JP2009254967A - Water treatment system - Google Patents

Abstract

In a water treatment system that removes organic matter using ozone treatment and biological treatment, a highly economical water treatment system having high organic matter removal performance is provided by improving the efficiency of ozone treatment.
Ozone microbubbles generated in water to be treated by a microbubble generator 1A are injected into an ozone reaction tank 11A. This water to be treated is treated with a biofilm formed on the biological activated carbon layer 23 of the biological reaction tank 21A to further decompose and adsorb organic matter. Since ozone microbubbles have high oxidative power and reactivity, they can efficiently decompose organic substances and can also denature biologically difficult-to-decompose organic substances into biodegradable organic substances. Moreover, since the reactivity is high, the dissolved ozone density | concentration after a process is reduced and the soundness of the microorganisms of the biological and activated carbon treatment tank 21A can be maintained. As a result, the organic matter removal efficiency and the maintainability in the water to be treated are improved, and the economics of water treatment is improved.
[Selection] Figure 1

Description

  The present invention relates to a water treatment system using microbubbles suitable for removing organic substances such as sewage, river water, lake water, and industrial wastewater.

  When sewage treatment water is discharged into lakes and marshes due to topographical constraints, it is necessary to improve the quality of the discharged water from the viewpoint of water quality conservation and environmental protection. In particular, when the discharge destination lakes and the like form a closed water area, it is necessary to reduce the organic matter in the discharge water in consideration of the impact on the ecosystem. Environmental Standard No. 59 (“Environmental Standards Related to Water Pollution”, December 28, 1971) shows environmental standards related to water pollution targeting lakes and marshes. The standard items include chemical oxygen demand (COD), and 1 mg / L is suggested as the COD standard value for lakes where water products such as water supply of grade 1 and water products such as Japanese black trout grow. Yes.

As an effort to reduce organic matter in the entire lake, [Non-Patent Document 1] describes a technique for ultra-high-level treatment of sewage treated water. The water treatment facility described in Non-Patent Document 1 is a method of water treatment (hereinafter referred to as “ozone, biological / activated carbon treatment”) that combines ozone treatment and biological / activated carbon treatment, which is a kind of biological treatment, This is a demonstration facility where the COD target value of the discharged water is set to 3 mg / L. In the ozone treatment of water containing organic matter, COD components are decomposed according to the ozone injection rate, and biodegradable biochemical oxygen demand (BOD) components and biodegradable COD components are separated. Generate.
In the biological / activated carbon treatment, microorganisms attached to the activated carbon mainly decompose the BOD component, and the activated carbon adsorbs the remaining BOD component and COD component.

  [Non-Patent Document 2] includes ozone injection efficiency improvement, life extension of biological activated carbon, and reduction of treatment costs as problems of ozone and biological / active carbon treatment methods.

  As a conventional technique of a water treatment (hereinafter referred to as “ozone, biological treatment”) that combines ozone treatment and biological treatment similar to the above, [Patent Document 1] includes an ozone injection device, an ultraviolet irradiation device, and a biological treatment. A technique is described which comprises a filtering means, dissolves ozone gas in water to be treated and irradiates ultraviolet rays, and then performs biological filtration. In addition, the ozone injection amount and the ultraviolet irradiation amount are limited, the BOD component is increased, and the biological filtration means decomposes. According to this technique, it is described that dissolved ozone after ozone treatment is decomposed by ultraviolet rays, and the load caused by ozone oxidation of the biological filtration means is reduced.

  [Patent Document 2] provides a bubble tower between ozone treatment and biological treatment, and purifies air into ozone treated water in which ozone gas is dissolved in water to be treated, and then performs an advanced treatment method for wastewater to perform biological treatment. And the device technology is described. According to this technique, it is described that the concentration of dissolved ozone after ozone treatment is reduced by air purge to reduce the load caused by ozone oxidation of the biofilm filtration means.

  In [Patent Document 3], in the ozone and biological treatment system, a part of treated water after biological treatment is extracted, added to the treated water for ozone treatment, and purified for water to be circulated between ozone treatment and biological treatment. A processing method is described. According to this technique, it is described that the contact time per volume of water to be treated is increased and the COD component removal performance is improved.

  In [Non-patent Document 2], a microbubble is a bubble having a diameter of 50 micrometers or less, and in general, a bubble of this size shrinks in liquid due to the dissolution of the gas in the bubble into the surrounding fluid.・ It can be completely dissolved in about 2 minutes. Since the diameter of microbubbles decreases as it dissolves into the surrounding liquid, the inside becomes high temperature and high pressure due to the effect of surface tension. Microbubbles have a large surface area ratio to volume. Therefore, the dissolution efficiency is increased, and the dissolution is further promoted by Henry's law in which the solubility increases in proportion to the pressure of the gas. Microbubbles generate radicals having bactericidal power when extinguished. Since organic substances can be decomposed, it is described that purification, disinfection and disinfection effects can be obtained.

  [Non-patent Document 3] describes that ozone water in which gaseous ozone is dissolved has a high oxidation-reduction potential and has a strong sterilizing effect. If microbubbles are used for the production of ozone water, the dissolution rate is high. In other words, it is described that ozone gas desorbed upward from the liquid level is reduced and the utilization efficiency of ozone is improved. Hereinafter, microbubbles are defined in this way.

