JP7509605B2 - Oil-containing wastewater separation device and method - Google Patents

Description

The present invention relates to an oil-containing wastewater separation device and method for reducing the volume of oil-containing scum.

JP 2011-45846 A (Patent Document 1) describes an apparatus that separates oil-containing scum from oil-containing wastewater generated in steel plants and reduces its volume by passing the oil-containing scum through multiple stages of vibrating sieves with different mesh sizes to separate water (oil-containing wastewater) from the oil-containing scum. This apparatus can reduce the volume of scum without using many chemicals or thermal energy.

JP 2011-45846 A

However, the oil-containing wastewater separation device described in the above publication requires the arrangement of multiple stages of vibrating screens, which requires a large installation space, and there is still room for improvement in terms of achieving both improved processing efficiency and space saving.

The present invention has been made in view of the above, and its main objective is to provide a technology that contributes to both improving processing efficiency and saving space when separating oil-containing wastewater from oil-containing scum.

According to a preferred embodiment of the oil-containing wastewater separation apparatus of the present invention, an oil-containing wastewater separation apparatus for reducing the volume of oil-containing scum is configured. The oil-containing wastewater separation apparatus includes a storage tank having a bottom surface and capable of storing oil-containing scum, a vibrator, and an oscillator electrically connected to the vibrator so as to supply high-frequency power to the vibrator. The vibrator has an upper surface facing the liquid surface of the oil-containing scum, and is disposed in the storage tank with the upper surface inclined at a predetermined angle with respect to the liquid surface of the oil-containing scum and with a space between the upper surface and the bottom surface .

According to the present invention, the ultrasonic waves generated by the vibrator generate fine bubbles in the oil-containing scum, and cavitation can be actively performed by the change in sound pressure. As a result, the impact pressure generated when the fine bubbles attached to the oil-containing scum disappear (collapse) can effectively separate water (oil-containing wastewater) and dust from the oil-containing scum. Since the upper surface of the vibrator is inclined at a predetermined angle with respect to the liquid surface of the oil-containing scum, the water (oil-containing wastewater) separated from the oil-containing scum does not remain on the upper surface. In other words, the oil-containing scum can always be present on the upper surface of the vibrator, so that the separation of water (oil-containing wastewater) and dust from the oil-containing scum by the cavitation effect can be promoted. In addition, since the upper surface of the vibrator is only inclined at a predetermined angle with respect to the liquid surface of the oil-containing scum, the water (oil-containing wastewater) and dust can be separated from the oil-containing scum with a space-saving and simple structure. In addition, according to the present invention, the water (oil-containing wastewater) separated from the oil-containing scum flows into the space between the vibrator and the bottom surface, and the oil-containing scum can be moved to the upper surface side of the vibrator by the convection effect. In addition, the vibrator can be effectively prevented from being submerged in the water (oil-containing wastewater) separated from the oil-containing scum, which further promotes the separation of the water (oil-containing wastewater) and dirt from the oil-containing scum by the cavitation effect.

According to a further embodiment of the oil-containing wastewater separation device of the present invention, the upper surface of the vibrator has an inclination angle of 15 degrees or more and 25 degrees or less, preferably about 20 degrees, relative to the liquid surface.

As a result of intensive research, the inventors have found that the reduction rate of oil-containing scum is high when the inclination angle of the upper surface of the vibrator with respect to the liquid surface is 15 degrees or more and 25 degrees or less, preferably about 20 degrees. Here, the reduction rate is defined as the reduction rate of the volume caused by removing water (oil-containing wastewater) from the oil-containing scum, and specifically, it is defined as the value obtained by subtracting the "volume of the oil-containing scum after volume reduction (after treatment) in the storage tank" from the "volume of the oil-containing scum before volume reduction (before treatment) in the storage tank" by the "volume of the oil-containing scum before volume reduction (before treatment) in the storage tank", and then multiplying the result by 100. Based on this research result, in this embodiment, the inclination angle of the upper surface of the vibrator with respect to the liquid surface is configured to be 15 degrees or more and 25 degrees or less, preferably about 20 degrees. This can further promote the volume reduction of the oil-containing scum.

According to a further embodiment of the oil-containing wastewater separation device of the present invention, the vibrator is arranged in the storage tank so that the distance between the liquid level and the part of the upper surface closest to the liquid level is 5 cm or more.

