JP2009262122A - Apparatus for water treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for water treatment capable of purification treatment of water by efficiently decomposing organic substances contained in the water as impurities. <P>SOLUTION: In an oxidation-promotion process in which an oxidation agent 28 in the water 13 to be treated is irradiated with ultraviolet rays, the water undergoes through not only the irradiation but also aeration. Large amounts of organic substances can efficiently be decomposed with strongly oxidizing hydroxy radicals 29 efficiently generated in large quantities by the ultraviolet irradiation and diffused in a wide range by the aeration bubbles. By providing an activated carbon treatment process following the oxidation-promotion process, the long life-span of the activated carbon of the activated carbon treatment process can be achieved due to the oxygen introduced by the aeration, and at the same time, the reducing treatment of the oxidizing agent 28 used in the oxidation-promotion process can be carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water treatment apparatus, and more particularly, an accelerated oxidation treatment (AOP) for the purpose of recovering as pure water production and industrial water using RO membrane apparatus using treated water of groundwater and organic wastewater containing humins as raw water. ) Device and its peripheral devices.

  Groundwater contains persistent organic substances. This organic matter becomes a chromaticity component and causes a yellowish appearance. In the water treatment in which the raw water is finally converted into pure water or the like, it is necessary not only to remove the chromaticity component but also to fundamentally decompose and remove the organic matter. Many organic substances that cause this chromaticity component are called humins. Humins are not specified as compounds, and are classified into humic acids having a molecular weight of thousands to tens of thousands and fulvic acids having molecular weights of thousands to hundreds. Fulvic acid is difficult to remove by coagulation and cannot be removed by coagulation precipitation or filtration. Further, although it is adsorbed by activated carbon, re-release may occur relatively early, or water quality may deteriorate due to rot by microorganisms in the activated carbon tank. If there is a purification device using RO: Reverse Osmosis Membrane (reverse osmosis membrane) in the subsequent stage, these humins adhere to the RO membrane and cause trouble. In organic wastewater recovery, persistent organic substances such as surfactants remaining in the wastewater often cause troubles to adhere to the RO membrane like humic acid. Recently, due to the low pressure of the RO membrane, the material of the membrane has become a synthetic organic membrane, and those having a surface charge are becoming mainstream. Due to this surface potential relationship, colloidal substances such as fulvic acid are more likely to adhere to the RO membrane surface, causing membrane contamination that is difficult to recover by cleaning.

  Various improvements have been made for the above problems. The current state of RO membrane pretreatment of groundwater containing humins is outlined below.

  The agglomeration treatment method is a method of sand filtration after solidification separation by agglomeration sedimentation or pressurized flotation and adsorbing to activated carbon. However, in this method, the chromaticity component finally depends on the adsorption treatment with activated carbon, and as described above, there are not a few troubles such as re-releasing or humic rot in the activated carbon tank. On the other hand, the method of oxidizing and filtering with a catalyst can be decolorized, but since humins are not removed, it is not a fundamental solution. Similarly, the method of combining activated carbon with filtration does not ultimately completely decompose the organic matter. In the ion exchange method, an ion exchange treatment with an anion resin is performed after sand filtration, but the resin is likely to be subjected to organic contamination, leading to an early decrease in the exchange capacity and possibly resulting in a decrease in the amount collected. As described above, each method has advantages and disadvantages, and does not lead to a fundamental solution.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 7-284799 A

  The present invention solves the above problems, decomposes humic acids and fulvic acids, which are humins, with very high efficiency, and generates pure water, ultrapure water, or the like having high purity from raw water containing organic substances. In particular, a water treatment apparatus suitable for filtering treated water without causing clogging in the RO membrane is provided.

  The present invention has an advanced oxidation process (AOP) water treatment tank. The accelerated oxidation tank has an ultraviolet light source for promoting oxidation. Further, aeration is performed in the treated water near the ultraviolet light source. Aeration is to supply gas into water and generate bubbles.

  In the accelerated oxidation treatment, ultraviolet rays and various oxidizing agents are combined to accelerate the oxidizing action and decompose various organic substances. As the oxidizing agent, ozone, chlorine, hydrogen peroxide, or the like is used. These oxidizing agents generate hydroxy radicals having a strong oxidizing action when exposed to ultraviolet rays. However, the effective transmission distance of ultraviolet rays that cause this reaction is generally short. In general, ultraviolet rays are greatly attenuated in water. For example, in cloudy seawater, the transmittance drops to 50% at about 2 cm. In industrial water, the transmittance drops to 50% at about 3 cm. Even in clear seawater, the transmittance drops to 50% at about 7 cm. Even in the treatment using groundwater as raw water, the effective distance of ultraviolet rays effective for the above-described oxidation action is expected to be substantially several centimeters. In other words, organic matter decomposition by the accelerated oxidation reaction usually occurs only in the immediate vicinity of the ultraviolet light source. This is very inefficient.

