone supply device 2, an ultraviolet irradiation means 4, and a solid-liquid separation device 3.

  In this example, the ozone supply device 2 includes an ozone generator 25 and a gas-liquid mixer 26, and functions as the ozone oxidation means of the present invention. Ozone generated in the ozone generator 25 is supplied to a gas-liquid mixer 26 provided in the middle of the circulation path 12, and ozone is supplied to waste water circulating in the circulation path 12.

  Ozone oxidation is performed to oxidize organic substances in the waste liquid to carbonyl compounds by supplying ozone.

  The ozone generator 25 can use a device that generates ozone by using a concentrated oxygen gas as a raw material and discharging it by applying a high voltage between quartz double tubes. Specifically, for example, model number V-80 manufactured by AirTree Ozone Technology Co., Ltd. can be used. Oxygen gas supplied as a raw material to the ozone generator 25 has a high oxygen purity, that is, an oxygen concentration of 90% or more because the higher the concentration of ozone, the higher the processing efficiency during the subsequent gas-liquid mixing. Is desirable.

  As the gas-liquid mixer 26, an ejector, an air turbo mixer, or the like can be used. Specifically, an ejector (manufactured by IBS Co., Ltd., model number 283) or the like can be used. Such a gas-liquid mixer 26 is selected based on a balance between processing efficiency and cost. If the content of the organic substance to be processed is high, the process proceeds even if the bubble diameter is large. The smaller the diameter, the more efficient the treatment with respect to the amount of ozone used. In general, since a gas-liquid mixer capable of miniaturizing bubbles costs more, an appropriate device may be selected according to the processing level.

  FIG. 2 is a cross-sectional view illustrating details of the ultraviolet irradiation means 4.

  The ultraviolet irradiation means 4 includes an ultraviolet lamp 31 disposed inside an ultraviolet transmissive double tube structure that forms a cylindrical flow path 30 in the circulation path 12 for circulating the waste water in the treatment tank 1. .

  In this example, a branch circulation path 27 is provided before and after the gas-liquid mixer 26 in the circulation path 12, and the ultraviolet irradiation means 4 is provided in parallel with the gas-liquid mixer 26.

  The ultraviolet lamp 31 is covered with an ultraviolet transmissive inner cylinder 32, and a cylindrical flow path 30 is formed between the ultraviolet lamp 31 and the outer cylinder 33. The front and back of the cylindrical flow path 30 are covered with a lid 34. Thus, the ultraviolet lamp 31 irradiates the treatment liquid with ultraviolet rays from the inside. As such an ultraviolet irradiation means 4, for example, a flowing water sterilizer (DN Lighting, Model No. 200UA) can be cited, but water supply UV disinfection devices can also be used.

  By this ultraviolet irradiation, the ozone oxidation reaction by the ozone supplied by the ozone supply device 2 is promoted, and the oxidation of organic substances in the waste water to the carbonyl compound is promoted.

  As solid-liquid separation means of the present invention, the metal ion source 21 for supplying the metal ion source to the waste water as a powder or slurry, the solid-liquid separation device 3, and the waste water in the treatment tank 1 are stirred and / or circulated to form a precipitate. And a reaction promoting unit that promotes the chelate reaction to be generated.

  The metal ion supply unit 21 is connected to the processing tank 1. By supplying metal ions to the waste liquid, the carbonyl compound obtained by the above-described ozone oxidation is precipitated by a chelate reaction, and solid-liquid separation is performed. The metal ion supply unit 21 includes a supply tank, a supply path 22 and a supply pump 23 (not shown).

  In addition to Ca, cations used in the chelation reaction include Mg, Al, etc. As the metal ion source, various substances can be applied as long as they can be dissolved in waste liquid and supplied with metal ions. . In particular, Ca, Mg, and Al can be effectively used in this embodiment in which ultraviolet irradiation treatment is performed because the liquid is less colored when forming a complex. Examples of the substance that becomes the source of these cations include calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, and aluminum hydroxide.

  It is particularly preferable to use calcium oxide as the metal ion source. Calcium oxide is preferably used because it is inexpensive and the aqueous solution becomes alkaline. This is because the chelation reaction is alkaline and works efficiently. Further, from the viewpoint of easy supply and diffusion into the treatment liquid, it is preferable to supply calcium oxide or the like as a slurry. The slurry can be adjusted by charging 100 g of powder such as calcium oxide to 1 L of tap water and constantly stirring at a stirring speed of 300 rpm.

  The processing tank 1 is provided with an exhaust gas passage 17 for discharging exhaust gas, a pH meter 18 for detecting the pH of waste liquid being processed, and an ozone concentration meter 19 for detecting the ozone concentration in the gas phase in the processing tank 1. .

