JP2013138647A - Waste water purification apparatus for hydroponic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water purification apparatus for hydroponic systems, inexpensive and excellent in maintainability.SOLUTION: In the waste water purification apparatus, a hydroponic system (10) thereof includes a cultivation bed (101) for planting plants, an introduction pipe (52) for introducing a nutrient solution to the cultivation bed (101), a discharge pipe (53) for discharging the nutrient solution out of the system (10) as a waste solution, and a waste solution purification unit (60) for purifying the waste solution. The waste solution purification unit (60) has a discharge unit (62) for generating discharge in the waste solution and an ultrasonic wave generating unit (94) for irradiating the waste solution with ultrasonic waves. The discharge unit (62) is constituted to comprise an electrode pair (64, 65, 464, 465, 564, 565, 664, 665) for generating discharge for generating hydrogen peroxide through hydroxy radicals in the waste solution, and a power source unit (70), and the ultrasonic wave generating unit (94) is constituted so as to convert hydrogen peroxide in the waste solution to hydroxy radicals.

Description

  It is related with the technical field regarding the waste liquid purification apparatus of a hydroponic cultivation system.

  DESCRIPTION OF RELATED ART Conventionally, what uses granular activated carbon is known as a processing apparatus of the nutrient solution used for the hydroponics of a plant (for example, refer patent document 1). In this apparatus, growth-inhibiting substances such as phenolic substances and organic acid substances secreted from cultivated plants are adsorbed and removed by granular activated carbon. When granular activated carbon is used, a filtration filter is used to prevent the granular activated carbon from leaking into the nutrient solution.

JP-A-8-266171

  By the way, it is necessary to replace the nutrient solution used in hydroponics regularly. At that time, if the nutrient solution is discharged into a general river, the growth promoting substances contained in the nutrient solution, There is a problem that the growth inhibitory substances (chemical substances) described above flow into rivers and the like and adversely affect plant ecosystems.

  Therefore, it is conceivable to perform a purification process before the nutrient solution is discharged to a river or the like by providing a processing apparatus shown in Patent Document 1 in a discharge pipe for discharging the nutrient solution to the outside of the system.

  However, in this case, since it is necessary to replace the filter frequently, there is a problem that labor and cost for replacing the filter increase.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the waste liquid purification apparatus of the hydroponic cultivation system which was low-cost and excellent in maintainability.

  A first aspect of a waste liquid purification apparatus according to the present invention is directed to a waste liquid purification apparatus of a hydroponic cultivation system (10). The hydroponic cultivation system (10) includes a cultivation bed (101) for planting a plant and a cultivation bed. (101) An introduction pipe (52) for introducing the nutrient solution, a discharge pipe (53) for discharging the nutrient solution as waste liquid outside the system (10), and a waste liquid purification unit (60 The waste liquid purification unit (60) includes a discharge part (62) that discharges in the waste liquid and an ultrasonic generation part (94) that irradiates the waste liquid with ultrasonic waves, and the discharge part (62) Has an electrode pair (64, 65, 464, 465, 564, 565, 664, 665) that generates discharge in the waste liquid and a power supply unit (70) that applies voltage to the electrode pair (64, 65, 464, 465, 564, 565, 664, 665). However, it is configured to generate hydroxyl radicals in the waste liquid by electric discharge, and the ultrasonic generator (94) changes the generated hydroxyl radicals. It is configured to convert hydrogen peroxide in the waste liquid produced by the conversion into hydroxyl radicals.

  As a second aspect, a control unit (103) for controlling the operation and stop of the discharge unit (62) and the ultrasonic wave generation unit (94) is further provided, and the control unit (103) is provided in the waste liquid purification tank (61). The operation and stop of the discharge unit (62) and the ultrasonic wave generation unit (94) may be controlled so that the concentration of hydrogen peroxide contained in the waste liquid is within a predetermined range.

  In this case, the control unit (103) keeps the discharge unit (62) in an operating state until the concentration of hydrogen peroxide contained in the waste liquid in the waste liquid purification tank (61) reaches a preset lower limit value. After the ultrasonic generator (94) is in a stopped state and reaches the lower limit value, the discharge unit (62) and the ultrasonic generator (94) are in the operating state until reaching the upper limit value set in advance. After reaching the lower limit, it is preferable that the discharge part (62) is stopped and the ultrasonic wave generation part (94) is in an operating state until the lower limit is reached.

  In this case, it is preferable to further include a sensor for measuring the concentration of hydrogen peroxide contained in the waste liquid in the waste liquid purification tank (61).

  As a third aspect, the electrode pair (564,565) is configured by plate-like electrodes arranged to face each other, and the power supply unit (70) is a pulse power supply that applies a pulse voltage to the electrode pair (564,565). The discharge unit (62) may include a bubble generation unit (520) that generates bubbles in the waste liquid between the electrode pair (564,565).

  As a 4th aspect, the ion supply part (53,69) which supplies a copper ion or an iron ion in the waste liquid in this discharge pipe (53) may be provided in the discharge pipe (53).

  As a fifth aspect, the waste liquid purification unit is connected to the discharge pipe (53), the waste liquid is stored therein, and the water storage part (61) in which the discharge part (62) is accommodated, and the water storage part (61) The on-off valve (63) arranged on the downstream side and the process of discharging the stored waste liquid out of the water storage section (61) after storing the waste liquid in the water storage section (61) and executing the discharge for a predetermined time Batch processing means (61, 63, 103) to be executed may be provided.

  As a sixth aspect, the waste liquid purification unit may have an adsorbing part (80) that is provided in the vicinity of the upstream side or the downstream side of the discharge part (62) and adsorbs the chemical substance in the waste liquid.

  According to the waste liquid purification apparatus according to the present invention, it is possible to realize a waste liquid purification apparatus for a hydroponic cultivation system that is low in cost and excellent in maintainability.