  In the present invention, bubbles are generated by aeration in the vicinity of the ultraviolet light source, and the treated water in the vicinity of the ultraviolet light source is stirred and diffused by the aeration. That is, the treated water whose oxidation has been promoted by ultraviolet rays and an oxidizing agent diffuses. Therefore, instead, the treated water that has not been promoted for oxidation approaches the vicinity of the ultraviolet light source, and the ultraviolet rays are sufficiently irradiated to promote the oxidation. And it is diffused by aeration. Such a process of replacement is repeated, more treated water is accelerated and oxidized, and organic matter is decomposed.

  At the same time, by generating bubbles by aeration in the vicinity of the ultraviolet light source, the activated oxidant in the vicinity of the ultraviolet light source is also stirred and diffused. Accordingly, the treated water relatively far from the ultraviolet light source is also accelerated and oxidized by the activated oxidant. That is, accelerated oxidation is performed over a wide range, and decomposition of organic substances is further accelerated.

  With this configuration, in the water treatment apparatus of the present invention, more treated water is accelerated and oxidized, so that the decomposition of humic acids and fulvic acid, which are organic substances, proceeds efficiently, and high-purity pure water or ultrapure water is obtained. It becomes easy.

(Embodiment 1)
Hereinafter, the water treatment apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration block diagram of the entire water treatment apparatus according to Embodiment 1 of the present invention. In FIG. 1, raw water 11 such as groundwater is introduced into a sand filtration tank 12. In short, the sand filtration tank 12 has a layer of sand 37 on a layer of gravel 38. The raw water 11 that has been sand-filtered is introduced into the subsequent accelerated oxidation tank 15. Immediately before the sand filtration tank 12, an oxidant addition device 14a for adding an oxidant, a bactericide and a flocculant to the raw water 11 is installed.

  Sodium hypochlorite and ozone are added as an oxidizer and fungicide. PAC (polyaluminum chloride) or sulfuric acid band (aluminum sulfate) is added as a flocculant. With these additives, more impurities can be captured and filtered in the sand filtration tank 12. The oxidizing agent also contributes to the reaction in the accelerated oxidation tank 15 described later.

  The water to be treated after sand filtration will be referred to as treated water 13. Before the treated water 13 is introduced into the accelerated oxidation tank 15, an oxidant addition device 14 for adding an oxidant 28 is installed. The accelerated oxidation tank 15 is provided with an ultraviolet light source 23 therein. Ultraviolet rays are radiated from the ultraviolet light source 23 to the treated water 13. Further, the accelerated oxidation tank 15 is provided with a large number of ejection holes for the aeration gas 27 on the bottom surface 15a, and the gas 27 is ejected. An activated carbon treatment tank 16 is provided following the accelerated oxidation tank 15.

  The treated water 13 is introduced into the activated carbon treatment tank 16 from the accelerated oxidation tank 15. The activated carbon treatment tank 16 is filled with activated carbon 31. Further, an RO membrane separation device 17 is provided at the subsequent stage of the activated carbon treatment tank 16. In the RO membrane separator 17, a reverse osmosis membrane (RO membrane 33) is provided, and the treated water 13 introduced from the activated carbon treatment tank 16 passes through the RO membrane 33. The treated water 13 that has passed becomes purified water 18.

  Next, a water treatment process will be described. The raw water 11 enters a sand filtration tank 12 after adding a flocculant such as PAC and sterilization and oxidation such as sodium hypochlorite. The sand filtration tank 12 filters large solids that become suspended substances. At this point, humic acids and fulvic acids, which are fine organic substances that cause yellowish color and the like, are not removed.

  Next, the treated water 13 is introduced into the accelerated oxidation tank 15. At the time of introduction, the oxidant 28 is added from the oxidant addition device 14. As the oxidant 28, sodium hypochlorite, hydrogen peroxide, potassium permanganate, ozone and the like are added. At this time, about 0.05 ppm to 5 ppm is added for chlorine. In the case of sodium hypochlorite, about 0.05 ppm to 5 ppm is added as residual chlorine. In the case of hydrogen peroxide, about 0.05 ppm to 50 ppm is added. In the case of ozone, about 0.05 ppm to 5 ppm is added.

When these oxidants 28 are irradiated with ultraviolet rays from the ultraviolet light source 23 in the accelerated oxidation tank, hydroxy radicals 29 (HO.) Having a strong oxidizing action are generated. Regarding the mechanism of generation of hydroxy radicals 29 when irradiated with ultraviolet rays, in the case of ozone,
O ₃ + hν → O ₂ + O ·
O ・ + H ₂ O → 2HO ・
O ₃ + H ₂ O + hν → HOOH + O ₂
HOOH + hν → 2HO ・
It is expressed by the reaction.

Regarding the mechanism of generation of hydroxy radicals 29 when irradiated with ultraviolet rays, in the case of chlorine,
Cl ₂ + H ₂ O → HClO + HCl
HClO + hν → HO · + Cl−
It is expressed by the reaction.

Regarding the mechanism of generation of hydroxy radicals 29 when irradiated with ultraviolet rays, in the case of hydrogen peroxide,
H ₂ O ₂ + hν → 2HO ·
It is expressed by the reaction.