Furthermore, [Non-Patent Document 4] and [Non-Patent Document 5] describe that in the water treatment experiment conducted by the inventor, the dissolution efficiency and reaction efficiency of ozone microbubbles are high, and the water treatment performance is high. Has been.
JP 11-33592 A JP-A-9-29285 JP-A-5-104094 Shiga Prefecture 2006 Environmental White Paper, March 2007 “Characteristics of Water and New Utilization Technology”, NTS, pp. 142-146, May 17, 2004 "New Technology for Using Ozone", Sanyu Shobo, p. 74-83, 1988 Proceedings of the 43rd Sewerage Research Presentation, Japan Sewerage Association, pp. 821-823, June 26, 2006 44th Sewerage Research Presentation Lecture, Japan Sewerage Association, 733-735, June 29, 2007

In the prior art described in [Patent Document 1], an ultraviolet irradiation device stage is required in addition to the ozone injection device and the biological filtration means, and the equipment cost and the operation cost increase. Further, by limiting the ozone injection amount and the ultraviolet irradiation amount, there is a possibility that the decomposition performance of the COD component is lowered.
In the prior art described in [Patent Document 2], it is necessary to install a bubble column, a blower, and the like for air purge, which may increase the equipment cost and the operating cost.
In the prior art described in [Patent Document 3], a part of the treated water after biological treatment is returned to the ozone treatment tank, so that the treatment capacity is reduced for the equipment scale, so that the operating cost can be increased. There is sex.

  In view of the above problems, an object of the present invention is to improve the efficiency of ozone treatment in a water treatment method that removes organic matter using ozone treatment and biological treatment, thereby providing highly economical water with high organic matter removal performance. To provide a processing system.

  In order to achieve the above object, a water treatment system of the present invention includes an ozone generator that generates ozone gas, a microbubble generator that generates microbubbles using ozone gas generated by the ozone generator as a gas source, and a microbubble generator. An ozone reaction tank that injects ozone microbubbles generated by the treatment water into the treated water and oxidizes the treated water, and an organic biological treatment device that is provided downstream of the ozone reaction tank. After decomposing the organic matter in the treated water using ozone microbubbles, the biodegradable organic matter that has not been decomposed in the ozone reaction tank and the organic matter that has been modified to be biodegradable by ozone microbubbles It is characterized by biological treatment.

  Since the ozone reaction tank is oxidatively decomposed with water to be treated containing ozone microbubbles, the dissolution efficiency of ozone in the water to be treated is high, and organic substances in the water to be treated are efficiently denatured into biodegradable BOD components. . And the dissolved ozone concentration after ozone treatment falls. The BOD component in the ozone-treated water led to the biological treatment device provided at the latter stage of the ozone reaction tank is decomposed by the biological treatment device, but the dissolved ozone concentration is low, so the dissolved ozone concentration is high as before The organic substance decomposition performance in the biological treatment apparatus is improved.

  According to the present invention, in a water treatment system that removes organic matter using ozone treatment and biological treatment, an economical water treatment system having high organic matter removal performance is provided by improving the efficiency of ozone treatment. Can do.

<< First Embodiment >>
Hereinafter, a water treatment system according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing a configuration of a water treatment system according to the first embodiment.
As shown in FIG. 1, the water treatment system 100A of the present embodiment includes a microbubble generator 1A including a circulation channel 30 of water to be treated that mainly generates microbubbles, an ozone reaction tank 11A, a biological / activated carbon treatment tank. (Biological reaction tank) 21A. The ozone reaction tank 11 </ b> A and the biological treatment / active carbon treatment tank 21 </ b> A as a biological treatment apparatus are communicated with each other through an ozone treated water outflow path 32.

(Microbubble generator)
The microbubble generator 1A includes an ozone generator 2 that generates ozone gas, a flow rate adjustment valve 61 that controls the flow rate of the generated ozone gas, an ozone gas mixer 3 that mixes ozone gas into the water to be treated, and an ozone gas mixer 3 A pump 4 disposed on the downstream side of the pump 4 for boosting and discharging the water to be treated; a steam-water separator 5 disposed on the discharge side of the pump 4; and a downstream-side nozzle (pressure reducing device) of the steam-water separator 5 ) 6, a flow rate adjusting valve 62 disposed upstream of the ozone gas mixing device 3 to adjust the pump inlet pressure, the circulation flow path 30, the ozone generator 2, the flow rate adjusting valve 61, and the ozone gas mixing device 3 And an ozone gas injection pipe 63 connecting the two.

Here, a gas-liquid mixing system such as an ejector type, a diffuser system, and direct mixing is applied to the ozone gas mixing device 3.
The air / water separator 5 has a tank structure and is provided with an air vent (not shown) at the top, and the bubbles that have not dissolved in the water to be treated out of the ozone gas mixed by the ozone gas mixer 3 are placed above the air / water separator 5. And collected from the air vent to a buffer tank (not shown) by piping. The buffer tank described above is provided with a pressure reducing valve (not shown) and a pipe connected thereto, and the pipe is connected to an ozone gas injection pipe 63 connected to the ozone gas mixing device 3.
In addition, another pipe is branched from a buffer tank (not shown), and this pipe is connected to a diffuser pipe (not shown) provided at the bottom of the ozone reaction tank 11A through a relief valve, so that undissolved ozone is removed from the diffuser pipe. You may make it discharge | release in the ozone reaction tank 11A.

The nozzle 6 depressurizes the water to be treated in which the pressurized ozone gas is dissolved, and generates microbubbles in the water to be treated.
The circulation flow path 30 is pumped from a water extraction pipe 8 that draws and extracts water to be treated in a first compartment (partition compartment) 11a, which will be described later, from the ozone reaction tank 11A through a flow rate adjustment valve 62 and the ozone gas mixing device 3. 4 is connected to an inlet pipe 7 that opens from the outlet of the pump 4 via the steam / water separator 5 and the nozzle 6 to the first compartment 11a of the ozone reaction tank 11A.
Incidentally, the pump 4 is driven at a predetermined rotational speed by electric power from an inverter (not shown).

  The microbubble generator 1A is provided with an ozone flow meter and an ozone gas concentration meter (not shown) that measure the flow rate of ozone gas discharged from the ozone generator 2. Further, a dissolved ozone concentration meter 12 to be described later is provided in the ozone reaction tank 11A. The rotational speed of the pump 4 by the inverter and the ozone discharge current of the ozone generator 2 may be adjusted manually from an operation panel (not shown), or the control device 10 including a microcomputer may be used. When the control device 10 is used, the rotation speed of a motor by an inverter (not shown) that drives the pump 4, the amount of ozone generated by adjusting the ozone discharge current in the ozone generator 2, and the opening of the flow rate adjustment valve 61 are controlled, and the ozone reaction The amount of dissolved ozone in the tank 11A is controlled.

