JP4357316B2 - Wastewater treatment equipment - Google Patents

Description

  The present invention relates to a wastewater treatment apparatus for treating various wastewaters such as wastewater generated when livestock manure is subjected to solid-liquid separation treatment.

  The wastewater produced when solid-liquid separation of livestock manure contains organic substances that exceed regulatory limits, nitrogen compounds such as ammonia, and phosphorus compounds, so these cannot be discharged directly into rivers. . Therefore, various techniques for decomposing organic substances, nitrogen compounds, phosphorus compounds, and the like have been developed, and there is a technique described in Patent Document 1 as a technique related to the present application.

  In the degradation technique of environmental pollutants described in Patent Document 1, an aqueous solution containing environmental pollutants is stored in a reaction vessel in which an ultrasonic vibrator and an ultraviolet lamp are arranged, and ultrasonic waves are applied to the aqueous solution. Organic substances, nitrogen compounds, phosphorus compounds, etc. are decomposed by irradiation with ultraviolet rays.

Japanese Patent Laying-Open No. 2003-126585 (page 3-6)

  In the decomposition technique described in Patent Document 1, a sound wave vibrator is used as the ultrasonic wave generating means. However, since the ultrasonic wave vibrator is difficult to increase in size due to its nature, the apparatus is large. And the processing capacity cannot be increased.

  In addition, since the ultrasonic vibrator literally vibrates ultrasonically, it deteriorates within a relatively short period of time, and the ultrasonic wave generation function is likely to be lowered and the durability is low. For this reason, periodic maintenance is necessary to maintain the performance of the apparatus, and maintenance is troublesome.

  The problem to be solved by the present invention is that organic substances, ammonia, phosphorus compounds, etc. contained in the wastewater to be treated can be efficiently decomposed, the apparatus can be easily enlarged, and has excellent durability. It is to provide a waste water treatment device.

The waste water treatment apparatus of the present invention includes a storage tank that can store a liquid, a decomposition tank that is arranged in the processing tank and separated from the processing tank, and has an outlet for allowing the liquid to flow into the storage tank, and a decomposition tank A wastewater treatment device comprising a microbubble generator disposed inside, a liquid supply path for supplying liquid to the microbubble generator, and a drainage path for discharging liquid in the storage tank ,
The outlet of the decomposition tank is provided at a position higher than the liquid level of the liquid stored in the storage tank,
Fine-bubble generator, and the fluid is pivotable circular cylindrical swirl chamber, and two liquid introduction path provided in the tangential direction of the whirling chamber for introducing the liquid to be supplied to the swirl chamber from the liquid supply path A discharge port formed on each of both end surfaces in the axial direction of the swirl chamber for discharging fluid mixed with fine bubbles formed by swirling flow generated in the swirl chamber by the liquid flowing in from the liquid introduction path. It is characterized by

  In such a configuration, when a liquid to be processed (liquid to be processed) is supplied to the fine bubble generator through the liquid supply path, a fluid swirling flow is generated in the swirl chamber by the liquid to be processed flowing from the liquid introduction path into the swirl chamber. As a result, a fluid containing fine bubbles is formed in the swirl chamber, and the fluid containing fine bubbles is discharged from the discharge port into the decomposition tank while swirling in the swirl chamber.

  The fluid mixed with fine bubbles discharged from the outlet of the fine bubble generator into the decomposition tank rises while diffusing in the decomposition tank, falls from the outlet provided in the decomposition tank into the storage tank, It is temporarily stored in the storage tank and discharged outside the storage tank through the drainage path.

  In this way, when the liquid to be treated is supplied to the fine bubble generator, it is discharged into the decomposition tank as a fluid mixed with fine bubbles, diffuses and rises in the decomposition tank, then falls into the storage tank, The organic matter, ammonia compound, phosphorus compound, etc. contained in the liquid to be treated can be efficiently decomposed through a process of being temporarily stored in and then discharged. That is, due to the generation of cavitation bubbles in the fine bubble generator, local physicochemical action caused by crushing, and decomposition by ultrasonic waves generated from the fine bubble generator, organic substances, ammonia compounds, phosphorus contained in the liquid to be treated Compounds and the like can be decomposed efficiently.