After extensive research, the inventors discovered that if the distance between the top surface of the vibrator and the surface of the oil-containing scum is small, the surface of the oil-containing scum vibrates violently, causing the oil-containing scum separated by the effects of ultrasound to instantly remix. Based on these research results, in this embodiment, the distance between the top surface of the vibrator and the surface of the oil-containing scum is set to 5 cm or more. This makes it possible to prevent a decrease in the volume reduction effect of the oil-containing scum.

According to a further embodiment of the oil-containing wastewater separation device of the present invention, the ultrasonic frequency output to the oil-containing scum is 20 kHz or more and 100 kHz or less, preferably about 40 kHz.

As a result of extensive research, the inventors have found that water (oil-containing wastewater) and debris can be effectively separated from oil-containing scum in a specific ultrasonic frequency band. Based on these research results, in this embodiment, the ultrasonic frequency output to the oil-containing scum is set to 20 kHz or more and 100 kHz or less, preferably about 40 kHz. This makes it possible to effectively separate water (oil-containing wastewater) and debris from the oil-containing scum.

According to a further embodiment of the oil-containing wastewater separation device of the present invention, the oil-containing scum stored in the storage tank is 20 L or more and 30 L or less, preferably 30 L, and the high-frequency power is 400 W or more and 600 W or less, preferably 600 W. That is, the oscillator supplies the vibrator with high-frequency power of 20 W or more and 30 W or less, preferably 20 W per 1 L of oil-containing scum.

As a result of intensive research, the inventors have found that there is a correlation between the value of the high-frequency power supplied to the vibrator and the amount of oil-containing scum to be treated. If the output is greater than 600 W, the quality of the separated water (oil-containing wastewater) decreases. On the other hand, if the output is less than 400 W, the treatment time becomes longer. Based on these research results, in this embodiment, the amount of oil-containing scum is set to 20 L to 30 L, preferably 30 L, and the high-frequency power supplied to the vibrator is set to 400 W to 600 W, preferably 600 W. In other words, the oscillator supplies the vibrator with high-frequency power of 20 W to 30 W, preferably 20 W per 1 L of oil-containing scum. This makes it possible to more effectively separate water (oil-containing wastewater) and garbage from the oil-containing scum.

According to a further embodiment of the oil-containing wastewater separation device of the present invention, it further includes a temperature regulator capable of adjusting the temperature of the oil-containing scum to 10°C or higher and 40°C or lower.

After extensive research, the inventors discovered that if the temperature of the oil-containing scum is too low, the viscosity of the oil-containing scum increases, causing clogging and other problems when processing the oil-containing scum after separation (volume reduction), and that if the temperature of the oil-containing scum is too high, the separation effect improves, but the concentrated (volume-reduced) oil-containing scum and floating oil become more soluble in the oil-containing wastewater due to the effects of ultrasound, reducing the separation effect. Based on these research results, the present invention is configured to adjust the temperature of the oil-containing scum to between 10°C and 40°C. This allows water (oil-containing wastewater) and garbage to be separated more effectively from the oil-containing scum.

According to a preferred embodiment of the oil-containing wastewater separation method of the present invention, there is provided a method for reducing the volume of oil-containing scum, which comprises: (a) storing oil-containing scum in a storage tank; (b) arranging a vibrator in the storage tank such that the upper surface of the vibrator is inclined at a predetermined angle relative to the liquid level of the oil-containing scum and there is a space between the vibrator and the bottom surface of the storage tank ; and (c) supplying high-frequency power to the vibrator.