  The treatment tank 1 plays the role of diffusion of calcium oxide and the like and gas-liquid separation, and is designed to stir the waste liquid by a swirling flow by a water flow. At this time, the waste liquid in the processing tank 1 is circulated by a pressure feed pump 16 as a circulation pump to circulate the waste liquid to create a water flow, which is stirred. The waste liquid circulation structure that performs this stirring action functions as the reaction promoting portion of the present invention.

  The solid-liquid separation device 3 is provided on the upstream side of the ozone supply device 2 and the ultraviolet irradiation means 4 in the circulation path 12. The solid-liquid separation device 3 is configured to separate a precipitate obtained by chelating a carbonyl compound obtained by ozone oxidation with a metal ion supplied from a metal ion supply unit 21 from a liquid.

  FIG. 3 is a specific example of the solid-liquid separator 3.

  FIG. 3A shows a case where a precipitate is filtered by a bag filter 36 and solid-liquid separation is performed. The bag filter 36 captures solids such as reaction precipitates, prevents deterioration of ozone oxidation efficiency due to diffusion of organic solids, and prevents suspension during ultraviolet irradiation. The filter used here is about 5 μm, and for example, model number FGFSIA-20-E005B manufactured by SMC Corporation can be used. In addition to the bag filter 36, a micromesh filter or the like may be used. These filters can be switched to another system when, for example, five systems are assembled in parallel, and the differential pressure before and after the filtration increases and the filtration efficiency decreases. After switching, replace the filter with a new one for the clogged system.

FIG. 3B includes a precipitation tank 37 and a filtration tank 38, and a flocculant is added to the waste liquid once stored in the precipitation tank 37 to collect the precipitate as a flock. The supernatant is returned to the circulation path 12 and the collected floc is filtered through a mesh to return the filtrate to the circulation path 12.
For example, after the treatment is started, an appropriate amount (specifically, 1/10 of the treatment liquid amount) is transferred from the treatment tank 1 to the precipitation tank 37, and an appropriate amount of the flocculant is charged into the precipitation tank 37, and the rotation speed is set to 1000 rpm or more with a stirrer. Then, rapid stirring is performed for several minutes (2 to 3 minutes) to diffuse the flocculant into the liquid. Next, in order to grow the floc, the rotation speed is set to 300 rpm, and the mixture is stirred for several minutes (2 to 3 minutes). After stirring, the mixture is allowed to stand for an appropriate time (10 minutes at this scale) to allow the flocs to settle. After that, the floc accumulated at the bottom of the precipitation tank 37 is dropped into a filtration tank 38 with a metal mesh of 250 μm mesh together with the liquid volume 1/100 of the liquid volume received in the precipitation tank 37 to separate the floc and liquid into solid and liquid. . The liquid separated into solid and liquid is returned to the processing tank 1 by a pump. This process is repeated periodically (specifically, every 20 minutes) to perform solid-liquid separation.

  FIG. 3 (C) includes a centrifugal separation tank 39 and a filtration tank 38, and returns the liquid separated by centrifugation to the circulation path 12. The collected sediment is filtered with a filter medium and the filtrate is circulated in the circulation path 12. Return to.

  The treatment liquid discharge path 13 is provided with a final filter 41 for collecting the solid content that cannot be completely removed by the solid-liquid separation device 3 in the upstream portion. As the final filter 41 used here, for example, a mesh opening having a size of about 1 μm, for example, an industrial filter (model number FGDCA-03-B001B, manufactured by SMC Corporation) can be used. A micromesh filter or the like may be used.

  In this example, the ultraviolet irradiation means 4 is disposed downstream of the solid-liquid separation device 3 in the circulation path 12, and the ultraviolet irradiation is performed on the liquid solid-liquid separated in the circulation path. The waste liquid with less turbidity can be irradiated with ultraviolet rays, and the irradiation efficiency of ultraviolet rays is improved. Moreover, since the ultraviolet irradiation means 4 is arranged in parallel with the ozone supply device 2 and the ultraviolet rays are irradiated while circulating the liquid obtained by separating ozone and the like in the processing tank 1, the ultraviolet irradiation is performed without any turbidity caused by bubbles. And the irradiation efficiency of ultraviolet rays is improved.

  FIG. 4 is a diagram illustrating a state in which a treatment method is performed using the above-described wastewater treatment apparatus.

  FIG. 4A shows a state in which waste liquid is introduced. The pressure pump 16 is operated to inject the waste liquid from the common flow path 15 and the waste liquid introduction path 11 to the processing tank 1 to a certain amount.