  In addition, since the wastewater treatment apparatus of the present invention can obtain a decomposition action by ultrasonic waves without using an ultrasonic vibrator, continuous treatment of the liquid to be treated and enlargement of the apparatus are possible. There is no need to replace the child, it is easy to maintain, and has excellent durability.

  In the wastewater treatment apparatus of the present invention, there are some unclear points as to why the organic substance, ammonia, and phosphorus compound in the liquid to be treated are decomposed as described above, but it is not due to the following mechanism. I guess that.

  In the fine bubble generator to which the liquid to be treated is supplied, the liquid to be treated which has flowed into the swirl chamber from the liquid introduction path swirls at a high speed in the swirl chamber, thereby generating a negative pressure cavity at the center thereof. This negative pressure cavity is vortex cavitation with developed vortex cavitation, and is considered to be an aggregate of cavitation bubbles. Both ends of the vortex cavitation in the axial direction develop as cavitation bubbles continue to gather and grow in the direction of the discharge port of the swirl chamber.

  At this time, both ends of the axial center of the vortex cavitation are rapidly compressed and crushed by the liquid whose pressure has been increased when discharged from the discharge port having a smaller cross-sectional area than the swirl chamber. Thus, both ends of the axial center of the vortex cavitation are portions where the growing cavitation bubbles are continuously crushed by the hydraulic pressure. When such cavitation bubbles are crushed, a local reaction field at a high temperature and a high pressure with a temperature of 5000 ° C. to tens of thousands of ° C. and a pressure of several thousand atmospheres is formed, causing a physicochemical action. It is presumed that the phosphorous compound decomposes.

  Furthermore, vortex cavitation is known to cause the most severe cavitation erosion. However, due to the continuous crushing of cavitation bubbles with strong physical reaction, ultrasonic waves with a sound pressure of several tens of dB are generated from the vicinity of the audible range of several hundreds. It occurs in a continuous band up to kHz. Therefore, secondary cavitation bubbles corresponding to the ultrasonic frequency are generated and collapsed in the liquid to be processed without using an ultrasonic vibrator.

  In other words, from “cavitation bubbles with the property of causing a physical reaction such as bactericidal action” generated by relatively low frequency ultrasonic waves, “the property of causing strong chemical reactions” generated by high frequency ultrasonic waves of several hundred kHz It is possible to generate cavitation bubbles with a wide variety of physical and chemical effects, leading to the decomposition of organic matter, ammonia, and phosphorus compounds. Is done.

  In this way, ultrasonic waves in a continuous band from around the audible range to several hundred kHz are generated, so multipurpose wastewater treatment is possible without being restricted by the frequency dependence of the physical and chemical reactions of the ultrasonic waves. It becomes. Furthermore, since it is not necessary to use a plurality of ultrasonic vibrators having different frequencies, it is not necessary to replace the ultrasonic vibrator as described above, the maintenance and management are simple, and the durability is excellent.

  The reaction in the decomposition tank constituting the waste water treatment apparatus of the present invention is due to the reaction of OH radicals generated by the thermal decomposition reaction of water. Hydrogen radicals and OH radicals are generated by the decomposition of water molecules. This OH radical has a stronger oxidizing power than ozone and is a powerful oxidizing agent having electrophilicity. For this reason, it is known that there is a hydrogen abstraction reaction from a hydrogen bond, the selectivity of the reactant is low, the activity is high, and there is a property of decomposing volatile substances and ionic substances. Therefore, ammonia contained in the liquid to be treated is decomposed into nitrogen and water by the reaction with the OH radicals. In addition, the phosphorus compound in the liquid to be treated is decomposed by reaction with hydrogen radicals.

  As described above, ammonia and phosphorus compounds in the liquid to be treated in the decomposition tank are decomposed by the reaction of OH radicals, but when the OH radicals in the liquid increase, the OH radicals combine to form hydrogen peroxide. As a result, the oxidizing power decreases and the decomposition rate decreases. Nitrogen and phosphorus produced by the decomposition are deaerated when the liquid to be treated falls from the outlet of the decomposition tank to the storage tank.