According to the present invention, the ultrasonic waves generated by the vibrator generate fine bubbles in the oil-containing scum, and cavitation can be actively performed by the change in sound pressure. As a result, the impact pressure generated when the fine bubbles attached to the oil-containing scum disappear (collapse) can effectively separate water (oil-containing wastewater) and dust from the oil-containing scum. Since the upper surface of the vibrator is inclined at a predetermined angle with respect to the liquid surface of the oil-containing scum, the water (oil-containing wastewater) separated from the oil-containing scum does not remain on the upper surface. In other words, the oil-containing scum can always be present on the upper surface of the vibrator, so that the separation of water (oil-containing wastewater) and dust from the oil-containing scum by the cavitation effect can be promoted. In addition, since the upper surface of the vibrator is only inclined at a predetermined angle with respect to the liquid surface of the oil-containing scum, the water (oil-containing wastewater) and dust can be separated from the oil-containing scum with a space-saving and simple structure. In addition, according to the present invention, the water (oil-containing wastewater) separated from the oil-containing scum flows into the space between the vibrator and the bottom surface, and the oil-containing scum can be moved to the upper surface side of the vibrator by the convection effect. In addition, the vibrator can be effectively prevented from being submerged in the water (oil-containing wastewater) separated from the oil-containing scum, which further promotes the separation of the water (oil-containing wastewater) and dirt from the oil-containing scum by the cavitation effect.

According to a further embodiment of the oil-containing wastewater separation method of the present invention, step (b) includes a step of placing the transducer in the storage tank so that the upper surface is inclined at an angle of 15 degrees to 25 degrees, preferably about 20 degrees, relative to the liquid surface.

After extensive research, the inventors have found that the reduction rate of oil-containing scum is high when the inclination angle of the top surface of the vibrator with respect to the liquid surface is 15 degrees or more and 25 degrees or less, preferably about 20 degrees. Here, the reduction rate is defined as the value obtained by subtracting the "volume of the oil-containing scum after volume reduction (after processing) in the storage tank" from the "volume of the oil-containing scum before volume reduction (before processing) in the storage tank" by the "volume of the oil-containing scum before volume reduction (before processing) in the storage tank", and then multiplying the result by 100. Based on these research results, in this embodiment, the inclination angle of the top surface of the vibrator with respect to the liquid surface is set to 15 degrees or more and 25 degrees or less, preferably about 20 degrees. This can further promote the volume reduction of the oil-containing scum.

According to a further embodiment of the oil-containing wastewater separation method of the present invention, step (b) includes a step of placing the transducer in the storage tank so that the distance between the liquid level and the part of the upper surface closest to the liquid level is 5 cm or more.

After extensive research, the inventors discovered that if the distance between the top surface of the vibrator and the surface of the oil-containing scum is small, the surface of the oil-containing scum vibrates violently, causing the oil-containing scum separated by the effects of ultrasound to instantly remix. Based on these research results, in this embodiment, the distance between the top surface of the vibrator and the surface of the oil-containing scum is set to 5 cm or more. This makes it possible to prevent a decrease in the volume reduction effect of the oil-containing scum.

According to the present invention, when separating oil-containing wastewater from oil-containing scum, it is possible to achieve both improved processing efficiency and space saving.

1 is a schematic diagram showing the configuration of an oil-containing wastewater separation apparatus 1 according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the experimental results regarding the relationship between the amount of oil-containing scum (Scoil), the reduction rate of the oil-containing scum (Scoil), and the amount of oil in the oil-containing wastewater (Woil) (separated water). FIG. 13 is an explanatory diagram showing the experimental results regarding the relationship between the ultrasonic frequency output to the oil-containing scum coil and the reduction rate. FIG. 13 is an explanatory diagram showing experimental results regarding the relationship between the output of the ultrasonic oscillator 8 and the reduction rate. 1 is an explanatory diagram showing the experimental results regarding the relationship between the inclination angle of the upper surface 4a of the ultrasonic transducer 4 with respect to the liquid level of the oil-containing scum Scoil and the rate of change. FIG. FIG. 1 is a schematic diagram showing the configuration of a modified oil-containing wastewater separation apparatus 1A. FIG. 1 is a schematic diagram showing the configuration of a modified oil-containing wastewater separation apparatus 1B.

Next, the best mode for carrying out the present invention will be explained using examples.

As shown in FIG. 1, the oil-containing wastewater separation device 1 according to this embodiment includes a storage tank 2 capable of storing oil-containing scum, an ultrasonic transducer 4 disposed in the storage tank 2, a mounting table 6 disposed in the storage tank 2 on which the ultrasonic transducer 4 can be placed, an ultrasonic oscillator 8 electrically connected to the ultrasonic transducer 4 via a power line L so as to supply high-frequency power to the ultrasonic transducer 4, and a temperature regulator 30 for regulating the temperature of the oil-containing scum in the storage tank 2.