  As described in Japanese Patent Application Laid-Open No. 2007-21393, the control device 10 controls the opening degree of the nozzle 6 and appropriately controls the ozone micro according to the flow rate flowing through the circulation flow path 30 and the discharge pressure of the pump 4. You may control so that a bubble is produced | generated. A pressure gauge is provided on the upstream side of the nozzle 6.

  Thus, the dissolved ozone amount in the ozone reaction tank 11A is measured by the dissolved ozone concentration meter 12 by manual or automatic control, and compared with the ozone concentration target value, the amount of ozone injected into the ozone reaction tank 11A is excessive. The shortage is calculated, and the dissolved ozone concentration is within a predetermined range (ozone concentration target value) so that the activated carbon and microorganisms in the biological / activated carbon layer 23 of the biological / activated carbon treatment tank 21A, which is the biological treatment apparatus in the subsequent stage, are not oxidized too much. Can be controlled. Therefore, it is possible to inject ozone microbubbles into the ozone reaction tank 11A, which are suitable for the amount of water to be treated supplied to the ozone reaction tank 11A and the concentration of organic substances in the water to be treated.

(Ozone reaction tank)
The ozone reaction tank 11A is divided into a plurality of partitions (partition partitions) 11a, 11b, 11c, and 11d by a plurality of partition plates 13. The partition plate 13 includes partition plates 13A and 13C having a communication path between the bottom of the ozone reaction tank 11A and a bottom plate connected to the bottom of the ozone reaction tank 11A, and a partition plate 13B that communicates with the treated water over the top. It is configured to be alternately arranged in the flow direction. The water to be treated introduced into the first compartment 11a of the ozone reaction tank 11A of the water treatment system 100A first flows from the communication path below the partition plate 13A to the next compartment 11b on the downstream side, and passes over the partition plate 13B. It repeats the operation | movement which flows into the following division 11c of a downstream side, and it flows in into the next biological and activated carbon treatment tank 21A through the ozone treated water outflow path 32 as to-be-treated water (also called ozone treated water) treated with ozone. It has become.

  Below the center of the water depth level of the wall of the ozone reaction tank 11A of the first compartment 11a, the microbubble generator 1A has a microbubble generator 1A for injecting water to be treated containing microbubbles of ozone into the first compartment 11a. The injection pipe 7 of the circulation channel 30 is open. Further, the water to be treated for mixing ozone is disposed below the position of the injection pipe 7 on the wall of the ozone reaction tank 11A of the first section 11a and above the bottom of the ozone reaction tank 11A. The extraction pipe 8 taken in is opened.

  The ozone reaction tank 11A is covered with a lid, and is provided with a waste ozone flow path 17 that guides ozone that is separated from the water to be treated and accumulates in the upper gas phase space of the ozone reaction tank 11A. It is connected to the device 19. The exhaust ozone treatment device 19 is a device for releasing exhaust ozone into the atmosphere by, for example, decomposing with a catalyst. A dissolved ozone concentration meter 12 is provided near the outlet from the ozone reaction tank 11A of the ozone-treated water (in the vicinity of the outlet of the section 11d in FIG. 1), and the dissolved ozone concentration of the ozone-treated water is measured. When the control device 10 controls the dissolved ozone concentration in the ozone reaction tank 11 </ b> A by automatic control, a signal indicating the dissolved ozone concentration from the dissolved ozone concentration meter 12 is transmitted to the control device 10. In the case of manual control, the measured dissolved ozone concentration is displayed on an operation panel surface not shown. The ozone discharge current of the ozone generator 2 can be adjusted by visually confirming this.

(Biological / activated carbon treatment tank)
The biological / activated carbon treatment tank 21A is obtained by fixing a biological / activated carbon layer 23 made of a surface of activated carbon or a microbe for water treatment adhered to the inside of the activated carbon in the water treatment tank. The treated water that has been introduced with ozone treated water from above and passed through the biological / activated carbon layer 23 downward is discharged from the treated water drainage channel 33.

Next, the generation of ozone microbubbles and the action in the ozone reaction tank 11A will be described.
The gas-liquid two-phase flow state ozone and the water to be treated that have passed through the ozone gas mixing device 3 are pressurized by the pump 4, and a part of the ozone gas is pressurized and dissolved in the water to be treated. Undissolved ozone gas bubbles contained in the pressurized water to be treated are separated by the steam separator 5. The water to be treated in which ozone is dissolved is depressurized by the nozzle 6, the ozone gas is foamed, and ozone microbubbles are generated. The generated ozone microbubbles are injected from the injection tube 7 into the ozone reaction tank 11A.

The ozone microbubbles injected into the ozone reaction tank 11A by the injection pipe 7 are further mixed with the water to be treated in the process of flowing from the first compartment 11a to the next compartment 11b, and further to the next compartments 11c and 11d. The COD component is decomposed into biodegradable BOD components by ozone microbubbles. The BOD component and the biodegradable COD component remaining without being decomposed accompany the ozone treated water, and flow into the biological / activated carbon treatment tank 21A through the ozone treated water outflow passage 32. During this process, dissolved ozone is consumed and reduced.
Exhaust ozone gas collected and separated from the treated water in the gas phase of the ozone reaction tank 11A passes through the exhaust ozone passage 17 and is returned to normal oxygen by, for example, a contact catalyst, and released into the atmosphere. Is done.