It is a figure which shows the structure of the hydroponic cultivation system provided with the waste liquid purification | cleaning unit which concerns on Embodiment 1 of this invention. It is a whole block diagram of the waste liquid purification | cleaning unit which concerns on Embodiment 1, and shows the state before starting a waste liquid purification operation. 2 is a perspective view of an insulating casing according to Embodiment 1. FIG. It is a figure which shows the modification of an ultrasonic wave generation part. It is a figure which shows the modification of an ultrasonic wave generation part. It is a block diagram of the discharge part of the waste liquid purification | cleaning unit which concerns on Embodiment 1, and shows the state where the bubble was stabilized during waste liquid purification operation. It is a figure which shows the basic cycle of the process in a waste liquid purification unit. It is a timing chart which shows an example of a drive of a waste liquid purification unit. It is a timing chart which shows an example of a drive of a waste liquid purification unit. It is a block diagram which shows an example of the control part of a waste liquid purification unit. It is a figure which shows the 1st modification of a discharge part. It is a perspective view of the insulation casing in the 1st modification of a discharge part. It is a figure which shows the 2nd modification of a discharge part, and shows the state before starting a waste liquid purification | cleaning operation | movement. It is a figure which shows the 2nd modification of a discharge part, and shows the state where the bubble was stabilized during waste liquid purification | cleaning operation | movement. It is a top view of the cover part of the insulation casing of the 3rd modification of a discharge part. It is a figure which shows the modification of a waste liquid purification tank. It is a figure which shows the waste liquid purification | cleaning unit which concerns on Embodiment 2. FIG. It is a figure which shows the waste liquid purification | cleaning unit which concerns on Embodiment 3. FIG. It is a figure which shows the waste liquid purification | cleaning unit which concerns on Embodiment 4. FIG. It is a figure which shows the modification of a hydroponic cultivation system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

(Embodiment 1)
<overall structure>
FIG. 1 is a diagram showing a configuration of a hydroponic cultivation system (10) according to an embodiment of the present invention. This hydroponics system (10) is used in so-called facility horticulture (for example, a greenhouse) or a plant factory that grows plants using artificial light in a closed environment. As shown in FIG. 1, a hydroponic cultivation system (10) includes a cultivation bed (101), pipes (51, 52, 53), a pump (102), a waste liquid purification unit (60), and a control unit (103). I have.

  This hydroponics system (10) is equipped with the cultivation operation mode which supplies a nutrient solution to a cultivation bed (101), and the waste liquid processing mode which discharges | emits a nutrient solution out of a hydroponics system (10). The operator can set a desired operation mode from an input device (not shown).

  The cultivation floor (101) and the pump (102) are connected to each other by piping (51, 52), and in the cultivation operation mode, a nutrient solution containing nutrients necessary for plant cultivation circulates (solid line in FIG. 1). reference). In the middle of the pipe (51), a discharge pipe (53) is connected. In the waste liquid treatment mode, a used nutrient solution (hereinafter referred to as waste liquid) passes through the discharge pipe (53) and is supplied with a hydroponics system ( 10) It is discharged outside. At the connection between the discharge pipe (53) and the pipe (51), an electrically driven three-way valve (54) for switching the nutrient solution flow path between the cultivation operation mode and the waste liquid treatment mode is provided. The discharge pipe (53) is provided with a waste liquid purification unit (60) for sterilizing and purifying the waste liquid. The waste liquid purification unit (60) and the three-way valve (54) are controlled by the control unit (103).

  The cultivation bed (101) is configured to accumulate a predetermined amount of nutrient solution. A plant (200) is planted on the cultivation floor (101). The planted plant (200) absorbs the nutrient solution stored in the cultivation floor (101) and uses the nutrients in the absorbed nutrient solution. This cultivation bed (101) is provided with an inflow hole through which nutrient solution flows and an outflow hole through which nutrient solution flows out. Pipe (51) is connected to the outflow hole, and pipe (52) is connected to the inflow hole. Yes.

  The waste liquid purification unit (60) generates hydrogen peroxide through hydroxyl radicals in the water by discharge in water (specifically, nutrient solution), and converts the generated hydrogen peroxide into hydroxyl radicals by ultrasonic waves. The nutrient solution is purified. The purification of the nutrient solution is a concept including sterilization of various germs in the solution, decomposition of organic substances that cause generation of dirt existing in the solution, and the like. The configuration of the waste liquid purification unit (60) will be described in detail later. The waste liquid purification unit (60) is provided with an inflow hole through which the nutrient solution flows and an outflow hole through which the nutrient solution flows out, and the inflow hole is connected to the upstream discharge section (53a) of the discharge pipe (53). Moreover, the downstream discharge part (53b) of the discharge pipe (53) is connected to the outflow hole of the waste liquid purification unit (60), and the downstream discharge part (53b) is connected to the hydroponics system (10). It extends to the general river outside.

  The pump (102) is a pump for circulating the nutrient solution. The suction hole of the pump (102) is connected to the outflow hole of the cultivation bed (101) by a pipe (51), and the discharge hole is connected to the inflow hole of the cultivation bed (101) by a pipe (52). The operation state of the pump (102) is controlled by the control unit (103). In the present embodiment, the pipes (51, 52) are resin pipes, and the discharge pipe (53) is a copper pipe that functions as an ion supply unit. The discharge pipe (53) includes a water storage part (consisting of a waste liquid purification tank (61) described later) for temporarily storing waste liquid, an upstream discharge part (53a) upstream of the water storage part, and a downstream part. It is comprised by the downstream downstream discharge part (53b).

  The control unit (103) outputs a predetermined control signal (SIG) to the pump (102), the waste liquid purification unit (60), and the three-way valve (54) to control the operation state (on / off) of the pump (102). Then, the operation state of the waste liquid purification unit (60) (ON / OFF of the discharge part and the ultrasonic wave generation part) is controlled and the three-way valve (54) is opened and closed.

<Configuration of waste liquid purification unit (60)>
FIG. 2 is a diagram showing a configuration example of the waste liquid purification unit (60). The waste liquid purification unit (60) generates hydrogen peroxide through hydroxyl radicals in the water by discharge in water, and converts the generated hydrogen peroxide into hydroxyl radicals by ultrasonic waves. A used nutrient solution (hereinafter referred to as waste liquid) is purified by the generated hydrogen peroxide and hydroxyl radical. The waste liquid purification unit (60) of this embodiment includes a waste liquid purification tank (61), a discharge section (62), an ultrasonic generation section (94), an electrically driven on-off valve (63), and a copper plate ( 69).

  As described above, the waste liquid purification tank (61) is connected to the upstream discharge portion (53a) and the downstream discharge portion (53b) of the discharge pipe (53).

  The on-off valve (63) is disposed near the downstream side of the waste liquid purification tank (61) in the discharge pipe (53). The discharge part (62) and the on-off valve (63) are controlled by the control part (103).

  The discharge unit (62) includes an electrode pair (64, 65) including a first electrode (64) and a second electrode (65), and a power supply unit (70) for applying a voltage to the electrode pair (64, 65). And an insulating casing (71) for accommodating the first electrode (64) therein.

  The electrode pair (64, 65) is for causing discharge in water. The first electrode (64) is disposed inside the insulating casing (71). The 1st electrode (64) is formed in the shape of a flat plate up and down. The first electrode (64) is connected to the positive electrode side of the power supply section (70). The first electrode (64) is made of a conductive metal material such as stainless steel or copper.

  The second electrode (65) is disposed outside the insulating casing (71). The second electrode (65) is provided above the first electrode (64). The second electrode (65) has a flat plate shape in the vertical direction, and is configured in a mesh shape or a punching metal shape having a plurality of through holes (66) in the vertical direction. The second electrode (65) is disposed substantially parallel to the first electrode (64). The second electrode (65) is connected to the negative electrode side of the power supply unit (70). The second electrode (65) is made of a conductive metal material such as stainless steel or brass.