The hydroxy radical 29 has an oxidation-reduction potential of +2.85 eV and has a strong oxidizing power comparable to that of fluorine. When a large amount of oxidant 28 is used and a large amount of hydroxy radicals 29 are generated by sufficient ultraviolet irradiation, most organic substances can be decomposed into H ₂ O and CO ₂ to be mineralized. By such an action, the organic matter is decomposed in the accelerated oxidation tank 15. At this time, aeration is performed in which the gas 27 is put into the accelerated oxidation tank 15 to generate bubbles. By this aeration, the hydroxy radicals 29 are diffused, and the decomposition of the organic matter in the accelerated oxidation tank 15 is further promoted. This mechanism will be described in detail later.

The treated water 13 in which the organic matter is finely decomposed in the accelerated oxidation tank 15 is introduced into the activated carbon treatment tank 16 at the subsequent stage. The activated carbon treatment tank 16 has an SV (empty speed) of 2 to 20. SV is a numerical value representing how many times the water per 1 m ³ of activated carbon is passed through per hour.

  For example, in the case of SV2, the contact time is doubled and 30 minutes. In the case of SV20, it becomes 20 minutes and 3 minutes. In the activated carbon treatment tank 16, the organic matter is adsorbed on the activated carbon 31. In addition, microorganisms 32 are grown on the activated carbon 31. The microorganisms 32 decompose organic substances trapped in the pores. As a result, the activated carbon 31 is regenerated and the lifetime of the activated carbon 31 tends to be longer than the calculated value.

  When ozone or the like is added in the accelerated oxidation tank 15, the hardly decomposable organic substance is reduced in molecular weight, and becomes an easily decomposable organic substance. In addition, dissolved oxygen in the water is sufficiently replenished by aeration. As a result, dissolved oxygen is sufficiently supplied to the microorganisms 32 growing in the activated carbon 31 in the activated carbon treatment tank 16, the activity of the microorganisms 32 is increased, and a large amount of captured organic matter is decomposed, so that the life of the activated carbon 31 is extended.

  Further, the activated carbon 31 has a function of acting as a catalyst for reducing the substance. That is, ozone is converted into oxygen, or sodium hypochlorite is decomposed into sodium chloride. Therefore, the oxidizing agent 28 brought from the accelerated oxidation tank 15 is detoxified by the catalytic reduction action of the activated carbon 31 in the activated carbon treatment tank 16. That is, the combination of the accelerated oxidation tank 15 and the activated carbon treatment tank 16 has an effect that the reduction treatment of the special oxidant 28 can be omitted.

  The treated water 13 from which almost all organic substances have been removed in the activated carbon treatment tank 16 is introduced into the subsequent RO membrane separation device 17. If the treated water 13 contains a large amount of humins, the humins adhere to the RO membrane 33 and cause clogging. In particular, recent synthetic organic membranes have a surface charge, and due to this surface potential relationship, colloidal substances such as fulvic acid are likely to adhere to the surface of the RO membrane 33, and contamination of the membrane that cannot be recovered by cleaning is likely to occur. Cause. However, in the water treatment apparatus of the present embodiment, the organic matter is sufficiently decomposed in the accelerated oxidation tank 15, and the organic substance is adsorbed and further decomposed in the activated carbon treatment tank 16 in the subsequent stage. As a result, the RO membrane 33 can have a long life and a large amount of water treatment.

  FIG. 2 is a front sectional view of accelerated oxidation tank 15 in the first embodiment of the present invention. In FIG. 2, the treated water 13 is introduced into the accelerated oxidation tank 15 from the lower inlet 21. Derivation from the accelerated oxidation tank 15 to the subsequent activated carbon treatment tank 16 is performed from the outlet 22 at the top of the accelerated oxidation tank 15. If the treated water 13 is gradually replaced from the bottom where the inlet 21 is located, the treated water 13 is set to be replaced in approximately 1 to 10 minutes.

  An oxidizer addition device 14 is installed in front of the inlet 21 of the accelerated oxidation tank 15. From the oxidant addition device 14, an oxidant 28 is added to the treated water 13 by a certain amount. As the oxidizing agent 28, ozone water, sodium hypochlorite, hydrogen peroxide, potassium permanganate and the like are added. If sufficient oxidant such as sodium hypochlorite remains in the pretreated filtered water, this apparatus may not be installed, and even if it is installed, the operation may be delayed.

A plurality of ultraviolet light sources 23 are suspended from the ceiling 15 b portion of the accelerated oxidation tank 15. The ultraviolet light source 23 has a substantially cylindrical shape with a glass surface, and has a diameter of about 15 mm to 70 mm and a length of about 300 mm to 2200 mm. That is, the ultraviolet light source 23 is installed in a shape that is long in the vertical direction. Ultraviolet light having a wavelength of 400 nm or less is emitted from the ultraviolet light source 23. Each ultraviolet lamp has a ramp output of ^{5W / m 3 / h~50W / m} 3 / h. When the ultraviolet rays are added to the ozone, which is the oxidizing agent 28, the oxidizing agent 28 generates hydroxy radicals 29. However, since the ultraviolet rays are attenuated immediately in water, the region where the hydroxy radicals 29 are present at a high concentration is limited to a narrow range of several centimeters near the surface of the ultraviolet light source 23 in the absence of aeration.