FIG. 4B shows a state in which solid-liquid separation is performed by a chelate reaction between ozone oxidation by supplying ozone and a carbonyl compound obtained by ozone oxidation.
The waste liquid of the processing tank 1 is circulated by repeatedly returning to the processing tank 1 through the common flow path 15 and the circulation path 12 through the outlet path 14.
At this time, ozone is supplied to the circulating waste liquid by the ozone supply device 2, and the organic matter in the waste liquid is oxidized with ozone to become a carbonyl compound.
Metal ions for chelating the carbonyl compound are supplied from the metal ion supply unit 21 by calcium oxide.
The precipitate of the metal complex generated by the chelate reaction is subjected to solid-liquid separation by the solid-liquid separation device 3, and only the liquid returns to the processing tank 1 via the circulation path 12.
In the treatment tank, gas-liquid separation is performed, and unreacted exhaust gas such as ozone and oxygen gas is discharged from the exhaust gas passage 17.

  At this time, the CaO slurry is introduced to supply cations necessary for pH control and chelate reaction. However, if excessively supplied, the burden on the solid-liquid separator 3 increases, so that the pH becomes about 9 to 11. It is preferable to adjust the input amount by ON / OFF control of the supply pump. The pH is controlled by adjusting the input amount of CaO in order to keep the solution that becomes acidic by oxidation with ozone to be alkaline, which is advantageous for the chelate reaction, and is adjusted to pH 10 from the balance with the burden on the solid-liquid separator 3. I keep it at a certain level.

FIG. 4C shows a state in which ultraviolet irradiation is started.
In the state shown in FIG. 4B, when organic substances have been removed to some extent, waste liquid is flowed to the ultraviolet irradiation means 4 through the branch circulation path 27 and irradiated with ultraviolet rays while continuing the above-described processing.

FIG. 4D shows a state in which the waste liquid treatment is finished when the organic substance concentration becomes equal to or lower than the discharge reference value, and the treatment liquid is discharged. The processing liquid in the processing tank 1 is discharged through the outlet path 14, the common flow path 15, and the processing liquid discharge path 13. At this time, when the treatment liquid passes through the final filter 41, the solid content that could not be removed is collected.
In addition, the emission standard is decided according to the situation such as the emission regulation at the time of release or the case of reuse in the house.

  FIG. 5 shows a wastewater treatment apparatus according to the second embodiment of the present invention.

  This example is basically the same as that of the first embodiment, but the configuration of the ozone supply device 2 is slightly changed. The ozone generated by the ozone generator 25 is pressurized and dissolved in the waste liquid by the pressure dissolving device 43 provided in the circulation path 12, and when the waste liquid in which ozone is pressure-dissolved is returned to the treatment tank 1, the swirl nozzle 45. Thus, a swirl flow is generated while generating micro-nano bubbles. In addition, ozone generated by the ozone generator 25 is supplied by bubbling into the processing tank 1 by the bubbling device 44 via the ozone supply path 46. This embodiment also has the same effects as those of the first embodiment.

  As described above, the present technology oxidizes organic matter with ozone and oxidizes to a carbonyl compound, deposits it as a chelate complex with a metal cation, gas-liquid separates in a treatment tank, and filters the solid content with a filter. The filtrate is irradiated with ultraviolet rays (acceleration of reaction by OH radicals and decomposition effect of organic substances by photolysis). Thus, it is an apparatus that effectively combines ozone oxidation, chelation reaction, and ultraviolet treatment for removing organic substances in wastewater, and is effective in shortening the treatment time and reducing the amount of ozone used.

As an example, electronic component cleaning wastewater was treated. Calcium oxide was used as the metal ion source, and the treatment was performed by the above-described apparatus according to the above-described procedure.
[Processing conditions]
Treatment liquid volume 160L
Gas-liquid mixer Coaxial mixer Circulating fluid volume 80L / min
Oxygen-ozone mixed gas amount: 15 L / min
Ozone gas concentration 80 g / Nm ³

  FIG. 6 and Table 1 show a state in which the COD decreases according to the processing time in the above processing.

  In this example, an organic substance contained in a cleaning agent diluted with pure water or the like at the time of cleaning is a processing target. The COD of the discharged wastewater is 1716 mg / L. When the treatment is performed in the above-described treatment process, in the situation where the COD is high for up to 4 hours after the treatment starts, it becomes the core of the chelate reaction with the oxidized organic matter. Ca ion reacts efficiently and COD decreases rapidly. Thereafter, organic matter removal by the chelate reaction proceeds slowly until the organic matter disappears. When the C concentration of the precipitate collected by filtration was measured, the amount of C corresponding to the TOC of the stock solution was included. Therefore, it is considered that the organic matter was solid-liquid separated by a chelate reaction. (However, it is not the analysis of the precipitate of the processing solution given in the example, but the material balance when processing on another day, and the processing at that time is in the middle of processing, so it is difficult to list in a specific example. )

  For the COD analysis, a simple COD meter COD-60A manufactured by TOA DKK was used. This analyzer is a coulometric titration method, and Fe (iii) present in the reagent 1 is reduced to Fe (ii) by constant current electrolysis, and the produced Fe (ii) reacts with potassium permanganate of the reagent 2. The time when the finally remaining potassium permanganate has completely reacted with Fe (ii) is obtained as the titration end point, and the concentration is calculated from the amount of electricity required so far.