  The power supply unit (70) applies a predetermined voltage to the electrode pair (64, 65). The power supply unit (70) may be a pulse power supply that repeatedly applies a high voltage instantaneously to the electrode pair (64, 65), but is always several kilovolts for the electrode pair (64, 65). A direct current power source that applies the voltage of may be used. In the case of a DC power supply, the negative electrode side to which the second electrode (65) is connected in the power supply section (70) may be connected to the ground. The power supply unit (70) is provided with a constant power control unit (not shown) that controls the discharge power of the electrode pair (64, 65) to be constant. The power supply unit (70) may be a pulse power supply that repeatedly applies a high voltage to the electrode pair (64, 65) instantaneously. When the power supply unit (70) is a DC power supply, it is possible to reduce the sound at the time of discharge compared to when the power supply unit (70) is a pulse power supply.

  The insulating casing (71) is installed at the bottom of the waste liquid purification tank (61). The insulating casing (71) is made of an insulating material such as ceramics. The insulating casing (71) has a container-like case body (72) whose one surface (upper surface) is open, and a plate-like lid (73) that closes the open portion above the case body (72). doing.

  The case body (72) has a square cylindrical side wall (72a) and a bottom (72b) that closes the bottom of the side wall (72a). The first electrode (64) is laid on the upper side of the bottom (72b). In the insulating casing (71), the vertical distance between the lid (73) and the bottom (72b) is longer than the thickness of the first electrode (64). That is, a predetermined interval is ensured between the first electrode (64) and the lid (73). Thereby, inside the insulating casing (71), a space (S) is formed among the first electrode (64), the case body (72), and the lid portion (73).

  As shown in FIGS. 2 and 3, the opening (74) penetrating the lid (73) in the thickness direction is formed in the lid (73) of the insulating casing (71). The opening (74) allows the formation of an electric field between the first electrode (64) and the second electrode (65). The inner diameter of the opening (74) of the lid (73) is preferably 0.02 mm or more and 0.5 mm or less. The opening (74) as described above constitutes a current density concentration portion that increases the current density of the current path between the electrode pair (64, 65).

  As described above, the insulating casing (71) accommodates only one electrode (first electrode (64)) of the electrode pair (64, 65) inside, and the opening (74) as the current density concentration portion. ).

  In addition, in the opening (74) of the insulating casing (71), the current density of the current path increases, so that water is vaporized by Joule heat and bubbles (B) (see FIG. 6) are formed. That is, the opening (74) of the insulating casing (71) functions as a gas phase forming part that forms bubbles (B) as a gas phase part in the opening (74).

  The ultrasonic wave generator (94) includes a plate-shaped piezoelectric ceramic plate (95) and a pair of metal plates (96a, 96b) provided so as to sandwich the piezoelectric ceramic plate (95). The case (97) enclosing the ultrasonic wave generation unit (94) is sealed and disposed at the bottom of the waste liquid purification tank (61).

  The metal plate (96a, 96b) is supplied with an output signal (AC voltage) of the ultrasonic waveform generator (308) amplified by the amplifier (309). Thereby, the ultrasonic wave generation unit (94) can irradiate the nutrient solution in the waste liquid purification tank (61) with an ultrasonic wave having an arbitrary frequency. However, in order to decompose hydrogen peroxide and efficiently generate hydroxyl radicals, it is preferable that the ultrasonic frequency be about 100 kHz or more.

  In addition, the ultrasonic wave generation part (94) may be installed in arbitrary positions in the range which can irradiate a liquid in a waste liquid purification tank (61) with an ultrasonic wave. For example, as shown in FIG. 4, the ultrasonic generator (94) may be installed outside the bottom of the waste liquid purification tank (61). When the ultrasonic generator (94) is installed outside the bottom of the waste liquid purification tank (61), the ultrasonic waves are transmitted to the nutrient solution via the wall surface of the waste liquid purification tank (61).

  Further, as shown in FIG. 5, the ultrasonic wave generation unit (94) sandwiches a plate-shaped piezoelectric ceramic plate (95) between the upper part of the metal case (97a) and the metal plate (96), and an alternating current therebetween. It may be configured to supply voltage.

  When the nutrient solution is continuously circulated, the concentration of hydrogen peroxide in the waste liquid purification tank (61) flows into the waste solution purification tank (61) more than the discharge portion (62) even when the discharge unit (62) is operated. It may not be high on the side. For this reason, it is preferable to provide the ultrasonic wave generation part (94) on the outflow side with respect to the discharge part (62). However, when the nutrient solution in the waste liquid purification tank (61) is sterilized when the pump (102) is stopped, the ultrasonic wave generation unit (94) is provided on the inflow side from the discharge unit (62). There is no problem.

<Operation of hydroponics system (10)>
In the cultivation operation mode, the hydroponics system (10) operates the pump (102) and controls the three-way valve (54) by the control unit (103) so that the nutrient solution is indicated by a solid line in FIG. Circulate with. Thereby, nutrient solution is supplied to the cultivation floor (101). In the cultivation floor (101), each plant (200) absorbs a necessary amount of nutrient solution. The nutrient solution not absorbed by the plant (200) flows out from the cultivation bed (101) through the pipe (51). The nutrient solution that has flowed out is supplemented with insufficient components and water, and after flowing through the pump (102), flows into the cultivation bed (101) again. The apparatus for adjusting the components and amount of nutrient solution is not shown in FIG. It should be noted that the nutrient solution may be circulated continuously or at an appropriate time interval.

<Operation of waste liquid purification unit>
In the waste liquid treatment mode, the hydroponics system (10) stops the operation of the pump (102) and controls the three-way valve (54) by the control unit (103), so that the nutrient solution is supplied to the two points in FIG. Distribute along the chain line. As a result, the waste liquid is guided to the waste liquid purification unit (60) to be sterilized and purified.

  In the present embodiment, the waste liquid is processed batchwise in the waste liquid purification unit (60). That is, the control unit (103) first closes the on-off valve (63) to block the flow of the waste liquid in the discharge pipe (53) during the waste liquid sterilization / purification process. The control unit (103) executes the sterilization / purification process of the waste liquid for a predetermined time after the first set time T1 has elapsed since the on-off valve (63) is closed, and the on-off valve (63) is opened after the predetermined time has elapsed. open. The controller (103) closes the on-off valve again when the second set time T2 has elapsed since the on-off valve (63) was opened. The control unit (103) repeatedly executes this series of processes. That is, the control unit (103) repeatedly executes the process of storing the waste liquid in the waste liquid purification tank (61) and then sterilizing and purifying it. Here, the first set time T1 can be, for example, a time from when the waste liquid purification tank (61) is empty to when the waste liquid is full. Further, the second set time T2 is, for example, a time that is the same as or slightly shorter than the time until the full waste liquid in the waste liquid purification tank (61) is discharged from the on-off valve (63) to the outside of the tank. It can be.