  In the wastewater treatment apparatus of the present invention, since various reactions as described above occur, organic substances, ammonia, phosphorus compounds and the like contained in the wastewater to be treated can be efficiently decomposed and removed. In addition, since an ultrasonic transducer is unnecessary, the durability is excellent and the size of the apparatus is relatively easy.

Here, by providing the outlet of the decomposition tank at a position higher than the liquid level of the liquid stored in the storage tank, the liquid to be processed flowing out of the outlet of the decomposition tank is the liquid level to be processed in the storage tank. Therefore, deaeration is promoted, and nitrogen or hydrogen generated by the decomposition can be efficiently diffused into the atmosphere.

  On the other hand, an ultraviolet ray generating means may be disposed in the storage tank or the decomposition tank. With such a configuration, it becomes possible to irradiate the liquid to be processed from the ultraviolet ray generating means, and ultraviolet rays are generated on the hydrogen peroxide generated in the liquid to be processed by the ultrasonic waves generated from the fine bubble generator. By hitting, since highly active OH radicals are formed, decomposition of ammonia and phosphorus compounds can be further promoted by these OH radicals.

  In addition, if an ultraviolet-ray generation means is arrange | positioned in a storage tank, an ultraviolet-ray can be efficiently irradiated with respect to the to-be-processed liquid which falls in the storage tank from the outflow port of a decomposition tank. In this case, if a plurality of ultraviolet ray generating means are arranged around the decomposition tank in the storage tank, the liquid to be treated falling from the outlet of the decomposition tank into the storage tank can be uniformly irradiated with ultraviolet rays. Further, if the ultraviolet ray generating means is disposed in the decomposition tank, it is possible to promote the decomposition of ammonia and phosphorus compounds in the decomposition tank.

  The present invention has the following effects.

(1) A storage tank that can store a liquid to be processed, a decomposition tank that is arranged in the processing tank and separated from the processing tank, and has an outlet for allowing the liquid to flow into the storage tank; In a wastewater treatment apparatus comprising: a microbubble generator disposed in a tank; a liquid supply path for supplying liquid to the microbubble generator; and a drainage path for discharging liquid in the storage tank. of an outlet provided at a higher position than the liquid surface of the liquid contained in the reservoir, a fine bubble generator, swivel and fluid pivotable circular cylindrical swirl chamber, the liquid supplied from the liquid supply path In order to discharge the fluid mixed with fine bubbles formed by the two liquid introduction paths provided in the tangential direction of the swirl chamber for introduction into the room and the swirl flow generated in the swirl chamber by the liquid flowing in from the liquid introduction path. respectively formed on both end faces in the axial direction of the whirling chamber By providing an outlet, it is possible to efficiently decompose organic substances, ammonia, phosphorus compounds, etc. contained in the liquid to be processed, the equipment can be easily enlarged, and has excellent durability It becomes.

(1) By providing the outlet of the decomposition tank at a position higher than the liquid level of the liquid stored in the storage tank, the liquid to be processed flowing out of the outlet of the decomposition tank faces the liquid to be processed in the storage tank. Therefore, deaeration is promoted, and nitrogen or hydrogen generated by the decomposition can be efficiently diffused into the atmosphere.

(3) By arranging ultraviolet ray generating means in the storage tank or in the decomposition tank, ultraviolet rays hit the hydrogen peroxide generated in the liquid to be treated by the ultrasonic waves generated from the fine bubble generator and highly active OH radicals. Therefore, decomposition of ammonia and phosphorus compounds can be further promoted.

  Hereinafter, a waste water treatment apparatus according to an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view showing a wastewater treatment apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIGS. 3 and 4 are wastewater treatment apparatuses shown in FIG. 5 is a partially cutaway enlarged view of FIG. 4, and FIG. 6 is a sectional view taken along line BB in FIG.

  As shown in FIGS. 1 and 2, the wastewater treatment apparatus 1 of the present embodiment is divided into a cylindrical storage tank 2 capable of storing wastewater to be treated, and the storage tank 2 in the storage tank 2. The decomposition tank 3 arranged in the above, the fine bubble generator 4 arranged in the decomposition tank 3, the liquid supply path 5 for supplying wastewater to the fine bubble generator 4, and the liquid in the storage tank 2 are discharged. And a drainage path 6 for the purpose. The decomposition tank 3 has an octagonal cylindrical shape with a funnel shape at the bottom, and an outlet 3a for allowing the liquid to flow into the storage tank 2 is opened at the upper end thereof.