Note that the ozone microbubbles injected into the ozone reaction tank 11A have higher dissolution efficiency because the microbubbles have a larger surface area ratio relative to the volume, and the dissolution is further accelerated by Henry's law in which the solubility increases in proportion to the gas pressure. Microbubbles generate OH radicals having sterilizing power when extinguished, and bacteria and organic substances can be decomposed by the OH radicals. Therefore, the decomposition of organic substances into biodegradable BOD components in the ozone reaction tank 11A is possible. Consumed efficiently. In other words, in the ozone treatment in which the ozone microbubbles are injected, due to the high reactivity of the ozone microbubbles, the decomposition of organic matter in the water to be treated is promoted, the biodegradable COD component is reduced, and the BOD component is increased. . As a result, the organic matter decomposed by the biological treatment in the subsequent process increases.
In addition, since ozone microbubbles are injected into the ozone reaction tank 11A, the bubbles of ozone are unlikely to float on the surface and remain in the treated water of the ozone reaction tank 11A for a long time.

  Due to the high reactivity of the ozone microbubbles, the dissolved ozone concentration of the ozone treated water flowing from the ozone reaction tank 11A into the biological / activated carbon treatment tank 21A decreases, so the same ozone as in the prior art that does not employ ozone microbubble injection Compared with the dissolved ozone concentration at the time of being injected into the ozone reaction tank in the case of the dissolved ozone concentration near the discharge port of the reaction tank, the ozone injection concentration in the ozone reaction tank 11A can be increased. This further reduces the biodegradable COD component.

Moreover, the rotation speed of the ozone generator 2 and the pump 4 so as to suppress the dissolved ozone concentration provided near the discharge port of the ozone reaction tank 11A to a predetermined value or less by manual control or automatic control by the control device 10. Since the opening degree of the nozzle 6 and the like are controlled, the dissolved ozone concentration is easily adjusted so that no load is imposed on the oxidation of activated carbon and the activity of microorganisms in the biological / active carbon treatment tank 21A on the downstream side.
As a result, it is not necessary to provide an ultraviolet irradiation device for reducing the dissolved ozone concentration in the ozone treated water outflow passage 32 as in the prior art.

Next, the operation in the biological / activated carbon treatment tank 21A will be described.
The organism / activated carbon layer 23 is installed in the organism / activated carbon treatment tank 21A, and the BOD component in the water to be treated (ozone treated water) is decomposed by the microorganisms attached to the activated carbon. In addition, the undegraded BOD component and the above-described biodegradable COD component are adsorbed and removed by the activated carbon.
Since the BOD component in the ozone-treated water introduced into the biological / activated carbon treatment tank 21A increases, the organic matter decomposed by the biological treatment increases, and the BOD component is efficiently decomposed into water, CO _{2 and the} like by the microorganisms. -Organic matter in the treated water discharged from the activated carbon treatment tank 21A decreases.

  On the other hand, by reducing the dissolved ozone concentration at the outlet of the ozone reaction tank 11A, the microorganisms attached to the organism / activated carbon layer 23 are not damaged by ozone oxidation, and the activity of the microorganisms can be enhanced. As a result, the biological treatment performance can be improved, the load on the microorganism due to oxidation can be reduced, and the lifetime of the microorganism can be extended as compared with the conventional techniques described in Patent Documents 1 to 3. Furthermore, oxidation of activated carbon can be prevented by reducing the dissolved ozone concentration, and the life of activated carbon can be extended as compared with the prior art described in Patent Documents 1 to 3. Further, since the biodegradable COD component in the ozone reaction tank 11A is reduced as compared with the prior art described in Patent Documents 1 to 3, the adsorption performance of activated carbon continues.

  According to the water treatment system 100A of the present embodiment, in a water treatment method combining ozone treatment and biological treatment, the biological activity in biological treatment can be increased, the life of activated carbon and microorganisms attached thereto can be extended, and biological treatment performance can be improved. Can be increased. Thereby, a highly economical water treatment system with good treatment efficiency can be provided.

<< Modification of First Embodiment >>
Hereinafter, a modification of the present embodiment will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing the configuration of a water treatment system according to a modification of the first embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 2, the water treatment system 100B of the present modification is simply replaced with a biological / active carbon treatment tank (biological reaction tank) 21B instead of the biological / active carbon treatment tank 21A which is the biological treatment apparatus in the first embodiment. The other configuration is the same as that of the water treatment system 100A in the first embodiment.
In the biological / active carbon treatment tank 21B, the exhaust ozone generated in the ozone reaction tank 11A is decomposed by the exhaust ozone treatment device 19 and then injected through an air diffuser 49 arranged at the bottom of the biological / active carbon treatment tank 21B. The configuration of the biological / activated carbon treatment tank 21B is the same as the configuration of the biological / activated carbon treatment tank 21A in the first embodiment.
Exhaust gas from the exhaust ozone treatment device 19 is oxygen after ozone treatment, and by injecting it into the biological / activated carbon treatment tank 21B, the concentration of dissolved oxygen can be increased and the activity of microorganisms can be enhanced. Thereby, the biological treatment performance can be improved. Further, when the ozone concentration in the exhaust ozone flow path 17 is low, the exhaust ozone treatment device 19 may not be used, but may be directly injected into the biological / activated carbon treatment tank 21B.

  According to the water treatment system 100B of this modified example, in the water treatment method that combines ozone treatment and biological treatment, the dissolved oxygen concentration in the biological treatment tank can be increased more than in the first embodiment, and the biological treatment in biological treatment can be improved. The activity can be enhanced and the biological treatment performance can be enhanced. By this effect, a highly economical water treatment system can be provided.

<< Second Embodiment >>
Next, a water treatment system according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view showing the configuration of the water treatment system according to the second embodiment, and FIG. 4 is a schematic diagram for explaining the mechanism of biofilm filtration.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 3, the water treatment system 103 in the present embodiment is simply replaced with a biofilm filtration tank (biological reaction tank) 41 in the biological / activated carbon treatment tank 21A that is the biological treatment apparatus in the first embodiment. Other configurations are the same as the water treatment system 100A in the first embodiment.