  At the start of the sterilization / purification process in the waste liquid purification unit (60), as shown in FIG. 2, the space (S) in the insulating casing (71) is in a flooded state. When a predetermined voltage (for example, 1 kV) is applied from the power supply unit (70) to the electrode pair (64, 65), an electric field is formed between the electrode pair (64, 65). At this time, the periphery of the first electrode (64) is covered with the insulating casing (71). For this reason, the leakage current between the electrode pair (64, 65) is suppressed, and the current density of the current path in the opening (74) is increased.

  As the current density in the opening (74) increases, the Joule heat in the opening (74) increases. As a result, in the insulating casing (71), the vaporization of water (waste liquid) is promoted in the vicinity of the opening (74), and bubbles (B) are formed. As shown in FIG. 6, the bubbles (B) cover almost the entire area of the opening (74), and water on the negative electrode side conducting to the second electrode (65) and the first electrode (64) on the positive electrode side. Bubbles (B) are interposed between them. Therefore, in this state, the bubble (B) functions as a resistance that prevents conduction through water between the first electrode (64) and the second electrode (65). Thereby, the leakage current between the first electrode (64) and the second electrode (65) is suppressed, and a desired potential difference is maintained between the electrode pair (64, 65). Then, in the bubble (B), discharge is generated with dielectric breakdown.

  As described above, when discharge is performed with the bubbles (B), hydroxyl radicals are generated in the water in the waste liquid purification tank (61). The generated hydroxyl radicals react rapidly to become hydrogen peroxide. For this reason, the hydrogen peroxide concentration in the waste liquid purification tank (61) gradually increases. When the nutrient solution is irradiated with ultrasonic waves after the hydrogen peroxide concentration has sufficiently increased, the hydrogen peroxide in the nutrient solution is decomposed and hydroxyl radicals are generated again. Hydroxyl radicals generated by ultrasonic irradiation are combined again to return to hydrogen peroxide. For this reason, as shown in FIG. 7, the conversion from hydrogen peroxide to hydroxyl radicals and the conversion from hydroxyl radicals to hydrogen peroxide are circulated. However, since the hydroxyl radical used to purify the nutrient solution such as sterilization is changed to water, the concentration of hydrogen peroxide gradually decreases when the discharge is stopped and only ultrasonic irradiation is performed.

  In order to sufficiently purify the nutrient solution with hydrogen peroxide, the concentration of hydrogen peroxide in the nutrient solution must be increased. Hydrogen peroxide is relatively safe at low concentrations, but it can adversely affect plants at higher concentrations. On the other hand, hydroxyl radicals have a much higher purification capacity than hydrogen peroxide. Therefore, the nutrient solution can be sufficiently purified even at a low concentration. However, the hydroxyl radical is unstable and immediately reacts to become hydrogen peroxide. For this reason, in order to purify the nutrient solution with hydroxyl radicals, the hydroxyl radicals must be continuously generated.

  In the case of electric discharge, water is decomposed and hydroxyl radicals are generated. Therefore, when the operation is continuously performed, the concentration of hydrogen peroxide in the nutrient solution increases more and more. On the other hand, in the case of ultrasonic irradiation, conversion from hydrogen peroxide to hydroxyl radicals occurs, but water does not decompose. For this reason, even if it produces | generates a hydroxyl radical continuously, the density | concentration of hydrogen peroxide does not rise. Therefore, by generating hydrogen peroxide by discharge and generating hydroxyl radicals by ultrasonic waves, purification can be performed much more efficiently than when purification is performed using only discharge. Moreover, since the concentration of hydrogen peroxide can be kept low, a safer purification device can be realized.

  Since the hydroxyl radical is highly reactive, if the hydroxyl radical is in direct contact with the plant (200) cultivated on the cultivation floor (101), the plant (200) may be adversely affected. However, since the lifetime of the hydroxyl radical is very short, the hydroxyl radical hardly exists outside the waste liquid purification tank (61). On the other hand, a low concentration of hydrogen peroxide has little effect on the plant (200). For this reason, by making the waste liquid purification unit (60) independent of the cultivation bed (101), there is an advantage that the plant (200) cultivated on the cultivation bed (101) is not affected by the hydroxyl radical.

  The hydrogen peroxide in the waste liquid convects in the waste liquid purification tank (61) by the heat accompanying the discharge. This promotes diffusion of active species and hydrogen peroxide in water. Further, when the discharge is performed with the bubbles (B), an ion wind is easily generated with the bubbles (B) along with the discharge. Therefore, in the waste liquid purification tank (61), the diffusion effect of active species and hydrogen peroxide can be further improved by using this ion wind.

  And the hydrogen peroxide produced | generated by discharge has the effect | action which disinfects the germs in a waste liquid. Therefore, the waste liquid in the waste liquid purification tank (61) can be sterilized and purified. Hydrogen peroxide is generally safe for plants.

  Also, copper ions are eluted into the waste liquid from the copper discharge pipe (53) and the copper plate (69) in the waste liquid purification tank (61). In the presence of hydrogen peroxide and copper ions, copper ions act catalytically by the Fenton reaction to further promote the generation of hydroxyl radicals. Thereby, the purification efficiency of the waste liquid by a hydroxyl radical improves. In addition, since copper ions have the effect of suppressing the growth of bacteria, the bactericidal action in water also increases.

  In addition, although sterilization and dirt decomposition | disassembly by a waste liquid purification | cleaning unit (60) may be always performed, you may make it perform it at appropriate time intervals. Control of the start and stop of the operation of the waste liquid purification unit (60) may be performed by the control unit (103).

  The discharge part (62) and the ultrasonic wave generation part (94) may be always in an operating state. However, if the hydrogen peroxide concentration in the nutrient solution is low, sufficient hydroxyl radicals can be obtained even if the ultrasonic wave is irradiated. I can not expect the occurrence of. Moreover, if the discharge part (62) is continuously operated, the hydrogen peroxide concentration in the nutrient solution may become too high. For this reason, it is preferable to perform an operation as shown in FIG. First, only the discharge part (62) is operated to raise the hydrogen peroxide in the waste liquid purification tank (61), and then the operation of the ultrasonic wave generation part (94) is started to start the generation of hydroxyl radicals. . Thereafter, when the hydrogen peroxide concentration in the waste liquid purification tank (61) is sufficiently increased, the operation of the discharge unit (62) is stopped, and only the ultrasonic wave generation unit (94) is operated. When the concentration of hydrogen peroxide in the waste liquid purification tank (61) decreases, the operation of the discharge section (62) is started again to increase the concentration of hydrogen peroxide in the waste liquid purification tank (61).