  The upper part of the storage tank 2 is closed by a removable inner lid 8 and an upper lid 9, a vent hole 8 a is opened in the inner lid 3, and a vent pipe 9 a is attached to the upper lid 9. Four ultraviolet germicidal lamps 7 are attached to the inner lid 8 in a suspended state, and these ultraviolet germicidal lamps 7 are arranged so as to surround the decomposition tank 3 in the storage tank 2.

  As shown in FIGS. 5 and 6 to be described later, the fine bubble generator 4 introduces a cylindrical swirl chamber 10 in which a fluid can swirl and a liquid supplied from the liquid supply path 5 into the swirl chamber 10. Fluid mixed with fine bubbles MB formed by two liquid introduction paths 11 provided in the tangential direction of the swirl chamber 10 and swirl flow R generated in the swirl chamber 10 by the liquid flowing in from these liquid introduction paths 11 The discharge chambers 12 are respectively formed on both end faces in the axial direction of the swirl chamber 10.

  When the waste water treatment apparatus 1 is used, as shown in the lower region of FIG. 3, the liquid supply path 5 and the drainage path 6 are connected to the water outlet P1 and the water inlet P2 of the pump P through the water pipes 5a and 6a, respectively. Then, a circulation path is formed between the waste water treatment apparatus 1 and the pump P. And the waste water W which is a process target is put in the storage tank 2 of the waste water treatment apparatus 1, and the upper surface opening of the storage tank 2 is closed by the inner lid 8 and the upper lid 9.

  Thereafter, when the ultraviolet germicidal lamp 7 is turned on and the pump P is operated, the waste water W in the storage tank 2 is sucked into the pump P via the drainage path 6 and then via the liquid supply path 5. It is supplied toward the fine bubble generator 4. The waste water W supplied to the fine bubble generator 3 is divided into two in the branch member 14 and then flows into the swirl chamber 10 from the two liquid introduction paths 11.

  As shown in FIGS. 5 and 6, the swirl flow R is generated in the swirl chamber 10 by the waste water W flowing into the swirl chamber 10 from the tangential direction, and thereby the fluid mixed with the fine bubbles MB is contained in the swirl chamber R. The formed fluid containing the fine bubbles MB is discharged into the decomposition tank 3 from the discharge ports 12 at both ends of the swirl chamber 10 while swirling in the swirl chamber 10.

  As shown in FIG. 4, the fluid mixed with the microbubbles MB discharged from the discharge port 12 of the microbubble generator 4 into the decomposition tank 3 rises while diffusing in the decomposition tank 3. After falling into the storage tank 2 from the outlet 3a at the upper end and temporarily staying in the storage tank 2, it is sucked into the pump P via the drainage path 6, discharged to the outside of the storage tank 2, and then supplied. The liquid is again supplied to the fine bubble generator 4 via the liquid path 5, and the above-described process is repeated.

  As described above, when the waste water W is supplied to the fine bubble generator 4, it is discharged into the decomposition tank 3 as a fluid mixed with the fine bubbles MB, diffuses and rises in the decomposition tank 3, and then falls into the storage tank 2. By repeating the process of being temporarily stored in the storage tank 2 and then discharged, it is possible to efficiently decompose organic substances, ammonia compounds, phosphorus compounds and the like contained in the waste water W.

  As shown in FIGS. 5 and 6, in the fine bubble generator 4 to which the waste water W is fed, the waste water W that flows into the swirl chamber 10 from the liquid introduction path 11 swirls at a high speed in the swirl chamber 10, A negative pressure cavity V is generated in the central portion. This negative pressure cavity V is vortex cavitation in which vortex cavitation is developed, and is considered to be an aggregate of cavitation bubbles. Both ends of the negative pressure cavity V in the direction of the axis C are developed as cavitation bubbles continue to collect and grow in the direction of the discharge port 12 of the swirl chamber 10.