As shown in FIG. 3, the biofilm filtration tank 41 according to the present embodiment includes support plates 45A and 45B arranged at intervals in the water tank up and down, and a biological immobilization held between the support plates 45A and 45B. The treated water that is composed of the activated carrier layer 43, is introduced into the upper side of the biological immobilization carrier layer 43 from the ozone treated water outflow passage 32, and passes through the biological immobilization carrier layer 43 downward. 33 is discharged.
A blower 47 for backwashing the biological immobilization carrier layer 43 is provided, and an air diffuser 49 in which air discharged from the blower 47 is disposed at the bottom of the biofilm filtration tank 41 below the support plate 45A of the biofilm filtration tank 41. The backwash drainage channel 34 is installed at a position above the support plate 45B.

  The biological immobilization carrier 43a (see FIG. 4) is, for example, a general filter medium such as anthracite. As shown in FIG. 4, a microorganism formed by attaching microorganisms around the biological immobilization carrier 43a. A membrane 43b is formed, which performs biological treatment. The treated water in the biofilm filtration tank 41 is drained from the treated water drainage channel 33.

Since the operations and effects of the microbubble generating device 1A and the ozone reaction tank 11A in the present embodiment are the same as those in the first embodiment, a duplicate description is omitted, and the operations, effects, and water treatment of the biofilm filtration tank 41 are omitted. Only the effect of the system 103 will be described.
The BOD component and the biodegradable COD component remaining without being decomposed accompany the ozone-treated water, and flow into the biofilm filtration tank 41 through the ozone-treated water outflow passage 32. Suspended solids (SS) component 35 (see FIG. 4) entrained in the ozone-treated water is captured in the voids of the bioimmobilized carrier layer 43 and filtered.
In the bioimmobilized carrier layer 43 held on the support plates 45A and 45B provided in the biofilm filtration tank 41, the BOD component in the ozone-treated water is decomposed by the microbial film 43b attached to the surface of the bioimmobilized carrier 43a. Is done.

  In this treatment, decomposition of the COD component of the water to be treated supplied to the water treatment system 103 is promoted by the high reactivity of the ozone microbubbles, the biodegradable COD component is reduced, and the BOD component is increased. Thereby, the organic matter decomposed in the biofilm filtration tank 41 which is a biological treatment apparatus increases, and the organic matter of the treated water discharged from the biofilm filtration tank 41 decreases. In addition, due to the high reactivity of the ozone microbubbles, the dissolved ozone concentration of the ozone treated water flowing from the ozone reaction tank 11A into the biofilm filtration tank 41 is decreased, so that the ozone injection rate in the ozone reaction tank 11A can be increased. This further reduces the biodegradable COD component and increases the BOD component, so that the organic matter decomposed by the biological treatment in the biofilm filtration tank 41 increases, and the treated water discharged from the biofilm filtration tank 41 Organic matter is reduced.

  Incidentally, by blowing air from the diffuser tube 49 with the blower 47, when the bubbles pass upward through the bioimmobilization support layer 43, the air passes through the bioimmobilization support 43a, and the bioimmobilization support 43a is swung. The suspended solid component 35 that has been filtered is washed away by an upward flow generated together with bubbles, and discharged from the backwash drainage channel 34.

  According to the water treatment system 103 of the present embodiment, in the water treatment method that combines the ozone treatment and the membrane filtration treatment of the biological immobilization support layer 43, the organic treatment performance is improved by improving the ozone treatment efficiency by using microbubbles. Can be increased. Moreover, the suspended | floating matter component 35 accompanying the to-be-processed water can also be capture | acquired and water quality can be improved. Furthermore, by reducing the dissolved ozone concentration in the ozone treated water, it is possible to increase the activity of the organism in the biological treatment and enhance the biological treatment performance, reduce the burden on the organism due to ozone oxidation in the biological treatment, and improve the life of the organism. Can be extended to reduce maintenance costs. Thereby, a highly economical water treatment system can be provided.

In addition, the structure of the biofilm filtration tank 41 in this embodiment is not limited to what was mentioned above, For example, the bioimmobilization support | carrier which used floating foamed polypropylene (floating filter material) as the bioimmobilization support | carrier 43a. The layer 43 may be held between the supports 45 </ b> A and 45 </ b> B, and the ozone-treated water may be allowed to flow from below to above the biological immobilization carrier layer 43.
In this case, the backwashing is performed by flowing the treated water from the top of the biological immobilization support layer 43 to the bottom with a separate pump and filtering the suspended matter from the backwash drainage channel 34 provided at the bottom of the biofilm filtration tank 41. The component 35 is discharged.

<< Third Embodiment >>
Next, a water treatment system according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a longitudinal sectional view showing the configuration of the water treatment system according to the third embodiment, and FIG. 6 is a schematic diagram for explaining the mechanism of the biofilm.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 5, the water treatment system 105 in the present embodiment is simply replaced with a biofilm separation tank (biological reaction tank) 51 in the biological / activated carbon treatment tank 21A that is the biological treatment apparatus in the first embodiment. Other configurations are the same as the water treatment system 100A in the first embodiment.
A separation membrane 53 is incorporated in the biofilm separation tank 51 in the present embodiment. As shown in FIG. 6, the ozone-treated water introduced into the lower primary header region 54 </ b> A of the lower part of the biofilm separation tank 51 is separated from the primary flow path 52 </ b> A of the separation membrane 53 to the secondary side of the separation membrane 53. It passes through the flow path 52B, gathers in the upper secondary header area 54C, and is drained from the treated water drain flow path 33.

For such a configuration, the lower end of the secondary side flow path 52B is closed by the lower end isolation member 53a, and the upper end of the primary side flow path 52A is closed by the upper end isolation member 53b that isolates the secondary side header area 54C. In addition, the primary upper header area 54B communicates with each other.
A blower 47 for backwashing the separation membrane 53 is provided, and the discharge air from the blower 47 is piped so as to be led to an air diffuser tube 49 arranged in the primary side lower header region 54A. Further, the primary upper header region 54B is connected to the backwash drainage channel 34, and the backwash drainage channel 34 is provided with a backwash drainage channel valve (not shown) that is normally closed.