  Although the control as described above may be performed based on a preset timing, the control as shown in FIG. 9 may be performed based on the measured value of the hydrogen peroxide concentration in the waste liquid purification tank (61). . In this case, as shown in FIG. 10, a sensor (307) for measuring the hydrogen peroxide concentration is provided in the waste liquid purification tank (61), and based on the sensor output, the control unit (103) causes the discharge unit (62 ) And the ultrasonic wave generator (94) may be controlled. The control unit (103) may be an arithmetic circuit provided with a central processing unit (CPU). Moreover, although the structure which controls also about a pump (102) was shown, it is good also as a structure which performs control of a pump (102) and control of a discharge part (62) and an ultrasonic wave generation part (94) independently.

  In addition, although the example which starts the driving | operation of an ultrasonic generation part (94) during the driving | operation of a discharge part (62) was shown, operation | movement of an ultrasonic generation part (94) is stopped after driving | operation of a discharge part (62) is stopped. May start. Further, when the discharge unit (62) is re-operated, the ultrasonic wave generation unit (94) may be in a paused state.

<Effect in this embodiment>
As described above, according to the present embodiment, the waste liquid purification unit (60) can purify the waste causative substances in the waste liquid, such as decomposition and sterilization, by using hydroxyl radicals and hydrogen peroxide. It can be sterilized and purified before it flows into the river. Therefore, it is possible to reliably prevent environmental pollution due to the waste liquid. In addition, since a filter or the like is not used, it is advantageous in terms of maintenance and cost.

  In the present embodiment, since the waste liquid is processed batchwise in the waste liquid purification unit (60), the waste liquid is sterilized as compared with the case of processing the waste liquid continuously flowing in the discharge pipe (53).・ The purification effect can be enhanced.

  In FIG. 2, a copper plate (69) (ion supply unit) that partitions the waste liquid purification tank (61) into an upstream side and a downstream side is provided in the waste liquid purification tank (61). A plurality of relatively large through holes (69a) are formed in the copper plate (69). Therefore, the distribution of the waste liquid in the discharge pipe (53) is not hindered by the copper plate (69). Since copper ions are supplied into the waste liquid from the copper plate (69) and the copper discharge pipe (53), copper ions (or iron ions) act catalytically by the Fenton reaction to further promote the generation of hydroxyl radicals. Is done. Thereby, the purification efficiency of the water by a hydroxyl radical further improves. In addition, since copper ions have the effect of suppressing the growth of bacteria, the bactericidal action in water also increases. However, the ion supply unit may not be provided.

<< Variation 1 of the discharge part >>
In Embodiment 1, one opening (74) is formed in the lid part (73) of the insulating casing (71). However, for example, as shown in FIGS. 11 and 12, a plurality of openings (74) may be formed in the lid portion (73) of the insulating casing (71). In this modified example, the lid portion (73) of the insulating casing (71) is formed in a substantially square plate shape, and a plurality of openings (74) are arranged in a grid pattern in the lid portion (73) at equal intervals. Has been. On the other hand, the first electrode (64) and the second electrode (65) are formed in a square plate shape over all the openings (74).

  Also in this modification, each opening (74) functions as a current density concentration part and a gas phase formation part. Thereby, when a voltage is applied to the electrode pair (64, 65) from the power supply unit (70), the current density of each opening (74) increases, and bubbles (B) are formed in each opening (74). . As a result, discharge is generated in each bubble (B), and active species such as hydroxyl radicals and hydrogen peroxide are generated.

<< Second Modification of Discharge Section >>
The discharge part (62) may be configured as follows. As shown in FIG. 13, the discharge part (62) of the modified example 2 is configured as a so-called flange unit type that is inserted and fixed from the outside to the inside of the waste liquid purification tank (61). Moreover, the discharge part (62) of Embodiment 2 has the 1st electrode (64), the 2nd electrode (65), and the insulation casing (71) assembled integrally.

  The insulation casing (71) of Modification 2 has a substantially outer shape that is cylindrical. The insulating casing (71) has a case main body (72) and a lid part (73).

  The case body (72) of Modification 2 is made of an insulating material made of glass or resin. The case body (72) includes a cylindrical base portion (76), a cylindrical wall portion (77) projecting from the base portion (76) toward the waste liquid purification tank (61), and the cylindrical wall portion (77). ) Further protruding from the outer edge portion toward the waste liquid purification tank (61) side. A cylindrical insertion opening (76a) extends in the axial direction in the axial center of the base (76). A cylindrical space (S) that is coaxial with the insertion port (76a) and has a larger diameter than the insertion port (76a) is formed inside the cylindrical wall portion (77).

  The cover part (73) of Embodiment 2 is formed in a substantially disc shape, and is fitted inside the annular convex part (78). The lid (73) is made of a ceramic material. As in the first embodiment, one circular opening (74) penetrating the lid (73) vertically is formed at the axis of the lid (73).

  The first electrode (64) is a vertically long bar-shaped electrode having a circular cross section perpendicular to the axis. The first electrode (64) is fitted in the insertion opening (76a) of the base (76). Thereby, the 1st electrode (64) is accommodated in the inside of an insulation casing (71). In the second embodiment, the end of the first electrode (64) opposite to the waste liquid purification tank (61) is exposed to the outside of the waste liquid purification tank (61). For this reason, the power supply part (70) arrange | positioned outside the waste liquid purification tank (61) and the 1st electrode (64) can be easily connected by electrical wiring.

  The end (64a) on the waste liquid purification tank (61) side of the first electrode (64) faces the space (S) inside the insulating casing (71). In the example shown in FIG. 13, the end (64a) of the first electrode (64) protrudes above the opening surface of the insertion port (76a) (on the waste liquid purification tank (61) side). The distal end surface of the end portion (64a) may be substantially flush with the opening surface of the insertion port (76a), or the end portion (64a) may be recessed below the opening surface of the insertion port (76a). . Moreover, the 1st electrode (64) has ensured the predetermined space | interval between the cover parts (73) which have an opening (74) similarly to Embodiment 1. FIG.

  The second electrode (65) has a cylindrical electrode body (65a) and a flange (65b) projecting radially outward from the electrode body (65a). The electrode body (65a) is externally fitted to the case body (72) of the insulating casing (71). The flange part (65b) constitutes a fixed part that is fixed to the wall part of the waste liquid purification tank (61) and holds the discharge part (62). In a state where the discharge part (62) is fixed to the waste liquid purification tank (61), a part of the electrode body (65a) of the second electrode (65) is submerged.