As shown in FIG. 1, the bottom wall 2a of the storage tank 2 has a tapered shape. In other words, the bottom wall 2a has a shape that becomes deeper toward the center. A valved discharge pipe 10 is connected to approximately the center of the bottom wall 2a. That is, the valved discharge pipe 10 is connected to the deepest part of the storage tank 2. A valved discharge pipe 12 is connected to the side wall 2b of the storage tank 2. The valved discharge pipe 12 is disposed at a position on the side wall 2b closer to the bottom wall 2a, preferably adjacent to the bottom wall 2a. Oil-containing scum Scoil pumped up by a pump P from an oil-water separation tank 90 is supplied to the storage tank 2 through a hose H. The oil-water separation tank 90 is a device that separates waste liquid and wastewater generated in, for example, a metal processing factory into floating oil Foil, oil-containing scum Scoil, oil-containing wastewater Woil, and sludge Slg.

The ultrasonic transducer 4 is made of, for example, piezoelectric ceramics, and has the property of expanding and contracting when an AC voltage is applied. That is, the ultrasonic transducer 4 converts electrical energy into mechanical energy, more specifically, converts high-frequency power supplied from the ultrasonic oscillator 8 into mechanical vibration to generate ultrasonic waves. In this embodiment, the ultrasonic transducer 4 is configured as a immersion type transducer that is submerged in the storage tank 2. The ultrasonic transducer 4 has an approximately rectangular parallelepiped shape.

As shown in FIG. 1, the mounting table 6 is configured as a lattice-shaped platform having a predetermined height, and can be installed in the storage tank 2 by hooking it onto the upper edge of the storage tank 2. The mounting table 6 also has a mounting surface 6a on which the ultrasonic transducer 4 can be placed. The mounting surface 6a has an inclination angle of about 20 degrees with respect to the liquid level of the oil-containing scum Scoil stored in the storage tank 2. By placing the ultrasonic transducer 4 on the mounting surface 6a, the upper surface 4a of the ultrasonic transducer 4 also has an inclination angle of about 20 degrees with respect to the liquid level of the oil-containing scum Scoil stored in the storage tank 2. The height of the mounting table 6 is set so that the distance between the part of the upper surface 4a of the ultrasonic transducer 4 placed on the mounting surface 6a that is closest to the liquid level of the oil-containing scum Scoil and the liquid level of the oil-containing scum Scoil is 5 cm or more. Since the ultrasonic transducer 4 is placed on the mounting surface 6a of the mounting table 6, a predetermined space R is formed between the ultrasonic transducer 4 and the bottom wall 2a of the storage tank 2. In this embodiment, the mounting table 6 is a lattice-shaped platform, but it goes without saying that any structure is acceptable as long as the ultrasonic transducer 4 can be placed with the upper surface 4a of the ultrasonic transducer 4 at an inclination angle with respect to the liquid surface of the oil-containing scum (Scoil) stored in the storage tank 2.

The temperature regulator 30 has a heater (not shown), a switch (not shown) that can switch on and off the current passing through the heater, a temperature sensor (not shown) that measures the temperature of the oil-containing scum Scoil stored in the storage tank 2, and a control device (not shown) that controls the switch based on the temperature measured by the temperature sensor. The control device compares the measured temperature with the temperature of the oil-containing scum Scoil stored in the storage tank 2, and controls the switch so that the temperature of the oil-containing scum Scoil is maintained at the desired temperature.

Next, the operation of the oil-containing wastewater separation device 1 according to the embodiment of the present invention thus constructed will be described. First, with the mounting table 6 and ultrasonic transducer 4 placed in the storage tank 2, oil-containing scum Scoil is supplied from the oil-water separation tank 90 into the storage tank 2 until the amount of oil-containing scum Scoil in the storage tank 2 reaches about 30 L. At this time, the upper surface 4a of the ultrasonic transducer 4 has an inclination angle of about 20 degrees with respect to the liquid level of the oil-containing scum Scoil. In addition, the distance between the part of the upper surface of the ultrasonic transducer 4 closest to the liquid level of the oil-containing scum Scoil and the liquid level of the oil-containing scum Scoil is set to be 5 cm or more. Furthermore, a predetermined space R is formed between the ultrasonic transducer 4 and the bottom wall 2a of the storage tank 2.