  A plurality of tubular diffuser tubes 24 each having an ejection hole 25 for the aeration gas 27 are installed on the bottom surface 15 a of the accelerated oxidation tank 15. A gas 27 mainly composed of air is constantly ejected from the ejection holes 25. The amount of air to be ejected is 5 NL / min to 25 NL / min. The structure of the ejection hole 25 is shown in FIG. 3A is a top view of the diffuser tube 24 provided with the ejection holes 25, FIG. 3B is a bottom view of the diffuser tube 24, and FIG. 3C is a cross-sectional view of the diffuser tube 24. FIG. The tubular air diffuser 24 has an ejection hole 25 on the bottom surface 15 a side of the accelerated oxidation tank 15. The diameter of the ejection hole 25 is 2 mm to 6 mm. As shown in FIG. 3, the ejection hole 25 is not directly below, but is slightly shifted to the left or right from the center. The left and right sides are staggered. By doing in this way, bubbles are stably supplied over a wide range.

  The ejected gas 27 rises in the treated water 13 as bubbles, and rises along the ultraviolet light source 23 in the vicinity of the side surface 23 a of the ultraviolet light source 23. A part of the ejection hole 25 is located directly below the ultraviolet light source 23 so that the gas 27 rises along the ultraviolet light source 23. The gas 27 emitted from the surface of the treated water 13 is discharged from the gas discharge port 30.

  By the movement of the bubbles of the gas 27, the treated water 13 and the hydroxy radicals 29 near the surface of the ultraviolet light source 23 are stirred and diffused. That is, the hydroxy radicals 29 generated by the ultraviolet rays and the oxidizing agent 28 diffuse into the accelerated oxidation tank 15. On the other hand, water containing the unreacted oxidant 28 is replaced in the vicinity of the ultraviolet light source 23. Therefore, the treated water 13 that has not yet been promoted to oxidation approaches the vicinity of the ultraviolet light source 23, and is sufficiently irradiated with ultraviolet rays to promote hydroxyl radicalization. Then, the hydroxyl radicals 29 diffused in the accelerated oxidation tank 15 by aeration can secure a sufficient reaction time with organic substances in water. That is, accelerated oxidation is performed over a wide range, and decomposition of organic substances is promoted over a wide range. Such a process is repeated, so that more treated water 13 is accelerated and oxidized, and organic matter is decomposed.

  In the present embodiment, the ultraviolet light source 23 is suspended vertically, and the longitudinal direction of the ultraviolet light source 23 is installed in the vertical direction. With this arrangement, when the bubble rises along the side surface 23a of the ultraviolet light source 23, the route of the bubble is not disturbed by the ultraviolet light source 23, so that the bubble rises at a high speed. The diffusion of the treated water 13 is increased by the air lift effect due to the movement of the bubbles, and the accelerated oxidation becomes more efficient.

  Further, since the gas 27 moves along the side surface 23a of the ultraviolet light source 23, the bubbles do not hit the side surface 23a strongly, so that the ultraviolet light source 23 is not broken and damaged.

  At this time, if an aeration gas 27 mixed with ozone is used, a better effect can be obtained. Ozone is an oxidizing agent 28 and generates hydroxy radicals 29 when irradiated with ultraviolet rays. In this accelerated oxidation tank 15, the aeration gas 27 passes in the vicinity of the ultraviolet light source 23, and thus generates hydroxy radicals 29. This decomposes organic matter with a strong oxidizing power.

  Furthermore, a good effect on the subsequent activated carbon treatment tank 16 by aeration is also produced. Usually, air is used for aeration. Air contains oxygen. This oxygen is partially dissolved in the treated water 13 by aeration. The dissolved oxygen is sent to the activated carbon treatment tank 16 at the next stage. Microbes 32 exist in the activated carbon treatment tank 16. If there is sufficient dissolved oxygen in the treated water 13, the activity of the microorganisms 32 in the activated carbon treatment tank 16 is also increased. As the activity of the microorganism 32 increases, the decomposition of the organic matter becomes more active, and the purification efficiency is improved.

  In addition, aeration cannot be installed in the activated carbon treatment tank 16 in order to melt oxygen and activate the microorganisms 32. This is because when the treated water 13 is stirred, the entire activated carbon 31 is contaminated. In other words, if sufficient oxygen is to be supplied to the activated carbon treatment tank 16, oxygen must be supplied at the front stage of the activated carbon treatment tank 16 as in the present embodiment. In the present embodiment, the presence of aeration in the front stage of the activated carbon treatment tank 16 synergistically gives a good effect to the subsequent stage of the activated carbon treatment tank 16.

Also when ozone is used as the oxidant 28, as described above, a good effect on the activated carbon treatment tank 16 is produced. As mentioned earlier, the chemical reaction when ozone is added is
O ₃ + hν → O ₂ + O ·
O ・ + H ₂ O → 2HO ・
O ₃ + H ₂ O + hν → HOOH + O ₂
HOOH + hν → 2HO ・
As a result, oxygen is generated. This oxygen is added to the treated water 13 and is sent to the subsequent activated carbon treatment tank 16 to activate the microorganisms 32 and improve the treatment efficiency of organic matter.