  The second electrode (65) includes an inner cylindrical portion (65c) having a smaller diameter than the electrode main body (65a) and a connecting portion (between the inner cylindrical portion (65c) and the electrode main body (65a)). 65d). The inner cylinder part (65c) and the connecting part (65d) are immersed in the water in the waste liquid purification tank (61). The inner cylinder part (65c) forms the cylindrical space (67) in the inside. One end of the inner cylinder portion (65c) in the axial direction constitutes a holding portion that contacts the lid portion (73) and holds the lid portion (73). On the other end side in the axial direction of the inner cylindrical portion (65c), a mesh-shaped leakage preventing material (68) is provided so as to cover the cylindrical space (67). The leakage preventing material (68) is substantially grounded by being in contact with the second electrode (65). Thereby, the leakage preventive material (68) prevents leakage from the inside to the outside of the cylindrical space (67) in the space (underwater) inside the waste liquid purification tank (61).

  The second electrode (65) is in a state where a part of the electrode body (65a) is exposed to the outside of the waste liquid purification tank (61). For this reason, a power supply part (70) and a 2nd electrode (65) can be easily connected by electrical wiring.

<Discharge unit operation>
Also in the modification 2, hydrogen peroxide is produced | generated when the discharge part (62) is drive | operated.

  At the start of operation of the discharge part (62), as shown in FIG. 13, the space (S) in the insulating casing (71) is in a flooded state. When a predetermined voltage (for example, 1 kV) is applied from the power supply unit (70) to the electrode pair (64, 65), the current density inside the opening (74) increases.

  When a voltage is continuously applied to the electrode pair (64, 65) from the state shown in FIG. 13, water in the opening (74) is vaporized to form bubbles (B) (see FIG. 14). ). In this state, the bubble (B) covers almost the entire area of the opening (74), and the resistance due to the bubble (B) is between the negative electrode side water in the cylindrical space (67) and the first electrode (64). Is granted. Thereby, the electric potential difference between the 1st electrode (64) and the 2nd electrode (65) is maintained, and discharge occurs with air bubbles (B). As a result, in water, hydrogen peroxide is generated via hydroxyl radicals.

<< Modification 3 of the discharge part >>
Although one opening (74) is formed in the axial center of the disc-shaped lid (73), a plurality of openings (74) may be formed in the lid (73). In the example shown in FIG. 15, five openings (74) are arranged at equal intervals on a virtual pitch circle centered on the axis of the lid (73). Thus, by forming a plurality of openings (74) in the lid (73), it is possible to cause discharges in the vicinity of each opening (74).

  In addition, the power supply part (70) of Embodiment 1 and each modification uses the constant power control part which controls the discharge power of discharge uniformly. However, instead of the constant power control unit, a constant current control unit that controls the discharge current during discharge to be constant may be provided. When this constant current control is performed, the discharge is stabilized regardless of the conductivity of the washing water, so that the occurrence of sparks can be avoided in advance.

  In the first embodiment and each modification, when the power supply unit (70) is a DC power supply, the first electrode (64) is connected to the positive electrode, and the second electrode (65) is connected to the negative electrode of the power supply unit (70). Just connect. However, the first electrode (64) is connected to the negative electrode of the power supply unit (70), the second electrode (65) is connected to the positive electrode of the power supply unit (70), and between the electrode pair (64, 65), So-called negative discharge may be performed. The power supply unit (70) may be an AC power supply or a pulse power supply.

<Deformation example of waste liquid purification tank>
As shown in FIG. 16, an adsorption filter (80) for adsorbing chemical substances in the waste liquid may be provided in the waste liquid purification tank. The adsorption filter (80) is disposed in the vicinity of the downstream side of the discharge part (62). In addition, you may arrange | position an adsorption | suction filter (80) in the upstream vicinity of the discharge part (62).

<Operation of waste liquid purification unit>
In this embodiment, the waste liquid is not processed batchwise by the waste liquid purification unit (60) but continuously. That is, the waste liquid continuously flows through the discharge pipe (53) in the order of the upstream discharge section (53a), the waste liquid purification tank (61), and the downstream discharge section (53b). When the waste liquid passes through the adsorption filter (80) in the waste liquid purification tank (61), the chemical substance in the waste liquid is adsorbed by the adsorption filter (80). Since the discharge part (62) is disposed in the vicinity of the upstream side of the adsorption filter (80), the active species generated by the discharge can be reacted with the chemical substance adsorbed on the adsorption filter (80). Moreover, since the adsorption filter (80) is disposed at a close distance from the discharge part (62), various radicals having a short lifetime can also be used. Therefore, chemical substances in the waste liquid can be reliably decomposed and removed without batch processing the waste liquid. The filter that adsorbs chemical substances does not need to be replaced because the adsorption function is always regenerated by the active species. Therefore, the on-off valve (63) can be eliminated to reduce the cost, and the time required for sterilization and purification of the waste liquid can be shortened. However, an on-off valve may be provided.

(Embodiment 2)
FIG. 17 is a configuration diagram illustrating a waste liquid purification unit (60B) according to the second embodiment. In FIG. 17, the same reference numerals as those in FIG. 2 are assigned to the same configurations as those of the waste liquid purification unit (60) of the first embodiment. Moreover, in FIG. 17, description of a control part (103), an on-off valve (63), etc. is abbreviate | omitted. In the following, differences from the waste liquid purification unit (60) according to the first embodiment will be mainly described.

  The waste liquid purification unit (60B) of the present embodiment includes a waste liquid purification tank (61), a discharge unit disposed in the waste liquid purification tank (61), and an ultrasonic wave generation unit (94). The discharge part has an electrode pair (464, 465) and a power supply part (70) connected to the electrode pair (464, 465). The ultrasonic generator (94) is installed at the bottom of the waste liquid purification tank (61).

  The electrode (464) is housed inside the insulating casing (471a), and the electrode (465) is housed inside the insulating casing (471b). The electrode (464) and the electrode (465) are each formed in a flat plate shape. The electrode (464) and the electrode (465) are made of a conductive metal material such as stainless steel or copper. The power supply unit (70) supplies an alternating voltage of about several kilovolts to the electrode pair (464, 465).

  The insulating casings (471a, 471b) are made of, for example, an insulating material such as ceramics, and have the same configuration as the insulating casing (71) shown in FIG.

  That is, the insulating casing (471a) includes a container-like case main body (480a) whose one surface (the right side surface in FIG. 17) is opened, and a plate-like lid portion (blocking the open portion of the case main body (480a)). 473a). The insulating casing (471b) includes a container-like case main body (480b) whose one surface (left surface in FIG. 17) is opened, and a plate-like lid portion (blocking the open portion of the case main body (480b)). 473b).

  One opening (474a) that penetrates the lid (473a) in the thickness direction is formed in the lid (473a) of the insulating casing (471a). One opening (474b) penetrating the lid portion (473b) in the thickness direction is also formed in the lid portion (473b) of the insulating casing (471b). These openings (474a and 474b) allow formation of an electric field between the electrode (464) and the electrode (465). The inner diameter of the openings (474a, 474b) is preferably 0.02 mm or more and 0.5 mm or less. The openings (474a, 474b) as described above constitute a current density concentration portion that increases the current density of the current path between the electrode pairs (464, 465).