Since the operations and effects of the microbubble generating device 1A and the ozone reaction tank 11A in the present embodiment are the same as those in the first embodiment, duplicate descriptions are omitted, and the operations, effects, and water treatment of the biofilm separation tank 51 are omitted. Only the effect of the system 105 is described.
As shown in FIG. 6, microorganisms 53c adhere to the surface of the separation membrane 53, and biological treatment is performed. The ozone microbubbles injected into the ozone reaction tank 11A are mixed with the water to be treated, and the COD component in the water to be treated is decomposed into BOD components by the ozone microbubbles. The BOD component and the biodegradable COD component remaining without being decomposed accompany the ozone-treated water, and flow into the biofilm separation tank 51 through the ozone-treated water outflow passage 32. On the surface of the primary flow path 52A of the separation membrane 53, the suspended solid component 35 accompanying the ozone-treated water is also captured and separated. In the separation membrane 53 provided in the biofilm separation tank 51, the BOD component in the ozone-treated water is decomposed by the microorganisms 53c attached to the surface of the primary channel 52A.

  In ozone treatment, decomposition of the COD component of the water to be treated supplied to the water treatment system 105 is accelerated by the high reactivity of the ozone microbubbles, the biodegradable COD component is reduced, and the BOD component is increased. Thereby, the organic matter decomposed | disassembled by biological treatment increases, and the organic matter of the treated water discharged | emitted from the biofilm separation tank 51 reduces. In addition, due to the high reactivity of the ozone microbubbles, the dissolved ozone concentration of the ozone microbubble treated water flowing into the biofilm separation tank 51 from the ozone reaction tank 11A is decreased, so that the ozone injection rate in the ozone reaction tank 11A can be increased. This further reduces the biodegradable COD component and increases the BOD component, further increasing the organic matter decomposed by the biological treatment, and reducing the organic matter of the treated water discharged from the biofilm separation tank 51. .

  Incidentally, when the above-described backwash drainage flow path valve (not shown) is opened, air is blown from the diffuser tube 49 by the blower 47, so that when the bubbles pass upward through the primary flow path 52A, the separation membrane 53 is shaken. Then, the suspended solid component 35 filtered at that time is pushed upward by the upward flow generated along with the bubbles, and discharged from the backwash drainage channel 34.

  According to the water treatment system 105 of the present embodiment, in the water treatment method combining ozone treatment and biofilm separation treatment, organic matter removal performance can be enhanced by improving the ozone treatment efficiency by using microbubbles. Moreover, the suspended | floating matter component 35 accompanying the to-be-processed water can also be capture | acquired and water quality can be improved. Furthermore, by reducing the dissolved ozone concentration in the ozone treated water, it is possible to increase the activity of the organism in the biological treatment and enhance the biological treatment performance, reduce the burden on the organism due to ozone oxidation in the biological treatment, and improve the life of the organism. Can be extended to reduce maintenance costs. Thereby, a highly economical water treatment system can be provided.

  5 and 6 schematically illustrate the separation membrane 53 on a flat plate, the shape of the separation membrane 53 is not limited thereto. For example, a cylindrical separation membrane or a thin hollow fiber membrane is used as the separation membrane 53, and a large number of hollow fiber membranes are bundled at both ends and stored in one pipe. A unit which is partitioned by a separating member so that the outer side of the secondary side and the hollow fiber is the primary side may be used.

<< Fourth Embodiment >>
Next, a water treatment system according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a longitudinal sectional view showing the configuration of the water treatment system according to the fourth embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
In the water treatment system 107 in the present embodiment, as shown in FIG. 7, the biological / activated carbon treatment tank 21 </ b> A that is the biological treatment apparatus in the first embodiment is replaced with a biological treatment tank (biological reaction tank) 55 and a sedimentation tank 56. However, the other configuration is the same as the water treatment system 100A in the first embodiment.

  A biological carrier 57 such as sludge is introduced into the biological treatment tank 55 in this embodiment. Microorganisms adhere to the biological carrier 57 and perform biological treatment. The biological treatment tank 55 is provided with a blower 47 for aeration, and is piped so that the air discharged from the blower 47 is led to an aeration tube 49 disposed at the bottom of the biological treatment tank 55. The biological treatment tank 55 communicates with the sedimentation basin 56 at the upper part. In the sedimentation basin 56, sludge is deposited. The bottom of the sedimentation basin 56 and the bottom of the biological treatment tank 55 are connected by a return pipe 58a, and a return pump 58b is provided in the middle of the return pipe 58a.

Since the operations and effects of the microbubble generating device 1A and the ozone reaction tank 11A in the present embodiment are the same as those in the first embodiment, duplicate descriptions are omitted, and the operations and effects of the biological treatment tank 55 and the sedimentation basin 56 are omitted. Only the effect of the water treatment system 107 will be described.
The ozone microbubbles injected into the ozone reaction tank 11A are mixed with the water to be treated, and the COD component in the water to be treated is decomposed into BOD components by the ozone microbubbles. The BOD component and the biodegradable COD component remaining without being decomposed are accompanied by the ozone-treated water and flow into the biological treatment tank 55 through the ozone-treated water outflow passage 32. In the biological treatment tank 55, air is aerated by the blower 47 and the diffuser tube 49, oxygen of microorganisms in the biological treatment tank 55 is supplied, and the activity of the microorganisms increases.

  The BOD component in the ozone-treated water is decomposed by the microorganisms attached to the biological carrier 57. The biological carrier 57 moves from the biological treatment tank 55 to the sedimentation basin 56 together with the treated water, and settles at the bottom of the sedimentation basin 56. The biological carrier 57 that has settled is returned to the biological treatment tank 55 through a return system 58 including a return pipe 58a, a return pump 58b, and the like. The biological carrier 57 returned to the bottom of the biological treatment tank 55 rises from the bottom by the upward flow caused by aeration and is stirred with the ozone-treated water.