  Although the sand filtration tank 12 is in the front stage of the accelerated oxidation tank 15, the solid water suspended in the sand filtration tank 12 is removed and the transparency is increased, so that the ultraviolet rays in the subsequent accelerated oxidation tank 15 are increased. It has the effect of increasing the reach distance.

  In the first embodiment, the aeration ejection hole 25 is located directly below the ultraviolet light source 23, but the purpose is to move the treated water 13 near the surface of the ultraviolet light source 23 by aeration. When the ultraviolet light source 23 is thick, it is preferable to arrange the ejection hole 25 not directly below the side surface 23a of the ultraviolet light source 23, but directly below it. By causing bubbles to run up near the side surface 23a at a high speed, the effect of strongly stirring the treated water 13 and diffusing the water is increased.

  The gas 27 introduced into the accelerated oxidation tank 15 by aeration has to be finally exhausted from the accelerated oxidation tank 15, but is actually mixed with the treated water 13 near the surface of the treated water 13 and becomes a foam state. Yes. FIG. 4 is a top cross-sectional view of accelerated oxidation tank 15 in the first embodiment of the present invention. It is sectional drawing of the vicinity of the outlet 22 especially near the ceiling 15b. From the outlet 22 on the wall surface 15c, which is the side surface of the accelerated oxidation tank 15 near the ceiling 15b, the treated water 13 mixed with bubbles is led to the activated carbon treatment tank 16 at the subsequent stage. Generally, the outlet 22 is connected to the wall surface 15c at a right angle. However, in Embodiment 1 of the present invention, the outlet 22 is not connected to the wall surface 15c of the accelerated oxidation tank 15 at a right angle but is connected obliquely. Therefore, an inclined flow 35 is generated in the derived treated water 13 with respect to the wall surface 15 c of the accelerated oxidation tank 15. Due to this flow 35, a vortex 36 is generated in the foam-mixed treated water 13 collected near the ceiling 15b, and the treated water 13 near the ceiling 15b is sequentially led out. Accordingly, there is an effect of preventing a part of the treated water 13 from staying in the accelerated oxidation tank 15 for an abnormally long time. At the same time, the gas 27 is discharged as bubbles. The oblique angle of the center line of the outlet 22 to be connected is preferably as close to the tangential direction as possible with respect to the wall surface 15c of the cylindrical accelerated oxidation tank 15.

(Embodiment 2)
FIG. 5 is a front cross-sectional view of accelerated oxidation tank 15 in the second embodiment of the present invention. In FIG. 5, components having the same functions as those in FIG. The treated water 13 is introduced into the accelerated oxidation tank 15 from the lower inlet 21. Derivation from the accelerated oxidation tank 15 to the subsequent activated carbon treatment tank 16 is performed from the outlet 22 at the top of the accelerated oxidation tank 15.

  An oxidizer addition device 14 is installed in front of the inlet 21 of the accelerated oxidation tank 15. An oxidant 28 is added to the treated water 13 from the oxidant addition device 14. A plurality of ultraviolet light sources 23 are suspended from the ceiling 15 b portion of the accelerated oxidation tank 15. The ultraviolet light source 23 has a substantially cylindrical shape with a glass surface, and has a diameter of about 15 mm to 70 mm and a length of about 300 mm to 2200 mm. The difference from the configuration of FIG. 2 is that the ultraviolet light source 23 is installed in a shape that is long in the horizontal direction. In FIG. 5, the ultraviolet light source 23 has a shape that is long in the direction perpendicular to the paper surface.

  A plurality of diffuser tubes 24 each having an ejection hole 25 for the aeration gas 27 are installed on the bottom surface 15 a of the accelerated oxidation tank 15. In FIG. 5, as in FIG. 2, the air diffuser 24 extends long in the direction perpendicular to the paper surface. As shown in FIG. 5, the air diffuser 24 and the ultraviolet light source 23 are substantially parallel, and the air diffuser 24 is located directly below the ultraviolet light source 23.

  A gas 27 mainly composed of air is ejected from the ejection hole 25. The ejected gas 27 rises in the treated water 13 as bubbles, and many bubbles hit the side surface 23 a of the ultraviolet light source 23. Therefore, the bubbles of the gas 27 are diffused and spread over the entire treated water 13 above the ultraviolet light source 23 (gas 27a). By the movement of the bubbles, the hydroxy radicals 29 generated near the surface of the ultraviolet light source 23 are stirred and spread to the entire treated water 13 above the ultraviolet light source 23 (hydroxy radical 29a). That is, the hydroxyl radical 29 is diffused into the accelerating oxidation tank 15 by the ultraviolet ray and the oxidant 28 and is accelerated and oxidized by the activated oxidant 28. That is, accelerated oxidation is performed over a wide range, and decomposition of organic substances is promoted over a wide range.