  The insulating casings (471a, 471b) are installed on the side surfaces facing each other in the waste liquid purification tank (61) so that the lid portions (473a, 473b) face each other. In other words, the electrode (464) and the electrode (465) are arranged to face each other.

  In the openings (474a, 474b) of the insulating casings (471a, 471b), the current density in the current path increases, so that the liquid is vaporized by Joule heat and bubbles are formed. That is, the opening (474a, 474b) of the insulating casing (471a, 471b) functions as a gas phase forming part that forms bubbles as a gas phase part in the opening (474a, 474b). With this configuration, when an AC voltage is supplied to the electrode pair (464, 465), discharge can be generated in the bubbles between the electrode pair (464, 465).

  In addition, what is necessary is just to make the specific structure of an ultrasonic wave generation part (94) the same as that of Embodiment 1, and it is preferable to install in the bottom part of a waste liquid purification tank (61), but in a waste liquid purification tank (61) As long as the liquid can be irradiated with ultrasonic waves, it can be installed at any position.

  By adopting the above configuration, even when an AC voltage is supplied to the electrode pair (464, 465), a discharge can be generated between the electrode pair (464, 465), and the concentration of hydrogen peroxide is suppressed while being high. The purification ability can be demonstrated.

  An AC voltage may be applied from the power supply unit (70) to the electrode pair (464, 465), but a discharge can be generated between the electrode pair (464, 465) even if a rectangular wave is applied. .

  Also in the waste liquid purification unit (60B) of this embodiment, it is preferable to perform control as shown in FIG. 8 or FIG.

(Embodiment 3)
FIG. 18 is a configuration diagram showing a waste liquid purification unit (60C) according to Embodiment 3 of the present invention. In FIG. 18, the same reference numerals as those in FIG. 2 are assigned to the same configurations as those of the waste liquid purification unit (60) of the first embodiment. Moreover, in FIG. 18, illustration of a control part (103), an on-off valve (63), etc. is abbreviate | omitted. In the following, differences from the waste liquid purification unit according to the first embodiment will be mainly described.

  The waste liquid purification unit (60C) of this embodiment includes a waste liquid purification tank (61), a discharge unit disposed in the waste liquid purification tank (61), and an ultrasonic wave generation unit (94). The discharge unit includes an electrode pair (564, 565) provided in the waste liquid purification tank (61), a power supply unit (70) connected to the electrode pair (564, 565), and a bubble generation unit (520). Have. The ultrasonic generator (94) is installed at the bottom of the waste liquid purification tank (61).

  In the waste liquid purification unit (60C) of the present embodiment, the power supply unit (70) is supplied with a high voltage pulse voltage to the first electrode (64) and the second electrode (565).

  Further, an insulating casing surrounding the first electrode (564) may not be provided. The first electrode (564) and the second electrode (565) are both plate-shaped and are installed on the side surfaces in the waste liquid purification tank (61) so as to face each other.

  The bubble generating unit 520 is a nozzle (discharging means) provided at least between the electrode pair (564, 565) and lower than the electrode pair (564, 565), such as the bottom of the waste liquid purification tank (61). ) (519) and an air pump (sending means) (518) for sending a gas such as air to the nozzle (519). The gas sent out by the air pump (518) is sent into the waste liquid purification tank (61) through the nozzle (519) to generate bubbles in the waste liquid purification tank (61). In addition, it is good also as a structure which takes in gas from the outside also as a structure which circulates the gas in a waste liquid purification tank (61).

  The configuration of the ultrasonic generator (94) may be the same as that of the first embodiment, and is preferably installed at the bottom of the waste liquid purification tank (61). However, the ultrasonic wave is applied to the liquid in the waste liquid purification tank (61). Can be placed at any position as long as it can be irradiated.

  At least during the discharge treatment, gas is sent from the nozzle (519) into the nutrient solution, and bubbles are generated. When a pulse voltage is supplied to the electrode pair (564, 565) in a state where bubbles are present in the nutrient solution, a discharge is generated inside the bubbles to generate hydroxyl radicals, and hydrogen peroxide is generated from the hydroxyl radicals. .

  Also in the waste liquid purification unit (60B) of this embodiment, it is preferable to perform control as shown in FIG. 8 or FIG.

  According to the above configuration and method, even when pulse discharge is generated between the electrode pair (564, 565), by combining with ultrasonic irradiation, high purification ability can be exhibited while suppressing the concentration of hydrogen peroxide. it can.

Embodiment 4 of the Invention
FIG. 19 is a configuration diagram showing a waste liquid purification unit (60D) according to Embodiment 4 of the present invention. In FIG. 19, the same reference numerals as those in FIG. 2 are assigned to the same configurations as those of the waste liquid purification unit (60) of the first embodiment. Moreover, in FIG. 19, description of a control part (103), an on-off valve (63), etc. is abbreviate | omitted. In the following, differences from the waste liquid purification unit (60) according to the first embodiment will be mainly described.

  The waste liquid purification unit (60D) of the present embodiment includes a waste liquid purification tank (61), a discharge part disposed in the waste liquid purification tank (61), and an ultrasonic wave generation part (94). The discharge part has an electrode pair (664, 665) and a power supply part (70) connected to the electrode pair (664, 665). The ultrasonic generator (94) is installed at the bottom of the waste liquid purification tank (61). The power supply unit (70) is configured with, for example, an AC power supply, but may be configured with a DC power supply, or may be configured with a power supply that supplies a rectangular wave or a pulse voltage.

  The electrode (664) and the electrode (665) are respectively installed on the side surfaces in the waste liquid purification tank (61) so as to face each other.

  The electrode (664) has at least one conductive part (654) and an insulating part (655) surrounding the conductive part (654). The electrode (665) has at least one conductive part (656) and an insulating part (657) surrounding the conductive part (656).

  As described above, since the areas of the exposed surface of the conductive portion (654) in the electrode (664) and the exposed surface of the conductive portion (656) in the electrode (665) are small, voltage is supplied to the electrode pair (664, 665). In this case, a concentrated portion of current density is formed on the surface of the conductive portion (654, 656). Therefore, on the surface of the conductive portion (654, 656), the liquid is vaporized by Joule heat and bubbles are formed. By continuing the voltage supply from the power supply unit (70) in a state where the exposed surface of the conductive unit (654, 656) is covered by the bubbles, a discharge is generated inside the bubbles.

  In addition, what is necessary is just to make the specific structure of an ultrasonic wave generation part (94) the same as that of Embodiment 1, and it is preferable to install in the bottom part of a waste liquid purification tank (61), but in a waste liquid purification tank (61) As long as the liquid can be irradiated with ultrasonic waves, it can be installed at any position.

  Even with the above configuration, by combining discharge between the electrode pair (664, 665) and ultrasonic irradiation, it is possible to exhibit a high purification ability while suppressing the concentration of hydrogen peroxide.