  In ozone treatment, due to the high reactivity of ozone microbubbles, decomposition of organic matter in the water to be treated supplied to the water treatment system is promoted, biodegradable COD components are reduced, and BOD components are increased. Thereby, the organic matter decomposed | disassembled by biological treatment increases, and the organic matter of the discharged | emitted process water reduces. In addition, due to the high reactivity of the ozone microbubbles, the dissolved ozone concentration of the ozone microbubble treated water flowing from the ozone reaction tank 11A into the biological treatment tank 55 is decreased, so that the ozone injection rate in the ozone reaction tank 11A can be increased. This further reduces the biodegradable COD component and increases the BOD component, further increasing the organic matter decomposed by the biological treatment, and reducing the organic matter in the treated water discharged from the sedimentation basin 56.

  According to the water treatment system 107 of the present embodiment, in a water treatment method that combines ozone treatment, biological treatment, and a sedimentation basin, organic matter removal performance can be enhanced by improving ozone treatment efficiency by using microbubbles. . In addition, by reducing the concentration of dissolved ozone in ozone-treated water, the biological activity in biological treatment can be enhanced and biological treatment performance can be improved, and the life on the organism can be reduced by reducing the burden on the organism due to ozone oxidation in biological treatment. Can be extended to reduce maintenance costs. Thereby, a highly economical water treatment system can be provided.

<< Fifth Embodiment >>
Next, a water treatment system according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a longitudinal sectional view showing the configuration of the water treatment system in the fifth embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 8, the water treatment system 109 in this embodiment is an activated carbon treatment tank (activated carbon adsorption tank) in which a biological / activated carbon treatment tank 21 </ b> A, which is a biological treatment apparatus in the first embodiment, is arranged at the subsequent stage of the ozone reaction tank 11 </ b> A. The other configuration is the same as that of the water treatment system 100A in the first embodiment. An activated carbon layer 73 is installed in the activated carbon treatment tank 71.

The ozone microbubbles injected into the ozone reaction tank 11A are mixed with the water to be treated, and the COD component in the water to be treated is decomposed into BOD components by the ozone microbubbles. The BOD component and the biodegradable COD component remaining without being decomposed accompany the ozone-treated water, and flow into the activated carbon treatment tank 71 through the ozone-treated water outflow passage 32.
An activated carbon layer 73 is installed in the activated carbon treatment tank 71, and the BOD component and the biodegradable COD component are adsorbed and removed by the activated carbon.

  In ozone treatment, due to the high reactivity of ozone microbubbles, decomposition of organic matter in the water to be treated supplied to the water treatment system is promoted, and biodegradable COD components are reduced. Thereby, the organic matter of the treated water discharged | emitted from the activated carbon treatment tank 71 reduces. Further, due to the high reactivity of the ozone microbubbles, the dissolved ozone concentration of the ozone microbubble treated water flowing into the activated carbon treatment tank 71 from the ozone reaction tank 11A is decreased, so that the ozone injection rate in the ozone reaction tank 11A can be increased. This further reduces biodegradable COD components.

On the other hand, by reducing the dissolved ozone concentration, the activated carbon can be prevented from being oxidized, and the life of the activated carbon can be extended compared to the conventional case.
According to the water treatment system 109 of this embodiment, in the water treatment method that combines ozone treatment and activated carbon treatment, organic matter removal performance can be improved by improving the ozone treatment efficiency by using microbubbles. Moreover, the lifetime of activated carbon can be extended and the maintenance cost can be reduced. Due to the above effects, a highly economical water treatment system can be provided.

<Modification>
The first embodiment and its modifications, and the modifications of the second to fifth embodiments will be described with reference to FIGS. FIG. 9 is a longitudinal sectional view showing the configuration of the water treatment system in the first modified example, and FIG. 10 is a longitudinal sectional view showing the configuration of the water treatment system in the second modified example.
Here, a case where the present invention is applied to the first embodiment will be described as an example, but the present invention can be applied to other modified examples of the first embodiment and the second to fifth embodiments.
In addition, the same code | symbol is attached | subjected about the same structure as 1st Embodiment, and the overlapping description is abbreviate | omitted.

(First modification)
In the water treatment system 100C shown in FIG. 9, the microbubble generator 1B is replaced with the microbubble generator 1B in the first embodiment, and the ozone reaction tank 11B is replaced with the ozone reaction tank 11A. The treated water supply flow path 31 is connected to the upstream side of the ozone gas mixing device 3, and ozone microbubbles are directly generated in the entire amount of treated water in the flow path. The water to be treated in which the ozone microbubbles are generated is injected from the injection pipe 7 into the first compartment 11a of the ozone reaction tank 11B. Therefore, in the microbubble generator 1B, the water to be treated is not circulated, and one-way ozone injection is performed. Thereby, the contact of water to be treated and ozone microbubbles can be promoted.
Also in this case, the ozone discharge current of the ozone generator 2 corresponding to the signal from the dissolved ozone concentration meter 12 disposed near the discharge port of the ozone reaction tank 11B by manual control or automatic control by the control device 10, An inverter (not shown) that drives the pump 4 may be controlled to adjust the amount of dissolved ozone at the outlet of the ozone reaction tank 11A.

(Second modification)
In the water treatment system 100D shown in FIG. 10, the ozone reaction tank 11A is simplified by replacing the ozone reaction tank 11A in the first embodiment with an ozone reaction tank 11C from which the partition plate 13 is deleted.

  According to the water treatment systems 100C and 100D of the first and second modified examples, by using ozone microbubbles, the organic matter removal performance of the water treatment system based on ozone treatment and biological treatment can be improved, and maintenance management can be performed. Cost can be reduced. Thereby, a highly economical water treatment system can be provided.

(Other variations)
Furthermore, the use of exhaust ozone in the modification of the first embodiment can be applied not only to the first embodiment but also to the second to third embodiments.