Then, the temperature of the oil-containing scum Scoil is set to 10°C or higher and 40°C or lower by the temperature regulator 30, and in this state, high-frequency power is supplied from the ultrasonic oscillator 8 to the ultrasonic vibrator 4. Here, in this embodiment, the high-frequency power supplied from the ultrasonic oscillator 8 to the ultrasonic vibrator 4 is set to an output of 600 W (i.e., the ultrasonic oscillator 8 is configured to supply 20 W of high-frequency power per 1 L of oil-containing scum Scoil to the ultrasonic vibrator 4), and the ultrasonic frequency output to the oil-containing scum Scoil is set to 40 kHz.

When ultrasonic vibration is applied to the oil-containing scum coil in the storage tank 2, oil-containing wastewater Woil (separated water) is separated from the oil-containing scum coil, and the oil-containing scum coil with a relatively low specific gravity moves to the top of the storage tank 2, while the oil-containing wastewater Woil (separated water) with a relatively high specific gravity moves to the bottom of the storage tank 2. Here, the separation of the oil-containing wastewater Woil (separated water) from the oil-containing scum coil is performed by the following mechanism. That is, by applying ultrasonic vibration to the oil-containing scum coil, fine bubbles are generated in the oil-containing scum coil, and cavitation can be actively caused by changes in sound pressure. As a result, the impact pressure generated when the fine bubbles attached to the oil-containing scum coil disappear (collapse) effectively separates the oil-containing wastewater Woil (separated water) and garbage from the oil-containing scum coil.

In addition, since the upper surface 4a of the ultrasonic transducer 4 has an inclination angle of 20 degrees with respect to the liquid surface of the oil-containing scum Scoil, the oil-containing wastewater Woil (separated water) separated from the oil-containing scum Scoil does not remain on the upper surface 4a. In other words, the oil-containing scum Scoil can always be present on the upper surface 4a of the ultrasonic transducer 4. In addition, the oil-containing wastewater Woil (separated water) that flows down the upper surface 4a flows into the space R between the ultrasonic transducer 4 and the bottom wall 2a of the storage tank 2, and the oil-containing scum Scoil present in the space R can be moved upward in the storage tank 2 by the convection effect. Furthermore, since the ultrasonic transducer 4 is elevated by the mounting stand, it is possible to effectively prevent the ultrasonic transducer 4 from being buried in the oil-containing wastewater Woil (separated water) separated from the oil-containing scum Scoil. This can promote the separation of oil-containing wastewater Wool (separated water) and debris from the oil-containing scum (Scoil) through the cavitation effect.

The distance between the part of the upper surface of the ultrasonic vibrator 4 closest to the liquid surface of the oil-containing scum Scoil and the liquid surface of the oil-containing scum Scoil is set to be 5 cm or more, so that the occurrence of violent vibrations near the liquid surface of the oil-containing scum Scoil can be prevented. This makes it possible to suppress a decrease in the volume reduction effect of the oil-containing scum Scoil.

In addition, the amount of oil-containing scum Scoil is set to 30 L, the oil temperature of the oil-containing scum Scoil is set to 10°C or higher and 40°C or lower, the ultrasonic frequency output to the oil-containing scum Scoil is set to 40 kHz, and the output of the ultrasonic oscillator 8 is set to 600 W, which further promotes the separation of oil-containing wastewater (separated water) and garbage from the oil-containing scum Scoil.

After the oil-containing wastewater Woil (separated water) is separated from the oil-containing scum Scoil in the storage tank 2 in this manner, the oil-containing wastewater (separated water) can be discharged by opening the valved discharge pipe 10, and the reduced-volume oil-containing scum Scoil can be discharged by opening the valved discharge pipe 12.

Figure 2 is an explanatory diagram showing the experimental results regarding the relationship between the amount of oil-containing scum scoil, the reduction rate of the oil-containing scum scoil, and the amount of oil in the oil-containing wastewater Woil (separated water); Figure 3 is an explanatory diagram showing the experimental results regarding the relationship between the ultrasonic frequency output to the oil-containing scum scoil and the reduction rate; Figure 4 is an explanatory diagram showing the experimental results regarding the relationship between the output of the ultrasonic oscillator 8 and the reduction rate; and Figure 5 is an explanatory diagram showing the experimental results regarding the relationship between the inclination angle of the upper surface 4a of the ultrasonic vibrator 4 relative to the liquid level of the oil-containing scum scoil and the rate of change.