  Also in the waste liquid purification unit (60D) of this embodiment, it is preferable to perform control as shown in FIG.

  In the configurations of the second to fourth embodiments, a copper plate (69) as an ion supply unit or an adsorption filter (80) may be provided in the waste liquid purification tank (61).

<< Modified example of hydroponics system >>
In each embodiment, the hydroponic cultivation system (10) is configured to circulate the nutrient solution in the cultivation operation mode, but is not limited thereto. For example, as shown in FIG. The nutrient solution that has passed through) may be allowed to flow into the discharge pipe (53) without being reused.

<Configuration of ion supply unit>
In each embodiment, the discharge pipe (53) was made into copper piping, and the example which made the discharge pipe (53) into the ion supply part of a copper ion was shown. However, the ion supply unit can use, for example, an iron pipe that generates iron ions. Similarly, an iron plate can be used instead of the copper plate (69) in the waste liquid purification tank (61). Since iron ions, like copper ions, promote the Fenton reaction in the presence of hydrogen peroxide, the amount of hydroxyl radicals generated can be increased. However, the ion supply unit may not be provided.

  The position where the waste liquid purification unit (60) is provided is an example. In each embodiment, the waste liquid purification unit (60) is provided in the middle of the discharge pipe (53). For example, the waste liquid purification unit (60) may be provided at the upstream end or the downstream end of the discharge pipe (53). Good. That is, the waste liquid purification unit (60) may be provided anywhere on the discharge pipe (53).

  INDUSTRIAL APPLICATION This invention is useful for the waste liquid purification apparatus of a hydroponic cultivation system, and is especially useful for the waste liquid purification apparatus provided with the discharge pipe for discharging | emitting waste liquid to a general river.

DESCRIPTION OF SYMBOLS 10 Hydroponics system 51 Piping 52 Piping 53 Discharge pipe 53a Upstream side discharge part 53b Downstream side discharge part 54 Three-way valve 60 Waste liquid purification unit 60B Waste liquid purification unit 60C Waste liquid purification unit 60D Waste liquid purification unit 61 Waste liquid purification tank 62 Discharge part 63 Opening and closing Valve 64 First electrode 64a End portion 65 Second electrode 65a Electrode main body 65b Eave portion 65c Inner cylinder portion 65d Connecting portion 66 Through hole 67 Cylindrical space 68 Leakage prevention material 69 Copper plate 69a Through hole 70 Power supply portion 71 Insulating casing 72 Case main body 72a Side wall part 72b Bottom part 73 Lid part 74 Opening 76 Base part 76a Insertion port 77 Cylindrical wall part 78 Annular convex part 80 Adsorption filter 94 Ultrasonic wave generation part 95 Piezoelectric ceramic plate 96 Metal plate 97 Case 97a Metal case 101 Cultivation floor 102 Pump 103 Control Part 200 plant 307 sensor 308 Ultrasonic waveform generator 309 Amplifier 464 Electrode 465 Electrode 471a Insulating casing 471b Insulating casing 473a Lid 473b Lid 474a Open 474b Open 480a Case main body 480b Case main body 518 Air pump 519 Nozzle 520 Bubble generator 564 First electrode 565 Second electrode 654 Conductive part 655 Insulating part 656 Conductive part 657 Insulating part 664 Electrode 665 Electrode

Claims (8)

A waste liquid purification device for hydroponic cultivation system (10),
The hydroponic system (10)
A cultivation floor (101) for planting,
An introduction pipe (52) for introducing a nutrient solution into the cultivation bed (101);
A discharge pipe (53) for discharging the nutrient solution out of the system (10) as a waste solution;
A waste liquid purification unit (60) for purifying the waste liquid,
The waste liquid purification unit (60) has a discharge part (62) for discharging in the waste liquid, and an ultrasonic generation part (94) for irradiating the waste liquid with ultrasonic waves,
The discharge unit (62) applies a voltage to the electrode pair (64, 65, 464, 465, 564, 565, 664, 665) that causes the discharge in the waste liquid and the electrode pair (64, 65, 464, 465, 564, 565, 664, 665). Power supply unit (70), and is configured to generate hydroxyl radicals in the waste liquid by the discharge,
The ultrasonic generator (94) is configured to convert the hydrogen peroxide in the waste liquid generated by the generated hydroxyl radicals to change into the hydroxyl radicals. A control unit (103) for controlling operation and stop of the discharge unit (62) and the ultrasonic wave generation unit (94);
The control unit (103) includes the discharge unit (62) and the ultrasonic wave generation unit (94) so that the concentration of hydrogen peroxide contained in the waste liquid in the waste liquid purification tank (61) is within a predetermined range. The waste liquid purifying apparatus according to claim 1, wherein operation and stop are controlled. The control unit (103) has a concentration of hydrogen peroxide contained in the waste liquid in the waste liquid purification tank (61).
Until the preset lower limit value is reached, the discharge part (62) is in an operating state, the ultrasonic wave generation part (94) is in a stopped state,
After reaching the lower limit, until the preset upper limit is reached, the discharge part (62) and the ultrasonic wave generation part (94) are in an operating state,
The said discharge part (62) is made into a stop state and the said ultrasonic wave generation part (94) is made into an operation state after reaching the said upper limit, until it reaches the said lower limit. Waste liquid purification equipment.   The waste liquid purification apparatus according to claim 2 or 3, further comprising a sensor for measuring a concentration of hydrogen peroxide contained in the waste liquid in the waste liquid purification tank (61). The electrode pair (564,565) is composed of plate-like electrodes arranged to face each other,
The power supply unit (70) is a pulse power supply that applies a pulse voltage to the electrode pair (564,565),
The said discharge part (62) has the bubble generation part (520) which generate | occur | produces a bubble in the said waste liquid between the said electrode pair (564,565), The any one of Claims 1-4 characterized by the above-mentioned. The waste liquid purifier according to the item.   The said exhaust pipe (53) is provided with the ion supply part (53,69) which supplies a copper ion or an iron ion in the waste liquid in this exhaust pipe (53). The waste liquid purification apparatus according to any one of 5. The waste liquid purification unit includes:
A water storage part (61) connected to the discharge pipe (53), in which waste liquid is stored and the discharge part (62) is accommodated;
An on-off valve (63) disposed downstream of the water reservoir (61);
Batch processing means (61, 63, 103) for repeatedly executing a process of discharging the stored waste liquid out of the water storage part (61) after the waste liquid is stored in the water storage part (61) and discharging is performed for a predetermined time. The waste liquid purification apparatus according to any one of claims 1 to 6, wherein the apparatus is a waste liquid purification apparatus.   The waste liquid purification unit is provided in the vicinity of the upstream side or the downstream side of the discharge part (62), and has an adsorption part (80) for adsorbing a chemical substance in the waste liquid. The waste liquid purification apparatus of any one of -7.

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