It is a longitudinal section showing the composition of the water treatment system concerning a 1st embodiment. It is a longitudinal cross-sectional view showing the structure of the water treatment system concerning the modification of 1st Embodiment. It is a longitudinal cross-sectional view showing the structure of the water treatment system concerning 2nd Embodiment. It is a schematic diagram explaining the mechanism of biofilm filtration. It is a longitudinal cross-sectional view showing the structure of the water treatment system concerning 3rd Embodiment. It is a schematic diagram explaining the mechanism of a biofilm. It is a longitudinal cross-sectional view showing the structure of the water treatment system concerning 4th Embodiment. It is a longitudinal cross-sectional view showing the structure of the water treatment system in 5th Embodiment. It is a longitudinal cross-sectional view showing the structure of the water treatment system in a 1st modification. It is a longitudinal cross-sectional view showing the structure of the water treatment system in a 2nd modification.

Explanation of symbols

1A, 1B Microbubble generator 2 Ozone generator 3 Ozone gas mixing device 4 Pump 5 Air / water separation device 6 Nozzle (pressure reduction device)
7 Injection pipe 8 Extraction pipe 10 Control device 11A, 11B, 11C Ozone reaction tank 12 Dissolved ozone concentration meter 13, 13A, 13B, 13C Partition plate 21A, 21B Biological / activated carbon treatment tank (biological reaction tank)
23 Bioactive activated carbon layer 30 Circulating flow path 31 Untreated water supply flow path 32 Ozone treated water outflow path 33 Treated water drainage path 34 Backwash drainage path 41 Biofilm filtration tank (biological reaction tank)
43 Bioimmobilization support layer 43a Bioimmobilization support 47 Blower 49 Aeration tube 51 Biofilm separation tank (biological reaction tank)
53 Separation membrane (membrane separation device)
55 Biological treatment tank (biological reaction tank)
56 Sedimentation basin 71 Activated carbon treatment tank (activated carbon adsorption device)
73 Activated carbon layer 100A, 100B, 100C, 100D, 103, 105, 107, 109 Water treatment system

Claims (11)

An ozone generator for generating ozone gas;
A microbubble generator that generates microbubbles using the ozone gas generated by the ozone generator as a gas source;
An ozone reaction tank for injecting ozone microbubbles generated by the microbubble generator into the water to be treated and oxidizing the water to be treated;
An organic matter biological treatment apparatus provided at a subsequent stage of the ozone reaction tank,
After decomposing the organic matter in the water to be treated in the ozone reaction tank using the ozone microbubble, the organic substance is not easily decomposed in the ozone reaction tank, and biodegradable by the ozone microbubble. A water treatment system, wherein a denatured organic substance is biologically treated by the biological treatment apparatus. The microbubble generator is
An ozone gas mixing device that mixes ozone gas generated by the ozone generator into the water to be treated;
A pump for pressurizing the water to be treated mixed with the ozone gas;
A pressure reducing device that generates microbubbles by depressurizing water to be treated mixed with ozone gas pressurized by the pump;
The water treatment system according to claim 1, further comprising: The ozone reaction tank is divided into partition sections that can flow from the front stage to the rear stage with a plurality of partition plates, and receives the water to be treated in the front partition section,
The said micro bubble production | generation apparatus produces | generates the said ozone micro bubble in the said to-be-processed water extracted from the said front partition, and inject | pours it into the said front partition again. The described water treatment system. The biological treatment apparatus comprises:
It consists of a biological reaction tank with microorganisms fixed to a fixed bed,
Activated carbon is used for the fixed bed, a biofilm is formed on the activated carbon layer,
The water treatment system according to any one of claims 1 to 3, wherein an organic substance in the water to be treated into which the ozone microbubbles are injected is decomposed by the biofilm and adsorbed by the activated carbon. . The biological treatment apparatus comprises:
It consists of an aeration device and a biological reaction tank having a biological immobilization carrier,
The water treatment system according to any one of claims 1 to 3, wherein the organic matter in the treated water into which the ozone microbubbles are injected is decomposed by microorganisms held on the biological immobilization support. The biological treatment apparatus comprises:
It is composed of a biological reaction tank having a membrane separation device for separating the organic matter in the treated water by passing the treated water from the primary side to the secondary side of the membrane,
The water according to any one of claims 1 to 3, wherein the organic matter in the water to be treated into which the ozone microbubbles are injected is decomposed by microorganisms held on the membrane surface of the membrane separation device. Processing system. The biological treatment apparatus comprises:
Consists of a biological reaction tank having a filter medium for filtering the water to be treated,
The water treatment system according to any one of claims 1 to 3, wherein the organic matter in the water to be treated into which the ozone microbubbles are injected is decomposed by microorganisms held in the filter medium. The biological treatment apparatus is composed of a biological reaction tank and a sedimentation basin,
The organic matter in the water to be treated into which the ozone microbubbles are injected is decomposed by microorganisms introduced into the biological reaction tank, and the microorganisms are precipitated in the sedimentation basin and separated from the treated water. The water treatment system according to any one of claims 3 to 4.   The water treatment system according to any one of claims 3 to 8, wherein exhaust ozone gas from the ozone reaction tank is supplied to a biological reaction tank of the biological treatment apparatus. An ozone generator for generating ozone gas;
A microbubble generating device that generates microbubbles using ozone gas generated by the ozone generator as a gas source;
An ozone reaction tank for injecting ozone microbubbles generated by the microbubble generator into the water to be treated and oxidizing the water to be treated;
An activated carbon adsorbing device provided at a subsequent stage of the ozone reaction tank,
After decomposing the organic matter in the water to be treated in the ozone reaction tank using ozone microbubbles, the organic substance is not easily decomposed in the ozone reaction tank, and the biodegradability is modified by ozone microbubbles. The water treatment system characterized by carrying out the adsorption process in the said activated carbon adsorption apparatus. A controller that controls at least the amount of ozone generated by the ozone generator and the rotational speed of the pump;
A dissolved ozone concentration meter that measures the ozone concentration of the treated water that has been oxidized in the ozone reaction tank,
The control device compares the measured value of the dissolved ozone concentration meter with the ozone concentration target value, calculates the excess or deficiency of the amount of ozone injected into the water treatment tank, and based on the calculation result, calculates the rotational speed of the pump. The water treatment system according to claim 2, wherein an ozone generation amount of the ozone generator is controlled.

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