The relationship between the amount of oil-containing scum Scoil and the reduction rate of oil-containing scum Scoil shows a tendency for the reduction rate to decrease as the amount of oil-containing scum Scoil increases, as shown in Figure 2. Here, the reduction rate is defined as the reduction rate of the volume due to the removal of oil-containing wastewater Woil (separated water) from the oil-containing scum Scoil, and specifically, it is defined as the value obtained by subtracting the "volume of the oil-containing scum after volume reduction (after treatment) in storage tank 2" from the "volume of the oil-containing scum before volume reduction (before treatment) in storage tank 2" by the "volume of the oil-containing scum before volume reduction (before treatment) in storage tank 2", and then multiplying the result by 100. Here, the amount of oil in the oil-containing wastewater Woil (separated water) (normal hexane extract mass, hereafter referred to as "n-Hex" in mg/L) indicates that the larger the value, the more oil is dissolved in the oil-containing wastewater Woil (separated water), and the worse the water quality. When the amount of oil-containing scum Scoil was 45 L, both the reduction rate and n-Hex showed the smallest values, but the treatment effect was unstable and the treatment time was long. Based on the above results, in this embodiment, the amount of oil-containing scum Scoil is set to 20 L or more and 30 L or less, preferably 30 L.

As shown in Figure 3, the relationship between the ultrasonic frequency output to the oil-containing scum coil and the reduction rate shows that the highest reduction rate is observed around 40 kHz. Based on these results, in this embodiment, the ultrasonic frequency output to the oil-containing scum coil is set to 20 kHz or more and 100 kHz or less, preferably about 40 kHz.

As shown in FIG. 4, the relationship between the output of the ultrasonic oscillator 8 and the reduction rate shows that the reduction rate is greatest when the output is 600 W. If the output is greater than 600 W, the quality of the separated oil-containing wastewater Woil (separated water) decreases, and if the output is less than 400 W, the processing time becomes longer. From the above results, in this embodiment, the output of the ultrasonic oscillator 8 is set to 400 W or more and 600 W or less, preferably 600 W. That is, the ultrasonic oscillator 8 is configured to supply high-frequency power of 20 W or more and 30 W or less, preferably 20 W per 1 L of oil-containing scum scoil to the ultrasonic vibrator 4. When the ultrasonic frequency output to the oil-containing scum scoil is set to 40 kHz and the output of the ultrasonic oscillator 8 is set to 600 W, the reduction rate was 39% on average.

As shown in FIG. 5, the relationship between the inclination angle of the upper surface 4a of the ultrasonic transducer 4 relative to the liquid surface of the oil-containing scum Scoil and the rate of change shows the largest value at an inclination angle of approximately 17.5 degrees. Here, the rate of change is defined as the increase or decrease in the reduction rate when the inclination angle of the upper surface 4a of the ultrasonic transducer 4 relative to the liquid surface of the oil-containing scum Scoil is set to 0 degrees, which is 1. From the above results, in this embodiment, the inclination angle of the upper surface 4a of the ultrasonic transducer 4 relative to the liquid surface of the oil-containing scum Scoil is set to 15 degrees or more and 25 degrees or less, preferably approximately 20 degrees.

According to the oil-containing wastewater separation device 1 of the present invention according to the present embodiment described above, the ultrasonic vibrator 4 is simply installed in the storage tank 2 so that the upper surface 4a of the ultrasonic vibrator 4 has an inclination angle of 20 degrees with respect to the liquid surface of the oil-containing scum scoil, so that the oil-containing wastewater Woil (separated water) and garbage can be separated from the oil-containing scum scoil with a space-saving and simple structure. Moreover, since the upper surface 4a is inclined with respect to the liquid surface of the oil-containing scum scoil, the oil-containing wastewater Woil (separated water) separated from the oil-containing scum scoil does not remain on the upper surface 4a. In other words, since the oil-containing scum scoil always exists on the upper surface 4a of the ultrasonic vibrator 4, the separation of the oil-containing wastewater Woil (separated water) and garbage from the oil-containing scum scoil by the cavitation effect can be promoted. As a result, it is possible to reduce the volume of oil-containing scum (Scoil) at low cost and also reduce the amount of industrial waste generated, which contributes to reducing industrial waste treatment costs.