(Embodiment 3)
The aeration gas 27 generated in the accelerated oxidation tank 15 is discharged from the gas discharge port 30. However, the surface of the treated water 13 is foamed by aeration, and the treated water 13 containing the foam is sent from the outlet port 22 to the activated carbon treatment tank 16 at the subsequent stage. That is, the gas 27 is also sent to the subsequent activated carbon treatment tank 16 together with the treated water 13. Therefore, the activated carbon treatment tank 16 also needs to be exhausted. FIG. 6A is a front sectional view of the upper part of the activated carbon treatment tank 16. The treated water 13 a in the activated carbon treatment tank 16 has a water level above the activated carbon 31, and the liquid level 13 b is about to reach the ceiling of the activated carbon treatment tank 16. There is an exhaust port 40 on the ceiling, and a spherical float 42 floats on the liquid surface 13b of the treated water 13a just below it. The spherical float 42 floats on the treated water 13a and moves up and down along the center line 42c. When the water level is low, the float 42 is separated from the exhaust port 40, and the gas 27 is discharged from the exhaust port 40. When the water level becomes higher, the float 42 comes into contact with the exhaust port 40 and closes the port, so that neither the gas 27 nor the treated water 13a is released. By this, only the gas 27 is discharged | emitted from the activated carbon processing tank 16, and it can prevent that the treated water 13a spills out. The float 42 functions as an exhaust valve. The above is a simple example using a float, but there are actually many more complicated structures using a float. In principle, the mechanism of closing the exhaust valve when the float floats is the same.

(Embodiment 4)
Another embodiment of exhaust from the activated carbon treatment tank 16 will be described. FIG. 6B is a front sectional view of the upper part of the activated carbon treatment tank 16. The embodiment shown in FIG. 6B is different from the embodiment shown in FIG. 6A in that a liquid level gauge 44 and an exhaust valve 43 are installed in place of the float 42. When the water level is low, the liquid level gauge 44 detects it and opens the exhaust valve 43. When the water level becomes higher, the liquid level gauge 44 detects it and closes the exhaust valve 43. By this control, only the gas 27 can be released from the activated carbon treatment tank 16 and the treated water 13 can be prevented from spilling out.

(Embodiment 5)
Another embodiment of the method for treating the treated water 13 introduced into the activated carbon treatment tank 16 will be described. FIG. 7 is a configuration block diagram of the entire water treatment device according to Embodiment 5 of the present invention. The configuration is basically the same as that of the first embodiment described with reference to FIG. The difference from the first embodiment is that a discharge pipe 41 is provided at the upper part of the activated carbon treatment tank 16, the surface layer of the treated water 13 in the activated carbon treatment tank 16 is discharged, and it is returned to the sand filtration tank 12. . The treated water 13 sent from the accelerated oxidation tank 15 to the activated carbon treatment tank 16 contains many bubbles by aeration. Accordingly, the treated water 13 in the activated carbon treatment tank 16 has a foamed surface layer from the surface to a depth of about 10 cm. By removing the surface layer of the treated water 13, foaming in the activated carbon treatment tank 16 is reduced, and adverse effects due to foam on the activated carbon 31 are eliminated. Moreover, since the treated water 13 discharged from the activated carbon treatment tank 16 is returned to the sand filtration tank 12 again, it is not discharged to the outside and does not cause environmental pollution.

(Embodiment 6)
Still another embodiment of the method for treating the treated water 13 introduced into the activated carbon treatment tank 16 will be described. FIG. 8 is a configuration block diagram of the entire water treatment device according to Embodiment 6 of the present invention. The configuration is basically the same as that of the first embodiment described with reference to FIG. The difference from the first embodiment is that a tank 45 for separating liquid and gas is provided at the subsequent stage of the activated oxidation tank 15 and at the previous stage of the activated carbon treatment tank 16. The treated water 13 sent from the accelerated oxidation tank 15 to the activated carbon treatment tank 16 contains many bubbles by aeration. In the tank 45, the treated water 13 is allowed to stay in the tank 45 for 5 to 30 minutes before being sent to the subsequent activated carbon treatment tank 16. During this residence time, the bubbles in the treated water 13 are separated into liquid and gas, and the bubbles disappear. The separated gas 27 is discharged from the upper part of the tank 45 to the outside.

(Embodiment 7)
FIG. 9 is a configuration block diagram of the entire water treatment device according to Embodiment 7 of the present invention. The configuration is basically the same as that of the first embodiment described with reference to FIG. The difference from Embodiment 1 is that an MF membrane separation device 46 that separates solid impurities by a microfilter membrane (MF membrane) 47 is provided in the subsequent stage of the activated carbon treatment tank 16 and in the previous stage of the RO membrane separation device 17. is there. The MF membrane 47 is a filtration membrane having a pore size of 0.01 μm to 10 μm, also called a microfiltration membrane. Solid impurities are filtered in the sand filtration tank 12, but only solids having a size of about 1 μm or more can be filtered. By passing the treated water 13 through the MF membrane separation device 46 having the MF membrane 47, solid matter of 1 μm or less can be filtered, and the burden on the RO membrane 33 in the subsequent stage can be reduced. At the same time, fine particles generated in the activated carbon treatment tank 16 and flowing into the treated water 13 for the subsequent process can also be removed by the MF film 47, thereby reducing the burden on the subsequent RO film 33. Can do.