As described above, in this embodiment, the following effects are obtained.
・ By using chelate reaction, processing time and ozone consumption were reduced compared to complete decomposition.
-By using a slurry of calcium oxide, it is possible to supply complex-forming metal ions and control pH at low cost.
・ Irradiation efficiency improved by UV irradiation after gas-liquid separation and solid-liquid separation.
-The water quality was made uniform by creating a water flow with a circulation pump, and the reaction proceeded efficiently.

Overall, COD 1716 mg / L wastewater can be reduced to 10 mg / L or less in 12 hours, and 1 mg / L or less can be achieved in 22 hours. Even high COD values and large amounts of industrial wastewater, such as those found in wastewater, can be treated in a relatively short time.

1: Treatment tank 2: Ozone supply device 3: Solid-liquid separation device 4: Ultraviolet irradiation means 11: Waste liquid introduction path 12: Circulation path 13: Treatment liquid discharge path 14: Derivation path 15: Common flow path 16: Pressure feed pump 17: Exhaust gas path 18: pH meter 19: Ozone concentration meter 21: Metal ion supply unit 22: Supply channel 23: Supply pump 25: Ozone generator 26: Gas-liquid mixer 27: Branch circuit 30: Cylindrical channel 31: UV lamp 32: inner cylinder 33: outer cylinder 34: lid 36: bag filter 37: precipitation tank 38: filtration tank 39: centrifuge tank 41: final filter 43: pressure dissolution apparatus 44: bubbling device 45: swivel nozzle 46: Ozone supply path

Claims (11)

A treatment tank for treating waste water containing organic matter;
Ozone oxidation means that oxidizes organic matter in waste water in the treatment tank by the action of ozone into a carbonyl compound;
Solid-liquid separation means for precipitating and separating the carbonyl compound obtained by the ozone oxidation means with metal ions;
A wastewater treatment apparatus comprising: an ultraviolet irradiation means for accelerating an oxidation reaction of ozone in the ozone oxidation means by ultraviolet irradiation.   2. The wastewater treatment apparatus according to claim 1, wherein the ultraviolet irradiation means includes an ultraviolet lamp disposed in an ultraviolet permeable double tube structure forming a cylindrical flow path in a circulation path for circulating the wastewater in the treatment tank. .   The solid-liquid separation means promotes a chelate reaction that generates a precipitate by stirring and / or circulating the waste water in the treatment tank and supplying a metal ion source to the waste water as a powder or slurry. The waste water treatment apparatus according to claim 1 or 2, comprising the unit.   The said ozone oxidation means is equipped with the ozone generator and the gas-liquid contact part for making wastewater and ozone in a processing tank and / or a circulation path contact, and is comprised. The wastewater treatment apparatus described in 1.   The wastewater treatment apparatus according to any one of claims 2 to 5, wherein the ultraviolet irradiation means irradiates the liquid separated into solid and liquid in the circulation path with ultraviolet rays.   The wastewater treatment apparatus according to any one of claims 1 to 6, wherein the ultraviolet irradiation means irradiates the supplied ozone with ultraviolet rays to a liquid obtained by gas-liquid separation in a treatment tank. An ozone oxidation process in which organic matter in wastewater is oxidized by the action of ozone into a carbonyl compound;
A solid-liquid separation step of separating the carbonyl compound obtained in the ozone oxidation step by precipitation with metal ions,
A wastewater treatment method characterized by accelerating an oxidation reaction of ozone in the ozone oxidation step by ultraviolet irradiation.   The wastewater treatment method according to claim 7, wherein the solid-liquid separation step uses calcium oxide as a metal ion source.   The wastewater treatment method according to claim 7 or 8, wherein the ultraviolet irradiation is started at a stage where a certain amount of solid-liquid separation is advanced.   The wastewater treatment method according to any one of claims 2 to 5, wherein the ultraviolet irradiation is performed by irradiating the liquid separated into solid and liquid in the circulation path with ultraviolet rays.   The wastewater treatment method according to any one of claims 1 to 6, wherein the irradiation with ultraviolet rays is performed by irradiating the supplied ozone with ultraviolet rays to a liquid obtained by gas-liquid separation in a treatment tank.

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