  At this time, both ends of the negative pressure cavity V in the direction of the axis C are rapidly compressed and crushed by the fluid with increased pressure when discharged from the discharge port 12 having a smaller cross-sectional area than the swirl chamber 10. Thus, both ends of the negative pressure cavity V in the direction of the axis C are portions where the growing cavitation bubbles are continuously crushed by the hydraulic pressure. When such cavitation bubbles are crushed, a local reaction field of a high temperature and a high pressure of 5000 to tens of thousands of degrees Celsius and a pressure of several thousand atmospheres is formed, causing a physicochemical action. It is presumed to exert the decomposition action of the phosphorus compound.

  Further, the negative pressure cavity V has the property of causing cavitation erosion most severely, but due to the continuous crushing of cavitation bubbles having a strong physical reaction action, several hundreds of audible regions are present inside and outside the fine bubble generator 4. An ultrasonic wave having a sound pressure of several tens dB is generated in a continuous band up to kHz. Therefore, in the waste water W, secondary cavitation bubbles corresponding to the ultrasonic frequency are generated and collapsed without using the ultrasonic vibrator.

  In other words, it has the property of causing a strong chemical reaction generated by ultrasonic waves of several hundred kHz from the “cavitation bubble having the property of causing physical reactions such as bactericidal action” generated by ultrasonic waves of relatively low frequency. Cavitation bubbles having a wide variety of physical and chemical effects are generated by the fine bubble generator 4, leading to the decomposition of organic matter, ammonia and phosphorus compounds. The

  In this way, since the fine bubble generator 4 generates ultrasonic waves in a continuous band from the vicinity of the audible range to several hundred kHz, without being restricted by the frequency dependence of the physical and chemical reactions of the ultrasonic waves. Multi-purpose wastewater treatment becomes possible. Furthermore, since it is not necessary to use a plurality of ultrasonic vibrators having different frequencies, it is not necessary to replace the ultrasonic vibrator, the maintenance and management are simple, and the durability is excellent.

  The reaction in the decomposition tank 2 constituting the waste water treatment apparatus 1 is due to the reaction of OH radicals generated by the thermal decomposition reaction of water. Hydrogen radicals and OH radicals are generated by the decomposition of water molecules. This OH radical has a stronger oxidizing power than ozone and is a powerful oxidizing agent having electrophilicity. Therefore, there is a hydrogen abstraction reaction from a hydrogen bond, the selectivity of the reactant is low, the activity is high, and there is a property of decomposing volatile substances and ionic substances. Therefore, ammonia contained in the waste water W is decomposed into nitrogen and water by the reaction with the OH radicals. Further, the phosphorus compound in the waste water W is decomposed by reaction with hydrogen radicals.

  As described above, ammonia and phosphorus compounds in the waste water W in the decomposition tank 2 are decomposed by the reaction of OH radicals, but when the OH radicals in the waste water W increase, the OH radicals combine to form hydrogen peroxide. As a result, the oxidizing power decreases and the decomposition rate decreases. As shown in FIG. 4, the nitrogen and phosphorus generated by the decomposition are deaerated when the waste water W falls from the outlet 3 a of the decomposition tank 3 to the storage tank 2.

  In the wastewater treatment apparatus 1 of the present embodiment, since various reactions as described above occur, organic substances, ammonia, phosphorus compounds, etc. contained in the wastewater W to be treated are efficiently decomposed and removed. Can do. In addition, since an ultrasonic transducer is unnecessary, the durability is excellent and the size of the apparatus is relatively easy.

  Moreover, in the waste water treatment apparatus 1 of this embodiment, the outflow port 3a of the decomposition tank 3 is provided at a position higher than the liquid level of the waste water W accommodated in the storage tank 2. Thereby, since the waste water W flowing out from the outlet 3a of the decomposition tank 3 falls toward the water surface of the waste water W in the storage tank 2, deaeration is promoted, and nitrogen and hydrogen generated by the decomposition are removed. Efficiently dissipate into the atmosphere.

  Furthermore, an ultraviolet germicidal lamp 7 as an ultraviolet ray generating means is disposed in the storage tank 2 and irradiates the waste water W with ultraviolet rays, so that it is generated in the waste water W by ultrasonic waves generated from the fine bubble generator 4. By irradiating the hydrogen peroxide to be irradiated with ultraviolet rays, highly active OH radicals are formed. These OH radicals can further promote the decomposition of ammonia and phosphorus compounds. Since the four ultraviolet germicidal lamps 7 are arranged in the storage tank 2 so as to surround the decomposition tank 3, the waste water W falling into the storage tank 2 from the outlet 3 a of the decomposition tank 3. UV light can be irradiated evenly.