In addition, according to the oil-containing wastewater separation device 1 of the present invention in this embodiment, since there is a space R between the ultrasonic vibrator 4 and the bottom wall 2a of the storage tank 2, the oil-containing wastewater Woil (separated water) that flows down the upper surface 4a flows into the space R, and the oil-containing scum Scoil that is retained in the space R can be moved to the top of the storage tank 2 by the convection effect. This can promote the separation of the oil-containing wastewater Woil (separated water) and garbage from the oil-containing scum Scoil by the cavitation effect.

Furthermore, according to the oil-containing wastewater separation device 1 of the present invention in this embodiment, the distance between the part of the upper surface of the ultrasonic vibrator 4 closest to the liquid surface of the oil-containing scum Scoil and the liquid surface of the oil-containing scum Scoil is set to be 5 cm or more, so that the occurrence of violent vibrations on the liquid surface of the oil-containing scum Scoil can be prevented. This makes it possible to suppress a decrease in the volume reduction effect of the oil-containing scum Scoil.

In addition, according to the oil-containing wastewater separation device 1 of the present invention in this embodiment, the amount of oil-containing scum scoil is set to 30 L, the temperature of the oil-containing scum scoil is set to 10°C or more and 40°C or less, and the ultrasonic frequency output to the oil-containing scum scoil is set to 40 kHz, and the output of the ultrasonic oscillator 8 is set to 600 W. This makes it possible to suppress inconveniences such as the oil-containing scum scoil becoming difficult to process after volume reduction due to its high viscosity, the oil-containing scum scoil and floating oil after volume reduction being dissolved in the oil-containing wastewater wool due to the effect of ultrasonic waves, reducing the separation effect, or the water quality of the separated oil-containing wastewater (separated water) deteriorating. This makes it possible to more effectively separate the oil-containing wastewater wool (separated water) and garbage from the oil-containing scum scoil.

In this embodiment, the ultrasonic vibrator 4 is placed on the mounting surface 6a of the mounting table 6, so that the upper surface 4a is inclined at about 20 degrees relative to the liquid level of the oil-containing scum Scoil, and a space R is provided between the ultrasonic vibrator 4 and the bottom wall 2a of the storage tank 2, but this is not limited to the above. For example, as illustrated in the modified oil-containing wastewater separation device 1A shown in Figure 6, by lifting one end of the ultrasonic vibrator 4, the upper surface 4a may be inclined at about 20 degrees relative to the liquid level of the oil-containing scum Scoil, and a space R may be provided between the ultrasonic vibrator 4 and the bottom wall 2a of the storage tank 2.

In this embodiment, the upper surface 4a of the ultrasonic transducer 4 is inclined at approximately 20 degrees relative to the liquid surface of the oil-containing scum (Scoil), but any inclination angle between 15 degrees and 25 degrees may be used.

In this embodiment, the storage tank 2 stores 30 L of oil-containing scum scoil, and the high-frequency power supplied from the ultrasonic oscillator 8 to the ultrasonic transducer 4 is 600 W, but this is not limited to this. For example, the storage tank 2 may store 20 L to 30 L of oil-containing scum scoil, and supply 400 W to 600 W of high-frequency power to the ultrasonic transducer 4, i.e., the ultrasonic oscillator 8 may supply 20 W to 30 W of high-frequency power to the ultrasonic transducer 4 per 1 L of oil-containing scum scoil.

In this embodiment, the ultrasonic frequency output to the oil-containing scum coil is 40 kHz, but any frequency between 20 kHz and 100 kHz can be used.

In this embodiment, the upper surface 4a of the ultrasonic vibrator 4 is inclined relative to the liquid surface of the oil-containing scum Scoil, but this is not limited to this. For example, as shown in the modified oil-containing wastewater separation device 1B illustrated in FIG. 7, the ultrasonic vibrator 4 may be placed in a raised state on the mounting table 6B without inclining the upper surface 4a of the ultrasonic vibrator 4 relative to the liquid surface of the oil-containing scum Scoil.