  Instead of the MF membrane separation device 46, a UF membrane separation device using a UF membrane may be used. The UF membrane is a filtration membrane having a pore diameter of 2 nm to 200 nm, also called an ultrafiltration membrane or an ultrafiltration membrane. Regardless of whether the MF membrane or the UF membrane is used, fine solids that could not be removed by sand filtration are removed, and fine particles flowing out to the activated carbon treatment tank 16 are removed at the same time. The effect of reducing is the same.

(Embodiment 8)
FIG. 10 is a configuration block diagram of the entire water treatment device according to the eighth embodiment of the present invention. In this embodiment, organic waste water is used as raw water 11 and treated water 13 is recovered as pure water production or industrial water using an RO membrane. A significant difference from the above-described embodiment is that a biological treatment tank 48 is provided in front of the sand filtration tank 12. Further, as in the seventh embodiment, an MF membrane separation device 46 that separates solid impurities by a microfilter membrane (MF membrane) 47 is provided in the subsequent stage of the activated carbon treatment tank 16 and in the previous stage of the RO membrane separation apparatus 17. It is. The biological treatment tank 48 purifies organic wastewater by utilizing activated sludge, floating microorganisms such as nitrifying bacteria and denitrifying bacteria, and oxidative decomposition and absorption separation of various organic substances. In this way, by using the biological treatment tank 48, even if the raw water 11 is an organic wastewater containing a hardly decomposable organic substance such as a surfactant, the treatment method described in the first to seventh embodiments is utilized. Water purification.

  At this time, if the amount of organic matter contained in the treated water 13 is very large, the propagation of the microorganism 32 in the accelerated oxidation tank 15 and the activated carbon treatment tank 16 becomes active, and there is a concern that the treated water 13 may flow out. In that case, it is effective to provide the MF membrane separation device 46 in the subsequent stage of the activated carbon treatment tank 16. It is filtered by the MF membrane 47 of the MF membrane separator 46 and removed from the treated water 13.

  The same effect can be obtained by using a UF membrane separation device using a UF membrane instead of the MF membrane separation device 46 using the MF membrane 47 described above.

(Embodiment 9)
FIG. 11 is a configuration block diagram of the entire water treatment device according to Embodiment 9 of the present invention. In this embodiment, organic waste water is used as raw water 11, and treated water 13 is collected as pure water production or industrial water using an RO membrane. The configuration is very similar to that of the eighth embodiment. The difference from the eighth embodiment is that the MF membrane separation device 46 does not exist in the subsequent stage of the activated carbon treatment tank 16, and instead, the MF membrane separation having the MF membrane 47 between the biological treatment tank 48 and the accelerated oxidation tank 15. The device 46 is interposed. Further, the treated water 13 led out from the activated carbon treatment tank 16 is switched to either the RO membrane separation device 17 or the discharge pipe 41 by the switching valve 50 and is sent. The treated water 13 sent to the discharge pipe 41 is temporarily stored in the tank 49 and then returned to the MF membrane separation device 46.

  When the organic waste water contains a high concentration of organic matter, the biological treatment tank 48 uses a fluid carrier method, an activated sludge treatment method, or a combination method of both. In this case, a pressure-type or submerged membrane filtration is used for solid-liquid separation, and the precipitation separation tank and the sand filter can be omitted. By the purification of the MF film 47, the transparency of the treated water 13 is increased, and the treatment in the subsequent accelerated oxidation tank 15 becomes more efficient.

  The treated water 13 treated in the accelerated oxidation tank 15 is then purified in the activated carbon treatment tank 16. Thereafter, when the degree of pollution of the organic waste water is small, the switching valve 50 sends the treated water 13 to the RO membrane separator 17 for the treated water 13 coming out of the activated carbon treatment tank 16. The treated water 13 that has been sent is purified by the RO membrane separation device 17, becomes purified water 18, and is sent from the water treatment device.

  After the treatment in the activated carbon treatment tank 16, when the degree of purification of the treated water 13 is not yet sufficient, the switching valve 50 sends the treated water 13 to the discharge pipe 41. The treated water 13 sent to the discharge pipe 41 is temporarily stored in the tank 49. Thereafter, it is returned to the MF membrane separator 46. Thus, the treated water 13 is further purified by passing through the MF membrane separation device 46, the accelerated oxidation tank 15, and the activated carbon treatment tank 16 again. Thereafter, the treated water 13 is fed to the RO membrane separation device 17 by switching the switching valve 50. The water that has passed through the RO membrane separation device 17 is taken out from the water treatment device as purified water 18. By performing the process of returning the treated water 13 to the MF membrane separation device 46 again, even when there is no inflow of wastewater, the treated water 13 is circulated without stopping the device, and the AOP treatment is performed more efficiently. Water treatment becomes possible.

  The same effect can be obtained by using a UF membrane separation device using a UF membrane instead of the MF membrane separation device 46 using the MF membrane 47 described above.

  The water treatment apparatus of the present invention uses RO membranes from organic wastewater treated water containing high-colored groundwater or surfactants due to humic substances, when recovering to pure water production or industrial water, The RO membrane can be efficiently produced without causing clogging, and is useful.