  The use of the wastewater treatment apparatus 1 of the present embodiment is not particularly limited, but is suitable as a means for treating livestock excreta wastewater from which solid components have been removed after the solid-liquid separation process, It is also suitable as a subsequent processing means.

  In addition, the waste water treatment apparatus 1 is not limited to use in the piping state shown in the lower region of FIG. 3, but as shown in the upper region of FIG. 6 and a preliminary tank 13 and a pipe 6c between the preliminary tank 13 and the pump P, and a circulation path is formed between the drainage device 1, the preliminary tank 13 and the pump P. It can also be used. If used in such a piping state, a relatively large amount of wastewater treatment can be performed.

  Next, with reference to FIG. 7, the waste water treatment apparatus 20 which is other embodiment of this invention is demonstrated. In addition, about the part which demonstrates the same function and effect as the waste water treatment apparatus 1 mentioned above in the waste water treatment apparatus 20 shown in FIG. 7, the same code | symbol as FIGS. 1-6 is attached | subjected and description is abbreviate | omitted.

  In the wastewater treatment apparatus 20, the ultraviolet germicidal lamp 7 is disposed above the fine bubble generator 4 in the decomposition tank 3. Therefore, decomposition of ammonia and phosphorus compounds in the decomposition tank 3 can be promoted. Further, in addition to the sterilizing action against prokaryotes (such as Escherichia coli) by the microjet flow generated by the collapse of the cavitation bubbles, the sterilizing action of the ultraviolet germicidal lamp 7 is also particularly useful during discharge.

  The waste water treatment apparatus of the present invention can be used in the field of treating waste water generated when solid-liquid separation of livestock manure is performed, and also in the field of treating food industry waste water and industrial waste water separated in solid and liquid. Can be widely used.

It is a longitudinal cross-sectional view which shows the waste water treatment apparatus which is embodiment of this invention. It is the sectional view on the AA line in FIG. It is a figure which shows a use condition of the waste water treatment apparatus shown in FIG. It is a figure which shows the use condition of the waste water treatment apparatus shown in FIG. It is a partially cutaway enlarged view of FIG. It is the BB sectional view taken on the line in FIG. It is a longitudinal cross-sectional view which shows the waste water treatment apparatus which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 Wastewater treatment equipment 2 Storage tank 3 Decomposition tank 3a Outlet 4 Fine bubble generator 5 Liquid supply path 6 Drainage path 5a, 6a, 6b, 6c Water supply pipe 7 Ultraviolet germicidal lamp 8 Middle lid 8a Vent 9 Upper lid 9a Vent pipe 10 Swirl chamber 11 Liquid introduction path 12 Discharge port 13 Preliminary tank 14 Branch member C Axle MB Fine bubble P Pump P1 Water discharge port P2 Water intake port R Swirling flow V Negative pressure cavity W Wastewater

Claims (2)

A storage tank that can store a liquid to be processed, a decomposition tank that is partitioned from the processing tank in the processing tank and has an outlet for allowing the liquid to flow into the storage tank, and in the decomposition tank A wastewater treatment device comprising: a fine bubble generator disposed in the liquid supply path; a liquid supply path for supplying liquid to the fine bubble generator; and a drainage path for discharging liquid in the storage tank. And
The outlet of the decomposition tank is provided at a position higher than the liquid level of the liquid stored in the storage tank,
The fine-bubble generator, and the fluid is pivotable circular cylindrical swirl chamber, two provided in a tangential direction of the swirl chamber for introducing the liquid to be supplied to the whirling chamber from said liquid supply path In order to discharge a fluid containing a fine bubble formed by a liquid introduction path and a swirl flow generated in the swirl chamber by the liquid flowing in from the liquid introduction path , both end surfaces in the axial direction of the swirl chamber are formed respectively . A wastewater treatment apparatus comprising a discharge port. Wastewater treatment apparatus according to claim 1 Symbol placement arranged ultraviolet generating means to said storage tank or the decomposition tank.

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