In this embodiment, the oil-containing scum coil is heated by a dedicated heater, but this is not limited to the above. Instead of a dedicated heater, the oil-containing scum coil may be heated by heat generated by a device arranged in a position where heat can be transferred to the oil-containing scum coil, such as an ultrasonic vibrator 4.

In this embodiment, the temperature regulator 30 has a heater, a switch, a temperature sensor, and a control device, and is configured to control the switch so that the temperature of the oil-containing scum Scoil is maintained at a desired temperature, but this is not limited to the above. For example, the temperature regulator 30 may further have a cooler and a second switch that can interrupt the current flowing through the cooler, and may be configured to control the switch and the second switch so that the temperature of the oil-containing scum Scoil is maintained at a desired temperature.

This embodiment shows an example of a form for implementing the present invention. Therefore, the present invention is not limited to the configuration of this embodiment.

1. Oil-containing wastewater separation equipment (oil-containing wastewater separation equipment)
1A Oil-containing wastewater separation device (oil-containing wastewater separation device)
1B Oil-containing wastewater separation device (oil-containing wastewater separation device)
2. Storage tank (storage tank)
2a Bottom wall (bottom surface)
2b Side wall 4 Ultrasonic transducer (transducer)
4a Top surface (top surface)
6 Mounting table 6B Mounting table 6a Mounting surface 8 Ultrasonic oscillator (oscillator)
10 Discharge pipe with valve 12 Discharge pipe with valve 90 Oil-water separator 30 Temperature regulator (temperature regulator)
L Power line Scoil Oil-containing scum (oil-containing scum)
H Hose P Pump Foil Floating oil Woil Oil-containing wastewater Slg Sludge R Space

Claims (10)

An oil-containing wastewater separation apparatus for reducing the volume of oil-containing scum,
a storage tank having a bottom surface and capable of storing the oil-containing scum;
a vibrator having an upper surface facing the liquid surface of the oil-containing scum, the upper surface being inclined at a predetermined angle with respect to the liquid surface and having a space between the upper surface and the bottom surface ;
an oscillator electrically connected to the vibrator so as to be able to supply high frequency power to the vibrator;
An oil-containing wastewater separation device comprising: 2. The oil-containing wastewater separation apparatus according to claim 1, wherein the upper surface has an inclination angle of 15 degrees to 25 degrees, preferably about 20 degrees, relative to the liquid surface. The oil-containing wastewater separation apparatus according to claim 1 or 2, wherein the vibrator is arranged in the storage tank so that a distance between the liquid level and a part of the upper surface closest to the liquid level is 5 cm or more. 4. The oil-containing wastewater separation apparatus according to claim 1, wherein the ultrasonic frequency output to the oil-containing scum is 20 kHz or more and 100 kHz or less, preferably about 40 kHz. The oil-containing scum stored in the storage tank is 20 L or more and 30 L or less, preferably 30 L,
The oil-containing wastewater separation apparatus according to any one of claims 1 to 4 , wherein the high-frequency power is 400 W or more and 600 W or less, preferably 600 W. The oil-containing wastewater separation apparatus according to any one of claims 1 to 5 , wherein the oscillator supplies the vibrator with high-frequency power of 20 W or more and 30 W or less, preferably 20 W, per 1 L of the oil-containing scum. The oil-containing wastewater separation apparatus according to any one of claims 1 to 6 , further comprising a temperature regulator capable of adjusting the temperature of the oil-containing scum to 10°C or higher and 40°C or lower. A method for separating oil-containing wastewater for reducing the volume of oil-containing scum, comprising:
(a) storing the oil-containing scum in a storage tank;
(b) arranging an oscillator in the storage tank such that the upper surface is inclined at a predetermined angle with respect to the liquid level of the oil-containing scum and such that there is a space between the oscillator and a bottom surface of the storage tank ;
(c) A method for separating oil-containing wastewater, comprising: supplying high-frequency power to the vibrator. The oil-containing wastewater separation method described in claim 8, wherein step (b) includes a step of placing the transducer in the storage tank so that the upper surface is inclined at an angle of 15 degrees or more and 25 degrees or less, preferably about 20 degrees, relative to the liquid level. The oil-containing wastewater separation method described in claim 8 or 9, wherein step (b) includes a step of placing a vibrator in the storage tank so that the distance between the part of the upper surface closest to the liquid level and the liquid level is 5 cm or more.

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