The block diagram of the water treatment apparatus in Embodiment 1 of this invention Front sectional drawing of the promotion oxidation tank in Embodiment 1 of this invention Structure diagram of air diffuser in embodiment 1 of the present invention Cross-sectional top view of the accelerated oxidation tank in the first embodiment of the present invention Front sectional view of the accelerated oxidation tank in Embodiment 2 of the present invention Front sectional view of the activated carbon treatment tank in Embodiments 3 and 4 of the present invention The block diagram of the water treatment apparatus in Embodiment 5 of this invention The block diagram of the water treatment apparatus in Embodiment 6 of this invention The block diagram of the water treatment apparatus in Embodiment 7 of this invention The block diagram of the water treatment apparatus in Embodiment 8 of this invention The block diagram of the water treatment apparatus in Embodiment 9 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Raw water 12 Sand filtration tank 13,13a Treated water 13b Liquid surface 14,14a Oxidant addition apparatus 15 Promotion oxidation tank 15a Bottom surface 15b Ceiling 15c Wall surface 16 Activated carbon treatment tank 17 RO membrane separator 18 Purified water 21 Inlet 22 Outlet 23 Ultraviolet light source 23a Side surface 24 Diffuser tube 25 Ejection hole 27, 27a Gas 28 Oxidant 29, 29a Hydroxyl radical 31 Activated carbon 32 Microorganism 33 RO membrane 36 Eddy current 37 Sand 38 Gravel 40 Exhaust port 41 Exhaust pipe 42 Float 42c Center line 43 Exhaust valve 43 44 Liquid level gauge 45 Tank 46 MF membrane separator 47 MF membrane 48 Biological treatment tank 49 Tank 50 Switching valve

Claims (27)

A water treatment apparatus having an accelerated oxidation tank for aeration in treated water in the vicinity of an ultraviolet light source. The water treatment apparatus according to claim 1, wherein ozone is added as an oxidant to the treated water in the accelerated oxidation tank. The water treatment apparatus according to claim 1, wherein at least one of chlorine, sodium hypochlorite, and hydrogen peroxide is added as an oxidant to the treated water in the accelerated oxidation tank. The water treatment apparatus according to claim 1, wherein the gas used for the aeration includes ozone. The water treatment apparatus according to claim 1, wherein an activated carbon treatment tank is provided downstream of the accelerated oxidation tank. The water treatment device according to claim 5 which has microorganisms in activated carbon of said activated carbon treatment tank. The water treatment apparatus according to claim 5 or 6, wherein the oxidizing agent added in the accelerated oxidation tank is subjected to a reduction treatment in the activated carbon treatment tank. The water treatment apparatus according to claim 7, wherein an RO membrane separation device is provided downstream of the activated carbon treatment tank. The water treatment device according to claim 8, wherein an MF membrane separation device or a UF membrane separation device is provided downstream of the activated carbon treatment tank and upstream of the RO membrane separation device. The water treatment apparatus of Claim 5 or Claim 8 which provided the sand filtration tank in the front | former stage of the said accelerated oxidation tank. The water treatment apparatus according to claim 1, wherein the ultraviolet light source has a shape that is long in a vertical direction. The water treatment apparatus according to claim 1 or 11, wherein the ultraviolet light source is suspended from above. The water treatment apparatus according to claim 1, wherein the ultraviolet light source has a shape that is long in a horizontal direction. The water treatment apparatus according to claim 1, wherein the aeration gas passes near the surface of the ultraviolet light source. The water treatment apparatus according to any one of claims 1, 11, and 13, wherein the ejection hole for aeration is located directly below the ultraviolet light source. The water treatment apparatus according to claim 11 or 13, wherein the ejection hole for aeration is located directly below a side surface of the ultraviolet light source. The water treatment apparatus according to claim 13, wherein an air diffuser having the aeration ejection holes and the ultraviolet light source are parallel to each other. The water treatment apparatus according to claim 1, wherein the accelerated oxidation tank has a cylindrical wall surface as a side surface, a discharge port for discharging treated water, and the discharge port is attached obliquely to the wall surface. . The water treatment apparatus according to claim 5, wherein the activated carbon treatment tank has an exhaust valve. The water treatment device according to claim 10, wherein the activated carbon treatment tank returns the surface layer of the treated water to the sand filtration tank. The water treatment apparatus according to claim 5, wherein a tank that retains treated water is provided in a stage subsequent to the activated oxidation tank and in a stage preceding the activated carbon treatment tank. The water treatment apparatus according to claim 1, wherein the treated water is groundwater containing humins and organic wastewater. The water treatment apparatus according to claim 22, wherein an activated carbon treatment tank is provided downstream of the accelerated oxidation tank. The water treatment device according to claim 23, wherein an MF membrane separation device or a UF membrane separation device is provided at a subsequent stage of the activated carbon treatment tank. The water treatment apparatus according to claim 22, wherein an MF membrane separation device or a UF membrane separation device is provided upstream of the accelerated oxidation tank. 26. The water treatment apparatus according to claim 25, wherein an activated carbon treatment tank is provided downstream of the accelerated oxidation tank, and waste water from the activated carbon treatment tank is returned to the MF membrane separation apparatus or the UF membrane separation apparatus. 27. The water treatment device according to any one of claims 24 to 26, wherein microorganisms are present on a membrane surface of the MF membrane separation device or the UF membrane separation device.

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